An atrial septal defect (ASD) is a hole in the wall (the septum) between the heart’s two uppermost chambers, the right atrium and the left atrium. This hole allows blood to flow in either direction between the left and right atrium. This hole is congenital (present from birth).
An ASD may cause several problems. First, it creates a condition in which the right chambers of the heart have to circulate extra blood, causing strain on both the heart and the vessels to the lungs. Over time, this condition leads to high blood pressure in these vessels. In addition, the strain put on the right-sided pumping chamber can lead to a weakening or enlargement of the right side of the heart and, if left untreated, eventually heart failure. This enlargement may also cause arrhythmias (irregular heart rhythms) to develop. Also, an ASD can allow blood clots from the body to enter the brain and cause a stroke.
Most patients do not have any symptoms in childhood. However, symptoms that might develop over time, depending on the severity of the ASD and other factors, include:
- shortness of breath, fatigue, and labored breathing while exercising
- irregular heart beats
- transient ischemic attacks (TIA), which result in stroke-like symptoms
- pulmonary hypertension (high blood pressure in the arteries of the lung; can lead to heart failure if not treated)
- reduction in lifespan of about 20 years on average if the ASD is not closed
An ASD is congenital, meaning it is a defect that is inborn or exists at birth. Stated another way, the defect is an abnormality, not a disease. The septum between the two atria of the heart did not develop normally before birth. What is known is that about 20 percent of ASDs that occur in infants close on their own in the first years of life.
How is an ASD diagnosed?
During a routine examination, your doctor may hear a murmur when listening to your heart. A heart murmur is an additional swishing sound heard in the heart. If a murmur is identified, your doctor will order other tests that can include the following:
- electrocardiogram (ECG or EKG) - a test that records the electrical changes that occur during a heartbeat; reveals abnormal heart rhythms (arrhythmias) and detects heart muscle stress
- chest X-ray - a test to show the size and shape of the heart and lungs
- echocardiogram - a test that uses sound waves to create a moving picture of the heart’s internal structures
- cardiac magnetic resonance imaging (MRI) - a test that uses three-dimensional imaging to reveal how blood flows through the heart and how the heart is working
- cardiac catheterization - a procedure that involves inserting a thin tube (a catheter) into a vein or artery and passing it into the heart to sample the level of oxygen, measure pressure changes, and make x-ray movies of the heart and its internal structures
Additional tests may be ordered as necessary.
How is an ASD treated?
If you or your child is diagnosed with an ASD, your primary care doctor will recommend that you meet with a congenital heart specialist (a doctor who has the training and equipment to determine the heart problem), who will order the necessary special tests, medical care, heart surgery, and follow-up checkups. The best treatment approach will depend on the patient’s symptoms as well as the size of the ASD. The ASD may need to be closed surgically through open-heart surgery or may be repaired through an outpatient catheter-based procedure
The children who have ASD are typically treated by pediatric cardiologists. In some cases it may go undetected until patients become adults. However, we offer non-surgical or percutaneous treatment of ASD in most adults. More frequently, percutaneous rather than surgical closure is preferred. As part of the procedure, you will undergo a small puncture in your groin and the closure device can then be placed in the hole. During this test, catheters (hollow, flexible, tube) will be inserted into the veins in your groins and advanced to your heart. A balloon may be placed across the opening to determine the size and location of the hole in your heart. Measurements are taken of the pressure inside your heart chambers. A tiny catheter with an echo transducer is placed in the heart and then the cardiologist will position the device to close the hole.
The AMPLATZER ® ASD septal occluder device consists of two wire mesh discs filled with polyester fabric. It is folded into a special catheter, similar to the catheter used during your catheterization. The special catheter is inserted into a vein in the leg and advanced into the heart and through the hole. When the device is in proper position, the device is slowly pushed out the catheter until the discs of the device sit on each side of the hole (like a sandwich). Over time, heart tissue grows over the implant, becoming part of the heart.
In few patients who would not be a candidate for non surgical closure due to their anatomy, they would be referred for surgery.