Heart failure is a clinical syndrome caused by cardiac dysfunction usually secondary to myocardial muscle loss or dysfunction.
It is characterized by either left ventricular hypertrophy or dilation or both.
It leads to neurohormonal and circulatory abnormalities.
Acute heart failure is the rapid onset of or change in the signs and symptoms of heart failure.
It arises as a result of deterioration in patients previously diagnosed with heart failure or may also be the first presentation of heart failure.
It is characterized by pulmonary congestion, decreased cardiac output and tissue perfusion.
It is a life-threatening condition that needs immediate medical attention.


  • The diagnosis of acute heart failure is based on clinical findings supported by appropriate diagnostic exam performed urgently after first patient contact; identifies patients in cardiogenic shock and respiratory failure


Clinical Conditions of Acute Heart Failure

Patients with acute heart failure may present in one of the following clinical categories

Worsening or Decompensated Heart Failure

  • Usually with a history of progressive worsening of chronic heart failure on treatment and evidence of systemic and pulmonary congestion
  • Hypotension on admission is associated with a poor prognosis

Pulmonary Edema

  • Patients present with severe respiratory distress, tachypnea, orthopnea, and with rales over the lung fields
  • Arterial O2 saturation is usually <90% on room air prior to oxygen therapy
  • Confirmed by chest radiography

Hypertensive Heart Failure

  • Signs and symptoms of heart failure accompanied by high blood pressure and preserved left ventricular function (heart failure with preserved ejection fraction)
  • Evidence of increased sympathetic tone with tachycardia and vasoconstriction
  • May be mildly hypervolemic or euvolemic with signs of pulmonary congestion without signs of systemic congestion
  • Rapid response to appropriate treatment and low hospital mortality

Cardiogenic Shock

  • Tissue hypoperfusion induced by heart failure after adequate correction of preload and major arrhythmia
  • Characterized by reduced systolic blood pressure [Systolic blood pressure (SBP) <90 mmHg or a decrease of mean arterial pressure (MAP) >30 mmHg] and absent or low urine output of <0.5ml/kg/hour
  • Rhythm disturbance is common
  • Pulmonary congestion and organ hypoperfusion develop rapidly
  • There is continuum from low cardiac output syndrome to cardiogenic shock

Isolated Right Heart Failure

  • Low output syndrome in the absence of pulmonary congestion with elevated jugular venous pressure, with or without hepatomegaly and low left ventricular filling pressures

Acute Coronary Syndrome (ACS) and Heart Failure

  • Some patients with acute coronary syndrome present with symptoms and signs of heart failure
  • Episodes of heart failure are associated with or precipitated by arrhythmia
  • Patients are managed according to the ACS guidelines

Acute Mechanical Causes

  • Conditions include acute incompetence of the native or prosthetic valve due to endocarditis, aortic dissection or thrombosis, cardiac intervention or chest trauma

Physical Examination

  • Assess level of dyspnea, hemodynamic status and heart rhythm to determine degree of cardiopulmonary instability
  • Vital signs (eg low or high blood pressure, bradycardia, tachycardia with pulsus alternans, irregular pulse, tachypnea, increased work of breathing, respiratory rate <8 breaths/minute despite dyspnea, intolerance of supine position)
  • Hypoperfusion (eg cold sweated extremities, oliguria, narrow pulse pressure, altered mental status, dizziness)
    • Often accompanied by but is not synonymous with hypotension
  • Congestion: Left-sided [bilateral pulmonary rales, bilateral peripheral edema (eg ankle, sacral, scrotal)] or right-sided (elevated jugular venous pressure, bilateral peripheral edema, hepatomegaly, ascites, hepatojugular reflux)
  • Murmurs
  • Laterally displaced or prominent apex beat
  • S3 gallop and accentuated pulmonic component of the 2nd heart sound
  • Based on the physical exam, acute heart failure can be classified based on the presence or absence of congestion and/or hypoperfusion
    • Warm-dry: Both congestion and hypoperfusion are absent
    • Warm-wet: Congestion present but without hypoperfusion
    • Cold-dry: Hypoperfusion present but without congestion
    • Cold-wet: Both congestion and hypoperfusion are present

Laboratory Tests

  • Complete blood count (CBC), serum electrolytes, blood urea nitrogen (BUN), creatinine, glucose, troponin, uric acid, calcium, magnesium, albumin, lipid profile, liver enzymes, bilirubin, ferritin, total iron-binding capacity (TIBC), cardiac enzymes, thyroid function tests, internal normalized ratio (INR), C-reactive protein (CRP), D-dimer and urinalysis
    • To detect reversible/ treatable causes of heart failure (HF) and presence of other co-morbidities
  • Electrocardiogram (ECG)
    • To assess cardiac rhythm, conduction, electrical dyssynchrony, chamber enlargement, QTc interval, and presence of myocardial infarction (MI) or ischemia; has a high negative predictive value
    • Performed immediately in patients with suspected cardiogenic shock
  • Plasma natriuretic peptide [eg B-type natriuretic peptide (BNP), N-terminal pro-BNP (NT-proBNP), mid-regional pro atrial natriuretic peptide (MR-proANP)]
    • Acute heart failure is associated with increased plasma levels of natriuretic peptides
      • Thresholds: BNP <100 pg/mL, NT-proBNP <300 pg/mL, MR-proANP <120 pg/mL
    • Recommended upon presentation in patients who are suspected to have heart failure, especially when the diagnosis is uncertain, also to exclude other causes of dyspnea
    • May be utilized to establish prognosis of heart failure on admission and predischarge  
    • May also be used to screen individuals at risk of developing heart failure 
  • Exercise testing
    • Allows objective evaluation of exertional symptoms and exercise capacity
    • To detect the presence of reversible ischemia
    • Aids in the evaluation of patients for mechanical circulatory support
  • Endomyocardial biopsy
    • May be used in patients with rapidly progressive clinical heart failure or ventricular dysfunction despite appropriate medical treatment and those who are suspected of having myocarditis or infiltrative diseases


  • Chest radiography
    • To rule out other non-cardiac causes of dyspnea and to evaluate heart size, presence of congestion, pulmonary or other diseases, and proper placement of implanted cardiac devices
      • Specific findings for acute heart failure (HF) include cardiomegaly, pulmonary venous congestion, pleural effusion and interstitial or alveolar edema
  • Echocardiography
    • Method of choice in patients with suspected heart failure because of its accuracy, availability, safety, and cost
      • Consider doing within 48 hours of admission for early management guidance if patient is hemodynamically unstable and after stabilization particularly with de novo disease; performed immediately in patients with suspected cardiogenic shock
    • To determine cardiac structure and function
    • May be performed if natriuretic peptide levels are elevated to rule out cardiac abnormalities
  • Coronary angiography
    • To evaluate the coronary anatomy
    • Recommended in patients with angina pectoris and patients with cardiogenic shock who are suitable for coronary revascularization
  • Cardiac catheterization
    • To evaluate patients for heart transplantation or mechanical circulatory support
    • To assess right and left heart function and pulmonary arterial resistance
  • Cardiac magnetic resonance (CMR) imaging
    • To evaluate cardiac structure and function
    • To characterize cardiac tissue, especially in patients with inadequate echocardiographic images or inconclusive echocardiographic findings
  • Myocardial perfusion/ischemia imaging [eg echocardiography, CMR, single photon emission computed tomography (SPECT), or positron emission tomography (PET)]
    • Should be considered in patients who are suspected to have coronary artery disease (CAD) and who are suitable for coronary revascularization
    • To assess the presence of reversible myocardial ischemia and viable myocardium
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