Defining
heart failure.
The foundation for the patient journey: what heart failure is, what supports the diagnosis, and how the condition changes over time.
Explore the definition ↘Heart failure is a clinical syndrome in which typical symptoms and signs, together with laboratory or imaging abnormalities indicating pulmonary or systemic congestion or altered cardiac output, are attributable to an underlying structural or functional cardiac abnormality.
Symptoms and signs
Breathlessness on exertion, orthopnoea, raised jugular venous pressure, lung crackles, a third heart sound, and peripheral or abdominal swelling contribute to the clinical picture.
A cardiac abnormality
Identify the structural or functional cardiac problem that explains the presentation. Imaging helps characterise the abnormality, establish the cause and guide treatment.
Objective evidence
Natriuretic peptides and imaging evidence of congestion or raised filling pressures increase diagnostic confidence. Integrate the findings: the diagnosis rests on a comprehensive assessment.
Recognise the risk
The consensus distinguishes people at risk, those with pre-HF, and those with current or previous symptomatic heart failure. Select a stage to explore the distinction.
At risk of heart failure
Risk factors are present, but there are no current or previous HF symptoms or signs, structural cardiac changes or elevated cardiac biomarkers. Examples include hypertension, diabetes, obesity, cardiotoxic exposure or a family history of cardiomyopathy. Not everyone progresses to HF.
Read the phenotype,
not just the ejection fraction.
Ejection fraction
The 2026 consensus groups HF into reduced, preserved and improved EF categories, moving away from rigid numerical boundaries in its universal classification. EF remains important for applying trial evidence and selecting treatment; specific treatment recommendations still require their own eligibility criteria.
The cause
Go beyond “ischaemic” or “non-ischaemic”. Describe the specific disease where possible: for example, valvular disease, an inherited cardiomyopathy, inflammation or amyloidosis. Identifying the cause may open a targeted treatment pathway.
The trajectory
Describe whether the patient is improving, stable or worsening. Improvement in EF or symptoms does not automatically erase an established HF diagnosis. Remission, recovery and persistent disease require assessment over time.
Walsh MN and colleagues. AHA/ACC/ESC/WHF Expert Consensus Document: Second Universal Definition of Heart Failure (2026). Circulation. 2026;154:e279–e293. Definition: p. e280; stages: Table 1, p. e281; phenotypes: pp. e281–e282.
Read the consensus document ↗