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Fossier L, Ben-Johny M. New insights on cardiac Na channel block by an atypical anti-arrhythmic drug. NATURE CARDIOVASCULAR RESEARCH 2023; 2:494-495. [PMID: 39195887 DOI: 10.1038/s44161-023-00284-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/29/2024]
Affiliation(s)
- Lucile Fossier
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Manu Ben-Johny
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA.
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2
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Casini S, Marchal GA, Kawasaki M, Fabrizi B, Wesselink R, Nariswari FA, Neefs J, van den Berg NWE, Driessen AHG, de Groot JR, Verkerk AO, Remme CA. Differential Sodium Current Remodelling Identifies Distinct Cellular Proarrhythmic Mechanisms in Paroxysmal vs Persistent Atrial Fibrillation. Can J Cardiol 2023; 39:277-288. [PMID: 36586483 DOI: 10.1016/j.cjca.2022.12.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 12/24/2022] [Accepted: 12/26/2022] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND The cellular mechanisms underlying progression from paroxysmal to persistent atrial fibrillation (AF) are not fully understood, but alterations in (late) sodium current (INa) have been proposed. Human studies investigating electrophysiological changes at the paroxysmal stage of AF are sparse, with the majority employing right atrial appendage cardiomyocytes (CMs). We here investigated action potential (AP) characteristics and (late) INa remodelling in left atrial appendage CMs (LAA-CMs) from patients with paroxysmal and persistent AF and patients in sinus rhythm (SR), as well as the potential contribution of the "neuronal" sodium channel SCN10A/NaV1.8. METHODS Peak INa, late INa and AP properties were investigated through patch-clamp analysis on single LAA-CMs, whereas quantitative polymerase chain reaction was used to assess SCN5A/SCN10A expression levels in LAA tissue. RESULTS In paroxysmal and persistent AF LAA-CMs, AP duration was shorter than in SR LAA-CMs. Compared with SR, peak INa and SCN5A expression were significantly decreased in paroxysmal AF, whereas they were restored to SR levels in persistent AF. Conversely, although late INa was unchanged in paroxysmal AF compared with SR, it was significantly increased in persistent AF. Peak or late Nav1.8-based INa was not detected in persistent AF LAA-CMs. Similarly, expression of SCN10A was not observed in LAAs at any stage. CONCLUSIONS Our findings demonstrate differences in (late) INa remodeling in LAA-CMs from patients with paroxysmal vs persistent AF, indicating distinct cellular proarrhythmic mechanisms in different AF forms. These observations are of particular relevance when considering potential pharmacologic approaches targeting (late) INa in AF.
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Affiliation(s)
- Simona Casini
- Amsterdam UMC, location University of Amsterdam, Department of Experimental Cardiology, Amsterdam Cardiovascular Sciences, Heart failure & Arrhythmias, Amsterdam, The Netherlands.
| | - Gerard A Marchal
- Amsterdam UMC, location University of Amsterdam, Department of Experimental Cardiology, Amsterdam Cardiovascular Sciences, Heart failure & Arrhythmias, Amsterdam, The Netherlands
| | - Makiri Kawasaki
- Amsterdam UMC, location University of Amsterdam, Department of Experimental Cardiology, Amsterdam Cardiovascular Sciences, Heart failure & Arrhythmias, Amsterdam, The Netherlands
| | - Benedetta Fabrizi
- Amsterdam UMC, location University of Amsterdam, Department of Experimental Cardiology, Amsterdam Cardiovascular Sciences, Heart failure & Arrhythmias, Amsterdam, The Netherlands
| | - Robin Wesselink
- Amsterdam UMC, location University of Amsterdam, Department of Cardiology, Amsterdam Cardiovascular Sciences, Heart failure & Arrhythmias, Amsterdam, The Netherlands
| | - Fransisca A Nariswari
- Amsterdam UMC, location University of Amsterdam, Department of Experimental Cardiology, Amsterdam Cardiovascular Sciences, Heart failure & Arrhythmias, Amsterdam, The Netherlands
| | - Jolien Neefs
- Amsterdam UMC, location University of Amsterdam, Department of Cardiology, Amsterdam Cardiovascular Sciences, Heart failure & Arrhythmias, Amsterdam, The Netherlands
| | - Nicoline W E van den Berg
- Amsterdam UMC, location University of Amsterdam, Department of Cardiology, Amsterdam Cardiovascular Sciences, Heart failure & Arrhythmias, Amsterdam, The Netherlands
| | - Antoine H G Driessen
- Amsterdam UMC, location University of Amsterdam, Department of Cardiology, Amsterdam Cardiovascular Sciences, Heart failure & Arrhythmias, Amsterdam, The Netherlands
| | - Joris R de Groot
- Amsterdam UMC, location University of Amsterdam, Department of Cardiology, Amsterdam Cardiovascular Sciences, Heart failure & Arrhythmias, Amsterdam, The Netherlands
| | - Arie O Verkerk
- Amsterdam UMC, location University of Amsterdam, Department of Experimental Cardiology, Amsterdam Cardiovascular Sciences, Heart failure & Arrhythmias, Amsterdam, The Netherlands; Amsterdam UMC, location University of Amsterdam, Department of Medical Biology, Amsterdam Cardiovascular Sciences, Heart failure & Arrhythmias, Amsterdam, The Netherlands
| | - Carol Ann Remme
- Amsterdam UMC, location University of Amsterdam, Department of Experimental Cardiology, Amsterdam Cardiovascular Sciences, Heart failure & Arrhythmias, Amsterdam, The Netherlands.
