Seed-configuration pulsed field ablation for arrhythmogenic substrate beyond pulmonary vein isolation
T Mews, I Rattka, D Federle, G Mastella, N Jurik, C Poch, K L Laugwitz, M RattkaAbstract
Background
Pulmonary vein isolation (PVI) remains the standard therapy for patients with atrial fibrillation (AF). However, a substantial proportion of treated patients still experience AF recurrence, frequently driven by insufficient long-term lesion durability leading to pulmonary vein (PV) reconnection and, consequently, the renewed potential for pulmonary vein triggers to induce AF. Although direct ablation further within the veins might eliminate the trigger itself, such an approach has traditionally been restricted by the risk of pulmonary vein stenosis with thermal ablation techniques. Owing to its non-thermal and tissue selective approach, PFA has been proven to allow safe intrapulmonary ablation and may thus overcome this limitation. This study therefore investigated whether additional PFA applications deeper inside the pulmonary vein using a “seed” strategy improve rhythm control beyond standard PVI.
Method
In this single-centre case-control study, 285 consecutive patients undergoing first time ablation for persistent or paroxysmal AF were included. The study group (n=53) underwent PFA followed by two additional intrapulmonary seed applications per vein. The control group (n=232) was treated with conventional PVI, using either PFA, cryoballoon (CBA), or radiofrequency ablation (RFA). The primary endpoint was freedom from AF/atrial tachycardia (AF/AT) recurrence at 12 months.
Results
All PVs were successfully isolated in both groups, without major periprocedural complications such as PV stenosis, cardiac tamponade or death. Besides from a higher prevalence of prior myocardial infarction in the study group (25% vs 11%, p = 0.011), baseline characteristics did not differ between groups. At one year the study group demonstrated a significantly lower risk of AF/AT recurrence compared to the control group (9% vs 37%; log rank: p < 0.001). When analysing the three ablation modalities within the control group separately, it becomes evident that all have similarly high risks of arrhythmia recurrence at the 12-month mark (PFA: 37%; CBA: 40%; RFA: 25%; log rank: p = ns). Apart from paroxysmal AF (HR: 3.23; CI: 1.76-5.92; p < 0.001), the subsequent multivariable analysis identified treatment with seed strategy as the only strong independent predictor of sinus rhythm maintenance and therefore procedural success (HR: 3.32; CI: 1.12-9.86; p = 0.031).
Conclusions
Our findings suggest that two additional intrapulmonary PFA applications using a seed configuration appear not only feasible and safe, but are associated with improved one-year freedom from atrial arrhythmia recurrence. This benefit may result from the direct modification of the arrhythmogenic pulmonary vein substrate, thereby potentially overcoming the limitations of PVI durability and subsequent PV reconnection. Further studies are required to verify our findings.