Atrial flutter

Atrial flutter is typically characterised on the ECG by flutter waves, which are a saw-tooth pattern of atrial activation, most prominent in leads II, III, aVF, and V1.

Atrial rates are typically above 250 bpm and up to 320 bpm.

Ventricular rates range from 120 to 160 bpm, and most characteristically 150 bpm, because an associated 2:1 atrioventricular block is common.

This rhythm is commonly associated with atrial fibrillation, into which it may degenerate. Atrial fibrillation may also convert to atrial flutter. Because of alterations in atrial activation, the ECG often fluctuates between both rhythms in the same patient.

If a patient is haemodynamically unstable, they should be given emergency electrical cardioversion.

If a patient is haemodynamically stable, the first-line treatment is rate control and management of the underlying cause.

If the rhythm persists in a haemodynamically stable patient, despite rate control and treatment of the underlying cause (or in the absence of a reversible cause), electrical cardioversion is used to terminate the arrhythmia.

If electrical cardioversion is unavailable or not acceptable to the patient, pharmacological cardioversion may be attempted.

Typical atrial flutter (anticlockwise cavotricuspid isthmus-dependent atrial flutter) is a macro re-entrant atrial tachycardia with atrial rates usually above 250 bpm up to 320 bpm. It results from organised electrical activity in which large areas of the atrium take part in the re-entrant circuit. The typical form depends on the so-called cavotricuspid isthmus for part of the circuit: tricuspid annulus as the anterior boundary and the crista terminalis/eustachian ridge as the posterior boundary, as well as the endocardial cavity of the right atrium. The term anticlockwise refers to the direction of activation when the tricuspid annulus is viewed en face, whereby activation occurs up the septum, down the right atrial free wall in an anticlockwise fashion. Characteristic features on ECG are negatively directed saw-tooth atrial deflections (f waves) seen in leads II, III, and aVF, with positively directed deflections in lead V1.[1]Estes NA 3rd, Halperin JL, Calkins H, et al; American College of Cardiology; American Heart Association Task Force on Performance Measures; Physician Consortium for Performance Improvement. ACC/AHA/Physician Consortium 2008 clinical performance measures for adults with nonvalvular atrial fibrillation or atrial flutter. J Am Coll Cardiol. 2008 Feb 26;51(8):865-84. http://www.ncbi.nlm.nih.gov/pubmed/18294574?tool=bestpractice.com

[Figure caption and citation for the preceding image starts]: Typical atrial flutter with variable (3 to 4:1) blockFrom the collection of Dr K.C. Wu [Citation ends].

This rhythm is closely related to atrial fibrillation.[2]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 [3]Saoudi N, Cosío F, Waldo A, et al. A classification of atrial flutter and regular atrial tachycardia according to electrophysiological mechanisms and anatomical bases; a statement from a joint expert group from the Working Group of Arrhythmias of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology. Eur Heart J. 2001 Jul;22(14):1162-82. http://www.ncbi.nlm.nih.gov/pubmed/11440490?tool=bestpractice.com [4]Lévy S, Camm AJ, Saksena S, et al. International consensus on nomenclature and classification of atrial fibrillation; a collaborative project of the Working Group on Arrhythmias and the Working Group on Cardiac Pacing of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology. Europace. 2003 Apr;5(2):119-22. https://academic.oup.com/europace/article/5/2/119/2344543 http://www.ncbi.nlm.nih.gov/pubmed/12633634?tool=bestpractice.com

[Figure caption and citation for the preceding image starts]: Atrial fibrillationFrom the collection of Dr K.C. Wu [Citation ends].[Figure caption and citation for the preceding image starts]: Atrial flutter typically involves a circuit in the right atriumFrom: Cox D, Dougall H. Student BMJ. 2001;9:399-442; used with permission [Citation ends].