An electrode assembly for the positioning of an electrode of an implantable medical lead , the electrode assembly comprising: a housing including a proximal end for connecting to the lead and a distal end opposite the proximal end , the housing defining a housing lumen having a longitudinal axis , the housing lumen extending between the proximal end and the distal end , the housing lumen including internal screw threads extending along at least a portion of the housing lumen ; and characterized by further comprising an electrode subassembly disposed at least partially within the housing lumen , the electrode subassembly including: a needle electrode disposed coaxially with the longitudinal axis of the housing lumen ; a coupler disposed at a proximal end of the needle electrode , the coupler including external screw threads engaged with the internal screw threads of the housing lumen such that rotation of the coupler moves the needle electrode along the longitudinal axis of the housing lumen , wherein rotation of the coupler in a first direction moves the coupler and the needle electrode toward the distal end of the housing , and rotation of the coupler in a second direction opposite the first direction moves the coupler and the needle electrode toward the proximal end of the housing ; and by the electrode assembly further comprising an active fixation device connected to the housing and arranged so as to allow mapping of tissue via repositioning of the needle electrode by pushing on the lead to cause the needle electrode to penetrate the tissue and removing the needle electrode from the tissue by pulling on the lead to thereby provide mapping of the tissue prior to positioning the lead close enough to the tissue for implantation using the active fixation device . a housing including a proximal end for connecting to the lead and a distal end opposite the proximal end , the housing defining a housing lumen having a longitudinal axis , the housing lumen extending between the proximal end and the distal end , the housing lumen including internal screw threads extending along at least a portion of the housing lumen ; and characterized by further comprising an electrode subassembly disposed at least partially within the housing lumen , the electrode subassembly including: a needle electrode disposed coaxially with the longitudinal axis of the housing lumen ; a coupler disposed at a proximal end of the needle electrode , the coupler including external screw threads engaged with the internal screw threads of the housing lumen such that rotation of the coupler moves the needle electrode along the longitudinal axis of the housing lumen , wherein rotation of the coupler in a first direction moves the coupler and the needle electrode toward the distal end of the housing , and rotation of the coupler in a second direction opposite the first direction moves the coupler and the needle electrode toward the proximal end of the housing ; a needle electrode disposed coaxially with the longitudinal axis of the housing lumen ; a coupler disposed at a proximal end of the needle electrode , the coupler including external screw threads engaged with the internal screw threads of the housing lumen such that rotation of the coupler moves the needle electrode along the longitudinal axis of the housing lumen , wherein rotation of the coupler in a first direction moves the coupler and the needle electrode toward the distal end of the housing , and rotation of the coupler in a second direction opposite the first direction moves the coupler and the needle electrode toward the proximal end of the housing ; <EOS>