PERIPHERAL FACTORS IN THE MANAGEMENT OF CONGESTIVE-HEART-FAILURE

Maladaptive changes in the periphery largely account for the symptomatology of patients with congestive heart failure (CHF). A decline in the systolic function of the left ventricle precipitates activation of neural and humoral systems to provide circulatory support. These include sympathetic release of norepinephrine, increases in angiotensin II, elevated levels of circulating arginine vasopressin, and impairment of the counterregulatory function of atrial natriuretic peptide. The resultant circulatory changes are ultimately responsible for the declining function of the peripheral vasculature and skeletal muscles of patients with CHF. In the peripheral vasculature, impaired vasodilatory capacity results from excess vessel wall stiffness, endothelial dysfunction, and structural abnormalities. The skeletal muscles develop poor aerobic capacity as a result of a change in predominant fiber type and excess reliance on glycolytic metabolic pathways. Physical deconditioning induced by symptoms tends to further promote these peripheral changes. Therapeutic interventions with symptomatic and prognostic benefits have essentially been targeted at the periphery. Angiotensin converting enzyme inhibitors may act by normalizing electrolyte and water balance, improving vascular endothelial function, and reversing structural changes in peripheral vessels. Exercise training appears to exert its benefit at the level of the vascular endothelium. Advances in the therapy of CHF depend on a greater understanding of changes in the periphery.