Leadless tissue stimulation systems and methods

• US 20060136004A1
• Filed: 12/21/2005
• Published: 06/22/2006
• Est. Priority Date: 12/21/2004
• Status: Active Grant

• Current Assignee: EBR Systems, Inc.
• Original Assignee: EBR Systems, Inc.
• Inventors: Riley, Richard E., Cowan, Mark W., Brisken, Axel F., Echt, Debra S.
• Granted Patent: US 7,610,092 B2
• Time in Patent Office: Days
• US Class Current: 607/33
• CPC Class Codes: A61N 1/3621 for treating or preventing abnormally high heart rate
• CPC Class Codes: A61N 1/368 comprising more than one electrode co-operating with different heart regions A61N1/3622, A61N1/3627 take precedence
• CPC Class Codes: A61N 1/37205 Microstimulators, e.g. implantable through a cannula
• CPC Class Codes: A61N 1/37217 characterised by the communication link, e.g. acoustic or tactile
• CPC Class Codes: A61N 1/3756 Casings with electrodes thereon, e.g. leadless stimulators
• CPC Class Codes: A61N 1/3787 from an external energy source

Abstract

Systems including an implantable receiver-stimulator and an implantable controller-transmitter are used for leadless electrical stimulation of body tissues. Cardiac pacing and arrhythmia control is accomplished with one or more implantable receiver-stimulators and an external or implantable controller-transmitter. Systems are implanted by testing external or implantable devices at different tissue sites, observing physiologic and device responses, and selecting sites with preferred performance for implanting the systems. In these systems, a controller-transmitter is activated at a remote tissue location to transmit/deliver acoustic energy through the body to a receiver-stimulator at a target tissue location. The receiver-stimulator converts the acoustic energy to electrical energy for electrical stimulation of the body tissue. The tissue locations(s) can be optimized by moving either or both of the controller-transmitter and the receiver-stimulator to determine the best patient and device responses.

Claims

1. A method for stimulating cardiac muscle, said method comprising:

generating acoustic energy at a first implantation site; and

receiving said acoustic energy at a cardiac stimulation site, wherein said acoustic energy is converted into cardiac stimulation energy based on both energy and signal information included in the generated acoustic energy.

2. A method as in claim 1, wherein receiving comprises receiving the energy at at least two different cardiac stimulation sites.

3. A method as in claim 2, wherein the signal information sequentially activates two receiver-stimulators to stimulate two different cardiac sites sequentially.

4. A method as in claim 2, wherein the signal information simultaneously activates two receiver-stimulators to stimulate two different cardiac sites simultaneously.

5. A method as in claim 1, wherein the cardiac stimulation energy is delivered to prevent an abnormal cardiac rhythm.

6. A method as in claim 1, wherein the cardiac stimulation energy is delivered to terminate an abnormal cardiac rhythm.

7. A method as in claim 6, further comprising detecting cardiac tachyarrhythmia and delivering cardioversion/defibrillation energy.

8. A system for stimulating cardiac muscle, said system comprising:

an implantable acoustic controller-transmitter; and

an implantable acoustic receiver-stimulator having an electrode assembly adapted to be in direct contact with cardiac muscle tissue, wherein the controller-transmitter and receiver-stimulator are adapted to transmit and receive acoustic energy which provides both energy and signal information to the receiver-stimulator sufficient to stimulate said cardiac muscle tissue.

9. A system as in claim 8, wherein the receiver-stimulator comprises an acoustic receiver which receives acoustic energy and generates alternating current, means for converting the alternating current to a direct current or waveform to stimulate the cardiac tissue, and electrodes adapted to deliver the direct current or waveform to myocardial tissue.

10. A system as in claim 9, wherein the implantable receiver-stimulator is adapted to be placed and secured at any location within a cardiac chamber.

11. A system as in claim 9, wherein the implantable receiver-stimulator is adapted to be embedded and secured at any location within the myocardial tissue.

12. A system as in claim 9, wherein the implantable receiver-stimulator is adapted to be placed and secured at any location on the epicardial aspect of the heart.

13. A system as in claim 9, wherein the implantable receiver-stimulator is adapted to be placed and secured at any location within the coronary veins or arteries of the heart.

