Nerve signal differentiation in cardiac therapy

• US 8,639,327 B2
• Filed: 07/30/2010
• Issued: 01/28/2014
• Est. Priority Date: 04/29/2010
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Zhou, Xiaohong, Burnes, John Edward, Kornet, Lilian, Cornelussen, Richard N. M.
• Primary Examiner(s): Bertram, Eric D.
• Application Number:
  US12/848,019
• Publication Number:
  US 20120029587A1
• Time in Patent Office: 1,278 Days
• Field of Search: 607/9
• US Class Current: 607/9
• CPC Class Codes: A61N 1/36053 adapted for vagal stimulation A61N1/36114 takes precedence
• CPC Class Codes: A61N 1/36114 Cardiac control, e.g. by vagal stimulation stimulating the heart A61N1/362
• CPC Class Codes: A61N 1/36139 with automatic adjustment
• CPC Class Codes: A61N 1/3621 for treating or preventing abnormally high heart rate
• CPC Class Codes: A61N 1/36514 controlled by a physiological quantity other than heart potential, e.g. blood pressure controlled by two or more physical parameters A61N1/36585
• CPC Class Codes: A61N 1/3937 Monitoring output parameters
• CPC Class Codes: A61N 1/3987 characterised by the timing or triggering of the shock

Abstract

Methods of nerve signal differentiation, methods of delivering therapy using such nerve signal differentiation, and to systems and devices for performing such methods. Nerve signal differentiation may include locating two electrodes proximate nerve tissue and differentiating between efferent and afferent components of nerve signals monitored using the two electrodes.

Claims

1. A method of delivering therapy, wherein the method comprises:

monitoring physiological parameters of a patient, wherein the physiological parameters comprise electrical activity of the patient'"'"'s vagus nerve;

determining whether the monitored electrical activity of the patient'"'"'s vagus nerve comprises efferent activity;

analyzing the monitored physiological parameters, wherein analyzing the monitored physiological parameters comprises determining whether the efferent activity of the electrical activity of the patient'"'"'s vagus nerve is reduced over time; and

initiating or adjusting non-nerve stimulating cardiac therapy if the efferent activity of the electrical activity of the patient'"'"'s vagus nerve is reduced, wherein the non-nerve stimulating cardiac therapy comprises at least one of pacing therapy, cardiac resynchronization therapy, anti-tachycardia pacing, high-energy shock pulses for cardioversion/defibrillation therapy, bradycardia pacing, and drug therapy, wherein the method further comprises determining whether the monitored electrical activity of the patient'"'"'s vagus nerve comprises afferent activity, and wherein determining whether the efferent activity of the electrical activity of the patient'"'"'s vagus nerve is reduced comprises comparing the efferent activity to the afferent activity.

6. The method of any of claims 1 to 5, wherein determining whether the efferent activity of the electrical activity of the patient'"'"'s vagus nerve is reduced comprises comparing the pulses per second of the efferent activity to a selected value.

7. The method of any of claims 1 to 5, wherein determining whether the efferent activity of the electrical activity of the patient'"'"'s vagus nerve is reduced comprises comparing the pulses per second of presently-monitored efferent activity to the pulses per second of previously-monitored efferent activity.

8. The method of any of claims 1 to 5, wherein the physiological parameters further comprise electrical activity of the patient'"'"'s heart, and wherein the method further comprises:

providing a function relating the status of the patient'"'"'s vagus nerve to the electrical activity of the patient'"'"'s heart for use in therapy,

assessing a status of the patient'"'"'s vagus nerve using the monitored electrical activity of the patient'"'"'s heart using the function, and

initiating or adjusting cardiac therapy to the patient based on the assessed status of the patient'"'"'s vagus nerve.

9. The method of any of claims 1 to 5, wherein determining whether the monitored electrical activity of the patient'"'"'s vagus nerve comprises efferent activity comprises differentiating between efferent activity and afferent activity of the monitored electrical activity based on a direction of the monitored electrical activity, wherein the direction of the monitored electrical activity is determined based on at least one of polarity, timing, and velocity of the monitored electrical activity.

