What is an atrioventricular canal defect?

An atrioventricular canal defect, also called AV canal, is a problem with how the heart develops. Children born with AV canal have holes between the heart's four chambers. They may also have heart valves that are not formed correctly. These problems can cause the blood to flow in ways it should not inside the heart, which can cause a strain on the heart and lungs.

There are two main types of AV canal:

  • Complete atrioventricular canal defect: In this type, there is a large hole in the middle of the heart, between all four of the heart’s chambers. There is also a problem with the valves — there is only one valve instead of the normal two valves separating the upper and lower heart chambers. This one valve may not be formed correctly or close properly.
  • Incomplete or partial atrioventricular canal defect: This type of AV canal is less severe than a complete AV canal defect. Usually, there is a hole between the upper chambers (atria) or lower chambers (ventricles) of the heart. And while there are two valves, one often does not close correctly, allowing blood to leak backward through the valve.

What are the symptoms of atrioventricular canal defects?

For babies with a complete AV canal, symptoms usually develop a few weeks after birth. Symptoms may take longer to develop in children with partial AV canal. Common symptoms may include:

  • Trouble breathing
  • Weak pulse
  • Tiredness
  • A bluish color to the skin or nails
  • Poor growth

What causes atrioventricular septal defect?

There is no known cause of AV canal. However, it is more common in babies with Down syndrome.

How is atrioventricular septal defect treated?

Most children with AV canal need surgery to repair the problems. The specific type of surgery your child needs, and when it is done, will depend on which type of AV canal defect they have.

Surgery for AV canal typically involves:

  • Closing any holes between the heart’s chambers with patches.
  • For children with complete AV canal, creating two separate valves from the one existing valve.
  • For children with partial AV canal, repairing or replacing a valve that does not close properly.

Your care team at Arkansas Children’s is experienced in treating all types of AV canal and will work with you to come up with the best treatment plan for your child’s individual needs.

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