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Pandit SV, Lampe JW, Silver AE. Recurrence of ventricular fibrillation in out-of-hospital cardiac arrest: Clinical evidence and underlying ionic mechanisms. J Physiol 2024. [PMID: 38661672 DOI: 10.1113/jp284621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 03/08/2024] [Indexed: 04/26/2024] Open
Abstract
Defibrillation remains the optimal therapy for terminating ventricular fibrillation (VF) in out-of-hospital cardiac arrest (OHCA) patients, with reported shock success rates of ∼90%. A key persistent challenge, however, is the high rate of VF recurrence (∼50-80%) seen during post-shock cardiopulmonary resuscitation (CPR). Studies have shown that the incidence and time spent in recurrent VF are negatively associated with neurologically-intact survival. Recurrent VF also results in the administration of extra shocks at escalating energy levels, which can cause cardiac dysfunction. Unfortunately, the mechanisms underlying recurrent VF remain poorly understood. In particular, the role of chest-compressions (CC) administered during CPR in mediating recurrent VF remains controversial. In this review, we first summarize the available clinical evidence for refibrillation occurring during CPR in OHCA patients, including the postulated contribution of CC and non-CC related pathways. Next, we examine experimental studies highlighting how CC can re-induce VF via direct mechano-electric feedback. We postulate the ionic mechanisms involved by comparison with similar phenomena seen in commotio cordis. Subsequently, the hypothesized contribution of partial cardiac reperfusion (either as a result of CC or CC independent organized rhythm) in re-initiating VF in a globally ischaemic heart is examined. An overview of the proposed ionic mechanisms contributing to VF recurrence in OHCA during CPR from a cellular level to the whole heart is outlined. Possible therapeutic implications of the proposed mechanistic theories for VF recurrence in OHCA are briefly discussed.
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Affiliation(s)
- Sandeep V Pandit
- University of Memphis, ZOLL Medical, Chelmsford, Massachusetts, USA
| | - Joshua W Lampe
- University of Pennsylvania, ZOLL Medical, Chelmsford, Massachusetts, USA
| | - Annemarie E Silver
- University of Colorado Boulder, ZOLL Medical, Chelmsford, Massachusetts, USA
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2
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Bergeman AT, Postema PG, Wilde AAM, van der Werf C. Pharmacological treatment of short-coupled idiopathic ventricular fibrillation: A review. Indian Pacing Electrophysiol J 2023; 23:77-83. [PMID: 36933619 PMCID: PMC10160784 DOI: 10.1016/j.ipej.2023.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 03/11/2023] [Accepted: 03/15/2023] [Indexed: 03/18/2023] Open
Abstract
Short-coupled idiopathic ventricular fibrillation (IVF) is a subtype of IVF in which episodes of polymorphic ventricular tachycardia or ventricular fibrillation are initiated by short-coupled premature ventricular contractions (PVCs). Our understanding of the pathophysiology is evolving, with evidence suggesting that these malignant PVCs originate from the Purkinje system. In most cases, the genetic underpinning has not been identified. Whereas the implantation of an implantable cardioverter-defibrillator is uncontroversial, the choice of pharmacological treatment is the subject of discussion. In this review, we summarize the available knowledge on pharmacological therapy in short-coupled IVF and provide our recommendations for management of patients with this syndrome.
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Affiliation(s)
- A T Bergeman
- Heart Centre, Department of Cardiology, Amsterdam UMC Location AMC, University of Amsterdam, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias, Amsterdam, the Netherlands
| | - P G Postema
- Heart Centre, Department of Cardiology, Amsterdam UMC Location AMC, University of Amsterdam, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias, Amsterdam, the Netherlands
| | - A A M Wilde
- Heart Centre, Department of Cardiology, Amsterdam UMC Location AMC, University of Amsterdam, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias, Amsterdam, the Netherlands
| | - C van der Werf
- Heart Centre, Department of Cardiology, Amsterdam UMC Location AMC, University of Amsterdam, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias, Amsterdam, the Netherlands.
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3
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Tsumoto K, Kurata Y. Bifurcations and Proarrhythmic Behaviors in Cardiac Electrical Excitations. Biomolecules 2022; 12:459. [PMID: 35327651 PMCID: PMC8946197 DOI: 10.3390/biom12030459] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 03/09/2022] [Accepted: 03/14/2022] [Indexed: 12/23/2022] Open
Abstract
The heart is a hierarchical dynamic system consisting of molecules, cells, and tissues, and acts as a pump for blood circulation. The pumping function depends critically on the preceding electrical activity, and disturbances in the pattern of excitation propagation lead to cardiac arrhythmia and pump failure. Excitation phenomena in cardiomyocytes have been modeled as a nonlinear dynamical system. Because of the nonlinearity of excitation phenomena, the system dynamics could be complex, and various analyses have been performed to understand the complex dynamics. Understanding the mechanisms underlying proarrhythmic responses in the heart is crucial for developing new ways to prevent and control cardiac arrhythmias and resulting contractile dysfunction. When the heart changes to a pathological state over time, the action potential (AP) in cardiomyocytes may also change to a different state in shape and duration, often undergoing a qualitative change in behavior. Such a dynamic change is called bifurcation. In this review, we first summarize the contribution of ion channels and transporters to AP formation and our knowledge of ion-transport molecules, then briefly describe bifurcation theory for nonlinear dynamical systems, and finally detail its recent progress, focusing on the research that attempts to understand the developing mechanisms of abnormal excitations in cardiomyocytes from the perspective of bifurcation phenomena.
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Affiliation(s)
| | - Yasutaka Kurata
- Department of Physiology II, Kanazawa Medical University, Uchinada 920-0293, Japan;
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4
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Kani K, Fujiu K. Electrical Storm. Int Heart J 2021; 62:1195-1198. [PMID: 34853216 DOI: 10.1536/ihj.21-662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Kunihiro Kani
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo
| | - Katsuhito Fujiu
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo
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5
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Estimating ectopic beat probability with simplified statistical models that account for experimental uncertainty. PLoS Comput Biol 2021; 17:e1009536. [PMID: 34665814 PMCID: PMC8577785 DOI: 10.1371/journal.pcbi.1009536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 11/09/2021] [Accepted: 10/06/2021] [Indexed: 11/21/2022] Open
Abstract
Ectopic beats (EBs) are cellular arrhythmias that can trigger lethal arrhythmias. Simulations using biophysically-detailed cardiac myocyte models can reveal how model parameters influence the probability of these cellular arrhythmias, however such analyses can pose a huge computational burden. Here, we develop a simplified approach in which logistic regression models (LRMs) are used to define a mapping between the parameters of complex cell models and the probability of EBs (P(EB)). As an example, in this study, we build an LRM for P(EB) as a function of the initial value of diastolic cytosolic Ca2+ concentration ([Ca2+]iini), the initial state of sarcoplasmic reticulum (SR) Ca2+ load ([Ca2+]SRini), and kinetic parameters of the inward rectifier K+ current (IK1) and ryanodine receptor (RyR). This approach, which we refer to as arrhythmia sensitivity analysis, allows for evaluation of the relationship between these arrhythmic event probabilities and their associated parameters. This LRM is also used to demonstrate how uncertainties in experimentally measured values determine the uncertainty in P(EB). In a study of the role of [Ca2+]SRini uncertainty, we show a special property of the uncertainty in P(EB), where with increasing [Ca2+]SRini uncertainty, P(EB) uncertainty first increases and then decreases. Lastly, we demonstrate that IK1 suppression, at the level that occurs in heart failure myocytes, increases P(EB). An ectopic beat is an abnormal cellular electrical event which can trigger dangerous arrhythmias in the heart. Complex biophysical models of the cardiac myocyte can be used to reveal how cell properties affect the probability of ectopic beats. However, such analyses can pose a huge computational burden. We develop a simplified approach that enables a highly complex biophysical model to be reduced to a rather simple statistical model from which the functional relationship between myocyte model parameters and the probability of an ectopic beat is determined. We refer to this approach as arrhythmia sensitivity analysis. Given the efficiency of our approach, we also use it to demonstrate how uncertainties in experimentally measured myocyte model parameters determine the uncertainty in ectopic beat probability. We find that, with increasing model parameter uncertainty, the uncertainty in probability of ectopic beat first increases and then decreases. In general, our approach can efficiently analyze the relationship between cardiac myocyte parameters and the probability of ectopic beats and can be used to study how uncertainty of these cardiac myocyte parameters influences the ectopic beat probability.
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6
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Takahashi M, Yokoshiki H, Mitsuyama H, Watanabe M, Temma T, Kamada R, Hagiwara H, Takahashi Y, Anzai T. SK channel blockade prevents hypoxia-induced ventricular arrhythmias through inhibition of Ca 2+/voltage uncoupling in hypertrophied hearts. Am J Physiol Heart Circ Physiol 2021; 320:H1456-H1469. [PMID: 33635168 DOI: 10.1152/ajpheart.00777.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 02/17/2021] [Indexed: 11/22/2022]
Abstract
Ventricular arrhythmia (VA) is the major cause of death in patients with left ventricular (LV) hypertrophy and/or acute ischemia. We hypothesized that apamin, a blocker of small-conductance Ca2+-activated K+ (SK) channels, alters Ca2+ handling and exhibits anti-arrhythmic effects in ventricular myocardium. Spontaneous hypertensive rats were used as a model of LV hypertrophy. A dual optical mapping of membrane potential (Vm) and intracellular calcium (Cai) was performed during global hypoxia (GH) on the Langendorff perfusion system. The majority of pacing-induced VAs during GH were initiated by triggered activities. Pretreatment of apamin (100 nmol/L) significantly inhibited the VA inducibility. Compared with SK channel blockers (apamin and NS8593), non-SK channel blockers (glibenclamide and 4-AP) did not exhibit anti-arrhythmic effects. Apamin prevented not only action potential duration (APD80) shortening (-18.7 [95% confidence interval, -35.2 to -6.05] ms vs. -2.75 [95% CI, -10.45 to 12.65] ms, P = 0.04) but also calcium transient duration (CaTD80) prolongation (14.52 [95% CI, 8.8-20.35] ms vs. 3.85 [95% CI, -3.3 to 12.1] ms, P < 0.01), thereby reducing CaTD80 - APD80, which denotes "Cai/Vm uncoupling" (33.22 [95% CI, 22-48.4] ms vs. 6.6 [95% CI, 0-14.85] ms, P < 0.01). The reduction of Cai/Vm uncoupling was attributable to less prolonged Ca2+ decay constant and suppression of diastolic Cai increase by apamin. The inhibition of VA inducibility and changes in APs/CaTs parameters caused by apamin was negated by the addition of ouabain, an inhibitor of Na+/K+ pump. Apamin attenuates APD shortening, Ca2+ handling abnormalities, and Cai/Vm uncoupling, leading to inhibition of VA occurrence in hypoxic hypertrophied hearts.NEW & NOTEWORTHY We demonstrated that hypoxia-induced ventricular arrhythmias were mainly initiated by Ca2+-loaded triggered activities in hypertrophied hearts. The blockades of small-conductance Ca2+-activated K+ channels, especially "apamin," showed anti-arrhythmic effects by alleviation of not only action potential duration shortening but also Ca2+ handling abnormalities, most notably the "Ca2+/voltage uncoupling."
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Affiliation(s)
- Masayuki Takahashi
- Department of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan
- Department of Cardiovascular Medicine, National Hospital Organization Hokkaido Medical Center, Sapporo, Japan
| | - Hisashi Yokoshiki
- Department of Cardiovascular Medicine, Sapporo City General Hospital, Sapporo, Japan
| | - Hirofumi Mitsuyama
- Department of Cardiovascular Medicine, Hokkaido Ohno Memorial Hospital, Sapporo, Japan
| | - Masaya Watanabe
- Department of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Taro Temma
- Department of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Rui Kamada
- Department of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Hikaru Hagiwara
- Department of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Yumi Takahashi
- Department of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Toshihisa Anzai
- Department of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan
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The regulation of the small-conductance calcium-activated potassium current and the mechanisms of sex dimorphism in J wave syndrome. Pflugers Arch 2021; 473:491-506. [PMID: 33411079 DOI: 10.1007/s00424-020-02500-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 11/20/2020] [Accepted: 11/25/2020] [Indexed: 12/16/2022]
Abstract
Apamin-sensitive small-conductance calcium-activated potassium (SK) current (IKAS) plays an important role in cardiac repolarization under a variety of physiological and pathological conditions. The regulation of cardiac IKAS relies on SK channel expression, intracellular Ca2+, and interaction between SK channel and intracellular Ca2+. IKAS activation participates in multiple types of arrhythmias, including atrial fibrillation, ventricular tachyarrhythmias, and automaticity and conduction abnormality. Recently, sex dimorphisms in autonomic control have been noticed in IKAS activation, resulting in sex-differentiated action potential morphology and arrhythmogenesis. This review provides an update on the Ca2+-dependent regulation of cardiac IKAS and the role of IKAS on arrhythmias, with a special focus on sex differences in IKAS activation. We propose that sex dimorphism in autonomic control of IKAS may play a role in J wave syndrome.
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Shah C, Jiwani S, Limbu B, Weinberg S, Deo M. Delayed afterdepolarization-induced triggered activity in cardiac purkinje cells mediated through cytosolic calcium diffusion waves. Physiol Rep 2020; 7:e14296. [PMID: 31872561 PMCID: PMC6928245 DOI: 10.14814/phy2.14296] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Cardiac Purkinje cells (PCs) are more susceptible to action potential abnormalities as compared to ventricular myocytes (VMs), which could be associated with their distinct intracellular calcium handling. We developed a detailed biophysical model of a mouse cardiac PC, which importantly reproduces the experimentally observed biphasic cytosolic calcium waves. The model includes a stochastic gating formulation for the opening and closing of ryanodine receptor (RyR) channels, simulated with a Monte Carlo method, to accurately reproduce cytosolic calcium wave propagation and the effects of spontaneous calcium release events. Simulations predict that during an action potential, smaller cytosolic calcium wavelets propagated from the sarcolemma towards the center of the cell and initiated larger magnitude cell‐wide calcium waves via a calcium‐induced‐calcium release mechanism. In the presence of RyR mutations, frequent spontaneous calcium leaks from sarcoplasmic reticulum (SR) initiated calcium waves, which upon reaching the cell periphery produced delayed afterdepolarizations (DADs) via sodium‐calcium exchanger (NCX) and T‐type calcium (ICaT) channel activation. In the presence of isoproterenol‐mediated effects, DADs induced triggered activity by reactivation of fast sodium channels. Based on our model, we found that the activation of either L‐type calcium channels (ICaL), ICaT, sodium‐potassium exchanger (INaK) or NCX is sufficient for occurrence of triggered activity; however, a partial blockade of ICaT or INaK is essential for its successful termination. Our modeling study highlights valuable insights into the mechanisms of DAD‐induced triggered activity mediated via cytosolic calcium waves in cardiac PCs and may elucidate the increased arrhythmogeneity in PCs.
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Affiliation(s)
- Chirag Shah
- School of Medicine, Eastern Virginia Medical School, Norfolk, Virginia
| | - Sohel Jiwani
- Department of Engineering, Norfolk State University, Norfolk, Virginia
| | - Bijay Limbu
- Department of Engineering, Norfolk State University, Norfolk, Virginia
| | - Seth Weinberg
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia.,Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio
| | - Makarand Deo
- Department of Engineering, Norfolk State University, Norfolk, Virginia
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9
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Reilly L, Alvarado FJ, Lang D, Abozeid S, Van Ert H, Spellman C, Warden J, Makielski JC, Glukhov AV, Eckhardt LL. Genetic Loss of IK1 Causes Adrenergic-Induced Phase 3 Early Afterdepolariz ations and Polymorphic and Bidirectional Ventricular Tachycardia. Circ Arrhythm Electrophysiol 2020; 13:e008638. [PMID: 32931337 PMCID: PMC7574954 DOI: 10.1161/circep.120.008638] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 06/23/2020] [Indexed: 11/16/2022]
Abstract
BACKGROUND Arrhythmia syndromes associated with KCNJ2 mutations have been described clinically; however, little is known of the underlying arrhythmia mechanism. We create the first patient inspired KCNJ2 transgenic mouse and study effects of this mutation on cardiac function, IK1, and Ca2+ handling, to determine the underlying cellular arrhythmic pathogenesis. METHODS A cardiac-specific KCNJ2-R67Q mouse was generated and bred for heterozygosity (R67Q+/-). Echocardiography was performed at rest, under anesthesia. In vivo ECG recording and whole heart optical mapping of intact hearts was performed before and after adrenergic stimulation in wild-type (WT) littermate controls and R67Q+/- mice. IK1 measurements, action potential characterization, and intracellular Ca2+ imaging from isolated ventricular myocytes at baseline and after adrenergic stimulation were performed in WT and R67Q+/- mice. RESULTS R67Q+/- mice (n=17) showed normal cardiac function, structure, and baseline electrical activity compared with WT (n=10). Following epinephrine and caffeine, only the R67Q+/- mice had bidirectional ventricular tachycardia, ventricular tachycardia, frequent ventricular ectopy, and/or bigeminy and optical mapping demonstrated high prevalence of spontaneous and sustained ventricular arrhythmia. Both R67Q+/- (n=8) and WT myocytes (n=9) demonstrated typical n-shaped IK1IV relationship; however, following isoproterenol, max outward IK1 increased by ≈20% in WT but decreased by ≈24% in R67Q+/- (P<0.01). R67Q+/- myocytes (n=5) demonstrated prolonged action potential duration at 90% repolarization and after 10 nmol/L isoproterenol compared with WT (n=7; P<0.05). Ca2+ transient amplitude, 50% decay rate, and sarcoplasmic reticulum Ca2+ content were not different between WT (n=18) and R67Q+/- (n=16) myocytes. R67Q+/- myocytes (n=10) under adrenergic stimulation showed frequent spontaneous development of early afterdepolarizations that occurred at phase 3 of action potential repolarization. CONCLUSIONS KCNJ2 mutation R67Q+/- causes adrenergic-dependent loss of IK1 during terminal repolarization and vulnerability to phase 3 early afterdepolarizations. This model clarifies a heretofore unknown arrhythmia mechanism and extends our understanding of treatment implications for patients with KCNJ2 mutation.
