An experimental procedure called fetal balloon atrial septostomy can be used to artificially create the required defect in utero.

[2] This usually causes the foramen ovale to remain open after birth, leading to atrial septal defect.

[4] As there is no communication between the right atrium and the right ventricle, there must be an atrial septal defect to allow blood to flow into the left cardiac chambers.

If evidence of a congenital heart disease is found, the diagnosis can be confirmed by a foetal echocardiogram.

The definitive investigation is, as in all congenital heart diseases, an echocardiogram, although the aforementioned tests along with clinical features might be sufficient for most cases.

[6] Treatment is based on: Tricuspid atresia is the third most common critical congenital heart defect.