Atrial Septal Defect_KH_Kids

Atrial Septal Defect


What Is an Atrial Septal Defect?

Atrial septal defect (say: ay-tree-ul sep-tul dee-fekt), or ASD for short, is a heart condition that can affect kids. To understand an ASD, it helps to know how the heart works. The heart has four chambers. The lower chambers of the heart are called the ventricles. There are two ventricles: a left ventricle and a right ventricle. The upper chambers are the atria and there are two of them — a left atrium and a right atrium. (Atrium is an old word that meant the main room in an ancient Roman house, so the atria are "rooms" in your heart!)



Between the right and left atria, there is a wall called the septum that normally separates the blue and red blood. In a person with an atrial septal defect, there's an opening in that wall. This hole in the wall lets oxygen-rich blood from the left atrium mix with oxygen-poor blood on the other side. The extra blood that ends up crossing through the hole and flowing through the heart and out to the lungs creates a swishing sound, which is called a heart murmur. That sound may be the only clue that a kid may have an ASD.

Many kids with an ASD don't have any problems or symptoms because of it. Occasionally, a kid with a very large ASD may have a poor appetite, may tire easily, may grow slowly, may experience shortness of breath, or have lung problems, like pneumonia.

ASD Is One of the More Common Heart Defects

About 1 in every 100 babies is born with some type of heart defect. Atrial septal defects are one of the more common types of these heart defects. A person could be diagnosed with an ASD in infancy, childhood, during their teen years, or even as an adult.

In some kids with small-sized atrial septal defects (small-size holes), the hole can close up on its own. Most kids with a medium-sized or large-sized ASD will need some kind of procedure (such as surgery) to close the hole. If the hole is left open, later in life that person may develop other kinds of heart problems, such as an abnormal heartbeat. The person also could develop serious damage to the lung blood vessels. The risk of having a stroke, a problem where a clot or air bubble clogs up a blood vessel in the brain, is also increased in someone with ASD. To prevent these problems, doctors often recommend closing the hole while the kid is still young.

What Causes an Atrial Septal Defect?


In some cases, the tendency to develop an ASD may be inherited, or genetic. In other cases, an ASD may happen if the pregnant woman was exposed to chemicals or drugs while the baby was growing in her uterus. For most kids with ASDs, no one knows why they developed this problem.

What Do Doctors Do?

Kids who have ASDs may first find out that they have a heart murmur in the doctor's office. The next stop is usually to a pediatric cardiologist (say: pee-dee-ah-trik car-dee-ah-lo-jist), a doctor who specializes in diagnosing and treating heart disease in kids and teens.


  • chest X-ray, which produces a picture of the heart and surrounding organs
  • echocardiogram (echo), which uses sound waves to create a picture of the heart


What If The Hole Doesn't Close on Its Own?

If the hole needs to be closed, the doctor will decide whether the kid needs surgery or a cardiac catheterization (say: kar-dee-ak ka-thuh-tur-uh-zay-shun). With either one, the kid will get special medicine called anesthesia that causes sleepiness and prevents pain during the operation.




Reviewed by: Gina Baffa, MD
Date reviewed: November 2007
Originally reviewed: Terrence U. H. Chun, MD

Related Sites

National Heart, Lung, and Blood Institute (NHLBI)
American Heart Association

Related Articles

Heart Murmurs
Heart Disease