In this document, we propose a universal definition of heart failure (HF) as a clinical syndrome with symptoms and/or signs caused by a structural and/or functional cardiac abnormality and corroborated by elevated natriuretic peptide levels and/or objective evidence of pulmonary or systemic congestion. We also propose revised stages of HF as: At risk for HF (Stage A), Pre‐HF (Stage B), Symptomatic HF (Stage C) and Advanced HF (Stage D). Finally, we propose a new and revised classification of HF according to left ventricular ejection fraction (LVEF). This includes HF with reduced ejection fraction (HFrEF): symptomatic HF with LVEF ≤40%; HF with mildly reduced ejection fraction (HFmrEF): symptomatic HF with LVEF 41–49%; HF with preserved ejection fraction (HFpEF): symptomatic HF with LVEF ≥50%; and HF with improved ejection fraction (HFimpEF): symptomatic HF with a baseline LVEF ≤40%, a ≥10 point increase from baseline LVEF, and a second measurement of LVEF > 40%.