Appropriate ICD Therapies in Primary Prevention: A Propensity‐Matched Comparison of Contemporary and Historic Heart Failure Cohorts

ABSTRACT Background In heart failure with reduced ejection fraction (HFrEF), a substantial proportion of deaths are arrhythmic. Implantable cardioverter‐defibrillators (ICDs) are recommended for primary prevention in patients with left ventricular ejection fraction (LVEF) ≤ 35% despite guideline‐directed medical therapy (GDMT), but landmark trials predate widespread use of angiotensin receptor–neprilysin inhibitors (ARNI) and sodium–glucose cotransporter 2 inhibitors (SGLT2i), raising uncertainty about arrhythmic risk in the contemporary treatment era. Methods We retrospectively studied consecutive HFrEF patients undergoing primary‐prevention ICD implantation at a single center (2015–2022), categorized into historical‐era and contemporary‐era cohorts by ARNI/SGLT2i adoption. Propensity‐score matching balanced baseline characteristics. The primary endpoint was time to first appropriate ICD therapy (antitachycardia pacing or shock). Results Of 289 patients (mean age 62 ± 11 years, 82% male), 234 (117 per group) remained after matching. Mean follow‐up was 51 months. Appropriate ICD therapy incidence did not differ significantly between contemporary‐era and historical‐era cohorts (hazard ratio [HR] 1.52, 95% CI 0.84–2.72; p = 0.165). Competing‐risk‐adjusted cumulative incidence was numerically higher in the contemporary‐era cohort at a pre‐specified 36‐months horizon, consistent with a sensitivity analysis using an expanded propensity‐score model (HR 1.55, 95% CI 0.82–2.94). Conclusion ICD therapy rates were not significantly different between the contemporary‐era and historical‐era cohorts, a finding robust to sensitivity and competing‐risk analyses. These results should be interpreted cautiously, as the study may be underpowered to detect modest differences, and clinically relevant effects cannot be excluded.