Cardiac pacing apparatus and method for continuous capture management

• US 20040260352A1
• Filed: 06/17/2003
• Published: 12/23/2004
• Est. Priority Date: 06/17/2003
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Combs, William J., Rueter, John C.
• Granted Patent: US 7,831,303 B2
• Time in Patent Office: Days
• US Class Current: 607/28
• CPC Class Codes: A61N 1/3712 Auto-capture, i.e. automatic adjustment of the stimulation threshold

Abstract

An implantable cardiac stimulation system and method having continuous capture management capabilities are provided. Continuous capture management is realized by continuously monitoring for secondary effects of loss of capture, thereby effectively providing continuous capture management in any heart chamber without encountering the limitations normally associated with evoked response sensing. A pacing threshold search is triggered upon detecting a secondary indicator of loss of capture. Secondary indicators of loss of capture may be lead-related changes, changes related to the occurrence of atrial sensed events, changes related to the occurrence of ventricular sensed or paced events, and/or changes related to a monitored physiological condition.

Claims

1. A method of providing capture management in an implantable medical device, the method comprising:

delivering pacing therapy through at least one lead;

monitoring for secondary indicators of loss of capture; and

performing a pacing threshold search if a secondary indicator of loss of capture is monitored.

2. The method of claim 1 further comprising:

determining whether the secondary loss of capture indicator more likely indicates a loss of capture in an atrium or more likely indicates a loss of capture in a ventricle; and

performing the pacing threshold search on the atrium first if the secondary loss of capture indicator more likely indicates a loss of capture in an atrium and performing the pacing threshold search on the ventricle first if the secondary loss of capture indicator more likely indicates a loss of capture in an ventricle.

3. The method of claim 1, wherein performing the threshold test includes first performing the threshold test on a ventricle.

4. The method of claim 3, wherein performing the threshold test includes only performing the threshold test on an atrium if the threshold test on the ventricle fails to indicate a loss of capture.

5. The method of claim 3, wherein performing the threshold test includes performing the threshold test on the atrium when the threshold test indicates loss of capture if the monitoring continues to provide a secondary indicator of loss of capture after a ventricular threshold has been corrected.

6. The method of claim 1, wherein the secondary indicators of loss of capture include lead related indicators.

7. The method of claim 6, wherein the lead related indicators include lead impedance changes or lead configuration changes.

8. The method of claim 1, wherein the secondary indicators of loss of capture include atrial sensed events.

9. The method of claim 8, wherein the atrial sensed invents include one of the following:

an increased frequency of sensed atrial refractory events, an increased frequency of PVARP extensions, a detected pattern of retrograde conduction, an increased frequency of mode switching, or an increased duration of non-atrial tracking episodes.

10. The method of claim 1, wherein the secondary indicators of loss of capture include ventricular sensed events.

11. The method of claim 10, wherein the ventricular sensed events include an increase in the frequency of ventricular pacing or an increase in the frequency of PVC'"'"'s.

12. The method of claim 1, wherein the secondary indicators of loss of capture include:

detecting sleep apnea, detecting Cheyne-Stokes breathing, detecting variation in blood pressure, or detecting a decrease in blood oxygen saturation.

13. The method of claim 1, wherein capture management is monitored on a continuous basis.

14. The method of claim 1, further comprising:

responding to a secondary indicator of loss of capture if the pacing threshold search fails to indicate a loss of capture.

15. The method of claim 14 wherein responding includes:

adjusting sensitivity levels, adjusting a refractory period, adjusting a blanking period, adjusting a pacing mode, adjusting the delivery of pacing therapy.

16. An implantable medical device comprising:

a pulse generator for delivering pacing pulses;

at least one lead in electrical communication with the pulse generator for delivering the pacing pulse to cardiac tissue; and

a microprocessor for controlling the pulse generator, receiving sensed data from the at least one lead, wherein the sensed data includes a secondary indicator loss of capture, and performing a pacing threshold search when the secondary indicator of loss of capture is sensed.

17. An implantable medical device comprising:

a pulse generator;

at least one lead coupled with the pulse generator for delivering therapy;

sensing means for continuously sensing secondary indicators of loss of capture; and

controller means for receiving an indication of a secondary indicator of loss of capture and conducting a pacing threshold search for the at least one lead.

18. An implantable medical device having a pulse generator, a lead coupled with the pulse generator and a microprocessor coupled with the pulse generator, the microprocessor including programming to continuously monitor threshold settings, the programming comprising:

a sensing module for receiving secondary indicators of loss of capture;

an analysis module for triggering the performance of a pacing threshold search when the sensing module provides data that a secondary indicator of loss of capture has been detected and determining whether the secondary indicator of loss of capture was generated by a loss of capture after the pacing threshold search has been conducted.

19. The implantable medical device of claim 18, wherein the analysis module first conducts the pacing threshold search on a ventricular lead.

20. The implantable medical device of claim 19, wherein the analysis module conducts the pacing threshold search on an atrial lead if the search on the ventricular lead failed to indicate a loss of capture.