What is the recommended treatment for atrial flutter using cardioversion?

Management of Atrial Flutter with Cardioversion

Synchronized electrical cardioversion is the most effective treatment for atrial flutter and is indicated as first-line therapy in hemodynamically unstable patients and in stable patients when pursuing a rhythm-control strategy. 1

Initial Assessment and Approach

When managing atrial flutter with cardioversion, consider:

• Hemodynamic stability
• Duration of arrhythmia
• Anticoagulation status
• Prior attempts at rhythm control

Cardioversion Protocol

Hemodynamically Unstable Patients

• Immediate synchronized electrical cardioversion without delay 1
• Initial energy: 100J (more effective than 50J) 2
• No need to wait for anticoagulation if unstable 3

Hemodynamically Stable Patients

• Elective synchronized electrical cardioversion is indicated when pursuing rhythm control 1
• Initial energy: 100J (provides higher first-shock success rate of 85% vs. 70% with 50J) 2
• If unsuccessful, repeat attempts may be made after:
  • Adjusting electrode position
  • Applying pressure over electrodes
  • Administering antiarrhythmic medication 1

Anticoagulation Requirements

• For atrial flutter ≥48 hours or unknown duration:

  • Anticoagulate with warfarin (INR 2-3) for at least 3 weeks before and 4 weeks after cardioversion 1
  • Alternatively, use direct oral anticoagulants (DOACs) for ≥3 weeks before and 4 weeks after cardioversion 1
  • If immediate cardioversion needed, start anticoagulation as soon as possible and continue for at least 4 weeks 1

• For atrial flutter <48 hours:

  • With high stroke risk: IV heparin, LMWH, or direct thrombin/factor Xa inhibitor before or immediately after cardioversion 1
  • With low stroke risk: IV heparin, LMWH, DOAC, or no antithrombotic may be considered 1

• TEE-guided approach:

  • If ≥48 hours duration without 3 weeks prior anticoagulation, TEE can be performed to exclude left atrial thrombus 1
  • Anticoagulation must be initiated before TEE and maintained for at least 4 weeks after cardioversion 1

Caution: A normal TEE does not completely eliminate thromboembolic risk in atrial flutter 4

Pharmacological Options

Pharmacological Cardioversion

• First-line agents (Class I recommendation):

  • Oral dofetilide
  • IV ibutilide (particularly effective for atrial flutter) 1
  • Flecainide or propafenone (if no structural heart disease) 1

• Second-line agent (Class IIa recommendation):

  • Amiodarone 1

Rate Control Prior to Cardioversion

For hemodynamically stable patients requiring rate control:

• First-line: IV or oral beta blockers, diltiazem, or verapamil 1
• For patients with heart failure: IV amiodarone when beta blockers are contraindicated or ineffective 1

Alternative Approaches

• Rapid atrial pacing: Useful for acute conversion in patients with existing pacing wires (e.g., post-cardiac surgery, permanent pacemaker) 1
• Catheter ablation: Highly effective for long-term management of recurrent atrial flutter 1
  • Consider as definitive treatment for patients with recurrent atrial flutter
  • Particularly useful for cavotricuspid isthmus (CTI)-dependent flutter

Follow-up and Long-term Management

• Assess for maintenance of sinus rhythm 2-4 weeks after cardioversion 3
• Long-term anticoagulation should be based on thromboembolic risk profile 1
• Consider catheter ablation for recurrent atrial flutter, especially if symptomatic or refractory to pharmacological rate control 1

Important Caveats

• Atrial flutter and atrial fibrillation often coexist; 22-50% of patients develop AF within 14-30 months after CTI ablation for flutter 1
• Risk factors for developing AF after flutter ablation include prior AF, depressed LV function, structural heart disease, and increased LA size 1
• Cardioversion of atrial flutter typically requires lower energy than for atrial fibrillation 1
• Avoid non-dihydropyridine calcium channel blockers and digoxin in patients with pre-excitation 1