What does a "sawtooth" pattern on an ECG typically indicate?

A "sawtooth" pattern on an ECG is most commonly associated with atrial flutter. This distinctive pattern, often referred to as "F-waves" or "flutter waves," presents as a series of sharp, jagged peaks that resemble the teeth of a saw, typically appearing in a consistent pattern. The presence of this sawtooth morphology reflects the rapid, organized atrial contractions that characterize atrial flutter, usually occurring at a rate between 240 to 340 beats per minute.

Recognizing this sawtooth pattern helps clinicians differentiate atrial flutter from other arrhythmias, such as ventricular hypertrophy or ventricular tachycardia, which typically do not exhibit this specific waveform. A normal sinus rhythm is characterized by a regular rhythm without such distinctive waveforms. Thus, the identification of the sawtooth appearance is key to diagnosing atrial flutter effectively.