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Pullinger TK, Sobie EA. Cell-to-cell heterogeneity in ion channel conductance impacts substrate vulnerability to arrhythmia. Am J Physiol Heart Circ Physiol 2024; 327:H242-H254. [PMID: 38758124 PMCID: PMC11381019 DOI: 10.1152/ajpheart.00645.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 05/06/2024] [Accepted: 05/15/2024] [Indexed: 05/18/2024]
Abstract
Determining whether an ectopic depolarization will lead to a self-perpetuating arrhythmia is of critical importance in determining arrhythmia risk, so it is necessary to understand what factors impact substrate vulnerability. This study sought to explore the impact of cell-to-cell heterogeneity in ion channel conductance on substrate vulnerability to arrhythmia by measuring the duration of the vulnerable window in computational models of one-dimensional cables of ventricular cardiomyocytes. We began by using a population of uniform cable models to determine the mechanisms underlying the vulnerable window phenomenon. We found that in addition to the known importance of GNa, the conductances GCa,L and GKr also play a minor role in determining the vulnerable window duration. We also found that a steeper slope of the repolarizing action potential during the vulnerable window correlated with a shorter vulnerable window duration in uniform cables. We applied our understanding from these initial simulations to an investigation of the vulnerable window in heterogeneous cable models. The heterogeneous cables displayed a great deal of intra-cable variation in vulnerable window duration, highly sensitive to the cardiomyocytes in the local environment of the ectopic stimulus. Coupling strength modulated not only the magnitude of the vulnerable window duration but also the extent of intra-tissue variability in vulnerable window duration.NEW & NOTEWORTHY We investigate the impact of cell-to-cell heterogeneity in ion channel conductance on substrate vulnerability to arrhythmia by measuring the vulnerable window duration in computational cardiomyocyte cable models. We demonstrate a wide range of intra-cable variability in vulnerable window duration (VWD) and show how this is changed by ion channel block and coupling strength perturbations.
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Affiliation(s)
- Taylor K Pullinger
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, United States
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, United States
| | - Eric A Sobie
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, United States
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2
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Ertaş K, Gül Ö, Yıldırım R, Özalkak Ş. Evaluation of cardiac electrophysiological features in patients with premature adrenarche. J Pediatr Endocrinol Metab 2024; 37:317-325. [PMID: 38386924 DOI: 10.1515/jpem-2023-0460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Accepted: 02/05/2024] [Indexed: 02/24/2024]
Abstract
OBJECTIVES This study aimed to analyze the cardiac effects of hyperandrogenism in premature adrenarche (PA) and evaluate the risk of arrhythmia development. METHODS Fifty patients with PA and 50 healthy children from a pediatric endocrinology outpatient clinic were included in the study. The patients underwent echocardiography and electrocardiographic evaluations. Conventional echocardiography, tissue Doppler echocardiography, repolarization time, and repolarization dispersion time were evaluated. RESULTS The median age in the PA and control groups was 7.91 years (5.83-9.25), 8.08 years (5.75-9.33), respectively. Thirty percent of patients in the PA group were male. While mitral early diastolic velocity deceleration time (DT), isovolumetric relaxation time (IRT), and E/e' ratio were significantly higher in the PA group than in the control group, mitral lateral annulus tissue Doppler early diastolic velocity was significantly lower (p=0.0001, 0.0001, 0.003, 0.0001). While P wave dispersion (PWD), Tpe, and QT-dispersion (QT-d) values were significantly higher in the PA group than in the control group, the P minimum value was significantly lower in the PA group (p=0.0001, 0.02, 0.004, and 0.0001, respectively). CONCLUSIONS Early subclinical diastolic dysfunction was observed in the PA group. There was an increased risk of atrial arrhythmia with PWD and an increased risk of ventricular arrhythmia with increased Tpe and QT-d. There was a correlation between testosterone levels and diastolic function parameters. The increased risk of atrial arrhythmia is closely related to diastolic function.
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Affiliation(s)
- Kerem Ertaş
- Department of Pediatric Cardiology, 653583 Diyarbakir Children's Hospital , Diyarbakır, Türkiye
| | - Özlem Gül
- Department of Pediatric Cardiology, 653583 Diyarbakir Children's Hospital , Diyarbakır, Türkiye
| | - Ruken Yıldırım
- Department of Pediatric Endocrinology, Hepatology and Nutrition, 653583 Diyarbakir Children's Hospital , Diyarbakır, Türkiye
| | - Şervan Özalkak
- Department of Pediatric Endocrinology, Hepatology and Nutrition, 653583 Diyarbakir Children's Hospital , Diyarbakır, Türkiye
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3
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Zaniboni M. The electrical restitution of the non-propagated cardiac ventricular action potential. Pflugers Arch 2024; 476:9-37. [PMID: 37783868 PMCID: PMC10758374 DOI: 10.1007/s00424-023-02866-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 08/19/2023] [Accepted: 09/21/2023] [Indexed: 10/04/2023]
Abstract
Sudden changes in pacing cycle length are frequently associated with repolarization abnormalities initiating cardiac arrhythmias, and physiologists have long been interested in measuring the likelihood of these events before their manifestation. A marker of repolarization stability has been found in the electrical restitution (ER), the response of the ventricular action potential duration to a pre- or post-mature stimulation, graphically represented by the so-called ER curve. According to the restitution hypothesis (ERH), the slope of this curve provides a quantitative discrimination between stable repolarization and proneness to arrhythmias. ER has been studied at the body surface, whole organ, and tissue level, and ERH has soon become a key reference point in theoretical, clinical, and pharmacological studies concerning arrhythmia development, and, despite criticisms, it is still widely adopted. The ionic mechanism of ER and cellular applications of ERH are covered in the present review. The main criticism on ERH concerns its dependence from the way ER is measured. Over the years, in fact, several different experimental protocols have been established to measure ER, which are also described in this article. In reviewing the state-of-the art on cardiac cellular ER, I have introduced a notation specifying protocols and graphical representations, with the aim of unifying a sometime confusing nomenclature, and providing a physiological tool, better defined in its scope and limitations, to meet the growing expectations of clinical and pharmacological research.
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Affiliation(s)
- Massimiliano Zaniboni
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma (Italy), Parco Area Delle Scienze, 11/A, 43124, Parma, Italy.
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4
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Venkateshappa R, Hunter DV, Muralidharan P, Nagalingam RS, Huen G, Faizi S, Luthra S, Lin E, Cheng YM, Hughes J, Khelifi R, Dhunna DP, Johal R, Sergeev V, Shafaattalab S, Julian LM, Poburko DT, Laksman Z, Tibbits GF, Claydon TW. Targeted activation of human ether-à-go-go-related gene channels rescues electrical instability induced by the R56Q+/- long QT syndrome variant. Cardiovasc Res 2023; 119:2522-2535. [PMID: 37739930 PMCID: PMC10676460 DOI: 10.1093/cvr/cvad155] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 06/22/2023] [Accepted: 07/10/2023] [Indexed: 09/24/2023] Open
Abstract
AIMS Long QT syndrome type 2 (LQTS2) is associated with inherited variants in the cardiac human ether-à-go-go-related gene (hERG) K+ channel. However, the pathogenicity of hERG channel gene variants is often uncertain. Using CRISPR-Cas9 gene-edited hiPSC-derived cardiomyocytes (hiPSC-CMs), we investigated the pathogenic mechanism underlying the LQTS-associated hERG R56Q variant and its phenotypic rescue by using the Type 1 hERG activator, RPR260243. METHODS AND RESULTS The above approaches enable characterization of the unclear causative mechanism of arrhythmia in the R56Q variant (an N-terminal PAS domain mutation that primarily accelerates channel deactivation) and translational investigation of the potential for targeted pharmacologic manipulation of hERG deactivation. Using perforated patch clamp electrophysiology of single hiPSC-CMs, programmed electrical stimulation showed that the hERG R56Q variant does not significantly alter the mean action potential duration (APD90). However, the R56Q variant increases the beat-to-beat variability in APD90 during pacing at constant cycle lengths, enhances the variance of APD90 during rate transitions, and increases the incidence of 2:1 block. During paired S1-S2 stimulations measuring electrical restitution properties, the R56Q variant was also found to increase the variability in rise time and duration of the response to premature stimulations. Application of the hERG channel activator, RPR260243, reduces the APD variance in hERG R56Q hiPSC-CMs, reduces the variability in responses to premature stimulations, and increases the post-repolarization refractoriness. CONCLUSION Based on our findings, we propose that the hERG R56Q variant leads to heterogeneous APD dynamics, which could result in spatial dispersion of repolarization and increased risk for re-entry without significantly affecting the average APD90. Furthermore, our data highlight the antiarrhythmic potential of targeted slowing of hERG deactivation gating, which we demonstrate increases protection against premature action potentials and reduces electrical heterogeneity in hiPSC-CMs.
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Affiliation(s)
- Ravichandra Venkateshappa
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada V5A 1S6
| | - Diana V Hunter
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada V5A 1S6
| | - Priya Muralidharan
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada V5A 1S6
| | - Raghu S Nagalingam
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada V5A 1S6
- Cellular and Regenerative Medicine Centre, British Columbia Children’s Hospital Research Institute, 938 W 28th Ave, Vancouver, BC, Canada V5Z 4H4
| | - Galvin Huen
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada V5A 1S6
| | - Shoaib Faizi
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada V5A 1S6
| | - Shreya Luthra
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada V5A 1S6
| | - Eric Lin
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada V5A 1S6
| | - Yen May Cheng
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada V5A 1S6
| | - Julia Hughes
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada V5A 1S6
| | - Rania Khelifi
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada V5A 1S6
| | - Daman Parduman Dhunna
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada V5A 1S6
| | - Raj Johal
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada V5A 1S6
| | - Valentine Sergeev
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada V5A 1S6
| | - Sanam Shafaattalab
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada V5A 1S6
| | - Lisa M Julian
- Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada V5A 1S6
| | - Damon T Poburko
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada V5A 1S6
| | - Zachary Laksman
- Department of Medicine, School of Biomedical Engineering, University of British Columbia, 2194 Health Sciences Mall, Vancouver, BC, Canada V6T 1Z3
| | - Glen F Tibbits
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada V5A 1S6
- Cellular and Regenerative Medicine Centre, British Columbia Children’s Hospital Research Institute, 938 W 28th Ave, Vancouver, BC, Canada V5Z 4H4
- Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada V5A 1S6
| | - Tom W Claydon
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada V5A 1S6
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Campos FO, Shiferaw Y, Whitaker J, Plank G, Bishop MJ. Subthreshold delayed afterdepolarizations provide an important arrhythmogenic substrate in the border zone of infarcted hearts. Heart Rhythm 2023; 20:299-306. [PMID: 36343889 DOI: 10.1016/j.hrthm.2022.10.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 10/26/2022] [Accepted: 10/31/2022] [Indexed: 11/08/2022]
Affiliation(s)
- Fernando O Campos
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom.
| | - Yohannes Shiferaw
- Department of Physics, University of California, Los Angeles, California
| | - John Whitaker
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Gernot Plank
- Gottfried Schatz Research Center, Division of Biophysics, Medical University of Graz, Graz, Austria
| | - Martin J Bishop
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
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Krijger Juárez C, Amin AS, Offerhaus JA, Bezzina CR, Boukens BJ. Cardiac Repolarization in Health and Disease. JACC Clin Electrophysiol 2023; 9:124-138. [PMID: 36697193 DOI: 10.1016/j.jacep.2022.09.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 09/16/2022] [Accepted: 09/21/2022] [Indexed: 12/03/2022]
Abstract
Abnormal cardiac repolarization is at the basis of life-threatening arrhythmias in various congenital and acquired cardiac diseases. Dysfunction of ion channels involved in repolarization at the cellular level are often the underlying cause of the repolarization abnormality. The expression pattern of the gene encoding the affected ion channel dictates its impact on the shape of the T-wave and duration of the QT interval, thereby setting the stage for both the occurrence of the trigger and the substrate for maintenance of the arrhythmia. Here we discuss how research into the genetic and electrophysiological basis of repolarization has provided us with insights into cardiac repolarization in health and disease and how this in turn may provide the basis for future improved patient-specific management.
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Affiliation(s)
- Christian Krijger Juárez
- Department of Experimental Cardiology, Amsterdam University Medical Center, Amsterdam, the Netherlands
| | - Ahmad S Amin
- Department of Cardiology, Amsterdam University Medical Center, Amsterdam, the Netherlands
| | - Joost A Offerhaus
- Department of Experimental Cardiology, Amsterdam University Medical Center, Amsterdam, the Netherlands
| | - Connie R Bezzina
- Department of Experimental Cardiology, Amsterdam University Medical Center, Amsterdam, the Netherlands
| | - Bastiaan J Boukens
- Department of Medical Biology, Amsterdam University Medical Center, Amsterdam, the Netherlands; Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, the Netherlands.
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7
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Cluitmans MJM, Bayer J, Bear LR, ter Bekke RMA, Heijman J, Coronel R, Volders PGA. The circle of reentry: Characteristics of trigger-substrate interaction leading to sudden cardiac arrest. Front Cardiovasc Med 2023; 10:1121517. [PMID: 37139119 PMCID: PMC10150924 DOI: 10.3389/fcvm.2023.1121517] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Accepted: 03/28/2023] [Indexed: 05/05/2023] Open
Abstract
Sudden cardiac death is often caused by ventricular arrhythmias driven by reentry. Comprehensive characterization of the potential triggers and substrate in survivors of sudden cardiac arrest has provided insights into the trigger-substrate interaction leading to reentry. Previously, a "Triangle of Arrhythmogenesis", reflecting interactions between substrate, trigger and modulating factors, has been proposed to reason about arrhythmia initiation. Here, we expand upon this concept by separating the trigger and substrate characteristics in their spatial and temporal components. This yields four key elements that are required for the initiation of reentry: local dispersion of excitability (e.g., the presence of steep repolarization time gradients), a critical relative size of the region of excitability and the region of inexcitability (e.g., a sufficiently large region with early repolarization), a trigger that originates at a time when some tissue is excitable and other tissue is inexcitable (e.g., an early premature complex), and which occurs from an excitable region (e.g., from a region with early repolarization). We discuss how these findings yield a new mechanistic framework for reasoning about reentry initiation, the "Circle of Reentry." In a patient case of unexplained ventricular fibrillation, we then illustrate how a comprehensive clinical investigation of these trigger-substrate characteristics may help to understand the associated arrhythmia mechanism. We will also discuss how this reentry initiation concept may help to identify patients at risk, and how similar reasoning may apply to other reentrant arrhythmias.
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Affiliation(s)
- Matthijs J. M. Cluitmans
- Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands
- Philips Research, Eindhoven, Netherlands
- Correspondence: Matthijs J. M. Cluitmans
| | | | | | - Rachel M. A. ter Bekke
- Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands
| | - Jordi Heijman
- Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands
| | - Ruben Coronel
- Department of Experimental Cardiology, Amsterdam University Medical Centre, Amsterdam, Netherlands
| | - Paul G. A. Volders
- Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands
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8
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Nagy N, Tóth N, Nánási PP. Antiarrhythmic and Inotropic Effects of Selective Na +/Ca 2+ Exchanger Inhibition: What Can We Learn from the Pharmacological Studies? Int J Mol Sci 2022; 23:ijms232314651. [PMID: 36498977 PMCID: PMC9736231 DOI: 10.3390/ijms232314651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 11/15/2022] [Accepted: 11/16/2022] [Indexed: 11/25/2022] Open
Abstract
Life-long stable heart function requires a critical balance of intracellular Ca2+. Several ion channels and pumps cooperate in a complex machinery that controls the influx, release, and efflux of Ca2+. Probably one of the most interesting and most complex players of this crosstalk is the Na+/Ca2+ exchanger, which represents the main Ca2+ efflux mechanism; however, under some circumstances, it can also bring Ca2+ into the cell. Therefore, the inhibition of the Na+/Ca2+ exchanger has emerged as one of the most promising possible pharmacological targets to increase Ca2+ levels, to decrease arrhythmogenic depolarizations, and to reduce excessive Ca2+ influx. In line with this, as a response to increasing demand, several more or less selective Na+/Ca2+ exchanger inhibitor compounds have been developed. In the past 20 years, several results have been published regarding the effect of Na+/Ca2+ exchanger inhibition under various circumstances, e.g., species, inhibitor compounds, and experimental conditions; however, the results are often controversial. Does selective Na+/Ca2+ exchanger inhibition have any future in clinical pharmacological practice? In this review, the experimental results of Na+/Ca2+ exchanger inhibition are summarized focusing on the data obtained by novel highly selective inhibitors.
