Apparatus for spatially and temporally distributing cardiac electrical stimulation

• US 8,560,067 B2
• Filed: 10/31/2007
• Issued: 10/15/2013
• Est. Priority Date: 04/06/2000
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Salo, Rodney W., Spinelli, Julio C., KenKnight, Bruce H.
• Primary Examiner(s): Schaetzle, Kennedy
• Application Number:
  US11/931,779
• Publication Number:
  US 20080097538A1
• Time in Patent Office: 2,176 Days
• Field of Search: None
• US Class Current: 607/6
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions
• 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

Abstract

A cardiac electro-stimulatory device and method for operating same in which stimulation pulses are distributed among a plurality of electrodes fixed at different sites of the myocardium in order to reduce myocardial hypertrophy brought about by repeated pacing at a single site and/or increase myocardial contractility. In order to spatially and temporally distribute the stimulation, the pulses are delivered through a switchable pulse output configuration during a single cardiac cycle, with each configuration comprising one or more electrodes fixed to different sites in the myocardium.

Claims

1. Apparatus for cardiac therapy, the apparatus comprising:

a plurality of electrodes adapted for fixation to a heart chamber;

a control unit comprising pulse generating circuitry operable in a plurality of defined pulse output configurations, wherein each pulse output configuration activates a subset of the plurality of the electrodes, the circuitry adapted for outputting;

a first pulse type comprising pulses to provide cardiac contractility modulating non-excitatory stimulation pulses to a selected one of the plurality of pulse output configurations in order to stimulate the heart chamber during a refractory period, wherein the pulse generating circuitry is capable of separately generating pulses to one or more of a plurality of electrodes; and

a second pulse type comprising a defibrillation signal; and

a switching module adapted to switch the control unit between outputting different pulse types, wherein the switching module is responsive to a sensed time delay of a depolarization occurring in at least a portion of the heart.

2. Apparatus according to claim 1, wherein the pulse generating circuitry is further adapted for outputting a third pulse type comprising a pacing signal.

3. Apparatus according to claim 2, comprising at least one thoracic sensor adapted to provide an output signal related to a cardiac output parameter;

wherein the switching module is responsive to said output signal.

4. Apparatus according to claim 3, wherein the sensor measures a mean or a minimum heart rate over a time interval and the switching module is adapted to respond to the mean or the minimum heart rate measured over a time interval.

5. Apparatus according to claim 1, comprising at least one thoracic sensor adapted to provide an output signal related to a cardiac output parameter;

wherein the switching module is responsive to said output signal.

6. Apparatus according to claim 5, wherein the at least one thoracic sensor senses intra-thoracic impedance.

7. Apparatus according to claim 5, wherein the thoracic sensor comprises a respiration rate detector and the switching module is responsive to the respiration rate.

8. Apparatus according to claim 5, wherein the thoracic sensor is adapted to sense a condition correlative to edema and the switching module is responsive to the condition correlative to edema.

9. Apparatus according to claim 8, wherein the thoracic sensor is adapted to sense a change in a baseline thoracic impedance associated with fluid buildup in a portion of a thorax of a subject.

10. Apparatus according to claim 9, wherein the change in the baseline thoracic impedance comprises a decrease.

11. Apparatus according to claim 9, in which the baseline portion of the thoracic impedance is less than or equal to a cutoff frequency value that is between 0.01 Hz and 0.5 Hz inclusive.

12. Apparatus according to claim 11, in which the cutoff frequency value is approximately 0.1 Hz.

13. Apparatus according to claim 1, wherein the switching module operates according to a switching algorithm.

14. Apparatus according to claim 13, wherein the switching algorithm switches the control unit intermittently.

15. Apparatus according to claim 13, wherein the switching algorithm switches the control unit substantially on a beat-to-beat basis.

16. Apparatus according to claim 13, wherein the switching algorithm switches the control unit at a specified time interval.

17. Apparatus according to claim 13, wherein the switching algorithm switches the control unit after a specified number of heart beats.

18. Apparatus according to claim 1, wherein the switching module initiates or adjusts a cardiac management therapy.

19. Apparatus according to claim 18, in which the cardiac management therapy comprises a cardiac resynchronization therapy that coordinates a spatial nature of a depolarization associated with a heart contraction in at least one heart chamber.

20. Apparatus according to claim 18, in which the cardiac management therapy comprises delivering the pulses of non-excitatory electrical energy to a portion of a heart during a refractory time period of the portion of the heart.