Time to benefit of heart rate reduction with ivabradine in patients with heart failure and reduced ejection fraction

Abstract

Aims: In the SHIFT (Systolic Heart failure treatment with the I_f inhibitor ivabradine Trial, ISRCTN70429960) study, ivabradine reduced cardiovascular death or heart failure (HF) hospitalizations in patients with HF and reduced ejection fraction (HFrEF) in sinus rhythm and with a heart rate (HR) ≥70 bpm. In this study, we sought to determine the clinical significance of the time durations of HR reduction and the significant treatment effect on outcomes among patients with HFrEF.

Methods and results: The time to statistically significant reduction of the primary outcome (HF hospitalization and cardiovascular death) and its components, all-cause death, and HF death, were assessed in a post-hoc analysis of the SHIFT trial in the overall population (HR ≥70 bpm) and at HR ≥75 bpm, representing the approved label in many countries. Compared to placebo, the primary outcome and HF hospitalizations were significantly reduced at 102 days, while there was no effect on cardiovascular death, all-cause death, and HF death at HR ≥70 bpm. In the population with a baseline HR ≥75 bpm, a reduction of the primary outcome occurred after 67 days, HF hospitalization after 78 days, cardiovascular death after 169 days, death from HF after 157 days and all-cause death after 169 days.

Conclusion: Treatment with ivabradine should not be deferred in patients in sinus rhythm with a HR of ≥70 bpm to reduce the primary outcome and HF hospitalizations, in particular in patients with HR ≥75 bpm. At HR ≥75 bpm, the time to risk reduction was shorter for reduction of hospitalization and mortality outcomes in patients with HFrEF after initiation of guideline-directed medication, including beta-blockers at maximally tolerated doses.

Keywords: Cardiovascular outcomes; Heart failure; Heart rate; Ivabradine.