Quantification of mitral regurgitation with amplitude-weighted mean velocity from continuous wave Doppler spectra

Amplitude-weighted mean velocity from continuous wave (CW) Doppler spectra was used to measure aortic flow (QAo) and left ventricular mitral inflow (QLVin). These flows were used to quantify mitral regurgitation fraction: RFm = (QLVin-QAo).QLVin-1.100(%).QLVin was calculated from the diastolic time integral of amplitude-weighted mean velocity that was derived from CW spectra with the transducer placed in the apical window and the CW beam directed toward the left ventricular inflow tract. QAo was obtained from the systolic time integral of amplitude-weighted mean velocity by using the same apical window and directing the CW beam toward the left ventricular outflow tract. In 20 normal subjects, RFm ranged between -6.2% and +8% (mean, -0.8%). In 25 patients with pure mitral regurgitation, RFm obtained by Doppler (y) was compared with RFm calculated from biplane left ventriculography and the Fick method (x). The correlation was r = 0.96, SEE = 6.1% of the mean or 12% of the angio-Fick mean; the regression line was y = 0.96x + 0.18; mean y = 49%, mean x = 51%. It is concluded that RFm can be determined accurately by using amplitude-weight mean velocities from CW Doppler spectra. The advantages of this method are its independence from the measurement of the left ventricular inflow or outflow tract area.