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Ni H, Morotti S, Zhang X, Dobrev D, Grandi E. Integrative human atrial modelling unravels interactive protein kinase A and Ca2+/calmodulin-dependent protein kinase II signalling as key determinants of atrial arrhythmogenesis. Cardiovasc Res 2023; 119:2294-2311. [PMID: 37523735 PMCID: PMC11318383 DOI: 10.1093/cvr/cvad118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 05/18/2023] [Accepted: 06/05/2023] [Indexed: 08/02/2023] Open
Abstract
AIMS Atrial fibrillation (AF), the most prevalent clinical arrhythmia, is associated with atrial remodelling manifesting as acute and chronic alterations in expression, function, and regulation of atrial electrophysiological and Ca2+-handling processes. These AF-induced modifications crosstalk and propagate across spatial scales creating a complex pathophysiological network, which renders AF resistant to existing pharmacotherapies that predominantly target transmembrane ion channels. Developing innovative therapeutic strategies requires a systems approach to disentangle quantitatively the pro-arrhythmic contributions of individual AF-induced alterations. METHODS AND RESULTS Here, we built a novel computational framework for simulating electrophysiology and Ca2+-handling in human atrial cardiomyocytes and tissues, and their regulation by key upstream signalling pathways [i.e. protein kinase A (PKA), and Ca2+/calmodulin-dependent protein kinase II (CaMKII)] involved in AF-pathogenesis. Populations of atrial cardiomyocyte models were constructed to determine the influence of subcellular ionic processes, signalling components, and regulatory networks on atrial arrhythmogenesis. Our results reveal a novel synergistic crosstalk between PKA and CaMKII that promotes atrial cardiomyocyte electrical instability and arrhythmogenic triggered activity. Simulations of heterogeneous tissue demonstrate that this cellular triggered activity is further amplified by CaMKII- and PKA-dependent alterations of tissue properties, further exacerbating atrial arrhythmogenesis. CONCLUSIONS Our analysis reveals potential mechanisms by which the stress-associated adaptive changes turn into maladaptive pro-arrhythmic triggers at the cellular and tissue levels and identifies potential anti-AF targets. Collectively, our integrative approach is powerful and instrumental to assemble and reconcile existing knowledge into a systems network for identifying novel anti-AF targets and innovative approaches moving beyond the traditional ion channel-based strategy.
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Affiliation(s)
- Haibo Ni
- Department of Pharmacology, University of California Davis,
451 Health Sciences Drive, Davis, CA 95616, USA
| | - Stefano Morotti
- Department of Pharmacology, University of California Davis,
451 Health Sciences Drive, Davis, CA 95616, USA
| | - Xianwei Zhang
- Department of Pharmacology, University of California Davis,
451 Health Sciences Drive, Davis, CA 95616, USA
| | - Dobromir Dobrev
- Institute of Pharmacology, Faculty of Medicine, University
Duisburg-Essen, Essen, Germany
- Department of Medicine and Research Center, Montreal Heart Institute and
Université de Montréal, Montréal, Canada
- Department of Molecular Physiology and Biophysics, Baylor College of
Medicine, Houston, TX, USA
| | - Eleonora Grandi
- Department of Pharmacology, University of California Davis,
451 Health Sciences Drive, Davis, CA 95616, USA
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2
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Tourni M, Han SJ, Weber R, Kucinski M, Wan EY, Biviano AB, Konofagou EE. Electromechanical Cycle Length Mapping for atrial arrhythmia detection and cardioversion success assessment. Comput Biol Med 2023; 163:107084. [PMID: 37302374 PMCID: PMC10527498 DOI: 10.1016/j.compbiomed.2023.107084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 04/26/2023] [Accepted: 05/27/2023] [Indexed: 06/13/2023]
Abstract
BACKGROUND Direct current cardioversion (DCCV) is an established treatment to acutely convert atrial fibrillation (AF) to normal sinus rhythm. Yet, more than 70% of patients revert to AF shortly thereafter. Electromechanical Cycle Length Mapping (ECLM) is a high framerate, spectral analysis technique shown to non-invasively characterize electromechanical activation in paced canines and re-entrant flutter patients. This study assesses ECLM feasibility to map and quantify atrial arrhythmic electromechanical activation rates and inform on 1-day and 1-month DCCV response. METHODS Forty-five subjects (30 AF; 15 healthy sinus rhythm (SR) controls) underwent transthoracic ECLM in four standard apical 2D echocardiographic views. AF patients were imaged within 1 h pre- and post-DCCV. 3D-rendered atrial ECLM cycle length (CL) maps and spatial CL histograms were generated. CL dispersion and percentage of arrhythmic CLs≤333ms across the entire atrial myocardium were computed transmurally. ECLM results were subsequently used as indicators of DCCV success. RESULTS ECLM successfully confirmed the electrical atrial activation rates in 100% of healthy subjects (R2=0.96). In AF, ECLM maps localized the irregular activation rates pre-DCCV and confirmed successful post-DCCV with immediate reduction or elimination. ECLM metrics successfully distinguished DCCV 1-day and 1-month responders from non-responders, while pre-DCCV ECLM values independently predicted AF recurrence within 1-month post-DCCV. CONCLUSIONS ECLM can characterize electromechanical activation rates in AF, quantify their extent, and identify and predict short- and long-term AF recurrence. ELCM constitutes thus a noninvasive arrhythmia imaging modality that can aid clinicians in simultaneous AF severity quantification, prediction of AF DCCV response, and personalized treatment planning.
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Affiliation(s)
- Melina Tourni
- Depatrment of Biomedical Engineering, Columbia University, 630 W 168th Street, New York, 10032, NY, USA.
| | - Seungyeon Julia Han
- Depatrment of Biomedical Engineering, Columbia University, 630 W 168th Street, New York, 10032, NY, USA
| | - Rachel Weber
- Depatrment of Biomedical Engineering, Columbia University, 630 W 168th Street, New York, 10032, NY, USA
| | - Mary Kucinski
- Depatrment of Biomedical Engineering, Columbia University, 630 W 168th Street, New York, 10032, NY, USA
| | - Elaine Y Wan
- Department of Medicine and Vagelos College of Physicians and Surgeons, Columbia University, 630 W 168th Street, New York, 10032, NY, USA
| | - Angelo B Biviano
- Department of Medicine and Vagelos College of Physicians and Surgeons, Columbia University, 630 W 168th Street, New York, 10032, NY, USA
| | - Elisa E Konofagou
- Depatrment of Biomedical Engineering, Columbia University, 630 W 168th Street, New York, 10032, NY, USA; Department of Radiology, Columbia University, 630 W 168th Street, New York, 10032, NY, USA.
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3
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Zhang X, Ni H, Morotti S, Smith C, Sato D, Louch W, Edwards A, Grandi E. Mechanisms of spontaneous Ca 2+ release-mediated arrhythmia in a novel 3D human atrial myocyte model: I. Transverse-axial tubule variation. J Physiol 2023; 601:2655-2683. [PMID: 36094888 PMCID: PMC10008525 DOI: 10.1113/jp283363] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 09/02/2022] [Indexed: 11/08/2022] Open
Abstract
Intracellular calcium (Ca2+ ) cycling is tightly regulated in the healthy heart ensuring effective contraction. This is achieved by transverse (t)-tubule membrane invaginations that facilitate close coupling of key Ca2+ -handling proteins such as the L-type Ca2+ channel and Na+ -Ca2+ exchanger (NCX) on the cell surface with ryanodine receptors (RyRs) on the intracellular Ca2+ store. Although less abundant and regular than in the ventricle, t-tubules also exist in atrial myocytes as a network of transverse invaginations with axial extensions known as the transverse-axial tubule system (TATS). In heart failure and atrial fibrillation, there is TATS remodelling that is associated with aberrant Ca2+ -handling and Ca2+ -induced arrhythmic activity; however, the mechanism underlying this is not fully understood. To address this, we developed a novel 3D human atrial myocyte model that couples electrophysiology and Ca2+ -handling with variable TATS organization and density. We extensively parameterized and validated our model against experimental data to build a robust tool examining TATS regulation of subcellular Ca2+ release. We found that varying TATS density and thus the localization of key Ca2+ -handling proteins has profound effects on Ca2+ handling. Following TATS loss, there is reduced NCX that results in increased cleft Ca2+ concentration through decreased Ca2+ extrusion. This elevated Ca2+ increases RyR open probability causing spontaneous Ca2+ releases and the promotion of arrhythmogenic waves (especially in the cell interior) leading to voltage instabilities through delayed afterdepolarizations. In summary, the present study demonstrates a mechanistic link between TATS remodelling and Ca2+ -driven proarrhythmic behaviour that probably reflects the arrhythmogenic state observed in disease. KEY POINTS: Transverse-axial tubule systems (TATS) modulate Ca2+ handling and excitation-contraction coupling in atrial myocytes, with TATS remodelling in heart failure and atrial fibrillation being associated with altered Ca2+ cycling and subsequent arrhythmogenesis. To investigate the poorly understood mechanisms linking TATS variation and spontaneous Ca2+ release, we built, parameterized and validated a 3D human atrial myocyte model coupling electrophysiology and spatially-detailed subcellular Ca2+ handling governed by the TATS. Simulated TATS loss causes diastolic Ca2+ and voltage instabilities through reduced Na+ -Ca2+ exchanger-mediated Ca2+ removal, cleft Ca2+ accumulation and increased ryanodine receptor open probability, resulting in spontaneous Ca2+ release and promotion of arrhythmogenic waves and delayed afterdepolarizations. At fast electrical rates typical of atrial tachycardia/fibrillation, spontaneous Ca2+ releases are larger and more frequent in the cell interior than at the periphery. Our work provides mechanistic insight into how atrial TATS remodelling can lead to Ca2+ -driven instabilities that may ultimately contribute to the arrhythmogenic state in disease.
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Affiliation(s)
- X. Zhang
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - H. Ni
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - S. Morotti
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - C.E.R. Smith
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - D. Sato
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - W.E. Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo Norway
| | - A.G. Edwards
- Department of Pharmacology, University of California Davis, Davis, CA, USA
- Simula Research Laboratory, Lysaker, Norway
| | - E. Grandi
- Department of Pharmacology, University of California Davis, Davis, CA, USA
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4
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Moise N, Weinberg SH. Emergent activity, heterogeneity, and robustness in a calcium feedback model of the sinoatrial node. Biophys J 2023; 122:1613-1632. [PMID: 36945778 PMCID: PMC10183324 DOI: 10.1016/j.bpj.2023.03.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 02/16/2023] [Accepted: 03/15/2023] [Indexed: 03/23/2023] Open
Abstract
The sinoatrial node (SAN) is the primary pacemaker of the heart. SAN activity emerges at an early point in life and maintains a steady rhythm for the lifetime of the organism. The ion channel composition and currents of SAN cells can be influenced by a variety of factors. Therefore, the emergent activity and long-term stability imply some form of dynamical feedback control of SAN activity. We adapt a recent feedback model-previously utilized to describe control of ion conductances in neurons-to a model of SAN cells and tissue. The model describes a minimal regulatory mechanism of ion channel conductances via feedback between intracellular calcium and an intrinsic target calcium level. By coupling a SAN cell to the calcium feedback model, we show that spontaneous electrical activity emerges from quiescence and is maintained at steady state. In a 2D SAN tissue model, spatial variability in intracellular calcium targets lead to significant, self-organized heterogeneous ion channel expression and calcium transients throughout the tissue. Furthermore, multiple pacemaking regions appear, which interact and lead to time-varying cycle length, demonstrating that variability in heart rate is an emergent property of the feedback model. Finally, we demonstrate that the SAN tissue is robust to the silencing of leading cells or ion channel knockouts. Thus, the calcium feedback model can reproduce and explain many fundamental emergent properties of activity in the SAN that have been observed experimentally based on a minimal description of intracellular calcium and ion channel regulatory networks.
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Affiliation(s)
- Nicolae Moise
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio; Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Seth H Weinberg
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio; Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio.
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Schulz C, Lemoine MD, Mearini G, Koivumäki J, Sani J, Schwedhelm E, Kirchhof P, Ghalawinji A, Stoll M, Hansen A, Eschenhagen T, Christ T. PITX2 Knockout Induces Key Findings of Electrical Remodeling as Seen in Persistent Atrial Fibrillation. Circ Arrhythm Electrophysiol 2023; 16:e011602. [PMID: 36763906 DOI: 10.1161/circep.122.011602] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
BACKGROUND Electrical remodeling in human persistent atrial fibrillation is believed to result from rapid electrical activation of the atria, but underlying genetic causes may contribute. Indeed, common gene variants in an enhancer region close to PITX2 (paired-like homeodomain transcription factor 2) are strongly associated with atrial fibrillation, but the mechanism behind this association remains unknown. This study evaluated the consequences of PITX2 deletion (PITX2-/-) in human induced pluripotent stem cell-derived atrial cardiomyocytes. METHODS CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/clustered regularly interspaced short palindromic repeat-associated 9) was used to delete PITX2 in a healthy human iPSC line that served as isogenic control. Human induced pluripotent stem cell-derived atrial cardiomyocytes were differentiated with unfiltered retinoic acid and cultured in atrial engineered heart tissue. Force and action potential were measured in atrial engineered heart tissues. Single human induced pluripotent stem cell-derived atrial cardiomyocytes were isolated from atrial engineered heart tissue for ion current measurements. RESULTS PITX2-/- atrial engineered heart tissue beats slightly slower than isogenic control without irregularity. Force was lower in PITX2-/- than in isogenic control (0.053±0.015 versus 0.131±0.017 mN, n=28/3 versus n=28/4, PITX2-/- versus isogenic control; P<0.0001), accompanied by lower expression of CACNA1C and lower L-type Ca2+ current density. Early repolarization was weaker (action potential duration at 20% repolarization; 45.5±13.2 versus 8.6±5.3 ms, n=18/3 versus n=12/4, PITX2-/- versus isogenic control; P<0.0001), and maximum diastolic potential was more negative (-78.3±3.1 versus -69.7±0.6 mV, n=18/3 versus n=12/4, PITX2-/- versus isogenic control; P=0.001), despite normal inward rectifier currents (both IK1 and IK,ACh) and carbachol-induced shortening of action potential duration. CONCLUSIONS Complete PITX2 deficiency in human induced pluripotent stem cell-derived atrial cardiomyocytes recapitulates some findings of electrical remodeling of atrial fibrillation in the absence of fast beating, indicating that these abnormalities could be primary consequences of lower PITX2 levels.
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Affiliation(s)
- Carl Schulz
- Institute of Experimental Pharmacology and Toxicology (C.S., M.D.L., G.M., J.S., A.H., T.E., T.C.), University Medical Center Hamburg-Eppendorf, Germany
- German Center for Cardiovascular Research, Partner Site Hamburg/Kiel/Lübeck (C.S., M.D.L., G.M., J.S., E.S., P.K.)
| | - Marc D Lemoine
- Institute of Experimental Pharmacology and Toxicology (C.S., M.D.L., G.M., J.S., A.H., T.E., T.C.), University Medical Center Hamburg-Eppendorf, Germany
- German Center for Cardiovascular Research, Partner Site Hamburg/Kiel/Lübeck (C.S., M.D.L., G.M., J.S., E.S., P.K.)
- Department of Cardiology, University Heart and Vascular Center, Hamburg, Germany (M.D.L., A.H., P.K., T.E., T.C.)
| | - Giulia Mearini
- Institute of Experimental Pharmacology and Toxicology (C.S., M.D.L., G.M., J.S., A.H., T.E., T.C.), University Medical Center Hamburg-Eppendorf, Germany
- German Center for Cardiovascular Research, Partner Site Hamburg/Kiel/Lübeck (C.S., M.D.L., G.M., J.S., E.S., P.K.)
- DiNAQOR AG, Pfäffikon, Switzerland (G.M., P.K.)
| | - Jussi Koivumäki
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Finland (J.K.)
| | - Jascha Sani
- Institute of Experimental Pharmacology and Toxicology (C.S., M.D.L., G.M., J.S., A.H., T.E., T.C.), University Medical Center Hamburg-Eppendorf, Germany
- German Center for Cardiovascular Research, Partner Site Hamburg/Kiel/Lübeck (C.S., M.D.L., G.M., J.S., E.S., P.K.)
| | - Edzard Schwedhelm
- Institute of Clinical Pharmacology and Toxicology (E.S.), University Medical Center Hamburg-Eppendorf, Germany
- German Center for Cardiovascular Research, Partner Site Hamburg/Kiel/Lübeck (C.S., M.D.L., G.M., J.S., E.S., P.K.)
| | - Paulus Kirchhof
- German Center for Cardiovascular Research, Partner Site Hamburg/Kiel/Lübeck (C.S., M.D.L., G.M., J.S., E.S., P.K.)
- Department of Cardiology, University Heart and Vascular Center, Hamburg, Germany (M.D.L., A.H., P.K., T.E., T.C.)
- DiNAQOR AG, Pfäffikon, Switzerland (G.M., P.K.)
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, United Kingdom (P.K.)
| | - Amer Ghalawinji
- Division of Genetic Epidemiology, Institute of Human Genetics, University of Münster, Germany (A.G., M.S.)
| | - Monika Stoll
- Division of Genetic Epidemiology, Institute of Human Genetics, University of Münster, Germany (A.G., M.S.)
- Department of Biochemistry, CARIM School for Cardiovascular Sciences, Maastricht University, the Netherlands (M.S.)
| | - Arne Hansen
- Institute of Experimental Pharmacology and Toxicology (C.S., M.D.L., G.M., J.S., A.H., T.E., T.C.), University Medical Center Hamburg-Eppendorf, Germany
- Department of Cardiology, University Heart and Vascular Center, Hamburg, Germany (M.D.L., A.H., P.K., T.E., T.C.)
| | - Thomas Eschenhagen
- Institute of Experimental Pharmacology and Toxicology (C.S., M.D.L., G.M., J.S., A.H., T.E., T.C.), University Medical Center Hamburg-Eppendorf, Germany
- Department of Cardiology, University Heart and Vascular Center, Hamburg, Germany (M.D.L., A.H., P.K., T.E., T.C.)
| | - Torsten Christ
- Institute of Experimental Pharmacology and Toxicology (C.S., M.D.L., G.M., J.S., A.H., T.E., T.C.), University Medical Center Hamburg-Eppendorf, Germany
- Department of Cardiology, University Heart and Vascular Center, Hamburg, Germany (M.D.L., A.H., P.K., T.E., T.C.)