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3
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Angelini M, Pezhouman A, Savalli N, Chang MG, Steccanella F, Scranton K, Calmettes G, Ottolia M, Pantazis A, Karagueuzian HS, Weiss JN, Olcese R. Suppression of ventricular arrhythmias by targeting late L-type Ca2+ current. J Gen Physiol 2021; 153:212725. [PMID: 34698805 PMCID: PMC8552156 DOI: 10.1085/jgp.202012584] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 07/15/2021] [Accepted: 09/02/2021] [Indexed: 12/15/2022] Open
Abstract
Ventricular arrhythmias, a leading cause of sudden cardiac death, can be triggered by cardiomyocyte early afterdepolarizations (EADs). EADs can result from an abnormal late activation of L-type Ca2+ channels (LTCCs). Current LTCC blockers (class IV antiarrhythmics), while effective at suppressing EADs, block both early and late components of ICa,L, compromising inotropy. However, computational studies have recently demonstrated that selective reduction of late ICa,L (Ca2+ influx during late phases of the action potential) is sufficient to potently suppress EADs, suggesting that effective antiarrhythmic action can be achieved without blocking the early peak ICa,L, which is essential for proper excitation–contraction coupling. We tested this new strategy using a purine analogue, roscovitine, which reduces late ICa,L with minimal effect on peak current. Scaling our investigation from a human CaV1.2 channel clone to rabbit ventricular myocytes and rat and rabbit perfused hearts, we demonstrate that (1) roscovitine selectively reduces ICa,L noninactivating component in a human CaV1.2 channel clone and in ventricular myocytes native current, (2) the pharmacological reduction of late ICa,L suppresses EADs and EATs (early after Ca2+ transients) induced by oxidative stress and hypokalemia in isolated myocytes, largely preserving cell shortening and normal Ca2+ transient, and (3) late ICa,L reduction prevents/suppresses ventricular tachycardia/fibrillation in ex vivo rabbit and rat hearts subjected to hypokalemia and/or oxidative stress. These results support the value of an antiarrhythmic strategy based on the selective reduction of late ICa,L to suppress EAD-mediated arrhythmias. Antiarrhythmic therapies based on this idea would modify the gating properties of CaV1.2 channels rather than blocking their pore, largely preserving contractility.
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Affiliation(s)
- Marina Angelini
- Division of Molecular Medicine, Department of Anesthesiology & Perioperative Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Arash Pezhouman
- Department of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Nicoletta Savalli
- Division of Molecular Medicine, Department of Anesthesiology & Perioperative Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Marvin G Chang
- Department of Anesthesia and Critical Care, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Federica Steccanella
- Division of Molecular Medicine, Department of Anesthesiology & Perioperative Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Kyle Scranton
- Division of Molecular Medicine, Department of Anesthesiology & Perioperative Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Guillaume Calmettes
- Department of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Michela Ottolia
- Division of Molecular Medicine, Department of Anesthesiology & Perioperative Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA.,University of California, Los Angeles Cardiovascular Theme, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Antonios Pantazis
- Division of Neurobiology, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden.,Wallenberg Center for Molecular Medicine, Linköping University, Linköping, Sweden
| | - Hrayr S Karagueuzian
- Department of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA.,Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - James N Weiss
- Department of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA.,Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA.,Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Riccardo Olcese
- Division of Molecular Medicine, Department of Anesthesiology & Perioperative Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA.,Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA.,University of California, Los Angeles Cardiovascular Theme, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA.,Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
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4
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Verrier RL, Nearing BD, D'Avila A. Spectrum of clinical applications of interlead ECG heterogeneity assessment: From myocardial ischemia detection to sudden cardiac death risk stratification. Ann Noninvasive Electrocardiol 2021; 26:e12894. [PMID: 34592018 PMCID: PMC8588374 DOI: 10.1111/anec.12894] [Citation(s) in RCA: 6] [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: 07/23/2021] [Revised: 08/23/2021] [Accepted: 09/03/2021] [Indexed: 12/11/2022] Open
Abstract
Heterogeneity in depolarization and repolarization among regions of cardiac cells has long been recognized as a major factor in cardiac arrhythmogenesis. This fundamental principle has motivated development of noninvasive techniques for quantification of heterogeneity using the surface electrocardiogram (ECG). The initial approaches focused on interval analysis such as interlead QT dispersion and Tpeak -Tend difference. However, because of inherent difficulties in measuring the termination point of the T wave and commonly encountered irregularities in the apex of the T wave, additional techniques have been pursued. The newer methods incorporate assessment of the entire morphology of the T wave and in some cases of the R wave as well. This goal has been accomplished using a number of promising vectorial approaches with the resting 12-lead ECG. An important limitation of vectorcardiographic analyses is that they require exquisite stability of the recordings and are not inherently suitable for use in exercise tolerance testing (ETT) and/or ambulatory ECG monitoring for provocative stress testing or evaluation of the influence of daily activities on cardiac electrical instability. The objectives of the present review are to describe a technique that has been under clinical evaluation for nearly a decade, termed "interlead ECG heterogeneity." Preclinical testing data will be briefly reviewed. We will discuss the main clinical findings with regard to sudden cardiac death risk stratification, heart failure evaluation, and myocardial ischemia detection using standard recording platforms including resting 12-lead ECG, ambulatory ECG monitoring, ETT, and pharmacologic stress testing in conjunction with single-photon emission computed tomography myocardial perfusion imaging.
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Affiliation(s)
- Richard L Verrier
- Division of Cardiovascular Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Bruce D Nearing
- Division of Cardiovascular Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Andre D'Avila
- Division of Cardiovascular Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
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5
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Late Sodium Current in Atrial Cardiomyocytes Contributes to the Induced and Spontaneous Atrial Fibrillation in Rabbit Hearts. J Cardiovasc Pharmacol 2021; 76:437-444. [PMID: 32675747 DOI: 10.1097/fjc.0000000000000883] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Increased late sodium current (INa) induces long QT syndrome 3 with increased risk of atrial fibrillation (AF). The role of atrial late INa in the induction of AF and in the treatment of AF was determined in this study. AF parameters were measured in isolated rabbit hearts exposed to late INa enhancer and inhibitors. Late INa from isolated atrial and ventricular myocytes were measured using whole-cell patch-clamp techniques. We found that induced-AF by programmed S1S2 stimulation and spontaneous episodes of AF were recorded in hearts exposed to either low (0.1-3 nM) or high (3-10 nM) concentrations of ATX-II (n = 10). Prolongations in atrial monophasic action potential duration at 90% completion of repolarization and effective refractory period by ATX-II (0.1-15 nM) were greater in hearts paced at slow than at fast rates (n = 5-10, P < 0.05). Both endogenous and ATX-II-enhanced late INa density were greater in atrial than that in ventricular myocytes (n = 9 and 8, P < 0.05). Eleclazine and ranolazine reduced AF window and AF burden in association with the inhibition of both endogenous and enhanced atrial late INa with half maximal inhibitory concentrations (IC50) of 1.14 and 9.78, and 0.94 and 8.31 μM, respectively. The IC50s for eleclazine and ranolazine to inhibit peak INa were 20.67 and 101.79 μM, respectively, in atrial myocytes. In conclusion, enhanced late INa in atrial myocytes increases the susceptibility for AF. Inhibition of either endogenous or enhanced late INa, with increased atrial potency of drugs is feasible for the treatment of AF.
