85 patients with acute myocardial infarction (AMI) have been studied retrospectively. 25 of them died within the 40th day after admission. Serum CK release during AMI can be described by the logistic equation: (formula: see text). We have evaluated for each patient both the final infarct size (calculated at the time of maximal enzyme activity: Tmax) and the initial one (calculated at the inflection time of the curve: Tflex). The total enzyme release in 1 ml of blood has been considered as an indirect index of infarct size. Our results show a good correlation between the initial and the final infarct size. We have considered as limits between survivors and non-survivors the following values: 2.2 IU/ml and 0.6 IU/ml for total CK release at Tmax and at Tflex respectively. The percentage of mortality in those groups is very similar (69% and 75%). However only 38% of non-survivors shows higher values than both 2.2 IU/ml and 0.6 IU/ml. The calculation of infarct size at Tflex allows an early identification of the high risk patients
