Metabolic control of the circulation: implications for congestive heart failure

The role of metabolic processes in the control of the normal circulation will be discussed with particular emphasis on how metabolic events, particularly those that occur with the performance of exercise, result in production of vasoactive substances and sympathetic activation. Heart failure patients will have altered metabolism, particularly in skeletal muscle, that may result in a lesser degree of peripheral vasodilation and will also have an abnormal response to sympathetic stimuli, with less cardiac stimulation but preserved peripheral vasoconstriction. The consequences of these abnormalities on the hemodynamics and metabolic processes that occur with exercise in the heart failure patient will be discussed in detail. The effect of therapeutic interventions such as drug therapy and exercise training will be reviewed.