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Patel RS, Khayata M, De Ponti R, Bagliani G, Leonelli FM. Relationships Between Atrial Flutter and Fibrillation: The Border Zone. Card Electrophysiol Clin 2022; 14:421-434. [PMID: 36153124 DOI: 10.1016/j.ccep.2022.06.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
Abstract
Atrial flutter and fibrillation have been inextricably linked in the study of electrophysiology. With astute clinical observation, advanced diagnostic equipment in the Electrophysiology Laboratory, and thoughtful study of animal models, the mechanism and inter-relationship between the 2 conditions have been elucidated and will be reviewed in this article. Though diagnosis and management of these conditions have many similarities, the mechanisms by which they develop and persist are quite unique.
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Affiliation(s)
- Ritesh S Patel
- University of South Florida Morsani, College of Medicine, Division of Cardiovascular Diseases, 4202 E Fowler Avenue, Tampa, FL 33620, USA
| | - Mohamed Khayata
- University of South Florida Morsani, College of Medicine, Division of Cardiovascular Diseases, 4202 E Fowler Avenue, Tampa, FL 33620, USA
| | - Roberto De Ponti
- Department of Heart and Vessels, Ospedale di Circolo, Viale Borri, 57, 21100, Varese, Italy; Department of Medicine and Surgery, University of Insubria, Viale Guicciardini, 9, 21100, Varese, Italy
| | - Giuseppe Bagliani
- Cardiology And Arrhythmology Clinic, University Hospital "Ospedali Riuniti", Via Conca 71, 60126, Ancona, Italy; Department of Biomedical Sciences and Public Health, Marche Polytechnic University, Via Conca 71, 60126, Ancona, Italy
| | - Fabio M Leonelli
- University of South Florida Morsani, College of Medicine, Division of Cardiovascular Diseases, 4202 E Fowler Avenue, Tampa, FL 33620, USA; James A Haley Veterans Hospital, Tampa, FL, USA.
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7
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Emerging Antiarrhythmic Drugs for Atrial Fibrillation. Int J Mol Sci 2022; 23:ijms23084096. [PMID: 35456912 PMCID: PMC9029767 DOI: 10.3390/ijms23084096] [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: 02/28/2022] [Revised: 03/28/2022] [Accepted: 04/01/2022] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF), the most common cardiac arrhythmia worldwide, is driven by complex mechanisms that differ between subgroups of patients. This complexity is apparent from the different forms in which AF presents itself (post-operative, paroxysmal and persistent), each with heterogeneous patterns and variable progression. Our current understanding of the mechanisms responsible for initiation, maintenance and progression of the different forms of AF has increased significantly in recent years. Nevertheless, antiarrhythmic drugs for the management of AF have not been developed based on the underlying arrhythmia mechanisms and none of the currently used drugs were specifically developed to target AF. With the increased knowledge on the mechanisms underlying different forms of AF, new opportunities for developing more effective and safer AF therapies are emerging. In this review, we provide an overview of potential novel antiarrhythmic approaches based on the underlying mechanisms of AF, focusing both on the development of novel antiarrhythmic agents and on the possibility of repurposing already marketed drugs. In addition, we discuss the opportunity of targeting some of the key players involved in the underlying AF mechanisms, such as ryanodine receptor type-2 (RyR2) channels and atrial-selective K+-currents (IK2P and ISK) for antiarrhythmic therapy. In addition, we highlight the opportunities for targeting components of inflammatory signaling (e.g., the NLRP3-inflammasome) and upstream mechanisms targeting fibroblast function to prevent structural remodeling and progression of AF. Finally, we critically appraise emerging antiarrhythmic drug principles and future directions for antiarrhythmic drug development, as well as their potential for improving AF management.
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8
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Della Rocca DG, Di Biase L, Mohanty S, Trivedi C, Gianni C, Romero J, Tarantino N, Magnocavallo M, Bassiouny M, Natale VN, Mayedo AQ, Macdonald B, Lavalle C, Murtaza G, Akella K, Forleo GB, Al-Ahmad A, Burkhardt JD, Gallinghouse GJ, Sanchez JE, Horton RP, Viles-Gonzalez JF, Lakkireddy D, Natale A. Targeting non-pulmonary vein triggers in persistent atrial fibrillation: results from a prospective, multicentre, observational registry. Europace 2021; 23:1939-1949. [PMID: 34417816 DOI: 10.1093/europace/euab161] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 06/14/2021] [Indexed: 11/13/2022] Open
Abstract
AIMS We evaluated the efficacy of an ablation strategy empirically targeting pulmonary veins (PVs) and posterior wall (PW) and the prevalence and clinical impact of extrapulmonary trigger inducibility and ablation in a large cohort of patients with persistent atrial fibrillation (PerAF). METHODS AND RESULTS A total of 1803 PerAF patients were prospectively enrolled. All patients underwent pulmonary vein antrum isolation (PVAI) extended to the entire PW. A standardized protocol was performed to confirm persistent PVAI and elicit any triggers originating from non-PV sites. All non-PV triggers initiating sustained atrial tachyarrhythmias were ablated. Ablation of non-PV sites triggering non-sustained runs (<30 s) of atrial tachyarrhythmias or promoting frequent premature atrial complexes (≥10/min) was left to operator's discretion. Overall, 1319 (73.2%) patients had documented triggers from non-PV areas. After 17.4 ± 8.5 months of follow-up, the cumulative freedom from atrial tachyarrhythmias among patients without inducible non-PV triggers (n = 484) was 70.2%. Patients with ablation of induced non-PV triggers had a significantly higher arrhythmia control than those whose triggers were not ablated (67.9% vs. 39.4%, respectively; P < 0.001). After adjusting for clinically relevant variables, patients in whom non-PV triggers were documented but not ablated had an increased risk of arrhythmia relapse (hazard ratio: 2.39; 95% confidence interval: 2.01-2.83; P < 0.001). CONCLUSION Pulmonary vein antrum isolation extended to the entire PW might provide acceptable long-term arrhythmia-free survival in PerAF patients without inducible non-PV triggers. In our population of PerAF patients, non-PV triggers could be elicited in ∼70% of PerAF patients and their elimination significantly improved outcomes.
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Affiliation(s)
- Domenico G Della Rocca
- Texas Cardiac Arrhythmia Institute, St. David's Medical Center, 3000 N. IH-35, Suite 720, Austin, TX 78705, USA
| | - Luigi Di Biase
- Texas Cardiac Arrhythmia Institute, St. David's Medical Center, 3000 N. IH-35, Suite 720, Austin, TX 78705, USA.,Department of Internal Medicine, Dell Medical School, University of Texas, Austin, TX, USA.,Department of Biomedical Engineering, Cockrell School of Engineering, University of Texas, Austin, TX, USA.,Arrhythmia Services, Department of Medicine, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY, USA.,Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | - Sanghamitra Mohanty
- Texas Cardiac Arrhythmia Institute, St. David's Medical Center, 3000 N. IH-35, Suite 720, Austin, TX 78705, USA
| | - Chintan Trivedi
- Texas Cardiac Arrhythmia Institute, St. David's Medical Center, 3000 N. IH-35, Suite 720, Austin, TX 78705, USA
| | - Carola Gianni
- Texas Cardiac Arrhythmia Institute, St. David's Medical Center, 3000 N. IH-35, Suite 720, Austin, TX 78705, USA
| | - Jorge Romero
- Arrhythmia Services, Department of Medicine, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Nicola Tarantino
- Arrhythmia Services, Department of Medicine, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Michele Magnocavallo
- Department of Cardiovascular, Respiratory, Nephrology, Anesthesiology and Geriatric Sciences, Sapienza University of Rome, Viale del Policlinico 155, 00161 Rome, Italy
| | - Mohamed Bassiouny
- Texas Cardiac Arrhythmia Institute, St. David's Medical Center, 3000 N. IH-35, Suite 720, Austin, TX 78705, USA
| | - Veronica N Natale
- Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Angel Quintero Mayedo
- Texas Cardiac Arrhythmia Institute, St. David's Medical Center, 3000 N. IH-35, Suite 720, Austin, TX 78705, USA
| | - Bryan Macdonald
- Texas Cardiac Arrhythmia Institute, St. David's Medical Center, 3000 N. IH-35, Suite 720, Austin, TX 78705, USA
| | - Carlo Lavalle
- Department of Cardiovascular, Respiratory, Nephrology, Anesthesiology and Geriatric Sciences, Sapienza University of Rome, Viale del Policlinico 155, 00161 Rome, Italy
| | - Ghulam Murtaza
- Cardiovascular Research Institute, Kansas University Hospital, Kansas City, KS, USA
| | - Krishna Akella
- Cardiovascular Research Institute, Kansas University Hospital, Kansas City, KS, USA
| | | | - Amin Al-Ahmad
- Texas Cardiac Arrhythmia Institute, St. David's Medical Center, 3000 N. IH-35, Suite 720, Austin, TX 78705, USA
| | - John David Burkhardt
- Texas Cardiac Arrhythmia Institute, St. David's Medical Center, 3000 N. IH-35, Suite 720, Austin, TX 78705, USA
| | - Gerald Joseph Gallinghouse
- Texas Cardiac Arrhythmia Institute, St. David's Medical Center, 3000 N. IH-35, Suite 720, Austin, TX 78705, USA
| | - Javier E Sanchez
- Texas Cardiac Arrhythmia Institute, St. David's Medical Center, 3000 N. IH-35, Suite 720, Austin, TX 78705, USA
| | - Rodney P Horton
- Texas Cardiac Arrhythmia Institute, St. David's Medical Center, 3000 N. IH-35, Suite 720, Austin, TX 78705, USA
| | | | | | - Andrea Natale
- Texas Cardiac Arrhythmia Institute, St. David's Medical Center, 3000 N. IH-35, Suite 720, Austin, TX 78705, USA.,Department of Internal Medicine, Dell Medical School, University of Texas, Austin, TX, USA.,Department of Biomedical Engineering, Cockrell School of Engineering, University of Texas, Austin, TX, USA.,Interventional Electrophysiology, Scripps Clinic, La Jolla, CA, USA.,Department of Cardiology, MetroHealth Medical Center, Case Western Reserve University School of Medicine, Cleveland, OH, USA.,Division of Cardiology, Stanford University, Stanford, CA, USA
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9
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Abstract
The physiological heart function is controlled by a well-orchestrated interplay of different ion channels conducting Na+, Ca2+ and K+. Cardiac K+ channels are key players of cardiac repolarization counteracting depolarizating Na+ and Ca2+ currents. In contrast to Na+ and Ca2+, K+ is conducted by many different channels that differ in activation/deactivation kinetics as well as in their contribution to different phases of the action potential. Together with modulatory subunits these K+ channel α-subunits provide a wide range of repolarizing currents with specific characteristics. Moreover, due to expression differences, K+ channels strongly influence the time course of the action potentials in different heart regions. On the other hand, the variety of different K+ channels increase the number of possible disease-causing mutations. Up to now, a plethora of gain- as well as loss-of-function mutations in K+ channel forming or modulating proteins are known that cause severe congenital cardiac diseases like the long-QT-syndrome, the short-QT-syndrome, the Brugada syndrome and/or different types of atrial tachyarrhythmias. In this chapter we provide a comprehensive overview of different K+ channels in cardiac physiology and pathophysiology.
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10
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Belletti R, Romero L, Martinez-Mateu L, Cherry EM, Fenton FH, Saiz J. Arrhythmogenic Effects of Genetic Mutations Affecting Potassium Channels in Human Atrial Fibrillation: A Simulation Study. Front Physiol 2021; 12:681943. [PMID: 34135774 PMCID: PMC8201780 DOI: 10.3389/fphys.2021.681943] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 05/05/2021] [Indexed: 11/16/2022] Open
Abstract
Genetic mutations in genes encoding for potassium channel protein structures have been recently associated with episodes of atrial fibrillation in asymptomatic patients. The aim of this study is to investigate the potential arrhythmogenicity of three gain-of-function mutations related to atrial fibrillation-namely, KCNH2 T895M, KCNH2 T436M, and KCNE3-V17M-using modeling and simulation of the electrophysiological activity of the heart. A genetic algorithm was used to tune the parameters' value of the original ionic currents to reproduce the alterations experimentally observed caused by the mutations. The effects on action potentials, ionic currents, and restitution properties were analyzed using versions of the Courtemanche human atrial myocyte model in different tissues: pulmonary vein, right, and left atrium. Atrial susceptibility of the tissues to spiral wave generation was also investigated studying the temporal vulnerability. The presence of the three mutations resulted in an overall more arrhythmogenic substrate. Higher current density, action potential duration shortening, and flattening of the restitution curves were the major effects of the three mutations at the single-cell level. The genetic mutations at the tissue level induced a higher temporal vulnerability to the rotor's initiation and progression, by sustaining spiral waves that perpetuate until the end of the simulation. The mutation with the highest pro-arrhythmic effects, exhibiting the widest sustained VW and the smallest meandering rotor's tip areas, was KCNE3-V17M. Moreover, the increased susceptibility to arrhythmias and rotor's stability was tissue-dependent. Pulmonary vein tissues were more prone to rotor's initiation, while in left atrium tissues rotors were more easily sustained. Re-entries were also progressively more stable in pulmonary vein tissue, followed by the left atrium, and finally the right atrium. The presence of the genetic mutations increased the susceptibility to arrhythmias by promoting the rotor's initiation and maintenance. The study provides useful insights into the mechanisms underlying fibrillatory events caused by KCNH2 T895M, KCNH2 T436M, and KCNE3-V17M and might aid the planning of patient-specific targeted therapies.
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Affiliation(s)
- Rebecca Belletti
- Centro de Investigación e Innovación en Bioingeniería, Universitat Politècnica de València, Valencia, Spain
| | - Lucia Romero
- Centro de Investigación e Innovación en Bioingeniería, Universitat Politècnica de València, Valencia, Spain
| | - Laura Martinez-Mateu
- Departamento de Teoría de la Señal y Comunicaciones y Sistemas Telemáticos y Computación, Universidad Rey Juan Carlos, Madrid, Spain
| | - Elizabeth M. Cherry
- School of Computational Science and Engineering, Georgia Institute of Technology, Atlanta, GA, United States
| | - Flavio H. Fenton
- School of Physics, Georgia Institute of Technology, Atlanta, GA, United States
| | - Javier Saiz
- Centro de Investigación e Innovación en Bioingeniería, Universitat Politècnica de València, Valencia, Spain
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11
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Nothstein M, Luik A, Jadidi A, Sánchez J, Unger LA, Wülfers EM, Dössel O, Seemann G, Schmitt C, Loewe A. CVAR-Seg: An Automated Signal Segmentation Pipeline for Conduction Velocity and Amplitude Restitution. Front Physiol 2021; 12:673047. [PMID: 34108887 PMCID: PMC8181407 DOI: 10.3389/fphys.2021.673047] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 04/30/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Rate-varying S1S2 stimulation protocols can be used for restitution studies to characterize atrial substrate, ionic remodeling, and atrial fibrillation risk. Clinical restitution studies with numerous patients create large amounts of these data. Thus, an automated pipeline to evaluate clinically acquired S1S2 stimulation protocol data necessitates consistent, robust, reproducible, and precise evaluation of local activation times, electrogram amplitude, and conduction velocity. Here, we present the CVAR-Seg pipeline, developed focusing on three challenges: (i) No previous knowledge of the stimulation parameters is available, thus, arbitrary protocols are supported. (ii) The pipeline remains robust under different noise conditions. (iii) The pipeline supports segmentation of atrial activities in close temporal proximity to the stimulation artifact, which is challenging due to larger amplitude and slope of the stimulus compared to the atrial activity. METHODS AND RESULTS The S1 basic cycle length was estimated by time interval detection. Stimulation time windows were segmented by detecting synchronous peaks in different channels surpassing an amplitude threshold and identifying time intervals between detected stimuli. Elimination of the stimulation artifact by a matched filter allowed detection of local activation times in temporal proximity. A non-linear signal energy operator was used to segment periods of atrial activity. Geodesic and Euclidean inter electrode distances allowed approximation of conduction velocity. The automatic segmentation performance of the CVAR-Seg pipeline was evaluated on 37 synthetic datasets with decreasing signal-to-noise ratios. Noise was modeled by reconstructing the frequency spectrum of clinical noise. The pipeline retained a median local activation time error below a single sample (1 ms) for signal-to-noise ratios as low as 0 dB representing a high clinical noise level. As a proof of concept, the pipeline was tested on a CARTO case of a paroxysmal atrial fibrillation patient and yielded plausible restitution curves for conduction speed and amplitude. CONCLUSION The proposed openly available CVAR-Seg pipeline promises fast, fully automated, robust, and accurate evaluations of atrial signals even with low signal-to-noise ratios. This is achieved by solving the proximity problem of stimulation and atrial activity to enable standardized evaluation without introducing human bias for large data sets.
