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Owusu-Mensah A, Berenfeld O, Audette M. ELUCIDATING THE ROLE OF THE HIS-PURKINJE SYSTEM DURING LONG QT MEDIATED ARRHYTHMIAS. ANNUAL MODELING AND SIMULATION CONFERENCE (ANNSIM). ANNUAL MODELING AND SIMULATION CONFERENCE (ONLINE) 2023; 2023:393-401. [PMID: 38074526 PMCID: PMC10705055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/31/2024]
Abstract
Mutation in the hERG gene leading to partial or complete blockade of the rapid delayed rectifier current causes Long QT Type 2 (LQT2) phenotype, the second most common form of Long QT Syndrome. However, the exact involvement of the His-Purkinje System (HPS) remains elusive. We utilized a finite element model of the rabbit ventricles integrated with a HPS to elucidate the role of HPS during LQT2-mediated arrhythmia. Following the induction of persistent reentry from an ectopic stimulus, we isolated the HPS at different time points. Moreover, we varied the coupling resistance and the number of myocytes at the Purkinje-Myocardial Junctions (PMJs) to ascertain how the junctional parameters altered reentry dynamics. Reentry was terminated with the earliest termination time for reentry coinciding with the earliest time the HPS was isolated. This observation provides evidence of direct involvement of the HPS during LQT2-mediated ventricular arrhythmia. Increasing the coupling resistance or the number of myocytes at the PMJs reduced the percentage of successful retrograde propagation during reentry. Thus, the HPS alters reentry dynamics. Our multi-scale computer modeling outcomes offer important new understandings of probable arrhythmia mechanisms under LQT2 circumstances.
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Affiliation(s)
- Anthony Owusu-Mensah
- Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, USA
| | - Omer Berenfeld
- Center for Arrhythmia Research, Internal Medicine, Biomedical Engineering and Applied Physics, University of Michigan, Ann Arbor
| | - Michel Audette
- Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, USA
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2
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Hurley M, Kaur S, Walton R, Power A, Haïssaguerre M, Bernus O, Ward ML, White E. Endocardial role in arrhythmias induced by acute ventricular stretch and the involvement of Purkinje fibres, in isolated rat hearts. Curr Res Physiol 2023; 6:100098. [PMID: 36814643 PMCID: PMC9939534 DOI: 10.1016/j.crphys.2023.100098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 01/13/2023] [Accepted: 01/25/2023] [Indexed: 02/04/2023] Open
Abstract
Purkinje fibres (PFs) play an important role in some ventricular arrhythmias and acute ventricular stretch can evoke mechanically-induced arrhythmias. We tested whether PFs and specifically TRPM4 channels, play a role in these mechanically-induced arrhythmias. Pseudo-ECGs and left ventricular (LV) activation, measured by optical mapping, were recorded in isolated, Langendorff-perfused, rat hearts. The LV endocardial surface was irrigated with experimental agents, via an indwelling catheter. The number and period of ectopic activations was measured during LV lumen inflation via an indwelling fluid-filled balloon (100 μL added over 2 s, maintained for 38 s). Mechanically-induced arrhythmias occurred during balloon inflation: they were multifocal, maximal in the first 5 s and ceased within 20 s. Optical mapping revealed activation patterns indicating PF-mediated and ectopic focal sources. Irrigation of the LV lumen with Lugol solution (IK/I2) for 10s reduced ectopics by 93% (n = 16, P < 0.001); with ablation of endocardial PFs confirmed by histology. Five min irrigation of the LV lumen with 50 μM 9-Phenanthrol, a blocker of TRPM4 channels, reduced ectopics by 39% (n = 15, P < 0.01). Immunohistochemistry confirmed that TRPM4 was more abundant in PFs than myocardium. Our results show that the endocardial surface plays an important role in these mechanically-induced ectopic activations. Ectopic activation patterns indicate a participation of PFs in these arrhythmias, with a potential involvement of TRPM4 channels, shown by the reduction of arrhythmias by 9-Phenanthrol.
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Affiliation(s)
- Miriam Hurley
- School of Biomedical Sciences, University of Leeds, Leeds, UK
| | - Sarbjot Kaur
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Richard Walton
- Université Bordeaux, INSERM Centre de recherche Cardio-Thoracique de Bordeaux, Pessac, Bordeaux, France,IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation, Bordeaux Université, Pessac, Bordeaux, France
| | - Amelia Power
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Michel Haïssaguerre
- Université Bordeaux, INSERM Centre de recherche Cardio-Thoracique de Bordeaux, Pessac, Bordeaux, France,IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation, Bordeaux Université, Pessac, Bordeaux, France,Bordeaux University Hospital (CHU), Electrophysiology and Ablation Unit, Pessac, France
| | - Olivier Bernus
- Université Bordeaux, INSERM Centre de recherche Cardio-Thoracique de Bordeaux, Pessac, Bordeaux, France,IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation, Bordeaux Université, Pessac, Bordeaux, France
| | - Marie-Louise Ward
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Ed White
- School of Biomedical Sciences, University of Leeds, Leeds, UK,Corresponding author. Garstang Building, School of Biomedical Sciences, University of Leeds, LS29JT, Leeds, UK.
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3
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Ezzeddine FM, Ward RC, Asirvatham SJ, DeSimone CV. Mapping and ablation of ventricular fibrillation substrate. J Interv Card Electrophysiol 2023:10.1007/s10840-022-01454-z. [PMID: 36598715 DOI: 10.1007/s10840-022-01454-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 12/09/2022] [Indexed: 01/05/2023]
Abstract
Ventricular fibrillation (VF) is a life-threatening arrhythmia and a common cause of sudden cardiac death (SCD). A basic understanding of its mechanistic underpinning is crucial for enhancing our knowledge to develop innovative mapping and ablation techniques for this lethal rhythm. Significant advances in our understanding of VF have been made especially in the basic science and pre-clinical experimental realms. However, these studies have not yet translated into a robust clinical approach to identify and successfully ablate both the structural and functional substrate of VF. In this review, we aim to (1) provide a conceptual framework of VF and an overview of the data supporting the spatiotemporal dynamics of VF, (2) review experimental approaches to mapping VF to elucidate drivers and substrate for maintenance with a focus on the His-Purkinje system, (3) discuss current approaches using catheter ablation to treat VF, and (4) highlight current unknowns and gaps in the field where future work is necessary to transform the clinical landscape.
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Affiliation(s)
- Fatima M Ezzeddine
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Robert Charles Ward
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Samuel J Asirvatham
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Christopher V DeSimone
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.
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4
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Hurley M, Walton R, Vigmond EJ, Haïssaguerre M, Bernus O, White E. Attenuation of stretch-induced arrhythmias following chemical ablation of Purkinje fibres, in isolated rabbit hearts. Front Physiol 2023; 14:1154157. [PMID: 37089427 PMCID: PMC10115947 DOI: 10.3389/fphys.2023.1154157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 03/23/2023] [Indexed: 04/25/2023] Open
Abstract
Purkinje fibres (PFs) play an important role in some ventricular arrhythmias and acute ventricular stretch can evoke mechanically-induced arrhythmias. We tested whether Purkinje fibres, play a role in these arrhythmias. Pseudo-ECGs were recorded in isolated, Langendorff-perfused, rabbit hearts in which the left ventricular endocardial surface was also irrigated with Tyrode, via an indwelling catheter placed in the left ventricular lumen. The number and period of ectopic activations was measured during left ventricular lumen inflation via an indwelling fluid-filled balloon (500 μL added over 2 s and maintained for 15 s in total). Mechanically-induced arrhythmias occurred in 70% of balloon inflations: they were maximal in the first 5 s and ceased within 15 s. Brief, (10 s) irrigation of the left ventricular lumen with Lugol solution (IK/I2), via the indwelling catheter, reduced inflation-induced ectopics by 98% (p < 0.05). Ablation of endocardial PFs by Lugol was confirmed by Triphenyltetrazolium Chloride staining. Optical mapping revealed the left ventricular epicardial activation patterns of ectopics could have PF-mediated and focal sources. In silico modelling predicted ectopic sources originating in the endocardial region propagate to and through the Purkinje fibres network. Acute distention-induced ectopics are multi-focal, their attenuation by Lugol, their activation patterns and in silico modelling indicate a participation of Purkinje fibres in these arrhythmias.
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Affiliation(s)
- Miriam Hurley
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Richard Walton
- INSERM Centre de recherche Cardio-Thoracique de Bordeaux, Université Bordeaux, Pessac-Bordeaux, France
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation, Bordeaux Université, Pessac-Bordeaux, France
| | - Edward J. Vigmond
- INSERM Centre de recherche Cardio-Thoracique de Bordeaux, Université Bordeaux, Pessac-Bordeaux, France
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation, Bordeaux Université, Pessac-Bordeaux, France
| | - Michel Haïssaguerre
- INSERM Centre de recherche Cardio-Thoracique de Bordeaux, Université Bordeaux, Pessac-Bordeaux, France
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation, Bordeaux Université, Pessac-Bordeaux, France
- Electrophysiology and Ablation Unit, Bordeaux University Hospital (CHU), Pessac, France
| | - Olivier Bernus
- INSERM Centre de recherche Cardio-Thoracique de Bordeaux, Université Bordeaux, Pessac-Bordeaux, France
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation, Bordeaux Université, Pessac-Bordeaux, France
| | - Ed White
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
- *Correspondence: Ed White,
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Ripplinger CM, Glukhov AV, Kay MW, Boukens BJ, Chiamvimonvat N, Delisle BP, Fabritz L, Hund TJ, Knollmann BC, Li N, Murray KT, Poelzing S, Quinn TA, Remme CA, Rentschler SL, Rose RA, Posnack NG. Guidelines for assessment of cardiac electrophysiology and arrhythmias in small animals. Am J Physiol Heart Circ Physiol 2022; 323:H1137-H1166. [PMID: 36269644 PMCID: PMC9678409 DOI: 10.1152/ajpheart.00439.2022] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Cardiac arrhythmias are a major cause of morbidity and mortality worldwide. Although recent advances in cell-based models, including human-induced pluripotent stem cell-derived cardiomyocytes (iPSC-CM), are contributing to our understanding of electrophysiology and arrhythmia mechanisms, preclinical animal studies of cardiovascular disease remain a mainstay. Over the past several decades, animal models of cardiovascular disease have advanced our understanding of pathological remodeling, arrhythmia mechanisms, and drug effects and have led to major improvements in pacing and defibrillation therapies. There exist a variety of methodological approaches for the assessment of cardiac electrophysiology and a plethora of parameters may be assessed with each approach. This guidelines article will provide an overview of the strengths and limitations of several common techniques used to assess electrophysiology and arrhythmia mechanisms at the whole animal, whole heart, and tissue level with a focus on small animal models. We also define key electrophysiological parameters that should be assessed, along with their physiological underpinnings, and the best methods with which to assess these parameters.
