USE OF IVABRADINE, OR 3-{3-[{[(7S)-3,4-DIMETHOXYBICYCLO[4.2.0]OCTA-1,3,5-TRIEN-7-YL]- METHYL}-(METHYL)-AMINO]-PROPYL}-7,8-DIMETHOXY-1,3,4,5-TETRAHYDRO-2H-3-BENZAZEPIN-2-ONE, ITS ADDITION SALTS WITH A PHARMACEUTICALLY ACCEPTABLE ACID AND THEIR HYDRATES, FOR OBTAINING A MEDICAMENT INTENDED FOR THE TREATMENT OF ENDOTHELIAL DYSFUNCTION.