 Hypoplastic left heart syndrome HLHS and related single right ventricle anomalies are the highest risk congenital cardiovascular malformations. Surgical repair begins with the Norwood procedure during the newborn period, a stage II procedure at 4 to 6 months of age, and Fontan procedure at 18 to 36 months. The Norwood procedure remains one of the highest risk procedures in congenital heart surgery. A few small nonrandomized studies of a novel approach to the Norwood procedure have reported improved outcomes. This new approach uses a RV-to-PA shunt to provide pulmonary blood flow rather than the standard MBTS. This multi-center, randomized clinical trial will evaluate early and intermediate-term outcomes for patients undergoing a Norwood procedure with either the RV-to-PA shunt or the MBTS. 