Noninvasive evaluation of the influence of aortic wave reflection on left ventricular ejection during auxotonic contraction

To develop a noninvasive method for evaluating the influence of aortic wave reflection on left ventricular ejection, the carotid pulse wave and the pulsed Doppler wave in the left ventricular outflow tract were evaluated in 35 patients. Agreement between the pulsed Doppler waveform and the aortic flow velocity contour (obtained invasively) was verified by Fourier analysis. The carotid augmentation index was used to determine the magnitude of the aortic pressure wave reflection. A Doppler index named “DR1/3” was defined as the ratio of deceleration at the first one-third in the deceleration phase to the peak flow velocity of the pulsed Doppler. This index was validated by close correlation with the carotid augmentation index (n = 48,r = 0.70,P < 0.01). Both nitrates and nifedipine induced a significant decrease in DR1/3 (indicating an increase in left ventricular ejection flow) in relation to a reduction of the reflected pressure wave. The new noninvasive index, DR1/3, is useful in evaluating the influence of aortic wave reflection as part of the left ventricular afterload and in assessing the benefit of treatment aimed at reducing wave reflection.