What feature distinguishes atrial flutter on an EKG?

Atrial flutter is characterized by a distinctive sawtooth pattern of F waves, often referred to as “flutter waves.” This pattern is most commonly seen in the inferior leads (II, III, aVF) and demonstrates a regular and continuous rhythmic activity that resembles a “sawtooth” shape. This feature results from rapid reentrant circuits within the atria, leading to a regular atrial contraction but can also manifest as an organized pattern clearly visible on the EKG.

Option C is correct because the identification of these flutter waves is crucial in distinguishing atrial flutter from other arrhythmias, such as atrial fibrillation, which would show irregularly undulating baseline without clear flutter waves. The clear sawtooth appearance in atrial flutter allows for easy recognition of this specific arrhythmia on an EKG reading.