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Affiliation(s)
- Crystal M. Ripplinger
- 1Department of Pharmacology, University of California Davis School of Medicine, Davis, California
| | - Alexey V. Glukhov
- 2Department of Medicine, Cardiovascular Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Matthew W. Kay
- 3Department of Biomedical Engineering, The George Washington University, Washington, District of Columbia
| | - Bastiaan J. Boukens
- 4Department Physiology, University Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands,5Department of Medical Biology, University of Amsterdam, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Nipavan Chiamvimonvat
- 1Department of Pharmacology, University of California Davis School of Medicine, Davis, California,6Department of Internal Medicine, University of California Davis School of Medicine, Davis, California,7Veterans Affairs Northern California Healthcare System, Mather, California
| | - Brian P. Delisle
- 8Department of Physiology, University of Kentucky, Lexington, Kentucky
| | - Larissa Fabritz
- 9University Center of Cardiovascular Science, University Heart and Vascular Center, University Hospital Hamburg-Eppendorf with DZHK Hamburg/Kiel/Luebeck, Germany,10Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Thomas J. Hund
- 11Department of Internal Medicine, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio,12Department of Biomedical Engineering, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Bjorn C. Knollmann
- 13Vanderbilt Center for Arrhythmia Research and Therapeutics, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Na Li
- 14Department of Medicine, Baylor College of Medicine, Houston, Texas
| | - Katherine T. Murray
- 15Departments of Medicine and Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Steven Poelzing
- 16Virginia Tech Carilon School of Medicine, Center for Heart and Reparative Medicine Research, Fralin Biomedical Research Institute at Virginia Tech, Roanoke, Virginia,17Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - T. Alexander Quinn
- 18Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada,19School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Carol Ann Remme
- 20Department of Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias Amsterdam UMC Location University of Amsterdam, Amsterdam, The Netherlands
| | - Stacey L. Rentschler
- 21Cardiovascular Division, Department of Medicine, Washington University in Saint Louis, School of Medicine, Saint Louis, Missouri
| | - Robert A. Rose
- 22Department of Cardiac Sciences, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada,23Department of Physiology and Pharmacology, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Nikki G. Posnack
- 24Sheikh Zayed Institute for Pediatric Surgical Innovation, Children’s National Hospital, Washington, District of Columbia,25Department of Pediatrics, George Washington University School of Medicine, Washington, District of Columbia
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6
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Ezzeddine FM, Darlington AM, DeSimone CV, Asirvatham SJ. Catheter Ablation of Ventricular Fibrillation. Card Electrophysiol Clin 2022; 14:729-742. [PMID: 36396189 DOI: 10.1016/j.ccep.2022.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Ventricular fibrillation (VF) is a common cause of sudden cardiac death (SCD) and is unfortunately without a cure. Current therapies focus on prevention of SCD, such as implantable cardioverter-defibrillator (ICD) implantation and anti-arrhythmic agents. Significant progress has been made in improving our understanding and ability to target the triggers of VF, via advanced mapping and ablation techniques, as well as with autonomic modulation. However, the critical substrate for VF maintenance remains incompletely defined. In this review, we discuss the evidence behind the basic mechanisms of VF and review the current role of catheter ablation in patients with VF.
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Affiliation(s)
- Fatima M Ezzeddine
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street Southwest, Rochester, MN, USA
| | - Ashley M Darlington
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street Southwest, Rochester, MN, USA
| | - Christopher V DeSimone
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street Southwest, Rochester, MN, USA
| | - Samuel J Asirvatham
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street Southwest, Rochester, MN, USA.
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7
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Ezzeddine FM, Ward RC, Jiang Z, Tri JA, Agboola K, Hu T, Lodhi F, Tan NY, Ladas TP, Christopoulos G, Sugrue AM, Tolkacheva EG, Munoz FDC, McLeod CJ, Asirvatham SJ, DeSimone CV. Novel insights into the substrate involved in maintenance of ventricular fibrillation: results from continuous multipolar mapping in a canine model. J Interv Card Electrophysiol 2022:10.1007/s10840-022-01333-7. [PMID: 35948726 DOI: 10.1007/s10840-022-01333-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 08/01/2022] [Indexed: 11/27/2022]
Abstract
BACKGROUND While the triggers for ventricular fibrillation (VF) are well-known, the substrate required for its maintenance remains elusive. We have previously demonstrated dynamic spatiotemporal changes across VF from electrical induction of VF to asystole. Those data suggested that VF drivers seemed to reside in the distal RV and LV. However, signals from these areas were not recorded continuously. The aim of this study was to map these regions of significance with stationary basket electrodes from induction to asystole to provide further insights into the critical substrate for VF rhythm sustenance in canines. METHODS In six healthy canines, three multipolar basket catheters were positioned in the distal right ventricle (RV), RV outflow tract, and distal left ventricle (LV), and remained in place throughout the study. VF was induced via direct current application from an electrophysiologic catheter. Surface and intracardiac electrograms were recorded simultaneously and continuously from baseline, throughout VF, and until asystole, in order to get a complete electrophysiologic analysis of VF. Focused data analysis was also performed via two defined stages of VF: early VF (immediately after induction of VF to 10 min) and late VF (after 10 min up to VF termination and asystole). RESULTS VF was continuously mapped for a mean duration of 54 ± 9 min (range 42-70 min). Immediately after initiation of VF in the early phase, the distal LV region appeared to drive the maintenance of VF. Towards the terminal stage of VF, the distal RV region appeared to be responsible for VF persistence. In all canines, we noted local termination of VF in the LV, while VF on surface ECG continued; conversely, subsequent spontaneous termination of VF in the RV was associated with termination of VF on surface ECG into a ventricular escape rhythm. Continuous mapping of VF showed trends towards an increase in peak-to-peak ventricular electrogram cycle length (p = 0.06) and a decrease in the ventricular electrogram amplitude (p = 0.06) after 40 min. Once we could no longer discern surface QRS activity, we demonstrated local ventricular myocardial capture in both the RV and LV but could not reinitiate sustained VF despite aggressive ventricular burst pacing. CONCLUSIONS This study describes the evolution of VF from electrical initiation to spontaneous VF termination without hemodynamic support in healthy canines. These data are hypothesis-generating and suggest that critical substrate for VF maintenance may reside in both the distal RV and LV depending on stage of VF. Further studies are needed to replicate these findings with hemodynamic support and to translate such findings into clinical practice. Ventricular fibrillation maintenance may be dependent on critical structures in the distal RV. ECG: electrocardiogram; LV: left ventricle; RV: right ventricle; RVOT: right ventricular outflow tract; VF: ventricular fibrillation.
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Affiliation(s)
- Fatima M Ezzeddine
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Robert C Ward
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Zhi Jiang
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Jason A Tri
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Kolade Agboola
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Tiffany Hu
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Fahad Lodhi
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Nicholas Y Tan
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Thomas P Ladas
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Georgios Christopoulos
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Alan M Sugrue
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Elena G Tolkacheva
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA
| | - Freddy Del-Carpio Munoz
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | | | - Samuel J Asirvatham
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
- Department of Pediatric and Adolescent Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Christopher V DeSimone
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.
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8
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Shah AR, Khan MS, Lange M, Hirahara AM, Stoddard G, Ranjan R, Dosdall DJ. During Early VF in Rabbit Hearts, His Bundle Pacing is Less Effective Than Working Myocardial Pacing in Modulating Left Ventricular Activation Rates. Cardiovasc Eng Technol 2022; 13:452-465. [PMID: 34816378 PMCID: PMC9124730 DOI: 10.1007/s13239-021-00593-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 11/03/2021] [Indexed: 11/25/2022]
Abstract
PURPOSE The potential of pacing and capturing the His-Purkinje system (HPS) to synchronize VF wavefronts is not known even though the HPS is thought to be electrically linked during VF. In this study the effect of selective His Bundle (HB) pacing was compared with nearby working myocardial (WM) pacing on the left ventricular (LV) endocardial activation rates. METHODS Rabbit hearts (n = 9) were explanted and Langendorff perfused. Electrodes directly on the HB were identified and paced subsequently using an electrode array. The WM was paced through a silver wire inserted in the right ventricular septal wall. After VF was induced, the HB was paced at rates faster than the intrinsic HB activation rate (n = 18 episodes) and also at rates faster than the LV activation rate (n = 16). A basket array inserted in the LV was used to record electrograms before and during each pacing episode. Activation rates at five LV electrodes each from the earliest and latest activating sinus rhythm regions were analyzed before and during pacing. RESULTS Both HB and WM pacing reduced LV activation rates during pacing, but WM pacing was more effective (p < 0.005). WM pacing events were more effective (p < 0.05) in reducing LV activation rates than HB pacing in episodes which were faster than LV activation rates. CONCLUSION This study provides evidence that during early VF in rabbit hearts, the HPS cannot be driven to effectively modulate the LV activation rates.
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Affiliation(s)
- Ankur R. Shah
- Department of Biomedical Engineering, The University of Utah, Salt Lake City, UT 84112, USA., Nora Eccles Harrison Cardiovascular Research and Training Institute, The University of Utah, Salt Lake City, UT 84112, USA
| | - Muhammad S. Khan
- Nora Eccles Harrison Cardiovascular Research and Training Institute, The University of Utah, Salt Lake City, UT 84112, USA
| | - Matthias Lange
- Nora Eccles Harrison Cardiovascular Research and Training Institute, The University of Utah, Salt Lake City, UT 84112, USA
| | - Annie M. Hirahara
- Department of Biomedical Engineering, The University of Utah, Salt Lake City, UT 84112, USA., Nora Eccles Harrison Cardiovascular Research and Training Institute, The University of Utah, Salt Lake City, UT 84112, USA
| | - Gregory Stoddard
- Division of Epidemiology, School of Medicine, The University of Utah, Salt Lake City, UT 84112, USA
| | - Ravi Ranjan
- Department of Biomedical Engineering, The University of Utah, Salt Lake City, UT 84112, USA., Nora Eccles Harrison Cardiovascular Research and Training Institute, The University of Utah, Salt Lake City, UT 84112, USA., Division of Cardiovascular Medicine, Department of Internal Medicine, The University of Utah, Salt Lake City, UT 84112, USA
| | - Derek J. Dosdall
- Department of Biomedical Engineering, The University of Utah, Salt Lake City, UT 84112, USA., Nora Eccles Harrison Cardiovascular Research and Training Institute, The University of Utah, Salt Lake City, UT 84112, USA., Division of Cardiovascular Medicine, Department of Internal Medicine, The University of Utah, Salt Lake City, UT 84112, USA., Division of Cardiothoracic Surgery, Department of Surgery, The University of Utah, Salt Lake City, UT 84112, USA.,Correspondence: Dr. Derek J. Dosdall, Associate Professor of Surgery, Division of Cardiothoracic Surgery, School of Medicine, The University of Utah, Salt Lake City, UT 84112, / Ph: (+1) 801-587-2036
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9
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Anderson RD, Massé S, Asta J, Lai PFH, Chakraborty P, Azam MA, Downar E, Nanthakumar K. Role of Purkinje-Muscle Junction in Early Ventricular Fibrillation in a Porcine Model: Beyond the Trigger Concept. Pacing Clin Electrophysiol 2022; 45:742-751. [PMID: 35067947 DOI: 10.1111/pace.14453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 01/01/2022] [Accepted: 01/14/2022] [Indexed: 11/28/2022]
Abstract
