Selectively connecting the tip electrode during therapy for MRI shielding

A medical device lead comprising:

• a first conductor;
• an electrode distal of the first conductor and electrically coupled to the first conductor;
• a second conductor that is coaxial with the first conductor along at least a portion of the lead;
• an insulating layer radially between the first conductor and the second conductor along at least the portion of the lead, the insulating layer proximal of the electrode, the insulating layer having a breakdown voltage threshold between a first voltage associated with a current induced in the second conductor by an MRI system and a second voltage associated with therapeutic stimulation energy such that the insulating layer permits conduction of the therapeutic stimulation energy from the first conductor to the second conductor across the insulating layer and to the electrode but the insulating layer blocks the current induced by the MRI system from being transmitted from the first conductor to the second conductor to minimize current on the second conductor during an MRI scan;
• and
• an outer insulating layer extending around the first conductor and the second conductor and defining an exterior of the lead,
• wherein each of the insulating layer, the first conductor, the second conductor, and the outer insulating layer overlap each other along at least the portion of the lead.

A medical device comprising:

• a pulse generator configured to deliver therapeutic stimulation energy;
• and
• a lead comprising:
• a first conductor configured to electrically couple to the pulse generator;
• a second conductor coaxial with the first conductor along a portion of the lead;
• an electrode that is distal of the portion of the lead, the electrode electrically coupled with the second conductor;
• an insulating layer between the first conductor and the second conductor, the insulating layer proximal of the electrode and having a breakdown voltage threshold that is between a first voltage associated with a current induced by an MRI system on the first conductor and a second voltage associated with the therapeutic stimulation energy delivered by the pulse generator, the insulating layer configured to permit conduction of the therapeutic stimulation energy from the first conductor to the second conductor through the insulating layer but block conduction of the current induced by the MRI system from being transmitted from the first conductor to the second conductor through the insulating layer to minimize current on the second conductor during an MRI scan;
• and
• an outer insulating layer extending around the first conductor and the second conductor and defining an exterior of the lead,
• wherein each of the insulating layer, the first conductor, the second conductor, and the outer insulating layer overlap each other along at least the portion of the lead.