A catheter device for repair of the heart by implanting an artificial chordae line, the catheter device comprising: a leaflet anchor for placement in a leaflet of a heart valve, wherein the leaflet anchor is arranged to be coupled to the artificial chordae line; and a leaflet anchor deployment mechanism for deploying the leaflet anchor to attach it to the leaflet of the heart, wherein the leaflet anchor deployment mechanism comprises a mechanical gripper device for grasping the leaflet of the heart valve, wherein the gripper device comprises a leaflet anchor tube for housing the leaflet anchor in a folded configuration; the gripper device and leaflet anchor being arranged such that when, in use, the gripper device grasps the leaflet, the leaflet anchor can be pushed out of the leaflet anchor tube to pierce the leaflet and form the leaflet anchor into an unfolded configuration so that hooked formations of the leaflet anchor can, in use, secure the leaflet anchor in the leaflet; wherein the mechanical gripper device includes a first gripper arm rotatably coupled to a main body of the catheter device so that the first gripper arm can rotate relative to the catheter device to move an outer end of the first gripper arm away from the main body of the catheter device; characterised in that: the mechanical gripper device further includes a second gripper arm rotatably and/or slideably coupled to the main body of the catheter device so that the second gripper arm can rotate and/or slide relative to the main body of the catheter device to move an outer end of the second gripper arm away from the main body of the catheter device; wherein the first and second gripper arms (30, 32) are arranged so that they can move to come into contact with one another at a point spaced apart from the main body of the catheter device. a leaflet anchor for placement in a leaflet of a heart valve, wherein the leaflet anchor is arranged to be coupled to the artificial chordae line; and a leaflet anchor deployment mechanism for deploying the leaflet anchor to attach it to the leaflet of the heart, wherein the leaflet anchor deployment mechanism comprises a mechanical gripper device for grasping the leaflet of the heart valve, wherein the gripper device comprises a leaflet anchor tube for housing the leaflet anchor in a folded configuration; the gripper device and leaflet anchor being arranged such that when, in use, the gripper device grasps the leaflet, the leaflet anchor can be pushed out of the leaflet anchor tube to pierce the leaflet and form the leaflet anchor into an unfolded configuration so that hooked formations of the leaflet anchor can, in use, secure the leaflet anchor in the leaflet; wherein the mechanical gripper device includes a first gripper arm rotatably coupled to a main body of the catheter device so that the first gripper arm can rotate relative to the catheter device to move an outer end of the first gripper arm away from the main body of the catheter device; characterised in that: the mechanical gripper device further includes a second gripper arm rotatably and/or slideably coupled to the main body of the catheter device so that the second gripper arm can rotate and/or slide relative to the main body of the catheter device to move an outer end of the second gripper arm away from the main body of the catheter device; wherein the first and second gripper arms (30, 32) are arranged so that they can move to come into contact with one another at a point spaced apart from the main body of the catheter device. the mechanical gripper device further includes a second gripper arm rotatably and/or slideably coupled to the main body of the catheter device so that the second gripper arm can rotate and/or slide relative to the main body of the catheter device to move an outer end of the second gripper arm away from the main body of the catheter device; wherein the first and second gripper arms (30, 32) are arranged so that they can move to come into contact with one another at a point spaced apart from the main body of the catheter device.