β-Blocker Doses and Heart Rate in Patients with Heart Failure: Results from the National Norwegian Heart Failure Registry

Abstract

Background: Use of β-blockers and titration to the highest tolerated dose are highly recommended by the European Society of Cardiology (ESC) guidelines for treatment of chronic heart failure (HF) with a reduced ejection fraction (HFrEF), but little attention has been paid to the achieved heart rate (HR) during this treatment. Objectives: The aim of the present study was to examine the achieved HR in relation to the use of β-blockers in these patients. Methods: All of the patients (n = 2,689) in the National Norwegian Heart Failure Registry as part of the Norwegian Cardiovascular Disease Registry with a sinus rhythm and left ventricular ejection fraction (LVEF) <40% at stable follow-up visiting specialised hospital outpatient HF clinics in Norway were included. The β-blocker doses were calculated as a percent of the target dose according to ESC HF guidelines. Differences between baseline variables according to the achieved HR were analysed by the Student's t test for continuous variables and Pearson's χ2 test for categorical variables. Linear regression was used to determine the predictors of HR ≥70 beats/min (bpm) in the multivariate analysis. Results: One third of the patients had a resting HR ≥70 bpm. Of the patients with an HR ≥70 bpm, 72.3% used less than the target dose of β-blocker; they were younger and had a higher NYHA class, more diabetes mellitus and chronic obstructive pulmonary disease (COPD), and higher N-terminal pro-B type natriuretic peptide (NT-proBNP) levels and estimated glomerular filtration rates compared to the patients with an HR <70 bpm. The 1-year mortality was 3.1, 3.7, 5.8, and 9.1% among the patients with an HR <70, 70-79, 80-89, and >89 bpm, respectively. Only 2 patients used ivabradine. Conclusions: In patients with HFrEF and sinus rhythm, an HR ≥70 bpm was associated with worse clinical variables and outcomes. A high proportion of the patients who had an HR ≥70 bpm was not treated with or/did not tolerate the target dose of a β-blocker, although the β-blocker dose was higher than in patients with an HR <70 bpm. This may suggest that increased efforts should be made to further increase the β-blocker dose, and treatment with ivabradine could be considered among patients with an HR ≥70 bpm. Keywords: Chronic heart failure; Comorbidity; Heart rate; Mortality; β-Blocker.