The newly defined category of heart failure (HF) with mid-range ejection fraction (HFmrEF; EF 40–49 %) is beginning to be characterised but little is known about the potential for treating it. Trials and observational studies suggest that standard therapy for HF with reduced ejection fraction (HFrEF; EF <40 %) may also offer some benefit to patients with EF ≥40 %; however, any difference between its effects on HFmrEF and true HF with preserved ejection fraction (HFpEF) have until now not been explored. This study summarises randomised trial data from the CHARM programme that suggest that candesartan may improve outcomes in HFmrEF