8th March 2024

Ventricular Septal Defect

A ventricular septal defect (VSD) is one of the most common congenital cardiac defects (second to bicuspid aortic valve) with a prevalence of about 20-25% of all congenital heart diseases. Males and females are affected equally. Acquired VSDs, e.g., from myocardial infarction, are not discussed here. 

Image Source: Wikimedia Commons (2013). Ventricular septal defect, Licensed under a creative commons licence. Available for free at: https://en.wikipedia.org/wiki/Ventricular_septal_defect (Accessed: 26 January 2024).

There are four subtypes of VSD the commonest of which is membranous VSD, accounting for 80% of defects. They occur within the membranous septum with potential involvement of the tricuspid and aortic valves. 

Muscular VSDs are completely surrounded by muscle. They make up to 15-20% of VSDs. 

5% of VSDs are outlet/infundibular defects located below the aortic and pulmonary valves. They may be associated with aortic regurgitation. 

Inlet VSD, also known as AV canal/AVSD type, typically occur in Down’s syndrome and is found below the AV valves.