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Filatova TS, Kuzmin VS, Guskova VO, Abramochkin DV. Sodium current preserves electrical excitability in the heart of hibernating ground squirrel (Citellus undulatus). Comp Biochem Physiol A Mol Integr Physiol 2023; 282:111452. [PMID: 37207928 DOI: 10.1016/j.cbpa.2023.111452] [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: 04/10/2023] [Revised: 05/16/2023] [Accepted: 05/16/2023] [Indexed: 05/21/2023]
Abstract
Hibernating mammals are capable of maintaining normal cardiac function at low temperatures. Excitability of cardiac myocytes crucially depends on the fast sodium current (INa), which is decreased in hypothermia due to both depolarization of resting membrane potential and direct negative effect of low temperature. Therefore, INa in hibernating mammals should have specific features allowing to maintain excitability of myocardium at low temperatures. The current-voltage dependence of INa, its steady-state inactivation and activation and recovery from inactivation were studied in winter hibernating (WH) and summer active (SA) ground squirrels and in rats using whole-cell patch clamp at 10 °C and 20 °C. INa peak amplitude and the parameters of steady-state activation and inactivation curves did not differ between SA and WH ground squirrels at both temperatures. However, at both temperatures strong positive shift of activation and inactivation curves by 5-12 mV was observed in both WH and SA ground squirrels if compared to rats. This peculiarity of cardiac INa in ground squirrels helps to maintain excitability in conditions of depolarized resting membrane potential. The time course of INa recovery from inactivation at 10 °C was faster in WH than in SA ground squirrels, which could ensure normal activation of myocardium during hibernation.
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Affiliation(s)
- Tatiana S Filatova
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye Gory, 1, 12, Moscow 119234, Russia
| | - Vladislav S Kuzmin
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye Gory, 1, 12, Moscow 119234, Russia; Laboratory of Cardiac Electrophysiology, Chazov National Medical Research Center for Cardiology, Moscow, Russia
| | - Viktoria O Guskova
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye Gory, 1, 12, Moscow 119234, Russia
| | - Denis V Abramochkin
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye Gory, 1, 12, Moscow 119234, Russia.
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2
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OUP accepted manuscript. Eur Heart J 2022; 43:1248-1250. [DOI: 10.1093/eurheartj/ehab912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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3
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He YJ, Li QH, Zhou K, Jiang R, Jiang C, Pan JT, Zheng D, Zheng B, Zhang H. Topological charge-density method of identifying phase singularities in cardiac fibrillation. Phys Rev E 2021; 104:014213. [PMID: 34412332 DOI: 10.1103/physreve.104.014213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 06/28/2021] [Indexed: 11/07/2022]
Abstract
Spiral waves represent the key motifs of typical self-sustained dynamical patterns in excitable systems such as cardiac tissue. The motion of phase singularities (PSs) that lies at the center of spiral waves captures many qualitative and, in some cases, quantitative features of their complex dynamics. Recent clinical studies suggested that ablating the tissue at PS locations may cure atrial fibrillation. Here, we propose a different method to determine the location of PSs. Starting from the definition of the topological charge of spiral waves, we obtain the expression of the topological charge density in a discrete case. With this expression, we can calculate the topological charge at each grid in the space directly, so as to accurately identify the position of PSs.
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Affiliation(s)
- Yin-Jie He
- Zhejiang Institute of Modern Physics and Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Qi-Hao Li
- Zhejiang Institute of Modern Physics and Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Kuangshi Zhou
- Department of Cardiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, China
| | - Ruhong Jiang
- Department of Cardiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, China
| | - Chenyang Jiang
- Department of Cardiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, China
| | - Jun-Ting Pan
- Ocean College, Zhejiang University, Zhoushan 316021, China
| | - Dafang Zheng
- Zhejiang Institute of Modern Physics and Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Bo Zheng
- Zhejiang Institute of Modern Physics and Department of Physics, Zhejiang University, Hangzhou 310027, China.,School of Physics and Astronomy, Yunnan University, Kunming 650091, China
| | - Hong Zhang
- Zhejiang Institute of Modern Physics and Department of Physics, Zhejiang University, Hangzhou 310027, China
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4
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Dharmaprani D, Jenkins E, Aguilar M, Quah JX, Lahiri A, Tiver K, Mitchell L, Kuklik P, Meyer C, Willems S, Clayton R, Nash M, Nattel S, McGavigan AD, Ganesan AN. M/M/Infinity Birth-Death Processes - A Quantitative Representational Framework to Summarize and Explain Phase Singularity and Wavelet Dynamics in Atrial Fibrillation. Front Physiol 2021; 11:616866. [PMID: 33519522 PMCID: PMC7841497 DOI: 10.3389/fphys.2020.616866] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 12/16/2020] [Indexed: 01/25/2023] Open
Abstract
Rationale A quantitative framework to summarize and explain the quasi-stationary population dynamics of unstable phase singularities (PS) and wavelets in human atrial fibrillation (AF) is at present lacking. Building on recent evidence showing that the formation and destruction of PS and wavelets in AF can be represented as renewal processes, we sought to establish such a quantitative framework, which could also potentially provide insight into the mechanisms of spontaneous AF termination. Objectives Here, we hypothesized that the observed number of PS or wavelets in AF could be governed by a common set of renewal rate constants λ f (for PS or wavelet formation) and λ d (PS or wavelet destruction), with steady-state population dynamics modeled as an M/M/∞ birth-death process. We further hypothesized that changes to the M/M/∞ birth-death matrix would explain spontaneous AF termination. Methods and Results AF was studied in in a multimodality, multispecies study in humans, animal experimental models (rats and sheep) and Ramirez-Nattel-Courtemanche model computer simulations. We demonstrated: (i) that λ f and λ d can be combined in a Markov M/M/∞ process to accurately model the observed average number and population distribution of PS and wavelets in all systems at different scales of mapping; and (ii) that slowing of the rate constants λ f and λ d is associated with slower mixing rates of the M/M/∞ birth-death matrix, providing an explanation for spontaneous AF termination. Conclusion M/M/∞ birth-death processes provide an accurate quantitative representational architecture to characterize PS and wavelet population dynamics in AF, by providing governing equations to understand the regeneration of PS and wavelets during sustained AF, as well as providing insight into the mechanism of spontaneous AF termination.