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Affiliation(s)
- Louise Reilly
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Francisco J Alvarado
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Di Lang
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Sara Abozeid
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Hannah Van Ert
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Cordell Spellman
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Jarrett Warden
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Jonathan C Makielski
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Alexey V Glukhov
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Lee L Eckhardt
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
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Nielsen JC, Lin YJ, de Oliveira Figueiredo MJ, Sepehri Shamloo A, Alfie A, Boveda S, Dagres N, Di Toro D, Eckhardt LL, Ellenbogen K, Hardy C, Ikeda T, Jaswal A, Kaufman E, Krahn A, Kusano K, Kutyifa V, Lim HS, Lip GYH, Nava-Townsend S, Pak HN, Rodríguez Diez G, Sauer W, Saxena A, Svendsen JH, Vanegas D, Vaseghi M, Wilde A, Bunch TJ, Buxton AE, Calvimontes G, Chao TF, Eckardt L, Estner H, Gillis AM, Isa R, Kautzner J, Maury P, Moss JD, Nam GB, Olshansky B, Pava Molano LF, Pimentel M, Prabhu M, Tzou WS, Sommer P, Swampillai J, Vidal A, Deneke T, Hindricks G, Leclercq C. European Heart Rhythm Association (EHRA)/Heart Rhythm Society (HRS)/Asia Pacific Heart Rhythm Society (APHRS)/Latin American Heart Rhythm Society (LAHRS) expert consensus on risk assessment in cardiac arrhythmias: use the right tool for the right outcome, in the right population. Europace 2020; 22:1147-1148. [PMID: 32538434 PMCID: PMC7400488 DOI: 10.1093/europace/euaa065] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Affiliation(s)
| | - Yenn-Jiang Lin
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | | | - Alireza Sepehri Shamloo
- Department of Electrophysiology, Leipzig Heart Center at University of Leipzig, Leipzig, Germany
| | - Alberto Alfie
- Division of Electrophysiology, Instituto Cardiovascular Adventista, Clinica Bazterrica, Buenos Aires, Argentina
| | - Serge Boveda
- Department of Cardiology, Clinique Pasteur, Toulouse, France
| | - Nikolaos Dagres
- Department of Electrophysiology, Leipzig Heart Center at University of Leipzig, Leipzig, Germany
| | - Dario Di Toro
- Department of Cardiology, Division of Electrophysiology, Argerich Hospital and CEMIC, Buenos Aires, Argentina
| | - Lee L Eckhardt
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Kenneth Ellenbogen
- Division of Cardiology, Virginia Commonwealth University School of Medicine, Richmond, USA
| | - Carina Hardy
- Arrhythmia Unit, Heart Institute, University of São, Paulo Medical School, Instituto do Coração -InCor- Faculdade de Medicina de São Paulo-São Paulo, Brazil
| | - Takanori Ikeda
- Department of Cardiovascular Medicine, Faculty of Medicine, Toho University, Japan
| | - Aparna Jaswal
- Department of Cardiac Electrophysiology, Fortis Escorts Heart Institute, Okhla Road, New Delhi, India
| | - Elizabeth Kaufman
- The Heart and Vascular Research Center, Metrohealth Campus of Case Western Reserve University, Cleveland, OH, USA
| | - Andrew Krahn
- Division of Cardiology, Department of Medicine, University of British Columbia, Vancouver, Canada
| | - Kengo Kusano
- Division of Arrhythmia and Electrophysiology, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Valentina Kutyifa
- University of Rochester, Medical Center, Rochester, USA
- Semmelweis University, Heart and Vascular Center, Budapest, Hungary
| | - Han S Lim
- Department of Cardiology, Austin Health, Melbourne, VIC, Australia
- University of Melbourne, Melbourne, VIC, Australia
| | - Gregory Y H Lip
- Liverpool Centre for Cardiovascular Science, University of Liverpool and Liverpool Heart & Chest Hospital, Liverpool, UK
- Aalborg Thrombosis Research Unit, Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
| | - Santiago Nava-Townsend
- Department of Electrocardiology, National Institute of Cardiology “Ignacio Chavez,” Mexico City, Mexico
| | - Hui-Nam Pak
- Division of Cardiology, Department of Internal Medicine, Yonsei University Health System, Seoul, Republic of Korea
| | - Gerardo Rodríguez Diez
- Department of Electrophysiology and Hemodynamic, Arrhytmias Unity, CMN 20 de Noviembre, ISSSTE, Mexico City, Mexico
| | - William Sauer
- Cardiovascular Division, Brigham and Women s Hospital and Harvard Medical School, Boston, USA
| | - Anil Saxena
- Department of Cardiac Electrophysiology, Fortis Escorts Heart Institute, Okhla Road, New Delhi, India
| | - Jesper Hastrup Svendsen
- Department of Cardiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Diego Vanegas
- Hospital Militar Central, Fundarritmia, Bogotá, Colombia
| | - Marmar Vaseghi
- Los Angeles UCLA Cardiac Arrhythmia Center, UCLA Health System, David Geffen School of Medicine, at UCLA, USA
| | - Arthur Wilde
- Amsterdam UMC, University of Amsterdam, Heart Center; Department of Clinical and Experimental Cardiology, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - T Jared Bunch
- Department of Medicine, Intermountain Heart Institute, Intermountain Medical Center, Salt Lake City, USA
| | | | - Alfred E Buxton
- Department of Medicine, The Richard A. and Susan F. Smith Center for Outcomes Research in Cardiology, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | | | - Tze-Fan Chao
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Lars Eckardt
- Department for Cardiology, Electrophysiology, University Hospital Münster, Münster, Germany
| | - Heidi Estner
- Department of Medicine, I, University Hospital Munich, Ludwig-Maximilians University, Munich, Germany
| | - Anne M Gillis
- University of Calgary - Libin Cardiovascular Institute of Alberta, Calgary, AB, Canada
| | - Rodrigo Isa
- Clínica RedSalud Vitacura and Hospital el Carmen de Maipú, Santiago, Chile
| | - Josef Kautzner
- Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | | | - Joshua D Moss
- Department of Cardiac Electrophysiology, University of California San Francisco, San Francisco, USA
| | - Gi-Byung Nam
- Division of Cardiology, Asan Medical Center, University of Ulsan, College of Medicine, Seoul, Republic of Korea
| | - Brian Olshansky
- University of Iowa Carver College of Medicine, Iowa City, USA
| | | | - Mauricio Pimentel
- Cardiology Division, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil
| | - Mukund Prabhu
- Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, India
| | - Wendy S Tzou
- Department of Cardiology/Cardiac Electrophysiology, University of Colorado Anschutz Medical Campus, Aurora, USA
| | - Philipp Sommer
- Clinic for Electrophysiology, Herz- und Diabeteszentrum, Clinic for Electrophysiology, Ruhr-Universität Bochum, Bad Oeynhausen, Germany
| | | | - Alejandro Vidal
- Division of Cardiology, McGill University Health Center, Montreal, Canada
| | - Thomas Deneke
- Clinic for Cardiology II (Interventional Electrophysiology), Heart Center Bad Neustadt, Bad Neustadt a.d. Saale, Germany
| | - Gerhard Hindricks
- Department of Electrophysiology, Leipzig Heart Center at University of Leipzig, Leipzig, Germany
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11
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Nielsen JC, Lin YJ, de Oliveira Figueiredo MJ, Sepehri Shamloo A, Alfie A, Boveda S, Dagres N, Di Toro D, Eckhardt LL, Ellenbogen K, Hardy C, Ikeda T, Jaswal A, Kaufman E, Krahn A, Kusano K, Kutyifa V, Lim HS, Lip GYH, Nava-Townsend S, Pak HN, Diez GR, Sauer W, Saxena A, Svendsen JH, Vanegas D, Vaseghi M, Wilde A, Bunch TJ, Buxton AE, Calvimontes G, Chao TF, Eckardt L, Estner H, Gillis AM, Isa R, Kautzner J, Maury P, Moss JD, Nam GB, Olshansky B, Pava Molano LF, Pimentel M, Prabhu M, Tzou WS, Sommer P, Swampillai J, Vidal A, Deneke T, Hindricks G, Leclercq C. European Heart Rhythm Association (EHRA)/Heart Rhythm Society (HRS)/Asia Pacific Heart Rhythm Society (APHRS)/Latin American Heart Rhythm Society (LAHRS) expert consensus on risk assessment in cardiac arrhythmias: use the right tool for the right outcome, in the right population. Heart Rhythm 2020; 17:e269-e316. [PMID: 32553607 DOI: 10.1016/j.hrthm.2020.05.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 05/05/2020] [Indexed: 02/07/2023]
Affiliation(s)
| | - Yenn-Jiang Lin
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | | | - Alireza Sepehri Shamloo
- Department of Electrophysiology, Leipzig Heart Center at University of Leipzig, Leipzig, Germany
| | - Alberto Alfie
- Division of Electrophysiology, Instituto Cardiovascular Adventista, Clinica Bazterrica, Buenos Aires, Argentina
| | - Serge Boveda
- Department of Cardiology, Clinique Pasteur, Toulouse, France
| | - Nikolaos Dagres
- Department of Electrophysiology, Leipzig Heart Center at University of Leipzig, Leipzig, Germany
| | - Dario Di Toro
- Department of Cardiology, Division of Electrophysiology, Argerich Hospital and CEMIC, Buenos Aires, Argentina
| | - Lee L Eckhardt
- Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Kenneth Ellenbogen
- Division of Cardiology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, USA
| | - Carina Hardy
- Arrhythmia Unit, Heart Institute, University of São Paulo Medical School, Instituto do Coração -InCor- Faculdade de Medicina de São Paulo, São Paulo, Brazil
| | - Takanori Ikeda
- Department of Cardiovascular Medicine, Faculty of Medicine, Toho University, Tokyo, Japan
| | - Aparna Jaswal
- Department of Cardiac Electrophysiology, Fortis Escorts Heart Institute, Okhla Road, New Delhi, India
| | - Elizabeth Kaufman
- The Heart and Vascular Research Center, Metrohealth Campus of Case Western Reserve University, Cleveland, Ohio, USA
| | - Andrew Krahn
- Division of Cardiology, Department of Medicine, University of British Columbia, Vancouver, Canada
| | - Kengo Kusano
- Division of Arrhythmia and Electrophysiology, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Valentina Kutyifa
- University of Rochester, Medical Center, Rochester, New York, USA; Semmelweis University, Heart and Vascular Center, Budapest, Hungary
| | - Han S Lim
- Department of Cardiology, Austin Health, Melbourne, VIC, Australia; University of Melbourne, Melbourne, VIC, Australia
| | - Gregory Y H Lip
- Liverpool Centre for Cardiovascular Science, University of Liverpool and Liverpool Heart & Chest Hospital, Liverpool, UK; Aalborg Thrombosis Research Unit, Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
| | - Santiago Nava-Townsend
- Department of Electrocardiology, National Institute of Cardiology "Ignacio Chavez," Mexico City, Mexico
| | - Hui-Nam Pak
- Division of Cardiology, Department of Internal Medicine, Yonsei University Health System, Seoul, Republic of Korea
| | - Gerardo Rodríguez Diez
- Department of Electrophysiology and Hemodynamic, Arrhytmias Unity, CMN 20 de Noviembre, ISSSTE, Mexico City, Mexico
| | - William Sauer
- Cardiovascular Division, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Anil Saxena
- Department of Cardiac Electrophysiology, Fortis Escorts Heart Institute, Okhla Road, New Delhi, India
| | - Jesper Hastrup Svendsen
- Department of Cardiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Diego Vanegas
- Hospital Militar Central, Fundarritmia, Bogotá, Colombia
| | - Marmar Vaseghi
- UCLA Cardiac Arrhythmia Center, UCLA Health System, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Arthur Wilde
- Amsterdam UMC, University of Amsterdam, Heart Center, Department of Clinical and Experimental Cardiology, Amsterdam, the Netherlands
| | - T Jared Bunch
- Department of Medicine, Intermountain Heart Institute, Intermountain Medical Center, Salt Lake City, Utah, USA
| | | | - Alfred E Buxton
- Department of Medicine, The Richard A. and Susan F. Smith Center for Outcomes Research in Cardiology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
| | | | - Tze-Fan Chao
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Lars Eckardt
- Department for Cardiology, Electrophysiology, University Hospital Münster, Münster, Germany
| | - Heidi Estner
- Department of Medicine, I, University Hospital Munich, Ludwig-Maximilians University, Munich, Germany
| | - Anne M Gillis
- University of Calgary - Libin Cardiovascular Institute of Alberta, Calgary, Canada
| | - Rodrigo Isa
- Clínica RedSalud Vitacura and Hospital el Carmen de Maipú, Santiago, Chile
| | - Josef Kautzner
- Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | | | - Joshua D Moss
- Department of Cardiac Electrophysiology, University of California San Francisco, San Francisco, California, USA
| | - Gi-Byung Nam
- Division of Cardiology, Asan Medical Center, University of Ulsan, College of Medicine, Seoul, Republic of Korea
| | - Brian Olshansky
- University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | | | - Mauricio Pimentel
- Cardiology Division, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil
| | - Mukund Prabhu
- Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, India
| | - Wendy S Tzou
- Department of Cardiology/Cardiac Electrophysiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Philipp Sommer
- Clinic for Electrophysiology, Herz- und Diabeteszentrum, Clinic for Electrophysiology, Ruhr-Universität Bochum, Bad Oeynhausen, Germany
| | | | - Alejandro Vidal
- Division of Cardiology, McGill University Health Center, Montreal, Canada
| | - Thomas Deneke
- Clinic for Cardiology II (Interventional Electrophysiology), Heart Center Bad Neustadt, Bad Neustadt a.d. Saale, Germany
| | - Gerhard Hindricks
- Department of Electrophysiology, Leipzig Heart Center at University of Leipzig, Leipzig, Germany
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12
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Nielsen JC, Lin YJ, de Oliveira Figueiredo MJ, Sepehri Shamloo A, Alfie A, Boveda S, Dagres N, Di Toro D, Eckhardt LL, Ellenbogen K, Hardy C, Ikeda T, Jaswal A, Kaufman E, Krahn A, Kusano K, Kutyifa V, S Lim H, Lip GYH, Nava-Townsend S, Pak HN, Rodríguez Diez G, Sauer W, Saxena A, Svendsen JH, Vanegas D, Vaseghi M, Wilde A, Bunch TJ, Buxton AE, Calvimontes G, Chao TF, Eckardt L, Estner H, Gillis AM, Isa R, Kautzner J, Maury P, Moss JD, Nam GB, Olshansky B, Molano LFP, Pimentel M, Prabhu M, Tzou WS, Sommer P, Swampillai J, Vidal A, Deneke T, Hindricks G, Leclercq C. European Heart Rhythm Association (EHRA)/Heart Rhythm Society (HRS)/Asia Pacific Heart Rhythm Society (APHRS)/Latin American Heart Rhythm Society (LAHRS) expert consensus on risk assessment in cardiac arrhythmias: use the right tool for the right outcome, in the right population. J Arrhythm 2020; 36:553-607. [PMID: 32782627 PMCID: PMC7411224 DOI: 10.1002/joa3.12338] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Affiliation(s)
| | - Yenn-Jiang Lin
- Division of Cardiology Department of Medicine Taipei Veterans General Hospital Taipei Taiwan
| | | | - Alireza Sepehri Shamloo
- Department of Electrophysiology Leipzig Heart Center at University of Leipzig Leipzig Germany
| | - Alberto Alfie
- Division of Electrophysiology Instituto Cardiovascular Adventista Clinica Bazterrica Buenos Aires Argentina
| | - Serge Boveda
- Department of Cardiology Clinique Pasteur Toulouse France
| | - Nikolaos Dagres
- Department of Electrophysiology Leipzig Heart Center at University of Leipzig Leipzig Germany
| | - Dario Di Toro
- Division of Electrophysiology Department of Cardiology Argerich Hospital and CEMIC Buenos Aires Argentina
| | - Lee L Eckhardt
- Department of Medicine University of Wisconsin-Madison Madison WI USA
| | - Kenneth Ellenbogen
- Division of Cardiology Virginia Commonwealth University School of Medicine Richmond USA
| | - Carina Hardy
- Heart Institute University of São Paulo Medical School Arrhythmia Unit Instituto do Coração -InCor- Faculdade de Medicina de São Paulo São Paulo Brazil
| | - Takanori Ikeda
- Faculty of Medicine Department of Cardiovascular Medicine Toho University Japan
| | - Aparna Jaswal
- Department of Cardiac Electrophysiology Fortis Escorts Heart Institute New Delhi India
| | - Elizabeth Kaufman
- The Heart and Vascular Research Center Metrohealth Campus of Case Western Reserve University Cleveland OH USA
| | - Andrew Krahn
- Division of Cardiology Department of Medicine University of British Columbia Vancouver Canada
| | - Kengo Kusano
- Division of Arrthythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Osaka Japan
| | - Valentina Kutyifa
- University of Rochester Medical Center Rochester USA.,Heart and Vascular Center Semmelweis University Budapest Hungary
| | - Han S Lim
- Department of Cardiology Austin Health Melbourne VIC Australia.,Cardiovascular Medicine University of Melbourne Melbourne VIC Australia
| | - Gregory Y H Lip
- Liverpool Centre for Cardiovascular Science University of Liverpool and Liverpool Heart & Chest Hospital Liverpool UK.,Aalborg Thrombosis Research Unit Department of Clinical Medicine Aalborg University Aalborg Denmark
| | - Santiago Nava-Townsend
- Department of Electrocardiology National Institute of Cardiology "Ignacio Chavez" Mexico City Mexico
| | - Hui-Nam Pak
- Division of Cardiology Department of Internal Medicine Yonsei University Health System Seoul Republic of Korea
| | - Gerardo Rodríguez Diez
- Department of Electrophysiology and Hemodynamic Arrhytmias Unity CMN 20 de Noviembre ISSSTE Mexico City Mexico
| | - William Sauer
- Cardiovascular Division Brigham and Women's Hospital and Harvard Medical School Boston USA
| | - Anil Saxena
- Department of Cardio Electrophysiology Fortis Escorts Heart Institute New Delhi India
| | - Jesper Hastrup Svendsen
- Department of Cardiology, Rigshospitalet University of Copenhagen Copenhagen Denmark.,Amsterdam UMC University of Amsterdam Heart Center Department of Clinical and Experimental Cardiology Amsterdam The Netherlands
| | | | - Marmar Vaseghi
- UCLA Cardiac Arrhythmia Center UCLA Health System David Geffen School of Medicine, at UCLA Los Angeles USA
| | - Arthur Wilde
- Heart Center Department of Clinical and Experimental Cardiology Amsterdam UMC University of Amsterdam Amsterdam The Netherlands
| | - T Jared Bunch
- Department of Medicine Intermountain Heart Institute Intermountain Medical Center Salt Lake City USA
| | - Alfred E Buxton
- Department of Cardiology Aarhus University Hospital Skejby Denmark.,Division of Cardiology Department of Medicine Taipei Veterans General Hospital Taipei Taiwan.,Electrophysiology Service Department of Internal Medicine University of Campinas Hospital Campinas Brazil.,Department of Electrophysiology Leipzig Heart Center at University of Leipzig Leipzig Germany.,Division of Electrophysiology Instituto Cardiovascular Adventista Clinica Bazterrica Buenos Aires Argentina.,Department of Cardiology Clinique Pasteur Toulouse France.,Division of Electrophysiology Department of Cardiology Argerich Hospital and CEMIC Buenos Aires Argentina.,Department of Medicine University of Wisconsin-Madison Madison WI USA.,Division of Cardiology Virginia Commonwealth University School of Medicine Richmond USA.,Heart Institute University of São Paulo Medical School Arrhythmia Unit Instituto do Coração -InCor- Faculdade de Medicina de São Paulo São Paulo Brazil.,Faculty of Medicine Department of Cardiovascular Medicine Toho University Japan.,Department of Cardiac Electrophysiology Fortis Escorts Heart Institute New Delhi India.,The Heart and Vascular Research Center Metrohealth Campus of Case Western Reserve University Cleveland OH USA.,Division of Cardiology Department of Medicine University of British Columbia Vancouver Canada.,Division of Arrthythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Osaka Japan.,University of Rochester Medical Center Rochester USA.,Heart and Vascular Center Semmelweis University Budapest Hungary.,Department of Cardiology Austin Health Melbourne VIC Australia.,Cardiovascular Medicine University of Melbourne Melbourne VIC Australia.,Liverpool Centre for Cardiovascular Science University of Liverpool and Liverpool Heart & Chest Hospital Liverpool UK.,Aalborg Thrombosis Research Unit Department of Clinical Medicine Aalborg University Aalborg Denmark.,Department of Electrocardiology National Institute of Cardiology "Ignacio Chavez" Mexico City Mexico.,Division of Cardiology Department of Internal Medicine Yonsei University Health System Seoul Republic of Korea.,Department of Electrophysiology and Hemodynamic Arrhytmias Unity CMN 20 de Noviembre ISSSTE Mexico City Mexico.,Cardiovascular Division Brigham and Women's Hospital and Harvard Medical School Boston USA.,Department of Cardio Electrophysiology Fortis Escorts Heart Institute New Delhi India.,Department of Cardiology, Rigshospitalet University of Copenhagen Copenhagen Denmark.,Amsterdam UMC University of Amsterdam Heart Center Department of Clinical and Experimental Cardiology Amsterdam The Netherlands.,Hospital Militar Central Bogotá Colombia.,UCLA Cardiac Arrhythmia Center UCLA Health System David Geffen School of Medicine, at UCLA Los Angeles USA.,Heart Center Department of Clinical and Experimental Cardiology Amsterdam UMC University of Amsterdam Amsterdam The Netherlands.,Department of Medicine Intermountain Heart Institute Intermountain Medical Center Salt Lake City USA
| | - Gonzalo Calvimontes
- Department of Cardiology Aarhus University Hospital Skejby Denmark.,Division of Cardiology Department of Medicine Taipei Veterans General Hospital Taipei Taiwan.,Electrophysiology Service Department of Internal Medicine University of Campinas Hospital Campinas Brazil.,Department of Electrophysiology Leipzig Heart Center at University of Leipzig Leipzig Germany.,Division of Electrophysiology Instituto Cardiovascular Adventista Clinica Bazterrica Buenos Aires Argentina.,Department of Cardiology Clinique Pasteur Toulouse France.,Division of Electrophysiology Department of Cardiology Argerich Hospital and CEMIC Buenos Aires Argentina.,Department of Medicine University of Wisconsin-Madison Madison WI USA.,Division of Cardiology Virginia Commonwealth University School of Medicine Richmond USA.,Heart Institute University of São Paulo Medical School Arrhythmia Unit Instituto do Coração -InCor- Faculdade de Medicina de São Paulo São Paulo Brazil.,Faculty of Medicine Department of Cardiovascular Medicine Toho University Japan.,Department of Cardiac Electrophysiology Fortis Escorts Heart Institute New Delhi India.,The Heart and Vascular Research Center Metrohealth Campus of Case Western Reserve University Cleveland OH USA.,Division of Cardiology Department of Medicine University of British Columbia Vancouver Canada.,Division of Arrthythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Osaka Japan.,University of Rochester Medical Center Rochester USA.,Heart and Vascular Center Semmelweis University Budapest Hungary.,Department of Cardiology Austin Health Melbourne VIC Australia.,Cardiovascular Medicine University of Melbourne Melbourne VIC Australia.,Liverpool Centre for Cardiovascular Science University of Liverpool and Liverpool Heart & Chest Hospital Liverpool UK.,Aalborg Thrombosis Research Unit Department of Clinical Medicine Aalborg University Aalborg Denmark.,Department of Electrocardiology National Institute of Cardiology "Ignacio Chavez" Mexico City Mexico.,Division of Cardiology Department of Internal Medicine Yonsei University Health System Seoul Republic of Korea.,Department of Electrophysiology and Hemodynamic Arrhytmias Unity CMN 20 de Noviembre ISSSTE Mexico City Mexico.,Cardiovascular Division Brigham and Women's Hospital and Harvard Medical School Boston USA.,Department of Cardio Electrophysiology Fortis Escorts Heart Institute New Delhi India.,Department of Cardiology, Rigshospitalet University of Copenhagen Copenhagen Denmark.,Amsterdam UMC University of Amsterdam Heart Center Department of Clinical and Experimental Cardiology Amsterdam The Netherlands.,Hospital Militar Central Bogotá Colombia.,UCLA Cardiac Arrhythmia Center UCLA Health System David Geffen School of Medicine, at UCLA Los Angeles USA.,Heart Center Department of Clinical and Experimental Cardiology Amsterdam UMC University of Amsterdam Amsterdam The Netherlands.,Department of Medicine Intermountain Heart Institute Intermountain Medical Center Salt Lake City USA
