Accumulated creatine phosphokinase (ACPK) in 25 patients with acute transmural myocardial infarction (MI) was evaluated as a prognostic criterion of clinical severity of the disease. It has been shown that ACPK values above 2.5U/ml are observed in 91.7% in MI complicated by pump failure. This does not apply to repeated MI. The possibility of mathematical estimation of the course of CPK release was also verified. The contribution of this method for the clinician is discussed.