Selective Block of Sarcolemmal IKATP in Human Cardiomyocytes Using HMR 1098

Purpose: Activation of the myocardial, ATP-dependent potassium current (IKATP) during ischemia causes shortening of the action potential duration thereby increasing dispersion of repolarization between ischemic and non-ischemic myocardium and predisposing to reentrant arrhythmias. The IKATP inhibitor HMR1098 allows selective block of the sarcolemmal myocardial KATP-channel in various animal species. Therefore, we studied the concentration and pH-dependence of HMR1098 in human ventricular myocytes.