Acute Heart Failure
Acute heart failure is a rapid onset or worsening of heart failure symptoms caused by the heart’s inability to pump blood effectively, often leading to pulmonary oedema, fluid overload, or cardiogenic shock.
This article covers the causes, signs/symptoms, diagnosis, investigations, and emergency management of acute heart failure in clinical practice.
Diagnosis and management is based on available NICE guidelines [CG187] Acute heart failure: diagnosis and management.
Background Information
Definition
There are 2 main types of acute heart failure:
- De novo acute heart failure: sudden onset of heart failure in someone with no history or diagnosis of heart failure
- Acute decompensated chronic heart failure: acute worsening of symptoms in someone with established chronic heart failure
Aetiology
De Novo Acute Heart Failure
- Acute coronary syndrome – most common and important
- Acute valvular disease
- Acute myocarditis
- Arrhythmias
Acute Decompensated Chronic Heart Failure
- Acute infections (e.g. respiratory tract infection, UTI)
- Non-adherence with medication / dietary restrictions
- Atrial fibrillation and other arrhythmias
- Acute coronary syndrome
- Uncontrolled hypertension
- Anaemia
Complications
Main complications are:
- Haemodynamic instability (can cause cardiogenic shock)
- Pulmonary congestion
- End-organ hypoperfusion
Diagnosis
Clinical Features
Symptoms
Pulmonary and systemic congestion are the main presenting features:
- Pulmonary congestion (from left ventricular failure)
- Sudden onset dyspnoea and orthopnoea
- Cough +/- pink frothy sputum
- Systemic congestion (from right ventricular failure)
- Peripheral oedema
- Weight gain
Examination Findings
Pulmonary and systemic congestion are the main presenting features:
- Pulmonary congestion (from left ventricular failure)
- Bi-basal crackles
- Cardiac wheeze
- S3 gallop rhythm
- Systemic congestion (from right ventricular failure)
- Raised JVP
- Peripheral oedema
- Ascites
- Congestive hepatopathy
Investigation and Diagnosis
Diagnostic Tests
Initial diagnostic test: chest X-ray
- A combination of typical clinical features and chest X-ray findings is usually sufficient to diagnose acute heart failure and initiate treatment
Measure serum BNP or NT-proBNP level to rule out heart failure
- Heart failure is unlikely if: BNP < 100 ng/L or NT-proBNP < 300 ng/L
- Many other conditions (e.g. CKD, COPD, pulmonary embolism) would raise BNP / NT-proBNP; therefore it is only useful to rule out heart failure, but not to help diagnose heart failure
Confirmatory test: trans-thoracic echocardiogram
- If de novo acute heart failure → perform within 48 hours of admission
Typical chest X-ray findings in heart failure are (ABCDE):
- A: Alveolar oedema (perihilar bat wing opacities – from fluid accumulation in alveolar spaces)
- B: Kerley B lines (short horizontal lines at peripheral lung margins – from interstitial oedema)
- C: Cardiomegaly (>50% of thoracic width) (NB heart size can ONLY be assessed in a PA chest X-ray)
- D: Dilated upper lobe vessels (↑ left atrial pressure → redistribution of blood to upper lobes)
- E: Pleural effusion (typically bilateral transudative effusion)
Work Up
A standard heart failure workup includes:
- Chest X-ray
- ECG
- Blood tests (FBC, LFT, U&E, TFT, lipid profile, HbA1c)
- Urinalysis
- Peak flow or spirometry
Management
Acute Heart Failure
1st line: IV loop diuretic (furosemide 40-120 mg / bumetanide 1-3 mg) – to relieve congestive symptoms
Add-on therapy:
- IV nitratesIntravenous nitrates, primarily nitroglycerin, act as potent venous and, at higher doses, arterial vasodilators, rapidly reducing preload and, to a lesser extent, afterload. This mechanism leads to decreased cardiac filling pressures and pulmonary congestion, with symptomatic improvement in dyspnea and relief of pulmonary edema, especially in patients with elevated or normal blood pressure if there is:
- Concomitant myocardial ischaemia, or
- Severe hypertension, or
- Aortic or mitral regurgitation
- Ventilatory support
- CPAP can be used in severe cardiogenic pulmonary oedema
- Endotracheal intubation and mechanical ventilation – last resort
Do not routinely discontinue long-term heart failure medications, unless there are clear contraindications:
- Beta blocker should be stopped if HR <50 bpm / shock / 2nd or 3rd degree heart block
- ACE inhibitors should only be stopped if there is AKIAcute kidney injury / shock
Acute Cardiogenic Shock
1st line management: IV vasopressors (e.g. noradrenaline, adrenaline) or inotropes (e.g. dobutamine)
- US guidelines recommend noradrenaline as 1st line, and only to add inotropes if ineffective [Ref]
- Inotropes and vasopressors should be titrated to lowest effective dose (e.g. to maintain mean arterial pressure >65 mmHg)
Management beyond inotropes and vasopressors are complicated and individualised in intensive care setting, key principles are:
- Treating underlying cause (e.g. revascularisation for myocardial infarction)
- Early invasive hemodynamic assessment (e.g. pulmonary artery catheterisation) to guide management
- Consideration for temporary mechanical circulatory support
Diuretics (e.g. furosemide) and vasodilators (e.g. nitrates) should generally be avoided in the initial management of cardiogenic shock with hypotension, as they may worsen perfusion and precipitate further hemodynamic compromise. [Ref]
References
NICE guideline Acute heart failure: diagnosis and management