bundle
of His. The bundle of His proceeds down the
interventricular septum to the inferior border of the membranous
septum where it bifurcates forming the right and left bundle
branches
The depolarization wave leaves the AV node and enters a
compact tract of cardiac conduction system fibers known as the
bundle
of His. The bundle of His proceeds down the
interventricular septum to the inferior border of the membranous
septum where it bifurcates forming the right and left bundle
branches
.
The 
right bundle branch spreads the
electrical impulse to
the right ventricle. The left bundle branch spreads the
electrical impulse to the interventricular septum and left
ventricle. The left bundle branch divides into two branches. The
first branch, the 
anterior superior fascicle,
conducts the
impulse to the anterior and superior segments of the left
ventricle. The second branch, the 
posterior inferior fascicle,
conducts the impulse to the posterior and inferior segments of
the heart.