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.