Stimulus regimens for cardiovascular reflex control

Abstract

Baroreflex activation is achieved by providing suitable control signals to a baroreflex activation device. A method comprises establishing a therapy interval within the therapy interval, establishing a plurality of dose intervals, and generating an electrical output signal. The electrical output signal has a time dependence such that the average electrical power applied to the baroreflex activation device differs between first and second portions of at least some dose intervals. Another method comprises establishing a series of therapy interval portions, during at least some therapy intervals, establishing a plurality of burst intervals, and generating an electrical output signal. The electrical output signal has a time dependence such that the average electrical power applied to the baroreflex activation device differs between first and second portions of the therapy intervals and also differs between first and second portions of at least some burst intervals.

1 . A method of operating an implantable pulse generator, the pulse generator programmed to include multiple modes of operation for stimulating a baroreceptor of a patient as part of a baroreflex therapy, the method comprising:
 applying electrical power from the implantable pulse generator to the baroreceptor according to a programmed mode of operation to achieve a desired physiological response;   automatically monitoring an energy level of a battery associated with the pulse generator; and   automatically changing the mode of operation of the pulse generator to a different mode of operation to reduce an output of electrical power of the pulse generator while maintaining the desired physiological response in response to the energy level of the battery falling below a threshold level.   
     
     
         2 . The method of  claim 1 , further comprising automatically monitoring a physiological response to the changing the mode of operation of the pulse generator. 
     
     
         3 . The method of  claim 1 , wherein automatically monitoring an energy level of the battery comprises automatically monitoring the voltage of the battery. 
     
     
         4 . The method of  claim 1 , wherein automatically monitoring an energy level of the battery comprises automatically monitoring the current drain of the battery. 
     
     
         5 . The method of  claim 1 , wherein automatically monitoring the energy level of the battery includes interpreting a signal representative of the energy level of the battery. 
     
     
         6 . The method of  claim 5 , wherein the signal representative of the energy level of the battery instructs the changing of the mode of operation when the battery energy falls below the threshold energy. 
     
     
         7 . The method of  claim 1 , wherein a mode of operation comprises a dose regimen, and wherein changing the mode of operation of the pulse generator to a different mode of operation comprises changing the dose regimen. 
     
     
         8 . An implantable pulse generator, comprising:
 a source of electrical energy for applying electrical power to a baroreceptor to achieve a desired physiological response as part of a baroreflex therapy administered to a patient;   an energy monitor that monitors an energy level of the implantable pulse generator; and   means for changing operation of the implantable pulse generator to adjust an output of electrical power of the implantable pulse generator while maintaining the desired physiological response.   
     
     
         9 . The pulse generator of  claim 8 , wherein the energy monitor is configured to monitor the voltage of the implantable pulse generator. 
     
     
         10 . The pulse generator of  claim 8 , wherein the energy monitor is configured to monitor the current drain of the implantable pulse generator. 
     
     
         11 . The pulse generator of  claim 8 , wherein the implantable pulse generator is configured to change the output of electrical power to reduce energy consumption of the implantable pulse generator while maintaining the desired physiological response. 
     
     
         12 . The method of  claim 8 , wherein the means for changing operation further comprises changing one or more pulse characteristics of therapy pulses generated by the implantable pulse generator as part of the operation. 
     
     
         13 . The method of  claim 12 , wherein the pulse characteristics are selected from the group consisting of: duty cycle, pulse amplitude, pulse width, pulse frequency, pulse separation, pulse waveform, pulse polarity, and pulse phase. 
     
     
         14 . An implantable pulse generator for stimulating a baroreflex system of a patient, comprising:
 a battery for providing electrical energy for use by the implantable pulse generator;   a detector that detects an energy level of the battery; and   circuitry that generates and delivers stimulation pulses as part of a baroreflex therapy administered to the patient, the pulse generator programmed to include multiple modes of operation for delivery of the stimulation pulses, wherein the modes are responsive to the energy level of the battery,   the implantable pulse generator further programmed to change mode of operation at least once to a mode requiring a lower electrical consumption of the battery when the energy level of the battery falls below a threshold energy level.   
     
     
         15 . The implantable pulse generator of  claim 14 , further including:
 a memory system in communication with the processor and the battery, the memory system configured to store information regarding the multiple modes of operation, wherein at least one mode of operation requires a lower power consumption than at least one other mode of operation.   
     
     
         16 . The implantable pulse generator of  claim 15 , further including a processor that controls the mode of operation, wherein the mode of operation is at least once changed to lower electrical consumption of the battery when the battery energy falls below the threshold energy. 
     
     
         17 . The implantable pulse generator of  claim 14 , wherein the implantable pulse generator is connectable to a baroreflex activation device implantable proximate a baroreceptor of the patient, the baroreflex activation device configured for delivery of stimulation pulses from the implantable pulse generator to the baroreceptor. 
     
     
         18 . The implantable pulse generator of  claim 14 , wherein the implantable pulse generator is further programmed to one or more characteristics of therapy pulses generated by the implantable pulse generator as part of changing a mode of operation of the implantable pulse generator. 
     
     
         19 . The method of  claim 18 , wherein the pulse characteristic are selected from the group consisting of: duty cycle, pulse amplitude, pulse width, pulse frequency, pulse separation, pulse waveform, pulse polarity, and pulse phase. 
     
     
         20 . A method of controlling an implantable pulse generator for baroreflex activation, comprising:
 causing an implantable pulse generator to be manufactured and made available to a user; and   providing instructions to the user, the instructions comprising:
 applying electrical power from an implantable pulse generator to a baroreceptor to achieve a desired physiological response as part of a baroreflex therapy administered to a patient; 
 monitoring an energy level of the implantable pulse generator; and 
 changing operation of the implantable pulse generator to adjust an output of electrical power of the pulse generator, while maintaining the desired physiological response.