Method and apparatus for phrenic nerve activation detection with respiration cross-checking

Patent metadata

Field	Value
Publication number	US-9149642-B2
Application number	US-78755710-A
Country	US
Kind code	B2
Filing date	May 26, 2010
Priority date	May 27, 2009
Publication date	Oct 6, 2015
Grant date	Oct 6, 2015

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.

First claim

We claim:

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 a 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 each respiratory cycle of a plurality of respiratory cycles of the patient;
in response to identifying the plurality of different respiratory phases, deliver the plurality of cardiac pacing pulses such that at least some of the plurality of cardiac pacing pulses are delivered during each respiratory phase of the identified plurality of different respiratory phases;
analyze the phrenic nerve activation signal to determine if one or more of the delivered plurality of pacing pulses activated the phrenic nerve of the patient during one or more of the identified plurality of different respiratory phases based on the phrenic nerve activation signal; and
deliver a cardiac pacing pulse therapy using predetermined pacing parameter settings that do not induce phrenic nerve activation.

2. The cardiac rhythm management system of claim 1 , wherein the controller is further configured to execute stored program instructions to:
if it is determined that one or more of the delivered plurality of pacing pulses activated the phrenic nerve of the patient during one or more of the identified plurality of different respiratory phases, then:
change a pacing pulse energy parameter of the plurality of pacing pulses;
deliver the plurality of cardiac pacing pulses with the changed pacing pulse energy parameter to coincide with each phase of the identified plurality of different respiratory phases; and
analyze the phrenic nerve activation signal to determine if one or more of the delivered plurality of pacing pulses with the changed pacing pulse energy parameter activated the phrenic nerve of the patient during one or more of the identified plurality of different respiratory phases based on the phrenic nerve activation signal.

3. The cardiac rhythm management system of claim 2 , wherein the controller is further configured to execute stored program instructions to repeat the steps of claim 2 with different pacing pulse energy parameters until a pacing pulse energy parameter is identified where none of the delivered plurality of pacing pulses activated the phrenic nerve of the patient during each of the identified plurality of different respiratory phases.

4. The cardiac rhythm management system of claim 1 , wherein the controller is further configured to execute stored program instructions to cause the system to:
determine the pacing parameter settings by 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.

5. The cardiac rhythm management system of claim 4 , 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 determined 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.

6. 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.

7. The cardiac rhythm management system of claim 6 , 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.

8. 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.

9. The cardiac rhythm management system of claim 1 , wherein the controller is further configured to execute stored program instructions to cause the system to:
determine the pacing parameter settings by 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.

10. The cardiac rhythm management system of claim 9 , 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 determined 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.

11. 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.

12. 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.

13. The cardiac rhythm management system of claim 1 , wherein the controller is further con

Assignees

• Mccabe Aaron R
• Rockweiler Holly E
• Laughner Jacob L
• Cardiac Pacemakers Inc

Inventors

• Mccabe Aaron R
• Rockweiler Holly E
• Laughner Jacob L

Classifications

• A61N1/36521

  the parameter being derived from measurement of an electrical impedance · CPC title

• A61N1/3706 Primary

  Pacemaker parameters (stimulation threshold A61N1/371) · CPC title

• A61N1/36542

  controlled by body motion, e.g. acceleration · CPC title