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.

VSD enlargement (Surgery)

To enlarge the VSD without causing AV block...

D-loop ventricles - Raise the roof (Enlarge VSD in anterior-superior direction)

L-loop ventricles - Lower the floor (Enlarge VSD in posterior-inferior direction)

Without injuring the aortic valve in the process!

Conduction System - Normal Heart vs. AVSD (One aspect of it)

Images from Kirklin/Barratt-Boyes Cardiac Surgery 3rd edition (2003)

AVSD (p 813)
Normal Heart (p 15)


Conduction system in VSDs:
Figure below shows the AV node and His bundle relationship to membranous VSD and inlet-muscular VSD. Note: Inlet-muscular VSD is different from inlet-VSD in AVSD. The latter is shown in the first figure above.
(From Anderson RH, Wilcox BR. J Cardiac Surg. 1992;7:17-34)