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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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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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Xing C, Jin Q, Zhang N, Liu S, Lin C, Wu Q, Luo Q, Liu A, Wu L. Effect of flunarizine on defibrillation outcomes and early refibrillation in a canine model of prolonged ventricular fibrillation. Exp Physiol 2019; 104:1630-1637. [PMID: 31465138 PMCID: PMC6899960 DOI: 10.1113/ep087068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 08/23/2019] [Indexed: 11/20/2022]
Abstract
New Findings What is the central question of this study? Can successful electrical shock in combination with a delayed after‐depolarization (DAD) blocker suppress early refibrillation episodes following long duration ventricular fibrillation (LDVF)? What is the main finding and its importance? Flunarizine significantly reduced the activation of LDVF and early ventricular fibrillation (VF) recurrence following LDVF, suggesting that DADs potentially contribute to refibrillation in prolonged VF. Thus, DAD inhibition can be used as an adjunctive therapy for electrical defibrillation to treat prolonged VF and suppress refibrillation following LDVF.
Abstract This study attempts to detect changes in the defibrillation threshold (DFT) at different stages of ventricular fibrillation (VF) (short duration VF, SDVF; long duration VF, LDVF) and during early refibrillation following successful defibrillation of LDVF by giving flunarizine, a blocker of delayed after‐depolarizations (DADs). Twelve beagles were divided into two groups (the control group, n = 6; and the flunarizine group, n = 6). Two 64‐electrode basket catheters were deployed into the left and the right ventricles for global endocardium mapping. The DFTs of SDVF and LDVF were determined at 20 s and 7 min, respectively, after VF induction in each group. Any refibrillation episodes were recorded within 15 min after the first successful defibrillation of LDVF. In the flunarizine group, the SDVF‐DFT values before and after the drug were not significantly different. The 7 min LDVF‐DFTs were markedly reduced by 26% (P < 0.05, the control group) and 38% (P < 0.01, the flunarizine group) compared to the 20 s SDVF‐DFTs within each group. The difference between SDVF‐DFT and LDVF‐DFT after flunarizine was larger than that in the control group (213 ± 65 vs. 120 ± 84 V, P < 0.05). The number of refibrillation episodes per animal (1.3 ± 1.0) following successful defibrillation of LDVF after flunarizine was 48% of that in controls (2.7 ± 2.0, P < 0.05). The effect of flunarizine on SDVF‐DFT and LDVF‐DFT indicates that the role of DADs in the defibrillation mechanism may differ as VF continues. Flunarizine significantly reduced early VF recurrence following LDVF, suggesting that DADs potentially contribute to refibrillation in a canine model of prolonged VF.
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Affiliation(s)
- Chaofan Xing
- Department of Cardiology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qi Jin
- Department of Cardiology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ning Zhang
- Department of Cardiology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shaohua Liu
- Department of Cardiology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Changjian Lin
- Department of Cardiology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qiong Wu
- Department of Cardiology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qingzhi Luo
- Department of Cardiology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ao Liu
- Department of Cardiology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Liqun Wu
- Department of Cardiology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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Skulec R, Astapenko D, Cerna Parizkova R, Furst B, Bilska M, Parizek T, Hovanec T, Pinterova N, Knor J, Dudakova J, Truhlar A, Radochova V, Zadak Z, Cerny V. Novel patterns of left ventricular mechanical activity during experimental cardiac arrest in pigs. Physiol Res 2018. [PMID: 29527908 DOI: 10.33549/physiolres.933716] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
We conducted an experimental study to evaluate the presence of coordinated left ventricular mechanical myocardial activity (LVMA) in two types of experimentally induced cardiac arrest: ventricular fibrillation (VF) and pulseless electrical activity (PEA). Twenty anesthetized domestic pigs were randomized 1:1 either to induction of VF or PEA. They were left in nonresuscitated cardiac arrest until the cessation of LVMA and microcirculation. Surface ECG, presence of LVMA by transthoracic echocardiography and sublingual microcirculation were recorded. One minute after induction of cardiac arrest, LVMA was identified in all experimental animals. In the PEA group, rate of LVMA was of 106+/-12/min. In the VF group, we identified two patterns of LVMA. Six animals exhibited contractions of high frequency (VFhigh group), four of low frequency (VFlow group) (334+/-12 vs. 125+/-32/min, p<0.001). A time from cardiac arrest induction to asystole (19.2+/-7.2 vs. 7.3+/-2.2 vs. 8.3+/-5.5 min, p=0.003), cessation of LVMA (11.3+/-5.6 vs. 4.4+/-0.4 vs. 7.4+/-2.9 min, p=0.027) and cessation of microcirculation (25.3+/-12.6 vs. 13.4+/-2.4 vs. 23.2+/-8.7 min, p=0.050) was significantly longer in VFlow group than in VFhigh and PEA group, respectively. Thus, LVMA is present in both VF and PEA type of induced cardiac arrest and moreover, VF may exhibit various patterns of LVMA.
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Affiliation(s)
- R Skulec
- Department of Anesthesiology, Perioperative Medicine and Intensive Care, Masaryk Hospital Usti nad Labem, Usti nad Labem, Czech Republic.
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Cellular Physiology and Clinical Manifestations of Fascicular Arrhythmias in Normal Hearts. JACC Clin Electrophysiol 2017; 3:1343-1355. [PMID: 29759663 DOI: 10.1016/j.jacep.2017.07.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 06/22/2017] [Accepted: 07/27/2017] [Indexed: 11/22/2022]
Abstract
Fascicular ventricular arrhythmias represent a spectrum of ventricular tachycardias dependent on the specialized conduction system. Although they are more common in structurally abnormal hearts, there is an increasing body of literature describing their role in normal hearts. In this review, the authors present data from both basic and clinical research that explore the current understanding of idiopathic fascicular ventricular arrhythmias. Evaluation of the cellular electrophysiology of the Purkinje cells shows clear evidence of enhanced automaticity and triggered activity as potential mechanisms of arrhythmias. Perhaps more importantly, heterogeneity in conduction system velocity and refractoriness of the left ventricular conduction system in animal models are in line with clinical descriptions of re-entrant fascicular arrhythmias in humans. Further advances in our understanding of the conduction system will help bridge the current gap between basic science and clinical fascicular arrhythmias.
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