Impact of Prolonged Cycle Length Resulting From Conversion of Atrial Fibrillation to Atrial Tachycardia on Ablation Outcome in Persistent Atrial Fibrillation Ablation.

There is limited available data regarding the impact of cycle length (CL) prolongation when converting atrial fibrillation (AF) to organized atrial tachycardia (AT) and its effect on clinical outcomes. We retrospectively screened and included a cohort of 132 patients with persistent or long-standing persistent AF who underwent circumferential pulmonary vein isolation (CPVI) and left atrial substrate modification (LASM) between January 2015 and October 2019. In all 132 consecutive patients, persistent AF was successfully converted into organized AT. For cases with recurrence after a 3-month blanking period, a repeat procedure was conducted. We observed a notable prolongation in CL after ablation (average increase of 56.6 ± 30 ms). Following a median follow-up duration of 9.5 ± 5.1 months, 27 patients experienced recurrence. Through receiver operating curve (ROC) analysis, a prolonged CL cut-off of 42.5 ms was identified, with a specificity of 71% and a sensitivity of 59.4%. Patients were categorized into two groups: those with CL less than 42.5 ms (group A, = 48) and those with CL more than 42.5 ms (group B, = 84). The Kaplan-Meier survival curves demonstrated a significantly higher recurrence-free rate after catheter ablation in group B compared to group A ( = 0.002). Upon termination of persistent AF into AT during ablation, it was found that CL prolongation beyond 42.5 ms was associated with improved freedom from arrhythmia.