RT Journal Article SR Electronic T1 Transient neonatal tricuspid regurgitation: a Doppler echocardiographic study of three cases. JF British Heart Journal JO Heart FD BMJ Publishing Group Ltd and British Cardiovascular Society SP 446 OP 451 DO 10.1136/hrt.60.5.446 VO 60 IS 5 A1 M Gewillig A1 M Dumoulin A1 L G Van der Hauwaert YR 1988 UL http://heart.bmj.com/content/60/5/446.abstract AB Three patients with normal hearts and no pulmonary abnormality had neonatal tricuspid regurgitation causing cardiorespiratory distress and cyanosis. The signs of tricuspid regurgitation resolved over a few weeks. In the acute phase echocardiography showed gross dilatation of the right atrium and ventricle. The interatrial septum bulged into the left atrium during the whole cardiac cycle. Doppler echocardiography showed clinically significant tricuspid regurgitation, a right to left shunt through the foramen ovale, reduced flow through the pulmonary valve, and in two patients ductal flow into the pulmonary artery. In one patient tricuspid regurgitation was so great that it impeded the opening of the pulmonary valve and produced functional "atresia" of the pulmonary valve. The presence of regurgitant blood flow through the pulmonary valve showed that the "atresia" was functional rather than organic. Doppler echocardiographic study is useful in distinguishing functional neonatal tricuspid regurgitation from structural abnormality of the tricuspid valve.