Po-455617-19 influence of posterior wall activity on af ablation outcomes: a capla substudy

A randomised trial (CAPLA study) of pulmonary vein isolation (PVI) vs empiric PVI + posterior wall isolation (PWI) did not improve AF outcomes in catheter ablation for persistent AF (PsAF). However PV and/or PW electrogram characteristics may identify a subset of patients in whom additional PWI is beneficial. To determine whether PV or PW AF cycle length predicts ablation outcomes in PVI with or without PWI for PsAF. Consecutive participants in spontaneous AF at the time of ablation were enrolled as part of the CAPLA study. PV, PW and left atrial appendage (LAA) cycle length (CL) were measured (longest, shortest, median) using a multipolar catheter for 100 consecutive cycles. We then evaluated the long-term impact of PV and PW CL on AF recurrence at 12 months follow up using twice daily ECG transmissions. 120 participants (24% female, 66±10 years, 20% LsPsAF, mean LAVI 52.4±15.7ml/m2, mean duration of continuous AF 8.6±10.0 months) were randomised to PVI alone (47.5%) vs PVI+PWI (52.5%) groups. Baseline clinical and echocardiographic characteristics were similar between groups (all p>0.05). Mean PV and PW CL were similar between groups (184±23 vs 176±21ms in PVI+PWI, p=0.053 and 180±21 vs 173±19ms p=0.082, respectively) with no difference in AF recurrence (54% in PVI vs 58% in PVI+PWI, Log Rank p =0.74. Shortest PW activity was independently associated with AF recurrence (HR 1.72 95% CI 1.24-4.23, p=0.040), whereas the presence of PV AF (p=0.14), PVCL (individual PVs or average of all 4 PVs) and PVCL heterogeneity were not (all p>0.05) regardless of ablation strategy. The addition of PWI was associated with greater arrhythmia-free survival (LogRank p=0.017, figure 1) in those with shorter PW activity (based on median PW<140ms). Short CL PW activity is associated with increased risk of AF recurrence post catheter ablation. The addition of PWI to PVI improved freedom from AF in the subset of patients with persistent AF with rapid PW activity.