Effects of selective heart rate reduction with ivabradine on left ventricular remodelling and function: results from the SHIFT echocardiography substudy.

Abstract

The SHIFT echocardiographic substudy evaluated the effects of ivabradine on left ventricular (LV) remodelling in heart failure (HF). Eligible patients had chronic HF and systolic dysfunction [LV ejection fraction (LVEF) ≤35%], were in sinus rhythm, and had resting heart rate ≥70 bpm. Patients were randomly allocated to ivabradine or placebo, superimposed on background therapy for HF. Complete echocardiographic data at baseline and 8 months were available for 411 patients (ivabradine 208, placebo 203). Treatment with ivabradine reduced LVESVI (primary substudy endpoint) vs. placebo [-7.0 ± 16.3 vs. -0.9 ± 17.1 mL/m(2); difference (SE), -5.8 (1.6), 95% CI -8.8 to -2.7, P< 0.001]. The reduction in LVESVI was independent of beta-blocker use, HF aetiology, and baseline LVEF. Ivabradine also improved LV end-diastolic volume index (-7.9 ± 18.9 vs. -1.8 ± 19.0 mL/m(2), P= 0.002) and LVEF (+2.4 ± 7.7 vs. -0.1 ± 8.0%, P< 0.001). The incidence of the SHIFT primary composite outcome (cardiovascular mortality or hospitalization for worsening HF) was higher in patients with LVESVI above the median (59 mL/m2) at baseline (HR 1.62, 95% CI 1.03-2.56, P= 0.04). Patients with the largest relative reductions in LVESVI had the lowest event rates. Ivabradine reverses cardiac remodelling in patients with HF and LV systolic dysfunction.