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Atrioventricular Canal Defect—Child

  • Cynthia M. Johnson, MA
Publication Type:


Atrioventricular Canal Defect—Child

(AV Canal Defect—Child; Complete AV Canal—Child; Complete Common AV Canal—Child; Endocardial Cushion Defect—Child)


The heart is made up of two upper chambers and two lower chambers. Usually, blood flows from the upper to lower chamber on the right side of the heart to the lungs. The blood picks up oxygen in the lungs and passes back into the upper chamber of the left side of the heart. It then passes to the lower chamber of the heart and out to the body.

An atrioventricular (AV) canal defect is when there is a large hole in the center of the heart that connects all four chambers. As a result, blood mixes in the different chambers. This means that some of the blood that is sent out to the body has not passed the lungs to pick up oxygen to carry through the rest of the body.

Heart Chambers and Valves.

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Blood Flow Through the Heart.

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AV canal defect is a problem that is present at birth. It is not known exactly why it happens.

Risk Factors

Things that may raise the risk of this problem are:

  • A family history of congenital heart defects
  • Certain chromosomal disorders, such as Down syndrome
  • Prior pregnancy with fetal heart abnormalities or miscarriage
  • Problems in the mother, such as:
    • Being infected with a virus
    • Having poorly controlled diabetes
    • Drinking alcohol
    • Taking certain medicines


Problems may be:

  • Fast breathing
  • Poor feeding
  • Slow growth
  • Bluish skin color
  • Lack of energy
  • Irritability
  • Poor alertness
  • Wheezing
  • Swelling of the legs, ankles, and feet
  • Sweating
  • Fast heartbeat
  • Sudden weight gain


The doctor will ask about your child’s symptoms and health history. A physical exam will be done.

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

Your child's heart function may be tested. This can be done with:


Surgery will be done to correct the defect. The hole will be closed with a patch.

Lifelong heart monitoring will be needed after treatment.


There are no known guidelines to prevent an AV canal defect.





  • Atrioventricular canal defect. Boston Children's Hospital website. Available at: https://www.childrenshospital.org/conditions/atrioventricular-canal-defect.
  • Ventricular septal defect. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/ventricular-septal-defect.


  • Kari Kuenn, MD
Last Updated:

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.