One hundred one patients with asymptomatic chronic severe aortic regurgitation and normal ejection fraction were monitored for up to 10 years (mean 55.4 +/- 33.5 months). Predefined surgical indications were the development of cardiac symptoms or the documentation of impaired basal left ventricular function. During the follow-up period there were no cardiac deaths; 14 patients needed surgery, 8 because of development of symptoms and 6 because of left ventricular impairment. The risk of surgery was 12% at 5 years and 24% at 10 years. Baseline end-systolic diameter > 50 mm and radionuclide ejection fraction < 60% were independent predictors or either cardiac symptoms or left ventricular dysfunction. In patients needing surgery, a pattern of progressive left ventricular dilatation was demonstrated. There were no deaths during surgery, and echocardiographic and radionuclide parameters normalized in the first year of follow-up. Our data confirm that the prognosis of severe aortic regurgitation in patients with no symptoms is good and that the occurrence of asymptomatic left ventricular dysfunction is an uncommon event. Surgery can be safely postponed until the appearance of cardiac symptoms or the documentation of left ventricular dysfunction at rest.