Effect of E4031, a Class III Antiarrhythmic Drug, on Ischemia- and Reperfusion-induced Arrhythmias in Isolated Rat Hearts.

Abstract

60, E4031: 30%, n.s.), but reperfusion-induced ventricular tachyarrhythmias were sustained longer by the administration of E4031 (CONTROL: 255, E4031: 623 sec, p < 0.05). Prior exposure to E4031 decreased the depletion of high energy phosphates during ischemia, but suppressed their recovery during reperfusion. These results suggest that the attenuated loss of K+ from the ischemic myocardium and the decrease in heart rate by E4031 contributed to the reduction of ischemia-induced arrhythmias. However, the increase in myocardial Ca2+ uptake and altered energy metabolism may be responsible for the increase in reperfusion-induced arrhythmias.