A comparison of radionuclide methods of evaluating aortic regurgitation with observations on the effect of exercise and symptoms.

The severity of aortic regurgitation, as assessed by the radionuclide regurgitant index and Fourier amplitude ratio, was compared in 29 patients. Both methods were highly reproducible and agreed in patients with mild-to-moderate regurgitation. The regurgitant index fell with exercise. This change showed a linear relationship with heart rate, allowing the regurgitant index to be corrected for heart rate. There was general agreement between the radionuclide method and echocardiography, but the regurgitant index was unable to select patients with symptoms. The regurgitant index provides an overall guide to the severity of aortic regurgitation, but may be unreliable in the presence of deteriorating ventricular function.