MRI-resistant implantable device

• US 20020038135A1
• Filed: 04/20/2001
• Published: 03/28/2002
• Est. Priority Date: 04/20/2000
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Biophan Technologies Incorporated
• Inventors: Weiner, Michael, Connelly, Patrick R., Greatbatch, Wilson
• Granted Patent: US 6,795,730 B2
• Time in Patent Office: Days
• US Class Current: 607/32
• CPC Class Codes: A61N 1/37 Monitoring; Protecting
• CPC Class Codes: A61N 1/3718 Monitoring of or protection against external electromagnetic fields or currents
• CPC Class Codes: A61N 1/375 Constructional arrangements, e.g. casings
• CPC Class Codes: A61N 1/37512 Pacemakers

Abstract

An implantable device used to monitor and maintain at least one physiologic function, which is capable of operating in the presence of damaging electromagnetic interference. The implantable device includes primary and secondary modules, each independently protected from EMI damage via at least one shielding and/or filtering, and a non-electrical communication device for communicating in at least one direction between the primary and the secondary modules. The primary module, in response to input from electrical sensing leads, activates the secondary module in a failsafe mode. In the failsafe mode, the secondary module carries out a physiologic function upon activation and in the presence of electromagnetic interference.

Claims

1. An implantable device used to monitor and maintain at least one physiologic function, the device being capable of operating in the presence of an electromagnetic interference, comprising:

a primary module;

a secondary module, each one of the primary module and the secondary module being independently protected from damage due to the electromagnetic interference via at least one of a shielding and a filtering; and

a non-electrical communication device for communicating in at least one direction between the primary module and the secondary module,

wherein the primary module, in response to an input from electrical sensing leads, activates the secondary module and a failsafe mode, and

wherein the secondary module carries out the at least one physiologic function upon activation and in the presence of the electromagnetic interference.

2. An implantable device as in claim 1, wherein the implantable device returns to a normal operating mode upon a cessation of the electromagnetic interference.

3. An implantable device as in claim 1, wherein the shielding includes one of a non-magnetic metal, carbon, a carbon composite, and a combination thereof.

4. An implantable device as in claim 1, wherein the non-electrical communication device includes one of a transparent window and a port, and wherein a communication provided by the non-electrical communication device, including the activation of the secondary module, is via an optical signal.

5. An implantable device as in claim 1, wherein the failsafe mode is effectuated by opening at least one electrical circuit, so as to prevent an externally-applied electrical current from damaging the at least one electrical circuit.

6. An implantable device as in claim 1, wherein the at least one physiologic function is a cardiac assist function, and wherein the implantable device is a cardiac assist device.

7. An implantable device as in claim 6, wherein the implantable device is at least one of a pacemaker and a defibrillator.

8. An implantable device as in claim 6, wherein the shielding is one of a non-magnetic metal, a carbon, a carbon composite, and a combination thereof.

9. An implantable device as in claim 6, wherein the non-electrical communication device for at least uni-directional communication is one of a transparent window and a port, and wherein a communication provided by the non-electrical commination device, including the activation of the secondary module, is via an optical signal.

10. An implantable device as in claim 6, wherein the failsafe mode is effectuated by opening at least one electrical circuit, so as to prevent an externally-applied electrical current from damaging the at least one electrical circuit.

11. An implantable device resistant to an electromagnetic interference, comprising:

a primary module, the primary module controlling an operation during a first mode, and including a processor switching off control of the implantable device during a second mode; and

a secondary module, hermetically sealed from the primary module, the secondary module including circuitry resistant to the electromagnetic interference, the circuitry controlling the operation during the second mode, the circuitry being inoperative during the first mode,

wherein in response to a presence of at least one of a magnitude of the electromagnetic interference exceeding a threshold level and an internal malfunction, the processor of the primary module switches the primary module to the second mode, and causes the secondary module to be switched into the second mode.

12. An implantable device as in claim 11, further comprising:

an optical communication device positioned between the primary module and the secondary module, the optical communication device hermetically sealed from the primary module and the secondary module by sealing fixtures.

13. An implantable device as in claim 12, wherein:

the primary module includes an optical source unit coupled to the processor, the optical source unit transmitting radiation through the optical communication device only during the first mode; and

the secondary module includes an optical detector, the optical detector receiving the radiation transmitted by the optical source unit of the primary module via the optical communication device, the optical detector transmitting a signal to activate the secondary module during the second mode when an absence of the radiation from the optical source unit of the primary module is detected.

14. An implantable device as in claim 12, wherein the optical communication device is a lens.

15. An implantable device as in claim 13, wherein the primary module and the secondary module are each enclosed within a separate non-magnetic shielding resistant to the electromagnetic interference.

16. An implantable device as in claim 15, wherein the primary module and the secondary module are enclosed with a flexible, non-magnetic, bio-compatible layer resistant to the electromagnetic interference.

18. An implantable device as in claim 17, wherein:

the non-electrical arrangement for allowing the communication includes an optical window.

19. An implantable device as in claim 17, wherein:

the first module is active during the first mode and inactive during the second mode, and

the second module is inactive during the first mode and active during the second mode.

20. An implantable device as in claim 19, wherein:

during the first mode, the first module performs a cardiac pacing function, and

during the second mode, the second module performs the cardiac pacing function.

17. An implantable device, comprising:

a first module for performing an operation in a first mode;

a second module for performing the operation in a second mode; and

a non-electrical arrangement for allowing a communication to occur between the first module and the second module.