The incidence of
congestive heart failure (CHF) is increasing in Westernized countries, and patients with CHF experience poor quality of life (functional impairment, high hospitalization rate and high mortality).
Malnutrition occurring during the course of CHF is referred to as cardiac
cachexia and is associated with higher mortality independent of the severity of CHF. Cardiac
cachexia involving a loss of more than 10% of lean body mass can clinically be defined as a bodyweight loss of 7.5% of previous dry bodyweight in a period longer than 6 months. The energy requirements of patients with CHF, whether cachectic or not, are not noticeably modified since the increase in resting energy expenditure is compensated by a decrease in physical activity energy expenditure.
Malnutrition in CHF has been ascribed to neurohormonal alterations, i.e. anabolic/catabolic imbalance and increased
cytokine release.
Anorexia may occur, particularly during acute decompensation of CHF. Function is impaired in CHF, because of exertional
dyspnea and changes in skeletal muscle. Decreased exercise endurance seems to be related to decreased mitochondrial oxidative capacities and
atrophy of type 1 fibers, which are attributed to alteration in muscle perfusion and are partially reversible by training.
Malnutrition could also impair muscle function, because of decreased muscle mass and strength associated with decreased glycolytic capacities and
atrophy of type 2a and 2b fibres. With respect to the putative mechanisms of cardiac
cachexia, anabolic
therapy (
hormones or nutrients) and anticytokine
therapy have been proposed, but trials are scarce and often inconclusive. In surgical patients with CHF, perioperative (pre- and postoperative)
nutritional support has been shown to be effective in reducing the mortality rate. Long term nutritional supplementation trials in patients with CHF and
cachexia are thus required to establish recommendations for the nutritional management of patients with CHF.