Echocardiographic examination
ECG guided, standard two-dimensional transthoracic echocardiographic
studies were performed using available equipments VIVID 7 (General
Electric Company) and IE33 (Philips Company) instruments, with 1.5-4.0
MHz transducer, according to a predetermined protocol recommended by
American Society of Echocardiography and European Association of
Cardiovascular Imaging (EACVI) (3,6,7).
All studies were done with patients lying in the left lateral decubitus
position and breathing quietly. M-mode, 2D (frame rates .50–70 fps),
colour Doppler, PW Doppler, pulsed-wave tissue Doppler, and PW and TDI
(frame rates≥110 s-1) data were obtained in all patients. PW Doppler was
obtained at the left and right ventricle outflow tract and continuous
wave Doppler at the aortic and pulmonary valve. Transmitral flow pattern
with E and A wave velocities was obtained with the sample volume
positioned at mitral leaflet tips. PW TDI was obtained at the septal and
lateral annular ring of the mitral valve, measuring s′, e′and a′ peak
velocities . PW TDI was also obtained at the lateral tricuspid annulus
in the four chamber view. Left atrium (LA) volume was measured from
standard apical 4-chamber views at end-systole just before mitral valve
opening. Left atrial volume index (LAVi) was calculated by dividing LA
volume by body surface area of subjects.
All Doppler echocardiographic images were recorded in a digital raw-data
format (native DICOM format), centralized and sent to core laboratory.
The images were evaluated by three experienced echocardiographers
blinded to any patient data.