Background In patients with refractory atrial fibrillation (AF), atrioventricular nodal (AVN) ablation and permanent pacemaker implantation is recommended. The Micra Transcatheter Pacing System™ (Micra) is a single chamber leadless pacemaker (LPM) and thus offers the possibility of AV node (AVN) ablation in the same procedure. Pacing threshold (PT) elevation after radiofrequency (RF) ablation is a potential complication. Methods We conducted a single center retrospective cohort study. All patients implanted with a Micra (n=84) and concomitant or delayed AVN ablation (n=12) from 2014 to 2022 were included. We describe two cases of acute Micra PT elevation immediately following RF AVN ablation requiring device retrieval and implantation of a new Micra. Procedural characteristics and electrophysiological parameters were analyzed, and computer modelling was performed to determine factors responsible for acute PT elevations. Results A total of 84 patients were included. Mean age was 74±10 and 48% were women. Twelve patients (14%) underwent AVN ablation. Two patients had acute PT elevation requiring device retrieval despite no direct contact of the ablation catheter with the Micra. Computer modelling shows that significant dissipated power due to electrical field coupling can occur at the tip or ring electrode if the catheter is not kept at a safe distance (≥15 mm) from the Micra. Conclusion Concurrent AVN ablation and Micra implantation is safe in most patients. To prevent acute PT elevation, keeping a safe distance of ≥15 mm from the tip and ring electrodes of the Micra and using lower power output may prevent this complication.

Introduction: Percutaneous left atrial appendage closure (LAAC) is an alternative to oral anticoagulant (OAC) in patients with non-valvular atrial fibrillation (AF) and contraindication to long-term OAC. Combined strategy with percutaneous LAAC at the same time of other cardiac structural or electrophysiological procedure has emerged as an alternative to staged strategy. Aim: To describe our experience of combined LAAC procedures using Watchman™ devices. Method: All patients with combined LAAC procedure using Watchman™ (WN) devices performed from 2016-2021 were included. The primary safety endpoint was a composite of periprocedural complications and adverse events during follow-up. The primary efficacy endpoint included strokes, systemic embolisms, major bleeding, and cardiovascular death. Results: Since 2016, among the 157 patients who underwent LAAC using WN devices, 16 underwent a combined strategy: 6 TEMVR (37%), 6 typical atrial flutter ablation (37%), 2 LP implantation (13%) and 2 atrial fibrillation ablation (13%). The WN device was successfully implanted in 98% and 100% for single and combined LAAC respectively (p = 0.63). Median follow-up was 13 months (IQR 25/75 3/24) in the whole cohort. Device related complications occurred in 6 out of 141 patients (4%) who underwent single LAAC and in no (0/16) patient in the combined LAAC procedure (p=ns). The procedural related complications did not differ significantly between groups (5% vs 12%, respectively in the single and combined group, p=0.1). Conclusion: Combined procedure combining LAAC using the Watchman™ devices and one other structural or electrophysiological procedure is safe and effective. Larger series are needed to confirm these results.