1
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O’Hara RP, Meijborg VM, Jelvehgaran P, van der Waal J, Boink GJ, Trayanova NA, Coronel R, Boukens BJ. Site-specific prolongation of repolarization prevents postmyocardial infarction tachycardia. Heart Rhythm O2 2023; 4:466-468. [PMID: 37520014 PMCID: PMC10373146 DOI: 10.1016/j.hroo.2023.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/01/2023] Open
Affiliation(s)
- Ryan P. O’Hara
- Institute for Computational Medicine and Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland
| | - Veronique M.F. Meijborg
- Heart Center, Department of Clinical and Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Pouya Jelvehgaran
- Heart Center, Department of Clinical and Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Jeanne van der Waal
- Heart Center, Department of Clinical and Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Gerard J.J. Boink
- Heart Center, Department of Clinical and Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Natalia A. Trayanova
- Institute for Computational Medicine and Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland
| | - Ruben Coronel
- Heart Center, Department of Clinical and Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
- Fondation Bordeaux Université, Inserm, U1045 and Université de Bordeaux, Bordeaux, France
| | - Bastiaan J. Boukens
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands
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2
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Elbrønd VS, Thomsen MB, Isaksen JL, Lunde ED, Vincenti S, Wang T, Tranum-Jensen J, Calloe K. Intramural Purkinje fibers facilitate rapid ventricular activation in the equine heart. Acta Physiol (Oxf) 2023; 237:e13925. [PMID: 36606541 DOI: 10.1111/apha.13925] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 12/11/2022] [Accepted: 01/03/2023] [Indexed: 01/07/2023]
Abstract
BACKGROUND The Purkinje fibers convey the electrical impulses at much higher speed than the working myocardial cells. Thus, the distribution of the Purkinje network is of paramount importance for the timing and coordination of ventricular activation. The Purkinje fibers are found in the subendocardium of all species of mammals, but some mammals also possess an intramural Purkinje fiber network that provides for relatively instantaneous, burst-like activation of the entire ventricular wall, and gives rise to an rS configuration in lead II of the ECG. AIM To relate the topography of the horse heart and the distribution and histology of the conduction system to the pattern of ventricular activation as a mechanism for the unique electrical axis of the equine heart. METHODS The morphology and distribution of the cardiac conduction system was determined by histochemistry. The electrical activity was measured using ECG in the Einthoven and orthogonal configuration. RESULTS The long axis of the equine heart is close to vertical. Outside the nodal regions the conduction system consisted of Purkinje fibers connected by connexin 43 and long, slender parallel running transitional cells. The Purkinje fiber network extended deep into the ventricular walls. ECGs recorded in an orthogonal configuration revealed a mean electrical axis pointing in a cranial-to-left direction indicating ventricular activation in an apex-to-base direction. CONCLUSION The direction of the mean electrical axis in the equine heart is determined by the architecture of the intramural Purkinje network, rather than being a reflection of ventricular mass.
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Affiliation(s)
- Vibeke S Elbrønd
- Section for Pathobiological Sciences, Department of Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Morten B Thomsen
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jonas L Isaksen
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ester D Lunde
- Section for Pathobiological Sciences, Department of Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Stefano Vincenti
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Tobias Wang
- Section for Zoophysiology, Department of Biology, Aarhus University, Aarhus C, Denmark
| | - Jørgen Tranum-Jensen
- Department of Cellular and Molecular Medicine, The Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Kirstine Calloe
- Section for Pathobiological Sciences, Department of Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg C, Denmark
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3
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Stoks J, Bear LR, Vijgen J, Dendale P, Peeters R, Volders PGA, Cluitmans MJM. Understanding repolarization in the intracardiac unipolar electrogram: A long-lasting controversy revisited. Front Physiol 2023; 14:1158003. [PMID: 37089414 PMCID: PMC10119409 DOI: 10.3389/fphys.2023.1158003] [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: 02/03/2023] [Accepted: 03/24/2023] [Indexed: 04/25/2023] Open
Abstract
Background: The optimal way to determine repolarization time (RT) from the intracardiac unipolar electrogram (UEG) has been a topic of debate for decades. RT is typically determined by either the Wyatt method or the "alternative method," which both consider UEG T-wave slope, but differently. Objective: To determine the optimal method to measure RT on the UEG. Methods: Seven pig hearts surrounded by an epicardial sock with 100 electrodes were Langendorff-perfused with selective cannulation of the left anterior descending (LAD) coronary artery and submersed in a torso-shaped tank containing 256 electrodes on the torso surface. Repolarization was prolonged in the non-LAD-regions by infusing dofetilide and shortened in the LAD-region using pinacidil. RT was determined by the Wyatt (tWyatt) and alternative (tAlt) methods, in both invasive (recorded with epicardial electrodes) and in non-invasive UEGs (reconstructed with electrocardiographic imaging). tWyatt and tAlt were compared to local effective refractory period (ERP). Results: With contact mapping, mean absolute error (MAE) of tWyatt and tAlt vs. ERP were 21 ms and 71 ms, respectively. Positive T-waves typically had an earlier ERP than negative T-waves, in line with theory. tWyatt -but not tAlt-shortened by local infusion of pinacidil. Similar results were found for the non-invasive UEGs (MAE of tWyatt and tAlt vs. ERP were 30 ms and 92 ms, respectively). Conclusion: The Wyatt method is the most accurate to determine RT from (non) invasive UEGs, based on novel and historical analyses. Using it to determine RT could unify and facilitate repolarization assessment and amplify its role in cardiac electrophysiology.
