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Tsuji Y, Yamazaki M, Shimojo M, Yanagisawa S, Inden Y, Murohara T. Mechanisms of torsades de pointes: an update. Front Cardiovasc Med 2024; 11:1363848. [PMID: 38504714 PMCID: PMC10948600 DOI: 10.3389/fcvm.2024.1363848] [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: 12/31/2023] [Accepted: 02/19/2024] [Indexed: 03/21/2024] Open
Abstract
Torsades de Pointes (TdP) refers to a polymorphic ventricular tachycardia (VT) with undulating QRS axis that occurs in long QT syndrome (LQTS), although the term has been used to describe polymorphic ventricular tachyarrhythmias in which QT intervals are not prolonged, such as short-coupled variant of TdP currently known as short-coupled ventricular fibrillation (VF) and Brugada syndrome. Extensive works on LQTS-related TdP over more than 50 years since it was first recognized by Dessertennes who coined the French term meaning "twisting of the points", have led to current understanding of the electrophysiological mechanism that TdP is initiated by triggered activity due to early afterdepolarization (EAD) and maintained by reentry within a substrate of inhomogeneous repolarization. While a recently emerging notion that steep voltage gradients rather than EADs are crucial to generate premature ventricular contractions provides additions to the initiation mode, the research to elucidate the maintenance mechanism hasn't made much progress. The reentrant activity that produces the specific form of VT is not well characterized. We have conducted optical mapping in a rabbit model of electrical storm by electrical remodeling (QT prolongation) due to chronic complete atrioventricular block and demonstrated that a tissue-island with prolonged refractoriness due to enhanced late Na+ current (INa-L) contributes to the generation of drifting rotors in a unique manner, which may explain the ECG characteristic of TdP. Moreover, we have proposed that the neural Na+ channel NaV1.8-mediated INa-L may be a new player to form the substrate for TdP. Here we discuss TdP mechanisms by comparing the findings in electrical storm rabbits with recently published studies by others in simulation models and human and animal models of LQTS.
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Affiliation(s)
- Yukiomi Tsuji
- Departments of Cardiovascular Research and Innovation, Cardiology and Advanced Cardiovascular Therapeutics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Masatoshi Yamazaki
- Department of Cardiology, Nagano Hospital, Soja and Medical Device Development and Regulation Research Center and Department of Precision Engineering, The University of Tokyo, Tokyo, Japan
| | - Masafumi Shimojo
- Departments of Cardiovascular Research and Innovation, Cardiology and Advanced Cardiovascular Therapeutics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Satoshi Yanagisawa
- Departments of Cardiovascular Research and Innovation, Cardiology and Advanced Cardiovascular Therapeutics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yasuya Inden
- Departments of Cardiovascular Research and Innovation, Cardiology and Advanced Cardiovascular Therapeutics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Toyoaki Murohara
- Departments of Cardiovascular Research and Innovation, Cardiology and Advanced Cardiovascular Therapeutics, Nagoya University Graduate School of Medicine, Nagoya, Japan
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Ryckman N, Crinion D, Enriquez A, Bakker D, Chacko S, Abdollah H, Baranchuk A, Simpson C, Redfearn DP. Right atrial collision time (RACT): A novel marker of propensity for typical atrial flutter. J Cardiovasc Electrophysiol 2023; 34:1377-1383. [PMID: 37222182 DOI: 10.1111/jce.15935] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 03/28/2023] [Accepted: 05/04/2023] [Indexed: 05/25/2023]
Abstract
INTRODUCTION The risk of typical atrial flutter (AFL) is increased proportionately to right atrial (RA) size or right atrial scarring that results in reduced conduction velocity. These characteristics result in propagation of a flutter wave by ensuring the macro re-entrant wave front does not meet its refractory tail. The time taken to traverse the circuit would take account of both of these characteristics and may provide a novel marker of propensity to develop AFL. Our goal was to investigate right atrial collision time (RACT) as a marker of existing typical AFL. METHODS This single-centre, prospective study recruited consecutive typical AFL ablation patients that were in sinus rhythm. Controls were consecutive electrophysiology study patients >18 years of age. While pacing the coronary sinus (CS) ostium at 600 ms, a local activation time map was created to locate the latest collision point on the anterolateral right atrial wall. This RACT is a measure of conduction velocity and distance from CS to a collision point on the lateral right atrial wall. RESULTS Ninety-eight patients were included in the analysis, 41 with atrial flutter and 57 controls. Patients with atrial flutter were older, 64.7 ± 9.7 versus 52.4 ± 16.8 years (<.001), and more often male (34/41 vs. 31/57 [.003]). The AFL group mean RACT (132.6 ± 17.3 ms) was significantly longer than that of controls (99.1 ± 11.6 ms) (p < .001). A RACT cut-off of 115.5 ms had a sensitivity and specificity of 92.7% and 93.0%, respectively for diagnosis of atrial flutter. A ROC curve indicated an AUC of 0.96 (95% CI: 0.93-1.0, p < .01). CONCLUSION RACT is a novel and promising marker of propensity for typical AFL. This data will inform larger prospective studies.
