Coronary artery reperfusion. I. Early effects on local myocardial function and the extent of myocardial necrosis.

The effects of coronary artery reperfusion 3 hr after coronary occlusion on contractile function and the development of myocardial damage at 24 hr was studied experimentally. In 14 control and 6 reperfused dogs, relationships between epicardial ST segment elevation 15 min after coronary occlusion and myocardial creatine phosphokinase activity (CPK) and histologic appearance 24 hr later were examined. The electrocardiograms were recorded from 10 to 15 sites on the left ventricular epicardium and transmural samples for CPK and histology were obtained from the same sites where epicardial electrocardiograms had been recorded. An inverse relation existed between ST segment elevation (mv) 15 min after occlusion and log CPK activity (IU/ mg of protein) 24 hr later, log CPK = - 0.06ST + 1.26. In dogs subjected to coronary artery reperfusion, there was significantly less CPK depression (log CPK = - 0.01ST + 1.31, [P < 0.01]) than that expected from the control group. In the control group 97% of specimens showing ST segment elevations over 2 mv at 15 min showed abnormal histology 24 hr later. In contrast, in the reperfused group 43% of sites exhibiting elevated ST segment at 15 min showed abnormal histology 24 hr later. In six additional dogs it was shown that the paradoxical movement of the left ventricular wall could be reversed within 1 hr of perfusion. Therefore, by enzymatic and histologic criteria, as well as by functional assessment, coronary artery reperfusion 3 hr after occlusion resulted in salvage of myocardial tissue.