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Bayer JD, Sobota V, Bear LR, Haïssaguerre M, Vigmond EJ. A His bundle pacing protocol for suppressing ventricular arrhythmia maintenance and improving defibrillation efficacy. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2024; 253:108239. [PMID: 38823116 DOI: 10.1016/j.cmpb.2024.108239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 05/18/2024] [Accepted: 05/21/2024] [Indexed: 06/03/2024]
Abstract
BACKGROUND The excitable gap (EG), defined as the excitable tissue between two subsequent wavefronts of depolarization, is critical for maintaining reentry that underlies deadly ventricular arrhythmias. EG in the His-Purkinje Network (HPN) plays an important role in the maintenance of electrical wave reentry that underlies these arrhythmias. OBJECTIVE To determine if rapid His bundle pacing (HBP) during reentry reduces the amount of EG in the HPN and ventricular myocardium to suppress reentry maintenance and/or improve defibrillation efficacy. METHODS In a virtual human biventricular model, reentry was initiated with rapid line pacing followed by HBP delivered for 3, 6, or 9 s at pacing cycle lengths (PCLs) ranging from 10 to 300 ms (n=30). EG was calculated independently for the HPN and myocardium over each PCL. Defibrillation efficacy was assessed for each PCL by stimulating myocardial surface EG with delays ranging from 0.25 to 9 s (increments of 0.25 s, n=36) after the start of HBP. Defibrillation was successful if reentry terminated within 1 s after EG stimulation. This defibrillation protocol was repeated without HBP. To test the approach under different pathological conditions, all protocols were repeated in the model with right (RBBB) or left (LBBB) bundle branch block. RESULTS Compared to without pacing, HBP for >3 seconds reduced average EG in the HPN and myocardium across a broad range of PCLs for the default, RBBB, and LBBB models. HBP >6 seconds terminated reentrant arrhythmia by converting HPN activation to a sinus rhythm behavior in the default (6/30 PCLs) and RBBB (7/30 PCLs) models. Myocardial EG stimulation during HBP increased the number of successful defibrillation attempts by 3%-19% for 30/30 PCLs in the default model, 3%-6% for 14/30 PCLs in the RBBB model, and 3%-11% for 27/30 PCLs in the LBBB model. CONCLUSION HBP can reduce the amount of excitable gap and suppress reentry maintenance in the HPN and myocardium. HBP can also improve the efficacy of low-energy defibrillation approaches targeting excitable myocardium. HBP during reentrant arrhythmias is a promising anti-arrhythmic and defibrillation strategy.
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Affiliation(s)
- Jason D Bayer
- IHU Liryc, Electrophysiology and Heart Modeling Institute, fondation Bordeaux Université, 33600, Pessac-Bordeaux, France; University of Bordeaux, Institut de Mathématiques de Bordeaux, UMR 5251, 33400, Talence, France.
| | - Vladimír Sobota
- IHU Liryc, Electrophysiology and Heart Modeling Institute, fondation Bordeaux Université, 33600, Pessac-Bordeaux, France; University of Bordeaux, Institut de Mathématiques de Bordeaux, UMR 5251, 33400, Talence, France
| | - Laura R Bear
- IHU Liryc, Electrophysiology and Heart Modeling Institute, fondation Bordeaux Université, 33600, Pessac-Bordeaux, France
| | - Michel Haïssaguerre
- IHU Liryc, Electrophysiology and Heart Modeling Institute, fondation Bordeaux Université, 33600, Pessac-Bordeaux, France; Haut-Lévêque Cardiology Hospital, University Hospital Center (CHU) of Bordeaux, Pessac, France
| | - Edward J Vigmond
- IHU Liryc, Electrophysiology and Heart Modeling Institute, fondation Bordeaux Université, 33600, Pessac-Bordeaux, France; University of Bordeaux, Institut de Mathématiques de Bordeaux, UMR 5251, 33400, Talence, France
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2
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Trayanova NA, Lyon A, Shade J, Heijman J. Computational modeling of cardiac electrophysiology and arrhythmogenesis: toward clinical translation. Physiol Rev 2024; 104:1265-1333. [PMID: 38153307 DOI: 10.1152/physrev.00017.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 12/19/2023] [Accepted: 12/21/2023] [Indexed: 12/29/2023] Open
Abstract
The complexity of cardiac electrophysiology, involving dynamic changes in numerous components across multiple spatial (from ion channel to organ) and temporal (from milliseconds to days) scales, makes an intuitive or empirical analysis of cardiac arrhythmogenesis challenging. Multiscale mechanistic computational models of cardiac electrophysiology provide precise control over individual parameters, and their reproducibility enables a thorough assessment of arrhythmia mechanisms. This review provides a comprehensive analysis of models of cardiac electrophysiology and arrhythmias, from the single cell to the organ level, and how they can be leveraged to better understand rhythm disorders in cardiac disease and to improve heart patient care. Key issues related to model development based on experimental data are discussed, and major families of human cardiomyocyte models and their applications are highlighted. An overview of organ-level computational modeling of cardiac electrophysiology and its clinical applications in personalized arrhythmia risk assessment and patient-specific therapy of atrial and ventricular arrhythmias is provided. The advancements presented here highlight how patient-specific computational models of the heart reconstructed from patient data have achieved success in predicting risk of sudden cardiac death and guiding optimal treatments of heart rhythm disorders. Finally, an outlook toward potential future advances, including the combination of mechanistic modeling and machine learning/artificial intelligence, is provided. As the field of cardiology is embarking on a journey toward precision medicine, personalized modeling of the heart is expected to become a key technology to guide pharmaceutical therapy, deployment of devices, and surgical interventions.