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Affiliation(s)
- Norbert Nagy
- ELKH-SZTE Research Group of Cardiovascular Pharmacology, 6720 Szeged, Hungary
- Department of Pharmacology and Pharmacotherapy, Albert Szent-Györgyi Medical School, University of Szeged, 6720 Szeged, Hungary
- Correspondence: ; Tel.: +36-62-545-682; Fax: +36-62-545-680
| | - Noémi Tóth
- ELKH-SZTE Research Group of Cardiovascular Pharmacology, 6720 Szeged, Hungary
| | - Péter P. Nánási
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
- Department of Dental Physiology and Pharmacology, Faculty of Dentistry, University of Debrecen, 4032 Debrecen, Hungary
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9
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Computational Re-Entry Vulnerability Index Mapping to Guide Ablation in Patients With Post-Myocardial Infarction Ventricular Tachycardia. JACC Clin Electrophysiol 2022; 9:301-310. [PMID: 36752477 DOI: 10.1016/j.jacep.2022.10.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 09/07/2022] [Accepted: 10/03/2022] [Indexed: 12/02/2022]
Abstract
BACKGROUND Ventricular tachycardias (VTs) in patients with myocardial infarction (MI) are often treated with catheter ablation. However, the VT induction during this procedure does not always identify all of the relevant activation pathways or may not be possible or tolerated. The re-entry vulnerability index (RVI) quantifies regional activation-repolarization differences and can detect multiple regions susceptible to re-entry without the need to induce the arrhythmia. OBJECTIVES This study aimed to further develop and validate the RVI mapping in patient-specific computational models of post-MI VTs. METHODS Cardiac magnetic resonance imaging data from 4 patients with post-MI VTs were used to induce VTs in a computational electrophysiological model by pacing. The RVI map of a premature beat in each patient model was used to guide virtual ablations. We compared our results with those of clinical ablation in the same patients. RESULTS Single-site virtual RVI-guided ablation prevented VT induction in 3 of 9 cases. Multisite virtual ablations guided by RVI mapping successfully prevented re-entry in all cases (9 of 9). Overall, virtual ablation required 15-fold fewer ablation sites (235.5 ± 97.4 vs 17 ± 6.8) and 2-fold less ablation volume (5.34 ± 1.79 mL vs 2.11 ± 0.65 mL) than the clinical ablation. CONCLUSIONS RVI mapping allows localization of multiple regions susceptible to re-entry and may help guide VT ablation. RVI mapping does not require the induction of arrhythmia and may result in less ablated myocardial volumes with fewer ablation sites.
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10
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Campos FO, Neic A, Mendonca Costa C, Whitaker J, O'Neill M, Razavi R, Rinaldi CA, DanielScherr, Niederer SA, Plank G, Bishop MJ. An automated near-real time computational method for induction and treatment of scar-related ventricular tachycardias. Med Image Anal 2022; 80:102483. [PMID: 35667328 PMCID: PMC10114098 DOI: 10.1016/j.media.2022.102483] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 04/22/2022] [Accepted: 05/20/2022] [Indexed: 02/05/2023]
Abstract
Catheter ablation is currently the only curative treatment for scar-related ventricular tachycardias (VTs). However, not only are ablation procedures long, with relatively high risk, but success rates are punitively low, with frequent VT recurrence. Personalized in-silico approaches have the opportunity to address these limitations. However, state-of-the-art reaction diffusion (R-D) simulations of VT induction and subsequent circuits used for in-silico ablation target identification require long execution times, along with vast computational resources, which are incompatible with the clinical workflow. Here, we present the Virtual Induction and Treatment of Arrhythmias (VITA), a novel, rapid and fully automated computational approach that uses reaction-Eikonal methodology to induce VT and identify subsequent ablation targets. The rationale for VITA is based on finding isosurfaces associated with an activation wavefront that splits in the ventricles due to the presence of an isolated isthmus of conduction within the scar; once identified, each isthmus may be assessed for their vulnerability to sustain a reentrant circuit, and the corresponding exit site automatically identified for potential ablation targeting. VITA was tested on a virtual cohort of 7 post-infarcted porcine hearts and the results compared to R-D simulations. Using only a standard desktop machine, VITA could detect all scar-related VTs, simulating activation time maps and ECGs (for clinical comparison) as well as computing ablation targets in 48 minutes. The comparable VTs probed by the R-D simulations took 68.5 hours on 256 cores of high-performance computing infrastructure. The set of lesions computed by VITA was shown to render the ventricular model VT-free. VITA could be used in near real-time as a complementary modality aiding in clinical decision-making in the treatment of post-infarction VTs.
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Affiliation(s)
- Fernando O Campos
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom.
| | | | - Caroline Mendonca Costa
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - John Whitaker
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom; Guy's and St. Thomas' NHS Foundation Trust, Cardiovascular Directorate
| | - Mark O'Neill
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom; Guy's and St. Thomas' NHS Foundation Trust, Cardiovascular Directorate
| | - Reza Razavi
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Christopher A Rinaldi
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom; Guy's and St. Thomas' NHS Foundation Trust, Cardiovascular Directorate
| | - DanielScherr
- Division of Cardiology, Department of Internal Medicine, Medical University of Graz, Austria
| | - Steven A Niederer
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Gernot Plank
- Gottfried Schatz Research Center Biophysics, Medical University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Martin J Bishop
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
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11
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Callans DJ, Donahue JK. Repolarization Heterogeneity in Human Post-Infarct Ventricular Tachycardia. JACC Clin Electrophysiol 2022; 8:713-718. [PMID: 35738846 DOI: 10.1016/j.jacep.2022.03.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 03/01/2022] [Accepted: 03/02/2022] [Indexed: 11/30/2022]
Abstract
BACKGROUND Slow conduction, caused by fibrosis between surviving myocytes and connexin remodeling, is an important prerequisite for post-infarction ventricular tachycardia (VT); however, slow conduction is present throughout the infarct whereas VT circuits are finite in number and discrete. In a porcine model of VT, re-entrant circuits occur at region of significant repolarization heterogeneity caused by up-regulation of potassium channel β-subunits KCNE3 (increasing repolarization current) and KCNE4 (decreasing repolarization current), causing heterogeneous action potential durations. OBJECTIVES This study was designed to determine whether re-entrant circuits in human post-infarction VT are associated with repolarization heterogeneity. METHODS In 6 patients, left ventricular mapping was performed during induced VT to identify sites within the VT circuit. Subsequently, unipolar mapping (3.5-mm tip ablation catheter) was performed to characterize activation-recovery intervals (ARIs), which are surrogates for local action potential durations, at sites documented within the VT circuit isthmus (IN) compared to sites within the infarct scar but outside of the VT circuit (OUT). RESULTS ARIs were significantly shorter in the IN compared with the OUT sites (420.2 ± 79.3 ms vs 462 ± 52.8 ms; P = 0.01). In all patients. sites that were associated with the circuit always had shorter ARI values than did those sampled from OUT regions. CONCLUSIONS VT circuit sites in human post-infarct VT are associated with repolarization heterogeneity, similar to what was previously reported in a porcine model. This suggests the possibility of a common mechanism between humans and the porcine model of post-infarct VT, and that development of ablation strategies or small molecule or genetic therapies to restore normal repolarization kinetics may be antiarrhythmic.
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Affiliation(s)
- David J Callans
- Cardiac Electrophysiology Section, Cardiovascular Medicine Division, Department of Medicine of the University of Pennsylvania, Philadelphia, Pennsylvania, USA.
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12
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Lambiase PD. Rediscovering Repolarization: Timing Is Everything. JACC Clin Electrophysiol 2022; 8:719-721. [PMID: 35738847 DOI: 10.1016/j.jacep.2022.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 04/08/2022] [Accepted: 04/08/2022] [Indexed: 11/27/2022]
Affiliation(s)
- Pier D Lambiase
- University College London Institute of Cardiovascular Science, Barts Heart Centre, London, United Kingdom.
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13
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Elliott MK, Costa CM, Whitaker J, Gemmell P, Mehta VS, Sidhu BS, Gould J, Williams SE, O'Neill M, Razavi R, Niederer S, Bishop MJ, Rinaldi CA. Effect of scar and pacing location on repolarization in a porcine myocardial infarction model. Heart Rhythm O2 2022; 3:186-195. [PMID: 35496454 PMCID: PMC9043407 DOI: 10.1016/j.hroo.2022.01.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Background The effect of chronic ischemic scar on repolarization is unclear, with conflicting results from human and animal studies. An improved understanding of electrical remodeling within scar and border zone tissue may enhance substrate-guided ablation techniques for treatment of ventricular tachycardia. Computational modeling studies have suggested increased dispersion of repolarization during epicardial, but not endocardial, left ventricular pacing, in close proximity to scar. However, the effect of endocardial pacing near scar in vivo is unknown. Objective The purpose of this study was to investigate the effect of scar and pacing location on local repolarization in a porcine myocardial infarction model. Methods Six model pigs underwent late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) imaging followed by electroanatomic mapping of the left ventricular endocardium. LGE-CMR images were registered to the anatomic shell and scar defined by LGE. Activation recovery intervals (ARIs), a surrogate for action potential duration, and local ARI gradients were calculated from unipolar electrograms within areas of late gadolinium enhancement (aLGE) and healthy myocardium. Results There was no significant difference between aLGE and healthy myocardium in mean ARI (304.20 ± 19.44 ms vs 300.59 ± 19.22 ms; P = .43), ARI heterogeneity (23.32 ± 11.43 ms vs 24.85 ± 12.99 ms; P = .54), or ARI gradients (6.18 ± 2.09 vs 5.66 ± 2.32 ms/mm; P = .39). Endocardial pacing distance from scar did not affect ARI gradients. Conclusion Our findings suggest that changes in ARI are not an intrinsic property of surviving myocytes within scar, and endocardial pacing close to scar does not affect local repolarization.
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Affiliation(s)
- Mark K Elliott
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
- Department of Cardiology, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom
| | - Caroline Mendonca Costa
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - John Whitaker
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
- Department of Cardiology, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom
| | - Philip Gemmell
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Vishal S Mehta
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
- Department of Cardiology, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom
| | - Baldeep S Sidhu
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
- Department of Cardiology, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom
| | - Justin Gould
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
- Department of Cardiology, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom
| | - Steven E Williams
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Mark O'Neill
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
- Department of Cardiology, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom
| | - Reza Razavi
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Steven Niederer
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Martin J Bishop
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Christopher A Rinaldi
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
- Department of Cardiology, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom
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14
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Nguyen HX, Wu T, Needs D, Zhang H, Perelli RM, DeLuca S, Yang R, Pan M, Landstrom AP, Henriquez C, Bursac N. Engineered bacterial voltage-gated sodium channel platform for cardiac gene therapy. Nat Commun 2022; 13:620. [PMID: 35110560 PMCID: PMC8810800 DOI: 10.1038/s41467-022-28251-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 01/11/2022] [Indexed: 12/19/2022] Open
Abstract
Therapies for cardiac arrhythmias could greatly benefit from approaches to enhance electrical excitability and action potential conduction in the heart by stably overexpressing mammalian voltage-gated sodium channels. However, the large size of these channels precludes their incorporation into therapeutic viral vectors. Here, we report a platform utilizing small-size, codon-optimized engineered prokaryotic sodium channels (BacNav) driven by muscle-specific promoters that significantly enhance excitability and conduction in rat and human cardiomyocytes in vitro and adult cardiac tissues from multiple species in silico. We also show that the expression of BacNav significantly reduces occurrence of conduction block and reentrant arrhythmias in fibrotic cardiac cultures. Moreover, functional BacNav channels are stably expressed in healthy mouse hearts six weeks following intravenous injection of self-complementary adeno-associated virus (scAAV) without causing any adverse effects on cardiac electrophysiology. The large diversity of prokaryotic sodium channels and experimental-computational platform reported in this study should facilitate the development and evaluation of BacNav-based gene therapies for cardiac conduction disorders.
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Affiliation(s)
- Hung X Nguyen
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Tianyu Wu
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Daniel Needs
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Hengtao Zhang
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Robin M Perelli
- Department of Pediatrics, Division of Cardiology, Duke University School of Medicine, Durham, NC, USA
- Department of Cell Biology, Duke University School of Medicine, Durham, NC, USA
| | - Sophia DeLuca
- Department of Cell Biology, Duke University School of Medicine, Durham, NC, USA
| | - Rachel Yang
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Michael Pan
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Andrew P Landstrom
- Department of Pediatrics, Division of Cardiology, Duke University School of Medicine, Durham, NC, USA
- Department of Cell Biology, Duke University School of Medicine, Durham, NC, USA
| | - Craig Henriquez
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Nenad Bursac
- Department of Biomedical Engineering, Duke University, Durham, NC, USA.
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15
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Terminal T-wave inversion predicts reperfusion tachyarrhythmias in STEMI. J Electrocardiol 2022; 71:28-31. [PMID: 35026678 DOI: 10.1016/j.jelectrocard.2021.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 11/15/2021] [Accepted: 12/23/2021] [Indexed: 11/21/2022]
Abstract
INTRODUCTION A reliable electrocardiographic predictor of ventricular fibrillation (VF) in patients with ST elevation myocardial infarction (STEMI) is lacking so far. Previous experimental/simulation study suggested a terminal T-wave inversion (TTWI) in ischemia-related ECG leads corresponding to anterior infarct localization as an independent predictor of reperfusion VF (rVF). This T-wave characteristic has never been tested as a rVF predictor in clinical settings. The aim of this study was to test if terminal T-wave inversion (TTWI) at admission ECG (before reperfusion) can serve as a predictor of ventricular fibrillation during reperfusion (rVF) in patients with anterior STEMI undergoing primary PCI. METHODS AND RESULTS Study population included consecutive patients with anterior infarct localization admitted for primary PCI (n = 181, age 65 [57; 76] years, 66% male). Of those, 14 patients had rVF (rVF group, age 59 [47; 76] years, 64% male) and patients without rVF comprised the No-rVF group (n = 167, age 65 [57; 76] years, 66% male). Association of TTWI with rVF was analyzed using logistic regression analysis adjusted for relevant clinical and electrocardiographic covariates. The prevalence of TTWI in rVF group was 62% comparing to 23% in the No-rVF group, p = 0.005. TTWI was associated with increased risk of rVF (OR 5.51; 95% CI 1.70-17.89; p = 0.004) and remained a significant predictor after adjustment for age, gender, history of MI prior to index admission, VF before reperfusion, Tpeak-Tend, maximal ST elevation, and QRS duration (OR 23.49; 95% CI 3.14-175.91; p = 0.002). CONCLUSIONS The terminal T-wave inversion in anterior leads before PCI independently predicted rVF in patients with anterior MI thus confirming the previous experimental/simulation findings.
