MRI-compatible pacemaker with pulse carrying photonic catheter providing VOO functionality

• US 20020116028A1
• 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, Connelly, Patrick
• Application Number:
  US09/864,944
• Publication Number:
  US 20020116028A1
• 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 and a pulse generator housed at the proximal end of a photonic catheter in a first enclosure. Electrical pulses output by the pulse generator are 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 an opto-electrical transducer that converts the optical pulses to electrical pulses and delivers them to bipolar heart electrodes. One of the electrodes may comprise the second enclosure housing the opto-electrical transducer and the other electrode can be 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.

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 said proximal end of said photonic catheter;

first power conversion means for converting the output of said pulsing circuitry 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;

electrodes operatively connected to said second power conversion means for receiving said electrical energy and delivering it to cardiac tissue to which said electrodes are adapted to be connected.

2. A pacemaker in accordance with claim 1, wherein said electrical power source, said pulsing circuitry, and said first power conversion means are housed in a first enclosure and said second power conversion means is housed in a second enclosure, said first and second enclosures being 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 second power conversion means 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 tip and ring electrode are made of non-magnetic metallic material.

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 pulse generating system in said first enclosure operatively connected to a first end of said optical conduction pathway;

an opto-electrical transducer in said second enclosure operatively connected to a second end of said optical conduction pathway;

said optical pulse generating system being adapted to provide periodic optical pulse signals through said optical conduction pathway to said opto-electrical transducer, and said opto-electrical transducer being adapted to convert said optical pulse signals into electrical pulse signals; and

electrodes operatively connected to said opto-electrical transducer for receiving said electrical pulse signals and delivering them to said patient'"'"'s heart.

12. A pacemaker in accordance with claim 11 wherein said optical pulse generating system includes an electrical pulse generator and an electro-optical transducer adapted to convert the electrical signal output of said electrical pulse generating system to said optical pulse signals for placement on said optical conduction pathway.

13. A pacemaker in accordance with claim 11 wherein said opto-electrical transducer includes a photo diode circuit.

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, a pulse generator powered by said battery, and an electro-optical transducer electrically connected to said pulse generator 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 22 wherein said casing is generally cylindrical in shape.

25. A pacemaker in accordance with claim 24 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 coequal to said covering outside diameter.

26. A pacemaker in accordance with claim 25 wherein the outside diameter of said casing and the outside diameter of said covering are each about 5 millimeters.

27. A pacemaker in accordance with claim 26 wherein said opto-electrical transducer is carried in a matrix disposed within said casing.

28. A pacemaker in accordance with claim 27 wherein said casing functions as a ring electrode member of said electrodes.

29. A pacemaker in accordance with claim 28 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 opto-electrical transducer and which functions as a tip electrode member of said electrodes.

30. A pacemaker in accordance with claim 29 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.

31. A pacemaker in accordance with claim 29 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.

32. An MRI-compatible pacemaker, comprising:

a pulse generating circuit housed in a first 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 heart-triggering pulses from said first enclosure to said cardiac electrode system.

33. A pacemaker in accordance with claim 32, wherein said pulse generating circuit is electrically connected to an electro-optical transducer that is co-located with said pulse generating circuit in said first enclosure, said electro-optical transducer being adapted to produce an optical pulse signal that is fed into said optical system at a power level which is in the milliwatt region.

34. A pacemaker in accordance with claim 33, wherein said cardiac electrode system includes an opto-electrical transducer that receives said optical pulse signal and produces 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.