Tetralogy of Fallot

Tetralogy of Fallot (TOF) is a congenital heart defect.[4] Symptoms at birth may vary from none to severe.[9] Later, there are typically episodes of bluish color to the skin known as cyanosis.[2] When affected babies cry or have a bowel movement, they may develop a “tet spell” where they turn very blue, have difficulty breathing, become limp, and occasionally lose consciousness.[2] Other symptoms may include a heart murmurfinger clubbing, and easy tiring upon breastfeeding.[2]

The cause is typically not known.[5] Risk factors include a mother who uses alcohol, has diabetes, is over the age of 40, or gets rubella during pregnancy.[5] It may also be associated with Down syndrome.[10] Classically there are four defects:[4]

TOF is typically treated by open heart surgery in the first year of life.[8] The timing of surgery depends on the baby’s symptoms and size.[8] The procedure involves increasing the size of the pulmonary valve and pulmonary arteries and repairing the ventricular septal defect.[8] In babies who are too small, a temporary surgery may be done with plans for a second surgery when the baby is bigger.[8] With proper care, most people who are affected live to be adults.[4] Long-term problems may include an irregular heart rate and pulmonary regurgitation.[3]

TOF occurs in about 1 in 2,000 newborns.[4] Males and females are affected equally.[4] It is the most common complex congenital heart defect, accounting for about 10 percent of cases.[11][12] It was initially described in 1671 by Niels Stensen.[1][13] A further description was published in 1888 by the French physician Étienne-Louis Arthur Fallot, after whom it is named.[1][14] The first total surgical repair was carried out in 1954.[3]


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