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16
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Odening KE, van der Linde HJ, Ackerman MJ, Volders PGA, ter Bekke RMA. OUP accepted manuscript. Eur Heart J 2022; 43:3018-3028. [PMID: 35445703 PMCID: PMC9443984 DOI: 10.1093/eurheartj/ehac135] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 02/23/2022] [Accepted: 03/03/2022] [Indexed: 11/13/2022] Open
Abstract
An abundance of literature describes physiological and pathological determinants of cardiac performance, building on the principles of excitation–contraction coupling. However, the mutual influencing of excitation–contraction and mechano-electrical feedback in the beating heart, here designated ‘electromechanical reciprocity’, remains poorly recognized clinically, despite the awareness that external and cardiac-internal mechanical stimuli can trigger electrical responses and arrhythmia. This review focuses on electromechanical reciprocity in the long-QT syndrome (LQTS), historically considered a purely electrical disease, but now appreciated as paradigmatic for the understanding of mechano-electrical contributions to arrhythmogenesis in this and other cardiac conditions. Electromechanical dispersion in LQTS is characterized by heterogeneously prolonged ventricular repolarization, besides altered contraction duration and relaxation. Mechanical alterations may deviate from what would be expected from global and regional repolarization abnormalities. Pathological repolarization prolongation outlasts mechanical systole in patients with LQTS, yielding a negative electromechanical window (EMW), which is most pronounced in symptomatic patients. The electromechanical window is a superior and independent arrhythmia-risk predictor compared with the heart rate-corrected QT. A negative EMW implies that the ventricle is deformed—by volume loading during the rapid filling phase—when repolarization is still ongoing. This creates a ‘sensitized’ electromechanical substrate, in which inadvertent electrical or mechanical stimuli such as local after-depolarizations, after-contractions, or dyssynchrony can trigger abnormal impulses. Increased sympathetic-nerve activity and pause-dependent potentiation further exaggerate electromechanical heterogeneities, promoting arrhythmogenesis. Unraveling electromechanical reciprocity advances the understanding of arrhythmia formation in various conditions. Real-time image integration of cardiac electrophysiology and mechanics offers new opportunities to address challenges in arrhythmia management.
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Affiliation(s)
| | - Henk J van der Linde
- Janssen Research & Development, Division of Janssen Pharmaceutica N.V., Beerse, Belgium
| | - Michael J Ackerman
- Department of Cardiovascular Medicine, Division of Heart Rhythm Services (Windland Smith Rice Genetic Heart Rhythm Clinic), Mayo Clinic, Rochester, MN, USA
- Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology, Mayo Clinic, Rochester, MN, USA
- Department of Molecular Pharmacology & Experimental Therapeutics (Windland Smith Rice Sudden Death Genomics Laboratory), Mayo Clinic, Rochester, MN, USA
| | - Paul G A Volders
- Department of Cardiology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University Medical Center+, P. Debyelaan 25, 6229 HX, Maastricht, The Netherlands
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17
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Gottlieb LA, Belterman C, van Amersfoorth S, Loyer V, Constantin M, Hocini M, Dekker LRC, Coronel R. Profibrillatory Structural and Functional Properties of the Atrial-Pulmonary Junction in the Absence of Remodeling. Front Physiol 2021; 12:748203. [PMID: 34899379 PMCID: PMC8654241 DOI: 10.3389/fphys.2021.748203] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 10/18/2021] [Indexed: 11/26/2022] Open
Abstract
Background: Sole pulmonary vein (PV) isolation by ablation therapy prevents atrial fibrillation (AF) in patients with short episodes of AF and without comorbidities. Since incomplete PV isolation can be curative, we tested the hypothesis that the PV in the absence of remodeling and comorbidities contains structural and functional properties that are proarrhythmic for AF initiation by reentry. Methods: We performed percutaneous transvenous in vivo endocardial electrophysiological studies and quantitative histological analysis of PV from healthy sheep. Results: The proximal PV contained more myocytes than the distal PV and a higher percentage of collagen and fat tissue relative to myocytes than the left atrium. Local fractionated electrograms occurred in both the distal and proximal PVs, but a large local activation (>0.75 mV) was more often present in the proximal PV than in the distal PV (86 vs. 50% of electrograms, respectively, p = 0.017). Atrial arrhythmias (run of premature atrial complexes) occurred more often following the premature stimulation in the proximal PV than in the distal PV (p = 0.004). The diastolic stimulation threshold was higher in the proximal PV than in the distal PV (0.7 [0.3] vs. 0.4 [0.2] mA, (median [interquartile range]), p = 0.004). The refractory period was shorter in the proximal PV than in the distal PV (170 [50] vs. 248 [52] ms, p < 0.001). A linear relation existed between the gradient in refractoriness (distal-proximal) and atrial arrhythmia inducibility in the proximal PV. Conclusion: The structural and functional properties of the native atrial-PV junction differ from those of the distal PV. Atrial arrhythmias in the absence of arrhythmia-induced remodeling are caused by reentry in the atrial-PV junction. Ablative treatment of early paroxysmal AF, rather than complete isolation of focal arrhythmia, may be limited to inhibition of reentry.
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Affiliation(s)
- Lisa A Gottlieb
- Department of Experimental Cardiology, Location Academic Medical Centre, Amsterdam University Medical Centre, Amsterdam, Netherlands.,IHU Liryc, University of Bordeaux, Bordeaux, France
| | - Charly Belterman
- Department of Experimental Cardiology, Location Academic Medical Centre, Amsterdam University Medical Centre, Amsterdam, Netherlands
| | - Shirley van Amersfoorth
- Department of Experimental Cardiology, Location Academic Medical Centre, Amsterdam University Medical Centre, Amsterdam, Netherlands
| | | | | | | | - Lukas R C Dekker
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands.,Department of Cardiology, Catharina Hospital, Eindhoven, Netherlands
| | - Ruben Coronel
- Department of Experimental Cardiology, Location Academic Medical Centre, Amsterdam University Medical Centre, Amsterdam, Netherlands.,IHU Liryc, University of Bordeaux, Bordeaux, France
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18
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Cluitmans MJM, Bear LR, Nguyên UC, van Rees B, Stoks J, Ter Bekke RMA, Mihl C, Heijman J, Lau KD, Vigmond E, Bayer J, Belterman CNW, Abell E, Labrousse L, Rogier J, Bernus O, Haïssaguerre M, Hassink RJ, Dubois R, Coronel R, Volders PGA. Noninvasive detection of spatiotemporal activation-repolarization interactions that prime idiopathic ventricular fibrillation. Sci Transl Med 2021; 13:eabi9317. [PMID: 34788076 DOI: 10.1126/scitranslmed.abi9317] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Matthijs J M Cluitmans
- Cardiovascular Research Institute Maastricht, Maastricht University, 6200 MD Maastricht, Netherlands.,Philips Research, 5656 AE Eindhoven, Netherlands
| | | | - Uyên C Nguyên
- Cardiovascular Research Institute Maastricht, Maastricht University, 6200 MD Maastricht, Netherlands
| | - Bianca van Rees
- Cardiovascular Research Institute Maastricht, Maastricht University, 6200 MD Maastricht, Netherlands
| | - Job Stoks
- Cardiovascular Research Institute Maastricht, Maastricht University, 6200 MD Maastricht, Netherlands
| | - Rachel M A Ter Bekke
- Cardiovascular Research Institute Maastricht, Maastricht University, 6200 MD Maastricht, Netherlands
| | - Casper Mihl
- Cardiovascular Research Institute Maastricht, Maastricht University, 6200 MD Maastricht, Netherlands.,Department of Radiology, Maastricht University Medical Centre, 6200 MD Maastricht, Netherlands
| | - Jordi Heijman
- Cardiovascular Research Institute Maastricht, Maastricht University, 6200 MD Maastricht, Netherlands
| | - Kevin D Lau
- Philips Research, 5656 AE Eindhoven, Netherlands
| | | | | | - Charly N W Belterman
- Department of Experimental Cardiology, Amsterdam University Medical Centre, 1105 AZ Amsterdam, Netherlands
| | | | - Louis Labrousse
- IHU LIRYC, 33600 Pessac, France.,University of Bordeaux, 33000 Bordeaux, France.,Hôpital Haut Lévêque, University Hospital of Bordeaux, 33604 Bordeaux, France
| | - Julien Rogier
- IHU LIRYC, 33600 Pessac, France.,University of Bordeaux, 33000 Bordeaux, France.,Hôpital Haut Lévêque, University Hospital of Bordeaux, 33604 Bordeaux, France
| | - Olivier Bernus
- IHU LIRYC, 33600 Pessac, France.,University of Bordeaux, 33000 Bordeaux, France
| | - Michel Haïssaguerre
- IHU LIRYC, 33600 Pessac, France.,University of Bordeaux, 33000 Bordeaux, France.,Hôpital Haut Lévêque, University Hospital of Bordeaux, 33604 Bordeaux, France
| | - Rutger J Hassink
- Department of Cardiology, University Medical Centre Utrecht, 3584 CX Utrecht, Netherlands
| | | | - Ruben Coronel
- IHU LIRYC, 33600 Pessac, France.,Department of Experimental Cardiology, Amsterdam University Medical Centre, 1105 AZ Amsterdam, Netherlands
| | - Paul G A Volders
- Cardiovascular Research Institute Maastricht, Maastricht University, 6200 MD Maastricht, Netherlands
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19
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van der Waal JG, Meijborg VMF, Belterman CNW, Streekstra GJ, Oostendorp TF, Coronel R. Ex vivo Validation of Noninvasive Epicardial and Endocardial Repolarization Mapping. Front Physiol 2021; 12:737609. [PMID: 34744778 PMCID: PMC8569864 DOI: 10.3389/fphys.2021.737609] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 09/21/2021] [Indexed: 11/17/2022] Open
Abstract
Background: The detection and localization of electrophysiological substrates currently involve invasive cardiac mapping. Electrocardiographic imaging (ECGI) using the equivalent dipole layer (EDL) method allows the noninvasive estimation of endocardial and epicardial activation and repolarization times (AT and RT), but the RT validation is limited to in silico studies. We aimed to assess the temporal and spatial accuracy of the EDL method in reconstructing the RTs from the surface ECG under physiological circumstances and situations with artificially induced increased repolarization heterogeneity. Methods: In four Langendorff-perfused pig hearts, we simultaneously recorded unipolar electrograms from plunge needles and pseudo-ECGs from a volume-conducting container equipped with 61 electrodes. The RTs were computed from the ECGs during atrial and ventricular pacing and compared with those measured from the local unipolar electrograms. Regional RT prolongation (cooling) or shortening (pinacidil) was achieved by selective perfusion of the left anterior descending artery (LAD) region. Results: The differences between the computed and measured RTs were 19.0 ± 17.8 and 18.6 ± 13.7 ms for atrial and ventricular paced beats, respectively. The region of artificially delayed or shortened repolarization was correctly identified, with minimum/maximum RT roughly in the center of the region in three hearts. In one heart, the reconstructed region was shifted by ~2.5 cm. The total absolute difference between the measured and calculated RTs for all analyzed patterns in selectively perfused hearts (n = 5) was 39.6 ± 27.1 ms. Conclusion: The noninvasive ECG repolarization imaging using the EDL method of atrial and ventricular paced beats allows adequate quantitative reconstruction of regions of altered repolarization.
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Affiliation(s)
- Jeanne G van der Waal
- Department of Experimental and Clinical Cardiology, Amsterdam University Medical Centers, Location Academic Medical Center, Amsterdam, Netherlands
| | - Veronique M F Meijborg
- Department of Experimental and Clinical Cardiology, Amsterdam University Medical Centers, Location Academic Medical Center, Amsterdam, Netherlands
| | - Charly N W Belterman
- Department of Experimental and Clinical Cardiology, Amsterdam University Medical Centers, Location Academic Medical Center, Amsterdam, Netherlands
| | - Geert J Streekstra
- Department of Biomedical Engineering and Physics, Amsterdam University Medical Centers, Location Academic Medical Center, Amsterdam, Netherlands
| | - Thom F Oostendorp
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Ruben Coronel
- Department of Experimental and Clinical Cardiology, Amsterdam University Medical Centers, Location Academic Medical Center, Amsterdam, Netherlands.,IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac-Bordeaux, France
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20
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Sung E, Prakosa A, Trayanova NA. Analyzing the Role of Repolarization Gradients in Post-infarct Ventricular Tachycardia Dynamics Using Patient-Specific Computational Heart Models. Front Physiol 2021; 12:740389. [PMID: 34658925 PMCID: PMC8514757 DOI: 10.3389/fphys.2021.740389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 09/06/2021] [Indexed: 11/20/2022] Open
Abstract
Aims: Disease-induced repolarization heterogeneity in infarcted myocardium contributes to VT arrhythmogenesis but how apicobasal and transmural (AB-TM) repolarization gradients additionally affect post-infarct VT dynamics is unknown. The goal of this study is to assess how AB-TM repolarization gradients impact post-infarct VT dynamics using patient-specific heart models. Method: 3D late gadolinium-enhanced cardiac magnetic resonance images were acquired from seven post-infarct patients. Models representing the patient-specific scar and infarct border zone distributions were reconstructed without (baseline) and with repolarization gradients along both the AB-TM axes. AB only and TM only models were created to assess the effects of each ventricular gradient on VT dynamics. VTs were induced in all models via rapid pacing. Results: Ten baseline VTs were induced. VT inducibility in AB-TM models was not significantly different from baseline (p>0.05). Reentry pathways in AB-TM models were different than baseline pathways due to alterations in the location of conduction block (p<0.05). VT exit sites in AB-TM models were different than baseline VT exit sites (p<0.05). VT inducibility of AB only and TM only models were not significantly different than that of baseline (p>0.05) or AB-TM models (p>0.05). Reentry pathways and VT exit sites in AB only and TM only models were different than in baseline (p<0.05). Lastly, repolarization gradients uncovered multiple VT morphologies with different reentrant pathways and exit sites within the same structural, conducting channels. Conclusion: VT inducibility was not impacted by the addition of AB-TM repolarization gradients, but the VT reentrant pathway and exit sites were greatly affected due to modulation of conduction block. Thus, during ablation procedures, physiological and pharmacological factors that impact the ventricular repolarization gradient might need to be considered when targeting the VTs.
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Affiliation(s)
- Eric Sung
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States.,Alliance for Cardiovascular Diagnostic and Treatment Innovation, Johns Hopkins University, Baltimore, MD, United States
| | - Adityo Prakosa
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States.,Alliance for Cardiovascular Diagnostic and Treatment Innovation, Johns Hopkins University, Baltimore, MD, United States
| | - Natalia A Trayanova
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States.,Alliance for Cardiovascular Diagnostic and Treatment Innovation, Johns Hopkins University, Baltimore, MD, United States
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21
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Axelsson KJ, Gransberg L, Lundahl G, Bergfeldt L. Adaptation of ventricular repolarization dispersion during heart rate increase in humans: A roller coaster process. J Electrocardiol 2021; 68:90-100. [PMID: 34411881 DOI: 10.1016/j.jelectrocard.2021.07.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 07/10/2021] [Accepted: 07/24/2021] [Indexed: 10/20/2022]
Abstract
BACKGROUND Regional differences in ventricular activation sequence and action potential duration and morphology result in dispersion in ventricular repolarization (VR). VR dispersion is a key factor in arrhythmogenesis. We studied the adaptation of global VR dispersion in humans during normal and abnormal ventricular activation, and the relation to the QT adaptation (hysteresis). METHODS We measured global VR dispersion as T amplitude, T area, and ventricular gradient (VG), using continuous Frank vectorcardiography, in response to abrupt and sustained atrial (AP) or ventricular pacing (VP) aiming at 120 bpm, in 21 subjects with permanent pacemakers. RESULTS Following pacing start, VR adaptation showed an initially rapid and complex tri-phasic pattern, most pronounced for T amplitude. There were major differences in the patterns of VR dispersion adaptation following abrupt AP vs VP, confirming that the adaptation pattern is activation dependent. In response to AP, an instantaneous decrease in VR dispersion occurred, followed by an increase and then a slow decrease, all at a lower level than baseline. In contrast, following VP there was an immediate increase to ~4× baseline in T amplitude and T area (but not in VG), with a subsequent biphasic adaptation lasting longer during VP than AP. The initial rapid changes occurred within the time for QT adaptation to reach steady-state. CONCLUSIONS Our results corroborate and expand data from animal and invasive human studies, showing similarities of the adaptation pattern on different scales. The initial rapidly changing VR adaptation phase presumably reflects a window of increased vulnerability to arrhythmias.
