Echocardiographic examination
Echocardiographic examinations were performed using an Aeroscan CD 25
ultrasound system with a phased-array sector transducer working at
frequencies between 3.6 - 4.5 MHz with a maximum depth of 24 to 26 cm, a
frame rate of 13 to 31 frames/ s and the focus point at 10 to 15 cm to
obtain 2-D, M-mode and Doppler images of the heart, as per the procedure
reported by Schwarzwald (2019).
Echocardiography was performed in right parasternal short-axis view at
the level of the chordae tendinae. Echocardiographic indices including
left ventricular internal diameter during diastole and systole (LVIDd
and LVIDs), left ventricular posterior wall thickness during diastole
and systole (LVPWd and LVPWs), Interventricular septum thickness during
diastole and systole (IVSd and IVSs), end diastole volume (EDV), end
systole volume (ESV), ejection fraction (EF), fractional shortening
(FS), stroke volume (SV), aortic diameter (Ao) and left atrium in three
cardiac cycles and the average values were recorded and compared between
before and after exercise. Color doppler echocardiography
(Gunther-Harrington et al. , 2018) was done1hour before and 5 min
after exercise to identify valvular regurgitation.