Which factor contributes to the irregularity of the wandering pacemaker rhythm?

Which factor contributes to the irregularity of the wandering pacemaker rhythm?

• A. Periodic loss of atrial function
• B. Fluctuating pacing from multiple foci
• C. Continuous pacing from a single source
• D. Chronic ischemia

Answer: (B)

The irregularity of the wandering pacemaker rhythm is primarily due to fluctuating pacing from multiple foci in the atria. In a wandering pacemaker, the electrical impulse that triggers heartbeats can originate from different sites in the atrial tissue rather than from a single dominant pacemaker, such as the sinoatrial (SA) node. This results in a variation of the heart rate and rhythm, producing a characteristic irregularity as the impulses vary in timing and origin.

As the impulses are generated from various ectopic atrial foci, the heart's electrical conduction system reflects this variability in pacing, leading to an unstable rhythm. This phenomenon is particularly evident in the EKG as changes in P-wave morphology can often be noticed, corresponding to the different sites of impulse initiation. This characteristic clearly differentiates wandering pacemaker rhythm from other cardiac rhythms that have a consistent pacing source, contributing to its unique presentation.