Atrial septal defect is a congenital heart defect in which the wall that separates the upper heart chambers, called atria, does not close completely. This defect may be congenital and present at birth.

In fetal circulation, there is normally an opening between the two upper chambers of the heart to allow blood to bypass the lungs. This opening usually closes around the time a baby is born. If the atrial septal defect is persistent, blood continues to flow from the left to the right atria. This is called a shunt. If too much blood moves to the right side of the heart, pressure builds up in the lungs. The shunt can be reversed so that blood flows from right to left. Many problems can occur if the shunt is large, but small atrial septal defects often cause very few problems and may be found only much later in life.

Atrial septal defect is not very common. When a person has no other congenital defect, symptoms may be absent, particularly in children. Symptoms may begin anytime from birth through childhood. Individuals with atrial septal defect are at an increased risk of developing a number of complications, including:

  • Atrial fibrillation (in adults)

  • Heart failure

  • Pulmonary overcirculation

  • Pulmonary hypertension

  • Stroke


Small- to moderate-sized defects may produce no symptoms or may not be detected until middle age or later. Symptoms may include:

  • Difficulty breathing

  • Frequent respiratory infections in children

  • Sensation of feeling the heartbeat (palpitations) in adults

  • Shortness of breath with activity


An atrial septal defect (ASD) may not require treatment if there are few or no symptoms or if the defect is small. Surgical closure of the defect is recommended if the defect is large, the heart is swollen, or other symptoms occur. The procedure to close the defect without surgery involves placing a closure device into the heart through tubes called catheters. The closure device is then placed across the ASD, and the defect is closed. Not all patients with ASD can have this procedure.

Texas Health is committed to providing quality care to heart and vascular patients throughout North Texas and beyond. While various technologies and services are discussed here, not all of our hospitals offer every treatment and diagnostic technology highlighted. Call 1-877-THR-WELL to learn more about heart and vascular services at a Texas Health hospital near you.

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