2. A method of delivering therapy, wherein the method comprises:

monitoring physiological parameters of a patient, wherein the physiological parameters comprise electrical activity of the patient'"'"'s vagus nerve;

determining whether the monitored electrical activity of the patient'"'"'s vagus nerve comprises efferent activity;

analyzing the monitored physiological parameters, wherein analyzing the monitored physiological parameters comprises determining whether the efferent activity of the electrical activity of the patient'"'"'s vagus nerve is reduced over time; and

initiating or adjusting non-nerve stimulating cardiac therapy if the efferent activity of the electrical activity of the patient'"'"'s vagus nerve is reduced, wherein the non-nerve stimulating cardiac therapy comprises at least one of pacing therapy, cardiac resynchronization therapy, anti-tachycardia pacing, high-energy shock pulses for cardioversion/defibrillation therapy, bradycardia pacing, and drug therapy, wherein determining whether the efferent activity of the electrical activity of the patient'"'"'s vagus nerve is reduced comprises comparing the average amplitude of a selected frequency range of the efferent activity to a selected value.

3. A method of delivering therapy, wherein the method comprises:

monitoring physiological parameters of a patient, wherein the physiological parameters comprise electrical activity of the patient'"'"'s vagus nerve;

determining whether the monitored electrical activity of the patient'"'"'s vagus nerve comprises efferent activity;

analyzing the monitored physiological parameters, wherein analyzing the monitored physiological parameters comprises determining whether the efferent activity of the electrical activity of the patient'"'"'s vagus nerve is reduced over time; and

initiating or adjusting non-nerve stimulating cardiac therapy if the efferent activity of the electrical activity of the patient'"'"'s vagus nerve is reduced, wherein the non-nerve stimulating cardiac therapy comprises at least one of pacing therapy, cardiac resynchronization therapy, anti-tachycardia pacing, high-energy shock pulses for cardioversion/defibrillation therapy, bradycardia pacing, and drug therapy, wherein determining whether the efferent activity of the electrical activity of the patient'"'"'s vagus nerve is reduced comprises comparing the average amplitude of a selected frequency range of the presently-monitored efferent activity to the average amplitude of the selected frequency range of previously-monitored efferent activity.

4. A method of delivering therapy, wherein the method comprises:

monitoring physiological parameters of a patient, wherein the physiological parameters comprise electrical activity of the patient'"'"'s vagus nerve;

determining whether the monitored electrical activity of the patient'"'"'s vagus nerve comprises efferent activity;

analyzing the monitored physiological parameters, wherein analyzing the monitored physiological parameters comprises determining whether the efferent activity of the electrical activity of the patient'"'"'s vagus nerve is reduced over time; and

initiating or adjusting non-nerve stimulating cardiac therapy if the efferent activity of the electrical activity of the patient'"'"'s vagus nerve is reduced, wherein the non-nerve stimulating cardiac therapy comprises at least one of pacing therapy, cardiac resynchronization therapy, anti-tachycardia pacing, high-energy shock pulses for cardioversion/defibrillation therapy, bradycardia pacing, and drug therapy, wherein determining whether the efferent activity of the electrical activity of the patient'"'"'s vagus nerve is reduced comprises comparing the average power of a selected frequency range of the efferent activity to a selected value.

5. A method of delivering therapy, wherein the method comprises:

monitoring physiological parameters of a patient, wherein the physiological parameters comprise electrical activity of the patient'"'"'s vagus nerve;

determining whether the monitored electrical activity of the patient'"'"'s vagus nerve comprises efferent activity;

analyzing the monitored physiological parameters, wherein analyzing the monitored physiological parameters comprises determining whether the efferent activity of the electrical activity of the patient'"'"'s vagus nerve is reduced over time; and

initiating or adjusting non-nerve stimulating cardiac therapy if the efferent activity of the electrical activity of the patient'"'"'s vagus nerve is reduced, wherein the non-nerve stimulating cardiac therapy comprises at least one of pacing therapy, cardiac resynchronization therapy, anti-tachycardia pacing, high-energy shock pulses for cardioversion/defibrillation therapy, bradycardia pacing, and drug therapy, wherein determining whether the efferent activity of the electrical activity of the patient'"'"'s vagus nerve is reduced comprises comparing the average power of a selected frequency range of the presently-monitored efferent activity to the average power of the selected frequency range of previously-monitored efferent activity.