Objective To prospectively determine the percentage of cases of acute myocardial infarction (AMI) resulting in sudden death outside the hospital.

Methods Two groups of patients were defined by the emergency medical services. Group A comprised all out-of-hospital sudden deaths in 2004 meeting the criteria for possible or probable AMI (n=395 among 1072 sudden death patients, ie, 37%). Group B comprised all in-hospital AMI in the district during the same year according to hospital registry records (n=731).

Results The out-of-hospital sudden death rate due to AMI was determined by the ratio of the number of patients in group A over the total number of patients (A+B), and was found to be 35% (95% CI 32% to 38%).

Conclusion The estimated mortality of AMI appears to be 35% in this population. This figure suggests that significant improvement in the treatment of out-of-hospital cardiac arrest is still necessary.