Patent ID: 7822484

Claim:
An implantable lead comprising: a lead body, defining a distal end and a proximal end, configured to be implanted in a patient; an electrode assembly provided at the distal end of the lead body, the electrode assembly comprising an electrode that is configured to deliver stimulating pulses, the electrode extending between a base and a tip at a distal end of the electrode and wherein the electrode assembly further includes an elongated shaft advanceable with respect to the distal end of the lead body, the electrode being coupled to the elongated shaft and being advanceable therewith; a conductor contained within the lead body and extending from the proximal end of the lead to the base of the electrode assembly; and a shielding member provided on the electrode assembly the shielding member having a shielding conductor positioned to cover at least a portion of the conductor and the electrode to electrically shield at least a portion of the conductor and a first portion of the electrode from RF fields and a fixation helix for securing the electrode assembly to cardiac tissue of the patient, the fixation helix configured to shield at least a second portion of the electrode from RF fields, wherein the fixation helix and the shielding conductor are electrically isolated from the electrode and wherein the shielding conductor is coupled to the elongated shaft and is advanceable therewith.