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

• US 9,919,157 B2
• Filed: 02/11/2014
• Issued: 03/20/2018
• Est. Priority Date: 07/20/2012
• Status: Active Grant

• Current Assignee: LivaNova USA, Inc. (LivaNova Plc)
• Original Assignee: Cyberonics, Inc
• Inventors: Libbus, Imad, Amurthur, Badri, KenKnight, Bruce H.
• Primary Examiner(s): Patel, Niketa
• Assistant Examiner(s): PHAM, MINH DUC GIA
• Application Number:
  US14/177,542
• Publication Number:
  US 20140155949A1
• Time in Patent Office: 1,498 Days
• Field of Search: 607 17
• CPC Class Codes: A61B 5/363 Detecting tachycardia or bradycardia
• 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 1/36167 Timing, e.g. stimulation onset
• CPC Class Codes: A61N 1/36171 Frequency
• CPC Class Codes: A61N 1/36175 Pulse width or duty cycle
• CPC Class Codes: A61N 1/365 controlled by a physiological parameter, e.g. heart potential evoked response A61N1/371

Abstract

A method for managing bradycardia through vagus nerve stimulation is provided. An implantable neurostimulator configured to deliver electrical therapeutic stimulation in both afferent and efferent directions of a patient'"'"'s cervical vagus nerve is provided. An operating mode is stored, which includes parametrically defining a maintenance dose of the electrical therapeutic stimulation tuned to restore cardiac autonomic balance through continuously-cycling, intermittent and periodic electrical pulses. The maintenance dose is delivered via a pulse generator through a pair of helical electrodes via an electrically coupled nerve stimulation therapy lead independent of cardiac cycle. The patient'"'"'s physiology is monitored, and upon sensing a condition indicative of bradycardia, the delivery of the maintenance dose is suspended. A progressively increasing amount of time is spent waiting via a controller and, upon sensing a condition indicative of an absence or termination of the bradycardia, a progressively increasing partial maintenance dose is delivered via the pulse generator.

Claims

1. A method for managing bradycardia through vagus nerve stimulation, comprising the steps of:

defining a maintenance dose of electrical therapeutic stimulation;

delivering the maintenance dose to a vagus nerve of a patient independent of cardiac cycle;

periodically monitoring the patient'"'"'s physiology via a physiological sensor;

upon sensing a condition indicative of bradycardia, suspending the delivery of the maintenance dose to the vagus nerve, comprising;

determining a back-off delay comprising an amount of time that increases over each previous back-off delay;

upon expiry of the back-off delay, checking the patient'"'"'s physiology via the physiological sensor; and

upon sensing a condition indicative of an absence or termination of the bradycardia, delivering the maintenance dose at a partial duty cycle to the vagus nerve;

resuming the periodic monitoring of the patient'"'"'s physiology; and

upon sensing a condition indicative of a continued absence of bradycardia, gradually increasing the duty cycle of the maintenance dose in response to the periodic monitoring of the patient'"'"'s physiology.

2. A method according to claim 1, further comprising the steps of:

upon sensing a condition indicative of a recurrence of the bradycardia, re-suspending the delivery of the maintenance dose to the vagus nerve, comprising;

exponentially increasing the back-off delay over a back-off delay most recently used during suspension of the delivery of the maintenance dose to the vagus nerve; and

upon expiry of the increasing back-off delay, checking the patient'"'"'s physiology via the physiological sensor.

3. A method according to claim 2, further comprising the steps of:

continuing the re-suspension of the delivery of the maintenance dose; and

terminating the delivery of the maintenance dose to the vagus nerve once a maximum back-off delay has been reached.

4. A method according to claim 1, further comprising the step of:

sensing the condition indicative of bradycardia based on at least one of abnormal sinus rhythm and heart rate falling below a minimum threshold.

5. A non-transitory computer readable storage medium storing code for executing on a computer system to perform the method according to claim 1.

6. A method according to claim 1, wherein the pulsed electrical signals propagate in both an efferent and efferent direction.

7. A method for managing bradycardia through vagus nerve stimulation, comprising the steps of:

defining a maintenance dose of electrical therapeutic stimulation, wherein the electrical therapeutic stimulation comprises a pulsed electrical signal comprising;

a signal ON time;

a signal OFF time;

an output current;

a signal frequency of approximately 10 Hz;

a pulse width; and

a duty cycle defined by dividing the signal ON time by the sum of the signal ON time and signal OFF time;

delivering the maintenance dose to a vagus nerve of a patient independent of cardiac cycle;

periodically monitoring the patient'"'"'s physiology via a physiological sensor;

upon sensing a condition indicative of bradycardia, suspending the delivery of the maintenance dose to the vagus nerve, comprising;

determining a back-off delay comprising an amount of time that increases over each previous back-off delay;

upon expiry of the back-off delay, checking the patient'"'"'s physiology via the physiological sensor; and

upon sensing a condition indicative of an absence or termination of the bradycardia, delivering the maintenance dose at a partial duty cycle to the vagus nerve;

resuming the periodic monitoring of the patient'"'"'s physiology; and

upon sensing a condition indicative of a continued absence of bradycardia, gradually increasing the duty cycle of the maintenance dose in response to the periodic monitoring of the patient'"'"'s physiology.

8. A method according to claim 7, further comprising the steps of:

upon sensing a condition indicative of a recurrence of the bradycardia, re-suspending the delivery of the maintenance dose to the vagus nerve, comprising;

exponentially increasing the back-off delay over a back-off delay most recently used during suspension of the delivery of the maintenance dose to the vagus nerve; and

upon expiry of the increased back-off delay, checking the patient'"'"'s physiology via the physiological sensor.

9. A method according to claim 8, further comprising the steps of:

continuing the re-suspension of the delivery of the maintenance dose; and

terminating the delivery of the maintenance dose to the vagus nerve once a maximum back-off delay has been reached.

10. A method according to claim 7, further comprising the step of:

sensing the condition indicative of bradycardia based on at least one of abnormal sinus rhythm and heart rate falling below a minimum threshold.

11. A non-transitory computer readable storage medium storing code for executing on a computer system to perform the method according to claim 7.

12. A method according to claim 7, wherein the pulsed electrical signal further comprises a signal ramp-down time.

13. A method according to claim 7, wherein the pulsed electrical signal further comprises a signal ramp-up time.

14. A method according to claim 7, wherein the pulsed electrical signals propagate in both an efferent and efferent direction.

15. A method according to claim 7, wherein the duty cycle is in a range of 4% to 36%.