Selectively connecting the tip electrode during therapy for MRI shielding

摘要

A medical device includes a pulse generator and an electrode configured to contact tissue in a body vessel. The medical device includes a lead that includes a lead connector. The lead connector connects a pulse generator with an electrode via a conductive path. An electrode switch is electrically connected between the lead conductor and the electrode. The electrode switch includes an open state preventing the conductive path between the lead and the electrode. The electrode switch includes a closed state establishing the conductive path between the lead and the electrode when a voltage is applied across the electrode switch that exceeds a threshold voltage. The electrode switch in the open state electrically shields the electrode from electromagnetic radiation and induced voltages during magnetic resonance imaging.

主权项

1. A medical device comprising:
a pulse generator configured to deliver one or more therapy pulses; an electrode configured to contact tissue in a body vessel; a lead comprising proximal and distal ends, the lead selectively connecting the pulse generator with the electrode via a conductive path; an inner conductor and an outer conductor, each of the inner conductor and the outer conductor extending within the lead and the outer conductor extending coaxially around the inner conductor, the inner conductor in electrical communication with the pulse generator, the outer conductor in electrical communication with the electrode; at least one portion of the lead located proximal of the electrode and between the proximal and distal ends, the at least one portion including an insulating material between the outer conductor and the inner conductor, the insulating material configured to:
exhibit a non-conductive state in which the insulating material is configured to block current induced in the outer conductor by an MRI system from being transmitted to the inner conductor to minimize current on the inner conductor during an MRI scan, andexhibit a conductive state in which the insulating material is configured to permit the one or more therapy pulses from the pulse generator to be transmitted between the inner conductor and the outer conductor through the insulating material, wherein the insulating material has a breakdown voltage threshold between a first voltage associated with the current induced by the MRI system and a second voltage associated with the stimulation energy; an outer insulating layer extending over and encapsulating the outer conductor; and wherein each of the insulating material, the outer conductor, and the outer insulating layer are concentrically disposed around the inner conductor at a cross section of the at least one portion of the lead that is orthogonal to a longitudinal axis of the lead.