Conventional echocardiographic and myocardial tissue Doppler measurement: Echocardiography will be performed immediately after LV filling pressure measurements. LV ejection fraction is calculated using Simpson's method for biplane images. Mitral inflow is assessed by pulsed-wave Doppler echocardiography form the apical 4-chamber view. From the mitral inflow profile, the E-wave velocity, A-wave velocity, and E-deceleration time are measured. Pulsed-wave tissue Doppler imaging (TDI) is performed using spectral pulsed Doppler signal filters, by adjusting the Nyquist limit to 15 - 20 cm/s and using the minimum optimal gain. In the apical 4-chamber view, a 3-mm, a pulsed-wave Doppler sample volume is placed at the level of the mitral annulus over the septal border. Pulsed-wave TDI results are characterized by a myocardial systolic wave (S') and 2 diastolic waves: early (E') and atrial contraction (A'). The pulsed-wave TDI tracing is recorded over 5 cardiac cycles at a sweep speed of 100 mm/s and is used for offline calculations.