Tetralogy of Fallot

Tetralogy of Fallot is a congenital heart condition defined by four cardiac abnormalities occurring together: pulmonary stenosis, a narrowing of the exit from the right ventricle; a ventricular septal defect, a hole between the two ventricles; right ventricular hypertrophy, a thickened right ventricle wall; and an overriding aorta, where the aorta sits positioned to receive blood from both ventricles. At birth, affected children may show no symptoms or present with severe ones; most develop bluish skin from low blood oxygen, and during crying or bowel movements can suffer a tet spell, turning cyanotic, struggling to breathe, going limp and sometimes losing consciousness. The precise cause is typically unknown, though risk factors include maternal diabetes, infections during pregnancy such as rubella, certain lifestyle factors, and maternal age over thirty five. The condition was first described in 1671 by Danish researcher Niels Steensen, with French physician Etienne-Louis Arthur Fallot publishing a fuller description in 1888, after whom it is now named.