The pulmonary valve annulus is usually small
but not hypoplastic. The pulmonary valve leaflets are well formed but
fused. The main pulmonary artery is small but rarely is atretic as seen
with pulmonary atresia and ventricular septal defect. The patent ductus
arteriosus is usually small because it carries blood from aorta to
pulmonary arteries in utero and not the other way around as in normal.
Therefore, much less blood travels through the PDA in utero. The right
ventricle might be of several types.
Type I is tripartite.
Type II bipartite (atretic body).
Type III unipartite (atretic body and
Tricuspid valve might be deformed and
Sinus nodes from the right ventricle cavity
to myocardium and from myocardium to coronary arteries. Collateral
circulation from the descending aorta to pulmonary arteries is rare. Other
congenital heart disease is rarely associated with this one. Right aortic
arch is not known to occur in pulmonary atresia with intact ventricular