2.3 Fetal echocardiographic and quantitative measurements
Fetal echocardiographic examination was performed with the heart in the
anterior position. The right and left ventricular widths and lengths
were measured at end-diastole in the four-chamber view. We assessed the
appearance of the septum primum and the FO flap in the four-chamber view
as to whether the FO had a restrictive appearance during measurement of
the diameter of the FO at its maximal angle to the attachment point as
defined by previous studies, with a redundant aneurysmal septum primum
bulging ≥50% into the left atrium and flattening the septum, and with a
FO flap swinging at less than 30° into the left
atrium6,7. The inner diameters of the ascending aorta
and main pulmonary artery were measured at systole in the long-axis
sagittal view when the great arteries were in parallel orientation.
Pulse Doppler was used to measure the flow rates of the great arteries
and to assess the direction of blood flow in the DA. In terms of the
constriction of the DA, we measured A peak systolic velocity in the DA
of greater than 1.4 m/s was considered to be in favor of
constriction8. Color Doppler was used to detect VSDs
and measure its diameter both in the four-chamber view and when
visualizing the outlets of the great arteries in the sagittal section of
the heart. All echocardiographic measurements and quantitative findings
were recorded.