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Affiliation(s)
- Dhani Dharmaprani
- College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia.,College of Science and Engineering, Flinders University, Adelaide, SA, Australia
| | - Evan Jenkins
- College of Science and Engineering, Flinders University, Adelaide, SA, Australia
| | - Martin Aguilar
- The Research Center, Montréal Heart Institute and Université de Montréal, Montréal, QC, Canada
| | - Jing X Quah
- College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia.,Department of Cardiovascular Medicine, Flinders Medical Centre, Bedford Park, SA, Australia
| | - Anandaroop Lahiri
- Department of Cardiovascular Medicine, Flinders Medical Centre, Bedford Park, SA, Australia
| | - Kathryn Tiver
- Department of Cardiovascular Medicine, Flinders Medical Centre, Bedford Park, SA, Australia
| | - Lewis Mitchell
- School of Mathematical Sciences, University of Adelaide, Adelaide, SA, Australia
| | | | | | | | - Richard Clayton
- Insigneo Institute for in silico Medicine, University of Sheffield, Sheffield, United Kingdom
| | - Martyn Nash
- Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Stanley Nattel
- The Research Center, Montréal Heart Institute and Université de Montréal, Montréal, QC, Canada
| | - Andrew D McGavigan
- College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia.,Department of Cardiovascular Medicine, Flinders Medical Centre, Bedford Park, SA, Australia
| | - Anand N Ganesan
- College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia.,Department of Cardiovascular Medicine, Flinders Medical Centre, Bedford Park, SA, Australia
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5
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Meo M, Denis A, Sacher F, Duchâteau J, Cheniti G, Puyo S, Bear L, Jaïs P, Hocini M, Haïssaguerre M, Bernus O, Dubois R. Insights Into the Spatiotemporal Patterns of Complexity of Ventricular Fibrillation by Multilead Analysis of Body Surface Potential Maps. Front Physiol 2020; 11:554838. [PMID: 33071814 PMCID: PMC7538856 DOI: 10.3389/fphys.2020.554838] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 08/12/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Ventricular fibrillation (VF) is the main cause of sudden cardiac death, but its mechanisms are still unclear. We propose a noninvasive approach to describe the progression of VF complexity from body surface potential maps (BSPMs). METHODS We mapped 252 VF episodes (16 ± 10 s) with a 252-electrode vest in 110 patients (89 male, 47 ± 18 years): 50 terminated spontaneously, otherwise by electrical cardioversion (DCC). Changes in complexity were assessed between the onset ("VF start") and the end ("VF end") of VF by the nondipolar component index (N D I B S P M ), measuring the fraction of energy nonpreserved by an equivalent 3D dipole from BSPMs. Higher NDI reflected lower VF organization. We also examined other standard body surface markers of VF dynamics, including fibrillatory wave amplitude (A BSPM ), surface cycle length (BsCL BSPM ) and Shannon entropy (S h E n B S P M ). Differences between patients with and without structural heart diseases (SHD, 32 vs. NSHD, 78) were also tested at those stages. Electrocardiographic features were validated with simultaneous endocardium cycle length (CL) in a subset of 30 patients. RESULTS All BSPM markers measure an increase in electrical complexity during VF (p < 0.0001), and more significantly in NSHD patients. Complexity is significantly higher at the end of sustained VF episodes requiring DCC. Intraepisode intracardiac CL shortening (VF start 197 ± 24 vs. VF end 169 ± 20 ms; p < 0.0001) correlates with an increase in NDI, and decline in surface CL, f-wave amplitude, and entropy (p < 0.0001). In SHD patients VF is initially more complex than in NSHD patients (N D I B S P M , p = 0.0007; S h E n B S P M , p < 0.0001), with moderately slower (BsCL BSPM , p = 0.06), low-amplitude f-waves (A BSPM , p < 0.0001). In this population, lower NDI (p = 0.004) and slower surface CL (p = 0.008) at early stage of VF predict self-termination. In the NSHD group, a more abrupt increase in VF complexity is quantified by all BSPM parameters during sustained VF (p < 0.0001), whereas arrhythmia evolution is stable during self-terminating episodes, hinting at additional mechanisms driving VF dynamics. CONCLUSION Multilead BSPM analysis underlines distinct degrees of VF complexity based on substrate characteristics.
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Affiliation(s)
- Marianna Meo
- Institute of Electrophysiology and Heart Modeling (IHU Liryc), Foundation Bordeaux University, Bordeaux, France
- Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, University of Bordeaux, Bordeaux, France
- Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Institut National de la Santé et de la Recherche Médicale, Bordeaux, France
| | - Arnaud Denis
- Institute of Electrophysiology and Heart Modeling (IHU Liryc), Foundation Bordeaux University, Bordeaux, France
- Electrophysiology and Ablation Unit, Bordeaux University Hospital, Bordeaux, France
| | - Frédéric Sacher
- Institute of Electrophysiology and Heart Modeling (IHU Liryc), Foundation Bordeaux University, Bordeaux, France
- Electrophysiology and Ablation Unit, Bordeaux University Hospital, Bordeaux, France
| | - Josselin Duchâteau
- Institute of Electrophysiology and Heart Modeling (IHU Liryc), Foundation Bordeaux University, Bordeaux, France
- Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, University of Bordeaux, Bordeaux, France
- Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Institut National de la Santé et de la Recherche Médicale, Bordeaux, France
- Electrophysiology and Ablation Unit, Bordeaux University Hospital, Bordeaux, France
| | - Ghassen Cheniti
- Institute of Electrophysiology and Heart Modeling (IHU Liryc), Foundation Bordeaux University, Bordeaux, France
- Electrophysiology and Ablation Unit, Bordeaux University Hospital, Bordeaux, France
| | - Stéphane Puyo
- Institute of Electrophysiology and Heart Modeling (IHU Liryc), Foundation Bordeaux University, Bordeaux, France
- Electrophysiology and Ablation Unit, Bordeaux University Hospital, Bordeaux, France
| | - Laura Bear
- Institute of Electrophysiology and Heart Modeling (IHU Liryc), Foundation Bordeaux University, Bordeaux, France
- Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, University of Bordeaux, Bordeaux, France
- Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Institut National de la Santé et de la Recherche Médicale, Bordeaux, France
| | - Pierre Jaïs
- Institute of Electrophysiology and Heart Modeling (IHU Liryc), Foundation Bordeaux University, Bordeaux, France
- Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, University of Bordeaux, Bordeaux, France
- Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Institut National de la Santé et de la Recherche Médicale, Bordeaux, France
- Electrophysiology and Ablation Unit, Bordeaux University Hospital, Bordeaux, France
| | - Mélèze Hocini
- Institute of Electrophysiology and Heart Modeling (IHU Liryc), Foundation Bordeaux University, Bordeaux, France
- Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, University of Bordeaux, Bordeaux, France
- Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Institut National de la Santé et de la Recherche Médicale, Bordeaux, France
- Electrophysiology and Ablation Unit, Bordeaux University Hospital, Bordeaux, France
| | - Michel Haïssaguerre
- Institute of Electrophysiology and Heart Modeling (IHU Liryc), Foundation Bordeaux University, Bordeaux, France
- Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, University of Bordeaux, Bordeaux, France
- Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Institut National de la Santé et de la Recherche Médicale, Bordeaux, France
- Electrophysiology and Ablation Unit, Bordeaux University Hospital, Bordeaux, France
| | - Olivier Bernus
- Institute of Electrophysiology and Heart Modeling (IHU Liryc), Foundation Bordeaux University, Bordeaux, France
- Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, University of Bordeaux, Bordeaux, France
- Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Institut National de la Santé et de la Recherche Médicale, Bordeaux, France
| | - Rémi Dubois
- Institute of Electrophysiology and Heart Modeling (IHU Liryc), Foundation Bordeaux University, Bordeaux, France
- Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, University of Bordeaux, Bordeaux, France
- Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Institut National de la Santé et de la Recherche Médicale, Bordeaux, France
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Child N, Clayton RH, Roney CH, Laughner JI, Shuros A, Neuzil P, Petru J, Jackson T, Porter B, Bostock J, Niederer SA, Razavi RS, Rinaldi CA, Taggart P, Wright MJ, Gill J. Unraveling the Underlying Arrhythmia Mechanism in Persistent Atrial Fibrillation: Results From the STARLIGHT Study. Circ Arrhythm Electrophysiol 2019; 11:e005897. [PMID: 29858382 DOI: 10.1161/circep.117.005897] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 03/20/2018] [Indexed: 11/16/2022]
Abstract
BACKGROUND The mechanisms that initiate and sustain persistent atrial fibrillation are not well characterized. Ablation results remain significantly worse than in paroxysmal atrial fibrillation in which the mechanism is better understood and subsequent targeted therapy has been developed. The aim of this study was to characterize and quantify patterns of activation during atrial fibrillation using contact mapping. METHODS Patients with persistent atrial fibrillation (n=14; mean age, 61±8 years; ejection fraction, 59±10%) underwent simultaneous biatrial contact mapping with 64 electrode catheters. The atrial electrograms were transformed into phase, and subsequent spatiotemporal mapping was performed to identify phase singularities (PSs). RESULTS PSs were located in both atria, but we observed more PSs in the left atrium compared with the right atrium (779±302, 552±235; P=0.015). Although some PSs of duration sufficient to complete >1 rotation were detected, the maximum PS duration was only 1150 ms, and the vast majority (97%) of PSs persisted for too short a period to complete a full rotation. Although in selected patients there was evidence of PS local clustering, overall, PSs were distributed globally throughout both chambers with no clear anatomic predisposition. In a subset of patients (n=7), analysis was repeated using an alternative established atrial PS mapping technique, which confirmed our initial findings. CONCLUSIONS No sustained rotors or localized drivers were detected, and instead, the mechanism of arrhythmia maintenance was consistent with the multiple wavelet hypothesis, with passive activation of short-lived rotational activity. CLINICAL TRIAL REGISTRATION URL: https://www.clinicaltrials.gov. Unique identifier: NCT01765075.
