An atrial septal defect (ASD) is a hole in the part of the septum that separates the atria. (The atria are the upper chambers of the heart.)
An ASD allows oxygen-rich blood to flow from the left atrium into the right atrium, instead of flowing into the left ventricle as it should. So, instead of going to the body, the oxygen-rich blood is pumped back to the lungs, where it has just been.
Figure A shows the structure and blood flow inside a normal heart. Figure B shows a heart with an atrial septal defect. The hole allows oxygen-rich blood from the left atrium to mix with oxygen-poor blood from the right atrium.
An ASD can be small, medium, or large. Small ASDs allow only a little blood to flow from one atrium to the other. Small ASDs don't affect how the heart works and don't need any special treatment. Many small ASDs close on their own as the heart grows during childhood.
Medium and large ASDs allow more blood to leak from one atrium to the other. They're less likely to close on their own.
Most children who have ASDs have no symptoms, even if they have large ASDs.
The three major types of ASDs are:
If an ASD isn't repaired, the extra blood flow to the right side of the heart and lungs may cause heart problems. Most of these problems don't occur until adulthood, often around age 30 or later.
Possible complications include:
These problems develop over many years and rarely occur in infants and children. They also are rare in adults because most ASDs close on their own or are repaired in early childhood.
A ventricular septal defect (VSD) is a hole in the part of the septum that separates the ventricles. (The ventricles are the lower chambers of the heart.)
A VSD allows oxygen-rich blood to flow from the left ventricle into the right ventricle, instead of flowing into the aorta as it should. So, instead of going to the body, the oxygen-rich blood is pumped back to the lungs, where it has just been.
Figure A shows the structure and blood flow inside a normal heart. Figure B shows two common locations for a ventricular septal defect. The defect allows oxygen-rich blood from the left ventricle to mix with oxygen-poor blood in the right ventricle.
An infant who is born with a VSD may have one or more holes in the wall that separates the two ventricles. The defect also may occur alone or with other congenital heart defects.
Doctors will classify a VSD based on the:
VSDs can be small, medium, or large. Small VSDs don't cause problems and may close on their own. Small VSDs sometimes are called restrictive VSDs because they allow only a small amount of blood to flow between the ventricles. Small VSDs don't cause any symptoms.
Medium VSDs are less likely to close on their own. They may cause symptoms in infants and children. Surgery may be needed to close medium VSDs.
Large VSDs allow a lot of blood to flow from the left ventricle to the right ventricle. They're sometimes called nonrestrictive VSDs. Large VSDs likely won't close completely on their own, but they may get smaller over time.
Large VSDs often cause symptoms in infants and children. Surgery usually is needed to close large VSDs.
VSDs are found in different parts of the septum.
Over time, if a VSD isn't repaired, it may cause heart problems. A medium or large VSD can cause:
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December 9, 2013
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