title: Changes in the ratio of lactate dehydrogenase isoenzymes 1 and 2 during the first day after acute myocardial infarction.
abstract: It is known that the ratio of isoenzyme 1 to total lactate dehydrogenase (LD, EC 1.1.1.27) in serum is increased in all patients with acute myocardial infarction within 24 h of the infarct. We now show that the LD-1/LD-2 ratio for serum more promptly indicates acute myocardial infarction, being for most patients equivalent to measurement of creatine kinase (EC 2.7.3.2) isoenzyme 2 (CK-2, CK-MB) in serum. Of 128 patients with a confirmed diagnosis of myocardial infarction, 66 had normal values for all "cardiac" enzymes at the time of admission, but greater than 75% of them showed a parallel increase in values for CK-2 and the LD-1/LD-2 ratio. Of the 26 patients who had one or more abnormal values for cardiac enzymes on admission, 95% showed a parallel increase in CK-2 and the LD-1/LD-2 ratio, the median time for the beginning of these changes being 9 h from the onset of chest pain. The remaining 36 patients were excluded from the study because CK-2 decreased after admission or because the time of onset of chest pain was uncertain.
mesh_terms: D000328:Adult; D000368:Aged; D003402:Creatine Kinase / Q000097:blood; D004587:Electrophoresis, Agar Gel; D005260:Female; D006801:Humans; D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000201:enzymology*; D013997:Time Factors
chemical_list: D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase; D003402:Creatine Kinase