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6
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You T, Luo C, Zhang K, Zhang H. Electrophysiological Mechanisms Underlying T-Wave Alternans and Their Role in Arrhythmogenesis. Front Physiol 2021; 12:614946. [PMID: 33746768 PMCID: PMC7969788 DOI: 10.3389/fphys.2021.614946] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 02/10/2021] [Indexed: 12/18/2022] Open
Abstract
T-wave alternans (TWA) reflects every-other-beat alterations in the morphology of the electrocardiogram ST segment or T wave in the setting of a constant heart rate, hence, in the absence of heart rate variability. It is believed to be associated with the dispersion of repolarization and has been used as a non-invasive marker for predicting the risk of malignant cardiac arrhythmias and sudden cardiac death as numerous studies have shown. This review aims to provide up-to-date review on both experimental and simulation studies in elucidating possible mechanisms underlying the genesis of TWA at the cellular level, as well as the genesis of spatially concordant/discordant alternans at the tissue level, and their transition to cardiac arrhythmia. Recent progress and future perspectives in antiarrhythmic therapies associated with TWA are also discussed.
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Affiliation(s)
- Tingting You
- Key Lab of Medical Electrophysiology, Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - Cunjin Luo
- School of Computer Science and Electronic Engineering, University of Essex, Colchester, United Kingdom
| | - Kevin Zhang
- School of Medicine, Imperial College of London, London, United Kingdom
| | - Henggui Zhang
- Key Lab of Medical Electrophysiology, Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China.,Department of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
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7
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Abstract
Pharmacologic management of atrial fibrillation (AF) is a pressing problem. This arrhythmia afflicts >5 million individuals in the United States and prevalence is estimated to rise to 12 million by 2050. Although the pill-in-the-pocket regimen for self-administered AF cardioversion introduced over a decade ago has proven useful, significant drawbacks exist. Among these are the relatively long latency of effects in the range of hours along with potential for hypotension and other adverse effects. This experience prompted development of a new strategy for increasing plasma concentrations of antiarrhythmic drugs rapidly and for a limited time, namely, pulmonary delivery. In preclinical studies in Yorkshire pigs, intratracheal administration of flecainide was shown to cause a rapid, reproducible increase in plasma drug levels. Moreover, pulmonary delivery of flecainide converted AF to normal sinus rhythm by prolonging atrial depolarization, which slows intra-atrial conduction and seems to be directly correlated with efficacy in converting AF. The rapid rise in plasma flecainide levels optimizes its anti-AF effects while minimizing adverse influences on ventricular depolarization and contractility. A more concentrated and soluble formulation of flecainide using a novel cyclodextrin complex excipient reduced net drug delivery for AF conversion when compared to the acetate formulation. Inhalation of the beta-adrenergic blocking agent metoprolol slows ventricular rate and can also terminate AF. In human subjects, oral inhalation of flecainide acetate with a hand-held, breath-actuated nebulizer results in signature prolongation of the QRS complex without serious adverse events. Thus, pulmonary delivery is a promising advance in pharmacologic approach to management of AF.
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8
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Potet F, Egecioglu DE, Burridge PW, George AL. GS-967 and Eleclazine Block Sodium Channels in Human Induced Pluripotent Stem Cell–Derived Cardiomyocytes. Mol Pharmacol 2020; 98:540-547. [DOI: 10.1124/molpharm.120.000048] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 08/24/2020] [Indexed: 11/22/2022] Open
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9
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Caves RE, Carpenter A, Choisy SC, Clennell B, Cheng H, McNiff C, Mann B, Milnes JT, Hancox JC, James AF. Inhibition of voltage-gated Na + currents by eleclazine in rat atrial and ventricular myocytes. Heart Rhythm O2 2020; 1:206-214. [PMID: 32864638 PMCID: PMC7442036 DOI: 10.1016/j.hroo.2020.05.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Background Atrial-ventricular differences in voltage-gated Na+ currents might be exploited for atrial-selective antiarrhythmic drug action for the suppression of atrial fibrillation without risk of ventricular tachyarrhythmia. Eleclazine (GS-6615) is a putative antiarrhythmic drug with properties similar to the prototypical atrial-selective Na+ channel blocker ranolazine that has been shown to be safe and well tolerated in patients. Objective The present study investigated atrial-ventricular differences in the biophysical properties and inhibition by eleclazine of voltage-gated Na+ currents. Methods The fast and late components of whole-cell voltage-gated Na+ currents (respectively, INa and INaL) were recorded at room temperature (∼22°C) from rat isolated atrial and ventricular myocytes. Results Atrial INa activated at command potentials ∼5.5 mV more negative and inactivated at conditioning potentials ∼7 mV more negative than ventricular INa. There was no difference between atrial and ventricular myocytes in the eleclazine inhibition of INaL activated by 3 nM ATX-II (IC50s ∼200 nM). Eleclazine (10 μM) inhibited INa in atrial and ventricular myocytes in a use-dependent manner consistent with preferential activated state block. Eleclazine produced voltage-dependent instantaneous inhibition in atrial and ventricular myocytes; it caused a negative shift in voltage of half-maximal inactivation and slowed the recovery of INa from inactivation in both cell types. Conclusions Differences exist between rat atrial and ventricular myocytes in the biophysical properties of INa. The more negative voltage dependence of INa activation/inactivation in atrial myocytes underlies differences between the 2 cell types in the voltage dependence of instantaneous inhibition by eleclazine. Eleclazine warrants further investigation as an atrial-selective antiarrhythmic drug.
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Affiliation(s)
- Rachel E Caves
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Alexander Carpenter
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Stéphanie C Choisy
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Ben Clennell
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Hongwei Cheng
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Cameron McNiff
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Brendan Mann
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, United Kingdom
| | | | - Jules C Hancox
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Andrew F James
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, United Kingdom
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10
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Abstract
Atrial fibrillation (AF) is the most common sustained arrhythmia encountered in humans and is a significant source of morbidity and mortality. Despite its prevalence, our mechanistic understanding is incomplete, the therapeutic options have limited efficacy, and are often fraught with risks. A better biological understanding of AF is needed to spearhead novel therapeutic avenues. Although "natural" AF is nearly nonexistent in most species, animal models have contributed significantly to our understanding of AF and some therapeutic options. However, the impediments of animal models are also apparent and stem largely from the differences in basic physiology as well as the complexities underlying human AF; these preclude the creation of a "perfect" animal model and have obviated the translation of animal findings. Herein, we review the vast array of AF models available, spanning the mouse heart (weighing 1/1000th of a human heart) to the horse heart (10× heavier than the human heart). We attempt to highlight the features of each model that bring value to our understanding of AF but also the shortcomings and pitfalls. Finally, we borrowed the concept of a SWOT analysis from the business community (which stands for strengths, weaknesses, opportunities, and threats) and applied this introspective type of analysis to animal models for AF. We identify unmet needs and stress that is in the context of rapidly advancing technologies, these present opportunities for the future use of animal models.