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Affiliation(s)
- Karl-Jonas Axelsson
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Region Västra Götaland, Department of Cardiology, Sahlgrenska University Hospital, Gothenburg, Sweden.
| | - Lennart Gransberg
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Gunilla Lundahl
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Lennart Bergfeldt
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Region Västra Götaland, Department of Cardiology, Sahlgrenska University Hospital, Gothenburg, Sweden
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22
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Limitations and Pitfalls of Substrate Mapping for Ventricular Tachycardia. JACC Clin Electrophysiol 2021; 7:542-560. [PMID: 33888275 DOI: 10.1016/j.jacep.2021.02.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 02/08/2021] [Accepted: 02/08/2021] [Indexed: 12/11/2022]
Abstract
The fundamental hypothesis of substrate mapping for scar-mediated ventricular tachycardia is that surrogates of the isthmus can be identified and targeted with ablation during sinus rhythm. These surrogates include electrocardiographic indications for electric discontinuity such as fractionation, split, late, and long potentials, also evident as sites displaying activation slowing. However, ablation strategies targeting these surrogates during sinus rhythm have resulted in unacceptably high rates of clinical failures, promoting the idea that a more widespread ablation may be required. High-resolution mapping technologies provide an opportunity to examine the substrate at greater detail; however, their use has not yet translated into improved clinical outcomes. This may be related to ongoing efforts to examine the same surrogates at higher resolution instead of using high-resolution technologies for discovering new and potentially more specific surrogates. This article reviews common limitations and pitfalls of substrate mapping and discusses new opportunities for high-resolution mapping to increase the accuracy of substrate mapping: 1) multielectrode mapping catheters provide an opportunity to rapidly examine the substrate during electrophysiological conditions that more closely simulate ventricular tachycardia by means of activation from different directions and coupling intervals; 2) electrogram annotation methods based on the maximal negative derivative of the extracellular potential or maximal voltage are often inaccurate in nonuniform anisotropic tissue. The use of multielectrode catheters may improve the accuracy of electrogram annotation by using spatiotemporal dispersion of single-beat acquisitions and a localized indifferent reference; and 3) resetting and entrainment remain important methods for studying re-entry for and guiding ablation.
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Gaur N, Qi XY, Benoist D, Bernus O, Coronel R, Nattel S, Vigmond EJ. A computational model of pig ventricular cardiomyocyte electrophysiology and calcium handling: Translation from pig to human electrophysiology. PLoS Comput Biol 2021; 17:e1009137. [PMID: 34191797 PMCID: PMC8277015 DOI: 10.1371/journal.pcbi.1009137] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 07/13/2021] [Accepted: 06/01/2021] [Indexed: 12/01/2022] Open
Abstract
The pig is commonly used as an experimental model of human heart disease, including for the study of mechanisms of arrhythmia. However, there exist differences between human and porcine cellular electrophysiology: The pig action potential (AP) has a deeper phase-1 notch, a longer duration at 50% repolarization, and higher plateau potentials than human. Ionic differences underlying the AP include larger rapid delayed-rectifier and smaller inward-rectifier K+-currents (IKr and IK1 respectively) in humans. AP steady-state rate-dependence and restitution is steeper in pigs. Porcine Ca2+ transients can have two components, unlike human. Although a reliable computational model for human ventricular myocytes exists, one for pigs is lacking. This hampers translation from results obtained in pigs to human myocardium. Here, we developed a computational model of the pig ventricular cardiomyocyte AP using experimental datasets of the relevant ionic currents, Ca2+-handling, AP shape, AP duration restitution, and inducibility of triggered activity and alternans. To properly capture porcine Ca2+ transients, we introduced a two-step process with a faster release in the t-tubular region, followed by a slower diffusion-induced release from a non t-tubular subcellular region. The pig model behavior was compared with that of a human ventricular cardiomyocyte (O’Hara-Rudy) model. The pig, but not the human model, developed early afterdepolarizations (EADs) under block of IK1, while IKr block led to EADs in the human but not in the pig model. At fast rates (pacing cycle length = 400 ms), the human cell model was more susceptible to spontaneous Ca2+ release-mediated delayed afterdepolarizations (DADs) and triggered activity than pig. Fast pacing led to alternans in human but not pig. Developing species-specific models incorporating electrophysiology and Ca2+-handling provides a tool to aid translating antiarrhythmic and arrhythmogenic assessment from the bench to the clinic. The pig is an animal commonly used experimentally to study diseases of the heart, as well as investigate therapies to treat them, such as drugs. However, although similar, pigs differ from humans in certain aspects which may mean experimental results do not always directly translate between species. We propose a mathematical model of porcine electrophysiology which can serve as a tool to understand differences between the species and translate responses. Using new measurements along with values from literature, we built a computer model of porcine cardiac myocyte which replicated voltage and calcium behaviour over a range of pacing frequencies. The pig cell had a two-stage calcium release, unlike humans with a single stage. We predict that pigs and humans differ in the type of potassium current block that makes them most susceptible to cardiac arrhythmia. The model we developed can elucidate important differences between human and pig arrhythmia response.
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Affiliation(s)
- Namit Gaur
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac- Bordeaux, France
- Univ. Bordeaux, IMB, UMR 5251, Talence, France
| | - Xiao-Yan Qi
- Montreal Heart Institute and Université de Montréal, Montreal, Canada
| | - David Benoist
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac- Bordeaux, France
- Univ. Bordeaux, Inserm, CRCTB, U1045, Pessac, France
| | - Olivier Bernus
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac- Bordeaux, France
- Univ. Bordeaux, Inserm, CRCTB, U1045, Pessac, France
| | - Ruben Coronel
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac- Bordeaux, France
- Department of Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands
| | - Stanley Nattel
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac- Bordeaux, France
- Montreal Heart Institute and Université de Montréal, Montreal, Canada
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
| | - Edward J. Vigmond
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac- Bordeaux, France
- Univ. Bordeaux, IMB, UMR 5251, Talence, France
- * E-mail:
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Srinivasan NT, Garcia J, Schilling RJ, Ahsan S, Hunter RJ, Lowe M, Chow AW, Lambiase PD. Dynamic spatial dispersion of repolarization is present in regions critical for ischemic ventricular tachycardia ablation. Heart Rhythm O2 2021; 2:280-289. [PMID: 34337579 PMCID: PMC8322930 DOI: 10.1016/j.hroo.2021.05.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND The presence of dynamic substrate changes may facilitate functional block and reentry in ventricular tachycardia (VT). OBJECTIVE We aimed to study dynamic ventricular repolarization changes in critical regions of the VT circuit during sensed single extrastimulus pacing known as the Sense Protocol (SP). METHODS Twenty patients (aged 67 ± 9 years, 17 male) underwent VT ablation. A bipolar voltage map was obtained during sinus rhythm (SR) and right ventricular SP pacing at 20 ms above ventricular effective refractory period. Ventricular repolarization maps were constructed. Ventricular repolarization time (RT) was calculated from unipolar electrogram T waves, using the Wyatt method, as the dV/dtmax of the unipolar T wave. Entrainment or pace mapping confirmed critical sites for ablation. RESULTS The median global repolarization range (max-min RT per patient) was 166 ms (interquartile range [IQR] 143-181 ms) during SR mapping vs 208 ms (IQR 182-234) during SP mapping (P = .0003 vs intrinsic rhythm). Regions of late potentials (LP) had a longer RT during SP mapping compared to regions without LP (mean 394 ± 40 ms vs 342 ± 25 ms, P < .001). In paired regions of normal myocardium there was no significant spatial dispersion of repolarization (SDR)/10 mm2 during SP mapping vs SR mapping (SDR 11 ± 6 ms vs 10 ± 6 ms, P = .54). SDR/10 mm2 was greater in critical areas of the VT circuit during SP mapping 63 ± 29 ms vs SR mapping 16 ± 9 ms (P < .001). CONCLUSION Ventricular repolarization is prolonged in regions of LP and increases dynamically, resulting in dynamic SDR in critical areas of the VT circuit. These dynamic substrate changes may be an important factor that facilitates VT circuits.
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Affiliation(s)
- Neil T. Srinivasan
- Department of Cardiac Electrophysiology, The Essex Cardiothoracic Centre, Basildon, Essex, United Kingdom
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew’s Hospital, London, United Kingdom
- Institute of Cardiovascular Science, University College London, London, United Kingdom
- Circulatory Health Research Group, Medical Technology Research Centre, School of Medicine, Anglia Ruskin University, Essex, United Kingdom
| | - Jason Garcia
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew’s Hospital, London, United Kingdom
| | - Richard J. Schilling
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew’s Hospital, London, United Kingdom
| | - Syed Ahsan
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew’s Hospital, London, United Kingdom
| | - Ross J. Hunter
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew’s Hospital, London, United Kingdom
| | - Martin Lowe
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew’s Hospital, London, United Kingdom
| | - Anthony W. Chow
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew’s Hospital, London, United Kingdom
| | - Pier D. Lambiase
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew’s Hospital, London, United Kingdom
- Institute of Cardiovascular Science, University College London, London, United Kingdom
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25
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Orini M, Taggart P, Bhuva A, Roberts N, Di Salvo C, Yates M, Badiani S, Van Duijvenboden S, Lloyd G, Smith A, Lambiase PD. Direct in vivo assessment of global and regional mechanoelectric feedback in the intact human heart. Heart Rhythm 2021; 18:1406-1413. [PMID: 33932588 PMCID: PMC8353585 DOI: 10.1016/j.hrthm.2021.04.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 04/23/2021] [Accepted: 04/23/2021] [Indexed: 02/06/2023]
Abstract
Background Inhomogeneity of ventricular contraction is associated with sudden cardiac death, but the underlying mechanisms are unclear. Alterations in cardiac contraction impact electrophysiological parameters through mechanoelectric feedback. This has been shown to promote arrhythmias in experimental studies, but its effect in the in vivo human heart is unclear. Objective The purpose of this study was to quantify the impact of regional myocardial deformation provoked by a sudden increase in ventricular loading (aortic occlusion) on human cardiac electrophysiology. Methods In 10 patients undergoing open heart cardiac surgery, left ventricular (LV) afterload was modified by transient aortic occlusion. Simultaneous assessment of whole-heart electrophysiology and LV deformation was performed using an epicardial sock (240 electrodes) and speckle-tracking transesophageal echocardiography. Parameters were matched to 6 American Heart Association LV model segments. The association between changes in regional myocardial segment length and activation-recovery interval (ARI; a conventional surrogate for action potential duration) was studied using mixed-effect models. Results Increased ventricular loading reduced longitudinal shortening (P = .01) and shortened ARI (P = .02), but changes were heterogeneous between cardiac segments. Increased regional longitudinal shortening was associated with ARI shortening (effect size 0.20 [0.01–0.38] ms/%; P = .04) and increased local ARI dispersion (effect size –0.13 [–0.23 to –0.03] ms/%; P = .04). At the whole organ level, increased mechanical dispersion translated into increased dispersion of repolarization (correlation coefficient r = 0.81; P = .01). Conclusion Mechanoelectric feedback can establish a potentially proarrhythmic substrate in the human heart and should be considered to advance our understanding and prevention of cardiac arrhythmias.
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Affiliation(s)
- Michele Orini
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom; Institute of Cardiovascular Science, University College London, London, United Kingdom
| | - Peter Taggart
- Institute of Cardiovascular Science, University College London, London, United Kingdom.
| | - Anish Bhuva
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom; Institute of Cardiovascular Science, University College London, London, United Kingdom
| | - Neil Roberts
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | - Carmelo Di Salvo
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | - Martin Yates
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | - Sveeta Badiani
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | | | - Guy Lloyd
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | - Andrew Smith
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | - Pier D Lambiase
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom; Institute of Cardiovascular Science, University College London, London, United Kingdom
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26
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Affiliation(s)
- Yoram Rudy
- Cardiac Bioelectricity and Arrhythmia Center Washington University in St. Louis MO
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27
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Bear LR, Cluitmans M, Abell E, Rogier J, Labrousse L, Cheng LK, LeGrice I, Lever N, Sands GB, Smaill B, Haïssaguerre M, Bernus O, Coronel R, Dubois R. Electrocardiographic Imaging of Repolarization Abnormalities. J Am Heart Assoc 2021; 10:e020153. [PMID: 33880931 PMCID: PMC8200734 DOI: 10.1161/jaha.120.020153] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Background Dispersion and gradients in repolarization have been associated with life‐threatening arrhythmias, but are difficult to quantify precisely from surface electrocardiography. The objective of this study was to evaluate electrocardiographic imaging (ECGI) to noninvasively detect repolarization‐based abnormalities. Methods and Results Ex vivo data were obtained from Langendorff‐perfused pig hearts (n=8) and a human donor heart. Unipolar electrograms were recorded simultaneously during sinus rhythm from an epicardial sock and the torso‐shaped tank within which the heart was suspended. Regional repolarization heterogeneities were introduced through perfusion of dofetilide and pinacidil into separate perfusion beds. In vivo data included torso and epicardial potentials recorded simultaneously in anesthetized, closed‐chest pigs (n=5), during sinus rhythm, and ventricular pacing. For both data sets, ECGI accurately reconstructed T‐wave electrogram morphologies when compared with those recorded by the sock (ex vivo: correlation coefficient, 0.85 [0.52–0.96], in vivo: correlation coefficient, 0.86 [0.52–0.96]) and repolarization time maps (ex‐vivo: correlation coefficient, 0.73 [0.63–0.83], in vivo: correlation coefficient, 0.76 [0.67–0.82]). ECGI‐reconstructed repolarization time distributions were strongly correlated to those measured by the sock (both data sets, R2 ≥0.92). Although the position of the gradient was slightly shifted by 8.3 (0–13.9) mm, the mean, max, and SD between ECGI and recorded gradient values were highly correlated (R2=0.87, 0.75, and 0.86 respectively). There was no significant difference in ECGI accuracy between ex vivo and in vivo data. Conclusions ECGI reliably and accurately maps potentially critical repolarization abnormalities. This noninvasive approach allows imaging and quantifying individual parameters of abnormal repolarization‐based substrates in patients with arrhythmogenesis, to improve diagnosis and risk stratification.
