Congestive heart failure is characteristically associated with systemic vasoconstriction and impaired vasodilatory capacity, leading to decreased peripheral perfusion. Factors identified as possible causes of reduced vasodilatory capacity include activation of the sympathetic nervous system and the renin-angiotensin system, vascular stiffness due to increased sodium and fluid retention, and structural vascular changes. More recently, the role of the endothelium as a mediator of vasoregulation and tissue perfusion has been recognized.