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Affiliation(s)
- Natalia A Trayanova
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, United States
- Alliance for Cardiovascular Diagnostic and Treatment Innovation, Johns Hopkins University, Baltimore, Maryland, United States
| | - Aurore Lyon
- Department of Biomedical Engineering, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands
- Division of Heart and Lungs, Department of Medical Physiology, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Julie Shade
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, United States
- Alliance for Cardiovascular Diagnostic and Treatment Innovation, Johns Hopkins University, Baltimore, Maryland, United States
| | - Jordi Heijman
- Department of Cardiology, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands
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3
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Hurley M, Kaur S, Walton R, Power A, Haïssaguerre M, Bernus O, Ward ML, White E. Endocardial role in arrhythmias induced by acute ventricular stretch and the involvement of Purkinje fibres, in isolated rat hearts. Curr Res Physiol 2023; 6:100098. [PMID: 36814643 PMCID: PMC9939534 DOI: 10.1016/j.crphys.2023.100098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 01/13/2023] [Accepted: 01/25/2023] [Indexed: 02/04/2023] Open
Abstract
Purkinje fibres (PFs) play an important role in some ventricular arrhythmias and acute ventricular stretch can evoke mechanically-induced arrhythmias. We tested whether PFs and specifically TRPM4 channels, play a role in these mechanically-induced arrhythmias. Pseudo-ECGs and left ventricular (LV) activation, measured by optical mapping, were recorded in isolated, Langendorff-perfused, rat hearts. The LV endocardial surface was irrigated with experimental agents, via an indwelling catheter. The number and period of ectopic activations was measured during LV lumen inflation via an indwelling fluid-filled balloon (100 μL added over 2 s, maintained for 38 s). Mechanically-induced arrhythmias occurred during balloon inflation: they were multifocal, maximal in the first 5 s and ceased within 20 s. Optical mapping revealed activation patterns indicating PF-mediated and ectopic focal sources. Irrigation of the LV lumen with Lugol solution (IK/I2) for 10s reduced ectopics by 93% (n = 16, P < 0.001); with ablation of endocardial PFs confirmed by histology. Five min irrigation of the LV lumen with 50 μM 9-Phenanthrol, a blocker of TRPM4 channels, reduced ectopics by 39% (n = 15, P < 0.01). Immunohistochemistry confirmed that TRPM4 was more abundant in PFs than myocardium. Our results show that the endocardial surface plays an important role in these mechanically-induced ectopic activations. Ectopic activation patterns indicate a participation of PFs in these arrhythmias, with a potential involvement of TRPM4 channels, shown by the reduction of arrhythmias by 9-Phenanthrol.
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Affiliation(s)
- Miriam Hurley
- School of Biomedical Sciences, University of Leeds, Leeds, UK
| | - Sarbjot Kaur
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Richard Walton
- Université Bordeaux, INSERM Centre de recherche Cardio-Thoracique de Bordeaux, Pessac, Bordeaux, France,IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation, Bordeaux Université, Pessac, Bordeaux, France
| | - Amelia Power
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Michel Haïssaguerre
- Université Bordeaux, INSERM Centre de recherche Cardio-Thoracique de Bordeaux, Pessac, Bordeaux, France,IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation, Bordeaux Université, Pessac, Bordeaux, France,Bordeaux University Hospital (CHU), Electrophysiology and Ablation Unit, Pessac, France
| | - Olivier Bernus
- Université Bordeaux, INSERM Centre de recherche Cardio-Thoracique de Bordeaux, Pessac, Bordeaux, France,IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation, Bordeaux Université, Pessac, Bordeaux, France
| | - Marie-Louise Ward
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Ed White
- School of Biomedical Sciences, University of Leeds, Leeds, UK,Corresponding author. Garstang Building, School of Biomedical Sciences, University of Leeds, LS29JT, Leeds, UK.
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4
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Ezzeddine FM, Ward RC, Asirvatham SJ, DeSimone CV. Mapping and ablation of ventricular fibrillation substrate. J Interv Card Electrophysiol 2023:10.1007/s10840-022-01454-z. [PMID: 36598715 DOI: 10.1007/s10840-022-01454-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 12/09/2022] [Indexed: 01/05/2023]
Abstract
Ventricular fibrillation (VF) is a life-threatening arrhythmia and a common cause of sudden cardiac death (SCD). A basic understanding of its mechanistic underpinning is crucial for enhancing our knowledge to develop innovative mapping and ablation techniques for this lethal rhythm. Significant advances in our understanding of VF have been made especially in the basic science and pre-clinical experimental realms. However, these studies have not yet translated into a robust clinical approach to identify and successfully ablate both the structural and functional substrate of VF. In this review, we aim to (1) provide a conceptual framework of VF and an overview of the data supporting the spatiotemporal dynamics of VF, (2) review experimental approaches to mapping VF to elucidate drivers and substrate for maintenance with a focus on the His-Purkinje system, (3) discuss current approaches using catheter ablation to treat VF, and (4) highlight current unknowns and gaps in the field where future work is necessary to transform the clinical landscape.
