Cardiac & VascularCardiac and VascularDiseases and Conditions

Atrial Septal Defect

(Atrial Septal Defect; Atrioventricular Canal Defect; Atrioventricular Septal Defect; Endocardial Cushion Defect; Ventricular Septal Defect)


Septal defects are problems with the structure of the heart. They are present at birth. Septal defects are located on the inside of the heart. They are on a wall that separates the chambers of the heart. There are two upper chambers of the heart called atrium. Two lower chambers of the heart are called ventricles.

In a healthy heart, the blood flows from the body to the right atrium. The blood then goes into the right ventricle. The ventricle pumps this blood to the lungs to pick up fresh oxygen. The blood then returns to the left side of the heart. It enters the left atrium first, then down to the left ventricle. The ventricle pushes the blood out to the rest of the body.

Septal defects allow the blood to move between the left and right chambers. The blood most often moves from the left side of the heart into the right side. This means that blood that has just returned from the lungs may end up being sent right back to the lungs. As a result, both the heart and lungs have to work harder than they need to.

There are three main types of septal defects:
  • Atrial septal defect (ASD) — a hole in the wall between the two upper chambers (atrium) of the heart
  • Ventricular septal defect (VSD) — a hole in the wall between the two lower chambers (ventricles) of the heart
  • Atrioventricular septal defect (AVSD) — a combination of ASD, VSD, and problems with opening between chambers (called valves)
The stress of pushing extra blood to the lungs may lead to heart failure. The following information applies to all three of these defects except where noted.
Ventricular Septal Defect
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  • Causes

    In most cases the cause is not known. However, in a small number of cases, a defect may be caused by:
    • Family history of congenital heart defects
    • Exposure to a viral infection, drugs, or alcohol during pregnancy
  • Risk Factors

    For most, there are no known factors that increase your baby's chance of septal defects. Some medications during pregnancy have been linked to an increased risk of septal defects. These medicines include valproic acid for seizure disorder.
  • Symptoms

    Many people with ASD or VSD do not have symptoms. Large defects and AVSD may cause:
    • Shortness of breath
    • Getting tired easily
    • Poor growth
    • High blood pressure in the lungs and possibly damage to the blood vessels in the lungs (in VSD and AVSD)
  • Diagnosis

    An ASD may be found during a regular exam. The doctor may hear a heart murmur. This is a sound caused by an abnormal blood flow through a valve in the heart. In this case it is the extra large amount of blood moving through the right side of the heart. If your child's doctor suspects a heart defect, an echocardiogram may be done. An echocardiogram uses sound waves to create images of the heart. It can be used to show the size and shape of the hole in the heart. Other tests may include:
    • Electrocardiogram (ECG, EKG) — a test that records the electrical activity of the heart
    • Chest X-ray — a test that uses radiation to take a picture of structures inside the chest
  • Treatment

    Treatment may depend on the type and size of defect. There may be some treatment steps for any complications. Treatment options may include:
    • ASD treatment options include:
      • About 40 percent of all ASDs will close on their own during the first year of life. This is more likely to occur with small defects.
      • An ASD that still exists at age 2 is unlikely to ever close on its own. If it is not closed in childhood, it may cause problems in adulthood.
      • Surgery may be recommended in children with ASD's past age 2 years.
      • Some ASDs can be closed without surgery. A device is placed in the hole with cardiac catheterization. This is a process that send the device to the heart through a large blood vessel.
    • VSD treatment options include:
      • Many VSDs will close on their own during the first year of life. This is more likely to occur with small defects.
      • Small VSDs that do not close rarely cause problems.
      • Medium and large VSDs may cause problems. They may need supportive treatment in the first few months of life.
      • Surgery may be needed in children with defects that cause symptoms or do not close after 1 year.
    • AVSD treatment options include:
      • Most infants with AVSD will have symptoms. Therefore they will need treatment.
      • Medication may be needed. They can help the heart beat strongly, keep the heart rate regular, or decrease the amount of fluid in the blood flow.
      • Physical activity may need to be limited.
      • Surgery to close the defect.
    • congestive heart failure — infants with signs of congestive heart failure may need to take medicine.
    The type of surgery used most often for septal defects is open-heart surgery. The hole is closed with stitches or a patch. In AVSD, the abnormal valves are also repaired.

    Living With Septal Defects

    Certain septal defects may increase the risk of infections in the heart. You may need to take antibiotics before certain medical and dental procedures to decrease the risk of this infection. Check with your doctor to see if you need to do this. If you do need to take antibiotics, ask your doctor to explain when they may be needed.

  • Prevention

    There are no general guidelines for preventing septal defects. One type of AVSD is strongly associated with Down syndrome. Programs have been developed to help some parents reduce their risk of having a baby with this condition. Certain maternal health conditions or medications may affect the baby's health. Talk to your doctor before considering pregnancy.

    American Heart Association

    March of Dimes


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