What characterizes an irregular rhythm?

What characterizes an irregular rhythm?

• A. Constant duration between cycles
• B. Lacking a constant duration between paced cardiac cycles
• C. A regular pacing from the SA node
• D. Consistent heart rate

Answer: (B)

An irregular rhythm is characterized by a lack of a constant duration between paced cardiac cycles. This means that the intervals between heartbeats vary, leading to an inconsistent pattern on the EKG. Such irregularities can arise from various conditions, including atrial fibrillation or other arrhythmias, where the electrical impulses in the heart are not firing in a rhythmic, orderly fashion.

In contrast, constant duration between cycles indicates a regular rhythm and is not associated with irregularity. Regular pacing from the SA node suggests a stable sinus rhythm, which also does not align with the concept of an irregular rhythm. Similarly, a consistent heart rate implies a uniform interval between beats, further confirming that the rhythm is regular rather than irregular. Therefore, the defining feature of an irregular rhythm is the variability in the time intervals between successive cardiac cycles.