Abstract
The influence of ischemic zone size and hemodynamics on the reperfusion-induced arrhythmia in the anesthetized rat heart was examined. The heart was subjected to regional ischemia for 4 min by the occlusion of LAD followed by reperfusion for 7 min. After the reperfusion, 64% of the rats died due to irreversible VF. The size of the ischemic zone, the increase in heart rate during ischemia and the incidence of ischemic arrhythmia (VPBs and/or VT) of the animals that died after the reperfusion were significantly greater or higher than those of the surviving animals. There were positive correlations between the size of the ischemic zone and the increase of heart rate during ischemia and the incidence of ischemic arrhythmia. These results indicate that the size of the ischemic zone is a main factor that determines the degree of reperfusion-induced arrhythmia and also contributes to the increase in heart rate and the occurrence of arrhythmia during ischemia. Therefore, in addition to monitoring the blood pressure, heart rate and electrocardiogram, measurement of the size of the ischemic zone is essential for the evaluation of drug effects on reperfusion-induced arrhythmia using this animal model.
