Neurostimulation titration utilizing T-wave alternans
Systems and methods are provided for delivering neurostimulation therapies to patients. A titration process is used to gradually increase the stimulation intensity to a desired therapeutic level until a target T-wave alternans change from a baseline T-wave alternans is achieved.
1. A method of operating an implantable medical device (IMD) comprising a neurostimulator coupled to an electrode assembly, said neurostimulator adapted to deliver a stimulation signal to a patient, said method comprising:
computationally determining a current cardiac magnitude value for the patient, wherein the cardiac magnitude value comprises a T-wave alternans (TWA) magnitude value;
activating the IMD to deliver to the patient a plurality of stimulation signals at increasing stimulation intensities until the current cardiac magnitude value reaches a target cardiac magnitude; and
activating the IMD to deliver a therapeutic level of stimulation corresponding to the stimulation intensity in response to which the current cardiac magnitude value reached the target cardiac magnitude.
2. The method of claim 1 , wherein computationally determining the cardiac magnitude value for the patient is performed by the IMD.
3. The method of claim 1 , wherein the target cardiac magnitude is a target TWA magnitude comprising approximately 47 μV.
4. The method of claim 1 , further comprising determining a baseline cardiac magnitude value for the patient;
wherein the target cardiac magnitude comprises a target change in the current cardiac magnitude from the baseline cardiac magnitude.
5. The method of claim 4 , wherein the target change is a target TWA change comprising approximately 10 μV.
6. The method of claim 4 , further comprising identifying a neural fulcrum zone corresponding to the stimulation intensity in response to which the target change from the baseline was observed.
7. The method of claim 4 , further comprising performing a baseline update process, the baseline update process comprising:
temporarily ceasing the delivery of the stimulation to the patient;
monitoring an ECG of the patient to determine an updated baseline for the patient;
activating the IMD to deliver to the patient a plurality of stimulation signals at increasing stimulation intensities until the target change from the updated baseline is observed; and
activating the IMD to deliver a therapeutic level of stimulation corresponding to the stimulation intensity in response to which the target change from the updated baseline was observed.
8. A neurostimulation system, comprising:
an implantable medical device (IMD) comprising:
an electrode assembly;
a neurostimulator coupled to the electrode assembly, wherein the neurostimulator is adapted to deliver a stimulation signal to a patient; and
a control system programmed to:
computationally determine a current cardiac magnitude value for the patient, wherein the cardiac magnitude value comprises a T-wave alternans (TWA) magnitude value;
activate the IMD to deliver to the patient a plurality of stimulation signals at increasing stimulation intensities until the current cardiac magnitude value reaches a target cardiac magnitude; and
activate the IMD to deliver a therapeutic level of stimulation corresponding to the stimulation intensity in response to which the current cardiac magnitude value reached the target cardiac magnitude.
9. The neurostimulation system of claim 8 , wherein the target cardiac magnitude is a target TWA magnitude comprising approximately 47 μV.
10. The neurostimulation system of claim 8 , wherein the control system is further programmed to determine a baseline cardiac magnitude value for the patient;
wherein the target cardiac magnitude comprises a target change in the current cardiac magnitude from the baseline cardiac magnitude.
11. The neurostimulation system of claim 10 , wherein the target change is a target TWA change comprising approximately 10 μV.
12. The neurostimulation system of claim 10 , wherein the control system is further programmed to identify a neural fulcrum zone corresponding to the stimulation intensity in response to which the target change from the baseline was observed.
13. The neurostimulation system of claim 10 , wherein the control system is further programmed to perform a baseline update process, the baseline update process comprising:
temporarily ceasing the delivery of the stimulation to the patient;
monitoring an ECG of the patient to determine an updated baseline for the patient;
activating the IMD to deliver to the patient a plurality of stimulation signals at increasing stimulation intensities until the target change from the updated baseline is observed; and
activating the IMD to deliver a therapeutic level of stimulation corresponding to the stimulation intensity in response to which the target change from the updated baseline was observed.
14. A neurostimulation system, comprising:
an implantable medical device (IMD) comprising:
an electrode assembly;
a neurostimulator coupled to the electrode assembly, wherein the neurostimulator is adapted to deliver a stimulation signal to a patient;
an electrodcardiogram (ECG) sensor; and
a control system programmed to:
activate the IMD to deliver to the patient a plurality of stimulation signals;
monitor the ECG of the patient using the ECG sensor; and
determine a cardiac value based on the monitored ECG, wherein the cardiac value comprises a T-wave alternans (TWA) value.
15. The neurostimulation system of claim 14 , wherein the control system is further programmed to determine a cardiac value baseline for the patient.
16. The neurostimulation system of claim 15 , wherein the control system is further programmed to determine whether a target change from the cardiac value baseline has occurred in response to the delivery of the plurality of stimulation signals.
17. The neurostimulation system of claim 16 , wherein the control system is further programmed to, in response to determining that the target change has occurred, activate the IMD to deliver to the patient therapeutic stimulation at a level causing the target change from the cardiac value baseline.
18. The neurostimulation system of claim 16 , wherein the control system is further programmed to, in response to determining that the target change has occurred, identify a neural fulcrum zone corresponding to a stimulation intensity causing the target change from the cardiac value baseline.