Atrioventricular canal (AVCD or AV canal defect) is a combination of heart defects that are present at birth (congenital). AVCD occurs when the fetal heart doesn’t develop properly during the first two months of pregnancy. The result is several related abnormalities of the heart’s structure, including:

• Atrial septal defect: An opening in the wall between the two upper chambers of the heart (atrial septum).
• Ventricular septal defect:  An opening in the wall between the two lower chambers of the heart (ventricular septum).
• Improperly formed mitral and/or tricuspid valves: The valves that separate the upper heart chambers (atria) from the lower heart chambers (ventricles) are not correctly formed. This may mean there is one common valve or two abnormally formed valves between the upper and lower chambers.

Congenital heart disease is present in 50 percent of children born with Down syndrome and roughly 45 percent of these cases have atrioventricular canal defect.  

Specific atrioventricular canal treatment will be determined by your child's doctor based on:

• Your child's age, overall health and medical history
• Extent of the disease
• Your child's tolerance for specific medications, procedures or therapies
• Expectations for the course of the disease
• Your opinion or preference.

AV canal defect is treated by surgical repair. However, medical support may be necessary until the operation is performed. Treatment may include:

Medical Management 
Many children will eventually need to take medications to help the heart and lungs work better.

Surgical Repair
The goal is to repair the defect before the lungs become damaged from too much blood flow and pressure.

The atrial and ventricular septal defects are often closed with a patch. The patch is either made from the membrane that covers the outside surface of the heart or from artificial material. The valve repair technique will depend on the defect and the surgeon's preferences.