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Affiliation(s)
- Laura R Bear
- IHU-LIRYCFondation Bordeaux Université Pessac France.,CRCTB U1045 Université de Bordeaux Bordeaux France.,Inserm U1045 CRCTB Pessac France
| | - Matthijs Cluitmans
- CARIM School for Cardiovascular Diseases Maastricht UMC Maastricht Netherlands
| | - Emma Abell
- IHU-LIRYCFondation Bordeaux Université Pessac France.,CRCTB U1045 Université de Bordeaux Bordeaux France.,Inserm U1045 CRCTB Pessac France
| | | | - Louis Labrousse
- IHU-LIRYCFondation Bordeaux Université Pessac France.,Department of Cardiac Surgery CHU Pessac France
| | - Leo K Cheng
- Auckland Bioengineering Institute University of Auckland Auckland New Zealand
| | - Ian LeGrice
- Auckland Bioengineering Institute University of Auckland Auckland New Zealand
| | - Nigel Lever
- Auckland Bioengineering Institute University of Auckland Auckland New Zealand
| | - Gregory B Sands
- Auckland Bioengineering Institute University of Auckland Auckland New Zealand
| | - Bruce Smaill
- Auckland Bioengineering Institute University of Auckland Auckland New Zealand
| | - Michel Haïssaguerre
- IHU-LIRYCFondation Bordeaux Université Pessac France.,CRCTB U1045 Université de Bordeaux Bordeaux France.,Inserm U1045 CRCTB Pessac France.,Department of Cardiac Electrophysiology and Stimulation Bordeaux University Hospital (CHU) Pessac France
| | - Olivier Bernus
- IHU-LIRYCFondation Bordeaux Université Pessac France.,CRCTB U1045 Université de Bordeaux Bordeaux France.,Inserm U1045 CRCTB Pessac France
| | - Ruben Coronel
- IHU-LIRYCFondation Bordeaux Université Pessac France.,Department of Experimental Cardiology Academic Medical Center Amsterdam the Netherlands
| | - Rémi Dubois
- IHU-LIRYCFondation Bordeaux Université Pessac France.,CRCTB U1045 Université de Bordeaux Bordeaux France.,Inserm U1045 CRCTB Pessac France
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28
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Langfield P, Feng Y, Bear LR, Duchateau J, Sebastian R, Abell E, Dubois R, Labrousse L, Rogier J, Hocini M, Haissaguerre M, Vigmond E. A novel method to correct repolarization time estimation from unipolar electrograms distorted by standard filtering. Med Image Anal 2021; 72:102075. [PMID: 34020081 DOI: 10.1016/j.media.2021.102075] [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: 05/21/2020] [Revised: 03/30/2021] [Accepted: 04/02/2021] [Indexed: 11/30/2022]
Abstract
Reliable patient-specific ventricular repolarization times (RTs) can identify regions of functional block or afterdepolarizations, indicating arrhythmogenic cardiac tissue and the risk of sudden cardiac death. Unipolar electrograms (UEs) record electric potentials, and the Wyatt method has been shown to be accurate for estimating RT from a UE. High-pass filtering is an important step in processing UEs, however, it is known to distort the T-wave phase of the UE, which may compromise the accuracy of the Wyatt method. The aim of this study was to examine the effects of high-pass filtering, and improve RT estimates derived from filtered UEs. We first generated a comprehensive set of UEs, corresponding to early and late activation and repolarization, that were then high-pass filtered with settings that mimicked the CARTO filter. We trained a deep neural network (DNN) to output a probabilistic estimation of RT and a measure of confidence, using the filtered synthetic UEs and their true RTs. Unfiltered ex-vivo human UEs were also filtered and the trained DNN used to estimate RT. Even a modest 2 Hz high-pass filter imposes a significant error on RT estimation using the Wyatt method. The DNN outperformed the Wyatt method in 62.75% of cases, and produced a significantly lower absolute error (p=8.99E-13), with a median of 16.91 ms, on 102 ex-vivo UEs. We also applied the DNN to patient UEs from CARTO, from which an RT map was computed. In conclusion, DNNs trained on synthetic UEs improve the RT estimation from filtered UEs, which leads to more reliable repolarization maps that help to identify patient-specific repolarization abnormalities.
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Affiliation(s)
- Peter Langfield
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac-Bordeaux, France; Univ. Bordeaux, IMB UMR 5251, Talence F-33400, France.
| | - Yingjing Feng
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac-Bordeaux, France; Univ. Bordeaux, IMB UMR 5251, Talence F-33400, France.
| | - Laura R Bear
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac-Bordeaux, France
| | - Josselin Duchateau
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac-Bordeaux, France; Bordeaux University Hospital (CHU), Cardiac Electrophysiology and Cardiac Stimulation Team, Pessac, France
| | - Rafael Sebastian
- CoMMLab, Dept. Computer Sciences, Universitat de Valencia, Valencia, Spain
| | - Emma Abell
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac-Bordeaux, France
| | - Remi Dubois
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac-Bordeaux, France
| | - Louis Labrousse
- Bordeaux University Hospital (CHU), Cardiac Electrophysiology and Cardiac Stimulation Team, Pessac, France
| | - Julien Rogier
- Bordeaux University Hospital (CHU), Cardiac Electrophysiology and Cardiac Stimulation Team, Pessac, France
| | - Meleze Hocini
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac-Bordeaux, France; Bordeaux University Hospital (CHU), Cardiac Electrophysiology and Cardiac Stimulation Team, Pessac, France
| | - Michel Haissaguerre
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac-Bordeaux, France; Bordeaux University Hospital (CHU), Cardiac Electrophysiology and Cardiac Stimulation Team, Pessac, France
| | - Edward Vigmond
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac-Bordeaux, France; Univ. Bordeaux, IMB UMR 5251, Talence F-33400, France
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29
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Song ZL, Liu Y, Liu X, Qin M. Absence of Rgs5 Influences the Spatial and Temporal Fluctuation of Cardiac Repolarization in Mice. Front Physiol 2021; 12:622084. [PMID: 33815137 PMCID: PMC8012757 DOI: 10.3389/fphys.2021.622084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 02/22/2021] [Indexed: 11/25/2022] Open
Abstract
Aims This study investigated the contribution of the regulator of G-protein signaling 5 (Rgs5) knockout to the alteration of the action potential duration (APD) restitution and repolarizing dispersion in ventricle. Methods and Results The effects of Rgs5–/– were investigated by QT variance (QTv) and heart rate variability analysis of Rgs5–/– mice. Monophasic action potential analysis was investigated in isolated Rgs5–/– heart. Rgs5–/– did not promote ventricular remodeling. The 24-h QTv and QT variability index (QTVI) of the Rgs5–/– mice were higher than those of wild-type (WT) mice (P < 0.01). In WT mice, a positive correlation was found between QTv and the standard deviation of all NN intervals (r = 0.62; P < 0.01), but not in Rgs5–/– mice (R = 0.01; P > 0.05). The absence of Rgs5 resulted in a significant prolongation of effective refractory period and APD in isolated ventricle. In addition, compared with WT mice, the knockout of Rgs5 significantly deepened the slope of the APD recovery curve at all 10 sites of the heart (P < 0.01) and increased the spatial dispersions of Smax (COV-Smax) (WT: 0.28 ± 0.03, Rgs5–/–: 0.53 ± 0.08, P < 0.01). Compared with WT heart, Rgs5–/– increased the induced S1–S2 interval at all sites of heart and widened the window of vulnerability of ventricular tachyarrhythmia (P < 0.05). Conclusion Our findings indicate that Rgs5–/– is an important regulator of ventricular tachyarrhythmia in mice by prolonging ventricular repolarization and increasing spatial dispersion in ventricle.
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Affiliation(s)
- Zi-Liang Song
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Yang Liu
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Xu Liu
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Mu Qin
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
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30
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Campos FO, Orini M, Arnold R, Whitaker J, O'Neill M, Razavi R, Plank G, Hanson B, Porter B, Rinaldi CA, Gill J, Lambiase PD, Taggart P, Bishop MJ. Assessing the ability of substrate mapping techniques to guide ventricular tachycardia ablation using computational modelling. Comput Biol Med 2021; 130:104214. [PMID: 33476992 DOI: 10.1016/j.compbiomed.2021.104214] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 01/05/2021] [Accepted: 01/05/2021] [Indexed: 01/19/2023]
Abstract
BACKGROUND Identification of targets for ablation of post-infarction ventricular tachycardias (VTs) remains challenging, often requiring arrhythmia induction to delineate the reentrant circuit. This carries a risk for the patient and may not be feasible. Substrate mapping has emerged as a safer strategy to uncover arrhythmogenic regions. However, VT recurrence remains common. GOAL To use computer simulations to assess the ability of different substrate mapping approaches to identify VT exit sites. METHODS A 3D computational model of the porcine post-infarction heart was constructed to simulate VT and paced rhythm. Electroanatomical maps were constructed based on endocardial electrogram features and the reentry vulnerability index (RVI - a metric combining activation (AT) and repolarization timings to identify tissue susceptibility to reentry). Since scar transmurality in our model was not homogeneous, parameters derived from all signals (including dense scar regions) were used in the analysis. Potential ablation targets obtained from each electroanatomical map during pacing were compared to the exit site detected during VT mapping. RESULTS Simulation data showed that voltage cut-offs applied to bipolar electrograms could delineate the scar, but not the VT circuit. Electrogram fractionation had the highest correlation with scar transmurality. The RVI identified regions closest to VT exit site but was outperformed by AT gradients combined with voltage cut-offs. The performance of all metrics was affected by pacing location. CONCLUSIONS Substrate mapping could provide information about the infarct, but the directional dependency on activation should be considered. Activation-repolarization metrics have utility in safely identifying VT targets, even with non-transmural scars.
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Affiliation(s)
- Fernando O Campos
- School of Biomedical Engineering and Imaging Sciences, Rayne Institute, 4th Floor, Lambeth Wing, St. Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, United Kingdom.
| | - Michele Orini
- Institute of Cardiovascular Science, University College London, London, United Kingdom; Electrophysiology Department, Barts Heart Centre, St Bartholomew's Hospital, London, United Kingdom
| | - Robert Arnold
- Gottfried Schatz Research Center (for Cell Signaling, Metabolism and Aging), Division of Biophysics, Graz, Austria
| | - John Whitaker
- School of Biomedical Engineering and Imaging Sciences, Rayne Institute, 4th Floor, Lambeth Wing, St. Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, United Kingdom
| | - Mark O'Neill
- School of Biomedical Engineering and Imaging Sciences, Rayne Institute, 4th Floor, Lambeth Wing, St. Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, United Kingdom
| | - Reza Razavi
- School of Biomedical Engineering and Imaging Sciences, Rayne Institute, 4th Floor, Lambeth Wing, St. Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, United Kingdom
| | - Gernot Plank
- Gottfried Schatz Research Center (for Cell Signaling, Metabolism and Aging), Division of Biophysics, Graz, Austria
| | - Ben Hanson
- Department of Mechanical Engineering, University College London, London, United Kingdom
| | - Bradley Porter
- School of Biomedical Engineering and Imaging Sciences, Rayne Institute, 4th Floor, Lambeth Wing, St. Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, United Kingdom; Department of Cardiology, Guys and St Thomas' NHS Trust, London, United Kingdom
| | | | - Jaswinder Gill
- School of Biomedical Engineering and Imaging Sciences, Rayne Institute, 4th Floor, Lambeth Wing, St. Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, United Kingdom; Department of Cardiology, Guys and St Thomas' NHS Trust, London, United Kingdom
| | - Pier D Lambiase
- Institute of Cardiovascular Science, University College London, London, United Kingdom; Electrophysiology Department, Barts Heart Centre, St Bartholomew's Hospital, London, United Kingdom
| | - Peter Taggart
- Institute of Cardiovascular Science, University College London, London, United Kingdom; Electrophysiology Department, Barts Heart Centre, St Bartholomew's Hospital, London, United Kingdom
| | - Martin J Bishop
- School of Biomedical Engineering and Imaging Sciences, Rayne Institute, 4th Floor, Lambeth Wing, St. Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, United Kingdom
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31
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Varró A, Tomek J, Nagy N, Virág L, Passini E, Rodriguez B, Baczkó I. Cardiac transmembrane ion channels and action potentials: cellular physiology and arrhythmogenic behavior. Physiol Rev 2020; 101:1083-1176. [PMID: 33118864 DOI: 10.1152/physrev.00024.2019] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Cardiac arrhythmias are among the leading causes of mortality. They often arise from alterations in the electrophysiological properties of cardiac cells and their underlying ionic mechanisms. It is therefore critical to further unravel the pathophysiology of the ionic basis of human cardiac electrophysiology in health and disease. In the first part of this review, current knowledge on the differences in ion channel expression and properties of the ionic processes that determine the morphology and properties of cardiac action potentials and calcium dynamics from cardiomyocytes in different regions of the heart are described. Then the cellular mechanisms promoting arrhythmias in congenital or acquired conditions of ion channel function (electrical remodeling) are discussed. The focus is on human-relevant findings obtained with clinical, experimental, and computational studies, given that interspecies differences make the extrapolation from animal experiments to human clinical settings difficult. Deepening the understanding of the diverse pathophysiology of human cellular electrophysiology will help in developing novel and effective antiarrhythmic strategies for specific subpopulations and disease conditions.
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Affiliation(s)
- András Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - Jakub Tomek
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Norbert Nagy
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - László Virág
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Elisa Passini
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Blanca Rodriguez
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
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Rivaud MR, Bayer JD, Cluitmans M, van der Waal J, Bear LR, Boukens BJ, Belterman C, Gottlieb L, Vaillant F, Abell E, Dubois R, Meijborg VMF, Coronel R. Critical repolarization gradients determine the induction of reentry-based torsades de pointes arrhythmia in models of long QT syndrome. Heart Rhythm 2020; 18:278-287. [PMID: 33031961 DOI: 10.1016/j.hrthm.2020.09.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 09/21/2020] [Accepted: 09/26/2020] [Indexed: 01/08/2023]
Abstract
BACKGROUND Torsades de pointes arrhythmia is a potentially lethal polymorphic ventricular tachyarrhythmia (pVT) in the setting of long QT syndrome. Arrhythmia susceptibility is influenced by risk factors modifying repolarization. OBJECTIVE The purpose of this article was to characterize repolarization duration and heterogeneity in relation to pVT inducibility and maintenance. METHODS Sotalol was infused regionally or globally in isolated Langendorff blood-perfused pig hearts (N = 7) to create repolarization time (RT) heterogeneities. Programmed stimulation and epicardial activation and repolarization mapping were performed. The role of RT (heterogeneities) was studied in more detail using a computer model of the human heart. RESULTS pVTs (n = 11) were inducible at a critical combination of RT and RT heterogeneities. The pVT cycle lengths were similar in the short and long RT regions. Short-lasting pVTs were maintained by focal activity while longer-lasting pVTs by reentry wandering along the interface between the 2 regions. Local restitution curves from the long and short RT regions crossed. This was associated with T-wave inversion at coupling intervals at either side of the crossing point. These experimental observations were confirmed by the computer simulations. CONCLUSION pVTs are inducible within a critical range of RT and RT heterogeneities and are maintained by reentry wandering along the repolarization gradient. Double potentials localize at the core of the reentrant circuit and reflect phase singularities. RT gradient and T waves invert with short-coupled premature beats in the long RT region as a result of the crossing of the restitution curves allowing reentry initiation.
