Apparatus and method for shunting induced currents in an electrical lead

• US 20030083723A1
• Filed: 10/31/2001
• Published: 05/01/2003
• Est. Priority Date: 10/31/2001
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Reinke, James D., Zeijlemaker, Volkert A., Wilkinson, Jeffrey D.
• Granted Patent: US 6,871,091 B2
• Time in Patent Office: Days
• US Class Current: 607/122
• CPC Class Codes: A61N 1/056 Transvascular endocardial electrode systems
• CPC Class Codes: A61N 1/086 Magnetic resonance imaging [MRI] compatible leads

Abstract

An electrical lead includes an elongate body having a proximal end portion and a distal end portion, a first electrode disposed adjacent and joined to the distal end portion of the elongate body, and a first conductor extending between the proximal end portion and the distal end portion of the elongate body and being electrically coupled to the first electrode. The medical electrical lead further comprises a second electrode disposed adjacent the first electrode and joined to the elongate body and a capacitive device electrically coupled to the first conductor and the second electrode.

Claims

1. An electrical lead, comprising:

an elongate body having a proximal end portion and a distal end portion;

a first electrode disposed adjacent and joined to the distal end portion of the elongate body;

a first conductor extending between the proximal end portion and the distal end portion of the elongate body and being electrically coupled to the first electrode;

a second electrode disposed adjacent the first electrode and joined to the elongate body; and

a capacitive device electrically coupled to the first conductor and the second electrode.

2. An electrical lead, according to claim 1, further comprising a second conductor extending between the proximal end portion of the elongate body and the second electrode and being electrically coupled to the second electrode.

3. An electrical lead, according to claim 1, further comprising:

a third electrode disposed adjacent the second electrode and joined to the elongate body; and

a second conductor extending between the proximal end portion of the elongate body and the third electrode and being electrically coupled to the third electrode.

4. An electrical lead, according to claim 1, wherein:

the capacitive device further comprises a discoidal capacitor having a central contact and a peripheral contact;

the first conductor is electrically coupled with the central contact; and

the second electrode is electrically coupled with the peripheral contact.

5. An electrical lead, according to claim 1, wherein:

the first electrode and the second electrode are capable of being electrically coupled with body tissue;

the first conductor is capable of transmitting an electrical current; and

the capacitive device has an electrical impedance substantially less than electrical impedance of the body tissue at signal frequencies greater than those used to sense biological signals or deliver electrical stimulation to the body tissue.

6. An electrical lead, according to claim 1, wherein:

the first electrode and the second electrode are capable of being electrically coupled with body tissue;

the first conductor is capable of transmitting an electrical current; and

the capacitive device has an electrical impedance substantially greater than an electrical impedance of the body tissue at signal frequencies used to sense biological signals or deliver electrical stimulation to the body tissue.

7. An electrical lead, according to claim 1, wherein an area of the second electrode is at least three times an area of the first electrode.

8. An electrical lead, according to claim 1, wherein the capacitive device is capable of allowing at least a portion of a current, induced in the first conductor by a field, to be routed to the second electrode.

9. A shunting assembly, comprising:

an electrode;

a conductor; and

a capacitive device electrically coupled with the electrode and the conductor.

10. A shunting assembly, according to claim 9, wherein:

the capacitive device further comprises a discoidal capacitor having a central contact and a peripheral contact;

the conductor is electrically coupled with the central contact; and

the electrode is electrically coupled with the peripheral contact.

11. A shunting assembly, according to claim 9, wherein:

the capacitive device further comprises a first discoidal capacitor having a central contact and a peripheral contact and a second discoidal capacitor having a central contact and a peripheral contact;

the conductor further comprises a first pin and a second pin electrically coupled by a central conductor;

the first pin is electrically coupled with the central contact of the first discoidal capacitor;

the second pin is electrically coupled with the central contact of the second discoidal capacitor; and

the electrode is electrically coupled with the peripheral contact of the first discoidal capacitor and the peripheral contact of the second discoidal capacitor.

12. A shunting assembly, according to claim 9, wherein:

the electrode is capable of being electrically coupled with body tissue;

the conductor is capable of transmitting an electrical current; and

the capacitive device has an electrical impedance of less than an electrical impedance of the body tissue when the electrical current is induced during MRI or diathermy therapies.

