Complete Atrioventricular Canal Defect, Pediatric

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Complete atrioventricular canal defect (CAVC) is a heart condition in which there is a large hole in the centre of the heart and only one heart valve. Normally, the heart is divided into four chambers, and there is one valve on each side of the heart. The chambers on the right side of the heart receive blood from the body and pump it to the lungs where the blood gets oxygen. The chambers on the left side of the heart get the oxygen-rich blood from the lungs and pump it back out to the body.

In CAVC, the blood in the different chambers mixes, and the heart valve may not close tightly. Blood flows where it normally does not, which makes the heart work much harder than normal. This can lead to congestive heart failure (CHF).

CAVC is a problem which is present at birth (congenital heart defect). Children with CAVC usually start to have symptoms within a few weeks after birth.

What are the causes?

The cause of this condition is not known.

What increases the risk?

This condition is more likely to develop in:

  • Children who have Down syndrome.

  • Children who have certain unwanted changes in their genes (genetic mutations).

What are the signs or symptoms?

Symptoms of this condition depend on the location and size of the hole in the heart. They may include:

  • Trouble breathing or rapid breathing.

  • Pale or bluish skin colour.

  • Pounding heart with a weak pulse.

  • Trouble feeding and gaining weight.

  • Tiring easily.

  • Swelling of the abdomen or legs.

How is this diagnosed?

This condition may be diagnosed in two ways:

  • During your pregnancy, as part of your antenatal screening. An imaging test that uses sound waves to create an image of your baby’s heart (foetal echocardiogram) may show the defect.

  • After birth, during your baby’s routine examination. Diagnosis may be based on:

    • Your baby’s symptoms.

    • A chest X-ray in which your baby’s heart looks larger than normal.

    • A physical examination to listen for a “whooshing” sound (murmur) instead of a normal heartbeat sound.

    • An echocardiogram.

How is this treated?

This condition is treated with open heart surgery to repair the defect. In this surgery:

  • One or two patches will be placed on your baby’s heart to close the hole. These patches will become a permanent part of your baby’s heart.

  • Your baby’s single heart valve will be separated to make two valves between the upper and lower chambers on each side of the heart.

Depending on how severe your child’s symptoms are, this surgery may be completed during infancy, or it may be started during infancy and completed when your baby is older and stronger. Until then, your baby may require:

  • Medicines to improve circulation and help reduce symptoms related to CAVC.

  • Close monitoring of nutrition.

Summary

  • Complete atrioventricular canal defect (CAVC) is a heart condition in which there is a large hole in the centre of the heart and only one heart valve.

  • The condition may be diagnosed during your pregnancy, as part of your antenatal screening, or shortly after your baby is born.

  • Depending on how severe your child’s symptoms are, surgery to repair the defect may be completed during infancy, or it may be started during infancy and completed when your baby is older and stronger.

This information is not intended to replace advice given to you by your health care provider. Make sure you discuss any questions you have with your health care provider.