The syndrome of cardiac cachexia

Abstract

Cachexia, i.e. body wasting, has long been recognised as a serious complication of chronic illness. The occurrence of wasting in chronic heart failure (CHF) has been known for many centuries, but it has not been investigated extensively until recently. Cardiac cachexia is a common complication of CHF which is associated with poor prognosis, independently of functional disease severity, age, measures of exercise capacity, and left ventricular ejection fraction. Patients with cardiac cachexia suffer from generalised loss of lean tissue, fat tissue, as well as bone tissue. Cachectic CHF patients are weaker and fatigue earlier. This is due to both reduced skeletal muscle mass and impaired skeletal muscle quality. Concerning the pathophysiology of cardiac cachexia, there is increasing evidence that neurohormonal and immune abnormalities may play a crucial role. Cachectic CHF patients have raised plasma levels of norepinephrine, epinephrine, and cortisol, and they show high plasma renin activity and increased plasma aldosterone levels. A number of studies have also shown that cardiac cachexia is linked to raised plasma levels of inflammatory cytokines, such as tumor necrosis factor alpha. The available evidence suggests that cardiac cachexia is a multifactorial neuroendocrine and metabolic disorder with a poor prognosis. A complex imbalance of different body systems, termed catabolic/anabolic imbalance, is likely to be responsible for the development of the wasting process. It is hoped that a better understanding of the pathophysiological mechanisms involved in cardiac cachexia will lead to novel therapeutic strategies in the (near) future.