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Affiliation(s)
- Nicholas Child
- Department of Imaging Sciences and Biomedical Engineering, King's College London, United Kingdom (N.C., C.R.R., T.J., B.P., S.A.N., R.S.R.).
| | - Richard H Clayton
- INSIGNEO Institute for In Silico Medicine, University of Sheffield, United Kingdom (R.H.C.)
| | - Caroline H Roney
- Department of Imaging Sciences and Biomedical Engineering, King's College London, United Kingdom (N.C., C.R.R., T.J., B.P., S.A.N., R.S.R.)
| | | | - Allan Shuros
- Boston Scientific Corp, St. Paul, MN (J.I.L., A.S.)
| | - Petr Neuzil
- Department of Cardiology, Na Holmolce Hospital, Prague, Czech Republic (P.N., J.P.)
| | - Jan Petru
- Department of Cardiology, Na Holmolce Hospital, Prague, Czech Republic (P.N., J.P.)
| | - Tom Jackson
- Department of Imaging Sciences and Biomedical Engineering, King's College London, United Kingdom (N.C., C.R.R., T.J., B.P., S.A.N., R.S.R.)
| | - Bradley Porter
- Department of Imaging Sciences and Biomedical Engineering, King's College London, United Kingdom (N.C., C.R.R., T.J., B.P., S.A.N., R.S.R.)
| | - Julian Bostock
- Department of Cardiology, Guy's and St Thomas' Hospital, London, United Kingdom (J.B., C.A.R., M.J.W., J.G.)
| | - Steven A Niederer
- Department of Imaging Sciences and Biomedical Engineering, King's College London, United Kingdom (N.C., C.R.R., T.J., B.P., S.A.N., R.S.R.)
| | - Reza S Razavi
- Department of Imaging Sciences and Biomedical Engineering, King's College London, United Kingdom (N.C., C.R.R., T.J., B.P., S.A.N., R.S.R.)
| | - Christopher A Rinaldi
- Department of Cardiology, Guy's and St Thomas' Hospital, London, United Kingdom (J.B., C.A.R., M.J.W., J.G.)
| | | | - Matthew J Wright
- Department of Cardiology, Guy's and St Thomas' Hospital, London, United Kingdom (J.B., C.A.R., M.J.W., J.G.)
| | - Jaswinder Gill
- Department of Cardiology, Guy's and St Thomas' Hospital, London, United Kingdom (J.B., C.A.R., M.J.W., J.G.)
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7
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Vandersickel N, Watanabe M, Tao Q, Fostier J, Zeppenfeld K, Panfilov AV. Dynamical anchoring of distant arrhythmia sources by fibrotic regions via restructuring of the activation pattern. PLoS Comput Biol 2018; 14:e1006637. [PMID: 30571689 PMCID: PMC6319787 DOI: 10.1371/journal.pcbi.1006637] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 01/04/2019] [Accepted: 11/09/2018] [Indexed: 11/27/2022] Open
Abstract
Rotors are functional reentry sources identified in clinically relevant cardiac arrhythmias, such as ventricular and atrial fibrillation. Ablation targeting rotor sites has resulted in arrhythmia termination. Recent clinical, experimental and modelling studies demonstrate that rotors are often anchored around fibrotic scars or regions with increased fibrosis. However, the mechanisms leading to abundance of rotors at these locations are not clear. The current study explores the hypothesis whether fibrotic scars just serve as anchoring sites for the rotors or whether there are other active processes which drive the rotors to these fibrotic regions. Rotors were induced at different distances from fibrotic scars of various sizes and degree of fibrosis. Simulations were performed in a 2D model of human ventricular tissue and in a patient-specific model of the left ventricle of a patient with remote myocardial infarction. In both the 2D and the patient-specific model we found that without fibrotic scars, the rotors were stable at the site of their initiation. However, in the presence of a scar, rotors were eventually dynamically anchored from large distances by the fibrotic scar via a process of dynamical reorganization of the excitation pattern. This process coalesces with a change from polymorphic to monomorphic ventricular tachycardia. Rotors are waves of cardiac excitation like a tornado causing cardiac arrhythmia. Recent research shows that they are found in ventricular and atrial fibrillation. Burning (via ablation) the site of a rotor can result in the termination of the arrhythmia. Recent studies showed that rotors are often anchored to regions surrounding scar tissue, where part of the tissue still survived called fibrotic tissue. However, it is unclear why these rotors anchor to these locations. Therefore, in this work, we investigated why rotors are so abundant in fibrotic tissue with the help of computer simulations. We performed simulations in a 2D model of human ventricular tissue and in a patient-specific model of a patient with an infarction. We found that even when rotors are initially at large distances from the fibrotic region, they are attracted by this region, to finally end up at the fibrotic tissue. We called this process dynamical anchoring and explained how the process works.
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Affiliation(s)
- Nele Vandersickel
- Department of Physics and Astronomy, Ghent University, Belgium
- * E-mail: (NV); (AVP)
| | - Masaya Watanabe
- Department of Cardiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Qian Tao
- Department of Radiology, Division of Image Processing, Leiden University Medical Centre, Leiden, the Netherlands
| | - Jan Fostier
- Department of Information Technology (INTEC), IDLab, Ghent University — imec, Ghent, Belgium
| | - Katja Zeppenfeld
- Department of Cardiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Alexander V. Panfilov
- Department of Physics and Astronomy, Ghent University, Belgium
- Department of Cardiology, Leiden University Medical Center, Leiden, the Netherlands
- Laboratory of Computational Biology and Medicine, Ural Federal University, Ekaterinburg, Russia
- * E-mail: (NV); (AVP)
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8
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Handa BS, Roney CH, Houston C, Qureshi NA, Li X, Pitcher DS, Chowdhury RA, Lim PB, Dupont E, Niederer SA, Cantwell CD, Peters NS, Ng FS. Analytical approaches for myocardial fibrillation signals. Comput Biol Med 2018; 102:315-326. [PMID: 30025847 PMCID: PMC6215772 DOI: 10.1016/j.compbiomed.2018.07.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 07/11/2018] [Accepted: 07/11/2018] [Indexed: 12/11/2022]
Abstract
Atrial and ventricular fibrillation are complex arrhythmias, and their underlying mechanisms remain widely debated and incompletely understood. This is partly because the electrical signals recorded during myocardial fibrillation are themselves complex and difficult to interpret with simple analytical tools. There are currently a number of analytical approaches to handle fibrillation data. Some of these techniques focus on mapping putative drivers of myocardial fibrillation, such as dominant frequency, organizational index, Shannon entropy and phase mapping. Other techniques focus on mapping the underlying myocardial substrate sustaining fibrillation, such as voltage mapping and complex fractionated electrogram mapping. In this review, we discuss these techniques, their application and their limitations, with reference to our experimental and clinical data. We also describe novel tools including a new algorithm to map microreentrant circuits sustaining fibrillation.
