Impact of implantable cardioverter defibrillators on mortality in heart failure receiving quadruple guideline-directed medical therapy: a propensity score-matched study.

Background: In the contemporary management of heart failure with reduced ejection fraction (HFrEF), the recommended quadruple guideline-directed medical therapy (GDMT) consists of angiotensin receptor-neprilysin inhibitor (ARNI), evidence-based beta-blockers (BB), mineralocorticoid receptor antagonists (MRA), and sodium-glucose cotransporter-2 inhibitors (SGLT-2i). This study explored the impact of adding implantable cardioverter-defibrillator (ICD) therapy to this comprehensive regimen in HFrEF patients.

Methods: Utilizing deidentified data from the National Electronic Database of the Turkish Ministry of Health, we conducted a nationwide retrospective cohort study on 5450 HFrEF patients receiving quadruple GDMT, including ARNI. Among them, 709 patients underwent additional ICD or cardiac resynchronization therapy defibrillator (CRT-D) implantation. Propensity score matching ensured balanced baseline characteristics between groups. Primary endpoint was determined as all-cause mortality.

Results: In the matched cohort, all-cause mortality occurred in 108 out of 619 patients (17.4%) in the GDMT group and 101 out of 619 patients (16.3%) in the ICD group, with a hazard ratio (HR) of 0.74 and a 95% confidence interval (CI) ranging from 0.57 to 0.98. The median follow-up time was 1365 days in the matched cohort, 1283 days in the GDMT group. Subgroup analyses consistently demonstrated benefits, particularly among individuals aged 61 years and older (HR: 0.60, 95% CI: 0.42-0.87, p = 0.006), those with sinus rhythm (HR: 0.55, 95% CI: 0.34-0.89, p = 0.013), individuals not using amiodarone (HR: 0.61, 95% CI: 0.42-0.89, p = 0.011), and those with an estimated glomerular filtration rate lower than 61.9 (HR: 0.66, 95% CI: 0.48-0.91, p = 0.011).

Conclusions: This study may offer a glimmer of hope that even after achieving the best current optimal medical therapy, the addition of device therapy could still yield positive outcomes in the management of patients with HFrEF.