Ventricular tachyarrhythmias induced by premature beats during acute coronary occlusion

Abstract

Summary Ventricular tachyarrhythmias were induced in the ventricle during acute coronary occlusion by initiating closely coupled premature beats in the normal or ischemic areas. Acute coronary occlusion produced an initial decrease in the refractory period and conduction time in the affected area within about 3 min. of the start of coronary occlusion, followed by a subsequent increase in these parameters. Ventricular premature beats of the shortest coupling intervals could be initiated in the ischemic area during the initial phase of acute coronary occlusion when the refractory period was shortest, and these premature beats, in turn, induced ventricular tachyarrhythmias with an average time of 3 min 6 sec after the start of coronary occlusion. When the refractory period was subsequently increased in the ischemic area, ventricular premature beats of the shortest coupling intervals could be initiated in the normal area and these premature beats resulted in ventricular tachyarrhythmias with an average time of 7 min 10 sec after the start of coronary occlusion. The results indicate that ventricular premature beats initiated in the ischemic area are more likely to induce the tachyarrhythmias in the initial phase of acute coronary occlusion, while the premature beats initiated in the normal area are more likely to lead to ventricular tachyarrhythmias in the later stages of acute coronary occlusion.