Arterial compliance (AC) is expected to play a major role on cardiac efficacy by acute or long-term mechanisms. The aim of this study was to investigate the purely mechanical effect of AC on left ventricular (LV) performance, for different conditions of LV dysfunction (systolic versus diastolic). A hydraulic, Windkessel model of systemic circulation was used. LV function and aortic flow were simulated using a left ventricular assist device (LVAD). Two cases of LV dysfunction were simulated: Case A, systolic and Case B, diastolic dysfunction. In Case A, AC increased from 1.14 to 2.85 ml mm Hg(-1) leading to an increase in LVAD stroke volume up to 6%, while no significant effect was observed in Case B. LVAD systolic work was decreased by 4% in systolic and by 11% in diastolic LVAD dysfunction. The purely mechanical effect of AC changes on LVAD function was different between systolic and diastolic dysfunction. It might be expected that even an acute reduction in arterial stiffness could enhance LV performance by different means in systolic compared to diastolic dysfunction.