levels, and the response following cessation of digoxin therapy. As noted above, complete heart block may be difficult to recognize in the presence of AFL. The presence of F waves and a regular rate of the lower pacemaker may lead to the appearance of an uncomplicated AFL. MANAGEMENT The control of ventricular rate and the approach to anticoagulant therapy for patient with atrial flutter is discussed elsewhere. (See "Overview of atrial flutter" and "Embolic risk and the role of anticoagulation in atrial flutter".) Cardioversion in patients with atrial flutter is discussed separately. (See "Restoration of sinus rhythm in atrial flutter".) The approach to the maintenance of sinus rhythm and the impact of electrophysiologic type is discussed separately. (See "Atrial flutter: Maintenance of sinus rhythm" and "Atrial flutter: Maintenance of sinus rhythm", section on 'RF catheter ablation'.) SUMMARY https://www.uptodate.com/contents/electrocardiographic-and-electrophysiologic-features-of-atrial-flutter/print 12/32 7/5/23, 10:39 AM Electrocardiographic and electrophysiologic features of atrial flutter - UpToDate Atrial flutter (AFL) is a supraventricular tachycardia with regular flutter waves and usually an absent isoelectric interval. The rhythm is due to macroreentry, has an excitable gap, and can be transiently entrained and terminated by rapid atrial pacing. Electrocardiographic characteristics include: Biphasic, sawtooth F waves, best seen in the inferior electrocardiogram leads (II, III, aVF), at about 300 beats/min are the classic finding for typical, counterclockwise AFL. The ventricular response is a multiple of the atrial rate, though most frequently is 2:1 with a ventricular rate of 150 beats/min. Flutter waves may sometimes be obscured in the QRS complex in 2:1 conduction. Typical AFL most frequently rotates counterclockwise posterior to the tricuspid valve and uses the critical region of the cavotricuspid isthmus within the circuit. Clockwise, typical AFL uses the same circuit, but rotates in the opposite direction. Atypical AFL is any flutter that does not involve the cavotricuspid isthmus. The flutter wave morphology does not have a characteristic pattern to localize the flutter circuit. Use of UpToDate is subject to the Terms of Use. REFERENCES 1. Wells JL Jr, MacLean WA, James TN, Waldo AL. Characterization of atrial flutter. Studies in man after open heart surgery using fixed atrial electrodes. Circulation 1979; 60:665. 2. Puech P, Latour H, Grolleau R. [Flutter and his limits]. Arch Mal Coeur Vaiss 1970; 63:116. 3. Saoudi N, Cos o F, Waldo A, et al. 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Nakagawa H, Lazzara R, Khastgir T, et al. Role of the tricuspid annulus and the eustachian valve/ridge on atrial flutter. Relevance to catheter ablation of the septal isthmus and a new technique for rapid identification of ablation success. Circulation 1996; 94:407. 27. Cosio FG, L pez-Gil M, Goicolea A, et al. Radiofrequency ablation of the inferior vena cava- tricuspid valve isthmus in common atrial flutter. Am J Cardiol 1993; 71:705. 28. Schilling RJ, Peters NS, Goldberger J, et al. Characterization of the anatomy and conduction velocities of the human right atrial flutter circuit determined by noncontact mapping. J Am Coll Cardiol 2001; 38:385. 29. Shah DC, Ja s P, Ha ssaguerre M, et al. Three-dimensional mapping of the common atrial flutter circuit in the right atrium. Circulation 1997; 96:3904. 30. Dixit S, Lavi N, Robinson M, et al. Noncontact electroanatomic mapping to characterize typical atrial flutter: participation of right atrial posterior wall in the reentrant circuit. J Cardiovasc Electrophysiol 2011; 22:422. 31. Maury P, Duparc A, Hebrard A, et al. Prevalence of typical atrial flutter with reentry circuit posterior to the superior vena cava: use of entrainment at the atrial roof. Europace 2008; 10:190. 32. Yang Y, Cheng J, Bochoeyer A, et al. Atypical right atrial flutter patterns. Circulation 2001; 103:3092. 33. Yang Y, Varma N, Badhwar N, et al. Prospective observations in the clinical and electrophysiological characteristics of intra-isthmus reentry. J Cardiovasc Electrophysiol https://www.uptodate.com/contents/electrocardiographic-and-electrophysiologic-features-of-atrial-flutter/print 15/32 7/5/23, 10:39 AM Electrocardiographic and electrophysiologic features of atrial flutter - UpToDate 2010; 21:1099. 34. Cheng J, Cabeen WR Jr, Scheinman MM. Right atrial flutter due to lower loop reentry: mechanism and anatomic substrates. Circulation 1999; 99:1700. 