Enhanced early mitral flow and reduced systolic pulmonary vein flow may be caused both by increased left ventricular pressure as the result of diastolic dysfunction and by increased transmitral flow as the result of mitral regurgitation. Nevertheless, Doppler parameters are widely used to predict left ventricular filling pressure. We aimed to analyze the interference of mitral regurgitation with Doppler parameters usually used to estimate left ventricular filling pressure and to identify markers independent of mitral regurgitation, which could reliably estimate increased left ventricular filling pressure. Eighty-four patients (age, 62 +/- 9 years; 82% men) had a complete echocardiographic Doppler examination. Transmitral E- and A-wave velocity, E deceleration time and A duration, pulmonary vein systolic and diastolic velocities, and reversal flow duration and maximal and minimal left atrial volumes were measured. The difference between the duration of pulmonary vein and mitral A waves was calculated (A'-A). Mitral regurgitant volume was quantitatively assessed by echocardiography. Left ventricular end-diastolic pressure was measured invasively. Patients had a wide range of left ventricular ejection fraction (14% to 70%), mitral regurgitant volume (0 to 94 mL), and left ventricular end-diastolic pressure (3 to 37 mm Hg). E velocity, E/A, pulmonary vein systolic and diastolic, and systo-diastolic ratios were significantly and independently correlated with both left ventricular end-diastolic pressure and mitral regurgitant volume. A'-A showed a strong correlation with left ventricular end-diastolic pressure (r = 0.70; P <.0001), but the relation with mitral regurgitant volume was not significant (r = 0.19; P =.08). Mitral regurgitation affects the majority of Doppler parameters widely used to predict filling pressure but does not influence Ad'-Ad, which proved to be the strongest predictor of left ventricular end-diastolic pressure.