System and method for modulating the pacing rate based on patient activity and position

• US 6,351,672 B1
• Filed: 07/22/1999
• Issued: 02/26/2002
• Est. Priority Date: 07/22/1999
• Status: Expired due to Term

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Inventors: Bornzin, Gene A., Park, Euljoon, Mai, Junyu
• Primary Examiner(s): Schaetzle, Kennedy
• Application Number:
  US09/359,025
• Time in Patent Office: 950 Days
• Field of Search: 607/17, 607/18, 607/23, 607/19, 607/22, 607/21, 607/24-26
• US Class Current: 607/19
• CPC Class Codes: A61N 1/36542 controlled by body motion, e.g. acceleration

Abstract

A system and method are provided for compensating for the drop in blood pressure upon standing. Upon transition from prolonged sitting, lying down, or standing position, the pacemaker abruptly increasing its pacing rate upon postural transition. The pacing rate is abruptly increased to about 80-100 bpm in 20 seconds-one minute. The pacing rate then decreases slowly to another high rate in two or three minutes and then follows the metabolically indicated rate. This pacing rate is triggered whenever a patient stands after a prolonged reclined or supine/prone position as indicated by activity variance measurements.

Claims

1. An implantable cardiac stimulation device for adjusting a pacing rate in accordance with a patient'"'"'s orthostatic need, the device being adapted to be coupled to at least one implantable lead, the device comprising:

a physiologic sensor that senses a physiologic parameter indicative of the patient'"'"'s need for pacing rate adjustment and generates a physiological signal;

a pulse generator, coupled to the at least one implantable lead, that generates stimulation pulses; and

controller, connected to the physiologic sensor and the pulse generator, the controller being responsive to receipt of physiological signals from the sensor to detect a period of inactivity that lasts for at least a predetermined duration followed by an activity level that exceeds a preset threshold, and in response to said detection to control the pulse generator according to a predetermined pacing scheme.

2. The implantable stimulation device of claim 1, wherein:

the predetermined pacing scheme comprises an orthostatic compensation pacing rate that comprises abruptly increasing the pacing rate and slowly decreasing the pacing rate.

3. The implantable stimulation device of claim 2, wherein the orthostatic compensation pacing rate comprises increasing the pacing rate to approximately 80-100 beats per minute and slowly decreasing the rate over a time period.

4. The implantable stimulation device of claim 3, wherein the orthostatic need is determined from the physiological signal.

5. The implantable stimulation device of claim 4, wherein:

the orthostatic need is determined from the physiological signal such that the controller is configured to determine a patient activity level and a patient activity variance measurement from the physiological signal; and

the controller is further configured to determine the need for orthostatic compensation pacing when the patient activity variance measurement is below a first threshold for a predetermined time period and then the patient activity level is above a second threshold.

6. The implantable stimulation device of claim 1, wherein the physiologic sensor is an activity sensor.

7. The implantable stimulation device of claim 6, wherein the activity sensor is an AC accelerometer.

8. The implantable stimulation device of claim 1, wherein the physiologic sensor is an oxygen saturation sensor.

9. The implantable stimulation device of claim 1, wherein the physiologic sensor is one of an impedance sensor, IEGM and evoked response sensor.

10. The implantable stimulation device of claim 1, wherein the controller is further configured to trigger pacing pulses when the patient is not in orthostatic need at a pacing rate as determined from the physiological signal.

11. The implantable stimulation device of claim 10, wherein the controller is further configured to determine a metabolically indicated pacing rate and trigger pacing pulses at the metabolically indicated pacing rate.

12. The implantable stimulation device of claim 11, wherein:

the metabolically indicated pacing rate is determined from an activity indicated rate or a circadian base rate;

wherein the controller determines the activity indicated rate from the activity level and the circadian base rate is determined from the activity level and a plurality of activity variance measurements;

wherein the controller triggers the pulse generator at a pacing rate equal to the maximum of the orthostatic compensation pacing rate, the activity indicated rate, and the circadian base rate when the patient is in need of orthostatic compensation; and

wherein the controller triggers the pulse generator at a pacing rate equal to the maximum of the activity indicated rate and the circadian base rate when the patient is not in need of orthostatic compensation.

13. An implantable cardiac stimulation device for adjusting a pacing rate in accordance with a patients orthostatic need, the device being adapted to be coupled to at least one implantable lead, the device comprising:

a physiologic sensor means for sensing a physiologic parameter indicative of the patient'"'"'s need for pacing rate adjustment and generating a physiological signal;

a pulsing means, coupled to the at least one implantable lead, for generating stimulation pulses; and

control means, connected to the physiologic sensing means and the pulsing means, for detecting a period of inactivity that lasts a predetermined duration, followed by an activity level above a preset threshold based on the physiological signals, and triggering the pulse generator according to a predetermined pacing scheme in response thereto.

14. The implantable stimulation device of claim 13, wherein:

the predetermined pacing scheme comprises an orthostatic compensation pacing rate that comprises abruptly increasing the pacing rate and slowly decreasing the pacing rate.

