Atrial Septal Defect (ASD)

An atrial septal defect (ASD) occurs when the wall (septum) between the right atrium and the left atrium does not develop properly, leaving a hole that is present at birth.

If the opening is large (greater than 2 centimeters), oxygen-rich blood from the left atrium goes back into the right atrium, rather than out to the body. A large ASD makes the heart work harder to deliver oxygen-rich blood to support your body’s functions. This extra effort can enlarge and weaken the right side of the heart.

Some individuals only learn they have an ASD when they have an ultrasound for some other medical condition.

ASD Symptoms and Risks

Patients with large ASDs may experience:
  • Shortness of breath — especially when active
  • Fatigue
  • Feeling faint (syncope)
  • Heart arrhythmia (irregular or abnormal heart beats) including atrial fibrillation (an irregular and often fast heartbeat in the upper chambers of the heart) 
  • Heart failure (a condition in which the heart can’t pump as well as it should, limiting the amount of blood available to support the body’s functions. Also known as congestive heart failure.)
  • Heart murmur  (an unusual sound between heart beats that may be due to a defect in the heart’s wall or a damaged valve)

If you have symptoms of an ASD, your primary-care doctor may order an echocardiogram, and refer you to the specialists at the Structural Heart and Valve Disease Program at the Swedish Heart & Vascular Institute (SHVI).

Closing an ASD

The Structural Heart and Valve Disease team will use advanced imaging to confirm the diagnosis and determine the best treatment options. If the ASD is small and only a small amount of blood is moving between the atria, your cardiologist may recommend monitoring your condition.

If, on the other hand, your symptoms are significant and the ASD is large enough to affect blood flow in the right side of your heart, your cardiologist will talk with you about procedures that are available at Swedish to close the opening.

Catheter-based procedure: During this procedure, you will be under conscious (twilight) sedation. Using a local anesthetic, your cardiologist will make a small incision in your groin and then thread a catheter through a vein and up to your heart and the area where the hole is located. Your doctor will then use the catheter to deliver the closure device. Over time, your own tissue will grow over the device, making it permanent.

Before, during and after the procedure, your cardiologist will rely on advanced imaging to determine the location and size of the opening, as well as proper placement of the device.

The closure procedure takes about one hour. Most patients remain overnight in the hospital after an ASD closure procedure.


Atrial septal defect closure device.

Open-heart surgery: If a catheter-based procedure cannot be performed, open-heart surgery may be an option. This surgery is performed while you are under general anesthesia. The surgeon will make an incision in your chest and connect your heart to a heart-lung machine, so your blood will continue to circulate throughout the procedure. The surgeon will use a patch or stitches to close the hole in the septum. After surgery, patients typically spend two to three days in the hospital.

For more information about open-heart surgery to repair an atrial septal defect, go to Swedish Cardiac Surgery >