Chapter

Clinical features and medical treatments

Martin R. Cowie and Badrinath Chandrasekaran

in Oxford Textbook of Medicine

Fifth edition

Published on behalf of Oxford University Press

Published in print May 2010 | ISBN: 9780199204854
Published online May 2011 | e-ISBN: 9780199570973 | DOI: http://dx.doi.org/10.1093/med/9780199204854.003.160501_update_001

Series: Oxford Textbooks

Clinical features and medical treatments

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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 patients—particularly elderly people—have no obvious valvular or systolic impairment of the heart and are assumed to have diastolic abnormalities.

Clinical features and diagnosis—heart 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 measures—few recommendations are supported by a large evidence base, but those that are widely advised include salt restriction (with a maximum daily intake of 6 g), smoking cessation, and supervised exercise training.

Drug therapy—most of the evidence base for the management of heart failure relates to heart failure due to LV systolic dysfunction—‘systolic heart failure’; the best management for heart failure due to valvular disease or diastolic heart failure is less clear. Relating to particular drugs (1) diuretics—these are the most effective means of removing retained fluid, and their introduction often produces rapid symptomatic relief; (2) angiotensin-converting enzyme (ACE) inhibitors—in 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) β-blockers—reduce the relative risk of death by about 25% and reduce the risk of death from heart failure by 35%; (5) spironolactone—reduces 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 β-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 resynchronization—up 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 life—palliative care skills are an important component of good management of heart failure.

Chapter.  10718 words.  Illustrated.

Subjects: Cardiovascular Medicine

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