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Affiliation(s)
- Balvinder S Handa
- ElectroCardioMaths, Imperial Centre for Cardiac Engineering, National Heart & Lung Institute, Imperial College London, United Kingdom
| | - Caroline H Roney
- Division of Imaging Sciences and Bioengineering, King's College London, United Kingdom
| | - Charles Houston
- ElectroCardioMaths, Imperial Centre for Cardiac Engineering, National Heart & Lung Institute, Imperial College London, United Kingdom
| | - Norman A Qureshi
- ElectroCardioMaths, Imperial Centre for Cardiac Engineering, National Heart & Lung Institute, Imperial College London, United Kingdom
| | - Xinyang Li
- ElectroCardioMaths, Imperial Centre for Cardiac Engineering, National Heart & Lung Institute, Imperial College London, United Kingdom
| | - David S Pitcher
- ElectroCardioMaths, Imperial Centre for Cardiac Engineering, National Heart & Lung Institute, Imperial College London, United Kingdom
| | - Rasheda A Chowdhury
- ElectroCardioMaths, Imperial Centre for Cardiac Engineering, National Heart & Lung Institute, Imperial College London, United Kingdom
| | - Phang Boon Lim
- ElectroCardioMaths, Imperial Centre for Cardiac Engineering, National Heart & Lung Institute, Imperial College London, United Kingdom
| | - Emmanuel Dupont
- ElectroCardioMaths, Imperial Centre for Cardiac Engineering, National Heart & Lung Institute, Imperial College London, United Kingdom
| | - Steven A Niederer
- Division of Imaging Sciences and Bioengineering, King's College London, United Kingdom
| | - Chris D Cantwell
- ElectroCardioMaths, Imperial Centre for Cardiac Engineering, National Heart & Lung Institute, Imperial College London, United Kingdom; Department of Aeronautics, Imperial College London, United Kingdom
| | - Nicholas S Peters
- ElectroCardioMaths, Imperial Centre for Cardiac Engineering, National Heart & Lung Institute, Imperial College London, United Kingdom
| | - Fu Siong Ng
- ElectroCardioMaths, Imperial Centre for Cardiac Engineering, National Heart & Lung Institute, Imperial College London, United Kingdom.
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9
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Spatio-temporal Organization During Ventricular Fibrillation in the Human Heart. Ann Biomed Eng 2018; 46:864-876. [PMID: 29546467 PMCID: PMC5934463 DOI: 10.1007/s10439-018-2007-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 03/07/2018] [Indexed: 11/11/2022]
Abstract
In this paper, we present a novel approach to quantify the spatio-temporal organization of electrical activation during human ventricular fibrillation (VF). We propose three different methods based on correlation analysis, graph theoretical measures and hierarchical clustering. Using the proposed approach, we quantified the level of spatio-temporal organization during three episodes of VF in ten patients, recorded using multi-electrode epicardial recordings with 30 s coronary perfusion, 150 s global myocardial ischaemia and 30 s reflow. Our findings show a steady decline in spatio-temporal organization from the onset of VF with coronary perfusion. We observed transient increases in spatio-temporal organization during global myocardial ischaemia. However, the decline in spatio-temporal organization continued during reflow. Our results were consistent across all patients, and were consistent with the numbers of phase singularities. Our findings show that the complex spatio-temporal patterns can be studied using complex network analysis.
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10
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Abstract
Objectives The objective of this study was to evaluate the spatio-temporal organization and progression of human ventricular fibrillation (VF) in the left (LV) and right (RV) ventricles. Background Studies suggest that localized sources contribute to VF maintenance, but the evolution of VF episodes has not been quantified. Methods Synchrony between electrograms recorded from 25 patients with induced VF is computed and used to define the Asynchronous Index (ASI), indicating regions which are out-of-step with surrounding tissue. Computer simulations show that ASI can identify the location of VF-maintaining sources, where larger values of ASImax correlate with more stable sources. Results Automated synchrony analysis shows elevated values of ASI in a majority of self-terminating episodes (LV: 8/9, RV: 7/8) and sustained episodes (LV: 11/11, RV: 12/12). The locations of ASImax in sustained episodes co-localize with rotor cores when rotational activity is simultaneously present in phase maps (LV: 8/8, RV: 5/7, p<.05). The distribution of ASImax differentiates self-terminating from sustained episodes (mean ASImax = 0.60±0.14 and 0.70±0.16, respectively; p=0.01). Across sustained episodes the LV exhibits an increase in ASImax with time. Conclusions Quantitative analysis identifies localized asynchronous regions that correlate with sources in VF, with sustained episodes evolving to exhibit more stable activation in the LV. This successive increase in stability indicates a stabilizing agent may be responsible for perpetuating fibrillation in a "migrate-and-capture" mechanism in the LV.
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11
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Lekli I, Haines DD, Balla G, Tosaki A. Autophagy: an adaptive physiological countermeasure to cellular senescence and ischaemia/reperfusion-associated cardiac arrhythmias. J Cell Mol Med 2016; 21:1058-1072. [PMID: 27997746 PMCID: PMC5431132 DOI: 10.1111/jcmm.13053] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 11/04/2016] [Indexed: 12/15/2022] Open
Abstract
Oxidative stress placed on tissues that involved in pathogenesis of a disease activates compensatory metabolic changes, such as DNA damage repair that in turn causes intracellular accumulation of detritus and ‘proteotoxic stress’, leading to emergence of ‘senescent’ cellular phenotypes, which express high levels of inflammatory mediators, resulting in degradation of tissue function. Proteotoxic stress resulting from hyperactive inflammation following reperfusion of ischaemic tissue causes accumulation of proteinaceous debris in cells of the heart in ways that cause potentially fatal arrhythmias, in particular ventricular fibrillation (VF). An adaptive response to VF is occurrence of autophagy, an intracellular bulk degradation of damaged macromolecules and organelles that may restore cellular and tissue homoeostasis, improving chances for recovery. Nevertheless, depending on the type and intensity of stressors and inflammatory responses, autophagy may become pathological, resulting in excessive cell death. The present review examines the multilayered defences that cells have evolved to reduce proteotoxic stress by degradation of potentially toxic material beginning with endoplasmic reticulum‐associated degradation, and the unfolded protein response, which are mechanisms for removal from the endoplasmic reticulum of misfolded proteins, and then progressing through the stages of autophagy, including descriptions of autophagosomes and related vesicular structures which process material for degradation and autophagy‐associated proteins including Beclin‐1 and regulatory complexes. The physiological roles of each mode of proteotoxic defence will be examined along with consideration of how emerging understanding of autophagy, along with a newly discovered regulatory cell type called telocytes, may be used to augment existing strategies for the prevention and management of cardiovascular disease.
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Affiliation(s)
- Istvan Lekli
- Department of Pharmacology, Faculty of Pharmacy, University of Debrecen, Debrecen, Hungary
| | - David Donald Haines
- Department of Pharmacology, Faculty of Pharmacy, University of Debrecen, Debrecen, Hungary
| | - Gyorgy Balla
- Department of Pediatrics, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary.,Hemostasis, Thrombosis and Vascular Biology Research Group, Hungarian Academy of Sciences, Debrecen, Hungary
| | - Arpad Tosaki
- Department of Pharmacology, Faculty of Pharmacy, University of Debrecen, Debrecen, Hungary
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12
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Rodriguez B, Carusi A, Abi-Gerges N, Ariga R, Britton O, Bub G, Bueno-Orovio A, Burton RAB, Carapella V, Cardone-Noott L, Daniels MJ, Davies MR, Dutta S, Ghetti A, Grau V, Harmer S, Kopljar I, Lambiase P, Lu HR, Lyon A, Minchole A, Muszkiewicz A, Oster J, Paci M, Passini E, Severi S, Taggart P, Tinker A, Valentin JP, Varro A, Wallman M, Zhou X. Human-based approaches to pharmacology and cardiology: an interdisciplinary and intersectorial workshop. Europace 2016; 18:1287-98. [PMID: 26622055 PMCID: PMC5006958 DOI: 10.1093/europace/euv320] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 08/20/2015] [Indexed: 12/12/2022] Open
Abstract
Both biomedical research and clinical practice rely on complex datasets for the physiological and genetic characterization of human hearts in health and disease. Given the complexity and variety of approaches and recordings, there is now growing recognition of the need to embed computational methods in cardiovascular medicine and science for analysis, integration and prediction. This paper describes a Workshop on Computational Cardiovascular Science that created an international, interdisciplinary and inter-sectorial forum to define the next steps for a human-based approach to disease supported by computational methodologies. The main ideas highlighted were (i) a shift towards human-based methodologies, spurred by advances in new in silico, in vivo, in vitro, and ex vivo techniques and the increasing acknowledgement of the limitations of animal models. (ii) Computational approaches complement, expand, bridge, and integrate in vitro, in vivo, and ex vivo experimental and clinical data and methods, and as such they are an integral part of human-based methodologies in pharmacology and medicine. (iii) The effective implementation of multi- and interdisciplinary approaches, teams, and training combining and integrating computational methods with experimental and clinical approaches across academia, industry, and healthcare settings is a priority. (iv) The human-based cross-disciplinary approach requires experts in specific methodologies and domains, who also have the capacity to communicate and collaborate across disciplines and cross-sector environments. (v) This new translational domain for human-based cardiology and pharmacology requires new partnerships supported financially and institutionally across sectors. Institutional, organizational, and social barriers must be identified, understood and overcome in each specific setting.
