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Acute Heart Failure

Table of Contents

  • Key Points ⚡
  • Introduction
  • Aetiology & Pathophysiology
  • Causes
  • Clinical Features
  • Differential Diagnosis
  • Investigations
  • Management
  • Complications
  • References
  • Related Notes
  • Test Yourself

Key Points ⚡

  • Acute Heart Failure (AHF): rapid onset or worsening of heart failure symptoms; life-threatening; may be new onset or acute decompensation of chronic heart failure (CHF).
  • Common in adults >65 years; high mortality and hospital readmission rate.
  • Pathophysiology: failure of heart to pump blood → congestion (pulmonary/systemic) and hypoperfusion of organs.
  • Causes: new-onset (MI, valve dysfunction, arrhythmias); acute decompensation (infection, MI, uncontrolled hypertension, arrhythmias, worsening valve disease, medication non-adherence).
  • Symptoms: dyspnea, fatigue, ankle swelling, orthopnea, PND, pink frothy sputum, chest pain, palpitations, fever.
  • Investigations: vitals, ECG, BNP/NT-proBNP, ABG, bloods (FBC, U&E, CRP, troponin, TSH), D-dimer (if PE suspected), chest X-ray, echocardiogram, lung ultrasound.
  • Management: ABCDE approach, treat precipitating causes (CHAMP: ACS, hypertensive crisis, arrhythmias, mechanical issues, PE), oxygen therapy, loop diuretics, nitrates, NIV, inotropes/vasopressors if cardiogenic shock.
  • Long-term: optimize heart failure meds—ACEi/ARB, beta-blockers, aldosterone antagonists, specialist drugs (ivabradine, sacubitril-valsartan, hydralazine/nitrate, digoxin).
  • Prognosis: 40% readmission or death within 1 year; arrhythmias and thromboembolic events common.

Introduction

AHF is rapid worsening or onset of heart failure signs and symptoms resulting in inadequate cardiac output to meet metabolic demands. Leading cause of hospital admission in elderly UK patients.

Aetiology & Pathophysiology

  • Heart fails to pump adequately → pulmonary/systemic congestion (WET) and/or hypoperfusion (COLD).
  • ESC classifies patients as:
  • WET-WARM (50%): congestion without hypoperfusion
  • WET-COLD (45%): congestion with hypoperfusion
  • DRY-WARM or DRY-COLD (5%): no congestion, may or may not have hypoperfusion

Causes

New-Onset AHF

  • Acute myocardial dysfunction (e.g., MI)
  • Acute valve dysfunction
  • Arrhythmias

Acute Decompensation of CHF

  • Infection
  • Acute myocardial dysfunction
  • Uncontrolled hypertension
  • Arrhythmias
  • Worsening valve disease
  • Non-adherence to meds or diet
  • Inappropriate drug regimen changes (withdrawal or initiation)
  • Medications: steroids, NSAIDs

Clinical Features

History

  • Dyspnea, reduced exercise tolerance (NYHA class)
  • Ankle swelling (progression and height)
  • Fatigue
  • Pink frothy sputum
  • Orthopnea (pillows used)
  • Paroxysmal nocturnal dyspnea
  • Chest pain (ischemia, PE)
  • Palpitations
  • Fever (infection)
  • Medication compliance and recent changes

Examination

  • Signs of congestion:
  • Bilateral basal crackles
  • Peripheral edema
  • Raised JVP
  • Hepatomegaly
  • Gallop rhythm (S3/S4)
  • Murmurs
  • Signs of hypoperfusion:
  • Hypoxia
  • Tachypnea with accessory muscle use
  • Tachycardia
  • Cyanosis
  • Cold, pale, sweaty extremities
  • Oliguria
  • Confusion/agitation
  • Narrow pulse pressure

Differential Diagnosis

  • Asthma, COPD exacerbations
  • Pneumonia
  • Pulmonary embolism
  • Other causes of dyspnea

Investigations

Bedside

  • Vital signs: hypoxia (SpO2 <90%), tachycardia, tachypnea, BP variable (hypotension signals cardiogenic shock), narrow pulse pressure (<25% systolic BP)
  • ECG: often abnormal (ischemia, arrhythmias); normal ECG rare in AHF

Laboratory

  • BNP/NT-proBNP: sensitive but non-specific; low levels effectively rule out AHF
  • Arterial blood gas: type 1 or type 2 respiratory failure
  • Blood tests: FBC, U&E, CRP, troponin (elevated in MI or AHF), TSH
  • D-dimer: if PE suspected, interpret with clinical probability

Imaging

  • Chest X-ray: abnormal in ~80%; features include alveolar edema, Kerley B lines, cardiomegaly, dilated upper lobe vessels, pleural effusion
  • Echocardiography: assess biventricular function, valve disease, pericardial effusion, shunts, IVC status
  • Bedside lung ultrasound: B-lines (pulmonary edema), exclude other pathology

Management

Immediate

  • ABCDE approach
  • Identify and treat precipitating causes (CHAMP): ACS, hypertensive crisis, arrhythmias, mechanical problems, PE

Medical

  • Oxygen: titrate to 94-98% (88-92% in COPD); avoid hyperoxia
  • Loop diuretics: IV furosemide 40 mg initially; adjust dose for CKD or prior diuretics; monitor renal function and urine output
  • Nitrates: for congestion and ischemia; avoid if SBP <90 mmHg or aortic stenosis
  • Non-invasive ventilation (CPAP/BiPAP): for pulmonary edema and respiratory distress
  • Cardiogenic shock: early specialist input; consider inotropes (dobutamine) and vasopressors (adrenaline)

Long-Term

  • After stabilization: initiate/optimize
  • ACE inhibitors or ARBs (contraindications: angioedema, bilateral renal artery stenosis, hyperkalemia, severe renal impairment, severe AS)
  • Beta-blockers (start low, go slow; contraindicated in asthma, advanced AV block)
  • Aldosterone antagonists
  • Specialist drugs as indicated: ivabradine, sacubitril/valsartan, hydralazine/nitrate, digoxin
  • Follow-up within 2 weeks of discharge

Complications

  • High mortality and readmission rates (~40% within 1 year)
  • Arrhythmias, especially atrial fibrillation
  • Increased risk of stroke and thromboembolism

References

  • NICE Acute Heart Failure Guideline, 2014 [LINK]
  • European Society of Cardiology Guidelines for Diagnosis and Treatment of Acute and Chronic Heart Failure, 2016 [LINK]
  • Oxford Handbook of Clinical Medicine, 10th Ed. Wilkinson et al., 2017
  • BMJ Best Practice, Acute Exacerbation of Congestive Heart Failure, 2020 [LINK]
  • Chu et al. Mortality and Morbidity in Adults Treated with Liberal vs Conservative Oxygen Therapy (IOTA) Meta-analysis, 2018 [LINK]
  • Acute Coronary Syndrome (ACS)
  • Atrial Fibrillation (AF)
  • Atrioventricular Block
  • Brugada Syndrome
  • Bundle Branch Block

Test Yourself

  • [Link to quiz/flashcards on Acute Heart Failure]

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