Discussion
In general Pulmonary Atresia (PA) cases reveal various sizes of right ventricles ranging from a very small to enlarged ones (underdeveloped (80%), normal (6,5%) or enlarged (13%) [1]. Hypoplastic right ventricle caused by PA is associated with presence of small tricuspid valve, usually without regurgitation. In these cases, coronary arterial communications are very common findings. In contrary, such communications are not found in cases with enlarged right ventricles, but here tricuspid regurgitations are quite common [2].
When pulmonary valve atresia is detected, the presence of a fistula should always be taken into account [3]. The earliest diagnosis of this condition was reported by Chaoui et al. [3] in a 13-week fetus. As Chaoui et al. state, the primary etiological factor could be the fistula itself, where deviation of the right ventricular outflow, causes the perfusion in the pulmonary valve to be reduced, thus leading to PA. After some authors, in our opinion all the cases with enlarged NT with normal karyotype has to undergo early first trimester fetal echocardiography, which has to exclude most of CHDs [5].
A video beneath demonstrates our case: 11 weeks fetal heart in adjusted Tomographic Ultrasound Imaging (lower quadrants show 5C and 4C views, upper right 3VT view)
Video 15: