System for and method of therapeutic stimulation of a patient's heart

• US 4,899,752 A
• Filed: 06/03/1988
• Issued: 02/13/1990
• Est. Priority Date: 10/06/1987
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Leonard Bloom
• Inventors: Cohen, Todd J.
• Primary Examiner(s): Jaworski, Francis
• Assistant Examiner(s): MANUEL, GEORGE C
• Application Number:
  US07/201,935
• Time in Patent Office: 620 Days
• Field of Search: 128/419 PG, 128/672, 128/419 P, 128/673
• US Class Current: 607/23
• CPC Class Codes: A61N 1/36564 controlled by blood pressure
• CPC Class Codes: A61N 1/3918 characterised by shock pathway, e.g. by electrode configuration

Abstract

A system for therapeutic stimulation of a patient'"'"'s heart includes means for varying the escape interval or rate of a means for producing pacing pulses. Pressure sensing means sense pressure at a site in the circulatory system of a patient. Signal producing means respond to output from the sensing means to develop a variable first signal representative of mean pressure at the site over a period of predetermined duration. Signal producing means respond to output from the sensing means for developing a second signal representing mean pressure at the site over a period of given duration less than the period of predetermined duration. Control signal producing means responsive to the first signal and to the second signal develop a control signal upon the first signal and the second signal differing by at least a predetermined amount. Control means, responsive to the control signal, control the means for varying the escape interval or rate of the means for producing pacing pulses. The escape interval or rate may be additionally controlled by a second control signal related to the activity level of the patient either conjointly or contemporaneously. A method of therapeutic stimulation of a patient'"'"'s heart is also disclosed. The method can be viewed as an analogue of the system.

Claims

1. In a system for therapeutic stimulation of a patient'"'"'s heart and which includes means for producing pacing pulses and means for varying the escape interval or rate of said means for producing pacing pulses, an improvement comprising means for sensing blood pressure at a site in the circulatory system of a patient to produce an output, means responsive to the output from the sensing means for developing a variable first signal representative of mean blood pressure at the site over a period of predetermined duration, means responsive to the output from the sensing means for developing a variable second signal representing mean blood pressure at the site over a period of given duration less than the period of predetermined duration, means responsive to the first signal and to the second signal for developing a control signal upon the first signal and the second signal differing by at least a predetermined amount, and means responsive to the control signal for controlling the means for varying the escape interval or rate of the means for producing pacing pulses.

2. The system of claim 1, wherein said means for sensing blood pressure at a site in a circulatory system comprises means for sensing right atrial blood pressure

3. The system of claim 1, wherein said means for sensing blood pressure at a site in a circulatory system comprises means for sensing right ventricular blood pressure

4. The system of claim 1, wherein said means for sensing blood pressure at a site in a circulatory system comprises means for sensing central venous blood pressure

5. The system of claim 1, wherein said means for sensing blood pressure at a site in a circulatory system comprises means for sensing left atrial blood pressure.

6. The system of claim 1, wherein said means for sensing blood pressure at a site in a circulatory system comprises means for sensing left ventricular blood pressure.

7. The system of claim 1, wherein said means for sensing blood pressure at a site in a circulatory system comprises means for sensing arterial blood pressure.

8. The system of claim 1, wherein said means responsive to the first signal and to the second signal for developing a control signal comprise a microprocessor for developing the control signal

9. In a system for therapeutic stimulation of a patient'"'"'s heart and which includes means for producing pacing pulses and means for varying the escape interval or rate of said means for producing pacing pulses, an improvement comprising means for sensing blood pressure at a site in the circulatory system of a patient to produce an output, means responsive to the output from the sensing means for developing a variable first signal representative of mean blood pressure at the site over a period of predetermined duration, means responsive to the output from the sensing means for developing a variable second signal representative of mean blood pressure at the site over a period of give duration less than the period of predetermined duration, means responsive to the first signal and to the second signal for developing a first control signal whenever the first signal and the second signal differ by at least a predetermined amount, means responsive to a signal dependent on at least one physiological variable for developing a second control signal, and means contemporaneously responsive to the first control signal and to the second control signal for conjointly controlling the means for producing pacing pulses for modifying the escape interval or rate thereof.

10. The system of claim 9, wherein said means for sensing blood pressure at a site in a circulatory system comprises means for sensing right atrial blood pressure.

