# US 10,765,870 B2 · Method and apparatus for detection of intrinsic depolarization following high energy cardiac electrical stimulation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,765,870 B2 - Document ID: US10765870B2 - Status: Granted - Kind: B2 - Application number: 16/196,320 - Filed: 2018-11-20 - Published: 2019-03-21 - Granted: 2020-09-08 - Earliest claimed: 2015-04-23 - Assignees: Medtronic, Inc. - Applicants: Medtronic, Inc. - Inventors: Saul E. Greenhut; Michael T. Hemming - Web page: https://patentgrep.com/patent/US10765870B2 ## CPC - A61B 5/287: Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS] - A61B 5/349: Detecting specific parameters of the electrocardiograph cycle - A61B 5/363: Detecting tachycardia or bradycardia - A61B 5/686: {Permanently implanted devices, e.g. pacemakers, other stimulators, biochips (A61B5/6861 takes precedence)} - A61N 1/3621: {for treating or preventing abnormally high heart rate} - A61N 1/3622: {comprising two or more electrodes co-operating with different heart regions} - A61N 1/3625: {External stimulators} - A61N 1/3702: {Physiological parameters (A61N1/365 takes precedence; evoked response A61N1/371)} - A61N 1/371: {Capture, i.e. successful stimulation} - A61N 1/3925: {Monitoring; Protecting} - A61N 1/3956: {Implantable devices for applying electric shocks to the heart, e.g. for cardioversion} - A61N 1/3962: {in combination with another heart therapy} - A61N 1/39622: {Pacing therapy} - A61B 5/021: Measuring pressure in heart or blood vessels - A61B 5/1118: {Determining activity level} - A61B 5/282: Holders for multiple electrodes (for introduction into the body A61B5/287) - A61B 5/352: Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval - G06F 2218/10: by analysing the shape of a waveform, e.g. extracting parameters relating to peaks - G06F 2218/14: by matching peak patterns - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - 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) - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract A medical device is configured to deliver a high-energy electrical stimulation pulse to a patient that produces a post-stimulation polarization signal. A cardiac signal analyzer of the medical device is configured to detect a cardiac electrical signal superimposed on the post-stimulation polarization signal, determine at least one feature of the detected cardiac electrical signal, compare the feature to criteria that differentiate an intrinsic cardiac event during the post-stimulation polarization signal from an evoked response signal and identify the detected cardiac electrical signal as the intrinsic cardiac event if the feature meets the criteria. ## Claims ### Claim 1 A method comprising: delivering a first electrical stimulation pulse to a patient that produces a post-stimulation polarization signal; starting a pacing escape interval upon delivering the electrical stimulation pulse; setting a blanking interval upon delivering the electrical stimulation pulse, the blanking interval extending beyond a time of an expected evoked response signal caused by the electrical stimulation pulse; obtaining, after the blanking interval expires, an electrical signal sensed on an electrode vector, the electrical signal including a cardiac electrical signal superimposed on the post-stimulation polarization signal; determining a feature of the sensed electrical signal; comparing the feature of the sensed electrical signal to criteria for identifying an intrinsic cardiac event during the post-stimulation polarization signal; identifying the intrinsic cardiac event when the feature meets the criteria; restarting the pacing escape interval in response to identifying the intrinsic cardiac event; and delivering a second electrical stimulation pulse in response to expiration of the pacing escape interval. ### Claim 2 (depends on 1) The method of claim 1, wherein: determining the feature of the sensed electrical signal comprises determining a slope of the sensed electrical signal; and wherein identifying the intrinsic cardiac event when the feature meets the criteria comprises identifying the intrinsic cardiac event when an acceleration of a decaying slope of the electrical signal is detected. ### Claim 3 (depends on 1) The method of claim 1, wherein: determining the feature of the sensed electrical signal comprises determining a slope of the sensed electrical signal; and wherein identifying the intrinsic cardiac event when the feature meets the criteria comprises identifying the intrinsic cardiac event when a change in a polarity of the decaying slope of the post-stimulation polarization signal is detected. ### Claim 4 (depends on 1) The method of claim 1, wherein: determining the feature comprises determining if the sensed electrical signal is at least a biphasic signal having at least one positive-going peak relative to a decaying portion of the polarization signal and at least one negative-going peak relative to the decaying portion of the polarization signal; identifying the intrinsic cardiac event comprises identifying the detected cardiac electrical signal as the intrinsic cardiac event when it is determined that the cardiac electrical signal is at least a biphasic signal. ### Claim 5 (depends on 1) The method of claim 1, wherein: determining the feature comprises determining at least one of a signal width and a signal area of the detected cardiac electrical signal; comparing the feature to the criteria comprises comparing at least one of the signal width and the signal area to a respective signal width threshold and a signal area threshold; and identifying the intrinsic cardiac event comprises identifying the intrinsic cardiac event when it is determined that at least one of the signal width and the signal area is less than the signal width threshold and the signal area threshold respectively. ### Claim 6 (depends on 1) The method of claim 1, further comprising: establishing