Cardiac resynchronization therapy for enabling guideline-directed medical therapy optimization in heart failure

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).