When cardioverting patients in new atrial fibrillation, we want our first attempt to be our best attempt.
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(2) (Read it here) 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?
Reference
- Schmidt A S. Antero-Lateral Versus Anterior-Posterior Electrode Position for Converting Atrial Fibrillation. Circulation. 2021;144:1995–2003.
- 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
