Transmural differences in rate adaptation of repolarization duration quantified from ECG repolarization interval dynamics

Abstract:

Rate adaptation of repolarization duration has been shown to provide relevant information for arrhythmic risk stratification. In this work we investigate rate adaptation of QT interval, T wave width (Tω), and distance from peak to end of the T wave (Tpe), in response to step like HR changes induced during tilt test. QT and Tω presented a pronounced memory effect completed in two phases: a fast initial one and a subsequent slow accommodation (mean time for QT to complete 90% of the change was 77.0 ± 20.6 s); while Tpe, considered a measure of transmural dispersion of repolarization, presents only a fast change, practically synchronous with HR change. Based on this finding, we propose a method to indirectly compute differences in APD restitution slopes of the midmiocardial cells (αm) and epicardial cells (αe) by making only use of the surface ECG: Δα = (αm - αe) = ΔTpe/ΔRR. In our study, the mean of ΔTpe/ΔRR across recordings is 0.0371 ± 0.0327 ms/ms, which are in agreement with theoretical studies in human ventricle (ten Tusscher 2006 model), where mean Δα is 0.0364 for the same RR range.

Año de publicación:

2009

Keywords:

Fuente:

scopus