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

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%.