BACKGROUND The role of the Purkinje network in triggering ventricular fibrillation (VF) has been studied, however, its involvement after onset and in early maintenance of VF is controversial. AIM We studied the role of the Purkinje-muscle junctions (PMJ) on epicardial-endocardial activation gradients during early VF. METHODS In a healthy, porcine, beating-heart Langendorff model [control, n = 5; ablation, n = 5], simultaneous epicardial-endocardial dominant frequent mapping was used (224 unipolar electrograms) to calculate activation rate gradients during the onset and early phase of VF. Selective Purkinje ablation was performed using Lugol's solution, followed by VF re-induction and mapping and finally, histological evaluation. RESULTS Epicardial activation rates were faster than endocardial rates for both onset and early VF. After PMJ ablation, activation rates decreased epicardially and endocardially for both onset and early VF [Epi: 9.7±0.2 to 8.3±0.2 Hz (P<0.0001) and 10.9±0.4 to 8.8±0.3 Hz (P<0.0001), respectively; Endo: 8.2 ± 0.3 Hz to 7.4 ± 0.2 Hz (P<0.0001) and 7.0 ± 0.4 Hz to 6.6 ± 0.3 Hz (P = 0.0002), respectively]. In controls, epicardial-endocardial activation rate gradients during onset and early VF were 1.7±0.3 Hz and 4.5±0.4 Hz (P<0.001), respectively. After endocardial ablation of PMJs, these gradients were reduced to 0.9±0.3 Hz (onset VF, P<0.001) and to 2.2±0.3 Hz (early VF, P<0.001). Endocardial-epicardial Purkinje fibre arborization and selective Purkinje fibre extinction after only endocardial ablation (not with epicardial ablation) was confirmed on histological analysis. CONCLUSIONS Beyond the trigger paradigm, PMJs determine activation rate gradients during onset and during early maintenance of VF. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Robert D Anderson
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Canada
| | - Stéphane Massé
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Canada
| | - John Asta
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Canada
| | - Patrick F H Lai
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Canada
| | - Praloy Chakraborty
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Canada
| | - Mohammed Ali Azam
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Canada
| | - Eugene Downar
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Canada
| | - Kumaraswamy Nanthakumar
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Canada
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10
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Shibata N, Inada S, Nakazawa K, Ashihara T, Tomii N, Yamazaki M, Honjo H, Seno H, Sakuma I. Mechanism of Ventricular Fibrillation: Current Status and Problems. ADVANCED BIOMEDICAL ENGINEERING 2022. [DOI: 10.14326/abe.11.117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Affiliation(s)
- Nitaro Shibata
- Department of Cardiology, Shinjuku Mitsui Building Clinic
| | - Shin Inada
- Faculty of Medical Science Technology, Morinomiya University of Medical Sciences
| | - Kazuo Nakazawa
- Faculty of Medical Science Technology, Morinomiya University of Medical Sciences
| | - Takashi Ashihara
- Department of Medical Informatics and Biomedical Engineering, Shiga University of Medical Science
| | - Naoki Tomii
- Department of Precision Engineering, The University of Tokyo
| | | | - Haruo Honjo
- Health Promotion Division, Toyota Autobody Co. Ltd
| | - Hiroshi Seno
- Department of Precision Engineering, The University of Tokyo
| | - Ichiro Sakuma
- Medical Device Development and Regulation Research Center, The University of Tokyo
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11
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Analysis of vulnerability to reentry in acute myocardial ischemia using a realistic human heart model. Comput Biol Med 2021; 141:105038. [PMID: 34836624 DOI: 10.1016/j.compbiomed.2021.105038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 10/25/2021] [Accepted: 11/12/2021] [Indexed: 11/21/2022]
Abstract
Electrophysiological alterations of the myocardium caused by acute ischemia constitute a pro-arrhythmic substrate for the generation of potentially lethal arrhythmias. Experimental evidence has shown that the main components of acute ischemia that induce these electrophysiological alterations are hyperkalemia, hypoxia (or anoxia in complete artery occlusion), and acidosis. However, the influence of each ischemic component on the likelihood of reentry is not completely established. Moreover, the role of the His-Purkinje system (HPS) in the initiation and maintenance of arrhythmias is not completely understood. In the present work, we investigate how the three components of ischemia affect the vulnerable window (VW) for reentry using computational simulations. In addition, we analyze the role of the HPS on arrhythmogenesis. A 3D biventricular/torso human model that includes a realistic geometry of the central and border ischemic zones with one of the most electrophysiologically detailed model of ischemia to date, as well as a realistic cardiac conduction system, were used to assess the VW for reentry. Four scenarios of ischemic severity corresponding to different minutes after coronary artery occlusion were simulated. Our results suggest that ischemic severity plays an important role in the generation of reentries. Indeed, this is the first 3D simulation study to show that ventricular arrhythmias could be generated under moderate ischemic conditions, but not in mild and severe ischemia. Moreover, our results show that anoxia is the ischemic component with the most significant effect on the width of the VW. Thus, a change in the level of anoxia from moderate to severe leads to a greater increment in the VW (40 ms), in comparison with the increment of 20 ms and 35 ms produced by the individual change in the level of hyperkalemia and acidosis, respectively. Finally, the HPS was a necessary element for the generation of approximately 17% of reentries obtained. The retrograde conduction from the myocardium to HPS in the ischemic region, conduction blocks in discrete sections of the HPS, and the degree of ischemia affecting Purkinje cells, are suggested as mechanisms that favor the generation of ventricular arrhythmias.
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12
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Tan NY, Christopoulos G, Ladas TP, Jiang Z, Sugrue AM, Tri JA, Tolkacheva EG, Del-Carpio Munoz F, McLeod CJ, Asirvatham SJ, DeSimone CV. Regional and Temporal Variation of Ventricular and Conduction Tissue Activity During Ventricular Fibrillation in Canines. Circ Arrhythm Electrophysiol 2021; 14:e010281. [PMID: 34665643 DOI: 10.1161/circep.121.010281] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Nicholas Y Tan
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester (N.T., G.C., T.P.L., Z.J., A.M.S., J.A.T., F.D.-C.M., S.J.A., C.V.D.)
| | - Georgios Christopoulos
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester (N.T., G.C., T.P.L., Z.J., A.M.S., J.A.T., F.D.-C.M., S.J.A., C.V.D.)
| | - Thomas P Ladas
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester (N.T., G.C., T.P.L., Z.J., A.M.S., J.A.T., F.D.-C.M., S.J.A., C.V.D.)
| | - Zhi Jiang
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester (N.T., G.C., T.P.L., Z.J., A.M.S., J.A.T., F.D.-C.M., S.J.A., C.V.D.)
| | - Alan M Sugrue
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester (N.T., G.C., T.P.L., Z.J., A.M.S., J.A.T., F.D.-C.M., S.J.A., C.V.D.)
| | - Jason A Tri
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester (N.T., G.C., T.P.L., Z.J., A.M.S., J.A.T., F.D.-C.M., S.J.A., C.V.D.)
| | - Elena G Tolkacheva
- Department of Biomedical Engineering, University of Minnesota, Minneapolis (E.G.T.)
| | - Freddy Del-Carpio Munoz
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester (N.T., G.C., T.P.L., Z.J., A.M.S., J.A.T., F.D.-C.M., S.J.A., C.V.D.)
| | | | - Samuel J Asirvatham
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester (N.T., G.C., T.P.L., Z.J., A.M.S., J.A.T., F.D.-C.M., S.J.A., C.V.D.)
| | - Christopher V DeSimone
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester (N.T., G.C., T.P.L., Z.J., A.M.S., J.A.T., F.D.-C.M., S.J.A., C.V.D.)
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13
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Noheria A, Anderson J. Advances in Mapping and Ablation of Ventricular Fibrillation. CURRENT TREATMENT OPTIONS IN CARDIOVASCULAR MEDICINE 2021. [DOI: 10.1007/s11936-021-00899-1] [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: 11/24/2022]
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14
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Short coupled torsade de pointes: Critical timing of the ventricular premature beats. J Electrocardiol 2021; 65:69-72. [PMID: 33549989 DOI: 10.1016/j.jelectrocard.2021.01.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 01/08/2021] [Accepted: 01/11/2021] [Indexed: 11/20/2022]
Abstract
In this case report, we describe a 73 year old female with structuraly normal heart that developed shortcoupled torsades de pointes (TdP) resulting in an electrical storm unresponsible to several antiarrhythmic drugs, but fully controlled with verapamil. The critical timing of the ventricular premature beats that initiated TdP corresponded to those that occurred at the peak of the previous T wave. This behavior differentiates this entity from other forms of malignant ventricular arrhythmias in patients with structurally normal heart. It is imperative that the clinical set-up and unique electrocardiographic fingerprint of this unusual malignant entity be assiduously recognized since verapamil can be life-saving in this condition.
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15
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Hasegawa T, Nogami A, Aonuma K, Ieda M. Termination of long-duration ventricular fibrillation by catheter ablation. HeartRhythm Case Rep 2020; 6:955-959. [PMID: 33365248 PMCID: PMC7749215 DOI: 10.1016/j.hrcr.2020.10.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Tomoaki Hasegawa
- Department of Cardiology, Hitachi General Hospital, Hitachi, Japan
| | - Akihiko Nogami
- Department of Cardiology, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Kazutaka Aonuma
- Department of Cardiology, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Masaki Ieda
- Department of Cardiology, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
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16
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Kim Y, Chen S, Ernst S, Guzman CE, Han S, Kalarus Z, Labadet C, Lin Y, Lo L, Nogami A, Saad EB, Sapp J, Sticherling C, Tilz R, Tung R, Kim YG, Stiles MK. 2019 APHRS expert consensus statement on three-dimensional mapping systems for tachycardia developed in collaboration with HRS, EHRA, and LAHRS. J Arrhythm 2020; 36:215-270. [PMID: 32256872 PMCID: PMC7132207 DOI: 10.1002/joa3.12308] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Accepted: 01/20/2020] [Indexed: 12/24/2022] Open
Affiliation(s)
- Young‐Hoon Kim
- Department of Internal MedicineArrhythmia CenterKorea University Medicine Anam HospitalSeoulRepublic of Korea
| | - Shih‐Ann Chen
- Division of CardiologyDepartment of MedicineTaipei Veterans General HospitalTaipeiROC
| | - Sabine Ernst
- Department of CardiologyRoyal Brompton and Harefield HospitalImperial College LondonLondonUK
| | | | - Seongwook Han
- Division of CardiologyDepartment of Internal MedicineKeimyung University School of MedicineDaeguRepublic of Korea
| | - Zbigniew Kalarus
- Department of CardiologyMedical University of SilesiaKatowicePoland
| | - Carlos Labadet
- Cardiology DepartmentArrhythmias and Electrophysiology ServiceClinica y Maternidad Suizo ArgentinaBuenos AiresArgentina
| | - Yenn‐Jian Lin
- Division of CardiologyDepartment of MedicineTaipei Veterans General HospitalTaipeiROC
| | - Li‐Wei Lo
- Division of CardiologyDepartment of MedicineTaipei Veterans General HospitalTaipeiROC
| | - Akihiko Nogami
- Department of CardiologyFaculty of MedicineUniversity of TsukubaTsukubaJapan
| | - Eduardo B. Saad
- Center for Atrial FibrillationHospital Pro‐CardiacoRio de JaneiroBrazil
| | - John Sapp
- Division of CardiologyDepartment of MedicineQEII Health Sciences CentreDalhousie UniversityHalifaxNSCanada
| | | | - Roland Tilz
- Medical Clinic II (Department of Cardiology, Angiology and Intensive Care Medicine)University Hospital Schleswig‐Holstein (UKSH) – Campus LuebeckLuebeckGermany
| | - Roderick Tung
- Center for Arrhythmia CarePritzker School of MedicineUniversity of Chicago MedicineChicagoILUSA
| | - Yun Gi Kim
- Department of Internal MedicineArrhythmia CenterKorea University Medicine Anam HospitalSeoulRepublic of Korea
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17
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Sugrue A, Vaidya VR, Livia C, Padmanabhan D, Abudan A, Isath A, Witt T, DeSimone CV, Stalboerger P, Kapa S, Asirvatham SJ, McLeod CJ. Feasibility of selective cardiac ventricular electroporation. PLoS One 2020; 15:e0229214. [PMID: 32084220 PMCID: PMC7034868 DOI: 10.1371/journal.pone.0229214] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 01/31/2020] [Indexed: 12/18/2022] Open
Abstract
Introduction The application of brief high voltage electrical pulses to tissue can lead to an irreversible or reversible electroporation effect in a cell-specific manner. In the management of ventricular arrhythmias, the ability to target different tissue types, specifically cardiac conduction tissue (His-Purkinje System) vs. cardiac myocardium would be advantageous. We hypothesize that pulsed electric fields (PEFs) can be applied safely to the beating heart through a catheter-based approach, and we tested whether the superficial Purkinje cells can be targeted with PEFs without injury to underlying myocardial tissue. Methods In an acute (n = 5) and chronic canine model (n = 6), detailed electroanatomical mapping of the left ventricle identified electrical signals from myocardial and overlying Purkinje tissue. Electroporation was effected via percutaneous catheter-based Intracardiac bipolar current delivery in the anesthetized animal. Repeat Intracardiac electrical mapping of the heart was performed at acute and chronic time points; followed by histological analysis to assess effects. Results PEF demonstrated an acute dose-dependent functional effect on Purkinje, with titration of pulse duration and/or voltage associated with successful acute Purkinje damage. Electrical conduction in the insulated bundle of His (n = 2) and anterior fascicle bundle (n = 2), was not affected. At 30 days repeat cardiac mapping demonstrated resilient, normal electrical conduction throughout the targeted area with no significant change in myocardial amplitude (pre 5.9 ± 1.8 mV, 30 days 5.4 ± 1.2 mV, p = 0.92). Histopathological analysis confirmed acute Purkinje fiber targeting, with chronic studies showing normal Purkinje fibers, with minimal subendocardial myocardial fibrosis. Conclusion PEF provides a novel, safe method for non-thermal acute modulation of the Purkinje fibers without significant injury to the underlying myocardium. Future optimization of this energy delivery is required to optimize conditions so that selective electroporation can be utilized in humans the treatment of cardiac disease.
