title: Diagnosis of acute myocardial infarction by detection of circulating cardiac myosin light chains.
abstract: A radioimmunoassay for human cardiac myosin light chains (CM-LC) was developed and evaluated as a selective diagnostic test for acute myocardial infarction (AMI). The assay had a sensitivity of 1.0 ng/ml (+/- 2 standard deviations) in serum. Eighty-three patients with confirmed AMI all showed an elevated plasma concentration of CM-LC at some time during the course of their illness. Of 9 patients from whom early blood samples were obtained, 7 had diagnostic concentrations within 6 hours from the onset of chest pain. Only 2 had an elevated total creatine kinase level at this time. CM-LC concentrations peaked on days 2 to 4, but remained elevated in patients with large AMIs for more than 1 week. In preinfarction syndrome, 8 of 15 patients had elevated CM-LC levels at least once. Of 15 patients with stable angina pectoris, only 1 patient, who had congestive heart failure, showed elevated light chain levels. CM-LC levels were not detectable by this method in the sera of healthy persons (n = 72), patients with recent intramuscular injection (n = 3), or those with a variety of systemic illnesses (n = 14). In initial studies using an antiserum having 25% cross-reactivity between cardiac and skeletal muscle myosin light chains, 3 patients who had extensive skeletal muscle damage appeared to have elevated concentrations. Patients with this finding have not yet been examined with a more specific antiserum (8% cross-reactivity).(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000328:Adult; D000789:Angina, Unstable / Q000097:blood / Q000201:enzymology; D003402:Creatine Kinase / Q000097:blood; D005260:Female; D006801:Humans; D007106:Immune Sera; D007527:Isoenzymes; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000201:enzymology; D009218:Myosins / Q000097:blood*; D011863:Radioimmunoassay
chemical_list: D007106:Immune Sera; D007527:Isoenzymes; D003402:Creatine Kinase; D009218:Myosins