Version July 2025
INTRODUCTION —
Atrial flutter (AFL) is a supraventricular arrhythmia that can cause bothersome symptoms and promote atrial thrombus formation with the potential for systemic embolization. Restoration of sinus rhythm improves symptoms and decreases the risk of embolization if recurrence does not occur. (See "Atrial flutter: Overview of diagnosis and management", section on 'Clinical manifestations' and "Atrial flutter: Risk of thromboembolism and role of anticoagulation", section on 'Thromboembolic risk'.)
Issues related to the indications and therapeutic options for the restoration of sinus rhythm in AFL will be reviewed here. Causes of AFL, rate control therapy, the maintenance of sinus rhythm after cardioversion, and the role of anticoagulation in AFL are discussed separately. (See "Control of ventricular rate in atrial flutter" and "Atrial flutter: Maintenance of sinus rhythm" and "Atrial flutter: Risk of thromboembolism and role of anticoagulation".)
RATIONALE —
AFL is a relatively common supraventricular arrhythmia that is characterized by rapid, regular atrial depolarizations at a characteristic rate of approximately 300 beats/min. (See "ECG tutorial: Atrial and atrioventricular nodal (supraventricular) arrhythmias", section on 'Atrial fibrillation and atrial flutter' and "Atrial flutter: Overview of diagnosis and management".)
In the absence of rate slowing drugs or atrioventricular (AV) nodal disease, most commonly, every other beat is conducted through the AV node so that the ventricular rate is usually around 150 beats per minute. Because of the rapid rate, the patient may present with symptoms of palpitations, chest pain, dyspnea, fatigue, dizziness, and rarely hemodynamic shock, similar to patients with atrial fibrillation (AF) with a rapid ventricular response. (See "Hemodynamic consequences of atrial fibrillation and cardioversion to sinus rhythm", section on 'Adverse hemodynamics in AF'.)
In addition to improving symptoms, the restoration of sinus rhythm prevents the potential for the development of tachycardia-mediated cardiomyopathy and somewhat reduces the risk of systemic embolization. (See "Arrhythmia-induced cardiomyopathy", section on 'Atrial fibrillation and atrial flutter' and "Atrial flutter: Risk of thromboembolism and role of anticoagulation", section on 'Thromboembolic risk'.)
AFL is often an electrically unstable rhythm, meaning that it frequently degenerates into the more disorganized AF or reverts to sinus rhythm within hours or days, though it can also be chronic. Spontaneous reversion to a sinus mechanism may occur after predisposing problems are improved, such as decompensated heart failure (HF) or the sequelae of cardiac surgery.
In patients who do not spontaneously convert to sinus rhythm, rate slowing with drugs may be considered a therapeutic option. The ventricular rate is frequently difficult to control, however, as most medications are ineffective for rate slowing and for many patients it is not worth attempting as a long-term alternative to rhythm control. Rate control may be appropriate for patients who are reluctant to undergo cardioversion or who have no or minimal symptoms. (See "Control of ventricular rate in atrial flutter".)
For those patients in whom a decision has been made to restore sinus rhythm, most can be cardioverted successfully without complication. Factors that predict spontaneous reversion to sinus rhythm or a successful cardioversion are similar to those for AF and include a left atrial size less than 4.5 to 5 cm, little or no HF or left ventricular dysfunction, no underlying reversible cause such as hyperthyroidism, myocardial infarction, or pulmonary embolism, and AFL of recent onset. (See "Atrial fibrillation: Cardioversion", section on 'Reasons not to perform cardioversion'.)
INDICATIONS —
Most patients with AFL who do not undergo spontaneous conversion to sinus rhythm should undergo cardioversion. The following are indications for urgent cardioversion:
●Patients with AFL who have a rapid ventricular rate and significant hemodynamic compromise (hypotension or HF) should undergo urgent cardioversion. In patients with AFL and hemodynamic compromise, but with a controlled ventricular rate (eg, ≤100 beats/min), explanations for hemodynamic instability other than the AFL should be sought. Restoration of sinus rhythm in these patients may not necessarily improve the clinical status.
