MRI-compatible pacemaker with power carrying photonic catheter and isolated pulse generating electronics providing VOO functionality

• US 20020116029A1
• Filed: 05/24/2001
• Published: 08/22/2002
• Est. Priority Date: 02/20/2001
• Status: Abandoned Application

• Current Assignee: Biophan Technologies Incorporated
• Original Assignee: Biophan Technologies Incorporated
• Inventors: Weiner, Michael, Greatbatch, Wilson, Miller, Victor, Connelly, Patrick
• Application Number:
  US09/865,049
• Publication Number:
  US 20020116029A1
• 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
• CPC Class Codes: A61N 1/37512 Pacemakers
• CPC Class Codes: G01R 33/285 Invasive instruments, e.g. catheters or biopsy needles, specially adapted for tracking, guiding or visualization by NMR
• CPC Class Codes: G01R 33/288 Provisions within MR facilities for enhancing safety during MR, e.g. reduction of the specific absorption rate [SAR], detection of ferromagnetic objects in the scanner room

Abstract

An MRI-compatible, fixed-rate (VOO) pacemaker includes a self-contained power source housed at the proximal end of a photonic catheter in a first enclosure. Low energy continuous electrical power is delivered from the power source. This electrical power is converted into light energy and directed into the proximal end of the photonic catheter. The photonic catheter includes an optical conduction pathway over which is formed a covering of biocompatible material. Light entering the proximal end of the photonic catheter is transmitted through the optical conduction pathway, where it is collected and converted back to electrical energy at a second enclosure located at the distal end of the photonic catheter. The second enclosure houses a pulse generator that stores electrical energy and periodically releases that energy to deliver electrical pulses to bipolar heart electrodes. One of the electrodes comprises the second enclosure housing the pulse generator and the other electrode is provided by another enclosure that is spaced from the second enclosure. The electrical pulses are delivered to the electrodes at an amplitude of about 3.3 volt and a current of about 3 milliamperes for a total pulse power output of about 10 milliwatts. A 1 millisecond pulse duration and a 1000 millisecond period may be provided for steady state VOO operation. The foregoing arrangement permits the use of photo elements operating in the microwatt region rather than at the milliwatt level as would be required if the output of the electronic pulse generator were delivered directly to the heart itself from the first enclosure in conventional pacemaker fashion.

Claims

1. An MRI-compatible implantable cardiac pacemaker, comprising:

a photonic catheter;

a self-contained electrical power source housed at a proximal end of said photonic catheter;

electrically powered pulsing circuitry housed at a distal end of said photonic catheter;

first power conversion means for converting the output of said electrical power source to optical energy for transmission through said photonic catheter; and

second power conversion means for converting said optical energy transmitted through said photonic catheter to electrical energy for powering said pulsing circuitry.

2. A pacemaker in accordance with claim 1, wherein said electrical power source and said pulsing circuitry are respectively housed in first and second enclosures that are hermetically sealed and made from non-magnetic metallic material.

3. A pacemaker in accordance with claim 2, wherein said material is titanium.

4. A pacemaker in accordance with claim 2, wherein said material is platinum or an alloy containing platinum.

5. A pacemaker in accordance with claim 1, wherein said photonic catheter includes a fiber optic conduction pathway.

6. A pacemaker in accordance with claim 1, wherein said fiber optic conduction pathway is a glass or plastic fiber optic conduction pathway.

7. A pacemaker in accordance with claim 1 wherein said photonic catheter comprises a fiber optic conduction pathway covered by a biocompatible covering.

8. A pacemaker in accordance with claim 7 wherein said biocompatible covering comprises a material from a group that includes silicone rubber, polyurethane and polyethylene.

9. A pacemaker in accordance with claim 1 further including a pacemaker tip electrode spaced from the distal end of said photonic catheter, and wherein said pulsing circuitry is housed in a ring electrode of said pacemaker connected to the distal end of said photonic catheter.

10. A pacemaker in accordance with claim 1 wherein said pulsing circuitry is partially housed at said distal end of said photonic catheter and also partially housed at said proximal end of said photonic catheter.

11. An MRI-compatible implantable cardiac pacemaker, said pacemaker comprising:

a first enclosure adapted to be implanted in a patient'"'"'s body at a location that is remote from the implanted patient'"'"'s heart;

a second enclosure unit adapted to be electrically connected to the implanted patient'"'"'s heart;

an optical conduction pathway disposed between said first and second enclosures;

an optical power source in said first enclosure operatively connected to a first end of said optical conduction pathway;

an optically driven electrical pulse generating system in said second enclosure operatively connected to a second end of said optical conduction pathway; and

said optical power source being adapted to provide a steady state optical power signal through said optical conduction pathway for use by said pulse generating system, and said pulse generating system being adapted to generate periodic electrical signals to stimulate the implanted patient'"'"'s heart.

