Method and apparatus for identifying heartbeat

• US 6,575,915 B2
• Filed: 10/04/2001
• Issued: 06/10/2003
• Est. Priority Date: 06/20/1996
• Status: Expired due to Term

• Current Assignee: Polar Electro Oy
• Original Assignee: Polar Electro Oy
• Inventors: Miettinen, Jari, Ruha, Antti, Nissilä, Seppo, Sorvoja, Hannu
• Primary Examiner(s): Nasser, Robert L.
• Application Number:
  US09/970,497
• Publication Number:
  US 20020120202A1
• Time in Patent Office: 614 Days
• Field of Search: 600/485, 600/453-6, 600/500-3
• US Class Current: 600/500
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/681 Wristwatch-type devices
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts

Abstract

The invention relates to a method and an apparatus for identifying a heartbeat. In the method, an arterial pressure signal is measured in the form of multichannel measurement, and the required signal-processing operations, such as filtration, are carried out if necessary. The method also comprises carrying out signal detection and decision-making concerning the acceptance as a heartbeat signal. According to the invention, the signal detection includes multichannel channel-specific detection for the purpose of identifying signal components of different channels, and the obtained channel-specific detected channel signals are used as input data during the decision-making stage.

Claims

1. A method for identifying a heartbeat comprising the steps of:

measuring an arterial pressure signal in the form of multi-channel measurement; and

performing signal detection and decision-making concerning the identification of a heartbeat signal;

wherein said signal detection includes multi-channel channel-specific detection for the purpose of identifying signal components of different channels, and said obtained channel-specific detected channel signals are used as input data in said decision-making, whereby said heartbeat signal includes data from at least two channels.

2. A method according to claim 1, further including the step of weighting said channel signals for said decision-making based on the heartbeat signal previously occurring in said channels.

3. A method according to claim 2, further including the step of weighting utilizing weighting coefficients that can be updated.

4. A method according to claim 3, further including the step of updating said weighting coefficients on the basis of empirical rules.

5. A method according to claim 4, further including the step of weighting adjacent channels having similar signals more than other channels during said decision-making.

6. A method according to claim 4, further including the step of weighting non-adjacent channels having similar signals less than other channels during said decision making.

7. A method according to claim 2, further including the step of weighting after said channel-specific detection and before said decision-making.

8. A method according to claim 1 further including the step of performing signal detection and decision-making concerning the identification of a signal as a non-heartbeat signal.

9. A method according to claim 1 further including the step of forming at least one channel signal with no heartbeat signal.

10. A method according to claim 1 further including the step of filtering said signals both specifically for each channel and with respect to the other channels.

11. A method according to claim 1 further including the step of reducing the interference of each channel by subjecting the signals of all of said channels to band-pass filtration and subtracting a common-mode interference signal from said signal of each channel.

12. A method according to claim 1, further including the step of obtaining said signals from the artery at the wrist by using a wrist strap including a sensor.

13. An apparatus for identifying a heartbeat comprising:

a multichannel sensor, the multichannel sensor measuring an arterial pressure signal in the form of a multichannel measurement;

detection means, the detection means detecting a signal; and

decision-making means, the decision making means performing decision-making concerning the identification of the signal as a heartbeat signal, said detection means performing multichannel channel-specific detection for the purpose of identifying signal components of different channels, channel-specific detected channel signals being used as input data to said decision-making means, a decision being made by said decision-making means on the basis of cross-correlation of signals occurring in two or more adjacent channels.

14. An apparatus according to claim 13 further comprising weighting means, the weighting means weighting said signals of one or more channels differently from the other channels.

15. An apparatus according to claim 14 further comprising a rule means, the rule means controlling said weighting means.

16. An apparatus according to claim 13 wherein said multichannel sensor is positioned such that at least one sensing element is situated over the artery and at least one other sensing element is not situated over the artery.

17. An apparatus according to claim 13 further including signal processing means, the signal processing means processing a signal obtained from said multichannel sensor, said signal processing means being coupled to said detection means.

18. An apparatus for identifying a heartbeat comprising:

a multichannel sensor, the multichannel sensor measuring an arterial pressure signal in the form of a multichannel measurement;

detection means, the detection means detecting a signal; and

decision-making means, the decision making means performing decision-making concerning the identification of the signal as a heartbeat signal, said detection means performing multichannel channel-specific detection for the purpose of identifying signal components of different channels, channel-specific detected channel signals being used as input data to said decision-making means, a decision being made by said decision-making means on the basis of common-mode signals occurring simultaneously in two or more adjacent channels.

19. An apparatus according to claim 18 further comprising weighting means, the weighting means weighting said signals of one or more channels differently from the other channels.

20. An apparatus according to claim 19 further comprising a rule means, the rule means controlling said weighting means.

21. An apparatus according to claim 18 wherein said multichannel sensor is positioned such that at least one sensing element is situated over the artery and at least one other sensing element is not situated over the artery.

22. An apparatus according to claim 18 further including signal processing means, the signal processing means processing a signal obtained from said multichannel sensor, said signal processing means being coupled to said detection means.

23. An apparatus for identifying a heartbeat comprising:

a multichannel sensor, the multichannel sensor measuring an arterial pressure signal in the form of a multichannel measurement;

detection means, the detection means detecting a signal; and

decision-making means, the decision making means performing decision-making concerning the identification of the signal as a heartbeat signal, said detection means performing multichannel channel-specific detection for the purpose of identifying signal components of different channels, channel-specific detected channel signals being used as input data to said decision-making means, a decision being made by said decision-making means on the basis of a signal occurring regularly in one channel when said heartbeat signal cannot be identified on the basis of monitoring two or more adjacent channels.

24. An apparatus according to claim 23 further comprising weighting means, the weighting means weighting said signals of one or more channels differently from the other channels.

25. An apparatus according to claim 24 further comprising a rule means, the rule means controlling said weighting means.

26. An apparatus according to claim 23 wherein said multichannel sensor is positioned such that at least one sensing element is situated over the artery and at least one other sensing element is not situated over the artery.

27. An apparatus according to claim 23 further including signal processing means, the signal processing means processing a signal obtained from said multichannel sensor, said signal processing means being coupled to said detection means.

30. An apparatus according to claim 27 further comprising a rule means, the rule means controlling said weighting means.

28. An apparatus for identifying a heartbeat comprising:

a multichannel sensor, the multichannel sensor measuring an arterial pressure signal in the form of a multichannel measurement;

detection means, the detection means detecting a signal; and

decision-making means, the decision making means performing decision-making concerning the identification of the signal as a heartbeat signal, said detection means performing multichannel channel-specific detection for the purpose of identifying signal components of different channels, said detection means identifying a heartbeat pulse component of said arterial pressure signal as part of said signal components of said different channels, channel-specific detected channel signals being used as input data to said decision-making means.

29. An apparatus according to claim 28 further comprising weighting means, the weighting means weighting said signals of one or more channels differently from the other channels.

31. An apparatus according to claim 28 wherein said multichannel sensor is positioned such that at least one sensing element is situated over the artery and at least one other sensing element is not situated over the artery.

32. An apparatus according to claim 28 further including signal processing means, the signal processing means processing a signal obtained from said multichannel sensor, said signal processing means being coupled to said detection means.