It can be difficult to diagnose chronic heart failure because the symptoms and signs are often difficult to elicit and are often found in other common conditions.

• Suspect chronic heart failure if the person has typical symptoms and signs of heart failure, and risk factors in their medical or social history.
• Symptoms
• Breathlessness — on exertion (or at rest if the person has severe heart failure), on lying flat (orthopnea), or waking from sleep (paroxysmal nocturnal dyspnoea).
• Fatigue (tiredness, exhaustion, decreased exercise tolerance — due to a combination of breathlessness and fatigue).
• Fluid retention (ankle swelling, abdominal swelling).
• Signs
• Laterally displaced apex beat.
• Raised jugular venous pressure.
• Enlarged liver (due to engorgement).
• Third or fourth heart sound (gallop rhythm).
• Tachycardia.
• Lung crackles (persisting after coughing).
• Dependent oedema (legs, sacrum).
• Medical and social history
• Myocardial infarction, coronary artery disease, or angina.
• Atrial fibrillation.
• Diabetes mellitus.
• Hypertension.
• Excessive alcohol consumption.
• Cardiotoxic chemotherapy in the past.
• Family history of heart failure or sudden cardiac death from cardiomyopathy at a young age.

The information on when to suspect heart failure is based on the National Institute for Health and Clinical Excellence (NICE) guideline Chronic heart failure: national clinical guideline for diagnosis and management in primary and secondary care [National Clinical Guideline Centre for Acute and Chronic Conditions, 2010] and guidelines of the European Society of Cardiology [European Society of Cardiology, 2008].

Symptoms, signs, and medical history for diagnosing heart failure

• There is evidence that diagnostically useful information is provided by overall clinical impression; breathlessness; dependent oedema; third or fourth heart sounds; abdominojugular reflux; jugular venous distention; pulmonary crackles; and history of myocardial infarction, coronary artery disease, hypertension, diabetes mellitus, and dyslipidaemia. The findings that are most specific for heart failure are third heart sound (gallop rhythm) and elevated jugular venous pressure. The precision of clinical findings associated with heart failure varies greatly.

• If heart failure is suspected on the basis of the person's symptoms and signs and medical history (such as previous myocardial infarction [MI]):
• If the person has not had a previous MI, measure their natriuretic peptide level (availability may vary according to locality) — either B-type natriuretic peptide (BNP) or N-terminal pro-BNP.
• If the person has had an MI in the past, do not measure their natriuretic peptide level, as referral for specialist assessment and echocardiography is indicated regardless of natriuretic peptide levels.
• In all people, do 12-lead electrocardiography. In addition, consider other tests to evaluate for possible aggravating factors and to exclude other conditions with similar presentations:
• Chest X-ray.
• Blood tests: urea and electrolytes, creatinine, full blood count, thyroid function, liver function, glucose, lipids.
• Urinalysis.
• Lung function tests (peak flow or spirometry).
• Assess for and manage any underlying causes (where appropriate).

These recommendations reflect those made by the National Institute for Health and Clinical Excellence (NICE) in their guideline Chronic heart failure: national clinical guideline for diagnosis and management in primary and secondary care [National Clinical Guideline Centre for Acute and Chronic Conditions, 2010], as well as guidelines from the Scottish Intercollegiate Guidelines Network (SIGN) [SIGN, 2007] and European specialist society guidelines [European Society of Cardiology, 2008].

Electrocardiography (ECG)

• There is evidence that ECG can provide diagnostically useful information, such as presence of atrial fibrillation, new T-wave changes, ST-segment elevation or depression, pathological Q-waves, left bundle-branch block, and left ventricular hypertrophy. In particular, a normal ECG has reasonable negative predictive value for heart failure. A recent Health Technology Appraisal found that a completely normal ECG can help to rule out the diagnosis of heart failure, but the presence of any abnormality does not help to rule in the diagnosis of heart failure [Mant et al, 2009].