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Affiliation(s)
- Job Stoks
- Department of Cardiology, CARIM, Maastricht University Medical Center+, Maastricht, Netherlands
- Department of Advanced Computing Sciences, Maastricht University, Maastricht, Netherlands
- Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium
| | - Laura R. Bear
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France
| | - Johan Vijgen
- Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium
| | - Paul Dendale
- Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium
| | - Ralf Peeters
- Department of Advanced Computing Sciences, Maastricht University, Maastricht, Netherlands
| | - Paul G. A. Volders
- Department of Cardiology, CARIM, Maastricht University Medical Center+, Maastricht, Netherlands
| | - Matthijs J. M. Cluitmans
- Department of Cardiology, CARIM, Maastricht University Medical Center+, Maastricht, Netherlands
- *Correspondence: Matthijs J. M. Cluitmans,
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4
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Taggart P, Pueyo E, Duijvenboden SV, Porter B, Bishop M, Sampedro-Puente DA, Orini M, Hanson B, Rinaldi CA, Gill JS, Lambiase P. Emerging evidence for a mechanistic link between low-frequency oscillation of ventricular repolarization measured from the electrocardiogram T-wave vector and arrhythmia. Europace 2021; 23:1350-1358. [PMID: 33880542 PMCID: PMC8427352 DOI: 10.1093/europace/euab009] [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: 09/11/2020] [Indexed: 11/17/2022] Open
Abstract
Strong recent clinical evidence links the presence of prominent oscillations of ventricular repolarization in the low-frequency range (0.04–0.15 Hz) to the incidence of ventricular arrhythmia and sudden death in post-MI patients and patients with ischaemic and non-ischaemic cardiomyopathy. It has been proposed that these oscillations reflect oscillations of ventricular action potential duration at the sympathetic nerve frequency. Here we review emerging evidence to support that contention and provide insight into possible underlying mechanisms for this association.
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Affiliation(s)
- Peter Taggart
- Department of Cardiovascular Sciences, University College London, London, UK
| | - Esther Pueyo
- BSICOS Group, 13A, 11S, Aragon, University of Zaragoza, Spain.,CIBER-BBN, Zaragoza, Spain
| | | | - Bradley Porter
- Department of Imaging Sciences and Biomedical Engineering, KCL, London, UK
| | - Martin Bishop
- Department of Imaging Sciences and Biomedical Engineering, KCL, London, UK
| | | | - M Orini
- Department of Cardiovascular Sciences, University College London, London, UK
| | - B Hanson
- UCL Mechanical Engineering, University College London, London, UK
| | | | | | - Pier Lambiase
- Department of Cardiovascular Sciences, University College London, London, UK
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5
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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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6
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Blok M, Boukens BJ. Mechanisms of Arrhythmias in the Brugada Syndrome. Int J Mol Sci 2020; 21:ijms21197051. [PMID: 32992720 PMCID: PMC7582368 DOI: 10.3390/ijms21197051] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 09/15/2020] [Accepted: 09/21/2020] [Indexed: 12/13/2022] Open
Abstract
Arrhythmias in Brugada syndrome patients originate in the right ventricular outflow tract (RVOT). Over the past few decades, the characterization of the unique anatomy and electrophysiology of the RVOT has revealed the arrhythmogenic nature of this region. However, the mechanisms that drive arrhythmias in Brugada syndrome patients remain debated as well as the exact site of their occurrence in the RVOT. Identifying the site of origin and mechanism of Brugada syndrome would greatly benefit the development of mechanism-driven treatment strategies.