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Affiliation(s)
- Blanca Rodriguez
- Department of Computer Science, University of Oxford, Oxford, UK
| | | | - Najah Abi-Gerges
- AnaBios Corporation, San Diego Science Center, San Diego, CA 92109, USA
| | - Rina Ariga
- Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Oliver Britton
- Department of Computer Science, University of Oxford, Oxford, UK
| | - Gil Bub
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | | | - Rebecca A B Burton
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | | | | | - Matthew J Daniels
- Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | | | - Sara Dutta
- Department of Computer Science, University of Oxford, Oxford, UK
| | - Andre Ghetti
- AnaBios Corporation, San Diego Science Center, San Diego, CA 92109, USA
| | - Vicente Grau
- Department of Engineering Science, University of Oxford, Oxford, UK
| | - Stephen Harmer
- William Harvey Heart Centre, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London, UK
| | - Ivan Kopljar
- Discovery Sciences, Dis&Dev Research, Janssen Pharmaceutical NV, Beerse, Belgium
| | - Pier Lambiase
- Institute of Cardiovascular Science, University College London, Bars Heart Centre, London, UK
| | - Hua Rong Lu
- Discovery Sciences, Dis&Dev Research, Janssen Pharmaceutical NV, Beerse, Belgium
| | - Aurore Lyon
- Department of Computer Science, University of Oxford, Oxford, UK
| | - Ana Minchole
- Department of Computer Science, University of Oxford, Oxford, UK
| | - Anna Muszkiewicz
- Department of Computer Science, University of Oxford, Oxford, UK
| | - Julien Oster
- Department of Engineering Science, University of Oxford, Oxford, UK
| | - Michelangelo Paci
- Department of Electronics and Communications Engineering, Tampere University of Technology, BioMediTech, Tampere, Finland
| | - Elisa Passini
- Department of Computer Science, University of Oxford, Oxford, UK
| | - Stefano Severi
- Department of Electrical, Electronic and Information Engineering, University of Bologna, Cesena 47521, Italy
| | - Peter Taggart
- Institute of Cardiovascular Science, University College London, Bars Heart Centre, London, UK
| | - Andy Tinker
- William Harvey Heart Centre, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London, UK
| | | | | | | | - Xin Zhou
- Department of Computer Science, University of Oxford, Oxford, UK
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13
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Krummen DE, Ho G, Villongco CT, Hayase J, Schricker AA. Ventricular fibrillation: triggers, mechanisms and therapies. Future Cardiol 2016; 12:373-90. [PMID: 27120223 DOI: 10.2217/fca-2016-0001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Ventricular fibrillation (VF) is a common, life-threatening arrhythmia responsible for significant morbidity and mortality. Due to challenges in safely mapping VF, a comprehensive understanding of its mechanisms remains elusive. Recent findings have provided new insights into mechanisms that sustain early VF. Notably, the central role of electrical rotors and catheter-based ablation of VF rotor substrate have been recently reported. In this article, we will review data regarding four stages of VF: initiation, transition, maintenance and evolution. We will discuss the particular mechanisms for each stage and therapies targeting these mechanisms. We also examine inherited arrhythmia syndromes, including the mechanisms and therapies specific to each. We hope that the overview of VF outlined in this work will assist other investigators in designing future therapies to interrupt this life-threatening arrhythmia.
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Affiliation(s)
- David E Krummen
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.,Department of Medicine, VA San Diego Healthcare System, 3350 La Jolla Village Drive, San Diego, CA 92161, USA
| | - Gordon Ho
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.,Department of Medicine, VA San Diego Healthcare System, 3350 La Jolla Village Drive, San Diego, CA 92161, USA
| | - Christopher T Villongco
- Department of Bioengineering, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Justin Hayase
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.,Department of Medicine, VA San Diego Healthcare System, 3350 La Jolla Village Drive, San Diego, CA 92161, USA
| | - Amir A Schricker
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.,Department of Medicine, VA San Diego Healthcare System, 3350 La Jolla Village Drive, San Diego, CA 92161, USA
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14
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Eisenmann ED, Rorabaugh BR, Zoladz PR. Acute Stress Decreases but Chronic Stress Increases Myocardial Sensitivity to Ischemic Injury in Rodents. Front Psychiatry 2016; 7:71. [PMID: 27199778 PMCID: PMC4843048 DOI: 10.3389/fpsyt.2016.00071] [Citation(s) in RCA: 10] [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: 01/25/2016] [Accepted: 04/08/2016] [Indexed: 12/18/2022] Open
Abstract
Cardiovascular disease (CVD) is the largest cause of mortality worldwide, and stress is a significant contributor to the development of CVD. The relationship between acute and chronic stress and CVD is well evidenced. Acute stress can lead to arrhythmias and ischemic injury. However, recent evidence in rodent models suggests that acute stress can decrease sensitivity to myocardial ischemia-reperfusion injury (IRI). Conversely, chronic stress is arrhythmogenic and increases sensitivity to myocardial IRI. Few studies have examined the impact of validated animal models of stress-related psychological disorders on the ischemic heart. This review examines the work that has been completed using rat models to study the effects of stress on myocardial sensitivity to ischemic injury. Utilization of animal models of stress-related psychological disorders is critical in the prevention and treatment of cardiovascular disorders in patients experiencing stress-related psychiatric conditions.
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Affiliation(s)
- Eric D Eisenmann
- Department of Psychology, Sociology and Criminal Justice, Ohio Northern University , Ada, OH , USA
| | - Boyd R Rorabaugh
- Department of Pharmaceutical and Biomedical Sciences, Ohio Northern University , Ada, OH , USA
| | - Phillip R Zoladz
- Department of Psychology, Sociology and Criminal Justice, Ohio Northern University , Ada, OH , USA
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15
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Clayton RH. Models of ventricular arrhythmia mechanisms. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2015; 2013:1526-9. [PMID: 24109990 DOI: 10.1109/embc.2013.6609803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The mechanisms that initiate and sustain ventricular arrhythmias in the human heart are clinically important, but hard to study experimentally. In this study, a monodomain model of electrical activation was used to examine how dynamics of electrophysiology at the cell scale influence the surface activation patterns of VF at the tissue scale. Cellular electrophysiology was described with two variants of a phenomenological model of the human ventricular epicardial action potential. The tissue geometry was an 8.0 × 8.0 × 1.2 cm 3D tissue slab with axially symmetric anisotropy. In both cases an initial re-entrant wave fragmented into multiple wavelets of activation. The model variant with steep action potential duration restitution produced much more complex activation, with a greater average number of filaments (13.79) than the variant with less steep restitution (3.08). More complex activation was associated with proportionally fewer transmural filaments, and so the average number of epicardial wavefronts and phase singularities per filament was lower. The average number of epicardial phase singularities and wavefronts for the model variant with less steep restitution were consistent with experimental observations in the human heart. This study shows that small changes in cell scale dynamics can have a large influence on the complexity of re-entrant activation in simulated 3D tissue, as well as on the features observed on the epicardial surface.
