Atrial Septal Defect (ASD)

What is an atrial septal defect (ASD)?

An atrial septal defect (ASD) is a hole in the heart wall that separates the upper right and left chambers of the heart, called the atria. An ASD is a condition that a baby is born with (congenital).

An ASD allows oxygen-rich (red) blood to pass from the left heart chamber and mix with oxygen-poor (blue) blood in the right chamber. Over time, this can cause the heart and lungs to work harder and put the child at risk for other conditions including:

The size of the hole can vary from small to large. Some ASDs close on their own over time, usually during the first three years of life. However, if the hole remains large, it will need to be closed using cardiac catheterization or minimally invasive surgical techniques.

What are the symptoms of an ASD?

Most children with an ASD do not have any symptoms. Often, they are referred to a cardiologist because of a heart murmur picked up by their pediatrician.

If a child does have symptoms they can include:

  • decreased endurance
  • slow growth
  • frequent respiratory infections

What causes an ASD?

Most atrial septal defects occur by chance, with no clear reason. All babies have an opening between the upper two heart chambers before birth that usually closes in the first weeks or months after birth. In some cases, this opening is larger than average, or does not close on its own.

How is an ASD diagnosed?

An atrial septal defect is often first detected when a doctor hears a heart murmur when listening to your baby’s heart. Sometimes, an ASD is not diagnosed for many years.

Depending on the type of murmur your doctor hears, they may recommend one or more or the following tests:

How is an ASD treated?

A small ASD may need no treatment. Your child’s doctor may recommend closing an ASD if it is large or if is causing symptoms or problems. Treatment options may include:

  • Cardiac catheterization: For this non-surgical procedure, an umbrella-shaped device is inserted into the heart through the leg vein with a catheter, a long, thin tube. Once in the right spot, it is opened to cover the hole with a patch.
  • Surgery: If the ASD is too large or in an area where a catheterization will not work, surgery may be needed to stitch or patch the hole closed. The surgeons at Boston Children’s Hospital can perform minimally invasive surgical ASD closure, so the scar is smaller and the recovery faster.

How we care for atrial septal defects

The Heart Center at Boston Children’s Hospital is experienced in diagnosing and treating all types of congenital heart problems, including atrial septal defects. Depending on the size of your child’s ASD, our clinicians may be able to use non-surgical catheter-based techniques to close the hole, avoiding surgery.