From the Guidelines
Electrical cardioversion is recommended in atrial fibrillation (AFib) patients with acute or worsening hemodynamic instability to improve immediate patient outcomes. The rationale for electrical cardioversion of AFib is to rapidly restore normal sinus rhythm when symptoms are severe or when rate control strategies are insufficient. This procedure involves delivering a synchronized electrical shock to the heart, which depolarizes cardiac tissue and allows the sinoatrial node to resume control of the heart's rhythm.
Key Considerations
- Cardioversion is particularly indicated for hemodynamically unstable patients with rapid ventricular rates causing hypotension, heart failure, or angina.
- For elective cardioversion, patients should receive anticoagulation for at least 3 weeks before the procedure if AF has been present for more than 48 hours or if duration is unknown, and anticoagulation should continue for at least 4 weeks afterward to prevent thromboembolism, as recommended by the 2024 ESC guidelines 1.
- Common anticoagulants include warfarin (target INR 2-3), direct oral anticoagulants like apixaban (5mg twice daily), rivaroxaban (20mg daily), or dabigatran (150mg twice daily).
- Alternatively, transesophageal echocardiography can be performed immediately before cardioversion to rule out left atrial thrombus, allowing immediate cardioversion with anticoagulation started beforehand, as supported by the 2024 ESC guidelines 1.
Procedure Details
- The procedure typically uses biphasic shocks starting at 120-200 joules, with sedation using agents like propofol or midazolam.
- Cardioversion is effective in 70-90% of cases initially, though many patients eventually relapse into AF, particularly those with structural heart disease, prolonged AF duration, or large left atrial size.
Clinical Decision Making
- The decision to perform electrical cardioversion should be based on individual patient characteristics, including the presence of hemodynamic instability, symptoms, and underlying heart disease, as well as the potential risks and benefits of the procedure, as outlined in the 2024 ESC guidelines 1.
From the Research
Rationale for Electrical Cardioversion of Atrial Fibrillation (AFib)
The rationale for electrical cardioversion of atrial fibrillation (AFib) is based on its safety, effectiveness, and reliability in aborting AF, especially in unstable situations 2. The procedure has undergone substantial evolution with developments in techniques and newer antiarrhythmic agents.
Clinical Applications and Techniques
Electrical cardioversion (ECV) is used to restore sinus rhythm (SR) in patients with AFib, which can improve quality of life (QoL) 3. The technique involves the use of biphasic waveforms, high-energy shocks, and manual pressure to increase the success of electrical cardioversion for AFib 4.
Efficacy and Safety
Studies have shown that electrical cardioversion is effective in terminating AFib, with a high success rate and low complication rate 5, 6. The procedure can be performed in an outpatient setting, which is feasible, safe, and has high patient acceptance 5. In the emergency department, electrical cardioversion for AFib has been shown to be largely safe and effective, with few serious complications 6.
Quality of Life and Patient Acceptance
Electrical cardioversion can improve QoL in patients with AFib, especially those who maintain sinus rhythm 3. Patients who undergo electrical cardioversion have reported high satisfaction and acceptance of the procedure, with most preferring an outpatient setting 5.
Key Factors Associated with Success
Key factors associated with the success of electrical cardioversion include: