LAUSR

Abstract Funding Acknowledgements Type of funding sources: None. Background the leadless pacing system, like Micra Transcatheter Pacing System (M-TPS) is precisely designed to reduce peri- and post-procedural complications, like pneumothorax, lead dislodgement, infections, and lead fracture.Previous studies have already demonstrated its good safety profile and the excellent electrical performance during the follow up. The study aimed to investigate feasibility and long-term electrical outcomes of M-TPS implant and estimate sex differences in leadless pacing. Methods All patients undergone M-TPS implantation in our Institution from May 2014 to October 2022 were included. All patients fulfilled standard criteria for VVI or VDD pacing according to guidelines. Device FU was scheduled at discharge, after 1 month and then every 6 months. Electrical performance was checked. Major complications were defined as life-threatening events, requiring surgical intervention or significant hemodynamic instability or resulting in death. Study population was divided between genders in order to analyze potential differences during the FU Results One hundred ninety-three consecutive patients [148 males, 76.7%, mean age 79 (IQR 73-84) y] were enrolled in this study. Indications for pacing were permanent AF with bradycardia in 107 (55.5%) patients, complete AV block in 59 (30.5%) patients, symptomatic sinus node dysfunction in 20 (10%) patients, and advanced AV block or bifascicular bock in 7 (4%). One hundred seventy-seven patients received VVI pacing, while 16 VDD. There were no statistically significant differences between groups for demographics characteristics (mean age at implant 79 vs 81, p=0.12), except gender. The mean was FU 12 (IQR 1-36) months, maximum 8 years. The implant procedure was successful in all patients and no complications were recorded. We observed no differences between groups in procedure duration [40 (IQR 30-60) min vs 40 (IQR 29-50), p=0.64], fluoroscopy time [9 (6-14) min vs 9 (7-11), p=0.81] and single device delivery (65.7% vs 65.9%, p=0.34). Electrical performance, except for pacing threshold at implantation [0.5 (IQR 0.38-0.75) V/0.24ms vs 0.38 (IQR 0.25-0.63) V/0.24ms, p=0.02), was similar between groups at discharge [pacing threshold 0.38 (IQR 0.38-0.63) V/0.24 ms vs 0.38 (IQR 0.25-0.55) V/0.24 ms, p=0.30; impedance 650 (IQR 560-760) Ohm vs 675 (IQR 580-780) Ohm, p=0.71; R wave amplitude 10.1 (IQR 7-16.2)mV vs 9.5 (IQR 7-14.45) mV, p=0.71] and during the FU [pacing threshold 0.5 (IQR 0.38-0.63) V/0.24 ms vs 0.5 (IQR 0.38-0.5) V/0.24 ms, p=0.11; impedance 570 (IQR 490-630) Ohm vs 580 (IQR 510-640) Ohm, p=0.46; R wave amplitude 11.5 (IQR 7.8-15.7)mV vs 12.7 (IQR 9-18) mV, p=0.26]. Conclusion Leadless pacing therapy is a feasible and safe alternative to conventional pacemakers with similar electrical performance and outcomes during a long-term FU. No differences were found between genders making it a good option especially in women who are often considered fragile in surgical procedure.