Three-dimensional echocardiographic assessment of annular shape changes inthe normal and regurgitant mitral valve

Objectives To compare mitral annular shape and motion throughout the cardia c cycle in patients with normal hearts versus those with functional mitral regurgitation (FMR). Background The causes of mitral regurgitation without valvular disease are unclear, but the condition is associated with changes in annular shape and dynamics. Three-dimensional (3D) imaging provides a more comprehensive view of annular structure and allows accurate reconstructions at high spatial a nd temporal resolution. Methods Nine normal subjects and 8 patients with FMR undergoing surgery und erwent rotationally scanned transesophageal echocardiography. At every vide o frame of 1 sinus beat, the mitral annulus was manually traced and reconst ructed in 3D by Fourier series. Annular projected area, nonplanarity, eccen tricity, perimeter length, and interpeak and intervalley spans were determi ned at 10 time points in systole and 10 points in diastole. Results The mitral annulus in patients with FMR herd a larger area, perimet er, and interpeak span than in normal subjects (P < .001 for all). At mid-s ystole in normal annuli, area and perimeter reach a minimum, nonplanarity i s greatest, and projected shape is least circular. These cyclic variations were not significant in patients with FMR. Annular area change closely para lleled perimeter change in all patients (mean r = 0.96 +/- 0.07). Conclusions FMR is associated with annular dilation and reduced cyclic vari ation in annular shape and area. Normal mitral valve function may depend on normal annular 3D shape and dimensions as well as annular plasticity. Thes e observations may have implications for design and selection of mitral ann ular prostheses.