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Oraii A, Chaumont C, Rodriguez-Queralto O, Petzl A, Zado E, Markman TM, Hyman MC, Tschabrunn CM, Enriquez A, Shivamurthy P, Kumareswaran R, Riley MP, Lin D, Supple GE, Garcia FC, Schaller RD, Nazarian S, Frankel DS, Dixit S, Callans DJ, Marchlinski FE. Incremental Benefit of Stepwise Nonpulmonary Vein Trigger Provocation During Catheter Ablation of Atrial Fibrillation. JACC Clin Electrophysiol 2024; 10:1648-1659. [PMID: 39084740 DOI: 10.1016/j.jacep.2024.06.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Revised: 05/28/2024] [Accepted: 06/06/2024] [Indexed: 08/02/2024]
Abstract
BACKGROUND The importance of nonpulmonary vein (PV) triggers for the initiation/recurrence of atrial fibrillation (AF) is well established. OBJECTIVES This study sought to assess the incremental benefit of provocative maneuvers for identifying non-PV triggers. METHODS We included consecutive patients undergoing first-time AF ablation between 2020 and 2022. The provocation protocol included step 1, identification of spontaneous non-PV triggers after cardioversion of AF and/or during sinus rhythm; step 2, isoproterenol infusion (3, 6, 12, and 20-30 μg/min); and step 3, atrial burst pacing to induce AF followed by cardioversion during residual or low-dose isoproterenol infusion or induce focal atrial tachycardia. Non-PV triggers were defined as non-PV ectopic beats triggering AF or sustained focal atrial tachycardia. RESULTS Of 1,372 patients included, 883 (64.4%) underwent the complete stepwise provocation protocol with isoproterenol infusion and burst pacing, 334 (24.3%) isoproterenol infusion only, 77 (5.6%) burst pacing only, and 78 (5.7%) no provocative maneuvers (only step 1). Overall, 161 non-PV triggers were found in 135 (9.8%) patients. Of these, 51 (31.7%) non-PV triggers occurred spontaneously, and the remaining 110 (68.3%) required provocative maneuvers for induction. Among those receiving the complete stepwise provocation protocol, there was a 2.2-fold increase in the number of patients with non-PV triggers after isoproterenol infusion, and the addition of burst pacing after isoproterenol infusion led to a total increase of 3.6-fold with the complete stepwise provocation protocol. CONCLUSIONS The majority of non-PV triggers require provocative maneuvers for induction. A stepwise provocation protocol consisting of isoproterenol infusion followed by burst pacing identifies a 3.6-fold higher number of patients with non-PV triggers.
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Affiliation(s)
- Alireza Oraii
- Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Corentin Chaumont
- Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Oriol Rodriguez-Queralto
- Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Adrian Petzl
- Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Erica Zado
- Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Timothy M Markman
- Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Matthew C Hyman
- Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Cory M Tschabrunn
- Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Andres Enriquez
- Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Poojita Shivamurthy
- Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ramanan Kumareswaran
- Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Michael P Riley
- Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - David Lin
- Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Gregory E Supple
- Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Fermin C Garcia
- Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Robert D Schaller
- Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Saman Nazarian
- Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - David S Frankel
- Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Sanjay Dixit
- Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - David J Callans
- Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Francis E Marchlinski
- Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA.
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Hwang D, Liu X, Kote A, Reaso J, Andersson KT, Shehata MM, Ehdaie A, Wang X, Cingolani E, Ramireddy A, Braunstein ED, Chen LS, Li X, Goldhaber JI, Chen PS. Sympathetic toggled paroxysmal atrial fibrillation and recurrent premature atrial contractions in ambulatory patients. Heart Rhythm 2024:S1547-5271(24)02571-2. [PMID: 38762134 DOI: 10.1016/j.hrthm.2024.05.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 05/01/2024] [Accepted: 05/13/2024] [Indexed: 05/20/2024]
Abstract
BACKGROUND Autonomic nerve activity is important in the mechanisms of paroxysmal atrial fibrillation (PAF). OBJECTIVE The purpose of this study was to test the hypothesis that a single burst of skin sympathetic nerve activity (SKNA) can toggle on and off PAF or premature atrial contraction (PAC) clusters. METHODS Simultaneous recording of SKNA and electrocardiogram (neuECG) recording was performed over 7 days in patients with PAF. RESULTS In study 1, 8 patients (7 men and 1 woman; age 62 ± 8 years) had 124 episodes of PAF. An SKNA burst toggled both on and off PAF in 8 episodes (6.5%) (type 1), toggled on but not off in 12 episodes (9.7%) (type 2), and toggled on a PAC cluster followed by PAF in 4 episodes (3.2%) (type 3). The duration of these PAF episodes was <10 minutes. The remaining 100 episodes (80.6%) were associated with active SKNA bursts throughout PAF (type 4) and lasted longer than type 1 (P = .0185) and type 2 (P = .0027) PAF. There were 47 PAC clusters. Among them, 24 (51.1%) were toggled on and off, and 23 (48.9%) were toggled on but not off by an SKNA burst. In study 2, 17 patients (9 men and 8 women; age 58 ± 12 years) had <10 minutes of PAF (4, 8, 0, and 31 of types 1, 2, 3, and 4, respectively). There were significant circadian variations of all types of PAF. CONCLUSION A single SKNA burst can toggle short-duration PAF and PAC cluster episodes on and off. The absence of continued SKNA after the onset might have affected the maintenance of these arrhythmias.
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Affiliation(s)
- Daerin Hwang
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Xiao Liu
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Anxhela Kote
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Jewel Reaso
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - K Taiga Andersson
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Michael M Shehata
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Ashkan Ehdaie
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Xunzhang Wang
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Eugenio Cingolani
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Archana Ramireddy
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Eric D Braunstein
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Lan S Chen
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Xiaochun Li
- Department of Biostatistics and Health Data Science, Indiana University, Indianapolis, Indiana
| | - Joshua I Goldhaber
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Peng-Sheng Chen
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California.
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Li B, Lin M, Wu L. Drug-induced AF: Arrhythmogenic Mechanisms and Management Strategies. Arrhythm Electrophysiol Rev 2024; 13:e06. [PMID: 38706787 PMCID: PMC11066853 DOI: 10.15420/aer.2023.24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 01/12/2024] [Indexed: 05/07/2024] Open
Abstract
AF is a prevalent condition that is associated with various modifiable and unmodifiable risk factors. Drug-induced AF, despite being commonly under-recognised, can be relatively easy to manage. Numerous cardiovascular and non-cardiovascular agents, including catecholaminergic agents, adenosine, anti-tumour agents and others, have been reported to induce AF. However, the mechanisms underlying drug-induced AF are diverse and not fully understood. The complexity of clinical scenarios and insufficient knowledge regarding drug-induced AF have rendered the management of this condition complicated, and current treatment guidelines follow those for other types of AF. Here, we present a review of the epidemiology of drug-induced AF and highlight a range of drugs that can induce or exacerbate AF, along with their molecular and electrophysiological mechanisms. Given the inadequate evidence and lack of attention, further research is crucial to underscore the clinical significance of drug-induced AF, clarify the underlying mechanisms and develop effective treatment strategies for the condition.
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Affiliation(s)
- Bingxun Li
- Department of Cardiology, Peking University First HospitalBeijing, China
| | - Mingjie Lin
- Department of Cardiology, Qilu Hospital of Shandong University Qingdao BranchQingdao, China
| | - Lin Wu
- Department of Cardiology, Peking University First HospitalBeijing, China
- Key Laboratory of Medical Electrophysiology of the Ministry of Education and Institute of Cardiovascular Research, Southwest Medical UniversityLuzhou, China
- State Key Laboratory of Vascular Homeostasis and Remodeling, Peking UniversityBeijing, China
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Babini H, Jiménez-Sábado V, Stogova E, Arslanova A, Butt M, Dababneh S, Asghari P, Moore EDW, Claydon TW, Chiamvimonvat N, Hove-Madsen L, Tibbits GF. hiPSC-derived cardiomyocytes as a model to study the role of small-conductance Ca 2+-activated K + (SK) ion channel variants associated with atrial fibrillation. Front Cell Dev Biol 2024; 12:1298007. [PMID: 38304423 PMCID: PMC10830749 DOI: 10.3389/fcell.2024.1298007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 01/05/2024] [Indexed: 02/03/2024] Open
Abstract
Atrial fibrillation (AF), the most common arrhythmia, has been associated with different electrophysiological, molecular, and structural alterations in atrial cardiomyocytes. Therefore, more studies are required to elucidate the genetic and molecular basis of AF. Various genome-wide association studies (GWAS) have strongly associated different single nucleotide polymorphisms (SNPs) with AF. One of these GWAS identified the rs13376333 risk SNP as the most significant one from the 1q21 chromosomal region. The rs13376333 risk SNP is intronic to the KCNN3 gene that encodes for small conductance calcium-activated potassium channels type 3 (SK3). However, the functional electrophysiological effects of this variant are not known. SK channels represent a unique family of K+ channels, primarily regulated by cytosolic Ca2+ concentration, and different studies support their critical role in the regulation of atrial excitability and consequently in the development of arrhythmias like AF. Since different studies have shown that both upregulation and downregulation of SK3 channels can lead to arrhythmias by different mechanisms, an important goal is to elucidate whether the rs13376333 risk SNP is a gain-of-function (GoF) or a loss-of-function (LoF) variant. A better understanding of the functional consequences associated with these SNPs could influence clinical practice guidelines by improving genotype-based risk stratification and personalized treatment. Although research using native human atrial cardiomyocytes and animal models has provided useful insights, each model has its limitations. Therefore, there is a critical need to develop a human-derived model that represents human physiology more accurately than existing animal models. In this context, research with human induced pluripotent stem cells (hiPSC) and subsequent generation of cardiomyocytes derived from hiPSC (hiPSC-CMs) has revealed the underlying causes of various cardiovascular diseases and identified treatment opportunities that were not possible using in vitro or in vivo studies with animal models. Thus, the ability to generate atrial cardiomyocytes and atrial tissue derived from hiPSCs from human/patients with specific genetic diseases, incorporating novel genetic editing tools to generate isogenic controls and organelle-specific reporters, and 3D bioprinting of atrial tissue could be essential to study AF pathophysiological mechanisms. In this review, we will first give an overview of SK-channel function, its role in atrial fibrillation and outline pathophysiological mechanisms of KCNN3 risk SNPs. We will then highlight the advantages of using the hiPSC-CM model to investigate SNPs associated with AF, while addressing limitations and best practices for rigorous hiPSC studies.
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Affiliation(s)
- Hosna Babini
- Cellular and Regenerative Medicine Centre, BC Children’s Hospital Research Institute, Vancouver, BC, Canada
- Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Verónica Jiménez-Sábado
- Cellular and Regenerative Medicine Centre, BC Children’s Hospital Research Institute, Vancouver, BC, Canada
- Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
- IIB SANT PAU, and CIBERCV, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Ekaterina Stogova
- Cellular and Regenerative Medicine Centre, BC Children’s Hospital Research Institute, Vancouver, BC, Canada
- Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Alia Arslanova
- Cellular and Regenerative Medicine Centre, BC Children’s Hospital Research Institute, Vancouver, BC, Canada
- Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Mariam Butt
- Cellular and Regenerative Medicine Centre, BC Children’s Hospital Research Institute, Vancouver, BC, Canada
- Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Saif Dababneh
- Cellular and Regenerative Medicine Centre, BC Children’s Hospital Research Institute, Vancouver, BC, Canada
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Parisa Asghari
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Edwin D. W. Moore
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Thomas W. Claydon
- Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | | | - Leif Hove-Madsen
- IIB SANT PAU, and CIBERCV, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
- Instituto de Investigaciones Biomédicas de Barcelona (IIBB-CSIC), Barcelona, Spain
| | - Glen F. Tibbits
- Cellular and Regenerative Medicine Centre, BC Children’s Hospital Research Institute, Vancouver, BC, Canada
- Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
- Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada
- School of Biomedical Engineering, University of British Columbia, Vancouver, BC, Canada
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5
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Yi Y, Tianxin Y, Zhangchi L, Cui Z, Weiguo W, Bo Y. Pinocembrin attenuates susceptibility to atrial fibrillation in rats with pulmonary arterial hypertension. Eur J Pharmacol 2023; 960:176169. [PMID: 37925134 DOI: 10.1016/j.ejphar.2023.176169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 10/23/2023] [Accepted: 10/26/2023] [Indexed: 11/06/2023]
Abstract
BACKGROUND Pulmonary arterial hypertension (PAH) is a disease characterized by pulmonary vascular remodeling that triggers fibrosis and excessive myocardium apoptosis, ultimately facilitating atrial fibrillation (AF). In various rat models, Pinocembrin has anti-fibrotic and anti-apoptotic effects, reducing arrhythmia vulnerability. However, whether pinocembrin alleviates to AF in a PAH model remains unclear. The experiment aims to investigate how pinocembrin affects AF susceptibility in PAH rats and the possible mechanisms involved. METHODS The PAH model was induced by monocrotaline (MCT; i. p. 60 mg/kg). Concurrently, rats received pinocembrin (i.p.50 mg/kg) or saline. Hemodynamics parameters, electrocardiogram parameters, lung H.E. staining, atrial electrophysiological parameters, histology, Western blot, and TUNEL assay were detected. RESULTS Compared to the control rats, MCT-induced PAH rats possessed prominently enhancive mPAP (mean pulmonary artery pressure), pulmonary vascular remodeling, AF inducibility, HRV, right atrial myocardial fibrosis, apoptosis, atrial ERP, APD, and P-wave duration. Additionally, there were lowered protein levels of Cav1.2, Kv4.2, Kv4.3, and connexin 40 (CX40) in the MCT group in right atrial tissue. However, pinocembrin reversed the above pathologies and alleviated the activity of the Rho A/ROCKs signaling pathway, including the expression of Rho A, ROCK1, ROCK2, and its downstream MYPT-1, LIMK2, BCL-2, BAX, cleaved-caspase3 in right atrial and HL-1 cells. CONCLUSION Present data exhibited pinocembrin attenuated atrial electrical, ion-channel, and autonomic remodeling, diminished myocardial fibrosis and apoptosis levels, thereby reducing susceptibility to AF in the MCT-induced PAH rats. Furthermore, we found that pinocembrin exerted inhibitory action on the Rho A/ROCK signaling pathway, which may be potentially associated with its anti-AF effects.