14. A system as in claim 13, wherein the implantable receiver-stimulator is placed on a stent.

15. A system as in claim 13, wherein the implantable receiver-stimulator is adapted to be secured between the outside of a stent wall and the inside of a vessel wall.

16. A system as in claim 8, wherein the implantable receiver-stimulator is adapted to be placed and secured to synchronize contraction between the left and right ventricles.

17. A system as in claim 8, wherein the implantable receiver-stimulator is adapted to be placed and secured to synchronize contraction within the left ventricle.

18. A system as in claim 8, wherein the implantable receiver-stimulator is adapted to be placed and secured to synchronize contraction between the left and right atria.

19. A system as in claim 8, wherein the implantable receiver-stimulator is adapted to be placed and secured to synchronize contraction between the atrium and the ventricle.

20. A system as in claim 8, wherein the implantable receiver-stimulator is adapted to be placed and secured to synchronize contraction between multiple sites within the heart.

21. A system as in claim 8, wherein the controller-transmitter is adapted to be placed externally on the patient to deliver energy to the implantable acoustic receiver-stimulator.

22. A system as in claim 8, wherein the controller-transmitter comprises a power source, control and timing circuitry to provide a pacing signal, means for converting the pacing signal to an acoustic energy signal, and means for transmitting the acoustic energy signal to the receiver-stimulator.

23. A system as in claim 22, wherein control and timing circuitry includes one or more means for sensing physiologic variables or non-physiologic variables in order to adjust timing of stimulation.

24. A system as in claim 23, wherein sensing non-physiologic variables includes detecting a pacemaker pacing output and timing the pacing signal for stimulation from that detection in order to synchronize the cardiac stimulation from the implantable receiver-stimulator with an implanted pacemaker.

25. A system as in claim 23, wherein means for sensing physiologic variables includes a blood pressure sensor.

26. A system as in claim 23 or 24 wherein means for sensing physiologic or non-physiologic variables includes processing electrogram signals from electrodes in contact with tissue located on the exterior surface of the controller-transmitter.

27. A system as in claim 26, wherein the electrogram signal processor is adapted to detect intrinsic cardiac beats.

28. A system as in claim 26, wherein the electrogram signal processor is adapted to detect pacemaker pacing output.

29. A system as in claim 26, wherein the electrogram signal processor is adapted to detect non-intrinsic cardiac beats initiated by pacemaker pacing outputs.

30. A system as in claim 26, wherein the electrogram signal processor is adapted to detect tachyarrhythmia.

31. A system as in claim 27, wherein the control circuitry can selectively pace and/or defibrillate after detecting tachyarrhythmia.

32. A system as in claim 23, wherein means for sensing physiologic variables includes an accelerometer for sensing body movement activity.

33. A system as in claim 23, wherein means for sensing physiologic variables includes processing heart sounds.

34. A system as in claim 23, wherein means for sensing physiologic variables includes processing impedance changes in the body related to respiration cycles or lung edema.

35. A system as in claim 23, wherein means for sensing physiologic variables includes processing body temperature.

36. A system as in claim 24, wherein sensing a pacemaker pacing output includes connecting a cable from the controller-transmitter to a pacing output channel of an implanted pacemaker and detecting the occurrence of the pacemaker pacing output from the cable.

37. A system as in claim 8, further comprising at least one additional receiver-stimulator device.

38. A system as in claim 37, wherein the system is programmed to activate the receiver-stimulator devices sequentially.

39. A system as in claim 37, wherein the system is programmed to activate the receiver-stimulator devices simultaneously.

40. A system as in claim 8, wherein the implantable acoustic controller-transmitter includes control circuitry for a conventional pacemaker and is adapted to utilize electrode-tipped transvenous leads placed into the right atrium and/or right ventricle for conventional electrical pacing.

41. A system as in claim 40, wherein the implantable controller-transmitter/pacemaker combination comprises a power source, control and timing circuitry to provide multiple pacing signals, means for amplifying and applying at least one conventional pacing output signal to cardiac muscle through electrodes on the transvenous leads, plus means for converting at least one pacing signal to an acoustic energy signal, and means for transmitting the acoustic energy signal to the receiver-stimulator.

