Enzymatic profile of myocardial infarct.

T he causal relationship between the rise in activity of certain enzymes in the serum and the occurrence of damage to the myocardium has been established without question. Experiments and histochemical investigations have shown that infarcted heart muscle is rapidly depleted of various enzymes, and that these enzymes appear in an active form in the blood that drains from the infarcted myocardium. Rapid clinical utilization of these observations followed the report by LaDue and associates1 in 1954, that serum glutamic oxalacetic transaminase (SGOT) is elevated after an acute myocardial infarct. As indicated in the preamble to this report, many other enzymes have been tested for their applicability in the confirmation of the diagnosis of myocardial infarct. The myocardium is a rich source of enzymes, and, in addition to SGOT, elevations of the malate and lactate dehydrogenases, aldolase, phosphoglucose isomerase, and creatine phosphokinase are usually present after infarction of cardiac muscle. To the present time, however, only five enzymatic assays have withstood critical clinical and laboratory investigation. These