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Affiliation(s)
- Mark Nothstein
- Institute of Biomedical Engineering (IBT), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Armin Luik
- Medizinische Klinik IV, Städtisches Klinikum Karlsruhe, Karlsruhe, Germany
| | - Amir Jadidi
- Klinik für Kardiologie und Angiologie II, University Heart Center Freiburg-Bad Krozingen, Bad Krozingen, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Jorge Sánchez
- Institute of Biomedical Engineering (IBT), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Laura A. Unger
- Institute of Biomedical Engineering (IBT), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Eike M. Wülfers
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg-Bad Krozingen, Freiburg, Germany
| | - Olaf Dössel
- Institute of Biomedical Engineering (IBT), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Gunnar Seemann
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg-Bad Krozingen, Freiburg, Germany
| | - Claus Schmitt
- Medizinische Klinik IV, Städtisches Klinikum Karlsruhe, Karlsruhe, Germany
| | - Axel Loewe
- Institute of Biomedical Engineering (IBT), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
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12
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Guichard JB, Naud P, Xiong F, Qi X, L'Heureux N, Hiram R, Tardif JC, Cartier R, Da Costa A, Nattel S. Comparison of Atrial Remodeling Caused by Sustained Atrial Flutter Versus Atrial Fibrillation. J Am Coll Cardiol 2021; 76:374-388. [PMID: 32703507 DOI: 10.1016/j.jacc.2020.05.062] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 05/20/2020] [Accepted: 05/26/2020] [Indexed: 12/30/2022]
Abstract
BACKGROUND Atrial flutter (AFL) and atrial fibrillation (AF) are associated with AF-promoting atrial remodeling, but no experimental studies have addressed remodeling with sustained AFL. OBJECTIVES This study aimed to define the atrial remodeling caused by sustained atrial flutter (AFL) and/or atrial fibrillation (AF). METHODS Intercaval radiofrequency lesions created a substrate for sustained isthmus-dependent AFL, confirmed by endocavity mapping. Four groups (6 dogs per group) were followed for 3 weeks: sustained AFL; sustained AF (600 beats/min atrial tachypacing); AF superimposed on an AFL substrate (AF+AFLs); sinus rhythm (SR) with an AFL substrate (SR+AFLs; control group). All dogs had atrioventricular-node ablation and ventricular pacemakers at 80 beats/min to control ventricular rate. RESULTS Monitoring confirmed spontaneous AFL maintenance >99% of the time in dogs with AFL. At terminal open-chest study, left-atrial (LA) effective refractory period was reduced similarly with AFL, AF+AFLs and AF, while AF vulnerability to extrastimuli increased in parallel. Induced AF duration increased significantly in AF+AFLs and AF, but not AFL. Dogs with AF+AFLs had shorter cycle lengths and substantial irregularity versus dogs with AFL. LA volume increased in AF+AFLs and AF, but not dogs with AFL, versus SR+AFLs. Optical mapping showed significant conduction slowing in AF+AFLs and AF but not AFL, paralleling atrial fibrosis and collagen-gene upregulation. Left-ventricular function did not change in any group. Transcriptomic analysis revealed substantial dysregulation of inflammatory and extracellular matrix-signaling pathways with AF and AF+ALs but not AFL. CONCLUSIONS Sustained AFL causes atrial repolarization changes like those in AF but, unlike AF or AF+AFLs, does not induce structural remodeling. These results provide novel insights into AFL-induced remodeling and suggest that early intervention may be important to prevent irreversible fibrosis when AF intervenes in a patient with AFL.
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Affiliation(s)
- Jean-Baptiste Guichard
- Department of Medicine and Research Center Montreal Heart Institute and Université de Montréal, Montréal, Québec, Canada; Department of Cardiology, University Hospital of Saint-Étienne, University Jean Monnet, Saint-Étienne, France
| | - Patrice Naud
- Department of Medicine and Research Center Montreal Heart Institute and Université de Montréal, Montréal, Québec, Canada
| | - Feng Xiong
- Department of Medicine and Research Center Montreal Heart Institute and Université de Montréal, Montréal, Québec, Canada
| | - Xiaoyan Qi
- Department of Medicine and Research Center Montreal Heart Institute and Université de Montréal, Montréal, Québec, Canada
| | - Nathalie L'Heureux
- Department of Medicine and Research Center Montreal Heart Institute and Université de Montréal, Montréal, Québec, Canada
| | - Roddy Hiram
- Department of Medicine and Research Center Montreal Heart Institute and Université de Montréal, Montréal, Québec, Canada
| | - Jean-Claude Tardif
- Department of Medicine and Research Center Montreal Heart Institute and Université de Montréal, Montréal, Québec, Canada
| | - Raymond Cartier
- Department of Medicine and Research Center Montreal Heart Institute and Université de Montréal, Montréal, Québec, Canada
| | - Antoine Da Costa
- Department of Cardiology, University Hospital of Saint-Étienne, University Jean Monnet, Saint-Étienne, France
| | - Stanley Nattel
- Department of Medicine and Research Center Montreal Heart Institute and Université de Montréal, Montréal, Québec, Canada; Department of Pharmacology and Therapeutics, McGill University Montréal, Montréal, Québec, Canada; Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany; IHU LIRYC and Fondation Bordeaux Université, Bordeaux, France.
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13
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Lemoine MD, Lemme M, Ulmer BM, Braren I, Krasemann S, Hansen A, Kirchhof P, Meyer C, Eschenhagen T, Christ T. Intermittent Optogenetic Tachypacing of Atrial Engineered Heart Tissue Induces Only Limited Electrical Remodelling. J Cardiovasc Pharmacol 2020; 77:291-299. [PMID: 33278190 DOI: 10.1097/fjc.0000000000000951] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 10/13/2020] [Indexed: 01/30/2023]
Abstract
ABSTRACT Atrial tachypacing is an accepted model for atrial fibrillation (AF) in large animals and in cellular models. Human induced pluripotent stem cells-derived cardiomyocytes (hiPSC-CM) provide a novel human source to model cardiovascular diseases. Here, we investigated whether optogenetic tachypacing of atrial-like hiPSC-CMs grown into engineered heart tissue (aEHT) can induce AF-remodeling. After differentiation of atrial-like cardiomyocytes from hiPSCs using retinoic acid, aEHTs were generated from ∼1 million atrial-like hiPSC-CMs per aEHT. AEHTs were transduced with lentivirus expressing channelrhodopsin-2 to enable optogenetic stimulation by blue light pulses. AEHTs underwent optical tachypacing at 5 Hz for 15 seconds twice a minute over 3 weeks and compared with transduced spontaneously beating isogenic aEHTs (1.95 ± 0.07 Hz). Force and action potential duration did not differ between spontaneously beating and tachypaced aEHTs. Action potentials in tachypaced aEHTs showed higher upstroke velocity (138 ± 15 vs. 87 ± 11 V/s, n = 15-13/3; P = 0.018), possibly corresponding to a tendency for more negative diastolic potentials (73.0 ± 1.8 vs. 68.0 ± 1.9 mV; P = 0.07). Tachypaced aEHTs exhibited a more irregular spontaneous beating pattern (beat-to-beat scatter: 0.07 ± 0.01 vs. 0.03 ± 0.004 seconds, n = 15-13/3; P = 0.008). Targeted expression analysis showed higher RNA levels of KCNJ12 [Kir2.2, inward rectifier (IK1); 69 ± 7 vs. 44 ± 4, P = 0.014] and NPPB (NT-proBNP; 39,690 ± 4834 vs. 23,671 ± 3691; P = 0.024). Intermittent tachypacing in aEHTs induces some electrical alterations found in AF and induces an arrhythmic spontaneous beating pattern, but does not affect resting force. Further studies using longer, continuous, or more aggressive stimulation may clarify the contribution of different rate patterns on the changes in aEHT mimicking the remodeling process from paroxysmal to persistent atrial fibrillation.
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Affiliation(s)
- Marc D Lemoine
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany. Lemme is now with the Nanion Technologies GmbH, Ganghoferstraße, München, Germany
- Department of Cardiology, University Heart and Vascular Center, Hamburg, Germany
| | - Marta Lemme
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany. Lemme is now with the Nanion Technologies GmbH, Ganghoferstraße, München, Germany
| | - Bärbel M Ulmer
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany. Lemme is now with the Nanion Technologies GmbH, Ganghoferstraße, München, Germany
| | - Ingke Braren
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany. Lemme is now with the Nanion Technologies GmbH, Ganghoferstraße, München, Germany
| | - Susanne Krasemann
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Arne Hansen
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany. Lemme is now with the Nanion Technologies GmbH, Ganghoferstraße, München, Germany
| | - Paulus Kirchhof
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany. Lemme is now with the Nanion Technologies GmbH, Ganghoferstraße, München, Germany
- Department of Cardiology, University Heart and Vascular Center, Hamburg, Germany
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom; and
| | - Christian Meyer
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany. Lemme is now with the Nanion Technologies GmbH, Ganghoferstraße, München, Germany
- Department of Cardiology, University Heart and Vascular Center, Hamburg, Germany
- Clinic for Cardiology, Evangelical Hospital, Düsseldorf, Germany
| | - Thomas Eschenhagen
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany. Lemme is now with the Nanion Technologies GmbH, Ganghoferstraße, München, Germany
| | - Torsten Christ
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany. Lemme is now with the Nanion Technologies GmbH, Ganghoferstraße, München, Germany
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14
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Blomström‐Lundqvist C, Marrouche N, Connolly S, Corp dit Genti V, Wieloch M, Koren A, Hohnloser SH. Efficacy and safety of dronedarone by atrial fibrillation history duration: Insights from the ATHENA study. Clin Cardiol 2020; 43:1469-1477. [PMID: 33080088 PMCID: PMC7724236 DOI: 10.1002/clc.23463] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 08/11/2020] [Accepted: 08/24/2020] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Atrial fibrillation/atrial flutter (AF/AFL) burden increases with increasing duration of AF/AFL history. HYPOTHESIS Outcomes with dronedarone may also be impacted by duration of AF/AFL history. METHODS In this post hoc analysis of ATHENA, efficacy and safety of dronedarone vs placebo were assessed in groups categorized by time from first known AF/AFL episode to randomization (ie, duration of AF/AFL history): <3 months (short), 3 to <24 months (intermediate), and ≥ 24 months (long). RESULTS Of 2859 patients with data on duration of AF/AFL history, 45.3%, 29.6%, and 25.1% had short, intermediate, and long histories, respectively. Patients in the long history group had the highest prevalence of structural heart disease and were more likely to be in AF/AFL at baseline. Placebo-treated patients in the long history group also had the highest incidence of AF/AFL recurrence and cardiovascular (CV) hospitalization during the study. The risk of first CV hospitalization/death from any cause was lower with dronedarone vs placebo in patients with short (hazard ratio, 0.79 [95% confidence interval: 0.65-0.96]) and intermediate (0.72 [0.56-0.92]) histories; a trend favoring dronedarone was also observed in patients with long history (0.84 [0.66-1.07]). A similar pattern was observed for first AF/AFL recurrence. No new drug-related safety issues were identified. CONCLUSIONS Patients with long AF/AFL history had the highest burden of AF/AFL at baseline and during the study. Dronedarone significantly improved efficacy vs placebo in patients with short and intermediate AF/AFL histories. While exploratory, these results support the potential value in initiating rhythm control treatment early in patients with AF/AFL.
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Affiliation(s)
| | - Nassir Marrouche
- Section of CardiologyTulane University Heart and Vascular InstituteNew OrleansLouisianaUSA
| | | | | | - Mattias Wieloch
- Sanofi‐AventisParisFrance
- Department of Coagulation DisordersSkåne University Hospital, Lund UniversityMalmöSweden
| | - Andrew Koren
- SanofiBridgewaterNew Jersey, at the time of the studyUSA
| | - Stefan H. Hohnloser
- Department of CardiologyDivision of Clinical Electrophysiology, J. W. Goethe UniversityFrankfurtGermany
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15
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Ho G, Lin AY, Krummen DE. Linking Electrical Drivers With Atrial Cardiomyopathy for the Targeted Treatment of Atrial Fibrillation. Front Physiol 2020; 11:570740. [PMID: 33281614 PMCID: PMC7689158 DOI: 10.3389/fphys.2020.570740] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 09/22/2020] [Indexed: 12/19/2022] Open
Abstract
The relationship between atrial fibrillation (AF) and underlying functional and structural abnormalities has received substantial attention in the research literature over the past decade. Significant progress has been made in identifying these changes using non-invasive imaging, voltage mapping, and electrical recordings. Advances in computed tomography and cardiac magnetic resonance imaging can now provide insight regarding the presence and extent of cardiac fibrosis. Additionally, multiple technologies able to identify electrical targets during AF have emerged. However, an organized strategy to employ these resources in the targeted treatment of AF remains elusive. In this work, we will discuss the basis for mechanistic importance of atrial fibrosis and scar as potential sites promoting AF and emerging technologies to identify and target these structural and functional substrates in the electrophysiology laboratory. We also propose an approach to the use of such technologies to serve as a basis for ongoing work in the field.
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Affiliation(s)
- Gordon Ho
- Division of Cardiology, Department of Medicine, University of California, San Diego, San Diego, CA, United States
- Division of Cardiology, Veterans Affairs San Diego Medical Center, San Diego, CA, United States
| | - Andrew Y. Lin
- Division of Cardiology, Department of Medicine, University of California, San Diego, San Diego, CA, United States
- Division of Cardiology, Veterans Affairs San Diego Medical Center, San Diego, CA, United States
| | - David E. Krummen
- Division of Cardiology, Department of Medicine, University of California, San Diego, San Diego, CA, United States
- Division of Cardiology, Veterans Affairs San Diego Medical Center, San Diego, CA, United States
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16
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Mikhailov AV, Kalyanasundaram A, Li N, Scott SS, Artiga EJ, Subr MM, Zhao J, Hansen BJ, Hummel JD, Fedorov VV. Comprehensive evaluation of electrophysiological and 3D structural features of human atrial myocardium with insights on atrial fibrillation maintenance mechanisms. J Mol Cell Cardiol 2020; 151:56-71. [PMID: 33130148 DOI: 10.1016/j.yjmcc.2020.10.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 10/22/2020] [Accepted: 10/23/2020] [Indexed: 12/14/2022]
Abstract
Atrial fibrillation (AF) occurrence and maintenance is associated with progressive remodeling of electrophysiological (repolarization and conduction) and 3D structural (fibrosis, fiber orientations, and wall thickness) features of the human atria. Significant diversity in AF etiology leads to heterogeneous arrhythmogenic electrophysiological and structural substrates within the 3D structure of the human atria. Since current clinical methods have yet to fully resolve the patient-specific arrhythmogenic substrates, mechanism-based AF treatments remain underdeveloped. Here, we review current knowledge from in-vivo, ex-vivo, and in-vitro human heart studies, and discuss how these studies may provide new insights on the synergy of atrial electrophysiological and 3D structural features in AF maintenance. In-vitro studies on surgically acquired human atrial samples provide a great opportunity to study a wide spectrum of AF pathology, including functional changes in single-cell action potentials, ion channels, and gene/protein expression. However, limited size of the samples prevents evaluation of heterogeneous AF substrates and reentrant mechanisms. In contrast, coronary-perfused ex-vivo human hearts can be studied with state-of-the-art functional and structural technologies, such as high-resolution near-infrared optical mapping and contrast-enhanced MRI. These imaging modalities can resolve atrial arrhythmogenic substrates and their role in reentrant mechanisms maintaining AF and validate clinical approaches. Nonetheless, longitudinal studies are not feasible in explanted human hearts. As no approach is perfect, we suggest that combining the strengths of direct human atrial studies with high fidelity approaches available in the laboratory and in realistic patient-specific computer models would elucidate deeper knowledge of AF mechanisms. We propose that a comprehensive translational pipeline from ex-vivo human heart studies to longitudinal clinically relevant AF animal studies and finally to clinical trials is necessary to identify patient-specific arrhythmogenic substrates and develop novel AF treatments.
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Affiliation(s)
- Aleksei V Mikhailov
- Department of Physiology & Cell Biology, Bob and Corrine Frick Center for Heart Failure and Arrhythmia, The Ohio State University Wexner Medical Center, Columbus, OH, USA; Arrhythmology Research Department, Almazov National Medical Research Centre, Saint-Petersburg, Russia
| | - Anuradha Kalyanasundaram
- Department of Physiology & Cell Biology, Bob and Corrine Frick Center for Heart Failure and Arrhythmia, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Ning Li
- Department of Physiology & Cell Biology, Bob and Corrine Frick Center for Heart Failure and Arrhythmia, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Shane S Scott
- Department of Physiology & Cell Biology, Bob and Corrine Frick Center for Heart Failure and Arrhythmia, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Esthela J Artiga
- Department of Physiology & Cell Biology, Bob and Corrine Frick Center for Heart Failure and Arrhythmia, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Megan M Subr
- Department of Physiology & Cell Biology, Bob and Corrine Frick Center for Heart Failure and Arrhythmia, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Jichao Zhao
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Brian J Hansen
- Department of Physiology & Cell Biology, Bob and Corrine Frick Center for Heart Failure and Arrhythmia, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - John D Hummel
- Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA; Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Vadim V Fedorov
- Department of Physiology & Cell Biology, Bob and Corrine Frick Center for Heart Failure and Arrhythmia, The Ohio State University Wexner Medical Center, Columbus, OH, USA; Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
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17
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Hansen BJ, Zhao J, Helfrich KM, Li N, Iancau A, Zolotarev AM, Zakharkin SO, Kalyanasundaram A, Subr M, Dastagir N, Sharma R, Artiga EJ, Salgia N, Houmsse MM, Kahaly O, Janssen PML, Mohler PJ, Mokadam NA, Whitson BA, Afzal MR, Simonetti OP, Hummel JD, Fedorov VV. Unmasking Arrhythmogenic Hubs of Reentry Driving Persistent Atrial Fibrillation for Patient-Specific Treatment. J Am Heart Assoc 2020; 9:e017789. [PMID: 33006292 PMCID: PMC7792422 DOI: 10.1161/jaha.120.017789] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Background Atrial fibrillation (AF) driver mechanisms are obscured to clinical multielectrode mapping approaches that provide partial, surface‐only visualization of unstable 3‐dimensional atrial conduction. We hypothesized that transient modulation of refractoriness by pharmacologic challenge during multielectrode mapping improves visualization of hidden paths of reentrant AF drivers for targeted ablation. Methods and Results Pharmacologic challenge with adenosine was tested in ex vivo human hearts with a history of AF and cardiac diseases by multielectrode and high‐resolution subsurface near‐infrared optical mapping, integrated with 3‐dimensional structural imaging and heart‐specific computational simulations. Adenosine challenge was also studied on acutely terminated AF drivers in 10 patients with persistent AF. Ex vivo, adenosine stabilized reentrant driver paths within arrhythmogenic fibrotic hubs and improved visualization of reentrant paths, previously seen as focal or unstable breakthrough activation pattern, for targeted AF ablation. Computational simulations suggested that shortening of atrial refractoriness by adenosine may (1) improve driver stability by annihilating spatially unstable functional blocks and tightening reentrant circuits around fibrotic substrates, thus unmasking the common reentrant path; and (2) destabilize already stable reentrant drivers along fibrotic substrates by accelerating competing fibrillatory wavelets or secondary drivers. In patients with persistent AF, adenosine challenge unmasked hidden common reentry paths (9/15 AF drivers, 41±26% to 68±25% visualization), but worsened visualization of previously visible reentry paths (6/15, 74±14% to 34±12%). AF driver ablation led to acute termination of AF. Conclusions Our ex vivo to in vivo human translational study suggests that transiently altering atrial refractoriness can stabilize reentrant paths and unmask arrhythmogenic hubs to guide targeted AF driver ablation treatment.
