On-demand retransmission of data with an implantable medical device

• US 20050283209A1
• Filed: 06/17/2004
• Published: 12/22/2005
• Est. Priority Date: 06/17/2004
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Rawat, Prashant, Katoozi, Mehdi, Vanderlinde, Scott, Cowan, Ken, Rutzer, Mark, Bocek, Tom
• Granted Patent: US 7,457,669 B2
• Time in Patent Office: Days
• US Class Current: 607/60
• CPC Class Codes: A61N 1/37254 Pacemaker or defibrillator security, e.g. to prevent or inhibit programming alterations by hackers or unauthorised individuals
• CPC Class Codes: Y10S 128/903 Radio telemetry

Abstract

This document discloses, among other things, a telemetry system for requesting and receiving redundant data. A synchronization frame transmitted by an external device includes an echo code. The implantable device responds to the synchronization frame by sending real time data and echo data selected as a function of the echo code.

Claims

1. An implantable device comprising:

a data source configured to provide a series of data units;

a memory configured to store a plurality of the data units selected from the series of data units;

a processor configured to selectively access at least one data unit stored in the memory; and

a transceiver coupled to the processor and configured to receive a sequence of synchronization signals, wherein at least one synchronization signal includes an echo code, and configured to transmit the at least one data unit selected from the memory wherein the at least one data unit includes a number of data units selected as a function of the echo code.

2. The device of claim 1, further including error detection circuitry coupled to the memory wherein the error detection circuitry is configured to provide data to enable error detection.

3. The device of claim 2, wherein the error detection circuitry generates a cyclic redundancy check code.

4. The device of claim 1, wherein the data source includes a monitor circuit.

5. The device of claim 1, wherein the data source includes a pulse generator.

6. The device of claim 1, wherein the data source provides intracardiac electrogram data.

7. The device of claim 1, wherein the transceiver includes a far field radio frequency transmitter.

8. The device of claim 1, wherein the memory includes storage for at least three data units.

9. A device comprising:

a transceiver configured to transmit a sequence of synchronization signals, at least one synchronization signal including an echo code and configured to receive a sequence of replies from an implantable device, wherein each reply corresponds to each synchronization signal in one to one relation;

a processor coupled to the transceiver and configured to detect an error in a reply; and

a memory coupled to the processor and configured to store a sequence of data units corresponding to the sequence of replies wherein each data unit is generated by the processor as a function of at least one reply of the sequence of replies wherein the at least one reply includes a number of replies selected as a function of the echo code.

10. The device of claim 9, further including at least one of any combination of a printer, a display and a repeater coupled to the processor.

11. The device of claim 9, wherein the transceiver includes a far field radio frequency transmitter.

12. The device of claim 9, wherein the echo code is selected as a function of an error rate.

13. The device of claim 9, further including:

an input interface coupled to the processor to receive input data for controlling the implantable device; and

an output interface coupled to the processor to provide output information based on the sequence of data units.

14. The device of claim 13, wherein at least one of any combination of the input interface and the output interface is coupled to a network interface adapted to communicate with a communication network.

15. The device of claim 13, wherein the output interface is coupled to a display.

16. The device of claim 9, wherein the processor includes circuitry to compare a cyclic redundancy check code received with the reply and a calculated cyclic redundancy check code.

17. A method comprising:

receiving a sequence of synchronization signals, each synchronization signal having a corresponding echo code;

transmitting a new data unit in response to each synchronization signal; and

transmitting a number of duplicate data units with each new data unit, wherein the number is selected using a value of the corresponding echo code received with the synchronization signal.

18. The method of claim 17, wherein each new data unit is generated based on at least one of an electrogram and an event marker.

19. The method of claim 17, further including buffering the number of duplicate data units in a memory.

20. The method of claim 17, wherein transmitting includes transmitting a far field radio frequency signal.

21. The method of claim 17, further including appending the number of duplicate data units to the new data unit.

22. The method of claim 17, further including transmitting an error detection code with each new data unit.

23. The method of claim 22, wherein transmitting the error detection code includes calculating and transmitting a cyclic redundancy code.

24. The method of claim 17, further including appending the number of duplicate data units to the new data unit and further including calculating and transmitting a cyclic redundancy code with each new data unit.