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Affiliation(s)
- Mathilde R Rivaud
- Department of Clinical and Experimental Cardiology, Amsterdam UMC, AMC, Amsterdam, The Netherlands.
| | - Jason D Bayer
- Electrophysiology and Heart Modeling Institute, IHU Liryc, Fondation Bordeaux Université, Pessac-Bordeaux, France; Institut de Mathématiques de Bordeaux, UMR5251, Centre National De La Recherche Scientifique, Bordeaux, France
| | - Matthijs Cluitmans
- Department of Clinical and Experimental Cardiology, Amsterdam UMC, AMC, Amsterdam, The Netherlands; CARIM School for Cardiovascular Disease, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Jeanne van der Waal
- Department of Clinical and Experimental Cardiology, Amsterdam UMC, AMC, Amsterdam, The Netherlands
| | - Laura R Bear
- Electrophysiology and Heart Modeling Institute, IHU Liryc, Fondation Bordeaux Université, Pessac-Bordeaux, France
| | - Bastiaan J Boukens
- Department of Clinical and Experimental Cardiology, Amsterdam UMC, AMC, Amsterdam, The Netherlands; Department of Medical Biology, Amsterdam UMC, AMC, Amsterdam, The Netherlands
| | - Charly Belterman
- Electrophysiology and Heart Modeling Institute, IHU Liryc, Fondation Bordeaux Université, Pessac-Bordeaux, France
| | - Lisa Gottlieb
- Electrophysiology and Heart Modeling Institute, IHU Liryc, Fondation Bordeaux Université, Pessac-Bordeaux, France
| | - Fanny Vaillant
- Electrophysiology and Heart Modeling Institute, IHU Liryc, Fondation Bordeaux Université, Pessac-Bordeaux, France
| | - Emma Abell
- Electrophysiology and Heart Modeling Institute, IHU Liryc, Fondation Bordeaux Université, Pessac-Bordeaux, France
| | - Remi Dubois
- Electrophysiology and Heart Modeling Institute, IHU Liryc, Fondation Bordeaux Université, Pessac-Bordeaux, France
| | - Veronique M F Meijborg
- Department of Clinical and Experimental Cardiology, Amsterdam UMC, AMC, Amsterdam, The Netherlands
| | - Ruben Coronel
- Department of Clinical and Experimental Cardiology, Amsterdam UMC, AMC, Amsterdam, The Netherlands; Electrophysiology and Heart Modeling Institute, IHU Liryc, Fondation Bordeaux Université, Pessac-Bordeaux, France
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Pham VT, Lin C, Tran TT, M Su MY, Lin YK, Nien CT, I Tseng WY, Lin JL, Lo MT, Lin LY. Predicting ventricular tachyarrhythmia in patients with systolic heart failure based on texture features of the gray zone from contrast-enhanced magnetic resonance imaging. J Cardiol 2020; 76:601-609. [PMID: 32675026 DOI: 10.1016/j.jjcc.2020.06.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 06/11/2020] [Accepted: 06/15/2020] [Indexed: 12/22/2022]
Abstract
BACKGROUND Previous research showed that gray zone detected by late gadolinium enhancement cardiovascular magnetic resonance (LGE-CMR) imaging could help identify high-risk patients. In this study, we investigated whether LGE-CMR gray zone heterogeneity measured by image texture features could predict cardiovascular events in patients with heart failure (HF). METHOD This is a retrospective cohort study. Patients with systolic HF undergoing CMR imaging were enrolled. Cine and LGE images were analyzed to derive left ventricular (LV) function and scar characteristics. Entropy and uniformity of gray zones were derived by texture analysis. RESULTS A total of 82 systolic HF patients were enrolled. After a median 1021 (25%-75% quartiles, 205-2066) days of follow-up, the entropy (0.60 ± 0.260 vs. 0.87 ± 0.28, p = 0.013) was significantly increased while the uniformity (0.68 ± 0.14 vs. 0.53±0.15, p = 0.016) was significantly decreased in patients with ventricular tachycardia or ventricular fibrillation (VT/VF). The percentage of core scar (21.9 ± 10.6 vs. 30.6 ± 10.4, p = 0.029) was higher in cardiac mortality group than survival group while the uniformity (0.55 ± 0.17 vs. 0.67 ± 0.14, p = 0.018) was lower in cardiac mortality group than survival group. A multivariate Cox regression model showed that higher percentage of gray zone area (HR = 8.805, 1.620-47.84, p = 0.045), higher entropy (>0.85) (HR = 1.391, 1.092-1.772, p = 0.024) and lower uniformity (≦0.54) (HR = 0.535, 0.340-0.842, p = 0.022) were associated with VT/VF attacks. Also, higher percentage of gray zone area (HR = 5.716, 1.379-23.68, p = 0.017), core scar zone (HR = 1.939, 1.056-3.561, p = 0.025), entropy (>0.85) (HR = 1.434, 1.076-1.911, p = 0.008) and lower uniformity (≦0.54) (HR = 0.513, 0.296-0.888, p = 0.009) were associated with cardiac mortality during follow-up. CONCLUSIONS Gray zone heterogeneity by texture analysis method could provide additional prognostic value to traditional LGE-CMR substrate analysis method.
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Affiliation(s)
- Van-Truong Pham
- School of Electrical Engineering, Hanoi University of Science and Technology, Hanoi, Vietnam; Department of Biomedical Sciences and Engineering, National Central University, Taoyuan, Taiwan
| | - Chen Lin
- Department of Biomedical Sciences and Engineering, National Central University, Taoyuan, Taiwan; Department of Internal Medicine, National Taiwan University College of Medicine and Hospital, Taipei, Taiwan.
| | - Thi-Thao Tran
- School of Electrical Engineering, Hanoi University of Science and Technology, Hanoi, Vietnam; Department of Biomedical Sciences and Engineering, National Central University, Taoyuan, Taiwan
| | - Mao-Yuan M Su
- Department of Medical Imaging, National Taiwan University Hospital, Taipei, Taiwan
| | - Ying-Kuang Lin
- Department of Biomedical Sciences and Engineering, National Central University, Taoyuan, Taiwan; Department of Medicine, Taiwan Landseed Hospital, Taoyuan, Taiwan
| | - Chun-Tung Nien
- Department of Biomedical Sciences and Engineering, National Central University, Taoyuan, Taiwan; Department of Medicine, Taiwan Landseed Hospital, Taoyuan, Taiwan
| | - Wen-Yih I Tseng
- Department of Medical Imaging, National Taiwan University Hospital, Taipei, Taiwan; Center for Optoelectronic Biomedicine, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Jiunn-Lee Lin
- Department of Internal Medicine, National Taiwan University College of Medicine and Hospital, Taipei, Taiwan
| | - Men-Tzung Lo
- Department of Biomedical Sciences and Engineering, National Central University, Taoyuan, Taiwan
| | - Lian-Yu Lin
- Department of Internal Medicine, National Taiwan University College of Medicine and Hospital, Taipei, Taiwan.
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van der Waal J, Meijborg V, Schuler S, Coronel R, Oostendorp T. In silico validation of electrocardiographic imaging to reconstruct the endocardial and epicardial repolarization pattern using the equivalent dipole layer source model. Med Biol Eng Comput 2020; 58:1739-1749. [PMID: 32474796 PMCID: PMC7340677 DOI: 10.1007/s11517-020-02203-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 05/22/2020] [Indexed: 02/07/2023]
Abstract
The solution of the inverse problem of electrocardiology allows the reconstruction of the spatial distribution of the electrical activity of the heart from the body surface electrocardiogram (electrocardiographic imaging, ECGI). ECGI using the equivalent dipole layer (EDL) model has shown to be accurate for cardiac activation times. However, validation of this method to determine repolarization times is lacking. In the present study, we determined the accuracy of the EDL model in reconstructing cardiac repolarization times, and assessed the robustness of the method under less ideal conditions (addition of noise and errors in tissue conductivity). A monodomain model was used to determine the transmembrane potentials in three different excitation-repolarization patterns (sinus beat and ventricular ectopic beats) as the gold standard. These were used to calculate the body surface ECGs using a finite element model. The resulting body surface electrograms (ECGs) were used as input for the EDL-based inverse reconstruction of repolarization times. The reconstructed repolarization times correlated well (COR > 0.85) with the gold standard, with almost no decrease in correlation after adding errors in tissue conductivity of the model or noise to the body surface ECG. Therefore, ECGI using the EDL model allows adequate reconstruction of cardiac repolarization times. Graphical abstract Validation of electrocardiographic imaging for repolarization using forward calculated body surface ECGs from simulated activation-repolarization sequences.
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Affiliation(s)
- Jeanne van der Waal
- Department of Clinical and Experimental Cardiology, Amsterdam University Medical Centers, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands.
| | - Veronique Meijborg
- Department of Clinical and Experimental Cardiology, Amsterdam University Medical Centers, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands
| | - Steffen Schuler
- Institute of Biomedical Engineering, Karlsruhe Institute of Technology, Fritz-Haber-Weg 1, 76131, Karlsruhe, Germany
| | - Ruben Coronel
- Department of Clinical and Experimental Cardiology, Amsterdam University Medical Centers, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands
| | - Thom Oostendorp
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Kapittelweg 29, 6525, Nijmegen, The Netherlands
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Hoogendijk MG, Géczy T, Yap SC, Szili-Torok T. Pathophysiological Mechanisms of Premature Ventricular Complexes. Front Physiol 2020; 11:406. [PMID: 32528299 PMCID: PMC7247859 DOI: 10.3389/fphys.2020.00406] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 04/06/2020] [Indexed: 11/29/2022] Open
Abstract
Premature ventricular complexes (PVCs) are the most common ventricular arrhythmia. Despite the high prevalence, the cause of PVCs remains elusive in most patients. A better understanding of the underlying pathophysiological mechanism may help to steer future research. This review aims to provide an overview of the potential pathophysiological mechanisms of PVCs and their differentiation.
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Affiliation(s)
- Mark G Hoogendijk
- Department of Cardiology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Tamás Géczy
- Department of Cardiology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Sing-Chien Yap
- Department of Cardiology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Tamas Szili-Torok
- Department of Cardiology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
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Anter E, Neuzil P, Reddy VY, Petru J, Park KM, Sroubek J, Leshem E, Zimetbaum PJ, Buxton AE, Kleber AG, Shen C, Wit AL. Ablation of Reentry-Vulnerable Zones Determined by Left Ventricular Activation From Multiple Directions: A Novel Approach for Ventricular Tachycardia Ablation: A Multicenter Study (PHYSIO-VT). Circ Arrhythm Electrophysiol 2020; 13:e008625. [PMID: 32372657 DOI: 10.1161/circep.120.008625] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND The optimal method to identify the arrhythmogenic substrate of scar-related ventricular tachycardia (VT) is unknown. Sites of activation slowing during sinus rhythm (SR) often colocalize with the VT circuit. However, the utility and limitations of such approach for guiding ablation are unknown. METHODS We conducted a multicenter study in patients with infarct-related VT. The left ventricular (LV) was mapped during activation from 3 directions: SR (or atrial pacing), right ventricular, and LV pacing at 600 ms. Ablation was applied selectively to the cumulative area of slow activation, defined as the sum of all regions with activation times of ≥40 ms per 10 mm. Hemodynamically tolerated VTs were mapped with activation or entrainment. The primary outcome was a composite of appropriate implanted cardioverter-defibrillator therapies and cardiovascular death. RESULTS In 85 patients, the LV was mapped during activation from 2.4±0.6 directions. The direction of LV activation influenced the location and magnitude of activation slowing. The spatial overlap of activation slowing between SR and right ventricular pacing was 84.2±7.1%, between SR and LV pacing was 61.4±8.8%, and between right ventricular and LV pacing was 71.3±9.6% (P<0.05 between all comparisons). Mapping during SR identified only 66.2±8.2% of the entire area of activation slowing and 58% critical isthmus sites. Activation from other directions by right ventricular and LV stimulation unmasked an additional 33% of slowly conducting zones and 25% critical isthmus sites. The area of maximal activation slowing often corresponded to the site where the wavefront first interacted with the infarct. During a follow-up period of 3.6 years, the primary end point occurred in 14 out of 85 (16.5%) patients. CONCLUSIONS The spatial distribution of activation slowing is dependent on the direction of LV activation with the area of maximal slowing corresponding to the site where the wavefront first interacts with the infarct. This data may have implications for VT substrate mapping strategies.
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Affiliation(s)
- Elad Anter
- Cardiac Electrophysiology Section, Department of Cardiovascular Medicine, Cleveland Clinic, OH (E.A.)
| | - Petr Neuzil
- Department of Cardiology, Homolka Hospital, Prague, Czech Republic (P.N., V.Y.R., J.P.)
| | - Vivek Y Reddy
- Department of Cardiology, Homolka Hospital, Prague, Czech Republic (P.N., V.Y.R., J.P.).,Helmsley Electrophysiology Center, Division of Cardiology, Icahn School of Medicine at Mount Sinai, New York, NY (V.Y.R.)
| | - Jan Petru
- Department of Cardiology, Homolka Hospital, Prague, Czech Republic (P.N., V.Y.R., J.P.)
| | - Kyoung-Min Park
- Division of Cardiology, Department of Internal Medicine, Samsung Medical Center, Sungkyunkwan university, Seoul, Republic of Korea (K.-M.P.)
| | - Jakub Sroubek
- Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Department of Medicine (J.S., E.L., P.J.Z., A.E.B., A.G.K.), Beth Israel Deaconess Medical Center, Harvard Medical School
| | - Eran Leshem
- Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Department of Medicine (J.S., E.L., P.J.Z., A.E.B., A.G.K.), Beth Israel Deaconess Medical Center, Harvard Medical School
| | - Peter J Zimetbaum
- Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Department of Medicine (J.S., E.L., P.J.Z., A.E.B., A.G.K.), Beth Israel Deaconess Medical Center, Harvard Medical School
| | - Alfred E Buxton
- Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Department of Medicine (J.S., E.L., P.J.Z., A.E.B., A.G.K.), Beth Israel Deaconess Medical Center, Harvard Medical School
| | - Andre G Kleber
- Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Department of Medicine (J.S., E.L., P.J.Z., A.E.B., A.G.K.), Beth Israel Deaconess Medical Center, Harvard Medical School
| | - Changyu Shen
- Richard A. and Susan F. Smith Center for Cardiovascular Outcomes Research, Division of Cardiovascular Medicine (C.S.), Beth Israel Deaconess Medical Center, Harvard Medical School
| | - Andrew L Wit
- Department of Pharmacology, College of Physicians and Surgeons of Columbia University, New York, NY (A.L.W.)
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Arteyeva NV, Azarov JE. ECG markers of local but not global increase in dispersion of ventricular repolarization (simulation study). J Electrocardiol 2020; 60:54-59. [PMID: 32268231 DOI: 10.1016/j.jelectrocard.2020.03.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 03/13/2020] [Accepted: 03/20/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND An increase in local dispersion of repolarization (DOR) may contribute more to arrhythmogenesis as compared to changes of global DOR. The aim of this simulation study was to find ECG markers of local increase in DOR in conditions where global DOR remains normal. METHODS In the framework of van Oosterom and Oostendorp ECGSIM model, the local DOR was increased in 10 different ventricular locations by (1) action potential duration (APD) shortening/lengthening both on epi- and endocardium, (2) epicardial APD shortening, and (3) endocardial APD shortening. The simulation cases where the increase in local DOR was accompanied by increase in global DOR were excluded from consideration. T-wave parameters were analyzed in the simulated precordial and anatomically ordered limb leads. RESULTS The increase in local DOR resulted in increased lead-to‑lead differences in Tpeak and Tend instants in 28 out of 32 simulated scenarios, and in an increased dispersion of Tpeak-Tend interval throughout 12 standard leads in 8 out of 32 simulated scenarios. In all simulations, the global DOR measured as a difference between earliest and latest repolarization times and standard APD deviation was the same. CONCLUSIONS The local increase in DOR was expressed in increased lead-to‑lead differences in Tpeak and Tend instants between adjacent anatomically ordered standard leads (aVL, I, aVR(-), II, aVF, III, and V1-V6), even if global DOR, Tpeak-Tend interval and Tpeak-Tend dispersion were within a normal range.