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Affiliation(s)
- Michiel Blok
- Department of Medical Biology, Amsterdam University Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
- Department of Experimental Cardiology, Amsterdam University Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Bastiaan J. Boukens
- Department of Medical Biology, Amsterdam University Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
- Department of Experimental Cardiology, Amsterdam University Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
- Correspondence: ; Tel.: +31-(0)20-566-4659
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7
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Ang R, Marina N. Low-Frequency Oscillations in Cardiac Sympathetic Neuronal Activity. Front Physiol 2020; 11:236. [PMID: 32256390 PMCID: PMC7093552 DOI: 10.3389/fphys.2020.00236] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 03/02/2020] [Indexed: 12/25/2022] Open
Abstract
Sudden cardiac death caused by ventricular arrhythmias is among the leading causes of mortality, with approximately half of all deaths attributed to heart disease worldwide. Periodic repolarization dynamics (PRD) is a novel marker of repolarization instability and strong predictor of death in patients post-myocardial infarction that is believed to occur in association with low-frequency oscillations in sympathetic nerve activity. However, this hypothesis is based on associations of PRD with indices of sympathetic activity that are not directly linked to cardiac function, such as muscle vasoconstrictor activity and the variability of cardiovascular autospectra. In this review article, we critically evaluate existing scientific evidence obtained primarily in experimental animal models, with the aim of identifying the neuronal networks responsible for the generation of low-frequency sympathetic rhythms along the neurocardiac axis. We discuss the functional significance of rhythmic sympathetic activity on neurotransmission efficacy and explore its role in the pathogenesis of ventricular repolarization instability. Most importantly, we discuss important gaps in our knowledge that require further investigation in order to confirm the hypothesis that low frequency cardiac sympathetic oscillations play a causative role in the generation of PRD.
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Affiliation(s)
- Richard Ang
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Nephtali Marina
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom.,Division of Medicine, University College London, London, United Kingdom
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8
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Wang S, Rodríguez-Mañero M, Ibarra-Cortez SH, Kreidieh B, Valderrábano L, Hemam M, Tavares L, Blanco E, Valderrábano M. NS5806 Induces Electromechanically Discordant Alternans and Arrhythmogenic Voltage-Calcium Dynamics in the Isolated Intact Rabbit Heart. Front Physiol 2020; 10:1509. [PMID: 31920713 PMCID: PMC6933003 DOI: 10.3389/fphys.2019.01509] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 11/29/2019] [Indexed: 12/19/2022] Open
Abstract
Background: NS5806 activates the transient outward potassium current I to, and has been claimed to reproduce Brugada Syndrome (BrS) in ventricular wedge preparations. I to modulates excitation-contraction coupling, which is critical in alternans dynamics. We explored NS5806-arrhythmogenic effects in the intact whole heart and its impact on alternans. Methods: Langendorff-perfused rabbit hearts (n = 20) underwent optical AP and Ca mapping during pacing at decremental cycle lengths (CL). Spontaneous arrhythmias and pacing-induced alternans was characterized at baseline (BL), after perfusing with NS5806, before and after adding verapamil (VP), and SEA0400 (SEA, n = 5 each), to modulate Ca-current and Na-Ca exchange, the main AP-Ca coupling mechanisms. Results: NS5806 induced BrS-like ECG features in 6 out of 20 hearts. NS5806 prolonged steady-state (3 Hz) action potential duration (APD) by 16.8%, Ca decay constant by 34%, and decreased conduction velocity (CV) by 52.6%. After NS5806 infusion, spontaneous ventricular ectopy (VE) and AP/Ca alternans occurred. Pacing-induced alternans during NS5806 infusion occurred at longer CL and were AP/Ca discordant from its onset. Spatially discordant alternans after NS5806 infusion had non-propagation-driven nodal line distribution. No spontaneous phase-2 reentry occurred. Under NS5806 + VP, alternans became AP/Ca concordant and only induced in two out of five; NS5806 + SEA did not affect alternans but suppressed spontaneous ectopy. Conclusions: NS5806 disrupts AP-Ca coupling and leads to Ca-driven, AP/Ca-discordant alternans and VE. Despite BrS-like ECG features, no spontaneous sustained arrhythmias or phase-2 reentry occurred. NS5806 does not fully reproduce BrS in the intact rabbit heart.
