p.36 抽出テキスト

are more common in patients with longer-duration persistent AF or more dilated left atria or when linear ablation lesions are used.333–338 Non–reentrant focal arrhythmias often originate at lesion edges or reconnected segments of prior isolated pulmonary veins.333 Reisolation of the pulmonary vein and ablation of any nonpulmonary vein foci are often effective in treating these arrhythmias. Detailed activation and entrainment mapping of the tachycardia during a second procedure result in effective ablation in approximately 90% of patients.335 Although right atrial CTI-dependent flutter may also occur, most of the tachycardias originate in the left atrium. As with all types of atrial flutter, it may be very difficult to achieve rate control in patients with post–AF ablation non–CTI-dependent flutter (far more so than in patients with preablation AF). When the ventricular response cannot be controlled with common rate-control medications, attempts at restoration of sinus rhythm with pharmacological therapy and cardioversion are often required. Many of the atrial flutters that are observed during the first 3 months after catheter ablation or after cardiac surgery will not recur later on. For this reason, it is advised that attempts at ablation of atrial flutter after AF ablation be deferred until after the 3-month waiting period.339 Rarely, pharmacological therapy and attempts at rhythm control with antiarrhythmic drug therapy fail to adequately control atrial flutter during the 3 months after AF ablation. In this situation, early repeat ablation is warranted.

7.3 Acute Treatment: Recommendations

Recommendations for Acute Treatment of Atrial Flutter COR LOE Recommendations

I A 1.  Oral dofetilide or intravenous ibutilide is useful for acute pharmacological cardioversion in patients with atrial flutter.119,340–346

See Online Data Supplements 16 and 17. Pharmacological cardioversion of atrial flutter is generally less effective than synchronized cardioversion and carries the potential risk of proarrhythmia but can be an option when sedation is not available or not well tolerated or when indicated by patient preference. Intravenous ibutilide converts atrial flutter to sinus rhythm in approximately 60% of cases.342 The major risk is torsades de pointes, which is more likely to occur in patients with reduced left ventricular ejection fraction. Patients receiving ibutilide should undergo continuous ECG monitoring during administration and for at least 4 hours after completion of dosing. Pretreatment with magnesium can increase the efficacy and reduce the risk of torsades de pointes.119 Anticoagulation issues for chemical cardioversion are the same as those for electrical cardioversion of atrial flutter.10

I B-R 2.  Intravenous or oral beta blockers, diltiazem, or verapamil are useful for acute rate control in patients with atrial flutter who are hemodynamically stable.347–354

See Online Data Supplements 16 and 17. It is often more difficult to achieve rate control for atrial flutter than for AF. Nonetheless, effective rate control may be achieved with beta blockers, diltiazem, or verapamil in patients with atrial flutter through a direct effect on the AV node. Hypotension is the main adverse effect. Intravenous diltiazem is the preferred intravenous calcium channel blocker for acute rate control because of its safety and efficacy.351 Diltiazem and verapamil should be avoided in patients with advanced heart failure and in patients with heart block or sinus node dysfunction in the absence of pacemaker therapy. Verapamil and diltiazem also should not be used in patients with known preexcitation. The heart rate control achieved with beta blockers is similar to that seen with verapamil and diltiazem. The rate-slowing effect of beta blockers is largely related to reduction of sympathetic tone. Esmolol is generally the preferred intravenous beta blocker because of its rapid onset.353 Care should be used in administering beta blockers for rate control in atrial flutter patients with decompensated heart failure or reactive airway disease.355

I B-NR 3.  Elective synchronized cardioversion is indicated in stable patients with well-tolerated atrial flutter when a rhythm-control strategy is being pursued.356–358

See Online Data Supplements 16 and 17. Heart rates can be difficult to control in atrial flutter. Cardioversion for atrial flutter can be successful at lower energy levels than for AF.356 Anticoagulation issues for cardioversion are the same as those for patients with AF and are addressed in the 2014 AF guideline.10 Restoration of sinus rhythm is favored to avoid development of tachycardia-mediated cardiomyopathy, which is associated with a rapid ventricular response in atrial flutter.

I B-NR 4.  Synchronized cardioversion is recommended for acute treatment of patients with atrial flutter who are hemodynamically unstable and do not respond to pharmacological therapies.75,208,356,359 See Online Data Supplements 16 and 17. The ventricular rate in atrial flutter can be difficult to control with pharmacological therapy. In patients with any signs or symptoms of hemodynamic compromise attributed to atrial flutter, synchronized cardioversion (with appropriate considerations with regard to anticoagulation) should be pursued without delay.

I C-LD 5.  Rapid atrial pacing is useful for acute conversion of atrial flutter in patients who have pacing wires in place as part of a permanent pacemaker or implantable cardioverter-defibrillator or for temporary atrial pacing after cardiac surgery.360–364

See Online Data Supplements 16 and 17. Atrial pacing is effective at terminating flutter in >50% of cases.364 Atrial pacing is more commonly applied in situations in which atrial wires are already in place, such as in the postoperative setting or in patients with programmable cardiac implanted electrical devices. A temporary pacing wire may also be placed and atrial pacing for termination of atrial flutter can be useful when sedation is contraindicated, or in the setting of digitalis toxicity, in which DC cardioversion is contraindicated. Pace-termination is performed by pacing the atrium at a rate starting approximately 5% to 10% above the atrial flutter rate to achieve atrial entrainment and by maintaining pacing for ≥15 seconds, with repeated attempts at incrementally faster rates (reducing the pacing cycle length by 5 to 10 ms until normal sinus rhythm or AF occurs.364 When AF is precipitated, this is often more easily rate-controlled and may subsequently revert to sinus rhythm. Recommendations for anticoagulation with regard to pace-termination of atrial flutter are the same as those for chemical or electrical conversion of AF.

Downloaded from http://ahajournals.org by on October 7, 2026