ALGORITHM ADAPTATION TO AN EXTERNAL IMPACT ON THE DATA

• US 20140236029A1
• Filed: 02/11/2014
• Published: 08/21/2014
• Est. Priority Date: 02/18/2013
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Averina, Viktoria A., Thakur, Pramodsingh Hirasingh, Zhang, Yi, An, Qi
• Granted Patent: US 9,643,012 B2
• Time in Patent Office: Days
• US Class Current: 600/508
• CPC Class Codes: A61B 2560/0276 Determining malfunction
• CPC Class Codes: A61B 5/02055 Simultaneously evaluating both cardiovascular condition and temperature
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/4839 combined with drug delivery
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61B 5/7221 Determining signal validity, reliability or quality A61B5/7207 and A61B5/7217 take precedence
• CPC Class Codes: A61B 5/7278 Artificial waveform generation or derivation, e.g. synthesising signals from measured signals A61B5/327 takes precedence
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy

Abstract

Devices and methods for detecting a physiological target event such as events indicative of HF decompensation status are described. An ambulatory medical device is configured to determine the presence and timing of a confounding event, segment a sensed physiological signal into at least two data segments, adjust the physiological signal by removing or lessening the impact of the confounding event on the physiological signal. The adjusted data can be presented to the user, and the ambulatory medical device can detect the target events using the adjusted physiologic signal. In some embodiments, the ambulatory medical device can be configured to detect an event indicative of HF decompensation using a physiological signal and the information of the detected confounding event.

Claims

1. An ambulatory medical device, comprising:

a signal receiver circuit, configured to receive a physiologic signal, for detecting a physiologic target event or condition of a patient;

a confounding event detector circuit, including a confounding event-bearing (CEB) signal receiver circuit configured to receive at least one CEB signal, the confounding event detector configured to determine presence of a confounding event, different from the target event or condition, from the at least one CEB signal;

a signal processing circuit, configured to segment the physiologic signal into at least first and second segments, and adjust at least one of the first or second segments, wherein adjusting at least one of the first or second segments is capable of being independent of adjusting the other of the first and second segments; and

a target event or condition detector circuit, configured to detect the target event or condition from the at least one of the first or second adjusted segments of the physiologic signal.

2. The device of claim 1, wherein the signal receiver circuit is configured to be coupled to at least one of a signal memory or a signal sensing circuit, and wherein the signal sensing circuit, coupled to electrodes associated with the ambulatory medical device, is configured to sense the physiologic signal.

3. The device of claim 1, wherein the confounding event detector circuit is configured to detect, from the at least one CEB signal, an event indicative of at least one of a change of integrity of the device, a change of configuration of the device, a change of interaction between the device and the patient, a change of patient environment, a change of the patient condition, a replacement of the device, and a medical event.

4. The device of claim 1, wherein the CEB signal receiver circuit is configured to be coupled to electrodes associated with the patient and receive at least one CEB physiologic signal, and wherein the confounding event detector is configured to determine the presence of the confounding event using whether the at least one CEB physiologic signal meets at least one physiologically relevant criterion.

5. The device of claim 1, wherein the CEB signal receiver circuit is configured to receive at least one clinical report, and wherein the confounding event detector is configured to determine the presence of the confounding event using whether the at least one clinical report indicates the confounding event.

6. The device of claim 1, wherein the CEB signal receiver circuit is configured to receive two or more CEB signals selected from a plurality of CEB physiologic signals and a plurality of clinical reports, and wherein the confounding event detector circuit is configured to perform detection of the confounding event using the two or more CEB signals, and determine the presence of the confounding event using a comparison of the detections from the two or more CEB signals.

7. The device of claim 1, wherein the signal processing circuit is configured to:

segment the physiologic signal into at least the first and second segments using a characteristic parameter of the detected confounding event, the characteristic parameter including a start time, a stop time, a duration, and a type of the detected confounding event; and

adjust the at least one of the first and second segments using a comparison between a first metric determined from the first segment and a second metric determined from the second segment.

