Mitral annular motion as a surrogate for left ventricular ejection fraction: real-time three-dimensional echocardiography and magnetic resonance imaging studies

AIMS: To validate the accuracy of mitral annular motion assessed by real-time three-dimensional echocardiography (RT3DE) as a surrogate for determination of the left ventricular function in comparison with magnetic resonance imaging (MRI). METHODS AND RESULTS: Forty-seven patients with a variety of cardiac pathologies underwent both RT3DE and MRI exams. After 3D data sets were transferred to a PC with a custom-made program, nine consecutive rotational apical plane images (20 degrees apart) were displayed. The two mitral leaflet insertion points were manually identified in each plane. The geometry of the mitral annulus was reconstructed from a total of 18 coordinates (x, y, z), and the changes in mitral annular area and mitral annular motion along the apical long axis were calculated. The left ventricular ejection fraction (LVEF) determined by MRI was 41+/-18%, and 24 patients had LVEF<50%. Mitral annular motion (y) obtained by RT3DE was 11+/-5 mm and correlated moderately well with LVEF (x) measured by MRI (r=0.84, y=0.25x+0.43, p<0.0001). The mitral annular motion<12 mm was a good threshold for detecting LVEF<50% with 96% sensitivity, 85% specificity, and 91% accuracy. CONCLUSION: Mitral annular motion determined by RT3DE correlated moderately well with LVEF; and systolic motion, <12 mm, accurately detected LV dysfunction.