42. A system for stimulating cardiac muscle as in claim 8, said system comprising:

an implantable acoustic controller-transmitter; and

an implantable acoustic receiver-stimulator wherein the transmitter and receiver-stimulator are adapted to transmit and receive acoustic energy wherein the frequency of the acoustic energy is between 20 kHz and 10 MHz.

43. A system as in claim 42, wherein the frequency of the acoustic energy is most preferably between 200 kHz and 500 kHz.

44. A method for stimulating cardiac muscle, said method comprising:

generating acoustic energy at a first implantation site;

receiving said acoustic energy at a cardiac stimulation site, wherein said acoustic energy is converted into cardiac stimulation energy based on both energy and signal information included in the generated acoustic energy; and

synchronizing the stimulation with a cardiac pacemaker.

45. A method as in claim 44, wherein stimulating cardiac muscle provides left ventricular stimulation synchronously with right ventricular pacemaker stimulation.

46. A method as in claim 44, wherein stimulating cardiac muscle provides right ventricular stimulation synchronously with left ventricular pacemaker stimulation.

47. A method as in claim 44, wherein synchronizing the cardiac muscle stimulation is performed by detection of a pacemaker pacing output signal.

48. A method as in claim 47, wherein the detection of a cardiac pacemaker pacing output signal is performed by sensing atrial and/or ventricular pacing signal artifacts from an electrogram signal.

49. A method as in claim 47, wherein the detection of a pacemaker pacing output signal is performed through a direct connection to a pacing output of a cardiac pacemaker.

50. A method as in claim 47, wherein the detection of a pacemaker pacing output signal is performed through a direct communication connection to a cardiac pacemaker.

51. A method as in claim 44, wherein synchronizing the stimulation is performed by detecting intrinsic or non-intrinsic cardiac beats from an electrogram signal.

52. A method as in claim 44, wherein synchronizing the stimulation is performed by detecting any combination of intrinsic cardiac beats, non-intrinsic cardiac beats, and pacing artifacts from an electrogram signal.

53. A system for the delivery of antitachycardia pacing to a patient'"'"'s heart, comprising:

one or more acoustic receiver-stimulators having an electrode assembly adapted to be implanted in direct contact with cardiac tissue; and

an acoustic controller-transmitter, wherein the controller-transmitter and receiver-stimulator are adapted to transmit and receive acoustic energy which provides both energy and signal information to the receiver-stimulator sufficient to stimulate the heart.

54. A system as in claim 53 wherein the receiver-stimulator comprises an acoustic receiver which receives acoustic energy and generates alternating current, means for converting the alternating current to a direct current or waveform to stimulate the cardiac tissue, and electrodes adapted to deliver the direct current or waveform to myocardial tissue.

55. A system as in claim 53, wherein the controller-transmitter is implantable in a subcutaneous region that directs acoustic energy to the receiver-stimulator.

56. A system as in claim 53, wherein the implantable receiver-stimulator is adapted to be placed and secured at a location that optimally terminates the tachyarrhythmia.

57. A system as in claim 55, wherein the implantable receiver-stimulator is adapted to be placed and secured at a location within the tissue which is in the conduction pathway of the tachyarrhythmia.

58. A system as in claim 53, wherein the implantable receiver-stimulator is adapted to be placed and secured at a location that optimally prevents a tachyarrhythmia.

59. A system as in claim 53, wherein the implantable receiver-stimulator is adapted to be placed and secured at a location within the tissue which is in the normal conduction pathway of the heart.

60. A system as in claim 53, where in the implantable receiver-stimulator is placed and secured at any location within a cardiac chamber.

61. A system as in claim 53, where in the implantable receiver-stimulator is placed and secured at any location within the myocardial tissue.

62. A system as in claim 53, wherein the implantable receiver-stimulator is placed and secured at a location on the epicardial aspects of the heart.

63. A system as in claim 53, wherein two or more receiver-stimulator are placed and secured in locations that optimally prevent or terminate the tachyarrhythmia.

64. A system as in claim 53 wherein the controller-transmitter is adapted to contain circuitry to sense an electrocardiogram from electrodes mounted on the controller-transmitter device.