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Affiliation(s)
- Fatima M Ezzeddine
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Robert Charles Ward
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Samuel J Asirvatham
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Christopher V DeSimone
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.
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5
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Hurley M, Walton R, Vigmond EJ, Haïssaguerre M, Bernus O, White E. Attenuation of stretch-induced arrhythmias following chemical ablation of Purkinje fibres, in isolated rabbit hearts. Front Physiol 2023; 14:1154157. [PMID: 37089427 PMCID: PMC10115947 DOI: 10.3389/fphys.2023.1154157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 03/23/2023] [Indexed: 04/25/2023] Open
Abstract
Purkinje fibres (PFs) play an important role in some ventricular arrhythmias and acute ventricular stretch can evoke mechanically-induced arrhythmias. We tested whether Purkinje fibres, play a role in these arrhythmias. Pseudo-ECGs were recorded in isolated, Langendorff-perfused, rabbit hearts in which the left ventricular endocardial surface was also irrigated with Tyrode, via an indwelling catheter placed in the left ventricular lumen. The number and period of ectopic activations was measured during left ventricular lumen inflation via an indwelling fluid-filled balloon (500 μL added over 2 s and maintained for 15 s in total). Mechanically-induced arrhythmias occurred in 70% of balloon inflations: they were maximal in the first 5 s and ceased within 15 s. Brief, (10 s) irrigation of the left ventricular lumen with Lugol solution (IK/I2), via the indwelling catheter, reduced inflation-induced ectopics by 98% (p < 0.05). Ablation of endocardial PFs by Lugol was confirmed by Triphenyltetrazolium Chloride staining. Optical mapping revealed the left ventricular epicardial activation patterns of ectopics could have PF-mediated and focal sources. In silico modelling predicted ectopic sources originating in the endocardial region propagate to and through the Purkinje fibres network. Acute distention-induced ectopics are multi-focal, their attenuation by Lugol, their activation patterns and in silico modelling indicate a participation of Purkinje fibres in these arrhythmias.
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Affiliation(s)
- Miriam Hurley
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Richard Walton
- INSERM Centre de recherche Cardio-Thoracique de Bordeaux, Université Bordeaux, Pessac-Bordeaux, France
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation, Bordeaux Université, Pessac-Bordeaux, France
| | - Edward J. Vigmond
- INSERM Centre de recherche Cardio-Thoracique de Bordeaux, Université Bordeaux, Pessac-Bordeaux, France
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation, Bordeaux Université, Pessac-Bordeaux, France
| | - Michel Haïssaguerre
- INSERM Centre de recherche Cardio-Thoracique de Bordeaux, Université Bordeaux, Pessac-Bordeaux, France
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation, Bordeaux Université, Pessac-Bordeaux, France
- Electrophysiology and Ablation Unit, Bordeaux University Hospital (CHU), Pessac, France
| | - Olivier Bernus
- INSERM Centre de recherche Cardio-Thoracique de Bordeaux, Université Bordeaux, Pessac-Bordeaux, France
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation, Bordeaux Université, Pessac-Bordeaux, France
| | - Ed White
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
- *Correspondence: Ed White,
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6
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Jian K, Li C, Hancox JC, Zhang H. Pro-Arrhythmic Effects of Discontinuous Conduction at the Purkinje Fiber-Ventricle Junction Arising From Heart Failure-Induced Ionic Remodeling - Insights From Computational Modelling. Front Physiol 2022; 13:877428. [PMID: 35547576 PMCID: PMC9081695 DOI: 10.3389/fphys.2022.877428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 03/18/2022] [Indexed: 11/18/2022] Open
Abstract
Heart failure is associated with electrical remodeling of the electrical properties and kinetics of the ion channels and transporters that are responsible for cardiac action potentials. However, it is still unclear whether heart failure-induced ionic remodeling can affect the conduction of excitation waves at the Purkinje fiber-ventricle junction contributing to pro-arrhythmic effects of heart failure, as the complexity of the heart impedes a detailed experimental analysis. The aim of this study was to employ computational models to investigate the pro-arrhythmic effects of heart failure-induced ionic remodeling on the cardiac action potentials and excitation wave conduction at the Purkinje fiber-ventricle junction. Single cell models of canine Purkinje fiber and ventricular myocytes were developed for control and heart failure. These single cell models were then incorporated into one-dimensional strand and three-dimensional wedge models to investigate the effects of heart failure-induced remodeling on propagation of action potentials in Purkinje fiber and ventricular tissue and at the Purkinje fiber-ventricle junction. This revealed that heart failure-induced ionic remodeling of Purkinje fiber and ventricular tissue reduced conduction safety and increased tissue vulnerability to the genesis of the unidirectional conduction block. This was marked at the Purkinje fiber-ventricle junction, forming a potential substrate for the genesis of conduction failure that led to re-entry. This study provides new insights into proarrhythmic consequences of heart failure-induced ionic remodeling.