Chest X-ray

• There is evidence from systematic reviews that chest X-ray can provide diagnostically useful information, such as the presence of pulmonary venous congestion, interstitial oedema, alveolar oedema, cardiomegaly, and pleural effusion, but most of the studies included in the systematic reviews were conducted in hospital, where people were likely to be more severely ill than people managed in primary care. A recently published Health Technology Assessment found that an abnormal chest X-ray is moderately helpful for ruling the diagnosis in, but a normal chest X-ray cannot rule out the diagnosis (moderately specific but poorly sensitive).

Natriuretic peptides

• Measurement of natriuretic peptide levels helps to determine:
• The likelihood of the presence of heart failure.
• The need for referral for specialist assessment and confirmation of the diagnosis by echocardiography.
• The urgency of the referral.
• Two types of natriuretic peptide can be measured: B-type natriuretic peptide (BNP) and N-terminal pro-BNP (NT-proBNP). NT-proBNP is the inactive prohormone of BNP and is secreted from the ventricles in response to volume expansion and pressure overload (as occurs in heart failure). BNP increases renal excretion of sodium (natriuresis) and water (diuresis) and relaxes vascular smooth muscle, which leads to vasodilation.
• Increased levels of BNP or NT-proBNP are not on their own diagnostic of heart failure, because levels may be raised in people with left ventricular hypertrophy, myocardial ischaemia, atrial fibrillation, pulmonary hypertension, hypoxia, pulmonary embolism, right ventricular strain, chronic obstructive pulmonary disease, liver failure, sepsis, diabetes, and renal impairment. In addition, levels tend to be higher in people older than 70 years of age and in women.
• Levels are lower in people who are obese or are taking drug treatments, such as aldosterone antagonists, angiotensin-converting enzyme inhibitors, angiotensin-II receptor antagonists, beta-blockers, and diuretics.
• Good evidence supports the use of BNP and NT-proBNP tests in excluding heart failure. NICE found evidence from a Health Technology Assessment that although elevated levels of BNP and NT-proBNP do not confirm the diagnosis of heart failure, normal levels rule the diagnosis out (BNP and NT-proBNP are highly sensitive but have varying specificity). In addition, the accuracy of both tests was found to be similar, and BNP had greater diagnostic accuracy than ECG.
• NICE recommends that measurement of natriuretic peptide is not necessary in people with suspected heart failure and previous myocardial infarction — all such people require urgent referral (to be seen within 2 weeks) for echocardiography and specialist assessment, because if heart failure is present their prognosis is poor.

Diagnostic strategy

• CKS found no evidence on how best to sequence diagnostic tests. CKS recommendations reflect the guidelines published by NICE [National Clinical Guideline Centre for Acute and Chronic Conditions, 2010] and other organizations [SIGN, 2007; European Society of Cardiology, 2008]. The recommendations on diagnostic strategy are based on expert opinion within these guideline development groups.

A number of conditions can present with symptoms and signs similar to those of heart failure. These conditions can be grouped according to whether their most prominent feature is shortness of breath or peripheral oedema.

• Conditions causing shortness of breath
• Chest disease (lung, diaphragm, or chest wall), for example:
• Chronic obstructive pulmonary disease.
• Asthma.
• Pneumonia.
• Chronic pulmonary embolic disease.
• Cancer.
• Obesity.
• Volume overload from renal failure or nephrotic syndrome.
• Angina.
• Anxiety.
• Anaemia.
• Thyroid disease.
• Being unfit.
• Conditions causing peripheral oedema
• Dependent oedema that is not pathological, for example from prolonged inactivity.
• Nephrotic syndrome.
• Drugs (for example dihydropyridine calcium-channel blockers, nonsteroidal anti-inflammatory drugs).
• Hypoalbuminaemia (from renal or hepatic disease).
• Venous insufficiency.

