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Ventricular Stimulus Site Influences Dynamic Dispersion of Repolarization In The Intact Human Heart

Srinivasan, NT; Orini, M; Simon, RB; Providência, R; Khan, F; Segal, OR; Babu, G; ... Lambiase, P; + view all (2016) Ventricular Stimulus Site Influences Dynamic Dispersion of Repolarization In The Intact Human Heart. American Journal of Physiology - Heart and Circulatory Physiology , 311 (3) H545-H554. 10.1152/ajpheart.00159.2016. Green open access

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Abstract

The spatial variation in restitution properties in relation to varying stimulus site is poorly defined. This study aimed to investigate the effect of varying stimulus site on apico-basal and transmural activation time (AT), action potential duration (APD) and repolarization time (RT) during restitution studies in the intact human heart. Ten patients with structurally normal hearts, undergoing clinical electrophysiology studies were enrolled. Decapolar catheters were placed apex to base in the endocardial right ventricle (RVendo) and left ventricle (LVendo), and an LV branch of the coronary sinus (LVepi) for transmural recording. S1-S2 restitution protocols were performed pacing RVendo apex, LVendo base and LVepi base. Overall 725 restitution curves were analyzed, 74% of slopes had an Smax>1 (p < 0.001), mean Smax=1.76. APD was shorter in the LVepi compared to LVendo regardless of pacing site (30ms difference during RVendo pacing, 25ms during LVendo and 48ms during LVepi; 50(th) quantile, p<0.01). Basal LVepi pacing resulted in a significant transmural gradient of RT (77ms, 50(th) quantile: p<0.01), due to loss of negative transmural AT-APD coupling (mean slope 0.63±0.3). No significant transmural gradient in RT was demonstrated during endocardial RV or LV pacing, with preserved negative transmural AT-APD coupling (mean slope -1.36 ±1.9 and -0.71 ±0.4, respectively). Steep ARI restitution slopes predominate in the normal ventricle and dynamic ARI, RT gradients exist which are modulated by the site of activation. Epicardial stimulation to initiate ventricular activation promotes significant transmural gradients of repolarization that could be pro-arrhythmic.

Type: Article
Title: Ventricular Stimulus Site Influences Dynamic Dispersion of Repolarization In The Intact Human Heart
Open access status: An open access version is available from UCL Discovery
DOI: 10.1152/ajpheart.00159.2016
Publisher version: http://dx.doi.org/10.1152/ajpheart.00159.2016
Language: English
Additional information: Licensed under Creative Commons Attribution CC-BY 3.0: © the American Physiological Society.
Keywords: APD Heterogeneity, Dispersion of Repolarization, Human, Restitution, Whole Heart
UCL classification: UCL
UCL > Provost and Vice Provost Offices
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
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
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > Institute of Cardiovascular Science > Population Science and Experimental Medicine
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > Institute of Cardiovascular Science > Population Science and Experimental Medicine > MRC Unit for Lifelong Hlth and Ageing
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > Institute of Health Informatics
URI: https://discovery.ucl.ac.uk/id/eprint/1503802
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