Bundle of His
The bundle of His is a part of the electrical system of the heart. It is a collection of cells that carry electrical signals from the AV node to the bundle branches.
The electrical system that controls the heartbeat is made up of several parts that signal the heart muscle to contract. The SA node initiates the sequence, causing the atria, or upper chambers of the heart, to contract. The electrical current then travels through the AV node, bundle of His, bundle branches, and Purkinje fibers. This causes the ventricles, the lower chambers of the heart, to contract. The normal sequential flow of electrical signals produce a normal heartbeat.