Atrial flutter — an educational nurse reference.
The sawtooth flutter waves, why conduction ratios matter, and how to tell flutter from AFib on a strip.
Recognizing this rhythm at the bedside means matching pattern, intervals, and clinical context. This page covers the educational pattern; calipers and your clinical judgment carry it across the line.
What RN PocketPal does
Identifying traits
- Atrial rate: ~250–350/min (classically ~300), organized.
- Flutter (F) waves: sawtooth baseline, best seen in II, III, aVF.
- Ventricular rate: depends on conduction ratio (2:1 ≈ 150, 3:1 ≈ 100, 4:1 ≈ 75).
- Rhythm: regular when the conduction ratio is fixed; irregular when variable.
- QRS: usually narrow unless aberrancy.
Verify with
- Look for the sawtooth pattern along the baseline — flutter waves march through the QRS.
- A regular narrow-complex tach at exactly ~150 should make you look hard for 2:1 flutter.
- 12-lead and the clinical team for rate/rhythm decisions and anticoagulation.
Who it’s for
For Nurses and nursing students learning rhythm interpretation.
Ten seconds of this rhythm, from a real recording
What to notice in this strip
Look at the baseline between the QRS complexes rather than at the complexes themselves. The atrial activity here is organised and repetitive, unlike the chaotic baseline of fibrillation.
Counting the rate on a strip like this
The strip above is exactly ten seconds, so counting every QRS complex across it and multiplying by six gives the rate — the method that works whether the rhythm is regular or not. When the rhythm is regular, you can shortcut it: divide 300 by the number of large squares between two R waves.
Rhythms this gets confused with
Known-answer practice — RN PocketPal does not interpret your patient's monitor. To work through strips with the answer revealed after you commit, open Rhythm Practice.
Strip source: MIT-BIH Atrial Fibrillation Database v1.0.0, record 04043. Lead/channel 0, 10-second window, resampled to 100 Hz, zero-mean/unit-variance normalized for bundled practice use. Used under the Open Data Commons Attribution License v1.0. Goldberger AL, Amaral LAN, Glass L, Hausdorff JM, Ivanov PCh, Mark RG, Mietus JE, Moody GB, Peng C-K, Stanley HE. PhysioBank, PhysioToolkit, and PhysioNet. Circulation. 2000;101(23):e215-e220.
Frequently asked questions
- How do I tell atrial flutter from AFib?
- Flutter shows organized sawtooth F waves at a regular atrial rate (~300/min); AFib has a chaotic fibrillatory baseline with no organized atrial activity and an irregularly irregular ventricular response. When unsure, a 12-lead and your clinician settle it.
- Why is a rate of 150 a clue?
- 2:1 flutter conducts an atrial rate of ~300 down to a ventricular rate of ~150. A regular narrow tachycardia sitting right at 150 is classic for 2:1 flutter until proven otherwise.
- Does flutter carry stroke risk like AFib?
- Atrial flutter carries thromboembolic risk and anticoagulation implications similar to AFib. Those decisions belong to the clinical team — RN PocketPal does not make them.
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Reviewed by RN PocketPal Clinical Team, RN. Last reviewed .