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Affiliation(s)
- Alan Sugrue
- Division of Heart Rhythm Services, Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, United States of America
| | - Vaibhav R. Vaidya
- Division of Heart Rhythm Services, Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, United States of America
| | - Christopher Livia
- Department of Cardiovascular Medicine and Department of Molecular Pharmacology and Experimental Therapeutics, Center for Regenerative Medicine, Mayo Clinic, Rochester, MN, United States of America
| | - Deepak Padmanabhan
- Division of Heart Rhythm Services, Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, United States of America
| | - Anas Abudan
- Division of Heart Rhythm Services, Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, United States of America
| | - Ameesh Isath
- Division of Heart Rhythm Services, Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, United States of America
| | - Tyra Witt
- Department of Cardiovascular Medicine and Department of Molecular Pharmacology and Experimental Therapeutics, Center for Regenerative Medicine, Mayo Clinic, Rochester, MN, United States of America
| | - Christopher V. DeSimone
- Division of Heart Rhythm Services, Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, United States of America
| | - Paul Stalboerger
- Department of Cardiovascular Medicine and Department of Molecular Pharmacology and Experimental Therapeutics, Center for Regenerative Medicine, Mayo Clinic, Rochester, MN, United States of America
| | - Suraj Kapa
- Division of Heart Rhythm Services, Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, United States of America
| | - Samuel J. Asirvatham
- Division of Heart Rhythm Services, Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, United States of America
- Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN, United States of America
| | - Christopher J. McLeod
- Division of Heart Rhythm Services, Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, United States of America
- * E-mail:
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18
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DeSimone CV, Asirvatham SJ. Purkinje tissue modification and ventricular fibrillation. Pacing Clin Electrophysiol 2019; 42:1291-1293. [PMID: 31407803 DOI: 10.1111/pace.13781] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 08/11/2019] [Indexed: 11/27/2022]
Affiliation(s)
| | - Samuel J Asirvatham
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota.,Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota
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19
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Imnadze G, Zerm T. Prevention of ventricular fibrillation through de-networking of the Purkinje system: Proof-of-Concept Paper on the Substrate Modification of the Purkinje Network. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2019; 42:1285-1290. [PMID: 31424573 PMCID: PMC6852399 DOI: 10.1111/pace.13782] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 07/02/2019] [Accepted: 07/18/2019] [Indexed: 01/01/2023]
Abstract
Introduction Sudden cardiac death from ventricular fibrillation (VF) remains a major health problem worldwide. Currently, there are limited treatment options available to patients who suffer from episodes of VF. Because Purkinje fibers have been implicated as a source of initiation of VF, we are presenting the first paper of a series highlighting the promising results of substrate modulation through “De‐Networking” of the Purkinje system preventing VF in patients without an alternative ablation strategy. Methods and Results We studied 10 consecutive patients (two female) all but one implanted with an ICD with documented VF or fast polymorphic Ventricular tachycardia (VT) (five patients without history of structural heart disease, two with ischemic cardiomyopathy, one with hypertrophic obstructive cardiomyopathy, one with dilated cardiomyopathy, and one with aortic valve disease). After 3D electroanatomical mapping, the left bundle branch (LBB) and left ventricular Purkinje potentials were annotated creating a virtual triangle with the apex formed by the distal LBB and the base by the most distal Purkinje potentials. Linear radiofrequency catheter ablation at the base of the triangle was performed, followed by ablation within the virtual triangle sparing the LBB and both fascicles (“de‐networking”). All patients were treated without complications. During 1‐year follow‐up, only 2/10(20%) patients experienced recurrence in form of a single episode of polymorphic VT/VF. Conclusion Catheter ablation of VF through “de‐networking” of the Purkinje system in patients without overt arrhythmia substrate or trigger appears safe and effective and will require further study in a larger patient cohort.
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Affiliation(s)
- Guram Imnadze
- Heart and Diabetes Center North Rhine-Westphalia, Clinic of Arrhythmia Magnagement, Bad Oeynhausen, Nordrhein-Westfalen, DE.,Ruhr-Universitat Bochum Medizinische Fakultat, Arrhythmia Management, Bochum, Nordrhein-Westfalen, DE.,Department of Arrhythmia Management, Klinikum Osnabrueck, Osnabrueck, Germany
| | - Thomas Zerm
- Electrophysiology Department, Albertinen Hospital, Academic Teaching Hospital of the University of Hamburg - Eppendorf, Hamburg, Germany
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20
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Caluori G, Wojtaszczyk A, Yasin O, Pesl M, Wolf J, Belaskova S, Crha M, Sugrue A, Vaidya VR, Naksuk N, DeSimone CV, Killu AM, Padmanabhan D, Asirvatham SJ, Stárek Z. Comparing the incidence of ventricular arrhythmias during epicardial ablation in swine versus canine models. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2019; 42:862-867. [PMID: 30989679 DOI: 10.1111/pace.13698] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 03/14/2019] [Accepted: 04/11/2019] [Indexed: 01/13/2023]
Abstract
BACKGROUND Choosing the appropriate animal model for development of novel technologies requires an understanding of anatomy and physiology of these different models. There are little data about the characteristics of different animal models for the study of technologies used for epicardial ablation. We aimed to compare the incidence of ventricular arrhythmias during epicardial radiofrequency ablation between swine and canine models using novel epicardial ablation catheters. METHODS We conducted a retrospective study using data obtained from epicardial ablation experiments performed on swine (Sus Scrofa) and canine (Canis familiaris) models. We compared the incidence of ventricular arrhythmias during ablation between swine and canine using multivariate regression analysis. Six swine and six canine animals underwent successful epicardial radiofrequency ablation. A total of 103 ablation applications were recorded. RESULTS Ventricular arrhythmias requiring cardioversion occurred in 13.11% of radiofrequency ablation applications in swine and 9.75% in canine (relative risk: 117.6%, 95% confidence interval [CI]: 83.97-164.69, animal-based odds ratio [OR]: .55, 95% CI: .23-61.33; P = .184). When adjusting for application position, duration of ablation and power, the odds of developing potentially lethal ventricular arrhythmia in swine increased significantly compared to canine (OR: 3.60, 95% CI: 1.35-9.55; P = .010). CONCLUSIONS The swine myocardium is more susceptible to developing ventricular arrhythmias compared to canine model during epicardial ablation. This issue should be carefully considered in future studies.
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Affiliation(s)
- Guido Caluori
- International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic.,CEITEC, Masaryk University, Brno, Czech Republic
| | - Adam Wojtaszczyk
- International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic.,3rd Department of Cardiology, School of Medicine with the Division of Dentistry in Zabrze, Medical University of Silesia, Katowice, Poland
| | - Omar Yasin
- Division of Cardiovascular Disease, Mayo Clinic, Rochester, Minnesota
| | - Martin Pesl
- International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic.,First Department of Internal Medicine/Cardioangiology, St. Anne´s Hospital, Masaryk University, Brno, Czech Republic.,Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Jiří Wolf
- International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic
| | - Silvie Belaskova
- International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic
| | - Michal Crha
- University of Veterinary and Pharmaceutical Sciences, Brno, Czech Republic
| | - Alan Sugrue
- Division of Cardiovascular Disease, Mayo Clinic, Rochester, Minnesota
| | - Vaibhav R Vaidya
- Division of Cardiovascular Disease, Mayo Clinic, Rochester, Minnesota
| | - Niyada Naksuk
- Division of Cardiovascular Disease, Mayo Clinic, Rochester, Minnesota
| | | | - Ammar M Killu
- Division of Cardiovascular Disease, Mayo Clinic, Rochester, Minnesota
| | | | - Samuel J Asirvatham
- Division of Cardiovascular Disease, Mayo Clinic, Rochester, Minnesota.,Department of Pediatrics and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota
| | - Zdeněk Stárek
- International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic.,First Department of Internal Medicine/Cardioangiology, St. Anne´s Hospital, Masaryk University, Brno, Czech Republic
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21
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Anderson RD, Kumar S, Kalman JM, Sanders P, Sacher F, Hocini M, Jais P, Haïsaguerre M, Lee G. Catheter Ablation of Ventricular Fibrillation. Heart Lung Circ 2019; 28:110-122. [DOI: 10.1016/j.hlc.2018.09.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 08/29/2018] [Accepted: 09/05/2018] [Indexed: 10/28/2022]
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22
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Cheniti G, Vlachos K, Meo M, Puyo S, Thompson N, Denis A, Duchateau J, Takigawa M, Martin C, Frontera A, Kitamura T, Lam A, Bourier F, Klotz N, Derval N, Sacher F, Jais P, Dubois R, Hocini M, Haissaguerre M. Mapping and Ablation of Idiopathic Ventricular Fibrillation. Front Cardiovasc Med 2018; 5:123. [PMID: 30280100 PMCID: PMC6153961 DOI: 10.3389/fcvm.2018.00123] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Accepted: 08/20/2018] [Indexed: 01/30/2023] Open
Abstract
Idiopathic ventricular fibrillation (IVF) is the main cause of unexplained sudden cardiac death, particularly in young patients under the age of 35. IVF is a diagnosis of exclusion in patients who have survived a VF episode without any identifiable structural or metabolic causes despite extensive diagnostic testing. Genetic testing allows identification of a likely causative mutation in up to 27% of unexplained sudden deaths in children and young adults. In the majority of cases, VF is triggered by PVCs that originate from the Purkinje network. Ablation of VF triggers in this setting is associated with high rates of acute success and long-term freedom from VF recurrence. Recent studies demonstrate that a significant subset of IVF defined by negative comprehensive investigations, demonstrate in fact subclinical structural alterations. These localized myocardial alterations are identified by high density electrogram mapping, are of small size and are mainly located in the epicardium. As reentrant VF drivers are often colocated with regions of abnormal electrograms, this localized substrate can be shown to be mechanistically linked with VF. Such areas may represent an important target for ablation.
