Method and Apparatus for Phrenic Nerve Activation Detection with Respiration Cross-Checking

• US 20100305638A1
• Filed: 05/26/2010
• Published: 12/02/2010
• Est. Priority Date: 05/27/2009
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: McCabe, Aaron R., Rockweiler, Holly E., Laughner, Jacob L.
• Granted Patent: US 9,149,642 B2
• Time in Patent Office: Days
• US Class Current: 607/11
• CPC Class Codes: A61N 1/36521 the parameter being derived from measurement of an electrical impedance
• CPC Class Codes: A61N 1/36542 controlled by body motion, e.g. acceleration
• CPC Class Codes: A61N 1/3706 Pacemaker parameters stimulation threshold A61N1/371

Abstract

The present invention concerns phrenic nerve activation detection algorithms for characterization of phrenic nerve activation and phrenic nerve activation avoidance in cardiac pacing therapy.

Various embodiments concern receiving a respiration signal indicative of respiratory activity of the patient, identifying respiratory phases based on the respiration signal, delivering cardiac pacing pulses within each of the identified respiratory phases, receiving a phrenic nerve activation signal indicative of activation of the patient'"'"'s phrenic nerve, analyzing the phrenic nerve stimulation signal to determine if one or more of the pacing pulses activated the phrenic nerve of the patient, and determining if at least one of the delivered pacing pulses activated the phrenic nerve of the patient based on the phrenic nerve activation signal indicating activation of the patient'"'"'s phrenic nerve associated with delivery of the at least one cardiac pacing pulse.

Claims

1. A cardiac rhythm management system for phrenic nerve activation characterization, comprising:

an implantable cardiac pacing device having a plurality of electrodes configured for implantation in a patient;

circuitry configured to output a plurality of cardiac pacing pulses through the electrodes and modify one or more pacing parameters of the plurality of cardiac pacing pulses;

a phrenic nerve activation sensor configured to output a phrenic nerve activation signal indicative of activation of the patient'"'"'s phrenic nerve;

a respiration sensor configured to output a respiration signal indicative of inhalation and exhalation respiratory activity of the patient; and

a controller configured to execute program instructions stored in memory to cause the system to identify a plurality of different respiratory phases based on the respiration signal for multiple respiratory cycles of the patient, deliver the plurality of cardiac pacing pulses within each of the identified plurality of different respiratory phases, and analyze the phrenic nerve stimulation signal to determine if one or more of the delivered plurality of pacing pulses activated the phrenic nerve of the patient based on the phrenic nerve activation signal.

2. The cardiac rhythm management system of claim 1, wherein the plurality of different respiratory phases comprises inhalation, peak inhalation, exhalation, and peak exhalation phases, and wherein the phrenic nerve activation signal is analyzed to determine whether phrenic nerve stimulation occurred for any of the inhalation, peak inhalation, and exhalation phases.

3. The cardiac rhythm management system of claim 1, wherein the controller is further configured to execute stored program instructions to cause the system to:

perform a scan-down test comprising delivering successive sets of pacing pulses of decreasing energy until pacing parameter settings are identified that do not activate the patient'"'"'s phrenic nerve during any of the plurality of respiratory phases for a set of pacing pulses, each set of pacing pulses being delivered such that one or more pulses are delivered in each of the plurality of different respiratory phases and the pulses of each set of pacing pulses have common pulse amplitude and duration parameters; and

deliver a cardiac pacing pulse therapy using pacing parameter settings based on the identified pacing parameter settings.

4. The cardiac rhythm management system of claim 3, wherein the controller is further configured to execute stored program instructions to cause the system to:

perform an automatic ventricular threshold test comprising delivering successive pacing pulses of changing energy until a cardiac capture threshold is identified; and

set pacing pulse therapy parameters for the cardiac pacing pulse therapy equal to or greater than the capture threshold and equal to or less than the identified pacing parameter settings for which the set of pacing pulses did not activate the patient'"'"'s phrenic nerve for any of the different respiratory phases.

