Tetralogy of Fallot

Tetralogy of Fallot (TOF) is a combination of four heart defects. It is present at birth. These defects make it difficult for your child to get oxygen to the entire body. The four defects are: VSD and overriding aorta can decrease the amount of oxygen in the blood. This makes it difficult for the body to get the oxygen it needs. Pulmonary stenosis and right ventricular hypertrophy can make it difficult for blood to pass to the lungs. This will also decrease the amount of oxygen in the blood.

  • Causes

    A child's heart develops very early in pregnancy. Tetralogy of fallot is caused by a problem during this development. It is not known exactly why these problems happen. Some have been associated with genetics, mother's nutrition, or infections. Most have no known cause.

    Ventricular Septal Defect
    Ventral septal defect
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  • Definition

    Tetralogy of Fallot (TOF) is a combination of four heart defects. It is present at birth. These defects make it difficult for your child to get oxygen to the entire body.

    The four defects are:

    • Ventricular septal defect (VSD)
      —A hole in the heart. It is on a wall that separates the two lower chambers.
    • Overriding aorta—The aorta, which is the body's largest artery, comes out of the left ventricle, but partially covers or comes out of the right ventricle
    • Pulmonary stenosis—The valve in the heart that allows blood to pass from the heart toward the lungs is too narrow.
    • Right ventricular hypertrophy—The muscle on the right side of the heart is too thick.

    VSD and overriding aorta can decrease the amount of oxygen in the blood. This makes it difficult for the body to get the oxygen it needs. Pulmonary stenosis and right ventricular hypertrophy can make it difficult for blood to pass to the lungs. This will also decrease the amount of oxygen in the blood.

  • Diagnosis

    A diagnosis of TOF is often made soon after birth. The doctor will ask about your child's symptoms and the mother's medical history. A physical exam will be done.

    The doctor may begin tests based on your child's symptoms. A newborn with blue skin will often be given extra oxygen. If the oxygen does not help, a heart defect may be suspected. If the skin color is normal, the first clue is a loud heart murmur.

    Images may be taken of your child's heart. This can be done with:

    • Chest x-ray
    • Echocardiogram


    Heart problems may also be detected using
    cardiac catheterization
    .

  • Prevention

    There are no guidelines for preventing TOF.

  • Risk Factors

    Factors that may increase the risk of TOF include:

    • Family history
    • Mother's use of retinoic acid
    • Mother's use of oral fluconazole
    • Mother's alcohol use
    • Mother has infection with rubella
    • Pregnancy in mothers over 40
    • Maternal diabetes


    Some people who have TOF also have a chromosome disorder. This may include
    Down syndrome
    , CHARGE syndrome, and VACTERL association.

  • Symptoms

    For most, symptoms will appear during the first few weeks of life. For children with mild TOF, symptoms may not appear until much later. They may not show until your child or young adult becomes more active. Physical activity places more demand on the heart. A heart with TOF can not keep up with the extra demand. This will make symptoms appear. Without treatment, symptoms will continue to occur.

    Symptoms may include:

    • Blue coloring of the skin and lips caused by a low oxygen level in the blood
    • Shortness of breath and rapid breathing caused by a low oxygen level in the blood
    • Older children may have shortness of breath and fainting spells when exercising
    • Clubbing of the fingers

    In severe cases, a tetralogy spell may occur. This happens when the oxygen level in the blood drops suddenly. Symptoms include:

    • Lips and skin become very blue
    • Baby will become breathless and irritable
    • Baby may become sleepy or unconscious if low oxygen levels continue
    • Older children may squat with their knees on their chest to help recover from the breathlessness

  • Treatment

    Medications may be given to relieve symptoms. They may also help to prevent complications like the tetralogy spell.

    The defects of the heart are treated with surgery. Surgical options include: