Cardioversion for Atrial Fibrillation: Anesthesia and Energy Levels

Analgésie et Sédation

The American College of Cardiology recommends that cardioversion be performed with the patient under adequate conscious sedation with short-acting anesthetic agents, and the initial recommended energy level is 200 J with an anteroposterior electrode configuration for optimal efficacy 1, 2
Cardioversion should be performed with the patient fasting and under adequate general anesthesia or conscious sedation, according to the American College of Cardiology 1, 3
Short-acting anesthetic medications or agents that produce conscious sedation are preferable to allow for rapid recovery after the procedure, as recommended by the European Heart Journal 2, 4
Overnight hospitalization is rarely necessary after cardioversion under appropriate sedation, as stated by the American College of Cardiology 1, 5

The anteroposterior electrode configuration is generally more effective than the anterolateral configuration, according to the American College of Cardiology 6, 1
A randomized study demonstrated that the anteroposterior configuration requires less energy and has a higher overall success rate (87%) compared to the anterolateral alignment (76%), as reported by the European Heart Journal 1, 5
For the anteroposterior configuration, the anterior electrode should be placed to the left of the sternum to reduce electrode separation, as recommended by the American College of Cardiology 6, 3

For atrial fibrillation, an initial energy level of 200 J or more is recommended with a monophasic waveform, according to the American College of Cardiology 1, 5
A similar recommendation to start at 200 J applies to biphasic waveforms, particularly for patients with long-standing atrial fibrillation, as stated by the European Heart Journal 1, 5
Studies have shown that a high initial energy level (360 J) is significantly more effective than lower levels (immediate success rate: 14% with 100 J, 39% with 200 J, and 95% with 360 J), as reported by the American College of Cardiology 1, 2

The electrical shock should be synchronized with the QRS complex, triggered by R-wave monitoring, according to the American College of Cardiology 1, 2
An appropriate ECG lead should be selected to well visualize atrial activation to facilitate outcome evaluation, as recommended by the European Heart Journal 1, 3
The biphasic waveform is more effective than the monophasic waveform, requiring fewer shocks and lower delivered energy, as stated by the American College of Cardiology 6, 1

For patients with implanted pacemakers or defibrillators, electrodes should be positioned as far as possible from the pulse generator, according to the American College of Cardiology 3, 4
The anteroposterior configuration is preferable for patients with implanted devices to reduce the risk of exit block, as recommended by the European Heart Journal 3, 4
Cardioversion is contraindicated in cases of digitalis toxicity or hypokalemia due to the risk of difficult-to-treat ventricular tachyarrhythmias, as stated by the American College of Cardiology 3, 4

The risks of cardioversion are mainly related to thromboembolism and arrhythmias, according to the American College of Cardiology 3, 4
Benign arrhythmias (ventricular and supraventricular extrasystoles, bradycardia, short periods of sinus arrest) may occur after cardioversion and usually disappear spontaneously, as reported by the European Heart Journal 3, 4