Steep repolarization time gradients in pig hearts cause distinct changes in composite electrocardiographic T-wave parameters

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Abstract

Background: The T wave of the electrocardiogram (ECG) reflects ventricular repolarization. Repolarization heterogeneity is associated with reentrant arrhythmias. Several T-wave markers (including QT interval) have been associated with ventricular arrhythmias, but studies linking such markers to underlying local repolarization time (RT) inhomogeneities are lacking. We aimed to investigate the relation of several T-wave markers to controlled drug-induced regional RT gradients in intact pig hearts. Methods: Repolarization time gradients were created by regional infusion of dofetilide and pinacidil in four atrially paced porcine Langendorff-perfused hearts placed inside a torso tank. From the 12-lead ECG on the torso tank, the mean, maximum, and dispersion (max–min) of QTtime, JTtime, Tpeak–end, Twidth, TQratio, dV/dtmax, Tarea, Tamp, and T-upslope duration were determined, as well as upslope end difference between leads V1 and V6. Results: Temporal T-wave parameters Tpeak–end, Twidth, and TQratio show a significant and high correlation with RT gradient, best reflected by mean value. Tarea (mean, max and dispersion) and dV/dtmax dispersion show only a moderate significant correlation. T-upslope duration shows a significant correlation in particular for mean values. Mean, maximum, or dispersion of QTtime and V1–V6 upslope end difference were not significantly correlated with RT gradient. Conclusion: Composite 12-lead ECG T-wave parameters Tpeak–end, Twidth, TQratio, upslope duration, and Tarea show a good correlation with underlying RT heterogeneity, whereas standard clinical metrics such as QTtime do not reflect local RT heterogeneity. The composite T-wave metrics may thus provide better insights in arrhythmia susceptibility than traditional QTtime metrics.
Original languageEnglish
Article numbere12994
JournalAnnals of noninvasive electrocardiology
Volume27
Issue number6
Early online date2022
DOIs
Publication statusPublished - Nov 2022

Keywords

  • 12-lead ECG
  • T/Tpe
  • cardiac repolarization
  • electrophysiology
  • repolarization heterogeneity
  • torso tank

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