Atrioventricular Canal Defect

An atrioventricular canal defect, also known as an endocardial cushion defect or an atrioventricular septal defect, is a complex congenital heart defect that can involve more than one abnormality. This condition results from a hole in the center of the heart and compromises heart function.

About an Atrioventricular Canal Defect

An atrioventricular canal defect happens early in pregnancy as the heart develops from a hollow tube and grows partitions that evolve into the four chambers. If the structure doesn’t form properly, an atrioventricular canal defect can occur and may involve more than one abnormality.

Atrioventricular canal defect abnormalities may include:

  • Abnormal Valves: A malformation of the mitral and/or tricuspid valves that separate the chambers of the heart, which can affect how the heart works.
  • Atrial Septal Defect: An opening in the wall between the upper chambers (atria) of the heart.
  • Ventricular Septal Defect: An opening in the wall between the lower chambers (ventricles) of the heart.

A hole or improperly shaped valve allows oxygenated blood to mix with oxygen-depleted blood returning from the body, or permits blood to flow or leak backward. More blood than normal can pass through one side of the heart, causing the other side to become enlarged and the lungs to work harder to process more blood at one time. Your child may breathe faster than normal because extra blood being pumped in the lungs causes higher pressure to occur in the blood vessels in the lungs.

The risk of being born with an atrioventricular canal defect is higher in individuals with Down syndrome. Left untreated, an atrioventricular canal defect can cause congestive heart failure and high blood pressure in the lungs. Eventually, the blood vessels in the lungs thicken, putting your child at risk for vascular disease and potentially causing irreversible damage.

Symptoms of an Atrioventricular Canal Defect

Atrioventricular canal defect symptoms may resemble other conditions. Speak with your child’s doctor or make an appointment with a pediatric cardiologist if any abnormalities are suspected. Atrioventricular canal defect symptoms can affect children differently, but symptoms typically become noticeable during infancy.

Symptoms of an atrioventricular canal defect may include:

  • A blue or purple color in the lips, skin, and nails (cyanosis)
  • Disinterest in feeding, trouble feeding, or tired while feeding
  • Heart murmur
  • Pale, cool skin
  • Poor weight gain and growth
  • Sweating
  • Tiredness
  • Trouble breathing or rapid, heavy breathing

Diagnosing an Atrioventricular Canal Defect

During physical examinations, your child’s doctor listens to your child’s heart and lungs and may detect a heart murmur, which are extra sounds heard throughout the cardiac cycle due to increased blood flow. If your pediatrician suspects abnormal blood flow, a recommendation to see a pediatric cardiologist may be made.

Tests performed when diagnosing an atrioventricular canal defect may include:

  • Cardiac Catheterization: During cardiac catheterization, a small catheter (thin tube) is inserted into a larger blood vessel, typically in the groin, and guided to the heart where blood pressure and oxygen measurements can be taken in the aorta and pulmonary artery as well as the four chambers of the heart. A dye can also be injected through the tube to make the heart’s structure more visible on an X-ray.
  • Chest X-Ray: A chest X-ray produces an image of the tissue and bones in the heart and lungs and helps your provider assess the shape, size, and structure of the heart and lungs as well as the aeration of or any congestion in the lungs.
  • Echocardiogram: An echocardiogram uses ultrasound technology to create a moving image of the heart and its valves, allowing your provider to assess the structure and function of the heart. An echocardiogram also helps provide information about blood flow and how well the heart is pumping blood.
  • Electrocardiogram (ECG or EKG): An electrocardiogram uses electrodes that are placed on the body to record the electrical activity taking place in the heart. An ECG/EKG test helps detect abnormal rhythms, such as cardiac arrhythmias, stress on the heart, and damage to the heart muscles.

Treating an Atrioventricular Canal Defect

Treatment plans can vary based on your child’s age, health, and medical history as well as the level of atrioventricular canal defect and symptoms. Your pediatric cardiologist may manage your child’s condition initially with medication to help the heart and lungs function better and recommend high-calorie formula or breast milk or supplemental tube feedings to help your baby get adequate nutrition until the defect can be repaired.

Pediatric heart surgeons recommend treatment before the baby turns six months old to surgically repair the hole and valves if necessary. To repair an atrioventricular canal defect, a permanent patch can be placed over the holes and the improperly formed valves can be partitioned.

After resting and recuperating, your child should go on to live a healthy life with no activity restrictions. Ongoing care may be recommended to ensure your child’s heart and lungs continue to function well.

Care Team Approach

The Texas Center for Pediatric and Congenital Heart Disease, a clinical partnership between Dell Children’s Medical Center and UT Health Austin, takes a multidisciplinary approach to your child’s care. This means your child and your family will benefit from the expertise of multiple specialists across a variety of disciplines. Your care team will include pediatric cardiologists, cardiothoracic surgeons, interventional cardiologists, critical care specialists, hospitalists, anesthesiologists, perfusionists, nurses, advanced practice providers, social workers, psychologists, child life specialists, dietitians, physical and occupational therapists, pharmacists, and more, who work together to provide unparalleled care for patients every step of the way. We collaborate with our colleagues at the Dell Medical School and The University of Texas at Austin to utilize the latest research, diagnostic, and treatment techniques, allowing us to identify new therapies to improve treatment outcomes. We are committed to communicating and coordinating your child’s care with referring physicians and other partners in the community to ensure that we are providing comprehensive, whole-person care.

Learn More About Your Care Team

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Texas Center for Pediatric and Congenital Heart Disease

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