What feature of atrial fibrillation can be identified on an EKG?

Atrial fibrillation is characterized by an irregularly irregular rhythm on the EKG. This means that there is no consistent pattern to the timing of the heartbeats, as opposed to a regular rhythm where the intervals are even. In atrial fibrillation, the absence of discrete P waves is also a key feature; instead, you will see an absence of organized atrial activity, contributing to the irregularity of the QRS complexes. The unpredictable intervals between beats are fundamental in diagnosing atrial fibrillation and can be easily identified upon reviewing the EKG tracing.

In contrast, narrow QRS complexes may appear in various other arrhythmias and do not specifically indicate atrial fibrillation. Regularly spaced P waves would suggest a normal sinus rhythm or another organized rhythm, and distinct ST elevations typically point to conditions such as myocardial infarction rather than atrial fibrillation. Thus, the distinct characteristic of the irregularly irregular rhythm is the hallmark feature of atrial fibrillation on an EKG.