Apparatus and method for quantification of the desynchronization between the clocks of two HBC active implants

• US 9,302,115 B2
• Filed: 04/21/2014
• Issued: 04/05/2016
• Est. Priority Date: 02/09/2011
• Status: Active Grant

• Current Assignee: Sorin CRM USA (MicroPort Scientific Corp.)
• Original Assignee: Sorin CRM USA (MicroPort Scientific Corp.)
• Inventors: Molin, Renzo Dal, Ghildiyal, Ashutosh
• Primary Examiner(s): Ahn, Sam K
• Assistant Examiner(s): Murillo Garcia, Fabricio R
• Application Number:
  US14/257,195
• Publication Number:
  US 20140228913A1
• Time in Patent Office: 715 Days
• US Class Current: 1/1
• CPC Class Codes: A61N 1/37205 Microstimulators, e.g. implantable through a cannula
• CPC Class Codes: A61N 1/37288 Communication to several implantable medical devices within one patient
• CPC Class Codes: A61N 1/39622 Pacing therapy
• CPC Class Codes: G06F 1/06 Clock generators producing several clock signals G06F1/08 - G06F1/14 take precedence
• CPC Class Codes: G06F 1/12 Synchronisation of different clock signals provided by a plurality of clock generators
• CPC Class Codes: H04B 17/00 Monitoring; Testing of line transmission systems H04B3/46; arrangements for monitoring or testing transmission systems employing electromagnetic waves other than radio waves H04B10/07
• CPC Class Codes: H04B 3/46 Monitoring; Testing
• CPC Class Codes: H04J 3/06 Synchronising arrangements for television systems H04N5/04; bit-synchronisation H04L7/00
• CPC Class Codes: H04Q 1/20 Testing circuits or apparatus; Circuits or apparatus for detecting, indicating, or signalling faults or troubles

Abstract

A method of determining desynchronization between a first implantable medical device and a second implantable medical device. The method includes receiving a synchronization query from the first device at the second device, that is transmitted in response to the first device detecting a predetermined transition of a first clock of the first device, the first clock having a first pulse rate. The method further includes determining a number of pulses of a second clock of the second device occurring between reception of the synchronization query and a predetermined transition of a third clock of the second device, the third clock having the first pulse rate. The second clock has a second pulse rate higher than the first pulse rate. The method further includes determining the desynchronization between the first device and the second device based on the determined number of pulses of the second clock.

Claims

1. A method of determining a desynchronization between a first implantable medical device (IMD) and a second IMD, the method comprising:

receiving, by a receiver of the second IMD, a synchronization query (SYNC) from the first IMD, the SYNC being transmitted in response to the first IMD detecting a predetermined transition of a first clock of the first IMD, the first clock having a first pulse rate;

activating, only upon reception of the SYNC, a second clock of the second IMD, the activating of the second clock being triggered by a control circuit of the second IMD after detection of the SYNC by the receiver of the second IMD;

determining, by a counting circuit of the second IMD, a number of pulses of the second clock occurring between reception of the SYNC and a predetermined transition of a third clock of the second IMD, the third clock having the first pulse rate, and the second clock having a second pulse rate higher than the first pulse rate, thereby generating a determined number of pulses of the second clock based on the synchronization query and the transition of the third clock;

activating, after the transmission of the SYNC from the first IMD to the second IMD, a fourth clock of the first IMD;

sending, to the first IMD, the determined number of pulses of the second clock and turning off the second clock;

receiving, by a receiver of the first IMD which is initiated only during a reception window triggered by a clock signal of the fourth clock, the determined number of pulses of the second clock; and

determining, upon reception of the determined number of pulse of the second clock, the desynchronization between the first IMD and the second IMD based on the determined number of pulses of the second clock, then deactivating the fourth clock.

