The aim of this study is to evaluate whether isovolumic relaxation flow propagation velocity (IRFPV), a newly proposed relaxation parameter, is independent of load alterations. Thirty-nine uremic patients (21 men; age 62 +/- 10 y) who underwent echocardiography 1 h before and 1 h after hemodialysis (HD) were included. After HD, body weight, systolic blood pressure, early transmitral filling wave velocity (E), early diastolic mitral annular velocity (Ea) and early diastolic inflow propagation velocity (EPV) decreased significantly (p <or= 0.007), while IRFPV kept constant (p = 0.550). A subgroup analysis showed that in patients with body weight reduction <2.5 kg, E (p = 0.005) decreased significantly, but Ea (p = 0.078), EPV (p = 0.155) and IRFPV (p = 0.324) did not change after HD. In patients with body weight reduction >or=2.5 kg, E (p < 0.001), Ea (p = 0.001) and EPV (p = 0.001) decreased significantly but IRFPV (p = 0.715) was still constant after HD. In conclusion, IRFPV may be a load-independent parameter in assessing left ventricular diastolic function. However, Ea and EPV are load-independent only at minor load alterations. In evaluating left ventricular diastolic function in HD patients whose loading conditions frequently vary with time, IRFPV seems to be more adequate than Ea and EPV.