The incidence of congenital heart disease detectable by routine clinical examination has been estimated to be 7.5 per 1,000 live births (1). The incidence of congenital heart anomalies in neonates seen with detailed echocardiographic examination is four- to 10-fold higher, with most of the difference being clinically insignificant ventricular septal defects (20-50 per 1,000) and nonstenotic bicommissural aortic valves (2). Severe forms of cardiac anomalies requiring cardiac catheterization or surgery, or resulting in death, occur in 2.5 to 3 infants per 1,000 births (2,3). Almost one-half of these are diagnosed during the first week of life. Additionally, moderately severe forms of cardiac anomalies occur in another 3 per 1,000 live births, and another 13 of 1,000 live births have a bicommissural aortic valve that may require care eventually (2). The distributions of congenital heart anomalies in newborns seen at a primary and a tertiary pediatric cardiac center are shown in Table 33-1.