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Affiliation(s)
- Dominik Schüttler
- From the Department of Medicine I, University Hospital Munich, Campus Großhadern, Ludwig-Maximilians University Munich (LMU), Germany (D.S., S.K., P.T., S.C.).,DZHK (German Centre for Cardiovascular Research), Partner Site Munich, Munich Heart Alliance (MHA), Germany (D.S., S.K., P.T., S.C.).,Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians University Munich (LMU), Germany (D.S., P.T., S.C.)
| | - Aneesh Bapat
- Cardiovascular Research Center, Massachusetts General Hospital, Harvard Medical School, Boston (A.B., K.L., W.J.H.).,Cardiac Arrhythmia Service, Division of Cardiology, Massachusetts General Hospital, Boston (A.B., W.J.H.)
| | - Stefan Kääb
- From the Department of Medicine I, University Hospital Munich, Campus Großhadern, Ludwig-Maximilians University Munich (LMU), Germany (D.S., S.K., P.T., S.C.).,DZHK (German Centre for Cardiovascular Research), Partner Site Munich, Munich Heart Alliance (MHA), Germany (D.S., S.K., P.T., S.C.)
| | - Kichang Lee
- Cardiovascular Research Center, Massachusetts General Hospital, Harvard Medical School, Boston (A.B., K.L., W.J.H.)
| | - Philipp Tomsits
- From the Department of Medicine I, University Hospital Munich, Campus Großhadern, Ludwig-Maximilians University Munich (LMU), Germany (D.S., S.K., P.T., S.C.).,DZHK (German Centre for Cardiovascular Research), Partner Site Munich, Munich Heart Alliance (MHA), Germany (D.S., S.K., P.T., S.C.).,Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians University Munich (LMU), Germany (D.S., P.T., S.C.)
| | - Sebastian Clauss
- From the Department of Medicine I, University Hospital Munich, Campus Großhadern, Ludwig-Maximilians University Munich (LMU), Germany (D.S., S.K., P.T., S.C.).,DZHK (German Centre for Cardiovascular Research), Partner Site Munich, Munich Heart Alliance (MHA), Germany (D.S., S.K., P.T., S.C.).,Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians University Munich (LMU), Germany (D.S., P.T., S.C.)
| | - William J Hucker
- Cardiovascular Research Center, Massachusetts General Hospital, Harvard Medical School, Boston (A.B., K.L., W.J.H.).,Cardiac Arrhythmia Service, Division of Cardiology, Massachusetts General Hospital, Boston (A.B., W.J.H.)
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11
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Silva AC, de Antonio VZ, Sroubek J, Gervino E, Ho K, Medeiros SA, Silva FT, Pedreira GC, Stocco FG, Nearing BD, Verrier RL. Exercise and pharmacologic stress-induced interlead T-wave heterogeneity analysis to detect clinically significant coronary artery stenosis. Int J Cardiol 2020; 298:32-38. [PMID: 31412992 DOI: 10.1016/j.ijcard.2019.07.066] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 07/08/2019] [Accepted: 07/22/2019] [Indexed: 11/17/2022]
Abstract
BACKGROUND Despite widespread use of ETT and vasodilator-stress with myocardial perfusion imaging (MPI) for noninvasive detection of flow-limiting coronary artery disease, there is continued need to improve diagnostic accuracy. We examined whether measurement of interlead T-wave heterogeneity (TWH) during exercise tolerance testing (ETT) or pharmacologic stress testing improves detection of stenoses in large epicardial coronary arteries. METHODS All 137 patients at our institution who underwent diagnostic coronary angiography within 0 to 5 days after ETT (N = 81) or dipyridamole IV infusion (N = 58) in 2016 were studied, including 2 patients with both tests. Cases (N = 93) had angiographically significant stenosis (≥50% of left main or ≥ 70% of an epicardial coronary artery ≥2 mm in diameter); controls (N = 44) did not. TWH, i.e., interlead splay of T waves, was determined by second central moment analysis from precordial leads by an investigator blinded to angiographic results. RESULTS At rest, TWH levels were similar for cases and controls. ETT and dipyridamole stress testing increased TWH by 69% (p < 0.0001) and 27% (p < 0.0001), respectively, in cases. In controls, TWH did not change. Areas under the ROC curves for TWH increase for any flow-limiting coronary artery stenosis were 0.737 (p < 0.0001) for ETT and 0.818 (p < 0.0001) for dipyridamole stress testing. By contrast, neither ST-segment changes during ETT (p = 0.12) nor MPI during dipyridamole stress testing (p = 0.60) discriminated cases from controls. CONCLUSIONS TWH measurement is a novel method that improves detection of angiographically confirmed flow-limiting stenoses in large epicardial coronary arteries during both ETT and MPI during pharmacologic stress testing with dipyridamole.