| | - Tze-Fan Chao
- Department of Cardiology Aarhus University Hospital Skejby Denmark.,Division of Cardiology Department of Medicine Taipei Veterans General Hospital Taipei Taiwan.,Electrophysiology Service Department of Internal Medicine University of Campinas Hospital Campinas Brazil.,Department of Electrophysiology Leipzig Heart Center at University of Leipzig Leipzig Germany.,Division of Electrophysiology Instituto Cardiovascular Adventista Clinica Bazterrica Buenos Aires Argentina.,Department of Cardiology Clinique Pasteur Toulouse France.,Division of Electrophysiology Department of Cardiology Argerich Hospital and CEMIC Buenos Aires Argentina.,Department of Medicine University of Wisconsin-Madison Madison WI USA.,Division of Cardiology Virginia Commonwealth University School of Medicine Richmond USA.,Heart Institute University of São Paulo Medical School Arrhythmia Unit Instituto do Coração -InCor- Faculdade de Medicina de São Paulo São Paulo Brazil.,Faculty of Medicine Department of Cardiovascular Medicine Toho University Japan.,Department of Cardiac Electrophysiology Fortis Escorts Heart Institute New Delhi India.,The Heart and Vascular Research Center Metrohealth Campus of Case Western Reserve University Cleveland OH USA.,Division of Cardiology Department of Medicine University of British Columbia Vancouver Canada.,Division of Arrthythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Osaka Japan.,University of Rochester Medical Center Rochester USA.,Heart and Vascular Center Semmelweis University Budapest Hungary.,Department of Cardiology Austin Health Melbourne VIC Australia.,Cardiovascular Medicine University of Melbourne Melbourne VIC Australia.,Liverpool Centre for Cardiovascular Science University of Liverpool and Liverpool Heart & Chest Hospital Liverpool UK.,Aalborg Thrombosis Research Unit Department of Clinical Medicine Aalborg University Aalborg Denmark.,Department of Electrocardiology National Institute of Cardiology "Ignacio Chavez" Mexico City Mexico.,Division of Cardiology Department of Internal Medicine Yonsei University Health System Seoul Republic of Korea.,Department of Electrophysiology and Hemodynamic Arrhytmias Unity CMN 20 de Noviembre ISSSTE Mexico City Mexico.,Cardiovascular Division Brigham and Women's Hospital and Harvard Medical School Boston USA.,Department of Cardio Electrophysiology Fortis Escorts Heart Institute New Delhi India.,Department of Cardiology, Rigshospitalet University of Copenhagen Copenhagen Denmark.,Amsterdam UMC University of Amsterdam Heart Center Department of Clinical and Experimental Cardiology Amsterdam The Netherlands.,Hospital Militar Central Bogotá Colombia.,UCLA Cardiac Arrhythmia Center UCLA Health System David Geffen School of Medicine, at UCLA Los Angeles USA.,Heart Center Department of Clinical and Experimental Cardiology Amsterdam UMC University of Amsterdam Amsterdam The Netherlands.,Department of Medicine Intermountain Heart Institute Intermountain Medical Center Salt Lake City USA
| | - Lars Eckardt
- Department of Cardiology Aarhus University Hospital Skejby Denmark.,Division of Cardiology Department of Medicine Taipei Veterans General Hospital Taipei Taiwan.,Electrophysiology Service Department of Internal Medicine University of Campinas Hospital Campinas Brazil.,Department of Electrophysiology Leipzig Heart Center at University of Leipzig Leipzig Germany.,Division of Electrophysiology Instituto Cardiovascular Adventista Clinica Bazterrica Buenos Aires Argentina.,Department of Cardiology Clinique Pasteur Toulouse France.,Division of Electrophysiology Department of Cardiology Argerich Hospital and CEMIC Buenos Aires Argentina.,Department of Medicine University of Wisconsin-Madison Madison WI USA.,Division of Cardiology Virginia Commonwealth University School of Medicine Richmond USA.,Heart Institute University of São Paulo Medical School Arrhythmia Unit Instituto do Coração -InCor- Faculdade de Medicina de São Paulo São Paulo Brazil.,Faculty of Medicine Department of Cardiovascular Medicine Toho University Japan.,Department of Cardiac Electrophysiology Fortis Escorts Heart Institute New Delhi India.,The Heart and Vascular Research Center Metrohealth Campus of Case Western Reserve University Cleveland OH USA.,Division of Cardiology Department of Medicine University of British Columbia Vancouver Canada.,Division of Arrthythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Osaka Japan.,University of Rochester Medical Center Rochester USA.,Heart and Vascular Center Semmelweis University Budapest Hungary.,Department of Cardiology Austin Health Melbourne VIC Australia.,Cardiovascular Medicine University of Melbourne Melbourne VIC Australia.,Liverpool Centre for Cardiovascular Science University of Liverpool and Liverpool Heart & Chest Hospital Liverpool UK.,Aalborg Thrombosis Research Unit Department of Clinical Medicine Aalborg University Aalborg Denmark.,Department of Electrocardiology National Institute of Cardiology "Ignacio Chavez" Mexico City Mexico.,Division of Cardiology Department of Internal Medicine Yonsei University Health System Seoul Republic of Korea.,Department of Electrophysiology and Hemodynamic Arrhytmias Unity CMN 20 de Noviembre ISSSTE Mexico City Mexico.,Cardiovascular Division Brigham and Women's Hospital and Harvard Medical School Boston USA.,Department of Cardio Electrophysiology Fortis Escorts Heart Institute New Delhi India.,Department of Cardiology, Rigshospitalet University of Copenhagen Copenhagen Denmark.,Amsterdam UMC University of Amsterdam Heart Center Department of Clinical and Experimental Cardiology Amsterdam The Netherlands.,Hospital Militar Central Bogotá Colombia.,UCLA Cardiac Arrhythmia Center UCLA Health System David Geffen School of Medicine, at UCLA Los Angeles USA.,Heart Center Department of Clinical and Experimental Cardiology Amsterdam UMC University of Amsterdam Amsterdam The Netherlands.,Department of Medicine Intermountain Heart Institute Intermountain Medical Center Salt Lake City USA
| | - Heidi Estner
- Department of Cardiology Aarhus University Hospital Skejby Denmark.,Division of Cardiology Department of Medicine Taipei Veterans General Hospital Taipei Taiwan.,Electrophysiology Service Department of Internal Medicine University of Campinas Hospital Campinas Brazil.,Department of Electrophysiology Leipzig Heart Center at University of Leipzig Leipzig Germany.,Division of Electrophysiology Instituto Cardiovascular Adventista Clinica Bazterrica Buenos Aires Argentina.,Department of Cardiology Clinique Pasteur Toulouse France.,Division of Electrophysiology Department of Cardiology Argerich Hospital and CEMIC Buenos Aires Argentina.,Department of Medicine University of Wisconsin-Madison Madison WI USA.,Division of Cardiology Virginia Commonwealth University School of Medicine Richmond USA.,Heart Institute University of São Paulo Medical School Arrhythmia Unit Instituto do Coração -InCor- Faculdade de Medicina de São Paulo São Paulo Brazil.,Faculty of Medicine Department of Cardiovascular Medicine Toho University Japan.,Department of Cardiac Electrophysiology Fortis Escorts Heart Institute New Delhi India.,The Heart and Vascular Research Center Metrohealth Campus of Case Western Reserve University Cleveland OH USA.,Division of Cardiology Department of Medicine University of British Columbia Vancouver Canada.,Division of Arrthythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Osaka Japan.,University of Rochester Medical Center Rochester USA.,Heart and Vascular Center Semmelweis University Budapest Hungary.,Department of Cardiology Austin Health Melbourne VIC Australia.,Cardiovascular Medicine University of Melbourne Melbourne VIC Australia.,Liverpool Centre for Cardiovascular Science University of Liverpool and Liverpool Heart & Chest Hospital Liverpool UK.,Aalborg Thrombosis Research Unit Department of Clinical Medicine Aalborg University Aalborg Denmark.,Department of Electrocardiology National Institute of Cardiology "Ignacio Chavez" Mexico City Mexico.,Division of Cardiology Department of Internal Medicine Yonsei University Health System Seoul Republic of Korea.,Department of Electrophysiology and Hemodynamic Arrhytmias Unity CMN 20 de Noviembre ISSSTE Mexico City Mexico.,Cardiovascular Division Brigham and Women's Hospital and Harvard Medical School Boston USA.,Department of Cardio Electrophysiology Fortis Escorts Heart Institute New Delhi India.,Department of Cardiology, Rigshospitalet University of Copenhagen Copenhagen Denmark.,Amsterdam UMC University of Amsterdam Heart Center Department of Clinical and Experimental Cardiology Amsterdam The Netherlands.,Hospital Militar Central Bogotá Colombia.,UCLA Cardiac Arrhythmia Center UCLA Health System David Geffen School of Medicine, at UCLA Los Angeles USA.,Heart Center Department of Clinical and Experimental Cardiology Amsterdam UMC University of Amsterdam Amsterdam The Netherlands.,Department of Medicine Intermountain Heart Institute Intermountain Medical Center Salt Lake City USA
| | - Anne M Gillis
- Department of Cardiology Aarhus University Hospital Skejby Denmark.,Division of Cardiology Department of Medicine Taipei Veterans General Hospital Taipei Taiwan.,Electrophysiology Service Department of Internal Medicine University of Campinas Hospital Campinas Brazil.,Department of Electrophysiology Leipzig Heart Center at University of Leipzig Leipzig Germany.,Division of Electrophysiology Instituto Cardiovascular Adventista Clinica Bazterrica Buenos Aires Argentina.,Department of Cardiology Clinique Pasteur Toulouse France.,Division of Electrophysiology Department of Cardiology Argerich Hospital and CEMIC Buenos Aires Argentina.,Department of Medicine University of Wisconsin-Madison Madison WI USA.,Division of Cardiology Virginia Commonwealth University School of Medicine Richmond USA.,Heart Institute University of São Paulo Medical School Arrhythmia Unit Instituto do Coração -InCor- Faculdade de Medicina de São Paulo São Paulo Brazil.,Faculty of Medicine Department of Cardiovascular Medicine Toho University Japan.,Department of Cardiac Electrophysiology Fortis Escorts Heart Institute New Delhi India.,The Heart and Vascular Research Center Metrohealth Campus of Case Western Reserve University Cleveland OH USA.,Division of Cardiology Department of Medicine University of British Columbia Vancouver Canada.,Division of Arrthythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Osaka Japan.,University of Rochester Medical Center Rochester USA.,Heart and Vascular Center Semmelweis University Budapest Hungary.,Department of Cardiology Austin Health Melbourne VIC Australia.,Cardiovascular Medicine University of Melbourne Melbourne VIC Australia.,Liverpool Centre for Cardiovascular Science University of Liverpool and Liverpool Heart & Chest Hospital Liverpool UK.,Aalborg Thrombosis Research Unit Department of Clinical Medicine Aalborg University Aalborg Denmark.,Department of Electrocardiology National Institute of Cardiology "Ignacio Chavez" Mexico City Mexico.,Division of Cardiology Department of Internal Medicine Yonsei University Health System Seoul Republic of Korea.,Department of Electrophysiology and Hemodynamic Arrhytmias Unity CMN 20 de Noviembre ISSSTE Mexico City Mexico.,Cardiovascular Division Brigham and Women's Hospital and Harvard Medical School Boston USA.,Department of Cardio Electrophysiology Fortis Escorts Heart Institute New Delhi India.,Department of Cardiology, Rigshospitalet University of Copenhagen Copenhagen Denmark.,Amsterdam UMC University of Amsterdam Heart Center Department of Clinical and Experimental Cardiology Amsterdam The Netherlands.,Hospital Militar Central Bogotá Colombia.,UCLA Cardiac Arrhythmia Center UCLA Health System David Geffen School of Medicine, at UCLA Los Angeles USA.,Heart Center Department of Clinical and Experimental Cardiology Amsterdam UMC University of Amsterdam Amsterdam The Netherlands.,Department of Medicine Intermountain Heart Institute Intermountain Medical Center Salt Lake City USA
| | - Rodrigo Isa
- Department of Cardiology Aarhus University Hospital Skejby Denmark.,Division of Cardiology Department of Medicine Taipei Veterans General Hospital Taipei Taiwan.,Electrophysiology Service Department of Internal Medicine University of Campinas Hospital Campinas Brazil.,Department of Electrophysiology Leipzig Heart Center at University of Leipzig Leipzig Germany.,Division of Electrophysiology Instituto Cardiovascular Adventista Clinica Bazterrica Buenos Aires Argentina.,Department of Cardiology Clinique Pasteur Toulouse France.,Division of Electrophysiology Department of Cardiology Argerich Hospital and CEMIC Buenos Aires Argentina.,Department of Medicine University of Wisconsin-Madison Madison WI USA.,Division of Cardiology Virginia Commonwealth University School of Medicine Richmond USA.,Heart Institute University of São Paulo Medical School Arrhythmia Unit Instituto do Coração -InCor- Faculdade de Medicina de São Paulo São Paulo Brazil.,Faculty of Medicine Department of Cardiovascular Medicine Toho University Japan.,Department of Cardiac Electrophysiology Fortis Escorts Heart Institute New Delhi India.,The Heart and Vascular Research Center Metrohealth Campus of Case Western Reserve University Cleveland OH USA.,Division of Cardiology Department of Medicine University of British Columbia Vancouver Canada.,Division of Arrthythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Osaka Japan.,University of Rochester Medical Center Rochester USA.,Heart and Vascular Center Semmelweis University Budapest Hungary.,Department of Cardiology Austin Health Melbourne VIC Australia.,Cardiovascular Medicine University of Melbourne Melbourne VIC Australia.,Liverpool Centre for Cardiovascular Science University of Liverpool and Liverpool Heart & Chest Hospital Liverpool UK.,Aalborg Thrombosis Research Unit Department of Clinical Medicine Aalborg University Aalborg Denmark.,Department of Electrocardiology National Institute of Cardiology "Ignacio Chavez" Mexico City Mexico.,Division of Cardiology Department of Internal Medicine Yonsei University Health System Seoul Republic of Korea.,Department of Electrophysiology and Hemodynamic Arrhytmias Unity CMN 20 de Noviembre ISSSTE Mexico City Mexico.,Cardiovascular Division Brigham and Women's Hospital and Harvard Medical School Boston USA.,Department of Cardio Electrophysiology Fortis Escorts Heart Institute New Delhi India.,Department of Cardiology, Rigshospitalet University of Copenhagen Copenhagen Denmark.,Amsterdam UMC University of Amsterdam Heart Center Department of Clinical and Experimental Cardiology Amsterdam The Netherlands.,Hospital Militar Central Bogotá Colombia.,UCLA Cardiac Arrhythmia Center UCLA Health System David Geffen School of Medicine, at UCLA Los Angeles USA.,Heart Center Department of Clinical and Experimental Cardiology Amsterdam UMC University of Amsterdam Amsterdam The Netherlands.,Department of Medicine Intermountain Heart Institute Intermountain Medical Center Salt Lake City USA
| | - Josef Kautzner
- Department of Cardiology Aarhus University Hospital Skejby Denmark.,Division of Cardiology Department of Medicine Taipei Veterans General Hospital Taipei Taiwan.,Electrophysiology Service Department of Internal Medicine University of Campinas Hospital Campinas Brazil.,Department of Electrophysiology Leipzig Heart Center at University of Leipzig Leipzig Germany.,Division of Electrophysiology Instituto Cardiovascular Adventista Clinica Bazterrica Buenos Aires Argentina.,Department of Cardiology Clinique Pasteur Toulouse France.,Division of Electrophysiology Department of Cardiology Argerich Hospital and CEMIC Buenos Aires Argentina.,Department of Medicine University of Wisconsin-Madison Madison WI USA.,Division of Cardiology Virginia Commonwealth University School of Medicine Richmond USA.,Heart Institute University of São Paulo Medical School Arrhythmia Unit Instituto do Coração -InCor- Faculdade de Medicina de São Paulo São Paulo Brazil.,Faculty of Medicine Department of Cardiovascular Medicine Toho University Japan.,Department of Cardiac Electrophysiology Fortis Escorts Heart Institute New Delhi India.,The Heart and Vascular Research Center Metrohealth Campus of Case Western Reserve University Cleveland OH USA.,Division of Cardiology Department of Medicine University of British Columbia Vancouver Canada.,Division of Arrthythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Osaka Japan.,University of Rochester Medical Center Rochester USA.,Heart and Vascular Center Semmelweis University Budapest Hungary.,Department of Cardiology Austin Health Melbourne VIC Australia.,Cardiovascular Medicine University of Melbourne Melbourne VIC Australia.,Liverpool Centre for Cardiovascular Science University of Liverpool and Liverpool Heart & Chest Hospital Liverpool UK.,Aalborg Thrombosis Research Unit Department of Clinical Medicine Aalborg University Aalborg Denmark.,Department of Electrocardiology National Institute of Cardiology "Ignacio Chavez" Mexico City Mexico.,Division of Cardiology Department of Internal Medicine Yonsei University Health System Seoul Republic of Korea.,Department of Electrophysiology and Hemodynamic Arrhytmias Unity CMN 20 de Noviembre ISSSTE Mexico City Mexico.,Cardiovascular Division Brigham and Women's Hospital and Harvard Medical School Boston USA.,Department of Cardio Electrophysiology Fortis Escorts Heart Institute New Delhi India.,Department of Cardiology, Rigshospitalet University of Copenhagen Copenhagen Denmark.,Amsterdam UMC University of Amsterdam Heart Center Department of Clinical and Experimental Cardiology Amsterdam The Netherlands.,Hospital Militar Central Bogotá Colombia.,UCLA Cardiac Arrhythmia Center UCLA Health System David Geffen School of Medicine, at UCLA Los Angeles USA.,Heart Center Department of Clinical and Experimental Cardiology Amsterdam UMC University of Amsterdam Amsterdam The Netherlands.,Department of Medicine Intermountain Heart Institute Intermountain Medical Center Salt Lake City USA
| | - Philippe Maury
- Department of Cardiology Aarhus University Hospital Skejby Denmark.,Division of Cardiology Department of Medicine Taipei Veterans General Hospital Taipei Taiwan.,Electrophysiology Service Department of Internal Medicine University of Campinas Hospital Campinas Brazil.,Department of Electrophysiology Leipzig Heart Center at University of Leipzig Leipzig Germany.,Division of Electrophysiology Instituto Cardiovascular Adventista Clinica Bazterrica Buenos Aires Argentina.,Department of Cardiology Clinique Pasteur Toulouse France.,Division of Electrophysiology Department of Cardiology Argerich Hospital and CEMIC Buenos Aires Argentina.,Department of Medicine University of Wisconsin-Madison Madison WI USA.,Division of Cardiology Virginia Commonwealth University School of Medicine Richmond USA.,Heart Institute University of São Paulo Medical School Arrhythmia Unit Instituto do Coração -InCor- Faculdade de Medicina de São Paulo São Paulo Brazil.,Faculty of Medicine Department of Cardiovascular Medicine Toho University Japan.,Department of Cardiac Electrophysiology Fortis Escorts Heart Institute New Delhi India.,The Heart and Vascular Research Center Metrohealth Campus of Case Western Reserve University Cleveland OH USA.,Division of Cardiology Department of Medicine University of British Columbia Vancouver Canada.,Division of Arrthythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Osaka Japan.,University of Rochester Medical Center Rochester USA.,Heart and Vascular Center Semmelweis University Budapest Hungary.,Department of Cardiology Austin Health Melbourne VIC Australia.,Cardiovascular Medicine University of Melbourne Melbourne VIC Australia.,Liverpool Centre for Cardiovascular Science University of Liverpool and Liverpool Heart & Chest Hospital Liverpool UK.,Aalborg Thrombosis Research Unit Department of Clinical Medicine Aalborg University Aalborg Denmark.,Department of Electrocardiology National Institute of Cardiology "Ignacio Chavez" Mexico City Mexico.,Division of Cardiology Department of Internal Medicine Yonsei University Health System Seoul Republic of Korea.,Department of Electrophysiology and Hemodynamic Arrhytmias Unity CMN 20 de Noviembre ISSSTE Mexico City Mexico.,Cardiovascular Division Brigham and Women's Hospital and Harvard Medical School Boston USA.,Department of Cardio Electrophysiology Fortis Escorts Heart Institute New Delhi India.,Department of Cardiology, Rigshospitalet University of Copenhagen Copenhagen Denmark.,Amsterdam UMC University of Amsterdam Heart Center Department of Clinical and Experimental Cardiology Amsterdam The Netherlands.,Hospital Militar Central Bogotá Colombia.,UCLA Cardiac Arrhythmia Center UCLA Health System David Geffen School of Medicine, at UCLA Los Angeles USA.,Heart Center Department of Clinical and Experimental Cardiology Amsterdam UMC University of Amsterdam Amsterdam The Netherlands.,Department of Medicine Intermountain Heart Institute Intermountain Medical Center Salt Lake City USA
| | - Joshua D Moss
- Department of Cardiology Aarhus University Hospital Skejby Denmark.,Division of Cardiology Department of Medicine Taipei Veterans General Hospital Taipei Taiwan.,Electrophysiology Service Department of Internal Medicine University of Campinas Hospital Campinas Brazil.,Department of Electrophysiology Leipzig Heart Center at University of Leipzig Leipzig Germany.,Division of Electrophysiology Instituto Cardiovascular Adventista Clinica Bazterrica Buenos Aires Argentina.,Department of Cardiology Clinique Pasteur Toulouse France.,Division of Electrophysiology Department of Cardiology Argerich Hospital and CEMIC Buenos Aires Argentina.,Department of Medicine University of Wisconsin-Madison Madison WI USA.,Division of Cardiology Virginia Commonwealth University School of Medicine Richmond USA.,Heart Institute University of São Paulo Medical School Arrhythmia Unit Instituto do Coração -InCor- Faculdade de Medicina de São Paulo São Paulo Brazil.,Faculty of Medicine Department of Cardiovascular Medicine Toho University Japan.,Department of Cardiac Electrophysiology Fortis Escorts Heart Institute New Delhi India.,The Heart and Vascular Research Center Metrohealth Campus of Case Western Reserve University Cleveland OH USA.,Division of Cardiology Department of Medicine University of British Columbia Vancouver Canada.,Division of Arrthythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Osaka Japan.,University of Rochester Medical Center Rochester USA.,Heart and Vascular Center Semmelweis University Budapest Hungary.,Department of Cardiology Austin Health Melbourne VIC Australia.,Cardiovascular Medicine University of Melbourne Melbourne VIC Australia.,Liverpool Centre for Cardiovascular Science University of Liverpool and Liverpool Heart & Chest Hospital Liverpool UK.,Aalborg Thrombosis Research Unit Department of Clinical Medicine Aalborg University Aalborg Denmark.,Department of Electrocardiology National Institute of Cardiology "Ignacio Chavez" Mexico City Mexico.,Division of Cardiology Department of Internal Medicine Yonsei University Health System Seoul Republic of Korea.,Department of Electrophysiology and Hemodynamic Arrhytmias Unity CMN 20 de Noviembre ISSSTE Mexico City Mexico.,Cardiovascular Division Brigham and Women's Hospital and Harvard Medical School Boston USA.,Department of Cardio Electrophysiology Fortis Escorts Heart Institute New Delhi India.,Department of Cardiology, Rigshospitalet University of Copenhagen Copenhagen Denmark.,Amsterdam UMC University of Amsterdam Heart Center Department of Clinical and Experimental Cardiology Amsterdam The Netherlands.,Hospital Militar Central Bogotá Colombia.,UCLA Cardiac Arrhythmia Center UCLA Health System David Geffen School of Medicine, at UCLA Los Angeles USA.,Heart Center Department of Clinical and Experimental Cardiology Amsterdam UMC University of Amsterdam Amsterdam The Netherlands.,Department of Medicine Intermountain Heart Institute Intermountain Medical Center Salt Lake City USA
