Abstract
To investigate the usefulness of lactate dehydrogenase isoenzyme-1 (LD-1) and LD-1/LD ratio for diagnostic assessment of acute myocardial infarction (AMI) in the subacute stage, we studied for one month 20 patients with AMI and another 20 patients with abnormal score of LD-1 and LD-1/LD ratio randomly chosen at our outpatient clinic. Serum levels of cardiac enzymes revealed that LD-1 and LD-1/LD ratio were in the abnormal range from 48 to 168 hours after the onset of AMI. Their positiverate at 360 hours after the onset was 58% and 64%, respectively. Other cardiac enzymes, such as AST, ALT, CK and CK-MB were quickly normalized over 48 hours after onset. The 20 patients with abnormal score of LD-1 and LD-1/LD ratio in the laboratory examination had few cardiac symptoms and normal levels of other cardiac enzymes. The 20 patients, 5 had AMI, 2 angina pectoris, 2 congestive heart failure, 2 pulmonary embolism, 3 abnormal electrocardiogram, 3 malignant tumor, and 3 trauma. One or two weeks had already passed after the onset in the 5 AMI cases. LD-1 and LD-1/LD ratio might provide us with useful information for diagnosis of asymptomatic or subacute phase AMI.
