Heart Failure

Contents. #Details · #Key Facts · #Classification · #Pathophysiology · #Diagnosis · #Decompensated heart failure · #Advanced heart failure · #Special populations · #Contradictions / Open Questions · #Sources

Detailed pages. entities/HFrEF — the reduced-EF phenotype: definition, pathophysiology, diagnosis, HFimpEF. entities/HFpEF — the preserved-EF phenotype: diagnostic scores, the ASE algorithm, latent HFpEF.

Management pages. concepts/HFrEF-Management — four pillars, additional agents, revascularisation, ICD/CRT/TEER. concepts/HFpEF-Management — outcome trials, SGLT2i and MRA, obesity-HFpEF, iron. Decompensation: concepts/Decompensated-HF-Management.

Details

Heart failure is a clinical syndrome of symptoms (dyspnoea, ankle swelling, fatigue) and/or signs (elevated JVP, pulmonary crackles, peripheral oedema) caused by a cardiac structural or functional abnormality that raises intracardiac pressures or limits cardiac output at rest or on effort. The 2026 ESC guideline abolished HFmrEF and divided HF into two phenotypes only — HFrEF at LVEF <50% and HFpEF at LVEF ≥50% — on the argument that LVEF 41–49% behaves like HFrEF in aetiology, pathophysiology and treatment response. Stages A–D, previously an ACC/AHA construct, are now adopted by both guidelines, which is what gives the classification a lever for intervening before symptoms appear. (sources/HF-ESC-2026, rating: very high; sources/HF-AHA-2022)

The distinction that matters clinically is what follows from it. SGLT2 inhibitors and MRAs are now Class I, Level A in all symptomatic HF regardless of ejection fraction, so both phenotypes share two foundational drugs; what separates them is everything else — HFrEF adds a beta-blocker and a renin-axis inhibitor, HFpEF adds nothing but comorbidity control, and only HFrEF has device therapy with randomised mortality evidence. (sources/HF-ESC-2026)

Key Facts

Classification

LVEF phenotypes — ESC 2026 versus ACC/AHA 2022

The two guidelines no longer share a classification. ESC abolished HFmrEF in 2026 and raised the HFrEF ceiling to 50%; AHA/ACC/HFSA kept four categories in 2022 and is still the reference used in the United States.

Phenotype ESC 2026 ACC/AHA/HFSA 2022 Consequence of the difference
HFrEF LVEF <50% + symptoms and/or signs LVEF ≤40% + symptoms and/or signs ESC covers the whole 41–49% band; AHA splits it off as HFmrEF
HFmrEF Abolished — absorbed into HFrEF LVEF 41–49% plus evidence of raised filling pressures (natriuretic peptides, non-invasive or invasive haemodynamics) A patient at 45% is HFrEF in Europe and HFmrEF in the US, and inherits different recommendation sets
HFpEF LVEF ≥50%, never previously <50%, + structural/functional abnormality + raised natriuretic peptides LVEF ≥50% + evidence of raised filling pressures Only ESC has the "never previously <50%" clause, which routes recovered-EF patients to HFimpEF rather than HFpEF
HFimpEF Prior LVEF <50% with ≥10% absolute rise to >40% Previous LVEF ≤40% with follow-up >40% Same clinical intent — remission, not recovery — but different entry points and a different denominator
Staging Stages A–D, newly adopted Stages A–D, originators The one part of the classification both now share

(Table: sources/HF-ESC-2026, rating: very high; sources/HF-AHA-2022)

Therapy maps onto the same split. If 41–49% is HFrEF, the band inherits the full four foundational drugs at Class I; if it is HFmrEF, it gets an SGLT2i at COR 2a and everything else at COR 2b. Identical trial data, materially different treatment intensity. Mechanisms: entities/HFrEF and entities/HFpEF. Pathways: concepts/HFrEF-Management and concepts/HFpEF-Management.

Why HFmrEF was abolished — and why it survives in the US

HFmrEF existed from 2016 to 2026 and was never backed by a dedicated trial: the 41–49% band was always analysed as a subgroup, and both pivotal SGLT2i trials enrolled LVEF >40% rather than 41–49% specifically. The 2026 Task Force retired it because its aetiology, pathophysiology (reduced contractility rather than increased stiffness) and treatment response all resemble HFrEF. Two things follow: the European recommendation is stronger than its evidence, and the American guideline still treats the band as a distinct entity requiring documented raised filling pressures. The disagreement is really about whether 41–49% is a phenotype or a transition state. (sources/HF-ESC-2026, rating: very high; sources/HF-AHA-2022)

Staging A–D

The A–D stages are orthogonal to the LVEF phenotypes — a patient has both. Adopting them was one of the few classification changes the ESC made in the AHA's direction.

