[Evaluation of infarct size using serum concentration of the CK-MB isoenzyme (author's transl)]

The size of infarction was determined in 21 patients with acute myocardial infarction aged 42 to 76 years using serial analyses of the serum concentrations of the total creatine kinase (CK) and of the CK-MB isoenzyme. CK-MB isoenzyme concentrations reached their maximum in serum three hours earlier on average and returned to the initial value 10 to 12 hours before the total CK. CK-MB isoenzyme concentrations reached a maximum of 12.4% of maximum total CK activity. In 17 uncomplicated cases the infarct weight determined from total CK (40 +/- 23 g) and from CK-MB isoenzyme (35 +/- 23 g) was only different by 5 g (r = 0.92). In 4 patients with infarction and defibrillation or reanimation use of total CK led to an overestimation of the infarct size by more than double. The determination of the infarct size from CK-MB isoenzyme values proves that without extracardial CK release, estimation of the infarct size can also be done sufficiently exactly from the total CK concentrations. In complicated cases, however, the specific myocardial CK isoenzyme makes determination of the infarct size possible