Atrial Septal Defect

(ASD; “Hole” in the Heart)

Pronounced: AY-tree-uhl SEP-tull DEE-fect


An atrial septal defect (ASD) is a hole in heart. It is in the wall between the left and right upper chambers of the heart. Blood can flow through this hole. This will make it hard for the heart to work well. It can also lead to a backup of fluids in the lungs.

Heart Chambers and Valves
heart anatomy

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ASD happens as the baby grows in the uterus. It is not always known why the wall does not grow as it should. Factors that may play a role include:

  • Changes in certain genes—may occur on their own or be passed down from parent
  • Illness during the mother’s pregnancy

Risk Factors

The chances of ASD are higher if the mother:

  • Used tobacco, alcohol, or antidepressants during pregnancy
  • Has diabetes
  • Has elevated blood glucose
  • Is 35 years of age or older


Small holes may not cause immediate symptoms. They may cause problems once the child is more active in later life. Symptoms caused by ASD may include:

For older children and adults:

  • Tiring easily
  • Difficulty doing physical activity
  • Irregular heart beat— arrhythmia
  • Fast heart beat— tachycardia
  • Breathing problems
  • Fainting
  • Fluid buildup in the lower legs and ankles
  • Bluish tint to skin, lips, or fingernails

For babies (rare):

  • Fast heart beat
  • Problems gaining weight
  • Repeated lung infections


The doctor will ask about symptoms and past health. A physical exam may be done. The doctor may hear a murmur while listening to the heart.

The doctor may suspect ASD based on symptoms. An echocardiogram can confirm the diagnosis.

ASD can make the right side of the heart larger. This can lead to other health issues. To look for changes to the heart your doctor may also do the following:


Not all ASD will make the heart and lungs work harder. These may not need treatment. The heart will be checked during checkups for any changes. Your care team will look for any changes in heart size or abnormal heart rhythms. ASD in infants may close on their own by 3 to 5 years of age.

ASD with heart changes may need to limit certain activity. Those with smaller holes or no effects on the heart can often do all activities.

Holes that are causing stress to the heart and lungs will need treatment. The hole will be sealed with surgery or a device. Options include:

  • Percutaneous procedure:
    • A tube is inserted into a blood vessel in the thigh. It is passed up to the heart. Large incisions are not needed.
    • A plug is passed up to the heart. Once in place it seals the hole in the heart.
  • Open surgery:
    • Requires incision to access the heart.
    • May be needed for large holes. Holes may also be located in an area that affects other structures like valves.


There is no way to prevent ASD since the cause is unknown.


American Heart Association

Family Doctor—American Association of Family Physicians


Canadian Adult Congenital Heart Network

Heart and Stroke Foundation


Atrial septal defect. Kids Health—Nemours Foundation website. Available at: Updated September 2016. Accessed July 25, 2018.

Atrial septal defect (ASD). American Heart Association website. Available at: Updated January 19, 2018. Accessed July 25, 2018.

Atrial septal defects. EBSCO DynaMed Plus website. Available at: Updated December 27, 2017. Accessed July 25, 2018.

Last reviewed May 2018 by EBSCO Medical Review Board Michael J. Fucci, DO, FACC  Last Updated: 7/25/2018