15. The implantable stimulation device of claim 14, wherein the orthostatic compensation pacing rate comprises increasing the pacing rate to approximately 80-100 beats per minute and slowly decreasing the rate over a time period.

16. The implantable stimulation device of claim 15, wherein the orthostatic need is determined from the physiological signal.

17. The implantable stimulation device of claim 13, wherein the physiologic sensing means is an activity sensor.

18. The implantable stimulation device of claim 17, wherein the activity sensor is an AC accelerometer.

19. The implantable stimulation device of claim 13, wherein the physiologic sensing means is an oxygen saturation sensor.

20. The implantable stimulation device of claim 13, wherein the physiologic sensing means is one of an impedance sensor, IEGM and evoked response sensor.

21. The implantable stimulation device of claim 13, wherein the controlling means further comprises means for triggering pacing pulses when the patient is not in orthostatic need at a pacing rate as determined from the physiological signal.

22. The implantable stimulation device of claim 21, wherein the controlling means further comprises means for determining a metabolically indicated pacing rate and triggering pacing pulses at the metabolically indicated pacing rate.

23. The implantable stimulation device of claim 22, wherein:

the metabolically indicated pacing rate is an activity indicated rate or a circadian base rate;

wherein the controlling means further comprises means for determining the activity indicated rate from the activity level and the circadian base rate from the activity level and a plurality of activity variance measurements;

wherein the controlling means further comprises means for triggering the pulsing means at a pacing rate equal to the maximum of the orthostatic compensation pacing rate, the activity indicated rate, and the circadian base rate when the patient is in need of orthostatic compensation; and

wherein the controlling means further comprises means for triggering the pulsing means at a pacing rate equal to the maximum of the activity indicated rate and the circadian base rate when the patient is not in need of orthostatic compensation.

24. A method of adjusting a pacing rate, the adjustment being based upon the patient'"'"'s orthostatic need with an implantable stimulation device comprising a sense circuit for sensing a physiological parameter and generating physiologic signals, a pulse generation circuit for generating stimulation pulses, and a controller, connected to the sense circuit and the pulse generation circuit, that triggers the pulse generation circuit at a stimulation rate, and that controls the stimulation rate, the method comprising:

detecting the physiologic parameter and generating a physiologic signal indicative of the physiologic parameter;

processing physiologic signals to detect a period of inactivity that lasts a predetermined duration followed by an activity level above a preset threshold; and

triggering the pulse generator to pace at the orthostatic compensation pacing rate in response to detecting the period of inactivity followed by the activity level above the threshold.

25. The method of adjusting the pacing rate as set forth in claim 24, further comprising:

determining a metabolically indicated pacing rate from the activity level signal and the activity variance measurement;

triggering the pacing pulses at the maximum of the orthostatic compensation pacing rate and the metabolic pacing rate if the patient is in need of orthostatic compensation pacing; and

triggering pacing pulses at the metabolic pacing rate if the patient is not in need of orthostatic compensation pacing.

26. The method of adjusting the pacing rate as set forth in claim 25, wherein the orthostatic pacing rate abruptly increases the pacing rate to 80-100 bpm and then slowly decreases the pacing rate over a period of between about 20 seconds and one minute.

27. The method of adjusting the pacing rate as set forth in claim 24, wherein the orthostatic pacing rate abruptly increases the pacing rate to 80-100 beats per minute and then slowly decreases the pacing rate over a period of between about 20 seconds and one minute.

28. The method of adjusting the pacing rate as set forth in claim 24, wherein the orthostatic pacing rate abruptly increases the pacing rate to 80-100 beats per minute and then slowly decreases the pacing rate over a period of between about 20 seconds and one minute.

29. An implantable cardiac stimulation device for adjusting a pacing rate in accordance with a patient'"'"'s orthostatic need, the device being adapted to be coupled to at least one implantable lead, the device comprising:

a physiologic sensor that senses a physiologic parameter indicative of the patient'"'"'s need for pacing rate adjustment and generates a physiological signal, wherein the sensor comprises one of an oxygen saturation sensor, an impedance sensor, an IEGM sensor, and an evoked response sensor;

a pulse generator, coupled to the at least one implantable lead, that generates stimulation pulses; and

a controller, connected to the physiologic sensor and the pulse generator, configured to determine when the patient needs orthostatic compensation based on the physiological signal, and triggers the pulse generator at an orthostatic compensation pacing rate in response thereto.

30. An implantable cardiac stimulation device for adjusting a pacing rate in accordance with a patient'"'"'s orthostatic need, the device being adapted to be coupled to at least one implantable lead, the device comprising:

a physiologic sensor that senses a physiologic parameter indicative of the patient'"'"'s need for pacing rate adjustment and generates a physiological signal, wherein the sensor comprises an AC accelerometer;

a pulse generator, coupled to the at least one implantable lead, that generates stimulation pulses; and

a controller, connected to the physiologic sensor and the pulse generator, configured to determine when the patient needs orthostatic compensation based on the physiological signal, and triggers the pulse generator at an orthostatic compensation pacing rate in response thereto.