A ventricular septal defect (VSD) is an opening or hole in the wall that separates the two lower chambers of the heart. This wall is called the ventricular septum. The hole causes oxygen-rich blood to leak from the left side of the heart to the right side. This causes extra work for the right side of the heart, since more blood than necessary is flowing through the right ventricle to the lungs.
The hole is usually closed with surgery. However, in certain situations, your child's cardiologist and surgeon may think it is best to close the hole with a special device. This procedure is done in the heart catheterization lab.