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Affiliation(s)
- Yu Yi
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, 430060, PR China; Cardiovascular Research Institute, Wuhan University, Wuhan, 430060, PR China; Hubei Key Laboratory of Cardiology, Wuhan, 430060, PR China
| | - Ye Tianxin
- Department of Cardiology, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, PR China
| | - Liu Zhangchi
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, 430060, PR China; Cardiovascular Research Institute, Wuhan University, Wuhan, 430060, PR China; Hubei Key Laboratory of Cardiology, Wuhan, 430060, PR China
| | - Zhang Cui
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, 430060, PR China; Cardiovascular Research Institute, Wuhan University, Wuhan, 430060, PR China; Hubei Key Laboratory of Cardiology, Wuhan, 430060, PR China
| | - Wan Weiguo
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, 430060, PR China; Cardiovascular Research Institute, Wuhan University, Wuhan, 430060, PR China; Hubei Key Laboratory of Cardiology, Wuhan, 430060, PR China.
| | - Yang Bo
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, 430060, PR China; Cardiovascular Research Institute, Wuhan University, Wuhan, 430060, PR China; Hubei Key Laboratory of Cardiology, Wuhan, 430060, PR China.
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6
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Ramos-Mondragón R, Lozhkin A, Vendrov AE, Runge MS, Isom LL, Madamanchi NR. NADPH Oxidases and Oxidative Stress in the Pathogenesis of Atrial Fibrillation. Antioxidants (Basel) 2023; 12:1833. [PMID: 37891912 PMCID: PMC10604902 DOI: 10.3390/antiox12101833] [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: 08/18/2023] [Revised: 09/26/2023] [Accepted: 09/29/2023] [Indexed: 10/29/2023] Open
Abstract
Atrial fibrillation (AF) is the most common type of cardiac arrhythmia and its prevalence increases with age. The irregular and rapid contraction of the atria can lead to ineffective blood pumping, local blood stasis, blood clots, ischemic stroke, and heart failure. NADPH oxidases (NOX) and mitochondria are the main sources of reactive oxygen species in the heart, and dysregulated activation of NOX and mitochondrial dysfunction are associated with AF pathogenesis. NOX- and mitochondria-derived oxidative stress contribute to the onset of paroxysmal AF by inducing electrophysiological changes in atrial myocytes and structural remodeling in the atria. Because high atrial activity causes cardiac myocytes to expend extremely high energy to maintain excitation-contraction coupling during persistent AF, mitochondria, the primary energy source, undergo metabolic stress, affecting their morphology, Ca2+ handling, and ATP generation. In this review, we discuss the role of oxidative stress in activating AF-triggered activities, regulating intracellular Ca2+ handling, and functional and anatomical reentry mechanisms, all of which are associated with AF initiation, perpetuation, and progression. Changes in the extracellular matrix, inflammation, ion channel expression and function, myofibril structure, and mitochondrial function occur during the early transitional stages of AF, opening a window of opportunity to target NOX and mitochondria-derived oxidative stress using isoform-specific NOX inhibitors and mitochondrial ROS scavengers, as well as drugs that improve mitochondrial dynamics and metabolism to treat persistent AF and its transition to permanent AF.
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Affiliation(s)
- Roberto Ramos-Mondragón
- Department of Pharmacology, University of Michigan, 1150 West Medical Center Drive, 2301 Medical Science Research Building III, Ann Arbor, MI 48109, USA; (R.R.-M.); (L.L.I.)
| | - Andrey Lozhkin
- Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI 48019, USA; (A.L.); (A.E.V.); (M.S.R.)
| | - Aleksandr E. Vendrov
- Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI 48019, USA; (A.L.); (A.E.V.); (M.S.R.)
| | - Marschall S. Runge
- Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI 48019, USA; (A.L.); (A.E.V.); (M.S.R.)
| | - Lori L. Isom
- Department of Pharmacology, University of Michigan, 1150 West Medical Center Drive, 2301 Medical Science Research Building III, Ann Arbor, MI 48109, USA; (R.R.-M.); (L.L.I.)
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Nageswara R. Madamanchi
- Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI 48019, USA; (A.L.); (A.E.V.); (M.S.R.)
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7
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Keefe JA, Hulsurkar MM, Reilly S, Wehrens XHT. Mouse models of spontaneous atrial fibrillation. Mamm Genome 2023; 34:298-311. [PMID: 36173465 PMCID: PMC10898345 DOI: 10.1007/s00335-022-09964-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 09/20/2022] [Indexed: 11/30/2022]
Abstract
Atrial fibrillation (AF) is the most common arrhythmia in adults, with a prevalence increasing with age. Current clinical management of AF is focused on tertiary prevention (i.e., treating the symptoms and sequelae) rather than addressing the underlying molecular pathophysiology. Robust animal models of AF, particularly those that do not require supraphysiologic stimuli to induce AF (i.e., showing spontaneous AF), enable studies that can uncover the underlying mechanisms of AF. Several mouse models of AF have been described to exhibit spontaneous AF, but pathophysiologic drivers of AF differ among models. Here, we describe relevant AF mechanisms and provide an overview of large and small animal models of AF. We then provide an in-depth review of the spontaneous mouse models of AF, highlighting the relevant AF mechanisms for each model.
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Affiliation(s)
- Joshua A Keefe
- Cardiovascular Research Institute, Baylor College of Medicine, One Baylor Plaza, BCM335, Houston, TX, 77030, USA
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Mohit M Hulsurkar
- Cardiovascular Research Institute, Baylor College of Medicine, One Baylor Plaza, BCM335, Houston, TX, 77030, USA
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Svetlana Reilly
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, One Baylor Plaza, BCM335, Houston, TX, 77030, USA.
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77030, USA.
- Department of Medicine, Baylor College of Medicine, Houston, TX, 77030, USA.
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, 77030, USA.
- Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA.
- Center for Space Medicine, Baylor College of Medicine, Houston, TX, 77030, USA.
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8
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Hwang D, Liu X, Rosenberg C, Lee A, Borle S, Ricafrente JQ, Wei J, Shufelt C, Chen LS, Li X, Goldhaber JI, Bairey Merz CN, Chen PS. Sympathetic toggled sinus rate acceleration as a mechanism of sustained sinus tachycardia in chronic orthostatic intolerance syndrome. Heart Rhythm 2022; 19:2086-2094. [PMID: 35995322 DOI: 10.1016/j.hrthm.2022.08.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 08/09/2022] [Accepted: 08/11/2022] [Indexed: 12/14/2022]
Abstract
BACKGROUND The role of sympathetic nerve activity to maintain sinus rate acceleration remains unclear. OBJECTIVE The purpose of this study was to test the hypothesis that sustained (>30 seconds) sinus rate acceleration can be associated with either a sympathetic driven or a sympathetic toggled mechanism. METHODS We used a patch monitor to record skin sympathetic nerve activity (SKNA) and electrocardiogram over 24 hours. Study 1 included chronic orthostatic intolerance (OI) (n = 18), atrial fibrillation (n = 7), and asymptomatic normal control (n = 19) groups. Study 2 included 17 participants with chronic OI not treated with ivabradine, pyridostigmine, or β-blockers. RESULTS While a majority of sinus rate acceleration was driven by persistent SKNA in study 1, some episodes were toggled on and off by SKNA bursts without persistent SKNA elevation. The sympathetic toggled sinus rate acceleration episodes were found in 7 of 18 participants with chronic OI (39%), 2 of 7 participants with atrial fibrillation (29%), and 6 of 19 normal control participants (32%) (P = .847) and were faster and longer in the chronic OI group than in other groups. In study 2, there were a total of 11 episodes of sinus rate acceleration that persisted for >200 seconds. Among these episodes, 6 (35%) were toggled on and off by SKNA bursts. CONCLUSION Sustained sinus rate acceleration (may be toggled on or off) is associated with SKNA bursts in participants with chronic OI, participants with atrial fibrillation, and normal controls. Patients with OI had more frequent and longer episodes than did other groups.
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Affiliation(s)
- Daerin Hwang
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Xiao Liu
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Carine Rosenberg
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Andrew Lee
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Sanjana Borle
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Joselyn Q Ricafrente
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Janet Wei
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California; Barbra Streisand Women's Heart Center, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Chrisandra Shufelt
- Barbra Streisand Women's Heart Center, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California; Division of General Internal Medicine, Mayo Clinic, Jacksonville, Florida
| | - Lan S Chen
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Xiaochun Li
- Department of Biostatistics and Health Data Science, Indiana University School of Medicine, Richard M. Fairbanks School of Public Health, Indianapolis, Indiana
| | - Joshua I Goldhaber
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - C Noel Bairey Merz
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California; Barbra Streisand Women's Heart Center, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Peng-Sheng Chen
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California.
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Dai C, Kong B, Shuai W, Xiao Z, Qin T, Fang J, Gong Y, Zhu J, Liu Q, Fu H, Meng H, Huang H. Dapagliflozin reduces pulmonary vascular damage and susceptibility to atrial fibrillation in right heart disease. ESC Heart Fail 2022; 10:578-593. [PMID: 36369767 PMCID: PMC9871681 DOI: 10.1002/ehf2.14169] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 08/13/2022] [Accepted: 09/15/2022] [Indexed: 11/13/2022] Open
Abstract
AIMS Sodium-glucose cotransporter 2 inhibitors (SGLT2is) have made considerable progress in the field of heart failure, but their application in arrhythmia remains to be in-depth. Right heart disease (RHD) often leads to right heart dysfunction and is associated with atrial fibrillation (AF). Here, we explored the possible electrophysiologic effect of dapagliflozin (a type of SGLT2is) in the development of AF in rats with RHD. METHODS AND RESULTS Rats in the experimental group were intraperitoneally injected with a single dose of 60 mg/kg monocrotaline (MCT group, n = 32) on the first day of the experiment, whereas rats in the control group were injected with vehicle (CTL group, n = 32). Rats in the treatment subgroup were treated with dapagliflozin solution orally (MCT + DAPA and CTL + DAPA groups) for a total of 4 weeks, whereas rats in the rest of subgroups were given sterile drinking water. After 4 weeks, echocardiography demonstrated that MCT group rats developed obvious pulmonary arterial hypertension and right heart dysfunction. In addition, there were also obvious inflammatory infiltration, fibrosis, and muscularization in right atrial and pulmonary arteries. The P-wave duration (17.00 ± 0.53 ms, vs. 14.43 ± 0.57 ms in CTL; 14.00 ± 0.65 ms in CTL + DAPA; 14.57 ± 0.65 ms in MCT + DAPA; P < 0.05), RR interval (171.60 ± 1.48 ms, vs. 163.10 ± 1.10 ms in CTL; 163.30 ± 1.19 ms in CTL + DAPA; 163.10 ± 1.50 ms in MCT + DAPA; P < 0.05), Tpeak-Tend interval (65.93 ± 2.55 ms, vs. 49.55 ± 1.71 ms in CTL; 48.27 ± 3.08 ms in CTL + DAPA; P < 0.05), and corrected QT interval (200.90 ± 2.40 ms, vs. 160.00 ± 0.82 ms in CTL; 160.40 ± 1.36 ms in CTL + DAPA; 176.6 ± 1.57 ms in MCT + DAPA; P < 0.01) were significantly prolonged in the MCT group after 4 weeks, whereas P-wave amplitude (0.07 ± 0.0011 mV, vs. 0.14 ± 0.0009 mV in CTL; 0.14 ± 0.0011 mV in CTL + DAPA; 0.08 ± 0.0047 mV in MCT + DAPA; P < 0.05) and T-wave amplitude (0.04 ± 0.002 mV, vs. 0.13 ± 0.003 mV in CTL; 0.13 ± 0.003 mV in CTL + DAPA; P < 0.01) were decreased, and atrial 90% action potential duration (47.50 ± 0.93 ms, vs. 59.13 ± 2.1 ms in CTL; 59.75 ± 1.13 ms in CTL + DAPA; 60.63 ± 1.07 ms in MCT + DAPA; P < 0.01) and effective refractory periods (41.14 ± 0.88 ms, vs. 62.86 ± 0.99 ms in CTL; 63.14 ± 0.67 ms in CTL + DAPA; 54.86 ± 0.70 ms in MCT + DAPA; P < 0.01) were shortened. Importantly, the inducibility rate (80%, vs. 0% in CTL; 10% in CTL + DAPA; 40% in MCT + DAPA; P < 0.05) and duration of AF (30.85 ± 22.90 s, vs. 0 ± 0 s in CTL; 0.24 ± 0.76 s in CTL + DAPA; 5.08 ± 7.92 s in MCT + DAPA; P < 0.05) were significantly increased, whereas the expression levels of cardiac ion channels and calcium-handling proteins such as potassium/calcium channels and calmodulin were decreased. Mechanistically, 'NACHT, LRR, and PYD domain-containing protein 3' inflammasome-related pathway was significantly activated in the MCT group. Nevertheless, in the MCT + DAPA group, the above abnormalities were significantly improved. CONCLUSIONS Dapagliflozin reduces pulmonary vascular damage and right heart dysfunction, as well as the susceptibility to AF in RHD rats.
