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 2 upper chambers of the heart called atria. 2 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 right 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 left 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 work.

There are 3 main types of septal defects:

  • Atrial septal defect (ASD)—a hole in the wall between the 2 upper chambers (atrium) of the heart
  • Ventricular septal defect (VSD)—a hole in the wall between the 2 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 3 of these defects except where noted.

Ventricular Septal Defect
Nucleus factsheet image
Copyright © Nucleus Medical Media, Inc.


In most cases the cause is not known.

Risk Factors

Factors that may increase the risk of septal defects include:

  • Family history of congenital heart defects
  • Exposure to a viral infection, drugs, or alcohol during pregnancy
  • Certain medications, such as those used to treat seizure disorder


Many people with ASD or VSD do not have symptoms. Large defects and AVSD may cause:

  • Shortness of breath
  • Getting tired easily
  • Poor growth


A septal defect may be found during a regular exam. The doctor may hear a heart murmur.

The heart may be tested. This can be done with:

Chest x-rays can evaluate the heart and surrounding structures.


Treatment may depend on the type and size of defect. There may be some treatment for any complications. Treatment options may include:

  • No treatment.
    • About 40% of all ASDs and 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, but small ASDs may increase in size over time.
  • Medication
    • May be needed for infants with septal defects with:
    • May include medications to help the heart beat strongly, keep the heart rate regular, decrease the amount of fluid in the blood, or increase blood flow to the lungs.
  • Surgery
    • May be recommended in children with:
      • Significant heart failure
      • Pulmonary Hypertension
      • Other significant symptoms related to the septal defect
      • ASDs past 2 years of age.
        • 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.
      • VSDs that do not close after 1 year.
      • AVSD
    • The hole may be closed with stitches or a patch
    • Infants with AVSD will also need repair of abnormal heart valves
    • Usually done as open-heart procedure
  • Some ASDs can be closed without surgery.
    • A device is placed in the hole with cardiac catheterization.
    • This is a process that sends the device to the heart through a large blood vessel.
  • Limiting physical activity may be needed for severe congestive heart failure

Living With Septal Defects

Certain septal defects or surgical procedures 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.


Follow these prevention guidelines:

  • Talk to your doctor before considering pregnancy.
  • Go to all prenatal screening tests.
  • Avoid alcohol and drugs during pregnancy.
  • Talk to your doctor about ways to reduce your risk of having a child with Down syndrome. One type of AVSD is associated with the syndrome.

Revision Information