ObjectivesToexploretheeffectoflosartanoncardiacandrenalfunctioninpatientswithchronicheartfailure(CHF).MethodsSixty-fivepatientswithCHFwerepidedintotwogroupsusingarandomized,controlandsingleblindmethod:losartangroup(n=30)andconventiongroup(n=35),withatreatmentcourseof8weeksforbothgroups.TheconcentrationsofcystatinC(cysC)inserum,microamountalbumin(MA)inurineweremeasuredbyimmunoturbidimetry.Theconcentrationofaquaporin-2(AQP-2)wasdeterminedbyenzyme-linked-immunosorbentassay(ELISA)andtheheartcontractilefunctionwasmeasuredbyechocardiographybeforeandaftertreatmentrespectively.ResultsComparingwithroutinetreatmentgroup,leftventricularend-diastolicdimension(LVEDd)decreasedsignificantly,whileleftventricularejectionfraction(LVEF)andleftventricularfractionalshortening(LVFS)increasedsignificantlyinlosartangroup.ThelevelsofcysCinserumandMA,AQP-2inurineweresignificantlylowerinlosartangroupthaninroutinetreatmentgroup.ConclusionLosartancanimprovecardiacandrenalfunctioninpatientswithCHF.