35. Tai CT, Huang JL, Lin YK, et al. Noncontact three-dimensional mapping and ablation of upper loop re-entry originating in the right atrium. J Am Coll Cardiol 2002; 40:746. 36. Wasmer K, M nnig G, Bittner A, et al. Incidence, characteristics, and outcome of left atrial tachycardias after circumferential antral ablation of atrial fibrillation. Heart Rhythm 2012; 9:1660. 37. Chae S, Oral H, Good E, et al. Atrial tachycardia after circumferential pulmonary vein ablation of atrial fibrillation: mechanistic insights, results of catheter ablation, and risk factors for recurrence. J Am Coll Cardiol 2007; 50:1781. 38. Bai R, Di Biase L, Mohanty P, et al. Ablation of perimitral flutter following catheter ablation of atrial fibrillation: impact on outcomes from a randomized study (PROPOSE). J Cardiovasc Electrophysiol 2012; 23:137. 39. Miyazaki S, Shah AJ, Hocini M, et al. Recurrent spontaneous clinical perimitral atrial tachycardia in the context of atrial fibrillation ablation. Heart Rhythm 2015; 12:104. 40. Zhang J, Tang C, Zhang Y, et al. Electroanatomic characterization and ablation outcome of nonlesion related left atrial macroreentrant tachycardia in patients without obvious structural heart disease. J Cardiovasc Electrophysiol 2013; 24:53. 41. Fukamizu S, Sakurada H, Hayashi T, et al. Macroreentrant atrial tachycardia in patients without previous atrial surgery or catheter ablation: clinical and electrophysiological characteristics of scar-related left atrial anterior wall reentry. J Cardiovasc Electrophysiol 2013; 24:404. 42. Stambler BS, Ellenbogen KA. Elucidating the mechanisms of atrial flutter cycle length variability using power spectral analysis techniques. Circulation 1996; 94:2515. 43. Yuniadi Y, Tai CT, Lee KT, et al. A new electrocardiographic algorithm to differentiate upper loop re-entry from reverse typical atrial flutter. J Am Coll Cardiol 2005; 46:524. 44. Gerstenfeld EP, Dixit S, Bala R, et al. Surface electrocardiogram characteristics of atrial tachycardias occurring after pulmonary vein isolation. Heart Rhythm 2007; 4:1136. 45. Knight BP, Michaud GF, Strickberger SA, Morady F. Electrocardiographic differentiation of atrial flutter from atrial fibrillation by physicians. J Electrocardiol 1999; 32:315. 46. Khairy P, Stevenson WG. Catheter ablation in tetralogy of Fallot. Heart Rhythm 2009; 6:1069. 47. Chugh A, Latchamsetty R, Oral H, et al. Characteristics of cavotricuspid isthmus-dependent atrial flutter after left atrial ablation of atrial fibrillation. Circulation 2006; 113:609. https://www.uptodate.com/contents/electrocardiographic-and-electrophysiologic-features-of-atrial-flutter/print 16/32 7/5/23, 10:39 AM Electrocardiographic and electrophysiologic features of atrial flutter - UpToDate 48. Baranchuk A, Kang J. Pseudo-atrial flutter: Parkinson tremor. Cardiol J 2009; 16:373. 49. Chakravarthy M, Mattur K, Raghavan R, et al. Artifactual 'atrial flutter' caused by a continuous passive motion device after total knee replacement. Anaesth Intensive Care 2009; 37:1038. 50. Hoffmayer KS, Goldschlager N. Pseudoatrial flutter. J Electrocardiol 2008; 41:201. Topic 1061 Version 26.0 https://www.uptodate.com/contents/electrocardiographic-and-electrophysiologic-features-of-atrial-flutter/print 17/32 7/5/23, 10:39 AM Electrocardiographic and electrophysiologic features of atrial flutter - UpToDate GRAPHICS Reentrant circuit of typical atrial flutter within the right atrium Schematic representation of reentrant circuit (red arrow) of typical (type 1) atrial flutter. The reentrant impulse rotates in a counterclockwise direction around the tricuspid annulus. The crista terminalis (CT) and eustacian ridge (ER) serve as lines of block, preventing the impulse from short-circuiting the annulus. Ablation is performed in the isthmus between the IVC and TA, which is an obligatory part of the circuit. SVC: superior vena cava; CS: coronary sinus; IVC: inferior vena cava; FO: foramen ovale Graphic 52904 Version 5.0 https://www.uptodate.com/contents/electrocardiographic-and-electrophysiologic-features-of-atrial-flutter/print 18/32 7/5/23, 10:39 AM Electrocardiographic and electrophysiologic features of atrial flutter - UpToDate 12-lead electrocardiogram showing atrial flutter in preexcitation syndrome Atrial flutter is generated within the right atrium and the atrial impulses in this case are conducted to the ventricle by an accessory pathway. There is 1:1 conduction with a ventricular rate of 300 beats/min. The QRS complexes are widened or aberrant and have a bundle branch block