Activities of some enzymes in serum after therapy with intracoronary streptokinase in acute myocardial infarction.

Enzyme kinetics for creatine kinase (CK), CK-MB, aspartate aminotransferase (AST), and lactate dehydrogenase (LD) in serum were followed in 14 patients who had suffered acute myocardial infarction and who were given intracoronary streptokinase shortly (mean 4.9 h, SD 2.6 h) after onset of symptoms. In the 10 patients for whom thrombolysis was successful, CK activity peaked earlier (12.8 vs 21.6 h) and at higher values (3548 vs 2436 U/L) than in the four patients for whom the treatment was unsuccessful. The mean maximum rate of increase in CK was threefold greater in the former group (574 vs 169 U/L per hour), but the total amount of CK released into the circulation and the fractional disappearance rates were similar for both groups. The profiles for AST and CK-MB for successfully treated patients closely resembled those for CK. LD, however, peaked significantly later than CK (25.7 vs 12.8 h). Early peaking of CK or CK-MB after nonsurgical reperfusion can be potentially useful as a noninvasive in vitro index to the success of therapy of myocardial infarction with thrombolytic agents.