FREQUENCY SELECTIVE PASSIVE COMPONENT NETWORKS FOR ACTIVE IMPLANTABLE MEDICAL DEVICES UTILIZING AN ENERGY DISSIPATING SURFACE

• US 20100217262A1
• Filed: 03/31/2010
• Published: 08/26/2010
• Est. Priority Date: 04/13/2001
• Status: Active Grant

• Current Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Original Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Inventors: Frysz, Christine A., Dabney, Warren S., Stevenson, Robert A., Lardo, Albert C., Truex, Buehl E., Halperin, Henry R.
• Granted Patent: US 8,219,208 B2
• Time in Patent Office: Days
• US Class Current: 606/41
• CPC Class Codes: A61B 18/1492 having a flexible, catheter-like structure, e.g. for heart ablation A61B18/1477 takes precedence
• CPC Class Codes: A61B 2018/00839 Bioelectrical parameters, e.g. ECG, EEG
• CPC Class Codes: A61B 2090/374 NMR or MRI
• CPC Class Codes: A61B 2562/182 Electrical shielding, e.g. using a Faraday cage
• CPC Class Codes: A61B 2562/222 Electrical cables or leads therefor, e.g. coaxial cables or ribbon cables
• CPC Class Codes: A61B 2562/227 Sensors with electrical connectors
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61B 5/283 Invasive
• 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
• CPC Class Codes: G01R 33/287 involving active visualization of interventional instruments, e.g. using active tracking RF coils or coils for intentionally creating magnetic field inhomogeneities

Abstract

Decoupling circuits are provided which transfer energy induced from an MRI pulsed RF field to the housing for an active implantable medical device (AIMD) which serves as an energy dissipating surface. This is accomplished through broadband filtering or by resonant filtering. In a passive component network for an AIMD, a frequency selective energy diversion circuit is provided for diverting high-frequency energy away from an AIMD lead to the AIMD housing for dissipation of said high-frequency energy.

Claims

1. A passive component network for an active implantable medical device, comprising:

an active implantable medical device (AIMD) having a conductive housing;

at least one lead having a length extending between and to a proximal end adjacent to the AIMD housing and a tissue-stimulating or biological-sensing electrode at a distal tip end; and

a frequency selective energy diversion circuit for diverting high-frequency energy away from the lead to the AIMD housing for dissipation of said high-frequency energy.

2. The passive component network of claim 1, wherein the high frequency energy comprises an MRI frequency.

3. The passive component network of claim 2, wherein said MRI frequency comprises a range of MRI frequencies.

4. The passive component network of claim 2, wherein said MRI frequency in megahertz is selected from the group of frequencies comprising 42.56 times the static magnetic field strength in Teslas of an MRI scanner.

5. The passive component network of claim 1 or 2, wherein the frequency selective energy diversion circuit comprises a low pass filter.

6. The passive component network of claim 5, wherein the low pass filter comprises a capacitor, an inductor, a Pi filter, a T filter, an LL filter, or an “

n”

element filter.

7. The passive component network of claim 1 or 2, wherein the frequency selective energy diversion circuit comprises at least one series resonant LC trap filter.

8. The passive component network of claim 7, wherein the frequency selective energy diversion circuit comprises a plurality of LC trap filters resonant respectively at different MRI frequencies.

9. The passive component network of claim 1, including an impeding circuit associated with the diversion circuit, for raising the high-frequency impedance of a lead or a leadwire, said impeding circuit being disposed between said diversion circuit and AIMD electronic circuits.

10. The passive component network of claim 9 wherein said impeding circuit comprises at least one inductor.

11. The passive component network of claim 10 wherein said at least one inductor comprises an inductor chip.

12. The passive component network of claim 10 wherein said at least one inductor comprises an inductor wire wound onto a ferromagnetic or non-ferromagnetic mandrel.

13. The passive component network of claim 10, wherein said at least one inductor comprises a pair of inductor elements, said diversion circuit being coupled between said pair of inductor elements and said AIMD housing.

14. The passive component network of claim 13 wherein said diversion circuit comprises at least one capacitor.

15. The passive component network of claim 9, wherein the impeding circuit comprises a bandstop filter.

16. The passive component network of claim 1, wherein said at least one lead comprises at least a pair of leads each having a length extending between and to a proximal end adjacent to the AIMD housing and a tissue-stimulating or biological-sensing electrode at a distal tip end.

17. The passive component network of claim 16, wherein said diversion circuit couples each of said leads to the AIMD housing.

18. The passive component network of claim 16 or 17, wherein said diversion circuit is coupled between said pair of leads.

19. The passive component network of claim 1, wherein said diversion circuit is disposed within said AIMD housing.

20. The passive component network of claims 9 of 19, wherein said conductive housing protects said diversion and impeding circuits from direct contact with patient body fluids.

21. The passive component network of claim 19, wherein said active implantable medical device (AIMD) comprises a deep brain stimulator.

22. The passive component network of claim 1 or 2, wherein the active implantable medical device (AIMD) comprises a probe or a catheter.

23. The passive component network of claim 22, wherein said electrode comprises an ablation tip electrode.

24. The passive component network of claim 22, wherein the AIMD housing comprises at least a portion of a handle for the probe or the catheter.

25. The passive component network of claim 6, wherein the capacitor comprises parasitic capacitance.