An apparatus for treating tissue, comprising a sheath defining a lumen sized and shaped to receive a treatment device therein, a guide member coupled to the sheath and extending a predetermined distance substantially parallel to a longitudinal axis of the sheath, and a stabilizer element for engaging an anchoring device coupled to tissue to stabilize the sheath and the treatment device, the stabilizing element being movably coupled to the guide member for movement therealong substantially parallel to the longitudinal axis of the sheath wherein, when in a proximal-most position, the stabilizer element is located proximally of a proximal end of the guide member.