Approximately 3,000 U.S. children are born annually with severe heart defects in which one ventricle is too small or weak to pump effectively. While a single ventricle defect is not the most common birth abnormality, it is one of the most challenging due to its surgical complexity and high morbidity and mortality rate. As a result, high-volume facilities, such as the Childrens Hospital of Philadelphia (CHOP), have developed strategic programs to better manage and treat such patients.