An atrial septal defect (ASD) is a hole in the septum, or wall, that separates the two upper chambers of the heart, called the atria. An atrial septal defect allows oxygen-rich blood (returning to the left atrium from the lungs) to mix with oxygen-poor blood (returning to the right atrium from the body).

An ASD forms when the heart is developing, very early in pregnancy. We don't yet understand what causes the heart to develop abnormally. Sometimes ASDs occur as part of a genetic syndrome, but most happen in patients with no other medical problems. Our team of pediatric cardiologists works closely with our clinical geneticists to explore all the possibilities if there is concern for a genetic syndrome.

ASDs vary in size and shape. Children with smaller defects may have no symptoms, while children with larger defects may have signs of poor growth and congestive heart failure. ASDs, even small defects, may be recognized by a physician or medical provider during a physical examination. Providers may recognize an extra heart sound (called a murmur) or an abnormal second heart sound. The defect will create a murmur as extra blood entering the right side of the heart crosses the normal valves of the heart, creating turbulence.

Children suspected to have an ASD are often referred to a pediatric cardiologist. If the physician suspects that your child has an ASD, he or she will undergo an echocardiogram, which is an ultrasound that looks at the structure of the heart, and an electrocardiogram (ECG), which looks at the electrical activity of the heart.

How could an ASD affect my child?

If an ASD is small, it may have no affect on your child and may even close by itself over time. Larger ASDs allow a lot of blood to cross from the left side to the right side of the heart. This can cause the right side of the heart to stretch out and sends extra blood to the lungs. Over time, this can lead to pulmonary hypertension (high lung pressures), arrhythmia (abnormal heart rhythm) or congestive heart failure. These conditions do not usually develop until later in life.

The extra blood flow to the lungs may also predispose a child to lung infections or poor growth. If necessary, ASDs are typically repaired in children between 3 and 5 years of age. Infants and older children may also undergo the repair.

Treating Atrial Septal Defect

Children with ASDs are monitored regularly by pediatric cardiologists. If they develop symptoms of congestive heart failure, recurrent, unexplained lung infections, or have poor weight gain, they may need to have the ASD repaired. Children with ASDs that are large and cause the right side of the heart to stretch out usually undergo repair to prevent future symptoms.

View our pediatric cardiac surgery outcomes.

Until recently, all ASDs were closed by open heart surgery. The Children's Heart Program offers a minimally invasive treatment for some ASDs. Our pediatric cardiologists are trained to close ASDs by using a catheter-based approach. This is done by placing catheters in the blood vessels that lead to the heart (cardiac catheterization). A mesh device that can be placed using these catheters closes the ASD permanently. Some ASDs cannot be closed this way and require surgery.

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

Following catheter-based closure of the ASD, your child will take aspirin for six months. Your child may also require antibiotics prior to dental procedures for six months. However, most children do not require long-term therapy. Some children require a diuretic medicine for a few weeks or more after ASD closure.

Most children resume a normal lifestyle without restriction approximately six weeks after surgery.

Most children whose ASDs are closed early in life have no complications. Some will have heart rhythm troubles even after ASD closure.

To make an appointment with a Children's Heart Program physician, please call 410-328-4348.

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