| | - Gi-Byung Nam
- Department of Cardiology Aarhus University Hospital Skejby Denmark.,Division of Cardiology Department of Medicine Taipei Veterans General Hospital Taipei Taiwan.,Electrophysiology Service Department of Internal Medicine University of Campinas Hospital Campinas Brazil.,Department of Electrophysiology Leipzig Heart Center at University of Leipzig Leipzig Germany.,Division of Electrophysiology Instituto Cardiovascular Adventista Clinica Bazterrica Buenos Aires Argentina.,Department of Cardiology Clinique Pasteur Toulouse France.,Division of Electrophysiology Department of Cardiology Argerich Hospital and CEMIC Buenos Aires Argentina.,Department of Medicine University of Wisconsin-Madison Madison WI USA.,Division of Cardiology Virginia Commonwealth University School of Medicine Richmond USA.,Heart Institute University of São Paulo Medical School Arrhythmia Unit Instituto do Coração -InCor- Faculdade de Medicina de São Paulo São Paulo Brazil.,Faculty of Medicine Department of Cardiovascular Medicine Toho University Japan.,Department of Cardiac Electrophysiology Fortis Escorts Heart Institute New Delhi India.,The Heart and Vascular Research Center Metrohealth Campus of Case Western Reserve University Cleveland OH USA.,Division of Cardiology Department of Medicine University of British Columbia Vancouver Canada.,Division of Arrthythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Osaka Japan.,University of Rochester Medical Center Rochester USA.,Heart and Vascular Center Semmelweis University Budapest Hungary.,Department of Cardiology Austin Health Melbourne VIC Australia.,Cardiovascular Medicine University of Melbourne Melbourne VIC Australia.,Liverpool Centre for Cardiovascular Science University of Liverpool and Liverpool Heart & Chest Hospital Liverpool UK.,Aalborg Thrombosis Research Unit Department of Clinical Medicine Aalborg University Aalborg Denmark.,Department of Electrocardiology National Institute of Cardiology "Ignacio Chavez" Mexico City Mexico.,Division of Cardiology Department of Internal Medicine Yonsei University Health System Seoul Republic of Korea.,Department of Electrophysiology and Hemodynamic Arrhytmias Unity CMN 20 de Noviembre ISSSTE Mexico City Mexico.,Cardiovascular Division Brigham and Women's Hospital and Harvard Medical School Boston USA.,Department of Cardio Electrophysiology Fortis Escorts Heart Institute New Delhi India.,Department of Cardiology, Rigshospitalet University of Copenhagen Copenhagen Denmark.,Amsterdam UMC University of Amsterdam Heart Center Department of Clinical and Experimental Cardiology Amsterdam The Netherlands.,Hospital Militar Central Bogotá Colombia.,UCLA Cardiac Arrhythmia Center UCLA Health System David Geffen School of Medicine, at UCLA Los Angeles USA.,Heart Center Department of Clinical and Experimental Cardiology Amsterdam UMC University of Amsterdam Amsterdam The Netherlands.,Department of Medicine Intermountain Heart Institute Intermountain Medical Center Salt Lake City USA
| | - Brian Olshansky
- Department of Cardiology Aarhus University Hospital Skejby Denmark.,Division of Cardiology Department of Medicine Taipei Veterans General Hospital Taipei Taiwan.,Electrophysiology Service Department of Internal Medicine University of Campinas Hospital Campinas Brazil.,Department of Electrophysiology Leipzig Heart Center at University of Leipzig Leipzig Germany.,Division of Electrophysiology Instituto Cardiovascular Adventista Clinica Bazterrica Buenos Aires Argentina.,Department of Cardiology Clinique Pasteur Toulouse France.,Division of Electrophysiology Department of Cardiology Argerich Hospital and CEMIC Buenos Aires Argentina.,Department of Medicine University of Wisconsin-Madison Madison WI USA.,Division of Cardiology Virginia Commonwealth University School of Medicine Richmond USA.,Heart Institute University of São Paulo Medical School Arrhythmia Unit Instituto do Coração -InCor- Faculdade de Medicina de São Paulo São Paulo Brazil.,Faculty of Medicine Department of Cardiovascular Medicine Toho University Japan.,Department of Cardiac Electrophysiology Fortis Escorts Heart Institute New Delhi India.,The Heart and Vascular Research Center Metrohealth Campus of Case Western Reserve University Cleveland OH USA.,Division of Cardiology Department of Medicine University of British Columbia Vancouver Canada.,Division of Arrthythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Osaka Japan.,University of Rochester Medical Center Rochester USA.,Heart and Vascular Center Semmelweis University Budapest Hungary.,Department of Cardiology Austin Health Melbourne VIC Australia.,Cardiovascular Medicine University of Melbourne Melbourne VIC Australia.,Liverpool Centre for Cardiovascular Science University of Liverpool and Liverpool Heart & Chest Hospital Liverpool UK.,Aalborg Thrombosis Research Unit Department of Clinical Medicine Aalborg University Aalborg Denmark.,Department of Electrocardiology National Institute of Cardiology "Ignacio Chavez" Mexico City Mexico.,Division of Cardiology Department of Internal Medicine Yonsei University Health System Seoul Republic of Korea.,Department of Electrophysiology and Hemodynamic Arrhytmias Unity CMN 20 de Noviembre ISSSTE Mexico City Mexico.,Cardiovascular Division Brigham and Women's Hospital and Harvard Medical School Boston USA.,Department of Cardio Electrophysiology Fortis Escorts Heart Institute New Delhi India.,Department of Cardiology, Rigshospitalet University of Copenhagen Copenhagen Denmark.,Amsterdam UMC University of Amsterdam Heart Center Department of Clinical and Experimental Cardiology Amsterdam The Netherlands.,Hospital Militar Central Bogotá Colombia.,UCLA Cardiac Arrhythmia Center UCLA Health System David Geffen School of Medicine, at UCLA Los Angeles USA.,Heart Center Department of Clinical and Experimental Cardiology Amsterdam UMC University of Amsterdam Amsterdam The Netherlands.,Department of Medicine Intermountain Heart Institute Intermountain Medical Center Salt Lake City USA
| | - Luis Fernando Pava Molano
- Department of Cardiology Aarhus University Hospital Skejby Denmark.,Division of Cardiology Department of Medicine Taipei Veterans General Hospital Taipei Taiwan.,Electrophysiology Service Department of Internal Medicine University of Campinas Hospital Campinas Brazil.,Department of Electrophysiology Leipzig Heart Center at University of Leipzig Leipzig Germany.,Division of Electrophysiology Instituto Cardiovascular Adventista Clinica Bazterrica Buenos Aires Argentina.,Department of Cardiology Clinique Pasteur Toulouse France.,Division of Electrophysiology Department of Cardiology Argerich Hospital and CEMIC Buenos Aires Argentina.,Department of Medicine University of Wisconsin-Madison Madison WI USA.,Division of Cardiology Virginia Commonwealth University School of Medicine Richmond USA.,Heart Institute University of São Paulo Medical School Arrhythmia Unit Instituto do Coração -InCor- Faculdade de Medicina de São Paulo São Paulo Brazil.,Faculty of Medicine Department of Cardiovascular Medicine Toho University Japan.,Department of Cardiac Electrophysiology Fortis Escorts Heart Institute New Delhi India.,The Heart and Vascular Research Center Metrohealth Campus of Case Western Reserve University Cleveland OH USA.,Division of Cardiology Department of Medicine University of British Columbia Vancouver Canada.,Division of Arrthythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Osaka Japan.,University of Rochester Medical Center Rochester USA.,Heart and Vascular Center Semmelweis University Budapest Hungary.,Department of Cardiology Austin Health Melbourne VIC Australia.,Cardiovascular Medicine University of Melbourne Melbourne VIC Australia.,Liverpool Centre for Cardiovascular Science University of Liverpool and Liverpool Heart & Chest Hospital Liverpool UK.,Aalborg Thrombosis Research Unit Department of Clinical Medicine Aalborg University Aalborg Denmark.,Department of Electrocardiology National Institute of Cardiology "Ignacio Chavez" Mexico City Mexico.,Division of Cardiology Department of Internal Medicine Yonsei University Health System Seoul Republic of Korea.,Department of Electrophysiology and Hemodynamic Arrhytmias Unity CMN 20 de Noviembre ISSSTE Mexico City Mexico.,Cardiovascular Division Brigham and Women's Hospital and Harvard Medical School Boston USA.,Department of Cardio Electrophysiology Fortis Escorts Heart Institute New Delhi India.,Department of Cardiology, Rigshospitalet University of Copenhagen Copenhagen Denmark.,Amsterdam UMC University of Amsterdam Heart Center Department of Clinical and Experimental Cardiology Amsterdam The Netherlands.,Hospital Militar Central Bogotá Colombia.,UCLA Cardiac Arrhythmia Center UCLA Health System David Geffen School of Medicine, at UCLA Los Angeles USA.,Heart Center Department of Clinical and Experimental Cardiology Amsterdam UMC University of Amsterdam Amsterdam The Netherlands.,Department of Medicine Intermountain Heart Institute Intermountain Medical Center Salt Lake City USA
| | - Mauricio Pimentel
- Department of Cardiology Aarhus University Hospital Skejby Denmark.,Division of Cardiology Department of Medicine Taipei Veterans General Hospital Taipei Taiwan.,Electrophysiology Service Department of Internal Medicine University of Campinas Hospital Campinas Brazil.,Department of Electrophysiology Leipzig Heart Center at University of Leipzig Leipzig Germany.,Division of Electrophysiology Instituto Cardiovascular Adventista Clinica Bazterrica Buenos Aires Argentina.,Department of Cardiology Clinique Pasteur Toulouse France.,Division of Electrophysiology Department of Cardiology Argerich Hospital and CEMIC Buenos Aires Argentina.,Department of Medicine University of Wisconsin-Madison Madison WI USA.,Division of Cardiology Virginia Commonwealth University School of Medicine Richmond USA.,Heart Institute University of São Paulo Medical School Arrhythmia Unit Instituto do Coração -InCor- Faculdade de Medicina de São Paulo São Paulo Brazil.,Faculty of Medicine Department of Cardiovascular Medicine Toho University Japan.,Department of Cardiac Electrophysiology Fortis Escorts Heart Institute New Delhi India.,The Heart and Vascular Research Center Metrohealth Campus of Case Western Reserve University Cleveland OH USA.,Division of Cardiology Department of Medicine University of British Columbia Vancouver Canada.,Division of Arrthythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Osaka Japan.,University of Rochester Medical Center Rochester USA.,Heart and Vascular Center Semmelweis University Budapest Hungary.,Department of Cardiology Austin Health Melbourne VIC Australia.,Cardiovascular Medicine University of Melbourne Melbourne VIC Australia.,Liverpool Centre for Cardiovascular Science University of Liverpool and Liverpool Heart & Chest Hospital Liverpool UK.,Aalborg Thrombosis Research Unit Department of Clinical Medicine Aalborg University Aalborg Denmark.,Department of Electrocardiology National Institute of Cardiology "Ignacio Chavez" Mexico City Mexico.,Division of Cardiology Department of Internal Medicine Yonsei University Health System Seoul Republic of Korea.,Department of Electrophysiology and Hemodynamic Arrhytmias Unity CMN 20 de Noviembre ISSSTE Mexico City Mexico.,Cardiovascular Division Brigham and Women's Hospital and Harvard Medical School Boston USA.,Department of Cardio Electrophysiology Fortis Escorts Heart Institute New Delhi India.,Department of Cardiology, Rigshospitalet University of Copenhagen Copenhagen Denmark.,Amsterdam UMC University of Amsterdam Heart Center Department of Clinical and Experimental Cardiology Amsterdam The Netherlands.,Hospital Militar Central Bogotá Colombia.,UCLA Cardiac Arrhythmia Center UCLA Health System David Geffen School of Medicine, at UCLA Los Angeles USA.,Heart Center Department of Clinical and Experimental Cardiology Amsterdam UMC University of Amsterdam Amsterdam The Netherlands.,Department of Medicine Intermountain Heart Institute Intermountain Medical Center Salt Lake City USA
| | - Mukund Prabhu
- Department of Cardiology Aarhus University Hospital Skejby Denmark.,Division of Cardiology Department of Medicine Taipei Veterans General Hospital Taipei Taiwan.,Electrophysiology Service Department of Internal Medicine University of Campinas Hospital Campinas Brazil.,Department of Electrophysiology Leipzig Heart Center at University of Leipzig Leipzig Germany.,Division of Electrophysiology Instituto Cardiovascular Adventista Clinica Bazterrica Buenos Aires Argentina.,Department of Cardiology Clinique Pasteur Toulouse France.,Division of Electrophysiology Department of Cardiology Argerich Hospital and CEMIC Buenos Aires Argentina.,Department of Medicine University of Wisconsin-Madison Madison WI USA.,Division of Cardiology Virginia Commonwealth University School of Medicine Richmond USA.,Heart Institute University of São Paulo Medical School Arrhythmia Unit Instituto do Coração -InCor- Faculdade de Medicina de São Paulo São Paulo Brazil.,Faculty of Medicine Department of Cardiovascular Medicine Toho University Japan.,Department of Cardiac Electrophysiology Fortis Escorts Heart Institute New Delhi India.,The Heart and Vascular Research Center Metrohealth Campus of Case Western Reserve University Cleveland OH USA.,Division of Cardiology Department of Medicine University of British Columbia Vancouver Canada.,Division of Arrthythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Osaka Japan.,University of Rochester Medical Center Rochester USA.,Heart and Vascular Center Semmelweis University Budapest Hungary.,Department of Cardiology Austin Health Melbourne VIC Australia.,Cardiovascular Medicine University of Melbourne Melbourne VIC Australia.,Liverpool Centre for Cardiovascular Science University of Liverpool and Liverpool Heart & Chest Hospital Liverpool UK.,Aalborg Thrombosis Research Unit Department of Clinical Medicine Aalborg University Aalborg Denmark.,Department of Electrocardiology National Institute of Cardiology "Ignacio Chavez" Mexico City Mexico.,Division of Cardiology Department of Internal Medicine Yonsei University Health System Seoul Republic of Korea.,Department of Electrophysiology and Hemodynamic Arrhytmias Unity CMN 20 de Noviembre ISSSTE Mexico City Mexico.,Cardiovascular Division Brigham and Women's Hospital and Harvard Medical School Boston USA.,Department of Cardio Electrophysiology Fortis Escorts Heart Institute New Delhi India.,Department of Cardiology, Rigshospitalet University of Copenhagen Copenhagen Denmark.,Amsterdam UMC University of Amsterdam Heart Center Department of Clinical and Experimental Cardiology Amsterdam The Netherlands.,Hospital Militar Central Bogotá Colombia.,UCLA Cardiac Arrhythmia Center UCLA Health System David Geffen School of Medicine, at UCLA Los Angeles USA.,Heart Center Department of Clinical and Experimental Cardiology Amsterdam UMC University of Amsterdam Amsterdam The Netherlands.,Department of Medicine Intermountain Heart Institute Intermountain Medical Center Salt Lake City USA
| | - Wendy S Tzou
- Department of Cardiology Aarhus University Hospital Skejby Denmark.,Division of Cardiology Department of Medicine Taipei Veterans General Hospital Taipei Taiwan.,Electrophysiology Service Department of Internal Medicine University of Campinas Hospital Campinas Brazil.,Department of Electrophysiology Leipzig Heart Center at University of Leipzig Leipzig Germany.,Division of Electrophysiology Instituto Cardiovascular Adventista Clinica Bazterrica Buenos Aires Argentina.,Department of Cardiology Clinique Pasteur Toulouse France.,Division of Electrophysiology Department of Cardiology Argerich Hospital and CEMIC Buenos Aires Argentina.,Department of Medicine University of Wisconsin-Madison Madison WI USA.,Division of Cardiology Virginia Commonwealth University School of Medicine Richmond USA.,Heart Institute University of São Paulo Medical School Arrhythmia Unit Instituto do Coração -InCor- Faculdade de Medicina de São Paulo São Paulo Brazil.,Faculty of Medicine Department of Cardiovascular Medicine Toho University Japan.,Department of Cardiac Electrophysiology Fortis Escorts Heart Institute New Delhi India.,The Heart and Vascular Research Center Metrohealth Campus of Case Western Reserve University Cleveland OH USA.,Division of Cardiology Department of Medicine University of British Columbia Vancouver Canada.,Division of Arrthythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Osaka Japan.,University of Rochester Medical Center Rochester USA.,Heart and Vascular Center Semmelweis University Budapest Hungary.,Department of Cardiology Austin Health Melbourne VIC Australia.,Cardiovascular Medicine University of Melbourne Melbourne VIC Australia.,Liverpool Centre for Cardiovascular Science University of Liverpool and Liverpool Heart & Chest Hospital Liverpool UK.,Aalborg Thrombosis Research Unit Department of Clinical Medicine Aalborg University Aalborg Denmark.,Department of Electrocardiology National Institute of Cardiology "Ignacio Chavez" Mexico City Mexico.,Division of Cardiology Department of Internal Medicine Yonsei University Health System Seoul Republic of Korea.,Department of Electrophysiology and Hemodynamic Arrhytmias Unity CMN 20 de Noviembre ISSSTE Mexico City Mexico.,Cardiovascular Division Brigham and Women's Hospital and Harvard Medical School Boston USA.,Department of Cardio Electrophysiology Fortis Escorts Heart Institute New Delhi India.,Department of Cardiology, Rigshospitalet University of Copenhagen Copenhagen Denmark.,Amsterdam UMC University of Amsterdam Heart Center Department of Clinical and Experimental Cardiology Amsterdam The Netherlands.,Hospital Militar Central Bogotá Colombia.,UCLA Cardiac Arrhythmia Center UCLA Health System David Geffen School of Medicine, at UCLA Los Angeles USA.,Heart Center Department of Clinical and Experimental Cardiology Amsterdam UMC University of Amsterdam Amsterdam The Netherlands.,Department of Medicine Intermountain Heart Institute Intermountain Medical Center Salt Lake City USA
| | - Philipp Sommer
- Department of Cardiology Aarhus University Hospital Skejby Denmark.,Division of Cardiology Department of Medicine Taipei Veterans General Hospital Taipei Taiwan.,Electrophysiology Service Department of Internal Medicine University of Campinas Hospital Campinas Brazil.,Department of Electrophysiology Leipzig Heart Center at University of Leipzig Leipzig Germany.,Division of Electrophysiology Instituto Cardiovascular Adventista Clinica Bazterrica Buenos Aires Argentina.,Department of Cardiology Clinique Pasteur Toulouse France.,Division of Electrophysiology Department of Cardiology Argerich Hospital and CEMIC Buenos Aires Argentina.,Department of Medicine University of Wisconsin-Madison Madison WI USA.,Division of Cardiology Virginia Commonwealth University School of Medicine Richmond USA.,Heart Institute University of São Paulo Medical School Arrhythmia Unit Instituto do Coração -InCor- Faculdade de Medicina de São Paulo São Paulo Brazil.,Faculty of Medicine Department of Cardiovascular Medicine Toho University Japan.,Department of Cardiac Electrophysiology Fortis Escorts Heart Institute New Delhi India.,The Heart and Vascular Research Center Metrohealth Campus of Case Western Reserve University Cleveland OH USA.,Division of Cardiology Department of Medicine University of British Columbia Vancouver Canada.,Division of Arrthythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Osaka Japan.,University of Rochester Medical Center Rochester USA.,Heart and Vascular Center Semmelweis University Budapest Hungary.,Department of Cardiology Austin Health Melbourne VIC Australia.,Cardiovascular Medicine University of Melbourne Melbourne VIC Australia.,Liverpool Centre for Cardiovascular Science University of Liverpool and Liverpool Heart & Chest Hospital Liverpool UK.,Aalborg Thrombosis Research Unit Department of Clinical Medicine Aalborg University Aalborg Denmark.,Department of Electrocardiology National Institute of Cardiology "Ignacio Chavez" Mexico City Mexico.,Division of Cardiology Department of Internal Medicine Yonsei University Health System Seoul Republic of Korea.,Department of Electrophysiology and Hemodynamic Arrhytmias Unity CMN 20 de Noviembre ISSSTE Mexico City Mexico.,Cardiovascular Division Brigham and Women's Hospital and Harvard Medical School Boston USA.,Department of Cardio Electrophysiology Fortis Escorts Heart Institute New Delhi India.,Department of Cardiology, Rigshospitalet University of Copenhagen Copenhagen Denmark.,Amsterdam UMC University of Amsterdam Heart Center Department of Clinical and Experimental Cardiology Amsterdam The Netherlands.,Hospital Militar Central Bogotá Colombia.,UCLA Cardiac Arrhythmia Center UCLA Health System David Geffen School of Medicine, at UCLA Los Angeles USA.,Heart Center Department of Clinical and Experimental Cardiology Amsterdam UMC University of Amsterdam Amsterdam The Netherlands.,Department of Medicine Intermountain Heart Institute Intermountain Medical Center Salt Lake City USA
| | - Janice Swampillai
