Serum cyclic 3',5'-nucleotide phosphodiesterase activity in myocardial infarction

The activities of cyclic 3',5'-nucleotide phosphodiesterases which hydrolyze cyclic 3',5'-nucleotides were measured in sera from patients with an acute myocardial infarction, angina pectoris and other heart diseases. Cyclic AMP and cyclic GMP phosphodiesterase activities were significantly elevated in acute myocardial infarction, but not in angina pectoris and other cardiovascular diseases. The peak activity appeared approximately within 24 hours following the acute attack of chest pain, and then gradually decreased as the patient recovered. The observed changes of cyclic 3',5'-nucleotide phosphodiesterase activity were similar to that of the other enzyme activities such as GOT, CPK and LDH in sera of acute myocardial infarction. These data reflect damage of myocardial cells during myocardial infarction.