Atrial flutter vs Atrial fibrillation
How to tell Atrial flutter and Atrial fibrillation apart when a board question makes them look alike.
Flutter has organized sawtooth atrial activity; fibrillation has no organized P/flutter waves and is irregularly irregular.
Side by side
Organized atrial macroreentry with sawtooth flutter waves, often in inferior leads, with fixed or variable AV block.
Disorganized atrial activity with no discrete P waves and irregularly irregular ventricular rhythm.
Atrial flutter is usually a reentrant circuit, often around the tricuspid annulus.
Atrial fibrillation is chaotic atrial activation causing loss of organized atrial contraction.
Sawtooth flutter waves and ventricular rates related to conduction ratios point flutter.
Irregularly irregular rhythm without organized atrial waves points AF.
The trap
Flutter with variable block can be irregular, so look for repeating flutter waves before calling AF.
Watch it explained
The repair move
For atrial rhythms, decide whether atrial activity is organized before judging rhythm regularity.
Try a free question
CoreAn ECG shows regular narrow-complex tachycardia with sawtooth flutter waves best seen in the inferior leads and 2:1 AV conduction. Which rhythm is most likely?
Show answer and explanation
Answer: A. Atrial flutter. Atrial flutter has organized atrial activity with sawtooth flutter waves, often with fixed or variable AV block.
Why the other choices are tempting
- B. Atrial fibrillation is irregularly irregular without organized P or flutter waves.
- C. MAT has at least three P-wave morphologies and irregular rhythm.
- D. AVNRT is a regular narrow tachycardia without sawtooth flutter waves.
- E. VT is wide-complex ventricular rhythm.
Flashcards
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What is the fastest separator for Atrial flutter vs Atrial fibrillation?
Flutter has organized sawtooth atrial activity; fibrillation has no organized P/flutter waves and is irregularly irregular.
What clue should make you choose Atrial flutter?
Organized atrial macroreentry with sawtooth flutter waves, often in inferior leads, with fixed or variable AV block.
Quick answers
What is the fastest way to tell Atrial flutter from Atrial fibrillation?
Flutter has organized sawtooth atrial activity; fibrillation has no organized P/flutter waves and is irregularly irregular.
What is the key clue for Atrial flutter?
Organized atrial macroreentry with sawtooth flutter waves, often in inferior leads, with fixed or variable AV block.
What is the key clue for Atrial fibrillation?
Disorganized atrial activity with no discrete P waves and irregularly irregular ventricular rhythm.
What is the common trap with Atrial flutter vs Atrial fibrillation?
Flutter with variable block can be irregular, so look for repeating flutter waves before calling AF.