Aims: We assessed the interplay between hyperkalaemia (HK) and renin–angiotensin–aldosterone system inhibitor (RAASi) use, dose and discontinuation, and their association with all-cause or cardiovascular death in patients with chronic heart failure (HF). We hypothesized that HK-associated increased death may be related to RAASi withdrawal. Methods and results: The ESC-HFA-EORP Heart Failure Long-Term Registry was used. Among 9222 outpatients (HF with reduced ejection fraction: 60.6%, HF with mid-range ejection fraction: 22.9%, HF with preserved ejection fraction: 16.5%) from 31 countries, 16.6% had HK (≥5.0 mmol/L) at baseline. Angiotensin-converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB) was used in 88.3%, a mineralo...