What rhythm will take place if the AV node assumes the role of the main pacemaker?

When the AV node assumes the role of the main pacemaker, the rhythm that occurs is known as Junctional Rhythm. This situation typically arises when the sinus node, which is the primary pacemaker of the heart, fails to initiate impulses due to conditions such as sinus arrest or if the conduction pathway is obstructed.

In Junctional Rhythm, the impulses are generated from the AV node, which has an intrinsic rate of 40 to 60 beats per minute. This rhythm is characterized by an absence of P waves, or only inverted P waves may be present, reflecting the retrograde depolarization of the atria. The result is a rhythm that is distinct from Normal Sinus Rhythm, characterized by regular cycles initiated by the SA node at a typical rate of 60-100 beats per minute.

Atrial Fibrillation and Ventricular Tachycardia involve more chaotic electrical activity that does not stem from the AV node assuming the role of a main pacemaker. Instead, these rhythms suggest a failure of normal conduction and can lead to compromised cardiac output and other complications. Thus, Junctional Rhythm is specifically identified by the role of the AV node assuming pacemaking function, marking it as the correct choice in this scenario.