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Affiliation(s)
- Brian J Hansen
- Department of Physiology & Cell Biology and Frick Center for Heart Failure and Arrhythmia The Ohio State University Wexner Medical Center Columbus OH.,Davis Heart & Lung Research InstituteThe Ohio State University Wexner Medical Center Columbus OH
| | | | - Katelynn M Helfrich
- Department of Physiology & Cell Biology and Frick Center for Heart Failure and Arrhythmia The Ohio State University Wexner Medical Center Columbus OH.,Davis Heart & Lung Research InstituteThe Ohio State University Wexner Medical Center Columbus OH
| | - Ning Li
- Department of Physiology & Cell Biology and Frick Center for Heart Failure and Arrhythmia The Ohio State University Wexner Medical Center Columbus OH.,Davis Heart & Lung Research InstituteThe Ohio State University Wexner Medical Center Columbus OH
| | - Alexander Iancau
- Department of Physiology & Cell Biology and Frick Center for Heart Failure and Arrhythmia The Ohio State University Wexner Medical Center Columbus OH
| | - Alexander M Zolotarev
- Department of Physiology & Cell Biology and Frick Center for Heart Failure and Arrhythmia The Ohio State University Wexner Medical Center Columbus OH.,Skolkovo Institute of Science and Technology Moscow Russia
| | - Stanislav O Zakharkin
- Department of Physiology & Cell Biology and Frick Center for Heart Failure and Arrhythmia The Ohio State University Wexner Medical Center Columbus OH
| | - Anuradha Kalyanasundaram
- Department of Physiology & Cell Biology and Frick Center for Heart Failure and Arrhythmia The Ohio State University Wexner Medical Center Columbus OH.,Davis Heart & Lung Research InstituteThe Ohio State University Wexner Medical Center Columbus OH
| | - Megan Subr
- Department of Physiology & Cell Biology and Frick Center for Heart Failure and Arrhythmia The Ohio State University Wexner Medical Center Columbus OH
| | | | | | - Esthela J Artiga
- Department of Physiology & Cell Biology and Frick Center for Heart Failure and Arrhythmia The Ohio State University Wexner Medical Center Columbus OH.,Davis Heart & Lung Research InstituteThe Ohio State University Wexner Medical Center Columbus OH
| | - Nicholas Salgia
- Department of Physiology & Cell Biology and Frick Center for Heart Failure and Arrhythmia The Ohio State University Wexner Medical Center Columbus OH
| | - Mustafa M Houmsse
- Department of Physiology & Cell Biology and Frick Center for Heart Failure and Arrhythmia The Ohio State University Wexner Medical Center Columbus OH
| | - Omar Kahaly
- Davis Heart & Lung Research InstituteThe Ohio State University Wexner Medical Center Columbus OH.,Department of Internal Medicine The Ohio State University Wexner Medical Center Columbus OH
| | - Paul M L Janssen
- Department of Physiology & Cell Biology and Frick Center for Heart Failure and Arrhythmia The Ohio State University Wexner Medical Center Columbus OH.,Davis Heart & Lung Research InstituteThe Ohio State University Wexner Medical Center Columbus OH
| | - Peter J Mohler
- Department of Physiology & Cell Biology and Frick Center for Heart Failure and Arrhythmia The Ohio State University Wexner Medical Center Columbus OH.,Davis Heart & Lung Research InstituteThe Ohio State University Wexner Medical Center Columbus OH
| | - Nahush A Mokadam
- Davis Heart & Lung Research InstituteThe Ohio State University Wexner Medical Center Columbus OH.,Division of Cardiac Surgery The Ohio State University Wexner Medical Center Columbus OH
| | - Bryan A Whitson
- Davis Heart & Lung Research InstituteThe Ohio State University Wexner Medical Center Columbus OH.,Division of Cardiac Surgery The Ohio State University Wexner Medical Center Columbus OH
| | - Muhammad R Afzal
- Davis Heart & Lung Research InstituteThe Ohio State University Wexner Medical Center Columbus OH.,Department of Internal Medicine The Ohio State University Wexner Medical Center Columbus OH
| | - Orlando P Simonetti
- Davis Heart & Lung Research InstituteThe Ohio State University Wexner Medical Center Columbus OH.,Department of Biomedical Engineering The Ohio State University Wexner Medical Center Columbus OH
| | - John D Hummel
- Davis Heart & Lung Research InstituteThe Ohio State University Wexner Medical Center Columbus OH.,Department of Internal Medicine The Ohio State University Wexner Medical Center Columbus OH
| | - Vadim V Fedorov
- Department of Physiology & Cell Biology and Frick Center for Heart Failure and Arrhythmia The Ohio State University Wexner Medical Center Columbus OH.,Davis Heart & Lung Research InstituteThe Ohio State University Wexner Medical Center Columbus OH
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18
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First-degree atrioventricular block in patients with atrial fibrillation and atrial flutter: the prevalence of intra-atrial conduction delay. J Interv Card Electrophysiol 2020; 61:421-425. [PMID: 32734408 PMCID: PMC8324594 DOI: 10.1007/s10840-020-00838-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 07/21/2020] [Indexed: 12/19/2022]
Abstract
Purpose PR interval prolongation > 200 ms resulting in the diagnosis of first-degree atrioventricular block (AVB1) is caused by a delay in the AV nodal/His conduction and/or the right intra-atrial conduction (RIAC). The aim of the study was to assess the prevalence of AVB1 due to RIAC delay (AVB1 with normal AH and HV) in patients with atrial fibrillation (AF) and atrial flutter (AFlu). Methods We included 1067 consecutive patients (33% female, age 63 ± 13 years) referred for catheter ablation of AF (AF-group) (453 patients), AF and AFlu (136 patients), AFlu (292 patients), and AVNRT/AVRT (186 patients). AH-, HV-, PR-interval, and P-wave duration were measured on the 12-lead ECG and the intracardiac electrograms in sinus rhythm. RIAC delay was defined as a prolonged PR interval > 200 ms with normal AH and HV intervals. Results The prevalence of AVB1 is higher in patients with AFlu (41%) and AF (21%) and patients with both arrhythmias (30%) as compared with a reference group (8%) of patients with AVNRT/AVRT. AVB1 was due to RIAC delay in 42 of 67 patients (63%) in the AF-group, in 37 of 96 patients (39%) in the AFlu-group, and in 17 of 36 patients (47%) in the AF/AFlu group, respectively. AV nodal conduction delay was more common in AFlu patients compared with AF patients. Conclusion RIAC delay is a common underlying cause of AVB1 in patients with AF and AFlu. These findings may impact the prescription of antiarrhythmic and AV-nodal blocking drugs. Electronic supplementary material The online version of this article (10.1007/s10840-020-00838-3) contains supplementary material, which is available to authorized users.
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19
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Yamaji H, Higashiya S, Murakami T, Hina K, Kawamura H, Murakami M, Kamikawa S, Hirohata S, Kusachi S. Efficacy of an Adjunctive Electrophysiological Test-Guided Left Atrial Posterior Wall Isolation in Persistent Atrial Fibrillation Without a Left Atrial Low-Voltage Area. Circ Arrhythm Electrophysiol 2020; 13:e008191. [PMID: 32660260 DOI: 10.1161/circep.119.008191] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Electrical remodeling precedes structural remodeling. In adjunctive left atrial (LA) low-voltage area (LVA) ablation to pulmonary vein isolation of atrial fibrillation (AF), LA areas without LVA have not been targeted for ablation. We studied the effect of adjunctive LA posterior wall isolation (PWI) on persistent AF without LA-LVA according to electrophysiological testing (EP test). METHODS We examined consecutive patients with persistent AF with (n=33) and without (n=111) LA-LVA. Patients without LA-LVA were randomly assigned to EP test-guided (n=57) and control (n=54) groups. In the EP test-guided group, an adjunctive PWI was performed in those with positive results (PWI subgroup; n=24), but not in those with negative results (n=33). The criteria for positive EP tests were an effective refractory period ≤180 ms, effective refractory period>20 ms shorter than the other sites, and/or induction of AF/atrial tachycardia (AT) during measurements. LVA ablation was performed in the patients with LA-LVA. RESULTS During the follow-up period (62±33 weeks), the EP test-guided group had significantly lower recurrence rates (19%,11/57 versus 41%, 22/54, P=0.012) and higher Kaplan-Meier AF/AT-free survival curve rates than the control group (P=0.01). No significant differences in the recurrence and AF/AT-free survival curve rates between the PWI (positive EP test) and non-PWI (negative EP test) subgroups were observed. Therefore, PWI for positive EP tests reduced the AF/AT recurrence in the EP test-guided group. A stepwise Cox proportional hazard analyses identified EP test-guided ablation as a factor reducing the recurrence rate. The recurrence rates in the LA-LVA ablation group and EP test-guided group were similar. CONCLUSIONS This pilot study proposed that an EP test-guided adjunctive PWI of persistent AF without LA-LVA potentially reduced AF/AT recurrences. The results suggest that there is an AF substrate in the LA with altered electrophysiological function even when there is no LA-LVA. Graphic Abstract: A graphic abstract is available for this article.
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Affiliation(s)
- Hirosuke Yamaji
- Heart Rhythm Center, Okayama Heart Clinic, Takeda 54-1, Naka-Ku, Japan (H.Y., S. Higashiya, T.M., K.H., H.K., M.M., S. Kamikawa, S. Kusachi)
| | - Shunichi Higashiya
- Heart Rhythm Center, Okayama Heart Clinic, Takeda 54-1, Naka-Ku, Japan (H.Y., S. Higashiya, T.M., K.H., H.K., M.M., S. Kamikawa, S. Kusachi)
| | - Takashi Murakami
- Heart Rhythm Center, Okayama Heart Clinic, Takeda 54-1, Naka-Ku, Japan (H.Y., S. Higashiya, T.M., K.H., H.K., M.M., S. Kamikawa, S. Kusachi)
| | - Kazuyoshi Hina
- Heart Rhythm Center, Okayama Heart Clinic, Takeda 54-1, Naka-Ku, Japan (H.Y., S. Higashiya, T.M., K.H., H.K., M.M., S. Kamikawa, S. Kusachi)
| | - Hiroshi Kawamura
- Heart Rhythm Center, Okayama Heart Clinic, Takeda 54-1, Naka-Ku, Japan (H.Y., S. Higashiya, T.M., K.H., H.K., M.M., S. Kamikawa, S. Kusachi)
| | - Masaaki Murakami
- Heart Rhythm Center, Okayama Heart Clinic, Takeda 54-1, Naka-Ku, Japan (H.Y., S. Higashiya, T.M., K.H., H.K., M.M., S. Kamikawa, S. Kusachi)
| | - Shigeshi Kamikawa
- Heart Rhythm Center, Okayama Heart Clinic, Takeda 54-1, Naka-Ku, Japan (H.Y., S. Higashiya, T.M., K.H., H.K., M.M., S. Kamikawa, S. Kusachi)
| | - Satoshi Hirohata
- Department of Medical Technology, Okayama University Graduate School of Health Sciences, Japan (S. Hirohata, S. Kusachi)
| | - Shozo Kusachi
- Heart Rhythm Center, Okayama Heart Clinic, Takeda 54-1, Naka-Ku, Japan (H.Y., S. Higashiya, T.M., K.H., H.K., M.M., S. Kamikawa, S. Kusachi).,Department of Medical Technology, Okayama University Graduate School of Health Sciences, Japan (S. Hirohata, S. Kusachi)
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20
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Bai J, Lu Y, Lo A, Zhao J, Zhang H. PITX2 upregulation increases the risk of chronic atrial fibrillation in a dose-dependent manner by modulating IKs and ICaL -insights from human atrial modelling. ANNALS OF TRANSLATIONAL MEDICINE 2020; 8:191. [PMID: 32309338 PMCID: PMC7154416 DOI: 10.21037/atm.2020.01.90] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Background Functional analysis has shown that the paired-like homeodomain transcription factor 2 (PITX2) overexpression associated with atrial fibrillation (AF) leads to the slow delayed rectifier K+ current (IKs) increase and the L-type Ca2+ current (ICaL) reduction observed in isolated right atrial myocytes from chronic AF (CAF) patients. Through multiscale computational models, this study aimed to investigate the functional impact of the PITX2 overexpression on atrial electrical activity. Methods The well-known Courtemanche-Ramirez-Nattel (CRN) model of human atrial action potentials (APs) was updated to incorporate experimental data on alterations in IKs and ICaL due to the PITX2 overexpression. These cell models for sinus rhythm (SR) and CAF were then incorporated into homogeneous multicellular one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) tissue models. The proarrhythmic effects of the PITX2 overexpression were quantified with ion current profiles, AP morphology, AP duration (APD) restitution, conduction velocity restitution (CVR), wavelength (WL), vulnerable window (VW) for unidirectional conduction block, and minimal substrate size required to induce re-entry. Dynamic behaviors of spiral waves were characterized by measuring lifespan (LS), tip patterns and dominant frequencies. Results The IKs increase and the ICaL decrease arising from the PITX2 overexpression abbreviated APD and flattened APD restitution (APDR) curves in single cells. It reduced WL and increased CV at high excitation rates at the 1D tissue level. Although it had no effects on VW for initiating spiral waves, it decreased the minimal substrate size necessary to sustain re-entry. It also stabilized and accelerated spiral waves in 2D and 3D tissue models. Conclusions Electrical remodeling (IKs and ICaL) due to the PITX2 overexpression increases susceptibility to AF due to increased tissue vulnerability, abbreviated APD, shortened WL and altered CV, which, in combination, facilitate initiation and maintenance of spiral waves.
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Affiliation(s)
- Jieyun Bai
- Department of Electronic Engineering, College of Information Science and Technology, Jinan University, Guangzhou 510632, China
| | - Yaosheng Lu
- Department of Electronic Engineering, College of Information Science and Technology, Jinan University, Guangzhou 510632, China
| | - Andy Lo
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Jichao Zhao
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Henggui Zhang
- Biological Physics Group, School of Physics & Astronomy, University of Manchester, Manchester, UK
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21
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Park YM, Lee DI, Park HC, Shim J, Choi J, Park SW, Kim Y. The extent of complex fractionated atrial electrograms in the left atrium reflects age-related electrical remodeling in patients with persistent atrial fibrillation. J Arrhythm 2019; 35:805-812. [PMID: 31844470 PMCID: PMC6898536 DOI: 10.1002/joa3.12248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 08/13/2019] [Accepted: 09/11/2019] [Indexed: 11/09/2022] Open
Abstract
BACKGROUNDS Alterations in the atrial structure and function associated with aging result in electric remodeling of the left atrium (LA) in patients with persistent atrial fibrillation (AF). We performed this study to evaluate the influence of age on electric remodeling as assessed by the extent of complex fractionated atrial electrograms (CFAEs) in the LA. METHODS A total of 122 patients (mean age, 55.9 ± 10.4 years; range, 31-79; 106 males) who underwent catheter ablation for drug-refractory persistent AF were included in the study. The extent of CFAE was measured by CFAE area and its index (CFAE area/LA surface area × 100) using three-dimensional automated software of NavX system. RESULTS The mean value of CFAE extent was significantly different among age groups; the CFAE area decreased significantly with increasing age (30 seconds [43.2 ± 14.5 mm2] vs 40 seconds [28.6 ± 6.0 mm2] vs 50 seconds [22.8 ± 3.4 mm2] vs 60 seconds [15.3 ± 2.6 mm2] vs 70 seconds [10.3 ± 3.2 mm2]; P = .010). A similar significant decrease was observed in the CFAE area index (30 seconds [22.9 ± 7.4] vs 40 seconds [14.9 ± 3.4] vs 50 seconds [10.4 ± 1.6] vs 60 seconds [6.9 ± 1.2] vs 70 seconds [4.6 ± 1.4]; P = .002). Age had a significantly negative correlation with the CFAE area (r = -0.322, P < .001) and CFAE area index (r = -0.357, P < .001). CONCLUSIONS Increasing age is associated with electric remodeling in the LA characterized by a decrease in the extent of CFAE area and its index.
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Affiliation(s)
- Yae Min Park
- Cardiology DivisionGachon University Gil Medical CenterIncheonKorea
| | - Dae In Lee
- Cardiology DivisionKorea University Anam HospitalSeoulKorea
| | - Hwan Cheol Park
- Cardiology DivisionHanyang University Guri HospitalGuriKorea
| | - Jaemin Shim
- Cardiology DivisionKorea University Anam HospitalSeoulKorea
| | - Jong‐Il Choi
- Cardiology DivisionKorea University Anam HospitalSeoulKorea
| | | | - Young‐Hoon Kim
- Cardiology DivisionKorea University Anam HospitalSeoulKorea
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22
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Ramirez RJ, Takemoto Y, Martins RP, Filgueiras-Rama D, Ennis SR, Mironov S, Bhushal S, Deo M, Rajamani S, Berenfeld O, Belardinelli L, Jalife J, Pandit SV. Mechanisms by Which Ranolazine Terminates Paroxysmal but Not Persistent Atrial Fibrillation. Circ Arrhythm Electrophysiol 2019; 12:e005557. [PMID: 31594392 DOI: 10.1161/circep.117.005557] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND Ranolazine inhibits Na+ current (INa), but whether it can convert atrial fibrillation (AF) to sinus rhythm remains unclear. We investigated antiarrhythmic mechanisms of ranolazine in sheep models of paroxysmal (PxAF) and persistent AF (PsAF). METHODS PxAF was maintained during acute stretch (N=8), and PsAF was induced by long-term atrial tachypacing (N=9). Isolated, Langendorff-perfused sheep hearts were optically mapped. RESULTS In PxAF ranolazine (10 μmol/L) reduced dominant frequency from 8.3±0.4 to 6.2±0.5 Hz (P<0.01) before converting to sinus rhythm, decreased singularity point density from 0.070±0.007 to 0.039±0.005 cm-2 s-1 (P<0.001) in left atrial epicardium (LAepi), and prolonged AF cycle length (AFCL); rotor duration, tip trajectory, and variance of AFCL were unaltered. In PsAF, ranolazine reduced dominant frequency (8.3±0.5 to 6.5±0.4 Hz; P<0.01), prolonged AFCL, increased the variance of AFCL, had no effect on singularity point density (0.048±0.011 to 0.042±0.016 cm-2 s-1; P=ns) and failed to convert AF to sinus rhythm. Doubling the ranolazine concentration (20 μmol/L) or supplementing with dofetilide (1 μmol/L) failed to convert PsAF to sinus rhythm. In computer simulations of rotors, reducing INa decreased dominant frequency, increased tip meandering and produced vortex shedding on wave interaction with unexcitable regions. CONCLUSIONS PxAF and PsAF respond differently to ranolazine. Cardioversion in the former can be attributed partly to decreased dominant frequency and singularity point density, and prolongation of AFCL. In the latter, increased dispersion of AFCL and likely vortex shedding contributes to rotor formation, compensating for any rotor loss, and may underlie the inefficacy of ranolazine to terminate PsAF.
