Ranolazine modulates action potential parameters of human atrial myocytes.

Increased late sodium current (INaL) may play a role in action potential (AP) prolongation and arrhythmogenesis. By inhibiting INaL, Ranolazine (RAN) attenuates AP prolongation and reduces sodium/calcium overload in myocytes with enhanced INaL. No data exist about RAN effect in human cardiomyocytes. Electrophysiological effects of RAN (3-10µM) was assessed in human atrial myocytes (HuAM), from biopsies of patients undergoing cardiac surgery. APs stimulated at 0.2-1Hz were recorded in the perforated-patch configuration; duration was measured at -50mV (APD50) or 90% repolarization (APD90). Values are reported in Table as mean±SEM (*P<0.05, RAN vs. Control, n=13-18).