Ventricular septal defect describes one or more holes in the wall that separates the right and left ventricles of the heart. Ventricular septal defect is one of the most common congenital (present from birth) heart defects. It may occur by itself or with other congenital diseases.

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

Ventricular septal defect is the most common congenital heart defect. The baby may have no symptoms, and the hole can eventually close as the wall continues to grow after birth.

If the hole is large, too much blood will be pumped to the lungs, leading to heart failure. These babies often have symptoms related to heart failure and may need medicine to control the symptoms and surgery to close the hole. The hole can also be closed without surgery, through cardiac catheterization.

The cause of VSD is not yet known. This defect often occurs along with other congenital heart defects.

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

Patients with ventricular septal defects may not have symptoms.

The most common symptoms, however, include:

• Shortness of breath
• Fast breathing
• Hard breathing
• Paleness
• Failure to gain weight
• Fast heart rate
• Pounding heart
• Sweating while feeding
• Frequent respiratory infections

Listening with a stethoscope usually reveals a heart murmur (the sound of the blood crossing the hole). The loudness of the murmur is related to the size of the defect and amount of blood crossing the defect.

Tests may include:

• Chest x-ray -- looks to see if there is a large heart with fluid in the lungs
• ECG -- shows signs of an enlarged left ventricle
• Echocardiogram -- used to make a definite diagnosis
• Cardiac catheterization (rarely needed, unless there are concerns of high blood pressure in the lungs, in which case surgery to close the defect is generally not recommended)
• MRI of the heart -- used to find out how much blood is getting to the lungs