REGIONAL EXPANSION DURING MYOCARDIAL-ISCHEMIA PREDICTS VENTRICULAR-FIBRILLATION AND CORONARY REOCCLUSION

Primary ventricular fibrillation (VF) complicating acute myocardial in farction is associated with occluded infarction-related arteries. The relationship between VF during ischemia and spontaneous coronary reocc lusion was analyzed in 48 anesthetized pigs submitted to 48 min of cor onary ligation and 6 h of reflow. Reocclusion was associated with isch emic VF (6 of 11 animals with VF but only 6 of 37 without it had reocc lusion) but not with reperfusion arrhythmias, the size of the ischemic area, the magnitude of electrocardiogram changes or contractile dysfu nction during ischemia, or the severity of intimal injury at the occlu sion site. The increase in end-diastolic length in the ischemic region during coronary occlusion was associated with ischemic VF (15 min aft er occlusion, end-diastolic length was 116 +/- 2 and 111 +/- 1% of bas eline in animals with or without presenting subsequent VF, respectivel y) and was retained by multiple logistic regression analysis as the on ly independent predictor of ischemic VF and reocclusion. Thus ischemic VF is strongly associated with an increased rate of spontaneous coron ary reocclusion during subsequent reperfusion. Acute expansion of isch emic myocardium appears as a prominent determinant of both ischemic VF and reocclusion.