Myoglobin, creatine kinase and its isoenzyme MB in serum after acute myocardial infarction.

Serum creatine kinase, creatine kinase MB and myoglobin were determined in patients suffering from acute myocardial infarction (AMI) with shorter duration of symptoms than 6 h. At admission 83% had increased concentrations of myoglobin while 28% had creatine-kinase value above the reference limit. After onset of symptoms peak levels were found after 9.4 h (myoglobin) and 23.0 h (creatine kinase). Maximal levels of myoglobin and creatine kinase divided by upper reference limits correlated and were approximately of the same sensitivity. Compared to myoglobin, there was no difference in behavior between creatine kinase and its isoenzyme. In conclusion the study demonstrates myoglobin to be an early and sensitive indication of AMI.