2. The method of claim 1, further comprising:

determining a number of pulses of the fourth clock of the first IMD occurring between transmission of the SYNC and reception of a response signal to the SYNC, the fourth clock having the second pulse rate; and

determining the desynchronization between the first IMD and the second IMD based on both the determined number of pulses of the second clock and the determined number of pulses of the fourth clock.

3. The method of claim 2, wherein determining the desynchronization between the first IMD and the second IMD comprises applying a relation of the form:

OFFSET=T_clk−

[(D₁+D₂)/2],

wherein OFFSET is the value of a temporal offset corresponding to the desynchronization, T_clk is the period of the pulse signals of the first and the third clock, D₁ is the duration corresponding to the result from determining the number of pulses of the second clock, and D₂ is the duration corresponding to the result from determining the number of pulses of the fourth clock.

4. The method of claim 1, wherein the first pulse rate is selected from the range of 15 and 50 kHz.

5. The method of claim 1, wherein the second pulse rate is at least 10 times faster than the first pulse rate.

6. The method of claim 1, wherein determining the desynchronization between the first IMD and the second IMD comprises applying a relation of the form:

OFFSET=T_clk−

D,

wherein OFFSET is the value of a temporal offset corresponding to the desynchronization, T_clk is the period of the pulse signals of the first clock, and D is the duration corresponding to the result from determining the number of pulses of the second clock.

7. An active implantable medical device (IMD), comprising:

an apparatus for providing information to determine a desynchronization between the active IMD and a second medical device, the apparatus comprising;

a transmitter/receiver of wireless communications;

a first clock having a first pulse rate; and

a second clock having a second pulse rate higher than the first pulse rate;

the apparatus configured to;

receive, by the receiver of the active IMD, a synchronization query (SYNC) from the second medical device, the synchronization query being transmitted in response to a predetermined transition of a third clock of the second medical device, the third clock having the first pulse rate;

activate, only upon reception of the SYNC, the second clock of the IMD, the activating of the second clock being triggered by a control circuit of the IMD after detection of the SYNC by the receiver of the IMD,

determine, by a counting circuit of the IMD, a number of pulses of the second clock of the apparatus occurring between reception of the SYNC and a predetermined transition of the first clock of the apparatus, thereby generating the determined number of pulses of the second clock based on the synchronization query and the transition of the first clock; and

transmit a response signal comprising the determined number of pulses of the second clock to the second medical device and turn off the second clock;

wherein the response signal is configured to allow the second medical device to determine, upon reception of the number of pulses of the second clock, the desynchronization between the active IMD and the second medical device based on the determined number of pulses of the second clock;

wherein a fourth clock of the second medical device is configured to be activated after the transmission of the SYNC from the second medical device and deactivated after determining the desynchronization between the IMD and the second medical device; and

wherein a receiver of the second medical device is initiated only during a reception window triggered by a clock signal of the fourth clock and is configured to receive the response signal.

8. The active IMD of claim 7, wherein the first pulse rate is selected from the range of 15 and 50 kHz.

9. The active IMD of claim 7, wherein the second pulse rate is at least 10 times faster than the first pulse rate.

10. The active IMD of claim 7, wherein determining the desynchronization between the active IMD and the second medical device comprises applying a relation of the form:

OFFSET=T_clk−

D,

wherein OFFSET is the value of a temporal offset corresponding to the desynchronization, T_clk is the period of the pulse signals of the first clock, and D is the duration corresponding to the result from determining the number of pulses of the second clock.