an intrinsic event waveform template; wherein determining the feature of the sensed electrical signal comprises determining a waveform morphology of the sensed electrical signal; wherein comparing the feature to the criteria comprises determining a correlation between the waveform morphology and the template and comparing the correlation to a threshold; wherein identifying the intrinsic cardiac event comprises identifying the intrinsic cardiac event when it is determined that the correlation is greater than the threshold. ### Claim 7 (depends on 1) The method of claim 1, further comprising: disabling a cardiac event sensing module during the post-stimulation polarization signal; and enabling a cardiac signal analyzer during the post-stimulation polarization signal to detect the sensed electrical signal and identify the intrinsic cardiac event. ### Claim 8 (depends on 1) The method of claim 1, wherein delivering the electrical stimulation pulse comprises delivering the electrical stimulation pulse as one of a cardioversion/defibrillation shock pulse and an extracardiac pacing pulse having a pacing pulse energy greater than 1 milliJoule. ### Claim 9 A medical device comprising: a therapy delivery module configured to deliver a first electrical stimulation pulse to a patient that produces a post-stimulation polarization signal; a control module configured to start a pacing escape interval upon delivery of the electrical stimulation pulse; and a cardiac signal analyzer configured to: set a blanking interval upon delivery of the electrical stimulation pulse, the blanking interval extending beyond a time of an expected evoked response signal caused by the electrical stimulation pulse; obtain an electrical signal sensed across a pair of electrodes coupled to the medical device; determine a feature of the sensed electrical signal; compare the feature of the sensed electrical signal to criteria for identifying an intrinsic cardiac event during the post-stimulation polarization signal; identify the intrinsic cardiac event if the feature meets the criteria; wherein the control module is configured to restart the pacing escape interval in response to identifying the intrinsic cardiac event, and wherein the therapy delivery module is configured to deliver a second electrical stimulation pulse in response to expiration of the pacing escape interval. ### Claim 10 (depends on 9) The device of claim 9, wherein the cardiac signal analyzer is configured to determine the feature by determining a slope of the sensed electrical signal and identify the intrinsic cardiac event when an acceleration of a decaying slope of the electrical signal is detected. ### Claim 11 (depends on 9) The device of claim 9, wherein the cardiac signal analyzer is configured to determine the feature by determining a slope of the sensed electrical signal and identify the intrinsic cardiac event when a change in a polarity of the decaying slope of the post-stimulation polarization signal is detected. ### Claim 12 (depends on 9) The device of claim 9, wherein the cardiac signal analyzer is further configured to: determine the feature by determining if the sensed electrical signal is at least a biphasic signal having at least one positive-going peak relative to a decaying portion of the polarization signal and at least one negative-going peak relative to the decaying portion of the polarization signal; identify intrinsic cardiac event when the sensed electrical signal is determined to be at least a biphasic signal. ### Claim 13 (depends on 9) The device of claim 9, wherein the cardiac signal analyzer is further configured to: determine the feature by determining at least one of a signal width and a signal area of the detected cardiac electrical signal; compare the feature to the criteria by comparing at least one of the signal width and the signal area to a respective signal width threshold and a signal area threshold; and identify the intrinsic cardiac event by identifying the intrinsic cardiac event when it is determined that at least one of the signal width and the signal area is less than the signal width threshold and the signal area threshold respectively. ### Claim 14 (depends on 9) The device of claim 9, wherein the cardiac signal analyzer is further configured to: establish an intrinsic event waveform template; determine the feature of the sensed electrical signal by determining a waveform morphology of the sensed electrical signal; compare the feature to the criteria by determining a correlation between the waveform morphology and the template and comparing the correlation to a threshold; and identify the intrinsic cardiac event when it is determined that the correlation is greater than the threshold. ### Claim 15 (depends on 9) The device of claim 9, further comprising: a cardiac event sensing module configured to set an auto-adjusting sensing threshold for sensing cardiac events within the electrical signal; and a control module configured to: disable the cardiac event sensing module during the post-stimulation polarization signal; and enable the cardiac signal analyzer during the post-stimulation polarization signal to detect the cardiac electrical signal and identify the intrinsic cardiac event. ### Claim 16 (depends on 15) The device of claim 15, wherein the control module is further configured to re-enable cardiac event sensing module when the post-stimulation polarization signal falls below a threshold. ### Claim 17 (depends on 16) The device of claim 16, wherein the control module is further configured to disable the cardiac signal analyzer when the post-stimulation polarization signal falls below the threshold. ### Claim 18 (depends on 9) The device of claim 9, wherein the therapy delivery module is configured to deliver the electrical stimulation pulse as one of a cardioversion/defibrillation shock pulse and an extracardiac pacing pulse having a pulse energy of at least 1 milliJoule.