This information is taken from the National Institute for Health and Clinical Excellence (NICE) guideline Chronic heart failure: national clinical guideline for diagnosis and management in primary and secondary care [National Clinical Guideline Centre for Acute and Chronic Conditions, 2010].

For people with suspected heart failure:

• Refer urgently (within 2 weeks) for specialist assessment and echocardiography:
• People who have had a previous myocardial infarction (MI).
• People without a history of MI who have high levels of natriuretic peptide — B-type natriuretic peptide (BNP) level above 400 pg/mL (116 pmol/L) or N-terminal pro-B-type natriuretic peptide (NT-proBNP) level above 2000 pg/mL (236 pmol/L).
• People with severe symptoms (if admission is not indicated).
• Women who are pregnant.
• Refer within 6 weeks:
• People without a history of MI who have a BNP level between 100–400 pg/mL (29-116 pmol/L) or an NT-proBNP level between 400–2000 pg/mL (47–236 pmol/L).
• If natriuretic peptide levels are normal (BNP level less than 100 pg/mL [29 pmol/L] or NT-proBNP less than 400 pg/mL [47 pmol/L]), a diagnosis of heart failure is unlikely. However, referral may still be needed if:
• Clinical suspicion of heart failure persists and the person is obese or taking drugs which lower natriuretic peptide levels (diuretics, angiotensin-converting enzyme inhibitors, angiotensin-II receptor antagonists, beta-blockers, or aldosterone antagonists).
• Another condition is suspected, which requires referral to a specialist.
• If it is not possible to measure natriuretic peptide levels, refer if:
• The electrocardiogram (ECG) is abnormal.
• The ECG is normal, but there is still a strong suspicion of heart failure.

These recommendations reflect those made by the National Institute for Health and Clinical Excellence (NICE) in their guideline Chronic heart failure: national clinical guideline for diagnosis and management in primary and secondary care [National Clinical Guideline Centre for Acute and Chronic Conditions, 2010], as well as guidelines from the Scottish Intercollegiate Guidelines Network [SIGN, 2007] and are consistent with recommendations in European specialist society guidelines [European Society of Cardiology, 2008].

Specialist

• NICE defines the term 'specialist' as a physician with sub-speciality interest in heart failure (often a consultant cardiologist) who leads a specialist multidisciplinary heart failure team of professionals with appropriate competencies from primary and secondary care. The team will involve, where necessary, other services (such as rehabilitation, tertiary care, and palliative care) in the care of individual persons.

Echocardiography

• Echocardiography can exclude significant valve disease, assess systolic and diastolic function, and detect intracardiac shunts.
• The most important measure of ventricular function provided by echocardiography in people with heart failure is left ventricular ejection fraction (LVEF).
• Cut-off values vary, but an LVEF of 45–50% or greater is usually considered to be normal.
• In most people with heart failure, left ventricular systolic function will be impaired and LVEF will be reduced.
• In people with preserved ejection fraction, echocardiography shows normal or only mildly abnormal left ventricular systolic function (LVEF >= 45–50%), and there may be evidence of diastolic dysfunction (abnormal left ventricular relaxation or diastolic stiffness) [European Society of Cardiology, 2008].

