When there is a large opening between the ventricles, a large amount of oxygen-rich (red) blood from the heart's left side is forced through the defect into the right side. Then it's pumped back to the lungs, even though it's already been refreshed with oxygen. This is inefficient, because already-oxygenated blood displaces blood that needs oxygen. This means the heart, which must pump more blood, may enlarge from the added work. High blood pressure may occur in the lungs' blood vessels because more blood is there. Over time, this increased pulmonary hypertension may permanently damage the blood vessel walls.

If the opening between the ventricles is small, it doesn't strain the heart. In that case, the only abnormal finding is a loud murmur.

Surgical Therapy
Closing small ventricular septal defects may not be needed. They often close on their own in childhood or adolescence. But if the opening is large, even in patients with few symptoms, closing the hole in the first two years of life is recommended to prevent serious problems later. Usually the defect is closed with a patch. Over time the normal heart lining tissue covers the patch, so it becomes a permanent part of the heart. Some defects can be sewn closed without a patch. Repairing a VSD restores the blood circulation to normal. The long-term outlook is good.

Ongoing Care

Medical
After their VSD is closed, patients should be examined regularly by a cardiologist. He or she will make sure that the heart is working normally.

Activity Restrictions
Most patients won't need to limit their activity. However, if you have pulmonary hypertension or your heart doesn't pump as well as it used to, you may need to limit your activity to how much you can endure. Your cardiologist will help determine if you need to limit your activity.

Endocarditis Prevention
Unclosed VSDs require endocarditis prophylaxis. After the VSD is successfully closed, preventive treatment is needed only during a six-month healing period. (See section on Endocarditis.)

Problems You May Have
Most people whose uncomplicated ventricular septal defects are repaired early in life don't have any significant long-term problems. In some people, the heart muscle may be less able to contract. This requires diuretics, agents to help the heart pump better and drugs to control blood pressure. Also, if pulmonary hypertension develops (it's uncommon), you may need more medical therapy.

Will You Need More Surgery?
People whose ventricular septal defects are repaired rarely need more surgery unless residual defects are seen afterwards. If this occurs, whether you'll need surgery depends upon the size of the residual defects