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Atrioventricular Canal Defect (AVC)


Atrioventricular canal (AV canal, endocardial cushion defect) is present at birth and includes:

  • An atrial septal defect (ASD) low in the atrium (called a primum ASD)
  • A ventricular septal defect (VSD) high in the ventricle
  • A common atrioventricular valve (instead of two separate valves, the mitral and tricuspid valves)

Atrioventricular canal defect occurs when the center of the heart does not form properly. The condition varies in severity. Some infants will only have mild symtoms while others may have difficulty growing and gaining weight. The symptoms are commonly those of congestive heart failure. Most children undergo surgery between 3-6 months to patch the septal defects and repair the atrioventricular valve.

Normal heart – in a healthy heart with proper blood flow, the blue droplets representing oxygen-poor blood travel to the lungs, and the red oxygen-rich droplets circulate through the body.

A heart with atrioventricular canal defect (AVC).


Surgery is the treatment for atrioventricular canal defect. The common valve in AVC does not have all the normal leaflets of both a tricuspid and mitral valve so the surgeon must create the best possible valves from the tissue present. The goal is no narrowing and minimal leak of the two valves.

Surgery for atrioventricular canal defect includes:

  • General anesthesia
  • Opening the chest in the center
  • Using cardiopulmonary bypass
  • Closing the VSD hole
  • Repair the valves and then
  • Close the ASD hole

A heart with atrioventricular canal defect (AVC).

Surgical repair of atrioventricular canal defect.