Correlation between biochemical and contractile changes after myocardial ischemia and revascularization.

Regional contractility measured as myocardial fiber shortening ceased 15-30 sec after coronary occlusion; myocardial ATP content was unaltered at this time. Contractility returned promptly if occlusion was released within 45 min. With occlusion of 1-3 hr, delayed recovery of contractility was observed 2 weeks after reperfusion; the extent of recovery diminshed with increasing period of occlusion. Concomitantly, there was parallel recovery of synthesis of ATP and creatine phosphate (CP) in reperfused myocardium.