Single sensor for physiologic signal measurement with position and tissue proximity indication

A catheter comprising:

• a tubular shaft extending along a longitudinal axis;
• and
• a coaxial wire wound around the tubular shaft forming a sensor, the coaxial wire comprising:
• a core conductive member;
• an inner insulation over the core conductive member and electrically insulating the core conductive member from an external environment to the coaxial wire;
• an outer conductive member extending over the inner insulation and electrically insulated from the core conductive member by the inner insulation;
• and
• an outer insulation over a portion of the outer conductive member such that uninsulated portions of the outer conductive member are exposed to the external environment to the sensor at two or more windings of the coaxial wire.

A guide wire comprising:

• a tubular shaft extending along a longitudinal axis;
• and
• a coaxial wire extending from a distal end of the tubular shaft and wound about the longitudinal axis forming a sensor, the coaxial wire comprising:
• a core conductive member;
• an inner insulation over the core conductive member and electrically insulating the core conductive member from an external environment to the coaxial wire;
• an outer conductive member extending over the inner insulation and electrically insulated from the core conductive member by the inner insulation;
• and
• an outer insulation over a portion of the outer conductive member such that uninsulated portions of the outer conductive member are exposed to the external environment to the sensor at two or more windings of the coaxial wire forming the sensor.