Atrial Septal Defect

Definition

Definition of Atrial Septal Defect
Atrial septal defect (ASD) is a form of congenital heart defect that enables blood flow between the left and right atria via the interatrial septum. The interatrial septum is the tissue that divides the right and left atria. Without this septum, or if there is a defect in this septum, it is possible for blood to travel from the left side of the heart to the right side of the heart, or vice versa. This results in the mixing of arterial and venous blood, which may or may not be clinically significant.

Symptoms

Symptoms of Atrial Septal Defect
Many babies born with atrial septal defects don't have associated signs or symptoms. In adults, signs or symptoms usually begin by age 30, but in some cases signs and symptoms may not occur until decades later.

Atrial septal defect symptoms may include:

1. Heart murmur, a whooshing sound that can be heard through a stethoscope
2. Shortness of breath, especially when exercising
3. Fatigue
4. Swelling of legs, feet or abdomen
5. Heart palpitations or skipped beats
6. Frequent lung infections
7. Stroke
8. Bluish skin color

Causes

Causes of Atrial Septal Defect
An atrial septal defect allows freshly oxygenated blood to flow from the left upper chamber of the heart (left atrium) into the right upper chamber of the heart (right atrium). There, it mixes with deoxygenated blood and is pumped to the lungs, even though it's already refreshed with oxygen. If the atrial septal defect is large, this extra blood volume can overfill the lungs and overwork the heart. If not treated, the right side of the heart eventually enlarges and weakens. In some cases, the blood pressure in your lungs increases as well, leading to pulmonary hypertension.

Diagnosis

Diagnosis of Atrial Septal Defect
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.

Treatment

Treatment of Atrial Septal Defect
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 defect is large, 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.

Prophylactic (preventive) antibiotics should be given prior to dental procedures to reduce the risk of developing infective endocarditis immediately after surgery for the ASD, but they are not required later on.

Prognosis

Prognosis of Atrial Septal Defect
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.

Prevention

Prevention of Atrial Septal Defect
In most cases, atrial septal defects can't be prevented. If you're planning to become pregnant, schedule a preconception visit with your health care provider. This visit should include:

1. Getting tested for immunity to rubella: If you're not immune, you should be vaccinated.
2. Going over your current health conditions and medications. You'll need to carefully monitor certain health problems during pregnancy: Your doctor also may recommend adjusting or stopping certain medications before you become pregnant.
3. Reviewing your family medical history: If you have a family history of heart defects or other genetic disorders, consider talking with a genetic counselor to determine what the risk might be before getting pregnant.