Summary: In two patient series including 809 and 327 patients, respectively, with acute myocardial infwtion we have compared those who died in myocardial rupture (verified at autopsy, Group A) with those who died without rupture (autopsied, Group B), and those who survived hospitalization (Group C) with regard to previous history and clinical course in hospital. Rupture among autopsied patients was observed in 45% and 40% of the cases in the respective studies. Previous infarction was observed in each study as 0% and 0% in Group A compared with 25 % and 3 1 % in Group B, and 20 % and 34 % in Group C. Previous angina pectoris was observed in 26 % and 22 % in Group A compared with 50 % and 54 % in Group B and 52 9% and 54 % in Group C. Maximum serum enzyme activity in Group A did not differ from Group B, but was higher than in Group C (p