Fetal Echocardiography:
Measurements were performed using the Voluson S10 (GE Medical Systems)
ultrasonography device with a 3.5 MHz convex transducer (6C1-PVT-375BT)
transabdominal probe by the same experienced maternal fetal medicine
specialist. To avoid variations, the three clearest waveforms with the
normal range of fetal heart rate were obtained and averaged. The
two-dimensional (2D) and M-mode imaging of apical four-chamber and
parasternal long axis view at the end-diastol was used for fetal heart
rate (FHR), left ventricle posterior wall thickness (LVPWd), septum
thickness (IVSd), right and left ventricular end-diastolic dimensions
(RVEDD, LVEDD), mitral and tricuspid annular plane systolic excursion
(MAPSE, TAPSE) measurements. Mitral and tricuspid peak early ventricular
filling (E) wave velocity, maximum active atrial filling (A) wave
velocity (cm/s) E wave deceleration time (msn) of mitral and tricuspid
valve (MEDT, TEDT), max peak velocity of aortic (AV) and pulmonary
valves (PV) obtained from pulsed wave doppler imaging (PW). Tissue
doppler imaging (TDI) measurements were performed on the basal septum
and on the lateral walls of right and left ventricle. TDI parameters the
maximal systolic myocardial velocity (Sm), early and
late diastolic myocardial velocities (Em,
Am waves), isovolumic relaxation time (IVRT), isovolumic
contraction time (IVCT), ejection time (ET) of the walls are measured.
Myocardial performance index (MPI, Tei index) was calculated according
to the formula (IVCT+IVRT)/ET).