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Affiliation(s)
- Kun Jian
- Biological Physics Group, Department of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom
| | - Chen Li
- Biological Physics Group, Department of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom
| | - Jules C. Hancox
- Biological Physics Group, Department of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom
- School of Physiology, Pharmacology and Neuroscience, Medical Sciences Building, University Walk, Bristol, United Kingdom
| | - Henggui Zhang
- Biological Physics Group, Department of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
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7
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Ai X, Yu P, Peng L, Luo L, Liu J, Li S, Lai X, Luan F, Meng X. Berberine: A Review of its Pharmacokinetics Properties and Therapeutic Potentials in Diverse Vascular Diseases. Front Pharmacol 2022; 12:762654. [PMID: 35370628 PMCID: PMC8964367 DOI: 10.3389/fphar.2021.762654] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 10/20/2021] [Indexed: 12/11/2022] Open
Abstract
Traditional Chinese medicine plays a significant role in the treatment of various diseases and has attracted increasing attention for clinical applications. Vascular diseases affecting vasculature in the heart, cerebrovascular disease, atherosclerosis, and diabetic complications have compromised quality of life for affected individuals and increase the burden on health care services. Berberine, a naturally occurring isoquinoline alkaloid form Rhizoma coptidis, is widely used in China as a folk medicine for its antibacterial and anti-inflammatory properties. Promisingly, an increasing number of studies have identified several cellular and molecular targets for berberine, indicating its potential as an alternative therapeutic strategy for vascular diseases, as well as providing novel evidence that supports the therapeutic potential of berberine to combat vascular diseases. The purpose of this review is to comprehensively and systematically describe the evidence for berberine as a therapeutic agent in vascular diseases, including its pharmacological effects, molecular mechanisms, and pharmacokinetics. According to data published so far, berberine shows remarkable anti-inflammatory, antioxidant, antiapoptotic, and antiautophagic activity via the regulation of multiple signaling pathways, including AMP-activated protein kinase (AMPK), nuclear factor κB (NF-κB), mitogen-activated protein kinase silent information regulator 1 (SIRT-1), hypoxia-inducible factor 1α (HIF-1α), vascular endothelial growth factor phosphoinositide 3-kinase (PI3K), protein kinase B (Akt), janus kinase 2 (JAK-2), Ca2+ channels, and endoplasmic reticulum stress. Moreover, we discuss the existing limitations of berberine in the treatment of vascular diseases, and give corresponding measures. In addition, we propose some research perspectives and challenges, and provide a solid evidence base from which further studies can excavate novel effective drugs from Chinese medicine monomers.
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Affiliation(s)
- Xiaopeng Ai
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China.,Department of Pharmacy, Affiliated Hospital of North Sichuan Medical College, Nanchong, China
| | - Peiling Yu
- Department of Pharmacy, Affiliated Hospital of North Sichuan Medical College, Nanchong, China
| | - Lixia Peng
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Liuling Luo
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Jia Liu
- School of Ethnic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Shengqian Li
- Department of Pharmacy, Affiliated Hospital of North Sichuan Medical College, Nanchong, China
| | - Xianrong Lai
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China.,School of Ethnic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Fei Luan
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Xianli Meng
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China.,Innovative Institute of Chinese Medicine and Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
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8
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Rodriguez Padilla J, Petras A, Magat J, Bayer J, Bihan-Poudec Y, El-Hamrani D, Ramlugun G, Neic A, Augustin C, Vaillant F, Constantin M, Benoist D, Pourtau L, Dubes V, Rogier J, Labrousse L, Bernus O, Quesson B, Haissaguerre M, Gsell M, Plank G, Ozenne V, Vigmond E. Impact of Intraventricular Septal Fiber Orientation on Cardiac Electromechanical Function. Am J Physiol Heart Circ Physiol 2022; 322:H936-H952. [PMID: 35302879 PMCID: PMC9109800 DOI: 10.1152/ajpheart.00050.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cardiac fiber direction is an important factor determining the propagation of electrical activity, as well as the development of mechanical force. In this article, we imaged the ventricles of several species with special attention to the intraventricular septum to determine the functional consequences of septal fiber organization. First, we identified a dual-layer organization of the fiber orientation in the intraventricular septum of ex vivo sheep hearts using diffusion tensor imaging at high field MRI. To expand the scope of the results, we investigated the presence of a similar fiber organization in five mammalian species (rat, canine, pig, sheep, and human) and highlighted the continuity of the layer with the moderator band in large mammalian species. We implemented the measured septal fiber fields in three-dimensional electromechanical computer models to assess the impact of the fiber orientation. The downward fibers produced a diamond activation pattern superficially in the right ventricle. Electromechanically, there was very little change in pressure volume loops although the stress distribution was altered. In conclusion, we clarified that the right ventricular septum has a downwardly directed superficial layer in larger mammalian species, which can have modest effects on stress distribution. NEW & NOTEWORTHY A dual-layer organization of the fiber orientation in the intraventricular septum was identified in ex vivo hearts of large mammals. The RV septum has a downwardly directed superficial layer that is continuous with the moderator band. Electrically, it produced a diamond activation pattern. Electromechanically, little change in pressure volume loops were noticed but stress distribution was altered. Fiber distribution derived from diffusion tensor imaging should be considered for an accurate strain and stress analysis.
