[The diagnostic value of CK-isoenzymes in suspected acute myocardial infarction (author's transl)].

CK-isoenzymes were measured in 31 patients hospitalised for suspected myocardial infarctions who had an increase in serum creatine kinase (CK) above 50 U/l. Of 26 patients with definite evidence of myocardial infarction, MB-isoenzyme--specific for myocardial necrosis--was demonstrated in 24. MB-isoenzyme was no longer detectable in two patients hospitalised 48 hours after the onset of symptoms. In the remaining five patients only MM-isoenzyme was found, the elevated CK activity in three patients having been due to an intramuscular injection, and in two others due to pulmonary embolism. Measurement of CK isoenzymes proved of great diagnostic value in three patients with sudden circulatory arrest of, at first, unknown cause after successful resuscitation. Acute myocardial infarction was proven by the presence of MB-isoenzyme. In one of these patients an additional BB-isoenzyme was seen, possibly due to concomitant cerebral ischaemia. In all other patients (with angina, after cardioversion, or after major surgical operations) only MM-isoenzyme was detected. MB-CK-isoenzyme was found to be a highly specific, as well as sensitive, indicator of myocardial necrosis. This being a rather difficult method, its use is not justified in the routine diagnosis, but in doubtful instances its value can hardly be overestimated.