Implantable neurostimulator-implemented method for managing tachyarrhythmia through vagus nerve stimulation

Abstract

An implantable neurostimulator-implemented method for managing tachyarrhythmias through vagus nerve stimulation is provided. An implantable neurostimulator, including a pulse generator, is configured to deliver electrical therapeutic stimulation in a manner that results in creation and propagation (in both afferent and efferent directions) of action potentials within neuronal fibers of a patient's cervical vagus nerve. Operating modes of the pulse generator are stored. A maintenance dose of the electrical therapeutic stimulation is delivered to the vagus nerve via the pulse generator to restore cardiac autonomic balance through continuously-cycling, intermittent and periodic electrical pulses. A restorative dose of the electrical therapeutic stimulation is delivered to prevent initiation of or disrupt tachyarrhythmia through periodic electrical pulses delivered at higher intensity than the maintenance dose. The patient's normative physiology is monitored via a physiological sensor, and upon sensing a condition indicative of tachyarrhythmia, is switched to delivering the restorative dose to the vagus nerve.

1 - 20 . (canceled) 
     
     
         21 . An implantable neurostimulator-implemented method for managing tachyarrhythmias through vagus nerve stimulation, comprising the steps of:
 providing an implantable neurostimulator comprising a pulse generator configured to deliver electrical stimulation to a vagus nerve of a patient;   storing an operating mode of the pulse generator in a recordable memory, the storing comprising:
 defining a maintenance dose of the electrical stimulation including determining a duty cycle for the maintenance dose using a function of targeted therapeutic efficacy and potential side effects; and 
 defining a restorative dose of the electrical stimulation, wherein the restorative dose comprises electrical pulses delivered at higher intensity than the maintenance dose; 
   delivering the maintenance dose at the duty cycle to the vagus nerve prior to delivering the restorative dose, prior to sensing a condition of tachyarrhythmia, and independent of cardiac cycle;   monitoring a patient's normative physiology to sense the condition of tachyarrhythmia via a physiological sensor of the implantable neurostimulator; and   upon sensing the condition of tachyarrhythmia, switching from delivering the maintenance dose to delivering the restorative dose to the vagus nerve.   
     
     
         22 . The method of  claim 21 , further comprising the step of:
 further defining the higher intensity of the restorative dose as comprising one or more of higher output current, higher frequency, or longer pulse width.   
     
     
         23 . The method of  claim 21 , further comprising the steps of:
 recording the patient's normative physiology in the recordable memory of the implantable neurostimulator;   determining a statistical average of the patient's recorded normative physiology via a controller of the implantable neurostimulator; and   defining the condition of the tachyarrhythmia as triggered when the statistical average exceeds a physiological threshold of arrhythmogenesis.   
     
     
         24 . The method of  claim 23 , further comprising the steps of:
 assigning more statistical weight to the patient's normative physiology which has been recorded recently;   assigning less statistical weight to the patient's normative physiology which has been recorded in the past; and   determining the statistical average as a weighted average of the patient's weighted normative physiology.   
     
     
         25 . The method of  claim 21 , further comprising the steps of:
 during the monitoring, confirming that the patient's normative physiology comprises a normal sinus rhythm; and   upon departure from the normal sinus rhythm, modifying the operating mode of the pulse generator based on whether the departure signifies an increase, decrease, or entrainment of cardiac rhythm.   
     
     
         26 . The method of  claim 25 , further comprising the steps of one of:
 intensifying the electrical stimulation as specified in the operating mode;   moderating the electrical stimulation as specified in the operating mode; and   suspending the electrical stimulation as specified in the operating mode.   
     
     
         27 . The method of  claim 21 , further comprising the steps of:
 constructing an endocardial electrogram based on the patient's normative physiology as sensed through the physiological sensor;   evaluating cardiac rate dynamics from the endocardial electrogram, including identifying R-waves; and   defining the condition of the tachyarrhythmia as triggered when the R-waves exhibit significant irregularity over a fixed time period.   
     
     
         28 . The method of  claim 21 , further comprising the step of:
 progressively increasing intensity of the electrical stimulation to the vagus nerve when delivering the restorative dose.   
     
     
         29 . The method of  claim 21 , further comprising the step of:
 progressively decreasing intensity of the electrical stimulation to the vagus nerve when resuming the delivery of the maintenance dose.   
     
