Ab-452663-1 the impact of low posterior left atrial wall voltage on the outcomes of catheter ablation for persistent atrial fibrillation: a capla randomized clinical trial substudy

Pulmonary vein isolation(PVI) is less effective in patients with persistent atrial fibrillation(PsAF). Adjunctive ablation targeting low voltage areas(LVA) had demonstrated improved arrhythmia outcomes. To compare the outcomes of adding posterior wall isolation(PWI) to PVI, versus PVI alone, in PsAF patients with posterior wall LVA. The CAPLA study was a multi-centre, randomized trial involving PsAF patients randomized 1:1 to either PVI alone or PVI with PWI. Voltage mapping performed during pacing pre-ablation was reviewed offline, with LVA defined as bipolar voltage of <0.5mV. The primary endpoint was freedom from any documented atrial arrhythmia of >30 seconds off anti-arrhythmic medication (AAD) at 12 months, after a single ablation procedure in patients with posterior LVA. 210 patients (average 64.6+/-9.2years,73.3% males)underwent multipolar LA mapping. Posterior LVA was present in 32.9%(median surface area 0.6cm2), and associated with larger left atrial diameter(4.8cm vs 4.4cm, p<0.01). The addition of PWI to PVI did not significantly improve freedom from atrial arrhythmia recurrence over PVI alone(PVI with PWI 44.8% vs PVI 41.9%, HR0.95, 95%CI0.51-1.79; p=0.95). Compared to no posterior LVA, patients with posterior LVA were more likely to have LVA in other atrial regions(91.7% vs 57.1%, p<0.01), and significantly increased risk of atrial arrhythmia recurrence at 12 months (LVA 78.2% vs no LVA 44.2%; HR1.51, 95%CI 1.01-2.27, p=0.04). In patients with PsAF undergoing catheter ablation, posterior LVA was associated with a significant increase in atrial arrhythmia recurrence. However, the addition of PWI in those with posterior LVA did not reduce atrial arrhythmia recurrence over PVI alone.