ECHOCARDIOGRAPHY
A one lead electrocardiogram was recorded continuously during the TTE and TEE (informed written consent was taken from all patients before TEE). Two-dimensional and Doppler echocardiographic studies were performed in the left lateral decubitus position in conventional views (parasternal long, short-axis, and apical two and four-chamber view) according to American Society of Echocardiography guidelines.11 All patients were evaluated using two-dimensional M-mode, pulsed- and continuous-wave Doppler echocardiography. The mitral valve area (MVA) was calculated using planimetry and pressure half-time methods. The maximum and mean pressures gradients across the valve were measured by continuous-wave Doppler from the apical four-chamber view. The left ventricular end-diastolic and end-systolic diameters, interventricular septum and posterior wall thickness, left ventricular ejection fraction and left atrial diameter (LAD) were recorded from the parasternal long-axis view. Modified parasternal short-axis view [as described by Herzog et al12 ] was used to visualize the left atrial appendage.
Tissue Doppler imaging (TDI) :
This was performed in the apical four chamber view, with probe placed in the lateral annulus. A Doppler velocity range of (-20 to 20) cm/sec was selected. The three major velocities were recorded: one positive systolic velocity (Sa-wave) and the two negative diastolic velocities (E- and A-waves). The peak systolic and diastolic velocities were measured at a sweep speed of 50 mm/sec.