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Affiliation(s)
- Sufen Wang
- Department of Cardiology, Houston Methodist DeBakey Heart and Vascular Center, Houston Methodist Hospital, Houston Methodist Research Institute, Houston, TX, United States
| | - Moisés Rodríguez-Mañero
- Cardiology Department, Complejo Hospital Universitario de Santiago, Santiago de Compostela, Spain.,Instituto de Investigación Sanitaria (IDIS), Universidad de Santiago de Compostela, Santiago de Compostela, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV CB16/11/00226 - CB16/11/00420), Madrid, Spain
| | - Sergio H Ibarra-Cortez
- Department of Cardiology, Houston Methodist DeBakey Heart and Vascular Center, Houston Methodist Hospital, Houston Methodist Research Institute, Houston, TX, United States
| | - Bahij Kreidieh
- Department of Cardiology, Houston Methodist DeBakey Heart and Vascular Center, Houston Methodist Hospital, Houston Methodist Research Institute, Houston, TX, United States
| | - Laura Valderrábano
- Department of Cardiology, Houston Methodist DeBakey Heart and Vascular Center, Houston Methodist Hospital, Houston Methodist Research Institute, Houston, TX, United States
| | - Majd Hemam
- Department of Cardiology, Houston Methodist DeBakey Heart and Vascular Center, Houston Methodist Hospital, Houston Methodist Research Institute, Houston, TX, United States
| | - Liliana Tavares
- Department of Cardiology, Houston Methodist DeBakey Heart and Vascular Center, Houston Methodist Hospital, Houston Methodist Research Institute, Houston, TX, United States
| | - Elvin Blanco
- Department of Cardiology, Houston Methodist DeBakey Heart and Vascular Center, Houston Methodist Hospital, Houston Methodist Research Institute, Houston, TX, United States.,Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX, United States
| | - Miguel Valderrábano
- Department of Cardiology, Houston Methodist DeBakey Heart and Vascular Center, Houston Methodist Hospital, Houston Methodist Research Institute, Houston, TX, United States
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9
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Calloe K. Doctoral Dissertation: The transient outward potassium current in healthy and diseased hearts. Acta Physiol (Oxf) 2019; 225 Suppl 717:e13225. [PMID: 30628199 DOI: 10.1111/apha.13225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Revised: 11/20/2018] [Accepted: 11/21/2018] [Indexed: 12/13/2022]
Affiliation(s)
- Kirstine Calloe
- Section for Anatomy; Biochemistry and Physiology; Department for Veterinary and Animal Sciences; Faculty of Health and Medical Sciences; University of Copenhagen; Frederiksberg C Denmark
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10
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Janusek D, Svehlikova J, Zelinka J, Weigl W, Zaczek R, Opolski G, Tysler M, Maniewski R. The roles of mid-myocardial and epicardial cells in T-wave alternans development: a simulation study. Biomed Eng Online 2018; 17:57. [PMID: 29739399 PMCID: PMC5941457 DOI: 10.1186/s12938-018-0492-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 04/28/2018] [Indexed: 01/31/2023] Open
Abstract
Background The occurrence of T-wave alternans in electrocardiographic signals was recently linked to susceptibility to ventricular arrhythmias and sudden cardiac death. Thus, by detecting and comprehending the origins of T-wave alternans, it might be possible to prevent such events. Results Here, we simulated T-wave alternans in a computer-generated human heart model by modulating the action potential duration and amplitude during the first part of the repolarization phase. We hypothesized that changes in the intracardiac alternans patterns of action potential properties would differentially influence T-wave alternans measurements at the body surface. Specifically, changes were simulated globally in the whole left and right ventricles to simulate concordant T-wave alternans, and locally in selected regions to simulate discordant and regional discordant, hereinafter referred to as “regional”, T-wave alternans. Body surface potential maps and 12-lead electrocardiographic signals were then computed. In depth discrimination, the influence of epicardial layers on T-wave alternans development was significantly higher than that of mid-myocardial cells. Meanwhile, spatial discrimination revealed that discordant and regional action potential property changes had a higher influence on T-wave alternans amplitude than concordant changes. Notably, varying T-wave alternans sources yielded distinct body surface potential map patterns for T-wave alternans amplitude, which can be used for location of regions within hearts exhibiting impaired repolarization. The highest ability for T-wave alternans detection was achieved in lead V1. Ultimately, we proposed new parameters Vector Magnitude Alternans and Vector Angle Alternans, with higher ability for T-wave alternans detection when using multi-lead electrocardiographic signals processing than for single leads. Finally, QT alternans was found to be associated with the process of T-wave alternans generation. Conclusions The distributions of the body surface T-wave alternans amplitude have been shown to have unique patterns depending on the type of alternans (concordant, discordant or regional) and the location of the disturbance in the heart. The influence of epicardial cells on T-wave alternans development is significantly higher than that of mid-myocardial cells, among which the sub-endocardial layer exerted the highest influence. QT interval alternans is identified as a phenomenon that correlate with T-wave alternans.
