Safety and device-device interactions of unipolar pulsed field ablation in patients with cardiac implantable electronic devices

Background The safety of pulsed-field ablation (PFA) in patients with cardiac implantable electronic devices (CIEDs) remains uncertain. Most evidence concerns bipolar PFA, which, despite potential electromagnetic interference during energy delivery, has not been linked to lasting CIED malfunction. Unipolar PFA generates a broader electromagnetic field that may increase interaction risk with nearby CIED components. Whether this results in a different impact on device function remains unknown. Purpose To assess the electrical and device-device interactions of unipolar PFA with CIEDs. Methods Consecutive patients with CIEDs undergoing atrial fibrillation (AF) ablation with a lattice-tip catheter were retrospectively enrolled at 3 European centres. Complete CIED interrogation, including sensing, impedance, and threshold, was performed before, immediately after, and 3 months post-ablation. Device reprogramming and temporary deactivation of defibrillation therapy were maintained throughout the procedure. The primary endpoint was any change in lead parameters immediately after ablation or at follow-up; the secondary endpoint was the occurrence of any periprocedural complications potentially related to unipolar PFA-CIED interaction. Results A total of 26 patients (mean age 70±7 years, 26% female) were included. Of these, 42% (n=11) had pacemakers (2 leadless, 9 dual-chamber) and 58% (n=15) defibrillators (4 single-chamber, 4 dual-chamber, 7 CRT-D). Indications were paroxysmal AF (12%), persistent AF (35%), and atrial tachycardia/flutter (53%). Ablation targets included the pulmonary veins (62%), posterior wall (62%), anterior line (15%), posterior mitral isthmus (72%), cavotricuspid isthmus (19%), crista terminalis (8%), and superior vena cava (8%). Mean PFA application number was 80±37. During PFA application, atrial and/or ventricular oversensing occurred, but no tachycardia or noise reversion episodes were documented. Unipolar PFA did not cause any significant changes in lead impedance, sensing, or thresholds immediately post-ablation or at 3-month follow-up (Figure). Two patients (8%) experienced procedural complications possibly related to PFA-CIED interaction. One patient with a dual-chamber pacemaker developed ventricular fibrillation during PFA at the posterior mitral isthmus, without evidence of acute ST-segment changes or coronary spasm on angiography. The second patient, with a leadless atrial pacemaker undergoing PFA at the crista terminalis, experienced post-procedural device reset with transitory decrease in battery voltage. Nominal battery voltage recovered 24 hours after ablation, with no changes in device parameters. Conclusion Although unipolar PFA did not determine significant changes in lead parameters immediately after the procedure or at 3-month follow-up, potential device-device interactions may occur, especially when energy is delivered near the leads. Larger prospective studies are needed to confirm these findings.