Diagnosis of myocardial infarction by serum isoenzyme analysis.

Serial monitoring of the serum isoenzyme patterns of creatine phosphokinase (CPK) and lactate dehydrogenase (LDH) in patients suspected of acute myocardial infarction has become a highly sensitive and specific diagnostic method. The predictable evolution of isoenzyme patterns following infarction permits diagnosis and recognition of early stages, recovery stages and extension of infarction in the individual. Usual therapeutic and resuscitative manipulations do not interfere with evaluation of patients with angina or following cardiopulmonary arrest without infarction. Despite significant elevations of serum enzyme levels following general and cardiac operative procedures, the occurrence of myocardial necrosis in the surgical population can be recognized by detection of the specific CPK-MB isoenzyme.