     
         30 . The method of  claim 21 , further comprising the steps of:
 specifying one or more physiological markers of abnormally fast sinus rhythm as indicative of tachyarrhythmia;   monitoring the patient's sinus rhythm via the physiological sensor; and   upon sensing at least one physiological marker of abnormally fast sinus rhythm, triggering the delivery of the restorative dose.   
     
     
         31 . The method of  claim 30 , further comprising the steps of:
 specifying one or more physiological markers of normal sinus rhythm as a condition indicative of the absence of tachyarrhythmia; and   monitoring the patient's sinus rhythm via the physiological sensor during the delivery of the restorative dose for at least one physiological marker of normal sinus rhythm.   
     
     
         32 . The method of  claim 21 , further comprising the steps of:
 providing a leadless heart rate sensor configured as part of the pulse generator to sense the patient's heart rate in response to the electrical stimulation;   specifying a threshold heart rate as indicative of tachyarrhythmia;   monitoring the patient's heart rate through the leadless heart rate sensor; and   upon sensing of the patient's heart rate rising above the threshold heart rate, triggering the delivery of the restorative dose.   
     
     
         33 . The method of  claim 21 , wherein the maintenance dose has an intensity insufficient to elicit side effects. 
     
     
         34 . The method of  claim 21 , wherein determining the duty cycle for the maintenance dose is based on a quantitative expression of values of the targeted therapeutic efficacy and the potential side effects. 
     
     
         35 . The method of  claim 21 , wherein the duty cycle for the maintenance dose is determined using a function of an intersection of quantitatively expressed values of the targeted therapeutic efficacy and the potential side effects. 
     
     
         36 . An implantable neurostimulator for managing tachyarrhythmias through vagus nerve stimulation, comprising:
 a pulse generator configured to deliver electrical stimulation;   a processor configured to receive physiological data from a physiological sensor; and   a memory having instructions stored thereon that, when executed by the processor, cause the processor to:
 store an operating mode of the pulse generator in the memory by:
 defining a maintenance dose of the electrical stimulation including determining a duty cycle for the maintenance dose using a function of targeted therapeutic efficacy and potential side effects; and 
 defining a restorative dose of the electrical stimulation, wherein the restorative dose comprises electrical pulses delivered at higher intensity than the maintenance dose; 
 
 deliver the maintenance dose at the duty cycle to the vagus nerve prior to delivering the restorative dose, prior to sensing a condition of tachyarrhythmia, and independent of cardiac cycle; 
 monitor a patient's normative physiology to sense the condition of tachyarrhythmia via the physiological sensor; and 
 upon sensing the condition of tachyarrhythmia, switch from delivering the maintenance dose to delivering the restorative dose to the vagus nerve. 
   
     
     
         37 . The implantable neurostimulator of  claim 36 , wherein the duty cycle for the maintenance dose is further based on a quantitative expression of values of the targeted therapeutic efficacy and the potential side effects. 
     
     
         38 . The implantable neurostimulator of  claim 36 , wherein the duty cycle for the maintenance dose is further determined using a function of an intersection of quantitatively expressed values of the targeted therapeutic efficacy and the potential side effects. 
     
     
         39 . A non-transitory computer-readable medium comprising instructions executable by a processor of an implantable medical device to perform operations, the implantable medical device comprising a pulse generator and a physiological sensor, the operations comprising:
 storing an operating mode of the pulse generator in a recordable memory, the storing comprising:
 defining a maintenance dose of the electrical stimulation including determining a duty cycle for the maintenance dose using a function of targeted therapeutic efficacy and potential side effects; and 
 defining a restorative dose of the electrical stimulation, wherein the restorative dose comprises electrical pulses delivered at higher intensity than the maintenance dose; 
   delivering the maintenance dose at the duty cycle to the vagus nerve prior to delivering the restorative dose, prior to sensing a condition of tachyarrhythmia, and independent of cardiac cycle;   monitoring a patient's normative physiology to sense the condition of tachyarrhythmia via the physiological sensor; and   upon sensing the condition of tachyarrhythmia, switching from delivering the maintenance dose to delivering the restorative dose to the vagus nerve.   
     
     
         40 . The non-transitory computer-readable medium of  claim 39 , wherein determining the duty cycle for the maintenance dose is based on a quantitative expression of values of the targeted therapeutic efficacy and the potential side effects.