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What is an ASD?
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Atrial Septal Defect (ASD)

Normally, oxygen-poor blood returns to the right atrium from the body, travels to the right ventricle, and then is pumped into the lungs where it is filtered and receives oxygen. Oxygen-rich blood returns to the left atrium from the lungs, passes into the left ventricle, and then is pumped out to the body through the aorta.

The septum is a wall that separates the heart's left and right sides. Septal defects are sometimes called a "hole" in the heart. A defect between the heart's two upper chambers (the atria) is called an atrial septal defect (ASD).

What is an ASD?
How does an ASD affect the body?
What are the treatment options for an ASD?
Is surgical repair an option to close my ASD?
How are implants different from surgery?

What is an ASD?

An atrial septal defect is an opening in the atrial septum, or dividing wall between the two upper chambers of the heart known as the right and left atria. ASD is a congenital (present at birth) heart defect. As the fetus is growing, something occurs to affect heart development during the first eight weeks of pregnancy, resulting in an ASD.

When there is a large defect between the atria, a large amount of oxygen-rich (red) blood leaks from the heart's left side back to the right side. Then this blood is pumped back to the lungs, despite already having been refreshed with oxygen. This is inefficient, because already-oxygenated blood displaces blood that needs oxygen.

An atrial septal defect allows oxygen-rich blood to pass from the left atrium, through the opening in the septum, and then mix with oxygen-poor blood in the right atrium.

Atrial septal defects occur in 4 percent to 10 percent of all children born with congenital heart disease.

There are three major types of atrial septal defects:

• secundum atrial septal defect
  This is the most common atrial septal defect. It is caused when a part of the atrial septum fails to close completely while the heart is developing. This causes an opening to develop between the atria.
• primum atrial septal defect
  This defect is part of the AV canals, and is often found at a split in the leaflet of the valve.

• sinus venosus atrial septal defect
  This defect occurs at the superior vena cava and right atrium juncture. In this defect, one or more of the pulmonary veins enter the right atrium instead of correctly entering the left atrium.

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How does an ASD affect the body?

Atrial septal defects result in blood flowing from the left atrium to the right atrium, causing the right ventricle and lungs to work extra hard to handle the flow. Usually, children with ASD's lead normal, healthy lives. Over time, however, the right ventricle may get larger, and the pressure in the main arteries of the lungs can increase. It is also common for abnormal heart rhythms to occur as a long-term consequence of this defect. All of these conditions can lead to a decrease in exercise tolerance, and if left untreated, ASD is known to shorten average life expectancy. 

Occasionally, blood will flow from the right atrium to the left atrium, resulting in an increased risk of a stroke from the debris that is normally filtered out by the lungs.

An ASD can cause lung problems if not repaired. A small opening in the atrial septum allows a small amount of blood to pass through from the left atrium to the right atrium. A large opening allows more blood to pass through and mix with the normal blood flow in the right side of the heart. When blood passes through the ASD from the left atrium to the right atrium, a larger volume of blood than normal must be handled by the right side of the heart. Extra blood then passes through the pulmonary artery into the lungs, causing higher pressure than normal in the blood vessels in the lungs.

The larger the volume of blood that goes to the lungs, the higher the pressure.

The lungs are able to cope with this extra pressure for a while, depending on how high the pressure is. In time, however, the blood vessels in the lungs become diseased by the extra pressure.

Many people have no symptoms and seem healthy. However, if the ASD is large, permitting a large amount of blood to pass through to the right side of the heart, the right atrium, right ventricle, and lungs will become overworked, and symptoms may be noted. The following are the most common symptoms of atrial septal defect.  Symptoms may include: 

• fatigue
• sweating
• rapid breathing
• shortness of breath
• poor growth in children

The symptoms of an atrial septal defect may resemble other medical conditions or heart problems.

For these reasons, the current standard of care is to close atrial septal defects to reduce the shunt to a level which allows the right heart size and blood flow into the lungs to return to normal.  