11. The system of claim 9, wherein said means for sensing blood pressure at a site in a circulatory system comprises means for sensing right ventricular blood pressure.

12. The system of claim 9, wherein said means for sensing blood pressure at a site in a circulatory system comprises means for sensing central venous blood pressure.

13. The system of claim 9, wherein said means for sensing blood pressure at a site in a circulatory system comprises means for sensing left atrial blood pressure.

14. The system of claim 9, wherein said means for sensing blood pressure at a site in a circulatory system comprises means for sensing left ventricular blood pressure.

15. The system of claim 9, wherein said means for sensing blood pressure at a site in a circulatory system comprises means for sensing arterial blood pressure.

16. The system of claim 9, wherein said means responsive to the first signal and to the second signal for developing a control signal comprises a microprocessor for developing the control signal.

17. The system of claim 9, including means for sensing activity level of a patient as the physiological variable to produce an output, and means responsive to the output from the means for sensing activity level to develop the second control signal.

18. A method of therapeutic stimulation of a patient'"'"'s heart comprising:

sensing blood pressure at a site in circulation system of a patient;

comparing means sensed blood pressure at the site as determined over a period of predetermined duration with mean sensed blood pressure at the site as determined over a current period of given duration less than the duration of the period of predetermined duration to find if the determined mean blood pressures at the site differ by at least a predetermined amount; and

controlling the escape interval or rate of a pacing system whenever the mean pressures differ by at least the predetermined amount.

19. The method of claim 18, wherein the step of sensing blood pressure is constituted by sensing right atrial blood pressure.

20. The method of claim 18, wherein the step of sensing blood pressure is constituted by sensing right ventricular blood pressure.

21. The method of claim 18, wherein the step of sensing blood pressure is constituted by sensing central venous blood pressure.

22. The method of claim 18, wherein the step of sensing blood pressure is constituted by sensing left atrial blood pressure.

23. The method of claim 18, wherein the step of sensing blood pressure is constituted by sensing left ventricular blood pressure.

24. The method of claim 18, wherein the step of sensing blood pressure is constituted by sensing arterial pressure.

25. A method of therapeutic stimulation of a patient'"'"'s heart comprising:

sensing blood pressure at a site in circulatory system of a patient;

comparing means blood pressure at the site as determined over a period of predetermined duration with means blood pressure at the site as determined over a current period of given duration less than the duration of the period of predetermined duration to find if the determined means blood pressures at the site differ by at least a predetermined amount;

sensing at least one physiological variable of the patient; and

controlling the escape interval or rate of a pacing system contemporaneously based on the physiological variable and on the determined mean blood pressures at the site.

26. The method according to claim 25, wherein the step of sensing at least one physiological variable is constituted by sensing vibrational energy at a site in or on the patient and converting the sensed energy into an activity related signal.

27. The method of claim 25 wherein the step of sensing blood pressure is constituted by sensing right atrial blood pressure.

28. The method of claim 25, wherein the step of sensing blood pressure is constituted by sensing right ventricular blood pressure

29. The method of claim 25, wherein the step of sensing blood pressure is constituted by sensing central venous blood pressure.

30. The method of claim 25, wherein the step of sensing blood pressure is constituted by sensing left atrial blood pressure.

31. The method of claim 25, wherein the step of sensing blood pressure is constituted by sensing left ventricular blood pressure.

32. The method of claim 25, wherein the step of sensing blood pressure is constituted by sensing arterial blood pressure.

33. In a system for therapeutic stimulation of a patient'"'"'s heart and which includes means for producing pacing pulses and means for varying the escape interval or rate of said means for producing pacing pulses, an improvement comprising means for sensing blood pressure at a site in the circulatory system of a patient to produce an output, means responsive to the output from the sensing means for developing a variable first signal representative of mean blood pressure at the site over a period of predetermined duration, means responsive to output from the sensing means for developing a variable second signal representing means blood pressure at the site over a period of given duration less than the period of predetermined duration, means responsive to the variable first signal and to the variable second signal for developing a stored first signal upon the first signal and the second signal differing by at least a predetermined amount, means responsive to the stored first signal and to the second signal for developing a control signal upon the stored first signal and the second signal differing by at least a given amount, and means responsive to the control signal for controlling the means for varying the escape interval or rate of the means for producing pacing pulses.