65. A system as in claim 64, wherein the controller-transmitter processes the electrocardiogram to determine the presence or absence of a tachyarrhythmia.

66. A system as in claim 65, wherein the determination of the presence or absence of a tachyarrhythmia is based on heart rate or electrogram waveform morphology.

67. A system as in claim 53, wherein the at least one of the acoustic receiver-stimulator(s) and the acoustic controller-transmitter is adapted to deliver cardioversion/defibrillation energy when tachyarrhythmia is detected.

68. A method for selecting and optimizing the implanted locations of a controller-transmitter device and a receiver-stimulator device, said method comprising;

positioning a controller-transmitter at a remote tissue location;

positioning a receiver-stimulator at a target tissue location;

activating the controller-transmitter to deliver acoustic energy to the receiver-stimulator so that said receiver-stimulator delivers electrical energy into the target tissue location;

observing a first response;

repositioning at least one of the controller-transmitter and the receiver-stimulator;

observing a subsequent response;

comparing the first and subsequent response(s) to determine which controller-transmitter and/or receiver-stimulator positions(s) is/are better; and

implanting a controller-transmitter device and a receiver-stimulator device at respective selected positions.

69. A method as in claim 68, wherein the controller-transmitter used for positioning is an externally applied device used to select the site for an implantable controller-transmitter device.

70. A method as in claim 68, wherein the receiver-stimulator used for positioning is a temporarily applied device used to select the site for an implantable receiver-stimulator device.

71. A method as in claim 68, wherein the response is a patient response.

72. A method as in claim 68, wherein the response is a device measurement.

73. A method as in claim 72, wherein the device measurement is the electrical output amplitude of the receiver-stimulator.

74. A method as in claim 72, wherein the device measurement is the acoustic output amplitude of the controller-transmitter.

75. A method as in claim 68, wherein the device measurement is efficiency of energy transmission from the controller-transmitter to the receiver-stimulator.

76. A method as in claim 68, wherein the target tissue location is cardiac tissue, the remote tissue location is over the heart and sternum or ribcage, and the observed patient response is heart function.

77. A method as in claim 68, wherein the target tissue location is cardiac tissue, the remote tissue location is over the heart and sternum or ribcage, and the observed patient response is electrocardiographic.

78. A method as in claim 68, wherein the target tissue location is brain tissue, the remote tissue location is in or over the cranium, and the patient response is electroencephalagraphic.

79. A method as in claim 68, wherein the target tissue location is at a bone fracture, the remote tissue location is over the bone, and the device measurement is electric energy delivery to the bone.

80. A method as in claim 68, wherein the target tissue location is held constant at the predetermined site while only the remote tissue location is varied.

81. A method as in claim 68, wherein the remote tissue location is held constant at a predetermined site while only the target tissue location is varied.

82. A method as in claim 68, wherein both the target tissue location and the remote tissue location are varied.

83. A system for optimizing placement of implantable devices for stimulating tissue, said system comprising:

an acoustic controller-transmitter; and

a delivery system containing an acoustic receiver-stimulator device.

84. A system as in claim 83, wherein the acoustic receiver-stimulator contained in the delivery system can be mechanically deployed from the delivery system in order to be implanted into the tissue.

85. A system as in claim 83, wherein the delivery system is an acoustic receiver-stimulator temporarily affixed to a catheter.

86. A system as in claim 85, wherein the catheter is steerable.

87. A system as in claim 85, wherein the delivery system includes operating the catheter in a guiding sheath.

88. A system as in claim 87, wherein the guiding sheath is steerable.

89. A system as in claim 83, wherein the acoustic receiver-stimulator is permanently affixed to a catheter.

90. A system as in claim 89, wherein the catheter is steerable.

91. A system as in claim 89, wherein the catheter is operated through a guiding sheath.

92. A system as in claim 91, wherein the guiding sheath is steerable.

93. A system as in claim 83, wherein the controller-transmitter is an external unit under manual control.

94. A system as in claim 83, wherein the controller-transmitter is an implanted device.

95. A system as in claim 94, wherein the implanted controller-transmitter is manually controlled through communication with an external programmer unit.