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Affiliation(s)
| | - Argyrios Petras
- Johann Radon Institute for Computational and Applied Mathematics (RICAM), Austrian Academy of Sciences, Linz, Austria
| | - Julie Magat
- Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac-Bordeaux, France.,Univ. Bordeaux, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France.,INSERM, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
| | - Jason Bayer
- Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac-Bordeaux, France.,Univ. Bordeaux, IMB, UMR 5251, Talence, France
| | - Yann Bihan-Poudec
- Centre de Neuroscience Cognitive, CNRS UMR 5229, Université Claude Bernard Lyon I, France
| | - Dounia El-Hamrani
- Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac-Bordeaux, France.,Univ. Bordeaux, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France.,INSERM, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
| | - Girish Ramlugun
- Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac-Bordeaux, France.,Univ. Bordeaux, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France.,INSERM, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
| | - Aurel Neic
- Gottfried Schatz Research Center, Division of Biophysics, Medical University of Graz, Graz, Austria
| | - Christoph Augustin
- Gottfried Schatz Research Center, Division of Biophysics, Medical University of Graz, Graz, Austria.,BioTechMed-Graz, Graz, Austria
| | - Fanny Vaillant
- Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac-Bordeaux, France.,Univ. Bordeaux, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France.,INSERM, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
| | - Marion Constantin
- Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac-Bordeaux, France.,Univ. Bordeaux, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France.,INSERM, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
| | - David Benoist
- Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac-Bordeaux, France.,Univ. Bordeaux, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France.,INSERM, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
| | - Line Pourtau
- Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac-Bordeaux, France.,Univ. Bordeaux, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France.,INSERM, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
| | - Virginie Dubes
- Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac-Bordeaux, France.,Univ. Bordeaux, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France.,INSERM, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
| | | | | | - Olivier Bernus
- Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac-Bordeaux, France.,Univ. Bordeaux, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France.,INSERM, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
| | - Bruno Quesson
- Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac-Bordeaux, France.,Univ. Bordeaux, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France.,INSERM, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
| | | | - Matthias Gsell
- Gottfried Schatz Research Center, Division of Biophysics, Medical University of Graz, Graz, Austria
| | - Gernot Plank
- Gottfried Schatz Research Center, Division of Biophysics, Medical University of Graz, Graz, Austria.,BioTechMed-Graz, Graz, Austria
| | - Valéry Ozenne
- Centre de Résonance Magnétique des Systèmes Biologiques, UMR 5536, CNRS/Université de Bordeaux, Bordeaux, France
| | - Edward Vigmond
- Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac-Bordeaux, France.,Univ. Bordeaux, IMB, UMR 5251, Talence, France
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Anderson RD, Massé S, Asta J, Lai PFH, Chakraborty P, Azam MA, Downar E, Nanthakumar K. Role of Purkinje-Muscle Junction in Early Ventricular Fibrillation in a Porcine Model: Beyond the Trigger Concept. Pacing Clin Electrophysiol 2022; 45:742-751. [PMID: 35067947 DOI: 10.1111/pace.14453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 01/01/2022] [Accepted: 01/14/2022] [Indexed: 11/28/2022]
Abstract
BACKGROUND The role of the Purkinje network in triggering ventricular fibrillation (VF) has been studied, however, its involvement after onset and in early maintenance of VF is controversial. AIM We studied the role of the Purkinje-muscle junctions (PMJ) on epicardial-endocardial activation gradients during early VF. METHODS In a healthy, porcine, beating-heart Langendorff model [control, n = 5; ablation, n = 5], simultaneous epicardial-endocardial dominant frequent mapping was used (224 unipolar electrograms) to calculate activation rate gradients during the onset and early phase of VF. Selective Purkinje ablation was performed using Lugol's solution, followed by VF re-induction and mapping and finally, histological evaluation. RESULTS Epicardial activation rates were faster than endocardial rates for both onset and early VF. After PMJ ablation, activation rates decreased epicardially and endocardially for both onset and early VF [Epi: 9.7±0.2 to 8.3±0.2 Hz (P<0.0001) and 10.9±0.4 to 8.8±0.3 Hz (P<0.0001), respectively; Endo: 8.2 ± 0.3 Hz to 7.4 ± 0.2 Hz (P<0.0001) and 7.0 ± 0.4 Hz to 6.6 ± 0.3 Hz (P = 0.0002), respectively]. In controls, epicardial-endocardial activation rate gradients during onset and early VF were 1.7±0.3 Hz and 4.5±0.4 Hz (P<0.001), respectively. After endocardial ablation of PMJs, these gradients were reduced to 0.9±0.3 Hz (onset VF, P<0.001) and to 2.2±0.3 Hz (early VF, P<0.001). Endocardial-epicardial Purkinje fibre arborization and selective Purkinje fibre extinction after only endocardial ablation (not with epicardial ablation) was confirmed on histological analysis. CONCLUSIONS Beyond the trigger paradigm, PMJs determine activation rate gradients during onset and during early maintenance of VF. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Robert D Anderson
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Canada
| | - Stéphane Massé
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Canada
| | - John Asta
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Canada
| | - Patrick F H Lai
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Canada
| | - Praloy Chakraborty
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Canada
| | - Mohammed Ali Azam
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Canada
| | - Eugene Downar
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Canada
| | - Kumaraswamy Nanthakumar
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Canada
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10
