From the Guidelines
Cardioversion of atrial fibrillation should be considered in symptomatic patients with persistent AF as part of a rhythm control approach, with direct oral anticoagulants recommended in preference to VKAs in eligible patients undergoing cardioversion for thromboembolic risk reduction. The guidelines for cardioversion of atrial fibrillation emphasize the importance of anticoagulation management and appropriate patient selection.
Key Considerations
- For patients with atrial fibrillation lasting more than 48 hours or of unknown duration, anticoagulation should be given for at least 3 weeks before cardioversion and continued for at least 4 weeks after, as recommended by the 2024 ESC guidelines 1.
- Direct oral anticoagulants such as apixaban, rivaroxaban, dabigatran, or edoxaban are preferred over VKAs for thromboembolic risk reduction in eligible patients undergoing cardioversion 1.
- A transesophageal echocardiogram can be performed to rule out left atrial thrombus, allowing immediate cardioversion if negative, but still requiring post-procedure anticoagulation 1.
- For atrial fibrillation lasting less than 48 hours, cardioversion can proceed without prior anticoagulation, though post-procedure anticoagulation is recommended based on stroke risk factors 1.
Anticoagulation Management
- Therapeutic oral anticoagulation for at least 3 weeks before scheduled cardioversion and continued for at least 4 weeks after is recommended to prevent procedure-related thromboembolism 1.
- Oral anticoagulation should be continued long-term in patients with thromboembolic risk factors, irrespective of whether sinus rhythm is achieved 1.
Cardioversion Techniques
- Electrical cardioversion typically uses 120-200 joules biphasic energy (or 200-360 joules monophasic) 1.
- Pharmacological cardioversion may employ agents like amiodarone, flecainide, or propafenone, with specific dosing regimens and considerations for each medication 1.
Patient Selection and Preparation
- Patients should be selected for cardioversion based on symptoms, duration of atrial fibrillation, and thromboembolic risk factors 1.
- Patients should fast for 6-8 hours before electrical cardioversion, which requires procedural sedation 1.
From the FDA Drug Label
Patients had had their arrhythmias for 3 hours to 90 days, were anticoagulated for at least 2 weeks if atrial fibrillation was present more than 3 days, had serum potassium of at least 4.0 mEq/L and QTc below 440 msec, and were monitored by telemetry for at least 24 hours. Among patients with atrial flutter, 53% receiving 1 mg ibutilide fumarate and 70% receiving 2 mg ibutilide fumarate converted, compared to 18% of those receiving sotalol In patients with atrial fibrillation, 22% receiving 1 mg ibutilide fumarate and 43% receiving 2 mg ibutilide fumarate converted compared to 10% of patients receiving sotalol.
The guidelines for cardioversion of atrial fibrillation using ibutilide fumarate include:
- Anticoagulation: for at least 2 weeks if atrial fibrillation is present for more than 3 days
- Serum potassium: at least 4.0 mEq/L
- QTc interval: below 440 msec
- Monitoring: telemetry for at least 24 hours
- Dosing: 1 mg or 2 mg of ibutilide fumarate, with conversion rates of 22% and 43%, respectively, for atrial fibrillation 2
- Conversion rates: higher for patients with more recent onset of arrhythmia (less than 30 days) and for those with atrial flutter compared to atrial fibrillation
- Key considerations:
- Patients should be hemodynamically stable
- Patients with specific cardiovascular conditions such as symptomatic heart failure, recent acute myocardial infarction, and angina should be excluded
- Electrical cardioversion is allowed 90 minutes after the infusion is complete
- Other antiarrhythmic drugs can be given 4 hours postinfusion 2
From the Research
Guidelines for Cardioversion of Atrial Fibrillation
The guidelines for cardioversion of atrial fibrillation are as follows:
- Cardioversion should be reserved for patients who are symptomatic despite adequate rate control 3.
- For recent-onset atrial fibrillation (<24 h), pharmacological cardioversion using agents like flecainide can be highly successful, but caution should be exercised in patients with potential structural or coronary artery disease due to the risk of proarrhythmia 3.
- If there is doubt about the suitability of a patient for pharmacological cardioversion, DC cardioversion is the safer option 3.
- The use of antiarrhythmic drugs to maintain sinus rhythm is recommended due to the high recurrence rate of atrial fibrillation after cardioversion (71-84% at 1 year) 3.
Pharmacological Cardioversion
Pharmacological cardioversion using intravenous antiarrhythmic agents is commonly indicated in symptomatic patients with recent-onset atrial fibrillation 4.
- The main characteristics of selected intravenous antiarrhythmic agents for conversion of recent-onset AF, the reported success rates, and possible adverse events are discussed 4.
- Intravenous flecainide and propafenone are the only Class I agents still recommended by recent guidelines 4.
- New Class III agents like dofetilide and ibutilide have high and rapid efficacy in converting AF to sinus rhythm but require strict surveillance with electrocardiogram (ECG) monitoring during and after intravenous administration due to the potential risk of QT prolongation and Torsades de Pointes 4.
Rate Control vs Rhythm Control
Rate control is often better than rhythm control in patients with atrial fibrillation 5.
- Digoxin, betablockers, diltiazem, and verapamil slow the heart rate but rarely restore sinus rhythm 5.
- Amiodarone, disopyramide, flecainide, quinidine, and sotalol can be used to prevent relapse of atrial fibrillation after electrical cardioversion, but they all have potentially serious adverse effects 5.
- Rhythm control did not reduce the risk of death or serious cardiovascular events during a mean follow-up period of 3.5 years and caused more adverse events than rate control 5.
Emergency Management
In emergency situations, differentiating primary and secondary atrial fibrillation with rapid ventricular response and evaluating hemodynamic stability are vital components of assessment and management 6.