Congenital heart defects (also called congenital heart diseases) are structural abnormalities that are present in the heart at birth.
What is an atrial septal defect?
An atrial septal defect (ASD) is a hole in the septum, or muscular wall, that separates the heart’s two upper chambers (atria). An ASD occurs when part of the atrial septum does not form properly.
Types of ASDs
Atrial Septal Defect
Within the broad category of ASDs, there are several types of defects. Atrial septal defects are classified by where they occur and their size.
A secundum ASD is a hole in the middle of the atrial septum, which lets blood flow from the left chamber to the right chamber, or from the right chamber to the left chamber, depending on pressures in the atria.
A patent foraman ovale (PFO) is a "flap" that is present when the atrial septum does not close properly at birth. A PFO allows blood to flow from the right atrium to the left atrium. This type of defect generally only permits blood flow when there is more pressure inside the chest, such as straining during a bowel movement, coughing or sneezing. Learn more about PFO.
More complicated and rare types of ASDs involve different parts of the septum and also involve abnormal blood return from the lungs (sinus venosus) or heart valve abnormalities (primum ASDs).
What causes ASDs?
About 10 percent of congenital heart problems are caused by specific genetic defects. Most congenital heart defects are likely due to maternal environmental factors combined with a genetic predisposition. Environmental factors include use of alcohol and street drugs, as well as diseases such as diabetes, lupus and rubella.
Who is affected by ASDs?
Atrial septal defects account for about seven percent of all congenital heart defects, making them the third most common type. In addition, ASDs are the most common congenital defect in adults and are more common among women than men.
What are the long-term effects of ASDs?
Normally, the right side of the heart pumps blood that is low in oxygen to the lungs, while the heart’s left side pumps oxygen-rich blood to the body. When there is an ASD, blood from the left and right sides mix, and the heart generally does not work at its most efficient level.
The risk of problems is greater when the defect is large (greater than 2 cm). Problems may include:
- Right heart enlargement (leading to right heart failure)
- Heart rhythm disturbances, including atrial fibrillation or atrial flutter, occur in 50 to 60 percent of all patients over age 40 with an ASD.
- Pulmonary hypertension (high blood pressure in the arteries that supply blood to the lungs). Blood normally flows from the left side of the heart to the right, but in patients with an ASD and severe pulmonary hypertension, the blood flow across the ASD can reverse (flow right to left). As a result, oxygen levels in the blood will decrease, leading to a condition known as Eisenmenger syndrome.
- Leaking tricuspid and mitral valves as a result of enlargement of the heart
What are the symptoms of ASDs?
Although ASDs are present from birth, there are usually no associated symptoms, and the condition can go undetected until adulthood. In some patients, the defect is discovered incidentally during a chest X-ray that reveals enlargement of the right side of the heart.
By age 50, an individual with an ASD may start having symptoms such as shortness of breath, fainting, irregular heart rhythms or fatigue after mild activity or exercise.
In people with PFO, a stroke may be the first indication of the defect. More than 40 percent of people who have a stroke but do not have any other risk factors for a stroke are diagnosed with PFO.
How is an ASD diagnosed?
An assessment for an ASD may include:
- Electrocardiogram (ECG/EKG): An electrocardiogram, a graph of the heart’s electrical activity (heartbeat)
- Chest X-ray to evaluate the size of the heart and the blood vessels that supply blood to the lungs
- Transthoracic echocardiography/Doppler examination: An ultrasound image of the heart combined with measurements of blood flow to assess the heart’s structure and function
- Transesophageal echocardiography (TEE)/Doppler examination: An ultrasound image obtained via the esophagus to provide a clearer image of the atria, more precisely define the defect’s size and shape and to evaluate the health of the heart valves. The use of TEE helps the physician easily distinguish a PFO from other types of ASDs.
- Intracardiac echocardiography (ICE)/Doppler examination: An ultrasound image obtained by inserting a tiny camera (echo probe) into the chambers of the heart via a peripheral vein. The test can define the size and shape of the defect and the direction of the blood flow across it. This study often is used during percutaneous (nonsurgical) repair of the defect.
- Right heart catheterization: A small, thin tube (catheter) is inserted into the heart via the peripheral vein. Pressures and the amount of oxygen in the blood (oxygen saturations) are measured in each chamber. The oxygen saturations determine how much blood is flowing across the ASD by measuring how much the oxygen level increases beyond the site of the ASD. The ASD also can be crossed using a catheter and sized with a balloon, or contrast dye can be injected into the left atrium to determine the size the defect (atrial angiogram).
- Left heart catheterization: During this procedure, angiography (injecting dye into the blood vessels of the heart through a catheter) can be performed to check for significant coronary artery disease.
How is an ASD treated?
Treatment of an ASD depends on the type and size of the defect, its effect on the heart, and the presence of any other related conditions, such as pulmonary hypertension, valve disease or coronary artery disease.
In general, when a patient has a large ASD that causes significant shunting (flow of blood through the defect) and right-sided heart enlargement, Cleveland Clinic specialists recommend correcting the defect.
The size of the defect correlates with the degree of shunting—the more shunting, the greater the risk of long-term complications such as atrial fibrillation and pulmonary hypertension. The degree of shunting is determined by echocardiography, MRI or oxygen saturations measured during catheterization. The degree of right-heart enlargement, as measured by echocardiography or MRI, usually correlates with the degree of shunting.
