Tetralogy of Fallot is a combination of structural problems that develop in the heart before birth. Together, these four congenital heart defects allow oxygen-rich and oxygen-poor blood to mix, which can lead to high pressure in the heart and reduced oxygen to the body. The four conditions that comprise tetralogy of Fallot are:
- Ventricular septal defect (VSD): a hole between the bottom two chambers of the heart.
- Overriding aorta: your body’s main artery connects to both of the heart’s lower chambers instead of just the left chamber.
- Pulmonary artery stenosis: constriction in the artery that transports blood from the heart to the lungs.
- Right ventricular hypertrophy: the muscle in the lower right heart chamber thickens as it works harder to compensate for other heart abnormalities.
Disease Spectrum
Tetralogy of Fallot ranges in severity. The following subtypes of Tetralogy of Fallot are especially rare and severe:
- Tetralogy of Fallot with pulmonary atresia: The pulmonary valve is missing and sealed shut. This can lead to undersized pulmonary arteries and require intervention as a baby.
- Tetralogy of Fallot with major aortopulmonary collaterals: Pulmonary atresia prompts the formation of new blood vessels to supply blood to the lungs. This can require multiple surgeries to promote pulmonary artery growth.
- Tetralogy of Fallot with absent pulmonary valve: The pulmonary valve leaflets do not develop, which can result in significant dilation of the pulmonary arteries and may cause airway concerns.