Ventricular Septal Defect
(VSD)
Medical Author: John Mersch, MD, FAAP
Medical Editor: William C. Shiel Jr., MD, FACP, FACR
What is a ventricular septal defect (VSD)?
A ventricular septal defect (VSD) is a heart malformation present at birth. Any condition that is present at birth can also be termed a "congenital" condition. A VSD, therefore, is a type of congenital heart disease (CHD). The heart with a VSD has a hole in the wall (the septum) between its two lower chambers (the ventricles).
How common is a VSD?
The most frequent types of congenital malformations affect the heart. It is estimated that approximately
eight in 1,000 newborns have CHD. A VSD is the most frequent of the various types of CHD (25%-30% of all CHD). Approximately one infant in 500 will be born with a VSD.
What is the normal design of the heart?
The heart is made up of four separate chambers. The upper right chamber (atrium) receives blood back from the body with much of the oxygen extracted by the body organs and tissues. The blood is then pumped through a one-way valve into the lower right chamber (ventricle) from which it is pumped to the lungs to be again enriched with oxygen. This highly oxygenated blood then returns to the upper left sided chamber (atrium) and next passes through a one way valve into the lower left chamber (ventricle). From there, the oxygenated blood is pumped out into a large blood vessel (the aorta) and is distributed throughout the body through arteries.
The two upper chambers (right and left atria) are separated by a wall of muscle called the septum. Similarly the two lower chambers (right and left ventricles) are also separated by a separate muscular septum. These septa (plural of septum) keep the lower oxygenated blood that has returned from the body from mixing with the highly oxygenated blood which has returned from the lungs.
A VSD is a hole in the ventricular septum.
How do VSDs cause problems?
The pressure generated during contraction by the left ventricle is higher than that generated by the simultaneous contraction of the right ventricle. Blood will thus be pushed through the VSD (also called "shunted") from the left ventricle to the right ventricle. The right ventricle has to do extra work to handle the additional blood volume. It may have trouble keeping up with the load and enlarge, affecting its ability to pump efficiently. In addition, the lungs receive too much blood under too much pressure. The arterioles (small arteries) in the lungs thicken in response to the excess blood under excess pressure. If this extra pressure persists, permanent damage can be done to the lungs.
It makes a considerable difference whether the size of the VSD is small or large.
Next: How is a VSD diagnosed? What are the symptoms of a VSD? »
- Chest X-ray - A chest x-ray is a radiology test that involves exposing the chest briefly to radiation to produce an image of the chest and the internal organs of the chest. chest x-ray can be used to define abnormalities of the lungs such as excessive fluid, pneumonia, bronchitis, asthma, cysts, and cancers.
- Birth Defects - Read about birth defects, the leading cause of infant mortality during the first year. Causes of birth defects include ingestion of drugs or alcohol during pregnancy, genetic, hereditary, or environmental factors.
- Electrocardiogram (ECG or EKG) - Read about the Electrocardiogram (ECG, EKG) procedure used to reflect underlying heart conditions such as agnina, occurance of a prior heart attack or of an evolving heart attack, and more.
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