Left atrial eccentricity in chronic mitral regurgitation: relation to left atrial function.

AIMS The aim of this study was to assess the changes in the left atrial (LA) shape and to identify the determinants of these changes in chronic mitral regurgitation (MR). METHODS AND RESULTS We enrolled 125 consecutive patients (56 ± 16 years, 51% men) with chronic MR caused by myxomatous mitral valve disease in sinus rhythm and 45 control patients (54 ± 15 years, 55% men) undergoing transthoracic Doppler echocardiography. The LA eccentricity index (LAEi) and the LA volume index (LAVi) were used to estimate the LA shape and size, respectively. There were significant decreases in LAEi (r= -0.723, P< 0.001) and increases in LAVi (r= 0.642, P< 0.001) with increasing severity of MR. In multivariate stepwise linear regression analysis, regurgitant fraction (RF) was an independent determinant of the LAE, whereas RF, left ventricular (LV) mass index and LV diastolic dysfunction grade were independent determinants of the LA volume. The LAEi was positively related to the velocity of A' in the entire population (r = 0.238, P = 0.002). On the receiver operating characteristic (ROC) curve analysis, LAEi ≤1.30 was the best cut-off value to reflect the LA systolic dysfunction (A' velocity <7 cm/s; area under the curve was 0.78, P < 0.001). CONCLUSION LA becomes more spherical with increasing severity of MR, suggesting a decrease in LAE, which is mainly determined by the volume overload. LAE might be closely related to the LA systolic function in chronic MR.