This website is for informational use only and does not provide any medical advice.

What is ventricular septal defect?

Ventricular septal defect (VSD) is a common structural heart disease that can be present at birth: a hole or defect in the septum (wall) that divides the two lower chambers of the heart (ventricles). In a fetus, the right and left ventricles of the heart are not separate. As the fetus grows, a wall forms and separates the two ventricles. If the wall does not completely form, a hole, or VSD, remains.

Depending on the size of the hole, the heart may pump harder to deliver enough blood to the body, causing higher pressure in the heart and possibly even enlargement. This defect causes blood to flow across the hole from the left pumping chamber (left ventricle) to the right pumping chamber (right ventricle) and into the lungs. In a bigger VSD, this extra blood pumped into the lung arteries can cause lung congestion and permanent damage over time.


In some cases, newborns with this congenital heart defect may be asymptomatic, because it’s not necessary for the heart and lungs to work harder, and the hole eventually can close as the wall continues to grow after birth. Some babies may display symptoms a few weeks after birth. However, if the hole is large, the baby often has symptoms related to heart failure. The most common symptoms of VSD are:

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


The cause of VSD in children is unknown, but genetic factors possibly are involved.


Your doctor can detect a VSD with a stethoscope, which will hear a loud heart murmur.