Heart failure precipitants and chronic clinical features
THE CONTEXT
Pre-existing heart disease can decompensate after an additional stress. Chronic heart failure commonly follows a relapsing and remitting course with stable periods and episodes that may require hospitalisation.
Precipitating or aggravating factors
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Myocardial ischaemia or infarction, intercurrent illness, arrhythmia—especially atrial fibrillation—and pulmonary embolism may precipitate or aggravate heart failure.
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Inappropriate reduction of therapy, administration of drugs with negative inotropic properties such as β-blockers, and fluid-retaining drugs such as non-steroidal anti-inflammatory drugs or glucocorticoids may aggravate heart failure.
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Pregnancy, thyrotoxicosis and anaemia increase metabolic demand and may precipitate deterioration. Intravenous fluid overload is another precipitant.
Blood is diverted away from skeletal muscle to maintain vital-organ perfusion, contributing to fatigue, weakness and loss of muscle mass.
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Poor renal perfusion causes oliguria and uraemia.
Congestion and oedema
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Left heart failure causes pulmonary oedema with dyspnoea and inspiratory crepitations over the lung bases.
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Right heart failure causes elevated jugular venous pressure, hepatic congestion and dependent peripheral oedema.
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Dependent oedema affects the lower legs in ambulant patients and the thighs and sacrum in bed-bound patients. Ascites or pleural effusion may also occur.
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Peripheral oedema has causes other than heart failure.
Cardiac cachexia
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Marked weight loss in chronic heart failure is termed cardiac cachexia.
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Contributors include anorexia and impaired absorption from gastrointestinal congestion, poor tissue perfusion from low cardiac output, and skeletal muscle atrophy from immobility.