Sawtooth waves best seen in leads II, III, aVF indicate which rhythm?

Sawtooth waves best seen in leads II, III, aVF indicate which rhythm?

• A. Atrial fibrillation.
• B. Atrial tachycardia.
• C. Atrial flutter.
• D. Ventricular tachycardia.

Answer: (C)

Sawtooth waves reflect a rapid, organized atrial rhythm. When these F waves are best seen in the inferior leads (II, III, aVF), they indicate atrial flutter. The atria depolarize at about 250–350 times per minute in a regular pattern, creating those uniform sawtooth deflections between the QRS complexes. The ventricular rate depends on how many atrial impulses are conducted through the AV node, often around 150 bpm with typical 2:1 conduction, though other conduction ratios can occur. This pattern distinguishes flutter from other rhythms: atrial fibrillation lacks discrete P or F waves and is irregularly irregular; atrial tachycardia shows a defined P wave morphology before each QRS; ventricular tachycardia presents wide, abnormal QRS complexes with little to no visible atrial activity.

Sawtooth waves reflect a rapid, organized atrial rhythm. When these F waves are best seen in the inferior leads (II, III, aVF), they indicate atrial flutter. The atria depolarize at about 250–350 times per minute in a regular pattern, creating those uniform sawtooth deflections between the QRS complexes. The ventricular rate depends on how many atrial impulses are conducted through the AV node, often around 150 bpm with typical 2:1 conduction, though other conduction ratios can occur.

This pattern distinguishes flutter from other rhythms: atrial fibrillation lacks discrete P or F waves and is irregularly irregular; atrial tachycardia shows a defined P wave morphology before each QRS; ventricular tachycardia presents wide, abnormal QRS complexes with little to no visible atrial activity.