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Affiliation(s)
- Chang Dai
- Department of CardiologyRenmin Hospital of Wuhan University238 Jiefang Road430060WuhanHubeiP.R. China,Cardiovascular Research Institute of Wuhan UniversityWuhanHubeiP.R. China,Hubei Key Laboratory of CardiologyWuhanHubeiP.R. China
| | - Bin Kong
- Department of CardiologyRenmin Hospital of Wuhan University238 Jiefang Road430060WuhanHubeiP.R. China,Cardiovascular Research Institute of Wuhan UniversityWuhanHubeiP.R. China,Hubei Key Laboratory of CardiologyWuhanHubeiP.R. China
| | - Wei Shuai
- Department of CardiologyRenmin Hospital of Wuhan University238 Jiefang Road430060WuhanHubeiP.R. China,Cardiovascular Research Institute of Wuhan UniversityWuhanHubeiP.R. China,Hubei Key Laboratory of CardiologyWuhanHubeiP.R. China
| | - Zheng Xiao
- Department of CardiologyRenmin Hospital of Wuhan University238 Jiefang Road430060WuhanHubeiP.R. China,Cardiovascular Research Institute of Wuhan UniversityWuhanHubeiP.R. China,Hubei Key Laboratory of CardiologyWuhanHubeiP.R. China
| | - Tianyou Qin
- Department of CardiologyRenmin Hospital of Wuhan University238 Jiefang Road430060WuhanHubeiP.R. China,Cardiovascular Research Institute of Wuhan UniversityWuhanHubeiP.R. China,Hubei Key Laboratory of CardiologyWuhanHubeiP.R. China
| | - Jin Fang
- Department of CardiologyRenmin Hospital of Wuhan University238 Jiefang Road430060WuhanHubeiP.R. China,Cardiovascular Research Institute of Wuhan UniversityWuhanHubeiP.R. China,Hubei Key Laboratory of CardiologyWuhanHubeiP.R. China
| | - Yang Gong
- Department of CardiologyRenmin Hospital of Wuhan University238 Jiefang Road430060WuhanHubeiP.R. China,Cardiovascular Research Institute of Wuhan UniversityWuhanHubeiP.R. China,Hubei Key Laboratory of CardiologyWuhanHubeiP.R. China
| | - Jun Zhu
- Department of CardiologyRenmin Hospital of Wuhan University238 Jiefang Road430060WuhanHubeiP.R. China,Cardiovascular Research Institute of Wuhan UniversityWuhanHubeiP.R. China,Hubei Key Laboratory of CardiologyWuhanHubeiP.R. China
| | - Qi Liu
- Department of CardiologyRenmin Hospital of Wuhan University238 Jiefang Road430060WuhanHubeiP.R. China,Cardiovascular Research Institute of Wuhan UniversityWuhanHubeiP.R. China,Hubei Key Laboratory of CardiologyWuhanHubeiP.R. China
| | - Hui Fu
- Department of CardiologyRenmin Hospital of Wuhan University238 Jiefang Road430060WuhanHubeiP.R. China,Cardiovascular Research Institute of Wuhan UniversityWuhanHubeiP.R. China,Hubei Key Laboratory of CardiologyWuhanHubeiP.R. China
| | - Hong Meng
- Department of CardiologyRenmin Hospital of Wuhan University238 Jiefang Road430060WuhanHubeiP.R. China,Cardiovascular Research Institute of Wuhan UniversityWuhanHubeiP.R. China,Hubei Key Laboratory of CardiologyWuhanHubeiP.R. China
| | - He Huang
- Department of CardiologyRenmin Hospital of Wuhan University238 Jiefang Road430060WuhanHubeiP.R. China,Cardiovascular Research Institute of Wuhan UniversityWuhanHubeiP.R. China,Hubei Key Laboratory of CardiologyWuhanHubeiP.R. China
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10
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Saxena P, Myles RC, Smith GL, Workman AJ. Adrenoceptor sub-type involvement in Ca 2+ current stimulation by noradrenaline in human and rabbit atrial myocytes. Pflugers Arch 2022; 474:1311-1321. [PMID: 36131146 DOI: 10.1007/s00424-022-02746-z] [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: 05/23/2022] [Revised: 08/17/2022] [Accepted: 09/02/2022] [Indexed: 10/14/2022]
Abstract
Atrial fibrillation (AF) from elevated adrenergic activity may involve increased atrial L-type Ca2+ current (ICaL) by noradrenaline (NA). However, the contribution of the adrenoceptor (AR) sub-types to such ICaL-increase is poorly understood, particularly in human. We therefore investigated effects of various broad-action and sub-type-specific α- and β-AR antagonists on NA-stimulated atrial ICaL. ICaL was recorded by whole-cell-patch clamp at 37 °C in myocytes isolated enzymatically from atrial tissues from consenting patients undergoing elective cardiac surgery and from rabbits. NA markedly increased human atrial ICaL, maximally by ~ 2.5-fold, with EC75 310 nM. Propranolol (β1 + β2-AR antagonist, 0.2 microM) substantially decreased NA (310 nM)-stimulated ICaL, in human and rabbit. Phentolamine (α1 + α2-AR antagonist, 1 microM) also decreased NA-stimulated ICaL. CGP20712A (β1-AR antagonist, 0.3 microM) and prazosin (α1-AR antagonist, 0.5 microM) each decreased NA-stimulated ICaL in both species. ICI118551 (β2-AR antagonist, 0.1 microM), in the presence of NA + CGP20712A, had no significant effect on ICaL in human atrial myocytes, but increased it in rabbit. Yohimbine (α2-AR antagonist, 10 microM), with NA + prazosin, had no significant effect on human or rabbit ICaL. Stimulation of atrial ICaL by NA is mediated, based on AR sub-type antagonist responses, mainly by activating β1- and α1-ARs in both human and rabbit, with a β2-inhibitory contribution evident in rabbit, and negligible α2 involvement in either species. This improved understanding of AR sub-type contributions to noradrenergic activation of atrial ICaL could help inform future potential optimisation of pharmacological AR-antagonism strategies for inhibiting adrenergic AF.
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Affiliation(s)
- Priyanka Saxena
- Institute of Cardiovascular & Medical Sciences, College of Medical, Veterinary & Life Sciences, University of Glasgow, 126 University Place, Glasgow, G12 8TA, UK
| | - Rachel C Myles
- Institute of Cardiovascular & Medical Sciences, College of Medical, Veterinary & Life Sciences, University of Glasgow, 126 University Place, Glasgow, G12 8TA, UK
| | - Godfrey L Smith
- Institute of Cardiovascular & Medical Sciences, College of Medical, Veterinary & Life Sciences, University of Glasgow, 126 University Place, Glasgow, G12 8TA, UK
| | - Antony J Workman
- Institute of Cardiovascular & Medical Sciences, College of Medical, Veterinary & Life Sciences, University of Glasgow, 126 University Place, Glasgow, G12 8TA, UK.
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11
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Gonano LA, Mattiazzi A. Targeting late ICaL to close the window to ventricular arrhythmias. J Gen Physiol 2021; 153:212726. [PMID: 34699586 PMCID: PMC8552155 DOI: 10.1085/jgp.202113009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Affiliation(s)
- Luis A Gonano
- Centro de Investigaciones Cardiovasculares Horacio Cingolani, CONICET La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Alicia Mattiazzi
- Centro de Investigaciones Cardiovasculares Horacio Cingolani, CONICET La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
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12
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Zhang L, Wang X, Huang C. A narrative review of non-coding RNAs in atrial fibrillation: potential therapeutic targets and molecular mechanisms. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:1486. [PMID: 34734038 PMCID: PMC8506732 DOI: 10.21037/atm-21-4483] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 09/16/2021] [Indexed: 11/11/2022]
Abstract
Objective This review summarizes the advances in the study of ncRNAs and atrial remodeling mechanisms to explore potential therapeutic targets and strategies for AF. Background Atrial fibrillation (AF) is one of the most common arrhythmias, and its morbidity and mortality rates are gradually increasing. Non-coding ribonucleic acid RNAs (ncRNAs) are transcribed from the genome and do not have the ability to be translated into proteins. A growing body of evidence has shown ncRNAs are extensively involved in the pathophysiological processes underlying AF. However, the precise molecular mechanisms of these associations have not been fully elucidated. Atrial remodeling plays a key role in the occurrence and development of AF, and includes electrical remodeling, structural remodeling, and autonomic nerve remodeling. Research has shown that ncRNA expression is altered in the plasma and tissues of AF patients that mediate cardiac excitation and arrhythmia, and is closely related to atrial remodeling. Methods Literatures about ncRNAs and atrial fibrillation were extensively reviewed to discuss and analyze. Conclusions The biology of ncRNAs represents a relatively new field of research and is still in an emerging stage. Recent studies have laid a foundation for understanding the molecular mechanisms of AF, future studies aimed at identifying how ncRNAs act on atrial fibrillation to provide potentially promising therapeutic targets for the treatment of atrial fibrillation.
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Affiliation(s)
- Lan Zhang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Xi Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Congxin Huang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
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13
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Investigational Anti-Atrial Fibrillation Pharmacology and Mechanisms by Which Antiarrhythmics Terminate the Arrhythmia: Where Are We in 2020? J Cardiovasc Pharmacol 2021; 76:492-505. [PMID: 33165131 PMCID: PMC7641178 DOI: 10.1097/fjc.0000000000000892] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Antiarrhythmic drugs remain the mainstay therapy for patients with atrial fibrillation (AF). A major disadvantage of the currently available anti-AF agents is the risk of induction of ventricular proarrhythmias. Aiming to reduce this risk, several atrial-specific or -selective ion channel block approaches have been introduced for AF suppression, but only the atrial-selective inhibition of the sodium channel has been demonstrated to be valid in both experimental and clinical studies. Among the other pharmacological anti-AF approaches, “upstream therapy” has been prominent but largely disappointing, and pulmonary delivery of anti-AF drugs seems to be promising. Major contradictions exist in the literature about the electrophysiological mechanisms of AF (ie, reentry or focal?) and the mechanisms by which anti-AF drugs terminate AF, making the search for novel anti-AF approaches largely empirical. Drug-induced termination of AF may or may not be associated with prolongation of the atrial effective refractory period. Anti-AF drug research has been largely based on the “suppress reentry” ideology; however, results of the AF mapping studies increasingly indicate that nonreentrant mechanism(s) plays an important role in the maintenance of AF. Also, the analysis of anti-AF drug-induced electrophysiological alterations during AF, conducted in the current study, leans toward the focal source as the prime mechanism of AF maintenance. More effort should be placed on the investigation of pharmacological suppression of the focal mechanisms.
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14
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Nasser NH, Simri MM, Bishara NK, Habib MG, Nasir NN. Children with heart transplants: Lessons learned from 774 visits at a primary community clinic. Pediatr Transplant 2020; 24:e13617. [PMID: 31880042 DOI: 10.1111/petr.13617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 10/05/2019] [Accepted: 10/29/2019] [Indexed: 11/30/2022]
Abstract
Aims Unexpected decompensation of PHTRs may surprise, when the patient is at home. If the PHTR lives a distance from transplant center, the task of identifying risk factors of allograft rejection/dysfunction falls primarily on the PCP in the PCC, whether or not they are knowledgeable toward pediatric heart-transplantation. Methods We reviewed the medical reports of three heart-transplanted children in our periphery clinic between the years 2005 and 2019. Results The unexpected death of one patient, hours after he left our health facility, was the impetus for writing this article. Another heart transplant child attended our periphery clinic for 774 visits. Majority of visits were casual, others were scheduled, and the rest were for administrative affairs. We referred the PHTR to the transplantation center in 9% of all visits. In remaining 91% visits, we handled problems locally. Conclusions One of the important lessons we have learned through handling the PHTR at the PCC is that, during daily workflows and dealing with the occasional visits of a heart transplant child, related critical clinical information to allograft rejection or its dysfunction can easily evade from awareness of the attending physician. Through this study, we demonstrated that a program of summoning the PHTR to "initiated monthly visits" at the PCC enables the PCP to be maximally aware of critical clinical information, in addition to limiting futile referrals of 91% of the visits to specialized centers, without adversely affecting the prognosis.
