# US 11,077,304 B2 · Neurostimulation in a neural fulcrum zone for the treatment of chronic cardiac dysfunction > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,077,304 B2 - Document ID: US11077304B2 - Status: Granted - Kind: B2 - Application number: 16/422,588 - Filed: 2019-05-24 - Published: 2019-11-14 - Granted: 2021-08-03 - Earliest claimed: 2014-03-25 - Assignees: LivaNova USA, Inc.; East Tennessee State University - Applicants: LivaNova USA, Inc.; East Tennessee State University - Inventors: Bruce H. KenKnight; Jeffrey L. Ardell; Imad Libbus; Badri Amurthur - Web page: https://patentgrep.com/patent/US11077304B2 ## CPC - A61N 1/36139: {with automatic adjustment} - A61N 1/36053: {adapted for vagal stimulation (A61N1/36114 takes precedence)} - A61N 1/36114: {Cardiac control, e.g. by vagal stimulation (stimulating the heart A61N1/362)} - A61N 1/3615: {Intensity} - A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B) ## Abstract Systems and methods are provided for delivering neurostimulation therapies to patients for treating chronic heart failure. A neural fulcrum zone is identified and ongoing neurostimulation therapy is delivered within the neural fulcrum zone. This neural fulcrum zone corresponds to a combination of stimulation parameters at which autonomic engagement is achieved, while the tachycardia-inducing stimulation effects are offset by the bradycardia-inducing effects, thereby minimizing side effects such as significant heart rate changes while providing a therapeutic level of stimulation. ## Claims ### Claim 1 A method of operating an implantable medical device (IMD), the method comprising: generating a plurality of stimulation signals configured to stimulate a nerve of a patient, each stimulation signal of the plurality of stimulation signals having a frequency, an amplitude, and a pulse width, wherein generating the plurality of stimulation signals comprises adjusting at least one of the amplitude or the pulse width while maintaining a fixed frequency across the plurality of stimulation signals; detecting a heart rate response of the patient during the generation of the plurality of stimulation signals; identifying a range of the adjusted at least one pulse width or amplitude that results in the heart rate response being between a baseline heart rate and a heart rate decrease threshold; and delivering a plurality of stimulation signals at a frequency, amplitude, and pulse width resulting in the heart rate response being between the baseline heart rate and the heart rate decrease threshold. ### Claim 2 (depends on 1) The method of claim 1, wherein the fixed frequency is selected from 2 Hz to 20 Hz. ### Claim 3 (depends on 2) The method of claim 2, wherein the fixed frequency is 5 Hz. ### Claim 4 (depends on 1) The method of claim 1, wherein the amplitude is adjusted between at least a subset of 0 mA to 3.5 mA. ### Claim 5 (depends on 1) The method of claim 1, wherein the amplitude is adjusted while maintaining a fixed pulse width and the fixed frequency. ### Claim 6 (depends on 5) The method of claim 5, wherein the fixed pulse width is 250 μs. ### Claim 7 (depends on 1) The method of claim 1, wherein generating the plurality of stimulation signals further comprises generating stimulation signals having the fixed frequency, an amplitude of 1.0 mA, and a pulse width of 250 μs and increasing the at least one of the amplitude or pulse width while maintaining the fixed frequency. ### Claim 8 (depends on 7) The method of claim 7, wherein the fixed frequency is selected from 2 Hz to 20 Hz. ### Claim 9 (depends on 8) The method of claim 8, wherein the fixed frequency is 5 Hz. ### Claim 10 (depends on 1) The method of claim 1, further comprising: increasing the at least one of the pulse width or amplitude in response to detecting a tachycardia condition, wherein the tachycardia condition is defined by a heart rate increase above the baseline heart rate; and decreasing the at least one of the pulse width or amplitude in response to detecting a bradycardia condition, wherein the bradycardia condition is defined by a heart rate decrease below the heart rate decrease threshold. ### Claim 11 An implantable medical device (IMD), comprising: a neurostimulator configured to deliver a stimulation signal to a nerve of a patient; and a control system programmed to: generate a plurality of stimulation signals configured to stimulate a nerve of a patient, each stimulation signal of the plurality of stimulation signals having a frequency, an amplitude, and a pulse width, wherein control system is programmed to generate the plurality of stimulation signals by adjusting at least one of the amplitude or the pulse width while maintaining a fixed frequency across the plurality of stimulation signals; detect a heart rate response of the patient during the generation of the plurality of stimulation signals; identify a range of the adjusted at least one pulse width or amplitude that results in the heart rate response being between a baseline heart rate and a heart rate decrease threshold; and deliver a plurality of stimulation signals at a frequency, amplitude, and pulse width resulting in the heart rate response being between the baseline heart rate and the heart rate decrease threshold. ### Claim 12 (depends on 11) The IMD of claim 11, wherein the fixed frequency is selected from 2 Hz to 20 Hz. ### Claim 13 (depends on 12) The IMD of claim 12, wherein the fixed frequency is 5 Hz. ### Claim 14 (depends on 11) The IMD of claim 11, wherein the amplitude is adjusted between at least a subset of 0 mA to 3.5 mA. ### Claim 15 (depends on 11) The IMD of claim 11, wherein the control system is configured to adjust the amplitude while maintaining a fixed pulse width and the fixed frequency. ### Claim 16 (depends on 15) The IMD of claim 15, wherein the fixed pulse width is 250 μs. ### Claim 17 (depends on 11) The IMD of claim 11, wherein the control system is further configured to generate the plurality of stimulation signals by generating stimulation signals having the fixed frequency, an amplitude of 1.0 mA, and a pulse width of 250 μs and increasing the at least one of the amplitude or pulse width while maintaining the fixed frequency. ### Claim 18 (depends on 17) The IMD of claim 17, wherein the fixed frequency is selected from 2 Hz to 20 Hz. ### Claim 19 (depends on 18) The IMD of claim 18, wherein the fixed frequency is 5 Hz. ### Claim 20 (depends on 11) The IMD of claim 11, wherein the control system is further configured to: increase the at least one of the pulse width or amplitude in response to detecting a tachycardia condition, wherein the tachycardia condition is defined by a heart rate increase above the baseline heart rate; and decrease the at least one of the pulse width or amplitude in response to detecting a bradycardia condition, wherein the bradycardia condition is defined by a heart rate decrease below the heart rate decrease threshold.