| Abstract: | The Doppler method by permitting assessment of transvalvular blood flow velocity has provided a direct means to interrogate aortic regurgitant flow. Pulsed Doppler permits detection of disturbed diastolic flow by sampling proximal to the aortic valve in the outflow tract and is highly sensitive for diagnosis of aortic regurgitation (AR). For semi-quantitative assessment of the severity, left ventricular (LV) mapping can be performed and a ratio of the area of retrograde diastolic to antegrade systolic flow in the descending aorta can be used. According to the continuity principle, it should be possible to estimate regurgitant fraction by examination of forward flows from two different sites, one representative of forward output and one of total left ventricular output, but this method has not yet been sufficiently validated. Continuous wave (CW) Doppler is nearly as sensitive for detection of aortic regurgitation as pulsed wave (PW) Doppler. Signal strength of regurgitant jet provides an indirect clue to its severity: generally a strong signal indicates moderate to severe degree, a weak signal is associated with mild degrees of regurgitation. The spectral outline of regurgitant jet velocity is determined by instantaneous pressure difference between aortic root and the left ventricle during diastole and an indirect clue to severity of aortic regurgitation is provided by the slope of the curve. A steeper slope or shorter velocity half-time is associated with more severe degrees of regurgitation and vice versa. However, there is considerable scatter in this correlation for any given grade of severity of aortic regurgitation, providing a limited predictive value.(ABSTRACT TRUNCATED AT 250 WORDS) |
