The effects of congestive heart failure and aging on arterial vascular compliance were evaluated in 46 heart-failure patients and 48 healthy control subjects, over a 19-75-year age range. Compliance values were calculated from a modified Windkessel model of the peripheral vasculature, utilizing parameters from the pulse contour analysis of the brachial artery pressure waveform. Cardiac output was determined by thermodilution for the heart-failure patients and by dye dilution for the controls. The results show that distal vascular compliance (ml/mm Hg) is significantly lower (0.036 vs 0.0744, p < 0.001) in heart failure and systemic vacular resistance is higher (1594 vs 1381, p < 0.05), while proximal compliance is unchanged. Resistance increased and proximal and distal compliance decreased with increasing age in the controls, but only the decrease in proximal compliance is associated with increasing age in the heart-failure group.