Surgical indication in symptomatic patients with chronic aortic regurgitation is mandatory, but it is sometimes doubtful in two extreme situations: asymptomatic patients and patients with severe left ventricular dysfunction. The authors review the contribution of radionuclide angiography (RNA) for the selection of surgical indication in these two groups of patients, by the evaluation of baseline ejection fraction and of contractile reserve, defined as ejection fraction variation with exercise in asymptomatic patients and with inotropic stimulation in patients with severe left ventricular dysfunction. In asymptomatic patients, RNA may contribute to the selection of patients with incipient ventricular dysfunction (manifested only with exercise), in which a closer follow-up should be obtained, to propose surgery early when baseline ventricular dysfunction appears. In patients with severe ventricular dysfunction, RNA may give us some clues on the probability of left ventricular function recovery after surgery, contribution to the decision of proposing conventional surgery or heart transplant. The authors shortly review preliminary data on the follow-up of 48 patients with chronic aortic regurgitation, studied by RNA with exercise (44 patients) or dobutamine infusion (4 patients) at the Hospital de Santa Cruz from 1987 to 1991. Fifteen of these patients have been submitted to surgery.