Atrial flutter

American College of Cardiology/American Heart Association/Heart Rhythm Society classification of atrial flutter/atrial tachycardias[4]Page RL, Joglar JA, Caldwell MA, et al. 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia. J Am Coll Cardiol. 2016 Apr 5;67(13):e27-115. https://content.onlinejacc.org/article.aspx?articleid=2443667 http://www.ncbi.nlm.nih.gov/pubmed/26409259?tool=bestpractice.com

Atrial flutter is a macroreentrant atrial tachycardia with constant P wave/flutter morphology with a rate usually >250 bpm. It is distinguishable from focal atrial tachycardia, which has discrete P waves with an intervening isoelectric segment. Focal atrial tachycardia is caused mechanistically by micro-reentry or increased automaticity and generally has atrial rates in the range of 100-250 bpm.

Cavotricuspid isthmus dependent (typical atrial flutter):

• Counterclockwise atrial flutter with ECG flutter waves characterized by:

  • Negative deflection in leads II, III, aVF

  • Positive deflection in lead V1.

• Clockwise atrial flutter (reverse typical atrial flutter) with ECG flutter waves characterized by:

  • Positive deflection in leads II, III, aVF

  • Negative deflection in lead V1.

Non cavotricuspid isthmus dependent (atypical atrial flutter):

• Re-entry that does not depend upon conduction through the cavotricuspid isthmus

• Circuit is typically defined by atrial scars due to prior heart surgery, ablations, or idiopathic causes

• Location determines ablation approach and risks

• Multiple sites of re-entry may be present

• Can occur in both the left and right atria.