A consecutive series of 41 patients undergoing elective aortic surgery had pre-operative assessment of cardiac function by radionuclide angiocardiography. Their subsequent progress was monitored. There were 4 patients whose pre-operative left ventricular ejection fraction was less than 30 per cent and 3 of these patients died of cardiac failure postoperatively. There was only 1 death from cardiac failure amongst the 37 patients whose pre-operative left ventricular ejection fraction was less than 30 per cent. Radionuclide angiocardiography is an accurate indicator of myocardial function of patients before major aortic surgery.