The heart is divided into four separate chambers. The upper chambers, or atria, are divided by a wall called the septum. An atrial septal defect (ASD) is a hole in that septum. Atrial septal defects are one of the most common heart defects seen. When an atrial septal defect is present, blood flows through the hole primarily from the left atrium to the right atrium. This shunting increases the blood volume in the right atrium which means more blood flows through the lungs than would normally.
If left untreated, atrial septal defect may cause problems in adulthood. These problems may include pulmonary hypertension (which is high blood pressure in the lungs), congestive heart failure (weakening of the heart muscle), atrial arrhythmias (which are abnormal rhythms or beating of the heart) and an increased risk of stroke.
In most children, atrial septal defects cause no symptoms. A very large defect may allow so much blood flow through it to cause congestive heart failure symptoms such as shortness of breath, easy fatigability, or poor growth. Most often an atrial septal defect is diagnosed when a physician hears a heart murmur during a physical examination. The murmur doesn't actually come from blood going across the hole, but rather from the pulmonary valve area because the heart is forcing an unusually large amount of blood through a normal sized valve.
The second heart sound is characteristically "split" which is different than what is heard when listening to a normal heart.
Hearing a murmur on a physical exam is the most common reason an atrial septal defect is suspected. Echocardiography is the primary method used to confirm the presence of an atrial septal defect.
Echocardiography can show not only the hole and its size, but also any enlargement of the right atrium and ventricle in response to the extra work they are doing.
An electrocardiogram (ECG) may show evidence of thickening of the heart muscle and a chest X-ray may show enlargement of the heart and increased blood flow to the lungs.
In some children an ASD may close on it''s own without treatment. With a small atrial septal defect, this may be as high as 80 percent in the first 18 months of life. An ASD still present by 3 years of age will probably never close on its own.
An atrial septal defect is most commonly closed by open-heart surgery. The surgeon may be able to directly close the hole with sutures or, depending on the size and shape of the hole, may need to close it with a patch.
Depending on the size and the area of the septum involved, many atrial septal defects may be closed by placement of a device called an Amplatzer Septal Occluder during a cardiac catheterization. This device, which was approved by the FDA in December 2001, is inserted through a catheter and covers the ASD by attaching to the atrial septum.
The benefits of being able to close an atrial septal defect with an Amplatzer device is that it can be put in place without stopping the patient''s heart or utilizing cardiopulmonary bypass, it doesn''t have the psychological trauma related to open-heart surgery and it doesn''t create a scarring across the chest the way open-heart surgery does.
Surgical closure of atrial septal defects is complication free in over 99 percent of cases. Although the Amplatzer device has only been utilized for several years, it''s success rate also appears to be very high. After ASD closure in childhood, the heart size returns to normal over a period of four to six months.
Following closure of an atrial septal defect, there should be no problems with physical activity and no restrictions. Regular follow-up appointments will be made with a cardiologist.