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Affiliation(s)
- Rafael J Ramirez
- Center for Arrhythmia Research, Department of Internal Medicine-Cardiology, University of Michigan, Ann Arbor (R.J.R., Y.T., R.P.M., D.F.-R., S.R.E., S.M., O.B., J.J., S.V.P.)
| | - Yoshio Takemoto
- Center for Arrhythmia Research, Department of Internal Medicine-Cardiology, University of Michigan, Ann Arbor (R.J.R., Y.T., R.P.M., D.F.-R., S.R.E., S.M., O.B., J.J., S.V.P.)
| | - Raphaël P Martins
- Center for Arrhythmia Research, Department of Internal Medicine-Cardiology, University of Michigan, Ann Arbor (R.J.R., Y.T., R.P.M., D.F.-R., S.R.E., S.M., O.B., J.J., S.V.P.)
| | - David Filgueiras-Rama
- Center for Arrhythmia Research, Department of Internal Medicine-Cardiology, University of Michigan, Ann Arbor (R.J.R., Y.T., R.P.M., D.F.-R., S.R.E., S.M., O.B., J.J., S.V.P.).,Fundación Centro Nacional de Investigaciones Cardiovasculares, Carlos III (CNIC; D.F.-R., J.J.).,Centros de Investigación Biomédica en Red (CIBER) for Cardiovascular Diseases, Madrid, Spain (D.F.-R., J.J.)
| | - Steven R Ennis
- Center for Arrhythmia Research, Department of Internal Medicine-Cardiology, University of Michigan, Ann Arbor (R.J.R., Y.T., R.P.M., D.F.-R., S.R.E., S.M., O.B., J.J., S.V.P.)
| | - Sergey Mironov
- Center for Arrhythmia Research, Department of Internal Medicine-Cardiology, University of Michigan, Ann Arbor (R.J.R., Y.T., R.P.M., D.F.-R., S.R.E., S.M., O.B., J.J., S.V.P.)
| | - Sandesh Bhushal
- Department of Engineering, Norfolk State University, VA (S.B., M.D.)
| | - Makarand Deo
- Department of Engineering, Norfolk State University, VA (S.B., M.D.)
| | - Sridharan Rajamani
- Gilead Sciences, Foster City, CA (S.R., L.B.).,Currently: Amgen Inc, San Francisco, CA (S.R.)
| | - Omer Berenfeld
- Center for Arrhythmia Research, Department of Internal Medicine-Cardiology, University of Michigan, Ann Arbor (R.J.R., Y.T., R.P.M., D.F.-R., S.R.E., S.M., O.B., J.J., S.V.P.)
| | | | - José Jalife
- Center for Arrhythmia Research, Department of Internal Medicine-Cardiology, University of Michigan, Ann Arbor (R.J.R., Y.T., R.P.M., D.F.-R., S.R.E., S.M., O.B., J.J., S.V.P.).,Fundación Centro Nacional de Investigaciones Cardiovasculares, Carlos III (CNIC; D.F.-R., J.J.).,Centros de Investigación Biomédica en Red (CIBER) for Cardiovascular Diseases, Madrid, Spain (D.F.-R., J.J.)
| | - Sandeep V Pandit
- Center for Arrhythmia Research, Department of Internal Medicine-Cardiology, University of Michigan, Ann Arbor (R.J.R., Y.T., R.P.M., D.F.-R., S.R.E., S.M., O.B., J.J., S.V.P.)
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23
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Alzahrani T, McCaffrey J, Mercader M, Solomon A. Rate Versus Rhythm Control in Patients with Normal to Mild Left Atrial Enlargement: Insights from the AFFIRM Trial. J Atr Fibrillation 2019; 11:2067. [PMID: 31139272 DOI: 10.4022/jafib.2067] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Revised: 08/19/2017] [Accepted: 09/14/2017] [Indexed: 12/19/2022]
Abstract
Background Atrial fibrillation is the most commonly encountered sustained arrhythmia and is associated with significant morbidity and mortality. Several trials have demonstrated that no mortality benefit exists when choosing a rhythm-control strategy over a rate-control strategy, with some trials suggesting an increase in mortality. Using the AFFIRM trial database we sought to determine the effect of rhythm control strategy in patients with normal or mild atrial enlargement. Methods AFFIRM Trial database was used to evaluate the effect of rhythm-control strategy compared to rate-control strategy in a subgroup of patients with normal to mild left atrial (LA) enlargement. The primary outcome measures of this study were all-cause mortality, cardiovascular mortality, non-cardiovascular mortality, and hospitalization/ED visit. Results We identified a subgroup of subjects from the AFFIRM trial with normal or mild LA enlargement (n=2022 of 4060 total subjects). Subjects in the rhythm-control group(n= 1022) had an increased risk of all-cause mortality by 34% (RR 1.34, 95% CI 1.08-1.67; P=0.007) and hospitalization/ED visits by 10% (RR 1.10, 95% CI 1.05-2.16; P=<0.001) compared to rate control group(n= 1000). Conclusion This study demonstrated that rhythm-control strategy increases the risk of mortality and hospitalization in a subgroup of patients with normal to mild atrial enlargement compared to rate-control strategy. Amiodarone use in this subgroup of patients likely drove these findings.
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Affiliation(s)
- Talal Alzahrani
- Division of Cardiology, Department of Medicine, George Washington University, Washington, DC
| | - James McCaffrey
- Division of Cardiology, Department of Medicine, George Washington University, Washington, DC
| | - Marco Mercader
- Division of Cardiology, Department of Medicine, George Washington University, Washington, DC
| | - Allen Solomon
- Division of Cardiology, Department of Medicine, George Washington University, Washington, DC
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24
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Ni H, Zhang H, Grandi E, Narayan SM, Giles WR. Transient outward K + current can strongly modulate action potential duration and initiate alternans in the human atrium. Am J Physiol Heart Circ Physiol 2019; 316:H527-H542. [PMID: 30576220 PMCID: PMC6415821 DOI: 10.1152/ajpheart.00251.2018] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 07/27/2018] [Accepted: 08/15/2018] [Indexed: 01/14/2023]
Abstract
Efforts to identify the mechanisms for the initiation and maintenance of human atrial fibrillation (AF) often focus on changes in specific elements of the atrial "substrate," i.e., its electrophysiological properties and/or structural components. We used experimentally validated mathematical models of the human atrial myocyte action potential (AP), both at baseline in sinus rhythm (SR) and in the setting of chronic AF, to identify significant contributions of the Ca2+-independent transient outward K+ current ( Ito) to electrophysiological instability and arrhythmia initiation. First, we explored whether changes in the recovery or restitution of the AP duration (APD) and/or its dynamic stability (alternans) can be modulated by Ito. Recent reports have identified disease-dependent spatial differences in expression levels of the specific K+ channel α-subunits that underlie Ito in the left atrium. Therefore, we studied the functional consequences of this by deletion of 50% of native Ito (Kv4.3) and its replacement with Kv1.4. Interestingly, significant changes in the short-term stability of the human atrial AP waveform were revealed. Specifically, this K+ channel isoform switch produced discontinuities in the initial slope of the APD restitution curve and appearance of APD alternans. This pattern of in silico results resembles some of the changes observed in high-resolution clinical electrophysiological recordings. Important insights into mechanisms for these changes emerged from known biophysical properties (reactivation kinetics) of Kv1.4 versus those of Kv4.3. These results suggest new approaches for pharmacological management of AF, based on molecular properties of specific K+ isoforms and their changed expression during progressive disease. NEW & NOTEWORTHY Clinical studies identify oscillations (alternans) in action potential (AP) duration as a predictor for atrial fibrillation (AF). The abbreviated AP in AF also involves changes in K+ currents and early repolarization of the AP. Our simulations illustrate how substitution of Kv1.4 for the native current, Kv4.3, alters the AP waveform and enhances alternans. Knowledge of this "isoform switch" and related dynamics in the AF substrate may guide new approaches for detection and management of AF.
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Affiliation(s)
- Haibo Ni
- Biological Physics Group, School of Physics and Astronomy, University of Manchester , Manchester , United Kingdom
- Department of Pharmacology, University of California , Davis, California
| | - Henggui Zhang
- Biological Physics Group, School of Physics and Astronomy, University of Manchester , Manchester , United Kingdom
| | - Eleonora Grandi
- Department of Pharmacology, University of California , Davis, California
| | - Sanjiv M Narayan
- Division of Cardiology, Cardiovascular Institute, Stanford University , Stanford, California
| | - Wayne R Giles
- Faculties of Kinesiology and Medicine, University of Calgary , Calgary, Alberta , Canada
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Pulit SL, Weng LC, McArdle PF, Trinquart L, Choi SH, Mitchell BD, Rosand J, de Bakker PIW, Benjamin EJ, Ellinor PT, Kittner SJ, Lubitz SA, Anderson CD. Atrial fibrillation genetic risk differentiates cardioembolic stroke from other stroke subtypes. Neurol Genet 2018; 4:e293. [PMID: 30584597 PMCID: PMC6283455 DOI: 10.1212/nxg.0000000000000293] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2018] [Accepted: 09/09/2018] [Indexed: 12/24/2022]
Abstract
OBJECTIVE We sought to assess whether genetic risk factors for atrial fibrillation (AF) can explain cardioembolic stroke risk. METHODS We evaluated genetic correlations between a previous genetic study of AF and AF in the presence of cardioembolic stroke using genome-wide genotypes from the Stroke Genetics Network (N = 3,190 AF cases, 3,000 cardioembolic stroke cases, and 28,026 referents). We tested whether a previously validated AF polygenic risk score (PRS) associated with cardioembolic and other stroke subtypes after accounting for AF clinical risk factors. RESULTS We observed a strong correlation between previously reported genetic risk for AF, AF in the presence of stroke, and cardioembolic stroke (Pearson r = 0.77 and 0.76, respectively, across SNPs with p < 4.4 × 10-4 in the previous AF meta-analysis). An AF PRS, adjusted for clinical AF risk factors, was associated with cardioembolic stroke (odds ratio [OR] per SD = 1.40, p = 1.45 × 10-48), explaining ∼20% of the heritable component of cardioembolic stroke risk. The AF PRS was also associated with stroke of undetermined cause (OR per SD = 1.07, p = 0.004), but no other primary stroke subtypes (all p > 0.1). CONCLUSIONS Genetic risk of AF is associated with cardioembolic stroke, independent of clinical risk factors. Studies are warranted to determine whether AF genetic risk can serve as a biomarker for strokes caused by AF.
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Affiliation(s)
- Sara L Pulit
- Department of Genetics (S.L.P., P.I.W.d. B.), University Medical Center Utrecht, Utrecht University, The Netherlands; P.I.W.d.B. is now with Computational Genomics, Vertex Pharmaceuticals, Boston, MA; Li Ka Shing Centre for Health Information and Discovery (S.L.P.), The Big Data Institute, University of Oxford, United Kingdom; Program in Medical and Population Genetics (S.L.P., L.-C.W., S.H.C., J.R., P.T.E., S.A.L., C.D.A.), Broad Institute, Cambridge, MA; Cardiovascular Research Center (L.-C.W., P.T.E., S.A.L.), Center for Genomic Medicine (J.R., C.D.A.), J.P. Kistler Stroke Research Center (J.R., C.D.A.), and Cardiac Arrhythmia Service (P.T.E., S.A.L.), Massachusetts General Hospital, Boston; Department of Medicine (P.F.M., B.D.M.), Program for Personalized and Genomic Medicine, University of Maryland School of Medicine, Baltimore; National Heart, Lung, and Blood Institute's and Boston University's Framingham Heart Study (L.T., E.J.B.); Department of Biostatistics (L.T.) and Department of Epidemiology (E.J.B.), Boston University School of Public Health, MA; Geriatrics Research and Education Clinical Center (B.D.M.), Baltimore Veterans Administration Medical Center, MD; Cardiology Preventive Medicine Sections (E.J.B.), Evans Department of Medicine, Boston University School of Medicine; Department of Neurology (S.J.K.), University of Maryland School of Medicine; and Department of Neurology (S.J.K.), Veterans Affairs Medical Center, Baltimore, MD
| | - Lu-Chen Weng
- Department of Genetics (S.L.P., P.I.W.d. B.), University Medical Center Utrecht, Utrecht University, The Netherlands; P.I.W.d.B. is now with Computational Genomics, Vertex Pharmaceuticals, Boston, MA; Li Ka Shing Centre for Health Information and Discovery (S.L.P.), The Big Data Institute, University of Oxford, United Kingdom; Program in Medical and Population Genetics (S.L.P., L.-C.W., S.H.C., J.R., P.T.E., S.A.L., C.D.A.), Broad Institute, Cambridge, MA; Cardiovascular Research Center (L.-C.W., P.T.E., S.A.L.), Center for Genomic Medicine (J.R., C.D.A.), J.P. Kistler Stroke Research Center (J.R., C.D.A.), and Cardiac Arrhythmia Service (P.T.E., S.A.L.), Massachusetts General Hospital, Boston; Department of Medicine (P.F.M., B.D.M.), Program for Personalized and Genomic Medicine, University of Maryland School of Medicine, Baltimore; National Heart, Lung, and Blood Institute's and Boston University's Framingham Heart Study (L.T., E.J.B.); Department of Biostatistics (L.T.) and Department of Epidemiology (E.J.B.), Boston University School of Public Health, MA; Geriatrics Research and Education Clinical Center (B.D.M.), Baltimore Veterans Administration Medical Center, MD; Cardiology Preventive Medicine Sections (E.J.B.), Evans Department of Medicine, Boston University School of Medicine; Department of Neurology (S.J.K.), University of Maryland School of Medicine; and Department of Neurology (S.J.K.), Veterans Affairs Medical Center, Baltimore, MD
| | - Patrick F McArdle
- Department of Genetics (S.L.P., P.I.W.d. B.), University Medical Center Utrecht, Utrecht University, The Netherlands; P.I.W.d.B. is now with Computational Genomics, Vertex Pharmaceuticals, Boston, MA; Li Ka Shing Centre for Health Information and Discovery (S.L.P.), The Big Data Institute, University of Oxford, United Kingdom; Program in Medical and Population Genetics (S.L.P., L.-C.W., S.H.C., J.R., P.T.E., S.A.L., C.D.A.), Broad Institute, Cambridge, MA; Cardiovascular Research Center (L.-C.W., P.T.E., S.A.L.), Center for Genomic Medicine (J.R., C.D.A.), J.P. Kistler Stroke Research Center (J.R., C.D.A.), and Cardiac Arrhythmia Service (P.T.E., S.A.L.), Massachusetts General Hospital, Boston; Department of Medicine (P.F.M., B.D.M.), Program for Personalized and Genomic Medicine, University of Maryland School of Medicine, Baltimore; National Heart, Lung, and Blood Institute's and Boston University's Framingham Heart Study (L.T., E.J.B.); Department of Biostatistics (L.T.) and Department of Epidemiology (E.J.B.), Boston University School of Public Health, MA; Geriatrics Research and Education Clinical Center (B.D.M.), Baltimore Veterans Administration Medical Center, MD; Cardiology Preventive Medicine Sections (E.J.B.), Evans Department of Medicine, Boston University School of Medicine; Department of Neurology (S.J.K.), University of Maryland School of Medicine; and Department of Neurology (S.J.K.), Veterans Affairs Medical Center, Baltimore, MD
| | - Ludovic Trinquart
- Department of Genetics (S.L.P., P.I.W.d. B.), University Medical Center Utrecht, Utrecht University, The Netherlands; P.I.W.d.B. is now with Computational Genomics, Vertex Pharmaceuticals, Boston, MA; Li Ka Shing Centre for Health Information and Discovery (S.L.P.), The Big Data Institute, University of Oxford, United Kingdom; Program in Medical and Population Genetics (S.L.P., L.-C.W., S.H.C., J.R., P.T.E., S.A.L., C.D.A.), Broad Institute, Cambridge, MA; Cardiovascular Research Center (L.-C.W., P.T.E., S.A.L.), Center for Genomic Medicine (J.R., C.D.A.), J.P. Kistler Stroke Research Center (J.R., C.D.A.), and Cardiac Arrhythmia Service (P.T.E., S.A.L.), Massachusetts General Hospital, Boston; Department of Medicine (P.F.M., B.D.M.), Program for Personalized and Genomic Medicine, University of Maryland School of Medicine, Baltimore; National Heart, Lung, and Blood Institute's and Boston University's Framingham Heart Study (L.T., E.J.B.); Department of Biostatistics (L.T.) and Department of Epidemiology (E.J.B.), Boston University School of Public Health, MA; Geriatrics Research and Education Clinical Center (B.D.M.), Baltimore Veterans Administration Medical Center, MD; Cardiology Preventive Medicine Sections (E.J.B.), Evans Department of Medicine, Boston University School of Medicine; Department of Neurology (S.J.K.), University of Maryland School of Medicine; and Department of Neurology (S.J.K.), Veterans Affairs Medical Center, Baltimore, MD
| | - Seung Hoan Choi
- Department of Genetics (S.L.P., P.I.W.d. B.), University Medical Center Utrecht, Utrecht University, The Netherlands; P.I.W.d.B. is now with Computational Genomics, Vertex Pharmaceuticals, Boston, MA; Li Ka Shing Centre for Health Information and Discovery (S.L.P.), The Big Data Institute, University of Oxford, United Kingdom; Program in Medical and Population Genetics (S.L.P., L.-C.W., S.H.C., J.R., P.T.E., S.A.L., C.D.A.), Broad Institute, Cambridge, MA; Cardiovascular Research Center (L.-C.W., P.T.E., S.A.L.), Center for Genomic Medicine (J.R., C.D.A.), J.P. Kistler Stroke Research Center (J.R., C.D.A.), and Cardiac Arrhythmia Service (P.T.E., S.A.L.), Massachusetts General Hospital, Boston; Department of Medicine (P.F.M., B.D.M.), Program for Personalized and Genomic Medicine, University of Maryland School of Medicine, Baltimore; National Heart, Lung, and Blood Institute's and Boston University's Framingham Heart Study (L.T., E.J.B.); Department of Biostatistics (L.T.) and Department of Epidemiology (E.J.B.), Boston University School of Public Health, MA; Geriatrics Research and Education Clinical Center (B.D.M.), Baltimore Veterans Administration Medical Center, MD; Cardiology Preventive Medicine Sections (E.J.B.), Evans Department of Medicine, Boston University School of Medicine; Department of Neurology (S.J.K.), University of Maryland School of Medicine; and Department of Neurology (S.J.K.), Veterans Affairs Medical Center, Baltimore, MD
