In 222 patients with coronary heart disease hemodynamics at rest and during exercise were measured before and after aortocoronary bypass surgery. A total of 552 grafts were constructed, i.e. an average of 2.47 grafts per patient. Only 10.8% of the patients had a 1-vessel-disease, 59.2% had a 3-vessel-disease. 10.8% of the patients were provided with one graft, 49.7% got 3 or 4 grafts. In 92.8% of the patients the r. desc. ant. was significantly stenosed, and in 94.2% this vessel has been provided with a graft. Preoperatively only 7 patients had no angina pectoris during exercise (bicycle ergometer in supine position, each load lasting 6 min), postoperatively 154 patients have been completely free of angina pectoris. The preoperative angina pectoris-free exercise tolerance was 27.4 +/- 27.4 W (means +/- SD), postoperatively it was 76.5 +/- 33.8 W. The largest increase of exercise tolerance was observed in patients with a 3-vessel-disease (208%). Preoperatively only 10.1% had normal values of pulmonary wedge pressure and cardiac output at rest and during exercise, postooperatively 51.5%. The postoperative normalization of hemodynamics depends on the number of vessels involved (1-vessel-disease 86%, 3-vessel-disease 39.8% normalization) and on the status of the left ventricle (without a previous transmural myocardial infarction 68.4%; with a previous myocardial infarction 41.0%). The effects of revascularization on myocardial ischemia can be evaluated by measurements of pulmonary wedge pressure and cardiac output at rest and during exercise.