What is a ventricular septal defect (VSD)?
A ventricular septal defect (VSD) is an abnormal opening between the left and right lower heart chambers (ventricles). The opening is in the wall (septum) between the two ventricles. With each heart contraction, the higher blood pressure in the left ventricle allows blood to flow from the left ventricle to the right ventricle where it must be repumped through the lungs. Septal defects vary in size and in the symptoms they produce.

How does it occur?
A VSD is the most common heart defect present at birth. It often occurs as a single defect with no known cause, but is also found in children with multiple problems.

About one in three children with a heart abnormality discovered at birth has a VSD. VSDs account for one in five heart abnormalities found during childhood and for one in 10 found in adults.

A VSD may occur when a heart attack weakens the muscle of the septum. Blood pressure in the left ventricle breaks open the weakened septum, pushing blood into the right ventricle through the new opening. Rarely, trauma to the heart may cause a VSD.

What are the symptoms?
A small VSD usually causes no problems. A large VSD in small children can lead to severe heart failure, a condition in which the heart cannot do its proper job as a pump.

If the opening is small, it does not stress the heart. The only symptom is a heart murmur, a sound your doctor can hear through a stethoscope.

Even if the defect is large, symptoms often do not occur for several weeks after birth. Some babies with a large VSD do not grow normally and may become undernourished. Other symptoms include sweating, increased breathing rate, and frequent lung infections.

A VSD that results from a heart attack is very serious. The heart muscle, weakened by the heart attack, must now also repump blood through the lungs. Sudden congestive heart failure often results in death. Shortness of breath, fluid in the lungs and other body tissues, and low blood pressure are common symptoms.

How is it diagnosed?
Your doctor is usually able to hear the heart murmur of a VSD through a stethoscope. A chest x-ray may show that the heart is slightly larger than normal and that there is more blood flow through the lungs.

A test called an echocardiogram uses sound waves to make pictures of the heart. Doppler ultrasound, a special type of echocardiogram, outlines flowing blood, shows the location of the VSD, and can help your doctor determine the size of the VSD. The echocardiogram also indicates whether there is increased blood pressure in the lungs.

A test called cardiac catheterization may be used to confirm the diagnosis and to be sure there are no other heart problems.

How is it treated?
Small VSDs may close on their own during the first years of childhood. The smaller the defect, the more likely it is to close on its own. But no one can predict which defects will close and which will not. A small VSD usually does not cause any problems and seldom requires treatment. People with a small VSD may lead normal lives.

However, a small VSD may serve as a location for bacterial endocarditis, an infection of the heart tissue that lines the defect. Bacterial endocarditis is a serious problem that can be prevented by taking antibiotics before any medical or dental work (even teeth-cleaning) that might cause germs to enter the bloodstream. Be sure to tell the dentist if you have a VSD.

Medium and large ventricular septal defects may need to be fixed with surgery. The VSD is closed by sewing a patch of a special material (Dacron) over the defect. The surgery helps prevent problems later in life. These problems include heart failure and high blood pressure in the lung arteries. Children who have surgery to repair a VSD before they are 2 years old usually do well. Older children and young adults who have surgical repair may still have some problems with their heart function. These problems, which include abnormal heart rhythms and a slightly reduced pumping ability of the heart, are usually not serious and may be treated with medications. Some VSDs may be closed with a patch that is positioned through a catheter, without surgery.

In the rare case that an infant with a VSD is very ill and has several other defects, an operation may be done to relieve the severe symptoms and to prevent high blood pressure from developing in the lungs. In this procedure, called a pulmonary artery band, the pulmonary artery is narrowed to reduce the amount of blood flow into the lungs. This will allow the child to grow. When the child is older, doctors will remove the band and repair the VSD.

A heart attack can make the septal muscle so weak that it cannot hold the stitches that would patch the defect. This makes the surgery quite risky. If other kinds of treatment can control heart failure for about 2 weeks, the septum recovers enough to hold the stitches, and successful surgery is more likely. Without surgery, people who develop a VSD after a heart attack have a high risk of death.

What are the results of treatment for ventricular septal defect?

When surgical repair of a VSD is not an emergency, the operation carries very little risk. Most people with repaired VSDs live normal lives and have a normal ability to exercise. The results are not as good if the VSD is due to a heart attack.