Common Atrioventricular Canal Defect

If your child is diagnosed with an atrioventricular canal defect (also known as atrioventricular septal defect, or AVSD), your worry and concern may be overwhelming. To help you through this stressful time, our pediatric cardiology specialists can explain the condition.  And our Mount Sinai Kravis Children’s Heart Center pediatric cardiac surgeon has the expertise to repair your child’s atrioventricular canal defect surgically. 

We specialize in treating the smallest hearts, and, we are available to advise you on the best approach for your child. 

About Atrioventricular Canal Defect

There are two main types of common atrioventricular canal defects—complete and partial.

Complete common atrioventricular canal defect (CAVC)

In this condition, there is a hole in the center of the heart, between the top chambers (atria) and the lower chambers (ventricles). Instead of two separate atrioventricular valves connecting the upper and lower chambers, the heart has only one abnormally formed common valve. This defect allows extra blood to flow from the chambers on the left side of the heart into the chambers on the right side of the heart and back to the lungs. As a result, there is extra blood circulating between the heart and lungs, which makes the heart work too hard.

CAVC can cause the following symptoms, which are usually present within the first few weeks to months after your child is born:

  • Decrease in weight gain, possible weight loss
  • Fast breathing
  • Heart murmur 
  • Poor feeding
  • Tiring and sweating while feeding

Partial atrioventricular canal defect

In a partial atrioventricular canal defect, there is a hole between the top chambers of the heart (the atria). However, the valves between the top and bottom chambers of the heart are still abnormal. The mitral valve (on the left side) has a cleft in it. The cleft may allow blood to leak backwards though the mitral valve.  

Typically, a partial atrioventricular canal defect has fewer and less severe symptoms than a CAVC. In some cases, it causes no symptoms at all.


Sometimes an atrioventricular canal defect is diagnosed during pregnancy when an ultrasound examination is performed on the fetus’ heart. If we find an atrioventricular canal defect in utero, your obstetrician and our fetal cardiologist may suggest genetic testing since Down syndrome may be associated with the condition.

We may also diagnose atrioventricular canal defect after your child is born using some of the following procedures: 

  • Chest X-ray—an image that can show if your child’s heart is enlarged
  • Echocardiogram (also called an echo or cardiac ultrasound)—a safe, noninvasive procedure that uses ultrasound waves to create an image of the size, shape, and movement of your child’s heart, valves, and chambers along with how blood flows
  • Electrocardiogram (ECG or EKG)—a noninvasive procedure that shows electrical activity by placing stickers on your child’s chest

Treatments We Offer

Treatment for atrioventricular canal defects is surgical repair to close the holes and repair the valves. After we repair your child’s heart defect, it’s important that your child continue to get follow-up care with one of our pediatric cardiology specialists. We will monitor your child’s heart function and the status of the repair as your child grows. 

Surgery for complete common atrioventricular canal defect

To repair a CAVC, first our pediatric cardiac surgeon sews a patch into the hole between the left and right sides of the heart. Then the surgeon will carefully suspend the middle of the atrioventricular valve from this patch, taking care to ensure that the valve is functioning properly. 

We usually perform this surgery in the first year of life to avoid your baby’s developing complications such as heart failure or high pressure in the lungs.

Surgery for partial atrioventricular canal defect

For a partial atrioventricular canal defect, we perform a procedure to close the hole between the upper chambers of the heart and repair the left-side valve (mitral valve). As long as your child does not have symptoms, we can perform surgery later in childhood.

Why Choose Children’s Heart Center

Our pediatric cardiologists are experienced in treating complete atrioventricular canal defects with surgery to close the hole and repair the valves. Throughout your child’s care, we monitor the common atrioventricular canal defect. We will let you know if your child needs surgery and will explain the procedure to you. You can trust that you’re in the right place where we have the expertise to operate.

To ensure long-term health, your child will need lifelong follow-up care with one of our cardiologists trained in congenital heart disease. It’s our specialty.

We are here for you to help your child lead a long, healthy, and happy life.