13. A shunting assembly, according to claim 9, wherein:

the electrode is capable of being electrically coupled with body tissue;

the conductor is capable of transmitting an electrical current; and

the capacitive device has an electrical impedance of greater than an electrical impedance of the body tissue when transferring a signal having at frequencies of the electrical current less than or equal to 500 hertz.

14. A shunting assembly, according to claim 9, wherein the electrode further comprises a tube having a first end and a second end, wherein the shunting assembly further comprises:

a first end cap joined to the first end of the tube; and

a second end cap joined to the second end of the tube.

15. A shunting assembly, according to claim 9, wherein the shunting assembly is hermetically sealed.

16. A shunting assembly, according to claim 15, wherein the capacitive device is capable of allowing at least a portion of a current, induced in the first conductor by a field, to be routed to the second electrode.

17. A medical device, comprising:

a control unit;

an elongate body having a proximal end portion coupled with the control unit and a distal end portion;

a first electrode disposed adjacent and joined to the distal end portion of the elongate body;

a first conductor extending between the proximal end portion and the distal end portion of the elongate body and being electrically coupled to the first electrode and the control unit;

a second electrode disposed adjacent the first electrode and joined to the elongate body; and

a capacitive device electrically coupled to the first conductor and the second electrode.

18. A medical device, according to claim 17, further comprising a second conductor extending between the proximal end portion of the elongate body and the second electrode and being electrically coupled to the second electrode and the control unit.

19. A medical device, according to claim 17, further comprising:

a third electrode disposed adjacent the second electrode and joined to the elongate body; and

a second conductor extending between the proximal end portion of the elongate body and the third electrode and being electrically coupled to the third electrode and the control unit.

20. A medical device, according to claim 17, wherein:

the capacitive device further comprises a discoidal capacitor having a central contact and a peripheral contact;

the first conductor is electrically coupled with the central contact; and

the second electrode is electrically coupled with the peripheral contact.

21. A medical device, according to claim 17, wherein:

the first electrode and the second electrode are capable of being electrically coupled with body tissue;

the first conductor is capable of transmitting an electrical current; and

the capacitive device has an electrical impedance of no more than about 20 percent of an electrical impedance of the body tissue at a frequency of the electrical current greater than about 1 Mhz.

22. A medical device, according to claim 17, wherein:

the first electrode and the second electrode are capable of being electrically coupled with body tissue;

the first conductor is capable of transmitting an electrical current; and

the capacitive device has an electrical impedance about ten times of an electrical impedance of the body tissue at a frequency of the electrical current less than 500 hertz..

23. A medical device, according to claim 17, wherein an area of the second electrode is at least three times an area of the first electrode.

24. A medical device, according to claim 17, wherein the capacitive device is capable of allowing at least a portion of a current, induced in the first conductor by a field, to be routed to the second electrode.

25. A medical device, according to claim 17, wherein the capacitive device is capable of preventing at least most of a signal transmitted over the first conductor from the control unit from being routed to the second electrode.

26. A medical device, according to claim 17, wherein the capacitive device is capable of preventing at least most of a signal transmitted over the first conductor to the control unit from being routed to the second electrode.

27. A method, comprising selectively routing an electrical current traveling through a conductor electrically coupled with body tissue over at least one of a primary path and a secondary path to the body tissue based upon a characteristic of the electrical current.

28. A method, according to claim 27, wherein selectively routing the electrical current traveling through the conductor further comprises selectively routing the electrical current traveling through the conductor over at least one of the primary path and the secondary path to the body tissue based upon the frequency of the electrical current.

29. A method, according to claim 27, wherein selectively routing the electrical current traveling through the conductor further comprises:

routing the current over the primary path and the secondary path to the body tissue if the current is induced in the conductor by a field; and

routing the current only over the primary path to the body tissue if the current is not induced in the conductor by the field.

30. An apparatus, comprising means for selectively routing an electrical current traveling through a conductor electrically coupled with body tissue over at least one of a primary path and a secondary path to the body tissue based upon a characteristic of the electrical current.

31. An apparatus, according to claim 30, wherein the means for selectively routing the electrical current traveling through the conductor further comprises means for selectively routing the electrical current traveling through the conductor over at least one of the primary path and the secondary path to the body tissue based upon the frequency of the electrical current.

32. An apparatus, according to claim 30, wherein the means for selectively routing the electrical current traveling through the conductor further comprises:

means for routing the current over the primary path and the secondary path to the body tissue if the current is induced in the conductor by a field; and

means for routing the current only over the primary path to the body tissue if the current is not induced in the conductor by the field.