Atrioventricular canal defect

Atrioventricular canal defect is a combination of several abnormalities in the heart present at birth (congenital abnormalities). This defect, which is sometimes called endocardial cushion defect or atrioventricular septal defect, occurs when there's a hole between the chambers of the heart and problems with the valves that regulate blood flow in the heart.

Atrioventricular canal defect allows extra blood to circulate to the lungs. Ensuing problems overwork the heart and cause it to enlarge.

Atrioventricular canal defect is often associated with Down syndrome. If left untreated, atrioventricular canal defect may cause heart failure and high blood pressure in the lungs. To fix this defect, doctors often recommend surgery during the first year of life to close the hole and reconstruct the valves.

Symptoms Causes Risk factors Complications Prevention

There are two common types of atrioventricular canal defect — partial and complete. The partial form involves only the two upper chambers of the heart. The complete form allows blood to travel freely among all four chambers of the heart. In either type, extra blood circulates in the lungs.

Complete atrioventricular canal defect

Signs and symptoms of complete atrioventricular canal defect usually develop in the first several weeks of life. They include:

  • Difficulty breathing (dyspnea)
  • Lack of appetite
  • Poor weight gain
  • Bluish discoloration of the lips and skin (cyanosis)

If your baby has complete atrioventricular canal defect, he or she may also develop signs and symptoms of heart failure, including:

  • Fatigue
  • Wheezing
  • Swelling (edema) in the legs, ankles and feet
  • Sudden weight gain from fluid retention
  • Excessive sweating
  • Decreased alertness
  • Irregular or rapid heartbeat

Partial atrioventricular canal defect

Signs and symptoms of a partial atrioventricular canal defect may not appear until early adulthood. When they do become noticeable, signs and symptoms may be related to complications that develop as a result of the defect, and may include:

  • Abnormal heartbeat (arrhythmia)
  • Heart valve problems
  • Heart failure
  • High blood pressure in the lungs (pulmonary hypertension)

When to see a doctor

Contact your doctor if you or your child develops any of the following signs or symptoms. These could be indications of heart failure or another complication of atrioventricular canal defect:

  • Poor appetite
  • Failure to gain weight, in infants and children
  • Shortness of breath
  • Easily tiring
  • Swelling of the legs, ankles or feet
  • Bluish discoloration of the skin

Some babies with the partial form of atrioventricular canal defect may not have any signs or symptoms for weeks, months or even years, depending on the severity of the defect. But, anytime the signs or symptoms above start to appear, seek medical care.

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