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16
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Calvo D, Atienza F, Saiz J, Martínez L, Ávila P, Rubín J, Herreros B, Arenal Á, García-Fernández J, Ferrer A, Sebastián R, Martínez-Camblor P, Jalife J, Berenfeld O. Ventricular Tachycardia and Early Fibrillation in Patients With Brugada Syndrome and Ischemic Cardiomyopathy Show Predictable Frequency-Phase Properties on the Precordial ECG Consistent With the Respective Arrhythmogenic Substrate. Circ Arrhythm Electrophysiol 2015; 8:1133-43. [PMID: 26253505 PMCID: PMC4608487 DOI: 10.1161/circep.114.002717] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 07/23/2015] [Indexed: 11/16/2022]
Abstract
Supplemental Digital Content is available in the text. Ventricular fibrillation (VF) has been proposed to be maintained by localized high-frequency sources. We tested whether spectral-phase analysis of the precordial ECG enabled identification of periodic activation patterns generated by such sources.
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Affiliation(s)
- David Calvo
- From the Arrhythmia Unit, Hospital Universitario Central de Asturias, Oviedo, Spain (D.C., J.R.); Center for Arrhythmia Research, University of Michigan, Ann Arbor (J.J., O.B.); Arrhythmia Unit, Hospital General Universitario Gregorio Marañón, Madrid, Spain (F.A., P.Á., Á.A.); Centro de Investigación e Innovación en Bioingeniería, Ci2B, Universitat Politècnica de Valencia, Valencia, Spain (J.S., L.M., A.F.); Arrhythmia Unit, Hospital Río Hortega de Valladolid and Universitario de Burgos, Valladolid-Burgos, Spain (B.H., J.G.-F.); Universitat de Valencia, Valencia, Spain (R.S.); and Department of Statistics, Hospital Universitario Central de Asturias, Oviedo, Spain (P.M.-C.)
| | - Felipe Atienza
- From the Arrhythmia Unit, Hospital Universitario Central de Asturias, Oviedo, Spain (D.C., J.R.); Center for Arrhythmia Research, University of Michigan, Ann Arbor (J.J., O.B.); Arrhythmia Unit, Hospital General Universitario Gregorio Marañón, Madrid, Spain (F.A., P.Á., Á.A.); Centro de Investigación e Innovación en Bioingeniería, Ci2B, Universitat Politècnica de Valencia, Valencia, Spain (J.S., L.M., A.F.); Arrhythmia Unit, Hospital Río Hortega de Valladolid and Universitario de Burgos, Valladolid-Burgos, Spain (B.H., J.G.-F.); Universitat de Valencia, Valencia, Spain (R.S.); and Department of Statistics, Hospital Universitario Central de Asturias, Oviedo, Spain (P.M.-C.)
| | - Javier Saiz
- From the Arrhythmia Unit, Hospital Universitario Central de Asturias, Oviedo, Spain (D.C., J.R.); Center for Arrhythmia Research, University of Michigan, Ann Arbor (J.J., O.B.); Arrhythmia Unit, Hospital General Universitario Gregorio Marañón, Madrid, Spain (F.A., P.Á., Á.A.); Centro de Investigación e Innovación en Bioingeniería, Ci2B, Universitat Politècnica de Valencia, Valencia, Spain (J.S., L.M., A.F.); Arrhythmia Unit, Hospital Río Hortega de Valladolid and Universitario de Burgos, Valladolid-Burgos, Spain (B.H., J.G.-F.); Universitat de Valencia, Valencia, Spain (R.S.); and Department of Statistics, Hospital Universitario Central de Asturias, Oviedo, Spain (P.M.-C.)
| | - Laura Martínez
- From the Arrhythmia Unit, Hospital Universitario Central de Asturias, Oviedo, Spain (D.C., J.R.); Center for Arrhythmia Research, University of Michigan, Ann Arbor (J.J., O.B.); Arrhythmia Unit, Hospital General Universitario Gregorio Marañón, Madrid, Spain (F.A., P.Á., Á.A.); Centro de Investigación e Innovación en Bioingeniería, Ci2B, Universitat Politècnica de Valencia, Valencia, Spain (J.S., L.M., A.F.); Arrhythmia Unit, Hospital Río Hortega de Valladolid and Universitario de Burgos, Valladolid-Burgos, Spain (B.H., J.G.-F.); Universitat de Valencia, Valencia, Spain (R.S.); and Department of Statistics, Hospital Universitario Central de Asturias, Oviedo, Spain (P.M.-C.)
| | - Pablo Ávila
- From the Arrhythmia Unit, Hospital Universitario Central de Asturias, Oviedo, Spain (D.C., J.R.); Center for Arrhythmia Research, University of Michigan, Ann Arbor (J.J., O.B.); Arrhythmia Unit, Hospital General Universitario Gregorio Marañón, Madrid, Spain (F.A., P.Á., Á.A.); Centro de Investigación e Innovación en Bioingeniería, Ci2B, Universitat Politècnica de Valencia, Valencia, Spain (J.S., L.M., A.F.); Arrhythmia Unit, Hospital Río Hortega de Valladolid and Universitario de Burgos, Valladolid-Burgos, Spain (B.H., J.G.-F.); Universitat de Valencia, Valencia, Spain (R.S.); and Department of Statistics, Hospital Universitario Central de Asturias, Oviedo, Spain (P.M.-C.)
| | - José Rubín
- From the Arrhythmia Unit, Hospital Universitario Central de Asturias, Oviedo, Spain (D.C., J.R.); Center for Arrhythmia Research, University of Michigan, Ann Arbor (J.J., O.B.); Arrhythmia Unit, Hospital General Universitario Gregorio Marañón, Madrid, Spain (F.A., P.Á., Á.A.); Centro de Investigación e Innovación en Bioingeniería, Ci2B, Universitat Politècnica de Valencia, Valencia, Spain (J.S., L.M., A.F.); Arrhythmia Unit, Hospital Río Hortega de Valladolid and Universitario de Burgos, Valladolid-Burgos, Spain (B.H., J.G.-F.); Universitat de Valencia, Valencia, Spain (R.S.); and Department of Statistics, Hospital Universitario Central de Asturias, Oviedo, Spain (P.M.-C.)
| | - Benito Herreros
- From the Arrhythmia Unit, Hospital Universitario Central de Asturias, Oviedo, Spain (D.C., J.R.); Center for Arrhythmia Research, University of Michigan, Ann Arbor (J.J., O.B.); Arrhythmia Unit, Hospital General Universitario Gregorio Marañón, Madrid, Spain (F.A., P.Á., Á.A.); Centro de Investigación e Innovación en Bioingeniería, Ci2B, Universitat Politècnica de Valencia, Valencia, Spain (J.S., L.M., A.F.); Arrhythmia Unit, Hospital Río Hortega de Valladolid and Universitario de Burgos, Valladolid-Burgos, Spain (B.H., J.G.-F.); Universitat de Valencia, Valencia, Spain (R.S.); and Department of Statistics, Hospital Universitario Central de Asturias, Oviedo, Spain (P.M.-C.)
| | - Ángel Arenal
- From the Arrhythmia Unit, Hospital Universitario Central de Asturias, Oviedo, Spain (D.C., J.R.); Center for Arrhythmia Research, University of Michigan, Ann Arbor (J.J., O.B.); Arrhythmia Unit, Hospital General Universitario Gregorio Marañón, Madrid, Spain (F.A., P.Á., Á.A.); Centro de Investigación e Innovación en Bioingeniería, Ci2B, Universitat Politècnica de Valencia, Valencia, Spain (J.S., L.M., A.F.); Arrhythmia Unit, Hospital Río Hortega de Valladolid and Universitario de Burgos, Valladolid-Burgos, Spain (B.H., J.G.-F.); Universitat de Valencia, Valencia, Spain (R.S.); and Department of Statistics, Hospital Universitario Central de Asturias, Oviedo, Spain (P.M.-C.)