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Affiliation(s)
- Natalia V Arteyeva
- Department of Cardiac Physiology, Institute of Physiology, Komi Science Center, Ural Branch, Russian Academy of Sciences, 50, Pervomayskaya st., Syktyvkar 167982, Russia.
| | - Jan E Azarov
- Department of Cardiac Physiology, Institute of Physiology, Komi Science Center, Ural Branch, Russian Academy of Sciences, 50, Pervomayskaya st., Syktyvkar 167982, Russia; Department of Physiology, Medical Institute of Pitirim Sorokin, Syktyvkar State University, 11, Babushkin st., Syktyvkar 167000, Russia
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Evaluation of the reentry vulnerability index to predict ventricular tachycardia circuits using high-density contact mapping. Heart Rhythm 2019; 17:576-583. [PMID: 31751771 PMCID: PMC7105818 DOI: 10.1016/j.hrthm.2019.11.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Indexed: 11/24/2022]
Abstract
Background Identifying arrhythmogenic sites to improve ventricular tachycardia (VT) ablation outcomes remains unresolved. The reentry vulnerability index (RVI) combines activation and repolarization timings to identify sites critical for reentrant arrhythmia initiation without inducing VT. Objective The purpose of this study was to provide the first assessment of RVI’s capability to identify VT sites of origin using high-density contact mapping and comparison with other activation-repolarization markers of functional substrate. Methods Eighteen VT ablation patients (16 male; 72% ischemic) were studied. Unipolar electrograms were recorded during ventricular pacing and analyzed offline. Activation time (AT), activation–recovery interval (ARI), and repolarization time (RT) were measured. Vulnerability to reentry was mapped based on RVI and spatial distribution of AT, ARI, and RT. The distance from sites identified as vulnerable to reentry to the VT site of origin was measured, with distances <10 mm and >20 mm indicating accurate and inaccurate localization, respectively. Results The origins of 18 VTs (6 entrainment, 12 pace-mapping) were identified. RVI maps included 1012 (408–2098) (median, 1st–3rd quartiles) points per patient. RVI accurately localized 72.2% VT sites of origin, with median distance of 5.1 (3.2–10.1) mm. Inaccurate localization was significantly less frequent for RVI than AT (5.6% vs 33.3%; odds ratio 0.12; P = .035). Compared to RVI, distance to VT sites of origin was significantly larger for sites showing prolonged RT and ARI and were nonsignificantly larger for sites showing highest AT and ARI gradients. Conclusion RVI identifies vulnerable regions closest to VT sites of origin. Activation-repolarization metrics may improve VT substrate delineation and inform novel ablation strategies.
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Rottmann M, Kleber AG, Barkagan M, Sroubek J, Leshem E, Shapira-Daniels A, Buxton AE, Anter E. Activation During Sinus Rhythm in Ventricles With Healed Infarction: Differentiation Between Arrhythmogenic and Nonarrhythmogenic Scar. Circ Arrhythm Electrophysiol 2019; 12:e007879. [PMID: 31597477 DOI: 10.1161/circep.119.007879] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND In infarct-related ventricular tachycardia (VT), the circuit often corresponds to a location characterized by activation slowing during sinus rhythm (SR). However, the relationship between activation slowing during SR and vulnerability for reentry and correlation to components of the VT circuit are unknown. This study examined the relationship between activation slowing during SR and vulnerability for reentry and correlated these areas with components of the circuit. METHODS In a porcine model of healed infarction, the spatial distribution of endocardial activation velocity was compared between SR and VT. Isthmus sites were defined using activation and entrainment mapping as areas exhibiting diastolic activity within the circuit while bystanders were defined as areas displaying diastolic activity outside the circuit. RESULTS Of 15 swine, 9 had inducible VT (5.2±3.0 per animal) while in 6 swine VT could not be induced despite stimulation from 4 RV and LV sites at 2 drive trains with 6 extra-stimuli down to refractoriness. Infarcts with VT had a greater magnitude of activation slowing during SR. A minimal endocardial activation velocity cutoff ≤0.1 m/s differentiated inducible from noninducible infarctions (P=0.015). Regions of maximal endocardial slowing during SR corresponded to the VT isthmus (area under curve=0.84 95% CI, 0.78-0.90) while bystander sites exhibited near-normal activation during SR. VT circuits were complex with 41.7% exhibiting discontinuous propagation with intramural bridges of slow conduction and delayed quasi-simultaneous endocardial activation. Regions forming the VT isthmus borders had faster activation during SR while regions forming the inner isthmus were activated faster during VT. CONCLUSIONS Endocardial activation slowing during SR may differentiate infarctions vulnerable for VT from those less vulnerable for VT. Sites of slow activation during SR correspond to sites forming the VT isthmus but not to bystander sites.
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Affiliation(s)
- Markus Rottmann
- Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Andre G Kleber
- Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Michael Barkagan
- Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Jakub Sroubek
- Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Eran Leshem
- Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Ayelet Shapira-Daniels
- Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Alfred E Buxton
- Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Elad Anter
- Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
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Factors Promoting Conduction Slowing as Substrates for Block and Reentry in Infarcted Hearts. Biophys J 2019; 117:2361-2374. [PMID: 31521328 PMCID: PMC6990374 DOI: 10.1016/j.bpj.2019.08.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 07/03/2019] [Accepted: 08/05/2019] [Indexed: 01/11/2023] Open
Abstract
The development of effective and safe therapies for scar-related ventricular tachycardias requires a detailed understanding of the mechanisms underlying the conduction block that initiates electrical re-entries associated with these arrhythmias. Conduction block has been often associated with electrophysiological changes that prolong action potential duration (APD) within the border zone (BZ) of chronically infarcted hearts. However, experimental evidence suggests that remodeling processes promoting conduction slowing as opposed to APD prolongation mark the chronic phase. In this context, the substrate for the initial block at the mouth of an isthmus/diastolic channel leading to ventricular tachycardia is unclear. The goal of this study was to determine whether electrophysiological parameters associated with conduction slowing can cause block and re-entry in the BZ. In silico experiments were conducted on two-dimensional idealized infarct tissue as well as on a cohort of postinfarction porcine left ventricular models constructed from ex vivo magnetic resonance imaging scans. Functional conduction slowing in the BZ was modeled by reducing sodium current density, whereas structural conduction slowing was represented by decreasing tissue conductivity and including fibrosis. The arrhythmogenic potential of APD prolongation was also tested as a basis for comparison. Within all models, the combination of reduced sodium current with structural remodeling more often degenerated into re-entry and, if so, was more likely to be sustained for more cycles. Although re-entries were also detected in experiments with prolonged APD, they were often not sustained because of the subsequent block caused by long-lasting repolarization. Functional and structural conditions associated with slow conduction rather than APD prolongation form a potent substrate for arrhythmogenesis at the isthmus/BZ of chronically infarcted hearts. Reduced excitability led to block while slow conduction shortened the wavelength of propagation, facilitating the sustenance of re-entries. These findings provide important insights for models of patient-specific risk stratification and therapy planning.
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Reynard JT, Oshodi OM, Lai JC, Lai RW, Bazoukis G, Fragakis N, Letsas KP, Korantzopoulos P, Liu FZ, Liu T, Xia Y, Tse G, Li CK. Electrocardiographic conduction and repolarization markers associated with sudden cardiac death: moving along the electrocardiography waveform. Minerva Cardioangiol 2019; 67:131-144. [PMID: 30260143 DOI: 10.23736/s0026-4725.18.04775-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/11/2023]
Abstract
The QT interval along with its heart rate corrected form (QTc) are well-established ECG markers that have been found to be associated with malignant ventricular arrhythmogenesis. However, extensive preclinical and clinical investigations over the years have allowed for novel clinical ECG markers to be generated as predictors of arrhythmogenesis and sudden cardiac death. Repolarization markers include the older QTc, QT dispersion and newer Tpeak - Tend intervals, (Tpeak - Tend) / QT ratios, T-wave alternans (TWA), microvolt TWA and T-wave area dispersion. Meanwhile, conduction markers dissecting the QRS complex, such as QRS dispersion (QRSD) and fragmented QRS, were also found to correlate conduction velocity and unidirectional block with re-entrant substrates in various cardiac conditions. Both repolarization and conduction parameters can be combined into the excitation wavelength (λ). A surrogate marker for λ is the index of Cardiac Electrophysiological Balance (iCEB: QT / QRSd). Other markers based on conduction-repolarization are [QRSD x (Tpeak-Tend) / QRSd] and [QRSD x (Tpeak-Tend) / (QRSd x QT)]. Advancement in technology permitted sophisticated electrophysiological analyses such as principal component analysis and periodic repolarization dynamics to further improve risk stratification. This was closely followed by other novel indices including ventricular ectopic QRS interval, the f99 index and EntropyXQT, which integrates mathematical and physical calculations for determining the risk markers. Though proven to be effective in limited patient cohorts, more clinical studies across different cardiac pathologies are required to confirm their validity. As such, this review seeks to encapsulate the development of old and new ECG markers along with their associated utility and shortcomings in clinical practice.
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Affiliation(s)
- Jack T Reynard
- Faculty of Medicine, Newcastle University, Newcastle Upon Tyne, UK
| | | | - Jenny C Lai
- Faculty of Medicine, Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China
- Department of Medicine and Therapeutics, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong, China
| | - Rachel W Lai
- Faculty of Medicine, Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China
- Department of Medicine and Therapeutics, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong, China
| | - George Bazoukis
- Laboratory of Cardiac Electrophysiology, Second Department of Cardiology, Evangelismos General Hospital of Athens, Athens, Greece
| | - Nikolaos Fragakis
- Third Department of Cardiology, Hippokration Hospital, Medical School, Aristotle University of Thessaloniki, Thessaloniki, Greece
- First Department of Cardiology, Medical School, University of Ioannina, Ioannina, Greece
| | - Konstantinos P Letsas
- Laboratory of Cardiac Electrophysiology, Second Department of Cardiology, Evangelismos General Hospital of Athens, Athens, Greece
| | - Panagiotis Korantzopoulos
- Third Department of Cardiology, Hippokration Hospital, Medical School, Aristotle University of Thessaloniki, Thessaloniki, Greece
- First Department of Cardiology, Medical School, University of Ioannina, Ioannina, Greece
| | - Fang-Zhou Liu
- Department of Cardiovascular Surgery, Guangdong Cardiovascular Institute, Guangdong General Hospital affiliated to South China University of Technology, Guangzhou, China
| | - Tong Liu
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, China
| | - Yunlong Xia
- Department of Cardiology, First Affiliated Hospital of Dalian Medical University, Dalian, China
| | - Gary Tse
- Faculty of Medicine, Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China
- Department of Medicine and Therapeutics, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong, China
| | - Christien K Li
- Faculty of Medicine, Newcastle University, Newcastle Upon Tyne, UK -
- Faculty of Medicine, Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China
- Department of Medicine and Therapeutics, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong, China
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42
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Campos FO, Orini M, Taggart P, Hanson B, Lambiase PD, Porter B, Rinaldi CA, Gill J, Bishop MJ. Characterizing the clinical implementation of a novel activation-repolarization metric to identify targets for catheter ablation of ventricular tachycardias using computational models. Comput Biol Med 2019; 108:263-275. [PMID: 31009930 PMCID: PMC6538827 DOI: 10.1016/j.compbiomed.2019.03.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 03/08/2019] [Accepted: 03/19/2019] [Indexed: 11/24/2022]
Abstract
Identification of targets for catheter ablation of ventricular tachycardias (VTs) remains a significant challenge. VTs are often driven by re-entrant circuits resulting from a complex interaction between the front (activation) and tail (repolarization) of the electrical wavefront. Most mapping techniques do not take into account the tissue repolarization which may hinder the detection of ablation targets. The re-entry vulnerability index (RVI), a recently proposed mapping procedure, incorporates both activation and repolarization times to uncover VT circuits. The method showed potential in a series of experiments, but it still requires further development to enable its incorporation into a clinical protocol. Here, in-silico experiments were conducted to thoroughly assess RVI maps constructed under clinically-relevant mapping conditions. Within idealized as well as anatomically realistic infarct models, we show that parameters of the algorithm such as the search radius can significantly alter the specificity and sensitivity of the RVI maps. When constructed on sparse grids obtained following various placements of clinical recording catheters, RVI maps can identify vulnerable regions as long as two electrodes were placed on both sides of the line of block. Moreover, maps computed during pacing without inducing VT can reveal areas of abnormal repolarization and slow conduction but not directly vulnerability. In conclusion, the RVI algorithm can detect re-entrant circuits during VT from low resolution mapping grids resembling the clinical setting. Furthermore, RVI maps may provide information about the underlying tissue electrophysiology to guide catheter ablation without the need of inducing potentially harmful VT during the clinical procedure. Finally, the ability of the RVI maps to identify vulnerable regions with specificity in high resolution computer models could potentially improve the prediction of optimal ablation targets of simulation-based strategies. Safe and accurate detection of targets for catheter ablation remains a challenge. We conducted a thorough assessment of the Re-entry Vulnerability Index (RVI). Parameters of the algorithm can alter the specificity and sensitivity of RVI maps. When constructed on sparse grids RVI maps could still detect arrhythmogenic sites. In absence of arrhythmia, RVI maps revealed abnormal sites, but not vulnerability.
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Affiliation(s)
- Fernando O Campos
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Michele Orini
- The Heart Hospital, University College London, London, United Kingdom; Institute of Cardiovascular Science, University College London, London, United Kingdom
| | - Peter Taggart
- The Heart Hospital, University College London, London, United Kingdom; Institute of Cardiovascular Science, University College London, London, United Kingdom
| | - Ben Hanson
- Department of Mechanical Engineering, University College London, London, United Kingdom
| | - Pier D Lambiase
- Institute of Cardiovascular Science, University College London, London, United Kingdom; Electrophysiology Department, Barts Heart Centre, St Bartholomew's Hospital, London, United Kingdom
| | - Bradley Porter
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom; Department of Cardiology, Guys and St Thomas' NHS Trust, London, United Kingdom
| | | | - Jaswinder Gill
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom; Department of Cardiology, Guys and St Thomas' NHS Trust, London, United Kingdom
| | - Martin J Bishop
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom. https://kclpure.kcl.ac.uk/portal/martin.bishop.html
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Bear LR, Walton RD, Abell E, Coudière Y, Haissaguerre M, Bernus O, Dubois R. Optical Imaging of Ventricular Action Potentials in a Torso Tank: A New Platform for Non-Invasive Electrocardiographic Imaging Validation. Front Physiol 2019; 10:146. [PMID: 30863318 PMCID: PMC6399141 DOI: 10.3389/fphys.2019.00146] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 02/07/2019] [Indexed: 12/12/2022] Open
Abstract
Background: Non-invasive electrocardiographic imaging (ECGI) is a promising tool to provide high-resolution panoramic imaging of cardiac electrical activity noninvasively from body surface potential measurements. Current experimental methods for ECGI validation are limited to comparison with unipolar electrograms and the relatively low spatial resolution of cardiac mapping arrays. We aim to develop a novel experimental set up combining a human shaped torso tank with high-resolution optical mapping allowing the validation of ECGI reconstructions. Methods: Langendorff-perfused pig hearts (n = 3) were suspended in a human torso-shaped tank, with the left anterior descending artery (LAD) cannulated on a separate perfusion. Electrical signals were recorded from an 108-electrode epicardial sock and 128 electrodes embedded in the tank surface. Simultaneously, optical mapping of the heart was performed through the anterior surface of the tank. Recordings were made in sinus rhythm and ventricular pacing (n = 55), with activation and repolarization heterogeneities induced by perfusion of hot and cold solutions as well as Sotalol through the LAD. Fluoroscopy provided 3D cardiac and electrode geometries in the tank that were transformed to the 2D optical mapping window using an optimization algorithm. Epicardial unipolar electrograms were reconstructed from torso potentials using ECGI and validated using optical activation and repolarization maps. Results: The transformation and alignment of the 3D geometries onto the 2D optical mapping window was good with an average correlation of 0.87 ± 0.10 and error of 7.7 ± 3.1 ms with activation derived from the sock. The difference in repolarization times were more substantial (error = 17.4 ± 3.7 ms) although the sock and optical repolarization patterns themselves were very similar (correlation = 0.83 ± 0.13). Validation of ECGI reconstructions revealed ECGI accurately captures the pattern of activation (correlation = 0.79 ± 0.11) and identified regions of late and/or early repolarization during different perfusions through LAD. ECGI also correctly demonstrated gradients in both activation and repolarization, although in some cases these were under or over-estimated or shifted slightly in space. Conclusion: A novel experimental setup has been developed, combining a human-shaped torso tank with optical mapping, which can be effectively used in the validation of ECGI techniques; including the reconstruction of activation and repolarization patterns and gradients.
