When cardioverting patients in new atrial fibrillation, we want our first attempt to be our best attempt.
The Study
Schmidt A S. Antero-Lateral Versus Anterior-Posterior Electrode Position for Converting Atrial Fibrillation. Circulation. 2021;144:1995–2003.
The EPIC Trial(1) (Electrode Position In cardioverting Atrial Fibrillation) helps us answer not only the question of pad position, but also energy selection.
What they did
This was a multicentre, investigator initiated, randomised open-label, blinded-outcome assessment trial.
N= 468
Patients in this study were adult patients that were having elective cardioversion, with biphasic defibrillators. They were randomised to anterior-lateral or anterior-posterior pad placemant.
Synchronised biphasic shocks were delivered.
Escalating energy was used: 110J, 150J 200J and 360J.
Primary Outcome: Proportion of patients in sinus rhythm 1 minute after shock.
Secondary outcomes:
- Proportion of patients in sinus rhythm 1 minute after final shock delivered(maximum of 4 cardioversion shocks).
- Cardioversion efficacy 2 hours after cardioversion.
Safety outcomes included:
- Arrhythmias: asystole, atrioventricular blocks, transient bradycardia or ventricular arrhythmias
- Skin redness under electrodes
- Pain score by patient
What they found
Primary outcome ie patients in sinus rhythm 1 minute after the first shock was
- 54%(126 patients) in the antero-lateral position
- 33%(77) in the antero-posterior position
The number of patients in sinus rhythm after the final shock was:
- 93%(216 patients) in the anterior-lateral position and
- 85% (200 patients) in the anterior-posterior position.
- This translated to the number needed to treat of 14.
Use of the anterior-lateral position resulted in a significantly lower number of shocks needed.
There were no differences in safety outcomes.
My Take on This
This one is simple and helps shape clinical practice. The RAFF-2 trial(1) one year earlier, showed no difference in terms of pad positioning, the results here have changed my practice. I use anterior-lateral positioning of pads. Certainly I may change the pads ifI can’t cardiovert the patient in the first 2 shocks. Would you change pad positioning?
References
- Stiell IG et al. Electrical Versus Pharmacological Cardioversion for Emergency Department Patients with Acute Atrial Fibrillation (RAFF2): A Partial Factorial Randomised Trial. Lancet 2020. PMID: 32007169
