As for myocardial infarction, the epidemiology of acute coronary syndromes is very different according to whether it concerns hospitalized patients only or acute coronary syndromes as a whole: many patients die before any medical intervention. The epidemiology of acute coronary syndromes is not well known since we have almost no specific data regarding unstable angina. The annual incidence of acute coronary syndromes in France is greater than 280 per 100,000 men and 60 per 100,000 women. The 1-month lethality rate is about 50%, increasing sharply with age.