The value of rest and exercise radionuclide ventriculography as compared to echocardiography and angiography in the detection of left ventricular dysfunction in patients with chronic aortic regurgitation.

Symptomatic patients with chronic aortic regurgitation and a left ventricular ejection fraction greater than 0.50, or forward cardiac index greater than 2.5 l/min/m2 at rest, have a much better survival rate than those with a depressed ejection fraction or cardiac index following aortic valve replacement. The annual mortality rate is approximately 2% for those with well preserved ventricular function versus 10% for those with depressed ventricular function at rest. This is in striking contrast to the situation that exists in patients with aortic stenosis, where the long-term survival is similar for those with a normal or depressed left ventricular ejection fraction or cardiac index at rest. Therefore, it would seem to be important to detect incipient left ventricular failure in patients with chronic aortic regurgitation and to intervene surgically before the left ventricular dysfunction becomes irreversible. In patients with a normal left ventricular ejection fraction at rest, maximal supine bicycle exercise testing with radionuclide ventriculography defines a group of patients with truly normal ventricular function (ejection fraction increases by greater than 0.05 ejection fraction units at peak exercise), and a group with incipient left ventricular dysfunction earlier than previously described variables (i.e., left ventricular ejection fraction at rest less than 0.50, left ventricular end-systolic volume index greater than 90 ml/m2, left ventricular end-systolic dimension greater than or equal to 5.5 cm, left ventricular shortening fraction less than or equal to 25%), and generally before the onset of symptoms.