tetralogy of Fallot
Last edited 02/2023 and last reviewed 05/2023
Tetralogy of fallot is probably best thought of as having two essential features:
- a large ventricular septal defect, usually sited high up in the membranous part of the septum beneath the aortic valve, such that the right ventricle ejects directly into the aorta; not via the left ventricle
- right ventricular outflow tract obstruction. It is this element that determines much of the severity of the condition
In addition to, and at least in part as a consequence of this, there are the other two features of the tetrad:
- overriding aorta, as a result of the malformation from the ventricular septal defect, which may be dextropositioned
- right ventricular hypertrophy - as a result of, but not totally caused by the outflow obstruction
TOF represents 7% to 10% of congenital defects, affecting males and females equally and occurring in 3 to 5 of every 10,000 live births (1)
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