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Dynamic spatial dispersion of repolarization is present in regions critical for ischemic ventricular tachycardia ablation

Srinivasan, NT; Garcia, J; Schilling, RJ; Ahsan, S; Hunter, RJ; Lowe, M; Chow, AW; (2021) Dynamic spatial dispersion of repolarization is present in regions critical for ischemic ventricular tachycardia ablation. Heart Rhythm O2 , 2 (3) pp. 280-289. 10.1016/j.hroo.2021.05.003. Green open access

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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.

Type: Article
Title: Dynamic spatial dispersion of repolarization is present in regions critical for ischemic ventricular tachycardia ablation
Location: United States
Open access status: An open access version is available from UCL Discovery
DOI: 10.1016/j.hroo.2021.05.003
Publisher version: https://doi.org/10.1016/j.hroo.2021.05.003
Language: English
Additional information: © 2021 Heart Rhythm Society. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
Keywords: Ablation, Dispersion of repolarization, Late potentials, Substrate mapping, Ventricular repolarization, Ventricular repolarization mapping, Ventricular tachycardia
UCL classification: UCL
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > Institute of Cardiovascular Science
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > Institute of Cardiovascular Science > Clinical Science
URI: https://discovery.ucl.ac.uk/id/eprint/10138039
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