Using digital subtraction angiocardiography left ventricular (LV) function and mean pulmonary artery pressure (PPA) at rest and during exercise were examined in 49 patients with aortic valve disease, 23 patients with aortic stenosis (AS), 12 patients with combined aortic valve lesions (kAV) and 14 patients with aortic regurgitation (AI). Muscular hypertrophy was present in all patients. LV-mass-to-volume ratio was significantly higher in patients with AS and kAV than in patients with AI. There was no significant difference in heart rate at rest or during exercise among the three groups. During exercise PPA increased significantly in all groups. The increase was significantly higher in patients with AS than in those with AI. End-diastolic and end-systolic volumes increased significantly in patients with AS and kAV on the average, showing no change in patients with AI. Ejection fraction decreased significantly in patients with AS and kAV and remained unchanged in patients with AI. Due to the increase in heart rate cardiac index increased significantly during exercise in all groups. In patients with pressure overloaded left ventricles (AS and kAV) the increase in filling pressure partly results in a decrease of compliance caused by hypertrophy. Thus in these ventricles LV function cannot be judged by LV filling pressures alone. In those patients in whom the indication for valve replacement was given without knowing the results of the exercise test, the changes of LV volumes and ejection fraction were abnormal during exercise on the average.(ABSTRACT TRUNCATED AT 250 WORDS)