Premature battery depletion in patients with subcutaneous implantable cardioverter-defibrillators: incidence and outcomes from the nationwide french HONEST cohort

Background Subcutaneous implantable cardioverter-defibrillators (S-ICDs) are an effective alternative to transvenous systems. However, premature battery depletion (PBD) has emerged as a relevant recall, potentially leading to early reintervention and associated procedural risk. Manufacturer-issued advisories highlighted accelerated depletion in certain EMBLEM™ devices, but independent real-world data remain very limited. Purpose To assess the incidence, timing, and impact of PBD in a large multicentre nationwide French cohort. Methods We analysed data from 4,924 patients implanted with S-ICD models 1010, A209, and A219 between 2012 and 2019 within the HONEST (coHOrte fraNçaise des dEfibrillateurs Sous cuTanés) cohort. PBD was defined as elective replacement indicator (ERI) reached within 60 months without shock delivery, or >25% absolute loss in projected battery longevity over 12 months requiring replacement before 90 months. Clinical characteristics, timing of depletion, and early and late local complications were compared between PBD and normal battery depletion (NBD) groups. Results PBD occurred in 462 patients (9.4%) during a mean follow-up of 4.2 ± 2.2 years. Of these, 45.5% developed PBD within 5 years post-implantation. Mean time from implantation to PBD diagnosis was 4.8 ± 1.2 years, with generator replacement performed after 54 ± 19 days from diagnosis. Overall, premature battery depletion was associated with an estimated 1.5-year reduction in device longevity compared to normal depletion (6.3 ± 0.9 years). No sudden deaths occurred between diagnosis and replacement. Among PBD patients, 93.7% were implanted with 2nd/3rd-generation devices compared with 65.7% in the NBD group (p < 0.001). Across the implantation period (2012–2019), the likelihood of PBD remained low during the first four years post-implantation, but increased markedly from the fifth year onward, reaching a cumulative incidence of 32.1% at eight years. Rates of local early complications, including infection (2.4% vs. 2.0%, p = 0.805) and pocket hematoma (2.4% vs. 2.6%, p = 0.818), were comparable between PBD and NBD groups. Considering both early and late complications, compared to NBD, we found no differences in the proportion of cases requiring reintervention (2.4% vs. 2.3%, p = 1.000). Conclusion Premature battery depletion occurred in about 1 in 10 S-ICD patients, predominantly involving newer-generation devices, with incidence rising sharply from the fifth-year post-implantation. Our findings confirm the clinical relevance of PBD and show that timely generator replacement remains safe, with no increase in complications compared to replacements for NBD.