Method and apparatus of acoustic communication for implantable medical device

• US 20060009818A1
• Filed: 07/09/2004
• Published: 01/12/2006
• Est. Priority Date: 07/09/2004
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Von Arx, Jeffrey A., Mazar, Scott T., Chavan, Abhi
• Granted Patent: US 7,489,967 B2
• Time in Patent Office: Days
• US Class Current: 607/60
• CPC Class Codes: A61B 5/0028 Body tissue as transmission medium, i.e. transmission systems where the medium is the human body
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61N 1/37217 characterised by the communication link, e.g. acoustic or tactile
• CPC Class Codes: A61N 1/3727 characterised by the modulation technique
• CPC Class Codes: A61N 1/37288 Communication to several implantable medical devices within one patient

Abstract

An implantable medical device includes an acoustic transducer for intra-body communication with another medical device via an acoustic couple. The acoustic transducer includes one or more piezoelectric transducers. In one embodiment, an implantable medical device housing contains a cardiac rhythm management (CRM) device and an acoustic communication circuit. The acoustic transducer is electrically connected to the acoustic communication circuit to function as an acoustic coupler and physically fastened to a wall of the implantable housing, directly or via a supporting structure.

Claims

1. An implantable medical device, comprising:

a cardiac rhythm management (CRM) device;

an acoustic communication circuit coupled to the CRM device, the acoustic communication circuit including at least one of a data transmitter and a data receiver;

an acoustic transducer coupled to the acoustic communication circuit, the acoustic transducer configured to be an acoustic coupler for acoustic communication; and

an implantable housing including a wall forming a chamber to contain the CRM device and the acoustic communication circuit.

2. The implantable medical device of claim 1, wherein the CRM device comprises one or more of a pacemaker circuit and a cardioversion/defibrillation circuit.

3. The implantable medical device of claim 1, wherein the CRM device comprises a monitoring device sensing one or more physiologic signals.

4. The implantable medical device of claim 1, wherein the CRM device comprises a drug delivery device.

5. The implantable medical device of claim 1, wherein the acoustic transducer is fastened to the wall of the implantable housing.

6. The implantable medical device of claim 5, wherein the wall of the implantable housing comprises an interior surface and an exterior surface, the interior surface facing the chamber, and wherein the acoustic transducer is fastened to the interior surface.

7. The implantable medical device of claim 5, wherein the wall of the implantable housing comprises an interior surface and an exterior surface, the interior surface facing the chamber, and wherein the acoustic transducer is fastened to the exterior surface.

8. The implantable medical device of claim 7, further comprising a diaphragm connected to the exterior surface to form a cavity between the diaphragm and the exterior surface, the cavity filled with fluid, wherein the acoustic transducer is fastened to the exterior surface within the cavity.

9. The implantable medical device of claim 1, further comprising a diaphragm connected to the wall of the implantable housing, and wherein the acoustic transducer is fastened to the diaphragm.

10. The implantable medical device of claim 9, wherein the wall of the implantable housing comprises an interior surface and an exterior surface, the interior surface facing the chamber, wherein the diaphragm is connected to the exterior surface to form a cavity between the diaphragm and the exterior surface, and wherein the acoustic transducer is fastened to the diaphragm within the cavity.

11. The implantable medical device of claim 9, wherein the wall of the implantable housing comprises an interior surface and an exterior surface, the interior surface facing the chamber, wherein the wall comprises a hole over which the diaphragm is connected to the wall, and wherein the acoustic transducer is fastened to the diaphragm within the chamber.

12. The implantable medical device of claim 9, wherein the wall of the implantable housing comprises an interior surface and an exterior surface, the interior surface facing the chamber, wherein the wall comprises a thinned portion forming the diaphragm, and wherein the acoustic transducer is fastened to the diaphragm within the chamber.

13. The implantable medical device of claim 9, wherein the diaphragm is configured to have a resonant frequency approximately equal to a carrier frequency used in the acoustic communication.

14. The implantable medical device of claim 13, wherein a material having a predetermined stiffness is coated onto the diaphragm.

