Tetrology of Fallot

Tetrology of Fallot is a congenital heart defect. A combination of four abnormalities in the heart allow oxygen-rich and oxygen-depleted blood to mix. The resulting low-oxygen blood then circulates through the body.

What is going on in the body?

Normally, the right side of the heart pumps oxygen-poor blood to the lungs. Once enriched by oxygen, this blood returns to the left side of the heart to be pumped to tissues throughout the body. A wall called the septum separates the two sides of the heart.

Tetrology of Fallot is a combination of four heart defects that are apparent at birth. These defects allow the blood supplies to mix so that the blood sent to cells throughout the body is low in oxygen. Blood flow to the lungs is decreased, too. Not getting enough oxygen can cause vital organs to fail.

What are the causes and risks of the condition?

The cause of tetrology of Fallot is unknown. However, a baby is more likely to be born with tetrology of Fallot if the mother has one of the following conditions:

What are the signs and symptoms of the condition?

Infants with this condition usually have a heart murmur that can be heard at birth, or shortly thereafter. They have a bluish-purple color to the skin, a condition called cyanosis. The child is cyanotic because the blood circulating through the body does not have enough oxygen. Between the ages of 2 months and 2 years, children with tetrology of Fallot may experience "blue" spells. These spells may be brought on by crying, straining to have a bowel movement, or fever.

A child who has tetrology of Fallot tends to develop slowly, eat poorly, and grow slowly. He or she may get short of breath, especially when exercising. A change in the shape of the fingertips, called clubbing, is another sign of this condition.

How is the condition diagnosed?

After a complete history and physical exam are done, a variety of imaging tests can confirm the diagnosis.

What can be done to prevent the condition?

Many times nothing can be done to prevent the disease. However, it may help if a pregnant woman avoids certain factors known to put a fetus at higher risk for this disease, such as alcohol.

What are the long-term effects of the condition?

Unless the child's heart can be surgically repaired, tetralogy of Fallot is fatal. Treatment may be affected by complications, such as the following:

What are the risks to others?

Tetralogy of Fallot is not contagious, and poses no risks to others.

What are the treatments for the condition?

Cyanotic spells usually respond to oxygen, morphine, and the knee-to-chest position. These spells are usually a sign that surgery is needed.

Sometimes an injection of a hormone called prostaglandin E can help improve blood flow through the lungs. This is done until surgery can repair the problem.

Open heart surgery is done to close the hole in the septum, remove extra heart muscle, and open or repair the pulmonary valve. This surgery is recommended as early as possible in nearly all cases. It can be done only if the child has well-developed pulmonary arteries. These arteries carry blood to the lungs. If they are not well developed, temporary surgery may be done to increase blood flow to the lungs. This will give a child some time until the arteries develop more and full repair can be done.

What are the side effects of the treatments?

Prostaglandin E can stop a child's breathing. It should be used in a setting where resuscitation equipment is available. Surgery may cause bleeding, infection, and allergic reaction to anesthesia.

Other problems can arise after surgery. Restoring normal blood flow may trigger the following:

What happens after treatment for the condition?

After surgery, improvements should be seen in the symptoms linked to low-oxygen levels, such as cynanotic spells, and the child's tolerance of exercise. However, heart function is not fully normal. A variety of problems called heart blocks and, rarely, sudden death can occur years after surgery.

How is the condition monitored?

Visits to the doctor are scheduled regularly to check that the heart is healing properly and that there are no new symptoms. Testing may need to be repeated to ensure that heart disease is not worsening. People who have had tetralogy of Fallot should take antibiotics before any future surgery or dental work. This will help them avoid serious heart infections. Any new or worsening symptoms should be reported to the healthcare provider.

Author:Eric Berlin, MD
Date Written:
Editor:Ballenberg, Sally, BS
Edit Date:02/15/01
Reviewer:Gail Hendrickson, RN, BS
Date Reviewed:07/27/01

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