| | - Javier García-Fernández
- From the Arrhythmia Unit, Hospital Universitario Central de Asturias, Oviedo, Spain (D.C., J.R.); Center for Arrhythmia Research, University of Michigan, Ann Arbor (J.J., O.B.); Arrhythmia Unit, Hospital General Universitario Gregorio Marañón, Madrid, Spain (F.A., P.Á., Á.A.); Centro de Investigación e Innovación en Bioingeniería, Ci2B, Universitat Politècnica de Valencia, Valencia, Spain (J.S., L.M., A.F.); Arrhythmia Unit, Hospital Río Hortega de Valladolid and Universitario de Burgos, Valladolid-Burgos, Spain (B.H., J.G.-F.); Universitat de Valencia, Valencia, Spain (R.S.); and Department of Statistics, Hospital Universitario Central de Asturias, Oviedo, Spain (P.M.-C.)
| | - Ana Ferrer
- From the Arrhythmia Unit, Hospital Universitario Central de Asturias, Oviedo, Spain (D.C., J.R.); Center for Arrhythmia Research, University of Michigan, Ann Arbor (J.J., O.B.); Arrhythmia Unit, Hospital General Universitario Gregorio Marañón, Madrid, Spain (F.A., P.Á., Á.A.); Centro de Investigación e Innovación en Bioingeniería, Ci2B, Universitat Politècnica de Valencia, Valencia, Spain (J.S., L.M., A.F.); Arrhythmia Unit, Hospital Río Hortega de Valladolid and Universitario de Burgos, Valladolid-Burgos, Spain (B.H., J.G.-F.); Universitat de Valencia, Valencia, Spain (R.S.); and Department of Statistics, Hospital Universitario Central de Asturias, Oviedo, Spain (P.M.-C.)
| | - Rafael Sebastián
- From the Arrhythmia Unit, Hospital Universitario Central de Asturias, Oviedo, Spain (D.C., J.R.); Center for Arrhythmia Research, University of Michigan, Ann Arbor (J.J., O.B.); Arrhythmia Unit, Hospital General Universitario Gregorio Marañón, Madrid, Spain (F.A., P.Á., Á.A.); Centro de Investigación e Innovación en Bioingeniería, Ci2B, Universitat Politècnica de Valencia, Valencia, Spain (J.S., L.M., A.F.); Arrhythmia Unit, Hospital Río Hortega de Valladolid and Universitario de Burgos, Valladolid-Burgos, Spain (B.H., J.G.-F.); Universitat de Valencia, Valencia, Spain (R.S.); and Department of Statistics, Hospital Universitario Central de Asturias, Oviedo, Spain (P.M.-C.)
| | - Pablo Martínez-Camblor
- From the Arrhythmia Unit, Hospital Universitario Central de Asturias, Oviedo, Spain (D.C., J.R.); Center for Arrhythmia Research, University of Michigan, Ann Arbor (J.J., O.B.); Arrhythmia Unit, Hospital General Universitario Gregorio Marañón, Madrid, Spain (F.A., P.Á., Á.A.); Centro de Investigación e Innovación en Bioingeniería, Ci2B, Universitat Politècnica de Valencia, Valencia, Spain (J.S., L.M., A.F.); Arrhythmia Unit, Hospital Río Hortega de Valladolid and Universitario de Burgos, Valladolid-Burgos, Spain (B.H., J.G.-F.); Universitat de Valencia, Valencia, Spain (R.S.); and Department of Statistics, Hospital Universitario Central de Asturias, Oviedo, Spain (P.M.-C.)
| | - José Jalife
- From the Arrhythmia Unit, Hospital Universitario Central de Asturias, Oviedo, Spain (D.C., J.R.); Center for Arrhythmia Research, University of Michigan, Ann Arbor (J.J., O.B.); Arrhythmia Unit, Hospital General Universitario Gregorio Marañón, Madrid, Spain (F.A., P.Á., Á.A.); Centro de Investigación e Innovación en Bioingeniería, Ci2B, Universitat Politècnica de Valencia, Valencia, Spain (J.S., L.M., A.F.); Arrhythmia Unit, Hospital Río Hortega de Valladolid and Universitario de Burgos, Valladolid-Burgos, Spain (B.H., J.G.-F.); Universitat de Valencia, Valencia, Spain (R.S.); and Department of Statistics, Hospital Universitario Central de Asturias, Oviedo, Spain (P.M.-C.)
| | - Omer Berenfeld
- From the Arrhythmia Unit, Hospital Universitario Central de Asturias, Oviedo, Spain (D.C., J.R.); Center for Arrhythmia Research, University of Michigan, Ann Arbor (J.J., O.B.); Arrhythmia Unit, Hospital General Universitario Gregorio Marañón, Madrid, Spain (F.A., P.Á., Á.A.); Centro de Investigación e Innovación en Bioingeniería, Ci2B, Universitat Politècnica de Valencia, Valencia, Spain (J.S., L.M., A.F.); Arrhythmia Unit, Hospital Río Hortega de Valladolid and Universitario de Burgos, Valladolid-Burgos, Spain (B.H., J.G.-F.); Universitat de Valencia, Valencia, Spain (R.S.); and Department of Statistics, Hospital Universitario Central de Asturias, Oviedo, Spain (P.M.-C.).
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17
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Zheng Y, Wei D, Zhu X, Chen W, Fukuda K, Shimokawa H. Ventricular fibrillation mechanisms and cardiac restitutions: An investigation by simulation study on whole-heart model. Comput Biol Med 2015; 63:261-8. [DOI: 10.1016/j.compbiomed.2014.06.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 05/14/2014] [Accepted: 06/23/2014] [Indexed: 11/27/2022]
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18
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Abstract
The sequence of myocardial electrical activation during fibrillation is complex and changes with each cycle. Phase analysis represents the electrical activation-recovery process as an angle. Lines of equal phase converge at a phase singularity at the center of rotation of a reentrant wave, and the identification of reentry and tracking of reentrant wavefronts can be automated. We examine the basic ideas behind phase analysis. With the exciting prospect of using phase analysis of atrial electrograms to guide ablation in the human heart, we highlight several recent developments in preprocessing electrograms so that phase can be estimated reliably.
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Affiliation(s)
- Richard H Clayton
- Insigneo Institute for in-silico medicine and Department of Computer Science, University of Sheffield, Regent Court, 211 Portobello Street, Sheffield S1 4DP, UK.
| | - Martyn P Nash
- Auckland Bioengineering Institute and Engineering Science, University of Auckland, Uniservices House, Level 7, Room 439-715, 70 Symonds Street, Auckland 1010, New Zealand
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19
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Kazbanov IV, Clayton RH, Nash MP, Bradley CP, Paterson DJ, Hayward MP, Taggart P, Panfilov AV. Effect of global cardiac ischemia on human ventricular fibrillation: insights from a multi-scale mechanistic model of the human heart. PLoS Comput Biol 2014; 10:e1003891. [PMID: 25375999 PMCID: PMC4222598 DOI: 10.1371/journal.pcbi.1003891] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 09/03/2014] [Indexed: 11/18/2022] Open
Abstract
Acute regional ischemia in the heart can lead to cardiac arrhythmias such as ventricular fibrillation (VF), which in turn compromise cardiac output and result in secondary global cardiac ischemia. The secondary ischemia may influence the underlying arrhythmia mechanism. A recent clinical study documents the effect of global cardiac ischaemia on the mechanisms of VF. During 150 seconds of global ischemia the dominant frequency of activation decreased, while after reperfusion it increased rapidly. At the same time the complexity of epicardial excitation, measured as the number of epicardical phase singularity points, remained approximately constant during ischemia. Here we perform numerical studies based on these clinical data and propose explanations for the observed dynamics of the period and complexity of activation patterns. In particular, we study the effects on ischemia in pseudo-1D and 2D cardiac tissue models as well as in an anatomically accurate model of human heart ventricles. We demonstrate that the fall of dominant frequency in VF during secondary ischemia can be explained by an increase in extracellular potassium, while the increase during reperfusion is consistent with washout of potassium and continued activation of the ATP-dependent potassium channels. We also suggest that memory effects are responsible for the observed complexity dynamics. In addition, we present unpublished clinical results of individual patient recordings and propose a way of estimating extracellular potassium and activation of ATP-dependent potassium channels from these measurements.