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Affiliation(s)
- Anderson C Silva
- Beth Israel Deaconess Medical Center, Department of Medicine, Division of Cardiovascular Medicine, Boston, MA, United States of America; Harvard School of Public Health, Department of Environmental Sciences, Boston, MA, United States of America; Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Victor Z de Antonio
- Beth Israel Deaconess Medical Center, Department of Medicine, Division of Cardiovascular Medicine, Boston, MA, United States of America; Harvard School of Public Health, Department of Environmental Sciences, Boston, MA, United States of America; Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Jakub Sroubek
- Beth Israel Deaconess Medical Center, Department of Medicine, Division of Cardiovascular Medicine, Boston, MA, United States of America; Harvard Medical School, Department of Medicine, Boston, MA, United States of America
| | - Ernest Gervino
- Beth Israel Deaconess Medical Center, Department of Medicine, Division of Cardiovascular Medicine, Boston, MA, United States of America; Harvard Medical School, Department of Medicine, Boston, MA, United States of America
| | - Kalon Ho
- Beth Israel Deaconess Medical Center, Department of Medicine, Division of Cardiovascular Medicine, Boston, MA, United States of America; Harvard Medical School, Department of Medicine, Boston, MA, United States of America
| | - Sofia A Medeiros
- Beth Israel Deaconess Medical Center, Department of Medicine, Division of Cardiovascular Medicine, Boston, MA, United States of America; Harvard School of Public Health, Department of Environmental Sciences, Boston, MA, United States of America; Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Fernanda Tessarolo Silva
- Beth Israel Deaconess Medical Center, Department of Medicine, Division of Cardiovascular Medicine, Boston, MA, United States of America; Harvard School of Public Health, Department of Environmental Sciences, Boston, MA, United States of America; Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Giovanna C Pedreira
- Beth Israel Deaconess Medical Center, Department of Medicine, Division of Cardiovascular Medicine, Boston, MA, United States of America; Harvard School of Public Health, Department of Environmental Sciences, Boston, MA, United States of America; Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Fernando G Stocco
- Beth Israel Deaconess Medical Center, Department of Medicine, Division of Cardiovascular Medicine, Boston, MA, United States of America; Harvard School of Public Health, Department of Environmental Sciences, Boston, MA, United States of America; Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Bruce D Nearing
- Beth Israel Deaconess Medical Center, Department of Medicine, Division of Cardiovascular Medicine, Boston, MA, United States of America; Harvard Medical School, Department of Medicine, Boston, MA, United States of America
| | - Richard L Verrier
- Beth Israel Deaconess Medical Center, Department of Medicine, Division of Cardiovascular Medicine, Boston, MA, United States of America; Harvard School of Public Health, Department of Environmental Sciences, Boston, MA, United States of America; Harvard Medical School, Department of Medicine, Boston, MA, United States of America.
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12
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Aronis KN, Ali RL, Liang JA, Zhou S, Trayanova NA. Understanding AF Mechanisms Through Computational Modelling and Simulations. Arrhythm Electrophysiol Rev 2019; 8:210-219. [PMID: 31463059 PMCID: PMC6702471 DOI: 10.15420/aer.2019.28.2] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 06/17/2019] [Indexed: 12/21/2022] Open
Abstract
AF is a progressive disease of the atria, involving complex mechanisms related to its initiation, maintenance and progression. Computational modelling provides a framework for integration of experimental and clinical findings, and has emerged as an essential part of mechanistic research in AF. The authors summarise recent advancements in development of multi-scale AF models and focus on the mechanistic links between alternations in atrial structure and electrophysiology with AF. Key AF mechanisms that have been explored using atrial modelling are pulmonary vein ectopy; atrial fibrosis and fibrosis distribution; atrial wall thickness heterogeneity; atrial adipose tissue infiltration; development of repolarisation alternans; cardiac ion channel mutations; and atrial stretch with mechano-electrical feedback. They review modelling approaches that capture variability at the cohort level and provide cohort-specific mechanistic insights. The authors conclude with a summary of future perspectives, as envisioned for the contributions of atrial modelling in the mechanistic understanding of AF.
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Affiliation(s)
- Konstantinos N Aronis
- Department of Biomedical Engineering and the Institute for Computational Medicine, Johns Hopkins UniversityBaltimore, MD, US
- Division of Cardiology, Johns Hopkins HospitalBaltimore, MD, US
| | - Rheeda L Ali
- Department of Biomedical Engineering and the Institute for Computational Medicine, Johns Hopkins UniversityBaltimore, MD, US
| | - Jialiu A Liang
- Department of Biomedical Engineering and the Institute for Computational Medicine, Johns Hopkins UniversityBaltimore, MD, US
| | - Shijie Zhou
- Department of Biomedical Engineering and the Institute for Computational Medicine, Johns Hopkins UniversityBaltimore, MD, US
| | - Natalia A Trayanova
- Department of Biomedical Engineering and the Institute for Computational Medicine, Johns Hopkins UniversityBaltimore, MD, US
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13
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Fukaya H, Plummer BN, Piktel JS, Wan X, Rosenbaum DS, Laurita KR, Wilson LD. Arrhythmogenic cardiac alternans in heart failure is suppressed by late sodium current blockade by ranolazine. Heart Rhythm 2019; 16:281-289. [PMID: 30193854 DOI: 10.1016/j.hrthm.2018.08.033] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Indexed: 12/19/2022]
Abstract
BACKGROUND Cardiac alternans is promoted by heart failure (HF)-induced calcium (Ca2+) cycling abnormalities. Late sodium current (INa,L) is enhanced in HF and promotes Ca2+ overload; however, mechanisms underlying an antiarrhythmic effect of INa,L blockade in HF remain unclear. OBJECTIVE The purpose of this study was to determine whether ranolazine suppresses cardiac alternans in HF by normalizing Ca2+ cycling. METHODS Transmural dual optical mapping of Ca2+ transients and action potentials was performed in wedge preparations from 8 HF and 8 control (normal) dogs. Susceptibility to action potential duration alternans (APD-ALT) and Ca2+ transient alternans (Ca-ALT) was compared at baseline and with ranolazine (5-10 μM). RESULTS HF increased APD- and Ca-ALT compared to normal (both P <.05), and ranolazine suppressed APD- and Ca-ALT in both groups (P <.05). The incidence of spatially discordant alternans (DIS-ALT) was increased by HF (8/8) compared to normal (4/8; P <.05), and ranolazine decreased DIS-ALT in HF (4/8; P <.05).Not only did ranolazine mitigate HF-induced Ca2+ overload, it also attenuated APD-ALT to Ca-ALT gain (amount of APD-ALT produced by Ca-ALT). In HF, APD-ALT to Ca-ALT gain was significantly increased (0.55 ± 0.02) compared to normal (0.44 ± 0.02; P <.05) and was normalized by ranolazine (0.36 ± 0.05; P <.05), representing a complementary mechanism by which INa,L blockade suppressed cardiac alternans. CONCLUSION Ranolazine attenuated arrhythmogenic cardiac alternans in HF, both by suppressing Ca-ALT and decreasing the coupling gain of APD-ALT to Ca-ALT. Blockade of INa,L may reverse impaired Ca2+ cycling to mitigate cardiac alternans, representing a mechanism underlying the antiarrhythmic benefit of INa,L blockade in HF.
