Medical devices (20), systems and related methods for delivering a tissue anchor(26). One embodiment of such a medical device generally comprises a needle (22)and a sheath (24) that assist in retaining the tissue anchor, connected to a suture(40) at the distal end (42) of the needle during manipulation of the medical device.The needle has a needle lumen (32) sized to slidably receive the tissue anchor.The sheath has a sheath lumen (44) sized to slidably receive the needle. A distalend of the sheath defines a sheath slot (48) sized to receive the suture (40) therein.The medical systems include one or more tissue anchors in conjunction with oneof the medical devices.