BACKGROUND The short-term safety, feasibility, and performance of the Medtronic SelectSecure 3830-69 cm pacing lead for conduction system pacing (CSP) has been reported; however, its longer-term performance is not well established. OBJECTIVE: The purpose of this study is to examine the long-term performance of the 3830 lead for His Bundle Pacing (HBP) and Left Bundle Branch Area Pacing (LBBAP). METHODS: We retrospectively reviewed all cases of CSP performed with the Medtronic SelectSecure 3830-69 cm pacing lead at Cleveland Clinic Florida between May 2016 and October 2021. RESULTS: Of 515 attempts, HBP achieved an 85% success rate (340 cases), while LBBAP demonstrated a higher success rate of 97.4% (150 cases). The mean follow-up was 28 months for HBP and 14 months for LBBAP, with patient ages averaging 75 and 77 years, respectively. Only 7% of the cohort had an ejection fraction below 50%. The primary indications for HBP were sick sinus syndrome (35.5%), atrioventricular block (35.2%), cardiac resynchronization therapy (10%), and refractory atrial fibrillation (18.8%), with similar distributions for LBBAP. The HBP group's capture threshold at implant was 1.3 ± 0.8 V at 0.8 ± 0.2 ms, which significantly increased at chronic follow-up to 1.68 ± 1.3 V at 0.7 ± 0.3 ms (p <0.001), whereas the LBBAP group's capture threshold remained stable from 0.8 ± 0.5 V at 0.5 ± 0.3 ms to to 0.9 ± 0.5 V at 0.5 ± 0.3 ms, (p= 0.35). Lead revisions were more common in the HBP group (50 cases) than in the LBBAP group (5 cases), with exit block rates of 11.7% and 3%, respectively. CONCLUSION: Using the 3830 lead for HBP can result in significantly elevated thresholds, loss of His-bundle capture, and frequent lead revision rates at long-term follow-up. These issues are less commonly seen when the lead is used for LBBAP.

Dr. Baez-Escudero, serve as a consultant to Abbott and Aziyo biologics. All other authors have reported that they have no relationships relevant to the content of this paper to disclose.

After beginning our work we came to know of an opportunity for funding via Medtronic's investigator-initiated research program to which we were accepted. However, we assure you that any potential conflict of interest has not influenced the design, execution, or reporting of this study, and our findings are presented objectively.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

Institutional Review Board Cleveland Clinic Foundation 9500 Euclid Avenue Cleveland, OH 44195 Telephone: 800.223.2273 Fax: 216.445.4094

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes

Data will be made available upon reasonable request.