Stage Definition Action
A — At risk Risk factors only (hypertension, diabetes, obesity, cardiotoxin exposure, family history); no structural disease, symptoms or biomarkers SBP <130 mmHg (I/A); SGLT2i in T2DM at risk or with CKD (I/A); finerenone in T2DM with CKD (I/A); GLP-1 RA IIa/A
B — Pre-HF Structural disease, elevated filling pressures or elevated BNP/troponin without symptoms or signs ACE-I/ARB if LVEF ≤40% (I/A); beta-blocker if LVEF <50% (I/B1); eplerenone after MI with LVEF ≤40% plus HF or diabetes (I/B1)
C Structural disease with current or prior symptoms Foundational medical therapy, additional therapy, device therapy, comorbidity control
D Advanced: persistent severe symptoms and cardiogenic impairment despite optimised therapy Advanced HF centre referral (I/A), transplant, LVAD, inotropes, palliative care

(Table: sources/HF-ESC-2026, rating: very high; sources/HF-AHA-2022)

Stage B is where the two guidelines earn their keep: the ESC 2026 beta-blocker recommendation now extends to LVEF <50%, not the older ≤40%, on the strength of an individual-patient meta-analysis showing similar mortality reduction at LVEF 40–50%.

HFimpEF

Pathophysiology

Diagnosis

Natriuretic peptides and structural criteria

Cardiac troponin in decompensated heart failure

Drug thresholds in chronic kidney disease

The eGFR at which each drug must be started or stopped is where most HF prescribing actually stalls. Cross-cutting thresholds are here; the phenotype-specific ordering is on concepts/HFrEF-Management and concepts/HFpEF-Management. (sources/CVD-CKD-ESC-2026, rating: very high)

Echocardiography

Resting echocardiography establishes the structural signature — chamber size, wall thickness, LA volume, diastolic grade, RV function — and excludes the alternative explanations that change management: significant valvular disease, HCM, constrictive pericarditis and cardiac amyloidosis. LVEF should be reported from a modality with adequate endocardial definition, and CMR is preferred when the EF is borderline or an infiltrative or inflammatory cause is suspected. Full diastolic algorithm: concepts/LV-Diastolic-Function. (sources/HF-ESC-2021, rating: very high)

Cardiac amyloidosis

Invasive haemodynamics

Right heart catheterisation is the reference standard when non-invasive assessment is equivocal, and it is required before transplant listing and for LVAD candidacy. It also defines the acute HF phenotypes — isolated LV failure, isolated RV failure and biventricular failure — and stages cardiogenic shock. All of that detail, including the HFpEF exercise criteria, LVAD ramp testing and the PAWP measurement pitfalls, sits on concepts/Right-Heart-Catheterization. (sources/rhc-hf-ehj-2025, rating: high)

Remote pulmonary artery pressure monitoring (CardioMEMS, Cordella) is established for NYHA II–III disease with recent hospitalisation or elevated natriuretic peptides: rising pressures precede clinical congestion by days to weeks, allowing proactive diuretic titration. See concepts/Right-Heart-Catheterization. (sources/hemodynamic-hf-pht-aha-2026, rating: very high)

Iron deficiency

Diagnose by transferrin saturation <20% or serum ferritin <100 μg/L. Applies to HFrEF and HFmrEF; intravenous iron is not currently recommended in HFpEF. (sources/HF-update-ESC-2023, rating: very high) Full evidence: concepts/Iron-Deficiency-in-HF.

Decompensated heart failure

The 2026 ESC guideline replaced "acute heart failure" with decompensated heart failure and split it into four clinical categories — decompensated left-sided heart failure, decompensated right-sided heart failure, acute pulmonary oedema, and cardiogenic shock. Management from presentation through the six-week post-discharge window is on concepts/Decompensated-HF-Management; the shock category in full is on concepts/Cardiogenic-Shock. (sources/HF-ESC-2026, rating: very high)

What belongs on this page is the fact that decompensation is where HF outcomes are decided, and the decisive interventions are in-hospital: an SGLT2 inhibitor started after stabilisation (I/B1), and rapid pre-discharge initiation and up-titration of foundational therapy with close follow-up over six weeks (I/B2 — STRONG-HF, readmission or death at 180 days 23.3% → 15.2%). The chronic pathway resumes when that window closes.

Advanced heart failure

Special populations

Clonal haematopoiesis

Pulmonary hypertension associated with left heart disease

Perioperative management

Obesity

Genetic testing and precision medicine

Contradictions / Open Questions

Connections

Sources