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Affiliation(s)
- Nick Ryckman
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
- Department of Medicine, Queen's University, Kingston, Ontario, Canada
- Kingston Health Sciences Centre, Queen's University, Kingston, Ontario, Canada
| | - Derek Crinion
- Department of Medicine, Queen's University, Kingston, Ontario, Canada
- Kingston Health Sciences Centre, Queen's University, Kingston, Ontario, Canada
| | - Andres Enriquez
- Department of Medicine, Queen's University, Kingston, Ontario, Canada
- Kingston Health Sciences Centre, Queen's University, Kingston, Ontario, Canada
| | - David Bakker
- Department of Medicine, Queen's University, Kingston, Ontario, Canada
- Kingston Health Sciences Centre, Queen's University, Kingston, Ontario, Canada
| | - Sanoj Chacko
- Department of Medicine, Queen's University, Kingston, Ontario, Canada
- Kingston Health Sciences Centre, Queen's University, Kingston, Ontario, Canada
| | - Hoshiar Abdollah
- Department of Medicine, Queen's University, Kingston, Ontario, Canada
- Kingston Health Sciences Centre, Queen's University, Kingston, Ontario, Canada
| | - Adrian Baranchuk
- Department of Medicine, Queen's University, Kingston, Ontario, Canada
- Kingston Health Sciences Centre, Queen's University, Kingston, Ontario, Canada
| | - Christopher Simpson
- Department of Medicine, Queen's University, Kingston, Ontario, Canada
- Kingston Health Sciences Centre, Queen's University, Kingston, Ontario, Canada
| | - Damian P Redfearn
- Department of Medicine, Queen's University, Kingston, Ontario, Canada
- Kingston Health Sciences Centre, Queen's University, Kingston, Ontario, Canada
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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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Björnson E, Östlund Y, Ståhlman M, Adiels M, Omerovic E, Jeppsson A, Borén J, Levin MC. Lipid profiling of human diabetic myocardium reveals differences in triglyceride fatty acyl chain length and degree of saturation. Int J Cardiol 2020; 320:106-111. [PMID: 32738258 DOI: 10.1016/j.ijcard.2020.07.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 04/23/2020] [Accepted: 07/13/2020] [Indexed: 01/14/2023]
Abstract
BACKGROUND Type 2 diabetes is a major health problem in the world, and is strongly associated with impaired cardiac function and increased mortality. The causal relationship between type 2 diabetes and impaired cardiac function is still incompletely understood but changes in the cardiac lipid metabolism are believed to be a contributing factor. The objective of this study was to determine the lipid profile in human myocardial biopsies collected in vivo from patients with type 2 diabetes and compare to non-diabetic controls. METHOD We conducted full lipidomics analyses, using mass spectrometry, of 85 right atrial biopsies obtained from diabetic and non-diabetic patients undergoing elective cardiac surgery. The patients were characterized clinically and serum was analyzed for lipids and biochemical markers. RESULTS The groups did not differ in BMI and in circulating triglycerides. We demonstrate that type 2 diabetes is associated with alterations in the cardiac lipidome. Interestingly, the absolute amount of lipids is not altered in the diabetic myocardium. However, triglycerides with longer fatty acyl chains are more abundant and there is a higher degree of unsaturated fatty acid chains in triglycerides in diabetic myocardium. CONCLUSIONS Our study reveals that type 2 diabetes is a relatively strong determinant of the human cardiac lipidome (compared to other clinical variables). Although the total lipid content in the diabetic myocardium is not increased, the lipid composition is markedly affected.