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The Purkinje network plays a major role in low-energy ventricular defibrillation. Comput Biol Med 2021; 141:105133. [PMID: 34954609 DOI: 10.1016/j.compbiomed.2021.105133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 12/10/2021] [Accepted: 12/10/2021] [Indexed: 11/20/2022]
Abstract
BACKGROUND During ventricular fibrillation (VF), targeting the excitable gap (EG) of reentry throughout the myocardium with low-energy surface stimulation shows promise for painless defibrillation. However, the Purkinje network may provide alternative pathways for reentry to evade termination. This study investigates the role of the Purkinje network in painless defibrillation. METHODS In a computational human biventricular model featuring a Purkinje network, VF was initiated with 4 Hz epicardial pacing. Defibrillation was attempted by stimulating myocardial surface EG with a low-energy 2 ms duration pulse at 2x stimulus capture, which was administered at coupling intervals incremented by 0.25 s between 0.25 and 5 s after VF initiation. Defibrillation was accomplished if reentry ceased ≤ 1 s after the defibrillation pulse. The protocol was repeated with the Purkinje network and myocardial surface EG stimulated simultaneously, and again after uncoupling the Purkinje network from the myocardium. RESULTS VF with the Purkinje network coupled and uncoupled had comparable dominant frequency in the left (3.81 ± 0.44 versus 3.77 ± 0.53 Hz) and right (3.80 ± 0.37 versus 3.76 ± 0.48 Hz) ventricles. When uncoupling the Purkinje network, myocardial surface EG stimulation terminated VF for all defibrillation pulses. When coupled, myocardial EG surface stimulation terminated VF for only 55% of the defibrillation pulses, but improved to 100% when stimulated simultaneously with Purkinje network EG. Defibrillation failures were attributed to EG evading stimulation in the Purkinje network. CONCLUSIONS Defibrillation that exclusively targets myocardium can fail due to accessory pathways in the Purkinje network that allow for reentrant activity to evade termination and maintain VF. Painless defibrillation strategies should be adapted to include the Purkinje network.
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11
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Analysis of vulnerability to reentry in acute myocardial ischemia using a realistic human heart model. Comput Biol Med 2021; 141:105038. [PMID: 34836624 DOI: 10.1016/j.compbiomed.2021.105038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 10/25/2021] [Accepted: 11/12/2021] [Indexed: 11/21/2022]
Abstract
Electrophysiological alterations of the myocardium caused by acute ischemia constitute a pro-arrhythmic substrate for the generation of potentially lethal arrhythmias. Experimental evidence has shown that the main components of acute ischemia that induce these electrophysiological alterations are hyperkalemia, hypoxia (or anoxia in complete artery occlusion), and acidosis. However, the influence of each ischemic component on the likelihood of reentry is not completely established. Moreover, the role of the His-Purkinje system (HPS) in the initiation and maintenance of arrhythmias is not completely understood. In the present work, we investigate how the three components of ischemia affect the vulnerable window (VW) for reentry using computational simulations. In addition, we analyze the role of the HPS on arrhythmogenesis. A 3D biventricular/torso human model that includes a realistic geometry of the central and border ischemic zones with one of the most electrophysiologically detailed model of ischemia to date, as well as a realistic cardiac conduction system, were used to assess the VW for reentry. Four scenarios of ischemic severity corresponding to different minutes after coronary artery occlusion were simulated. Our results suggest that ischemic severity plays an important role in the generation of reentries. Indeed, this is the first 3D simulation study to show that ventricular arrhythmias could be generated under moderate ischemic conditions, but not in mild and severe ischemia. Moreover, our results show that anoxia is the ischemic component with the most significant effect on the width of the VW. Thus, a change in the level of anoxia from moderate to severe leads to a greater increment in the VW (40 ms), in comparison with the increment of 20 ms and 35 ms produced by the individual change in the level of hyperkalemia and acidosis, respectively. Finally, the HPS was a necessary element for the generation of approximately 17% of reentries obtained. The retrograde conduction from the myocardium to HPS in the ischemic region, conduction blocks in discrete sections of the HPS, and the degree of ischemia affecting Purkinje cells, are suggested as mechanisms that favor the generation of ventricular arrhythmias.
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12
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Odening KE, Gomez AM, Dobrev D, Fabritz L, Heinzel FR, Mangoni ME, Molina CE, Sacconi L, Smith G, Stengl M, Thomas D, Zaza A, Remme CA, Heijman J. ESC working group on cardiac cellular electrophysiology position paper: relevance, opportunities, and limitations of experimental models for cardiac electrophysiology research. Europace 2021; 23:1795-1814. [PMID: 34313298 DOI: 10.1093/europace/euab142] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 05/19/2021] [Indexed: 12/19/2022] Open
Abstract
Cardiac arrhythmias are a major cause of death and disability. A large number of experimental cell and animal models have been developed to study arrhythmogenic diseases. These models have provided important insights into the underlying arrhythmia mechanisms and translational options for their therapeutic management. This position paper from the ESC Working Group on Cardiac Cellular Electrophysiology provides an overview of (i) currently available in vitro, ex vivo, and in vivo electrophysiological research methodologies, (ii) the most commonly used experimental (cellular and animal) models for cardiac arrhythmias including relevant species differences, (iii) the use of human cardiac tissue, induced pluripotent stem cell (hiPSC)-derived and in silico models to study cardiac arrhythmias, and (iv) the availability, relevance, limitations, and opportunities of these cellular and animal models to recapitulate specific acquired and inherited arrhythmogenic diseases, including atrial fibrillation, heart failure, cardiomyopathy, myocarditis, sinus node, and conduction disorders and channelopathies. By promoting a better understanding of these models and their limitations, this position paper aims to improve the quality of basic research in cardiac electrophysiology, with the ultimate goal to facilitate the clinical translation and application of basic electrophysiological research findings on arrhythmia mechanisms and therapies.