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Affiliation(s)
- Laura R Bear
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France.,Univ. Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux, France.,INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux, France
| | - Richard D Walton
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France.,Univ. Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux, France.,INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux, France
| | - Emma Abell
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France.,Univ. Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux, France.,INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux, France
| | - Yves Coudière
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France.,Univ. Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux, France.,CARMEN Research Team, INRIA, Talence, France.,CNRS, IMB, UMR 5251, Talence, France
| | - Michel Haissaguerre
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France.,Univ. Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux, France.,INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux, France.,Bordeaux University Hospital (CHU), Electrophysiology and Ablation Unit, Pessac, France
| | - Olivier Bernus
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France.,Univ. Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux, France.,INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux, France
| | - Rémi Dubois
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France.,Univ. Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux, France.,INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux, France
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44
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Martin CA, Orini M, Srinivasan NT, Bhar-Amato J, Honarbakhsh S, Chow AW, Lowe MD, Ben-Simon R, Elliott PM, Taggart P, Lambiase PD. Assessment of a conduction-repolarisation metric to predict Arrhythmogenesis in right ventricular disorders. Int J Cardiol 2018; 271:75-80. [PMID: 29871808 PMCID: PMC6152588 DOI: 10.1016/j.ijcard.2018.05.063] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 05/16/2018] [Accepted: 05/18/2018] [Indexed: 11/22/2022]
Abstract
BACKGROUND The re-entry vulnerability index (RVI) is a recently proposed activation-repolarization metric designed to quantify tissue susceptibility to re-entry. This study aimed to test feasibility of an RVI-based algorithm to predict the earliest endocardial activation site of ventricular tachycardia (VT) during electrophysiological studies and occurrence of haemodynamically significant ventricular arrhythmias in follow-up. METHODS Patients with Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) (n = 11), Brugada Syndrome (BrS) (n = 13) and focal RV outflow tract VT (n = 9) underwent programmed stimulation with unipolar electrograms recorded from a non-contact array in the RV. RESULTS Lowest values of RVI co-localised with VT earliest activation site in ARVC/BrS but not in focal VT. The distance between region of lowest RVI and site of VT earliest site (Dmin) was lower in ARVC/BrS than in focal VT (6.8 ± 6.7 mm vs 26.9 ± 13.3 mm, p = 0.005). ARVC/BrS patients with inducible VT had lower Global-RVI (RVIG) than those who were non-inducible (-54.9 ± 13.0 ms vs -35.9 ± 8.6 ms, p = 0.005) or those with focal VT (-30.6 ± 11.5 ms, p = 0.001). Patients were followed up for 112 ± 19 months. Those with clinical VT events had lower Global-RVI than both ARVC and BrS patients without VT (-54.5 ± 13.5 ms vs -36.2 ± 8.8 ms, p = 0.007) and focal VT patients (-30.6 ± 11.5 ms, p = 0.002). CONCLUSIONS RVI reliably identifies the earliest RV endocardial activation site of VT in BrS and ARVC but not focal ventricular arrhythmias and predicts the incidence of haemodynamically significant arrhythmias. Therefore, RVI may be of value in predicting VT exit sites and hence targeting of re-entrant arrhythmias.
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Affiliation(s)
- C A Martin
- Barts Heart Centre, Barts Health NHS Trust, West Smithfield, London EC1A 7BE, UK; Institute of Cardiovascular Science, University College London, Gower Street, London WC1E 6BT, UK
| | - M Orini
- Barts Heart Centre, Barts Health NHS Trust, West Smithfield, London EC1A 7BE, UK; Institute of Cardiovascular Science, University College London, Gower Street, London WC1E 6BT, UK
| | - N T Srinivasan
- Barts Heart Centre, Barts Health NHS Trust, West Smithfield, London EC1A 7BE, UK; Institute of Cardiovascular Science, University College London, Gower Street, London WC1E 6BT, UK
| | - J Bhar-Amato
- Institute of Cardiovascular Science, University College London, Gower Street, London WC1E 6BT, UK
| | - S Honarbakhsh
- Barts Heart Centre, Barts Health NHS Trust, West Smithfield, London EC1A 7BE, UK
| | - A W Chow
- Barts Heart Centre, Barts Health NHS Trust, West Smithfield, London EC1A 7BE, UK
| | - M D Lowe
- Barts Heart Centre, Barts Health NHS Trust, West Smithfield, London EC1A 7BE, UK
| | - R Ben-Simon
- Barts Heart Centre, Barts Health NHS Trust, West Smithfield, London EC1A 7BE, UK
| | - P M Elliott
- Barts Heart Centre, Barts Health NHS Trust, West Smithfield, London EC1A 7BE, UK
| | - P Taggart
- Institute of Cardiovascular Science, University College London, Gower Street, London WC1E 6BT, UK
| | - P D Lambiase
- Barts Heart Centre, Barts Health NHS Trust, West Smithfield, London EC1A 7BE, UK; Institute of Cardiovascular Science, University College London, Gower Street, London WC1E 6BT, UK.
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45
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Coronel R. Activation-repolarization mapping to guide VT-ablation without the need to induce the arrhythmia. Int J Cardiol 2018; 271:111-112. [PMID: 29980370 DOI: 10.1016/j.ijcard.2018.06.058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 06/13/2018] [Indexed: 10/28/2022]
Affiliation(s)
- Ruben Coronel
- Department of Experimental Cardiology, Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands; IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, F-33600 Pessac-Bordeaux, France.
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46
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Tse G, Gong M, Meng L, Wong CW, Bazoukis G, Chan MTV, Wong MCS, Letsas KP, Baranchuk A, Yan GX, Liu T, Wu WKK. Predictive Value of T peak - T end Indices for Adverse Outcomes in Acquired QT Prolongation: A Meta-Analysis. Front Physiol 2018; 9:1226. [PMID: 30233403 PMCID: PMC6129769 DOI: 10.3389/fphys.2018.01226] [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: 05/14/2018] [Accepted: 08/14/2018] [Indexed: 01/13/2023] Open
Abstract
Background: Acquired QT interval prolongation has been linked with malignant ventricular arrhythmias, such as torsade de pointes, in turn predisposing to sudden cardiac death. Increased dispersion of repolarization has been identified as a pro-arrhythmic factor and can be observed as longer Tpeak - Tend interval and higher Tpeak - Tend/QT ratio on the electrocardiogram. However, the values of these repolarization indices for predicting adverse outcomes in this context have not been systematically evaluated. Method: PubMed, Embase and Cochrane Library databases were searched until 14th February 2018, identifying 232 studies. Results: Five studies on acquired QT prolongation met the inclusion criteria and 308 subjects with drug-induced LQTS patients (mean age: 66 ± 18 years old; 46% male) were included in this meta-analysis. Tpeak - Tend intervals were longer [mean difference [MD]: 76 ms, standard error [SE]: 26 ms, P = 0.003; I2 = 98%] and Tpeak - Tend/QT ratios were higher (MD: 0.14, SE: 0.03, P = 0.000; I2 = 29%) in patients with torsade de pointes compared to those without these events. Conclusion: Tpeak - Tend interval and Tpeak - Tend/QT ratio were higher in patients with acquired QT prolongation suffering from torsade de pointes compared to those who did not. These repolarization indices may provide additional predictive value for identifying high-risk individuals.
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Affiliation(s)
- Gary Tse
- Department of Medicine and Therapeutics, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong, Hong Kong.,Li Ka Shing Institute of Health Sciences, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong, Hong Kong
| | - Mengqi Gong
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, Hong Kong
| | - Lei Meng
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, Hong Kong
| | - Cheuk W Wong
- Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, Hong Kong
| | - George Bazoukis
- Laboratory of Cardiac Electrophysiology, Second Department of Cardiology, Evangelismos General Hospital of Athens, Athens, Greece
| | - Matthew T V Chan
- Department of Anaesthesia and Intensive Care, Chinese University of Hong Kong, Hong Kong, Hong Kong
| | - Martin C S Wong
- JC School of Public Health and Primary Care, Chinese University of Hong Kong, Hong Kong, Hong Kong
| | - Konstantinos P Letsas
- Laboratory of Cardiac Electrophysiology, Second Department of Cardiology, Evangelismos General Hospital of Athens, Athens, Greece
| | - Adrian Baranchuk
- Division of Cardiology, Kingston General Hospital, Queen's University, Kingston, ON, Canada
| | - Gan-Xin Yan
- Lankenau Institute for Medical Research and Lankenau Medical Center, Wynnewood, PA, United States.,Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Tong Liu
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, Hong Kong
| | - William K K Wu
- Department of Anaesthesia and Intensive Care, Chinese University of Hong Kong, Hong Kong, Hong Kong
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Orini M, Taggart P, Lambiase PD. In vivo human sock-mapping validation of a simple model that explains unipolar electrogram morphology in relation to conduction-repolarization dynamics. J Cardiovasc Electrophysiol 2018; 29:990-997. [PMID: 29660191 PMCID: PMC6055721 DOI: 10.1111/jce.13606] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Revised: 03/29/2018] [Accepted: 04/09/2018] [Indexed: 12/16/2022]
Abstract
INTRODUCTION The unipolar electrogram (UEG) provides local measures of cardiac activation and repolarization and is an important translational link between patient and laboratory. A simple theoretical model of the UEG was previously proposed and tested in silico. METHOD AND RESULTS The aim of this study was to use epicardial sock-mapping data to validate the simple model's predictions of unipolar electrogram morphology in the in vivo human heart. The simple model conceptualizes the UEG as the difference between a local cardiac action potential and a position-independent component representing remote activity, which is defined as the average of all action potentials. UEGs were recorded in 18 patients using a multielectrode sock containing 240 electrodes and activation (AT) and repolarization time (RT) were measured using standard definitions. For each cardiac site, a simulated local action potential was generated by adjusting a stylized action potential to fit AT and RT measured in vivo. The correlation coefficient (cc) measuring the morphological similarity between 13,637 recorded and simulated UEGs was cc = 0.89 (0.72-0.95), median (Q1 -Q3 ), for the entire UEG, cc = 0.90 (0.76-0.95) for QRS complexes, and cc = 0.83 (0.58-0.92) for T-waves. QRS and T-wave areas from recorded and simulated UEGs showed cc> 0.89 and cc> 0.84, respectively, indicating good agreement between voltage isochrones maps. Simulated UEGs accurately reproduced the interaction between AT and QRS morphology and between RT and T-wave morphology observed in vivo. CONCLUSIONS Human in vivo whole heart data support the validity of the simple model, which provides a framework for improving the understanding of the UEG and its clinical utility.
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Affiliation(s)
- Michele Orini
- Department of Mechanical Engineering, University College London, London, United Kingdom.,Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew's Hospital, London, United Kingdom
| | - Peter Taggart
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew's Hospital, London, United Kingdom.,Institute of Cardiovascular Science, University College London, London, United Kingdom
| | - Pier D Lambiase
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew's Hospital, London, United Kingdom.,Institute of Cardiovascular Science, University College London, London, United Kingdom
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48
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Bernikova OG, Sedova KA, Arteyeva NV, Ovechkin AO, Kharin SN, Shmakov DN, Azarov JE. Repolarization in perfused myocardium predicts reperfusion ventricular tachyarrhythmias. J Electrocardiol 2018; 51:542-548. [DOI: 10.1016/j.jelectrocard.2017.12.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Indexed: 11/30/2022]
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49
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Mendonca Costa C, Plank G, Rinaldi CA, Niederer SA, Bishop MJ. Modeling the Electrophysiological Properties of the Infarct Border Zone. Front Physiol 2018; 9:356. [PMID: 29686626 PMCID: PMC5900020 DOI: 10.3389/fphys.2018.00356] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 03/22/2018] [Indexed: 12/28/2022] Open
Abstract
Ventricular arrhythmias (VA) in patients with myocardial infarction (MI) are thought to be associated with structural and electrophysiological remodeling within the infarct border zone (BZ). Personalized computational models have been used to investigate the potential role of the infarct BZ in arrhythmogenesis, which still remains incompletely understood. Most recent models have relied on experimental data to assign BZ properties. However, experimental measurements vary significantly resulting in different computational representations of this region. Here, we review experimental data available in the literature to determine the most prominent properties of the infarct BZ. Computational models are then used to investigate the effect of different representations of the BZ on activation and repolarization properties, which may be associated with VA. Experimental data obtained from several animal species and patients with infarct show that BZ properties vary significantly depending on disease's stage, with the early disease stage dominated by ionic remodeling and the chronic stage by structural remodeling. In addition, our simulations show that ionic remodeling in the BZ leads to large repolarization gradients in the vicinity of the scar, which may have a significant impact on arrhythmia simulations, while structural remodeling plays a secondary role. We conclude that it is imperative to faithfully represent the properties of regions of infarction within computational models specific to the disease stage under investigation in order to conduct in silico mechanistic investigations.
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Affiliation(s)
- Caroline Mendonca Costa
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Gernot Plank
- Department of Biophysics, Medical University of Graz, Graz, Austria
| | | | - Steven A Niederer
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Martin J Bishop
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
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50
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Tse G, Yan BP. Traditional and novel electrocardiographic conduction and repolarization markers of sudden cardiac death. Europace 2018; 19:712-721. [PMID: 27702850 DOI: 10.1093/europace/euw280] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 08/11/2016] [Indexed: 12/20/2022] Open
Abstract
Sudden cardiac death, frequently due to ventricular arrhythmias, is a significant problem globally. Most affected individuals do not arrive at hospital in time for medical treatment. Therefore, there is an urgent need to identify the most-at-risk patients for insertion of prophylactic implantable cardioverter defibrillators. Clinical risk markers derived from electrocardiography are important for this purpose. They can be based on repolarization, including corrected QT (QTc) interval, QT dispersion (QTD), interval from the peak to the end of the T-wave (Tpeak - Tend), (Tpeak - Tend)/QT, T-wave alternans (TWA), and microvolt TWA. Abnormal repolarization properties can increase the risk of triggered activity and re-entrant arrhythmias. Other risk markers are based solely on conduction, such as QRS duration (QRSd), which is a surrogate marker of conduction velocity (CV) and QRS dispersion (QRSD) reflecting CV dispersion. Conduction abnormalities in the form of reduced CV, unidirectional block, together with a functional or a structural obstacle, are conditions required for circus-type or spiral wave re-entry. Conduction and repolarization can be represented by a single parameter, excitation wavelength (λ = CV × effective refractory period). λ is an important determinant of arrhythmogenesis in different settings. Novel conduction-repolarization markers incorporating λ include Lu et al.' index of cardiac electrophysiological balance (iCEB: QT/QRSd), [QRSD× (Tpeak - Tend)/QRSd] and [QRSD × (Tpeak - Tend)/(QRSd × QT)] recently proposed by Tse and Yan. The aim of this review is to provide up to date information on traditional and novel markers and discuss their utility and downfalls for risk stratification.
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Affiliation(s)
- Gary Tse
- Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, SAR, P.R. China
| | - Bryan P Yan
- Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, SAR, P.R. China.,Department of Epidemiology and Preventive Medicine, Monash University, Clayton, VIC, Australia
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