What are the indications for cardioversion of atrial fibrillation (AFib)?

From the Guidelines

Cardioversion is indicated for atrial fibrillation (AFib) in symptomatic patients with persistent AF as part of a rhythm control approach, and should be considered within 12 months of diagnosis in selected patients with AF at risk of thromboembolic events to reduce the risk of cardiovascular death or hospitalization. When considering cardioversion, it's crucial to assess the patient's eligibility for anticoagulation, as direct oral anticoagulants are recommended in preference to vitamin K antagonists (VKAs) in eligible patients with AF undergoing cardioversion for thromboembolic risk reduction 1. The decision to proceed with cardioversion should also take into account the duration of AFib, with a wait-and-see approach for spontaneous conversion to sinus rhythm within 48 hours of AF onset considered in patients without hemodynamic compromise as an alternative to immediate cardioversion 1. Key considerations for cardioversion include:

• The use of anticoagulation for at least 3 weeks prior to the procedure, or a transesophageal echocardiogram to rule out left atrial thrombus, in patients with AFib lasting longer than 48 hours or of unknown duration 1
• The continuation of anticoagulation for at least 4 weeks after cardioversion, regardless of the patient's CHA₂DS₂-VASc score, due to the risk of thromboembolism during recovery of atrial mechanical function 1
• The selection of appropriate medications for pharmacological cardioversion, such as amiodarone, flecainide, or propafenone, based on the presence of structural heart disease
• The use of electrical cardioversion with a biphasic defibrillator under procedural sedation, typically with 120-200 joules. It's essential to weigh the benefits and risks of cardioversion in each patient, considering factors such as the duration of AFib, left atrial size, and presence of structural heart disease, to determine the most effective treatment strategy 1.

From the FDA Drug Label

Ibutilide fumarate injection is indicated for the rapid conversion of atrial fibrillation or atrial flutter of recent onset to sinus rhythm. Patients with atrial arrhythmias of longer duration are less likely to respond to ibutilide fumarate. The effectiveness of ibutilide has not been determined in patients with arrhythmias of more than 90 days in duration The main indications for cardioversion of atrial fibrillation (afib) using ibutilide are:

• Recent onset of afib
• Duration of afib less than 90 days It is essential to note that patients with atrial fibrillation of more than 2 to 3 days’ duration must be adequately anticoagulated, generally for at least 2 weeks, before cardioversion can be considered. The decision to use ibutilide for cardioversion should be made on a case-by-case basis, taking into account the potential benefits and risks of the treatment, as well as the presence of any underlying cardiovascular conditions 2.

From the Research

Indications for Cardioversion in Atrial Fibrillation

The decision to perform cardioversion in patients with atrial fibrillation (AF) depends on several factors, including the duration of AF, the presence of symptoms, and the risk of thromboembolic complications.

• The success rate of cardioversion is highest (≈95%) when performed within 12-48 hours after the onset of arrhythmic symptoms, compared to a lower success rate of ≈85% in later elective cardioversions 3.
• Early cardioversion is also associated with a lower risk of early AF recurrences compared to later elective cardioversions 3.
• However, cardioversion increases the risk of thromboembolic complications, which can be reduced with effective anticoagulation 3, 4.
• The use of antiarrhythmic drugs, such as flecainide, can be effective in pharmacologically cardioverting AF, especially in patients with recent-onset AF (<24 hours) 5.
• The choice of anticoagulant, such as apixaban or warfarin, is also important in reducing the risk of thromboembolic events after cardioversion 6.

Patient Selection for Cardioversion

The selection of patients for cardioversion depends on several factors, including:

• The presence of symptoms, such as palpitations, shortness of breath, or chest pain 5.
• The duration of AF, with earlier cardioversion associated with a higher success rate 3.
• The risk of thromboembolic complications, which can be reduced with effective anticoagulation 3, 4.
• The presence of underlying heart disease, such as structural or coronary artery disease, which may affect the choice of antiarrhythmic drugs or anticoagulants 5.

Timing of Cardioversion

The timing of cardioversion is an important factor in optimizing the safety and efficacy of the procedure.

• Early cardioversion (within 12-48 hours after the onset of arrhythmic symptoms) is associated with a higher success rate and a lower risk of early AF recurrences 3.
• Delayed cardioversion (after 48 hours) may be associated with a lower success rate and a higher risk of thromboembolic complications 3, 4.
• The use of transoesophageal echocardiography may be useful in clinical scenarios where early cardioversion is desirable due to debilitating clinical symptoms and a short duration of arrhythmia or uncertain adequacy of preceding anticoagulation 4.