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Affiliation(s)
- Hidehira Fukaya
- Heart and Vascular Research Center, Case Western Reserve University, Cleveland, Ohio; Department of Cardiovascular Medicine, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Bradley N Plummer
- Heart and Vascular Research Center, Case Western Reserve University, Cleveland, Ohio
| | - Joseph S Piktel
- Heart and Vascular Research Center, Case Western Reserve University, Cleveland, Ohio; Department of Emergency Medicine, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio
| | - Xiaoping Wan
- Heart and Vascular Research Center, Case Western Reserve University, Cleveland, Ohio
| | - David S Rosenbaum
- Heart and Vascular Research Center, Case Western Reserve University, Cleveland, Ohio
| | - Kenneth R Laurita
- Heart and Vascular Research Center, Case Western Reserve University, Cleveland, Ohio
| | - Lance D Wilson
- Heart and Vascular Research Center, Case Western Reserve University, Cleveland, Ohio; Department of Emergency Medicine, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio.
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14
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Aronis KN, Ali R, Trayanova NA. The role of personalized atrial modeling in understanding atrial fibrillation mechanisms and improving treatment. Int J Cardiol 2019; 287:139-147. [PMID: 30755334 DOI: 10.1016/j.ijcard.2019.01.096] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 01/24/2019] [Accepted: 01/28/2019] [Indexed: 12/13/2022]
Abstract
Atrial fibrillation is the most common arrhythmia in humans and is associated with high morbidity, mortality and health-related expenses. Computational approaches have been increasingly utilized in atrial electrophysiology. In this review we summarize the recent advancements in atrial fibrillation modeling at the organ scale. Multi-scale atrial models now incorporate high level detail of atrial anatomy, tissue ultrastructure and fibrosis distribution. We provide the state-of-the art methodologies in developing personalized atrial fibrillation models with realistic geometry and tissue properties. We then focus on the use of multi-scale atrial models to gain mechanistic insights in AF. Simulations using atrial models have provided important insight in the mechanisms underlying AF, showing the importance of the atrial fibrotic substrate and altered atrial electrophysiology in initiation and maintenance of AF. Last, we summarize the translational evidence that supports incorporation of computational modeling in clinical practice for development of personalized treatment strategies for patients with AF. In early-stages clinical studies, AF models successfully identify patients where pulmonary vein isolation alone is not adequate for treatment of AF and suggest novel targets for ablation. We conclude with a summary of the future developments envisioned for the field of atrial computational electrophysiology.
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Affiliation(s)
- Konstantinos N Aronis
- Department of Biomedical Engineering and the Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA; Division of Cardiology, Johns Hopkins Hospital, Baltimore, MD, USA
| | - Rheeda Ali
- Department of Biomedical Engineering and the Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Natalia A Trayanova
- Department of Biomedical Engineering and the Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA.
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15
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Sicouri S, Belardinelli L, Antzelevitch C. Effect of autonomic influences to induce triggered activity in muscular sleeves extending into the coronary sinus of the canine heart and its suppression by ranolazine. J Cardiovasc Electrophysiol 2018; 30:230-238. [PMID: 30302862 DOI: 10.1111/jce.13770] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 10/01/2018] [Accepted: 10/05/2018] [Indexed: 12/19/2022]
Abstract
INTRODUCTION Extrasystoles arising from the muscular sleeves associated with the pulmonary veins (PV), superior vena cava (SVC), and coronary sinus (CS) are known to precipitate atrial fibrillation (AF). The late sodium channel current (INa ) inhibitor ranolazine has been reported to exert antiarrhythmic effects in canine PV and SVC sleeves by suppressing late phase 3 early and delayed after depolarization (EAD and DAD)-induced triggered activity induced by parasympathetic and/or sympathetic stimulation. The current study was designed to extend our existing knowledge of the electrophysiological and pharmacologic properties of canine CS preparations and assess their response to inhibition of late INa following autonomic stimulation. METHODS Transmembrane action potentials were recorded from canine superfused CS using standard microelectrode techniques. Acetylcholine (ACh, 1 µM), isoproterenol (Iso, 1 µM), high calcium ([Ca2+ ]o = 5.4 mM), or a combination were used to induce EADs, DADs, and triggered activity. RESULTS Action potentials (AP) recorded from the CS displayed short and long AP durations (APD), with and without phase 4 depolarization (n = 19). Iso induced DAD-mediated triggered activity. The combination of sympathetic and parasympathetic agonists resulted in late phase 3 EAD-induced triggered activity in all CS preparations. Ranolazine (5-10 µM) suppressed late phase 3 EAD- and DAD-induced triggered activity in 8 of 8 preparations. Subthreshold stimulation induced a prominent hyperpolarization that could be suppressed by atropine. CONCLUSIONS Our results suggest the important role of parasympathetic innervation in the activity of the CS. Autonomic influences promote DAD- and late phase-3-EAD-mediated triggered activity in canine CS, thus generating extrasystolic activity capable of initiating atrial arrhythmias. Ranolazine effectively suppresses these triggers.
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Affiliation(s)
- Serge Sicouri
- Department of Experimental Cardiology, Masonic Medical Research Laboratory, Utica, New York.,Cardiovascular Research Program, Lankenau Institute for Medical Research, Wynnewood, Pennsylvania
| | | | - Charles Antzelevitch
- Department of Experimental Cardiology, Masonic Medical Research Laboratory, Utica, New York.,Cardiovascular Research Program, Lankenau Institute for Medical Research, Wynnewood, Pennsylvania.,Lankenau Heart Institute, Wynnewood, Pennsylvania.,Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania
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El-Bizri N, Xie C, Liu L, Limberis J, Krause M, Hirakawa R, Nguyen S, Tabuena DR, Belardinelli L, Kahlig KM. Eleclazine exhibits enhanced selectivity for long QT syndrome type 3–associated late Na + current. Heart Rhythm 2018; 15:277-286. [DOI: 10.1016/j.hrthm.2017.09.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Indexed: 01/13/2023]
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17
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Pezhouman A, Cao H, Fishbein MC, Belardinelli L, Weiss JN, Karagueuzian HS. Atrial Fibrillation Initiated by Early Afterdepolarization-Mediated Triggered Activity during Acute Oxidative Stress: Efficacy of Late Sodium Current Blockade. ACTA ACUST UNITED AC 2018; 4. [PMID: 30393761 PMCID: PMC6214459 DOI: 10.16966/2379-769x.146] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Background The mechanism of Atrial Fibrillation (AF) that emerges spontaneously during acute oxidative stress is poorly defined and its drug therapy remains suboptimal. We hypothesized that oxidative activation of Ca-calmodulin dependent protein kinase (CaMKII) promotes Early Afterdepolarization-(EAD)-mediated triggered AF in aged fibrotic atria that is sensitive to late Na current (INa-L) blockade. Method and Results High-resolution voltage optical mapping of the Left and Right Atrial (LA & RA) epicardial surfaces along with microelectrode recordings were performed in isolated-perfused male Fisher 344 rat hearts in Langendorff setting. Aged atria (23-24 months) manifested 10-fold increase in atrial tissue fibrosis compared to young/adult (2-4 months) atria (P<0001. Spontaneous AF arose in 39 out of 41 of the aged atria but in 0 out of 12 young/adult hearts (P<001) during arterial perfusion of with 0.1 mm of hydrogen peroxide (H2O2). Optical Action Potential (AP) activation maps showed that the AF was initiated by a focal mechanism in the LA suggestive of EAD-mediated triggered activity. Cellular AP recordings with glass microelectrodes from the LA epicardial sites showing focal activity confirmed optical AP recordings that the spontaneous AF was initiated by late phase 3 EAD-mediated triggered activity. Inhibition of CaMKII activity with KN-93 (1 μM) (N=6) or its downstream target, the enhanced INa-L with GS-967 (1 μM), a specific blocker of INa-L (N=6), potently suppressed the AF and prevented its initiation when perfused 15 min prior to H2O2 (n=6). Conclusions Increased atrial tissue fibrosis combined with acute oxidative activation of CaMK II Initiate AF by EAD-mediated triggered activity. Specific block of the INa-L with GS-967 effectively suppresses the AF. Drug therapy of oxidative AF in humans with traditional antiarrhythmic drugs remains suboptimal; suppressing INa-L offers a potential new strategy for effective suppression of oxidative human AF that remains suboptimal.