●Most patients with AFL who are identified as having an accessory pathway with ventricular preexcitation should undergo immediate cardioversion. (See "Wolff-Parkinson-White syndrome: Anatomy, epidemiology, clinical manifestations, and diagnosis", section on 'Atrial flutter'.)
For patients with minimal symptoms or signs attributable to AFL, conversion to sinus rhythm may be deferred in anticipation of either spontaneous conversion or radiofrequency catheter ablation. (See 'Radiofrequency catheter ablation' below.)
Among those patients who are not urgently cardioverted and who do not spontaneously revert to sinus rhythm, elective restoration of sinus rhythm is favored to decrease the risk of tachycardia-mediated cardiomyopathy. (See 'Rationale' above.) This is in contrast to AF, in which tolerance of permanent AF may be more likely chosen since rate control is usually possible. (See "Management of atrial fibrillation: Rhythm control versus rate control" and "Control of ventricular rate in atrial flutter", section on 'Summary and recommendations'.)
Circumstances in which it is reasonable to avoid cardioversion in patients with new-onset AFL include:
●Patients who are completely asymptomatic, particularly those who are elderly with multiple comorbidities or poor overall prognosis, where the risks of undergoing cardioversion and/or pharmacologic rhythm control may outweigh the benefits of restoring sinus rhythm.
●Patients who have a bleeding risk and cannot be anticoagulated during the peri-cardioversion and post-cardioversion periods.
METHOD OF CARDIOVERSION —
For most patients in whom a decision is made to restore sinus rhythm urgently, we prefer electrical to pharmacologic cardioversion. Radiofrequency catheter ablation is an option for stable patients who can wait until this procedure can be performed.
Electrical Cardioversion — Electrical cardioversion, also called direct current (DC) cardioversion, is a routine procedure in the management of patients with cardiac arrhythmias and is the preferred means for the immediate restoration of sinus rhythm. With appropriate patient selection and technique, DC cardioversion is rapid and safe. The success rate of 96 to 97 percent is higher than for any antiarrhythmic drug [1,2]. (See 'Pharmacologic cardioversion' below.)
Electrical cardioversion should be performed by physicians experienced in the procedure. The patient should be fasting to allow for safe use of sedation, serum electrolytes should be normal, and drug levels, such as digoxin, should be within the therapeutic range. Cardioversion techniques are discussed in detail separately. (See "Basic principles and technique of external electrical cardioversion and defibrillation".)
It is expected that normal sinus rhythm will resume once the AFL terminates. Sometimes, AF, ectopic atrial rhythm, or a significant bradycardia may result. The approach to each of these is discussed separately. (See "Atrial fibrillation: Overview and management of new-onset atrial fibrillation" and "Temporary cardiac pacing".)
Pharmacologic enhancement of direct current cardioversion — We use pharmacologic enhancement in selected patients. While the success of DC cardioversion is high for AFL, antiarrhythmic drugs may be initiated prior to electrical cardioversion to increase the likelihood of successful cardioversion and long-term maintenance of sinus rhythm [3]. (See "Atrial fibrillation: Cardioversion", section on 'Preprocedural antiarrhythmic drugs'.)
The decision to pretreat is often made by a physician experienced with the care of patients with one or more risk factors for cardioversion failure. (See "Atrial fibrillation: Cardioversion", section on 'Reasons not to perform cardioversion'.) The antiarrhythmic drug may restore sinus rhythm prior to DC cardioversion in some cases or may help prevent recurrent episodes of AFL early after cardioversion. In addition, for patients in whom long-term antiarrhythmic therapy will be used, early initiation (prior to DC cardioversion) may allow for an evaluation of tolerability of one or more drugs. For those patients in whom a decision has been made to attempt the long-term maintenance of sinus rhythm with antiarrhythmic drug therapy, it is reasonable to preferentially select a drug for cardioversion that can also be used for long-term maintenance. Based on these considerations, we use pharmacologic enhancement in selected patients, such as those in whom ablation will not be performed.