morphology and a left axis deviation, suggesting the presence of an atriofascicular (Mahaim) accessory pathway. Courtesy of Morton Arnsdorf, MD. Graphic 78602 Version 4.0 Normal ECG https://www.uptodate.com/contents/electrocardiographic-and-electrophysiologic-features-of-atrial-flutter/print 19/32 7/5/23, 10:39 AM Electrocardiographic and electrophysiologic features of atrial flutter - UpToDate Normal electrocardiogram showing normal sinus rhythm at a rate of 75 beats/minute, a PR interval of 0.14 seconds, a QRS interval of 0.10 seconds, and a QRS axis of approximately 75 . Courtesy of Ary Goldberger, MD. Graphic 76183 Version 4.0 https://www.uptodate.com/contents/electrocardiographic-and-electrophysiologic-features-of-atrial-flutter/print 20/32 7/5/23, 10:39 AM Electrocardiographic and electrophysiologic features of atrial flutter - UpToDate Revised (2018) Vaughan Williams classification of antiarrhythmic drugs abridged table Class 0 (HCN channel blockers) Ivabradine Class I (voltage-gated Na+ channel blockers) Class Ia (intermediate dissociation): Quinidine, ajmaline, disopyramide, procainamide Class Ib (rapid dissociation): Lidocaine, mexilitine Class Ic (slow dissociation): Propafenone, flecainide Class Id (late current): Ranolazine Class II (autonomic inhibitors and activators) Class IIa (beta blockers): Nonselective: carvedilol, propranolol, nadolol Selective: atenolol, bisoprolol, betaxolol, celiprolol, esmolol, metoprolol Class IIb (nonselective beta agonists): Isoproterenol Class IIc (muscarinic M2 receptor inhibitors): Atropine, anisodamine, hyoscine, scopolamine Class IId (muscarinic M2 receptor activators): Carbachol, pilocarpine, methacholine, digoxin Class IIe (adenosine A1 receptor activators): Adenosine Class III (K+ channel blockers and openers) Class IIIa (voltage dependent K+ channel blockers): Ambasilide, amiodarone, dronedarone, dofetilide, ibutilide, sotalol, vernakalant Class IIIb (metabolically dependent K+ channel openers): https://www.uptodate.com/contents/electrocardiographic-and-electrophysiologic-features-of-atrial-flutter/print 21/32 7/5/23, 10:39 AM Electrocardiographic and electrophysiologic features of atrial flutter - UpToDate Nicorandil, pinacidil Class IV (Ca++ handling modulators) Class IVa (surface membrane Ca++ channel blockers): Bepridil, diltiazem, verapamil Class IVb (intracellular Ca++ channel blockers): Flecainide, propafenone Class V (mechanosensitive channel blockers): No approved medications Class VI (gap junction channel blockers) No approved medications Class VII (upstream target modulators) Angiotensin converting enzyme inhibitors Angiotensin receptor blockers Omega-3 fatty acids Statins HCN: hyperpolarization-activated cyclic nucleotide-gated; Na: sodium; K: potassium; Ca: calcium. Graphic 120433 Version 3.0 https://www.uptodate.com/contents/electrocardiographic-and-electrophysiologic-features-of-atrial-flutter/print 22/32 7/5/23, 10:39 AM Electrocardiographic and electrophysiologic features of atrial flutter - UpToDate Typical atrial flutter Electrocardiogram in type I counterclockwise typical atrial flutter. The biphasic flutter (F) waves are prominently negative (lead II) in counterclockwise typical flutter. The patient is on a beta-blocker which explains the predominant 4:1 conduction pattern. Graphic 74395 Version 4.0 https://www.uptodate.com/contents/electrocardiographic-and-electrophysiologic-features-of-atrial-flutter/print 23/32 7/5/23, 10:39 AM Electrocardiographic and electrophysiologic features of atrial flutter - UpToDate Reverse typical atrial flutter Electrocardiogram in type I clockwise typical atrial flutter. The flutter waves are positive in the inferior leads (II, III, aVF), with a more sinusoidal appearance and a broad negative F wave in V1. Graphic 81563 Version 3.0 https://www.uptodate.com/contents/electrocardiographic-and-electrophysiologic-features-of-atrial-flutter/print 24/32 7/5/23, 10:39 AM Electrocardiographic and electrophysiologic features of atrial flutter - UpToDate Electrocardiogram in lower loop reentry flutter Arrows point to flutter waves, which are positive in V1 and subtle but negative in the inferior leads. Graphic 106118 Version 1.0 https://www.uptodate.com/contents/electrocardiographic-and-electrophysiologic-features-of-atrial-flutter/print 25/32 7/5/23, 10:39 AM Electrocardiographic and electrophysiologic features of atrial flutter - UpToDate Electrocardiogram from a patient with an atriotomy-related right atrial flutter a mitral valve repair On electrophysiology study, the circuit was