OPTIMIZING ENERGY TRANSMISSION IN A LEADLESS TISSUE STIMULATION SYSTEM

• US 20080294208A1
• Filed: 05/23/2007
• Published: 11/27/2008
• Est. Priority Date: 05/23/2007
• Status: Active Grant

• Current Assignee: EBR Systems, Inc.
• Original Assignee: EBR Systems, Inc.
• Inventors: Cowan, Mark W., Brisken, Axel F., Fowler, Robert, Brennan, James, WILLIS, N. PARKER, Pare, Michael
• Granted Patent: US 8,718,773 B2
• Time in Patent Office: Days
• US Class Current: 607/3
• CPC Class Codes: A61B 5/0093 Detecting, measuring or recording by applying one single type of energy and measuring its conversion into another type of energy
• CPC Class Codes: A61N 1/37217 characterised by the communication link, e.g. acoustic or tactile
• CPC Class Codes: A61N 1/37235 Aspects of the external programmer
• CPC Class Codes: A61N 1/37252 Details of algorithms or data aspects of communication system, e.g. handshaking, transmitting specific data or segmenting data
• 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

Method and systems for optimizing acoustic energy transmission in implantable devices are disclosed. Transducer elements transmit acoustic locator signals towards a receiver assembly, and the receiver responds with a location signal. The location signal can reveal information related to the location of the receiver and the efficiency of the transmitted acoustic beam received by the receiver. This information enables the transmitter to target the receiver and optimize the acoustic energy transfer between the transmitter and the receiver. The energy can be used for therapeutic purposes, for example, stimulating tissue or for diagnostic purposes.

Claims

1. A system for focusing acoustic energy into a human body comprising:

an array of acoustic transducers configured to transmit acoustic energy into the body;

circuitry for focusing the acoustic energy at specific regions in the body;

an acoustic receiver adapted to receive the acoustic energy and convert the acoustic energy into electrical energy;

a pair of electrodes connected to the acoustic receiver and adapted to transfer the electrical energy to the body;

wherein the circuitry is further configured to detect the electrical energy transferred through the body by these electrodes to determine whether the acoustic energy is focused on the acoustic receiver.

47. The system of claim 1, wherein the circuitry further comprises one or more pairs of electrodes that are configured to determine whether the acoustic energy is focused on the acoustic receiver.

48. The system of claim 47, wherein the circuitry is further configured for sequentially transmitting the acoustic energy.

2. A system for stimulating tissue comprising:

an implantable acoustic controller-transmitter comprising an array of acoustic transducers configured to transmit focused acoustic energy;

one or more implantable acoustic receiver-stimulators adapted to receive the acoustic energy and convert the acoustic energy into electrical energy;

wherein the receiver-stimulator further comprises two electrodes configured to be in electrical communication with the tissue; and

the electrical energy is delivered between the two electrodes; and

wherein the controller-transmitter is configured to determine the location of one or more of the receiver-stimulators relative to the controller-transmitter so that the controller-transmitter can direct the focused acoustic energy to one or more of the receiver-stimulators.

3. A system for stimulating tissue comprising:

an implantable acoustic controller-transmitter comprising an array of acoustic transducers configured to transmit acoustic energy into the tissue;

one or more implantable acoustic receiver-stimulators adapted to receive the acoustic energy and convert the acoustic energy into electrical energy; and

a first electrode assembly connected to the receiver-stimulator so as to receive the electrical energy and adapted to be in electrical communication with the tissue,

wherein the controller-transmitter is configured to transmit an acoustic locator signal towards the receiver-stimulator, and the receiver-stimulator is configured to generate a location signal in response to the locator signal.

4. The system of claim 3, wherein the controller-transmitter is further configured to detect the location signal;

and the transducer array is configured to sequentially steer the acoustic beam to transmit the locator signal to regions of the tissue until the location signal is detected or a preset time limit has been reached.

5. The system of claim 4, wherein the transducer array is configured to transmit the locator signal as a focused acoustic beam.

6. The system of claim 4, wherein the controller-transmitter is further configured to adjust the transducer array to transmit focused acoustic energy to the region of the tissue associated with detecting the location signal.

7. The system of claim 6, wherein the acoustic energy is sufficient to stimulate tissue.

8. The system of claim 7, wherein the tissue is cardiac tissue.

9. The system of claim 3, wherein the location signal is an electrical output applied to the first electrode assembly.

10. The system of claim 9, further comprising a sensing circuit, and a second electrode assembly adapted to be in electrical communication with the body, wherein the location signal is detected by the sensing circuit.

11. The system of claim 10, wherein the sensing circuit and the second electrode assembly are located on the implantable controller-transmitter.

12. The system of claim 10, wherein the sensing circuit is located on a separate implantable device.

13. The system of claim 10, wherein the sensing circuit and the second electrode assembly are located on a device with the second electrode assembly in electrical communication with the external surface of the body.

14. The system of claim 10, wherein the sensing circuit is a spike detector circuit.

15. The system of claim 10, wherein the sensing circuit and the second electrode assembly comprise a spike detector assembly on the implantable controller-transmitter.

16. The system of claim 10, wherein the locator signal is focused acoustic energy and the detected electrical output indicates that the transducer array is focused on the receiver-stimulator.

17. The system of claim 15, comprising circuitry configured to characterize the electrical output detected by the spike detector assembly using one or more parameters including amplitude and polarity to determine the location of the receiver-stimulator;

and adjust the transducer array based on the parameters to focus acoustic energy towards the receiver-stimulator.

18. The system of claim 17, wherein optimal energy transmission is indicated by the electrical output being above a pre-determined threshold or detection within a pre-determined time frame.