15. The implantable medical device of claim 9, wherein the implantable housing and the diaphragm are each made of a metal.

16. The implantable medical device of claim 15, wherein the implantable housing and the diaphragm are each made of titanium.

17. The implantable medical device of claim 15, wherein the implantable housing is made of a first type metal, and the diaphragm is made of a second type metal different from the first type metal.

18. The implantable medical device of claim 1, wherein the acoustic transducer is made of a piezoelectric material.

19. The implantable medical device of claim 18, wherein the acoustic transducer is made of polyvinylidene fluoride (PVDF).

20. The implantable medical device of claim 18, wherein the acoustic transducer is made of piezoelectric ceramic.

21. An implantable medical device, comprising:

one or more of a sensing circuit to sense one or more physiologic signals and a therapy delivery circuit;

a plurality of acoustic transducers configured to be an acoustic coupler for acoustic communication;

an acoustic communication circuit coupled to the one or more of the sensing circuit and the therapy delivery circuit, the acoustic communication circuit including a transducer interface circuit coupled to the plurality of acoustic transducers; and

an implantable housing including a wall forming a chamber to contain the one or more of the sensing circuit and the therapy delivery circuit and the acoustic communication circuit.

22. The implantable medical device of claim 21, wherein the plurality of acoustic transducers are configured to be an approximately omni-directional acoustic coupler for the acoustic communication.

23. The implantable medical device of claim 21, wherein the transducer interface circuit comprises a programmable interconnection network adapted to provide programmable interconnections among acoustic transducers of the plurality of acoustic transducers.

24. The implantable medical device of claim 23, wherein the acoustic communication circuit comprises a transmitter circuit and a receiver circuit, and wherein the programmable interconnection network is programmed to connect the acoustic transducers in parallel when the transmitter circuit is transmitting a signal and to connect the acoustic transducers in series when the transmitter circuit is receiving a signal.

25. The implantable medical device of claim 21, wherein the plurality of acoustic transducers comprises stacked piezoelectric transducers fastened to the wall of the implantable housing.

26. The implantable medical device of claim 21, wherein the plurality of acoustic transducers comprises piezoelectric transducers each fastened to the wall of the implantable housing.

27. The implantable medical device of claim 26, wherein the plurality of acoustic transducers comprises a microelectromechanical acoustic transducer array (MEMS-UTA).

28. The implantable medical device of claim 21, wherein the transducer interface circuit comprises a steering circuit adapted to control a directionality and an effective orientation of the acoustic coupler.

29. A cardiac rhythm management (CRM) system, comprising:

a CRM device;

an acoustic transducer configured to be an acoustic coupler for acoustic communication;

an acoustic communication circuit coupled to the CRM device, the acoustic communication circuit including a data receiver coupled to the acoustic transducer, the data receiver adapted to receive an incoming acoustic signal including an first carrier signal modulated by incoming data; and

an implantable housing to contain the CRM device and the acoustic communication circuit,

wherein the acoustic transducer is fastened to the implantable housing.

30. The CRM system of claim 29, wherein the acoustic communication circuit further comprises a data transmitter circuit, coupled to the acoustic transducer, to transmit an outgoing acoustic signal including a second carrier signal modulated by outgoing data.

31. The CRM system of claim 30, wherein the first carrier signal and the second carrier signal each have a carrier frequency of up to approximately 5 MHz.

32. The CRM system of claim 31, wherein the first carrier signal and the second carrier signal each have a carrier frequency in a range of approximately 30 kHz to 60 kHz.

33. The CRM system of claim 31, wherein the first carrier signal and the second carrier signal each have a carrier frequency in an ultrasonic range.

34. The CRM system of claim 30, wherein the data receiver circuit comprises an amplitude-shift keying (ASK) demodulator, and the data transmitter circuit comprises:

a carrier generator to generate the second carrier signal; and

an amplitude-shift keying (ASK) modulator, coupled to the carrier generator and the acoustic transducer, to modulate the second carrier signal with the outgoing data.

35. The CRM system of claim 34, wherein the acoustic carrier generator is a variable-frequency waveform generator programmable for two or more carrier frequencies for the second carrier signal.

36. The CRM system of claim 35, wherein the data receiver circuit comprises an error detector, coupled to the ASK demodulator, to detect an error rate of from the demodulated incoming acoustic signal.

37. The CRM system of claim 36, wherein the acoustic communication circuit further comprises a frequency selection circuit to select a carrier frequency from the two or more carrier frequencies for the second carrier signal based on the detected error rate.

38. The CRM system of claim 30, further comprising a rechargeable battery contained in the implantable housing, and wherein the acoustic communication circuit further comprises a power receiver coupled to the acoustic transducer and the rechargeable battery, the power receiver adapted to recover a direct current (dc) power from the acoustic signals to recharge the rechargeable battery.

39. A cardiac rhythm management (CRM) system, comprising:

a first implantable medical device including;

a CRM device;

an acoustic communication circuit coupled to the CRM device; and

an acoustic transducer coupled to the acoustic communication circuit,

the acoustic transducer configured to be an acoustic coupler for an acoustic couple adapted for data communication; and

a second medical device communicatively coupled to the first implantable medical device via the acoustic couple.

40. The CRM system of claim 39, wherein the CRM device comprises one or more of a pacemaker circuit and a cardioversion/defibrillation circuit.

41. The CRM system of claim 39, wherein the CRM device comprises a cardiac resynchronization therapy (CRT) device.

42. The CRM system of claim 39, wherein the CRM device comprises a cardiac remodeling control therapy (RCT) device.

43. The CRM system of claim 39, wherein the second medical device comprises a second implantable medical device.

44. The CRM system of claim 43, wherein the second implantable medical device comprises an implantable sensing module adapted to sense at least one physiological signal.

45. The CRM system of claim 44, wherein the implantable sensing module comprises a pressure sensing module.

46. The CRM system of claim 39, wherein the second medical device comprises a medical device including at least a portion configured for skin attachment.

47. The CRM system of claim 46, wherein the second medical device comprises a CRM device programmer adapted to program the first implantable medical device.

48. An implantable medical device, comprising:

at least one of a monitoring device to sense one or more physiologic signals and a therapy delivery device;

an acoustic communication circuit coupled to the at least one of the monitoring device and the therapy delivery device;

an acoustic transducer coupled to the acoustic communication circuit, the acoustic transducer configured to be an acoustic coupler for acoustic communication; and

an implantable housing including a wall forming a chamber to contain the at least one of the monitoring device and the therapy delivery device and the acoustic communication circuit,

wherein the acoustic transducer is fastened to the wall of the implantable housing.

49. The implantable medical device of claim 48, further comprising a monitoring device coupled to the acoustic transducer and contained in the implantable housing, the monitoring device including one or more sensors to sense one or more physiological signals.

50. The implantable medical device of claim 48, further comprising an electrical stimulation device coupled to the acoustic transducer and contained in the implantable housing.

51. The implantable medical device of claim 48, further comprising a drug delivery device coupled to the acoustic transducer and contained in the implantable housing.

52. The implantable medical device of claim 48, further comprising a diaphragm connected to the wall of the implantable housing to form a cavity between the diaphragm and the wall of the implantable housing, wherein the acoustic transducer is fastened to the wall within the cavity.

53. An implantable medical device, comprising:

at least one of a monitoring device to sense one or more physiologic signals and a therapy delivery device;

an acoustic communication circuit coupled to the at least one of the monitoring device and the therapy delivery device;

an acoustic transducer coupled to the acoustic communication circuit, the acoustic transducer configured to be an acoustic coupler for acoustic communication;

an implantable housing including a wall forming a chamber to contain the at least one of the monitoring device and the therapy delivery device and the acoustic communication circuit; and

a diaphragm connected to the wall of the implantable housing,

wherein the acoustic transducer is fastened to the diaphragm.

54. The implantable medical device of claim 53, further comprising a monitoring device coupled to the acoustic transducer and contained in the implantable housing, the monitoring device including one or more sensors to sense one or more physiological signals.

