Deriving Patient Activity Information from Sensed Body Electrical Information

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 device, the method comprising:

• acquiring an electrical waveform representing electrical potentials between at least two subcutaneous electrodes during each of a plurality of non-overlapping time periods, the waveform being acquired by a medical device coupled to the at least two subcutaneous electrodes, the medical device being implanted substantially under the skin of a patient and arranged to receive and record electrical signals generated by cardiac activity in the body;
• post-processing the acquired electrical waveform to determine a level of activity of the patient during each of the plurality of non-overlapping time periods by performing the following operations:
• (a) selecting one of the plurality of non-overlapping time periods;
• (b) identifying non-cardiac muscle activity events in the acquired electrical waveform that occurred during the selected time period;
• (c) aggregating the activity events identified in operation (b) to determine a period activity value that represents a level of activity of the patient during the selected time period;
• and
• (d) repeating operations (a)-(c) to select each of the time periods in the plurality of time periods;
• and
• displaying to a user a representation of the period activity value for at least two of the plurality of time periods.

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

• an implantable waveform acquisition module operable to acquire ECG waveforms from subcutaneous electrodes implanted in a body;
• a processing module to process the acquired ECG waveforms to identify non-cardiac muscle activity events;
• an accumulation module to determine an activity level for each of a plurality of time intervals, each activity level being determined from an aggregation of the identified non-cardiac muscle activity events;
• and
• a format module to render a graphical representation of the determined activity level for each of the plurality of time intervals.

A method of controlling a rate of application of electrical stimulation to a heart of a patient based on patient activity as determined from non-cardiac muscle electrical signals in electrocardiogram (ECG) waveform information collected by an implanted device, the method comprising:

• (a) receiving an electrical waveform using subcutaneous electrodes, the received electrical waveform comprising electrical signals generated by electrical activity of a heart in a patient during a selected time period;
• (b) determining a level of physical activity of the patient by identifying portions of the received electrical waveform that include signals indicative of non-cardiac muscular activity in the patient during the selected time period;
• and
• (c) adjusting a rate of electrical stimulation applied to the heart in response to changes in the determined level of physical activity.

A system for applying electrical stimulus to an organ in a patient, the stimulation being responsive to patient physical activity information determined by detecting non-cardiac muscle noise in electrocardiogram (ECG) waveform information collected by a device implanted in the patient, the system comprising:

• an implantable waveform acquisition module operable to acquire ECG waveforms from subcutaneous electrodes implanted in a body;
• a first processing module to process the acquired ECG waveforms to identify non-cardiac muscle activity events;
• a second processing module to determine an activity level from an aggregation of the identified non-cardiac muscle activity events;
• and
• a stimulation module to generate electrical stimulation to apply to an organ in the body based on the determined activity level.