Pre- and postoperative left ventricular (LV) mass and myocardial contractile state were evaluated in 62 patients with aortic regurgitation (AR) and in 20 patients with aortic stenosis (AS). Preoperatively, there was a significant inverse correlation between LV mass and end-systolic wall stress (ESS)/end-systolic volume index in AR patients and AS patients. In patients with preoperative LV mass exceeding 250 g/m2, ejection fraction failed to return to normal postoperatively, despite reduction in ESS close to the normal controls. Our results indicated that myocardial funtion was irreversible even in postoperative unloading conditions, when preoperative LV mass exceeded 250 g/m2 in AR patients as well as AS patients.