Action potential clamp fingerprints of K⁺ currents in canine cardiomyocytes: their role in ventricular repolarization

Abstract

Terminal repolarization is dominated by I(K1), but action potential duration is influenced by several ion currents simultaneously. As I(to) was not active during the plateau, and neither I(K1) nor I(Kr) was frequency-dependent, other currents must be responsible for the frequency dependence of action potential duration at normal and slow heart rates in canine ventricular cells.