[Critical analysis of the radioimmunological methods of determining creatine kinase isoenzyme MB (CK-MB), myoglobin (MG) and of LDH (H4) in ischemic cardiopathy].

We have studied 135 subjects of whom 100 were normal individuals; 10 with diagnosis of acute myocardial infarction (AMI); 10 with angina pectoris; 10 undergoing cardiac catheterism; 5 who underwent open heart surgery. To verify the radioimmunoassay usefulness of CPK cardiac isoenzyme (CK-RIA), of lactate dehydrogenase [LDH (H4)], of myoglobin (MG) in the diagnosis of ischemic disease, we have determined for serum samples: LDH (H4) by radioimmunoassay and HBDH by biochemical assay; CK by biochemical assay; CK-MB by biochemical and radioimmunological assay; MG by radioimmunoassay. The results indicate MG as a sensitive marker for the diagnosis of AMI. In fact serial serum determinations in patients with AMI showed myoglobin levels in 60% of the cases within 1 h after the onset of pain. The CK-RIA is the most sensitive test to evaluate infarct size and LDH (H4) conditioned by the amount of intracellular lactate is an useful test to evaluate myocardial anoxia.