a device for treatment of mitral annulus dilation is disclosed , wherein the device comprises two states . in a first of these states the device is insertable into the coronary sinus and has a shape of the coronary sinus . when positioned in the coronary sinus , the device is transferable to the second state assuming a reduced radius of curvature , whereby the radius of curvature of the coronary sinus and the radius of curvature as well as the circumference of the mitral annulus is reduced .