Tetralogy of Fallot
Tetralogy of Fallot is a combination of four different heart problems that include:
Pulmonary stenosis: A condition where the pulmonary artery (that carries blue blood from the right ventricle to the lungs to be oxygenated) is blocked. Either the muscle below or above the valve, or the valve itself, may be too narrow or underdeveloped, impeding blood flow.
Ventricular septal defect (VSD): A hole between the ventricles, the heart's two lower pumping chambers.
Overriding aorta: The aorta (the largest blood vessel in the heart, which carries pink blood to the body) is not positioned correctly and straddles both the right and left ventricles just above the VSD.
Right ventricular (RV) hypertrophy: The right ventricle is the lower heart chamber of the heart that pumps blue blood to the pulmonary arteries. Hypertrophy is when the chamber's muscle wall becomes thickened, where it is normally thin. This occurs in TOF because of the extra effort the muscle exert with TOF anatomy.
How we diagnose tetralogy of Fallot
When babies are born with TOF, they can be cyanotic or non-cyanotic. Cyanotic babies usually do not respond to supplemental oxygen after birth. The first indication of TOF is usually a loud murmur heard on exam. In cases of either cyanosis or heart murmur, we suspect cardiac disease and perform an echocardiogram. On occasion a cardiac catheterization is needed to assess the pulmonary arteries.
Tetralogy of Fallot
How we treat tetralogy of Fallot
If a baby with TOF has extremely low oxygen saturations after birth, we sometimes begin a prostaglandin infusion to provide increased pulmonary blood flow until surgical correction can be performed.
Surgical treatment of TOF depends on the severity of the pulmonary stenosis. If the pulmonary arteries are too small, a baby may need an additional palliative operation in the first few months of life. This operation involves placing a shunt to force more blood into the pulmonary arteries, which causes them to grow over time. If the branches of the pulmonary artery are nearly normal, only one complete operation is needed around six months of age. Complete repair of TOF consists of closing the ventricular septal defect with a patch, so that the aorta only arises from the left ventricle. The repair also enlarges the right ventricle outflow tract, pulmonary valve, and branch pulmonary arteries.