Atrial Septal Defect

Nemours Cardiac Center at Nemours/Alfred I. duPont Hospital for Children

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Children’s heart conditions can’t be prevented, but a lot can be done to improve and often completely repair their hearts at any age. Thanks to advanced technology and the pediatric heart experts at the Nemours Cardiac Center (based at Nemours/Alfred I. duPont Hospital for Children), most children born with a heart problem — even newborns only hours or days old — can be quickly diagnosed and treated right when it matters the most. At the Cardiac Center, we specialize in early detection and repair of congenital heart defects (also often called, “congenital heart disease”).

If your child’s been diagnosed with an atrial septal defect (or “ASD,” for short), a very common heart defect, we’re here to ease your concerns, answer your questions, and repair the problem. At the Nemours Cardiac Center, we take every child’s condition we treat very seriously. But of all of the conditions we see, ASDs are some of the most straightforward problems we fix. We’re experts in diagnosing and repairing them, and getting children back to doing what they do best — being kids.

What Is It?

An atrial septal defect (ASD) is a hole in the atrial septum — the wall between the right and left atria. (The top two chambers of the heart are, collectively, called the “atria.” A single chamber is called an “atrium.”)

With atrial septal defects, blood flows from the higher-pressure left atrium to the lower-pressure right atrium. When this happens, the oxygen-rich blood of the left atrium is redirected through the right side of the heart and back to the lungs. The right atrium, the right ventricle (one of the heart’s two lower chambers that receive blood from the atria) and the pulmonary artery (the large artery that receives blood from the right ventricle and carries it to the lungs) may enlarge because of the increased blood flow through these structures.

The long-term side effects of untreated atrial septal defects include:
  • heart rhythm abnormality (called “atrial arrhythmias”)
  • problems with the function of the ventricles (called “ventricular dysfunction”)
  • thickening of the pulmonary arteries due to high blood flow (called “pulmonary vascular obstructive disease”)

For these reasons, it’s best to close most atrial septal defects to prevent complications later in life.

Types of Atrial Septal Defects

There are three types of ASDs:

  1. Secundum-Type ASD: This is the most common, making up about 85 percent of all ASDs. In a secundum-type ASD, the hole is located in the central part of the atrial septum.
  2. Primum-Type ASD: Primum-type ASDs make up between 5–10 percent of all ASDs. In a primum-type ASD, the hole is located in the lower part of the atrial septum. Frequently, abnormalities of one or more heart valves (most often the mitral valve) are associated with this defect (which also may be called a “partial atrioventricular septal defect” or “partial atrioventricular canal”). Unlike the secundum-type ASD, children with primum-type ASD have symptoms in early childhood. Surgery is the only method of treatment for a primum-type ASD because there’s no chance of the hole closing on its own.
  3. Sinus Venosus ASD: Sinus venosus atrial septal defects make up 5–10 percent of all ASDs. In a sinus venosus ASD, the hole is located in the upper portion of the atrial septum. This type of ASD is often associated with abnormal (“anomalous”) drainage of the right, upper pulmonary veins. This means that the pulmonary veins, which normally carry oxygenated blood from the lungs to the left atrium, drain into the right atrium instead. There’s no chance that this type of ASD will close on its own, so a surgical repair is necessary.

How Does the Heart Normally Work?

When your child has a congenital heart defect, there’s usually something wrong with the structure of the heart. In order to understand your child’s condition, it can help to know how the heart should work normally.
Learn More About Normal Cardiac Anatomy »

Nemours’ experts at also offer these helpful resources to help both you and your child understand how the heart works:

How & When Is It Diagnosed?

In many cases, infants and young children are asymptomatic (meaning, they don’t have any symptoms), so the atrial septal defect (ASD) may not be detected until they’re school age or older. Approximately 20 percent of secundum-type ASDs close spontaneously on their own by the time children turn a year old.

If an atrial septal defect (ASD) is suspected, it’s usually because a physician hears a heart murmur by listening with a stethoscope. (A heart murmur is a noise that occurs as blood flows through the heart. Some murmurs can be heard in children with normal hearts. Others may indicate a structural abnormality that may or may not be serious.) A heart murmur from an atrial septal defect (ASD) is associated with an increase in blood flow across the pulmonary valve (the heart valve between the right ventricle and the pulmonary artery that consists of three flaps or “cusps”).

Using an echocardiogram (or “echo,” for short), our Nemours Cardiac Center pediatric heart experts can confirm an atrial septal defect (ASD) diagnosis and identify the specific type of ASD. An echo is a completely safe and painless test that uses ultrasound (sound waves) to build a series of pictures of the heart.

How & When Is It Treated?

Our Nemours Cardiac Center experts may treat secundum-type atrial septal defects either by surgical repair or a catheter technique (when a tiny, hollow tube is inserted into an artery or vein). Surgical repair may involve either suture closure (reserved for small ASDs) or patch closure. The patch material may be a portion of the child’s own pericardium (the sac around the heart) or a synthetic material. The catheter technique involves closing the atrial septal defect (ASD) with a synthetic device that plugs the hole. The device is introduced through a heart catheter, which is passed through a vein in the leg that leads up to the heart. Initially, the device is held in place by the natural pressures created within the atria. Over time, the device acts as a framework over which normal tissue grows. Both sinus venosus and primum-type atrial septal defects require surgical closure with a patch.

We usually repair atrial septal defects before about age 5. When an atrial septal defect (ASD) is identified later in life, it’s usually repaired at that time.

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How Will It Affect My Child Long Term?

After repair (either surgical or with a catheter), the blood flows normally through the heart and a child shouldn’t have any long-term activity limitations.

If your child has an atrial septal defect (ASD), know that at the Nemours Cardiac Center we’re here to give your child the very best, most comprehensive and compassionate care. Our goal is to guide your family, from start to finish, through your child’s heart defect journey — and to help your child live the healthiest, most fulfilling life possible.

Learn More About Congenital Heart Defects »

Learn More About Atrial Septal Defect (ASD)

Get detailed information and visuals from Nemours’

Heart Murmurs

A heart murmur is an abnormal sound (like a blowing or whooshing) that’s usually detected by a doctor who’s listening to the heart with a stethoscope during a routine exam. Learn More »

Why Choose Us

From our outcomes to our family-centered care, find out all of the reasons why your child’s heart will be in good hands at the Nemours Cardiac Center. Learn More »

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After 5 p.m. and Weekends:

Cardiac Intensive Care Unit: (302) 651-6644
General Inpatient Unit, 2B: (302) 651-6690


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