Which rhythm is characterized by a sawtooth P wave pattern?

• A. Atrial fibrillation
• B. Normal sinus rhythm
• C. Atrial flutter
• D. Ventricular tachycardia

Answer: (C)

Sawtooth flutter waves point to atrial flutter, which is caused by a reentrant circuit in the atria. In this rhythm, the atrial activity is rapid and organized into flutter waves rather than discrete P waves, giving a distinctive sawtooth pattern on the ECG. The atrial rate is typically about 250–350 beats per minute, and the ventricular rate depends on AV conduction (common patterns are 2:1 or 4:1 conduction), producing a regular rhythm with the characteristic sawtooth appearance most visible in leads II, III, and aVF (and sometimes V1).

This pattern helps distinguish atrial flutter from other rhythms: atrial fibrillation shows an irregularly irregular rhythm with no organized P or flutter waves; normal sinus rhythm has clear, normal P waves before every QRS; ventricular tachycardia is a rapid, wide-complex rhythm with no organized atrial activity or sawtooth flutter waves.