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Affiliation(s)
- Arash Pezhouman
- Translational Arrhythmia Section, UCLA Cardiovascular Research Laboratory, USA
| | - Hong Cao
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, PRC
| | | | | | - James N Weiss
- Translational Arrhythmia Section, UCLA Cardiovascular Research Laboratory, USA.,Departments of Medicine (Cardiology), David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Hrayr S Karagueuzian
- Translational Arrhythmia Section, UCLA Cardiovascular Research Laboratory, USA.,Departments of Medicine (Cardiology), David Geffen School of Medicine at UCLA, Los Angeles, California, USA
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Heijman J, Ghezelbash S, Dobrev D. Investigational antiarrhythmic agents: promising drugs in early clinical development. Expert Opin Investig Drugs 2017; 26:897-907. [PMID: 28691539 PMCID: PMC6324729 DOI: 10.1080/13543784.2017.1353601] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
INTRODUCTION Although there have been important technological advances for the treatment of cardiac arrhythmias (e.g., catheter ablation technology), antiarrhythmic drugs (AADs) remain the cornerstone therapy for the majority of patients with arrhythmias. Most of the currently available AADs were coincidental findings and did not result from a systematic development process based on known arrhythmogenic mechanisms and specific targets. During the last 20 years, our understanding of cardiac electrophysiology and fundamental arrhythmia mechanisms has increased significantly, resulting in the identification of new potential targets for mechanism-based antiarrhythmic therapy. Areas covered: Here, we review the state-of-the-art in arrhythmogenic mechanisms and AAD therapy. Thereafter, we focus on a number of antiarrhythmic targets that have received significant attention recently: atrial-specific K+-channels, the late Na+-current, the cardiac ryanodine-receptor channel type-2, and the small-conductance Ca2+-activated K+-channel. We highlight for each of these targets available antiarrhythmic agents and the evidence for their antiarrhythmic effect in animal models and early clinical development. Expert opinion: Targeting AADs to specific subgroups of well-phenotyped patients is likely necessary to detect improved outcomes that may be obscured in the population at large. In addition, specific combinations of selective AADs may have synergistic effects and may enable a mechanism-based tailored antiarrhythmic therapy.
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Affiliation(s)
- Jordi Heijman
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Faculty of Health, Medicine, and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Shokoufeh Ghezelbash
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
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19
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Roberts JD, Soliman EZ, Alonso A, Vittinghoff E, Chen LY, Loehr L, Marcus GM. Electrocardiographic intervals associated with incident atrial fibrillation: Dissecting the QT interval. Heart Rhythm 2017; 14:654-660. [PMID: 28189824 DOI: 10.1016/j.hrthm.2017.02.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Indexed: 02/02/2023]
Abstract
BACKGROUND Prolongation of the QT interval has been associated with an increased risk of developing atrial fibrillation (AF), but the responsible mechanism remains unknown. OBJECTIVES The aims of this study were to subdivide the QT interval into its components and identify the resultant electrocardiographic interval(s) responsible for the association with AF. METHODS Predefined QT-interval components were assessed for association with incident AF in the Atherosclerosis Risk in Communities study using Cox proportional hazards models. Hazard ratios (HRs) were calculated per 1-SD increase in each component. Among QT-interval components exhibiting significant associations, additional analyses evaluating long extremes, defined as greater than the 95th percentile, were performed. RESULTS Of the 14,625 individuals, 1505 (10.3%) were diagnosed with incident AF during a mean follow-up period of 17.6 years. After multivariable adjustment, QT-interval components involved in repolarization, but not depolarization, exhibited significant associations with incident AF, including a longer ST segment (HR 1.27; 95% confidence interval [CI] 1.14-1.41; P < .001) and a prolonged T-wave onset to T-wave peak (T-onset to T-peak) (HR 1.13; 95% CI 1.07-1.20; P < .001). Marked prolongation of the ST segment (HR 1.31; 95% CI 1.04-1.64; P = .022) and T-onset to T-peak (HR 1.36; 95% CI 1.09-1.69; P = .006) was also associated with an increased risk of incident AF. CONCLUSION The association between a prolonged QT interval and incident AF is primarily explained by components involved in ventricular repolarization: prolongation of the ST segment and T-onset to T-peak. These observations suggest that prolongation of phases 2 and 3 of the cardiac action potential drives the association between the QT interval and AF risk.
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Affiliation(s)
- Jason D Roberts
- Section of Cardiac Electrophysiology, Division of Cardiology, Department of Medicine, Western University, London, Ontario, Canada.
| | - Elsayed Z Soliman
- Epidemiological Cardiology Research Center, Wake Forest University School of Medicine, Winston Salem, North Carolina
| | - Alvaro Alonso
- Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia
| | - Eric Vittinghoff
- Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California
| | - Lin Y Chen
- Cardiovascular Division, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Laura Loehr
- Department of Epidemiology, University of North Carolina, Chapel Hill, North Carolina
| | - Gregory M Marcus
- Section of Cardiac Electrophysiology, Division of Cardiology, Department of Medicine, University of California, San Francisco, San Francisco, California.
