Definition

Tetralogy of Fallot (TOF) is a combination of these four heart defects that are present at birth:

• Ventricular septal defect (VSD)—A hole between the lower chambers of the heart
• Overriding aorta—An aorta (blood vessel) that lies over the hole in the lower chambers
• Pulmonary stenosis—A narrowing or thickening of the valve that connects the heart to the lungs
• Right ventricular hypertrophy—A thickening of the muscle on the right side of the heart

TOF can decrease the amount of oxygen in the blood. This makes it hard for the body to get oxygen.

Causes

TOF is caused by a problem in the way a child's heart develops during pregnancy. It is not known this happens. Genes and the environment may play a role.

Ventricular Septal Defect Copyright © Nucleus Medical Media, Inc.

Risk Factors

TOF is more common in people who have other family members with TOF or other genetic disorders associated with it.

These things in the mother may raise the risk are:

• The use of retinoic acid
• Uncontrolled diabetes
• Untreated phenylketonuria
• Rubella

Symptoms

Most babies have symptoms in the first few weeks of life. Children with mild TOF may not have problems until later.

Low oxygen levels in the blood may cause these problems:

• Blue coloring of the skin and lips
• Shortness of breath and rapid breathing
• Being very tired
• Fainting
• Irritability
• Clubbing of the fingertips in older children

Diagnosis

TOF may be suspected before birth using prenatal screenings, such as:

• Genetic testing
• Ultrasound

The diagnosis may also be suspected based on a baby's health soon after birth.

An image will be taken to confirm the diagnosis. This can be done with an echocardiogram.

Treatment

Medicine may be given to ease symptoms. Surgery will also be needed. Choices are:

Prevention

There are no current guidelines to prevent TOF.