Patent ID: 8532789

Claim:
A medical device system including an electrode configured to be subcutaneously placed at a target site in a patient using a lead that is adapted to extend within a subcutaneous tunnel wall of a patient's body tissue formed outside a patient's vascular system, comprising: the lead having a lead body extending from a proximal end to a distal end, the electrode configured to be positioned along the distal end of the lead; and a fixation mechanism configured to be positioned along the lead body proximal to the electrode, the fixation mechanism including a locking sleeve and a mating portion, the mating portion configured to be part of the lead body, the locking sleeve capable of being advanced distally along the lead body and over the mating portion, the locking sleeve having an inner surface facing the lead body and a flange extending from the inner surface of the locking sleeve toward the lead body, and the mating portion having a proximal section, a distal section and an intermediate section between the proximal section and the distal section, the intermediate section configured to form a channel for receiving the flange, wherein the proximal portion is sloped such that a diameter of the proximal section of the mating portion increases along a sloped surface from a proximal end of the proximal section to a distal end of the proximal section, wherein a diameter of the locking sleeve is increased as the locking sleeve is advanced over the proximal section of the mating portion, and wherein the flange has an inner diameter smaller than the inner diameter defined by the inner surface of the locking sleeve when the flange is located in the channel