What is the order of "normal" electrical conduction of the heart?

The SA node acts as the primary pacemaker and initiates each impulse, which then travels to the AV node where conduction is briefly delayed to allow atrial emptying. The impulse then passes through the Bundle of His, splits into the right and left bundle branches, and finally reaches the Purkinje fibers, which distribute the signal to the ventricular myocardium for coordinated contraction.

The AV node is not the origin of normal electrical conduction; the SA node initiates the impulse and the AV node receives it second.

This sequence incorrectly places the SA node last and reverses the relationship between the bundle branches and Purkinje fibers.

This sequence incorrectly places Purkinje fibers before the bundle branches; the bundle branches must first distribute the impulse to reach the Purkinje fibers.