16.5.1 Heart failure Clinical features and medical treatments Updated on 25 May 2011 Recommendations for diagnosis and treatment of heart failure altered to reflect modifications of the UK National Institute of Health and Clinical Excellence (NICE) clinical guideline, which was updated in 2010. Enhanced discussion of brain natriuretic peptides in diagnosis, and of the use of eplerenone and cardiac resynchronization therapy in patients with mild heart failure.

Heart failure is a clinical syndrome that results from any structural or functional cardiac disorder that reduces the ability of the heart to function as a pump. It affects 1 to 2% of the population, and mortality may be as high as 30% in the year after diagnosis, falling to between 5 and 10% annually thereafter with best treatment. The most common underlying pathophysiological abnormality is systolic dysfunction of the left ventricle (LV), but a few patientsparticularly elderly peoplehave no obvious valvular or systolic impairment of the heart and are assumed to have diastolic abnormalities.Clinical features and diagnosisheart failure is usually associated with dyspnoea, fatigue, and fluid retention, but these are nonspecific, hence diagnosis depends on careful clinical examination supplemented by tests, in particular echocardiography. Measurement of the plasma concentration of B-type natriuretic peptide (BNP) is the best test for ruling out heart failure in a particular patient.

Management

Treatment usually involves lifestyle measures and drug therapy. Implantable devices, such as pacemakers and cardioverter-defibrillators, are being used increasingly, but surgical interventions only apply to a few patients.Lifestyle measuresfew recommendations are supported by a large evidence base, but those that are widely advised include salt restriction (with a maximum daily intake of 6g), smoking cessation, and supervised exercise training.

Drug therapymost of the evidence base for the management of heart failure relates to heart failure due to LV systolic dysfunctionsystolic heart failure; the best management for heart failure due to valvular disease or diastolic heart failure is less clear. Relating to particular drugs (1) diureticsthese are the most effective means of removing retained fluid, and their introduction often produces rapid symptomatic relief; (2) angiotensin-converting enzyme (ACE) inhibitorsin chronic heart failure these reduce the relative risk of death by 23% and of worsening heart failure by 35%; (3) angiotensin receptor blockers (ARBs)proven in randomized trials to reduce the risk of mortality and heart failure deterioration, and now generally used in patients who cannot tolerate an ACE inhibitor due to cough; (4) -blockersreduce the relative risk of death by about 25% and reduce the risk of death from heart failure by 35%; (5) spironolactonereduces the risk of death by 30% in patients with moderate to severe heart failure despite treatment with diuretic and ACE inhibitor; eplerenone is a more selective aldosterone antagonist that is often prescribed in place of spironolactone if gynaecomastia develops while on that drug. However, it is important to recognize that the treatment of patients with heart failure with diuretics and/or ACE inhibitors or ARBs and/or -blockers and/or spironolactone (or eplerenone) is often difficult, with problems arising from hypotension, bradycardia, hyperkalaemia, and deterioration of renal function. Close monitoring and careful clinical judgement are required.

Cardiac resynchronizationup to 20% of patients with heart failure have mechanical dyssynchrony due to native left bundle branch block, which means that the interventricular septum and lateral free wall of the LV do not contract at the same time, reducing the efficiency of pumping. An atriobiventricular pacing system, where conventional right atrial and right ventricular pacing wires are supplemented by a third lead placed in a lateral coronary vein via the coronary sinus to allow pacing of the LV system, can reduce the dyssynchrony (cardiac resynchronization therapy, CRT). Large clinical trials have demonstrated that this can produce a substantial reduction in mortality (up to 40%) in patients with left bundle branch block and moderate to severe symptoms of heart failure despite optimal drug therapy, and recent studies indicate that some patients with less severe disease can also benefit. The risk of sudden cardiac death can be further reduced by combining CRT with an implantable cardioverter defibrillator (ICD).

End of lifepalliative care skills are an important component of good management of heart failure.

Introduction

Heart failure is a clinical syndrome that results from any structural or functional cardiac disorder that reduces the ability of the heart to function as a pump. Any condition that damages the heart can lead to heart failure.Heart failure is not in itself a complete diagnosis, which requires consideration of the underlying abnormality of the heart, the severity of the syndrome, the aetiology, the precipitating and exacerbating factors, the identification of concomitant disease relevant to management, and an estimation of prognosis. The diagnosis has serious implications both for the patient and the health care system. Mortality may be as high as 30% in the year after diagnosis, but with optimal drug and device therapy drops to between 5 and 10% annually thereafter. In addition, heart failure impacts on quality of life more than almost any other chronic medical condition. Comorbiditysuch as renal dysfunction, cognitive impairment, and chronic airways diseaseis common and may complicate management.

