Resonance tuning module for implantable devices and leads

• US 9,037,257 B2
• Filed: 04/05/2007
• Issued: 05/19/2015
• Est. Priority Date: 04/07/2006
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Gray, Robert W., MacDonald, Stuart G.
• Primary Examiner(s): Koharski, Christopher D
• Assistant Examiner(s): Bays, Pamela M
• Application Number:
  US11/696,857
• Publication Number:
  US 20080058902A1
• Time in Patent Office: 2,966 Days
• Field of Search: 324/322, 600/424, 607/2, 607/63, 607115-117, 348/61
• US Class Current: 607/63
• CPC Class Codes: A61N 1/025 Digital circuitry features of electrotherapy devices, e.g. memory, clocks, processors
• CPC Class Codes: A61N 1/05 for implantation or insertion into the body, e.g. heart electrode A61N1/06 takes precedence
• CPC Class Codes: A61N 1/086 Magnetic resonance imaging [MRI] compatible leads
• 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 1/37211 Means for communicating with stimulators
• CPC Class Codes: A61N 1/37223 Circuits for electromagnetic coupling
• CPC Class Codes: A61N 1/375 Constructional arrangements, e.g. casings
• CPC Class Codes: A61N 1/3758 Packaging of the components within the casing

Abstract

An implantable medical assist device includes a medical device. The medical device has a housing and electronics contained therein. A lead provides an electrical path to or from the electronics within the medical device. A resonance tuning module is located in the housing and is connected to the lead. The resonance tuning module includes a control circuit for determining a resonant frequency of the implantable medical assist device and an adjustable impedance circuit to change the combined resonant frequency of the medical device and lead.

Claims

1. An implantable medical assist system, comprising:

a medical device including a housing and electronics contained therein;

a lead having a length to provide an electrical path to or from the electronics within the medical device to tissue; and

a resonance tuning module located in the housing and operatively connected to the lead,

the resonance tuning module including,

a control and adjustment subsystem configured to determine a resonant frequency of the implantable medical assist system after implantation of the medical assist system, and

an adjustable impedance circuit comprising at least one of an adjustable inductive element or an adjustable capacitive element, wherein, based on the resonant frequency of the implantable medical assist system determined after implantation of the medical assist system, the control and adjustment subsystem adjusts at least one of the adjustable inductive element or the adjustable capacitive element to adjust an impedance of the adjustable impedance circuit to change the resonant frequency of the medical assist system after implantation.

2. The implantable medical assist system of claim 1, wherein the control and adjustment subsystem operatively controls the impedance of the adjustable impedance circuit to change the resonant frequency of the implantable medical assist system to be substantially equal to a desired resonant frequency.

3. The implantable medical assist system of claim 2, wherein the control and adjustment subsystem operatively controls an impedance of the adjustable impedance circuit to readjust the resonant frequency of the implantable medical assist system to be substantially equal to a second desired resonant frequency.

4. The implantable medical assist system of claim 3, wherein the first desired resonant frequency is approximately 64 MHz and the second desired resonant frequency is approximately 128 MHz.

5. The implantable medical assist system of claim 1, wherein the control and adjustment subsystem operatively controls the impedance of the adjustable impedance circuit to change the resonant frequency of the implantable medical assist system to be substantially equal to a radio-frequency of a magnetic resonance imaging scanner.

6. The implantable medical assist system of claim 1, wherein the control and adjustment subsystem operatively controls the impedance of the adjustable impedance circuit to change the resonant frequency of the implantable medical assist system and the lead to be substantially equal to 64 Mhz.

7. The implantable medical assist system of claim 1, wherein the control and adjustment subsystem operatively controls the impedance of the adjustable impedance circuit to change the resonant frequency of the implantable medical assist system and the lead to be substantially equal to 128 MHz.

8. The implantable medical assist system of claim 1, wherein the control and adjustment subsystem operatively controls the impedance of the adjustable impedance circuit to change the resonant frequency of the implantable medical assist system and the lead to be not perfectly tuned to a radio-frequency of a magnetic resonance imaging scanner.

9. The implantable medical assist system of claim 1, wherein the control and adjustment subsystem operatively controls the impedance of the adjustable impedance circuit to change the resonant frequency of the implantable medical assist system and the lead to be not perfectly tuned to 64 Mhz.

10. The implantable medical assist system of claim 1, wherein the control and adjustment subsystem operatively controls the impedance of the adjustable impedance circuit to change the resonant frequency of the implantable medical assist system to be not perfectly tuned to 128 MHz.

11. The implantable medical assist system of claim 1, wherein the adjustable impedance circuit includes a variable inductor and a variable capacitor.

12. The implantable medical assist system of claim 1, wherein the adjustable impedance circuit includes an adjustable inductive circuit and an adjustable capacitive circuit.

13. The implantable medical assist system of claim 1, wherein the adjustable impedance circuit includes a variable inductor, a variable capacitor, and a variable resistor.

14. The implantable medical assist system of claim 1, wherein the adjustable impedance circuit includes an adjustable inductive circuit, an adjustable capacitive circuit, and an adjustable resistive circuit.

15. The implantable medical assist system of claim 1, wherein the control and adjustment subsystem iteratively determines the resonant frequency of the implantable medical assist system and iteratively adjusts the impedance of the adjustable impedance circuit until the resonant frequency of the medical assist system reaches a desired resonant frequency.

16. The implantable medical assist system of claim 1, wherein the resonance tuning module receives instructions after implantation instructing the resonance tuning module to adjust the resonant frequency of the implantable medical assist system to a desired resonant frequency.

17. An implantable medical assist system, comprising:

a medical device including a housing and electronics contained therein;

a first lead to provide an electrical path to or from the electronics within the medical device;

a resonance tuning module; and

a second lead to provide an electrical path to or from the resonance tuning module;

the resonance tuning module including,

a control and adjustment subsystem configured to determine a resonant frequency of the implantable medical assist system after implantation of the medical assist system, and an adjustable impedance circuit comprising at least one of an adjustable inductive element or an adjustable capacitive element, wherein, based on the resonant frequency of the implantable medical assist system determined after implantation of the medical assist system, the control and adjustment subsystem adjusts at least one of the adjustable inductive element or the adjustable capacitive element to adjust an impedance of the adjustable impedance circuit to change the resonant frequency of the medical assist system after implantation.

18. An implantable medical assist system, comprising:

a medical device including a housing and therapy providing electronics contained therein;

a lead having a length to provide an electrical path to or from the electronics within the medical device to tissue to receive therapy; and

a resonance tuning module located in the housing and operatively connected to the lead;

the resonance tuning module including,

a control and adjustment subsystem configured to determine a resonant frequency of the implantable medical assist system after implantation of the medical assist system, and an adjustable impedance circuit comprising at least one of an adjustable inductive element or an adjustable capacitive element, wherein, based on the resonant frequency of the implantable medical assist system determined after implantation of the medical assist system, the control and adjustment subsystem adjusts at least one of the adjustable inductive element or the adjustable capacitive element to adjust an impedance of the adjustable impedance circuit to change the resonant frequency of the medical assist system to be substantially equal to a radio-frequency of a magnetic resonance imaging scanner after implantation.