Association of Relatively Short Posterior Mitral Leaflet With Mitral Regurgitation in Patients With Atrial Fibrillation

Background: The underlying mechanism of mitral regurgitation (MR) in atrial fibrillation (AF) is an isolated annulus dilation caused by left atrial (LA) remodeling. However, the association of mitral valve (MV) geometry with MR in AF patients remains unclear. Methods and Results: We studied 96 AF patients with preserved left ventricular ejection fraction (LVEF). MV geometry was evaluated with 3-dimensional transesophageal echocardiography (3D-TEE). Mitral annulus area of the MR group (n=11, >= moderate) was significantly larger (10.6 +/- 1.8 vs. 8.2 +/- 1.5 cm(2), P<0.0001), and relative posterior mitral leaflet (PML) area (PML area / mitral annulus area) was significantly smaller (0.51 +/- 0.06 vs. 0.57 +/- 0.01, P=0.002) than in the non-MR group (n=85, <moderate). Multivariate logistic regression analysis showed that, in addition to LA volume index (LAVI), a relative PML area was independently associated with MR. For sequential logistic regression models to determine the association of MR, clinical variables including age, gender and LVEF were improved by the addition of LAVI (P<0.001) and was improved by addition of mitral annulus area (P=0.01), and further improved by addition of relative PML area (P<0.001). Conclusions: A relatively short PML plays an important role in the development of MR in AF patients. Assessment of MV geometry by 3D-TEE may thus have clinical implications for better surgical management of AF patients with significant MR.