- Department of Cardiology Aarhus University Hospital Skejby Denmark.,Division of Cardiology Department of Medicine Taipei Veterans General Hospital Taipei Taiwan.,Electrophysiology Service Department of Internal Medicine University of Campinas Hospital Campinas Brazil.,Department of Electrophysiology Leipzig Heart Center at University of Leipzig Leipzig Germany.,Division of Electrophysiology Instituto Cardiovascular Adventista Clinica Bazterrica Buenos Aires Argentina.,Department of Cardiology Clinique Pasteur Toulouse France.,Division of Electrophysiology Department of Cardiology Argerich Hospital and CEMIC Buenos Aires Argentina.,Department of Medicine University of Wisconsin-Madison Madison WI USA.,Division of Cardiology Virginia Commonwealth University School of Medicine Richmond USA.,Heart Institute University of São Paulo Medical School Arrhythmia Unit Instituto do Coração -InCor- Faculdade de Medicina de São Paulo São Paulo Brazil.,Faculty of Medicine Department of Cardiovascular Medicine Toho University Japan.,Department of Cardiac Electrophysiology Fortis Escorts Heart Institute New Delhi India.,The Heart and Vascular Research Center Metrohealth Campus of Case Western Reserve University Cleveland OH USA.,Division of Cardiology Department of Medicine University of British Columbia Vancouver Canada.,Division of Arrthythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Osaka Japan.,University of Rochester Medical Center Rochester USA.,Heart and Vascular Center Semmelweis University Budapest Hungary.,Department of Cardiology Austin Health Melbourne VIC Australia.,Cardiovascular Medicine University of Melbourne Melbourne VIC Australia.,Liverpool Centre for Cardiovascular Science University of Liverpool and Liverpool Heart & Chest Hospital Liverpool UK.,Aalborg Thrombosis Research Unit Department of Clinical Medicine Aalborg University Aalborg Denmark.,Department of Electrocardiology National Institute of Cardiology "Ignacio Chavez" Mexico City Mexico.,Division of Cardiology Department of Internal Medicine Yonsei University Health System Seoul Republic of Korea.,Department of Electrophysiology and Hemodynamic Arrhytmias Unity CMN 20 de Noviembre ISSSTE Mexico City Mexico.,Cardiovascular Division Brigham and Women's Hospital and Harvard Medical School Boston USA.,Department of Cardio Electrophysiology Fortis Escorts Heart Institute New Delhi India.,Department of Cardiology, Rigshospitalet University of Copenhagen Copenhagen Denmark.,Amsterdam UMC University of Amsterdam Heart Center Department of Clinical and Experimental Cardiology Amsterdam The Netherlands.,Hospital Militar Central Bogotá Colombia.,UCLA Cardiac Arrhythmia Center UCLA Health System David Geffen School of Medicine, at UCLA Los Angeles USA.,Heart Center Department of Clinical and Experimental Cardiology Amsterdam UMC University of Amsterdam Amsterdam The Netherlands.,Department of Medicine Intermountain Heart Institute Intermountain Medical Center Salt Lake City USA
| | - Alejandro Vidal
- Department of Cardiology Aarhus University Hospital Skejby Denmark.,Division of Cardiology Department of Medicine Taipei Veterans General Hospital Taipei Taiwan.,Electrophysiology Service Department of Internal Medicine University of Campinas Hospital Campinas Brazil.,Department of Electrophysiology Leipzig Heart Center at University of Leipzig Leipzig Germany.,Division of Electrophysiology Instituto Cardiovascular Adventista Clinica Bazterrica Buenos Aires Argentina.,Department of Cardiology Clinique Pasteur Toulouse France.,Division of Electrophysiology Department of Cardiology Argerich Hospital and CEMIC Buenos Aires Argentina.,Department of Medicine University of Wisconsin-Madison Madison WI USA.,Division of Cardiology Virginia Commonwealth University School of Medicine Richmond USA.,Heart Institute University of São Paulo Medical School Arrhythmia Unit Instituto do Coração -InCor- Faculdade de Medicina de São Paulo São Paulo Brazil.,Faculty of Medicine Department of Cardiovascular Medicine Toho University Japan.,Department of Cardiac Electrophysiology Fortis Escorts Heart Institute New Delhi India.,The Heart and Vascular Research Center Metrohealth Campus of Case Western Reserve University Cleveland OH USA.,Division of Cardiology Department of Medicine University of British Columbia Vancouver Canada.,Division of Arrthythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Osaka Japan.,University of Rochester Medical Center Rochester USA.,Heart and Vascular Center Semmelweis University Budapest Hungary.,Department of Cardiology Austin Health Melbourne VIC Australia.,Cardiovascular Medicine University of Melbourne Melbourne VIC Australia.,Liverpool Centre for Cardiovascular Science University of Liverpool and Liverpool Heart & Chest Hospital Liverpool UK.,Aalborg Thrombosis Research Unit Department of Clinical Medicine Aalborg University Aalborg Denmark.,Department of Electrocardiology National Institute of Cardiology "Ignacio Chavez" Mexico City Mexico.,Division of Cardiology Department of Internal Medicine Yonsei University Health System Seoul Republic of Korea.,Department of Electrophysiology and Hemodynamic Arrhytmias Unity CMN 20 de Noviembre ISSSTE Mexico City Mexico.,Cardiovascular Division Brigham and Women's Hospital and Harvard Medical School Boston USA.,Department of Cardio Electrophysiology Fortis Escorts Heart Institute New Delhi India.,Department of Cardiology, Rigshospitalet University of Copenhagen Copenhagen Denmark.,Amsterdam UMC University of Amsterdam Heart Center Department of Clinical and Experimental Cardiology Amsterdam The Netherlands.,Hospital Militar Central Bogotá Colombia.,UCLA Cardiac Arrhythmia Center UCLA Health System David Geffen School of Medicine, at UCLA Los Angeles USA.,Heart Center Department of Clinical and Experimental Cardiology Amsterdam UMC University of Amsterdam Amsterdam The Netherlands.,Department of Medicine Intermountain Heart Institute Intermountain Medical Center Salt Lake City USA
| | - Thomas Deneke
- Department of Cardiology Aarhus University Hospital Skejby Denmark.,Division of Cardiology Department of Medicine Taipei Veterans General Hospital Taipei Taiwan.,Electrophysiology Service Department of Internal Medicine University of Campinas Hospital Campinas Brazil.,Department of Electrophysiology Leipzig Heart Center at University of Leipzig Leipzig Germany.,Division of Electrophysiology Instituto Cardiovascular Adventista Clinica Bazterrica Buenos Aires Argentina.,Department of Cardiology Clinique Pasteur Toulouse France.,Division of Electrophysiology Department of Cardiology Argerich Hospital and CEMIC Buenos Aires Argentina.,Department of Medicine University of Wisconsin-Madison Madison WI USA.,Division of Cardiology Virginia Commonwealth University School of Medicine Richmond USA.,Heart Institute University of São Paulo Medical School Arrhythmia Unit Instituto do Coração -InCor- Faculdade de Medicina de São Paulo São Paulo Brazil.,Faculty of Medicine Department of Cardiovascular Medicine Toho University Japan.,Department of Cardiac Electrophysiology Fortis Escorts Heart Institute New Delhi India.,The Heart and Vascular Research Center Metrohealth Campus of Case Western Reserve University Cleveland OH USA.,Division of Cardiology Department of Medicine University of British Columbia Vancouver Canada.,Division of Arrthythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Osaka Japan.,University of Rochester Medical Center Rochester USA.,Heart and Vascular Center Semmelweis University Budapest Hungary.,Department of Cardiology Austin Health Melbourne VIC Australia.,Cardiovascular Medicine University of Melbourne Melbourne VIC Australia.,Liverpool Centre for Cardiovascular Science University of Liverpool and Liverpool Heart & Chest Hospital Liverpool UK.,Aalborg Thrombosis Research Unit Department of Clinical Medicine Aalborg University Aalborg Denmark.,Department of Electrocardiology National Institute of Cardiology "Ignacio Chavez" Mexico City Mexico.,Division of Cardiology Department of Internal Medicine Yonsei University Health System Seoul Republic of Korea.,Department of Electrophysiology and Hemodynamic Arrhytmias Unity CMN 20 de Noviembre ISSSTE Mexico City Mexico.,Cardiovascular Division Brigham and Women's Hospital and Harvard Medical School Boston USA.,Department of Cardio Electrophysiology Fortis Escorts Heart Institute New Delhi India.,Department of Cardiology, Rigshospitalet University of Copenhagen Copenhagen Denmark.,Amsterdam UMC University of Amsterdam Heart Center Department of Clinical and Experimental Cardiology Amsterdam The Netherlands.,Hospital Militar Central Bogotá Colombia.,UCLA Cardiac Arrhythmia Center UCLA Health System David Geffen School of Medicine, at UCLA Los Angeles USA.,Heart Center Department of Clinical and Experimental Cardiology Amsterdam UMC University of Amsterdam Amsterdam The Netherlands.,Department of Medicine Intermountain Heart Institute Intermountain Medical Center Salt Lake City USA
| | - Gerhard Hindricks
- Department of Cardiology Aarhus University Hospital Skejby Denmark.,Division of Cardiology Department of Medicine Taipei Veterans General Hospital Taipei Taiwan.,Electrophysiology Service Department of Internal Medicine University of Campinas Hospital Campinas Brazil.,Department of Electrophysiology Leipzig Heart Center at University of Leipzig Leipzig Germany.,Division of Electrophysiology Instituto Cardiovascular Adventista Clinica Bazterrica Buenos Aires Argentina.,Department of Cardiology Clinique Pasteur Toulouse France.,Division of Electrophysiology Department of Cardiology Argerich Hospital and CEMIC Buenos Aires Argentina.,Department of Medicine University of Wisconsin-Madison Madison WI USA.,Division of Cardiology Virginia Commonwealth University School of Medicine Richmond USA.,Heart Institute University of São Paulo Medical School Arrhythmia Unit Instituto do Coração -InCor- Faculdade de Medicina de São Paulo São Paulo Brazil.,Faculty of Medicine Department of Cardiovascular Medicine Toho University Japan.,Department of Cardiac Electrophysiology Fortis Escorts Heart Institute New Delhi India.,The Heart and Vascular Research Center Metrohealth Campus of Case Western Reserve University Cleveland OH USA.,Division of Cardiology Department of Medicine University of British Columbia Vancouver Canada.,Division of Arrthythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Osaka Japan.,University of Rochester Medical Center Rochester USA.,Heart and Vascular Center Semmelweis University Budapest Hungary.,Department of Cardiology Austin Health Melbourne VIC Australia.,Cardiovascular Medicine University of Melbourne Melbourne VIC Australia.,Liverpool Centre for Cardiovascular Science University of Liverpool and Liverpool Heart & Chest Hospital Liverpool UK.,Aalborg Thrombosis Research Unit Department of Clinical Medicine Aalborg University Aalborg Denmark.,Department of Electrocardiology National Institute of Cardiology "Ignacio Chavez" Mexico City Mexico.,Division of Cardiology Department of Internal Medicine Yonsei University Health System Seoul Republic of Korea.,Department of Electrophysiology and Hemodynamic Arrhytmias Unity CMN 20 de Noviembre ISSSTE Mexico City Mexico.,Cardiovascular Division Brigham and Women's Hospital and Harvard Medical School Boston USA.,Department of Cardio Electrophysiology Fortis Escorts Heart Institute New Delhi India.,Department of Cardiology, Rigshospitalet University of Copenhagen Copenhagen Denmark.,Amsterdam UMC University of Amsterdam Heart Center Department of Clinical and Experimental Cardiology Amsterdam The Netherlands.,Hospital Militar Central Bogotá Colombia.,UCLA Cardiac Arrhythmia Center UCLA Health System David Geffen School of Medicine, at UCLA Los Angeles USA.,Heart Center Department of Clinical and Experimental Cardiology Amsterdam UMC University of Amsterdam Amsterdam The Netherlands.,Department of Medicine Intermountain Heart Institute Intermountain Medical Center Salt Lake City USA
| | - Christophe Leclercq
- Department of Cardiology Aarhus University Hospital Skejby Denmark.,Division of Cardiology Department of Medicine Taipei Veterans General Hospital Taipei Taiwan.,Electrophysiology Service Department of Internal Medicine University of Campinas Hospital Campinas Brazil.,Department of Electrophysiology Leipzig Heart Center at University of Leipzig Leipzig Germany.,Division of Electrophysiology Instituto Cardiovascular Adventista Clinica Bazterrica Buenos Aires Argentina.,Department of Cardiology Clinique Pasteur Toulouse France.,Division of Electrophysiology Department of Cardiology Argerich Hospital and CEMIC Buenos Aires Argentina.,Department of Medicine University of Wisconsin-Madison Madison WI USA.,Division of Cardiology Virginia Commonwealth University School of Medicine Richmond USA.,Heart Institute University of São Paulo Medical School Arrhythmia Unit Instituto do Coração -InCor- Faculdade de Medicina de São Paulo São Paulo Brazil.,Faculty of Medicine Department of Cardiovascular Medicine Toho University Japan.,Department of Cardiac Electrophysiology Fortis Escorts Heart Institute New Delhi India.,The Heart and Vascular Research Center Metrohealth Campus of Case Western Reserve University Cleveland OH USA.,Division of Cardiology Department of Medicine University of British Columbia Vancouver Canada.,Division of Arrthythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Osaka Japan.,University of Rochester Medical Center Rochester USA.,Heart and Vascular Center Semmelweis University Budapest Hungary.,Department of Cardiology Austin Health Melbourne VIC Australia.,Cardiovascular Medicine University of Melbourne Melbourne VIC Australia.,Liverpool Centre for Cardiovascular Science University of Liverpool and Liverpool Heart & Chest Hospital Liverpool UK.,Aalborg Thrombosis Research Unit Department of Clinical Medicine Aalborg University Aalborg Denmark.,Department of Electrocardiology National Institute of Cardiology "Ignacio Chavez" Mexico City Mexico.,Division of Cardiology Department of Internal Medicine Yonsei University Health System Seoul Republic of Korea.,Department of Electrophysiology and Hemodynamic Arrhytmias Unity CMN 20 de Noviembre ISSSTE Mexico City Mexico.,Cardiovascular Division Brigham and Women's Hospital and Harvard Medical School Boston USA.,Department of Cardio Electrophysiology Fortis Escorts Heart Institute New Delhi India.,Department of Cardiology, Rigshospitalet University of Copenhagen Copenhagen Denmark.,Amsterdam UMC University of Amsterdam Heart Center Department of Clinical and Experimental Cardiology Amsterdam The Netherlands.,Hospital Militar Central Bogotá Colombia.,UCLA Cardiac Arrhythmia Center UCLA Health System David Geffen School of Medicine, at UCLA Los Angeles USA.,Heart Center Department of Clinical and Experimental Cardiology Amsterdam UMC University of Amsterdam Amsterdam The Netherlands.,Department of Medicine Intermountain Heart Institute Intermountain Medical Center Salt Lake City USA
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13
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Trovato C, Passini E, Nagy N, Varró A, Abi-Gerges N, Severi S, Rodriguez B. Human Purkinje in silico model enables mechanistic investigations into automaticity and pro-arrhythmic abnormalities. J Mol Cell Cardiol 2020; 142:24-38. [PMID: 32251669 PMCID: PMC7294239 DOI: 10.1016/j.yjmcc.2020.04.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 03/30/2020] [Accepted: 04/01/2020] [Indexed: 02/06/2023]
Abstract
Cardiac Purkinje cells (PCs) are implicated in lethal arrhythmias caused by cardiac diseases, mutations, and drug action. However, the pro-arrhythmic mechanisms in PCs are not entirely understood, particularly in humans, as most investigations are conducted in animals. The aims of this study are to present a novel human PCs electrophysiology biophysically-detailed computational model, and to disentangle ionic mechanisms of human Purkinje-related electrophysiology, pacemaker activity and arrhythmogenicity. The new Trovato2020 model incorporates detailed Purkinje-specific ionic currents and Ca2+ handling, and was developed, calibrated and validated using human experimental data acquired at multiple frequencies, both in control conditions and following drug application. Multiscale investigations were performed in a Purkinje cell, in fibre and using an experimentally-calibrated population of PCs to evaluate biological variability. Simulations demonstrate the human Purkinje Trovato2020 model is the first one to yield: (i) all key AP features consistent with human Purkinje recordings; (ii) Automaticity with funny current up-regulation (iii) EADs at slow pacing and with 85% hERG block; (iv) DADs following fast pacing; (v) conduction velocity of 160 cm/s in a Purkinje fibre, as reported in human. The human in silico PCs population highlights that: (1) EADs are caused by ICaL reactivation in PCs with large inward currents; (2) DADs and triggered APs occur in PCs experiencing Ca2+ accumulation, at fast pacing, caused by large L-type calcium current and small Na+/Ca2+ exchanger. The novel human Purkinje model unlocks further investigations into the role of cardiac Purkinje in ventricular arrhythmias through computer modeling and multiscale simulations.
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Affiliation(s)
- Cristian Trovato
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford OX13QD, United Kingdom.
| | - Elisa Passini
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford OX13QD, United Kingdom
| | - Norbert Nagy
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged H-6720, Hungary; Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary
| | - András Varró
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged H-6720, Hungary; Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary
| | - Najah Abi-Gerges
- AnaBios Corporation, San Diego Science Center, San Diego, CA 92109, USA
| | - Stefano Severi
- Department of Electrical, Electronic and Information Engineering, University of Bologna, Cesena 47521, Italy
| | - Blanca Rodriguez
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford OX13QD, United Kingdom.
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14
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Kistamás K, Veress R, Horváth B, Bányász T, Nánási PP, Eisner DA. Calcium Handling Defects and Cardiac Arrhythmia Syndromes. Front Pharmacol 2020; 11:72. [PMID: 32161540 PMCID: PMC7052815 DOI: 10.3389/fphar.2020.00072] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 01/24/2020] [Indexed: 12/13/2022] Open
Abstract
Calcium ions (Ca2+) play a major role in the cardiac excitation-contraction coupling. Intracellular Ca2+ concentration increases during systole and falls in diastole thereby determining cardiac contraction and relaxation. Normal cardiac function also requires perfect organization of the ion currents at the cellular level to drive action potentials and to maintain action potential propagation and electrical homogeneity at the tissue level. Any imbalance in Ca2+ homeostasis of a cardiac myocyte can lead to electrical disturbances. This review aims to discuss cardiac physiology and pathophysiology from the elementary membrane processes that can cause the electrical instability of the ventricular myocytes through intracellular Ca2+ handling maladies to inherited and acquired arrhythmias. Finally, the paper will discuss the current therapeutic approaches targeting cardiac arrhythmias.
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Affiliation(s)
- Kornél Kistamás
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,Division of Cardiovascular Sciences, School of Medical Sciences, University of Manchester, Manchester, United Kingdom
| | - Roland Veress
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Balázs Horváth
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Tamás Bányász
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Péter P Nánási
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,Department of Dental Physiology, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary
| | - David A Eisner
- Division of Cardiovascular Sciences, School of Medical Sciences, University of Manchester, Manchester, United Kingdom
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15
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Xing C, Jin Q, Zhang N, Liu S, Lin C, Wu Q, Luo Q, Liu A, Wu L. Effect of flunarizine on defibrillation outcomes and early refibrillation in a canine model of prolonged ventricular fibrillation. Exp Physiol 2019; 104:1630-1637. [PMID: 31465138 PMCID: PMC6899960 DOI: 10.1113/ep087068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 08/23/2019] [Indexed: 11/20/2022]
Abstract
New Findings What is the central question of this study? Can successful electrical shock in combination with a delayed after‐depolarization (DAD) blocker suppress early refibrillation episodes following long duration ventricular fibrillation (LDVF)? What is the main finding and its importance? Flunarizine significantly reduced the activation of LDVF and early ventricular fibrillation (VF) recurrence following LDVF, suggesting that DADs potentially contribute to refibrillation in prolonged VF. Thus, DAD inhibition can be used as an adjunctive therapy for electrical defibrillation to treat prolonged VF and suppress refibrillation following LDVF.
Abstract This study attempts to detect changes in the defibrillation threshold (DFT) at different stages of ventricular fibrillation (VF) (short duration VF, SDVF; long duration VF, LDVF) and during early refibrillation following successful defibrillation of LDVF by giving flunarizine, a blocker of delayed after‐depolarizations (DADs). Twelve beagles were divided into two groups (the control group, n = 6; and the flunarizine group, n = 6). Two 64‐electrode basket catheters were deployed into the left and the right ventricles for global endocardium mapping. The DFTs of SDVF and LDVF were determined at 20 s and 7 min, respectively, after VF induction in each group. Any refibrillation episodes were recorded within 15 min after the first successful defibrillation of LDVF. In the flunarizine group, the SDVF‐DFT values before and after the drug were not significantly different. The 7 min LDVF‐DFTs were markedly reduced by 26% (P < 0.05, the control group) and 38% (P < 0.01, the flunarizine group) compared to the 20 s SDVF‐DFTs within each group. The difference between SDVF‐DFT and LDVF‐DFT after flunarizine was larger than that in the control group (213 ± 65 vs. 120 ± 84 V, P < 0.05). The number of refibrillation episodes per animal (1.3 ± 1.0) following successful defibrillation of LDVF after flunarizine was 48% of that in controls (2.7 ± 2.0, P < 0.05). The effect of flunarizine on SDVF‐DFT and LDVF‐DFT indicates that the role of DADs in the defibrillation mechanism may differ as VF continues. Flunarizine significantly reduced early VF recurrence following LDVF, suggesting that DADs potentially contribute to refibrillation in a canine model of prolonged VF.
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Affiliation(s)
- Chaofan Xing
- Department of Cardiology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qi Jin
- Department of Cardiology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ning Zhang
- Department of Cardiology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shaohua Liu
- Department of Cardiology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Changjian Lin
- Department of Cardiology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qiong Wu
- Department of Cardiology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qingzhi Luo
- Department of Cardiology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ao Liu
- Department of Cardiology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Liqun Wu
- Department of Cardiology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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16
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Arkles JS, Marchlinski FE. Anchoring in a storm: The importance of substrate in polymorphic ventricular arrhythmias. Heart Rhythm 2019; 16:1028-1029. [PMID: 30794880 DOI: 10.1016/j.hrthm.2019.02.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Indexed: 12/01/2022]
Affiliation(s)
- Jeffrey S Arkles
- Cardiac Electrophysiology Program, Cardiovascular Division, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Francis E Marchlinski
- Cardiac Electrophysiology Program, Cardiovascular Division, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania.
