An atrial septal defect (ASD) is a hole in the wall (septum) that separates the two upper chambers of the heart, called the atria. This hole allows blood with oxygen to mix with blood that has little oxygen.

If the hole is small, there may be no effect on your child. The hole may even close over time. If the hole is large and sends extra blood to the lungs, your child may experience pulmonary hypertension, abnormal heart rhythm or congestive heart failure.

We do not know the cause of ASD. It can form when the heart is developing early in the pregnancy or later in life. Sometimes ASD occurs as part of a genetic syndrome, but most ASD conditions happen in patients with no other medical problems.


If your child has a heart murmur or abnormal heartbeat, your child may have an echocardiogram done to look at the heart structure and an electrocardiogram (ECG) to look at the electrical activity of the heart. 

ASDs are repaired in infants, as well as children between 3 and 5 years of age. Older children may also need surgery for ASD.

Care Providers

The University of Maryland Children's Heart Program team that treats ASD includes a pediatric cardiac surgeon, pediatric cardiologists, pediatric and neonatal intensive care doctors and nurses, pediatric cardiac anesthesiologists, cardiac operating room staff, cardiac nurses and many others with expertise in providing this specialized cardiac care. 

Our team of pediatric cardiologists also works closely with our clinical geneticists to explore all the possibilities if there is concern for a genetic syndrome.

Treating Atrial Septal Defect

Children with ASDs are monitored regularly by pediatric cardiologists. If they develop symptoms of congestive heart failure, recurrent and unexplained lung infections or have poor weight gain, they may need to have the ASD repaired. 

The Children's Heart Program offers a minimally invasive treatment for some cases of ASD and surgery for other cases. Our pediatric cardiologists can close an ASD with a catheter-based approach and by using a mesh device. Some cases of ASD cannot be closed this way and require open heart surgery.

Your child may remain in the hospital between one and four days following surgical or catheter-based intervention. Your child will also be seen by the pediatric cardiologist in the outpatient clinic for follow-up visits. The frequency of these clinic visits decreases over time.

Following catheter-based closure of the ASD, your child will take aspirin for six months and may require antibiotics prior to dental procedures for six months. Some children need to take a diuretic medicine for a few weeks or more after ASD closure.

Contact Us 

  • To learn more about Maternal Fetal Heart medicine, please call 410-328-3865.
  • To make an appointment with a Children's Heart Program physician, please call 410-328-4348.