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Affiliation(s)
- Katja E Odening
- Translational Cardiology, Department of Cardiology, Inselspital, Bern University Hospital, Bern, Switzerland.,Institute of Physiology, University of Bern, Bern, Switzerland
| | - Ana-Maria Gomez
- Signaling and cardiovascular pathophysiology-UMR-S 1180, Inserm, Université Paris-Saclay, 92296 Châtenay-Malabry, France
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Essen, Germany
| | - Larissa Fabritz
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, UK.,Department of Cardiology, University Hospital Birmingham NHS Trust, Birmingham, UK
| | - Frank R Heinzel
- Department of Internal Medicine and Cardiology, Charité - Universitätsmedizin Berlin, Campus Virchow-Klinikum, Berlin, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site, Berlin, Germany
| | - Matteo E Mangoni
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Cristina E Molina
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,German Centre for Cardiovascular Research (DZHK), Partner Site, Hamburg/Kiel/Lübeck, Germany
| | - Leonardo Sacconi
- National Institute of Optics and European Laboratory for Non Linear Spectroscopy, Italy.,Institute for Experimental Cardiovascular Medicine, University Freiburg, Germany
| | - Godfrey Smith
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, UK
| | - Milan Stengl
- Department of Physiology, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Dierk Thomas
- Department of Cardiology, University Hospital Heidelberg, Heidelberg, Germany; Heidelberg Center for Heart Rhythm Disorders (HCR), University Hospital Heidelberg, Heidelberg, Germany.,German Centre for Cardiovascular Research (DZHK), Partner Site, Heidelberg/Mannheim, Germany
| | - Antonio Zaza
- Department of Biotechnology and Bioscience, University of Milano-Bicocca, Milano, Italy
| | - Carol Ann Remme
- Department of Experimental Cardiology, Amsterdam UMC, location AMC, Amsterdam, The Netherlands
| | - Jordi Heijman
- Department of Cardiology, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands
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Olejnickova V, Kocka M, Kvasilova A, Kolesova H, Dziacky A, Gidor T, Gidor L, Sankova B, Gregorovicova M, Gourdie RG, Sedmera D. Gap Junctional Communication via Connexin43 between Purkinje Fibers and Working Myocytes Explains the Epicardial Activation Pattern in the Postnatal Mouse Left Ventricle. Int J Mol Sci 2021; 22:2475. [PMID: 33804428 PMCID: PMC7957598 DOI: 10.3390/ijms22052475] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 02/19/2021] [Accepted: 02/25/2021] [Indexed: 12/31/2022] Open
Abstract
The mammalian ventricular myocardium forms a functional syncytium due to flow of electrical current mediated in part by gap junctions localized within intercalated disks. The connexin (Cx) subunit of gap junctions have direct and indirect roles in conduction of electrical impulse from the cardiac pacemaker via the cardiac conduction system (CCS) to working myocytes. Cx43 is the dominant isoform in these channels. We have studied the distribution of Cx43 junctions between the CCS and working myocytes in a transgenic mouse model, which had the His-Purkinje portion of the CCS labeled with green fluorescence protein. The highest number of such connections was found in a region about one-third of ventricular length above the apex, and it correlated with the peak proportion of Purkinje fibers (PFs) to the ventricular myocardium. At this location, on the septal surface of the left ventricle, the insulated left bundle branch split into the uninsulated network of PFs that continued to the free wall anteriorly and posteriorly. The second peak of PF abundance was present in the ventricular apex. Epicardial activation maps correspondingly placed the site of the first activation in the apical region, while some hearts presented more highly located breakthrough sites. Taken together, these results increase our understanding of the physiological pattern of ventricular activation and its morphological underpinning through detailed CCS anatomy and distribution of its gap junctional coupling to the working myocardium.
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Affiliation(s)
- Veronika Olejnickova
- Institute of Anatomy, First Faculty of Medicine, Charles University, 128 00 Prague, Czech Republic; (V.O.); (M.K.); (A.K.); (H.K.); (A.D.); (T.G.); (L.G.); (B.S.); (M.G.)
- Institute of Physiology, CAS, 142 20 Prague, Czech Republic
| | - Matej Kocka
- Institute of Anatomy, First Faculty of Medicine, Charles University, 128 00 Prague, Czech Republic; (V.O.); (M.K.); (A.K.); (H.K.); (A.D.); (T.G.); (L.G.); (B.S.); (M.G.)
| | - Alena Kvasilova
- Institute of Anatomy, First Faculty of Medicine, Charles University, 128 00 Prague, Czech Republic; (V.O.); (M.K.); (A.K.); (H.K.); (A.D.); (T.G.); (L.G.); (B.S.); (M.G.)
| | - Hana Kolesova
- Institute of Anatomy, First Faculty of Medicine, Charles University, 128 00 Prague, Czech Republic; (V.O.); (M.K.); (A.K.); (H.K.); (A.D.); (T.G.); (L.G.); (B.S.); (M.G.)
