Abstract: An implantable medical lead of the invention comprises an electrically active helix electrode extendable and retractable relative to a distal tip of the lead, an electrically conductive mapping collar disposed at the lead's distal tip and a proximal end carrying an electrical connector assembly. The electrical connector assembly comprises a first terminal connected to the helix electrode and a second terminal separately connected to the mapping collar. An advantage of the independent helix electrode and mapping collar circuits is that the implanting physician can confirm from separate electrode impedance readings that the helix is in fact extended and fully embedded within the myocardium. Further, the independent mapping collar and helix electrode circuits may be used, in conjunction with a configurable or programmable switch network, to provide the implanting physician with a choice of electrode impedances.

Abstract: An implant tool for use with an endocardial or other implantable lead having an extendable/retractable active fixation tip includes a housing, a shaft rotatably supported by the housing, and a shaft rotation mechanism for rotating the shaft through a predetermined angular travel. The shaft includes a lead attachment portion for selectively coupling a lead to the shaft such that the lead is rotatable with the shaft. The implant tool may include a control tab slidably supported by the housing, wherein longitudinal movement of the control tab actuates the shaft rotation mechanism. The shaft rotation mechanism may include a gear train, an electric motor, a double acting spring mechanism, or a retractable tape wound around the shaft. The gear train includes an input member coupled to the control tab and an output gear coupled to the shaft. The input member meshes with an input gear supported by the housing.

Abstract: An implantable medical lead of the invention comprises an electrically active helix electrode extendable and retractable relative to a distal tip of the lead, an electrically conductive mapping collar disposed at the lead's distal tip and a proximal end carrying an electrical connector assembly. The electrical connector assembly comprises a first terminal connected to the helix electrode and a second terminal separately connected to the mapping collar. An advantage of the independent helix electrode and mapping collar circuits is that the implanting physician can confirm from separate electrode impedance readings that the helix is in fact extended and fully embedded within the myocardium. Further, the independent mapping collar and helix electrode circuits may be used, in conjunction with a configurable or programmable switch network, to provide the implanting physician with a choice of electrode impedances.

Abstract: An implant tool for use with an endocardial or other implantable lead having an extendable/retractable active fixation tip includes a housing, a shaft rotatably supported by the housing, and a shaft rotation mechanism for rotating the shaft through a predetermined angular travel. The shaft includes a lead attachment portion for selectively coupling a lead to the shaft such that the lead is rotatable with the shaft. The implant tool may include a control tab slidably supported by the housing, wherein longitudinal movement of the control tab actuates the shaft rotation mechanism. The shaft rotation mechanism may include a gear train, an electric motor, a double acting spring mechanism, or a retractable tape wound around the shaft. The gear train includes an input member coupled to the control tab and an output gear coupled to the shaft. The input member meshes with an input gear supported by the housing.