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Affiliation(s)
- Elias Björnson
- Department of Molecular and Clinical Medicine, Wallenberg Laboratory, Institute of Medicine, the Sahlgrenska Academy at University of Gothenburg and Sahlgrenska University Hospital, Sweden
| | - Ylva Östlund
- Department of Molecular and Clinical Medicine, Wallenberg Laboratory, Institute of Medicine, the Sahlgrenska Academy at University of Gothenburg and Sahlgrenska University Hospital, Sweden; Department of Nephrology, Institute of Medicine, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Marcus Ståhlman
- Department of Molecular and Clinical Medicine, Wallenberg Laboratory, Institute of Medicine, the Sahlgrenska Academy at University of Gothenburg and Sahlgrenska University Hospital, Sweden
| | - Martin Adiels
- Department of Molecular and Clinical Medicine, Wallenberg Laboratory, Institute of Medicine, the Sahlgrenska Academy at University of Gothenburg and Sahlgrenska University Hospital, Sweden
| | - Elmir Omerovic
- Department of Molecular and Clinical Medicine, Wallenberg Laboratory, Institute of Medicine, the Sahlgrenska Academy at University of Gothenburg and Sahlgrenska University Hospital, Sweden
| | - Anders Jeppsson
- Department of Molecular and Clinical Medicine, Wallenberg Laboratory, Institute of Medicine, the Sahlgrenska Academy at University of Gothenburg and Sahlgrenska University Hospital, Sweden; Department of Cardiothoracic Surgery, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Jan Borén
- Department of Molecular and Clinical Medicine, Wallenberg Laboratory, Institute of Medicine, the Sahlgrenska Academy at University of Gothenburg and Sahlgrenska University Hospital, Sweden
| | - Malin C Levin
- Department of Molecular and Clinical Medicine, Wallenberg Laboratory, Institute of Medicine, the Sahlgrenska Academy at University of Gothenburg and Sahlgrenska University Hospital, Sweden.
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van Gorp PRR, Trines SA, Pijnappels DA, de Vries AAF. Multicellular In vitro Models of Cardiac Arrhythmias: Focus on Atrial Fibrillation. Front Cardiovasc Med 2020; 7:43. [PMID: 32296716 PMCID: PMC7138102 DOI: 10.3389/fcvm.2020.00043] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 03/06/2020] [Indexed: 12/13/2022] Open
Abstract
Atrial fibrillation (AF) is the most common cardiac arrhythmia in clinical practice with a large socioeconomic impact due to its associated morbidity, mortality, reduction in quality of life and health care costs. Currently, antiarrhythmic drug therapy is the first line of treatment for most symptomatic AF patients, despite its limited efficacy, the risk of inducing potentially life-threating ventricular tachyarrhythmias as well as other side effects. Alternative, in-hospital treatment modalities consisting of electrical cardioversion and invasive catheter ablation improve patients' symptoms, but often have to be repeated and are still associated with serious complications and only suitable for specific subgroups of AF patients. The development and progression of AF generally results from the interplay of multiple disease pathways and is accompanied by structural and functional (e.g., electrical) tissue remodeling. Rational development of novel treatment modalities for AF, with its many different etiologies, requires a comprehensive insight into the complex pathophysiological mechanisms. Monolayers of atrial cells represent a simplified surrogate of atrial tissue well-suited to investigate atrial arrhythmia mechanisms, since they can easily be used in a standardized, systematic and controllable manner to study the role of specific pathways and processes in the genesis, perpetuation and termination of atrial arrhythmias. In this review, we provide an overview of the currently available two- and three-dimensional multicellular in vitro systems for investigating the initiation, maintenance and termination of atrial arrhythmias and AF. This encompasses cultures of primary (animal-derived) atrial cardiomyocytes (CMs), pluripotent stem cell-derived atrial-like CMs and (conditionally) immortalized atrial CMs. The strengths and weaknesses of each of these model systems for studying atrial arrhythmias will be discussed as well as their implications for future studies.
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Affiliation(s)
| | | | | | - Antoine A. F. de Vries
- Laboratory of Experimental Cardiology, Department of Cardiology, Leiden University Medical Center, Leiden, Netherlands
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Narayan SM, Wang PJ, Daubert JP. New Concepts in Sudden Cardiac Arrest to Address an Intractable Epidemic: JACC State-of-the-Art Review. J Am Coll Cardiol 2019; 73:70-88. [PMID: 30621954 PMCID: PMC6398445 DOI: 10.1016/j.jacc.2018.09.083] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 08/28/2018] [Accepted: 09/22/2018] [Indexed: 12/11/2022]
Abstract
Sudden cardiac arrest (SCA) is one of the largest causes of mortality globally, with an out-of-hospital survival below 10% despite intense research. This document outlines challenges in addressing the epidemic of SCA, along the framework of respond, understand and predict, and prevent. Response could be improved by technology-assisted orchestration of community responder systems, access to automated external defibrillators, and innovations to match resuscitation resources to victims in place and time. Efforts to understand and predict SCA may be enhanced by refining taxonomy along phenotypical and pathophysiological "axes of risk," extending beyond cardiovascular pathology to identify less heterogeneous cohorts, facilitated by open-data platforms and analytics including machine learning to integrate discoveries across disciplines. Prevention of SCA must integrate these concepts, recognizing that all members of society are stakeholders. Ultimately, solutions to the public health challenge of SCA will require greater awareness, societal debate and focused public policy.
