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.
Ventricular septal defects occur during fetal heart development and are present at birth. During the first weeks after conception, the heart develops from a large tube, dividing into sections that will eventually become the walls and chambers. If a problem occurs during this process, it can create a hole in the ventricular septum.
In some cases, the tendency to develop a VSD may be due to genetic syndromes that cause extra or missing pieces of chromosomes. The vast majority of these defects, though, have no clear cause.
The procedure is safe if done by an experienced doctor at a good cardiac center.