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Background: Left bundle branch area pacing (LBBAP) has emerged as a physiological alternative pacing strategy to biventricular pacing (BIVP) in cardiac resynchronization therapy (CRT). We aimed to assess the impact of LBBAP vs. BIVP on all-cause mortality and heart failure (HF)-related hospitalization in patients undergoing CRT., Methods: Studies comparing LBBAP and BIVP for CRT in patients with HF with reduced left ventricular ejection fraction (LVEF) were included. The coprimary outcomes were all-cause mortality and HF-related hospitalization. Secondary outcomes included procedural and fluoroscopy time, change in QRS duration, and change in LVEF., Results: Thirteen studies (12 observational and 1 RCT, n = 3239; LBBAP = 1338 and BIVP = 1901) with a mean follow-up duration of 25.8 months were included. Compared to BIVP, LBBAP was associated with a significant absolute risk reduction of 3.2% in all-cause mortality (9.3% vs 12.5%, RR 0.7, 95% CI 0.57-0.86, p < 0.001) and an 8.2% reduction in HF-related hospitalization (11.3% vs 19.5%, RR 0.6, 95% CI 0.5-0.71, p < 0.00001). LBBAP also resulted in reductions in procedural time (mean weighted difference- 23.2 min, 95% CI - 42.9 to - 3.6, p = 0.02) and fluoroscopy time (- 8.6 min, 95% CI - 12.5 to - 4.7, p < 0.001) as well as a significant reduction in QRS duration (mean weighted difference:- 25.3 ms, 95% CI - 30.9 to - 19.8, p < 0.00001) and a greater improvement in LVEF of 5.1% (95% CI 4.4-5.8, p < 0.001) compared to BIVP in the studies that reported these outcomes., Conclusion: In this meta-analysis, LBBAP was associated with a significant reduction in all-cause mortality as well as HF-related hospitalization when compared to BIVP. Additional data from large RCTs is warranted to corroborate these promising findings., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Introduction: The need to detect impending implantable cardiac defibrillator (ICD) lead failure has grown. Automated sensing diagnostics have been developed for this reason. The sensing integrity counter (SIC) is one such oversensing diagnostic, which forms an integral part of the Medtronic™ lead integrity alert (LIA) feature on implantable defibrillators. It records nonphysiologic short VV intervals (NPSVVIs). It is unclear whether SIC data derived from integrated bipolar (IBP) leads need to be interpreted differently when compared to true bipolar (TBP) leads. We hypothesized that IBP ICD leads by virtue of a larger "antennae" may generate more NPSVVIs on than TBP leads, leading to more false-positive SIC counts., Methods: Equal durations of remote monitoring records of 44 patients (mean age of 65.9 ± 2.2 years, 52 % female) with IBP ICD leads and Medtronic (MDT) generators (IBP group) were compared with those of 44 randomly selected patients (64.0 ± 2.2 years, 24 % female) who had TBP ICD leads and MDT generators (TBP group). Mean surveillance time, defined as the time over which the cumulative SIC count was acquired, was 614 ± 44 days (TBP group) vs. 620 ± 49 days (IBP group, p = ns). The mean time of follow-up following the first documented short VV interval was 115.2 months in the integrated bipolar group and 66.9 months in the true bipolar group. Leads on advisory were excluded from the study., Results: A total of 26/44 patients in the IBP group displayed NPSVVI compared to 11/44 patients in the TBP group (59 vs. 25 %; p = 0.002, Fisher exact test). When adjusted for gender and lead age, the difference was still significant (p = 0.008). When evaluating the clinical consequence of NPSVVI in this cohort, 3/11 TBP leads with NPSVVI of >0 were eventually extracted due to additional abnormalities vs. 0/26 IBP leads with NPSVVI (p = 0.02, Fisher exact test). None of the IBP group patients with NPSVVI have developed inappropriate therapy from lead noise or a need for abandonment or extraction., Conclusion: Integrated bipolar ICD leads are more likely to have elevated SIC counts than true bipolar leads despite revealing no other evidence of lead failure. There does not appear to be a need for heightened surveillance in IBP leads with observed elevated SIC counts that have no other findings to suggest lead malfunction.