Tetralogy of Fallot
What is tetralogy of Fallot?
The tetralogy of Fallot is a birth defect with 4 parts:
- a hole between the 2 lower heart chambers (the pumping chambers, or ventricles). This is called a ventricular septal defect.
- a narrowing under or at the pulmonary valve (the valve at the opening from the right ventricle to the pulmonary artery, which carries blood to the lungs). This narrowing is called an infundibular stenosis. It can also involve the lung arteries.
- an enlarged right ventricle.
- a misaligned aorta, that sits just over the hole between the ventricles. The aorta is the artery that carries oxygen-rich (red) blood from the left ventricle to the rest of your body.
The hole between the ventricles, allows mixing of red blood with oxygen-poor (blue) blood. The amount of blood going to the lungs is reduced by the narrowing of the pulmonary valve and arteries. Because the right ventricle must do extra work, it gets bigger and thicker. Because some of the blue blood will make its way out of the aorta, the skin of children with tetralogy of Fallot often looks blue (cyanosis).
How does it occur?
The cause of tetralogy of Fallot is unknown.
What are the symptoms?
Children with this birth defect often look blue. The blueness may appear at birth or in infancy. Infants may have spells during which they turn blue, breathe rapidly, and cry. They may pass out. During exercise, older children who have not had surgery often become short of breath and may tire easily. Children may squat during exercise to help them catch their breath. All of these symptoms occur because not enough blood is flowing to the lungs to supply the body with needed oxygen.
These children also have a heart murmur. A heart murmur is an extra sound made between heartbeats. These murmurs are caused by the blood leaving the heart through the narrowed lung artery.
How is it diagnosed?
Your doctor will order a cardiac ultrasound (echocardiogram) to make the diagnosis. An echocardiogram uses sound waves to produce images of the heart. A heart catheterization may be done to get a more exact idea of the heart's structure before surgery. A cardiac catheterization is a procedure in which a thin tube is passed through a blood vessel to check the heart.
How is it treated?
To correct the problem, surgery is done to close the hole between the two lower heart chambers. This usually requires a patch of synthetic material such as Dacron.
The surgeon will also relieve the narrowing at the pulmonary valve. This may be done in several ways:
- In some cases, the surgeon may need to replace the pulmonary valve.
- In other cases, the surgeon will enlarge this area of the heart with a patch of synthetic material or a thin layer of the tissue surrounding the heart (the pericardium).
- If an infant is too sick or the pulmonary arteries are too small for corrective surgery, a small tube is placed between one of the arteries of the aorta and the pulmonary artery. This tube is called a shunt. It permits blood to enter the lungs and allows the lung arteries to grow until corrective surgery can be done.
What can you expect after surgery?
After surgery, most children are able to do all normal things, including sports. Some children need to limit their activities, however. Some may need to take medicine to control heart rate and to improve heart function. Later in life, they may develop abnormal heart rhythms. They will also need to take antibiotics before dental and some other procedures to prevent heart infections.
Children with tetralogy of Fallot should see a cardiologist regularly for the rest of their lives.
Written by Reginald L. Washington, MD, FAAP, FACC, for RelayHealth.
Published by RelayHealth.
© 2009 RelayHealth and/or its affiliates. All Rights Reserved.
