Atrial septal defect (ASD)
Atrial septal defect (ASD) is a heart defect that is present at birth (congenital).
While the baby is in the womb, there is normally an opening between the upper chambers of the heart (atria) to allow blood to flow around the lungs. This opening usually closes around the time when the baby is born. If the opening does not close, the hole is called an atrial septal defect, or ASD.
Causes, incidence, and risk factors
If the opening does not close, the hole is called an ASD and blood continues to flow between the two heart chambers. This is called a shunt. Pressure in the lungs may build up. Over time, there will be less oxygen in the blood that goes to the body.
Small atrial septal defects often cause very few problems and may be discovered much later in life. Many problems can occur if the opening is large, or there is more than one opening.
ASD is not very common.
A person with no other heart defect, or a small defect (less than 5 millimeters) may not have symptoms, or the symptoms may not occur until middle age or later.
Symptoms that do occur may begin at any time after birth through childhood, and can include:
- Difficulty breathing (dyspnea)
- Frequent respiratory infections in children
- Sensation of feeling the heart beat (palpitations) in adults
- Shortness of breath with activity
Signs and tests
The doctor will check how large and severe an ASD is based on the symptoms, physical exam, and the results of heart tests.
The doctor may hear abnormal heart sounds when listening to the chest with a stethoscope. A murmur may be heard only in certain body positions, and sometimes a murmur may not be heard at all. A murmur means that blood is flowing in a turbulent (not smooth) way.
The physical exam may also reveal signs of heart failure in some adults.
An echocardiogram is a test that uses sound waves to create a moving picture of the heart. It is often the first test done.
Other tests that may be done include:
- Cardiac catheterization
- Coronary angiography (for patients over 35 years old)
- Doppler study of the heart
- Heart MRI
- Transesophageal echocardiography (TEE)
ASD may not need treatment if there are few or no symptoms, or if the defect is small. Surgery to close the defect is recommended if the defect causes a large amount of shunting, the heart is swollen, or symptoms occur.
A procedure has been developed to close the defect without surgery.
- The procedure involves placing an ASD closure device into the heart through tubes called catheters.
- The health care provider makes a tiny surgical cut in the groin, then inserts the catheters into a blood vessel and up into the heart.
- The closure device is then placed across the ASD and the defect is closed.
Not all patients with atrial septal defects can have this procedure.
Right after the surgery for ASD, patients should get antibiotics before dental procedures to reduce their risk of developing an infection in the heart. Antibiotics are not needed later on.
In infants, small ASDs (less than 5 mm) will often close on their own or cause no problems. Larger ASDs (8 to 10 mm) most often do not close and may need a procedure.
Important factors include the size of the defect, the amount of extra blood flowing through the opening, and whether the person has any symptoms.
Some patients with ASO may have other congenital heart conditions, such as a leaky valve or a hole in another area of the heart.
People with a larger or more complicated ASD are at an increased risk for developing a number of problems, including:
- Arrhythmias, particularly atrial fibrillation
- Heart failure
- Heart infections (endocarditis)
- High blood pressure in the arteries of the lungs (pulmonary hypertension )
Calling your health care provider
Call your health care provider if you have symptoms of an atrial septal defect.
There is no known way to prevent the defect, but some of the complications can be prevented with early detection.
Marelli AJ. Congenital heart disease. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 69.
Webb GD, Smallhorn JF, Therrien J, Redington AN. Congenital heart disease. In: Bonow RO, Mann DL, Zipes DP, Libby P, Braunwald E, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 9th ed. St. Louis, Mo: WB Saunders; 2011:chap 65.
Hanslik A, Pospisil U, Salzer-Muhar U, Greber-Platzer S, Male C. Predictors of spontaneous closure of isolated secundum atrial septal defect in children: a longitudinal study. Pediatrics. 2006;118(4):1560-1565.
Last reviewed 6/4/2012 by David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Michael A. Chen, MD, PhD, Assistant Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, Washington. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.
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