Cleveland Clinic EKG Practice Test 2026 – Complete Exam Prep

Sawtooth flutter waves between QRS complexes point to atrial flutter, caused by a single reentrant circuit in the atria that produces rapid, organized atrial activity. Those regular, multi‑peaked P waves (the flutter waves) give the classic sawtooth appearance, especially in leads II, III, aVF, and V1. The atrial rate is typically around 250–350 beats per minute, and the ventricular rate depends on AV conduction (commonly 2:1, about 150 bpm).

In atrial fibrillation, you’d see an irregularly irregular rhythm with no discrete P waves, just fibrillatory baseline waves. SVT describes a rapid narrow-complex tachycardia with uncertain or hidden P waves rather than a regular sawtooth pattern. Junctional tachycardia can show P waves that are inverted or hidden within the QRS, not the characteristic sawtooth atrial activity.

So the sawtooth P waves fit best with atrial flutter.