How to treat atrial flutter?

How to Break Atrial Flutter

Immediate synchronized electrical cardioversion is the definitive treatment for breaking atrial flutter, particularly in hemodynamically unstable patients, and requires lower energy levels than atrial fibrillation cardioversion. 1, 2

Hemodynamic Status Determines Initial Approach

Unstable Patients (Hypotension, Acute Heart Failure, Ongoing Chest Pain, Altered Mental Status)

• Proceed directly to synchronized electrical cardioversion without delay 1, 2
• Atrial flutter cardioverts successfully at lower energy levels compared to atrial fibrillation (typically 50-100 joules initially) 1, 3
• Do not waste time with pharmacological attempts in unstable patients 1

Stable Patients: Choose Between Rate Control or Rhythm Control

Rate Control Strategy (Temporizing measure)

First-line agents for acute rate control: 1, 2

• Intravenous diltiazem is the preferred calcium channel blocker due to superior safety and efficacy profile 1, 3

  • Dose: 0.25 mg/kg IV bolus over 2 minutes, then 5-15 mg/h infusion 1

• Esmolol is the preferred beta-blocker for acute situations due to rapid onset 1, 3

  • Dose: 500 mcg/kg IV bolus over 1 minute, then 50-300 mcg/kg/min infusion 1

• Alternative beta-blockers: metoprolol 2.5-5.0 mg IV bolus over 2 minutes, up to 3 doses 1

Critical caveat: Rate control is significantly more difficult in atrial flutter than atrial fibrillation due to less concealed AV nodal conduction 1, 3, 4

Absolute contraindications to calcium channel blockers and beta-blockers: 1, 3

• Advanced heart failure (decompensated)
• Heart block or sinus node dysfunction without pacemaker
• Pre-excitation syndromes (Wolff-Parkinson-White) - these agents can facilitate antegrade conduction along accessory pathways, potentially causing ventricular fibrillation 2, 4

For systolic heart failure when beta-blockers contraindicated:

• Intravenous amiodarone: 300 mg IV over 1 hour, then 10-50 mg/h over 24 hours 1, 2, 4

Rhythm Control Strategy (Definitive approach)

Elective synchronized electrical cardioversion is the most effective method: 1, 2, 3

• Success rate exceeds 90% 1
• Restores sinus rhythm immediately 5
• Prevents tachycardia-mediated cardiomyopathy 1

Pharmacological cardioversion options (less effective than electrical, but avoids sedation): 1

1. Intravenous ibutilide - most effective pharmacological agent 1, 6

   • Converts approximately 60% of atrial flutter cases 1
   • More effective for flutter than fibrillation (≥48% vs ≤40%) 6
   • Major risk: Torsades de pointes - occurs in 1.7% of patients 6
   • Requires continuous ECG monitoring for at least 4 hours after completion 1, 6
   • Pretreatment with magnesium increases efficacy and reduces torsades risk 1
   • Contraindicated if QTc >440 msec or serum potassium <4 mEq/L 6

2. Oral dofetilide - alternative Class III agent 1

   • Similar efficacy to ibutilide but oral administration
   • Also carries torsades risk requiring monitoring 1

3. IV procainamide - infrequently effective (only 27% conversion rate in recent trial) 7

Rapid atrial pacing - specialized technique when pacing wires already in place: 1

• Effective in >50% of cases 1
• Particularly useful post-cardiac surgery or with permanent pacemaker/ICD 1
• Pace at 5-10% above flutter rate for ≥15 seconds, incrementally increasing until conversion or atrial fibrillation occurs 1
• May precipitate atrial fibrillation, which is often easier to rate-control 1

Anticoagulation Requirements (Critical - Same as Atrial Fibrillation)

Duration >48 hours or unknown: 1, 2, 3

• Therapeutic anticoagulation for 3 weeks BEFORE cardioversion
• Continue for 4 weeks AFTER cardioversion
• Stroke risk in atrial flutter is 3% annually, equivalent to atrial fibrillation 2, 3

Duration <48 hours and low thromboembolic risk: 1

• Initiate anticoagulation (IV heparin, LMWH, or factor Xa/direct thrombin inhibitor) immediately before or after cardioversion
• Continue based on long-term stroke risk profile

Long-Term Definitive Management

Catheter ablation of the cavotricuspid isthmus (CTI) should be strongly considered as first-line therapy: 2, 3, 4

• Success rate exceeds 90% with low complication rates 4
• Class I indication for symptomatic atrial flutter or flutter refractory to pharmacological rate control 2, 4
• Prevents recurrence more effectively than antiarrhythmic drugs (which control only 50-60% of patients) 8

Important consideration: 22-50% of patients develop atrial fibrillation within 14-30 months after CTI ablation 2, 3, 4

Common Pitfalls to Avoid

1. Never use AV nodal blocking agents (diltiazem, verapamil, beta-blockers, digoxin) in patients with pre-excitation - can precipitate ventricular fibrillation 2, 4

2. Do not underestimate anticoagulation requirements - atrial flutter carries the same stroke risk as atrial fibrillation 2, 3

3. Correct hypokalemia and hypomagnesemia before ibutilide administration to reduce torsades risk 1, 6

4. Recognize that rate control is more difficult in flutter than fibrillation - have low threshold for cardioversion 1, 3, 4

5. Monitor for at least 4 hours after ibutilide (longer if any arrhythmic activity noted) 1, 6