Atrial Septal Defect

Atrial septal defects (ASDs) are one of the most common congenital heart defects in which the septum that separates the left and right atria (upper chambers of the heart) does not close following development, leaving an opening and potentially allowing blood to leak between the two chambers.

About an Atrial Septal Defect

Your child’s heart forms in the first eight weeks of fetal development when the fetus is no bigger than a kidney bean. During fetal development, the heart begins as a hollow tube before developing partitions that create the four chambers of the heart. An atrial septal defect (ASD) is a congenital condition that causes children to be born with an opening in the wall that divides the upper two chambers (atria) of the heart. The wall (atrial septum) separates oxygen-rich blood traveling to the body from oxygen-depleted blood returning to the lungs. A hole in the atrial septum allows the oxygen-rich and oxygen-poor blood to mix and affects how the heart and lungs develop.

Left untreated, an ASD can cause right ventricular dilation over time. Blood passes through the hole from the left atrium to the right atrium where the oxygenated blood then mixes with the oxygen-poor blood in the right atrium. The right atrium then pushes more blood than normal through the pulmonary artery into the lungs. Long-standing extra volume of blood eventually causes right ventricular dilation and raises the pressure in the lungs. This may cause your child to be at higher risk of having a stroke as an adult.

The exact cause of atrial septal defects is not known but some defects may be genetic in origin. Others may be affected by conditions during pregnancy. Females are more likely than males to have an atrial septal defect.

Symptoms of an Atrial Septal Defect

Most children who have an ASD do not have any symptoms, especially if the defect is small. A larger defect can overwork the right side of the heart and lungs, causing a variety of symptoms that resemble other conditions. Speak with your child’s doctor or make an appointment with a pediatric cardiologist if any heart abnormalities are suspected.

Common symptoms of an ASD may include:

  • Abnormal heart rhythm or beat
  • Difficult and rapid breathing or shortness of breath
  • Fatigue
  • Frequent respiratory infections
  • Migraines in older children
  • Slow growth
  • Stroke from a blood clot
  • Sweating
  • Tiring easily while playing or exercising

Diagnosing an Atrial Septal 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 increased blood flow in the right atrium, a recommendation to see a pediatric cardiologist may be made.

Tests performed when diagnosing an ASD may include:

  • Cardiac MRI or CT Scan: A cardiac MRI or CT scan is used to take more detailed images of the heart to help define the anatomy and detect anomalies.
  • 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 Atrial Septal Defect

As a child grows, small ASDs may close on their own, without treatment, during infancy or early childhood. Your pediatric cardiologist may recommend monitoring your child’s heart, then repairing the hole if it doesn’t close on its own. Medication may be prescribed to lessen symptoms and help reduce the effects of an ASD. To repair an ASD, a pediatric heart surgeon or interventional cardiologist patches or plugs the hole via open-heart surgery or cardiac catheterization.

Treatment options for an ASD 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 to plug the hole.
  • Open-Heart Surgery: During open-heart surgery, a patch is placed directly to close the hole.

After an initial recovery and restricted activity period, your child should be able to resume their daily routine. Follow-up appointments may be recommended to monitor your child’s health whether the defect was repaired or closed on its own.

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

Baby sleeping after heart surgery

Texas Center for Pediatric and Congenital Heart Disease

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