Heart failure is common, affecting 1 to 2% of the population, with the average age at diagnosis being 75years. The management of heart failure accounts for 1 to 2% of the health care budget of most developed countries, largely due to the cost of the often lengthy hospitalizations required to restabilize the syndrome after deterioration.

Diagnosis is increasingly straightforward as a result of improvements in cardiac imaging and biochemical assays. Treatment has changed markedly in the past two decades through better understanding of the underlying pathophysiology and many large clinical trials of drug and devices. In a rapidly changing field, communication between health care professionals, education of patients and carers, and better chronic disease management remain key to improving patient outcomes.

Diagnosis

Heart failure is usually associated with dyspnoea, fatigue, and fluid retention. Other symptoms may include nocturia, anorexia, abdominal bloating and discomfort, constipation, and cerebral symptoms such as confusion, dizziness, and memory impairment. None of these symptoms is specific for heart failure, and several other conditions can present in the same way (Box 16.5.1). Symptoms alone cannot therefore be relied upon to make the diagnosis: good clinical skills with history taking and a careful physical examination need to be supplemented by further tests. Box 16.5.1 Other conditions that may present with symptoms similar to heart failure

Obesity

Chest diseaseincluding lung, pleura, diaphragm, or chest wall disease

Venous insufficiency in lower limbs

Drug-induced ankle swelling (e.g. amlodipine, nifedipine, felodipine)

Drug-induced fluid retention (e.g. steroids, NSAIDs)

Hypoalbuminaemia

Intrinsic renal or hepatic disease

Pulmonary embolic disease

Depression and/or anxiety

Severe anaemia

Severe thyroid disease

Bilateral renal artery stenosis

Useful tests in patients with suspected heart failureA patient with suspected heart failure should have the following investigations: 12-lead electrocardiogram (ECG)

Chest radiographprincipally to exclude other conditions such as lung cancer or pneumonia, but it may help confirm the diagnosis if it shows cardiomegaly and pulmonary congestion

Blood biochemistry (including urea, creatinine, glucose, electrolytes), haemoglobin, thyroid and liver function tests, and blood lipids

Serum natriuretic peptides (when available)

Urinalysis to detect proteinuria or glycosuria

Cardiac imagingusually a transthoracic echocardiogram, which can rapidly provide detailed information about the structure and function of the cardiac chambers, valves, and pericardium

The algorithm for the diagnosis of heart failure currently recommended by the National Institute for Health and Clinical Excellence (NICE) in the United Kingdom is shown in Fig. 16.5.1. Measurement of serum natriuretic peptides and echocardiography are recommended as the key diagnostic tests, with echocardiography being most generally available.

Fig. 16.5.1 Algorithm for diagnosis of heart failure, as recommended by NICE (2010).NICE CHF guideline.Algorithm for the diagnosis of heart failure. Normal serum natriuretic peptide levels are defined as brain natriuretic peptide (BNP) levels < 100 pg per mL (100 ng per L) or N-terminal pro-BNP levels < 400 pg per mL (400 ng per L). Raised serum natriuretic peptide levels are defined as BNP levels between 100 and 400 pg per mL (100 and 400 ng per L) or N-terminal pro-BNP levels between 400 and 2,000 pg per mL (400 and 2,000 ng per L). High serum natriuretic peptide levels are defined as BNP levels > 400 pg per mL or N-terminal pro-BNP levels > 2,000 pg per mL.

The tests listed above will not only help confirm the clinical diagnosis, but will also help exclude other pathologies that may masquerade as heart failure, such as respiratory conditions, severe anaemia, or renal disease. They may also identify comorbidities that can influence management. In most cases the investigations described will rapidly confirm the clinical diagnosis of heart failure, but some cases may be more difficult and the input of a specialist may be required.If the resting ECG is completely normal then heart failure due to left ventricular (LV) systolic dysfunction is unlikely. A better rule out test, when available, is measurement of the plasma concentration of B-type natriuretic peptide (BNP) or N-terminal pro-BNP (NT-proBNP). For patients with new symptoms, heart failure (whatever the cause) is unlikely if the BNP level is low (16s

Reoperation

White blood cell count >15 109/litre; pyrexia

Urine output