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Affiliation(s)
- D Janusek
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, 4 Ks Trojdena Str., 02-109, Warsaw, Poland.
| | - J Svehlikova
- Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia
| | - J Zelinka
- Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia
| | - W Weigl
- Department of Surgical Sciences/Anaesthesiology and Intensive Care, Uppsala University, Akademiska Hospital, Uppsala, Sweden
| | - R Zaczek
- Department of Cardiology, Central Clinical Hospital of Medical University of Warsaw, Warsaw, Poland
| | - G Opolski
- Department of Cardiology, Central Clinical Hospital of Medical University of Warsaw, Warsaw, Poland
| | - M Tysler
- Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia
| | - R Maniewski
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, 4 Ks Trojdena Str., 02-109, Warsaw, Poland
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11
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Boukens BJ, Meijborg VMF, Belterman CN, Opthof T, Janse MJ, Schuessler RB, Coronel R, Efimov IR. Local transmural action potential gradients are absent in the isolated, intact dog heart but present in the corresponding coronary-perfused wedge. Physiol Rep 2018; 5:e13251. [PMID: 28554962 PMCID: PMC5449556 DOI: 10.14814/phy2.13251] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 03/20/2017] [Accepted: 03/20/2017] [Indexed: 11/24/2022] Open
Abstract
The left ventricular (LV) coronary‐perfused canine wedge preparation is a model commonly used for studying cardiac repolarization. In wedge studies, transmembrane potentials typically are recorded; whereas, extracellular electrical recordings are commonly used in intact hearts. We compared electrically measured activation recovery interval (ARI) patterns in the intact heart with those recorded at the same location in the LV wedge preparation. We also compared electrically recorded and optically obtained ARIs in the LV wedge preparation. Five Langendorff‐perfused canine hearts were paced from the right atrium. Local activation and repolarization times were measured with eight transmural needle electrodes. Subsequently, left ventricular coronary‐perfused wedge preparations were prepared from these hearts while the electrodes remained in place. Three electrodes remained at identical positions as in the intact heart. Both electrograms and optical action potentials were recorded (pacing cycle length 400–4000 msec) and activation and repolarization patterns were analyzed. ARIs found in the subepicardium were shorter than in the subendocardium in the LV wedge preparation but not in the intact heart. The transmural ARI gradient recorded at the cut surface of the wedge was not different from that recorded internally. ARIs recorded internally and at the cut surface in the LV wedge preparation, both correlated with optically recorded action potentials. ARI and RT gradients in the LV wedge preparation differed from those in the intact canine heart, implying that those observations in human LV wedge preparations also should be extrapolated to the intact human heart with caution.
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Affiliation(s)
- Bastiaan J Boukens
- Department of Biomedical Engineering, George Washington University, Washington, District of Columbia.,Department of Medical Biology, University of Amsterdam, Amsterdam, The Netherlands
| | - Veronique M F Meijborg
- Department of Experimental and Clinical Cardiology, University of Amsterdam, Amsterdam, The Netherlands.,Netherlands Heart Institute, Holland Heart House, Utrecht, The Netherlands
| | - Charly N Belterman
- Department of Experimental and Clinical Cardiology, University of Amsterdam, Amsterdam, The Netherlands.,Institut LIRYC, Electrophysiology and Heart Modeling Institute, fondation Bordeaux Université, Pessac- Bordeaux, France
| | - Tobias Opthof
- Department of Experimental and Clinical Cardiology, University of Amsterdam, Amsterdam, The Netherlands.,Department of Medical Physiology, University of Utrecht, Utrecht, The Netherlands
| | - Michiel J Janse
- Department of Experimental and Clinical Cardiology, University of Amsterdam, Amsterdam, The Netherlands
| | | | - Ruben Coronel
- Department of Experimental and Clinical Cardiology, University of Amsterdam, Amsterdam, The Netherlands.,Institut LIRYC, Electrophysiology and Heart Modeling Institute, fondation Bordeaux Université, Pessac- Bordeaux, France
| | - Igor R Efimov
- Department of Biomedical Engineering, George Washington University, Washington, District of Columbia.,Institut LIRYC, Electrophysiology and Heart Modeling Institute, fondation Bordeaux Université, Pessac- Bordeaux, France
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