How do you cardiovert someone in atrial fibrillation (AFib)

From the Guidelines

To cardiovert someone in atrial fibrillation (AFib), electrical cardioversion is recommended in patients with acute or worsening haemodynamic instability to improve immediate patient outcomes, as stated in the 2024 ESC guidelines 1. For electrical cardioversion:

• Sedate the patient (e.g., with propofol or midazolam)
• Apply defibrillator pads
• Set the defibrillator to synchronized mode
• Deliver a shock of 120-200 joules biphasic (or 200 joules monophasic)
• Repeat with higher energy if needed Before cardioversion, ensure:
• Patient is anticoagulated with direct oral anticoagulants (DOACs) or vitamin K antagonists (VKAs) for at least 3 weeks, as recommended in the 2024 ESC guidelines 1
• No left atrial thrombus on transoesophageal echocardiogram, as recommended in the 2024 ESC guidelines 1
• Electrolytes are corrected
• Underlying causes of AFib are addressed It is also important to note that therapeutic oral anticoagulation should be continued for at least 4 weeks after cardioversion and long-term in patients with thromboembolic risk factor(s) irrespective of whether sinus rhythm is achieved, to prevent thromboembolism, as recommended in the 2024 ESC guidelines 1. The choice between electrical and pharmacological cardioversion depends on the patient's clinical status, duration of AFib, and underlying conditions, and early cardioversion is not recommended without appropriate anticoagulation or transoesophageal echocardiography if AF duration is longer than 24 h, or there is scope to wait for spontaneous cardioversion, as stated in the 2024 ESC guidelines 1.

From the FDA Drug Label

Proarrhythmic events must be anticipated Skilled personnel and proper equipment, including cardiac monitoring equipment, intracardiac pacing facilities, a cardioverter/defibrillator, and medication for treatment of sustained ventricular tachycardia, including polymorphic ventricular tachycardia, must be available during and after administration of ibutilide fumarate injection Management of polymorphic ventricular tachycardia includes discontinuation of ibutilide, correction of electrolyte abnormalities, especially potassium and magnesium, and overdrive cardiac pacing, electrical cardioversion, or defibrillation.

To cardiovert someone in atrial fibrillation (AFib), electrical cardioversion should be performed by skilled personnel with proper equipment, including a cardioverter/defibrillator. The patient should be continuously monitored with cardiac monitoring equipment.

• Correction of electrolyte abnormalities, especially potassium and magnesium, is necessary before cardioversion.
• Overdrive cardiac pacing may also be used to manage polymorphic ventricular tachycardia.
• Pharmacologic therapies, such as magnesium sulfate infusions, may be used in addition to cardioversion. 2

From the Research

Cardioversion Procedure

To cardiovert someone in atrial fibrillation (AFib), the following steps can be taken:

• Electrical cardioversion is often the treatment of first choice for restoring sinus rhythm in patients with AFib 3
• The procedure involves the use of external direct current cardioversion, which has proven to be safe and effective 4, 5
• Biphasic shock waveforms and anterior-posterior positioning of defibrillation electrodes have improved cardioversion efficacy 6, 5
• An initial energy of 200 J is recommended for biphasic defibrillators, and 300 to 360 J are recommended for monophasic defibrillators, with the electrodes placed in the anterior posterior position 5

Patient Selection and Preparation

• Patients with AFib of short duration (less than 48 hours) can undergo immediate cardioversion, except those with a high risk for thromboembolic events 3
• Patients with AFib of longer duration (more than 48 hours) require anticoagulation for at least three weeks or exclusion of atrial thrombus by transesophageal echocardiography before cardioversion 3, 5
• Antiarrhythmic drugs may enhance the results of cardioversion by helping overcome shock failure or by preventing immediate recurrence of AFib 3, 5

Technical Variables and Success Rate

• The success rate of cardioversion depends on various patient characteristics and technical variables, such as the use of biphasic instead of monophasic shocks 3
• Active compression applied to the anterior defibrillation electrode has been shown to be more effective for persistent AFib cardioversion than standard anterior-posterior cardioversion, with lower defibrillation threshold and higher success rate 6
• The use of dual defibrillators or internal cardioversion may be considered for refractory cases 5

Complications and Post-Cardioversion Care

• Thromboembolism is the most important complication associated with cardioversion, but it can be prevented by providing 3 weeks of anticoagulation before the procedure or by excluding the presence of thrombi by transesophageal echocardiography, followed by an additional 4 weeks of anticoagulation 3, 5
• Post-cardioversion anticoagulation is recommended, with the duration and indication depending on individual characteristics (CHADS(2) score) and the duration of the preceding episode of AFib 3