Patent ID: 8052731

Claim:
A medical electrical lead configured to be partially implanted in a cardiac vessel, the lead comprising: an elongate body defining a proximal region and a distal region, the distal region including: an electrode on the body; and a fixation feature including a radially expandable structure having a first end fixedly attached to the body and a second end slidably coupled to the body, the radially expandable structure adapted to change from a radially collapsed configuration to a radially expanded configuration, the fixation feature further including a floating ring disposed about and slidable along the body and fixedly attached to the second end of the radially expandable structure, and a membrane made of a tissue ingrowth resistant material configured to substantially prevent tissue ingrowth; a conductor disposed within the body and electrically coupled to the electrode; and a tendon housed at least partially within the body and operatively connected to the second end of the radially expandable structure to facilitate selection between the radially collapsed and radially expanded configurations of the radially expandable structure.