To define the clinical characteristics, prognosis and treatment of myocardial infarction (MI) in the elderly, we retrospectively compared the files of 101 patients aged > or = 75 years (mean: 82 +/- 4 years) and of 120 others aged < or = 65 years (mean: 55 +/- 4.7 years). The figures corresponding to younger patients are presented in brackets. The elderly group included 60.4% women (5%: p < 0.001), 58.9% hypertensive subjects (38.3%: p = 0.005); 30.4% diabetics (11.7%: p = 0.0013) and 12.6% smokers (66.1%: p < 0.001); 20.8% of the elderly had a history of MI (10%: p = 0.002), 15.8% of arteriopathy of the lower limbs (8.3%: p = 0.001) and 6.9% of cerebrovascular accident (1.7%: p = 0.02). Elderly patients were admitted after an average of 26.6 hours (10.4 hours: p < 0.001). Only 56.4% (79.2%) reported typical MI pain, 22.8% (7.5%) had a painless form, 31.8% (4.2%) an initial left ventricular failure, 21.8% (7.5%) a global cardiac dysfunction and 20.8% (4.2%) a cardiogenic shock (p < 0.001 for all comparisons). 63.4% had an anterior MI (40.8%: p < 0.001), 40.6% a Q-form (29.6%: p = NS) and 22.2% an atrial fibrillation (0.8%: p < 0.001). Serum myoglobin and total CK concentrations were significantly lower in elderly subjects. 20.8% of them received beta-blockers (86.7%), 43.6% aspirin (80%), 14.6% oral anticoagulant (56.7%), but 63.4% were given diuretics (25.2%) and 31.7% digitalis alkaloids and positive inotropic drugs (6.7%) (p < 0.001 for all these comparisons). Heparin, nitrates, calcium channel blockers, ACE inhibitors and antiarrhythmics were prescribed as often regardless of age. Only 10 elderly patients (9.9%) were treated with thrombolytics (77: 65%: p < 0.001); 6 (5.9%) underwent coronary angiography (43: 35.8%: p < 0.001), 2 (2%) angioplasty (11: 9.2%) and one (1%) coronary bypass surgery (12: 10%). 35 elderly patients (34.7%) died while in hospital (5: 4.2%), 22 suddenly, 10 in cardiogenic shock and 3 due to arrhythmias. 38 cases (37.8%) of heart failure (21: 17.5%), 21 (20.8%) recurrences of coronary insufficiency (8: 6.7%) and 11 (10.9%) mechanical complications of MI (4: 3.3%) were also observed (p < 0.001 for all these comparisons). Due to lack of sufficient data, we could not define the status of the surviving patients discharged from hospital. The wider use of thrombolytics, angiography and angioplasty (coronary bypass surgery still having a heavy mortality and morbidity) is probably the best way to improve the prognosis of MI in the elderly.