[Fetal screening of congenital heart disease]

Echocardiograms of two hundred and ninety normal fetuses at 18-39 weeks of gestation were studied with a real-time linear scanner (3.5 MHz). Aortic valvular diameter, pulmonary valvular diameter, mitral valvular diameter, tricuspid valvular diameter and total cardiac dimension were measured. These parameters increased with fetal growth. The ratios of pulmonary to aortic valvular diameter and of tricuspid to mitral valvular diameter were more than 1, suggesting right ventricular dominance in the fetal hearts. The cardio-thoracic ratio was about 50% in this period. The four-chamber view, left ventricular long-axis view, ventricular short-axis view, short-axis view of the great arteries, the view of the aortic arch and the view of the inferior and superior vena cava were also recorded. These six views could be obtained in 9.8% of all subjects at the same time. Detection rates for these views were the greatest in pregnancy at 22-33 (especially 28-29) weeks of gestation. The ventricular short-axis view and short-axis view of the great arteries were easily detected in the dorsoposterior position, whereas the view of the aortic arch was obtained in the dorsoanterior position. It was concluded that fetal echocardiography needed to be performed at least twice, at 22-23 and 28-29 weeks of gestation, and this would be useful in diagnosing some congenital heart diseases.