Ventricular Septal Defect - A ventricular septal defect (VSD) is a heart malformation present at birth. Any condition that is present at birth can also be termed a "congenital" condition. A VSD, therefore, is a type of congenital heart disease (CHD). The heart with a VSD has a hole in the wall (the septum) between its two lower chambers (the ventricles). .