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
Causes
De Novo Acute Heart Failure
- Acute coronary syndrome (esp. myocardial infarction) – 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 to 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
Initial test: chest X-ray
- Chest X-ray can be used to support the diagnosis of heart failure and exclude alternative diagnoses
- A combination of typical clinical features and chest X-ray findings is usually sufficient to diagnose acute heart failure and initiate treatment
- 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)
Confirmatory test: transthoracic echocardiogram [NICE CG187]
- In cases of de novo acute heart failure → consider performing within 48 hours of admission to guide early specialist management
Role of serum BNP or NT-proBNP [NICE CG187]
- It is recommended to help exclude heart failure
- Heart failure would increase the levels of BNP and NT-proBNP, therefore heart failure is unlikely if the levels are NOT elevated (BNP < 100 ng/L or NT-proBNP < 300 ng/L)
Since many other conditions may raise BNP and NT-proBNP levels (e.g. CKD, COPD, pulmonary embolism); role of serum BNP or NT-proBNP is limited to excluding heart failure (i.e. an elevated serum BNP or NT-proBNP level is NOT diagnostic of heart failure alone)
Do NOT routinely offer pulmonary artery catheterisation to patients with acute heart failure [NICE CG187]
Other tests: [NICE CG187]
- Blood tests
- FBC (anaemia can cause / worsen dyspnoea and exacerbate heart failure; ↑ WCC may suggest an underlying infection)
- U&Es (detect renal impairment, which may cause / worsen fluid overload)
- LFTs (heart failure may cause congestive hepatopathy)
- TFT (thyroid dysfunction can affect cardiac function; hyperthyroidism can also precipitate AF)
- Lipid profile (to identify dyslipidaemia as coroanry artery disease is an important cause of heart failure)
- HbA1c (to identify diabetes, which is an important cardiovascular risk factor and influences heart failure management)
- ECG (to assess for underlying / precipitating cardiac causes)
- Urinalysis (to assess for renal disease)
- PEF or spirometry (to assess for obstructive lung diseases as alternative or co-existing cause of dyspnoea)
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 nitrates 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 AKI / 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 is 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]