Tetralogy of Fallot is a heart birth defect that causes cyanosis in the newborn. Cyanosis is a blue color to the lips, nails or skin, caused by a low oxygen levels in the bloodstream.

Tetralogy of Fallot has four key features:

• Ventricular septal defect:
• A hole in the septum that separates the ventricles
• Pulmonary stenosis:
• An obstruction of blood flow from the right ventricle to the lungs
• Overriding aorta:
• The opening to the aorta communicates with the ventricular septal defect. This causes some oxygen-poor blood to be pumped to the body.
• Right ventricular hypertrophy:
• A thickened and enlarged right ventricle

Surgery is required to treat Tetralogy of Fallot. The timing of the surgery is usually determined by the severity of the pulmonary stenosis. In most cases, a series of operations is required to correct the birth defect.

This is a rare condition that affects approximately 5 out of every 10,000 babies.