The role of serum myoglobin in the detection and measurement of myocardial infarction.

The use of serum myoglobin determinations in the diagnosis and quantitation of acute myocardial infarction was studied in 53 patients. Serial blood samples collected for the first 72 h after pain were analysed for serum myoglobin using a radioimmunoassay procedure. Samples were also assayed for serum creatine kinase (CK) and its myocardial isoenzyme CK-MB, aspartate aminotransferase (AST) and alpha-hydroxybutyrate dehydrogenase (alpha HBDH). Analysis of first and second samples obtained at mean times of 7.6 and 10.7 h respectively after pain produced the following detection rate: serum myoglobin 85% and 98%; serum CK 71% and 85%; serum AST 58% and 81%; serum CK-MB 29% and 60%; serum alpha HBDH 23% and 33% respectively. Total CK-MB and myoglobin release from damaged myocardium were calculated using the method of Norris et al. [16]. A significant correlation was obtained between infarct size calculated from CK-MB and myoglobin in the whole group (n = 29, r = 0.71, p < 0.001). The correlation was even more significant for smaller infarcts with CK-MB release < 220 U/l (n = 13, r = 0.92, p < 0.001).