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Affiliation(s)
- Nadim H Nasser
- Clalit Health Organization, Haifa, Israel.,Faculty of Medicine, Bar-Ilan University, Ramat Gan, Israel
| | | | | | - Mona G Habib
- A Pediatric Neurologist at Pediatric Neurology Unit, Rambam Medical Center, Haifa, Israel
| | - Nadir N Nasir
- General Surgery Department, Ulm University Hospital, Ulm, Germany
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15
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Garg P, Garg V, Shrestha R, Sanguinetti MC, Kamp TJ, Wu JC. Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes as Models for Cardiac Channelopathies: A Primer for Non-Electrophysiologists. Circ Res 2019; 123:224-243. [PMID: 29976690 DOI: 10.1161/circresaha.118.311209] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Life threatening ventricular arrhythmias leading to sudden cardiac death are a major cause of morbidity and mortality. In the absence of structural heart disease, these arrhythmias, especially in the younger population, are often an outcome of genetic defects in specialized membrane proteins called ion channels. In the heart, exceptionally well-orchestrated activity of a diversity of ion channels mediates the cardiac action potential. Alterations in either the function or expression of these channels can disrupt the configuration of the action potential, leading to abnormal electrical activity of the heart that can sometimes initiate an arrhythmia. Understanding the pathophysiology of inherited arrhythmias can be challenging because of the complexity of the disorder and lack of appropriate cellular and in vivo models. Recent advances in human induced pluripotent stem cell technology have provided remarkable progress in comprehending the underlying mechanisms of ion channel disorders or channelopathies by modeling these complex arrhythmia syndromes in vitro in a dish. To fully realize the potential of induced pluripotent stem cells in elucidating the mechanistic basis and complex pathophysiology of channelopathies, it is crucial to have a basic knowledge of cardiac myocyte electrophysiology. In this review, we will discuss the role of the various ion channels in cardiac electrophysiology and the molecular and cellular mechanisms of arrhythmias, highlighting the promise of human induced pluripotent stem cell-cardiomyocytes as a model for investigating inherited arrhythmia syndromes and testing antiarrhythmic strategies. Overall, this review aims to provide a basic understanding of the electrical activity of the heart and related channelopathies, especially to clinicians or research scientists in the cardiovascular field with limited electrophysiology background.
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Affiliation(s)
- Priyanka Garg
- From the Stanford Cardiovascular Institute (P.G., R.S., J.C.W.).,Department of Medicine, Division of Cardiology (P.G., R.S., J.C.W.).,Institute for Stem Cell Biology and Regenerative Medicine (P.G., R.S., J.C.W.)
| | - Vivek Garg
- Stanford University School of Medicine, CA; Department of Physiology, University of California San Francisco (V.G.)
| | - Rajani Shrestha
- From the Stanford Cardiovascular Institute (P.G., R.S., J.C.W.).,Department of Medicine, Division of Cardiology (P.G., R.S., J.C.W.).,Institute for Stem Cell Biology and Regenerative Medicine (P.G., R.S., J.C.W.)
| | | | - Timothy J Kamp
- Department of Medicine, University of Wisconsin-Madison (T.J.K.)
| | - Joseph C Wu
- From the Stanford Cardiovascular Institute (P.G., R.S., J.C.W.) .,Department of Medicine, Division of Cardiology (P.G., R.S., J.C.W.).,Institute for Stem Cell Biology and Regenerative Medicine (P.G., R.S., J.C.W.)
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16
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Kettlewell S, Saxena P, Dempster J, Colman MA, Myles RC, Smith GL, Workman AJ. Dynamic clamping human and rabbit atrial calcium current: narrowing I CaL window abolishes early afterdepolarizations. J Physiol 2019; 597:3619-3638. [PMID: 31093979 PMCID: PMC6767690 DOI: 10.1113/jp277827] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 05/13/2019] [Indexed: 11/08/2022] Open
Abstract
Key points Early‐afterdepolarizations (EADs) are abnormal action potential oscillations and a known cause of cardiac arrhythmias. Ventricular EADs involve reactivation of a Ca2+ current (ICaL) in its ‘window region’ voltage range. However, electrical mechanisms of atrial EADs, a potential cause of atrial fibrillation, are poorly understood. Atrial cells were obtained from consenting patients undergoing heart surgery, as well as from rabbits. ICaL was blocked with nifedipine and then a hybrid patch clamp/mathematical‐modelling technique, ‘dynamic clamping’, was used to record action potentials at the same time as injecting an artificial, modifiable, ICaL (ICaL,D‐C). Progressively widening the ICaL,D‐C window region produced EADs of various types, dependent on window width. EAD production was strongest upon moving the activation (vs. inactivation) side of the window. EADs were then induced by a different method: increasing ICaL,D‐C amplitude and/or K+ channel‐blockade (4‐aminopyridine). Narrowing of the ICaL,D‐C window by ∼10 mV abolished these EADs. Atrial ICaL window narrowing is worthy of further testing as a potential anti‐atrial fibrillation drug mechanism.
Abstract Atrial early‐afterdepolarizations (EADs) may contribute to atrial fibrillation (AF), perhaps involving reactivation of L‐type Ca2+ current (ICaL) in its window region voltage range. The present study aimed (i) to validate the dynamic clamp technique for modifying the ICaL contribution to atrial action potential (AP) waveform; (ii) to investigate the effects of widening the window ICaL on EAD‐propensity; and (iii) to test whether EADs from increased ICaL and AP duration are supressed by narrowing the window ICaL. ICaL and APs were recorded from rabbit and human atrial myocytes by whole‐cell‐patch clamp. During AP recording, ICaL was inhibited (3 µm nifedipine) and replaced by a dynamic clamp model current, ICaL,D‐C (tuned to native ICaL characteristics), computed in real‐time (every 50 µs) based on myocyte membrane potential. ICaL,D‐C‐injection restored the nifedipine‐suppressed AP plateau. Widening the window ICaL,D‐C, symmetrically by stepwise simultaneous equal shifts of half‐voltages (V0.5) of ICaL,D‐C activation (negatively) and inactivation (positively), generated EADs (single, multiple or preceding repolarization failure) in a window width‐dependent manner, as well as AP alternans. A stronger EAD‐generating effect resulted from independently shifting activation V0.5 (asymmetrical widening) than inactivation V0.5; for example, a 15 mV activation shift produced EADs in nine of 17 (53%) human atrial myocytes vs. 0 of 18 from inactivation shift (P < 0.05). In 11 rabbit atrial myocytes in which EADs were generated either by increasing the conductance of normal window width ICaL,D‐C or subsequent 4‐aminopyridine (2 mm), window ICaL,D‐C narrowing (10 mV) abolished EADs of all types (P < 0.05). The present study validated the dynamic clamp for ICaL, which is novel in atrial cardiomyocytes, and showed that EADs of various types are generated by widening (particularly asymmetrically) the window ICaL, as well as abolished by narrowing it. Window ICaL narrowing is a potential therapeutic mechanism worth pursuing in the search for improved anti‐AF drugs. Early‐afterdepolarizations (EADs) are abnormal action potential oscillations and a known cause of cardiac arrhythmias. Ventricular EADs involve reactivation of a Ca2+ current (ICaL) in its ‘window region’ voltage range. However, electrical mechanisms of atrial EADs, a potential cause of atrial fibrillation, are poorly understood. Atrial cells were obtained from consenting patients undergoing heart surgery, as well as from rabbits. ICaL was blocked with nifedipine and then a hybrid patch clamp/mathematical‐modelling technique, ‘dynamic clamping’, was used to record action potentials at the same time as injecting an artificial, modifiable, ICaL (ICaL,D‐C). Progressively widening the ICaL,D‐C window region produced EADs of various types, dependent on window width. EAD production was strongest upon moving the activation (vs. inactivation) side of the window. EADs were then induced by a different method: increasing ICaL,D‐C amplitude and/or K+ channel‐blockade (4‐aminopyridine). Narrowing of the ICaL,D‐C window by ∼10 mV abolished these EADs. Atrial ICaL window narrowing is worthy of further testing as a potential anti‐atrial fibrillation drug mechanism.
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Affiliation(s)
- Sarah Kettlewell
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow, UK
| | - Priyanka Saxena
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow, UK
| | - John Dempster
- Strathclyde Institute of Pharmacy & Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | | | - Rachel C Myles
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow, UK
| | - Godfrey L Smith
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow, UK
| | - Antony J Workman
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow, UK
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17
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Chang CJ, Li SJ, Chen YC, Huang SY, Chen SA, Chen YJ. Histone deacetylase inhibition attenuates atrial arrhythmogenesis in sterile pericarditis. Transl Res 2018; 200:54-64. [PMID: 30670155 DOI: 10.1016/j.trsl.2018.06.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Revised: 06/06/2018] [Accepted: 06/06/2018] [Indexed: 10/14/2022]
Abstract
Cardiac surgery is complicated with atrial fibrillation (AF). Histone deacetylase (HDAC) inhibition reduces AF occurrence. In pericarditis, HDAC inhibition may modulate AF trigger and substrate. We recorded electrocardiograms in control and pericardiotomic (op) rabbits without and with an intraperitoneal injection of MPT0E014 (HDAC inhibitor). Conventional microelectrodes recorded action potentials (APs) in pulmonary veins (PVs), the right and left atrium (LA). Masson's trichrome was used to identify collagen fibers in PVs and the LA. Electrocardiograms showed frequent atrial premature contractions in op rabbits, but not in the other 3 groups. The beating rates in PVs and opPVs were decreased by MPT0E014 treatment. Spontaneous burst firings occurred in opPVs (36.4%), but not in control PVs. H2O2 induced greater burst firings in opPVs (72.7%) than in control PVs (11.1%), MPT0E014-treated PVs (16.7%), and MPT0E014-treated opPVs (12.5%). The AP duration at a repolarization extent of 90% (APD90) was shorter in the opLA than that in the control LA. In the presence of isoproterenol (1 μM), rapid atrial pacing (RAP, 20 Hz) induced a higher incidence of burst firings in the opLA (90%) than in the other groups. In contrast, acetylcholine (5 mM) and RAP induced a lower incidence of burst firing in the MPT0E014-treated LA (33.3%) than in the other groups. Fibrosis prevailed in opPVs and the opLA compared to the respective control PVs and LA, which was attenuated in those that received MPT0E014. In conclusion, a pericardiotomy increased fibrosis and arrhythmogenesis in PVs and the LA, which were prevented by HDAC inhibition.
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Affiliation(s)
- Chien-Jung Chang
- Division of Cardiology, Tungs' Taichung MetroHarbor Hospital, Taichung, Taiwan
| | - Shao-Jung Li
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Division of Cardiovascular Surgery, Department of Surgery, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Yao-Chang Chen
- Department of Biomedical Engineering and Institute of Physiology, National Defense Medical Center, Taipei, Taiwan
| | - Shih-Yu Huang
- Division of Cardiology, Department of Internal Medicine, Cathay General Hospital, Taipei, Taiwan
| | - Shih-Ann Chen
- National Yang-Ming University, School of Medicine, Taipei, Taiwan; Division of Cardiology and Cardiovascular Research Center, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Yi-Jen Chen
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Division of Cardiovascular Medicine, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan.
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Calvo D, Filgueiras-Rama D, Jalife J. Mechanisms and Drug Development in Atrial Fibrillation. Pharmacol Rev 2018; 70:505-525. [PMID: 29921647 PMCID: PMC6010660 DOI: 10.1124/pr.117.014183] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation is a highly prevalent cardiac arrhythmia and the most important cause of embolic stroke. Although genetic studies have identified an increasing assembly of AF-related genes, the impact of these genetic discoveries is yet to be realized. In addition, despite more than a century of research and speculation, the molecular and cellular mechanisms underlying AF have not been established, and therapy for AF, particularly persistent AF, remains suboptimal. Current antiarrhythmic drugs are associated with a significant rate of adverse events, particularly proarrhythmia, which may explain why many highly symptomatic AF patients are not receiving any rhythm control therapy. This review focuses on recent advances in AF research, including its epidemiology, genetics, and pathophysiological mechanisms. We then discuss the status of antiarrhythmic drug therapy for AF today, reviewing molecular mechanisms, and the possible clinical use of some of the new atrial-selective antifibrillatory agents, as well as drugs that target atrial remodeling, inflammation and fibrosis, which are being tested as upstream therapies to prevent AF perpetuation. Altogether, the objective is to highlight the magnitude and endemic dimension of AF, which requires a significant effort to develop new and effective antiarrhythmic drugs, but also improve AF prevention and treatment of risk factors that are associated with AF complications.
