Chronic heart failure: treatment goals and diuretics
THE CONTEXT
Treatment aims to improve cardiac performance, relieve congestion and manage cardiac rate and rhythm through drugs, devices and selected interventions.
Treatment goals and approaches
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Improve myocardial contractility and coordination, optimise preload, decrease afterload, and control cardiac rate and rhythm.
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Available approaches include drug treatment, implantable devices and coronary revascularisation. Resistant cases may require mechanical assist devices or cardiac transplantation.
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Education of patients and relatives about causes and treatment can improve adherence. Some patients need daily weighing to assess fluid load and guide adjustment of diuretic therapy.
Choosing treatment by haemodynamic problem
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Preload-reducing drugs are appropriate when pulmonary or systemic venous congestion is present.
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Drugs that reduce afterload or increase myocardial contractility are more useful when symptoms and signs indicate low cardiac output.
Diuretic effects and excessive diuresis
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Diuretics increase urinary sodium and water excretion, reducing plasma volume and preload and improving pulmonary and systemic venous congestion.
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They may also reduce afterload and ventricular volume, lowering ventricular wall tension and increasing cardiac efficiency.
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Although reduced preload normally lowers cardiac output, patients with heart failure are beyond the apex of the Starling curve. Filling pressure may therefore fall substantially while cardiac output remains unchanged or improves.
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Over-diuresis can cause excessive volume depletion, reduced cardiac output, hypotension, lethargy and renal failure. This is especially likely when heart failure has a marked diastolic component.