Tetralogy of Fallot seems an odd name for a heart defect, but that's easily explained.

The "Tetralogy" means four, as the congenital defect can be found in four anatomical abnormalities of the heart.Although it can manifest as malformation in four areas, it always involves three.It's named after French physician Etienne-LouisFallot, who was among the first to describe it.The condition was thought to be untreatable until 1944, when surgeon Alfred Blalock, cardiologist Helen B. Taussig and lab assistant Vivien Thomas developed a surgical procedure at Johns Hopkins University.The first Blalock-Thomas-Taussig surgery was performed on 15-month-old Eileen Saxon on Nov. 29, 1944.The surgery was "palliative," meaning that it alleviated symptoms, but it was not curative.The first total repair was done on an 11-year-old boy at the University of Minnesota in 1954, where a team of surgeons were led by C. Walton Lillehei.Total repair initially carried a high mortality risk, but the risk has declined steadily over the years. Surgery is now done on infants 1 year old or younger, with less than 5 percent mortality.Tetralogy of Fallot occurs in approximately 400 per million live births. Its cause is thought to be environmental or genetic factors, or a combination.It occurs only slightly more often in males than females. Congenital heart defects are now diagnosed with echocardiography and can be done prenatally.The condition causes low oxygenation of blood due to the mixing of oxygenated and deoxygenated bloods in the left ventricle of the heart because of defects and obstructions. The primary symptom is low blood oxygen with or without cyanosis (blue skin) from birth or developing in the first year of life. Other symptoms include a heart murmur, difficulty in feeding, failure to gain weight and slow growth.