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Affiliation(s)
- David Calvo
- Department of Cardiology, Arrhythmia Unit, Hospital Universitario Central de Asturias and Instituto de Investigación Sanitaria del Principado de Asturias, Oviedo, Spain (D.C.); Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain (D.F.-R., J.J.); Department of Cardiology, Arrhythmia Unit, Hospital Clínico Universitario San Carlos, Madrid, Spain (D.F.-R.); Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain (D.F.-R., J.J.); and Center for Arrhythmia Research, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan (J.J.)
| | - David Filgueiras-Rama
- Department of Cardiology, Arrhythmia Unit, Hospital Universitario Central de Asturias and Instituto de Investigación Sanitaria del Principado de Asturias, Oviedo, Spain (D.C.); Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain (D.F.-R., J.J.); Department of Cardiology, Arrhythmia Unit, Hospital Clínico Universitario San Carlos, Madrid, Spain (D.F.-R.); Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain (D.F.-R., J.J.); and Center for Arrhythmia Research, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan (J.J.)
| | - José Jalife
- Department of Cardiology, Arrhythmia Unit, Hospital Universitario Central de Asturias and Instituto de Investigación Sanitaria del Principado de Asturias, Oviedo, Spain (D.C.); Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain (D.F.-R., J.J.); Department of Cardiology, Arrhythmia Unit, Hospital Clínico Universitario San Carlos, Madrid, Spain (D.F.-R.); Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain (D.F.-R., J.J.); and Center for Arrhythmia Research, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan (J.J.)
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19
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Yin X, Zhao Z, Gao L, Chang D, Xiao X, Zhang R, Chen Q, Cheng J, Yang Y, Xi Y, Xia Y. Frequency Gradient Within Coronary Sinus Predicts the Long-Term Outcome of Persistent Atrial Fibrillation Catheter Ablation. J Am Heart Assoc 2017; 6:JAHA.116.004869. [PMID: 28255079 PMCID: PMC5524018 DOI: 10.1161/jaha.116.004869] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Background The coronary sinus (CS), as a junction of the atria, contributes to atrial fibrillation (AF) by developing unstable reentry, and isolating the atria by ablation at the CS could terminate AF. The present study evaluated whether AF activities at the CS in a subset of patients contributed to AF maintenance and predicted clinical outcome of ablation. Methods and Results We studied 122 consecutive patients who had a first‐time radiofrequency ablation for persistent AF. Bipolar electrograms were obtained from multiple regions of the left atrium by a Lasso mapping catheter before ablation. Pulmonary vein isolation terminated AF in 12 patients (9.8%). Sequential stepwise ablation was conducted in pulmonary vein isolation nontermination patients and succeeded in 22 patients (18%). In the stepwise termination group, AF frequency in the proximal CS (CSp) was significantly higher (10.2±2.1 Hz versus 8.3±1.8 Hz, P<0.001), and the ratio of distal CS (CSd) to proximal CS (CSd/CSp ratio, 56.6%±10.11% versus 70.7%±9.8%, P<0.001) was significantly lower than that in the nontermination group. The stepwise logistic regression analysis indicated that the CSd/CSp ratio was an independent predictor with an odds ratio of 1.131 (95%CI 1.053‐1.214; P=0.001). With a cutoff of 67%, the patients with lower CSd/CSp ratios had significantly better index and long‐term outcomes than those with higher ratios during a follow‐up of 46±18 months. Conclusions Rapid repetitive activities in the musculature of the proximal CS may contribute to maintenance of AF after pulmonary vein isolation alone in persistent AF. A cutoff at 67%, of the CSd/CSp frequency ratio might be an indicator to stratify the subset of patients who might benefit from CS ablation.
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Affiliation(s)
- Xiaomeng Yin
- First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Ziming Zhao
- First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Lianjun Gao
- First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Dong Chang
- First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Xianjie Xiao
- First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Rongfeng Zhang
- First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Qi Chen
- Texas Heart Institute, Houston, TX
| | | | - Yanzong Yang
- First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Yutao Xi
- Texas Heart Institute, Houston, TX
| | - Yunlong Xia
- First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
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20
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Affiliation(s)
- Aman Chugh
- From the Section of Cardiac Electrophysiology, Division of Cardiology, University of Michigan Medical Center, Ann Arbor
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21
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Boukens BJ, Coronel R, Christoffels VM. Embryonic development of the right ventricular outflow tract and arrhythmias. Heart Rhythm 2016; 13:616-22. [DOI: 10.1016/j.hrthm.2015.11.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Indexed: 12/19/2022]
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22
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Gourraud JB, Andrade JG, Macle L, Mondésert B. Pharmacological Tests in Atrial Fibrillation Ablation. Arrhythm Electrophysiol Rev 2016; 5:170-176. [PMID: 28116081 DOI: 10.15420/aer.2016:27:2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The invasive management of atrial fibrillation (AF) has been considerably changed by the identification of major sites of AF initiation and/or maintenance within the pulmonary vein antra. Percutaneous catheter ablation of these targets has become the standard of care for sustained maintenance of sinus rhythm. Long-term failure of ablation is related to an inability to create a durable transmural lesion or to identify all of the non-pulmonary vein arrhythmia triggers. Pharmacological challenges during catheter ablation have been suggested to improve outcomes in both paroxysmal and persistent AF. Herein we review the mechanism and evidence for the use of pharmacological adjuncts during the catheter ablation of AF.
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Affiliation(s)
- Jean-Baptiste Gourraud
- Electrophysiology Service, Montreal Heart Institute and University of Montreal, Montreal, Quebec, Canada
| | - Jason G Andrade
- Electrophysiology Service, Montreal Heart Institute and University of Montreal, Montreal, Quebec, Canada
| | - Laurent Macle
- Electrophysiology Service, Montreal Heart Institute and University of Montreal, Montreal, Quebec, Canada
| | - Blandine Mondésert
- Electrophysiology Service, Montreal Heart Institute and University of Montreal, Montreal, Quebec, Canada
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23
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Lozano-Velasco E, Hernández-Torres F, Daimi H, Serra SA, Herraiz A, Hove-Madsen L, Aránega A, Franco D. Pitx2 impairs calcium handling in a dose-dependent manner by modulating Wnt signalling. Cardiovasc Res 2016; 109:55-66. [PMID: 26243430 DOI: 10.1093/cvr/cvv207] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 07/16/2015] [Indexed: 01/02/2023] Open
Abstract
AIMS Atrial fibrillation (AF) is the most common type of arrhythmia in humans, yet the genetic cause of AF remains elusive. Genome-wide association studies (GWASs) have reported risk variants in four distinct genetic loci, and more recently, a meta-GWAS has further implicated six new loci in AF. However, the functional role of these AF GWAS-related genes in AF and their inter-relationship remain elusive. METHODS AND RESULTS To get further insights into the molecular mechanisms driven by Pitx2, calcium handling and novel AF GWAS-associated gene expression were analysed in two distinct Pitx2 loss-of-function models with distinct basal electrophysiological defects; a novel Pitx2 conditional mouse line, Sox2CrePitx2, and our previously reported atrial-specific NppaCrePitx2 line. Molecular analyses of the left atrial appendage in NppaCrePitx2(+/-) and NppaCrePitx2(-/-) adult mice demonstrate that AF GWAS-associated genes such as Zfhx3, Kcnn3, and Wnt8a are severely impaired but not Cav1, Synpo2l, nor Prrx1. In addition, multiple calcium-handling genes such as Atp2a2, Casq2, and Plb are severely altered in atrial-specific NppaCrePitx2 mice in a dose-dependent manner. Functional assessment of calcium homeostasis further underscores these findings. In addition, multiple AF-related microRNAs are also impaired. In vitro over-expression of Wnt8, but not Zfhx3, impairs calcium handling and modulates microRNA expression signature identified in Pitx2 loss-of-function models. CONCLUSION Our data demonstrate a dose-dependent relation between Pitx2 expression and the expression of AF susceptibility genes, calcium handling, and microRNAs and identify a complex regulatory network orchestrated by Pitx2 with large impact on atrial arrhythmogenesis susceptibility.
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Affiliation(s)
- Estefanía Lozano-Velasco
- Cardiovascular Development Group, Department of Experimental Biology, University of Jaén, Jaén, Spain
| | | | - Houria Daimi
- Cardiovascular Development Group, Department of Experimental Biology, University of Jaén, Jaén, Spain
| | - Selma A Serra
- Cardiac Rhythm and Contraction Group, Cardiovascular Research Centre CSIC-ICCC and IIB Sant Pau, Barcelona, Spain
| | - Adela Herraiz
- Cardiac Rhythm and Contraction Group, Cardiovascular Research Centre CSIC-ICCC and IIB Sant Pau, Barcelona, Spain
| | - Leif Hove-Madsen
- Cardiac Rhythm and Contraction Group, Cardiovascular Research Centre CSIC-ICCC and IIB Sant Pau, Barcelona, Spain
| | - Amelia Aránega
- Cardiovascular Development Group, Department of Experimental Biology, University of Jaén, Jaén, Spain
| | - Diego Franco
- Cardiovascular Development Group, Department of Experimental Biology, University of Jaén, Jaén, Spain
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Brandenburg S, Arakel EC, Schwappach B, Lehnart SE. The molecular and functional identities of atrial cardiomyocytes in health and disease. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:1882-93. [PMID: 26620800 DOI: 10.1016/j.bbamcr.2015.11.025] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 11/17/2015] [Accepted: 11/23/2015] [Indexed: 12/28/2022]
Abstract
Atrial cardiomyocytes are essential for fluid homeostasis, ventricular filling, and survival, yet their cell biology and physiology are incompletely understood. It has become clear that the cell fate of atrial cardiomyocytes depends significantly on transcription programs that might control thousands of differentially expressed genes. Atrial muscle membranes propagate action potentials and activate myofilament force generation, producing overall faster contractions than ventricular muscles. While atria-specific excitation and contractility depend critically on intracellular Ca(2+) signalling, voltage-dependent L-type Ca(2+) channels and ryanodine receptor Ca(2+) release channels are each expressed at high levels similar to ventricles. However, intracellular Ca(2+) transients in atrial cardiomyocytes are markedly heterogeneous and fundamentally different from ventricular cardiomyocytes. In addition, differential atria-specific K(+) channel expression and trafficking confer unique electrophysiological and metabolic properties. Because diseased atria have the propensity to perpetuate fast arrhythmias, we discuss our understanding about the cell-specific mechanisms that lead to metabolic and/or mitochondrial dysfunction in atrial fibrillation. Interestingly, recent work identified potential atria-specific mechanisms that lead to early contractile dysfunction and metabolic remodelling, suggesting highly interdependent metabolic, electrical, and contractile pathomechanisms. Hence, the objective of this review is to provide an integrated model of atrial cardiomyocytes, from tissue-specific cell properties, intracellular metabolism, and excitation-contraction (EC) coupling to early pathological changes, in particular metabolic dysfunction and tissue remodelling due to atrial fibrillation and aging. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.
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Affiliation(s)
- Sören Brandenburg
- Heart Research Center Göttingen, University Medical Center Göttingen, 37075 Göttingen, Germany; Department of Cardiology & Pulmonology, University Medical Center Göttingen, 37075 Göttingen, Germany
| | - Eric C Arakel
- Heart Research Center Göttingen, University Medical Center Göttingen, 37075 Göttingen, Germany; Department of Molecular Biology, University Medical Center Göttingen, 37073 Göttingen, Germany
| | - Blanche Schwappach
- Heart Research Center Göttingen, University Medical Center Göttingen, 37075 Göttingen, Germany; Department of Molecular Biology, University Medical Center Göttingen, 37073 Göttingen, Germany; German Centre for Cardiovascular Research (DZHK) site Göttingen, 37075 Göttingen, Germany
| | - Stephan E Lehnart
- Heart Research Center Göttingen, University Medical Center Göttingen, 37075 Göttingen, Germany; Department of Cardiology & Pulmonology, University Medical Center Göttingen, 37075 Göttingen, Germany; German Centre for Cardiovascular Research (DZHK) site Göttingen, 37075 Göttingen, Germany.