Pharmacologic cardioversion — A number of antiarrhythmic drugs may be used to terminate AFL and restore sinus rhythm. However, antiarrhythmic drugs are less effective than DC cardioversion and carry some degree of proarrhythmic risk. Thus, pharmacologic cardioversion is generally reserved for selected clinical scenarios. The most common reason for selecting pharmacologic cardioversion is that moderate or deep sedation is either unavailable or is expected to be poorly tolerated (for example, as in patients with hypotension).
General considerations — Most of the available data on the efficacy of antiarrhythmic drugs for the restoration of sinus rhythm are from patients with AF. The drugs that are effective in converting AF to sinus rhythm may also be effective in converting AFL. These include flecainide, dofetilide, propafenone, ibutilide, and amiodarone.
The primary drugs for rate control in patients with AFL are ibutilide and dofetilide, as these drugs have been better studied than the other drugs discussed below. (See "Atrial fibrillation: Cardioversion", section on 'Pharmacologic cardioversion'.)
●Ibutilide – Ibutilide, approved by the US Food and Drug Administration for intravenous (IV) use, converts AFL to sinus rhythm in approximately 60 percent of patients (compared with a 0 to 2 percent response to placebo) with a mean time to conversion of 30 minutes [4-6]. Ibutilide is more effective than procainamide for reversion of AFL (64 to 76 versus 0 to 14 percent) [7,8], and is also more effective than sotalol (70 versus 19 percent) (figure 1) [9] and amiodarone (87 versus 29 percent) [10]. (See "Therapeutic use of ibutilide".)
The most serious concern with ibutilide is QT interval prolongation that can lead to torsades de pointes [4-6]. The potential for torsades de pointes is increased in patients with severe HF or those who are being treated with another drug that prolongs the QT interval. On the other hand, the risk of proarrhythmia does not appear to be increased when ibutilide is given with amiodarone [11].
Because of the risk of torsades de pointes, patients treated with ibutilide should be observed with continuous electrocardiogram (ECG) monitoring for at least four hours after the infusion. (See "Therapeutic use of ibutilide", section on 'Proarrhythmia'.) The addition of IV magnesium, in doses of 4 to 10 grams, can enhance the cardioverting effect of ibutilide and may reduce the risk of torsades de pointes as well [12,13].
●Dofetilide – Oral dofetilide is effective for conversion of AFL and the conversion rate appears to be higher than in AF. As an example, the SAFIRE-D study randomly assigned 325 patients with AF (n = 277) or AFL (n = 48) to 125, 250, and 500 mcg of dofetilide twice daily [14]. At a dose of 500 mcg, the conversion rates for AF and AFL were 22 and 67 percent, respectively, compared with 1.2 percent for placebo. Conversion to sinus rhythm occurred in 70 percent within 24 hours, while 91 percent converted within 36 hours.
Dofetilide has the disadvantage of requiring the patient to be hospitalized for the first six doses, as it can cause torsade de pointes and sudden death [15,16].
IV dofetilide, which is not available in the United States, also appears to be effective for conversion of AFL. In one study of 16 patients, 54 percent reverted to sinus rhythm after dofetilide administration while in another series of 17 patients the rate of reversion was 64 percent, compared with 0 percent for placebo [17,18]. IV dofetilide is more effective than IV amiodarone. In a randomized trial that included 31 patients with AFL, the reversion rate with dofetilide was 75 percent versus 0 and 10 percent for amiodarone and placebo, respectively [19].
The following drugs are less commonly used or not recommended in this setting:
●Amiodarone – IV amiodarone is sometimes used for AFL conversion, but data are limited. A small study of nine patients with AFL demonstrated no patients converting with IV amiodarone [19]. Another study of 21 patients showed a success rate of 29 percent with IV amiodarone compared with 87 percent for ibutilide [10].
