Patent ID: 7801627

Claim:
A cardiac lead comprising: a lead body including a conductor, the lead body extending from a proximal end configured to be connected to a pulse generator to a distal end defining a cavity including a circumferential lip defining a constricted opening having a reduced diameter less than an inner diameter of the lead body and a guide lumen extending from the proximal end to the distal end; an electrode operatively coupled to the conductor; a fixation mechanism configured to facilitate extension of a guiding member beyond the distal end of the lead body, the fixation mechanism comprising: a base disposed within the cavity, the base having an outer diameter greater than the reduced diameter of the constricted opening such that the circumferential lip is configured to engage and retain the base within the cavity; one or more expandable tines having a proximal end coupled to the base and extending in a distal direction away from the base, and a channel defined in and extending through the base, the channel facilitating extension of the guiding member beyond the distal end of the lead body, wherein the fixation mechanism is adapted to transition from an expanded position beyond the distal end of the lead body, to a retracted position located within the cavity, wherein when the fixation mechanism is in the expanded position, the base is engaged by the circumferential lip of the cavity such that the base is retained within the cavity at the distal end of the lead body and the one or more expandable tines extend in a distal direction away from the distal end of the lead body and the fixation mechanism remains associated within the distal end of the lead body; and a guiding member adapted to extend beyond the distal end of the lead body.