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Affiliation(s)
- Ghassen Cheniti
- Electrophysiology and Ablation Unit, Bordeaux University Hospital (CHU), Pessac, France.,IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux Université, Bordeaux, France.,Department of Cardiology, Sahloul Hospital, Universite de Sousse, Sousse, Tunisia
| | - Konstantinos Vlachos
- Electrophysiology and Ablation Unit, Bordeaux University Hospital (CHU), Pessac, France.,IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux Université, Bordeaux, France
| | - Marianna Meo
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux Université, Bordeaux, France
| | - Stephane Puyo
- Electrophysiology and Ablation Unit, Bordeaux University Hospital (CHU), Pessac, France.,IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux Université, Bordeaux, France
| | - Nathaniel Thompson
- Electrophysiology and Ablation Unit, Bordeaux University Hospital (CHU), Pessac, France.,IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux Université, Bordeaux, France
| | - Arnaud Denis
- Electrophysiology and Ablation Unit, Bordeaux University Hospital (CHU), Pessac, France.,IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux Université, Bordeaux, France
| | - Josselin Duchateau
- Electrophysiology and Ablation Unit, Bordeaux University Hospital (CHU), Pessac, France.,IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux Université, Bordeaux, France
| | - Masateru Takigawa
- Electrophysiology and Ablation Unit, Bordeaux University Hospital (CHU), Pessac, France.,IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux Université, Bordeaux, France
| | - Claire Martin
- Electrophysiology and Ablation Unit, Bordeaux University Hospital (CHU), Pessac, France.,IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux Université, Bordeaux, France.,Department of Cardiology, Royal Papworth Hospital NHS Foundation Trust, Cambridge, United Kingdom
| | - Antonio Frontera
- Electrophysiology and Ablation Unit, Bordeaux University Hospital (CHU), Pessac, France.,IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux Université, Bordeaux, France
| | - Takeshi Kitamura
- Electrophysiology and Ablation Unit, Bordeaux University Hospital (CHU), Pessac, France.,IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux Université, Bordeaux, France
| | - Anna Lam
- Electrophysiology and Ablation Unit, Bordeaux University Hospital (CHU), Pessac, France.,IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux Université, Bordeaux, France
| | - Felix Bourier
- Electrophysiology and Ablation Unit, Bordeaux University Hospital (CHU), Pessac, France.,IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux Université, Bordeaux, France
| | - Nicolas Klotz
- Electrophysiology and Ablation Unit, Bordeaux University Hospital (CHU), Pessac, France.,IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux Université, Bordeaux, France
| | - Nicolas Derval
- Electrophysiology and Ablation Unit, Bordeaux University Hospital (CHU), Pessac, France.,IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux Université, Bordeaux, France
| | - Frederic Sacher
- Electrophysiology and Ablation Unit, Bordeaux University Hospital (CHU), Pessac, France.,IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux Université, Bordeaux, France
| | - Pierre Jais
- Electrophysiology and Ablation Unit, Bordeaux University Hospital (CHU), Pessac, France.,IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux Université, Bordeaux, France
| | - Remi Dubois
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux Université, Bordeaux, France
| | - Meleze Hocini
- Electrophysiology and Ablation Unit, Bordeaux University Hospital (CHU), Pessac, France.,IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux Université, Bordeaux, France
| | - Michel Haissaguerre
- Electrophysiology and Ablation Unit, Bordeaux University Hospital (CHU), Pessac, France.,IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux Université, Bordeaux, France
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23
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Livia C, Sugrue A, Witt T, Polkinghorne MD, Maor E, Kapa S, Lehmann HI, DeSimone CV, Behfar A, Asirvatham SJ, McLeod CJ. Elimination of Purkinje Fibers by Electroporation Reduces Ventricular Fibrillation Vulnerability. J Am Heart Assoc 2018; 7:e009070. [PMID: 30371233 PMCID: PMC6201470 DOI: 10.1161/jaha.118.009070] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 06/21/2018] [Indexed: 12/18/2022]
Abstract
Background The Purkinje network appears to play a pivotal role in the triggering as well as maintenance of ventricular fibrillation. Irreversible electroporation ( IRE ) using direct current has shown promise as a nonthermal ablation modality in the heart, but its ability to target and ablate the Purkinje tissue is undefined. Our aim was to investigate the potential for selective ablation of Purkinje/fascicular fibers using IRE . Methods and Results In an ex vivo Langendorff model of canine heart (n=8), direct current was delivered in a unipolar manner at various dosages from 750 to 2500 V, in 10 pulses with a 90-μs duration at a frequency of 1 Hz. The window of ventricular fibrillation vulnerability was assessed before and after delivery of electroporation energy using a shock on T-wave method. IRE consistently eradicated all Purkinje potentials at voltages between 750 and 2500 V (minimum field strength of 250-833 V/cm). The ventricular electrogram amplitude was only minimally reduced by ablation: 0.6±2.3 mV ( P=0.03). In 4 hearts after IRE delivery, ventricular fibrillation could not be reinduced. At baseline, the lower limit of vulnerability to ventricular fibrillation was 1.8±0.4 J, and the upper limit of vulnerability was 19.5±3.0 J. The window of vulnerability was 17.8±2.9 J. Delivery of electroporation energy significantly reduced the window of vulnerability to 5.7±2.9 J ( P=0.0003), with a postablation lower limit of vulnerability=7.3±2.63 J, and the upper limit of vulnerability=18.8±5.2 J. Conclusions Our study highlights that Purkinje tissue can be ablated with IRE without any evidence of underlying myocardial damage.
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Affiliation(s)
- Christopher Livia
- Department of Cardiovascular Medicine and Department of Molecular Pharmacology and Experimental TherapeuticsCenter for Regenerative MedicineMayo ClinicRochesterMN
| | - Alan Sugrue
- Division of Heart Rhythm ServicesDepartment of Cardiovascular DiseasesMayo ClinicRochesterMN
| | - Tyra Witt
- Department of Cardiovascular Medicine and Department of Molecular Pharmacology and Experimental TherapeuticsCenter for Regenerative MedicineMayo ClinicRochesterMN
| | - Murray D. Polkinghorne
- Division of Heart Rhythm ServicesDepartment of Cardiovascular DiseasesMayo ClinicRochesterMN
| | - Elad Maor
- Leviev Heart Center, Sheba Medical CenterSackler School of MedicineTel Aviv UniversityTel AvivIsrael
| | - Suraj Kapa
- Division of Heart Rhythm ServicesDepartment of Cardiovascular DiseasesMayo ClinicRochesterMN
| | - Helge I. Lehmann
- Division of Heart Rhythm ServicesDepartment of Cardiovascular DiseasesMayo ClinicRochesterMN
| | - Christopher V. DeSimone
- Division of Heart Rhythm ServicesDepartment of Cardiovascular DiseasesMayo ClinicRochesterMN
| | - Atta Behfar
- Department of Cardiovascular Medicine and Department of Molecular Pharmacology and Experimental TherapeuticsCenter for Regenerative MedicineMayo ClinicRochesterMN
| | - Samuel J. Asirvatham
- Division of Heart Rhythm ServicesDepartment of Cardiovascular DiseasesMayo ClinicRochesterMN
- Division of Pediatric CardiologyDepartment of Pediatric and Adolescent MedicineMayo ClinicRochesterMN
| | - Christopher J. McLeod
- Division of Heart Rhythm ServicesDepartment of Cardiovascular DiseasesMayo ClinicRochesterMN
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24
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Tri J, Asirvatham R, DeSimone CV, Killu AM, Sugrue AM, Suddendorf SH, Ladewig DJ, Kapa S, Friedman PA, McLeod CJ, Asirvatham SJ. Intramural conduction system gradients and electrogram regularity during ventricular fibrillation. Indian Pacing Electrophysiol J 2018; 18:195-200. [PMID: 30036650 PMCID: PMC6303163 DOI: 10.1016/j.ipej.2018.07.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 06/06/2018] [Accepted: 07/19/2018] [Indexed: 11/25/2022] Open
Abstract
INTRODUCTION The His-Purkinje system has been shown to harbor triggers for ventricular fibrillation (VF) initiation. However, the substrate responsible for VF maintenance remains elusive. We hypothesized that standard, electrode-based, point-to-point mapping would yield meaningful insight into site-specific patterns and organization which may shed light on the critical substrate for maintenance of VF. METHODS VF was induced under general anesthesia by direct current (DC) application to the right ventricle in 7 acute canines. A standard EPT Blazer mapping catheter (Boston Scientific, Natuck, MA) was used for mapping in conjunction with a Prucka recording system. We collected 30 consecutive electrograms at 24 distinct sites, confirmed by fluoroscopy and intracardiac echo. These sites included both endocardial and epicardial locations throughout the ventricles and conduction system. RESULTS A total of 5040 individual data points were collected in 7 separate canine studies. During VF mapping, a transmural disparity was found between the epicardium (average cycle length [CL] of 1136 m s) and the endocardium (average CL of 123 m s) with a p value of <0.01. An additional, intramural gradient was found when comparing the proximal, insulated conduction system to the distal, non-insulated conduction system (average CL 218 versus 111 m s [p = 0.03]). CONCLUSION Our data are supportive of a novel observation of intramural difference between insulated and non-insulated regions of the His-Purkinje network in canines. In addition, certain areas exhibited periods of regular electrogram characteristics; this was despite the heart remaining in terminal VF. These early canine data merit further study to investigate if specific ablation of the distal conduction system can perturb or extinguish VF.
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Affiliation(s)
- Jason Tri
- Mayo Clinic Research Internship, Mayo Clinic, Rochester, MN, USA
| | | | | | - Ammar M Killu
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA
| | - Alan M Sugrue
- Division of Internal Medicine, Mayo Clinic, Rochester, MN, USA
| | | | | | - Suraj Kapa
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA
| | - Paul A Friedman
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA
| | | | - Samuel J Asirvatham
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA; Department of Pediatrics and Adolescent Medicine, Mayo Clinic, Rochester, MN, USA.
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25
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Martinez ME, Walton RD, Bayer JD, Haïssaguerre M, Vigmond EJ, Hocini M, Bernus O. Role of the Purkinje-Muscle Junction on the Ventricular Repolarization Heterogeneity in the Healthy and Ischemic Ovine Ventricular Myocardium. Front Physiol 2018; 9:718. [PMID: 29962961 PMCID: PMC6010581 DOI: 10.3389/fphys.2018.00718] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 05/24/2018] [Indexed: 01/23/2023] Open
Abstract
Alteration of action potential duration (APD) heterogeneity contributes to arrhythmogenesis. Purkinje-muscle junctions (PMJs) present differential electrophysiological properties including longer APD. The goal of this study was to determine if Purkinje-related or myocardial focal activation modulates ventricular repolarization differentially in healthy and ischemic myocardium. Simultaneous epicardial (EPI) and endocardial (ENDO) optical mapping was performed on sheep left ventricular (LV) wedges with intact free-running Purkinje network (N = 7). Preparations were paced on either ENDO or EPI surfaces, or the free-running Purkinje fibers (PFs), mimicking normal activation. EPI and ENDO APDs were assessed for each pacing configuration, before and after (7 min) of the onset of no-flow ischemia. Experiments were supported by simulations. In control conditions, maximal APD was found at endocardial PMJ sites. We observed a significant transmural APD gradient for PF pacing with PMJ APD = 347 ± 41 ms and EPI APD = 273 ± 36 ms (p < 0.001). A similar transmural gradient was observed when pacing ENDO (49 ± 31 ms; p = 0.005). However, the gradient was reduced when pacing EPI (37 ± 20 ms; p = 0.005). Global dispersion of repolarization was the most pronounced for EPI pacing. In ischemia, both ENDO and EPI APD were reduced (p = 0.005) and the transmural APD gradient (109 ± 55 ms) was increased when pacing ENDO compared to control condition or when pacing EPI (p < 0.05). APD maxima remained localized at functional PMJs during ischemia. Local repolarization dispersion was significantly higher at the PMJ than at other sites. The results were consistent with simulations. We found that the activation sequence modulates repolarization heterogeneity in the ischemic sheep LV. PMJs remain active following ischemia and exert significant influence on local repolarization patterns.
