Congenital heart disease (CHD) is the name given to any heart defect or malformation that is present at birth. Most types of CHD involve a deformity within the heart and/or the large blood vessels connected to the heart (e.g., aorta, pulmonary artery). 

In some patients, the defect(s) may be mild and unnoticed at birth, then diagnosed later in life. In other children, the effects of the defect(s) are so severe that diagnosis occurs either before birth or during the perinatal (newborn) period. With the sophisticated medical technology now available for diagnosis and treatment, many babies born with congenital heart disease can go on to lead healthy, normal and full adult lives.

Congenital heart disease is the most common of all major birth defects with approximately 36,000 American–born babies every year with CHD, according to the American Heart Association (AHA) 2006 Heart and Stroke Statistical Update. However, the number of children born with CHD outside the U.S. is substantially higher, due to the lack of adequate medical care in poorer countries. The March of Dimes estimates that over one million children were born with CHD worldwide in 2001.

The most common congenital heart defect requiring medical intervention is a ventricular septal defect (14 to 16 percent). Other common defects include tetralogy of Fallot (9 to 14 percent), transposition of the great arteries (10 to 11 percent) and coarctation of the aorta (8 to 11 percent). In 2004, more than 4,100 deaths were caused by congenital heart defects, making them the most common cause of infant death from birth defects. Fortunately, however, the overall death rate due to congenital heart disease has been steadily declining. Between 1979 and 1997, the death rate from all congenital heart defects declined 39 percent. The mortality rate varies significantly with the type of defect. Overall, the death rate due to congenital heart disease is as follows: