Patent ID: 7643886

Claim:
A medical electrical lead comprising: a lead body including a proximal portion and a distal portion and a primary lumen extending there between, the primary lumen adapted to receive a guiding member; at least one electrical conductor extending within the lead body; at least one electrode located on the lead body and operatively coupled to the at least one conductor; at least one hydraulic lumen having an inner wall formed in an outer sheath of the lead body, the at least one hydraulic lumen adapted to receive and contain a fluid; at least one plunger slideably disposed within the at least one hydraulic lumen adapted to receive and contain a fluid, wherein the plunger is moveable in a distal direction from a first position to a second position when hydraulic pressure is introduced into the lumen, the plunger comprising a plunger head in sealing contact with the inner wall of the at least one hydraulic lumen forming a circumferential seal facilitating hydraulic pressure build-up in the at least one hydraulic lumen; and at least one fixation portion along the lead body including at least one preformed fixation member having an expanded configuration and a collapsed configuration, the fixation member including a proximal end attached to an outer surface of the at least one fixation portion and a distal end attached to the plunger, wherein when the plunger is in the first position, the fixation member is in the expanded configuration.