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ORIGINAL RESEARCH article

Front. Physiol.
Sec. Cardiac Electrophysiology
Volume 15 - 2024 | doi: 10.3389/fphys.2024.1428709

The arrhythmic substrate of hypertrophic cardiomyopathy using ECG imaging

Provisionally accepted
Ji-Jian Chow Ji-Jian Chow 1*Kevin M. Leong Kevin M. Leong 1Matthew Shun-Shin Matthew Shun-Shin 1Sian Jones Sian Jones 1Oliver P. Guttmann Oliver P. Guttmann 2Sam Mohiddin Sam Mohiddin 2Pier Lambiase Pier Lambiase 2Perry M. Elliott Perry M. Elliott 2Julian O. Ormerod Julian O. Ormerod 3Michael Koa-Wing Michael Koa-Wing 1David Lefroy David Lefroy 1Phang Boon Lim Phang Boon Lim 1Nicholas W. Linton Nicholas W. Linton 1Fu Siong Ng Fu Siong Ng 1Norman A. Qureshi Norman A. Qureshi 1Zachary I. Whinnett Zachary I. Whinnett 1Nicholas S. Peters Nicholas S. Peters 1Darrel P. Francis Darrel P. Francis 1Amanda M. Varnava Amanda M. Varnava 1Prapa Kanagaratnam Prapa Kanagaratnam 1
  • 1 Imperial College London, London, United Kingdom
  • 2 Barts Heart Centre, London, England, United Kingdom
  • 3 Oxford University Hospitals NHS Trust, Oxford, England, United Kingdom

The final, formatted version of the article will be published soon.

    Patients with hypertrophic cardiomyopathy (HCM) are at risk of lethal ventricular arrhythmia but the electrophysiological substrate behind this is not well understood. We used non-invasive electrocardiographic imaging to characterize patients with HCM, including cardiac arrest survivors. HCM patients surviving ventricular fibrillation or hemodynamically unstable ventricular tachycardia (n=17) were compared to HCM patients without a personal history of potentially lethal arrhythmia (n=20) and a pooled control group with structurally normal hearts. Subjects underwent exercise testing with non-invasive electrocardiographic imaging to estimate epicardial electrophysiology. Visual inspection of reconstructed epicardial HCM maps revealed isolated patches of late activation time (AT), prolonged activation recovery intervals (ARI), as well as reversal of apico-basal trends in T wave inversion and ARI compared to controls (p<0.005 for all). AT and ARI were compared between groups. The pooled HCM group had longer mean AT (60.1ms vs 52.2ms, p<0.001), activation dispersion (55.2ms vs 48.6ms, p=0.026), and mean ARI (227ms vs 217ms, p=0.016) than normal heart controls. HCM ventricular arrhythmia survivors could be differentiated from HCM patients without personal history of life-threatening arrhythmia by longer mean AT (63.2ms vs 57.4ms, p=0.007), steeper activation gradients (0.45ms/mm vs 0.36ms/mm, p=0.011), and longer mean ARI (234.0ms vs 221.4ms, p=0.026). A logistic regression model including whole heart mean activation time and activation-recovery interval could identify the ventricular arrhythmia survivors from the HCM cohort, producing a C-statistic of 0.76 (95% confidence interval 0.72-0.81), with optimal sensitivity 78.6% and specificity of 79.8%. The HCM epicardial electrotype is characterized by delayed, dispersed conduction and prolonged, dispersed activation-recovery intervals. Combination of electrophysiologic measures by logistic regression can improve differentiation over single variables. Future studies could test such models prospectively for risk stratification of sudden death in HCM.

    Keywords: Hypertrophic Cardiomyopathy, sudden death, Electrocardiographic imaging, Implantable defibrillator, risk stratification

    Received: 06 May 2024; Accepted: 17 Jul 2024.

    Copyright: © 2024 Chow, Leong, Shun-Shin, Jones, Guttmann, Mohiddin, Lambiase, Elliott, Ormerod, Koa-Wing, Lefroy, Lim, Linton, Ng, Qureshi, Whinnett, Peters, Francis, Varnava and Kanagaratnam. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Ji-Jian Chow, Imperial College London, London, United Kingdom

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