CRAT Practice Exam 2025 – Complete Guide for Test Preparation

The presence of a long pause in a regular rhythm indicates a sinus arrest, where the natural pacing of the heart is interrupted. In a typical sinus rhythm, electrical impulses are generated by the sinoatrial (SA) node at regular intervals, leading to consistent heartbeats. However, during a sinus arrest, the SA node fails to fire for a period, causing one or more heartbeats to be absent, which results in an extended pause in the rhythm.

In this case, the correct choice shows a regular rhythm interrupted by a significant long pause. This reflects the characteristic of sinus arrest, where the rhythm appears regular immediately before the pause, but the gap indicates that the normal pacing was halted, leading to a missed beat.

The other choices do not effectively represent a sinus arrest as they indicate either irregular rhythms or multiple dropped beats without the defining characteristic of the long, singular pause seen in sinus arrest. This distinction is crucial for recognizing and diagnosing various cardiac rhythms in an ECG.