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17
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Kamada R, Yokoshiki H, Mitsuyama H, Watanabe M, Mizukami K, Tenma T, Takahashi M, Takada S, Anzai T. Arrhythmogenic β-adrenergic signaling in cardiac hypertrophy: The role of small-conductance calcium-activated potassium channels via activation of CaMKII. Eur J Pharmacol 2019; 844:110-117. [DOI: 10.1016/j.ejphar.2018.12.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 11/29/2018] [Accepted: 12/06/2018] [Indexed: 10/27/2022]
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18
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Prajapati C, Pölönen RP, Aalto-Setälä K. Simultaneous recordings of action potentials and calcium transients from human induced pluripotent stem cell derived cardiomyocytes. Biol Open 2018; 7:bio.035030. [PMID: 29970475 PMCID: PMC6078349 DOI: 10.1242/bio.035030] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs) offer a unique in vitro platform to study cardiac diseases, as they recapitulate many disease phenotypes. The membrane potential (Vm) and intracellular calcium (Ca2+) transient (CaT) are usually investigated separately, because incorporating different techniques to acquire both aspects concurrently is challenging. In this study, we recorded Vm and CaT simultaneously to understand the interrelation between these parameters in hiPSC-CMs. For this, we used a conventional patch clamp technique to record Vm, and synchronized this with a Ca2+ imaging system to acquire CaT from same hiPSC-CMs. Our results revealed that the CaT at 90% decay (CaT90) was longer than action potential (AP) duration at 90% repolarization (APD90). In addition, there was also a strong positive correlation between the different parameters of CaT and AP. The majority of delayed after depolarizations (DADs) observed in the Vm recording were also characterized by elevations in the intracellular Ca2+ level, but in some cases no abnormalities were observed in CaT. However, simultaneous fluctuations in CaT were always observed during early after depolarizations (EADs) in Vm In summary, simultaneous recording of Vm and CaT broadens the understanding of the interrelation between Vm and CaT and could be used to elucidate the mechanisms underlying arrhythmia in cardiac disease condition.
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Affiliation(s)
| | | | - Katriina Aalto-Setälä
- BioMediTech, University of Tampere, 33520 Tampere, Finland .,Faculty of Medicine and Life Science, University of Tampere, 33520 Tampere, Finland.,Heart Hospital, Tampere University Hospital, 33520 Tampere, Finland
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19
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Song Z, Liu MB, Qu Z. Transverse tubular network structures in the genesis of intracellular calcium alternans and triggered activity in cardiac cells. J Mol Cell Cardiol 2018; 114:288-299. [PMID: 29217432 PMCID: PMC5801147 DOI: 10.1016/j.yjmcc.2017.12.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 10/31/2017] [Accepted: 12/04/2017] [Indexed: 12/20/2022]
Abstract
RATIONALE The major role of a transverse-tubular (TT) network in a cardiac cell is to facilitate effective excitation-contraction coupling and signaling. The TT network structures are heterogeneous within a single cell, and vary between different types of cells and species. They are also remodeled in cardiac diseases. However, how different TT network structures predispose cardiac cells to arrhythmogenesis remains to be revealed. OBJECTIVE To systematically investigate the roles of TT network structure and the underlying mechanisms in the genesis of intracellular calcium (Ca2+) alternans and triggered activity (TA). METHODS AND RESULTS Based on recent experimental observations, different TT network structures, including uniformly and non-uniformly random TT distributions, were modeled in a cardiac cell model consisting of a three-dimensional network of Ca2+ release units (CRUs). Our simulations showed that both Ca2+ alternans and Ca2+ wave-mediated TA were promoted when the fraction of orphaned CRUs was in an intermediate range, but suppressed in cells exhibiting either well-organized TT networks or low TT densities. Ca2+ alternans and TA could be promoted by low TT densities when the cells were small or the CRU coupling was strong. Both alternans and TA occurred more easily in uniformly random TT networks than in non-uniformly random TT networks. Subcellular spatially discordant Ca2+ alternans was promoted by non-uniformly random TT networks but suppressed by increasing CRU coupling strength. These mechanistic insights provide a holistic understanding of the effects of TT network structure on the susceptibility to arrhythmogenesis. CONCLUSIONS The TT network plays important roles in promoting Ca2+ alternans and TA, and different TT network structures may predispose cardiac cells differently to arrhythmogenesis.
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Affiliation(s)
- Zhen Song
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.
| | - Michael B Liu
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - Zhilin Qu
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA; Department of Biomathematics, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.
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20
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Walker MA, Gurev V, Rice JJ, Greenstein JL, Winslow RL. Estimating the probabilities of rare arrhythmic events in multiscale computational models of cardiac cells and tissue. PLoS Comput Biol 2017; 13:e1005783. [PMID: 29145393 PMCID: PMC5689829 DOI: 10.1371/journal.pcbi.1005783] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 09/18/2017] [Indexed: 11/24/2022] Open
Abstract
Ectopic heartbeats can trigger reentrant arrhythmias, leading to ventricular fibrillation and sudden cardiac death. Such events have been attributed to perturbed Ca2+ handling in cardiac myocytes leading to spontaneous Ca2+ release and delayed afterdepolarizations (DADs). However, the ways in which perturbation of specific molecular mechanisms alters the probability of ectopic beats is not understood. We present a multiscale model of cardiac tissue incorporating a biophysically detailed three-dimensional model of the ventricular myocyte. This model reproduces realistic Ca2+ waves and DADs driven by stochastic Ca2+ release channel (RyR) gating and is used to study mechanisms of DAD variability. In agreement with previous experimental and modeling studies, key factors influencing the distribution of DAD amplitude and timing include cytosolic and sarcoplasmic reticulum Ca2+ concentrations, inwardly rectifying potassium current (IK1) density, and gap junction conductance. The cardiac tissue model is used to investigate how random RyR gating gives rise to probabilistic triggered activity in a one-dimensional myocyte tissue model. A novel spatial-average filtering method for estimating the probability of extreme (i.e. rare, high-amplitude) stochastic events from a limited set of spontaneous Ca2+ release profiles is presented. These events occur when randomly organized clusters of cells exhibit synchronized, high amplitude Ca2+ release flux. It is shown how reduced IK1 density and gap junction coupling, as observed in heart failure, increase the probability of extreme DADs by multiple orders of magnitude. This method enables prediction of arrhythmia likelihood and its modulation by alterations of other cellular mechanisms.
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Affiliation(s)
- Mark A. Walker
- Department of Biomedical Engineering and Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, United States of America
| | - Viatcheslav Gurev
- TJ Watson Research Center, IBM, Yorktown Heights, NY, United States of America
| | - John J. Rice
- TJ Watson Research Center, IBM, Yorktown Heights, NY, United States of America
| | - Joseph L. Greenstein
- Department of Biomedical Engineering and Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, United States of America
| | - Raimond L. Winslow
- Department of Biomedical Engineering and Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, United States of America
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21
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Ko CY, Liu MB, Song Z, Qu Z, Weiss JN. Multiscale Determinants of Delayed Afterdepolarization Amplitude in Cardiac Tissue. Biophys J 2017; 112:1949-1961. [PMID: 28494965 DOI: 10.1016/j.bpj.2017.03.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 03/02/2017] [Accepted: 03/06/2017] [Indexed: 11/17/2022] Open
Abstract
Spontaneous calcium (Ca) waves in cardiac myocytes underlie delayed afterdepolarizations (DADs) that trigger cardiac arrhythmias. How these subcellular/cellular events overcome source-sink factors in cardiac tissue to generate DADs of sufficient amplitude to trigger action potentials is not fully understood. Here, we evaluate quantitatively how factors at the subcellular scale (number of Ca wave initiation sites), cellular scale (sarcoplasmic reticulum (SR) Ca load), and tissue scale (synchrony of Ca release in populations of myocytes) determine DAD features in cardiac tissue using a combined experimental and computational modeling approach. Isolated patch-clamped rabbit ventricular myocytes loaded with Fluo-4 to image intracellular Ca were rapidly paced during exposure to elevated extracellular Ca (2.7 mmol/L) and isoproterenol (0.25 μmol/L) to induce diastolic Ca waves and subthreshold DADs. As the number of paced beats increased from 1 to 5, SR Ca content (assessed with caffeine pulses) increased, the number of Ca wave initiation sites increased, integrated Ca transients and DADs became larger and shorter in duration, and the latency period to the onset of Ca waves shortened with reduced variance. In silico analysis using a computer model of ventricular tissue incorporating these experimental measurements revealed that whereas all of these factors promoted larger DADs with higher probability of generating triggered activity, the latency period variance and SR Ca load had the greatest influences. Therefore, incorporating quantitative experimental data into tissue level simulations reveals that increased intracellular Ca promotes DAD-mediated triggered activity in tissue predominantly by increasing both the synchrony (decreasing latency variance) of Ca waves in nearby myocytes and SR Ca load, whereas the number of Ca wave initiation sites per myocyte is less important.
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Affiliation(s)
- Christopher Y Ko
- Division of Cardiology, Department of Medicine, UCLA Cardiovascular Research Laboratory, University of California, Los Angeles, California
| | - Michael B Liu
- Division of Cardiology, Department of Medicine, UCLA Cardiovascular Research Laboratory, University of California, Los Angeles, California
| | - Zhen Song
- Division of Cardiology, Department of Medicine, UCLA Cardiovascular Research Laboratory, University of California, Los Angeles, California
| | - Zhilin Qu
- Division of Cardiology, Department of Medicine, UCLA Cardiovascular Research Laboratory, University of California, Los Angeles, California; Department of Biomathematics, David Geffen School of Medicine, University of California, Los Angeles, California
| | - James N Weiss
- Division of Cardiology, Department of Medicine, UCLA Cardiovascular Research Laboratory, University of California, Los Angeles, California; Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, California.
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22
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Reher TA, Wang Z, Hsueh CH, Chang PC, Pan Z, Kumar M, Patel J, Tan J, Shen C, Chen Z, Fishbein MC, Rubart M, Boyden P, Chen PS. Small-Conductance Calcium-Activated Potassium Current in Normal Rabbit Cardiac Purkinje Cells. J Am Heart Assoc 2017; 6:JAHA.117.005471. [PMID: 28550095 PMCID: PMC5669169 DOI: 10.1161/jaha.117.005471] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Background Purkinje cells (PCs) are important in cardiac arrhythmogenesis. Whether small‐conductance calcium‐activated potassium (SK) channels are present in PCs remains unclear. We tested the hypotheses that subtype 2 SK (SK2) channel proteins and apamin‐sensitive SK currents are abundantly present in PCs. Methods and Results We studied 25 normal rabbit ventricles, including 13 patch‐clamp studies, 4 for Western blotting, and 8 for immunohistochemical staining. Transmembrane action potentials were recorded in current‐clamp mode using the perforated‐patch technique. For PCs, the apamin (100 nmol/L) significantly prolonged action potential duration measured to 80% repolarization by an average of 10.4 ms (95% CI, 0.11–20.72) (n=9, P=0.047). Voltage‐clamp study showed that apamin‐sensitive SK current density was significantly larger in PCs compared with ventricular myocytes at potentials ≥0 mV. Western blotting of SK2 expression showed that the SK2 protein expression in the midmyocardium was 58% (P=0.028) and the epicardium was 50% (P=0.018) of that in the pseudotendons. Immunostaining of SK2 protein showed that PCs stained stronger than ventricular myocytes. Confocal microscope study showed SK2 protein was distributed to the periphery of the PCs. Conclusions SK2 proteins are more abundantly present in the PCs than in the ventricular myocytes of normal rabbit ventricles. Apamin‐sensitive SK current is important in ventricular repolarization of normal PCs.
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Affiliation(s)
- Thomas A Reher
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indianapolis, IN
| | - Zhuo Wang
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indianapolis, IN.,Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Chia-Hsiang Hsueh
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indianapolis, IN
| | - Po-Cheng Chang
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indianapolis, IN
| | - Zhenwei Pan
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indianapolis, IN
| | - Mohineesh Kumar
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indianapolis, IN
| | - Jheel Patel
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indianapolis, IN
| | - Jian Tan
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indianapolis, IN
| | - Changyu Shen
- Smith Center for Outcomes Research in Cardiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Zhenhui Chen
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indianapolis, IN
| | - Michael C Fishbein
- Department of Pathology and Laboratory Medicine, UCLA Medical Center, Los Angeles, CA
| | - Michael Rubart
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN
| | - Penelope Boyden
- Department of Pharmacology, Columbia University, New York, NY
| | - Peng-Sheng Chen
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indianapolis, IN
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Exclusion of alternative exon 33 of Ca V1.2 calcium channels in heart is proarrhythmogenic. Proc Natl Acad Sci U S A 2017; 114:E4288-E4295. [PMID: 28490495 DOI: 10.1073/pnas.1617205114] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Alternative splicing changes the CaV1.2 calcium channel electrophysiological property, but the in vivo significance of such altered channel function is lacking. Structure-function studies of heterologously expressed CaV1.2 channels could not recapitulate channel function in the native milieu of the cardiomyocyte. To address this gap in knowledge, we investigated the role of alternative exon 33 of the CaV1.2 calcium channel in heart function. Exclusion of exon 33 in CaV1.2 channels has been reported to shift the activation potential -10.4 mV to the hyperpolarized direction, and increased expression of CaV1.2Δ33 channels was observed in rat myocardial infarcted hearts. However, how a change in CaV1.2 channel electrophysiological property, due to alternative splicing, might affect cardiac function in vivo is unknown. To address these questions, we generated mCacna1c exon 33-/--null mice. These mice contained CaV1.2Δ33 channels with a gain-of-function that included conduction of larger currents that reflects a shift in voltage dependence and a modest increase in single-channel open probability. This altered channel property underscored the development of ventricular arrhythmia, which is reflected in significantly more deaths of exon 33-/- mice from β-adrenergic stimulation. In vivo telemetric recordings also confirmed increased frequencies in premature ventricular contractions, tachycardia, and lengthened QT interval. Taken together, the significant decrease or absence of exon 33-containing CaV1.2 channels is potentially proarrhythmic in the heart. Of clinical relevance, human ischemic and dilated cardiomyopathy hearts showed increased inclusion of exon 33. However, the possible role that inclusion of exon 33 in CaV1.2 channels may play in the pathogenesis of human heart failure remains unclear.
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Britton OJ, Bueno-Orovio A, Virág L, Varró A, Rodriguez B. The Electrogenic Na +/K + Pump Is a Key Determinant of Repolarization Abnormality Susceptibility in Human Ventricular Cardiomyocytes: A Population-Based Simulation Study. Front Physiol 2017; 8:278. [PMID: 28529489 PMCID: PMC5418229 DOI: 10.3389/fphys.2017.00278] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 04/18/2017] [Indexed: 11/23/2022] Open
Abstract
Background: Cellular repolarization abnormalities occur unpredictably due to disease and drug effects, and can occur even in cardiomyocytes that exhibit normal action potentials (AP) under control conditions. Variability in ion channel densities may explain differences in this susceptibility to repolarization abnormalities. Here, we quantify the importance of key ionic mechanisms determining repolarization abnormalities following ionic block in human cardiomyocytes yielding normal APs under control conditions. Methods and Results: Sixty two AP recordings from non-diseased human heart preparations were used to construct a population of human ventricular models with normal APs and a wide range of ion channel densities. Multichannel ionic block was applied to investigate susceptibility to repolarization abnormalities. IKr block was necessary for the development of repolarization abnormalities. Models that developed repolarization abnormalities over the widest range of blocks possessed low Na+/K+ pump conductance below 50% of baseline, and ICaL conductance above 70% of baseline. Furthermore, INaK made the second largest contribution to repolarizing current in control simulations and the largest contribution under 75% IKr block. Reversing intracellular Na+ overload caused by reduced INaK was not sufficient to prevent abnormalities in models with low Na+/K+ pump conductance, while returning Na+/K+ pump conductance to normal substantially reduced abnormality occurrence, indicating INaK is an important repolarization current. Conclusions: INaK is an important determinant of repolarization abnormality susceptibility in human ventricular cardiomyocytes, through its contribution to repolarization current rather than homeostasis. While we found IKr block to be necessary for repolarization abnormalities to occur, INaK decrease, as in disease, may amplify the pro-arrhythmic risk of drug-induced IKr block in humans.
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Affiliation(s)
| | | | - László Virág
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of SzegedSzeged, Hungary
| | - András Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of SzegedSzeged, Hungary
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Liu MB, Ko CY, Song Z, Garfinkel A, Weiss JN, Qu Z. A Dynamical Threshold for Cardiac Delayed Afterdepolarization-Mediated Triggered Activity. Biophys J 2016; 111:2523-2533. [PMID: 27926853 PMCID: PMC5153551 DOI: 10.1016/j.bpj.2016.10.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 09/22/2016] [Accepted: 10/11/2016] [Indexed: 11/18/2022] Open
Abstract
Ventricular myocytes are excitable cells whose voltage threshold for action potential (AP) excitation is ∼-60 mV at which INa is activated to give rise to a fast upstroke. Therefore, for a short stimulus pulse to elicit an AP, a stronger stimulus is needed if the resting potential lies further away from the INa threshold, such as in hypokalemia. However, for an AP elicited by a long duration stimulus or a diastolic spontaneous calcium release, we observed that the stimulus needed was lower in hypokalemia than in normokalemia in both computer simulations and experiments of rabbit ventricular myocytes. This observation provides insight into why hypokalemia promotes calcium-mediated triggered activity, despite the resting potential lying further away from the INa threshold. To understand the underlying mechanisms, we performed bifurcation analyses and demonstrated that there is a dynamical threshold, resulting from a saddle-node bifurcation mainly determined by IK1 and INCX. This threshold is close to the voltage at which IK1 is maximum, and lower than the INa threshold. After exceeding this dynamical threshold, the membrane voltage will automatically depolarize above the INa threshold due to the large negative slope of the IK1-V curve. This dynamical threshold becomes much lower in hypokalemia, especially with respect to calcium, as predicted by our theory. Because of the saddle-node bifurcation, the system can automatically depolarize even in the absence of INa to voltages higher than the ICa,L threshold, allowing for triggered APs in single myocytes with complete INa block. However, because INa is important for AP propagation in tissue, blocking INa can still suppress premature ventricular excitations in cardiac tissue caused by calcium-mediated triggered activity. This suppression is more effective in normokalemia than in hypokalemia due to the difference in dynamical thresholds.
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Affiliation(s)
- Michael B Liu
- Cardiovascular Research Laboratory, University of California, Los Angeles, Los Angeles, California; Department of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Christopher Y Ko
- Cardiovascular Research Laboratory, University of California, Los Angeles, Los Angeles, California; Department of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Zhen Song
- Cardiovascular Research Laboratory, University of California, Los Angeles, Los Angeles, California; Department of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Alan Garfinkel
- Cardiovascular Research Laboratory, University of California, Los Angeles, Los Angeles, California; Department of Medicine, University of California, Los Angeles, Los Angeles, California; Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, California
| | - James N Weiss
- Cardiovascular Research Laboratory, University of California, Los Angeles, Los Angeles, California; Department of Medicine, University of California, Los Angeles, Los Angeles, California; Department of Physiology, University of California, Los Angeles, Los Angeles, California
| | - Zhilin Qu
- Cardiovascular Research Laboratory, University of California, Los Angeles, Los Angeles, California; Department of Medicine, University of California, Los Angeles, Los Angeles, California; Department of Biomathematics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California.
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26
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Song Z, Ko CY, Nivala M, Weiss JN, Qu Z. Calcium-voltage coupling in the genesis of early and delayed afterdepolarizations in cardiac myocytes. Biophys J 2016; 108:1908-21. [PMID: 25902431 DOI: 10.1016/j.bpj.2015.03.011] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 03/04/2015] [Accepted: 03/10/2015] [Indexed: 02/01/2023] Open
Abstract
Early afterdepolarizations (EADs) and delayed afterdepolarizations (DADs) are voltage oscillations known to cause cardiac arrhythmias. EADs are mainly driven by voltage oscillations in the repolarizing phase of the action potential (AP), while DADs are driven by spontaneous calcium (Ca) release during diastole. Because voltage and Ca are bidirectionally coupled, they modulate each other's behaviors, and new AP and Ca cycling dynamics can emerge from this coupling. In this study, we performed computer simulations using an AP model with detailed spatiotemporal Ca cycling incorporating stochastic openings of Ca channels and ryanodine receptors to investigate the effects of Ca-voltage coupling on EAD and DAD dynamics. Simulations were complemented by experiments in mouse ventricular myocytes. We show that: 1) alteration of the Ca transient due to increased ryanodine receptor leakiness and/or sarco/endoplasmic reticulum Ca ATPase activity can either promote or suppress EADs due to the complex effects of Ca on ionic current properties; 2) spontaneous Ca waves also exhibit complex effects on EADs, but cannot induce EADs of significant amplitude without the participation of ICa,L; 3) lengthening AP duration and the occurrence of EADs promote DADs by increasing intracellular Ca loading, and two mechanisms of DADs are identified, i.e., Ca-wave-dependent and Ca-wave-independent; and 4) Ca-voltage coupling promotes complex EAD patterns such as EAD alternans that are not observed for solely voltage-driven EADs. In conclusion, Ca-voltage coupling combined with the nonlinear dynamical behaviors of voltage and Ca cycling play a key role in generating complex EAD and DAD dynamics observed experimentally in cardiac myocytes, whose mechanisms are complex but analyzable.
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Affiliation(s)
- Zhen Song
- Cardiovascular Research Laboratory, University of California, Los Angeles, California; Department of Medicine (Cardiology), University of California, Los Angeles, California
| | - Christopher Y Ko
- Cardiovascular Research Laboratory, University of California, Los Angeles, California; Department of Medicine (Cardiology), University of California, Los Angeles, California
| | - Michael Nivala
- Cardiovascular Research Laboratory, University of California, Los Angeles, California; Department of Medicine (Cardiology), University of California, Los Angeles, California
| | - James N Weiss
- Cardiovascular Research Laboratory, University of California, Los Angeles, California; Department of Medicine (Cardiology), University of California, Los Angeles, California; Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, California
| | - Zhilin Qu
- Cardiovascular Research Laboratory, University of California, Los Angeles, California; Department of Medicine (Cardiology), University of California, Los Angeles, California.
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28
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Liu MB, de Lange E, Garfinkel A, Weiss JN, Qu Z. Delayed afterdepolarizations generate both triggers and a vulnerable substrate promoting reentry in cardiac tissue. Heart Rhythm 2015; 12:2115-24. [PMID: 26072025 PMCID: PMC4583816 DOI: 10.1016/j.hrthm.2015.06.019] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Indexed: 11/23/2022]
Abstract
BACKGROUND Delayed afterdepolarizations (DADs) have been well characterized as arrhythmia triggers, but their role in generating a tissue substrate vulnerable to reentry is not well understood. OBJECTIVE The purpose of this study was to test the hypothesis that random DADs can self-organize to generate both an arrhythmia trigger and a vulnerable substrate simultaneously in cardiac tissue as a result of gap junction coupling. METHODS Computer simulations in 1-dimensional cable and 2-dimensional tissue models were performed. The cellular DAD amplitude was varied by changing the strength of sarcoplasmic reticulum calcium release. Random DAD latency and amplitude in different cells were simulated using gaussian distributions. RESULTS Depending on the strength of spontaneous sarcoplasmic reticulum calcium release and other conditions, random DADs in cardiac tissue resulted in the following behaviors: (1) triggered activity (TA); (2) a vulnerable tissue substrate causing unidirectional conduction block and reentry by inactivating sodium channels; (3) both triggers and a vulnerable substrate simultaneously by generating TA in regions next to regions with subthreshold DADs susceptible to unidirectional conduction block and reentry. The probability of the latter 2 behaviors was enhanced by reduced sodium channel availability, reduced gap junction coupling, increased tissue heterogeneity, and less synchronous DAD latency. CONCLUSION DADs can self-organize in tissue to generate arrhythmia triggers, a vulnerable tissue substrate, and both simultaneously. Reduced sodium channel availability and gap junction coupling potentiate this mechanism of arrhythmias, which are relevant to a variety of heart disease conditions.