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What are the treatment options for an ASD?

There are several options available depending upon the size of the defect and effect on the patients quality of life.

Some individuals may need to take medications to help the heart work better, since the right side is under strain from the extra blood passing through the ASD. Medications that may be prescribed include the following:  digoxin (a medication that helps strengthen the heart muscle, enabling it to pump more efficiently) and/or diuretics (the body's water balance can be affected when the heart is not working as well as it could). These medications help the kidneys remove excess fluid from the body.

One option for repair if medical therapy fails is the percutaneous placement of a septal repair implant.  This procedure is done in the cardiac cath lab.  The third option is having the defect closed with stitches or a special patch during an open heart procedure.

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Is surgical repair an option to close my ASD?

Surgical repair    

The defect may be closed with stitches or a special patch during an open heart procedure. Open heart surgery for ASD closure is a major, invasive procedure which generally follows this sequence:

1. The patient is anesthetized using a deep general anesthesia.
2. The breastbone is cut lengthwise about 5-8 inches.
3. The chest cavity is cut open and the heart exposed.
4. The heart is stopped and the patient is put on a heart-lung machine.
5. The heart is cut open and a cloth patch is sewn over the defect, or the defect edges are pulled and sewn together.
6. The heart is closed, and the patient's heart restarted. The heart lung machine is removed.
7. The chest cavity is sewn closed.
8. The breast bone is sutured together using wire sutures.
9. The patient is transferred to ICU and closely monitored, perhaps left on a breathing machine (respirator).
10. After 4-7 days in the hospital, the patient is discharged.
11. After 4-6 weeks, the patient returns to normal activity.

Open heart surgery is considered major surgery and carries with it some significant complications. Those include:

• Death
• Anesthesia Reaction
• Endocarditis
• Bleeding requiring transfusions
• Transfusion reactions
• Wound infection
• Myocarditis
• Stroke & TIA
• Arrhythmias requiring medications or pacemakers
• Pleural & pericardial effusions

While the surgical history in congenital disease is good, the frequency of complications increases with the severity of the heart disease. In addition, the surgery does not always result in total closure of the defect.

If you are considering surgery, ask your surgeon or cardiologist for specific information about the results of the surgery at your hospital. Generally, surgery requires 4 - 7 days in the hospital in uncomplicated cases, and 4-6 weeks of recovery at home prior to returning to full, normal activity. Pain can be significant, and pain management is routinely provided during the post operative and recovery phase.

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How are implants different from surgery?

Transcatheter Repair

One option for repair if medical therapy fails is the percutaneous placement of a septal defect repair implant which provides the following advantages over open heart surgery.

• Avoidance of being on a heart-lung machine.
• Avoidance of a highly invasive procedure.
• Avoidance of direct cutting and/or suturing of the heart.
• Avoidance of lengthy hospitalization and recovery, with the attendant pain and limitations that result.

Although not medically important, many parents and patients also indicate that the cosmetic benefit of avoiding a major scar on the chest is an important consideration, particularly in children and young adults.

As with all medical procedures, there are risks and potential complications associated with procedures used to deliver implants, and some of them are listed below. Perhaps most importantly, the risk of a patient having a recurrent stroke or TIA with an implant has not been proven in any comparative way to medical therapy.

• Patients may be allergic to the contrast dye used in the procedure.
• There is a risk of embolic stroke from clots, venous debris, or air getting into the heart.
• There may be bleeding or injury to the vein at the insertion site.
• There are risks associated with the use of transesophageal echo (used to help the doctor see the implant during the procedure).
• The device itself may dislodge, making surgery necessary if the doctor cannot retrieve it.
• The implant framework may fracture, or (worse) even erode into or through the walls of the heart if it is too stiff, or is unable to adjust to the wide variety of differences in the septal anatomy of people.
• The patient may develop Endocarditis.
• There is a risk that a clot may develop on the device itself.

All of these complications have been reported through the years from different types of septal implants.

See the FDA disclaimer page for more information

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