found to be wrapping around the atriotomy scar. The arrows poin flutter waves, which are negative in the inferior leads. Graphic 106119 Version 1.0 https://www.uptodate.com/contents/electrocardiographic-and-electrophysiologic-features-of-atrial-flutter/print 26/32 7/5/23, 10:39 AM Electrocardiographic and electrophysiologic features of atrial flutter - UpToDate Electrocardiogram of an atypical left atrial flutter occurring through a scar on t anterior septum in a patient with a prior atrial fibrillation ablation The arrows show the flutters waves, which are positive in V1. Graphic 106120 Version 1.0 https://www.uptodate.com/contents/electrocardiographic-and-electrophysiologic-features-of-atrial-flutter/print 27/32 7/5/23, 10:39 AM Electrocardiographic and electrophysiologic features of atrial flutter - UpToDate Electrocardiogram of an atypical roof dependent left atrial flutter after an atria fibrillation ablation The arrows show positive flutter waves in V1 indicative of a left atrial focus. Flutter waves are isoelectric in th leads. Graphic 106121 Version 2.0 https://www.uptodate.com/contents/electrocardiographic-and-electrophysiologic-features-of-atrial-flutter/print 28/32 7/5/23, 10:39 AM Electrocardiographic and electrophysiologic features of atrial flutter - UpToDate Electrocardiogram of a patient with clockwise mitral annular flutter The arrows show the flutter waves, which are low amplitude and negative in the inferior leads. They are posit 3, but become negative and then positive in V4-6. Graphic 106122 Version 1.0 https://www.uptodate.com/contents/electrocardiographic-and-electrophysiologic-features-of-atrial-flutter/print 29/32 7/5/23, 10:39 AM Electrocardiographic and electrophysiologic features of atrial flutter - UpToDate Atrial flutter at a rate of 250 beats/minute with 2:1 AV conduction in the presence of left bundle branch block Although every other flutter wave can be seen at the end of the T wave in the first part of the tracing (arrows), a sinus mechanism cannot be excluded. The flutter waves become clearly apparent after carotid sinus massage is applied to slow conduction through the AV node, thereby increasing the degree of AV block. AV: atrioventricular Courtesy of Morton Arnsdorf, MD. Graphic 76876 Version 3.0 Normal rhythm strip Normal rhythm strip in lead II. The PR interval is 0.15 sec and the QRS duration is 0.08 sec. Both the P and T waves are upright. Courtesy of Morton F Arnsdorf, MD. Graphic 59022 Version 3.0 https://www.uptodate.com/contents/electrocardiographic-and-electrophysiologic-features-of-atrial-flutter/print 30/32 7/5/23, 10:39 AM Electrocardiographic and electrophysiologic features of atrial flutter - UpToDate Atrial flutter RA recording Atrial flutter which is inapparent in lead I (upper panel); suggested by prominent negativity in lead II (arrows, middle panel), which could also represent biphasic T waves; and documented by right atrial recording, which shows prominent negative deflections (arrows, lower panel). Courtesy of Morton Arnsdorf, MD. Graphic 54591 Version 2.0 Normal rhythm strip Normal rhythm strip in lead II. The PR interval is 0.15 sec and the QRS duration is 0.08 sec. Both the P and T waves are upright. Courtesy of Morton F Arnsdorf, MD. Graphic 59022 Version 3.0 https://www.uptodate.com/contents/electrocardiographic-and-electrophysiologic-features-of-atrial-flutter/print 31/32 7/5/23, 10:39 AM Electrocardiographic and electrophysiologic features of atrial flutter - UpToDate Contributor Disclosures Jordan M Prutkin, MD, MHS, FHRS No relevant financial relationship(s) with ineligible companies to disclose. Peter J Zimetbaum, MD Consultant/Advisory Boards: Abbott Medical [Lead extraction]. All of the relevant financial relationships listed have been mitigated. Ary L Goldberger, MD Other Financial Interest: Elsevier book royalties [Clinical electrocardiography]. All of the relevant financial relationships listed have been mitigated. Nisha Parikh, MD, MPH No relevant financial relationship(s) with ineligible companies to disclose. Contributor disclosures are reviewed for conflicts of interest by the editorial group. When found, these are addressed by vetting through a multi-level review process, and through requirements for references to be provided to support the content. Appropriately referenced content is required of all authors and must conform to UpToDate standards of evidence. Conflict of interest policy https://www.uptodate.com/contents/electrocardiographic-and-electrophysiologic-features-of-atrial-flutter/print 32/32