Implantable dual site cardiac stimulation device having independent automatic capture capability

• US 6,549,806 B1
• Filed: 10/05/2000
• Issued: 04/15/2003
• Est. Priority Date: 05/15/2000
• Status: Expired due to Fees

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Inventors: Kroll, Mark W.
• Primary Examiner(s): Jastrzab, Jeffrey R.
• Application Number:
  US09/684,625
• Time in Patent Office: 922 Days
• Field of Search: 607/9, 607/11, 607/27, 607/28, 607/29
• US Class Current: 607/27
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy
• CPC Class Codes: A61N 1/368 comprising more than one electrode co-operating with different heart regions A61N1/3622, A61N1/3627 take precedence
• CPC Class Codes: A61N 1/3712 Auto-capture, i.e. automatic adjustment of the stimulation threshold

Abstract

An improved device and method for automatically determining threshold detection and maintaining capture in a multiple, e.g., dual, site cardiac stimulation device. When multiple site stimulation is used, e.g., for treatment of congestive heart failure (CHF) or the like, the threshold stimulation energy level at each of the sites will typically be different and, in the case of a lead implanted in the coronary sinus (CS), threshold stimulation energy level may be significantly different, e.g., 50 times greater or more. Accordingly, embodiments of the present invention independently maintain capture for each site and, preferably, independently determine the threshold for each site. In a significant aspect of the present invention, a preferred device periodically determines the chronaxie and rheobase corresponding to a strength-duration curve for each site and sets initial controlled energy levels accordingly. Once each initial controlled energy level is determined, which preferably includes a safety margin, the controlled energy level is increased when a loss-of-capture criteria is met. Furthermore, power expended from the battery is minimized since each site is individually optimized.

Claims

1. A method for pacing a patient'"'"'s heart using a battery powered implantable stimulation device connected to at least two electrodes implanted in a patient'"'"'s heart wherein a first electrode is positioned to stimulate a chamber in the right side of the patient'"'"'s heart and the second electrode is positioned to stimulate a corresponding chamber in the left side of the patient'"'"'s heart, the method comprising the steps of:

periodically stimulating the right side of the patient'"'"'s heart with a first stimulation pulse having a first controlled energy level wherein the first controlled energy level is defined by a set of characteristics including a first amplitude component and a first duration component;

detecting the presence or absence of an evoked response generated by the right side of the patient'"'"'s heart in response to the first stimulation pulse during a first detection window;

increasing the first controlled energy level in response to a loss-of-capture criteria related to the absence of an evoked response from the right side of the patient'"'"'s heart;

periodically stimulating the left side of the patient'"'"'s heart with a second stimulation pulse having a second controlled energy level wherein the second controlled energy level is defined by a set of characteristics including a second amplitude component and a second duration component;

detecting the presence or absence of an evoked response generated by the left side of the patient'"'"'s heart in response to the second stimulation pulse during a second detection window;

increasing the second controlled energy level in response to a loss-of-capture criteria related to the absence of an evoked response from the left side of the patient'"'"'s heart;

wherein

the step of periodically stimulating the left side of the patient'"'"'s heart additionally comprises the step of setting a time between stimulating the left and right sides of the heart to a determined delay period from the stimulation of the right side of the patient'"'"'s heart by the first stimulation pulse;

periodically measuring the present output voltage of the battery which powers the implantable stimulation device; and

wherein

the steps of increasing the first and second controlled energy levels are dependent upon the first and second amplitude components and the present battery output voltage.

2. The method of claim 1 wherein:

the step of increasing the first controlled energy level comprises the steps of;

determining a proposed increased first amplitude component for generating a first stimulation pulse which will result in the presence of an evoked response from the right side of the patient'"'"'s heart;

making a first determination if the proposed increased first amplitude component will exceed a voltage corresponding to the present battery output voltage; and

varying the first amplitude component dependent upon the second amplitude component and the first determination; and

the step of increasing the second controlled energy level comprises the steps of;

determining a proposed increased second amplitude component for generating a second stimulation pulse which will result in the presence of an evoked response from the left side of the patient'"'"'s heart;

making a second determination if the proposed increased second amplitude component will exceed the voltage corresponding to the present battery output voltage; and

varying the second amplitude component dependent upon the first amplitude component and the second determination.

