According to the American Heart Association guidelines, what are the recommendations for electrical or pharmacologic cardioversion of atrial fibrillation or atrial flutter, including anticoagulation requirements based on symptom duration, use of trans‑esophageal echocardiography, shock energy settings, sedation, contraindications, and post‑procedure monitoring and anticoagulation?

AHA Guidelines for Cardioversion of Atrial Fibrillation and Atrial Flutter

Anticoagulation Based on AF Duration

For AF lasting >48 hours or unknown duration, anticoagulate for at least 3-4 weeks before and 4 weeks after cardioversion (INR 2-3 for warfarin, or therapeutic NOAC dosing), regardless of whether electrical or pharmacological cardioversion is used. 1

AF Duration >48 Hours or Unknown Duration

• Conventional approach: Therapeutic anticoagulation for 3-4 weeks pre-cardioversion and 4 weeks post-cardioversion is the standard strategy 1
• TEE-guided alternative: If you cannot wait 3 weeks, perform TEE to exclude left atrial/left atrial appendage thrombus 1
  • If no thrombus identified: Initiate IV heparin bolus immediately before cardioversion, then continue oral anticoagulation (INR 2-3) for at least 4 weeks post-procedure 1
  • If thrombus identified: Defer cardioversion and anticoagulate for 3-4 weeks, then repeat TEE before attempting cardioversion 1
• NOACs (apixaban, rivaroxaban, etc.) are effective and safe alternatives to warfarin and should not be held before cardioversion 1, 2

AF Duration <48 Hours

• High thromboembolic risk (CHA₂DS₂-VASc ≥2 in men or ≥3 in women): Administer anticoagulation before cardioversion and continue afterward based on stroke risk 2
• Low thromboembolic risk (CHA₂DS₂-VASc 0 in men or 1 in women): Anticoagulation may be considered before cardioversion without mandatory post-cardioversion oral anticoagulation 2
• Despite the <48 hour window, LA thrombus and systemic embolism have been documented even in short-duration AF 1

Atrial Flutter

• Apply the same anticoagulation strategy as atrial fibrillation 1
• Stroke and systemic embolism at cardioversion have been reported frequently despite the perceived lower risk in chronic atrial flutter 1

Hemodynamically Unstable Patients

Perform immediate cardioversion without delaying for therapeutic anticoagulation when AF causes angina, MI, shock, or pulmonary edema. 1

• Initiate IV heparin or low-molecular-weight heparin immediately before or concurrent with cardioversion 1
• Continue oral anticoagulation (INR 2-3) for at least 4 weeks after cardioversion 1
• Emergency intervention should not be delayed to achieve therapeutic anticoagulation 2

Electrical Cardioversion Technique

Cardioversion is the recommended method to restore sinus rhythm in patients pursuing a rhythm-control strategy. 1

• If initial cardioversion unsuccessful, repeated attempts may be made after: 1
  • Adjusting electrode location
  • Applying pressure over electrodes
  • Administering antiarrhythmic medication
• Cardioversion is mandatory when rapid ventricular response causes ongoing myocardial ischemia, hypotension, or heart failure unresponsive to pharmacological therapy 1
• For AF with pre-excitation (WPW), cardioversion is required when tachycardia causes hemodynamic instability 1

Post-Cardioversion Anticoagulation Duration

Continue anticoagulation for at least 4 weeks after cardioversion in all patients, regardless of baseline stroke risk, due to atrial stunning. 2

• 98% of thromboembolic events occur within 10 days post-cardioversion, with the majority in the first 3 days 1, 2
• Atrial mechanical dysfunction ("stunning") persists for weeks despite return to sinus rhythm, creating a prothrombotic state 1, 2
• After the initial 4-week period, long-term anticoagulation decisions should be based on the patient's CHA₂DS₂-VASc score and bleeding risk, not on whether sinus rhythm was maintained 1, 2

Medications to Continue or Avoid

Continue During Cardioversion

• Beta-blockers (metoprolol, atenolol, etc.): Continue at current dose—they do not interfere with cardioversion and help maintain sinus rhythm afterward 3
• NOACs (apixaban, rivaroxaban): Do not hold before cardioversion 2

Contraindicated in Specific Situations

• Digoxin, non-dihydropyridine calcium channel blockers, or amiodarone: Do not use in AF with pre-excitation (WPW) 1
• Non-dihydropyridine calcium channel antagonists: Avoid in decompensated heart failure 1
• Dronedarone: Do not use for rate control in permanent AF 1

Critical Pitfalls to Avoid

• Never discontinue anticoagulation immediately after successful cardioversion—atrial stunning persists regardless of rhythm 2
• Never assume young age or low CHA₂DS₂-VASc score eliminates the 4-week post-cardioversion anticoagulation requirement—this applies to all patients 2
• Never delay emergency cardioversion to achieve therapeutic anticoagulation in hemodynamically unstable patients—start heparin and cardiovert immediately 1, 2
• Never assume atrial flutter carries no thromboembolism risk—use the same anticoagulation protocol as AF 1
• Do not perform AV nodal ablation without prior attempts at pharmacological rate control 1

Sedation and Monitoring

• Appropriate sedation is required for electrical cardioversion (specific agents not detailed in AHA guidelines but typically procedural sedation with propofol or etomidate in monitored settings)
• Post-procedure monitoring should assess for rhythm stability and signs of thromboembolism 1