Relationship between heart rate and outcomes in patients in sinus rhythm or atrial fibrillation with heart failure and reduced ejection fraction

Aims To investigate the relationship between heart rate and outcomes in heart failure and reduced ejection fraction (HFrEF) patients in sinus rhythm (SR) and atrial fibrillation (AF) adjusting for natriuretic peptide concentration, a powerful prognosticator. Methods and results Of 13 562 patients from two large HFrEF trials, 10 113 (74.6%) were in SR and 3449 (25.4%) in AF. The primary endpoint was the composite of cardiovascular death or heart failure hospitalization. Heart rate was analysed as a categorical (tertiles, T1-3) and continuous variable (per 10 bpm), separately in patients in SR and AF. Outcomes were adjusted for prognostic variables, including N-terminal prohormone of B-type natriuretic peptide (NT-proBNP), and also examined using change from baseline heart rate to 1 year (<= -10 bpm, >= +10 bpm, < +/- 10 bpm). SR patients with a higher heart rate had worse symptoms and quality of life, more often had diabetes and higher NT-proBNP concentrations. They had higher risk of the primary endpoint [T3 vs. T1 adjusted hazard ratio (HR) 1.50, 95% confidence interval (CI) 1.35-1.66; P < 0.001; per 10 bpm: 1.12, 95% CI 1.09-1.16; P < 0.001]. In SR, heart rate was associated with a relatively higher risk of pump failure than sudden death (adjusted HR per 10 bpm 1.17, 95% CI 1.09-1.26; P < 0.001 vs. 1.07, 95% CI 1.02-1.13; P = 0.011). Heart rate was not predictive of any outcome in AF. Conclusions In HFrEF, an elevated heart rate was an independent predictor of adverse cardiovascular outcomes in patients in SR, even after adjustment for NT-proBNP. There was no relationship between heart rate and outcomes in AF. Clinical Trial Registration: Identifiers NCT01035255 and NCT00853658.