What is an atrioventricular canal defect in a child?

An atrioventricular (AV) canal defect is a congenital heart defect. This means that your child is born with it. AV canal defect is a large hole in the center of the heart. It is caused by a combination of problems with the heart's structure.

• Atrial septal defect. This is an opening in the wall (septum) between the 2 upper chambers of the heart. These are called the right and left atria.

• Ventricular septal defect. This is an opening in the wall between the 2 lower chambers of the heart. These are called right and left ventricles.

• Improperly formed mitral or tricuspid valves.  This is when the valves that separate the upper heart chambers from the lower heart chambers aren’t formed right.

Other heart problems such as tetralogy of Fallot (TOF) and transposition of the great arteries (TGA) also commonly occur.

There are several types of this heart defect depending on how broad the defect is. These conditions cause oxygen-rich (red) blood and oxygen-poor (blue) blood to mix. This sends extra blood to your child's lungs.

What causes an AV canal defect in a child?

Genes and family history may play a part in AV canal defects. AV canal defects are often linked to Down syndrome or other chromosome problems.

What are the symptoms of an AV canal defect in a child?

The symptoms of AV canal defect may be similar to symptoms caused by other heart problems.

Babies with AV canal defects often have symptoms. They can include:

• Tiredness

• Sweating

• Pale, cool skin

• Fast, heavy breathing

• Fast heart rate

• Chest congestion

• Trouble feeding

• Not enough weight gain

Your child’s symptoms depend on the size of their septal openings. The larger the openings, the more blood is able to pass through them. This can overload your child's heart and lungs. This means that your child’s symptoms may be more severe.

Over time, the pressure in your child’s lungs will force blood back to their heart. This blood has low oxygen levels, and it’s sent to the rest of the body. This causes your child’s lips, nail beds, and skin to turn blue (cyanosis).

How is an AV canal defect diagnosed in a child?

Your child may be diagnosed by ultrasound during pregnancy. Or your child's healthcare provider may first suspect a heart defect when they hear an abnormal sound (heart murmur) when listening to your child's heart with a stethoscope. Your child may also have symptoms of a heart problem. Your child’s healthcare provider may refer your child to a heart care provider for children (pediatric cardiologist).

The heart care provider will check your child and listen to their heart and lungs. The location and loudness of the murmur will help the provider make the diagnosis.

Your child’s healthcare provider may then do tests to confirm the diagnosis. The tests your child has depend on their age and condition, and the provider's preferences.

How is an AV canal defect treated in a child?

Treatment will depend on your child’s symptoms, age, and general health. It will also depend on how severe the condition is.

All children with an AV canal defect will need to have surgery to fix it. They may also need other treatments.

What are possible complications of an AV canal defect in a child?

If left untreated, an AV canal defect can cause several problems.

How can I help my child live with an AV canal defect?

All children with an AV canal defect will need to have surgery to repair it. Before surgery, it’s important to follow the advised medicine and feeding schedules.

Many children who have had an AV canal defect will live active, healthy lives after their surgery. Their activity levels, appetite, and growth will return to normal over time. Some children will still have heart valve problems after surgery. They may eventually need another surgery to repair or replace the leaky or blocked valve or valves. Ask your child's healthcare provider about your child’s outlook.

Key points about an AV canal defect in children

• An AV canal defect is a heart problem that children can be born with.

• Children with an AV canal defect need to have surgery to repair it.

• Many children who have had an AV canal defect will live active, healthy lives after their surgery.

Next steps

Tips to help you get the most from a visit to your child’s healthcare provider:

• Know the reason for the visit and what you want to happen.

• Before your visit, write down questions you want answered.

• At the visit, write down the name of a new diagnosis and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you for your child.

• Know why a new medicine or treatment is prescribed and how it will help your child. Also know what the side effects are.

• Ask if your child’s condition can be treated in other ways.

• Know why a test or procedure is recommended and what the results could mean.

• Know what to expect if your child does not take the medicine or have the test or procedure.

• If your child has a follow-up appointment, write down the date, time, and purpose for that visit.

• Know how you can contact your child’s provider after office hours and on weekends and holidays. This is important if your child becomes ill and you have questions or need advice.