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Affiliation(s)
- Marine E Martinez
- Centre de Recherche Cardio-Thoracique de Bordeaux, Université de Bordeaux, Bordeaux, France.,INSERM U1045, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux, France.,IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France
| | - Richard D Walton
- Centre de Recherche Cardio-Thoracique de Bordeaux, Université de Bordeaux, Bordeaux, France.,INSERM U1045, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux, France.,IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France
| | - Jason D Bayer
- Centre de Recherche Cardio-Thoracique de Bordeaux, Université de Bordeaux, Bordeaux, France.,UMR5251, Centre National De La Recherche Scientifique, Institut de Mathématiques de Bordeaux, Bordeaux, France
| | - Michel Haïssaguerre
- Centre de Recherche Cardio-Thoracique de Bordeaux, Université de Bordeaux, Bordeaux, France.,INSERM U1045, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux, France.,IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France.,Centre Hospitalier Universitaire, Bordeaux University Hospital, Hopital Cardiologique du Haut Lévèque, Bordeaux, France
| | - Edward J Vigmond
- Centre de Recherche Cardio-Thoracique de Bordeaux, Université de Bordeaux, Bordeaux, France.,UMR5251, Centre National De La Recherche Scientifique, Institut de Mathématiques de Bordeaux, Bordeaux, France
| | - Mélèze Hocini
- Centre de Recherche Cardio-Thoracique de Bordeaux, Université de Bordeaux, Bordeaux, France.,INSERM U1045, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux, France.,IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France.,Centre Hospitalier Universitaire, Bordeaux University Hospital, Hopital Cardiologique du Haut Lévèque, Bordeaux, France
| | - Olivier Bernus
- Centre de Recherche Cardio-Thoracique de Bordeaux, Université de Bordeaux, Bordeaux, France.,INSERM U1045, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux, France.,IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France
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26
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Panitchob N, Li L, Huang J, Ranjan R, Ideker RE, Dosdall DJ. Endocardial Activation Drives Activation Patterns During Long-Duration Ventricular Fibrillation and Defibrillation. Circ Arrhythm Electrophysiol 2017; 10:CIRCEP.117.005562. [PMID: 29247031 DOI: 10.1161/circep.117.005562] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 10/26/2017] [Indexed: 11/16/2022]
Abstract
BACKGROUND Understanding the mechanisms that drive ventricular fibrillation is essential for developing improved defibrillation techniques to terminate ventricular fibrillation (VF). Distinct organization patterns of chaotic, regular, and synchronized activity were previously demonstrated in VF that persisted over 1 to 2 minutes (long-duration VF [LDVF]). We hypothesized that activity on the endocardium may be driving these activation patterns in LDVF and that unsuccessful defibrillation shocks may alter activation patterns. METHODS AND RESULTS The study was performed using a 64-electrode basket catheter on the left ventricle endocardium and 54 6-electrode plunge needles inserted into the left ventricles of 6 dogs. VF was induced electrically, and after short-duration VF (10 seconds) and LDVF (7 minutes), shocks of increasing strengths were delivered every 10 seconds until VF was terminated. Endocardial activation patterns were classified as chaotic (varying cycle lengths and nonsynchronous activations), regular (highly repeatable cycle lengths), and synchronized (activation that spreads rapidly over the endocardium with diastolic periods between activations). CONCLUSIONS The results showed that the chaotic pattern was predominant in early VF, but the regular pattern emerges as VF progressed. The synchronized pattern only emerged occasionally during late VF. Failed defibrillation shocks changed chaotic and regular activation patterns to synchronized patterns in LDVF but not in short-duration VF. The regular and synchronized patterns of activation were driven by rapid activations on the endocardial surface that blocked and broke up transmurally, leading to an endocardial to epicardial activation rate gradient as LDVF progressed.
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Affiliation(s)
- Nuttanont Panitchob
- From the Nora Eccles Harrison Cardiovascular Research and Training Institute (N.P., R.R., D.J.D.), Division of Cardiothoracic Surgery, Department of Surgery (D.J.D.), and Division of Cardiovascular Medicine, Department of Medicine (L.L., R.R., D.J.D.), University of Utah, Salt Lake City; and Division of Cardiovascular Disease, School of Medicine, University of Alabama at Birmingham (J.H., R.E.I.)
| | - Li Li
- From the Nora Eccles Harrison Cardiovascular Research and Training Institute (N.P., R.R., D.J.D.), Division of Cardiothoracic Surgery, Department of Surgery (D.J.D.), and Division of Cardiovascular Medicine, Department of Medicine (L.L., R.R., D.J.D.), University of Utah, Salt Lake City; and Division of Cardiovascular Disease, School of Medicine, University of Alabama at Birmingham (J.H., R.E.I.)
| | - Jian Huang
- From the Nora Eccles Harrison Cardiovascular Research and Training Institute (N.P., R.R., D.J.D.), Division of Cardiothoracic Surgery, Department of Surgery (D.J.D.), and Division of Cardiovascular Medicine, Department of Medicine (L.L., R.R., D.J.D.), University of Utah, Salt Lake City; and Division of Cardiovascular Disease, School of Medicine, University of Alabama at Birmingham (J.H., R.E.I.)
| | - Ravi Ranjan
- From the Nora Eccles Harrison Cardiovascular Research and Training Institute (N.P., R.R., D.J.D.), Division of Cardiothoracic Surgery, Department of Surgery (D.J.D.), and Division of Cardiovascular Medicine, Department of Medicine (L.L., R.R., D.J.D.), University of Utah, Salt Lake City; and Division of Cardiovascular Disease, School of Medicine, University of Alabama at Birmingham (J.H., R.E.I.)
| | - Raymond E Ideker
- From the Nora Eccles Harrison Cardiovascular Research and Training Institute (N.P., R.R., D.J.D.), Division of Cardiothoracic Surgery, Department of Surgery (D.J.D.), and Division of Cardiovascular Medicine, Department of Medicine (L.L., R.R., D.J.D.), University of Utah, Salt Lake City; and Division of Cardiovascular Disease, School of Medicine, University of Alabama at Birmingham (J.H., R.E.I.)
| | - Derek J Dosdall
- From the Nora Eccles Harrison Cardiovascular Research and Training Institute (N.P., R.R., D.J.D.), Division of Cardiothoracic Surgery, Department of Surgery (D.J.D.), and Division of Cardiovascular Medicine, Department of Medicine (L.L., R.R., D.J.D.), University of Utah, Salt Lake City; and Division of Cardiovascular Disease, School of Medicine, University of Alabama at Birmingham (J.H., R.E.I.).
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27
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Restitution characteristics of His bundle and working myocardium in isolated rabbit hearts. PLoS One 2017; 12:e0186880. [PMID: 29073179 PMCID: PMC5658095 DOI: 10.1371/journal.pone.0186880] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 10/09/2017] [Indexed: 12/16/2022] Open
Abstract
The Purkinje system (PS) and the His bundle have been recently implicated as an important driver of the rapid activation rate after 1-2 minutes of ventricular fibrillation (VF). It is unknown whether activations during VF propagate through the His-Purkinje system to other portions of the the working myocardium (WM). Little is known about restitution characteristic differences between the His bundle and working myocardium at short cycle lengths. In this study, rabbit hearts (n = 9) were isolated, Langendorff-perfused, and electromechanically uncoupled with blebbistatin (10 μM). Pacing pulses were delivered directly to the His bundle. By using standard glass microelectrodes, action potentials duration (APD) from the His bundle and WM were obtained simultaneously over a wide range of stimulation cycle lengths (CL). The global F-test indicated that the two restitution curves of the His bundle and the WM are statistically significantly different (P<0.05). Also, the APD of the His bundle was significantly shorter than that of WM throughout the whole pacing course (P<0.001). The CL at which alternans developed in the His bundle vs. the WM were shorter for the His bundle (134.2±13.1ms vs. 148.3±13.3ms, P<0.01) and 2:1 block developed at a shorter CL in the His bundle than in WM (130.0±10.0 vs. 145.6±14.2ms, P<0.01). The His bundle APD was significantly shorter than that of WM under both slow and rapid pacing rates, which suggest that there may be an excitable gap during VF and that the His bundle may conduct wavefronts from one bundle branch to the other at short cycle lengths and during VF.
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29
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Nayak AR, Panfilov AV, Pandit R. Spiral-wave dynamics in a mathematical model of human ventricular tissue with myocytes and Purkinje fibers. Phys Rev E 2017; 95:022405. [PMID: 28297843 DOI: 10.1103/physreve.95.022405] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Indexed: 06/06/2023]
Abstract
We present systematic numerical studies of the possible effects of the coupling of human endocardial and Purkinje cells at cellular and two-dimensional tissue levels. We find that the autorhythmic-activity frequency of the Purkinje cell in a composite decreases with an increase in the coupling strength; this can even eliminate the autorhythmicity. We observe a delay between the beginning of the action potentials of endocardial and Purkinje cells in a composite; such a delay increases as we decrease the diffusive coupling, and eventually a failure of transmission occurs. An increase in the diffusive coupling decreases the slope of the action-potential-duration-restitution curve of an endocardial cell in a composite. By using a minimal model for the Purkinje network, in which we have a two-dimensional, bilayer tissue, with a layer of Purkinje cells on top of a layer of endocardial cells, we can stabilize spiral-wave turbulence; however, for a sparse distribution of Purkinje-ventricular junctions, at which these two layers are coupled, we can also obtain additional focal activity and many complex transient regimes. We also present additional effects resulting from the coupling of Purkinje and endocardial layers and discuss the relation of our results to the studies performed in anatomically accurate models of the Purkinje network.
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Affiliation(s)
- Alok Ranjan Nayak
- International Institute of Information Technology (IIIT-Bhubaneswar), Gothapatna, Po: Malipada, Bhubaneswar 751003, India
| | - A V Panfilov
- Department of Physics and Astronomy, Gent University, Krijgslaan 281, S9, 9000 Gent, Belgium
- Moscow Institute of Physics and Technology (State University), Dolgoprudny, Moscow Region, Russia
| | - Rahul Pandit
- Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India
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30
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31
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Hoffman MJ, LaVigne NS, Scorse ST, Fenton FH, Cherry EM. Reconstructing three-dimensional reentrant cardiac electrical wave dynamics using data assimilation. CHAOS (WOODBURY, N.Y.) 2016; 26:013107. [PMID: 26826859 DOI: 10.1063/1.4940238] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
For many years, reentrant scroll waves have been predicted and studied as an underlying mechanism for cardiac arrhythmias using numerical techniques, and high-resolution mapping studies using fluorescence recordings from the surfaces of cardiac tissue preparations have confirmed the presence of visible spiral waves. However, assessing the three-dimensional dynamics of these reentrant waves using experimental techniques has been limited to verifying stable scroll-wave dynamics in relatively thin preparations. We propose a different approach to recovering the three-dimensional dynamics of reentrant waves in the heart. By applying techniques commonly used in weather forecasting, we combine dual-surface observations from a particular experiment with predictions from a numerical model to reconstruct the full three-dimensional time series of the experiment. Here, we use model-generated surrogate observations from a numerical experiment to evaluate the performance of the ensemble Kalman filter in reconstructing such time series for a discordant alternans state in one spatial dimension and for scroll waves in three dimensions. We show that our approach is able to recover time series of both observed and unobserved variables matching the truth. Where nearby observations are available, the error is reduced below the synthetic observation error, with a smaller reduction with increased distance from observations. Our findings demonstrate that state reconstruction for spatiotemporally complex cardiac electrical dynamics is possible and will lead naturally to applications using real experimental data.
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Affiliation(s)
- M J Hoffman
- School of Mathematical Sciences, Rochester Institute of Technology, Rochester, New York 14623, USA
| | - N S LaVigne
- Department of Mathematics, SUNY Geneseo, Geneseo, New York 14454, USA
| | - S T Scorse
- School of Mathematical Sciences, Rochester Institute of Technology, Rochester, New York 14623, USA
| | - F H Fenton
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - E M Cherry
- School of Mathematical Sciences, Rochester Institute of Technology, Rochester, New York 14623, USA
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32
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Image-Based Structural Modeling of the Cardiac Purkinje Network. BIOMED RESEARCH INTERNATIONAL 2015; 2015:621034. [PMID: 26583120 PMCID: PMC4637159 DOI: 10.1155/2015/621034] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 03/28/2015] [Indexed: 11/18/2022]
Abstract
The Purkinje network is a specialized conduction system within the heart that ensures the proper activation of the ventricles to produce effective contraction. Its role during ventricular arrhythmias is less clear, but some experimental studies have suggested that the Purkinje network may significantly affect the genesis and maintenance of ventricular arrhythmias. Despite its importance, few structural models of the Purkinje network have been developed, primarily because current physical limitations prevent examination of the intact Purkinje network. In previous modeling efforts Purkinje-like structures have been developed through either automated or hand-drawn procedures, but these networks have been created according to general principles rather than based on real networks. To allow for greater realism in Purkinje structural models, we present a method for creating three-dimensional Purkinje networks based directly on imaging data. Our approach uses Purkinje network structures extracted from photographs of dissected ventricles and projects these flat networks onto realistic endocardial surfaces. Using this method, we create models for the combined ventricle-Purkinje system that can fully activate the ventricles through a stimulus delivered to the Purkinje network and can produce simulated activation sequences that match experimental observations. The combined models have the potential to help elucidate Purkinje network contributions during ventricular arrhythmias.
