Atrial septal defect

Causes and Risks:
Atrial septal defect (ASD) is a congenital heart defect. In fetal circulation there is normally an opening between the 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 persistant, there is continuation of the opening between the left and right atria.

ASD is present in 4 out of 100,000 people. Symptoms are usually absent if other defects are not present. If symptoms are present they usually manifest before age 30. Individuals with ASD are at an increased risk for developing bacterial endocarditis .

Prevention:
This is a congenital defect; it is present at birth. There is no known way to prevent the defect. However, some of the complications can be prevented.

Symptoms:

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

Signs and Tests:
Examination with a stethoscope ( auscultation ) of the heart usually reveals abnormal heart sounds . There may be symptoms of heart failure or backflow of blood from the left ventricle into the left atrium due to the failure of the valve to close completely (mitral regurgitation) in some cases.

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

An ECG may show atrial fibrillation , right bundle branch block, or right atrial enlargement.

Treatment:
ASD may not require treatment if there are few or no symptoms. Surgical closure of the defect is recommended if the atrial septal defect is large or if symptoms occur. Prophylactic (preventive) antibiotics should be given prior to dental procedures to reduce the risk of developing bacterial endocarditis .

Prognosis:
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 decreased blood flow and shunting of blood back into the peripheral circulation without the blood having been reoxygenated by the lungs.

Complications:



Call Your Healthcare Provider:
Call your health care provider if symptoms indicate an atrial septal defect may be present.


This is a cross-sectional view of the interior of the heart. The valves, chambers, and associated vessels are labeled.



This is an illustration of the exterior of the heart. The arteries are colored blue and represent blood that is flowing into the heart. The veins are red and indicate blood flow out from the heart. The chambers are also labeled.