Alternate Names: ASD

Causes and Risks:

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 no other congenital defect coexists, symptoms may be absent, particularly in children. Symptoms usually have manifested by age 30. Individuals with ASD are at an increased risk for developing infective 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:

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

Signs and Tests:

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 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 similar to right bundle branch block (but with normal QRS duration).

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 infective 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 pulmonary circulation.

Complications:

• Pulmonary hypertension
• Arrhythmias, particularly atrial fibrillation
• Heart failure
• Infective endocarditis

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