●Class IA antiarrhythmic drugs – The class IA antiarrhythmic drugs (quinidine, procainamide, and disopyramide) slow the rate of contraction of the atria but also may have a significant vagolytic effect which increases AV nodal conduction. These combined actions can result in 1:1 conduction at very rapid ventricular rates (waveform 1). For this reason, we do not recommend their use unless patients are pretreated with a drug(s) that blocks AV nodal conduction such as beta or calcium channel blockers.
●Class IC antiarrhythmic drugs – The class IC antiarrhythmic drugs propafenone and flecainide are less efficacious than other agents. Although they do not accelerate AV conduction, they can slow the AFL rate, often to a greater extent than the class IA drugs. Slowing of the AFL rate alone (eg, to 200 or 250 beats/min) can lead to 1:1 AV conduction. We do not recommend their use unless patients are pretreated with a drug(s) that blocks AV nodal conduction such as beta or calcium channel blockers.
●Rate control drugs – Digoxin, nondihydropyridine calcium channel blockers [20-22], and beta blockers can all be effective in the control of the ventricular rate during AFL. Although the hemodynamic improvement associated with a normalized ventricular rate may indirectly facilitate reversion to sinus rhythm, these drugs should be considered for the purpose of rate control, not for restoring sinus rhythm. (See "Control of ventricular rate in atrial flutter".)
●Vernakalant – IV vernakalant is approved by the European Commission for the rapid conversion of recent-onset AF (≤7 days duration for patients not undergoing surgery and ≤3 days duration for postcardiac surgery patients) to sinus rhythm. Based on one study in which the drug converted only 1 of 14 patients with AFL, we do not recommend its use [23]. (See "Cardiac excitability, mechanisms of arrhythmia, and action of antiarrhythmic drugs", section on 'Class III'.)
Ventricular preexcitation — In the setting of ventricular preexcitation, patients with AFL and rapid ventricular rates should be treated with IV ibutilide or procainamide, as is recommended in the treatment of AF with ventricular preexcitation [24]. Administration of IV adenosine, beta blockers, digoxin (oral or IV), nondihydropyridine calcium channel antagonists (oral or IV), or amiodarone (table 1) in patients with Wolff-Parkinson-White syndrome and preexcited AF and/or AFL is potentially harmful because these drugs accelerate the ventricular rate [24]. (See "Treatment of arrhythmias associated with the Wolff-Parkinson-White syndrome".)
Radiofrequency catheter ablation — Radiofrequency catheter ablation (RFA) can be performed while a stable patient is in AFL. In this setting, sinus rhythm is restored during the procedure. The use of RFA to interrupt the reentrant circuit supporting AFL in order to permanently maintain normal sinus rhythm is discussed elsewhere [25,26]. (See "Atrial flutter: Maintenance of sinus rhythm".)
Atrial overdrive pacing — Atrial overdrive pacing may be used for cardioversion in selected patients with flutter, though it is rarely performed because of the high success rate of direct current cardioversion and/or ablation.
In AFL, if the atrium is paced approximately 10 percent faster than the AFL rate for 15 to 30 seconds, the rate of the tachycardia increases to match that of the faster pacing rate; that is, it is entrained [27-29].
When the pacing is discontinued, one of several results may ensue:
●The original AFL may return.
●The AFL may cease with restoration of normal sinus rhythm (waveform 2).
●The patient may convert to AF.
●The AFL may change, possibly at a faster rate [30].
Atrial pacing can be useful in selected patients, including the following [27-29,31-33]:
●After cardiac surgery, since atrial pacing wires are often left in place during the early postoperative period.
●In patients with a pacemaker or implantable cardioverter-defibrillator where rapid pacing may be available through the device.
Very rarely, a temporary pacemaker may be used:
●In patients who have recurrent AFL due to an acute stress such as a myocardial infarction or respiratory failure; this represents a setting in which one would like to avoid repeated DC shocks and a temporary transvenous pacemaker can be used.
●In patients who have digitalis toxicity, a condition in which DC cardioversion may be particularly dangerous.