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25
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Association between dissociated firing in isolated pulmonary veins and the initiation and maintenance of atrial fibrillation. J Interv Card Electrophysiol 2015; 45:29-35. [DOI: 10.1007/s10840-015-0070-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 10/14/2015] [Indexed: 10/22/2022]
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26
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Fischer TH, Herting J, Mason FE, Hartmann N, Watanabe S, Nikolaev VO, Sprenger JU, Fan P, Yao L, Popov AF, Danner BC, Schöndube F, Belardinelli L, Hasenfuss G, Maier LS, Sossalla S. Late INa increases diastolic SR-Ca2+-leak in atrial myocardium by activating PKA and CaMKII. Cardiovasc Res 2015; 107:184-96. [PMID: 25990311 PMCID: PMC4476413 DOI: 10.1093/cvr/cvv153] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 04/16/2015] [Indexed: 12/19/2022] Open
Abstract
Aims Enhanced cardiac late Na current (late INa) and increased sarcoplasmic reticulum (SR)-Ca2+-leak are both highly arrhythmogenic. This study seeks to identify signalling pathways interconnecting late INa and SR-Ca2+-leak in atrial cardiomyocytes (CMs). Methods and results In murine atrial CMs, SR-Ca2+-leak was increased by the late INa enhancer Anemonia sulcata toxin II (ATX-II). An inhibition of Ca2+/calmodulin-dependent protein kinase II (Autocamide-2-related inhibitory peptide), protein kinase A (H89), or late INa (Ranolazine or Tetrodotoxin) all prevented ATX-II-dependent SR-Ca2+-leak. The SR-Ca2+-leak induction by ATX-II was not detected when either the Na+/Ca2+ exchanger was inhibited (KBR) or in CaMKIIδc-knockout mice. FRET measurements revealed increased cAMP levels upon ATX-II stimulation, which could be prevented by inhibition of adenylyl cyclases (ACs) 5 and 6 (NKY 80) but not by inhibition of phosphodiesterases (IBMX), suggesting PKA activation via an AC-dependent increase of cAMP levels. Western blots showed late INa-dependent hyperphosphorylation of CaMKII as well as PKA target sites at ryanodine receptor type-2 (-S2814 and -S2808) and phospholamban (-Thr17, -S16). Enhancement of late INa did not alter Ca2+-transient amplitude or SR-Ca2+-load. However, upon late INa activation and simultaneous CaMKII inhibition, Ca2+-transient amplitude and SR-Ca2+-load were increased, whereas PKA inhibition reduced Ca2+-transient amplitude and load and additionally slowed Ca2+ elimination. In atrial CMs from patients with atrial fibrillation, inhibition of late INa, CaMKII, or PKA reduced the SR-Ca2+-leak. Conclusion Late INa exerts distinct effects on Ca2+ homeostasis in atrial myocardium through activation of CaMKII and PKA. Inhibition of late INa represents a potential approach to attenuate CaMKII activation and decreases SR-Ca2+-leak in atrial rhythm disorders. The interconnection with the cAMP/PKA system further increases the antiarrhythmic potential of late INa inhibition.
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Affiliation(s)
- Thomas H Fischer
- Klinik für Kardiologie und Pneumologie/Herzzentrum, Georg-August-Universität Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Jonas Herting
- Klinik für Kardiologie und Pneumologie/Herzzentrum, Georg-August-Universität Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Fleur E Mason
- Klinik für Kardiologie und Pneumologie/Herzzentrum, Georg-August-Universität Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Nico Hartmann
- Klinik für Kardiologie und Pneumologie/Herzzentrum, Georg-August-Universität Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Saera Watanabe
- Klinik für Kardiologie und Pneumologie/Herzzentrum, Georg-August-Universität Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Viacheslav O Nikolaev
- Klinik für Kardiologie und Pneumologie/Herzzentrum, Georg-August-Universität Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany DZHK (German Center for Cardiovascular Research), partner site Göttingen, Göttingen, Germany
| | - Julia U Sprenger
- Klinik für Kardiologie und Pneumologie/Herzzentrum, Georg-August-Universität Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Peidong Fan
- Department of Biology, Cardiovascular, Therapeutic Area, Gilead Sciences, Foster City, CA, USA
| | - Lina Yao
- Department of Biology, Cardiovascular, Therapeutic Area, Gilead Sciences, Foster City, CA, USA
| | - Aron-Frederik Popov
- Klinik für Thorax-, Herz-, Gefäßchirurgie/Herzzentrum, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Bernhard C Danner
- Klinik für Thorax-, Herz-, Gefäßchirurgie/Herzzentrum, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Friedrich Schöndube
- Klinik für Thorax-, Herz-, Gefäßchirurgie/Herzzentrum, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Luiz Belardinelli
- Department of Biology, Cardiovascular, Therapeutic Area, Gilead Sciences, Foster City, CA, USA
| | - Gerd Hasenfuss
- Klinik für Kardiologie und Pneumologie/Herzzentrum, Georg-August-Universität Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany DZHK (German Center for Cardiovascular Research), partner site Göttingen, Göttingen, Germany
| | - Lars S Maier
- Innere Medizin II - Kardiologie, Universitätsklinikum Regensburg, Regensburg, Germany
| | - Samuel Sossalla
- Klinik für Kardiologie und Pneumologie/Herzzentrum, Georg-August-Universität Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany DZHK (German Center for Cardiovascular Research), partner site Göttingen, Göttingen, Germany
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27
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Lou Q, Belevych AE, Radwański PB, Liu B, Kalyanasundaram A, Knollmann BC, Fedorov VV, Györke S. Alternating membrane potential/calcium interplay underlies repetitive focal activity in a genetic model of calcium-dependent atrial arrhythmias. J Physiol 2014; 593:1443-58. [PMID: 25384790 DOI: 10.1113/jphysiol.2014.280784] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 10/23/2014] [Indexed: 01/09/2023] Open
Abstract
KEY POINTS Atrial fibrillation is often initiated and perpetuated by abnormal electrical pulses repetitively originating from regions outside the heart's natural pacemaker. In this study we examined the causal role of abnormal calcium releases from the sarcoplasmic reticulum in producing repetitive electrical discharges in atrial cells and tissues. Calsequestrin2 is a protein that stabilizes the closed state of calcium release channels, i.e. the ryanodine receptors. In the atria from mice predisposed to abnormal calcium releases secondary to the absence of calsequestrin2, we observed abnormal repetitive electrical discharges that may lead to atrial fibrillation. Here, we report a novel pathological rhythm generator. Specifically, abnormal calcium release leads to electrical activation, which in turn results in another abnormal calcium release. This process repeats itself and thus sustains the repetitive electrical discharges. These results suggest that improving the stability of ryanodine receptors might be useful to treat atrial fibrillation. ABSTRACT Aberrant diastolic calcium (Ca) release due to leaky ryanodine receptors (RyR2s) has been recently associated with atrial fibrillation (AF) and catecholaminergic polymorphic ventricular tachycardia (CPVT). However, it remains unclear how diastolic Ca release contributes to the rising of rapid repetitive focal activity, which is considered as a common AF triggering mechanism. To address this question, we conducted simultaneous voltage/Ca optical mapping in atrial tissue and one-/two-dimensional confocal imaging in atrial tissue and myocytes from wild-type (WT, n = 15) and CPVT mice lacking calsequestrin 2 (Casq2(-/-), n = 45), which promotes diastolic Ca release. During β-adrenergic stimulation (100 nM isoproterenol), only Casq2(-/-) atrial myocytes showed pacing-induced self-sustained repetitive activity (31 ± 21 s vs. none in WT). Importantly, in atrial tissue, this repetitive activity could translate to Ca-dependent focal arrhythmia. Ectopic action potential (AP) firing during repetitive activity occurred only when diastolic Ca release achieved a sufficient level of synchronization. The AP, in turn, synchronized subsequent diastolic Ca release by temporally aligning multiple sources of Ca waves both within individual myocytes and throughout the atrial tissue. This alternating interplay between AP and diastolic Ca release perpetuates the self-sustaining repetitive activity. In fact, pharmacological disruption of synchronized diastolic Ca release (by ryanodine) prevented aberrant APs; and vice versa, the inhibition of AP (by TTX or 0 Na, 0 Ca solution) de-synchronized diastolic Ca release. Taken together, these results suggest that a cyclical interaction between synchronized diastolic Ca release and AP forms a pathological rhythm generator that is involved in Ca-dependent atrial arrhythmias in CPVT.
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Affiliation(s)
- Qing Lou
- Department of Physiology & Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, USA; Davis Heart & Lung Research Institute, The Ohio State University, Columbus, OH, USA
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28
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FRAGAKIS NIKOLAOS, KOSKINAS KONSTANTINOSC, VASSILIKOS VASSILIOS. Ranolazine as a Promising Treatment Option for Atrial Fibrillation: Electrophysiologic Mechanisms, Experimental Evidence, and Clinical Implications. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2014; 37:1412-20. [DOI: 10.1111/pace.12486] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2014] [Revised: 06/29/2014] [Accepted: 06/30/2014] [Indexed: 11/28/2022]
Affiliation(s)
- NIKOLAOS FRAGAKIS
- Third Department of Cardiology; Hippokrateion Hospital; Aristotle University Medical School; Thessaloniki Greece
| | - KONSTANTINOS C. KOSKINAS
- Third Department of Cardiology; Hippokrateion Hospital; Aristotle University Medical School; Thessaloniki Greece
| | - VASSILIOS VASSILIKOS
- Third Department of Cardiology; Hippokrateion Hospital; Aristotle University Medical School; Thessaloniki Greece
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Obel O, Joglar JA. Unveiling the remodeled atrium: lessons from the early recurrence of atrial fibrillation. J Cardiovasc Electrophysiol 2013; 25:168-70. [PMID: 24237906 DOI: 10.1111/jce.12323] [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: 10/23/2013] [Accepted: 10/25/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Owen Obel
- Division of Cardiology, Department of Internal Medicine, the University of Texas Southwestern Medical Center, Dallas, Texas, USA
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30
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Corradi D, Callegari S, Gelsomino S, Lorusso R, Macchi E. Morphology and pathophysiology of target anatomical sites for ablation procedures in patients with atrial fibrillation. Part I: Atrial structures (atrial myocardium and coronary sinus). Int J Cardiol 2013; 168:1758-68. [DOI: 10.1016/j.ijcard.2013.05.091] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 04/22/2013] [Accepted: 05/04/2013] [Indexed: 12/21/2022]
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XU GUOJUN, GAN TIANYI, TANG BAOPENG, CHEN ZUHENG, MAHEMUTI AILIMAN, JIANG TAO, SONG JIANGUO, GUO XIA, LI YAODONG, ZHOU XIANHUI, ZHANG YU, LI JINXIN. Alterations in the expression of atrial calpains in electrical and structural remodeling during aging and atrial fibrillation. Mol Med Rep 2013; 8:1343-52. [DOI: 10.3892/mmr.2013.1684] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 08/16/2013] [Indexed: 11/06/2022] Open
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Kapur S, Macrae CA. The developmental basis of adult arrhythmia: atrial fibrillation as a paradigm. Front Physiol 2013; 4:221. [PMID: 24062689 PMCID: PMC3771314 DOI: 10.3389/fphys.2013.00221] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 08/02/2013] [Indexed: 11/17/2022] Open
Abstract
Normal cardiac rhythm is one of the most fundamental physiologic phenomena, emerging early in the establishment of the vertebrate body plan. The developmental pathways underlying the patterning and maintenance of stable cardiac electrophysiology must be extremely robust, but are only now beginning to be unraveled. The step-wise emergence of automaticity, AV delay and sequential conduction are each tightly regulated and perturbations of these patterning events is now known to play an integral role in pediatric and adult cardiac arrhythmias. Electrophysiologic patterning within individual cardiac chambers is subject to exquisite control and is influenced by early physiology superimposed on the underlying gene networks that regulate cardiogenesis. As additional cell populations migrate to the developing heart these too bring further complexity to the organ, as it adapts to the dynamic requirements of a growing organism. A comprehensive understanding of the developmental basis of normal rhythm will inform not only the mechanisms of inherited arrhythmias, but also the differential regional propensities of the adult heart to acquired arrhythmias. In this review we use atrial fibrillation as a generalizable example where the various factors are perhaps best understood.
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Affiliation(s)
- Sunil Kapur
- Medicine, Cardiovascular Division, Brigham and Women's Hospital and Harvard Medical School Boston, MA, USA
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Constanciel E, N'Djin WA, Bessière F, Chavrier F, Grinberg D, Vignot A, Chevalier P, Chapelon JY, Lafon C. Design and evaluation of a transesophageal HIFU probe for ultrasound-guided cardiac ablation: simulation of a HIFU mini-maze procedure and preliminary ex vivo trials. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2013; 60:1868-83. [PMID: 24658718 DOI: 10.1109/tuffc.2013.2772] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Atrial fibrillation (AF) is the most frequent cardiac arrhythmia. Left atrial catheter ablation is currently performed to treat this disease. Several energy sources are used, such as radio-frequency or cryotherapy. The main target of this procedure is to isolate the pulmonary veins. However, significant complications caused by the invasive procedure are described, such as stroke, tamponade, and atrioesophageal fistula, and a second intervention is often needed to avoid atrial fibrillation recurrence. For these reasons, a minimally-invasive device allowing performance of more complex treatments is still needed. High-intensity focused ultrasound (HIFU) can cause deep tissue lesions without damaging intervening tissues. Left atrial ultrasound-guided transesophageal HIFU ablation could have the potential to become a new ablation technique. The goal of this study was to design and test a minimally-invasive ultrasound-guided transesophageal HIFU probe under realistic treatment conditions. First, numerical simulations were conducted to determine the probe geometry, and to validate the feasibility of performing an AF treatment using a HIFU mini-maze (HIFUMM) procedure. Then, a prototype was manufactured and characterized. The 18-mm-diameter probe head housing contained a 3-MHz spherical truncated HIFU transducer divided into 8 rings, with a 5-MHz commercial transesophageal echocardiography (TEE) transducer integrated in the center. Finally, ex vivo experiments were performed to test the impact of the esophagus layer between the probe and the tissue to treat, and also the influence of the lungs and the vascularization on lesion formation. First results show that this prototype successfully created ex vivo transmural myocardial lesions under ultrasound guidance, while preserving intervening tissues (such as the esophagus). Ultrasound-guided transesophageal HIFU can be a good candidate for treatment of AF in the future.
