Atrial Septal Defect

An atrial septal defect is a congenital heart defect
where the wall between the right and left atria
does not close properly, leaving a hole between the two atria.

Atrial septal defect (ASD) is a congenital birth defect. It is an abnormality in the atria (the upper chambers of the heart). In ASD, the wall between the left and right chambers is not completely closed.

In a developing fetus, there is an opening between the left and right atrium. This opening allows the blood to bypass the lungs. When the baby is born, that opening is normally closed, and blood will flow to the lungs.

In babies born with ASD, blood passes from the left atrium to the right atrium. This eventually can cause problems in the lungs.

ASD occurs in about four out of every 100,000 babies. Those with minor-to-moderate defects may not suffer any complications or symptoms. Very small ASDs close on their own about 90% of the time. Those with more severe defects may have disabilities later in life.

Causes

ASD is a congenital defect. This means that it occurs during fetal development and is present at birth. Some cases may be caused by a genetic defect or abnormality inherited from a parent. Others can be caused by illnesses suffered by the mother during pregnancy.

Most of the time, the cause is unknown.

Risk Factors

Because the cause is largely unknown, there are no known risk factors for this condition.

Symptoms

Symptoms include:

• Fatigue and tiring easily during activity
• Sweating
• Rapid breathing, difficulty breathing, or shortness of breath
• Persistent respiratory infections
• Poor growth
• Heart palpitations
• Poor appetite
• Heart murmur

People with minor-to-moderate defects may show no symptoms. Or, they may not begin to show symptoms until later in life.

Diagnosis

Your doctor will ask about your symptoms and medical history. You will also be examined. Tests may include the following:

• Chest x-ray—a test that uses radiation to take a picture of structures inside the body, especially bones
• Echocardiogram—a test that uses high-frequency sound waves (ultrasound) to examine the size, shape, and motion of the heart
• Doppler image of the heart
• Cardiac catheterization—a tube-like instrument inserted into the heart through a vein or artery (usually in the arm or leg) to detect problems with the heart and its blood supply
• Coronary angiography (patients over age 35 only)—x-rays taken after a dye is injected into the arteries, allows the doctor to look for abnormalities in the arteries
• MRI of the chest—a test that uses magnetic waves to make pictures of structures inside the chest
• Electrocardiogram (ECG, EKG)—a test that records the heart’s activity by measuring electrical currents through the heart muscle

Treatment

ASD may not need treatment if there are few or no symptoms, or if the defect is small. Surgery to close the defect is recommended if the defect causes a large amount of shunting, 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.

Right after the surgery for ASD, patients should get antibiotics before dental procedures to reduce their risk of developing an infection in the heart. Antibiotics are not needed later on.

Outlook (Prognosis)

In infants, small ASDs (less than 5 mm) will often close on their own or cause no problems. Larger ASDs (8 to 10 mm) most often do not close and may need a procedure.

Important factors include the size of the defect, the amount of extra blood flowing through the opening, and whether the person has any symptoms.

Some patients with ASO may have other congenital heart conditions, such as a leaky valve or a hole in another area of the heart.

Possible Complications

People with a larger or more complicated ASD are at an increased risk for developing a number of problems, including:

• Arrhythmias, particularly atrial fibrillation
• Heart failure
• Heart infections (endocarditis)
• High blood pressure in the arteries of the lungs (pulmonary hypertension )
• Stroke

Prevention

Since the condition is a congenital defect with unknown causes, there are preventive measures. Early diagnosis and early treatment can help prevent complications