Longevity of contemporary subcutaneous implantable cardioverter-defibrillators: multicenter real-world data

Background The subcutaneous implantable cardioverter-defibrillator (S-ICD) provides effective protection against sudden cardiac death while avoiding transvenous leads. Real-world data on the longevity of contemporary S-ICD systems are still limited. Objective To assess the real-world longevity of current-generation S-ICDs and identify factors influencing battery performance in a multicenter, remotely monitored cohort. Methods Data from 2,130 EMBLEM S-ICD devices enrolled in the LATITUDE remote monitoring network across 24 Italian centers (2015–2025) were analyzed. Devices affected by the 2019 advisory on premature battery depletion or with an implant duration <3 months (n=241) were excluded. Longevity was defined as device duration plus the estimated remaining battery life at the latest remote transmission Results Median follow-up was 2.7 years (IQR 1.5–4.1). At the latest transmission, the estimated remaining battery life was 68 ± 19%. Median estimated device longevity was 9.0 years (IQR 8.7–9.2), approximately two years longer than manufacturer projections. Shock burden was the main determinant of reduced longevity: patients experiencing ≥2 shocks per year had an estimated lifespan shorter than those without shocks (7.0 vs. 9.1 years; p<0.001) (Figure 1). The effect of in-office interrogations and remote transmissions on battery life was negligible (<0.1 year). Devices implanted for >6 years showed slightly shorter estimated longevity compared to those implanted for 1–2 years (8.9 vs. 9.3 years; p<0.001). Conclusions In a large real-world cohort, contemporary S-ICD systems showed excellent and predictable longevity, exceeding manufacturer expectations. Battery performance was minimally affected by telemetry activity, while frequent shock delivery modestly reduced lifespan.