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33
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Mechanisms of Long-Duration Ventricular Fibrillation in Human Hearts and Experimental Validation in Canine Purkinje Fibers. JACC Clin Electrophysiol 2015; 1:187-197. [DOI: 10.1016/j.jacep.2015.04.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 04/03/2015] [Accepted: 04/09/2015] [Indexed: 11/20/2022]
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Kay M, Kuzmiak-Glancy S, Rogers J. Racing to the flatline: heart rate and β-adrenergic stimulation quicken the pace. Am J Physiol Heart Circ Physiol 2015; 308:H977-9. [DOI: 10.1152/ajpheart.00154.2015] [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: 11/22/2022]
Affiliation(s)
- Matthew Kay
- Department of Biomedical Engineering, The George Washington University, Washington, District of Columbia; and
| | - Sarah Kuzmiak-Glancy
- Department of Biomedical Engineering, The George Washington University, Washington, District of Columbia; and
| | - Jack Rogers
- Department of Biomedical Engineering, The University of Alabama at Birmingham, Department of Biomedical Engineering, Birmingham, Alabama
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35
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Hooks DA, Berte B, Yamashita S, Mahida S, Sellal JM, Aljefairi N, Frontera A, Derval N, Denis A, Hocini M, Haïssaguerre M, Jaïs P, Sacher F. New strategies for ventricular tachycardia and ventricular fibrillation ablation. Expert Rev Cardiovasc Ther 2015; 13:263-76. [DOI: 10.1586/14779072.2015.1009039] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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36
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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: 33] [Impact Index Per Article: 3.3] [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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Lin C, Jin Q, Zhang N, Zhou J, Pang Y, Xin Y, Liu S, Wu Q, Wu L. Endocardial focal activation originating from Purkinje fibers plays a role in the maintenance of long duration ventricular fibrillation. Croat Med J 2014; 55:121-7. [PMID: 24778098 PMCID: PMC4009712 DOI: 10.3325/cmj.2014.55.121] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Aim To determine the role of repetitive endocardial focal activations and Purkinje fibers in the maintenance of long duration ventricular fibrillation (LDVF, VF>1 minute) in canine hearts in vivo. Methods The study was conducted in electrophysiological laboratory of Shanghai Ruijin hospital from July 2010 to August 2012. A 64-electrode basket was introduced through a carotid artery into the left ventricle (LV) of 11 beagle dogs for global endocardial electrical mapping. In the Lugol’s solution group (n = 5), the subendocardium was ablated by washing with Lugol’s solution. In the control group, (n = 6) saline was used for ablation. Before and after saline or Lugol ablation, we determined QRS duration and QT/QTc interval in sinus rhythm (SR). We also measured the activation rates in the first 2 seconds of each minute during 7 minutes of VF for each group. If VF terminated spontaneously in less than 7 minutes, the VF segments used in activation rate analysis were reduced accordingly. Results At the beginning of VF there was no difference between the groups in the activation rate. However, after 1 minute of LDVF the Lugol’s solution group had significantly slower activation rate than the control group. In the control group, all episodes of LDVF (6/6) were successfully sustained for 7 minutes, while in the Lugol’s solution group 4/5 episodes of LDVF spontaneously terminated before 7 minutes (4.8 ± 1.4 minutes) (P = 0.015). In the control group, at 5.1 ± 1.3 minutes of LDVF, a successive, highly organized focal LV endocardial activation pattern was observed. During this period, activations partly arose in PF and spread to the working ventricular myocardium. Mapping analysis showed that these events were consistent with repetitive endocardial focal activations. No evidence of similar focal activations was observed in the Lugol’s solution group. Conclusions Repetitive endocardial focal activations in the LV endocardium may be associated with activation of subendocardial PFs. This mechanism may play an important role in the maintenance of LDVF.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Liqun Wu
- Liqun Wu, Department of Cardiology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, No.197, Shanghai Rui Jin Er Road, Shanghai, P.R. China, 200025,
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Angel N, Li L, Dosdall DJ. His bundle activates faster than ventricular myocardium during prolonged ventricular fibrillation. PLoS One 2014; 9:e101666. [PMID: 25036418 PMCID: PMC4103805 DOI: 10.1371/journal.pone.0101666] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 06/09/2014] [Indexed: 11/30/2022] Open
Abstract
Background The Purkinje fiber system has recently been implicated as an important driver of the rapid activation rate during long duration ventricular fibrillation (VF>2 minutes). The goal of this study is to determine whether this activity propagates to or occurs in the proximal specialized conduction system during VF as well. Methods and Results An 8×8 array with 300 µm spaced electrodes was placed over the His bundles of isolated, perfused rabbit hearts (n = 12). Ventricular myocardial (VM) and His activations were differentiated by calculating Laplacian recordings from unipolar signals. Activation rates of the VM and His bundle were compared and the His bundle conduction velocity was measured during perfused VF followed by 8 minutes of unperfused VF. During perfused VF the average VM activation rate of 11.04 activations/sec was significantly higher than the His bundle activation rate of 6.88 activations/sec (p<0.05). However from 3–8 minutes of unperfused VF the His system activation rate (6.16, 5.53, 5.14, 5.22, 6.00, and 4.62 activations/sec significantly faster than the rate of the VM (4.67, 3.63, 2.94, 2.24, 3.45, and 2.31 activations/sec) (p<0.05). The conduction velocity of the His system immediately decreased to 94% of the sinus rate during perfused VF then gradually decreased to 67% of sinus rhythm conduction at 8 minutes of unperfused VF. Conclusion During prolonged VF the activation rate of the His bundle is faster than that of the VM. This suggests that the proximal conduction system, like the distal Purkinje system, may be an important driver during long duration VF and may be a target for interventional therapy.
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Affiliation(s)
- Nathan Angel
- Comprehensive Arrhythmia Research & Management Center, Division of Cardiovascular Medicine, University of Utah, Salt Lake City, UT, United States of America
- Department of Bioengineering, University of Utah, Salt Lake City, UT, United States of America
| | - Li Li
- Comprehensive Arrhythmia Research & Management Center, Division of Cardiovascular Medicine, University of Utah, Salt Lake City, UT, United States of America
| | - Derek J. Dosdall
- Comprehensive Arrhythmia Research & Management Center, Division of Cardiovascular Medicine, University of Utah, Salt Lake City, UT, United States of America
- Department of Bioengineering, University of Utah, Salt Lake City, UT, United States of America
- Center for Engineering Innovation, University of Utah, Salt Lake City, UT, United States of America
- * E-mail:
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Pravdin SF, Dierckx H, Katsnelson LB, Solovyova O, Markhasin VS, Panfilov AV. Electrical wave propagation in an anisotropic model of the left ventricle based on analytical description of cardiac architecture. PLoS One 2014; 9:e93617. [PMID: 24817308 PMCID: PMC4015904 DOI: 10.1371/journal.pone.0093617] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Accepted: 02/27/2014] [Indexed: 11/19/2022] Open
Abstract
We develop a numerical approach based on our recent analytical model of fiber structure in the left ventricle of the human heart. A special curvilinear coordinate system is proposed to analytically include realistic ventricular shape and myofiber directions. With this anatomical model, electrophysiological simulations can be performed on a rectangular coordinate grid. We apply our method to study the effect of fiber rotation and electrical anisotropy of cardiac tissue (i.e., the ratio of the conductivity coefficients along and across the myocardial fibers) on wave propagation using the ten Tusscher–Panfilov (2006) ionic model for human ventricular cells. We show that fiber rotation increases the speed of cardiac activation and attenuates the effects of anisotropy. Our results show that the fiber rotation in the heart is an important factor underlying cardiac excitation. We also study scroll wave dynamics in our model and show the drift of a scroll wave filament whose velocity depends non-monotonically on the fiber rotation angle; the period of scroll wave rotation decreases with an increase of the fiber rotation angle; an increase in anisotropy may cause the breakup of a scroll wave, similar to the mother rotor mechanism of ventricular fibrillation.
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Affiliation(s)
- Sergey F. Pravdin
- Function Approximation Theory Department, Institute of Mathematics and Mechanics, Ekaterinburg, Russia
- Laboratory of Mathematical Physiology, Institute of Immunology and Physiology, Ekaterinburg, Russia
- Department of Physics and Astronomy, Faculty of Sciences, Ghent University, Ghent, Belgium
- * E-mail: (SFP); (AVP)
| | - Hans Dierckx
- Department of Physics and Astronomy, Faculty of Sciences, Ghent University, Ghent, Belgium
| | - Leonid B. Katsnelson
- Laboratory of Mathematical Physiology, Institute of Immunology and Physiology, Ekaterinburg, Russia
- Ural Federal University, Ekaterinburg, Russia
| | - Olga Solovyova
- Laboratory of Mathematical Physiology, Institute of Immunology and Physiology, Ekaterinburg, Russia
- Ural Federal University, Ekaterinburg, Russia
| | - Vladimir S. Markhasin
- Laboratory of Mathematical Physiology, Institute of Immunology and Physiology, Ekaterinburg, Russia
- Ural Federal University, Ekaterinburg, Russia
| | - Alexander V. Panfilov
- Department of Physics and Astronomy, Faculty of Sciences, Ghent University, Ghent, Belgium
- Moscow Institute of Physics and Technology (State University), Dolgoprudny, Moscow Region, Russia
- * E-mail: (SFP); (AVP)
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Willems S, Hoffmann BA, Schaeffer B, Sultan A, Schreiber D, Lüker J, Steven D. Mapping and ablation of ventricular fibrillation—how and for whom? J Interv Card Electrophysiol 2014; 40:229-35. [DOI: 10.1007/s10840-014-9886-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Accepted: 02/11/2014] [Indexed: 11/29/2022]
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Huang J, Dosdall DJ, Cheng KA, Li L, Rogers JM, Ideker RE. The importance of Purkinje activation in long duration ventricular fibrillation. J Am Heart Assoc 2014; 3:e000495. [PMID: 24584738 PMCID: PMC3959715 DOI: 10.1161/jaha.113.000495] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND The mechanisms that maintain long duration ventricular fibrillation (LDVF) are unclear. The difference in distribution of the Purkinje system in dogs and pigs was explored to determine if Purkinje activation propagates to stimulate working myocardium (WM) during LDVF and WM pacing. METHODS AND RESULTS In-vivo extracellular recordings were made from 1044 intramural plunge and epicardial plaque electrodes in 6 pig and 6 dog hearts. Sinus activation propagated sequentially from the endocardium to the epicardium in dogs but not pigs. During epicardial pacing, activation propagated along the endocardium and traversed the LV wall almost parallel to the epicardium in dogs, but in pigs propagated away from the pacing site approximately perpendicular to the epicardium. After 1 minute of VF, activation rate near the endocardium was significantly faster than near the epicardium in dogs (P<0.01) but not pigs (P>0.05). From 2 to 10 minutes of LDVF, recordings exhibiting Purkinje activations were near the endocardium in dogs (P<0.01) but were scattered transmurally in pigs, and the WM activation rate in recordings in which Purkinje activations were present was significantly faster than the WM activation rate in recordings in which Purkinje activations were absent (P<0.01). In 10 isolated perfused dog hearts, the LV endocardium was exposed and 2 microelectrodes were inserted into Purkinje and adjacent myocardial cells. After 5 minutes of LDVF, mean Purkinje activation rate was significantly faster than mean WM activation rate (P<0.01). CONCLUSION These extracellular and intracellular findings about activation support the hypothesis that Purkinje activation propagates to stimulate WM during sinus rhythm, pacing, and LDVF.
