Ventricular septal defect is the most common congenital cardiac anomaly (40%), it represents an abnormal communication between the right and left ventricles.

Perimembranous ventricular septal defect is a hole that occurs at the membranous portion of the interventricular septum which is located at the base of the heart between the muscular septum and aortic valves.

It is also referred to as paramembranous or membranous defect.