[Continuous wave Doppler echocardiography as a noninvasive evaluation of aortic regurgitation]

Continuous wave Doppler echocardiography permits measurement of high blood flow velocity, which is not obtained by conventional pulsed Doppler echocardiography. In this study, continuous wave Doppler echocardiography was used to measure aortic regurgitant flow velocity, and the utility of this method in evaluating aortic regurgitation (AR) was examined. Continuous wave Doppler recordings of the left ventricular outflow were obtained with the guidance of the long-axis two-dimensional echocardiogram from the apex in 20 patients with AR and 10 without AR. In 18 of the 20 patients with AR, Doppler signals of regurgitant flow were successfully detected. The recorded regurgitant flow velocity pattern had characteristic contours: the regurgitant flow was greater than 1.8 m/sec in velocity immediately after aortic valve closure, and gradually decelerated until the next ventricular systole. The Doppler half time index, which was the time profile to decline to 0.5 of the peak velocity, was significantly shortened in accordance with the degree of AR (p less than 0.01). Thus, continuous wave Doppler echocardiography is a simple, useful method for the noninvasive evaluation of AR.