Consensus‐Recommended Follow‐Up Mediates Cardiovascular Outcomes Disparities Between Implantable Cardioverter Defibrillator and Pacemaker Recipients

BACKGROUND: Consensus-recommended follow-up after cardiac implantable electronic device (CIED) implantation improves outcomes, yet whether it mediates cardiovascular disparities between device types remains unknown. METHODS: We prospectively studied 6806 patients undergoing CIED implantation across a multi-hospital system (2019-2023; median follow-up 3.5 years), categorized as implantable cardioverter defibrillator (ICD) (n = 2757) or permanent pacemaker (PPM) (n = 4049). Causal mediation analysis decomposed the effect of device type on major adverse cardiovascular events (MACE) and device extraction into direct and follow-up mediated components, adjusting for demographics and comorbidities. RESULTS: ICD recipients had significantly lower consensus-recommended follow-up rates than PPM recipients (65.3% vs. 79.2%; adjusted OR 0.46, 95% CI 0.40-0.52, p < 0.001) and substantially higher MACE risk (HR 1.89, 95% CI 1.66-2.25, p < 0.001), of which 53.5% was mediated by follow-up adherence. Device extraction rates were lower in ICD recipients (HR 0.30, 95% CI 0.24-0.38), with only 7.9% mediated by follow-up adherence. CONCLUSIONS: More than half of the excess cardiovascular risk in ICD recipients was statistically mediated by suboptimal follow-up adherence-a potentially modifiable pathway. These findings identify follow-up adherence as a potentially important pathway and support further prospective investigation of strategies to improve monitoring and clinical outcomes in high-risk CIED populations.