The objective of this study was to evaluate the influence of acute coronary care on the myocardial infarction (MI) case-fatality gradient observed in three French regions. In 1989, a total of 813 hospitalized events of premature MI, occurring in men and women aged 25-64, were registered in three WHO-MONICA sites established in Lille (North of France), Strasbourg (East of France) and Toulouse (South of France). The case-fatality rates observed 28 days after the onset of the MI, were 30.6% in Lille, 17.5% in Strasbourg and 9.9% in Toulouse (P < 0.0001). We compared the management of events and the use of cardiovascular therapies in these centres before admission to hospital, during the stay and on discharge from hospital. Differences were observed between the three centres in the use of medical treatments: in Strasbourg, aspirin and antiplatelet agents were prescribed 15% less frequently, (P < 0.0001) while diuretics were prescribed twice as often as in Toulouse (P < 0.0001). Thrombolytic agents (P < 0.01) and invasive techniques (coronary angiography, coronary angioplasty and coronary bypass surgery) (P < 0.0001) were more widely used in Toulouse compared with the two other centres. Lille might have a higher rate of coronary case fatality than Strasbourg and Toulouse because of a series of cumulative characteristics. The disease presented in a more serious form: more frequent electrocardiographic changes in anterior leads (P < 0.02), higher percentage of use of inotropic drugs in association with diuretic agents (P < 0.04), and longer duration of stay in intensive care units (P < 0.0001). However, when case-fatality rates were adjusted for all these variables in a multivariate model, the rate remained significantly higher in Lille than in the two other centres (P < 0.0001), as suggested by the odds ratio (3.27, 95% confidence interval: 1.69-6.32). In conclusion, the influence of acute coronary care on the MI case-fatality gradient observed between the North and South of France is very weak.