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20
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Zhang Y, Wang HM, Wang YZ, Zhang YY, Jin XX, Zhao Y, Wang J, Sun YL, Xue GL, Li PH, Huang QH, Yang BF, Pan ZW. Increment of late sodium currents in the left atrial myocytes and its potential contribution to increased susceptibility of atrial fibrillation in castrated male mice. Heart Rhythm 2017; 14:1073-1080. [PMID: 28185917 DOI: 10.1016/j.hrthm.2017.01.046] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Indexed: 12/20/2022]
Abstract
BACKGROUND The incidence of atrial fibrillation (AF) is correlated with decreased levels of testosterone in elderly men. Late sodium current may exert a role in AF pathogenesis. OBJECTIVE The purpose of this study was to explore the effect of testosterone deficiency on AF susceptibility and the therapeutic effect of late sodium current inhibitors in mice. METHODS Male ICR mice (5 weeks old) were castrated to establish a testosterone deficiency model. One month after castration, dihydrotestosterone 5 mg/kg was administered subcutaneously for 2 months. Serum total testosterone level was assessed by enzyme-linked immunosorbent assay. High-frequency electrical stimulation was used to induce atrial arrhythmias. Whole-cell patch-clamp technique was used to for single-cell electrophysiologic study. RESULTS Serum dihydrotestosterone levels of castration mice declined significantly but recovered with administration of exogenous dihydrotestosterone. In comparison with sham mice, the number of AF episodes significantly increased by 13.5-fold, AF rate increased by 3.75-fold, and AF duration prolonged in castrated mice. Dihydrotestosterone administration alleviated the occurrence of AF. Action potential duration at both 50% and 90% repolarization were markedly increased in castrated mice compared to sham controls. The late sodium current was enhanced in castrated male mice. These alterations were alleviated by treatment with dihydrotestosterone. Systemic application of the INa-L inhibitors ranolazine, eleclazine, and GS967 inhibited the occurrence of AF in castrated mice. CONCLUSION Testosterone deficiency contributed to the increased late sodium current, prolonged action potential repolarization, and increased susceptibility to AF. Blocking of late sodium current is beneficial against the occurrence of AF in castrated mice.
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Affiliation(s)
- Yang Zhang
- Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Hui-Min Wang
- Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Ying-Zhe Wang
- Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Yi-Yuan Zhang
- Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Xue-Xin Jin
- Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Yue Zhao
- Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Jin Wang
- Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Yi-Lin Sun
- Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Gen-Long Xue
- Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Peng-Hui Li
- Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Qi-He Huang
- Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Bao-Feng Yang
- Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy Harbin Medical University, Harbin, Heilongjiang, People's Republic of China; Department of Pharmacology and Therapeutics, Melbourne School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, Australia
| | - Zhen-Wei Pan
- Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy Harbin Medical University, Harbin, Heilongjiang, People's Republic of China.
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Bohnen MS, Peng G, Robey SH, Terrenoire C, Iyer V, Sampson KJ, Kass RS. Molecular Pathophysiology of Congenital Long QT Syndrome. Physiol Rev 2017; 97:89-134. [PMID: 27807201 PMCID: PMC5539372 DOI: 10.1152/physrev.00008.2016] [Citation(s) in RCA: 114] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Ion channels represent the molecular entities that give rise to the cardiac action potential, the fundamental cellular electrical event in the heart. The concerted function of these channels leads to normal cyclical excitation and resultant contraction of cardiac muscle. Research into cardiac ion channel regulation and mutations that underlie disease pathogenesis has greatly enhanced our knowledge of the causes and clinical management of cardiac arrhythmia. Here we review the molecular determinants, pathogenesis, and pharmacology of congenital Long QT Syndrome. We examine mechanisms of dysfunction associated with three critical cardiac currents that comprise the majority of congenital Long QT Syndrome cases: 1) IKs, the slow delayed rectifier current; 2) IKr, the rapid delayed rectifier current; and 3) INa, the voltage-dependent sodium current. Less common subtypes of congenital Long QT Syndrome affect other cardiac ionic currents that contribute to the dynamic nature of cardiac electrophysiology. Through the study of mutations that cause congenital Long QT Syndrome, the scientific community has advanced understanding of ion channel structure-function relationships, physiology, and pharmacological response to clinically employed and experimental pharmacological agents. Our understanding of congenital Long QT Syndrome continues to evolve rapidly and with great benefits: genotype-driven clinical management of the disease has improved patient care as precision medicine becomes even more a reality.
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Affiliation(s)
- M S Bohnen
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
| | - G Peng
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
| | - S H Robey
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
| | - C Terrenoire
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
| | - V Iyer
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
| | - K J Sampson
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
| | - R S Kass
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
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Mechanisms of arrhythmogenesis related to calcium-driven alternans in a model of human atrial fibrillation. Sci Rep 2016; 6:36395. [PMID: 27812021 PMCID: PMC5095679 DOI: 10.1038/srep36395] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 10/11/2016] [Indexed: 11/08/2022] Open
Abstract
The occurrence of atrial fibrillation (AF) is associated with progressive changes in the calcium handling system of atrial myocytes. Calcium cycling instability has been implicated as an underlying mechanism of electrical alternans observed in patients who experience AF. However, the extent to which calcium-induced alternation of electrical activity in the atria contributes to arrhythmogenesis is unknown. In this study, we investigated the effects of calcium-driven alternans (CDA) on arrhythmia susceptibility in a biophysically detailed, 3D computer model of the human atria representing electrical and structural remodeling secondary to chronic AF. We found that elevated propensity to CDA rendered the atria vulnerable to ectopy-induced arrhythmia. It also increased the complexity and persistence of arrhythmias induced by fast pacing, with unstable scroll waves meandering and frequently breaking up to produce multiple wavelets. Our results suggest that calcium-induced electrical instability may increase arrhythmia vulnerability and promote increasing disorganization of arrhythmias in the chronic AF-remodeled atria, thus playing an important role in the progression of the disease.
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Justo F, Fuller H, Nearing BD, Rajamani S, Belardinelli L, Verrier RL. Inhibition of the cardiac late sodium current with eleclazine protects against ischemia-induced vulnerability to atrial fibrillation and reduces atrial and ventricular repolarization abnormalities in the absence and presence of concurrent adrenergic stimulation. Heart Rhythm 2016; 13:1860-7. [DOI: 10.1016/j.hrthm.2016.06.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Indexed: 12/19/2022]
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