Between 1975 and 1994, we performed 20 pericardiectomies for 19 patients with constrictive pericarditis (CP) through a median sternotomy (13 cases), a left thoracotomy (2 cases), a median sternotomy combined with a left thoracotomy (4 cases) or a median sternotomy under ECC (1 case). One patient died from LOS at 1st POD due to myocardial failure. Pericardiectomy through a median sternotomy decreased RA pressure but PAW pressure did not decrease in some patients. On the contrary, pericardiectomy through either a left thoracotomy or a median sternotomy combined with a left thoracotomy decreased PAW pressure as well as RA pressure significantly. Responses to bicycle exercise demonstrated marked elevation of RA and PAW pressures even in a mild case of CP, so that the exercise testing seems to be useful for early detection of CP and evaluation of the operative results.