11. The active IMD of claim 7, wherein the active IMD is an autonomous leadless capsule.

12. A non-transitory computer-readable storage medium having instructions stored thereon that, when executed by a processor of an implantable medical device (IMD), cause the implantable medical device to perform operations comprising:

selectively activating, by a control circuit of the IMD, a first clock of the implantable medical device upon reception, at a receiver of the IMD, of a synchronization query (SYNC) from a second medical device, the first clock having a first pulse rate;

determining, by a counting circuit of the IMD, a number of pulses of the first clock of the IMD occurring between reception of the synchronization query and a predetermined transition of a second clock of the IMD, wherein the first pulse rate is higher than a second pulse rate of the second clock, thereby generating the determined number of pulses of the first clock based on the synchronization query and the transition of the second clock;

sending, to the second medical device, the determined number of pulses of the first clock;

wherein the SYNC is transmitted in response to a predetermined transition of a third clock of the second medical device, the third clock having the second pulse rate;

wherein a fourth clock of the second medical device is activated after transmission of the SYNC;

wherein the operations further comprise;

deactivating the first clock of the IMD after detection of the predetermined transition of the second clock; and

determining the desynchronization between the IMD and the second medical device based on the determined number of pulses of the first clock; and

wherein the determined number of pulses of the first clock is received by a receiver of the second medical device which is initiated only during a reception window triggered by a clock signal of the fourth clock.

13. The non-transitory computer-readable medium of claim 12, wherein determining the desynchronization between the IMD and the second medical device comprises applying a relation of the form:

OFFSET=T_clk−

D,

wherein OFFSET is the value of a temporal offset corresponding to the desynchronization, T_clk is the period of the pulse signals of the second clock, and D is the duration corresponding to the result from determining the number of pulses of the first clock.

14. A system for determining a desynchronization between a first implantable medical device and a second implantable medical device, comprising:

a first implantable medical device (IMD) comprising;

a first transmitter/receiver of wireless communications;

a first clock having a first pulse rate; and

a second clock having a second pulse rate higher than the first pulse rate; and

a second implantable medical device (IMD) comprising;

a second transmitter/receiver of wireless communications;

a third clock having the first pulse rate; and

a fourth clock having the second pulse rate;

wherein the system is configured to;

detect a predetermined transition of the first clock of the first IMD and in response, transmit a synchronization query (SYNC) to the second IMD;

receive, by a receiver of the second IMD, the SYNC at the second IMD;

activate, only upon reception of the SYNC, the fourth clock of the second IMD, the activating of the fourth clock being triggered by a control circuit of the second IMD after detection of the SYNC by the receiver of the second IMD;

activating, after the transmission of the SYNC from the first IMD to the second IMD, the second clock of the first IMD;

determine, by a counting circuit of the system, a number of pulses of the fourth clock of the second IMD occurring between reception of the SYNC and a predetermined transition of the third clock of the second IMD, thereby generating the determined number of pulses of the fourth clock based on the SYNC and the transition of the third clock;

transmit a response signal comprising the determined number of pulses of the fourth clock from the second IMD to the first IMD and then deactivate the fourth clock;

receiving, by a receiver of the first IMD which is initiated only during a reception window triggered by a clock signal of the second clock, the response signal comprising the determined number of pulses of the fourth clock; and

determine, by the counting circuit or a second counting circuit, a number of pulses of the second clock of the first IMD occurring between transmission of the SYNC and reception of the response signal, thereby generating a determined number of pulses of the second clock based on the SYNC and the response signal, and then deactivate the second clock; and

determine the desynchronization between the first IMD and the second IMD based on both the determined number of pulses of the second clock and the determined number of pulses of the fourth clock.

15. The system of claim 14, wherein at least one of the first IMD and the second IMD is an autonomous leadless capsule.

16. The system of claim 14, wherein the first pulse rate is selected from the range of 15 and 50 kHz.

17. The system of claim 14, wherein the second pulse rate is at least 10 times faster than the first pulse rate.

18. The system of claim 14, wherein determining the desynchronization between the first IMD and the second IMD comprises applying a relation of the form:

OFFSET=T_clk−

[(D₁+D₂)/2],

wherein OFFSET is the value of a temporal offset corresponding to the desynchronization, T_clk is the period of the pulse signals of the first and the third clock, D₁ is the duration corresponding to the result from determining the number of pulses of the second clock, and D₂ is the duration corresponding to the result from determining the number of pulses of the fourth clock.