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Affiliation(s)
- Sanjiv M Narayan
- Department of Medicine, Division of Cardiology, Stanford University, Stanford, California.
| | - Paul J Wang
- Department of Medicine, Division of Cardiology, Stanford University, Stanford, California
| | - James P Daubert
- Department of Medicine, Division of Cardiology, Duke University, Durham, North Carolina
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Roney CH, Ng FS, Debney MT, Eichhorn C, Nachiappan A, Chowdhury RA, Qureshi NA, Cantwell CD, Tweedy JH, Niederer SA, Peters NS, Vigmond EJ. Determinants of new wavefront locations in cholinergic atrial fibrillation. Europace 2018; 20:iii3-iii15. [PMID: 30476057 PMCID: PMC6251188 DOI: 10.1093/europace/euy235] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 10/10/2018] [Indexed: 01/10/2023] Open
Abstract
AIMS Atrial fibrillation (AF) wavefront dynamics are complex and difficult to interpret, contributing to uncertainty about the mechanisms that maintain AF. We aimed to investigate the interplay between rotors, wavelets, and focal sources during fibrillation. METHODS AND RESULTS Arrhythmia wavefront dynamics were analysed for four optically mapped canine cholinergic AF preparations. A bilayer computer model was tuned to experimental preparations, and varied to have (i) fibrosis in both layers or the epicardium only, (ii) different spatial acetylcholine distributions, (iii) different intrinsic action potential duration between layers, and (iv) varied interlayer connectivity. Phase singularities (PSs) were identified and tracked over time to identify rotational drivers. New focal wavefronts were identified using phase contours. Phase singularity density and new wavefront locations were calculated during AF. There was a single dominant mechanism for sustaining AF in each of the preparations, either a rotational driver or repetitive new focal wavefronts. High-density PS sites existed preferentially around the pulmonary vein junctions. Three of the four preparations exhibited stable preferential sites of new wavefronts. Computational simulations predict that only a small number of connections are functionally important in sustaining AF, with new wavefront locations determined by the interplay between fibrosis distribution, acetylcholine concentration, and heterogeneity in repolarization within layers. CONCLUSION We were able to identify preferential sites of new wavefront initiation and rotational activity, in order to determine the mechanisms sustaining AF. Electrical measurements should be interpreted differently according to whether they are endocardial or epicardial recordings.
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Affiliation(s)
- Caroline H Roney
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
- LIRYC Electrophysiology and Heart Modeling Institute, Bordeaux Fondation, Avenue du Haut-Lévèque, Pessac, France
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - Fu Siong Ng
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
| | - Michael T Debney
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
| | - Christian Eichhorn
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
| | - Arun Nachiappan
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
| | - Rasheda A Chowdhury
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
| | - Norman A Qureshi
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
| | - Chris D Cantwell
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
| | - Jennifer H Tweedy
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
| | - Steven A Niederer
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - Nicholas S Peters
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
| | - Edward J Vigmond
- LIRYC Electrophysiology and Heart Modeling Institute, Bordeaux Fondation, Avenue du Haut-Lévèque, Pessac, France
- Univ. Bordeaux, IMB UMR 5251, F-33400 Talence, France
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Shariat MH, Hashemi J, Gazor S, Redfearn DP. Regional Dominant Frequency: A New Tool for Wave Break Identification During Atrial Fibrillation. Front Cardiovasc Med 2018; 5:79. [PMID: 29988509 PMCID: PMC6026623 DOI: 10.3389/fcvm.2018.00079] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 06/08/2018] [Indexed: 12/18/2022] Open
Abstract
Cardiac mapping systems are based on the time/frequency feature analyses of intracardiac electrograms recorded from individual bipolar/unipolar electrodes. Signals from each electrode are processed independently. Such approaches fail to investigate the interrelationship between simultaneously recorded channels of any given mapping catheter during atrial fibrillation (AF). We introduce a novel signal processing technique that reflects regional dominant frequency (RDF) components. We show that RDF can be used to identify and characterize variation and disorganization in wavefront propagation- wave breaks. The intracardiac electrograms from the left atrium of 15 patients were exported to MATLAB and custom software employed to estimate RDF and wave break rate (WBR). We observed a heterogeneous distribution of both RDF and WBR; the two measures were weakly correlated (0.3; p < 0.001). We identified locations of AF or atrial tachycardia (ATach) termination and later compared offline with RDF and WBR maps. We inspected our novel metrics for associations with AF termination sites. Areas associated with AF termination demonstrated high RDF and low WBR (↑RDF,↓WBR). These sites were present in 14 of 15 patients (mean 2.6 ± 1.2 sites per patient; range, 1-4 sites), 43% situated within the pulmonary veins. In nine patients where AF terminated to sinus rhythm (6) or ATach (3), post-hoc analysis demonstrated all ↑RDF,↓WBR sites were ablated and correlated with AF termination sites. The proposed RDF signal processing tools can be used to identify and quantify wave break, and the combined use of these two novel metrics can aid characterization of AF. Further prospective studies are warranted.