3. The method of claim 1 further comprising the step of setting the delay period to essentially 0.0 seconds.

4. The method of claim 1 further comprising the step of setting the delay period to cause the right side of the patient'"'"'s heart to be stimulated before the left side of the patient'"'"'s heart.

5. The method of claim 1 further comprising the step of setting the delay period to cause the left side of the patient'"'"'s heart to be stimulated before the right side of the patient'"'"'s heart.

6. The method of claim 1 further comprising the steps of:

periodically determining the chronaxie and rheobase corresponding to a strength-duration curve for the chamber on the right side of the patent'"'"'s heart;

setting the first controlled energy level to an initial first controlled energy level related to the strength-duration curve for the right side of the patient'"'"'s heart;

periodically determining the chronaxie and rheobase corresponding to a strength-duration curve for the chamber on the left side of the patient'"'"'s heart; and

setting the second controlled energy level to an initial second controlled energy level related to the strength-duration curve for the left side of the patent'"'"'s heart.

7. The method of claim 6 further comprising the steps of:

setting the initial first controlled energy level to an amplitude value based on the amplitude value of the rheobase and a duration value of the chronaxie for the determined values corresponding to the chamber on the right side of the patient'"'"'s heart; and

setting the initial second controlled energy level to a value based on the amplitude value of the rheobase and a duration value of the chronaxie for the determined values corresponding to the chamber on the left side of the patient'"'"'s heart.

8. The method of claim 7 wherein:

the setting the initial first controlled energy level step comprises setting the initial first controlled energy level to an amplitude value corresponding to twice the rheobase and a duration value of the chronaxie for the determined values corresponding to the chamber on the right side of the patient'"'"'s heart; and

the setting the initial second controlled energy level step comprises setting the initial second controlled energy level to an amplitude value corresponding to twice the rheobase and a duration value of the chronaxie for the determined values corresponding to the chamber on the left side of the patient'"'"'s heart.

9. The method of claims 7 wherein the steps of setting the initial first and second controlled energy levels are functions of a safety margin value.

10. The method of claim 1 further comprising the steps of:

periodically determining the chronaxie and rheobase corresponding to the strength-duration curve for the chamber on the right side of the patient'"'"'s heart;

periodically determining the chronaxie and rheobase corresponding to a strength-duration curve for the chamber on the left side of the patient'"'"'s heart; and

causing the periodically determining steps to occur at different times to avoid interactions between the two determinations.

11. The method of claim 1 wherein in response to detecting the absence of an evoked response on the right side of the patient'"'"'s heart and the left side of the patient'"'"'s heart, further including the step of delivering a backup pulse after a backup delay following delivery of the first of two stimulation pulses.

12. The method of claim 11 further comprising the step of delivering the backup pulse at an elevated energy level.

13. The method of claim 11 further comprising the step of delivering the backup pulse only to the right side of the patient'"'"'s heart.

14. The method of claim 11 further comprising the step of delivering the backup pulse only to the left side of the patient'"'"'s heart.

15. A method for pacing a patient'"'"'s heart using an implantable stimulation device connected to at least two electrodes implanted in a patient'"'"'s heart wherein a first electrode is positioned to stimulate the right ventricle of the patient'"'"'s heart and the second electrode is positioned to stimulate the left ventricle of the patient'"'"'s heart, the method comprising the steps of:

periodically stimulating the right ventricle of the patient'"'"'s heart with a first stimulation pulse having a first controlled energy level wherein the first controlled energy level is defined by a set of characteristics including a first amplitude component and a first duration component;

detecting the presence or absence of an evoked response generated by the right ventricle of the patient'"'"'s heart in response to the first stimulation pulse during a first detection window;

increasing the first controlled energy level in response to a loss-of-capture criteria related to the absence of an evoked response from the right ventricle of the patient'"'"'s heart;

