Tetralogy of Fallot
Information on Kids Health
Tetralogy of fallot (TOF) is a disorder that consists of four separate defects:
- An overriding aorta - the aorta is located over the ventricular septal defect instead of over the left ventricle
- Ventricular Septal Defect (VSD)
- An enlarged and thickened right ventricle
- Pulmonary Stenosis
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Concerns and Symptoms
This defect causes oxygen-poor blood from the right ventricle to flow through the opening and mix with oxygen-rich blood in the left ventricle. More of the oxygen-poor blood will then flow through the left ventricle, into the aorta and out to the rest of the body.
Because the outflow from the right ventricle to the pulmonary artery is also obstructed, less blood flows to the lungs to be reoxygenated. When the body does not receive enough oxygen in the circulating blood, the child can become cyanotic, or blue.
Children with tetralogy of fallot usually show symptoms in infancy. Symptoms include cyanosis (blue color in skin, lips and nail beds), irritability, fatigue, pallor and clammy skin.
Surgery is required to repair tetralogy of fallot. Depending on the age of the child and the severity of symptoms, surgery may be performed in stages, or all at once. The operation is performed under general anesthesia, which means the child will be asleep during surgery.
If the repair is being performed in stages, the first operation involves placing a Blalock-Taussig shunt (a Gore-Tex tube between the subclavian artery and the pulmonary artery). The shunt artificially increases blood flow to the lungs until the child is ready for a complete repair. The operation is done through a vertical incision in the front of the chest, over the breastbone. The heart-lung bypass machine is not needed during this operation.
If the repair is being performed all at once, the surgeon will make a vertical incision in the front of the chest, opens the breastbone and exposes the heart. Blood from the heart is redirected to a bypass machine. The bypass machine does the job of the heart and lungs during the operation.
The surgeon then opens the heart and identifies the ventricular defect. He cuts a small piece of Gore-Tex in the size and shape of the defect, and uses this as a patch. He then opens the obstruction between the right ventricle and the pulmonary artery. He may also enlarge the pulmonary artery with a patch.
After the defects are repaired and the heart closed, the surgeon shuts down the heart-lung bypass machine, and the heart starts beating again. The surgeon then closes the breastbone and chest incision, and applies bandages to the incision site.