thaler chapter 1

P Waves, QRS Complexes, T Waves, and Some Straight Lines

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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

Bundle of His

Left bundle branch

Right bundle branch

Purkinje fibers

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