periodically stimulating the left ventricle of the patient'"'"'s heart with a second stimulation pulse having a second controlled energy level wherein the second controlled energy level is defined by a set of characteristics including a second amplitude component and a second duration component;

detecting the presence or absence of an evoked response generated by the left ventricle of the patient'"'"'s heart in response to the second stimulation pulse during a second detection window;

increasing the second controlled energy level in response to a loss-of-capture criteria related to the absence of an evoked response from the left ventricle of the patient'"'"'s heart;

wherein

the step of periodically stimulating the left ventricle of the patient'"'"'s heart additionally comprises the step of setting a time between stimulating the left and right ventricles of the patient'"'"'s heart to a determined delay period from the stimulation of the right ventricle of the patient'"'"'s heart by the first stimulation pulse; and

periodically measuring the present output voltage of a battery which powers the implantable stimulation device; and

wherein

the steps of increasing the first and second controlled energy levels are dependent upon the first and second amplitude components and the present battery output voltage.

16. A method for pacing a patient'"'"'s heart using an implantable stimulation device connected to at least two electrodes implanted in a patient'"'"'s heart wherein a first electrode is positioned in the right ventricular apex to stimulate the right ventricle of the patient'"'"'s heart and the second electrode is positioned in the coronary sinus to stimulate the left ventricle of the patient'"'"'s heart, the method comprising the steps of:

periodically stimulating the right ventricle of the patient'"'"'s heart with a first stimulation pulse having a first controlled energy level wherein the first controlled energy level is defined by a set of characteristics including a first amplitude component and a first duration component;

detecting the presence or absence of an evoked response generated by the right ventricle of the patient'"'"'s heart in response to the first stimulation pulse during a first detection window;

increasing the first controlled energy level in response to a loss-of-capture criteria related to the absence of an evoked response from the right ventricle of the patient'"'"'s heart;

periodically stimulating the left ventricle of the patient'"'"'s heart with a second stimulation pulse having a second controlled energy level wherein the second controlled energy level is defined by a set of characteristics including a second amplitude component and a second duration component;

detecting the presence or absence of an evoked response generated by the left ventricle of the patient'"'"'s heart in response to the second stimulation pulse during a second detection window;

increasing the second controlled energy level in response to a loss-of-capture criteria related to the absence of an evoked response from the left ventricle of the patient'"'"'s heart;

wherein

the step of periodically stimulating the left ventricle of the patient'"'"'s heart additionally comprises the step of setting a time between stimulating the left and right ventricle of the patient'"'"'s heart to a determined delay period from the stimulation of the right ventricle of the patient'"'"'s heart by the first stimulation pulse; and

periodically measuring the present output voltage of a battery which powers the implantable stimulation device; and

wherein

the steps of increasing the first and second controlled energy levels are dependent upon the first and second amplitude components and the present battery output voltage.

17. An implantable cardiac stimulation device configured for stimulating a patient'"'"'s heart through at least two electrodes wherein a first electrode is positioned to stimulate a chamber in the right side of the patient'"'"'s heart and the second electrode is positioned to stimulate a corresponding chamber in the left side of the patient'"'"'s heart, the stimulation device comprising:

a first pulse generator configured for electrical coupling to the first electrode and configured to generate first stimulation pulses at a first controlled energy level to thereby stimulate the right side of the patient'"'"'s heart, wherein the first controlled energy level is defined by a set of characteristics including an amplitude component and a duration component;

a first detection circuit configured for electrical coupling to the first electrode and configured to receive cardiac signals for determining the presence or absence of an evoked response to each of the first stimulation pulses;

a second pulse generator configured for electrical coupling to the second electrode and configured to generate second stimulation pulses at a second controlled energy level to thereby stimulate the left side of the patient'"'"'s heart, wherein the second controlled energy level is defined by a set of characteristics including an amplitude component and a duration component;

a second detection circuit configured for electrical coupling to the second electrode and configured to receive cardiac signals for determining the presence or absence of an evoked response to each of the second stimulation pulses;

a controller coupled to the first and second pulse generators and the first and second detection circuits for adaptively determining the first controlled energy level in response to the signals detected by the first detection circuit and for adaptively determining the second controlled energy level in response to signals detected by the second detection circuit;

a battery for providing power to the first and second pulse generators that generate the first and second stimulation pulses; and

a voltage detector for detecting the present voltage level of the battery; and

wherein

the controller modifies the amplitude components of the first and second controlled energy levels dependent upon the present battery voltage level and the present first and second amplitude components.