8. The device of claim 1, wherein the signal processing circuit is configured to determine a mode of adjustment using at least one of the type of the detected confounding event, a type of the physiologic signal, and a sensing configuration of the physiological signal, and wherein the mode of adjustment includes a transient adjustment and a permanent adjustment.

9. A method, comprising:

receiving a physiologic signal, sensed from a patient, for detecting a physiologic target event or condition of the patient;

detecting a confounding event, different from the target event or condition, from at least one confounding event-bearing (CEB) signal;

using the detected confounding event, segmenting the physiologic signal into at least first and second segments;

adjusting at least one of the first or second segments, wherein adjusting at least one of the first or second segments is capable of being independent of adjusting the other of the first and second segments; and

applying a target event or condition detection algorithm to the adjusted at least one of the first or second segments of the physiologic signal, to detect the target event or condition of the patient.

10. The method of claim 9, wherein the confounding event includes an event indicative of at least one of a change of integrity of an ambulatory medical device associated with the patient, a change of configuration of the ambulatory medical device, a change of interaction between the ambulatory medical device and the patient, a change of patient environment, a change of the patient condition, a replacement of the ambulatory medical device, and a medical event.

11. The method of claim 9, wherein detecting the confounding event includes:

receiving at least one CEB physiologic signal from electrodes associated with the patient; and

determining presence of the confounding event using whether the at least one CEB physiologic signal meets at least one physiologically relevant criterion, including a change in intensity, a rate of change in intensity, and a duration of sustained shift in intensity of the CEB physiologic signal.

12. The method of claim 9, wherein detecting the confounding event includes:

computing a similarity measure between the at least one CEB signal and at least one confounding event template signal; and

determining presence of the confounding event using whether the similarity measure meets at least one specified criterion.

13. The method of claim 9, wherein detecting the confounding event includes:

receiving at least one clinical report; and

determining presence of the confounding event using whether the at least one clinical report indicates the presence of the confounding event.

14. The method of claim 9, wherein detecting the confounding event includes:

performing detection of the confounding event using each of two or more CEB signals, the two or more CEB signals selected from a plurality of CEB physiologic signals and a plurality of clinical reports; and

determining presence of the confounding event using a comparison of the detections from the two or more CEB signals.

15. The method of claim 9, wherein detecting the confounding event includes:

generating a composite signal using the two or more CEB signals; and

determining presence of the confounding event using whether the composite signal meets at least one physiologically relevant criterion, including a change in intensity, a rate of change in intensity, and a duration of sustained shift in intensity of the composite signal.

16. The method of claim 9, wherein segmenting the physiologic signal includes segmenting the physiologic signal into at least the first and second segments using a characteristic parameter of the detected confounding event, the characteristic parameter including a start time, a stop time, a duration, and a type of the detected confounding event.

17. The method of claim 16, wherein the first segment is taken from the physiologic signal before the start time of the confounding event, and the second segment is taken from the sensed physiologic signal after the stop time of the detected confounding event.

18. The method of claim 9, wherein adjusting the physiologic signal includes adjusting the at least one of the first and second segments using a comparison between a first metric determined from the first segment and a second metric determined from the second segment.

19. The method of claim 9, wherein adjusting the physiologic signal includes a mode of adjustment using at least one of the type of the detected confounding event, a type of the physiologic signal, and a sensing configuration of the physiological signal, and wherein the mode of adjustment includes a transient adjustment and a permanent adjustment.

20. A method, comprising:

receiving an impedance signal, sensed from a patient, for detecting a target event indicative of HF decompensation status of the patient;

detecting a confounding event, different from the target event, from at least one confounding event-bearing (CEB) physiologic signal, wherein detecting the confounding event includes determining presence of the confounding event using whether a rate of change of the intensity of the CEB physiologic signal is within a specified range of physiologically relevant rate of change of the CEB physiologic signal;

segmenting the impedance signal into at least first and second segments, the first segment taken before the start time of the detected confounding event, and the second segment taken after the stop time of the detected confounding event;

adjusting the impedance signal by subtracting from at least one of the first and second segments a difference between an average intensity of the first segment and an average intensity of the second segment; and

applying a HF decompensation detection algorithm to the adjusted impedance signal to detect the target event indicative of HF decompensation status.