25. A method comprising:

transmitting a series of synchronization signals wherein each synchronization signal includes an echo code; and

for each synchronization signal, receiving a new data unit and receiving a number of duplicate data units from an implantable device wherein the number is selected using a value of the echo code.

26. The method of claim 25, wherein transmitting includes transmitting a far field radio frequency signal.

27. The method of claim 25, further including rendering an image on a display using a received new data unit and any received duplicate data units.

28. The method of claim 25, wherein each duplicate data unit corresponds to a new data unit.

29. The method of claim 25, wherein the echo code includes a two bit value.

30. The method of claim 25, wherein the number is selected from the group of 0, 1 and 2.

31. The method of claim 25, wherein receiving the new data unit and receiving the number of duplicate data units includes receiving the new data unit before receiving the number of duplicate data units.

32. The method of claim 25, further including generating an error code based on the received new data unit and the number of duplicate data units.

33. The method of claim 32, wherein the echo code is selected as a function of the error code.

34. The method of claim 33, wherein the echo code corresponds to a request for greater than zero duplicate data units.

35. The method of claim 25, wherein the echo code is remotely selectable.

36. A system comprising:

a non-implantable transceiver configured to provide a synchronization pulse including an echo code;

an implantable receiver configured to receive the synchronization pulse; and

an implantable transmitter coupled to the receiver and configured to transmit a data frame in response to the synchronization pulse wherein the data frame includes a new data unit and a number of duplicate data units and wherein the number of duplicate data units is specified by a value of the echo code in response to a determination that a previous data frame includes an error.

37. The system of claim 36, further including a memory coupled to the transmitter wherein the memory provides storage for the new data unit and at least one duplicate data unit.

38. The system of claim 36, further including an error detection code calculator coupled to the implantable transmitter wherein the data frame includes an error code generated by the error detection code calculator as a function of the new data unit and the number of duplicate data units.

39. The system of claim 38, further including:

comparator means coupled to the non-implantable transceiver; and

code generator means coupled to the non-implantable transceiver; and

wherein the code generator means is configured to generate a calculated code as a function of the new data unit and the number of duplicate data units; and

wherein the comparator means is configured to generate an output based on a comparison of the error code and the calculated code.

40. The system of claim 39, wherein the echo code is generated as a function of the output.

41. The system of claim 39, wherein the echo code is set to a value corresponding to a request for at least one duplicate data unit if the output indicates that the error code differs from the calculated code.

42. An implantable device comprising:

a storage device configured to store time ordered data from a data source;

a processor coupled to the storage device; and

a transceiver coupled to the processor and configured to receive an inbound signal and configured to transmit outbound data if the inbound signal includes a synchronization signal, wherein the processor is configured to select the outbound data from the time ordered data as a function of an echo code of the synchronization signal.

43. The device of claim 42, further including a clock coupled to the processor and wherein the processor is configured to estimate, as a function of a clock signal from the clock, a time of occurrence of a synchronization signal in the absence of a received synchronization signal.

44. The device of claim 42, further including an error detector coupled to the transceiver and configured to identify an error in the inbound signal.

45. The device of claim 42, wherein the data source includes at least one of a monitor circuit and a pulse generator.

46. A method comprising:

monitoring for an inbound signal at an implantable device;

if the inbound signal includes a synchronization signal, then transmitting, from the implantable device, a reply signal having a current data unit and a number of duplicate data units, wherein the number of duplicate data units is selected as a function of an echo code of the synchronization signal; and

if the inbound signal does not include a synchronization signal, then estimating a time of occurrence of the synchronization signal and storing the current data unit in a queue.

47. The method of claim 46, further including executing a comparison algorithm to determine if the inbound signal includes a synchronization signal.

48. The method of claim 46, further including transmitting the synchronization signal from an external device.

49. The method of claim 48, wherein transmitting the synchronization signal includes encoding the synchronization signal with the echo code wherein the echo code is selected as a function of a reply signal received by the external device.

50. The method of claim 46, wherein estimating the time of occurrence of the synchronization signal includes monitoring for expiration of a timer.

51. The method of claim 50, wherein the estimated time of occurrence is associated with the stored current data unit.