The immediate trends in atrial electrical remodeling for paroxysmal atrial fibrillation across different modes of catheter ablation

Background Catheter ablation has emerged as a major strategy for paroxysmal atrial fibrillation (PAF). Atrial electrical remodeling (AER) plays a critical role in the recurrence of PAF after ablation. Hypothesis To characterize the immediate trends of AER during ablations in patients with PAF, and assess the relationship between immediate trends and recurrence. Methods We performed this prospective observational study of 135 patients to investigate AER following three ablation modes: radiofrequency ablation (RFA), cryoablation (CA) and 3D mapping-guided cryoablation (3D-CA). The atrial effective refractory period (AERP) and atrial conduction time (ACT) were measured via electrophysiology before and immediately after ablation, and P-wave indices were measured via electrocardiography before and within 24 h after ablation. Follow-up visits were conducted for at least 1 year or until relapse. Results Different approaches of ablation caused a fairly significant increase in the shortest P-wave duration and AERP in both the proximal coronary sinus (PCS) and distal coronary sinus (DCS) but caused a shortened P-wave dispersion. No different effect was found at the AERP among the three modes. Compared to patients who received CA, among patients who received RFA, a significant reduction in total ACT and right ACT was seen. Statistically, there was a weakly positive association between changes in total ACT and early recurrence. Conclusions Injury during ablation for PAF was associated with an increase in the AERP but not in the ACT. Total ACT and right ACT were shorter after RFA than after CA. The increase in total ACT were slightly predictive of early recurrence.