| | - Braxton D Mitchell
- Department of Genetics (S.L.P., P.I.W.d. B.), University Medical Center Utrecht, Utrecht University, The Netherlands; P.I.W.d.B. is now with Computational Genomics, Vertex Pharmaceuticals, Boston, MA; Li Ka Shing Centre for Health Information and Discovery (S.L.P.), The Big Data Institute, University of Oxford, United Kingdom; Program in Medical and Population Genetics (S.L.P., L.-C.W., S.H.C., J.R., P.T.E., S.A.L., C.D.A.), Broad Institute, Cambridge, MA; Cardiovascular Research Center (L.-C.W., P.T.E., S.A.L.), Center for Genomic Medicine (J.R., C.D.A.), J.P. Kistler Stroke Research Center (J.R., C.D.A.), and Cardiac Arrhythmia Service (P.T.E., S.A.L.), Massachusetts General Hospital, Boston; Department of Medicine (P.F.M., B.D.M.), Program for Personalized and Genomic Medicine, University of Maryland School of Medicine, Baltimore; National Heart, Lung, and Blood Institute's and Boston University's Framingham Heart Study (L.T., E.J.B.); Department of Biostatistics (L.T.) and Department of Epidemiology (E.J.B.), Boston University School of Public Health, MA; Geriatrics Research and Education Clinical Center (B.D.M.), Baltimore Veterans Administration Medical Center, MD; Cardiology Preventive Medicine Sections (E.J.B.), Evans Department of Medicine, Boston University School of Medicine; Department of Neurology (S.J.K.), University of Maryland School of Medicine; and Department of Neurology (S.J.K.), Veterans Affairs Medical Center, Baltimore, MD
| | - Jonathan Rosand
- Department of Genetics (S.L.P., P.I.W.d. B.), University Medical Center Utrecht, Utrecht University, The Netherlands; P.I.W.d.B. is now with Computational Genomics, Vertex Pharmaceuticals, Boston, MA; Li Ka Shing Centre for Health Information and Discovery (S.L.P.), The Big Data Institute, University of Oxford, United Kingdom; Program in Medical and Population Genetics (S.L.P., L.-C.W., S.H.C., J.R., P.T.E., S.A.L., C.D.A.), Broad Institute, Cambridge, MA; Cardiovascular Research Center (L.-C.W., P.T.E., S.A.L.), Center for Genomic Medicine (J.R., C.D.A.), J.P. Kistler Stroke Research Center (J.R., C.D.A.), and Cardiac Arrhythmia Service (P.T.E., S.A.L.), Massachusetts General Hospital, Boston; Department of Medicine (P.F.M., B.D.M.), Program for Personalized and Genomic Medicine, University of Maryland School of Medicine, Baltimore; National Heart, Lung, and Blood Institute's and Boston University's Framingham Heart Study (L.T., E.J.B.); Department of Biostatistics (L.T.) and Department of Epidemiology (E.J.B.), Boston University School of Public Health, MA; Geriatrics Research and Education Clinical Center (B.D.M.), Baltimore Veterans Administration Medical Center, MD; Cardiology Preventive Medicine Sections (E.J.B.), Evans Department of Medicine, Boston University School of Medicine; Department of Neurology (S.J.K.), University of Maryland School of Medicine; and Department of Neurology (S.J.K.), Veterans Affairs Medical Center, Baltimore, MD
| | - Paul I W de Bakker
- Department of Genetics (S.L.P., P.I.W.d. B.), University Medical Center Utrecht, Utrecht University, The Netherlands; P.I.W.d.B. is now with Computational Genomics, Vertex Pharmaceuticals, Boston, MA; Li Ka Shing Centre for Health Information and Discovery (S.L.P.), The Big Data Institute, University of Oxford, United Kingdom; Program in Medical and Population Genetics (S.L.P., L.-C.W., S.H.C., J.R., P.T.E., S.A.L., C.D.A.), Broad Institute, Cambridge, MA; Cardiovascular Research Center (L.-C.W., P.T.E., S.A.L.), Center for Genomic Medicine (J.R., C.D.A.), J.P. Kistler Stroke Research Center (J.R., C.D.A.), and Cardiac Arrhythmia Service (P.T.E., S.A.L.), Massachusetts General Hospital, Boston; Department of Medicine (P.F.M., B.D.M.), Program for Personalized and Genomic Medicine, University of Maryland School of Medicine, Baltimore; National Heart, Lung, and Blood Institute's and Boston University's Framingham Heart Study (L.T., E.J.B.); Department of Biostatistics (L.T.) and Department of Epidemiology (E.J.B.), Boston University School of Public Health, MA; Geriatrics Research and Education Clinical Center (B.D.M.), Baltimore Veterans Administration Medical Center, MD; Cardiology Preventive Medicine Sections (E.J.B.), Evans Department of Medicine, Boston University School of Medicine; Department of Neurology (S.J.K.), University of Maryland School of Medicine; and Department of Neurology (S.J.K.), Veterans Affairs Medical Center, Baltimore, MD
| | - Emelia J Benjamin
- Department of Genetics (S.L.P., P.I.W.d. B.), University Medical Center Utrecht, Utrecht University, The Netherlands; P.I.W.d.B. is now with Computational Genomics, Vertex Pharmaceuticals, Boston, MA; Li Ka Shing Centre for Health Information and Discovery (S.L.P.), The Big Data Institute, University of Oxford, United Kingdom; Program in Medical and Population Genetics (S.L.P., L.-C.W., S.H.C., J.R., P.T.E., S.A.L., C.D.A.), Broad Institute, Cambridge, MA; Cardiovascular Research Center (L.-C.W., P.T.E., S.A.L.), Center for Genomic Medicine (J.R., C.D.A.), J.P. Kistler Stroke Research Center (J.R., C.D.A.), and Cardiac Arrhythmia Service (P.T.E., S.A.L.), Massachusetts General Hospital, Boston; Department of Medicine (P.F.M., B.D.M.), Program for Personalized and Genomic Medicine, University of Maryland School of Medicine, Baltimore; National Heart, Lung, and Blood Institute's and Boston University's Framingham Heart Study (L.T., E.J.B.); Department of Biostatistics (L.T.) and Department of Epidemiology (E.J.B.), Boston University School of Public Health, MA; Geriatrics Research and Education Clinical Center (B.D.M.), Baltimore Veterans Administration Medical Center, MD; Cardiology Preventive Medicine Sections (E.J.B.), Evans Department of Medicine, Boston University School of Medicine; Department of Neurology (S.J.K.), University of Maryland School of Medicine; and Department of Neurology (S.J.K.), Veterans Affairs Medical Center, Baltimore, MD
| | - Patrick T Ellinor
- Department of Genetics (S.L.P., P.I.W.d. B.), University Medical Center Utrecht, Utrecht University, The Netherlands; P.I.W.d.B. is now with Computational Genomics, Vertex Pharmaceuticals, Boston, MA; Li Ka Shing Centre for Health Information and Discovery (S.L.P.), The Big Data Institute, University of Oxford, United Kingdom; Program in Medical and Population Genetics (S.L.P., L.-C.W., S.H.C., J.R., P.T.E., S.A.L., C.D.A.), Broad Institute, Cambridge, MA; Cardiovascular Research Center (L.-C.W., P.T.E., S.A.L.), Center for Genomic Medicine (J.R., C.D.A.), J.P. Kistler Stroke Research Center (J.R., C.D.A.), and Cardiac Arrhythmia Service (P.T.E., S.A.L.), Massachusetts General Hospital, Boston; Department of Medicine (P.F.M., B.D.M.), Program for Personalized and Genomic Medicine, University of Maryland School of Medicine, Baltimore; National Heart, Lung, and Blood Institute's and Boston University's Framingham Heart Study (L.T., E.J.B.); Department of Biostatistics (L.T.) and Department of Epidemiology (E.J.B.), Boston University School of Public Health, MA; Geriatrics Research and Education Clinical Center (B.D.M.), Baltimore Veterans Administration Medical Center, MD; Cardiology Preventive Medicine Sections (E.J.B.), Evans Department of Medicine, Boston University School of Medicine; Department of Neurology (S.J.K.), University of Maryland School of Medicine; and Department of Neurology (S.J.K.), Veterans Affairs Medical Center, Baltimore, MD
| | - Steven J Kittner
- Department of Genetics (S.L.P., P.I.W.d. B.), University Medical Center Utrecht, Utrecht University, The Netherlands; P.I.W.d.B. is now with Computational Genomics, Vertex Pharmaceuticals, Boston, MA; Li Ka Shing Centre for Health Information and Discovery (S.L.P.), The Big Data Institute, University of Oxford, United Kingdom; Program in Medical and Population Genetics (S.L.P., L.-C.W., S.H.C., J.R., P.T.E., S.A.L., C.D.A.), Broad Institute, Cambridge, MA; Cardiovascular Research Center (L.-C.W., P.T.E., S.A.L.), Center for Genomic Medicine (J.R., C.D.A.), J.P. Kistler Stroke Research Center (J.R., C.D.A.), and Cardiac Arrhythmia Service (P.T.E., S.A.L.), Massachusetts General Hospital, Boston; Department of Medicine (P.F.M., B.D.M.), Program for Personalized and Genomic Medicine, University of Maryland School of Medicine, Baltimore; National Heart, Lung, and Blood Institute's and Boston University's Framingham Heart Study (L.T., E.J.B.); Department of Biostatistics (L.T.) and Department of Epidemiology (E.J.B.), Boston University School of Public Health, MA; Geriatrics Research and Education Clinical Center (B.D.M.), Baltimore Veterans Administration Medical Center, MD; Cardiology Preventive Medicine Sections (E.J.B.), Evans Department of Medicine, Boston University School of Medicine; Department of Neurology (S.J.K.), University of Maryland School of Medicine; and Department of Neurology (S.J.K.), Veterans Affairs Medical Center, Baltimore, MD
| | - Steven A Lubitz
- Department of Genetics (S.L.P., P.I.W.d. B.), University Medical Center Utrecht, Utrecht University, The Netherlands; P.I.W.d.B. is now with Computational Genomics, Vertex Pharmaceuticals, Boston, MA; Li Ka Shing Centre for Health Information and Discovery (S.L.P.), The Big Data Institute, University of Oxford, United Kingdom; Program in Medical and Population Genetics (S.L.P., L.-C.W., S.H.C., J.R., P.T.E., S.A.L., C.D.A.), Broad Institute, Cambridge, MA; Cardiovascular Research Center (L.-C.W., P.T.E., S.A.L.), Center for Genomic Medicine (J.R., C.D.A.), J.P. Kistler Stroke Research Center (J.R., C.D.A.), and Cardiac Arrhythmia Service (P.T.E., S.A.L.), Massachusetts General Hospital, Boston; Department of Medicine (P.F.M., B.D.M.), Program for Personalized and Genomic Medicine, University of Maryland School of Medicine, Baltimore; National Heart, Lung, and Blood Institute's and Boston University's Framingham Heart Study (L.T., E.J.B.); Department of Biostatistics (L.T.) and Department of Epidemiology (E.J.B.), Boston University School of Public Health, MA; Geriatrics Research and Education Clinical Center (B.D.M.), Baltimore Veterans Administration Medical Center, MD; Cardiology Preventive Medicine Sections (E.J.B.), Evans Department of Medicine, Boston University School of Medicine; Department of Neurology (S.J.K.), University of Maryland School of Medicine; and Department of Neurology (S.J.K.), Veterans Affairs Medical Center, Baltimore, MD
| | - Christopher D Anderson
- Department of Genetics (S.L.P., P.I.W.d. B.), University Medical Center Utrecht, Utrecht University, The Netherlands; P.I.W.d.B. is now with Computational Genomics, Vertex Pharmaceuticals, Boston, MA; Li Ka Shing Centre for Health Information and Discovery (S.L.P.), The Big Data Institute, University of Oxford, United Kingdom; Program in Medical and Population Genetics (S.L.P., L.-C.W., S.H.C., J.R., P.T.E., S.A.L., C.D.A.), Broad Institute, Cambridge, MA; Cardiovascular Research Center (L.-C.W., P.T.E., S.A.L.), Center for Genomic Medicine (J.R., C.D.A.), J.P. Kistler Stroke Research Center (J.R., C.D.A.), and Cardiac Arrhythmia Service (P.T.E., S.A.L.), Massachusetts General Hospital, Boston; Department of Medicine (P.F.M., B.D.M.), Program for Personalized and Genomic Medicine, University of Maryland School of Medicine, Baltimore; National Heart, Lung, and Blood Institute's and Boston University's Framingham Heart Study (L.T., E.J.B.); Department of Biostatistics (L.T.) and Department of Epidemiology (E.J.B.), Boston University School of Public Health, MA; Geriatrics Research and Education Clinical Center (B.D.M.), Baltimore Veterans Administration Medical Center, MD; Cardiology Preventive Medicine Sections (E.J.B.), Evans Department of Medicine, Boston University School of Medicine; Department of Neurology (S.J.K.), University of Maryland School of Medicine; and Department of Neurology (S.J.K.), Veterans Affairs Medical Center, Baltimore, MD
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Bai J, Gladding PA, Stiles MK, Fedorov VV, Zhao J. Ionic and cellular mechanisms underlying TBX5/PITX2 insufficiency-induced atrial fibrillation: Insights from mathematical models of human atrial cells. Sci Rep 2018; 8:15642. [PMID: 30353147 PMCID: PMC6199257 DOI: 10.1038/s41598-018-33958-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 09/24/2018] [Indexed: 12/16/2022] Open
Abstract
Transcription factors TBX5 and PITX2 involve in the regulation of gene expression of ion channels and are closely associated with atrial fibrillation (AF), the most common cardiac arrhythmia in developed countries. The exact cellular and molecular mechanisms underlying the increased susceptibility to AF in patients with TBX5/PITX2 insufficiency remain unclear. In this study, we have developed and validated a novel human left atrial cellular model (TPA) based on the ten Tusscher-Panfilov ventricular cell model to systematically investigate how electrical remodeling induced by TBX5/PITX2 insufficiency leads to AF. Using our TPA model, we have demonstrated that spontaneous diastolic depolarization observed in atrial myocytes with TBX5-deletion can be explained by altered intracellular calcium handling and suppression of inward-rectifier potassium current (IK1). Additionally, our computer simulation results shed new light on the novel cellular mechanism underlying AF by indicating that the imbalance between suppressed outward current IK1 and increased inward sodium-calcium exchanger current (INCX) resulted from SR calcium leak leads to spontaneous depolarizations. Furthermore, our simulation results suggest that these arrhythmogenic triggers can be potentially suppressed by inhibiting sarcoplasmic reticulum (SR) calcium leak and reversing remodeled IK1. More importantly, this study has clinically significant implications on the drugs used for maintaining SR calcium homeostasis, whereby drugs such as dantrolene may confer significant improvement for the treatment of AF patients with TBX5/PITX2 insufficiency.
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Affiliation(s)
- Jieyun Bai
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand.
- School of Computer Science and Technology, Harbin Institute Technology, Harbin, China.
| | - Patrick A Gladding
- Department of Cardiology, Waitemata District Health Board, Auckland, New Zealand
| | | | - Vadim V Fedorov
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, United States of America
| | - Jichao Zhao
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand.
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Colman MA, Saxena P, Kettlewell S, Workman AJ. Description of the Human Atrial Action Potential Derived From a Single, Congruent Data Source: Novel Computational Models for Integrated Experimental-Numerical Study of Atrial Arrhythmia Mechanisms. Front Physiol 2018; 9:1211. [PMID: 30245635 PMCID: PMC6137999 DOI: 10.3389/fphys.2018.01211] [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] [Received: 05/03/2018] [Accepted: 08/13/2018] [Indexed: 11/13/2022] Open
Abstract
Introduction: The development of improved diagnosis, management, and treatment strategies for human atrial fibrillation (AF) is a significant and important challenge in order to improve quality of life for millions and reduce the substantial social-economic costs of the condition. As a complex condition demonstrating high variability and relation to other cardiac conditions, the study of AF requires approaches from multiple disciplines including single-cell experimental electrophysiology and computational modeling. Models of human atrial cells are less well parameterized than those of the human ventricle or other mammal species, largely due to the inherent challenges in patch clamping human atrial cells. Such challenges include, frequently, unphysiologically depolarized resting potentials and thus injection of a compensatory hyperpolarizing current, as well as detecting certain ion currents which may be disrupted by the cell isolation process. The aim of this study was to develop a laboratory specific model of human atrial electrophysiology which reproduces exactly the conditions of isolated-cell experiments, including testing of multiple experimental interventions. Methods: Formulations for the primary ion currents characterized by isolated-cell experiments in the Workman laboratory were fit directly to voltage-clamp data; the fast sodium-current was parameterized based on experiments relating resting membrane potential to maximal action potential upstroke velocity; compensatory hyperpolarizing current was included as a constant applied current. These formulations were integrated with three independent human atrial cell models to provide a family of novel models. Extrapolated intact-cell models were developed through removal of the hyperpolarizing current and introduction of terminal repolarization potassium currents. Results: The isolated-cell models quantitatively reproduced experimentally measured properties of excitation in both control and pharmacological and dynamic-clamp interventions. Comparison of isolated and intact-cell models highlighted the importance of reproducing this cellular environment when comparing experimental and simulation data. Conclusion: We have developed a laboratory specific model of the human atrial cell which directly reproduces the experimental isolated-cell conditions and captures human atrial excitation properties. The model may be particularly useful for directly relating model to experiment, and offers a complementary tool to the available set of human atrial cell models with specific advantages resulting from the congruent input data source.
