Ventricular septal defect describes one or more holes in the muscular wall that separates the right and left ventricles of the heart -- the most common congenital (present from birth) heart defect.

Before a baby is born, the right and left ventricles of its heart are not separate. As the fetus grows, a muscular wall forms to separate these lower heart chambers. If the wall does not completely form, a hole remains. This is what is known as a ventricular septal defect, or a VSD.

It is estimated that up to 1% of babies are born with this condition. In the vast majority (80-90%) of babies born with this condition, the hole is small. They will have no symptoms, and the hole will close spontaneously as the muscular wall continues to grow after birth.

If the hole is large, then too much blood will be pumped to the lungs, leading to congestive heart failure. These babies are often have symptoms related to the problem and may need medicine or surgery to close the hole.

As with most types of congenital heart disease, no one knows what causes VSDs. This defect often occurs along with other congenital heart malformations.

In adults, interventricular septal defects are a rare, but serious complication of heart attacks. These holes are related to the heart attack and do not result from a birth defect.

• shortness of breath
• breathing fast
• breathing hard
• paleness
• failure to gain weight
• fast heart rate
• pounding heart
• sweating while feeding
• frequent respiratory infections in children

• a chest x-ray to see if there is a large heart with fluid in the lungs
• an ECG shows signs of an enlarged left ventricle
• an echocardiogram -- definitive diagnosis
• a cardiac catheterization (rarely needed)

In mild cases, no treatment is needed, although the baby should be closely followed to ensure that the hole closes properly as the child grows. With congestive heart failure, medications, such as digitalis (digoxin) and diuretics, may be prescribed to control symptoms.

If symptoms continue despite medication, surgery to close the defect with a Gore-tex patch is needed. Some VSDs can be closed with a special device during a catheterization. Treating a VSD that does not have symptoms is controversial, and should be carefully discussed with your health care provider.

• congestive heart failure
• infective endocarditis (bacterial infection of the heart)
• aortic insufficiency (leaking of the valve that separates the left ventricle from the aorta)
• damage to the electrical conduction system of the heart during surgery (causing arrhythmias)
• delayed growth and development (failure to thrive in infancy)
• pulmonary hypertension (high blood pressure in the lungs) leading to failure of the right side of the heart