Nowadays, the majority of patients undergoing aortocoronary bypass surgery have a history of myocardial infarction. In our first series of 1000 patients operated between 1973 and 1979, about two thirds of the patients had suffered myocardial infarction; about 80% of them within the previous three months. The method most frequently used to select post-infarction patients for coronary angiography is a simple exercise test. The post-infarction period in the context of this symposium was defined as the first 12 weeks after infarction. As far as exercise tests are concerned, we may divide this period into three subperiods: the very early post-infarction period, especially the first week after infarction. Exercise testing does not play a role in this very early period; the second period is the time of an early post-infarction exercise test or the predischarge exercise test (second and third week); from the fourth to the twelfth week in many European countries, rehabilitation measures will follow, usually in a special institution. This is the time of what we will call in short 'the late post-infarction exercise test'.