Referral

• NICE recommends referral for specialist assessment for confirmation of the diagnosis, because the diagnosis should not be based on the results of echocardiography alone and it is important to identify the type and severity of the abnormality responsible for heart failure.
• NICE recommends urgent referral (within 2 weeks) for people with high natriuretic peptide levels or who have had a myocardial infarction, because they have a worse prognosis (high chance of mortality) and a high probability of having heart failure.
• Good evidence supports the use of B-type natriuretic peptide or N-terminal pro-B-type natriuretic peptide tests to exclude heart failure; normal levels make a diagnosis of heart failure unlikely. However, natriuretic peptide levels can be reduced by obesity or certain drug treatments (aldosterone antagonists, angiotensin-converting enzyme inhibitors, angiotensin-II receptor antagonists, beta-blockers, and diuretics), and this should be considered when interpreting values.
• The availability of tests for natriuretic peptide vary from area to area. It was estimated that in 2008, only one third of primary care trusts had access to natriuretic peptide testing, although it is thought that this number has increased [British Heart Foundation, 2008b]. CKS recommends that when heart failure is suspected and it is not possible to measure natriuretic peptide levels, use the results from electrocardiography (ECG) to decide whether to refer the person for specialist assessment and echocardiography. A normal ECG can help to rule out the diagnosis of heart failure [Mant et al, 2009]. However, if the ECG is normal and there is still a strong clinical suspicion of heart failure, CKS recommends that specialist assessment should be considered (about 1 in 10 people with heart failure have a normal ECG [European Society of Cardiology, 2008]).

• If possible, stop any drugs that may affect the person's heart failure, such as nonsteroidal anti-inflammatory drugs (including those bought over the counter) or calcium-channel blockers.
• If symptoms are sufficiently severe to warrant treatment (but not admission), start a loop diuretic:
• Furosemide 20 mg/day to 40 mg/day.
• Bumetanide 0.5 mg/day to 1.0 mg/day.
• Torasemide 5 mg/day to 10 mg/day.
• If higher doses are required to relieve the person's symptoms adequately, check adherence to treatment, review the differential diagnosis, and seek specialist advice.
• Seek specialist advise for pregnant women before initiating any drug treatments.

These recommendations are based on guidelines published by the National Institute for Health and Clinical Excellence (NICE) [National Clinical Guideline Centre for Acute and Chronic Conditions, 2010], on a guideline published by the the European Society of Cardiology [European Society of Cardiology, 2008], and CKS expert reviewers.

Loop diuretics

• Usually, diuretics rapidly improve symptoms (breathlessness) and exercise performance in people with heart failure by reducing fluid overload. Most people with heart failure are treated with loop diuretics rather than thiazides, because loop diuretics are more powerful at inducing diuresis and natriuresis [National Clinical Guideline Centre for Acute and Chronic Conditions, 2010].
• It is common practice to initiate diuretics at low doses, and to increase the dose as required to control symptoms of fluid overload [National Clinical Guideline Centre for Acute and Chronic Conditions, 2010].
• If a person is suspected to have heart failure and needs symptomatic treatment while waiting to see a specialist, CKS recommends use of a loop diuretic. However, CKS recommends that specialist advice be sought if doses higher than furosemide 40 mg (or equivalent) are thought to be necessary because:
• The diagnosis may not be correct (particularly if the person is responding poorly to a diuretic).
• High doses of loop diuretic (furosemide 80 mg or equivalent) may cause subsequent difficulties if an angiotensin-converting enzyme inhibitor needs to be started. First-dose hypotension (with dizziness or fainting) is more likely to occur in people taking diuretics, particularly if the dose of diuretic is high [Clementy et al, 1986].
• In addition, high doses of diuretic may result in hypokalaemia and other electrolyte disturbances, and renal impairment and acute renal failure have been reported [Glück et al, 1984; Clementy et al, 1986; De Lepeleire et al, 1988].
• CKS expert reviewers agreed that the dose of a loop diuretic should not exceed furosemide 40 mg (or equivalent) for the management of suspected heart failure, unless on specialist advice.

Specialist

• NICE defines the term 'specialist' as a physician with sub-speciality interest in heart failure (often a consultant cardiologist) who leads a specialist multidisciplinary heart failure team of professionals with appropriate competencies from primary and secondary care. The team will involve, where necessary, other services (such as rehabilitation, tertiary care, and palliative care) in the care of individual persons.

For information on contraindications, cautions, drug interactions, and adverse effects, see the electronic Medicines Compendium (eMC) (http://emc.medicines.org.uk), or the British National Formulary (BNF) (www.bnf.org).