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Xu GJ, Gan TY, Tang BP, Chen ZH, Mahemuti A, Jiang T, Song JG, Guo X, Li YD, Miao HJ, Zhou XH, Zhang Y, Li JX. Accelerated fibrosis and apoptosis with ageing and in atrial fibrillation: Adaptive responses with maladaptive consequences. Exp Ther Med 2013; 5:723-729. [PMID: 23403858 PMCID: PMC3570166 DOI: 10.3892/etm.2013.899] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 12/14/2012] [Indexed: 12/16/2022] Open
Abstract
The aim of this study was to investigate whether abnormal expression of matrix metalloproteinase (MMP)-9/tissue inhibitors of MMPs (TIMP)-1 and B cell lymphoma 2 (BCL-2)/BCL-2-associated X protein (BAX) are correlated with the characteristic accelerated fibrosis and apoptosis during ageing and in atrial fibrillation (AF). Four groups of dogs were studied: adult dogs in sinus rhythm (SR), aged dogs in SR, adult dogs with AF induced by rapid atrial pacing and aged dogs with AF induced by rapid atrial pacing. The mRNA and protein expression levels of the target gene in the left atrium were measured by quantitative reverse transcription-polymerase chain reaction (RT-PCR) and western blot analysis. Pathohistological and ultrastructural changes were assessed by light and electron microscopy. The apoptotic indices of myocytes were detected by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP) nick end labeling (TUNEL). The mRNA and protein expression levels of MMP-9 and BAX and those of TIMP-1 and BCL-2 were significantly upregulated and down-regulated, respectively, in the aged groups compared with the adult groups. Compared with the control groups, the adult and aged groups with AF exhibited significantly increased mRNA and protein expression levels of MMP-9 and BAX and decreased expression levels of TIMP-1 and BCL-2. Samples of atrial tissue demonstrated abnormal pathohistological and ultrastructural changes, accelerated fibrosis and apoptosis. MMP-9/TIMP-1 and BCL-2/BAX hold potential for use as substrates conducive to AF and their abnormal expression plays a major role in structural remodeling of the atrium.
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Affiliation(s)
- Guo-Jun Xu
- Department of Cardiology, First Affiliated Hospital, Xinjiang Medical University, Urumqi, Xinjiang 830011
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Stirbys P. Interdependent Relationship Between Atrial Fibrillation and Sinus Rhythm at the Hypothetical Interface of Atrial Fibrillation, Autonomic Tone, Sinoatrial Node and Inflammation : Analytical Review, Reconsiderations, Speculations and New Insights. J Atr Fibrillation 2012; 5:613. [PMID: 28496790 PMCID: PMC5153154 DOI: 10.4022/jafib.613] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Revised: 11/15/2012] [Accepted: 11/16/2012] [Indexed: 06/06/2023]
Abstract
Underlying mechanisms of atrial fibrillation occurrence and its self-extinguishing remain not completely investigated yet. The role of autonomic tone and sinoatrial node in the interplay between atrial fibrillation and sinus rhythm is also not fully understood. The influence of inflammation as a possible source of arrhythmia and likelihood of its pharmacologic treatment deserves special attention. These complex issues are important for better understanding of arrhythmogenesis and rhythm control. Conceptual reconsiderations through the new insights primarily on the hypothetic basis may delineate new therapeutic and preventive strategies. The aim of this analytical review was to reinforce the clinical and laboratory studies regarding the role of: 1) autonomic tone and sinoatrial node in restitution of sinus rhythm, 2) new concept of ?vibrantly quiescent stroboscopic tuning? as a matured status of atrial fibrillation being prepared for its abruption by slight impulse, 3) inflammation in the interplay between atrial fibrillation and sinus rhythm, 4) anti-inflammation and anti-allergic therapy to prevent and to treat the arrhythmia.
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Affiliation(s)
- Petras Stirbys
- Department of Cardiology, Hospital of Lithuanian University of Health Sciences , Kaunas Clinics, Kaunas, Lithuania
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Jacquemet V, Kappenberger L, Henriquez CS. Modeling atrial arrhythmias: impact on clinical diagnosis and therapies. IEEE Rev Biomed Eng 2012; 1:94-114. [PMID: 22274901 DOI: 10.1109/rbme.2008.2008242] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Atrial arrhythmias are the most frequent sustained rhythm disorders in humans and often lead to severe complications such as heart failure and stroke. Despite the important insights provided by animal models into the mechanisms of atrial arrhythmias, direct translation of experimental findings to new therapies in patients has not been straightforward. With the advances in computer technology, large-scale electroanatomical computer models of the atria that integrate information from the molecular to organ scale have reached a level of sophistication that they can be used to interpret the outcome of experimental and clinical studies and aid in the rational design of therapies. This paper reviews the state-of-the-art of computer models of the electrical dynamics of the atria and discusses the evolving role of simulation in assisting the clinical diagnosis and treatment of atrial arrhythmias.
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Affiliation(s)
- Vincent Jacquemet
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA.
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Xie LH, Shanmugam M, Park JY, Zhao Z, Wen H, Tian B, Periasamy M, Babu GJ. Ablation of sarcolipin results in atrial remodeling. Am J Physiol Cell Physiol 2012; 302:C1762-71. [PMID: 22496245 DOI: 10.1152/ajpcell.00425.2011] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Sarcolipin (SLN) is a key regulator of sarco(endo)plasmic reticulum (SR) Ca(2+)-ATPase (SERCA), and its expression is altered in diseased atrial myocardium. To determine the precise role of SLN in atrial Ca(2+) homeostasis, we developed a SLN knockout (sln-/-) mouse model and demonstrated that ablation of SLN enhances atrial SERCA pump activity. The present study is designed to determine the long-term effects of enhanced SERCA activity on atrial remodeling in the sln-/- mice. Calcium transient measurements show an increase in atrial SR Ca(2+) load and twitch Ca(2+) transients. Patch-clamping experiments demonstrate activation of the forward mode of sodium/calcium exchanger, increased L-type Ca(2+) channel activity, and prolongation of action potential duration at 90% repolarization in the atrial myocytes of sln-/- mice. Spontaneous Ca(2+) waves, delayed afterdepolarization, and triggered activities are frequent in the atrial myocytes of sln-/- mice. Furthermore, loss of SLN in atria is associated with increased interstitial fibrosis and altered expression of genes encoding collagen and other extracellular matrix proteins. Our results also show that the sln-/- mice are susceptible to atrial arrhythmias upon aging. Together, these findings indicate that ablation of SLN results in increased SERCA activity and SR Ca(2+) load, which, in turn, could cause abnormal intracellular Ca(2+) handling and atrial remodeling.
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Affiliation(s)
- Lai-Hua Xie
- Department of Cell Biology and Molecular Medicine, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, 07103, USA
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Murdock DK, Kaliebe J, Larrain G. The use of ranolazine to facilitate electrical cardioversion in cardioversion-resistant patients: a case series. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2012; 35:302-7. [PMID: 22229482 DOI: 10.1111/j.1540-8159.2011.03298.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Occasionally atrial fibrillation (AF) is resistant to electrical cardioversion (EC). Ranolazine (RZ) is an antianginal agent, which inhibits abnormal late Na(+) channel currents in cardiomyocytes and decreases Na(+) /Ca(++) overload. RZ is a potent inhibitor of after-depolarizations and triggered activity and prolongs atrial refractory periods. We postulated RZ could facilitate EC in patients resistant to EC. METHODS Over a 3-year period, we identified 25 EC-resistant patients who had been administered oral RZ shortly after failing attempted EC. The anterior-posterior cardioversion approach was used and each patient had failed to be restored to sinus rhythm despite using up to the maximum output of a biphasic cardioversion device. Repeat EC was performed 3.5-4 hours after administration of 2 g of oral RZ using the same device, sedation, and lead placement. RESULTS Sinus rhythm was successfully restored in 19 (76%) of 25 EC-resistant patients. Three patients spontaneously converted before the second attempt at EC within 4 hours of the RZ dose. Of the 22 patients undergoing another attempt at EC, 16 were successfully converted to sinus rhythm. Five of the six patients who were refractory to repeat EC despite RZ had AF of unknown duration and each is now in permanent AF. No adverse effects were noted. CONCLUSION RZ shows promise as a safe and convenient agent to facilitate EC in EC-resistant patients. It appears to be most effective in patients whose AF duration is known to be less than 3 months.
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Affiliation(s)
- David K Murdock
- Aspirus Heart and Vascular Institute, Aspirus Cardiovascular Associates, Wausau, WI, USA.
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39
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Nonpharmacologic management of atrial fibrillation: role of the pulmonary veins and posterior left atrium. Heart Rhythm 2011; 6:S5-S11. [PMID: 19959144 DOI: 10.1016/j.hrthm.2009.07.030] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Indexed: 11/21/2022]
Abstract
Nonpharmacologic approaches for the management of atrial fibrillation are rapidly emerging as the mainstay for definitive management of this arrhythmia. Over the past several years, numerous studies reported in the literature have highlighted various aspects of the pathophysiologic mechanisms underlying atrial fibrillation. The purpose of this review is to place the current approaches being used for arrhythmia management in the context of the current knowledge of about arrhythmia mechanisms.
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Bissinger A, Grycewicz T, Grabowicz W, Lubinski A. The effect of diabetic autonomic neuropathy on P-wave duration, dispersion and atrial fibrillation. Arch Med Sci 2011; 7:806-12. [PMID: 22291825 PMCID: PMC3258812 DOI: 10.5114/aoms.2011.25555] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Revised: 11/05/2010] [Accepted: 12/13/2010] [Indexed: 01/19/2023] Open
Abstract
INTRODUCTION Atrial fibrillation (AF) is the most common sustained arrhythmia. Diabetic autonomic neuropathy (DAN) is a frequent complication of diabetes mellitus and has a negative impact on the cardiovascular system. There are no data about the occurrence of paroxysmal atrial fibrillation (PAF) in the population with DAN. MATERIAL AND METHODS We analysed the data of 100 patients with PAF. The study population was divided into three groups: group I: 28 patients with diabetes mellitus (DM) and DAN, group II: 34 patients with DM without DAN, and group III: 38 patients without DM. P-wave duration (FPD) and dispersion (PWD) were measured during sinus rhythm and AF episodes were counted during 12 months of follow-up. RESULTS Recurrence of PAF was higher in group I (47 episodes/year) compared to groups II and III (26 and 22 episodes/year) - p<0.01. The FPD was longer in group I (137.4 ±12.0 ms vs. 126 ±23.0 ms in II group and 129 ±18.3 ms in group III; p<0.001). The PWD was longer in patients with DAN (53 ±19 ms vs. 36 ±18 ms and 34 ± 20 ms, p<0.001). CONCLUSIONS The results showed that the presence of DAN caused a significant increase in P-wave duration and dispersion, which might be responsible for the recurrence of AF.
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Affiliation(s)
- Andrzej Bissinger
- Corresponding author: Andrzej Bissinger MD, PhD, Department of Invasive Cardiology and Cardiodiabetology, Medical University, 113 Zeromskiego, 90-549 Lodz, Poland, Fax: +48426393563, Phone: +48426393563. E-mail:
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Schotten U, Verheule S, Kirchhof P, Goette A. Pathophysiological mechanisms of atrial fibrillation: a translational appraisal. Physiol Rev 2011; 91:265-325. [PMID: 21248168 DOI: 10.1152/physrev.00031.2009] [Citation(s) in RCA: 860] [Impact Index Per Article: 66.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Atrial fibrillation (AF) is an arrhythmia that can occur as the result of numerous different pathophysiological processes in the atria. Some aspects of the morphological and electrophysiological alterations promoting AF have been studied extensively in animal models. Atrial tachycardia or AF itself shortens atrial refractoriness and causes loss of atrial contractility. Aging, neurohumoral activation, and chronic atrial stretch due to structural heart disease activate a variety of signaling pathways leading to histological changes in the atria including myocyte hypertrophy, fibroblast proliferation, and complex alterations of the extracellular matrix including tissue fibrosis. These changes in electrical, contractile, and structural properties of the atria have been called "atrial remodeling." The resulting electrophysiological substrate is characterized by shortening of atrial refractoriness and reentrant wavelength or by local conduction heterogeneities caused by disruption of electrical interconnections between muscle bundles. Under these conditions, ectopic activity originating from the pulmonary veins or other sites is more likely to occur and to trigger longer episodes of AF. Many of these alterations also occur in patients with or at risk for AF, although the direct demonstration of these mechanisms is sometimes challenging. The diversity of etiological factors and electrophysiological mechanisms promoting AF in humans hampers the development of more effective therapy of AF. This review aims to give a translational overview on the biological basis of atrial remodeling and the proarrhythmic mechanisms involved in the fibrillation process. We pay attention to translation of pathophysiological insights gained from in vitro experiments and animal models to patients. Also, suggestions for future research objectives and therapeutical implications are discussed.