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Affiliation(s)
- Jian Huang
- Cardiac Rhythm Management Laboratory, Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, AL
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The role of Purkinje-myocardial coupling during ventricular arrhythmia: a modeling study. PLoS One 2014; 9:e88000. [PMID: 24516576 PMCID: PMC3917859 DOI: 10.1371/journal.pone.0088000] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 01/03/2014] [Indexed: 11/21/2022] Open
Abstract
The Purkinje system is the fast conduction network of the heart which couples to the myocardium at discrete sites called Purkinje-Myocyte Junctions (PMJs). However, the distribution and number of PMJs remains elusive, as does whether a particular PMJ is functional. We hypothesized that the Purkinje system plays a role during reentry and that the number of functional PMJs affect reentry dynamics. We used a computer finite element model of rabbit ventricles in which we varied the number of PMJs. Sustained, complex reentry was induced by applying an electric shock and the role of the Purkinje system in maintaining the arrhythmia was assessed by analyzing phase singularities, frequency of activation, and bidirectional propagation at PMJs. For larger junctional resistances, increasing PMJ density increased the mean firing rate in the Purkinje system, the percentage of successful retrograde conduction at PMJs, and the incidence of wave break on the epicardium. However, the mean firing of the ventricles was not affected. Furthermore, increasing PMJ density above 13/ did not alter reentry dynamics. For lower junctional resistances, the trend was not as clear. We conclude that Purkinje system topology affects reentry dynamics and conditions which alter PMJ density can alter reentry dynamics.
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Affiliation(s)
- Dan M Roden
- Vanderbilt University School of Medicine, Nashville, TN
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Boyle PM, Massé S, Nanthakumar K, Vigmond EJ. Transmural IK(ATP) heterogeneity as a determinant of activation rate gradient during early ventricular fibrillation: mechanistic insights from rabbit ventricular models. Heart Rhythm 2013; 10:1710-7. [PMID: 23948344 DOI: 10.1016/j.hrthm.2013.08.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Indexed: 10/26/2022]
Abstract
BACKGROUND Activation rate (AR) gradients develop during ventricular fibrillation (VF), with the highest AR on the surface near Purkinje system (PS) terminals (endocardium in humans and rabbits and epicardium in pigs). The application of glibenclamide to block adenosine triphosphate (ATP)-sensitive potassium current (IK(ATP)) before VF induction eliminates transmural AR gradients and prevents the induction of sustained arrhythmia. It remains unclear whether the PS, which is resistant to ischemia, is also a factor in AR heterogeneity. OBJECTIVE To dissect IK(ATP) and PS contributions to AR gradients during VF by using detailed computer simulations. METHODS We constructed rabbit ventricular models with either subendocardial or subepicardial PS terminals. Physiologically relevant IK(ATP) gradients were implemented, and early VF was induced and observed. RESULTS Prominent AR gradients were observed only in models with large IK(ATP) gradients. The critical underlying factor of AR gradient maintenance was refractoriness in low-IK(ATP) regions, which blocked the propagation of action potentials from high-IK(ATP) regions. The PS played no role in transmural AR gradient maintenance, but did cause local spatial heterogeneity of AR on the surface adjacent to terminals. Simulated glibenclamide application during VF led to spontaneous arrhythmia termination within a few seconds in most cases, which builds on previous experimental findings of anti-VF properties of glibenclamide pretreatment. CONCLUSION Differential IK(ATP) across the ventricular wall is an important factor underlying AR gradients during VF; thus, higher epicardial AR in pigs is most likely due to an abundance of epicardial IK(ATP). For terminating early VF, our results suggest that IK(ATP) modulation is a stronger target than Purkinje ablation.
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Affiliation(s)
- Patrick M Boyle
- University of Calgary, Calgary, Alberta, Canada; Institute for Computational Medicine, Johns Hopkins University, Baltimore, Maryland.
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Taylor TG, Venable PW, Booth A, Garg V, Shibayama J, Zaitsev AV. Does the combination of hyperkalemia and KATP activation determine excitation rate gradient and electrical failure in the globally ischemic fibrillating heart? Am J Physiol Heart Circ Physiol 2013; 305:H903-12. [PMID: 23873793 DOI: 10.1152/ajpheart.00184.2013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ventricular fibrillation (VF) in the globally ischemic heart is characterized by a progressive electrical depression manifested as a decline in the VF excitation rate (VFR) and loss of excitability, which occur first in the subepicardium (Epi) and spread to the subendocardium (Endo). Early electrical failure is detrimental to successful defibrillation and resuscitation during cardiac arrest. Hyperkalemia and/or the activation of ATP-sensitive K(+) (KATP) channels have been implicated in electrical failure, but the role of these factors in ischemic VF is poorly understood. We determined the VFR-extracellular K(+) concentration ([K(+)]o) relationship in the Endo and Epi of the left ventricle during VF in globally ischemic hearts (Isch group) and normoxic hearts subjected to hyperkalemia (HighK group) or a combination of hyperkalemia and the KATP channel opener cromakalim (HighK-Crom group). In the Isch group, Endo and Epi values of [K(+)]o and VFR were compared in the early (0-6 min), middle (7-13 min), and late (14-20 min) phases of ischemic VF. A significant transmural gradient in VFR (Endo > Epi) was observed in all three phases, whereas a significant transmural gradient in [K(+)]o (Epi > Endo) occurred only in the late phase of ischemic VF. In the Isch group, the VFR decrease and inexcitability started to occur at much lower [K(+)]o than in the HighK group, especially in the Epi. Combining KATP activation with hyperkalemia only shifted the VFR-[K(+)]o curve upward (an effect opposite to real ischemia) without changing the [K(+)]o threshold for asystole. We conclude that hyperkalemia and/or KATP activation cannot adequately explain the heterogeneous electrical depression and electrical failure during ischemic VF.
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Affiliation(s)
- Tyson G Taylor
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah
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Nayyar S, Ganesan AN, Brooks AG, Sullivan T, Roberts-Thomson KC, Sanders P. Venturing into ventricular arrhythmia storm: a systematic review and meta-analysis. Eur Heart J 2012; 34:560-71. [DOI: 10.1093/eurheartj/ehs453] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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Li L, Zheng X, Dosdall DJ, Huang J, Ideker RE. Different types of long-duration ventricular fibrillation: can they be identified by electrocardiography. J Electrocardiol 2012; 45:658-9. [PMID: 23022307 DOI: 10.1016/j.jelectrocard.2012.08.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Indexed: 11/19/2022]
Abstract
We tested the hypothesis that after 2 minutes of ventricular fibrillation (VF), periods of highly organized activations occur on the endocardium, arising from an intramural mother rotor or triggered activity originating in the Purkinje fibers. In 6 anesthetized dogs, we recorded electrically induced VF from two-thirds of the endocardium with a 64-electrode basket catheter. In another 12 dogs, the study was repeated with the addition of the early afterdepolarization blocker pinacidil in 6 animals and the delayed afterdepolarization blocker flunarizine in the other 6 animals. We found that, in addition to periods of disorganized chaotic activation (type I pattern), at between 3 and 7 minutes of VF, 2 highly organized patterns were observed (type II pattern, regular activity and type III pattern, triggered activity). When present, these patterns were observed in all 64 electrodes simultaneously. Type II arises from the apex and may be an intramural mother rotor and type III arises focally in Purkinje fibers and may be caused by early afterdepolarizations. The optimal defibrillation strategy may be different for the 3 different VF patterns. Therefore, it is important to determine if these 3 patterns can be differentiated from the body surface electrocardiogram.
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Affiliation(s)
- Li Li
- CARMA Center, Division of Cardiology, University of Utah School of Medicine, Salt Lake City, UT 35294-0019, USA
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Taylor TG, Venable PW, Shibayama J, Warren M, Zaitsev AV. Role of KATP channel in electrical depression and asystole during long-duration ventricular fibrillation in ex vivo canine heart. Am J Physiol Heart Circ Physiol 2012; 302:H2396-409. [PMID: 22467302 PMCID: PMC3378304 DOI: 10.1152/ajpheart.00752.2011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Accepted: 03/22/2012] [Indexed: 11/22/2022]
Abstract
Long-duration ventricular fibrillation (LDVF) in the globally ischemic heart is characterized by transmurally heterogeneous decline in ventricular fibrillation rate (VFR), emergence of inexcitable regions, and eventual global asystole. Rapid loss of both local and global excitability is detrimental to successful defibrillation and resuscitation during cardiac arrest. We sought to assess the role of the ATP-sensitive potassium current (I(KATP)) in the timing and spatial pattern of electrical depression during LDVF in a structurally normal canine heart. We analyzed endo-, mid-, and epicardial unipolar electrograms and epicardial optical recordings in the left ventricle of isolated canine hearts during 10 min of LDVF in the absence (control) and presence of an I(KATP) blocker glybenclamide (60 μM). In all myocardial layers, average VFR was the same or higher in glybenclamide-treated than in control hearts. The difference increased with time of LDVF and was overall significant in all layers (P < 0.05). However, glybenclamide did not significantly affect the transmural VFR gradient. In epicardial optical recordings, glybenclamide shortened diastolic intervals, prolonged action potential duration, and decreased the percentage of inexcitable area (all differences P < 0.001). During 10 min of LDVF, asystole occurred in 55.6% of control and none of glybenclamide-treated hearts (P < 0.05). In three hearts paced after the onset of asystole, there was no response to LV epicardial or atrial pacing. In structurally normal canine hearts, I(KATP) opening during LDVF is a major factor in the onset of local and global inexcitability, whereas it has a limited role in overall deceleration of VFR and the transmural VFR gradient.
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Affiliation(s)
- Tyson G Taylor
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, 84112-5000, USA
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Tan VH, Yap J, Hsu, LF, Liew R. Catheter ablation of ventricular fibrillation triggers and electrical storm. Europace 2012; 14:1687-95. [DOI: 10.1093/europace/eus050] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Johnson CM, Pogwizd SM. Focal initiation of sustained and nonsustained ventricular tachycardia in a canine model of ischemic cardiomyopathy. J Cardiovasc Electrophysiol 2011; 23:543-52. [PMID: 22175759 DOI: 10.1111/j.1540-8167.2011.02239.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
INTRODUCTION To define the role of focal and reentrant mechanisms underlying nonsustained (NSVT) and sustained ventricular tachycardia (SuVT) induced by programmed stimulation, 3-dimensional cardiac mapping was performed in 8 dogs with heart failure (HF) created by multiple intracoronary microsphere embolizations. METHODS AND RESULTS Continuous recording from 232 intramural sites throughout the left and right ventricles and the interventricular septum was performed during programmed stimulation in the absence and presence of isoproterenol (Iso, 0.1 μg/kg/min). Sinus beats and the last extrastimuli preceding induced VT conducted with total activation times (TA) of 51 ± 10 and 111 ± 8 milliseconds, respectively, that did not change during Iso infusion (47 ± 4 and 109 ± 5 milliseconds, P = NS). NSVT was induced in 75% of HF dogs; SuVT was induced in 38%. In all cases, initiation and maintenance of SuVT and NSVT arose by a focal mechanism. Compared to NSVT, SuVT had a shorter coupling interval (CI; 150 ± 7 vs 186 ± 16, P < 0.05) and a predilection for certain critical subendocardial initiation sites (that were initiation sites for only 29% of NSVT beats). After 21-30 beats, acceleration of SuVT by a focal mechanism to a CI less than 120 milliseconds led to functional conduction delay (TA increasing from 111 ± 3 to 137 ± 3 milliseconds, P < 0.0001), intramural reentry, and transition to ventricular fibrillation. CONCLUSIONS Thus, initiation of SuVT in a model of ischemic HF is due to a focal mechanism. However, subsequent acceleration of this focal mechanism can ultimately lead to functional conduction delay and development of intramural reentry.
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Affiliation(s)
- Carolyn M Johnson
- Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
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