heart failure — diagnosis & classification
Contents
Syndrome of impaired ventricular filling or ejection causing dyspnoea, fatigue, and fluid retention. Classification by LVEF drives therapy: HFrEF (≤40%) has robust mortality-reducing GDMT; HFnrEF (>40%) has fewer proven interventions. Every HF patient needs an echocardiogram, an aetiological workup, and congestion assessment.
classification by LVEF — updated terminology (Oct 2025)
| Category | LVEF | Old term | Notes |
|---|---|---|---|
| HFrEF | ≤40% | HFrEF | quadruple therapy backbone |
| HFnrEF | >40% | HFmrEF (41–49%) + HFpEF (≥50%) | merged — ESC/CCS 2025 |
The HFmrEF/HFpEF distinction lacked therapeutic relevance — no drug has different efficacy across the >40% spectrum. Simplifies trial design and clinical decision-making.
NYHA functional classification
| Class | Description |
|---|---|
| I | no limitation of physical activity |
| II | slight limitation — comfortable at rest, symptoms with ordinary activity |
| III | marked limitation — comfortable at rest, symptoms with less than ordinary activity |
| IV | symptoms at rest — unable to carry on any activity without discomfort |
baseline investigations — all heart failure
| Test | Rationale |
|---|---|
| ECG | rhythm, conduction (LBBB for CRT eligibility), LVH, prior MI |
| TTE | LVEF, chamber size, valves, diastolic function, wall motion, pericardium |
| BNP / NT-proBNP | diagnosis (BNP >100, NT-proBNP >300 suggest HF); prognostication; response to therapy |
| troponin | rule out ACS as precipitant |
| CBC | anaemia (common comorbidity / decompensation trigger) |
| lytes, Cr, urea | baseline renal function; guide GDMT initiation and monitoring |
| ferritin + TSAT | iron deficiency common and treatable (even without anaemia) |
| TSH | hyper/hypothyroidism as reversible cause |
| lipids + HbA1c | CV risk management; SGLT2i eligibility regardless of diabetes |
aetiological workup
coronary artery disease assessment
- non-invasive ischaemia testing for all new HF — rule in/out ischaemic aetiology
- coronary angiography if:
- HF with angina
- LVEF ≤35% (revascularisation may improve outcomes in ischaemic cardiomyopathy)
- high pre-test probability of CAD
cardiac MRI
Indicated for non-ischaemic cardiomyopathy — helps distinguish:
| Finding | Suggests |
|---|---|
| mid-wall or epicardial LGE | myocarditis, sarcoidosis, DCM |
| subendocardial LGE in coronary distribution | ischaemic cardiomyopathy |
| diffuse subendocardial or RV LGE | amyloidosis |
| fatty infiltration + RV wall motion abnormalities | ARVC |
| increased native T1/T2 | oedema (active inflammation), infiltration |
New non-ischaemic cardiomyopathy, suspected infiltrative disease (amyloid, sarcoid), suspected ARVC, myocarditis, or when echo is non-diagnostic.
precipitants of decompensation
Mnemonic: FAILURES
| Letter | Cause |
|---|---|
| F | forgot medications (non-adherence) |
| A | arrhythmia (AF most common), anaemia |
| I | ischaemia / infarction, infection |
| L | lifestyle (dietary Na/fluid excess) |
| U | upregulation (pregnancy, thyrotoxicosis) |
| R | renal failure |
| E | embolism (PE) |
| S | stenosis (aortic) or other valvular progression |
assessing congestion and perfusion — the Nohria–Stevenson classification
| warm (adequate perfusion) | cold (hypoperfusion) | |
|---|---|---|
| dry (no congestion) | warm & dry — compensated (profile A) | cold & dry — may need inotropes/volume (profile L) |
| wet (congested) | warm & wet — diuretics (profile B) | cold & wet — most dangerous; inotropes + diuretics (profile C) |
Cardiogenic shock phenotype. Needs HF specialist involvement, often inotropes or MCS. Do NOT rely on diuretics alone — inadequate cardiac output limits renal drug delivery.