5. The cardiac rhythm management system of claim 1, wherein the controller is further configured to execute stored program instructions to cause the system to:

perform a scan-up test comprising delivering successive sets of pacing pulses of increasing energy until pacing parameter settings are identified that do activate the patient'"'"'s phrenic nerve during at least one of the plurality of respiratory phases, each set of pacing pulses being delivered such that one or more pulses are delivered in each of the plurality of different respiratory phases and the pulses of each set of pacing pulses have common pulse amplitude and duration parameters; and

deliver a cardiac pacing pulse therapy using pacing parameter settings having an energy parameter less than that of the identified pacing parameter settings.

6. The cardiac rhythm management system of claim 5, wherein the controller is further configured to execute stored program instructions to cause the system to:

perform an automatic ventricular threshold test comprising delivering successive pacing pulses of changing energy until a cardiac capture threshold is identified; and

set pacing pulse therapy parameters for the cardiac pacing pulse therapy equal to or greater than the capture threshold and equal to or less than the identified pacing parameter settings for which the set of pacing pulses did activate the patient'"'"'s phrenic nerve for at least one of the different respiratory phases.

7. The cardiac rhythm management system of claim 1, wherein the controller is further configured to execute stored program instructions to cause the system to increase or decrease a pacing pulse energy parameter for one or more of the plurality of cardiac pacing pulses between delivery of at least some of the plurality of pulses until a transition zone is identified, the transition zone comprising a range in the pacing pulse energy parameter within which the occurrence of phrenic nerve activation is dependent upon respiratory phase and outside of which the occurrence of phrenic nerve activation is not dependent upon respiratory phase.

8. The cardiac rhythm management system of claim 7, wherein the controller is further configured to execute stored program instructions to cause the system to select a cardiac pacing pulse parameter for cardiac therapy delivery that is below the parameter range of the identified transition zone and deliver the cardiac therapy using the selected cardiac pacing pulse parameter.

9. The cardiac rhythm management system of claim 1, wherein the phrenic nerve activation sensor comprises an accelerometer and the respiration sensor comprises an impedance sensor.

10. The cardiac rhythm management system of claim 1, wherein the controller is further configured to execute stored program instructions to cause the system to deliver the plurality of cardiac pacing pulses according to a cardiac therapy schedule regimen irrespective of the respiratory phase of the patient.

11. The cardiac rhythm management system of claim 1, wherein the controller is further configured to execute stored program instructions to cause the system to modify one or both of AV delay and VV delay stimulation parameters based on the patient'"'"'s respiratory cycle to deliver at least one of the plurality of cardiac pacing pulses within one of the different respiratory phases.

12. A method for characterizing phrenic nerve stimulation in cardiac rhythm management therapy, comprising:

receiving a respiration signal indicative of inhalation and exhalation respiratory activity of the patient;

identifying a plurality of different respiratory phases based on the respiration signal for multiple respiratory cycles of the patient;

delivering a plurality of cardiac pacing pulses within each of the identified plurality of different respiratory phases;

receiving a phrenic nerve activation signal indicative of activation of the patient'"'"'s phrenic nerve;

analyzing the phrenic nerve stimulation signal to determine if one or more of the delivered plurality of pacing pulses activated the phrenic nerve of the patient; and

determining if at least one of the delivered pacing pulses activated the phrenic nerve of the patient based on the phrenic nerve activation signal indicating activation of the patient'"'"'s phrenic nerve associated with delivery of the at least one cardiac pacing pulse.

13. The method of claim 12, wherein identifying the plurality of different respiratory phases comprises identifying inhalation, peak inhalation, and exhalation phases for multiple respiratory cycles of the patient, and wherein determining if at least one of the delivered pacing pulses activated the phrenic nerve comprises determining if any pacing pulses having common energy parameters delivered during the inhalation, peak inhalation, and exhalation phases activated the phrenic nerve of the patient.

