Ventricular septal defect (VSD) is a hole in the wall (called the septum) that separates the right and left ventricles.
When the left ventricle contracts, in addition to sending blood out the aorta, it sends oxygenated blood through the defect to the right ventricle. In the right ventricle, this oxygenated blood mixes with the normal unoxygenated blood coming back from the body and then it is all pumped to the lungs. The result is more blood than normal is pumped to the lungs and, in turn, more blood than normal returns from the lungs to the left atrium and left ventricle. If the hole is more than small, then this increase in blood returning to the left atrium and left ventricle causes these chambers to enlarge and work harder than normal. If the enlargement is significant, then the left ventricle may not function efficiently and blood can back up into the lungs. This may lead to signs of congestive heart failure. In addition, large ventricular septal defects can lead to increased blood pressure in the arteries in the lungs (called pulmonary hypertension) and may eventually lead to damage in the small arteries in the lungs.
What are the warning signs and symptoms of ventricular septal defect?
There are often no obvious signs or symptoms of a ventricular septal defect in a newborn infant. After several days or weeks, the following may appear and suggest the presence of a VSD:
- Abnormal heart murmur
- Labored breathing
- Poor feeding
- Poor growth
How is ventricular septal defect detected?
Often the first sign of a ventricular septal defect is the presence of an abnormal heart murmur. This often leads to the performance of an echocardiogram, which generally will show the precise anatomy of the defect as well as its size and effect on the heart function.
What are the treatment options for ventricular septal defect?
Ventricular septal defects are small and most of these will get even smaller or close by themselves. A medium-sized ventricular septal defect may need to be closed surgically but it is often possible to wait several years to see if the VSD will get smaller on its own. Small VSDs often never need treatment. If the VSD, however, is large enough to cause the left ventricle to be enlarged and there are no signs that the hole is getting any smaller, surgery is generally recommended. Large ventricular septal defects will require surgical closure, the timing of which depends on the degree of symptoms. Symptoms often can be improved by giving the infant medication such as:
- Diuretics, which decrease the amount of fluid retention in the body by increasing urine output
- Digoxin, which helps the heart pump more efficiently
- After-load reducing medicines, which improve the forward flow of blood from the left ventricle to the aorta
If, in spite of medication, the infant is still symptomatic, then surgery will be necessary. If the symptoms are improved but the hole is large, then a short period of observation is possible to see if there are any signs that the hole is getting smaller. Recently, some ventricular septal defects have been closed in the cardiac catheterization laboratory with devices that are undergoing research. The vast majority still require surgical closure, however.