Conduction system in VSD

Course of His bundle in VSD: Figure below shows the relationship for membranous VSD and inlet-muscular VSD (Note: Inlet-muscular VSD is different from inlet-VSD in AVSD.

Inlet-muscular VSD has a rim of myocardium separating the VSD margin from the tricuspid valve annulus; whereas, in inlet-VSD in AVSD, AV valve annulus itself if part of the VSD margin.

(See also separate posting for relevant images).

Image from Anderson RH, Wilcox BR. J Card Surgery. 1992;7:17-34.