In Hypoplastic Left Heart, blood flow to the body is severely restricted. When the Patent Ductus Arteriosus (PDA) closes, the infant develops profound shock.

In a surgical operation known as the Norwood Procedure (see the mouseover diagram), a major blood vessel to the body (aorta) is constructed from the base of the pulmonary artery and the narrowed aorta.

In addition, a small tube made of Gore-Tex (known as a Modified Blalock-Taussig Shunt), shown in yellow on the diagram, is inserted between the branches of the pulmonary artery (PA) and a branch of the aorta to ensure blood flow to the lungs after the PDA is closed off.

All forms of single ventricle are a staged repair with an initial neonatal repair as described above, followed by a Bidirectional Glenn at 6 months and a Fontan (Bicaval pulmonary anastomosis) at 3-4 years of age.