Inverted P' Waves Occur When The

Inverted P' waves occur when the:

A) atria are firing at a rate of between 250 and 350 beats per minute.
B) impulses arise from the middle of the right atrium.
C) atria are firing in a rapid, chaotic manner stimulating all parts of the atria at the same time.
D) electrical impulse originates in or near the AV junction and travels upward into the atria causing retrograde depolarization.