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Affiliation(s)
- Mohammad Hassan Shariat
- Department of Medicine, Queen's University, Kingston, ON, Canada
- School of Computing, Queen's University, Kingston, ON, Canada
| | - Javad Hashemi
- School of Computing, Queen's University, Kingston, ON, Canada
| | - Saeed Gazor
- Department of Electrical and Computer Engineering, Queen's University, Kingston, ON, Canada
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Ho G, Villongco CT, Yousefian O, Bradshaw A, Nguyen A, Faiwiszewski Y, Hayase J, Rappel WJ, McCulloch AD, Krummen DE. Rotors exhibit greater surface ECG variation during ventricular fibrillation than focal sources due to wavebreak, secondary rotors, and meander. J Cardiovasc Electrophysiol 2017; 28:1158-1166. [PMID: 28670858 DOI: 10.1111/jce.13283] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Revised: 05/21/2017] [Accepted: 06/06/2017] [Indexed: 01/09/2023]
Abstract
INTRODUCTION Ventricular fibrillation is a common life-threatening arrhythmia. The ECG of VF appears chaotic but may allow identification of sustaining mechanisms to guide therapy. HYPOTHESIS We hypothesized that rotors and focal sources manifest distinct features on the ECG, and computational modeling may identify mechanisms of such features. METHODS VF induction was attempted in 31 patients referred for ventricular arrhythmia ablation. Simultaneous surface ECG and intracardiac electrograms were recorded using biventricular basket catheters. Endocardial phase maps were used to mechanistically classify each VF cycle as rotor or focally driven. ECGs were analyzed from patients demonstrating both mechanisms in the primary analysis and from all patients with induced VF in the secondary analysis. The ECG voltage variation during each mechanism was compared. Biventricular computer simulations of VF driven by focal sources or rotors were created and resulting ECGs of each VF mechanism were compared. RESULTS Rotor-based VF exhibited greater voltage variation than focal source-based VF in both the primary analysis (n = 8, 110 ± 24% vs. 55 ± 32%, P = 0.02) and the secondary analysis (n = 18, 103 ± 30% vs. 67 ± 34%, P = 0.009). Computational VF simulations also revealed greater voltage variation in rotors compared to focal sources (110 ± 19% vs. 33 ± 16%, P = 0.001), and demonstrated that this variation was due to wavebreak, secondary rotor initiation, and rotor meander. CONCLUSION Clinical and computational studies reveal that quantitative criteria of ECG voltage variation differ significantly between VF-sustaining rotors and focal sources, and provide insight into the mechanisms of such variation. Future studies should prospectively evaluate if these criteria can separate clinical VF mechanisms and guide therapy.
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Affiliation(s)
- Gordon Ho
- Department of Medicine, University of California, San Diego, CA, USA.,Veterans Affairs San Diego Healthcare System, San Diego, CA, USA
| | | | - Omid Yousefian
- Department of Medicine, University of Southern California, Los Angeles, CA, USA
| | | | - Andrew Nguyen
- Department of Medicine, University of California, San Diego, CA, USA.,Veterans Affairs San Diego Healthcare System, San Diego, CA, USA
| | - Yonatan Faiwiszewski
- Department of Medicine, University of California, San Diego, CA, USA.,Veterans Affairs San Diego Healthcare System, San Diego, CA, USA
| | - Justin Hayase
- Department of Medicine, University of California, San Diego, CA, USA.,Veterans Affairs San Diego Healthcare System, San Diego, CA, USA
| | | | - Andrew D McCulloch
- Department of Medicine, University of California, San Diego, CA, USA.,Department of Bioengineering, University of California, San Diego, CA, USA
| | - David E Krummen
- Department of Medicine, University of California, San Diego, CA, USA.,Veterans Affairs San Diego Healthcare System, San Diego, CA, USA
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10
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Šmíd J, Rokyta R. Atrial fibrillation and its relation to cardiac diseases and sudden cardiac death. COR ET VASA 2017. [DOI: 10.1016/j.crvasa.2017.06.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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