[Value of serial enzyme and isoenzyme tests in early diagnosis of myocardial infarct].

Serial tests for the activity of creatine phosphokinase (CPK), specific cardiac isoenzyme MB CPK, lactic dehydrogenase (LDH) and its fractions LDH1 and LDH2 were conducted in 55 patients with myocardial infarction. The control group consisted of 15 healthy persons. It was found that an increase in total CPK activity allows the diagnosis of myocardial infarction to be confirmed in the first hours after the onset of the disease, while simultaneous increase in the activity of MB CPK makes the diagnosis authentic, which is particularly valuable in cases with an atypical course of the disease. A recurrent course of myocardial infarction is attended with parallel changes in the activity of total CPK and its MV fraction. Increased total CPK activity may be due both to myocardial infarction and to extracardiac causes.