Assessment of ventricular repolarization alterations in subjects with early repolarization

Background: Although the electrocardiographic (ECG) features of early repolarization (ER) have been studied extensively, no systematic quantification of ventricular repolarization in subjects with ER has been conducted so far. Methods: The objective of the present study was to evaluate ECG and spatial vectorcardiographic (VCG) descriptors of ventricular repolarization in ER subjects and to associate them with the respective indices of ventricular depolarization. A digital 12-lead surface ECG was obtained from 108 young, healthy men with ER and 108 age-matched healthy controls. The maximum Q-onset–T-end interval (QT maximum), the maximum Q-onset–T-peak interval (QTp maximum), the respective QT dispersion values (QT maximum–QT minimum), the rate-corrected QTC maximum and QTpC maximum, the QRS duration, and the VCG markers spatial T amplitude, spatial QRS amplitude and spatial QRS–T angle, were evaluated in ER subjects and controls. Results: QT maximum (P=0.05) and QTp maximum (P=0.003) were higher in ER subjects than in controls, while QTC maximum (P<0.0001) and QTpC maximum (P=0.002) were lower in ER subjects than in controls. The QRS duration (P=0.013), as well as the spatial T amplitude, the spatial QRS amplitude, and the spatial QRS–T angle were higher in ER subjects than in controls (P<0.0001). The spatial T amplitude was not associated with the indices of ventricular depolarization neither in ER subjects, nor in controls. Conclusions: Ventricular repolarization, as well as depolarization, is altered in young, healthy males with ER compared to age-matched healthy controls. Ventricular depolarization and repolarization indices in ER subjects are not associated to each other.