Characterisation of Acute Residual Pulmonary Vein Connections Using Electroanatomical Mapping During Pulsed-Field Ablation of Atrial Fibrillation

Single-shot pulsed-field ablation (PFA) catheters show promising safety and efficacy for achieving pulmonary vein isolation (PVI) in atrial fibrillation (AF). However, additional PFA applications are sometimes required after standard PFA delivery to achieve PVI. To evaluate the real-world frequency and location of acute residual pulmonary vein (PV) connections using 3D electroanatomical mapping (3D-EAM) during index PFA. Patients undergoing index PVI with a single-shot PFA catheter and receiving post-ablation 3D-EAM were prospectively studied. First-pass isolation (FPI) rates and distribution of residual PV connections were assessed. A total of 535 patients from 48 international centres (89 operators) were included (paroxysmal AF [pAF]: 375; persistent AF [persAF]: 160). Mean procedure time was 75.9 ± 31.9 mins and mapping time 8.4 ± 5.2 mins. Ablation was performed with a pentaspline, variable conformation PFA catheter in 72.7% of cases and a fixed-loop PFA catheter in 27.3%. Bilateral FPI was achieved in 75.1% of patients (pAF 77.1% vs. persAF 70.6%; P=0.126). The individual PV FPI rate was 92.7% (1834 out of 1978 PVs). Excluding common PVs, residual PV connections were more frequent in superior PVs (superior 8.9% vs. inferior 3.8%; P<0.001), specifically in the left superior PV (10.1%). Predictors of FPI included standard four-vein anatomy (odds ratio 1.83 [95% CI 1.09-3.07]; P=0.021) and the pentaspline catheter (3.53 [1.81-6.87]; P<0.001). Using 3D-EAM, an acute residual connection of at least one PV was observed in a quarter of patients following standard PFA delivery and was most common in the left superior PV. Potential mechanisms include reversible electroporation, highlighting the potential need for additional lesions and the value of a mandatory post-PFA 'waiting period'.