Small Ventricular Septal Defect


A small ventricular septal defect is a congenital heart defect, or a birth defect of the heart. Congenital heart defects are the most common form of birth defects, occurring in approximately 1 in 150 children. A ventricular septal defect (VSD) is the most common congenital heart defect; the overall incidence is 3-4 per 1000 children. There are many different types of VSD’s. The most common type, termed a muscular VSD, is formed when the muscle of the wall fails to completely seal. The majority of muscular VSD’s are very small and rarely of any physiologic consequence. Less common types of VSD’s include membranous, inlet and outlet types. These types are often larger and may impose a hemodynamic burden.

Physiologically, a VSD allows for oxygenated blood (“red blood”) to pass from the left ventricle to the right ventricle, join with deoxygenated blood (“blue blood”), and return to the lungs. The net effect of a VSD is therefore an increase in the total amount of blood that flows to the lungs. With a small VSD, the increase in blood flow to the lungs is generally negligible.


The cause of most small ventricular septal defects is unknown. The vast majority are not related to any genetic disorders or other syndromes. Most appear to be due to a failure of the heart muscle wall to completely seal or close during development in the womb.

Signs and Symptoms

Symptoms from a small ventricular septal defect are very rare. Larger VSD's can cause symptoms related to excess blood flow to the lungs. Fortunately this is rarely if ever the case with a small VSD. Likewise, symptoms such as chest pain, palpitations, or syncope are unusual in the setting of a small VSD.


Diagnosis of a small ventricular septal defect can be made in a number of different ways. On occasion a small ventricular septal defect may be identified before birth by the use of a fetal echocardiogram. After birth, a baby or child with a small VSD usually comes to attention due to the presence of a heart murmur. This simply refers to the sound that blood is making as it flows through the hole from one chamber to another. There are many other different causes of heart murmurs, including normal causes. An echocardiogram uses sound waves to visualize the intracardiac structures and is the easiest way to diagnose the size and location of a small VSD.


The vast majority of infants and children with small VSD's don’t require any treatment whatsoever. Between 50 to 75% of small ventricular septal defects detected in the first few months of life close spontaneously. Even in cases where a small VSD remains open, specific therapy is rarely if ever needed. The vast majority of children with small VSD's lead completely normal lives with no restrictions whatsoever.  They are free to participate in all activities, including competitive athletics, without any special restrictions.

Up until recently, children with any form of heart defect, including VSD’s, were recommended to use antibiotics prior to dental work or surgery to minimize the risk of heart-related infection (SBE prophylaxis).  However, in May 2007 the American Heart Association changed this recommendation such that now most children with congenital heart disease, including those with VSD’s, no longer require this precaution.

in summary, although a small ventricular septal defect can cause alarm and concern in parents, fortunately it rarely if ever causes problems in babies or children.

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