correlation between electrocardiographic and histopathological changes in isoprenaline-induced myocardial injury

myocardial injury was induced in 25 dogs by infusing isoprenaline, 2-4 microgram per kg per minute for the duration of six hours. 10 dogs served as controls which received only physiological saline. animals receiving isoprenaline 2 microgram per kg per minute were labelled as experimental group a and other receiving microgram per kg per minute as experimental group b. histopathological observations in experimental groups a & b showed subendocardial haemorrhage in the papillary muscles and apex of left ventricle as early as two-three hours of infusion. focal lesions characterized by congestion, dilatation and extravasation of blood was observed near necrotic myocardium. group a animals showed only severe tachycardia while in group b myocardial infarction in 80% and only ischaemic changes in 20% of animals were observed. out of animals in group b, 37.5% developed myocardial infarction after two hours of infusion while remaining 62.5% developed changes after four hours. histopathological changes were very well correlated with ecg findings observed in the present study.