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Affiliation(s)
- Michael B Liu
- UCLA Cardiovascular Research Laboratory; Department of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los Angeles, California
| | - Enno de Lange
- UCLA Cardiovascular Research Laboratory; Department of Knowledge Engineering, Maastricht University, Maastricht, The Netherlands
| | - Alan Garfinkel
- UCLA Cardiovascular Research Laboratory; Department of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los Angeles, California; Department of Integrative Biology and Physiology, University of California, Los Angeles, California
| | - James N Weiss
- UCLA Cardiovascular Research Laboratory; Department of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los Angeles, California; Department of Integrative Biology and Physiology, University of California, Los Angeles, California; Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, California
| | - Zhilin Qu
- UCLA Cardiovascular Research Laboratory; Department of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los Angeles, California.
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29
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Campos FO, Shiferaw Y, Prassl AJ, Boyle PM, Vigmond EJ, Plank G. Stochastic spontaneous calcium release events trigger premature ventricular complexes by overcoming electrotonic load. Cardiovasc Res 2015; 107:175-83. [PMID: 25969391 DOI: 10.1093/cvr/cvv149] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 05/07/2015] [Indexed: 12/21/2022] Open
Abstract
AIMS Premature ventricular complexes (PVCs) due to spontaneous calcium (Ca) release (SCR) events at the cell level can precipitate ventricular arrhythmias. However, the mechanistic link between SCRs and PVC formation remains incompletely understood. The aim of this study was to investigate the conditions under which delayed afterdepolarizations resulting from stochastic subcellular SCR events can overcome electrotonic source-sink mismatch, leading to PVC initiation. METHODS AND RESULTS A stochastic subcellular-scale mathematical model of SCR was incorporated in a realistic model of the rabbit ventricles and Purkinje system (PS). Elevated levels of diastolic sarcoplasmic reticulum Ca(2+) (CaSR) were imposed until triggered activity was observed, allowing us to compile statistics on probability, timing, and location of PVCs. At CaSR≥ 1500 µmol/L PVCs originated in the PS. When SCR was incapacitated in the PS, PVCs also emerged in the ventricles, but at a higher CaSR (≥1550 µmol/L) and with longer waiting times. For each model configuration tested, the probability of PVC occurrence increased from 0 to 100% within a well-defined critical CaSR range; this transition was much more abrupt in organ-scale models (∼50 µmol/L CaSR range) than in the tissue strand (∼100 µmol/L) or single-cell (∼450 µmol/L) models. Among PVCs originating in the PS, ∼68% were located near Purkinje-ventricular junctions (<1 mm). CONCLUSION SCR events overcome source-sink mismatch to trigger PVCs at a critical CaSR threshold. Above this threshold, PVCs emerge due to increased probability and reduced variability in timing of SCR events, leading to significant diastolic depolarization. Sites of lower electronic load, such as the PS, are preferential locations for triggering.
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Affiliation(s)
| | - Yohannes Shiferaw
- Department of Physics, California State University, Northridge, CA, USA
| | - Anton J Prassl
- Institute of Biophysics, Medical University of Graz, Graz, Austria
| | - Patrick M Boyle
- Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Edward J Vigmond
- LIRYC Institute, University of Bordeaux, Bordeaux, France Department of Electrical and Computer Engineering, University of Calgary, Calgary, Canada
| | - Gernot Plank
- Institute of Biophysics, Medical University of Graz, Graz, Austria
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30
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Perspective: a dynamics-based classification of ventricular arrhythmias. J Mol Cell Cardiol 2015; 82:136-52. [PMID: 25769672 DOI: 10.1016/j.yjmcc.2015.02.017] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 02/05/2015] [Accepted: 02/20/2015] [Indexed: 02/04/2023]
Abstract
Despite key advances in the clinical management of life-threatening ventricular arrhythmias, culminating with the development of implantable cardioverter-defibrillators and catheter ablation techniques, pharmacologic/biologic therapeutics have lagged behind. The fundamental issue is that biological targets are molecular factors. Diseases, however, represent emergent properties at the scale of the organism that result from dynamic interactions between multiple constantly changing molecular factors. For a pharmacologic/biologic therapy to be effective, it must target the dynamic processes that underlie the disease. Here we propose a classification of ventricular arrhythmias that is based on our current understanding of the dynamics occurring at the subcellular, cellular, tissue and organism scales, which cause arrhythmias by simultaneously generating arrhythmia triggers and exacerbating tissue vulnerability. The goal is to create a framework that systematically links these key dynamic factors together with fixed factors (structural and electrophysiological heterogeneity) synergistically promoting electrical dispersion and increased arrhythmia risk to molecular factors that can serve as biological targets. We classify ventricular arrhythmias into three primary dynamic categories related generally to unstable Ca cycling, reduced repolarization, and excess repolarization, respectively. The clinical syndromes, arrhythmia mechanisms, dynamic factors and what is known about their molecular counterparts are discussed. Based on this framework, we propose a computational-experimental strategy for exploring the links between molecular factors, fixed factors and dynamic factors that underlie life-threatening ventricular arrhythmias. The ultimate objective is to facilitate drug development by creating an in silico platform to evaluate and predict comprehensively how molecular interventions affect not only a single targeted arrhythmia, but all primary arrhythmia dynamics categories as well as normal cardiac excitation-contraction coupling.
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31
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Qu Z, Weiss JN. Mechanisms of ventricular arrhythmias: from molecular fluctuations to electrical turbulence. Annu Rev Physiol 2014; 77:29-55. [PMID: 25340965 DOI: 10.1146/annurev-physiol-021014-071622] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Ventricular arrhythmias have complex causes and mechanisms. Despite extensive investigation involving many clinical, experimental, and computational studies, effective biological therapeutics are still very limited. In this article, we review our current understanding of the mechanisms of ventricular arrhythmias by summarizing the state of knowledge spanning from the molecular scale to electrical wave behavior at the tissue and organ scales and how the complex nonlinear interactions integrate into the dynamics of arrhythmias in the heart. We discuss the challenges that we face in synthesizing these dynamics to develop safe and effective novel therapeutic approaches.
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Affiliation(s)
- Zhilin Qu
- Departments of 1Medicine (Cardiology) and
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Myles RC, Wang L, Bers DM, Ripplinger CM. Decreased inward rectifying K+ current and increased ryanodine receptor sensitivity synergistically contribute to sustained focal arrhythmia in the intact rabbit heart. J Physiol 2014; 593:1479-93. [PMID: 25772297 DOI: 10.1113/jphysiol.2014.279638] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 08/27/2014] [Accepted: 08/30/2014] [Indexed: 01/18/2023] Open
Abstract
KEY POINTS Heart failure leads to dramatic electrophysiological remodelling as a result of numerous cellular and tissue-level changes. Important cellular changes include increased sensitivity of ryanodine receptors (RyRs) to Ca(2+) release and down-regulation of the inward rectifying K(+) current (IK1), both of which contribute to triggered action potentials in isolated cells. We studied the role of increased RyR sensitivity and decreased IK1 in contributing to focal arrhythmia in the intact non-failing rabbit heart using optical mapping and pharmacological manipulation of RyRs and IK1. Neither increased RyR sensitivity or decreased IK1 alone led to significant increases in arrhythmia following local sympathetic stimulation; however, in combination, these two factors led to a significant increase in premature ventricular complexes and focal ventricular tachycardia. These results suggest synergism between increased RyR sensitivity and decreased IK1 in contributing to focal arrhythmia in the intact heart and may provide important insights into novel anti-arrhythmic treatments in heart failure. ABSTRACT Heart failure (HF) results in dramatic electrophysiological remodelling, including increased sensitivity of ryanodine receptors (RyRs) and decreased inward rectifying K(+) current (IK1), which predisposes HF myocytes to delayed afterdepolarizations and triggered activity. Therefore, we sought to determine the role of increased RyR sensitivity and decreased IK1 in contributing to focal arrhythmia in the intact non-failing heart. Optical mapping of transmembrane potential and intracellular Ca(2+) was performed in Langendorff-perfused rabbit hearts (n = 15). Local β-adrenergic receptor stimulation with noradrenaline (norepinephrine; NA, 50 μl, 250 μM) was applied to elicit focal activity (premature ventricular complexes (PVCs) or ventricular tachycardia (VT ≥ 3 beats)). NA was administered under control conditions (CTL) and following pretreatment with 50 μM BaCl2 to reduce IK1, or 200 μM caffeine (Caff) to sensitize RyRs, both alone and in combination. Local NA injection resulted in Ca(2+)-driven PVCs arising from the injection site in all hearts studied. No increase in NA-mediated PVCs was observed following pretreatment with either BaCl2 or Caff alone (CTL: 1.1 ± 0.7, BaCl2: 1.0 ± 0.7, Caff: 1.3 ± 0.8 PVCs/injection, P not significant). However, pretreatment with the combination of BaCl2 + Caff resulted in a significant increase in PVCs (2.3 ± 2.8 PVCs/injection, P < 0.05 vs. CTL, BaCl2, Caff). Additionally, pretreatment with BaCl2 + Caff led to sustained monomorphic VT arising from the NA application site in all hearts studied, which lasted up to 6 min following a single NA injection. VT was never observed under any other condition suggesting synergism between increased RyR sensitivity and decreased IK1 in contributing to focal activity. These findings may have important implications for the understanding and prevention of focal arrhythmia in HF.
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Affiliation(s)
- Rachel C Myles
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK
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Kandel SM, Roth BJ. Intracellular calcium and the mechanism of the dip in the anodal strength-interval curve in cardiac tissue. Circ J 2014; 78:1127-35. [PMID: 24583915 DOI: 10.1253/circj.cj-13-1261] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND The strength-interval (SI) curve is an important measure of refractoriness in cardiac tissue. The anodal SI curve contains a "dip" in which the S2 threshold increases with interval. Two explanations exist for this dip: (1) electrotonic interaction between regions of depolarization and hyperpolarization; and (2) the sodium-calcium exchange (NCX) current. The goal of this study is to use mathematical modeling to determine which explanation is correct. METHODS AND RESULTS The bidomain model represents cardiac tissue and the Luo-Rudy model describes the active membrane. The SI curve is determined by applying a threshold stimulus at different time intervals after a previous action potential. During space-clamped and equal-anisotropy-ratios simulations, anodal excitation does not occur. During unequal-anisotropy-ratios simulations, electrotonic currents, not membrane currents, are present during the few milliseconds before excitation. The dip disappears with no NCX current, but is present with 50% or 75% reduction of it. The calcium-induced-calcium-release (CICR) current has little effect on the dip. CONCLUSIONS These results indicate that neither the NCX nor the CICR current is responsible for the dip in the anodal SI curve. It is caused by the electrotonic interaction between regions of depolarization and hyperpolarization following the S2 stimulus.
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Wang L, Myles RC, De Jesus NM, Ohlendorf AKP, Bers DM, Ripplinger CM. Optical mapping of sarcoplasmic reticulum Ca2+ in the intact heart: ryanodine receptor refractoriness during alternans and fibrillation. Circ Res 2014; 114:1410-21. [PMID: 24568740 DOI: 10.1161/circresaha.114.302505] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Sarcoplasmic reticulum (SR) Ca(2+) cycling is key to normal excitation-contraction coupling but may also contribute to pathological cardiac alternans and arrhythmia. OBJECTIVE To measure intra-SR free [Ca(2+)] ([Ca(2+)]SR) changes in intact hearts during alternans and ventricular fibrillation (VF). METHODS AND RESULTS Simultaneous optical mapping of Vm (with RH237) and [Ca(2+)]SR (with Fluo-5N AM) was performed in Langendorff-perfused rabbit hearts. Alternans and VF were induced by rapid pacing. SR Ca(2+) and action potential duration (APD) alternans occurred in-phase, but SR Ca(2+) alternans emerged first as cycle length was progressively reduced (217±10 versus 190±13 ms; P<0.05). Ryanodine receptor (RyR) refractoriness played a key role in the onset of SR Ca(2+) alternans, with SR Ca(2+) release alternans routinely occurring without changes in diastolic [Ca(2+)]SR. Sensitizing RyR with caffeine (200 μmol/L) significantly reduced the pacing threshold for both SR Ca(2+) and APD alternans (188±15 and 173±12 ms; P<0.05 versus baseline). Caffeine also reduced the magnitude of spatially discordant SR Ca(2+) alternans, but not APD alternans, the pacing threshold for discordance, or threshold for VF. During VF, [Ca(2+)]SR was high, but RyR remained nearly continuously refractory, resulting in minimal SR Ca(2+) release throughout VF. CONCLUSIONS In intact hearts, RyR refractoriness initiates SR Ca(2+) release alternans that can be amplified by diastolic [Ca(2+)]SR alternans and lead to APD alternans. Sensitizing RyR suppresses spatially concordant but not discordant SR Ca(2+) and APD alternans. Despite increased [Ca(2+)]SR during VF, SR Ca(2+) release was nearly continuously refractory. This novel method provides insight into SR Ca(2+) handling during cardiac alternans and arrhythmia.
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Affiliation(s)
- Lianguo Wang
- From the Department of Pharmacology, School of Medicine, University of California, Davis (L.W., N.M.D.J., A.K.P.O., D.M.B., C.M.R.); and Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom (R.C.M.)
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Zamiri N, Massé S, Ramadeen A, Kusha M, Hu X, Azam MA, Liu J, Lai PFH, Vigmond EJ, Boyle PM, Behradfar E, Al-Hesayen A, Waxman MB, Backx P, Dorian P, Nanthakumar K. Dantrolene improves survival after ventricular fibrillation by mitigating impaired calcium handling in animal models. Circulation 2014; 129:875-85. [PMID: 24403563 DOI: 10.1161/circulationaha.113.005443] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Resistant ventricular fibrillation, refibrillation. and diminished myocardial contractility are important factors leading to poor survival after cardiac arrest. We hypothesized that dantrolene improves survival after ventricular fibrillation (VF) by rectifying the calcium dysregulation caused by VF. METHODS AND RESULTS VF was induced in 26 Yorkshire pigs for 4 minutes. Cardiopulmonary resuscitation was then commenced for 3 minutes, and dantrolene or isotonic saline was infused at the onset of cardiopulmonary resuscitation. Animals were defibrillated and observed for 30 minutes. To study the effect of VF on calcium handling and its modulation by dantrolene, hearts from 14 New Zealand rabbits were Langendorff-perfused. The inducibility of VF after dantrolene administration was documented. Optical mapping was performed to evaluate diastolic spontaneous calcium elevations as a measure of cytosolic calcium leak. The sustained return of spontaneous circulation (systolic blood pressure ≥60 mm Hg) was achieved in 85% of the dantrolene group in comparison with 39% of controls (P=0.02). return of spontaneous circulation was achieved earlier in dantrolene-treated pigs after successful defibrillation (21 ± 6 s versus 181 ± 57 s in controls, P=0.005). The median number of refibrillation episodes was lower in the dantrolene group (0 versus 1, P=0.04). In isolated rabbit hearts, the successful induction of VF was achieved in 83% of attempts in controls versus 41% in dantrolene-treated hearts (P=0.007). VF caused diastolic calcium leaks in the form of spontaneous calcium elevations. Administration of 20 μmol/L dantrolene significantly decreased spontaneous calcium elevation amplitude versus controls. (0.024 ± 0.013 versus 0.12 ± 0.02 arbitrary unit [200-ms cycle length], P=0.001). CONCLUSIONS Dantrolene infusion during cardiopulmonary resuscitation facilitates successful defibrillation, improves hemodynamics postdefibrillation, decreases refibrillation, and thus improves survival after cardiac arrest. The effects are mediated through normalizing VF-induced dysfunctional calcium cycling.
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Affiliation(s)
- Nima Zamiri
- From The Hull Family Cardiac Fibrillation Management Laboratory, University Health Network, University of Toronto, Toronto, ON, Canada (A.M., N.Z., S.M., M.K., M.A.A, P.F.H.L., M.B.W., K.N.); Keenan Research Centre, Li Ka Shing Knowledge Institute, St Michael's Hospital, Toronto, ON, Canada (A.R., X.H., A.A.-H., P.D.); Institute of Medical Science, University of Toronto, Toronto, ON, Canada (N.Z.); Department of Physiology, University of Toronto, Toronto, ON, Canada (J.L., P.B.); Institute LIRYC, Université Bordeaux 1, Bordeaux, France (E.J.V.); Institute for Computational Medicine, Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD (P.M.B.); and Department of Electrical Engineering, University of Calgary, Calgary, AB, Canada (E.B.)
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Chang PC, Hsieh YC, Hsueh CH, Weiss JN, Lin SF, Chen PS. Apamin induces early afterdepolarizations and torsades de pointes ventricular arrhythmia from failing rabbit ventricles exhibiting secondary rises in intracellular calcium. Heart Rhythm 2013; 10:1516-24. [PMID: 23835258 PMCID: PMC3832504 DOI: 10.1016/j.hrthm.2013.07.003] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2013] [Indexed: 11/15/2022]
Abstract
BACKGROUND A secondary rise of intracellular Ca(2+) (Cai) and an upregulation of apamin-sensitive K(+) current (I(KAS)) are characteristic findings of failing ventricular myocytes. We hypothesize that apamin, a specific I(KAS) blocker, may induce torsades de pointes (TdP) ventricular arrhythmia from failing ventricles exhibiting secondary rises of Cai. OBJECTIVE To test the hypothesis that small conductance Ca(2+) activated IKAS maintains repolarization reserve and prevents ventricular arrhythmia in a rabbit model of heart failure (HF). METHODS We performed Langendorff perfusion and optical mapping studies in 7 hearts with pacing-induced HF and in 5 normal control rabbit hearts. Atrioventricular block was created by cryoablation to allow pacing at slow rates. RESULTS The left ventricular ejection fraction reduced from 69.1% [95% confidence interval 62.3%-76.0%] before pacing to 30.4% [26.8%-34.0%] (N = 7; P < .001) after pacing. The corrected QT interval in failing ventricles was 337 [313-360] ms at baseline and 410 [381-439] ms after applying 100 nmol/L of apamin (P = .01). Apamin induced early afterdepolarizations (EADs) in 6 ventricles, premature ventricular beats (PVBs) in 7 ventricles, and polymorphic ventricular tachycardia consistent with TdP in 4 ventricles. The earliest activation site of EADs and PVBs always occurred at the site with long action potential duration and large amplitude of the secondary rises of Ca(i). Apamin induced secondary rises of Ca(i) in 1 nonfailing ventricle, but no EAD or TdP were observed. CONCLUSIONS In HF ventricles, apamin induces EADs, PVBs, and TdP from areas with secondary rises of Ca(i). I(KAS) is important in maintaining repolarization reserve and preventing TdP in HF ventricles.
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Affiliation(s)
- Po-Cheng Chang
- Krannert Institute of Cardiology and the Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana; Second Section of Cardiology, Department of Medicine, Chang Gung Memorial Hospital and Chang Gung University School of Medicine, Taoyuan, Taiwan
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Lee YS, Chang PC, Hsueh CH, Maruyama M, Park HW, Rhee KS, Hsieh YC, Shen C, Weiss JN, Chen Z, Lin SF, Chen PS. Apamin-sensitive calcium-activated potassium currents in rabbit ventricles with chronic myocardial infarction. J Cardiovasc Electrophysiol 2013; 24:1144-53. [PMID: 23718850 DOI: 10.1111/jce.12176] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2013] [Revised: 04/13/2013] [Accepted: 04/22/2013] [Indexed: 01/06/2023]
Abstract
INTRODUCTION The apamin-sensitive small-conductance calcium-activated potassium current (IKAS ) is increased in heart failure. It is unknown if myocardial infarction (MI) is also associated with an increase of IKAS . METHODS AND RESULTS We performed Langendorff perfusion and optical mapping in 6 normal hearts and 10 hearts with chronic (5 weeks) MI. An additional 6 normal and 10 MI hearts were used for patch clamp studies. The infarct size was 25% (95% confidence interval, 20-31) and the left ventricular ejection fraction was 50 (46-54). The rabbits did not have symptoms of heart failure. The action potential duration measured to 80% repolarization (APD80 ) in the peri-infarct zone (PZ) was 150 (142-159) milliseconds, significantly (P = 0.01) shorter than that in the normal ventricles (167 [158-177] milliseconds. The intracellular Ca transient duration was also shorter in the PZ (148 [139-157] milliseconds) than that in normal ventricles (168 [157-180] milliseconds; P = 0.017). Apamin prolonged the APD80 in PZ by 9.8 (5.5-14.1)%, which is greater than that in normal ventricles (2.8 [1.3-4.3]%, P = 0.006). Significant shortening of APD80 was observed at the cessation of rapid pacing in MI but not in normal ventricles. Apamin prevented postpacing APD80 shortening. Patch clamp studies showed that IKAS was significantly higher in the PZ cells (2.51 [1.55-3.47] pA/pF, N = 17) than in the normal cells (1.08 [0.36-1.80] pA/pF, N = 15, P = 0.019). CONCLUSION We conclude that IKAS is increased in MI ventricles and contributes significantly to ventricular repolarization especially during tachycardia.
