Patent ID: 7991484

Claim:
A method of determining whether a distal tip of an implantable medical lead is properly positioned relative to body tissue, the medical lead comprising an extendable/retractable helix electrode at the distal tip of the lead and an electrically conductive mapping collar disposed at said distal tip, the method comprising: (a) measuring an electrical impedance for the mapping collar to select an implant site along the body tissue; (b) extending the helix electrode so that it penetrates the body tissue at the selected implant site; (c) re-measuring the electrical impedance for the mapping collar after the helix has been extended; (d) comparing the measured electrical impedance for the mapping collar after the helix has been extended with a predetermined impedance value for the mapping collar; (e) if the measured electrical impedance value for the mapping collar is below said predetermined value, repositioning the helix electrode relative to the body tissue and repeating at least steps (c)-(e); and (f) if the measured electrical impedance value of the collar is equal to or above said predetermined value, retaining the distal tip of the lead at said selected implant site.