34. The system according to claim 33, wherein the predetermined amount is greater than the given amount.

35. In a system for therapeutic stimulation of a patient'"'"'s heart and which includes mean for producing pacing pulses and means for varying the escape interval or rate of a means for producing pacing pulses, an improvement comprising means for sensing blood pressure at a site in the circulatory system of a patient to produce an output, means responsive to the output from the sensing means for developing a variable first signal representative of mean blood pressure at the site over a period of predetermined duration, means responsive to the output from the sensing means for developing a variable second signal representative of mean blood pressure at the site over a period of given duration less than the period of predetermined duration, means responsive to the variable first signal and to the variable second signal for developing a stored first signal upon the first signal and the second signal differing by at least a predetermined amount, means responsive to the first signal and to the second signal for developing a first control signal whenever the stored first signal and the second signal differ by at least a given amount, means responsive to a signal dependent on at least one physiological variable for developing a second control signal, and means contemporaneously responsive to the first control signal and to the second control signal for conjointly controlling the means for producing pacing pulses for modifying the escape interval or rate thereof, whereby the escape interval or rate may be determined contemporaneously by the at least one physiological variable and by hemodynamic pressure at a site in the circulatory system.

36. The system according to claim 35, wherein the predetermined amount is greater than the given amount.

37. A method of therapeutic stimulation of a patient'"'"'s heart comprising:

sensing blood pressure at a site in circulation system of a patient;

comparing mean sensed blood pressure at the site as determined over a period of predetermined duration with mean sensed blood pressure at the site as determined over a current period of given duration less than the duration of the period of predetermined duration to find if the determined mean pressures at the site differ by at least a predetermined amount;

storing a representation of the mean sensed blood pressure at the site as determined over a period of predetermined duration at the time the sensed mean blood pressures differed by at least the predetermined amount;

comparing the stored representation of the sensed mean blood pressure with mean sensed blood pressure at the site as determined over a current period of the given duration to determine if current means blood pressure at the site differs from the stored representation by at least a give amount; and

controlling the escape interval or rate of a pacing system whenever current mean blood pressure differs from the stored representation of mean blood pressure by at least the given amount.

38. A method of therapeutic stimulation of a patient'"'"'s heart comprising:

sensing blood pressure at a site in circulatory system of a patient;

comparing means blood pressure at the site as determined over a period of predetermined duration with mean blood pressure at the site as determined over a current period of given duration less than the duration of the period of predetermined duration to find it the determined mean blood pressures at the site differ by at least a predetermined amount;

storing a representation of the mean sensed blood pressure at the site as determined over a period of predetermined duration at the time the sensed mean blood pressures differed by at least the predetermined amount;

comparing the stored representation of the sensed mean blood pressure with mean sensed blood pressure at the site as determined over a current period of the given duration to determine if current mean blood pressure at the site differs from the stored representation by at least a given amount;

sensing at least one physiological variable of the patient; and

controlling the escape interval or rate of a pacing system contemporaneously based on the physiological variable and determine the current mean pressure differing from the stored representation of mean pressure by at least the given amount.

39. In a system for therapeutic stimulation of a patient'"'"'s heart and which includes means for varying escape interval or rate of a means for producing pacing pulses, an improvement comprising means for sensing hemodynamic pressure at a site in the circulatory system of a patient, means responsive to output from the sensing means for developing a variable first signal representative of mean pressure at the site over a period of predetermined duration, means responsive to output from the sensing means for developing a variable second signal representative of mean pressure at the site over a period of given duration less than the period of predetermined duration, means responsive to the variable first signal and to the variable second signal for developing a stored first variable signal upon the first variable signal and the second variable signal differing by at least a predetermined amount, means responsive to the first variable signal and to the second variable signal for developing a stored first variable signal upon the first variable signal and the second variable signal differing by at least a predetermined amount, means responsive to the first variable signal and to the second variable signal for developing a first control signal whenever the stored first variable signal and the second variable signal differ by at least a given amount, and means responsive to a signal dependent on at least one physiological variable for developing a second control signal, said means for varying escape interval or rate being contemporaneously responsive to the first control signal and to the second control signal for conjointly controlling the means for producing pacing pulses for modifying the escape interval or rate thereof;

whereby the escape interval or rate may be determined contemporaneously by said at least one physiological variable and said hemodynamic pressure at a site in the circulatory system.

40. The system according to claim 39, wherein the predetermined amount is greater than the given amount.