Hypoplastic left heart syndrome is a severe form of congenital heart disease in which most of the structures on the left side of the heart are small, underdeveloped and unable to provide enough blood flow to meet the body's needs. Seeking to optimize the care of children with this condition, Rahul Rathod, MD, a clinical fellow in Children's Department of Cardiology, will conduct a study comparing two standard surgical approaches for increasing blood flow to the pulmonary arteries, which carry blood to the lungs: a systemic to pulmonary-artery shunt or a right ventricle to pulmonary artery conduit.