Patent ID: 8219213

Claim:
An implantable medical lead comprising: a distal tip; an elongated body coupled to the distal tip, the elongated body comprising a lumen therethrough and an attachment window proximate the distal tip that exposes a portion of the lumen, wherein the attachment window comprises a proximal end and a distal end and extends partially, but not fully, around an outer surface of the elongated body, between the proximal end and the distal end of the attachment window; an elongated lead element carried within the lumen; and a rotatable fixation helix carried within the lumen proximate the attachment window, the fixation helix having a proximal end coupled to the lead element and a tip at a distal end for engaging an implant site proximate the attachment window, and wherein the fixation helix rotates to advance the distal end of the fixation helix towards the distal end of the attachment window, and wherein the fixation helix is movable between a retracted position and an extended position past which the fixation helix cannot be advanced, and wherein a portion of the distal end of the fixation helix is retained within the elongated body when the fixation helix is in the extended position.