Doppler echocardiography:
Standard ultrasound scanners (Philips iE33; Philips Medical Systems, Andover, MA, USA; GE Vivid E9, GE Healthcare, Milwaukee, WI, USA) with a 3.5 MHz transducer, including tissue Doppler imaging (TDI) was used for transthoracic Doppler echocardiography and strain echocardiography was conducted using a speckle tracking software. Both conventional M-mode and 2D echocardiography were performed from the left parasternal and apical window. Each measurement was taken carefully after examining patients in both supine and left lateral positions. During the end-systole and end-diastole, M-mode LV readings were acquired. LV EF was calculated with LV volume measurements taken in biplane projection from apical two-chamber and four-chamber views. Using the end-diastolic values of septal and posterior wall thickness and LV cavity dimension, LV mass was determined as per the cube formula. Bi-apical Simpson rule was applied to compute LV volumes and the simplified Bernoulli equation to calculate the tricuspid pressure gradient.