by EBSCO Medical Review Board
(AV Canal Defect—Child; Complete AV Canal—Child; Complete Common AV Canal—Child; Endocardial Cushion Defect—Child)


An atrioventricular (AV) canal defect is a rare heart defect. There is a large hole in the center of the heart that connects all four chambers.

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 AV canal defect causes blood in the different chambers to mix. This means that some of the blood that is sent out to the body has not passed the lungs to pick up oxygen. The body does not get enough oxygen.

Heart Chambers and Valves
heart anatomy
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Blood Flow Through the Heart
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AV canal defect is a congenital defect. This means that a baby is born with it. It is not known exactly why this 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
  • Lowered 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 medical history. A physical exam will be done.

Images 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 this health problem.


American Heart Association 

Family Doctor—American Family Physician 


Canadian Cardiovascular Society 

Heart and Stroke Foundation of Canada 


Atrioventricular canal defect. Boston Children's Hospital website. Available at: Accessed March 10, 2021.

Complete atrioventricular canal defect (CAVC). American Heart Association website. Available at: Accessed March 10, 2021.

Minette MS, Sahn DJ. Ventricular septal defects. Circulation. 2006 Nov 14;114(20):2190-2197.

Ventricular septal defect. EBSCO DynaMed website. Available at: Accessed March 10, 2021.

Revision Information

  • Reviewer: EBSCO Medical Review Board Kari Kassir, MD
  • Review Date: 12/2020
  • Update Date: 03/10/2021