Patients With Acute Myocardial Infarction

Myoglobin (Mb) is a protein that enters rapidly and is rapidly cleared from plasma after coronary reperfusion. We sought to determine the accuracy with which a rapid rise in plasma [Mb] could predict successful coronary artery reopening in patients undergoing coronary arteriography in conjunction with attempted reperfusion in acute myocardial infarction. In 42 patients, plasma Mb levels were measured before and for at least 4 hours after attempted reperfusion. Thirty-five patients were successfully reperfused. In each, the plasma Mb level rose rapidly with peak [Mb] occurring at 111±8.1 (±SEM) minutes after application of therapy. In contrast, Mb levels rose more slowly in the seven patients who were not reperfused, with peak [Mb] occurring 360±61.4 minutes after attempted reperfusion. T25-100 (the time required for [Mb] to rise from 25% to 100% of peak value) was shorter in patients successfully reperfused (71±7.9 minutes) and longer (341±35.3 minutes) in patients in whom therapy was unsuccessful. A rapid rise in [Mb] after successful reperfusion was also evident by a more than 4.6-fold rise in [Mb] over the first 2 hours after reperfusion in all but five patients; in contrast, [Mb] rose by less than 4.6-fold over this same interval in every patient not successfully reperfused (sensitivity, 85%; specificity, 100%; predictive accuracy, 88%). We conclude that a rapid rise in plasma Mb level over the initial 2 hours after attempted reperfusion in acute myocardial infarction provides a useful index of successful reperfusion. (Circulation 1988;78:1352-1357)