During which condition might you see a "sawtooth" pattern on an ECG?

The "sawtooth" pattern on an ECG is characteristic of atrial flutter, where there is a rapid reentrant circuit typically around the right atrium. This pattern, often referred to as "F-waves," appears in a distinctive sawtooth formation, primarily visible in the inferior leads (II, III, and aVF) and often termed "typical atrial flutter."

During atrial flutter, the atria contract at a rapid rate (often around 250-350 beats per minute), creating this specific waveform appearance. Unlike atrial fibrillation, which presents with irregularly spaced QRS complexes due to chaotic electrical activity in the atria without defined waveforms, atrial flutter maintains a more organized, regular rhythm that results in this sawtooth pattern.

Conditions like ventricular tachycardia and normal sinus rhythm do not display this specific sawtooth pattern; they present with different morphologies on the ECG. In normal sinus rhythm, you would see regular P waves followed by QRS complexes and a consistent rhythm, while ventricular tachycardia typically shows a wide complex QRS without the regular pattern seen in atrial flutter. Thus, the presence of a "sawtooth" pattern firmly associates with atrial