18. The cardiac stimulation device of claim 17 wherein the controller periodically determines the chronaxie and rheobase corresponding to a strength-duration curve for the chamber on the right side of the patient'"'"'s heart and determines an initial first controlled energy level accordingly.

19. The cardiac stimulation device of claim 18 wherein the controller periodically determines the chronaxie and rheobase corresponding to a strength-duration curve for the chamber on the left side of the patient'"'"'s heart and determines an initial second controlled energy level accordingly.

20. The implantable cardiac stimulation device of claim 19 wherein the initial first and second controlled energy levels are selected to achieve a safety margin from the respective determined strength-duration curves, and wherein the controller determines the initial first and second controlled energy levels based upon a specified safety margin value.

21. The cardiac stimulation device of claim 17 wherein the controller periodically determines the chronaxie and rheobase corresponding to a strength-duration curve for the chamber on the left side of the patient'"'"'s heart and determines an initial second controlled energy level accordingly.

22. The implantable cardiac stimulation device of claim 17 wherein:

the controller increases the first controlled energy level in response to a loss-of-capture criteria related to the absence of an evoked response from the right side of the patient'"'"'s heart; and

the controller increases the second controlled energy level in response to a loss-of-capture criteria related to the absence of an evoked response from the left side of the patient'"'"'s heart.

23. The implantable cardiac stimulation device of claim 17 wherein the stimulation of the left side of the patient'"'"'s heart by the second stimulation pulse occurs at an interchamber delay period from the stimulation of the right side of the patient'"'"'s heart by the first stimulation pulse.

24. The implantable cardiac stimulation device of claim 23 wherein the interchamber delay period is set to a delay of essentially 0.0 seconds.

25. The implantable cardiac stimulation device of claim 23 wherein the interchamber delay period is set to cause the right side of the patient'"'"'s heart to be stimulated prior to the left side of the patient'"'"'s heart.

26. The implantable cardiac stimulation device of claim 23 wherein the interchamber delay period is set to cause the left side of the patient'"'"'s heart to be stimulated prior to the right side of the patient'"'"'s heart.

27. The implantable cardiac stimulation device of claim 25 wherein the right chamber of the patient'"'"'s heart is the right ventricle and the left chamber of the patient'"'"'s heart is the left ventricle.

28. The implantable cardiac stimulation device of claim 27 wherein the first electrode is positioned proximate to the right ventricular apex and the second electrode is positioned proximate to the coronary sinus.

29. An implantable cardiac stimulation device configured for stimulating the right and left sides of a patient'"'"'s heart, the stimulation device comprising:

means for generating first stimulation pulses at a first controlled energy level to thereby stimulate the right side of the patient'"'"'s heart, wherein the first controlled energy level is defined by a set of characteristics including an amplitude component and a duration component;

first detection means for determining the presence or absence of an evoked response to each of the first stimulation pulses;

means for generating second stimulation pulses at a second controlled energy level to thereby stimulate the left side of the patient'"'"'s heart, wherein the second controlled energy level is defined by a set of characteristics including an amplitude component and a duration component;

second detection means for determining the presence or absence of an evoked response to each of the second stimulation pulses; and

means for adaptively determining the first controlled energy level in response to the first detection means and for adaptively determining the second controlled energy level in response to the second detection means;

a battery to provide power to the implantable cardiac stimulation device; and

a voltage detector to detect the present voltage level of the battery; and

wherein

the controller modifies the amplitude components of the first and second controlled energy levels dependent upon the present battery voltage level and the present first and second amplitude components.