His bundle mapping, pacing, and injection lead

An implantable endocardial pacing lead assembly for locating and delivering a pacing stimulus to a His bundle of a patient, the lead assembly comprising:

• a steerable stylet having a stylet distal end and a stylet proximal end, the steerable stylet including:
• a mapping electrode at the stylet distal end;
• a connector at the stylet proximal end;
• and
• a conductor electrically coupled between the mapping electrode and the connector;
• an implantable lead configured to be implanted in a patient and including:
• an elongate lead body having a lead proximal end and a lead distal end;
• a connector assembly at the proximal end of the lead body configured for coupling the lead to an implantable device configured to deliver therapy to the patient, the connector assembly including a rotatable terminal pin;
• a conductor coil extending within the lead body and mechanically and electrically coupled to the terminal pin;
• an extendable and retractable helical electrode at or near the lead distal end for sensing cardiac electrical activities and delivering pacing pulses, wherein the extendable and retractable electrode is rotatable and operable as a fixation helix and is coupled to the conductor coil;
• and
• a lumen within and extending through the lead body, the lumen including a proximal opening at about the lead proximal end and a distal opening at about the lead distal end, the lumen adapted to accommodate at least a portion of the steerable stylet and to allow the stylet distal end to enter the proximal opening and extend from the distal opening.