The computer model of ventricular activation was used to study the effects of eventual differences in the repolarization pattern between the right and the left ventricle, as well as between the apical and the basal parts of the ventricles. All changes in model action potential durations (APDs) were performed in the range corresponding to the APD variability measured in myocytes. The vectorcar-diographical spatial T loop was very sensitive on the changes in the right to left ventricular gradient of APD, while the similar changes in the apico-basal gradient of APD influenced the T loop minimally.