Key Facts

Acute heart failure (AHF) is the rapid onset or worsening of signs and symptoms of heart failure. It may present as a first episode (de novo) or more commonly as an acute decompensation of chronic heart failure (ADCHF). It is a medical emergency requiring urgent assessment and treatment.

Epidemiology

• ~80,000 admissions per year in England
• Accounts for ~5% of all emergency medical admissions
• Mean age at presentation: ~75 years
• In-hospital mortality: ~5-10%
• 30-day readmission rate: ~25%
• 1-year mortality post-discharge: ~25-30%

Aetiology

Precipitants of acute decompensation:

• Acute coronary syndrome
• Arrhythmia (especially new-onset AF with rapid ventricular rate)
• Medication non-adherence or dietary indiscretion
• Infection/sepsis
• Uncontrolled hypertension
• Acute valvular dysfunction (MR, AR)
• Pulmonary embolism
• Renal failure
• Anaemia
• Thyrotoxicosis

Pathophysiology

• Acute increase in LV filling pressures → pulmonary congestion → pulmonary oedema
• Neurohormonal activation (RAAS, SNS) causes vasoconstriction and fluid retention
• Forward failure: reduced cardiac output → hypoperfusion
• Backward failure: elevated filling pressures → congestion
• Acute pulmonary oedema: fluid transudation into alveoli impairs gas exchange

Acute Pulmonary Oedema

• Severe dyspnoea, orthopnoea, paroxysmal nocturnal dyspnoea
• Pink frothy sputum
• Bilateral fine crepitations
• Tachypnoea, tachycardia
• Elevated JVP
• Third heart sound (S3)
• Hypoxia

Cardiogenic Shock

• Hypotension (SBP <90 mmHg)
• Cold, clammy peripheries
• Oliguria (<0.5 mL/kg/h)
• Confusion, altered consciousness
• Elevated lactate

Right Heart Failure Predominant

• Peripheral oedema
• Elevated JVP
• Hepatomegaly, ascites
• Right-sided pleural effusion

Red Flags

• SBP <90 mmHg (cardiogenic shock)
• SpO₂ <90% despite high-flow oxygen
• Respiratory rate >25/min
• Altered consciousness
• Concurrent acute MI

Bedside

• ECG: ischaemia, arrhythmia, LVH
• Observations: HR, BP, SpO₂, RR, urine output
• ABG: hypoxia, type 1 respiratory failure, metabolic acidosis (if shock)

Bloods

• NT-proBNP (or BNP): >300 pg/mL supportive; also prognostic
• Troponin: exclude ACS as precipitant
• U&Es: renal function, electrolytes
• FBC: anaemia, infection
• LFTs: hepatic congestion
• CRP: infection screen
• Lactate: tissue perfusion
• TFTs: thyroid dysfunction

Imaging

• Chest X-ray: upper lobe venous distension, bilateral alveolar shadowing, Kerley B lines, cardiomegaly, pleural effusions
• Echocardiography: urgent — assess LV/RV function, valvular abnormalities, pericardial effusion
• Lung ultrasound: B-lines (interstitial oedema) — increasingly used at bedside

Special Tests

• Coronary angiography: if ACS precipitant
• Pulmonary artery catheterisation: in refractory shock (rarely needed)

Non-pharmacological

• Sit patient upright (reduces venous return and work of breathing)
• High-flow oxygen if SpO₂ <94%
• Continuous monitoring: ECG, SpO₂, BP, urine output
• Fluid restriction: 1.5L/day
• Daily weights

Pharmacological

Acute management (wet and warm — congested, adequate perfusion):

• IV furosemide 40-80mg bolus (or double usual oral dose if already on furosemide); repeat/increase as needed
• If poor response: furosemide infusion 5-40mg/hour or add metolazone 2.5-10mg OD (sequential nephron blockade)
• GTN infusion 1-10mg/hour: if SBP >90 mmHg (reduces preload and afterload)
• Do NOT routinely give morphine (NICE NG106 — increased ICU admission and mortality)
• CPAP/BiPAP: if persistent respiratory distress despite initial treatment (improves oxygenation and work of breathing)

Cardiogenic shock (wet and cold):

• Dobutamine 2.5-10 mcg/kg/min (inotrope)
• Noradrenaline if significant hypotension (vasopressor)
• Milrinone: phosphodiesterase inhibitor (inodilator)
• Levosimendan: calcium sensitiser (limited UK availability)
• Consider mechanical circulatory support: IABP, Impella, VA-ECMO

Before discharge:

• Initiate/optimise HFrEF quadruple therapy before discharge where possible
• SGLT2 inhibitor can be started in hospital (EMPULSE trial)
• Arrange specialist heart failure follow-up within 2 weeks of discharge
• Cardiac rehabilitation referral
• Medication reconciliation and patient education

Surgical/Interventional

• PCI/CABG if ACS precipitant
• Valve surgery/intervention if acute valvular cause
• Mechanical circulatory support for refractory cardiogenic shock
• Ultrafiltration for diuretic-resistant fluid overload

Referral Criteria

• All patients: specialist heart failure team review during admission
• Cardiogenic shock: intensive care and/or advanced HF centre
• Refractory to medical therapy: consider transplant assessment

• In-hospital mortality: ~5-10%
• 30-day mortality: ~10-15%
• 1-year mortality post-discharge: ~25-30%
• 30-day readmission rate: ~25%
• Prognosis worse with: cardiogenic shock, ACS trigger, low SBP at admission, high BNP, renal dysfunction
• De novo AHF generally has better prognosis than ADCHF
• Each hospitalisation for HF is associated with progressive decline and worsened outcomes

Clinical Profiles in Acute Heart Failure

CXR Signs of Heart Failure (ABCDE)