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Affiliation(s)
- Michael A Colman
- Leeds Computational Physiology Lab, School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Priyanka Saxena
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Sarah Kettlewell
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Antony J Workman
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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Piña PG, Chicos AB. Early Cardioversion in Atrial Fibrillation: Earlier Is Better, but Not Always and (Maybe) Not Immediately. Curr Atheroscler Rep 2017; 19:3. [PMID: 28108860 DOI: 10.1007/s11883-017-0638-1] [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] [Indexed: 11/27/2022]
Abstract
Atrial fibrillation (AF) is the most common cardiac arrhythmia in humans. One of its important features is the tendency to become more persistent over time, even in the absence of underlying progressive heart disease. Conversion and maintenance of sinus rhythm by pharmacological or electrical methods become increasingly difficult the longer the arrhythmia persists. Electrical, mechanical, structural, and autonomic remodeling processes have been implicated in the mechanisms of AF initiation, perpetuation, and progression. Prevention or reversal of these remodeling processes can halt the progression of the disease. Cardioversion is a powerful tool and rhythm control is a widely used strategy in the management of AF. However, important questions remain unanswered regarding not only if, but also when to perform cardioversion. There are observations from past trials and clinical situations that support attempting to restore sinus rhythm, but further prospective randomized clinical trials are needed. Optimal timing of cardioversion remains somewhat uncertain, but it appears to be some time after the first few hours and before the first few months: the earlier, the better, but not always, and maybe not immediately, and it has to be tailored to the clinical situation and its many variables. This review is intended to summarize the evidence supporting early intervention for the prevention of remodeling in patients with AF.
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Affiliation(s)
- Paloma G Piña
- Clinical Cardiac Electrophysiology, Bluhm Cardiovascular Institute, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Alexandru B Chicos
- Clinical Cardiac Electrophysiology, Bluhm Cardiovascular Institute, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA.
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Liang JJ, Silvestry FE. Mechanistic insights into mitral regurgitation due to atrial fibrillation: “Atrial functional mitral regurgitation”. Trends Cardiovasc Med 2016; 26:681-689. [DOI: 10.1016/j.tcm.2016.04.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 04/26/2016] [Accepted: 04/27/2016] [Indexed: 10/21/2022]
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30
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HENMI RYUTA, EJIMA KOICHIRO, SHODA MORIO, YAGISHITA DAIGO, HAGIWARA NOBUHISA. Interatrial Conduction Time Can Predict New-Onset Atrial Fibrillation After Radiofrequency Ablation of Isolated, Typical Atrial Flutter. J Cardiovasc Electrophysiol 2016; 27:1293-1297. [DOI: 10.1111/jce.13040] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 06/06/2016] [Accepted: 07/09/2016] [Indexed: 02/05/2023]
Affiliation(s)
- RYUTA HENMI
- Department of Cardiology; Tokyo Women's Medical University; Tokyo Japan
| | - KOICHIRO EJIMA
- Department of Cardiology; Tokyo Women's Medical University; Tokyo Japan
| | - MORIO SHODA
- Department of Cardiology; Tokyo Women's Medical University; Tokyo Japan
| | - DAIGO YAGISHITA
- Department of Cardiology; Tokyo Women's Medical University; Tokyo Japan
| | - NOBUHISA HAGIWARA
- Department of Cardiology; Tokyo Women's Medical University; Tokyo Japan
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Lee JM, Lee H, Janardhan AH, Park J, Joung B, Pak HN, Lee MH, Kim SS, Hwang HJ. Prolonged atrial refractoriness predicts the onset of atrial fibrillation: A 12-year follow-up study. Heart Rhythm 2016; 13:1575-80. [DOI: 10.1016/j.hrthm.2016.03.037] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Indexed: 11/27/2022]
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32
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AL ABED AMR, LOVELL NIGELH, DOKOS SOCRATES. Local Heterogeneous Electrical Restitution Properties of Rabbit Atria. J Cardiovasc Electrophysiol 2016; 27:743-53. [DOI: 10.1111/jce.12968] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 02/19/2016] [Accepted: 02/22/2016] [Indexed: 11/30/2022]
Affiliation(s)
- AMR AL ABED
- Graduate School of Biomedical Engineering University of New South Wales Australia Sydney Australia
| | - NIGEL H. LOVELL
- Graduate School of Biomedical Engineering University of New South Wales Australia Sydney Australia
| | - SOCRATES DOKOS
- Graduate School of Biomedical Engineering University of New South Wales Australia Sydney Australia
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33
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Ko D, Rahman F, Schnabel RB, Yin X, Benjamin EJ, Christophersen IE. Atrial fibrillation in women: epidemiology, pathophysiology, presentation, and prognosis. Nat Rev Cardiol 2016; 13:321-32. [PMID: 27053455 DOI: 10.1038/nrcardio.2016.45] [Citation(s) in RCA: 211] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Atrial fibrillation (AF) is the most common sustained arrhythmia in women and men worldwide. During the past century, a range of risk factors has been associated with AF, severe complications from the arrhythmia have been identified, and its prevalence has been increasing steadily. Whereas evidence has accumulated regarding sex-specific differences in coronary heart disease and stroke, the differences between women and men with AF has received less attention. We review the current literature on sex-specific differences in the epidemiology of AF, including incidence, prevalence, risk factors, and genetics, and in the pathophysiology and the clinical presentation and prognosis of patients with this arrhythmia. We highlight current knowledge gaps and areas that warrant future research, which might advance understanding of variation in the risk factors and complications of AF, and ultimately aid more-tailored management of the arrhythmia.
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Affiliation(s)
- Darae Ko
- Section of General Internal Medicine, Boston Medical Center, Boston University School of Medicine
| | - Faisal Rahman
- Department of Internal Medicine, Boston Medical Center, Boston University School of Medicine
| | - Renate B Schnabel
- Department of General and Interventional Cardiology, University Heart Center Hamburg, Martinistrasse 52, 20246 Hamburg, Germany.,DZHK (German Center for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Oudenarder Strasse 16, 13347 Berlin, Germany
| | - Xiaoyan Yin
- Boston University and National Heart, Lung, and Blood Institute's Framingham Heart Study, 73 Mount Wayte Avenue Framingham, Massachusetts 01702, USA.,Department of Biostatistics, Boston University School of Public Health
| | - Emelia J Benjamin
- Boston University and National Heart, Lung, and Blood Institute's Framingham Heart Study, 73 Mount Wayte Avenue Framingham, Massachusetts 01702, USA.,Sections of Cardiovascular Medicine and Preventive Medicine, Boston Medical Center, Boston University School of Medicine, 72 East Concord Street, Boston, Massachusetts 02118, USA.,Department of Epidemiology, Boston University School of Public Health, 715 Albany Street, Boston, Massachusetts 02118, USA
| | - Ingrid E Christophersen
- Cardiovascular Research Center, Massachusetts General Hospital, 149 13th Street, Charlestown, Massachusetts, 02129, USA.,Department of Medical Research, Bærum Hospital, Vestre Viken Hospital Trust, Sogneprest Munthe-kaas vei 100, 1346 Gjettum, Norway
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Lee YS, Hwang M, Song JS, Li C, Joung B, Sobie EA, Pak HN. The Contribution of Ionic Currents to Rate-Dependent Action Potential Duration and Pattern of Reentry in a Mathematical Model of Human Atrial Fibrillation. PLoS One 2016; 11:e0150779. [PMID: 26964092 PMCID: PMC4795605 DOI: 10.1371/journal.pone.0150779] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 02/17/2016] [Indexed: 11/19/2022] Open
Abstract
Persistent atrial fibrillation (PeAF) in humans is characterized by shortening of action potential duration (APD) and attenuation of APD rate-adaptation. However, the quantitative influences of particular ionic current alterations on rate-dependent APD changes, and effects on patterns of reentry in atrial tissue, have not been systematically investigated. Using mathematical models of human atrial cells and tissue and performing parameter sensitivity analysis, we evaluated the quantitative contributions to action potential (AP) shortening and APD rate-adaptation of ionic current remodeling seen with PeAF. Ionic remodeling in PeAF was simulated by reducing L-type Ca2+ channel current (ICaL), increasing inward rectifier K+ current (IK1) and modulating five other ionic currents. Parameter sensitivity analysis, which quantified how each ionic current influenced APD in control and PeAF conditions, identified interesting results, including a negative effect of Na+/Ca2+ exchange on APD only in the PeAF condition. At high pacing rate (2 Hz), electrical remodeling in IK1 alone accounts for the APD reduction of PeAF, but at slow pacing rate (0.5 Hz) both electrical remodeling in ICaL alone (-70%) and IK1 alone (+100%) contribute equally to the APD reduction. Furthermore, AP rate-adaptation was affected by IKur in control and by INaCa in the PeAF condition. In a 2D tissue model, a large reduction (-70%) of ICaL becomes a dominant factor leading to a stable spiral wave in PeAF. Our study provides a quantitative and unifying understanding of the roles of ionic current remodeling in determining rate-dependent APD changes at the cellular level and spatial reentry patterns in tissue.
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Affiliation(s)
- Young-Seon Lee
- Yonsei University Health System, Seoul, Republic of Korea
| | - Minki Hwang
- Yonsei University Health System, Seoul, Republic of Korea
| | - Jun-Seop Song
- Yonsei University Health System, Seoul, Republic of Korea
| | - Changyong Li
- Yonsei University Health System, Seoul, Republic of Korea
| | - Boyoung Joung
- Yonsei University Health System, Seoul, Republic of Korea
| | - Eric A. Sobie
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
- * E-mail: (HNP); (EAS)
| | - Hui-Nam Pak
- Yonsei University Health System, Seoul, Republic of Korea
- * E-mail: (HNP); (EAS)
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35
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Genome-wide screening identifies a KCNIP1 copy number variant as a genetic predictor for atrial fibrillation. Nat Commun 2016; 7:10190. [PMID: 26831368 PMCID: PMC4740744 DOI: 10.1038/ncomms10190] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 11/16/2015] [Indexed: 01/01/2023] Open
Abstract
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. Previous genome-wide association studies had identified single-nucleotide polymorphisms in several genomic regions to be associated with AF. In human genome, copy number variations (CNVs) are known to contribute to disease susceptibility. Using a genome-wide multistage approach to identify AF susceptibility CNVs, we here show a common 4,470-bp diallelic CNV in the first intron of potassium interacting channel 1 gene (KCNIP1) is strongly associated with AF in Taiwanese populations (odds ratio=2.27 for insertion allele; P=6.23 × 10(-24)). KCNIP1 insertion is associated with higher KCNIP1 mRNA expression. KCNIP1-encoded protein potassium interacting channel 1 (KCHIP1) is physically associated with potassium Kv channels and modulates atrial transient outward current in cardiac myocytes. Overexpression of KCNIP1 results in inducible AF in zebrafish. In conclusions, a common CNV in KCNIP1 gene is a genetic predictor of AF risk possibly pointing to a functional pathway.
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36
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Progression of atrial remodeling in patients with high-burden atrial fibrillation: Implications for early ablative intervention. Heart Rhythm 2016; 13:331-9. [DOI: 10.1016/j.hrthm.2015.10.028] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Indexed: 11/20/2022]
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37
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Mesubi OO, Anderson ME. Atrial remodelling in atrial fibrillation: CaMKII as a nodal proarrhythmic signal. Cardiovasc Res 2016; 109:542-57. [PMID: 26762270 DOI: 10.1093/cvr/cvw002] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 01/05/2016] [Indexed: 01/10/2023] Open
Abstract
CaMKII is a serine-threonine protein kinase that is abundant in myocardium. Emergent evidence suggests that CaMKII may play an important role in promoting atrial fibrillation (AF) by targeting a diverse array of proteins involved in membrane excitability, cell survival, calcium homeostasis, matrix remodelling, inflammation, and metabolism. Furthermore, CaMKII inhibition appears to protect against AF in animal models and correct proarrhythmic, defective intracellular Ca(2+) homeostasis in fibrillating human atrial cells. This review considers current concepts and evidence from animal and human studies on the role of CaMKII in AF.
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Affiliation(s)
- Olurotimi O Mesubi
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA Department of Medicine, The Johns Hopkins University School of Medicine, 1830 E. Monument Street, Suite 9026, Baltimore, MD 21287, USA
| | - Mark E Anderson
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA Department of Medicine, The Johns Hopkins University School of Medicine, 1830 E. Monument Street, Suite 9026, Baltimore, MD 21287, USA Department of Physiology and the Program in Cellular and Molecular Medicine, The Johns Hopkins School of Medicine, Baltimore, MD, USA
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38
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Hansen BJ, Zhao J, Csepe TA, Moore BT, Li N, Jayne LA, Kalyanasundaram A, Lim P, Bratasz A, Powell KA, Simonetti OP, Higgins RSD, Kilic A, Mohler PJ, Janssen PML, Weiss R, Hummel JD, Fedorov VV. Atrial fibrillation driven by micro-anatomic intramural re-entry revealed by simultaneous sub-epicardial and sub-endocardial optical mapping in explanted human hearts. Eur Heart J 2015; 36:2390-401. [PMID: 26059724 DOI: 10.1093/eurheartj/ehv233] [Citation(s) in RCA: 291] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 05/08/2015] [Indexed: 11/12/2022] Open
Abstract
AIMS The complex architecture of the human atria may create physical substrates for sustained re-entry to drive atrial fibrillation (AF). The existence of sustained, anatomically defined AF drivers in humans has been challenged partly due to the lack of simultaneous endocardial-epicardial (Endo-Epi) mapping coupled with high-resolution 3D structural imaging. METHODS AND RESULTS Coronary-perfused human right atria from explanted diseased hearts (n = 8, 43-72 years old) were optically mapped simultaneously by three high-resolution CMOS cameras (two aligned Endo-Epi views (330 µm2 resolution) and one panoramic view). 3D gadolinium-enhanced magnetic resonance imaging (GE-MRI, 80 µm3 resolution) revealed the atrial wall structure varied in thickness (1.0 ± 0.7-6.8 ± 2.4 mm), transmural fiber angle differences, and interstitial fibrosis causing transmural activation delay from 23 ± 11 to 43 ± 22 ms at increased pacing rates. Sustained AF (>90 min) was induced by burst pacing during pinacidil (30-100 µM) perfusion. Dual-sided sub-Endo-sub-Epi optical mapping revealed that AF was driven by spatially and temporally stable intramural re-entry with 107 ± 50 ms cycle length and transmural activation delay of 67 ± 31 ms. Intramural re-entrant drivers were captured primarily by sub-Endo mapping, while sub-Epi mapping visualized re-entry or 'breakthrough' patterns. Re-entrant drivers were anchored on 3D micro-anatomic tracks (15.4 ± 2.2 × 6.0 ± 2.3 mm2, 2.9 ± 0.9 mm depth) formed by atrial musculature characterized by increased transmural fiber angle differences and interstitial fibrosis. Targeted radiofrequency ablation of the tracks verified these re-entries as drivers of AF. CONCLUSIONS Integrated 3D structural-functional mapping of diseased human right atria ex vivo revealed that the complex atrial microstructure caused significant differences between Endo vs. Epi activation during pacing and sustained AF driven by intramural re-entry anchored to fibrosis-insulated atrial bundles.
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Affiliation(s)
- Brian J Hansen
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, 300 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210-1218, USA
| | - Jichao Zhao
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Thomas A Csepe
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, 300 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210-1218, USA
| | - Brandon T Moore
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, 300 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210-1218, USA
| | - Ning Li
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, 300 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210-1218, USA
| | - Laura A Jayne
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, 300 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210-1218, USA
| | - Anuradha Kalyanasundaram
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, 300 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210-1218, USA
| | - Praise Lim
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Anna Bratasz
- Small Animal Imaging Core, The Ohio State University Wexner Medical Center, Columbus, OH, USA Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Kimerly A Powell
- Small Animal Imaging Core, The Ohio State University Wexner Medical Center, Columbus, OH, USA Department of Biomedical Informatics, College of Medicine, The Ohio State University, Columbus, OH, USA Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Orlando P Simonetti
- Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Robert S D Higgins
- Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA Department of Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Ahmet Kilic
- Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA Department of Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Peter J Mohler
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, 300 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210-1218, USA Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Paul M L Janssen
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, 300 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210-1218, USA Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Raul Weiss
- Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - John D Hummel
- Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Vadim V Fedorov
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, 300 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210-1218, USA Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA
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Bates ORJ, Suki B, Spector PS, Bates JHT. Structural defects lead to dynamic entrapment in cardiac electrophysiology. PLoS One 2015; 10:e0119535. [PMID: 25756656 PMCID: PMC4354910 DOI: 10.1371/journal.pone.0119535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 01/24/2015] [Indexed: 11/18/2022] Open
Abstract
Biological networks are typically comprised of many parts whose interactions are governed by nonlinear dynamics. This potentially imbues them with the ability to support multiple attractors, and therefore to exhibit correspondingly distinct patterns of behavior. In particular, multiple attractors have been demonstrated for the electrical activity of the diseased heart in situations where cardioversion is able to convert a reentrant arrhythmia to a stable normal rhythm. Healthy hearts, however, are typically resilient to abnormal rhythms. This raises the question as to how a healthy cardiac cell network must be altered so that it can support multiple distinct behaviors. Here we demonstrate how anatomic defects can give rise to multi-stability in the heart as a function of the electrophysiological properties of the cardiac tissue and the timing of activation of ectopic foci. This leads to a form of hysteretic behavior, which we call dynamic entrapment, whereby the heart can become trapped in aberrant attractor as a result of a transient change in tissue properties. We show that this can lead to a highly inconsistent relationship between clinical symptoms and underlying pathophysiology, which raises the possibility that dynamic entrapment may underlie other forms of chronic idiopathic illness.
