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Septal Defects

  • Cynthia M. Johnson, MA
Publication Type:


Septal Defects

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


Septal defects are problems with the structure of the inside of the heart at birth. The problems are on a wall that is between the two upper chambers of the heart called atria. There are also two lower chambers of the heart 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. The blood from the left side should not mix with blood from the right side.

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. The means that the heart and lungs have to work harder than they need to work. This can lead to heart failure.

There are three main types of septal defects:

  • Atrial septal defect (ASD)—a hole in the wall between the atria
  • Ventricular septal defect (VSD)—a hole in the wall between the ventricles
  • Atrioventricular septal defect (AVSD)—a mix of ASD, VSD, and problems with openings between chambers called valves
Ventricular Septal Defect.

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The cause is not always known.

Risk Factors

Things that may raise the risk of these problems are:

  • Family history of birth defects of the heart
  • Exposure to a viral infection, drugs, or alcohol during pregnancy
  • Taking certain medicines during pregnancy, such as those used to treat seizure disorder
  • Genetic disorders, such as Down syndrome


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 may be done to look at the heart and the structures around it.


The goal of treatment is to fix the defect. How this is done depends on the type and size of the defect. Choices are:

  • Watching small ASDs and VSDs to see if they close on their own
  • Medicines to ease symptoms of heart failure
  • Surgery to repair a defect that is causing problems and has not closed on its own


Septal defects cannot be prevented. The risk of them may be lowered with prenatal care.





  • Adan, A., Eleyan, L., et al. Ventricular septal defect: diagnosis and treatment in the neonates: a systematic review. Cardiology in the Young, 2021; 31 (5): 756-761.
  • Atrial septal defects. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/atrial-septal-defects.
  • Congenital heart defects. American Heart Association website. Available at: https://www.heart.org/en/health-topics/congenital-heart-defects.
  • Ventricular septal defect. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/ventricular-septal-defect.


  • Chelsea Skucek, MSN, BS, RNC-NIC
Last Updated:

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.