Stimulus regimens for cardiovascular reflex control
Devices, systems and methods by which the blood pressure, nervous system activity, and neurohormonal activity may be selectively and controllably reduced by activating baroreceptors. A baroreceptor activation device is positioned near a baroreceptor, for example a baroreceptor in the carotid sinus. A control system may be used to modulate the baroreceptor activation device. The control system may utilize an algorithm defining a stimulus regimen which promotes long term efficacy and reduces power requirements/consumption.
1. A method of inducing a change in the baroreflex system of a patient, the method comprising the steps of:
providing an activation device;
positioning the activation device proximate a baroreceptor in a vascular wall so as to preferentially induce a physiologic change in the baroreceptor; and
automatically controlling an output of the activation device to induce the change in the baroreflex system, the output including a first level delivered for a first period of time to attain the physiologic change and a second level delivered for a second period of time to retain the physiologic change, wherein the first level attains the physiologic change more quickly than the second level and the second level is different than the first level over time so as to promote long term efficacy in inducing the change in the baroreflex system.
2. A method as in claim 1 , wherein the second level is delivered independently of feedback from a sensor.
3. A method as in claim 1 , wherein the activation device mechanically, electrically, thermally, chemically or biologically induces the change in the baroreflex system.
4. A method as in claim 3 , wherein the output of the activation device comprises an electrical signal, and wherein the electrical signal induces the change in the baroreflex system.
5. A method as in claim 4 , wherein the electrical output signal has an amplitude, and wherein the amplitude of the first level is different than the amplitude of the second level.
6. A method as in claim 4 , wherein the electrical output signal comprises a series of pulses having a pulse frequency, and wherein the pulse frequency of the first level is different than the pulse frequency of the second level.
7. A method as in claim 4 , wherein the electrical output signal has a pulse width, and wherein the pulse width of the first level is different than the pulse width of the second level.
8. A method of claim 4 , wherein the electrical output signal comprises a series of pulses delivered in bursts having a burst frequency, and wherein the burst frequency of the first level is greater than the burst frequency of the second level.
9. A method as in claim 1 , wherein the change in the baroreflex system comprises inducing a baroreceptor signal.
10. A method as in claim 4 , wherein the electrical output signal comprises a series of pulses, each pulse having an amplitude, and wherein the amplitude of each pulse of the first level is different than the amplitude of each pulse of the second level.
11. A method as in claim 4 , wherein the electrical output signal comprises a series of pulses, each pulse having a pulse width, and wherein the pulse width of each pulse of the first level is different than the pulse width of each pulse of the second level.