The slope (Ees) of the left ventricular end- systolic pressure-volume relationships (ESPVR), preload recruitable stroke work (PRSW) and maximal slope of systolic pressure increment – end diastolic volume relation (+dP/dt-EDV) are shown in young adult, young treated with INO-1001, aging and aging treated with INO-1001 male rats. Values are mean ± s.e.mean of 7 experiments in each group. *, P<0.05 versus young control; #, P<0.05 versus aging control.