Atrial Septal Defect (ASD)

What is an Atrial Septal Defect?

Sometimes referred to as a “hole in the heart,” atrial septal defect (ASD) is a congenital defect present at birth. If the defect is small, it may not cause serious health issues. If the defect is more significant and remains undetected into adulthood, there is often an increased risk of heart failure.


Atrial septal defect occurs during the development of the wall that separates the two upper chambers of the heart in the womb. The defect results in a space that allows blood to flow between these chambers.


Diagnosis starts with a physical exam to listen for a detectable heart murmur, which signifies that blood is not flowing properly. Heart tests will likely be performed to determine the presence of the deformity. If symptoms are minor, no treatment may be recommended.

What are the Symptoms of an Atrial Septal Defect?

Symptoms are not usually present in babies but are for adults age 30 and older.

Symptoms include

  • Heart palpitations
  • Recurring lung infections
  • Shortness of breath during strenuous activities
  • Heart murmur
  • Swelling in legs or feet
  • Abdominal swelling
  • Tiring easily

Atrial Septal Defect Causes

Heart defects that exist at birth (congenital) begin due to early issues in the development of the heart, but it is unclear exactly why the issues occur. Environmental and genetic factors could possibly be contributing factors.

If an atrial septal defect is present, blood that has been freshly oxygenated can move from the left atrium (left upper heart chamber) to the right atrium (right upper heart chamber). Once this occurs, the blood mixes with the blood that has not yet been oxygenated and is pumped through to the lungs, despite the fact that it has already been oxygenated.

The problem arises if the atrial septal defect is big; the lungs become overfilled due to the excess blood volume because the heart can be overworked. The right side of the heart can become weakened and enlarged if treatment does not occur. Blood pressure in the lungs also increases which can lead to pulmonary hypertension.

How is an Atrial Septal Defect Treated?

Treatment without surgery

Treatment without surgery involves the use of an ASD closure device. It is put in place with catheters (tubes) inserted via a small cut in the groin into a blood vessels that leads to the heart. The ASD device is then placed over the defect to prevent blood from passing between upper heart chambers.

Despite being present at birth, atrial septal defect isn’t often detected until later in life when signs become noticeable, with symptoms typically developing around the age of thirty. Prognosis depends on the degree of the deformity and when it is detected.

Treatment with surgery

If symptoms are noticeable and problematic, surgery is usually performed to repair the defect. When other heart defects are present with an ASD, open surgery may be necessary.

Atrial Septal Defect Prevention

Unfortunately, atrial septal defects usually cannot be prevented. As the diagnosis can be congenital, those who are trying to become pregnant should take careful measures. A preconception visit with a family physician should be scheduled.

Which will include the following precautions:

  • Testing for rubella immunity, or rubella vaccination
  • Reviewing current medications and health conditions
  • Monitoring of any health problems
  • Reviewing medical history of family

It is important to monitor health issues carefully during pregnancy. A physician may recommend stopping or may adjust dosage for certain medications while pregnant.

If there is a history of heart defects in the family, a genetic counselor can help determine any potential risks before conception.

Although these methods are somewhat effective in preventing atrial septal defect, some cases may require surgery or the use of a catheter. Occasionally, drug therapy can help cases with atrial arrhythmias or substantial volume overload.

Last Reviewed:
September 13, 2016
Last Updated:
November 10, 2017