12. A pacemaker in accordance with claim 11 wherein said first enclosure houses an electrical power supply and an electro-optical transducer adapted to convert the electrical signal output of said power supply to light energy for placement on said optical conduction pathway.

13. A pacemaker in accordance with claim 11 wherein said second enclosure houses an opto-electrical transducer adapted to receive said light energy from said optical conduction pathway and convert said energy to electrical energy, and a pulse generator powered by the electrical energy output of said opto-electrical transducer.

14. A pacemaker in accordance with claim 11 wherein said first enclosure comprises a hermetically sealed casing made of non-magnetic material.

15. A pacemaker in accordance with claim 14 wherein said non-magnetic material is selected from a group that includes titanium, platinum, and alloys thereof.

16. A pacemaker in accordance with claim 11 wherein said first enclosure houses a battery made from non-magnetic material, and an electro-optical transducer electrically connected to said battery and optically communicating with said first end of said optical conduction pathway.

17. A pacemaker in accordance with claim 16 wherein said electro-optical transducer comprises a light emitting diode.

18. A pacemaker in accordance with claim 11 wherein said optical conduction pathway comprises a fiber optic element.

19. A pacemaker in accordance with claim 18 wherein said optical conduction pathway further comprises a biocompatible covering over said fiber optic element.

20. A pacemaker in accordance with claim 19 wherein said covering comprises a jacket made from a group that includes silicone rubber, polyurethane and polyethylene.

21. A pacemaker in accordance with claim 19 wherein said covering has an outside diameter of about 5 millimeters.

22. A pacemaker in accordance with claim 11 wherein said second enclosure comprises a hermetically sealed casing made of non-magnetic metallic material.

23. A pacemaker in accordance with claim 22 wherein said non-magnetic material is selected from a group that includes titanium, platinum, and alloys thereof.

24. A pacemaker in accordance with claim 11 wherein said second enclosure houses an opto-electrical transducer adapted to optically communicate with said second end of said optical conduction pathway and electrically connected to a pulse generator.

25. A pacemaker in accordance with claim 24 wherein said opto-electrical transducer comprises a photo diode.

26. A pacemaker in accordance with claim 22 wherein said casing is generally cylindrical in shape.

27. A pacemaker in accordance with claim 26 wherein said optical conduction pathway is a fiber optic element having a biocompatible covering with an outside diameter, and wherein said casing has an outside diameter which is substantially co-equal to said covering outside diameter.

28. A pacemaker in accordance with claim 27 wherein the outside diameter of said casing and the outside diameter of said covering are each about 5 millimeters.

29. A pacemaker in accordance with claim 28 wherein said opto-electrical transducer and said pulse generator are carried in a matrix disposed within said casing.

30. A pacemaker in accordance with claim 29 wherein said casing functions as a ring electrode of a tip/ring portion of said pacemaker.

31. A pacemaker in accordance with claim 30 further including a third enclosure adapted to be inserted in the implanted patient'"'"'s heart and comprising a non-magnetic casing that electrically communicates with said pulse generator and which functions as a tip electrode of said tip/ring portion of said pacemaker.

32. A pacemaker in accordance with claim 31 wherein said optical conduction pathway is a fiber optic element having a biocompatible covering with an outside diameter, said casings of said second and third enclosures have an outside diameter which is substantially the same as said covering outside diameter, and said second and third enclosures are separated by a cylindrical length of the material used to form said biocompatible covering.

33. A pacemaker in accordance with claim 31 wherein said optical conduction pathway, said second enclosure and said third enclosure form a catheter extending from said first enclosure, said second enclosure and said third enclosure being generally cylindrical and being joined by a generally cylindrical length of a biocompatible material to form a catheter tip, and said optical conduction pathway being a fiber optic element having a biocompatible covering with an outside diameter substantially matching that of said second and third enclosures.

35. A pacemaker in accordance with claim 34, wherein said voltage source is electrically connected to an electro-optical transducer that is co-located with said voltage source in said first enclosure, said electro-optical transducer being adapted to produce a steady state optical signal that is fed into said optical system at a power level which is in the microwatt region.

36. A pacemaker in accordance with claim 35, wherein said pulse generator includes an opto-electrical transducer that receives said steady state optical signal and produces a steady state electrical signal having a voltage level of about 3.3 volts, said pulse generator further including an oscillator and an amplifier powered by said opto-electrical transducer and being adapted to produce electrical pulses of about 1 millisecond duration at a voltage level of about 3.3 volts and a current level of about 3 milliamperes for a total power output of about 10 milliwatts.

34. An MRI-compatible pacemaker, comprising:

a direct current voltage source housed in a first enclosure and adapted to produce a steady state electrical output signal;

a pulse generating circuit housed in a second enclosure and adapted to generate periodic heart-triggering pulses;

a cardiac electrode system adapted to electrically stimulate a heart in accordance with said heart-triggering pulses; and

an optical system adapted to transport optical signals representing said steady state electrical output signal from said first enclosure to said second enclosure.