Tetralogy of Fallot (TOF) is a congenital heart defect that is present at birth.
Classically there are four defects:
- A ventricular septal defect (a hole between the two ventricles)
- Pulmonary stenosis, narrowing of the pulmonary valve (pulmonary valvular stenosis)
- Right ventricular hypertrophy (enlargement of the right ventricle)
- An overriding aorta,