Electrocardiographic and enzymatic infarct size in a randomised study of intracoronary streptokinase and intravenous anisoylated plasminogen streptokinase activator complex in acute myocardial infarction.

The effect of thrombolytic therapy on ECG and enzymatic indices, including estimates of relative infarct size, was studied in 93 patients with acute myocardial infarction randomised to intracoronary streptokinase or intravenous anisoylated plasminogen streptokinase activator complex (APSAC) therapy within 6 hours of the onset of symptoms. 90 minutes after treatment, 49% (19/39) of the evaluable streptokinase patients and 44% (19/43) of the APSAC patients had reperfused (p = NS). The time from treatment to reperfusion was less in the streptokinase patients (30 +/- 18 minutes for streptokinase and 42 +/- 22 minutes for APSAC, p less than or equal to 0.02). Resolution of ST segment elevation, 90 minutes after treatment, was greater in the streptokinase patients (residual ST segment elevation 47 +/- 36% of initial value for streptokinase and 70 +/- 49% for APSAC, p less than or equal to 0.06) and in the patients reperfused by either agent (residual ST segment elevation 46 +/- 34% for reperfused and 68 +/- 52% for non-reperfused, p less than or equal to 0.10). ECG infarct size at discharge, determined by sum of Q waves and a 29-point QRS score, relative to the degree of initial ST segment elevation was similar in the streptokinase and APSAC patients, but smaller in reperfused than non-reperfused patients (p less than or equal to 0.01 for sigma Q). Peak serum creatine kinase and MB isoenzyme of creatine kinase levels were similar in the streptokinase and APSAC, and in reperfused and non-reperfused patients. Lower peak lactic acid dehydrogenase and especially lactic acid dehydrogenase isoenzyme values (by 16% and 22%, respectively) were observed in reperfused patients, but differences did not achieve significance. However, the time to peak enzyme levels was significantly shorter in the reperfused patients. Early intracoronary streptokinase and intravenous APSAC therapy have similar effects on ECG and enzymatic infarct size. Reperfusion by either agent, given at a mean of 3 hours 25 minutes, may reduce estimates of infarct size modestly.