Atrial septal defect

Atrial septal defect (ASD) is a congenital heart defect in which the wall that separates the upper heart chambers (atria) does not close completely. Congenital means the defect is present at birth.

Causes, incidence, and risk factors

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 around 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. If too much blood moves to the right side of the heart, pressures in the lungs build up. The shunt can be reversed so that blood flows from right to left. Small atrial septal defects often cause very few problems and may be found much later in life. Many problems can occur if the shunt is large, however. In advanced and severe cases with large shunts the increased pressure on the right side of the heart would result in reversal of blood flow (now from right to left). This usually results in significant shortness of breath.

ASD is not very common. When the person has no other congenital defect, symptoms may be absent, particularly in children. Symptoms may begin any time after birth through childhood. Individuals with ASD are at an increased risk for developing a number of complications including:

• Atrial fibrillation (in adults)

• Heart failure

• Pulmonary overcirculation

• Pulmonary hypertension

• Stroke

Symptoms

Small to moderate sized defects may produce no symptoms, or not until middle age or later. Symptoms that may occur 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 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. The physical exam may also reveal signs of heart failure in some adults.

If the shunt is large, increased blood flow across the tricuspid valve may create an additional murmur when the heart relaxes between beats.

Tests that may done include:

• Cardiac catheterization

• Chest x-ray

• Coronary angiography (for patients over 35 years old)

• Doppler study of the heart

• ECG

• Echocardiography

• Heart MRI

• Transesophageal echocardiography (TEE)

Treatments and drugs

If your child has an atrial septal defect, your doctor may recommend monitoring it for a period of time to see if it closes on its own, while treating any symptoms with medications. Many atrial septal defects close on their own during childhood. For those that don't close, some small atrial septal defects don't cause any problems and may not require any intervention. But, many atrial septal defects eventually require surgery to be corrected.

If your child needs treatment, the timing of it depends on your child's condition and whether your child has any other congenital heart defects.

Medications
Medications won't repair the hole, but they may be used to reduce some of the signs and symptoms that can accompany an atrial septal defect. Drugs may also be used to reduce the risk of complications after surgery. Medications may include those to:

• Keep the heartbeat regular. Examples include beta blockers (Lopressor, Inderal) and digoxin (Lanoxin).
• Reduce the risk of blood clots. Anticoagulants, often called blood thinners, can help reduce the chances of developing a blood clot and having a stroke. Anticoagulants include warfarin (Coumadin) and anti-platelet agents, such as aspirin.

Surgery
Many doctors recommend repairing an atrial septal defect diagnosed during childhood to prevent complications as an adult. For adults and children, surgery involves plugging or patching the abnormal opening between the atria. Doctors can do this through two methods:

• Cardiac catheterization. A thin tube (catheter) is inserted into a blood vessel in the groin and guided to the heart. Through the catheter, a mesh patch or plug is put into place to close the hole. The heart tissue grows around the mesh, permanently sealing the hole.
• Open-heart surgery. This type of surgery is done under general anesthesia and requires the use of a heart-lung machine. Through an incision in the chest, surgeons use patches or stitches to close the hole.

Follow-up care depends on the type of defect and whether other defects are present. For simple atrial septal defects closed during childhood, only occasional follow-up care is needed. For adults, follow-up care may depend on any resulting complications.

Lifestyle and home remedies

If you find out you have a congenital heart defect, or you've had surgery to correct one, you may wonder about limitations on activities and other issues.

• Exercise. Having an atrial septal defect usually doesn't restrict you from activities or exercise. If you have complications, such as heart failure or pulmonary hypertension, you may not be able to do some activities or exercises. Your cardiologist can help you learn what is safe.
• Preventing infection. Some heart defects, and the repair of defects, create changes to the surface of the heart in which bacteria can become stuck and grow into an infection (infective endocarditis). Atrial septal defects generally aren't associated with infective endocarditis. But if you have other heart defects in addition to an atrial septal defect, or if you've recently had atrial septal defect repair, you may need to take antibiotics before certain dental or surgical procedures.

Prevention

By Mayo Clinic staff In most cases, atrial septal defects can't be prevented. If you have a family history of heart defects or other genetic disorders, consider talking with a genetic counselor to assess what the risk might be before getting pregnant

Posted in: Atrial septal defect,CVS