Implantable cardiac stimulation device and method for prolonging atrial refractoriness

• US 6,701,187 B1
• Filed: 02/01/2002
• Issued: 03/02/2004
• Est. Priority Date: 01/20/2000
• Status: Expired due to Fees

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Inventors: Boileau, Peter, Florio, Joseph J., Bornzin, Gene A., Sloman, Laurence S.
• Primary Examiner(s): Getzow, Scott M.
• Application Number:
  US10/061,567
• Time in Patent Office: 760 Days
• Field of Search: 607/4-28
• US Class Current: 607/14
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions
• CPC Class Codes: A61N 1/3956 Implantable devices for applying electric shocks to the heart, e.g. for cardioversion

Abstract

An implantable cardiac stimulation device, e.g., a pacemaker or an implantable cardioverter defibrillator (ICD), is provided which prolongs the atrial refractoriness of a heart. The implantable cardiac stimulation device includes a generator that delivers pacing pulses to an atrium of a heart and a detector that detects atrial activations of the heart. An inhibitor is coupled to the detector that inhibits the generator when an atrial activation is detected within an escape interval. A generator control coupled to the generator causes the generator to deliver a primary pacing pulse to the atrium at the end of the escape interval, absent an atrial activation being detected within the escape interval, and causes the generator to deliver a secondary pacing pulse to the atrium a delay time after an atrial activation is detected within the escape interval or the delivery of a primary pacing pulse to the atrium.

Claims

1. An implantable cardiac stimulation device, comprising:

a sensing system that senses spontaneous atrial activations;

a pulse generator that generates stimulation pulses to produce evoked atrial activations in the absence of the spontaneous atrial activations; and

a control circuit operative to trigger the pulse generator to re-stimulate the atrium during a period when the ventricles are refractory.

2. The implantable cardiac stimulation device of claim 1, further comprising:

a sensor that senses when the patient is at rest; and

wherein the control circuit triggers the pulse generator to re-stimulate the atrium when the patient is at rest.

3. The implantable cardiac stimulation device of claim 1, further comprising:

a detector that detects episodes of a high incidence of premature atrial activations; and

wherein the control circuit triggers the pulse generator to re-stimulate the atrium in response to the detection of an episode of a high incidence of premature atrial activations.

4. The implantable cardiac stimulation device of claim 1, further comprising:

timing circuitry that generates a predetermined atrial delay triggered by one of a spontaneous or an evoked atrial activations; and

wherein the control circuit is operative to trigger the pulse generator to re-stimulate the atrium during a period when the ventricles are refractory as determined by the predetermined atrial delay triggered by the particular atrial activation.

5. The implantable cardiac stimulation device of claim 4, wherein the predetermined atrial delay is at least approximately 120 milliseconds.

6. The implantable cardiac stimulation device of claim 4, wherein the predetermined atrial delay is less than approximately 300 milliseconds.

7. The implantable cardiac stimulation device of claim 4, wherein the control circuit is further operative to periodically adjust the predetermined atrial delay to ensure that the re-stimulation of the atrium does not cause a conducted R-wave.

8. An implantable cardiac stimulation device, comprising:

means for detecting atrial activations;

pulse generating means for generating stimulation pulses to evoke atrial activations in a demand mode; and

means for re-stimulating the atrium within a same cardiac cycle at a coupling interval following an initial atrial activation.

9. The implantable cardiac stimulation device of claim 8, further comprising:

means for sensing when the patient is at rest; and

wherein the re-stimulating means comprises means for re-stimulating the atrium when the patient is at rest.

10. The implantable cardiac stimulation device of claim 8, further comprising:

means for detecting periods of high incidence of premature atrial activations; and

wherein the re-stimulating means comprises means for re-stimulating the atrium in response to the detection of a period of a high incidence of premature atrial activations.

11. The implantable cardiac stimulation device of claim 8, further comprising:

means for determining an atrial delay triggered by one of a spontaneous or an evoked atrial activation; and

wherein the re-stimulating means comprises means for re-stimulating the atrium according to the atrial delay.

12. The implantable cardiac stimulation device of claim 11, wherein the atrial delay is at least approximately 120 milliseconds.

13. The implantable cardiac stimulation device of claim 11, wherein the atrial delay is less than approximately 300 milliseconds.

14. The implantable cardiac stimulation device of claim 11, further comprising:

means for periodically determining an appropriate value for the atrial delay time to ensure that the re-stimulation of the atrium does not cause a conducted R-wave.

15. In an implantable cardiac stimulation device, a method for increasing the time that the atria are in a refractory state, comprising:

generating stimulation pulses to evoke atrial activations in a demand mode;

detecting an initial atrial activation within a selected cardiac cycle; and

providing an additional atrial stimulation pulse within the selected cardiac cycle at a coupling interval following the initial atrial activation.

16. The method of claim 15, further comprising:

determining when the patient is at rest; and

enabling the providing step when the patient is at rest.

17. The method of claim 15, further comprising:

detecting periods of high incidence of premature atrial activations; and

triggering the providing step in response to the detection of a period of a high incidence of premature atrial activations.

18. The method of claim 15, further comprising:

determining an atrial delay triggered by one of a spontaneous or evoked atrial activation; and

triggering the providing step according to the atrial delay.

19. The method of claim 18, further comprising:

automatically determining an appropriate value for the atrial delay to ensure that the additional atrial stimulation pulse does not cause a conducted R-wave.