(Atrioventricular Canal Defect; Atrioventricular Septal Defect; Endocardial Cushion Defect; Ventricular Septal Defect)
by Cynthia M. Johnson, MA
Septal defects are problems with the structure of the heart. They are present at birth. Septal defects are on the inside of the heart. They are on a wall that is between the chambers of the heart. There are two upper chambers of the heart called atria. There are 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. As a result, both the heart and lungs have to work harder than they need to work.
There are three main types of septal defects:
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.
In most cases the cause is not known.
Risk Factors TOP
Factors that may increase the risk of septal defects include:
Many people with ASD or VSD do not have symptoms. Large defects and AVSD may cause:
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 the structures around it.
Treatment may depend on the type and size of defect. There may be some treatment needed for any problems of the septal defect. This may mean:
Living With Septal Defects
Certain septal defects or surgeries may raise the risk of infections in the heart. You may need to take antibiotics before certain medical and dental procedures to lower 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 steps:
American Heart Association
National Institute of Child Health and Human Development
Canadian Cardiovascular Society
The College of Family Physicians of Canada
Antibiotic prophylaxis for heart patients. Mouth Healthy—American Dental Association website. Available at: https://www.mouthhealthy.org/en/az-topics/a/premedication-or-antibiotics?utm_medium=VanityUrl. Accessed July 23, 2018.
Atrial septal defects and patent foramen ovale. EBSCO DynaMed Plus website. Available at: http://www.dynamed.... Updated December 27, 2017. Accessed July 23, 2018.
Congenital heart defects. American Heart Association website. Available at:
...(Click grey area to select URL)
Accessed July 23, 2018.
Congenital ventricular septal defect (VSD) in children and adults. EBSCO DynaMed Plus website. Available at: http://www.dynamed.... Updated June 16, 2017. Accessed July 23, 2018.
6/18/2010 DynaMed Plus Systematic Literature Surveillance http://www.dynamed...: Jentink J, Loane M, Dolk H, et al. Valproic acid monotherapy in pregnancy and major congenital malformations. N Engl J Med. 2010;362(23):2185.
Last reviewed June 2018 by EBSCO Medical Review Board Kathleen A. Barry, MD
Last Updated: 7/24/2018
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