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Affiliation(s)
- Ivan V Kazbanov
- Department of Physics and Astronomy, Ghent University, Ghent, Belgium
| | - Richard H Clayton
- INSIGNEO Institute for In-Silico Medicine, University of Sheffield, Sheffield, United Kingdom; Department of Computer Science, University of Sheffield, Sheffield, United Kingdom
| | - Martyn P Nash
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand; Department of Engineering Science, University of Auckland, Auckland, New Zealand
| | - Chris P Bradley
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - David J Paterson
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Martin P Hayward
- Departments of Cardiology and Cardiothoracic Surgery, University College Hospital, London, United Kingdom
| | - Peter Taggart
- Departments of Cardiology and Cardiothoracic Surgery, University College Hospital, London, United Kingdom
| | - Alexander V Panfilov
- Department of Physics and Astronomy, Ghent University, Ghent, Belgium; Moscow Institute of Physics and Technology (State University), Dolgoprudny, Moscow Region, Russia
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Krummen DE, Hayase J, Morris DJ, Ho J, Smetak MR, Clopton P, Rappel WJ, Narayan SM. Rotor stability separates sustained ventricular fibrillation from self-terminating episodes in humans. J Am Coll Cardiol 2014; 63:2712-21. [PMID: 24794115 DOI: 10.1016/j.jacc.2014.03.037] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2013] [Revised: 03/23/2014] [Accepted: 03/29/2014] [Indexed: 10/25/2022]
Abstract
OBJECTIVES This study mapped human ventricular fibrillation (VF) to define mechanistic differences between episodes requiring defibrillation versus those that spontaneously terminate. BACKGROUND VF is a leading cause of mortality; yet, episodes may also self-terminate. We hypothesized that the initial maintenance of human VF is dependent upon the formation and stability of VF rotors. METHODS We enrolled 26 consecutive patients (age 64 ± 10 years, n = 13 with left ventricular dysfunction) during ablation procedures for ventricular arrhythmias, using 64-electrode basket catheters in both ventricles to map VF prior to prompt defibrillation per the institutional review board-approved protocol. A total of 52 inductions were attempted, and 36 VF episodes were observed. Phase analysis was applied to identify biventricular rotors in the first 10 s or until VF terminated, whichever came first (11.4 ± 2.9 s to defibrillator charging). RESULTS Rotors were present in 16 of 19 patients with VF and in all patients with sustained VF. Sustained, but not self-limiting VF, was characterized by greater rotor stability: 1) rotors were present in 68 ± 17% of cycles in sustained VF versus 11 ± 18% of cycles in self-limiting VF (p < 0.001); and 2) maximum continuous rotations were greater in sustained (17 ± 11, range 7 to 48) versus self-limiting VF (1.1 ± 1.4, range 0 to 4, p < 0.001). Additionally, biventricular rotor locations in sustained VF were conserved across multiple inductions (7 of 7 patients, p = 0.025). CONCLUSIONS In patients with and without structural heart disease, the formation of stable rotors identifies individuals whose VF requires defibrillation from those in whom VF spontaneously self-terminates. Future work should define the mechanisms that stabilize rotors and evaluate whether rotor modulation may reduce subsequent VF risk.
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Affiliation(s)
- David E Krummen
- University of California San Diego, San Diego, California; Veterans Affairs San Diego Healthcare System, San Diego, California.
| | - Justin Hayase
- University of California San Diego, San Diego, California; Veterans Affairs San Diego Healthcare System, San Diego, California
| | - David J Morris
- University of California San Diego, San Diego, California; Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Jeffrey Ho
- University of California San Diego, San Diego, California; Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Miriam R Smetak
- Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Paul Clopton
- Veterans Affairs San Diego Healthcare System, San Diego, California
| | | | - Sanjiv M Narayan
- University of California San Diego, San Diego, California; Veterans Affairs San Diego Healthcare System, San Diego, California
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Such-Miquel L, Chorro FJ, Guerrero J, Trapero I, Brines L, Zarzoso M, Parra G, Soler C, del Canto I, Alberola A, Such L. Evaluación de la complejidad de la activación miocárdica durante la fibrilación ventricular. Estudio experimental. Rev Esp Cardiol 2013. [DOI: 10.1016/j.recesp.2012.08.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Evaluation of the complexity of myocardial activation during ventricular fibrillation. An experimental study. ACTA ACUST UNITED AC 2012; 66:177-84. [PMID: 24775451 DOI: 10.1016/j.rec.2012.08.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Accepted: 08/31/2012] [Indexed: 11/23/2022]
Abstract
INTRODUCTION AND OBJECTIVES An experimental model is used to analyze the characteristics of ventricular fibrillation in situations of variable complexity, establishing relationships among the data produced by different methods for analyzing the arrhythmia. METHODS In 27 isolated rabbit heart preparations studied under the action of drugs (propranolol and KB-R7943) or physical procedures (stretching) that produce different degrees of change in the complexity of myocardial activation during ventricular fibrillation, use was made of spectral, morphological, and mapping techniques to process the recordings obtained with epicardial multielectrodes. RESULTS The complexity of ventricular fibrillation assessed by mapping techniques was related to the dominant frequency, normalized spectral energy, signal regularity index, and their corresponding coefficients of variation, as well as the area of the regions of interest identified on the basis of these parameters. In the multivariate analysis, we used as independent variables the area of the regions of interest related to the spectral energy and the coefficient of variation of the energy (complexity index=-0.005×area of the spectral energy regions -2.234×coefficient of variation of the energy+1.578; P=.0001; r=0.68). CONCLUSIONS The spectral and morphological indicators and, independently, those derived from the analysis of normalized energy regions of interest provide a reliable approach to the evaluation of the complexity of ventricular fibrillation as an alternative to complex mapping techniques.
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Postrepolarization refractoriness in acute ischemia and after antiarrhythmic drug administration: Action potential duration is not always an index of the refractory period. Heart Rhythm 2012; 9:977-82. [DOI: 10.1016/j.hrthm.2012.01.021] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Indexed: 11/17/2022]
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Clayton RH, Nash MP, Bradley CP, Panfilov AV, Paterson DJ, Taggart P. Experiment-model interaction for analysis of epicardial activation during human ventricular fibrillation with global myocardial ischaemia. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2011; 107:101-11. [PMID: 21741985 DOI: 10.1016/j.pbiomolbio.2011.06.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Accepted: 06/22/2011] [Indexed: 11/25/2022]
Abstract
We describe a combined experiment-modelling framework to investigate the effects of ischaemia on the organisation of ventricular fibrillation in the human heart. In a series of experimental studies epicardial activity was recorded from 10 patients undergoing routine cardiac surgery. Ventricular fibrillation was induced by burst pacing, and recording continued during 2.5 min of global cardiac ischaemia followed by 30 s of coronary reflow. Modelling used a 2D description of human ventricular tissue. Global cardiac ischaemia was simulated by (i) decreased intracellular ATP concentration and subsequent activation of an ATP sensitive K⁺ current, (ii) elevated extracellular K⁺ concentration, and (iii) acidosis resulting in reduced magnitude of the L-type Ca²⁺ current I(Ca,L). Simulated ischaemia acted to shorten action potential duration, reduce conduction velocity, increase effective refractory period, and flatten restitution. In the model, these effects resulted in slower re-entrant activity that was qualitatively consistent with our observations in the human heart. However, the flattening of restitution also resulted in the collapse of many re-entrant waves to several stable re-entrant waves, which was different to the overall trend we observed in the experimental data. These findings highlight a potential role for other factors, such as structural or functional heterogeneity in sustaining wavebreak during human ventricular fibrillation with global myocardial ischaemia.
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Affiliation(s)
- R H Clayton
- Department of Computer Science, University of Sheffield, Regent Court, 211 Portobello S14DP, UK.
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