SELECTIVELY CONNECTING THE TIP ELECTRODE DURING THERAPY FOR MRI SHIELDING

• US 20120071941A1
• Filed: 11/22/2011
• Published: 03/22/2012
• Est. Priority Date: 12/06/2007
• Status: Active Grant

• Current Assignee: Masoud Ameri
• Original Assignee: Masoud Ameri
• Inventors: Ameri, Masoud
• Granted Patent: US 8,897,875 B2
• Time in Patent Office: Days
• US Class Current: 607/9
• CPC Class Codes: A61N 1/056 Transvascular endocardial electrode systems
• CPC Class Codes: A61N 1/086 Magnetic resonance imaging [MRI] compatible leads
• CPC Class Codes: A61N 1/3718 Monitoring of or protection against external electromagnetic fields or currents

Abstract

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.

Claims

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 connecting the pulse generator with the electrode via a conductive path;

at least one portion of the lead between the proximal and distal ends including an insulating material between an outer conductor and an inner conductor, the insulating material including a non-conductive state preventing the conductive path between the lead pulse generator and the electrode, the insulating material including a conductive state allowing formation of the conductive path between the lead and the electrode when receiving a voltage applied across the insulating material exceeding a voltage threshold of the insulating material; and

wherein the insulating material in the non-conductive state electrically shields the electrode from at least electromagnetic radiation and induced voltages during magnetic resonance imaging.

2. The medical device of claim 1, wherein

the pulse generator is in electrical communication with the outer conductor, and

the electrode is in electrical communication with the inner conductor.

3. The medical device of claim 1, wherein

the pulse generator is in electrical communication with the inner conductor, and

the electrode is in electrical communication with the outer conductor.

4. The medical device of claim 1, wherein the at least one portion of the lead extends along the length of the lead between the proximal and distal ends.

5. The medical device of claim 1, wherein the at least one portion of the lead is formed at the distal end.

6. The medical device of claim 1, wherein the voltage applied across the insulating material is from at least one therapy pulse from the one or more therapy pulses from the pulse generator.

7. The medical device of claim 6, wherein the voltage applied across the insulating material from the at least one therapy pulse exceeds the threshold voltage.

8. A medical device lead comprising:

a first conductor;

a second conductor coaxial with the first conductor; and

an insulating layer between the first conductor and second conductor, the insulating layer having a breakdown voltage such that a conductive path is generated between the first conductor and second conductor across the insulating layer when a voltage on one of the first and second conductors exceeds the breakdown voltage.

9. The medical device lead of claim 8, and further comprising:

an electrode electrically coupled to the first conductor.

10. The medical device lead of claim 9, wherein the second insulator is configured to deliver an electrical signal exceeding the breakdown voltage that is conducted to the first conductor across the insulating layer.

11. The medical device lead of claim 8, wherein the insulating layer comprises a variable resistor.

12. The medical device lead of claim 8, wherein the breakdown voltage is greater than a voltage induced on the first conductor or second conductor during magnetic resonance imaging.

13. The medical device lead of claim 8, wherein the insulating layer extends only along a portion of the lead.

14. The medical device lead of claim 13, wherein the insulating layer extends along a distal portion of the lead.

15. A medical device comprising:

a pulse generator;

a lead comprising;

a first conductor configured to electrically couple to the pulse generator;

a second conductor coaxial with the first conductor; and

an insulating layer between the first conductor and second conductor, the insulating layer having a breakdown voltage,

wherein the pulse generator is configured to provide an electrical signal exceeding the breakdown voltage on the first conductor that is conducted from the first conductor to the second conductor across the insulating layer.

16. The medical device of claim 15, and further comprising:

an electrode electrically coupled to the second conductor.

17. The medical device of claim 15, wherein the insulating layer comprises a variable resistor.

18. The medical device of claim 15, wherein the breakdown voltage is greater than a voltage induced on the first conductor during magnetic resonance imaging.

19. The medical device of claim 15, wherein the insulating layer extends only along a portion of the lead.

20. The medical device of claim 19, wherein the insulating layer extends along a distal portion of the lead.