Assessment of Mitral Regurgitation in Dogs by Color Doppler Echocardiography

The purpose of this study was to evaluate the severity of mitral regurgitation (MR) by color Doppler echocardiography, and compare the obtained results with the data of modified New York Heart Association (NYHA) functional classification scheme. The study was performed on 46 dogs (14 female, 32 male) with mitral regurgitation. Their ages ranged 3-14 years, with the mean age was 8.7 years. Two sets of parameters were investigated, including: (1) regurgitant jet area (RJA), left atrial area (LAA) and the ratio of RJA and LAA; (2) proximal width of regurgitant jet (Rw), diameter of mitral annulus (MAD) and the ratio of Rw and MAD. Of these parameters, the best correlation was obtained from RJA/LAA (r = 0.91), determined in the apical plane where the jet was best visualized. With our instrumentation, the ”cutoff” values in dogs separating mild, moderate and severe MR appear to be 25% and 50% for RJA/ LAA. This parameter, therefore, represents a useful method for estimating semiquantitatively the severity of mitral regurgitation by color Doppler echocardiography.