Fetal TOF - Absent Pulmonary Valve Syndrome

Case of Tetralogy of Fallot with absent pulmonary valve. There is overriding aorta with a large ventricular septal defect (VSD). There is signs of pulmonary stenosis and severe pulmonary insufficiency, leading to severe main and branch pulmonary and arteries dilatation (the LPA and RPA are aneurysmal - whale tale sign). The arterial duct is not patent, as commonly seen in this disease and possibly contributive to the dilatation (absence of a pop-off leading to progressive enlargement). Absent pulmonary valve syndrome may be found in TOF-Absent pulmonary valve (or Absent pulmonary valve syndrome with VSD), or in the context of absent pulmonary valve syndrome with intact ventricular septum and tricuspid atresia (Non-Fallot type APVS). Non-Fallot type of APVS may also be seen without tricuspid atresia. Absent pulmonary valve syndrome may be suspected in the presence of "Bow Tie" or ballooning of pulmonary arteries, also known as the "whale tale sign".

More on post-natal Tetralogy of Fallot here.

4 chamber view

4 chamber view with colour

The pulmonary arteries can be appreciated. They are significantly enlarged.

There is to-and-fro flow through the RVOT with significant pulmonary insufficiency.

Again, one may appreciate in 2D B-mode the significant enlargement of the pulmonary arteries (Bow Tie pulmonary arteries or whale tale sign). The VSD may be observed briefly in the sweep.

Other sweeps outlining the pulmonary arteries.

2D mode and Colour mode outlining the MPA enlargement. Colour mode outlines the to-and-fro flow secondary to the significant pulmonary regurgitation.

View showing the dilatation of the LPA and RPA.

Colour indicates retrograde flow in the LPA and RPA from the pulmonary insufficiency, as well as some degree of acceleration in systole - outlining the moderate underlying hypoplasia of the pulmonary annulus (leading to post-natal pulmonary stenosis).

Colour free with the Red colour (insufficiency), Blue colour (anterograde acceleration) and the last screenshot outlines the rudimentary pulmonary valve.