Abstract

Aims We aimed to assess whether cardiac resynchronization therapy (CRT) might serve as an enabler for guideline‐directed medical therapy (GDMT) optimization. Methods and results Patients with heart failure with reduced ejection fraction (HFrEF) enrolled in the Swedish Heart Failure Registry between January 2009 and August 2022 were considered. Patients receiving a CRT close to the index registration were the cases, whereas controls had not received a CRT despite having an indication. Overall, 1543 (25%) HFrEF cases and 4537 (75%) controls were analysed in the intention‐to‐treat analysis. At baseline, beta‐blockers, angiotensin‐converting enzyme inhibitor (ACEi), angiotensin receptor blocker (ARB) or angiotensin receptor–neprilysin inhibitor (ARNi), mineralocorticoid receptor antagonist (MRA) and loop diuretic use was 84% versus 86%, 89% versus 88%, 57% versus 46% and 62% versus 59% in patients receiving versus not receiving CRT, respectively. At 1.5‐year follow‐up, patients receiving a CRT more likely experienced an improved use/dose of beta‐blocker therapy (46% vs. 35%) and decreased loop diuretic use/dose (30% vs. 24%) versus controls. These associations were consistent after adjustments (odds ratio [OR] 1.83, 95% confidence interval [CI] 1.58–2.13, and OR 1.26, 95% CI 1.07–1.48, respectively), and confirmed in the per‐protocol analysis (i.e. after excluding controls who received a CRT during follow‐up). A significant association between CRT and the likelihood of ACEi/ARB/ARNi and MRA optimization (OR 1.22, 95% CI 1.04–1.44, and OR 1.25, 95% CI 1.05–1.50, respectively) was observed in the per‐protocol analysis. Conclusions In this large nationwide real‐world population with HFrEF, CRT implantation was associated with enabled use/dose of heart failure GDMT and decreased loop diuretic need (use/dose).