Atrial Septal Defect

Atrial septal defect (ASD) is an abnormal hole in the wall between the two upper chambers of the heart, called the right and left atria. When this hole occurs, too much blood flows from the left atrium to the right atrium and through the right side of the heart. This excess blood flows through the right ventricle, pulmonary artery and into the lungs making the heart work harder. The extra blood flowing to the lungs creates a noise called a murmur.

Small holes may close on their own by the time a child is 2 years old. In some people, the defect doesn't cause symptoms until middle age.

A large ASD causes several problems. The heart works harder because it pumps extra blood to the lungs, which may cause the right side of your heart to enlarge resulting in irregular heartbeats called arrhythmias. It also may cause congestive heart failure, usually in middle age. In addition, a large amount of extra blood flow damages the blood vessels in the lung. All ASDs larger than a few millimeters in diameter should be closed to prevent these problems.

Most atrial septal defects (ASD) are discovered during childhood when a murmur, an extra heart sound, is heard during a physical examination.

To help diagnosis ASD in adulthood, your doctor also may suggest the following tests:

  • Electrocardiogram (EKG or ECG), which records the heart's electrical activity
  • Chest X-ray to see the heart's size
  • Echocardiogram, which is an ultrasound examination of the heart

In addition, your doctor may use a cardiac catheterization procedure to inject a dye into the heart and to see on a moving picture X-ray how the heart and aorta are functioning.

Coronary angiography may be recommended for patients over age 40 to detect coronary artery disease.

In the past, atrial septal defect (ASD) closure required open-heart surgery through an incision in the chest using a heart-lung bypass machine. This procedure would require three to five days in the hospital for recovery. It is now possible to close ASDs without surgery.

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Reviewed by health care specialists at UCSF Medical Center.

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