- Institute of Physiology, CAS, 142 20 Prague, Czech Republic
| | - Adam Dziacky
- Institute of Anatomy, First Faculty of Medicine, Charles University, 128 00 Prague, Czech Republic; (V.O.); (M.K.); (A.K.); (H.K.); (A.D.); (T.G.); (L.G.); (B.S.); (M.G.)
- Department of Pediatric Cardiology, Motol University Hospital, 150 06 Prague, Czech Republic
| | - Tom Gidor
- Institute of Anatomy, First Faculty of Medicine, Charles University, 128 00 Prague, Czech Republic; (V.O.); (M.K.); (A.K.); (H.K.); (A.D.); (T.G.); (L.G.); (B.S.); (M.G.)
| | - Lihi Gidor
- Institute of Anatomy, First Faculty of Medicine, Charles University, 128 00 Prague, Czech Republic; (V.O.); (M.K.); (A.K.); (H.K.); (A.D.); (T.G.); (L.G.); (B.S.); (M.G.)
| | - Barbora Sankova
- Institute of Anatomy, First Faculty of Medicine, Charles University, 128 00 Prague, Czech Republic; (V.O.); (M.K.); (A.K.); (H.K.); (A.D.); (T.G.); (L.G.); (B.S.); (M.G.)
| | - Martina Gregorovicova
- Institute of Anatomy, First Faculty of Medicine, Charles University, 128 00 Prague, Czech Republic; (V.O.); (M.K.); (A.K.); (H.K.); (A.D.); (T.G.); (L.G.); (B.S.); (M.G.)
- Institute of Physiology, CAS, 142 20 Prague, Czech Republic
| | - Robert G. Gourdie
- Fralin Biomedical Research Institute, Virginia Tech, Roanoke, VA 24016, USA;
| | - David Sedmera
- Institute of Anatomy, First Faculty of Medicine, Charles University, 128 00 Prague, Czech Republic; (V.O.); (M.K.); (A.K.); (H.K.); (A.D.); (T.G.); (L.G.); (B.S.); (M.G.)
- Institute of Physiology, CAS, 142 20 Prague, Czech Republic
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14
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Varró A, Tomek J, Nagy N, Virág L, Passini E, Rodriguez B, Baczkó I. Cardiac transmembrane ion channels and action potentials: cellular physiology and arrhythmogenic behavior. Physiol Rev 2020; 101:1083-1176. [PMID: 33118864 DOI: 10.1152/physrev.00024.2019] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Cardiac arrhythmias are among the leading causes of mortality. They often arise from alterations in the electrophysiological properties of cardiac cells and their underlying ionic mechanisms. It is therefore critical to further unravel the pathophysiology of the ionic basis of human cardiac electrophysiology in health and disease. In the first part of this review, current knowledge on the differences in ion channel expression and properties of the ionic processes that determine the morphology and properties of cardiac action potentials and calcium dynamics from cardiomyocytes in different regions of the heart are described. Then the cellular mechanisms promoting arrhythmias in congenital or acquired conditions of ion channel function (electrical remodeling) are discussed. The focus is on human-relevant findings obtained with clinical, experimental, and computational studies, given that interspecies differences make the extrapolation from animal experiments to human clinical settings difficult. Deepening the understanding of the diverse pathophysiology of human cellular electrophysiology will help in developing novel and effective antiarrhythmic strategies for specific subpopulations and disease conditions.
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Affiliation(s)
- András Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - Jakub Tomek
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Norbert Nagy
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - László Virág
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Elisa Passini
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Blanca Rodriguez
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
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15
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Árpádffy-Lovas T, Husti Z, Baczkó I, Varró A, Virág L. Different effects of amiodarone and dofetilide on the dispersion of repolarization between well-coupled ventricular and Purkinje fibers 1. Can J Physiol Pharmacol 2020; 99:48-55. [PMID: 32692935 DOI: 10.1139/cjpp-2020-0234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Increased transmural dispersion of repolarization is an established contributing factor to ventricular tachyarrhythmias. In this study, we evaluated the effect of chronic amiodarone treatment and acute administration of dofetilide in canine cardiac preparations containing electrotonically coupled Purkinje fibers (PFs) and ventricular muscle (VM) and compared the effects to those in uncoupled PF and VM preparations using the conventional microelectrode technique. Dispersion between PFs and VM was inferred from the difference in the respective action potential durations (APDs). In coupled preparations, amiodarone decreased the difference in APDs between PFs and VM, thus decreasing dispersion. In the same preparations, dofetilide increased the dispersion by causing a more pronounced prolongation in PFs. This prolongation was even more emphasized in uncoupled PF preparations, while the effect in VM was the same. In uncoupled preparations, amiodarone elicited no change on the difference in APDs. In conclusion, amiodarone decreased the dispersion between PFs and VM, while dofetilide increased it. The measured difference in APD between cardiac regions may be the affected by electrotonic coupling; thus, studying PFs and VM separately may lead to an over- or underestimation of dispersion.
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Affiliation(s)
- Tamás Árpádffy-Lovas
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Zoltán Husti
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary.,MTA-SZTE Research Group of Cardiovascular Pharmacology, Szeged, Hungary
| | - András Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary.,MTA-SZTE Research Group of Cardiovascular Pharmacology, Szeged, Hungary
| | - László Virág
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary.,MTA-SZTE Research Group of Cardiovascular Pharmacology, Szeged, Hungary
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