Patent ID: 8271097
Filing Date: 2012-09-18
Classification: A61N

Abstract:
1. An electrical lead, comprising: a flexible body having a length, a proximal region with a proximal end, and a distal region with a distal end; an extendable and retractable fixation helix assembly coupled to the distal end of the lead body, including a housing, a coupler disposed within the housing having a proximal portion and a distal portion, a fixation helix fixedly secured to the distal portion of the coupler, and a guide structure within the housing operable to cause the coupler and the fixation helix to translate longitudinally upon rotation of the coupler and fixation helix relative to the housing; a connector assembly coupled to the proximal end of the flexible body to electrically and mechanically connect the electrical lead to an implantable pulse generator, wherein the connector assembly includes: an electrically inactive torque tube disposed longitudinally within the flexible body and mechanically connected to the distal end of the terminal pin and to the proximal portion of the coupler such that rotation of the terminal pin relative to the flexible body causes rotation and longitudinal translation of the coupler and the fixation helix relative to the flexible body; a multi-filar conductor coil disposed longitudinally within the flexible body, the multi-filar conductor coil including at least a first filar defining a first conduction path and at least a second filar defining a second conductive path electrically isolated from the first conductive path, the first and second filars co-radially wound to form the multi-filar conductor coil, the first filar electrically coupled to the annular inner terminal ring and thereby electrically coupled to the terminal pin through the resilient C-clip, the second filar electrically coupled to the outer terminal ring, the conductor coil being substantially fixed relative to the flexible body, the first and second filars dimensioned to have an impedance of about several thousand ohms or higher when exposed to an external magnetic field characterized by 1.5 Tesla to 3.0 Tesla; a first electrode coupled to the flexible body in the distal region and electrically coupled to the first filar; and a second electrode coupled to the flexible body in the distal region and electrically coupled to the second filar.