[Malate dehydrogenase isoenzymes in myocardial infarction].

Plasma CPK activity and the activity of isoenzymes MDH, AST and LDH were assessed in 60 patients with myocardial infarction of different severity, with reference to the time since the onset of the attack. The peaks of CPK and MDH-C activity were reached sooner than those of LDH-M and AST-C, while the CPK and MDH-C curves were similar. The severity of the disease showed correlation to later onset of enzyme peaks and markedly delayed decrease in the respective values. Increased activity of mitochondrial isoenzymes and blood LDH-M provided additional information on the severity of the disease. Delayed normalization of these activities was associated with a poor diagnosis.