Controlled titration of neurostimulation therapy
Described herein are methods and devices that utilize electrical neural stimulation to treat heart failure by modulating a patient's autonomic balance in a manner that inhibits sympathetic activity and/or augments parasympathetic activity. Because other therapies for treating heart failure may also affect a patient's autonomic balance, a device for delivering neural stimulation is configured to appropriately titrate such therapy in either an open-loop or closed-loop fashion.
1. An implantable device for delivering neurostimulation, comprising:
a pulse generator for outputting neural stimulation pulses;
one or more stimulation electrodes connected to the pulse generator for delivering electrical stimulation to a selected neural site;
a controller connected to the pulse generator for controlling the output of neural stimulation pulses in accordance with a defined schedule that schedules delivery of neural stimulation in accordance with a patient's circadian rhythms and in accordance with specified stimulation parameters;
a telemetry unit interfaced to the controller for enabling user input of a defined schedule for delivering neurostimulation and specified stimulation parameters; and,
wherein the controller is programmed to receive medication dosage information via telemetry and modify the schedule for delivering neurostimulation accordingly.
2. The device of claim 1 wherein the controller is further programmed to modify the stimulation parameters in accordance with the medication dosage information.
3. The device of claim 1 wherein the stimulation electrodes are configurable for delivering stimulation to the vagus nerve or a baroreceptor of a patient and wherein the controller is programmed to reduce the amount of neurostimulation delivered when the patient takes a dose of a beta-blocker.
4. The device of claim 1 wherein the stimulation electrodes are configurable for delivering stimulation to the vagus nerve or a baroreceptor of a patient and wherein the controller is programmed to increase the amount of neurostimulation delivered when the patient takes a dose of a diuretic.
5. The device of claim 1 wherein the controller is programmed to receive medication dosage information from an electronic pill counter.
6. A method, comprising:
programming an implantable device to deliver neural stimulation pulses to a selected neural site in accordance with a defined schedule that schedules delivery of neural stimulation in accordance with the patient's circadian rhythms and in accordance with specified stimulation parameters; and,
programming the implantable device to receive medication dosage information via telemetry and modify the schedule for delivering neurostimulation accordingly.
7. The method of claim 6 further comprising programming the implantable device to modify the stimulation parameters in accordance with the medication dosage information.
8. The method of claim 6 wherein the selected neural site is the vagus nerve or a baroreceptor of a patient and further comprising programming the implantable device to reduce the amount of neurostimulation delivered when the patient takes a dose of a beta-blocker.
9. The method of claim 6 wherein the selected neural site is the vagus nerve or a baroreceptor of a patient and further comprising programming the implantable device to increase the amount of neurostimulation delivered when the patient takes a dose of a diuretic.
10. The method of claim 6 further comprising programming the implantable device to receive medication dosage information from an electronic pill counter.
11. The method of claim 6 further comprising:
programming the implantable device to sense a physiological variable reflective of a patient's autonomic balance; and,
programming the implantable device to adjust the amount of neurostimulation delivered in accordance with a determination of the patient's autonomic balance.
12. The method of claim 6 further comprising programming the implantable device to adjust the amount of neurostimulation delivered in accordance with the patient's measured heart rate.
13. The method of claim 6 further comprising programming the implantable device to:
measure and collect time intervals between successive intrinsic beats, referred to as a BB interval, and storing the collected intervals as a discrete BB interval signal, filter the BB interval signal into defined high and low frequency bands, and determine the signal power of the BB interval signal in each of the low and high frequency bands, referred to LF and HF, respectively; and,
compute an LF/HF ratio and assess autonomic balance by comparing the LF/HF ratio to a specified threshold value; and,
adjust the amount of neurostimulation delivered in accordance with the patient's autonomic balance.
14. The method of claim 13 further comprising programming the implantable device to assess autonomic balance in accordance with a measured activity level.