Certified Rhythm Analysis Technician (CRAT) Practice Exam 2025 - Free CRAT Practice Questions and Study Guide

The rhythm characterized by P waves that have a variety of shapes is the wandering atrial pacemaker. This condition occurs when the site of impulse generation in the atria shifts between various atrial foci, resulting in different shapes and sizes of the P waves seen on an electrocardiogram (ECG). Each focus in the atrium might have a slightly different anatomical position and resting potential, thus producing varying P wave morphologies.

In contrast, atrial flutter usually presents with a classic "sawtooth" pattern of P waves and a regular rhythm, while atrial fibrillation is characterized by irregularly shaped and fibrillatory waves that lack distinct P waves altogether. Sinus arrhythmia involves changes in heart rate with the breathing cycle but typically has uniform P waves since the pacemaker activity originates from the sinus node.

Therefore, in the context of diverse P wave shapes, the wandering atrial pacemaker distinctly stands out as it reflects the variability in pacing sites among similar cardiac events.