What is a classic EKG feature of atrial flutter?

Atrial flutter is characterized by a distinct "sawtooth pattern" on the electrocardiogram (EKG), commonly referred to as "F-waves" or flutter waves. This pattern is typically observed in the inferior leads (II, III, aVF), where the rapid, regular atrial depolarizations create a series of sharp, sawtooth formations between QRS complexes. The frequency of these flutter waves can vary but often occurs at a rate of approximately 240 to 340 beats per minute.

The presence of this sawtooth pattern is crucial for the diagnosis of atrial flutter, differentiating it from other arrhythmias such as atrial fibrillation or sinus tachycardia, where the EKG findings will differ significantly. This specific waveform generates a hallmark visual characteristic that is often one of the first patterns noticed when evaluating a patient's EKG for signs of atrial flutter.