19. The system of claim 18, wherein the transducer array is further sequentially adjusted to transmit focused acoustic energy as locator signals towards a sequence of regions of the tissue and the detection of the electrical output by the spike detector assembly following any one of the transmissions indicates that the acoustic energy is focused on the receiver-stimulator.

20. The system of claim 18, wherein the electrical output is less than the amplitude required to stimulate tissue, and wherein the tissue is cardiac tissue.

21. The system of claim 18, wherein the electrical output is sufficient to stimulate tissue, and wherein the tissue is cardiac tissue.

49. The system of claim 5, wherein the controller-transmitter is further configured to adjust the transducer array to transmit focused acoustic energy to the region of the tissue associated with detecting the location signal.

50. The system of claim 49, wherein the acoustic energy is sufficient to stimulate tissue.

51. The system of claim 50, wherein the tissue is cardiac tissue.

22. A system for efficiently transferring acoustic energy comprising:

an implantable acoustic controller-transmitter comprising an acoustic transducer array configured to transmit acoustic energy into tissue;

an implantable acoustic receiver-converter adapted to receive the acoustic energy and convert the acoustic energy to electrical energy, wherein the controller-transmitter is configured to transmit an acoustic locator signal towards the receiver-converter, and the receiver-converter is configured to generate a location signal in response to the locator signal.

23. The system of claim 22, wherein the transducer array is configured to transmit a wide beam acoustic locator signal.

24. The system of claim 22, wherein the transducer array is configured to sequentially transmit focused acoustic locator signals until the receiver-converter generates a location signal or a preset time limit has been reached.

25. The system of claim 22, wherein the location signal is an electrical output, wherein the electrical output is detected by a sensing circuit which uses an electrode assembly adapted to be in electrical communication with tissue.

26. The system of claim 22, wherein the receiver-converter is adapted to generate an acoustic output and the location signal is an acoustic transmission.

27. The system of claim 24, wherein the focused acoustic energy is transmitted by the controller-transmitter, converted to electrical energy by the receiver-converter;

and the receiver-converter is adapted to store the electrical energy.

28. The system of claim 24, wherein the focused acoustic energy is transmitted by the controller-transmitter;

converted to electrical energy by the receiver-converter; and

the receiver-converter is adapted to use the electrical energy to operate one or more of control circuitry, diagnostic sensing circuitry, and communication circuitry.

29. The system of claim 28, wherein the receiver-converter is further adapted to transmit sensed diagnostic data.

30. A system for stimulating tissue comprising:

an implantable acoustic controller-transmitter comprising an acoustic transducer array adapted to transmit acoustic energy into tissue; and

an implantable acoustic receiver-stimulator which receives acoustic energy and converts the acoustic energy to electrical energy and which has a first electrode assembly connected to the receiver-stimulator and adapted to be in electrical communication with the tissue, wherein the receiver-stimulator periodically transmits a location signal, and wherein the controller-transmitter detects the location signal.

31. The system of claim 30, wherein the location signal is an electrical output, wherein the electrical output is detected by a sensing circuit which uses a second electrode assembly adapted to be in electrical communication with tissue.

32. The system of claim 30, wherein the receiver-stimulator is adapted to generate an acoustic output and the location signal is an acoustic transmission.

33. The system of claim 30, wherein the transducer array is adjusted using electrical drive signals to transmit focused acoustic energy towards the receiver-stimulator based on the characteristics of the location signal that is detected by the controller-transmitter.

34. The system of claim 33, wherein the focused energy is at sufficient levels to stimulate cardiac tissue.

35. The system of claim 33, wherein the electrical drive signals to the transducer array is adjusted based on one or more parameters including frequency, duration, amplitude, phase, and time of flight of the location signal to transmit focused acoustic energy towards the receiver-stimulator.

36. A method for optimizing acoustic energy transmission in tissue between an implantable controller-transmitter and one or more implantable receiver-stimulators comprising:

transmitting an acoustic locator signal from the controller-transmitter towards the receiver-stimulator, wherein the controller-transmitter comprises an adjustable transducer array; and

generating a location signal from the receiver-stimulator in response to receiving the locator signal.

37. The method of claim 36 further comprising detecting the location signal using the controller-transmitter;

and adjusting the transducer array to transmit focused acoustic energy towards the receiver-stimulator.

38. The method of claim 36 comprising adjusting the transducer array sequentially to transmit focused locator signals to regions of the tissue until the receiver-stimulator location signal is detected by the controller-transmitter or a pre-set time limit has been reached;

and adjusting the transducer array to transmit focused acoustic energy to the region associated with the detected location signal.

39. The method of claim 36, further comprising adjusting the transducer array to transmit a wide beam acoustic locator signal.

40. The method of claim 36, wherein the location signal is an electrical output and further detecting the electrical output using a sensing circuit.

41. The method of claim 36, wherein the location signal is an acoustic output.

42. The method of claim 36, further comprising:

detecting the location signal using the controller-transmitter;

adjusting the transducer array based on the location signal; and

transmitting focused acoustic energy towards the receiver-stimulator.

43. The method of claim 38, wherein the receiver-stimulator is adapted with a first electrode assembly and the electrode assembly is in electrical communication with the tissue, further comprising:

converting the acoustic energy using the receiver-stimulator, and

applying the converted energy to the first electrode assembly.

44. The method of claim 43, further comprising stimulating the tissue.

45. The method of claim 44, where the tissue is cardiac tissue.

46. The method of claim 37, further comprising:

characterizing the location signal using one or more characteristics of the location signal including frequency, duration, amplitude, phase, and time of flight;

determining a region of the tissue containing the receiver-stimulator based on the location signal;

adjusting the transducer array toward the receiver-stimulator based on the location signal; and

transmitting operationally efficient acoustic energy towards the receiver-stimulator.