MedlinePlus Medical Encyclopedia: Atrial septal defect

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Atrial septal defect

Contents of this page:
Illustrations Alternative names Definition Causes, incidence, and risk factors Symptoms Signs and tests	Treatment Expectations (prognosis) Complications Calling your health care provider Prevention

Illustrations

Heart, section through the middle

Heart, front view

Atrial septal defect

Alternative names Return to top

ASD

Definition Return to top

Atrial septal defect is an abnormality of the upper chambers of the heart (atria) where the wall between the right and left atria does not close completely. This defect is present at birth (congenital).

Causes, incidence, and risk factors Return to top

Atrial septal defect (ASD) is a congenital heart defect. In fetal circulation there is normally an opening between the two atria (the upper chambers of the heart) to allow blood to bypass the lungs. This opening usually closes about the time the baby is born. If the ASD is persistent, blood continues to flow from the left to the right atria. This is called a shunt.

ASD is present in 4 out of 100,000 people. When the person has no other congenital defect, symptoms may be absent, particularly in children. Symptoms usually have manifested by age 30. Individuals with ASD are at an increased risk for developing a number of complications including:

infective endocarditis (a bacterial infection of the heart)
heart failure
an abnormally fast heart rhythm known as atrial fibrillation

Symptoms Return to top

frequent respiratory infections in children
difficulty breathing (dyspnea)
shortness of breath with activity
sensation of feeling the heart beat (palpitations)

Note: People with small-to moderate-sized defects may show no symptoms at all, or not until middle age or later.

Signs and tests Return to top

There may be a palpable pulsation of the pulmonary artery in the chest. Examination with a stethoscope (auscultation) of the heart usually reveals abnormal heart sounds. There may be a murmur caused by the increased blood flow across the pulmonic valve, and signs of heart failure. If the shunt is large, increased blood flow across the tricuspid valve (between the right atrium and ventricle) may be responsible for an additional murmur.

Tests that may be performed in the diagnosis of ASD include:

A chest X-ray
An echocardiography (ultrasound of the heart) or a contrast echocardiography
A color Doppler/ study of the heart
Transesophageal echocardiography (TEE)
A cardiac catheterization
A coronary angiography (for patients over 35 years old)
An MRI of chest (sometimes)

An ECG may show atrial fibrillation, right atrial enlargement, or a pattern of delayed electrical conduction in the heart.

Treatment Return to top

ASD may not require treatment if there are few or no symptoms, or if the defect is small. Surgical closure of the defect is recommended if the atrial septal defect is large or if symptoms occur.

Recently, a new procedure has been developed to close the defect without surgery. This involves the introduction of a closure device into the heart through wires or catheters.

A tiny incision is made in the groin to introduce the catheters. They are then advanced into the heart where the closure devise is placed across the ASD and the defect is closed.

This procedure is relatively new and may not be applicable to all patients. Prophylactic (preventive) antibiotics should be given prior to dental procedures to reduce the risk of developing infective endocarditis.

Expectations (prognosis) Return to top

With a small-to-moderate atrial septal defect, a person may live a normal life span without symptoms. Larger defects may cause disability by middle age because of increased blood flow and shunting of blood back into the pulmonary circulation.

Complications Return to top

Pulmonary hypertension
Arrhythmias, particularly atrial fibrillation
Heart failure
Infective endocarditis

Calling your health care provider Return to top

Call your health care provider if symptoms indicating an atrial septal defect develop.

Prevention Return to top

There is no known way to prevent the defect, but some of the complications can be prevented with early detection.

Update Date: 4/27/2004

Updated by: Fabian Arnaldo, M.D., Department of Cardiology, Henry Ford Hospital, Detroit, MI. Review provided by VeriMed Healthcare Network.

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