Deriving patient activity information from sensed body electrical information

• US 8,180,442 B2
• Filed: 12/14/2007
• Issued: 05/15/2012
• Est. Priority Date: 12/14/2007
• Status: Expired due to Fees

• Current Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Original Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Inventors: Belalcazar, Andres, Chen, Ji
• Primary Examiner(s): Layno, Carl H
• Assistant Examiner(s): Patel, Natasha
• Application Number:
  US11/956,884
• Publication Number:
  US 20090156908A1
• Time in Patent Office: 1,614 Days
• Field of Search: 600/546, 600/547
• US Class Current: 600/546
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/287 Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS]
• CPC Class Codes: A61B 5/4519 Muscles A61B5/389, A61B5/224 take precedence

Abstract

Electrodes of a subcutaneous monitoring system receive body electrical signals that indicate both cardiac and non-cardiac muscle activity. In general, non-cardiac muscle activity is often correlated with physical activity, and physical activity is typically a strong indicator of patient health. Exemplary systems and methods that detect non-cardiac muscle activity information in sensed body electrical waveforms may provide a diagnostic tool for monitoring physical activity level over time in patients that have subcutaneous monitoring systems. In an illustrative embodiment, systems and methods for presenting patient activity information in a graphical format over intervals of time include processing ECG waveform information to identify and to accumulate non-cardiac muscular activity information during each of the intervals of time. In various implementations, number, intensity, and/or duration of the events that are identified during a time interval may be accumulated and stored for subsequent recall.

Claims

1. A method of presenting physical activity information for an individual by detecting non-cardiac muscle noise in electrocardiogram (ECG) waveform information collected by an implanted medical device, the method comprising the steps of:

a) implanting a medical device within a patient, the medical device comprising at least a first subcutaneous electrode implanted in or adjacent to the patient'"'"'s heart and a second subcutaneous electrode implanted in or adjacent to non-cardiac muscle or fascia tissue of the chest, abdomen, back or neck regions of the patient;

b) acquiring a composite electrical waveform from the first and second subcutaneous electrodes, the composite electrical waveform comprising cardiac derived electrical signals generated by cardiac activity of the heart and non-cardiac derived electrical signals including both psychological and physiological data generated by non-cardiac muscle or fascia tissue of the patient during each of a plurality of non-overlapping time periods;

c) post-processing at least two of the acquired composite electrical waveforms by performing the following operations;

i) selecting one of the plurality of non-overlapping time periods;

ii) identifying non-cardiac muscle activity events in the acquired composite electrical waveform that occurred during the selected time period;

iii) aggregating the non-cardiac muscle activity events identified in operation ii) to determine a period activity value that represents a level of electrical activity of the patient during the selected time period; and

iv) repeating operations i)-iii) for a second one of the time periods in the plurality of time periods; and

d) displaying to a user a representation of the period activity value for the at least two time periods.

2. The method of claim 1 including transmitting data representing the acquired composite electrical waveform through the skin from the implanted medical device to a receiver module external to the body.

3. The method of claim 1 including providing a receiver module external to the body for receiving transmitted data from the medical device, the receiver module comprising a programming module storing programming information for the medical device.

4. The method of claim 1 including transmitting information about the period activity values through the skin from the implanted medical device to a receiver module external to the body.

5. The method of claim 1 including transmitting the acquired composite electrical waveform from a subcutaneous antenna implanted in the body.

6. The method of claim 1, wherein operation ii) further comprises high-pass filtering, rectifying, and smoothing of the acquired composite electrical waveform.

7. The method of claim 1, wherein operation ii) comprises comparing an amplitude of the frequency of the composite electrical waveform acquired during the selected time period to a threshold value.

8. The method of claim 7, wherein operation ii) further comprises comparing the acquired composite electrical waveform to at least one additional threshold value to identify non-cardiac muscle activity events in the acquired composite electrical waveform that occurred during the selected time period.

9. The method of claim 1, wherein operation iii) comprises counting the non-cardiac muscle activity events identified in operation ii).

10. The method of claim 1 including providing the period activity value being a function of an amplitude of each of the non-cardiac muscle activity events identified in operation ii).

11. The method of claim 1 including providing the period activity value being a function a duration of each of the non-cardiac muscle activity events identified in operation ii).

12. The method of claim 11, wherein, for each one of the plurality of time periods, the corresponding histogram represents in a first dimension a first period activity value based on a number of the non-cardiac muscle activity events identified in operation ii), and further represents in a second dimension a second period activity value based on an amplitude of each of the non-cardiac muscle activity events identified in operation ii).

13. The method of claim 11, wherein, for each one of the plurality of time periods, the corresponding histogram represents in a first dimension a first period activity value based on a number of the non-cardiac muscle activity events identified in operation ii), and further represents in a second dimension a second period activity value based on a duration of each of the non-cardiac muscle activity events identified in operation ii).

14. The method of claim 1 including providing the displayed representation comprising a histogram.

15. The method of claim 1 including providing the composite electrical waveform comprising the non-cardiac electrical signal as relatively high frequency signals superimposed on repeating cardiac electrical signal as relatively low frequency signals.

16. The method of claim 1 including displaying the non-cardiac electrical signals as an episode of relatively higher frequency signals superimposed on repeating cardiac electrical signals.

17. A method of presenting physical activity information for an individual by detecting non-cardiac muscle noise in electrocardiogram (ECG) waveform information collected by an implanted medical device, the method comprising the steps of:

a) implanting a medical device within a patient, the medical device comprising at least a first subcutaneous electrode implanted in or adjacent to the patient'"'"'s heart and a second subcutaneous electrode implanted in or adjacent to non-cardiac muscle or fascia tissue of the chest, abdomen, back or neck regions of the patient;

b) acquiring electrical waveforms from the first and second subcutaneous electrodes, the electrical waveforms comprising electrical activity signals generated by cardiac activity of the heart and non-cardiac electrical activity signals including both psychological and physiological data generated by the muscle or fascia tissue of the patient during each of a plurality of non-overlapping time periods;

c) post-processing at least two of the acquired electrical waveforms of the cardiac electrical activity signals and of the non-cardiac electrical activity signals by performing the following operations;

i) selecting one of the plurality of non-overlapping time periods;

ii) identifying non-cardiac muscle activity events in the acquired electrical waveforms that occurred during the selected time period;

iii) aggregating the non-cardiac muscle activity events identified in operation ii) to determine a period activity value that represents a level of electrical activity of the patient during the selected time period; and

iv) repeating operations i)-iii) for a second one of the time periods in the plurality of time periods; and

d) displaying to a user a representation of the period activity value for the at least two time periods.