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Affiliation(s)
- Young Soo Lee
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indianapolis, Indiana, USA; Division of Cardiology, Department of Internal Medicine, Catholic University of Daegu School of Medicine, Daegu, Korea
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Experimentally calibrated population of models predicts and explains intersubject variability in cardiac cellular electrophysiology. Proc Natl Acad Sci U S A 2013; 110:E2098-105. [PMID: 23690584 DOI: 10.1073/pnas.1304382110] [Citation(s) in RCA: 198] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Cellular and ionic causes of variability in the electrophysiological activity of hearts from individuals of the same species are unknown. However, improved understanding of this variability is key to enable prediction of the response of specific hearts to disease and therapies. Limitations of current mathematical modeling and experimental techniques hamper our ability to provide insight into variability. Here, we describe a methodology to unravel the ionic determinants of intersubject variability exhibited in experimental recordings, based on the construction and calibration of populations of models. We illustrate the methodology through its application to rabbit Purkinje preparations, because of their importance in arrhythmias and safety pharmacology assessment. We consider a set of equations describing the biophysical processes underlying rabbit Purkinje electrophysiology, and we construct a population of over 10,000 models by randomly assigning specific parameter values corresponding to ionic current conductances and kinetics. We calibrate the model population by closely comparing simulation output and experimental recordings at three pacing frequencies. We show that 213 of the 10,000 candidate models are fully consistent with the experimental dataset. Ionic properties in the 213 models cover a wide range of values, including differences up to ±100% in several conductances. Partial correlation analysis shows that particular combinations of ionic properties determine the precise shape, amplitude, and rate dependence of specific action potentials. Finally, we demonstrate that the population of models calibrated using data obtained under physiological conditions quantitatively predicts the action potential duration prolongation caused by exposure to four concentrations of the potassium channel blocker dofetilide.
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Functional roles of KATP channel subunits in metabolic inhibition. J Mol Cell Cardiol 2013; 62:90-8. [PMID: 23624089 DOI: 10.1016/j.yjmcc.2013.04.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2012] [Revised: 03/11/2013] [Accepted: 04/15/2013] [Indexed: 11/23/2022]
Abstract
ATP-sensitive potassium channel (KATP) activation can drastically shorten action potential duration (APD) in metabolically compromised myocytes. We showed previously that SUR1 with Kir6.2 forms the functional channel in mouse atria while Kir6.2 and SUR2A predominate in ventricles. SUR1 is more sensitive to metabolic stress than SUR2A, raising the possibility that KATP in atria and ventricles may respond differently to metabolic stress. Action potential duration (APD) and calcium transient duration (CaTD) were measured simultaneously in both atria and ventricles by optical mapping of the posterior surface of Langendorff-perfused hearts from C57BL wild-type (WT; n=11), Kir6.2(-/-) (n=5), and SUR1(-/-) (n=6) mice during metabolic inhibition (MI, 0mM glucose+2mM sodium cyanide). After variable delay, MI led to significant shortening of APD in WT hearts. On average, atrial APD shortened by 60.5 ± 2.7% at 13.1 ± 2.1 min (n=6, p<0.01) after onset of MI. Ventricular APD shortening (56.4 ± 10.0% shortening at 18.2 ± 1.8 min) followed atrial APD shortening. In SUR1(-/-) hearts (n=6), atrial APD shortening was abolished, but ventricular shortening (65.0 ± 15.4% at 25.33 ± 4.48 min, p<0.01) was unaffected. In Kir6.2(-/-) hearts, two disparate responses to MI were observed; 3 of 5 hearts displayed slight shortening of APD in the ventricles (24 ± 3%, p<0.05) and atria (39.0 ± 1.9%, p<0.05) but this shortening occurred later and to much less extent than in WT (p<0.05). Marked prolongation of ventricular APD was observed in the remaining hearts (327% and 489% prolongation) and was associated with occurrence of ventricular tachyarrhythmias. The results confirm that Kir6.2 contributes to APD shortening in both atria and ventricle during metabolic stress, and that SUR1 is required for atrial APD shortening while SUR2A is required for ventricular APD shortening. Importantly, the results show that the presence of SUR1-dependent KATP in the atria results in the action potential being more susceptible to metabolically driven shortening than the ventricle.
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Xiao L, Koopmann TT, Ördög B, Postema PG, Verkerk AO, Iyer V, Sampson KJ, Boink GJJ, Mamarbachi MA, Varro A, Jordaens L, Res J, Kass RS, Wilde AA, Bezzina CR, Nattel S. Unique cardiac Purkinje fiber transient outward current β-subunit composition: a potential molecular link to idiopathic ventricular fibrillation. Circ Res 2013; 112:1310-22. [PMID: 23532596 DOI: 10.1161/circresaha.112.300227] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
RATIONALE A chromosomal haplotype producing cardiac overexpression of dipeptidyl peptidase-like protein-6 (DPP6) causes familial idiopathic ventricular fibrillation. The molecular basis of transient outward current (I(to)) in Purkinje fibers (PFs) is poorly understood. We hypothesized that DPP6 contributes to PF I(to) and that its overexpression might specifically alter PF I(to) properties and repolarization. OBJECTIVE To assess the potential role of DPP6 in PF I(to). METHODS AND RESULTS Clinical data in 5 idiopathic ventricular fibrillation patients suggested arrhythmia origin in the PF-conducting system. PF and ventricular muscle I(to) had similar density, but PF I(to) differed from ventricular muscle in having tetraethylammonium sensitivity and slower recovery. DPP6 overexpression significantly increased, whereas DPP6 knockdown reduced, I(to) density and tetraethylammonium sensitivity in canine PF but not in ventricular muscle cells. The K(+)-channel interacting β-subunit K(+)-channel interacting protein type-2, essential for normal expression of I(to) in ventricular muscle, was weakly expressed in human PFs, whereas DPP6 and frequenin (neuronal calcium sensor-1) were enriched. Heterologous expression of Kv4.3 in Chinese hamster ovary cells produced small I(to); I(to) amplitude was greatly enhanced by coexpression with K(+)-channel interacting protein type-2 or DPP6. Coexpression of DPP6 with Kv4.3 and K(+)-channel interacting protein type-2 failed to alter I(to) compared with Kv4.3/K(+)-channel interacting protein type-2 alone, but DPP6 expression with Kv4.3 and neuronal calcium sensor-1 (to mimic PF I(to) composition) greatly enhanced I(to) compared with Kv4.3/neuronal calcium sensor-1 and recapitulated characteristic PF kinetic/pharmacological properties. A mathematical model of cardiac PF action potentials showed that I(to) enhancement can greatly accelerate PF repolarization. CONCLUSIONS These results point to a previously unknown central role of DPP6 in PF I(to), with DPP6 gain of function selectively enhancing PF current, and suggest that a DPP6-mediated PF early-repolarization syndrome might be a novel molecular paradigm for some forms of idiopathic ventricular fibrillation.
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Affiliation(s)
- Ling Xiao
- Department of Medicine, Montreal Heart Institute and Université de Montréal, Montreal, QC, Canada
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Electrical storm: recent pathophysiological insights and therapeutic consequences. Basic Res Cardiol 2013; 108:336. [DOI: 10.1007/s00395-013-0336-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Revised: 01/29/2013] [Accepted: 02/04/2013] [Indexed: 01/01/2023]
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Miura M, Murai N, Hattori T, Nagano T, Stuyvers BD, Shindoh C. Role of reactive oxygen species and Ca(2+) dissociation from the myofilaments in determination of Ca(2+) wave propagation in rat cardiac muscle. J Mol Cell Cardiol 2012; 56:97-105. [PMID: 23266595 DOI: 10.1016/j.yjmcc.2012.12.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 11/14/2012] [Accepted: 12/10/2012] [Indexed: 11/30/2022]
Abstract
Ca(2+) waves are initiated not only by Ca(2+) leak from the sarcoplasmic reticulum (SR), but also by Ca(2+) dissociation from the myofilaments in the myocardium with nonuniform contraction. We investigated whether contractile properties and the production of reactive oxygen species (ROS) affect Ca(2+) wave propagation. Trabeculae were obtained from 76 rat hearts. Force was measured with a strain gauge, sarcomere length with a laser diffraction technique, and [Ca(2+)](i) with fura-2 and a CCD camera (24°C, 2.0mmol/L [Ca(2+)](o)). ROS production was estimated from 2',7'-dichlorofluorescein (DCF) fluorescence. Trabeculae were regionally exposed to a jet of solution containing 1) 10mmol/L Ca(2+) to initiate Ca(2+) waves by SR Ca(2+) leak due to Ca(2+) overload within the jet-exposed region, and 2) 0.2mmol/L Ca(2+) or 5mmol/L caffeine to initiate such waves by Ca(2+) dissociation from the myofilaments due to nonuniform contraction. Ca(2+) waves were induced by stimulus trains for 7.5s. Ten-percent muscle stretch increased DCF fluorescence and accelerated Ca(2+) waves initiated due to both Ca(2+) overload and nonuniform contraction. Preincubation with 3μmol/L diphenyleneiodonium or 10μmol/L colchicine suppressed the increase in DCF fluorescence but suppressed acceleration of Ca(2+) waves initiated only due to Ca(2+) overload. Irrespective of preincubation with colchicine, reduction of force after the addition of 10μmol/L blebbistatin did not decelerate Ca(2+) waves initiated due to Ca(2+) overload, while it did decelerate waves initiated due to nonuniform contraction. These results suggest that Ca(2+) wave propagation is modulated by ROS production through an intact microtubule network only during stretch and may be additionally modulated by Ca(2+) dissociated from the myofilaments in the case of nonuniform contraction.
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Affiliation(s)
- Masahito Miura
- Department of Clinical Physiology, Health Science, Tohoku University Graduate School of Medicine, Sendai 980-8574, Japan.
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Jin Q, Zhang N, Zhou J, Lin CJ, Pang Y, Gu G, Shen WF, Wu LQ. The effect of pinacidil on postshock activation and ventricular defibrillation threshold in canine hearts. Acta Pharmacol Sin 2012; 33:1488-94. [PMID: 23064720 DOI: 10.1038/aps.2012.96] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
AIM To determine the postshock activation patterns with both successful and failed shocks in a canine model of ventricular fibrillation, and whether piniacidil, an early after-depolarization (EAD) inhibitor, altered the defibrillation threshold (DFT) and postshock activation patterns. METHODS In 6 beagles, a basket catheter with 64 unipolar electrodes was placed in the LV for global endocardial mapping, a monophasic action potential catheter was inserted into the LV apex, and a catheter with the negative electrode in the right ventricle and the positive electrode in the superior vena cava was inserted for defibrillation. The DFT, 90% action potential duration (APD(90)) and activation recovery interval (ARI) were evaluated before and after pinacidil administration (loading dosage 0.5 mg/kg and maintenance dosage 0.5 mg·kg(-1)·h(-1), iv). Electrical heterogeneities were defined with the dispersion of ARI. After successful and failed shocks with near-DFT strength, the earliest postshock activation patterns (focal or nonfocal endocardial activation), interval and location were detected. RESULTS Pinacidil significantly decreased APD(90) (from 178±16 ms to 168±18 ms) and ARI from (152±10 ms to 143±10 ms) at pacing cycle length of 300 ms. The drug significantly increased VF activation rate (from 10.0±1.9 Hz to 10.8±2.0 Hz). The drug did not affect the dispersion of ARI, neither it changed DFT (baseline: 480±110 V; pinacidil: 425±55 V, P>0.05). The earliest postshock activation arose locally on the LV apical endocardium before and after the drug treatment. Pinacidil significantly prolonged the postshock cycle length of cycles 2 to 5 for the successful episodes but not for the failed episodes. CONCLUSION Pinacidil increases the postshock cycle length suggesting that EAD may play a role in postshock activation, while it fails to alter DFT suggesting that EAD produced by shock does not determine a defibrillation success or failure.
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Di Diego JM, Sicouri S, Myles RC, Burton FL, Smith GL, Antzelevitch C. Optical and electrical recordings from isolated coronary-perfused ventricular wedge preparations. J Mol Cell Cardiol 2012; 54:53-64. [PMID: 23142540 DOI: 10.1016/j.yjmcc.2012.10.017] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Revised: 10/22/2012] [Accepted: 10/29/2012] [Indexed: 01/06/2023]
Abstract
The electrophysiological heterogeneity that exists across the ventricular wall in the mammalian heart has long been recognized, but remains an area that is incompletely understood. Experimental studies of the mechanisms of arrhythmogenesis in the whole heart often examine the epicardial surface in isolation and thereby disregard transmural electrophysiology. Significant heterogeneity exists in the electrophysiological properties of cardiomyocytes isolated from different layers of the ventricular wall, and given that regional heterogeneities of membrane repolarization properties can influence the electrophysiological substrate for re-entry, the diversity of cell types and characteristics spanning the ventricular wall is important in the study of arrhythmogenesis. For these reasons, coronary-perfused left ventricular wedge preparations have been developed to permit the study of transmural electrophysiology in the intact ventricle. Since the first report by Yan and Antzelevitch in 1996, electrical recordings from the transmural surface of canine wedge preparations have provided a wealth of data regarding the cellular basis for the electrocardiogram, the role of transmural heterogeneity in arrhythmogenesis, and differences in the response of the different ventricular layers to drugs and neurohormones. Use of the wedge preparation has since been expanded to other species and more recently it has also been widely used in optical mapping studies. The isolated perfused wedge preparation has become an important tool in cardiac electrophysiology. In this review, we detail the methodology involved in recording both electrical and optical signals from the coronary-perfused wedge preparation and review the advances in cardiac electrophysiology achieved through study of the wedge.
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Affiliation(s)
- José M Di Diego
- Masonic Medical Research Laboratory, 2150 Bleecker St., Utica, NY 13501, USA
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Maruyama M, Xiao J, Zhou Q, Vembaiyan K, Chua SK, Rubart-von der Lohe M, Lin SF, Back TG, Chen SRW, Chen PS. Carvedilol analogue inhibits triggered activities evoked by both early and delayed afterdepolarizations. Heart Rhythm 2012; 10:101-7. [PMID: 22982970 DOI: 10.1016/j.hrthm.2012.09.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Indexed: 12/22/2022]
Abstract
BACKGROUND Carvedilol and its analogues suppress delayed afterdepolarizations (DADs) and catecholaminergic polymorphic ventricular tachycardias by direct action on the cardiac ryanodine receptor type 2 (RyR2). OBJECTIVE To test a hypothesis that carvedilol analogue may also prevent triggered activities (TAs) through the suppression of early afterdepolarizations (EADs). METHODS Intracellular Ca(2+) and membrane voltage were simultaneously recorded by using optical mapping technique in Langendorff-perfused mouse and rabbit hearts to study the effect of carvedilol analogue VK-II-36, which does not have significant beta-blocking effects. RESULTS Spontaneous intracellular Ca(2+) elevations (SCaEs) during diastole were induced by rapid ventricular pacing and isoproterenol infusion in intact rabbit ventricles. Systolic and diastolic SCaEs were simultaneously noted in Langendorff-perfused RyR2 R4496(+/-) mouse hearts after creating atrioventricular block. VK-II-36 effectively suppressed SCaEs and eliminated TAs observed in both mouse and rabbit ventricles. We tested the effect of VK-II-36 on EADs by using a rabbit model of acquired long QT syndrome, in which phase 2 and phase 3 EADs were observed in association with systolic SCaEs. VK-II-36 abolished the systolic SCaEs and phase 2 EADs, and greatly decreased the dispersion of repolarization and the amplitude of phase 3 EADs. VK-II-36 completely prevented EAD-mediated TAs in all ventricles studied. CONCLUSIONS A carvedilol analogue, VK-II-36, inhibits ventricular tachyarrhythmias in intact mouse and rabbit ventricles by the suppression of SCaEs, independent of beta-blocking activity. The RyR2 may be a potential target for treating focal ventricular arrhythmias triggered by either EADs or DADs.
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Affiliation(s)
- Mitsunori Maruyama
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
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Circulation Research
Thematic Synopsis. Circ Res 2012. [DOI: 10.1161/circresaha.112.280024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Abstract
RATIONALE β-Adrenergic receptor stimulation produces sarcoplasmic reticulum Ca(2+) overload and delayed afterdepolarizations in isolated ventricular myocytes. How delayed afterdepolarizations are synchronized to overcome the source-sink mismatch and produce focal arrhythmia in the intact heart remains unknown. OBJECTIVE To determine whether local β-adrenergic receptor stimulation produces spatiotemporal synchronization of delayed afterdepolarizations and to examine the effects of tissue geometry and cell-cell coupling on the induction of focal arrhythmia. METHODS AND RESULTS Simultaneous optical mapping of transmembrane potential and Ca(2+) transients was performed in normal rabbit hearts during subepicardial injections (50 μL) of norepinephrine (NE) or control (normal Tyrode's solution). Local NE produced premature ventricular complexes (PVCs) from the injection site that were dose-dependent (low-dose [30-60 μmol/L], 0.45±0.62 PVCs per injection; high-dose [125-250 μmol/L], 1.33±1.46 PVCs per injection; P<0.0001) and were inhibited by propranolol. NE-induced PVCs exhibited abnormal voltage-Ca(2+) delay at the initiation site and were inhibited by either sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPase inhibition or reduced perfusate [Ca(2+)], which indicates a Ca(2+)-mediated mechanism. NE-induced PVCs were more common at right ventricular than at left ventricular sites (1.48±1.50 versus 0.55±0.89, P<0.01), and this was unchanged after chemical ablation of endocardial Purkinje fibers, which suggests that source-sink interactions may contribute to the greater propensity to right ventricular PVCs. Partial gap junction uncoupling with carbenoxolone (25 μmol/L) increased focal activity (2.18±1.43 versus 1.33±1.46 PVCs per injection, P<0.05), which further supports source-sink balance as a critical mediator of Ca(2+)-induced PVCs. CONCLUSIONS These data provide the first experimental demonstration that localized β-adrenergic receptor stimulation produces spatiotemporal synchronization of sarcoplasmic reticulum Ca(2+) overload and release in the intact heart and highlight the critical nature of source-sink balance in initiating focal arrhythmias.
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Bapat A, Nguyen TP, Lee JH, Sovari AA, Fishbein MC, Weiss JN, Karagueuzian HS. Enhanced sensitivity of aged fibrotic hearts to angiotensin II- and hypokalemia-induced early afterdepolarization-mediated ventricular arrhythmias. Am J Physiol Heart Circ Physiol 2012; 302:H2331-40. [PMID: 22467308 DOI: 10.1152/ajpheart.00094.2012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Unlike young hearts, aged hearts are highly susceptible to early afterdepolarization (EAD)-mediated ventricular fibrillation (VF). This differential may result from age-related structural remodeling (fibrosis) or electrical remodeling of ventricular myocytes or both. We used optical mapping and microelectrode recordings in Langendorff-perfused hearts and patch-clamp recordings in isolated ventricular myocytes from aged (24-26 mo) and young (3-4 mo) rats to assess susceptibility to EADs and VF during either oxidative stress with ANG II (2 μM) or ionic stress with hypokalemia (2.7 mM). ANG II caused EAD-mediated VF in 16 of 19 aged hearts (83%) after 32 ± 7 min but in 0 of 9 young hearts (0%). ANG II-mediated VF was suppressed with KN-93 (Ca(2+)/calmodulin-dependent kinase inhibitor) and the reducing agent N-acetylcysteine. Hypokalemia caused EAD-mediated VF in 11 of 11 aged hearts (100%) after 7.4 ± 0.4 min. In 14 young hearts, however, VF did not occur in 6 hearts (43%) or was delayed in onset (31 ± 22 min, P < 0.05) in 8 hearts (57%). In patch-clamped myocytes, ANG II and hypokalemia (n = 6) induced EADs and triggered activity in both age groups (P = not significant) at a cycle length of >0.5 s. When myocytes of either age group were coupled to a virtual fibroblast using the dynamic patch-clamp technique, EADs arose in both groups at a cycle length of <0.5 s. Aged ventricles had significantly greater fibrosis and reduced connexin43 gap junction density compared with young hearts. The lack of differential age-related sensitivity at the single cell level in EAD susceptibility indicates that increased ventricular fibrosis in the aged heart plays a key role in increasing vulnerability to VF induced by oxidative and ionic stress.
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Affiliation(s)
- Aneesh Bapat
- Translational Arrhythmia Research Section, University of California-Los Angeles Cardiovascular Research Laboratory, USA
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Miura M, Hattori T, Murai N, Nagano T, Nishio T, Boyden PA, Shindoh C. Regional increase in extracellular potassium can be arrhythmogenic due to nonuniform muscle contraction in rat ventricular muscle. Am J Physiol Heart Circ Physiol 2012; 302:H2301-9. [PMID: 22447939 DOI: 10.1152/ajpheart.01161.2011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
In the ischemic myocardium, extracellular potassium ([K(+)](o)) increases to ≥20 mmol/l. To determine how lethal arrhythmias occur during ischemia, we investigated whether the increased spatial pattern of [K(+)](o), i.e., a regional or a global increase, affects the incidence of arrhythmias. Force, sarcomere length, membrane potential, and nonuniform intracellular Ca(2+) ([Ca(2+)](i)) were measured in rat ventricular trabeculae. A "regional" or "global" increase in [K(+)](o) was produced by exposing a restricted region of muscle to a jet of 30 mmol/l KCl or by superfusing trabeculae with a solution containing 30 mmol/l KCl, respectively. The increase in [Ca(2+)](i) (Ca(CW)) during Ca(2+) waves was measured (24°C, 3.0 mmol/l [Ca(2+)](o)). A regional increase in [K(+)](o) caused nonuniform [Ca(2+)](i) and contraction. In the presence of isoproterenol, the regional increase in [K(+)](o) induced sustained arrhythmias in 10 of 14 trabeculae, whereas the global increase did not induce such arrhythmias. During sustained arrhythmias, Ca(2+) surged within the jet-exposed region. In the absence of isoproterenol, the regional increase in [K(+)](o) increased Ca(CW), whereas the global increase decreased it. This increase in Ca(CW) with the regional increase in [K(+)](o) was not suppressed by 100 μmol/l streptomycin, whereas it was suppressed by 1) a combination of 10 μmol/l cilnidipine and 3 μmol/l SEA0400; 2) 20 mmol/l 2,3-butanedione monoxime; and 3) 10 μmol/l blebbistatin. A regional but not a global increase in [K(+)](o) induces sustained arrhythmias, probably due to nonuniform excitation-contraction coupling. The same mechanism may underlie arrhythmias during ischemia.
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Affiliation(s)
- Masahito Miura
- Department of Clinical Physiology, Health Science, Tohoku University Graduate School of Medicine, Sendai, Japan.
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