14. The method of claim 12, wherein delivering the plurality of cardiac pacing pulses within each of the identified plurality of different respiratory phases further comprises:

delivering successive sets of pacing pulses of decreasing energy, each set of pacing pulses being delivered such that one or more pulses are delivered in each of the plurality of different respiratory phases and the pulses of each set of pacing pulses have common pulse amplitude and duration parameters;

identifying pacing parameter settings that do not activate the patient'"'"'s phrenic nerve for any of the plurality of different respiratory phases based on a set of the successive sets of pacing pulses that did not activate the patient'"'"'s phrenic nerve; and

delivering a pacing pulse therapy using pacing parameter settings based on the identified pacing parameter settings.

15. The method of claim 14, further comprising:

identifying a cardiac capture threshold by performing an automatic ventricular threshold test comprising delivering successive pacing pulses of changing energy until cardiac capture is gained or lost; and

delivering a cardiac pacing pulse therapy using pacing pulse therapy parameters equal to or greater than the capture threshold and equal to or less than the identified pacing parameter settings that do not activate the patient'"'"'s phrenic nerve.

16. The method of claim 12, wherein delivering the plurality of cardiac pacing pulses within each of the identified plurality of different respiratory phases further comprises:

delivering successive sets of pacing pulses of increasing energy, each set of pacing pulses being delivered such that one or more pulses are delivered in each of the plurality of different respiratory phases and the pulses of each set of pacing pulses have common pulse amplitude and duration parameters;

identifying pacing parameter settings that do activate the patient'"'"'s phrenic nerve for at least one of the plurality of different respiratory phases based on a set of the successive sets of pacing pulses that did activate the patient'"'"'s phrenic nerve at least once; and

delivering a pacing pulse therapy using pacing parameter settings based on the identified pacing parameter settings.

17. The method of claim 16, further comprising:

identifying a cardiac capture threshold by performing an automatic ventricular threshold test comprising delivering successive pacing pulses of changing energy until cardiac capture is gained or lost; and

delivering a cardiac pacing pulse therapy using pacing pulse therapy parameters equal to or greater than the capture threshold and less than the identified pacing parameter settings that do activate the patient'"'"'s phrenic nerve.

18. The method of claim 12, wherein determining if at least one of the delivered pacing pulses activated the phrenic nerve of the patient further comprises increasing or decreasing a pacing pulse energy parameter for one or more of the plurality of cardiac pacing pulses between delivery of at least some of the plurality of pulses until a transition zone is identified, the transition zone comprising a range in the pacing pulse energy parameter within which the occurrence of phrenic nerve activation is dependent upon respiratory phase and outside of which the occurrence of phrenic nerve activation is not dependent upon respiratory phase.

19. The method of claim 18, further comprising:

selecting a cardiac pacing pulse energy parameter below the range of the identified transition zone; and

delivering a cardiac therapy using the selected cardiac pacing pulse energy parameter.

20. The method of claim 12, wherein delivering the plurality of cardiac pacing pulses within each of the identified plurality of different respiratory phases further comprises modifying one or both of AV delay and VV delay stimulation parameters based on the patient'"'"'s respiratory cycle to deliver at least one cardiac pacing pulse within each of the different respiratory phases.

21. A cardiac rhythm management system, comprising:

means for receiving a respiration signal indicative of inhalation and exhalation respiratory activity of the patient;

means for identifying a plurality of different respiratory phases based on the respiration signal for multiple respiratory cycles of the patient;

means for delivering a plurality of cardiac pacing pulses within each of the identified plurality of different respiratory phases;

means for receiving a phrenic nerve activation signal indicative of activation of the patient'"'"'s phrenic nerve;

means for analyzing the phrenic nerve stimulation signal to determine if one or more of the delivered plurality of pacing pulses activated the phrenic nerve of the patient; and

means for determining if at least one of the delivered pacing pulses activated the phrenic nerve of the patient based on the phrenic nerve activation signal indicating activation of the patient'"'"'s phrenic nerve associated with delivery of the at least one cardiac pacing pulse.