DefinitionVentricular 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.Alternative NamesVSD; Interventricular septal defectCauses, incidence, and risk factorsBefore 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 one of the most common congenital heart defects. The baby may have no symptoms, and the hole can eventually close as the wall co