Method and apparatus for monitoring heart rate

• US 6,714,811 B1
• Filed: 12/01/1999
• Issued: 03/30/2004
• Est. Priority Date: 03/05/1999
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Olson, Walter H., Ousdigian, Kevin T., Padmanabhan, Vasant, Stone, Karen A.
• Primary Examiner(s): Bockelman, Mark
• Application Number:
  US09/452,659
• Time in Patent Office: 1,581 Days
• Field of Search: 600/374, 600/508-521, 607/9, 607/19
• US Class Current: 600/509
• CPC Class Codes: A61B 2560/0431 Portable apparatus, e.g. comprising a handle or case
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/11 Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb for measuring pulse A61B5/02 ;A61B5/1038 takes precedence; motion detection to correct for motion artifacts in physiological signals A61B5/721

Abstract

A monitoring device for implant in a patient'"'"'s body. The device is provided with a physiologic sensor generating output signals, which signals are stored as numerical values. The device defines first monitoring periods limited to time periods during successive nights during which the patient is likely to be asleep, stores the numerical values generated during the first monitoring periods in a memory and calculates values reflecting general levels of the numerical values during the first monitoring periods. The device may also or alternatively define second monitoring periods limited to time periods during successive daytime and store numerical values generated during the second monitoring periods. The physiologic sensor may be an electrogram amplifier or other sensor indicative of metabolic demand for oxygenated blood, such as an activity sensor. The calculated values reflecting general levels of the numerical values generated during the monitoring periods may be average values, such as mean values or over-all total values, depending upon the sensor employed.

Claims

1. A monitoring device for implant in a patient'"'"'s body, comprising:

a cardiac electrogram amplifier;

a sensing electrogram amplifier;

timing means for defining first monitoring periods limited to time periods during successive nights during which the patient is likely to be sleep;

memory means for storing heart intervals between depolarizations of the patient'"'"'s heart sensed by the amplifier during the first monitoring periods; and

means for calculating average heart rates during the first monitoring periods.

2. A device according to claim 1 wherein the timing means further comprises means for defining second monitoring periods limited to time periods during successive daytime periods and wherein the memory means further comprises means for storing heart intervals between depolarizations of the patient'"'"'s heart sensed by the amplifier during the second monitoring periods and wherein the calculating means further comprises means for calculating average heart rates during the second monitoring periods.

3. A device according to claim 1, further comprising a sensor responsive to the patients level of exercise and wherein the calculating means comprises means responsive to the sensor for calculating average heart rates based only on heart intervals stored while the patient is at rest.

4. A device according to claim 1, further comprising means for rejecting heart intervals occurring during tachyarrhythmias and wherein the calculating means comprises means for calculating average heart rates based on heart intervals not rejected.

5. A device according to claim 4 wherein the calculating means comprises means for determining total durations of non-rejected heart intervals during the first monitoring periods and means for preventing calculation of an average heart rate if the total duration of non-rejected heart intervals during a first monitoring period is less than a required duration.

6. A monitoring device for implant in a patient'"'"'s body, comprising:

a sensor responsive to the patient'"'"'s level of exercise;

a cardiac electrogram amplifier;

a sensing electrode coupled to an input of the amplifier;

means for defining first monitoring periods limited to time periods during which the sensor indicates that the patient is likely to be at rest;

memory means for storing heart intervals between depolarizations of the patient'"'"'s heart sensed by the amplifier during the first monitoring periods.

7. A device according to claim 6, further comprising means for rejecting heart intervals occurring during tachyarrhythmias and wherein the calculating means comprises means for calculating average heart rates based on heart intervals not rejected.

8. A device according to claim 7 wherein the calculating means comprises means for determining total durations of non-rejected heart intervals during the first monitoring periods and means for preventing calculation of an average heart rate if the total duration of non-rejected heart intervals during a first monitoring period is less than a required duration.

9. A monitoring device for implant in a patient'"'"'s body, comprising:

a cardiac electrogram amplifier;

a sensing electrode coupled to an input of the amplifier;

means for defining first monitoring periods limited to successive daytime periods;

memory means for storing heart intervals between depolarizatons of the patient'"'"'s heart sensed by the amplifier during the first monitoring periods; and

means for calculating average heart rates during the first monitoring periods.

10. A device according to claim 9, further comprising a sensor responsive to the patients level of exercise and wherein the calculating means comprises means responsive to the sensor for calculating average heart rates based only on heart intervals stored while the patient is at rest.

11. A device according to claim 9, further comprising means for rejecting heart intervals occurring during tachyarrhythmias and wherein the calculating means comprises means for calculating average heart rates based on heart intervals not rejected.

12. A device according to claim 11 wherein the calculating means comprises means for determining total durations of non-rejected heart intervals during the first monitoring periods and means for preventing calculation of an average heart rate if the total duration of non-rejected heart intervals during a first monitoring period is less than a required duration.

13. A monitoring device for implant in a patients body, comprising:

a physiologic sensor generating an output signal;

means for generating numerical values indicative of sensor output signals;

timing means for defining first monitoring periods limited to time periods during successive nights during which the patient is likely to be asleep;

memory means for storing the numerical values generated during the first monitoring periods; and

means for calculating values reflecting general levels of the numerical values during the first monitoring periods.

14. A device according to claim 13 wherein the timing means further comprises means for defining second monitoring periods limited to time periods during successive daytime periods and wherein the memory means further comprises means for storing numerical values generated during the second monitoring periods and wherein the calculating means further comprises means for calculating values reflecting general levels of the numerical values during the second monitoring periods.

15. A device according to claim, 13 wherein the physiologic sensor is an electrogram amplifier.

16. A device according to claim 13 wherein the physiologic sensor is a sensor indicative of metabolic demand for oxygenated blood.

17. A device according to claim 16 wherein the physiologic sensor is an activity sensor.

18. A device according to claim 13 wherein the calculated values reflecting general levels of the numerical values are averages.

19. A device according to claim 13 wherein the calculated values reflecting general levels of the numerical values are totals.