Anterior Upper Lateral Versus Anterior-Lateral Electrode Positions for External Cardioversion in Atrial Fibrillation

Electrical cardioversion is the first-line rhythm control therapy for symptomatic persistent atrial fibrillation (AF). Although the anterior-posterior and anterior-lateral electrode positions are widely used as the standard for external cardioversion in the current guidelines, they are ineffective in > 10% of patients. Therefore, we assessed the efficacy of the anterior upper lateral electrode positioning on defibrillation electrodes during cardioversion in AF.In this randomized, investigator-initiated, open-label trial, we randomly assigned patients with AF scheduled for elective cardioversion to either the anterior-lateral or anterior-posterior electrode positioning groups. The primary outcome was the proportion of patients with sinus rhythm after the first shock. The secondary outcome was the proportion of patients in sinus rhythm after up to 3 shocks escalating to maximum energy. Safety outcomes included arrhythmia during or after cardioversion, skin redness, and patient-reported periprocedural pain.We randomly selected 333 patients. The primary outcome occurred in 125 (75%) patients in the anterior upper lateral electrode position group and 88 (53%) patients in the anterior-lateral electrode position group (risk difference, 22 percentage points, 95% CI: 14-35; P < 0.001). After the final cardioversion shock, 155 (93%) patients were in the anterior upper lateral electrode positioning group and 141 (85%) patients were in the anterior-posterior electrode positioning group (risk difference, 8 percentage points, 95% CI: 2-15). There were no significant differences in any safety outcomes between the groups.The anterior upper lateral electrode positioning was more effective than the anterior-lateral electrode positioning for biphasic cardioversion in AF. There were no significant differences in the safety outcomes.