What is atrioventricular septal defect?

Atrioventricular septal defect (AVSD) is a combination of heart problems that affect the walls between the chambers of the heart and the valves between the upper and lower heart chambers. It is also called atrioventricular canal defect. The condition is congenital, which means a baby is born with it. If not treated, AVSD can cause many problems involving the heart and lungs.

The combination of defects includes:

  • Atrial septal defect (ASD): a hole in the wall that separates the two upper heart chambers (atria).
  • Ventricular septal defect (VSD): a hole in the wall that separates the two lower heart chambers (ventricles).
  • Abnormalities of the mitral and tricuspid valves: when these valves are not formed correctly, they allow blood to flow backwards instead of being pumped forward out of the heart.


Symptoms of AVSD can include:

  • poor feeding or poor weight gain
  • rapid, congested or heavy breathing
  • pale or cool skin
  • fatigue
  • sweating
  • rapid heart rate
  • bluish color to the skin
  • heart murmur


To help diagnose AVSD, your child’s doctor may order one or more of the following tests:

  • echocardiogram (cardiac ultrasound)
  • electrocardiogram (EKG)
  • cardiac magnetic resonance imaging (MRI)
  • chest x-ray
  • cardiac catheterization


AVSD is almost always treated with surgery. Some children may benefit from medications until they are able to have surgery.

Learn more about Pediatric Cardiology services at Boston Children’s Health Physicians.

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