Abstract

Objectives: We sought to evaluate the three-dimensional (3D) features of functional mitral regurgitation (FMR) and their geometric determinants by real-time 3D colour Doppler echocardiography.

Methods: Real-time 3D colour Doppler echocardiography was performed in 52 patients with severe left ventricular dysfunction. With aliasing velocity set around 40 cm/s, proximal isovelocity surface area (PISA) radius was measured on medial, central and lateral antero-posterior planes at a mid-systole frame, and the largest (PISAmax) was determined. Geometric investigations of the left ventricle and mitral valve were performed.

Results: The distal length from the anterior leaflet angulation on the central plane was significantly longer in the 29 patients (56%) with eccentric PISA than in the 23 patients with central PISA (1.73 (0.44) vs 1.47 (0.33) cm, p<0.05). The 18 patients (35%) with both-sides dominant PISA had a smaller anterior leaflet bending angle (141° (8°) vs 147° (8°), p<0.05) and a longer distal length from the angulation on the central plane (1.80 (0.36) vs 1.51 (0.41) cm, p<0.05) than the remaining 34 patients. The 14 patients (27%) with separate PISAs had smaller PISAmax (0.33 (0.13) vs 0.45 (0.16) cm, p<0.05), and tenting height (0.91 (0.20) vs 1.06 (0.24) cm, p<0.05) and tenting area (2.1 (0.6) vs 2.7 (0.8) cm², p<0.05) on the central plane than in those with single PISA.

Conclusions: 3D features of FMR are quite diverse. The shape and site of anterior leaflet bending determine the shape of the regurgitant orifice, and small mitral valve tenting generates separate small regurgitant orifices of FMR in patients with severe left ventricular dysfunction.