An annuloplasty device is disclosed for treating a defective mitral valve having an annulus, comprising a removable and flexible elongate displacement unit for temporary insertion into a coronary sinus (CS) adjacent the valve, wherein the displacement unit has a delivery state for delivery into the CS, and an activated state to which the displacement unit is temporarily and reversibly transferable from said delivery state, the displacement unit comprises a proximal reversibly expandable portion, a distal anchoring portion being movable in relation to the proximal expandable portion in a longitudinal direction of the displacement unit to said activated state in which the shape of the annulus is modified to a modified shape, wherein the proximal expandable portion is reversibly foldable to an expanded state for positioning against a tissue wall at the entrance of the CS, and wherein the distal anchoring portion comprises an inflatable unit.
