Investigations

Possible investigations in possible heart failure include:

• chest radiology
  
  
• the ECG - is recommended in every patient with suspected HF (1), may elucidate the cause of heart failure:
  • left ventricular hypertrophy which may be caused by chronic hypertension or aortic stenosis
  • evidence of ischaemic heart disease
  • p-mitrale of mitral stenosis
    
    
• echocardiography identifies:
  • focal or diffuse myocardial dysfunction
  • valvular disease
  • pericardial disease
  • left ventricular systolic dysfunction
    
    
• biochemistry, haematology and urinalysis:
  • defines electrolyte disturbances and assesses renal function
  • excludes anaemia
  • exclude thyrotoxicosis in patients with atrial fibrillation
  • excludes causes of oedema such as liver disease, nephrotic syndrome and acute renal failure
  • natriuretic peptides - testing for Brain-type natriuretic peptide (BNP), atrial natriuretic peptide (ANP), and N-terminal (NT)-ANP has been shown to increase the reliability of diagnosis of heart failure in primary care
    • these peptides are released from ventricular myocytes in response to volume overload (stretch), and their concentration has been shown to an extremely sensitive marker for heart failure
      
      
• Other possible investigations include:
  • radionuclide ventriculography e.g. MUGA scan
  • a myocardial biopsy to obtain histological data

NICE have suggested that investigations chosen in primary care depend on whether there is a past history of myocardial infarction. NICE suggest to (1):

• refer patients with suspected heart failure and previous myocardial infarction (MI) urgently, to have transthoracic Doppler 2D echocardiography and specialist assessment within 2 weeks
  
  
• measure serum natriuretic peptides (B-type natriuretic peptide [BNP] or N-terminal pro-B-type natriuretic peptide [NTproBNP]) in patients with suspected heart failure without previous MI
  
  
• because very high levels of serum natriuretic peptides carry a poor prognosis, refer patients with suspected heart failure and a BNP level above 400 pg/ml (116 pmol/litre) or an NTproBNP level above 2000 pg/ml (236 pmol/litre) urgently, to have transthoracic Doppler 2D echocardiography and specialist assessment within 2 weeks
  
  
• refer patients with suspected heart failure and a BNP level between 100 and 400 pg/ml (29-116 pmol/litre) or an NTproBNP level between 400 and 2000 pg/ml (47-236 pmol/litre) to have transthoracic Doppler 2D echocardiography and specialist assessment within 6 weeks Perform an ECG in all patients and consider the following tests to evaluate possible aggravating factors and/or alternative diagnoses: When a diagnosis of heart failure has been made, assess severity, aetiology, precipitating factors, type of cardiac dysfunction and correctable causes
  • chest X-ray
  • blood tests:
    • electrolytes, urea and creatinine - eGFR (estimated glomerular filtration rate)
    • thyroid function tests
    • liver function tests
    • fasting lipids
    • fasting glucose
    • full blood count
    • urinalysis
    • peak flow or spirometry

Notes:

• serum natriuretic peptides:
  • obesity or treatment with diuretics, angiotensin-converting enzyme (ACE) inhibitors, beta-blockers, angiotensin II receptor antagonists (ARBs) and aldosterone antagonists can reduce levels of serum natriuretic peptides
    
    
  • high levels of serum natriuretic peptides can have causes other than heart failure (for example, left ventricular hypertrophy, ischaemia, tachycardia, right ventricular overload, hypoxaemia [including pulmonary embolism], renal dysfunction [GFR < 60 ml/minute], sepsis, chronic obstructive pulmonary disease [COPD], diabetes, age > 70 years and cirrhosis of the liver)
    
    
  • a serum BNP level less than 100 pg/ml (29 pmol/litre) or an NTproBNP level less than 400 pg/ml (47 pmol/litre) in an untreated patient makes a diagnosis of heart failure unlikely
    
    
  • the level of serum natriuretic peptide does not differentiate between heart failure due to left ventricular systolic dysfunction and heart failure with preserved left ventricular ejection fraction

Reference:

• 1) NICE (August 2010). chronic heart failure
• 2) MeReC Bulletin 2008; 18 (3):1-9.