Low profile active fixation cardiac lead having torque transmitting means

A cardiac lead comprising:

• a) an elongated lead body having opposed proximal and distal end portions and having an interior lumen extending therethrough;
• b) a rotatable fixation element operatively associated with the distal end portion of the lead body;
• c) a conductor coil extending through the interior lumen of the lead body wherein the conductor coil is a multifilar coil having interposed electrically active and inactive filars;
• d) a tubular torque transmitting member extending through the interior lumen of the lead body, coaxially arranged within the conductor coil, and having opposed proximal and distal ends, the proximal end of the tubular torque transmitting member connected to a rotatable actuator operatively and integrally connected with the proximal end portion of the lead body, such that rotation of the rotatable actuator causes corresponding rotation of the tubular torque transmitting member with respect to the elongated lead body and the conductor coil wherein the tubular torque transmitting member includes an electrically inactive helically wound coil;
• and
• e) a threaded plug associated with the distal end portion of the lead body, carrying the rotatable fixation element and operatively connected to the distal end of the tubular torque transmitting member, such that rotation of the tubular torque transmitting member by the rotatable actuator causes corresponding rotation of the fixation element.