Nonsurgical, percutaneous (through the skin) repair is the preferred treatment for most secundum ASDs, but surgery may be needed to repair other types of ASDs (see Surgerical Repair section below for more information). Your doctor will determine what type of repair procedure is best for you.
Two different brands of closure devices are approved by the U.S. Food and Drug Administration for percutaneous ASD closure—Amplatzer® Septal Occluder and the GORE HELEX® Septal Occluder. The closure devices differ in design, but the placement method and their function are similar.
The device is attached to a catheter, which is inserted into a vein in the groin and advanced to the heart and through the defect, guided by X-ray and intracardiac echo. As the device slowly is pushed out of the catheter, it opens up to cover each edge of the defect, sealing it closed. Over time, tissue grows over the implant and it becomes part of the heart.
Before a percutaneous closure device procedure, the patient will have a cardiac catheterization to determine the size and location of the defect. Pressures inside the heart chambers also will be measured.
For at least the first six months after the repair, the patient will need to take an anticoagulant such as aspirin, clopidogrel or warfarin (Coumadin) to prevent clots from forming on the device.
Percutaneous Closure Devices for ASD Repair
AMPLATZER® Septal Occluder
The AMPLATZER® Septal Occluder is a transcatheter closure device used to treat ASDs. It consists of two Nitinol wire mesh discs filled with polyester fabric. It is folded into a special delivery catheter, similar to the catheter used to cross the heart defect during catheterization.
The catheter is inserted into a vein in the leg, advanced into the atrial septum and through the defect. When the catheter is in the proper position, the device slowly is pushed out of the catheter until the discs of the device sit on each side of the defect, like a sandwich. The two discs are linked together by a short connecting waist that matches the size of the defect. The discs and the waist are filed with polyester fabric to increase the device’s closing ability. Over time, heart tissue grows over the implant, and it becomes part of the heart, permanently correcting the defect.
GORE HELEX® Septal Occluder
The GORE HELEX® Septal Occluder is a transcatheter closure device used to treat ASDs. It is a disc-like device that consists of ePTFE patch material supported by a single Nitinol wire frame. The device is folded into a special catheter and inserted into a vein in the leg. Using a guide wire, the device is advanced through the atrial septum. When the catheter is in the correct position, the device slowly is pushed out of the catheter until it covers the defect. The device bridges the septal defect. Over time, heart tissue grows over the implant, and it becomes part of the heart, permanently correcting the defect.
Prior to the introduction of percutaneous techniques, surgical closure was the only treatment option for an ASD, regardless of the type of defect. Surgical repair may be needed for large secundum ASDs and other types of ASDs.
Surgical repair usually is performed using a tissue patch, preferably from the patient’s own pericardium (the membrane aorund the heart). Some secundum ASDs can be surgically closed with sutures alone.
The patient usually returns to the cardiologist 3, 6 and 12 months after a procedure for a follow-up physical exam and echocardiogram, and once a year thereafter. After a secundum ASD is repaired, most people can return to their regular activities without any activity restrictions (other than those associated with all heart catheterizations). Patients usually take a blood thinner for six months to a year after the repair to prevent blood clots and help the healing process. Patients who have had a stroke may need to take blood thinners indefinitely, and those with other heart problems, such as coronary artery disease or pulmonary hypertension, may need to take additional medication.
Patients who have heart surgery to repair a defect or receive a transcatheter closure device will need to take preventive antibiotics for at least six months after the repair procedure to reduce the risk of infective endocarditis. The doctor will provide specific guidelines about when to take antibiotics. According to the American Heart Association, there is not enough evidence to recommend taking preventive antibiotics for longer than six months.
Find a Doctor Who Treats Adult Congenital Heart Disease
Doctors vary in quality due to differences in training and experience; hospitals differ in the number of services available. The more complex your medical problem, the greater these differences in quality become and the more they matter.
Clearly, the doctor and hospital that you choose for complex, specialized medical care will have a direct impact on how well you do. To help you make this choice, read more about our Sydell and Arnold Miller Family Heart & Vascular Institute outcomes. See about us to learn more about the Miller Family Heart & Vascular Institute at Cleveland Clinic.
The Center for Adult Congenital Heart Disease in the Sydell and Arnold Miller Family Heart & Vascular Institute is a specialized center involving a multi-disciplinary group of specialists, including cardiologists, cardiac surgeons and nurses from Cardiovascular Medicine, Pediatric Cardiology, Pediatric and Congenital Heart Surgery, Cardiothoracic Surgery, Diagnostic Radiology, Pulmonary, Allergy and Critical Care Medicine, and Transplantation Center, who provide a comprehensive approach to diagnosing and treating adult congenital heart disease.
- Shunichi H, et al. Effect of medical treatment in stroke patients with patent foramen ovale. Circulation. 2002 ;105(22):2625-31.
- Taafee M, et al. Comparison of three patent foramen ovale closure devices in a randomized trial (Amplatzer versus CardioSEAL-STARFlex versus Helex Occluder). The American Journal of Cardiology. 1 May 2008. 101(9):1353-1358.
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