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Affiliation(s)
- Oliver R. J. Bates
- Boston University College of Engineering, 44 Cummington Mall, Boston, Massachusetts, 02215, United States of America
| | - Bela Suki
- Boston University College of Engineering, 44 Cummington Mall, Boston, Massachusetts, 02215, United States of America
| | - Peter S. Spector
- University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, Vermont, 05405, United States of America
| | - Jason H. T. Bates
- University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, Vermont, 05405, United States of America
- * E-mail:
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Baczko I, Liknes D, Yang W, Hamming KC, Searle G, Jaeger K, Husti Z, Juhasz V, Klausz G, Pap R, Saghy L, Varro A, Dolinsky V, Wang S, Rauniyar V, Hall D, Dyck JR, Light PE. Characterization of a novel multifunctional resveratrol derivative for the treatment of atrial fibrillation. Br J Pharmacol 2014; 171:92-106. [PMID: 24102184 DOI: 10.1111/bph.12409] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 08/28/2013] [Accepted: 09/07/2013] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND AND PURPOSE Atrial fibrillation (AF) is the most common cardiac arrhythmia and is associated with an increased risk for stroke, heart failure and cardiovascular-related mortality. Candidate targets for anti-AF drugs include a potassium channel K(v)1.5, and the ionic currents I(KACh) and late I(Na), along with increased oxidative stress and activation of NFAT-mediated gene transcription. As pharmacological management of AF is currently suboptimal, we have designed and characterized a multifunctional small molecule, compound 1 (C1), to target these ion channels and pathways. EXPERIMENTAL APPROACH We made whole-cell patch-clamp recordings of recombinant ion channels, human atrial I(Kur), rat atrial I(KACh), cellular recordings of contractility and calcium transient measurements in tsA201 cells, human atrial samples and rat myocytes. We also used a model of inducible AF in dogs. KEY RESULTS C1 inhibited human peak and late K(v)1.5 currents, frequency-dependently, with IC₅₀ of 0.36 and 0.11 μmol·L(-1) respectively. C1 inhibited I(KACh)(IC₅₀ of 1.9 μmol·L(-1)) and the Na(v)1.5 sodium channel current (IC₅₀s of 3 and 1 μmol·L(-1) for peak and late components respectively). C1 (1 μmol·L(-1)) significantly delayed contractile and calcium dysfunction in rat ventricular myocytes treated with 3 nmol·L(-1) sea anemone toxin (ATX-II). C1 weakly inhibited the hERG channel and maintained antioxidant and NFAT-inhibitory properties comparable to the parent molecule, resveratrol. In a model of inducible AF in conscious dogs, C1 (1 mg·kg(-1)) reduced the average and total AF duration. CONCLUSION AND IMPLICATIONS C1 behaved as a promising multifunctional small molecule targeting a number of key pathways involved in AF.
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Affiliation(s)
- Istvan Baczko
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
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Koivumäki JT, Seemann G, Maleckar MM, Tavi P. In silico screening of the key cellular remodeling targets in chronic atrial fibrillation. PLoS Comput Biol 2014; 10:e1003620. [PMID: 24853123 PMCID: PMC4031057 DOI: 10.1371/journal.pcbi.1003620] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 03/30/2014] [Indexed: 02/07/2023] Open
Abstract
Chronic atrial fibrillation (AF) is a complex disease with underlying changes in electrophysiology, calcium signaling and the structure of atrial myocytes. How these individual remodeling targets and their emergent interactions contribute to cell physiology in chronic AF is not well understood. To approach this problem, we performed in silico experiments in a computational model of the human atrial myocyte. The remodeled function of cellular components was based on a broad literature review of in vitro findings in chronic AF, and these were integrated into the model to define a cohort of virtual cells. Simulation results indicate that while the altered function of calcium and potassium ion channels alone causes a pronounced decrease in action potential duration, remodeling of intracellular calcium handling also has a substantial impact on the chronic AF phenotype. We additionally found that the reduction in amplitude of the calcium transient in chronic AF as compared to normal sinus rhythm is primarily due to the remodeling of calcium channel function, calcium handling and cellular geometry. Finally, we found that decreased electrical resistance of the membrane together with remodeled calcium handling synergistically decreased cellular excitability and the subsequent inducibility of repolarization abnormalities in the human atrial myocyte in chronic AF. We conclude that the presented results highlight the complexity of both intrinsic cellular interactions and emergent properties of human atrial myocytes in chronic AF. Therefore, reversing remodeling for a single remodeled component does little to restore the normal sinus rhythm phenotype. These findings may have important implications for developing novel therapeutic approaches for chronic AF.
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Affiliation(s)
- Jussi T. Koivumäki
- Simula Research Laboratory, Center for Cardiological Innovation and Center for Biomedical Computing, Oslo, Norway
- Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Gunnar Seemann
- Institute of Biomedical Engineering, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Mary M. Maleckar
- Simula Research Laboratory, Center for Cardiological Innovation and Center for Biomedical Computing, Oslo, Norway
| | - Pasi Tavi
- Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
- * E-mail:
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42
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Zamani P, Verdino RJ. Management of Atrial Fibrillation. J Intensive Care Med 2014; 30:484-98. [PMID: 24828991 DOI: 10.1177/0885066614534603] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 03/03/2014] [Indexed: 12/19/2022]
Abstract
Atrial fibrillation remains the most prevalent cardiac arrhythmia, and its incidence is increasing as the population ages. Common conditions associated with an increased incidence include advanced age, hypertension, heart failure, and valvular heart disease. Patients with atrial fibrillation may complain of palpitations, fatigue, and decreased exercise tolerance or may be completely asymptomatic. Options for treating patients who experience atrial fibrillation include rate-controlling drugs such as digoxin, β-blockers, and calcium channel blockers or a rhythm-controlling strategy with agents such as sodium channel blockers and potassium channel blockers. Atrial fibrillation increases the risk of stroke due to atrial thrombus formation and embolization. Anticoagulation with the vitamin K antagonist, warfarin, remains the most widely prescribed treatment option to decrease stroke risk. Several other antithrombotic agents have recently become available and offer excellent alternatives to warfarin. Catheter ablation can be undertaken as a nonpharmacologic rhythm control option with varying degrees of success depending on duration of atrial fibrillation and follow-up time from the procedure. This review article further describes the management options for patients presenting with atrial fibrillation.
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Affiliation(s)
- Payman Zamani
- Division of Cardiovascular Medicine, Perelman School of Medicine of the University of Pennsylvania, Philadelphia, PA, USA
| | - Ralph J Verdino
- Division of Cardiovascular Medicine, Perelman School of Medicine of the University of Pennsylvania, Philadelphia, PA, USA
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43
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Sasaki N, Watanabe I, Kogawa R, Sonoda K, Takahashi K, Okumura Y, Ohkubo K, Nakai T, Hirayama A. Effects of intravenous amiodarone and ibutilide on action potential duration and atrial conduction kinetics in patients with persistent atrial fibrillation. Int Heart J 2014; 55:244-8. [PMID: 24806377 DOI: 10.1536/ihj.13-254] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Class III antiarrhythmic drugs have been shown to be effective for termination of atrial fibrillation (AF). The aim of this study was to determine the steady state and non-steady state effects of amiodarone and ibutilide on the atrial monophasic action potential (MAP) duration (MAPD), effective refractory period (ERP), and intra-atrial conduction time (IACT) in human persistent AF.Fourteen patients with persistent AF who underwent internal atrial defibrillation were included in the study. The atrial MAP was recorded at the high right atrium. IACT was measured from the pacing spike to the distal coronary sinus. MAPD and IACT were assessed during the steady state and at the shortest diastolic interval (DI) at a basic cycle length (CL) of 600 msec and after a premature stimulus. Amiodarone did not affect MAPD or the ERP at the basic CL, but it increased MAPD at the shortest DI. Amiodarone increased IACT at both the basic CL and the shortest DI. Ibutilide increased the MAPD and ERP at the basic CL and at the shortest DI. Ibutilide did not affect IACT at the basic CL or the shortest DI.Ibutilide increases atrial MAPD not only in the steady state but also at the shortest DI, but it does not affect IACT in patients with persistent AF. Amiodarone does not affect MAPD or ERP, but it increases IACT in the steady state, and it increases MAPD and IACT at the shortest DI.
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Affiliation(s)
- Naoko Sasaki
- Division of Cardiology, Department of Medicine, Nihon University School of Medicine
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Loose S, Mueller J, Wettwer E, Knaut M, Ford J, Milnes J, Ravens U. Effects of IKur blocker MK-0448 on human right atrial action potentials from patients in sinus rhythm and in permanent atrial fibrillation. Front Pharmacol 2014; 5:26. [PMID: 24624083 PMCID: PMC3940943 DOI: 10.3389/fphar.2014.00026] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 02/12/2014] [Indexed: 11/30/2022] Open
Abstract
Selective blockers of the Kv1.5 channel have been developed for the treatment of atrial fibrillation (AF), but little is known how these atrial-selective drugs affect human action potentials (APs). Therefore we have investigated the Kv1.5 blocker MK-0448 (N-{6-[(1S)-1-(4-fluorophenyl)-2,2-di(pyridin-3-yl)ethyl]pyridin-2-yl}methanesulfon- amide) in right atrial trabeculae from patients in sinus rhythm (SR), permanent AF (>6 months), and intermittent AF. MK-0448 blocked Kv1.5 current in an expression system and concentration-dependently elevated the plateau phase of atrial APs. In SR preparations stimulated at 1 Hz, MK-0448 (3 μM) shortened action potential duration at 90% of repolarization (APD90) and effective refractory period (ERP), but in permanent AF preparations, MK-0448 prolonged APD90 and ERP. The effects of MK-0448 in intermittent AF resembled those in SR preparations. Block of IKs is probably more prominent in AF because of reduced repolarization reserve due to AF-induced remodeling.
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Affiliation(s)
- Simone Loose
- Department of Pharmacology and Toxicology, Medical Faculty Carl Gustav Carus, Dresden University of Technology Dresden, Germany
| | - Judith Mueller
- Department of Pharmacology and Toxicology, Medical Faculty Carl Gustav Carus, Dresden University of Technology Dresden, Germany
| | - Erich Wettwer
- Department of Pharmacology and Toxicology, Medical Faculty Carl Gustav Carus, Dresden University of Technology Dresden, Germany
| | - Michael Knaut
- Clinic for Cardiac Surgery, Heart Center Dresden Dresden, Germany
| | | | | | - Ursula Ravens
- Department of Pharmacology and Toxicology, Medical Faculty Carl Gustav Carus, Dresden University of Technology Dresden, Germany
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Differential effects of the peroxynitrite donor, SIN-1, on atrial and ventricular myocyte electrophysiology. J Cardiovasc Pharmacol 2013; 61:401-7. [PMID: 23364607 DOI: 10.1097/fjc.0b013e31828748ca] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Oxidative stress has been implicated in the pathogenesis of heart failure and atrial fibrillation and can result in increased peroxynitrite production in the myocardium. Atrial and ventricular canine cardiac myocytes were superfused with 3-morpholinosydnonimine-N-ethylcarbamide (SIN-1), a peroxynitrite donor, to evaluate the acute electrophysiologic effects of peroxynitrite. Perforated whole-cell patch clamp techniques were used to record action potentials. SIN-1 (200 µM) increased the action potential duration (APD) in atrial and ventricular myocytes; however, in the atria, APD prolongation was rate independent, whereas in the ventricle APD, prolongation was rate dependent. In addition to prolongation of the action potential, beat-to-beat variability of repolarization was significantly increased in ventricular but not in atrial myocytes. We examined the contribution of intracellular calcium cycling to the effects of SIN-1 by treating myocytes with the SERCA blocker, thapsigargin (5-10 µM). Inhibition of calcium cycling prevented APD prolongation in the atrial and ventricular myocytes, and prevented the SIN-1-induced increase in ventricular beat-to-beat APD variability. Collectively, these data demonstrate that peroxynitrite affects atrial and ventricular electrophysiology differentially. A detailed understanding of oxidative modulation of electrophysiology in specific chambers is critical to optimize therapeutic approaches for cardiac diseases.
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46
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Sonoda K, Watanabe I, Ohkubo K, Okumura Y, Kofune M, Sasaki N, Kogawa R, Mano H, Nakai T, Hirayama A. Rate-dependent electrophysiologic effects of the class III antiarrhythmic drugs nifekalant, amiodarone, and ibutilide on the atrium in patients with persistent atrial fibrillation. Int Heart J 2013; 54:279-84. [PMID: 24097216 DOI: 10.1536/ihj.54.279] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Persistent atrial fibrillation (AF) is characterized by electrical remodeling, ie, marked decreases in the atrial effective refractory period (ERP), ERP rate adaptation, and atrial conduction velocity. Little information is available on the effects of class III antiarrhythmic drugs on the remodeled atrium. We studied the effects of the class III antiarrhythmic drugs nifekalant, ibutilide, and amiodarone on rate-dependent changes in atrial action potential duration in patients with persistent AF. Right atrial (RA) monophasic action potential duration (MAPD) and intra-atrial conduction time (IACT) were measured at pacing cycle lengths (CLs) of 800, 700, 600, 500, 400, 350, 300, and 250 ms before and after administration of nifekalant (0.4 mg/kg + 0.3 mg/kg/hr, iv), amiodarone (5 mg/kg, iv), or ibutilide (0.01 mg/kg, iv) in 31 patients after successful internal cardioversion of chronic AF of > 2 months duration. Nifekalant and ibutilide significantly increased RA MAPD and the ERP at each CL in a reverse rate-dependent manner. Amiodarone did not affect RA MAPD. Nifekalant did not affect IACT, whereas amiodarone increased IACT at each CL in a rate-dependent manner, and ibutilide increased IACT at CLs ≤ 350 ms. The atrial electrophysiologic effects of the class III antiarrhythmic drugs nifekalant, amiodarone, and ibutilide differ, depending on the degree of electrical and structural remodeling and the effects of the drugs on the depolarizing and repolarizing currents.
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Affiliation(s)
- Kazumasa Sonoda
- Division of Cardiology, Department of Medicine, Nihon University School of Medicine
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47
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Nasso G, Bonifazi R, Romano V, Brigiani MS, Fiore F, Bartolomucci F, Lamarra M, Fattouch K, Rosano G, Gaudino M, Spirito R, Gaudio C, Speziale G. Increased plasma homocysteine predicts arrhythmia recurrence after minimally invasive epicardial ablation for nonvalvular atrial fibrillation. J Thorac Cardiovasc Surg 2013; 146:848-53. [DOI: 10.1016/j.jtcvs.2012.07.099] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 07/11/2012] [Accepted: 07/31/2012] [Indexed: 11/26/2022]
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Delaney JT, Muhammad R, Shi Y, Schildcrout JS, Blair M, Short L, Roden DM, Darbar D. Common SCN10A variants modulate PR interval and heart rate response during atrial fibrillation. Europace 2013; 16:485-90. [PMID: 24072447 DOI: 10.1093/europace/eut278] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
AIMS SCN10A encodes the sodium channel Nav1.8 implicated by genome-wide association studies as a modulator of atrioventricular conduction (PR interval). In a cohort of patients with atrial fibrillation (AF), we examined whether there was an association between common variants in SCN10A and both the PR interval during normal sinus rhythm and the heart rate response during AF. METHODS AND RESULTS Patients prospectively enrolled in the Vanderbilt AF registry with electrocardiograms in normal sinus rhythm and/or AF within 1 year of enrollment were genotyped for two common SCN10A variants rs6795970 and rs12632942. Both variants were associated with the PR interval duration in a gene-dose effect on unadjusted analysis; after adjustment for the covariates age, gender, body mass index, hypertension, congestive heart failure, and medication usage, the association remained for rs6795970 only (P = 0.012, partial R(2) = 0.0139). On unadjusted analysis, heart rate response during AF was associated with rs6795970 (P = 0.035, partial R(2) = 0.015), but not with rs12632942 (P = 0.89), and neither association was significant after adjustment for covariates. CONCLUSION The common variant rs6795970 in SCN10A is associated with the PR interval duration among healthy patients and those with AF. In addition, this single nucleotide polymorphism trended towards an association with heart rate response during AF indicating the importance of this common SCN10A polymorphism as a marker of atrioventricular conduction.
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Affiliation(s)
- Jessica T Delaney
- Division of Cardiovascular Medicine, Departments of Medicine, Vanderbilt University School of Medicine, 2215B Garland Avenue, Room 1275 MRB IV, Room 1275 MRB IV, Nashville, TN 37232-6602, USA
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In-silico modeling of atrial repolarization in normal and atrial fibrillation remodeled state. Med Biol Eng Comput 2013; 51:1105-19. [PMID: 23864549 DOI: 10.1007/s11517-013-1090-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 05/21/2013] [Indexed: 10/26/2022]
Abstract
Atrial fibrillation (AF) is the most common cardiac arrhythmia, and the total number of AF patients is constantly increasing. The mechanisms leading to and sustaining AF are not completely understood yet. Heterogeneities in atrial electrophysiology seem to play an important role in this context. Although some heterogeneities have been used in in-silico human atrial modeling studies, they have not been thoroughly investigated. In this study, the original electrophysiological (EP) models of Courtemanche et al., Nygren et al. and Maleckar et al. were adjusted to reproduce action potentials in 13 atrial regions. The parameter sets were validated against experimental action potential duration data and ECG data from patients with AV block. The use of the heterogeneous EP model led to a more synchronized repolarization sequence in a variety of 3D atrial anatomical models. Combination of the heterogeneous EP model with a model of persistent AF-remodeled electrophysiology led to a drastic change in cell electrophysiology. Simulated Ta-waves were significantly shorter under the remodeling. The heterogeneities in cell electrophysiology explain the previously observed Ta-wave effects. The results mark an important step toward the reliable simulation of the atrial repolarization sequence, give a deeper understanding of the mechanism of atrial repolarization and enable further clinical investigations.
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50
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Wang X, Li Y, Liu L, Hu SS, Song YH, Wang W. The role of matrix metalloproteinase-2 in the treatment of atrial fibrillation recurrence after a radiofrequency modified maze procedure. Cardiology 2013; 126:62-8. [PMID: 23867576 DOI: 10.1159/000351980] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 05/09/2013] [Indexed: 11/19/2022]
Abstract
BACKGROUND AND OBJECTIVE Our study aimed to elucidate the potential clinical and molecular issues in recurrent atrial fibrillation (AF) following a radiofrequency modified maze procedure in patients with rheumatic valvular disease and persistent AF. METHODS AND RESULTS Eighty patients with rheumatic valvular disease and persistent AF (lasting more than 6 months) who had undergone a radiofrequency modified maze procedure and mitral valve replacement were enrolled into this single-center pilot study and were followed up for another 6 months. Their clinical characteristics were analyzed and the expression of matrix metalloproteinase (MMP)-2 including its specific inhibitor and collagen volume fraction (CVF) was also assessed. During the 6-month follow-up, 24 subjects had recurrent AF. Among them, the left atrial diameter was larger compared to that achieved in sinus rhythm (SR). The mRNA and protein expression of MMP-2 was significantly increased in recurrent AF patients, while its specific inhibitor did not show a significant difference (p > 0.05). The CVF of type I collagen increased significantly in the recurrent AF patients compared to SR patients (18.16 ± 3.22 vs. 11.66 ± 3.38, p < 0.001), whereas the CVF of type III collagen showed no significant difference (8.33 ± 3.44 vs. 9.55 ± 3.67, p > 0.05). CONCLUSION This study suggests that the overexpression of MMP-2 is associated with CVF-I in the left atrial appendage which potentially leads to the recurrence of AF following a radiofrequency modified maze procedure in patients with rheumatic valve disease.
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Affiliation(s)
- Xin Wang
- Department of Cardiovascular Surgery, Cardiovascular Institute and Fuwai Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
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