Responsiveness to bepridil predicts atrial substrate in patients with persistent atrial fibrillation

BACKGROUND: The low voltage zone (LVZ) detected with three‐dimensional electroanatomical mapping is a surrogate marker of atrial scar in patients with persistent atrial fibrillation (PeAF) and is associated with poor clinical outcomes after catheter ablation. However, fewer studies have reported the relationship between responsiveness to antiarrhythmic drugs and the LVZ. METHODS: We retrospectively analyzed 76 patients who underwent catheter ablation for PeAF at our center. Rhythm control with bepridil was initiated before ablation in all patients, and electrical cardioversion was performed in cases of failure to restore sinus rhythm with bepridil alone. Patients with successful sinus restoration with bepridil alone (≤200 mg/d) were defined as “responders”, while those who required electrical cardioversion as well were defined as “non‐responders”. We compared the LVZ ratio (ratio of the LVZ surface area to the left atrium surface area on three‐dimensional electroanatomical mapping) and the recurrence‐free rate after ablation between the two groups. RESULTS: Of the 76 patients, 48 (63.2%) were responders to bepridil. The median LVZ ratio was significantly lower in the responder group than in the nonresponder group (7.5% vs 14.0%, P = .009). Multivariate analysis revealed that response to bepridil was an independent predictor of normal voltage (P = .02, odds ratio = 0.20, 95% confidence interval = 0.04‐0.76). The recurrence‐free rate at 1 year after catheter ablation was significantly higher in the responder group than in the nonresponder group (87.1% vs 62.3%, P = .03). CONCLUSIONS: Response to bepridil is a marker of normal voltage in electroanatomical mapping and is significantly associated with better clinical outcomes after catheter ablation.