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P Waves, QRS Complexes, T Waves, and Some Straight Lines
23
Ventricular Depolarization
After about one-tenth of a second, the depolarizing wave escapes the
AV node and is swept rapidly down the ventricles along specialized
electrical conducting cells.
This ventricular conducting system has a complex anatomy but
essentially consists of three parts:
1. Bundle of His
2. Bundle branches
3. Terminal
Purkinje fibers
Purkinje fibers
Left bundle branch
Bundle of His
Right bundle branch
The
bundle of His
emerges from the AV node and almost
immediately divides into right and left bundle branches. The
right bundle branch
carries the current down the right side of
the interventricular septum all the way to the apex of the right
ventricle. The
left bundle branch
is more complicated. It divides
into three major fascicles:
1.
Septal fascicle
, which depolarizes the interventricular septum
(the wall of muscle separating the right and left ventricles) in a
left-to-right direction