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Affiliation(s)
- Ulrich Schotten
- Department of Physiology, University Maastricht, Maastricht, The Netherlands.
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Workman AJ, Smith GL, Rankin AC. Mechanisms of termination and prevention of atrial fibrillation by drug therapy. Pharmacol Ther 2011; 131:221-41. [PMID: 21334377 DOI: 10.1016/j.pharmthera.2011.02.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Accepted: 02/09/2011] [Indexed: 01/13/2023]
Abstract
Atrial fibrillation (AF) is a disorder of the rhythm of electrical activation of the cardiac atria. It is the most common cardiac arrhythmia, has multiple aetiologies, and increases the risk of death from stroke. Pharmacological therapy is the mainstay of treatment for AF, but currently available anti-arrhythmic drugs have limited efficacy and safety. An improved understanding of how anti-arrhythmic drugs affect the electrophysiological mechanisms of AF initiation and maintenance, in the setting of the different cardiac diseases that predispose to AF, is therefore required. A variety of animal models of AF has been developed, to represent and control the pathophysiological causes and risk factors of AF, and to permit the measurement of detailed and invasive parameters relating to the associated electrophysiological mechanisms of AF. The purpose of this review is to examine, consolidate and compare available relevant data on in-vivo electrophysiological mechanisms of AF suppression by currently approved and investigational anti-arrhythmic drugs in such models. These include the Vaughan Williams class I-IV drugs, namely Na(+) channel blockers, β-adrenoceptor antagonists, action potential prolonging drugs, and Ca(2+) channel blockers; the "upstream therapies", e.g., angiotensin converting enzyme inhibitors, statins and fish oils; and a variety of investigational drugs such as "atrial-selective" multiple ion channel blockers, gap junction-enhancers, and intracellular Ca(2+)-handling modulators. It is hoped that this will help to clarify the main electrophysiological mechanisms of action of different and related drug types in different disease settings, and the likely clinical significance and potential future exploitation of such mechanisms.
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Affiliation(s)
- A J Workman
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, 126 University Place, Glasgow G12 8TA, United Kingdom.
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Eagle KA, Cannom DS, Garcia DA. Management of atrial fibrillation: translating clinical trial data into clinical practice. Am J Med 2011; 124:4-14. [PMID: 20932504 DOI: 10.1016/j.amjmed.2010.05.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Revised: 05/17/2010] [Accepted: 05/20/2010] [Indexed: 11/25/2022]
Abstract
Atrial fibrillation is a supraventricular tachyarrhythmia with significant consequences in terms of morbidity and mortality. In light of the limitations of available pharmacologic treatment options (suboptimal efficacy plus safety and tolerability issues), atrial fibrillation management should be individualized based on patient characteristics and comorbidities that could influence response to specific management approaches. The importance of adequate anticoagulation should not be overlooked. This review provides a practical guide for primary care physicians, internists, and cardiologists on current management strategies for atrial fibrillation, based on recent guidelines and current clinical data.
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Affiliation(s)
- Kim A Eagle
- Albion Walter Hewlett, University of Michigan Health System, Ann Arbor, MI 48109-5852, USA.
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Abstract
Atrial fibrillation (AF) is the most commonly encountered clinical arrhythmia associated with pronounced morbidity, mortality, and socio-economic burden. This pathological entity is associated with an altered expression profile of genes that are important for atrial function. MicroRNAs (miRNAs), a new class of non-coding mRNAs of around 22 nucleotides in length, have rapidly emerged as one of the key players in the gene expression regulatory network. The potential roles of miRNAs in controlling AF have recently been investigated. The studies have provided some promising results for our better understanding of the molecular mechanisms of AF. In this review article, we provide a synopsis of the studies linking miRNAs to cardiac excitability and other processes pertinent to AF. To introduce the main topic, we discuss basic knowledge about miRNA biology and our current understanding of mechanisms for AF. The most up-to-date research data on the possible roles of miRNAs in AF initiation and maintenance are presented, and the available experimental results on miRNA and AF are discussed. Some speculations pertinent to the subject are made. Finally, perspectives on future directions of research on miRNAs in AF are provided.
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Affiliation(s)
- Zhiguo Wang
- Research Center, Montreal Heart Institute, 5000 Belanger East, Montreal, Canada PQ H1T 1C8.
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CORRADI DOMENICO, MAESTRI ROBERTA, MACCHI EMILIO, CALLEGARI SERGIO. Clinical Reviews: The Atria: From Morphology to Function. J Cardiovasc Electrophysiol 2010; 22:223-35. [DOI: 10.1111/j.1540-8167.2010.01887.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Gard JJ, Asirvatham SJ. Ranolazine for Atrial Fibrillation: Too Good to be True? J Atr Fibrillation 2010; 3:297. [PMID: 28496664 PMCID: PMC4956353 DOI: 10.4022/jafib.297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Revised: 08/19/2010] [Accepted: 08/19/2010] [Indexed: 06/07/2023]
Affiliation(s)
- Joseph J Gard
- Department of Internal Medicine, Mayo Clinic, Rochester, MN, USA
| | - Samuel J Asirvatham
- Department of Internal Medicine, Mayo Clinic, Rochester, MN, USA
- Division of Pediatric Cardiology, Department of Pediatrics and Adolescent Medicine, Mayo Clinic, Rochester, MN, USA
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Murdock DK, Reiffel J, Kaliebe J, Larrain G. Electrophysiological Changes of the Atrium in Patients with Lone Paroxysmal Atrial Fibrillation. J Atr Fibrillation 2010; 3:251. [PMID: 28496660 PMCID: PMC4956349 DOI: 10.4022/jafib.251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Revised: 07/19/2010] [Accepted: 08/14/2010] [Indexed: 06/07/2023]
Abstract
BACKGROUND The "Pill-in-Pocket" (PIP) is an approach to atrial fibrillation (AF) where oral anti-arrhythmics at 75% to 100% of the normal daily dose, given as a single dose, is used to convert recent-onset AF. Pro-arrhythmic risk has limited this approach to patients without structural heart disease (SHD). Ranolazine is an anti-anginal agent, which inhibits the abnormal late Na+ channel current resulting in decreased Na+/Ca++ overload. This inhibits after-depolarizations and reduces pulmonary vein firing, which have been implicated in the initiation and propagation of AF. Ranolazine increases atrial refractoriness and has no known pro-arrhythmic affects. Ranolazine is routinely given to patients with SHD. The ability of Ranolazine to terminate AF in man has not been described but if useful could be a safer PIP agent with application in the presence or absence of SHD. We describe our experience using oral Ranolazine to convert new or recurrent AF. METHOD 2000 mg of ranolazine was administered to 35 patients with new (16 patients) or recurrent (19 patients) AF of at least 3 but not greater than 48 hours duration. Clinical features, echocardiographic data, and SHD were noted. Success was defined as restoring sinus rhythm within 6 hours of Ranolazine. RESULTS All but 4 patients had some form of SHD. Twenty-five patients were in the hospital, 5 were in the office, and 5 were at home at the time Ranolazine was administered. Twenty-five of 35 patients converted to sinus rhythm. No pro-arrhythmic effects, hemodynamic instability, adverse rate effects, or perceived intolerance were noted. The 71% conversion rate was comparable to other reported PIP protocols and much higher than reported placebo conversion rates. CONCLUSIONS High dose oral Ranolazine shows utility as a possible safe agent to convert new or recurrent AF. Larger placebo-controlled studies would appear to be warranted.
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Affiliation(s)
- David K Murdock
- Cardiovascular Associates of Northern Wisconsin
- CARE Foundation, Inc
- Aspirus Wausau Hospital
| | | | | | - German Larrain
- Cardiovascular Associates of Northern Wisconsin
- CARE Foundation, Inc
- Aspirus Wausau Hospital
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Workman AJ. Cardiac adrenergic control and atrial fibrillation. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2010; 381:235-49. [PMID: 19960186 PMCID: PMC2855383 DOI: 10.1007/s00210-009-0474-0] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Accepted: 11/08/2009] [Indexed: 10/20/2022]
Abstract
Atrial fibrillation (AF) is the most common cardiac arrhythmia, and it causes substantial mortality. The autonomic nervous system, and particularly the adrenergic/cholinergic balance, has a profound influence on the occurrence of AF. Adrenergic stimulation from catecholamines can cause AF in patients. In human atrium, catecholamines can affect each of the electrophysiological mechanisms of AF initiation and/or maintenance. Catecholamines may produce membrane potential oscillations characteristic of afterdepolarisations, by increasing Ca(2+) current, [Ca(2+)](i) and consequent Na(+)-Ca(2+) exchange, and may also enhance automaticity. Catecholamines might affect reentry, by altering excitability or conduction, rather than action potential terminal repolarisation or refractory period. However, which arrhythmia mechanisms predominate is unclear, and likely depends on cardiac pathology and adrenergic tone. Heart failure (HF), a major cause of AF, causes adrenergic activation and adaptational changes, remodelling, of atrial electrophysiology, Ca(2+) homeostasis, and adrenergic responses. Chronic AF also remodels these, but differently to HF. Myocardial infarction and AF cause neural remodelling that also may promote AF. beta-Adrenoceptor antagonists (beta-blockers) are used in the treatment of AF, mainly to control the ventricular rate, by slowing atrioventricular conduction. beta-Blockers also reduce the incidence of AF, particularly in HF or after cardiac surgery, when adrenergic tone is high. Furthermore, the chronic treatment of patients with beta-blockers remodels the atria, with a potentially antiarrhythmic increase in the refractory period. Therefore, the suppression of AF by beta-blocker treatment may involve an attenuation of arrhythmic activity that is caused by increased [Ca(2+)](i), coupled with effects of adaptation to the treatment. An improved understanding of the involvement of the adrenergic system and its control in basic mechanisms of AF under differing cardiac pathologies might lead to better treatments.
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Affiliation(s)
- Antony J Workman
- British Heart Foundation Glasgow Cardiovascular Research Centre, Division of Cardiovascular and Medical Sciences, Faculty of Medicine, University of Glasgow, 126 University Place, Glasgow, G12 8TA, UK.
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Guo D, Young L, Wu Y, Belardinelli L, Kowey PR, Yan GX. Increased late sodium current in left atrial myocytes of rabbits with left ventricular hypertrophy: its role in the genesis of atrial arrhythmias. Am J Physiol Heart Circ Physiol 2010; 298:H1375-81. [PMID: 20190097 DOI: 10.1152/ajpheart.01145.2009] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Left ventricular hypertrophy (LVH) is frequently associated with clinical atrial arrhythmias, but little is known about how it causes those arrhythmias. Our previous studies have shown that LVH increases the late sodium current (I(Na-L)) that plays an important role in the genesis of ventricular arrhythmias. We hypothesize that LVH may also induce an upregulation of the I(Na-L) in atrial myocytes, leading to atrial electrical abnormalities. The renovascular hypertension model was used to induce LVH in rabbits. Action potential and membrane current recordings were performed in single myocytes. At a pacing cycle length of 2,000 ms, spontaneous phase-2 early afterdepolarizations (EADs) could be recorded from the left atrial myocytes in 10 of 12 LVH rabbits, whereas no EADs could be elicited in right atrial myocytes of LVH rabbits or atrial myocytes from any of the 12 control rabbits. Spontaneous automaticity (SA) from left atrial myocytes was observed in 9 out of 12 LVH rabbits, but none in right atrial myocytes of LVH rabbits or control rabbits, at a pacing rate of 8,000 ms. The left atrial myocytes of LVH rabbits had a significantly higher density of the I(Na-L) compared with those of control rabbits (0.90 +/- 0.12 in LVH vs. 0.50 +/- 0.08 pA/pF in control, n = 8, P < 0.01). Tetrodotoxin, an I(Na-L) blocker, abolished all atrial EADs and SA at 10 microM. Our results demonstrate that LVH induction results in a significant increase of I(Na-L) in the left atrial myocytes that may render these cells susceptible to the genesis of EADs and SA. The I(Na-L) may serve as a potentially useful ionic target for antiarrhythmic drugs for the treatment of atrial arrhythmias in the setting of LVH.
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Affiliation(s)
- Donglin Guo
- Main Line Health Heart Center & Lankenau Inst., Medical Research, 100 Lancaster Ave., Wynnewood, PA 19096, USA.
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[Pathophysiopathology of atrial fibrillation: applications to treatment]. Ann Cardiol Angeiol (Paris) 2010; 58 Suppl 1:S6-10. [PMID: 20103185 DOI: 10.1016/s0003-3928(09)73389-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The origin and persistence of AF result from a complex interaction between triggers, autonomic nervous system, substrate, and factors involved in atrial remodelling. The pathophysiology of AF differs from one patient to another, but recent advances have helped us to understand more about involved mechanisms and to translate this knowledge into improvements in AF therapy. An illustration is the elimination of triggers within pulmonary veins by means of catheter ablation. Dealing with structural atrial remodelling and atrial fibrosis remains still a great challenge. Solving these problems could help us to develop new approaches to AF prevention and treatment.
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