Treatment for Atrial Flutter
The most effective treatment for atrial flutter is catheter ablation of the cavotricuspid isthmus (CTI), which has success rates exceeding 90% and should be considered first-line therapy for patients with symptomatic atrial flutter or flutter refractory to pharmacological rate control. 1, 2
Initial Management Based on Hemodynamic Status
Hemodynamically Unstable Patients
- Immediate synchronized cardioversion is recommended for patients with atrial flutter who are hemodynamically unstable 1, 3
- Cardioversion for atrial flutter can be successful at lower energy levels than for atrial fibrillation 1, 2
- Appropriate anticoagulation considerations should be addressed prior to cardioversion when possible 3, 4
Hemodynamically Stable Patients
- Treatment strategy can focus on either rate control or rhythm control 1, 3
- For rate control: intravenous or oral beta blockers, diltiazem, or verapamil are first-line agents 1, 5
- For rhythm control: oral dofetilide or intravenous ibutilide for pharmacological cardioversion, or elective synchronized cardioversion 1, 2
Rate Control Strategy
- Intravenous diltiazem is the preferred calcium channel blocker due to its safety and efficacy profile 1, 3
- Esmolol is generally the preferred intravenous beta blocker for acute rate control because of its rapid onset 5
- Target heart rate should be <100 beats per minute at rest 6
- Important medication considerations:
- Avoid diltiazem and verapamil in patients with advanced heart failure, heart block, or sinus node dysfunction without pacemaker therapy 5, 7
- Avoid calcium channel blockers and beta blockers in patients with pre-excitation due to risk of accelerated ventricular rates 5, 7
- For patients with systolic heart failure where beta blockers are contraindicated or ineffective, intravenous amiodarone can be useful 3, 5
Rhythm Control Strategy
Acute Conversion Options
- Elective synchronized cardioversion is indicated in stable patients when pursuing rhythm control 1, 3
- Pharmacological cardioversion options:
- Rapid atrial pacing is useful for acute conversion in patients with pacing wires already in place (e.g., permanent pacemaker, ICD, temporary wires after cardiac surgery) 1, 3
Long-Term Rhythm Control
- Catheter ablation of the CTI is the most effective long-term rhythm control strategy 1, 2
- For patients not suitable for ablation, antiarrhythmic drugs can be used:
Anticoagulation Considerations
- Antithrombotic therapy in patients with atrial flutter should follow the same protocols as for atrial fibrillation 1, 3
- Risk of stroke in atrial flutter is significant, with reported rates of 3% annually 3, 5
- For cardioversion of atrial flutter lasting ≥48 hours or of unknown duration, anticoagulation is recommended for at least 3 weeks before and 4 weeks after cardioversion 2, 4
- Warfarin therapy with a target INR of 2.0-3.0 is recommended for patients with risk factors for stroke 4, 10
Important Clinical Considerations and Pitfalls
- Rate control can be more difficult to achieve in atrial flutter than in atrial fibrillation due to less concealed AV nodal conduction 1, 5
- Atrial flutter and atrial fibrillation frequently coexist—22-50% of patients develop atrial fibrillation within 14-30 months after CTI ablation 1, 5
- Risk factors for developing atrial fibrillation after atrial flutter ablation include prior atrial fibrillation, depressed left ventricular function, structural heart disease, and increased left atrial size 1, 5
- Using verapamil or diltiazem in patients with pre-excitation can precipitate ventricular fibrillation 3, 7
- Insufficient monitoring for QT prolongation when using ibutilide for pharmacological cardioversion can lead to torsades de pointes 3, 5