●In patients in whom anesthesia is a risk and pharmacologic cardioversion is not desired or unavailable [27-29,34,35].
The success rate of rapid atrial pacing may be increased by the concurrent IV administration of procainamide or ibutilide [36-38].
ANTICOAGULATION —
Anticoagulation leading to, at the time of, and after cardioversion of AFL is managed in a manner similar to that for AF. (See "Prevention of embolization prior to and after restoration of sinus rhythm in atrial fibrillation".)
The frequency of thromboembolism and the importance of anticoagulation were illustrated in a report of 100 patients who were referred to an electrophysiology laboratory for cardioversion of AFL that was present for at least six months: Six patients had a thromboembolic event that was attributable to AFL [39]. The event occurred during AFL or after cardioversion and none of the patients were receiving adequate anticoagulation. There were no embolic events in patients on adequate anticoagulation. One problem with interpreting these data is that many patients with chronic AFL also have periods of AF.
MAINTENANCE OF SINUS RHYTHM —
After conversion to sinus rhythm, an attempt should be made to address all correctable causes of AFL (eg, thyrotoxicosis or obesity). (See "Atrial flutter: Overview of diagnosis and management", section on 'Associated conditions'.)
In addition to radiofrequency catheter ablation (see 'Radiofrequency catheter ablation' above), pharmacologic therapy can be used to maintain sinus rhythm. This issue is discussed in detail separately. (See "Atrial flutter: Maintenance of sinus rhythm", section on 'Pharmacologic therapy'.)
SOCIETY GUIDELINE LINKS —
Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Atrial fibrillation" and "Society guideline links: Arrhythmias in adults".)
INFORMATION FOR PATIENTS —
UpToDate offers two types of patient education materials, “The Basics” and “Beyond the Basics.” The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.
Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on “patient info” and the keyword(s) of interest.)
●Basics topics (see "Patient education: Atrial flutter (The Basics)")
SUMMARY AND RECOMMENDATIONS
●Hemodynamically unstable patient – For atrial flutter (AFL) patients who have a rapid ventricular rate and evidence of hemodynamic instability or severe symptoms including myocardial ischemia, hypotension, angina, heart failure (HF), or evidence of ventricular preexcitation, we recommend urgent electrical cardioversion rather than any other approach (Grade 1A). (See 'Indications' above and 'Electrical Cardioversion' above.)
●Stable patient – For stable patients with AFL, we suggest elective electrical cardioversion rather than pharmacologic cardioversion or atrial pacing in patients without atrial leads (Grade 2A).
Patients who may reasonably prefer other approaches such as an attempt at pharmacologic conversion (or at rate control) include those who prefer not to undergo electrical cardioversion or those for whom moderate or deep sedation will be poorly tolerated or not available. Radiofrequency catheter ablation, if performed in a timely manner, is a reasonable alternative to electrical cardioversion. (See 'Indications' above and 'Electrical Cardioversion' above.)
Available data do not support the recommendation of a specific antiarrhythmic drug if pharmacologic conversion will be attempted. Options include ibutilide, amiodarone, flecainide, propafenone, or dofetilide.
We prefer ibutilide in situations where we desire acute pharmacologic cardioversion of AFL. (See 'Pharmacologic cardioversion' above.)
●Indications for overdrive pacing – For patients with atrial pacing wires in place (either as part of a permanent pacemaker, implantable-cardioverter defibrillator, or temporary pacing wires after cardiac surgery), we suggest rapid atrial pacing rather than electrical cardioversion (Grade 2C). (See 'Atrial overdrive pacing' above.)
As rapid atrial pacing can cause AFL to degenerate into atrial fibrillation (AF), the physician should be prepared for the management of AF.
●Method of rhythm control – Measures to maintain sinus rhythm include radiofrequency catheter ablation and pharmacologic therapy. (See "Atrial flutter: Maintenance of sinus rhythm", section on 'RF catheter ablation' and "Atrial flutter: Maintenance of sinus rhythm", section on 'Pharmacologic therapy'.)