55. The implantable medical device of claim 53, further comprising an electrical stimulation device coupled to the acoustic transducer and contained in the implantable housing.

56. The implantable medical device of claim 53, further comprising a drug delivery device coupled to the acoustic transducer and contained in the implantable housing.

57. The implantable medical device of claim 53, wherein the diaphragm is configured to have a resonant frequency approximately equal to a carrier frequency used in the acoustic communication.

58. A method for making an implantable medical device, the method comprising:

providing an cardiac rhythm management (CRM) device with a communication circuit;

providing an implantable housing including a wall forming a chamber;

connecting an acoustic transducer functioning as an acoustic coupler to the communication circuit;

connecting an acoustic coupler assembly including the acoustic transducer to the wall; and

encapsulating the CRM device and the communications circuit in the chamber.

59. The method of claim 58, wherein connecting the acoustic coupler assembly to the wall comprises fastening the acoustic transducer to the wall.

60. The method of claim 59, wherein fastening the acoustic transducer to the wall comprises gluing the acoustic transducer to the wall.

61. The method of claim 59, wherein fastening the acoustic transducer to the wall comprises welding the acoustic transducer to the wall.

62. The method of claim 59, wherein fastening the acoustic transducer to the wall comprises soldering the acoustic transducer to the wall.

63. The method of claim 59, wherein fastening the acoustic transducer to the wall comprises bracing the acoustic transducer to the wall.

64. The method of claim 59, further comprising thinning a portion of the wall, and wherein fastening the acoustic transducer to the wall comprises fastening the acoustic transducer to the thinned portion of the wall.

65. The method of claim 59, wherein the wall of the implantable housing comprises an interior surface and an exterior surface, the interior surface facing the chamber, and wherein connecting the acoustic coupler assembly including the acoustic transducer to the wall comprises fastening the acoustic transducer to the interior surface.

66. The method of claim 59, wherein the wall of the implantable housing comprises an interior surface and an exterior surface, the interior surface facing the chamber, and wherein connecting the acoustic coupler assembly including the acoustic transducer to the wall comprises fastening the acoustic transducer to the exterior surface.

67. The method of claim 66, further comprising:

connecting a diaphragm to the exterior surface to form a cavity between the diaphragm and the exterior surface; and

filling the cavity with fluid.

68. The method of claim 58, wherein connecting the acoustic coupler assembly to the wall comprises:

connecting a diaphragm to the wall; and

fastening the acoustic transducer to the diaphragm.

69. The method of claim 68, wherein the wall of the implantable housing comprises an interior surface and an exterior surface, the interior surface facing the chamber, and wherein connecting the diaphragm to the wall comprises connecting the diaphragm to the exterior surface to form a cavity between the diaphragm and the exterior surface, and fastening the acoustic transducer to the diaphragm comprises fastening the acoustic transducer to a surface of the diaphragm within the cavity.

70. The method of claim 68, further comprising providing a hole on the wall, and wherein connecting the diaphragm to the wall comprises connecting the diaphragm to the wall to cover the hole.

71. The method of claim 58, wherein connecting the acoustic transducer to the communication circuit comprises connecting a piezoelectric transducer array to the communication circuit, the piezoelectric transducer array including two or more piezoelectric transducers.

72. The method of claim 71, wherein connecting the piezoelectric transducer array to the communication circuit comprises stacking the two or more piezoelectric transducers, and wherein connecting the acoustic coupler assembly to the wall comprises fastening the stacked two or more piezoelectric transducers to the wall.

73. The method of claim 71, wherein connecting the acoustic coupler assembly to the wall comprises fastening each piezoelectric transducer of the two or more piezoelectric transducers to the wall.

74. The method of claim 71, wherein connecting the acoustic transducer to the communication circuit comprises providing programmable interconnections for the two or more piezoelectric transducers.

75. The method of claim 74, further comprising providing a transducer interface circuit to control a directionality and an effective orientation of the acoustic transducer functioning as the acoustic coupler.

76. The method of claim 75, wherein providing the transducer interface circuit comprises providing a programmable phase delay to each piezoelectric transducer of the two or more piezoelectric transducers.