Tetralogy of Fallot is a combination of four heart defects that are present at birth (congenital). The condition develops in an unborn baby early in pregnancy, while the heart is developing. Together, these defects cause problems in blood flow, which makes it difficult for the body to get enough oxygen-rich blood.

• Ventricular septal defect. This is a hole in the wall between the two lower chambers of the heart (ventricles). The hole allows blood with oxygen to mix with blood without oxygen.
• Overriding aorta. Normally, the aorta is attached to the left ventricle. In an overriding aorta, it is located between the ventricles and over the ventricular septal defect. An overriding aorta allows the oxygen-poor blood from the right ventricle to travel to the rest of the body.
• Pulmonary stenosis. This is a condition in which the valve between the right ventricle and the artery that leads to the lungs (pulmonary artery) is too narrow. Pulmonary stenosis results in less blood moving to the lungs than is normal.
• Right ventricular hypertrophy. This is an enlargement and thickening of the right ventricle. It occurs because the heart has to work harder than normal to move blood through the pulmonary artery.

Tetralogy of Fallot is usually discovered within the first year of life when a health care provider hears an abnormal sound (heart murmur) when listening to the heart beat.

What are the causes?

The cause of this condition is not known. In some cases, it may be caused by genes that are passed from parent to child (inherited).

What increases the risk?

• Children with DiGeorge syndrome or Down syndrome.
• Children whose mothers drank a lot of alcohol during pregnancy.
• Children whose mothers were over 40 years of age at the time of pregnancy.
• Children whose mothers had poor nutrition or a viral disease such as rubella during pregnancy.

What are the signs or symptoms?

• A bluish tint to the skin, fingertips, or lips (cyanosis).
• Difficulty breathing.
• Tiredness and limpness.
• A lack of response when being talked to or touched.
• Fussiness.
• A seizure.

When these symptoms occur suddenly, it is called a tetralogy spell. Tetralogy spells occur when there is a sudden drop in blood oxygen levels.

How is this diagnosed?

• A physical exam.
• Chest X-ray.
• Electrocardiogram (ECG) to check for irregular heartbeats (arrhythmias).
• Blood tests.
• A pulse oximetry test. This test checks the amount of oxygen in your child's blood.
• An exercise stress test. During this test, your child exercises or is given medicine to make the heart work harder and beat faster while heart tests are performed.

Your child may see a heart specialist (cardiologist) to manage this condition.

How is this treated?

• Open-heart surgery. This surgery is done within the first year after birth:
  • To close the ventricular septal defect.
  • To widen the pulmonary artery.
  • To correct the problems that are caused by the other defects.
• Shunting. This temporary surgery is performed on children who cannot have open-heart surgery for any reason, such as those who are very small for their age. The purpose of the surgery is to:
  • Place a device called a shunt between the pulmonary artery and the aorta.
  • Create a pathway between the pulmonary artery and the aorta, allowing more blood to travel to the lungs.

Follow these instructions at home:

Tetralogy spells

• If your child has a tetralogy spell:
  • Bring your child's knees up tight against his or her chest (the knee-chest position).
  • Attempt to calm your child.
  • If your child's symptoms do not improve right away or if your child has cyanosis, call local emergency services (911 in the U.S.).

Dental care

• Talk with your child's health care provider before taking your child to the dentist for any procedure, including dental cleanings.
  • Ask your child's health care provider if antibiotic medicines are needed before the procedure. This question will be important throughout your child's lifetime.
• Schedule routine dental care to prevent tooth decay. Tooth decay can lead to infections in the heart.

General instructions

• Tell all of your child's health care providers (including dentists) about your child's condition.
• Have your child wear a medical alert bracelet or necklace. This tells anyone caring for your child in an emergency that your child has a heart condition.
• Limit certain types of activities if told by your child's health care provider.
• Consider getting counseling or joining a parental support group if you are feeling stressed or having trouble coping with your child's condition.
• If your child had surgery, follow post-surgery care instructions.
• Keep all follow-up visits as told by your child's health care provider. Your child will need to see a health care provider and heart specialist (cardiologist) regularly for life. This is important because your child's health care provider will check for new problems and make sure that any existing problems are under control.

Get help right away if your child:

• Has trouble breathing.
• Becomes tired and limp.
• Does not respond when being talked to or touched.
• Is unusually fussy.
• Has a seizure.
• Has a bluish tint to the skin, fingertips, or lips (cyanosis). If your child has cyanosis, call local emergency services (911 in the U.S.).

Summary

• Tetralogy of Fallot is a combination of four heart defects that are present at birth (congenital). These defects make it difficult for the body to get enough oxygen-rich blood.
• This condition is usually treated with surgery.
• Your child will need to see a heart specialist (cardiologist) throughout his or her life.