System and method for characterizing cardiac arrhythmia

Patent metadata

Field	Value
Publication number	US-10398381-B1
Application number	US-201615356383-A
Country	US
Kind code	B1
Filing date	Nov 18, 2016
Priority date	Nov 19, 2015
Publication date	Sep 3, 2019
Grant date	Sep 3, 2019

Abstract

In an embodiment, a data processing method comprises obtaining one or more photoplethysmography (PPG) signals from one or more PPG sensors of a monitoring apparatus, the PPG signals being generated based upon optically detecting pulsed variations in blood flow; obtaining a motion sensor signal from a motion sensor in the monitoring apparatus; identifying, based upon the motion sensor signal, one or more periods of motion (e.g., low motion) of the monitoring apparatus; and selectively obtaining and storing segments of the PPG signals based on a temporal relationship between the segments of the PPG signals and the identified periods of motion.

First claim

What is claimed is:

1. A method comprising:
obtaining one or more photoplethysmography (PPG) signals from one or more PPG sensors of a monitoring apparatus, the one or more PPG signals being generated based upon optically detecting pulsed variations in blood flow;
obtaining a motion sensor signal from a motion sensor in the monitoring apparatus;
identifying, based upon the motion sensor signal, one or more periods of motion of the monitoring apparatus;
selectively obtaining and storing segments of the one or more PPG signals based on a temporal relationship between the segments of the one or more PPG signals and the identified one or more periods of motion;
determining that at least one segment of the one or more PPG signals is indicative of an arrhythmia event; and
generating, responsive to determining that the at least one segment of the one or more PPG signals is indicative of the arrhythmia event, a notification indicating that a user of the monitoring apparatus should obtain an electrocardiogram (ECG) measurement.

2. The method of claim 1 , wherein the temporal relationship indicates that the selectively obtained and stored segments of the one or more PPG signals do not correspond to the identified one or more periods of motion.

3. The method of claim 1 , further comprising:
generating and storing, based upon the segments of the one or more PPG signals, PPG waveform data identifying waveform characteristics associated with the one or more PPG signals; and
generating and storing, based on the PPG waveform data, arrhythmia event data describing one or more arrhythmia events.

4. The method of claim 3 , wherein the PPG waveform data includes a peak-to-peak dataset comprising one or more interval values representing time intervals between one or more successive peaks in the one or more PPG signals.

5. The method of claim 3 , wherein the arrhythmia event data describes one or more arrhythmia types and arrhythmia durations that are associated with the one or more arrhythmia types.

6. The method of claim 1 , wherein the motion sensor signal comprises one or more signals selected from the group consisting of: an accelerometer sensor signal from an accelerometer, an altitude signal from an altimeter, and a gyroscopic motion signal from a gyroscope.

7. The method of claim 1 , further comprising:
comparing a motion-related metric generated based upon the motion sensor signal to a specified motion threshold value;
determining, based on the comparing, that the one or more periods of motion indicate low motion; and
determining and storing one or more arrhythmia types and arrhythmia durations that are associated with the one or more arrhythmia types only during the one or more periods of motion that indicate low motion.

8. The method of claim 1 , further comprising:
comparing a motion-related metric generated based upon the motion sensor signal to a specified motion threshold value;
determining, based on the comparing, that the one or more periods of motion indicate sleep; and
determining and storing one or more arrhythmia types and arrhythmia durations that are associated with the one or more arrhythmia types only during the one or more periods of motion that indicate sleep.

9. The method of claim 1 , further comprising:
comparing a motion-related metric generated based upon the motion sensor signal to a specified motion threshold value;
determining, based on the comparing, that the one or more periods of motion indicate high motion; and
determining and storing, responsive to determining that the one or more periods of motion indicate high motion, one or more arrhythmia types and arrhythmia durations that are associated with the one or more arrhythmia types only during additional time periods that do not correspond to the one or more periods of motion that indicate high motion.

10. The method of claim 1 , further comprising:
comparing a motion-related metric generated based upon the motion sensor signal to a specified motion threshold value;
determining, based upon the comparing, that the one or more periods of motion indicate exercise; and
determining and storing, responsive to determining that the one or more periods of motion indicate exercise, one or more arrhythmia types and arrhythmia durations that are associated with the one or more arrhythmia types only during additional time periods that do not correspond to the one or more periods of motion that indicate exercise.

11. The method of claim 10 , further comprising:
obtaining, before the determining that the one or more periods of motion indicate exercise, the one or more PPG signals at a first temporal resolution;
determining, based upon the motion sensor signal, that the one or more periods of motion indicating exercise have ended and are followed by one or more periods of low motion; and
modifying, responsive to the determining that the one or more periods of motion indicating exercise have ended and are followed by one or more periods of low motion, a temporal resolution configuration parameter of the monitoring apparatus to cause the one or more PPG signals associated with the one or more periods of low motion to be obtained at a second temporal resolution that is higher than the first temporal resolution.

12. The method of claim 11 , further comprising classifying, based on the obtained one or more PPG signals associated with the one or more periods of low motion, a portion of the one or more PPG signals as representing success or failure in a clinical stress test.

13. The method of claim 10 , further comprising:
determining, based upon the motion sensor signal, that the one or more periods of motion indicating exercise have ended and are followed by one or more periods of low motion; and
determining and storing, responsive to determining that the one or more periods of motion indicating exercise have ended and are followed by the one or more periods of low motion, one or more arrhythmia types and arrhythmia durations that are associated with the one or more arrhythmia types during the one or more periods of low motion that follow the one or more periods of motion indicating exercise.

14. The method of claim 1 , further comprising:
comparing a motion-related metric generated based upon the motion sensor signal to a specified motion threshold value;
determining, based upon the comparing, that the one or more periods of motion indicate exercise; and
identifying, responsive to determining that the one or more periods of motion indicate exercise, an instance of chronotropic incompetence based on one or more heart rate values measured during the one or more periods of motion that indicate exercise.

15. The method of claim 1 , further comprising detecting one or more low amplitude PPG signals in the one or more PPG signals and, in response thereto, classifying a portion of the one or more PPG signals corresponding to the one or more low amplitude PPG signals as representing an arrhythmia.

16. The method of claim 1 , further comprising:
detecting, based upon the motion sensor signal, a period of low motion of the apparatus consistent with sleep of a user over a specified time sufficient to permit detection of sleep apnea;
detecting, based on the one or more PPG signals, an indication of bradycardia; and
marking, responsive to detecting the indication of bradycardia, a portion of the one or more PPG signals corresponding to the period of low motion as representing bradycardia.

17. The method of claim 15 , further comprising marking the portion of the one more PPG signals representing sleep

Assignees

• Fitbit Inc

Inventors

• Heneghan Conor
• Pantelopoulos Alexandros
• Venkatraman Subramaniam

Classifications

• A61B5/7282

  Event detection, e.g. detecting unique waveforms indicative of a medical condition (cough events A61B5/0823; seizures A61B5/4094; sleep apnoea A61B5/4818) · CPC title

• A61B5/1118

  Determining activity level · CPC title

• A61B5/02416 Primary

  using photoplethysmograph signals, e.g. generated by infrared radiation (A61B5/14552 takes precedence) · CPC title

• A61B5/002

  Monitoring the patient using a local or closed circuit, e.g. in a room or building (A61B5/0017 takes precedence) · CPC title

• A61B5/721 Primary

  using a separate sensor to detect motion or using motion information derived from signals other than the physiological signal to be measured · CPC title