Background – We investigated the usefulness of Doppler echocardiography and tissue Doppler imaging for the estimation of LV filling pressure in patients with chronic severe mitral regurgitation (MR). Methods – We prospectively enrolled 34 patients (20 patients were men, age 54짹14 years) with chronic severe MR. Mean left ventricular (LV) ejection fraction was 61짹7% and regurgitant fraction was 64.5짹14.5 %. LV end-diastolic volume was 245.2짹74.2 ml. 12 patients (35%) were in atrial fibrillation. Comprehensive echocardiographic examination including tissue Doppler imaging was performed. In all patients, LV pressure was obtained invasively with micromanometer-tipped catheter and mean LV diastolic pressure (M-LVDP) was measured. Results- In all, early mitral inflow velocity (E) (r = 0.406, P = 0.017) and the ratio of mitral velocity to early diastolic mitral annular velocity (E/E���) (r = 0.409, P = 0.016) showed a good correlation with M-LVDP. In particular, patients with normal sinus rhythm (n=22) showed better correlation between E/E��� and M-LVDP (r = 0.628, P = 0.002) (Figure). E/E��� > 14 showed 90% of sensitivity and 67% of specificity for predicting elevated M-LVDP (>12mmHg). Conclusions - E/E��� ratio is a reliable estimate of LV filling pressure in the presence of severe mitral regurgitation in patients with normal sinus rhythm.