# US 8,540,643 B1 · Method and device for motion and noise immunity in hemodynamic measurement > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,540,643 B1 - Document ID: US8540643B1 - Status: Granted - Kind: B1 - Application number: 12/040,091 - Filed: 2008-02-29 - Granted: 2013-09-24 - Earliest claimed: 2004-06-17 - Assignees: Pacesetter, Inc. - Applicants: Robert Turcott - Inventors: Robert Turcott - Web page: https://patentgrep.com/patent/US8540643B1 ## CPC - A61N 1/3702: {Physiological parameters (A61N1/365 takes precedence; evoked response A61N1/371)} - A61N 1/36514: {controlled by a physiological quantity other than heart potential, e.g. blood pressure (controlled by two or more physical parameters A61N1/36585)} - A61N 1/3925: {Monitoring; Protecting} - A61N 1/39622: {Pacing therapy} - A61N 1/3682: {with a variable atrioventricular delay} - A61N 1/3684: {for stimulating the heart at multiple sites of the ventricle or the atrium} - 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 A method and device, such as an implantable cardiac device, for motion and noise immunity in hemodynamic measurement is presented. The method includes obtaining a template waveform representing hemodynamic performance of a heart during a first hemodynamic state and obtaining an autocharacterization measure from an autocharacterization (e.g., autocorrelation) of the template waveform. The method further includes obtaining a test waveform during a second hemodynamic state, performing a cross-characterization (e.g., cross-correlation) of the template waveform and test waveform to identify a cross-characterization measure, and comparing the autocharacterization measure with the cross-characterization measure as a measurement of hemodynamic status of the second hemodynamic state. The device includes hardware and/or software for performing the described method. ## Claims ### Claim 1 A method of selecting an appropriate anti-arrhythmia therapy for a patient according to a hemodynamic status of the patient, comprising: monitoring electrical activity of the patient's heart to detect an arrhythmia; monitoring hemodynamic performance of the heart, said monitoring comprising: measuring a parameter indicative of hemodynamic performance during a first state to establish a template waveform, obtaining an autocharacterization measure for the template waveform by cross-characterizing the template waveform with itself, measuring the parameter indicative of hemodynamic performance during a second state to establish a test waveform, performing a cross-characterization between the template waveform and the test waveform to identify a cross-characterization measure, comparing the cross-characterization measure with the autocharacterization measure to obtain a comparison result, and obtaining an indication of hemodynamic status based on the comparison result; and selecting, based on said indication of hemodynamic status, the appropriate anti-arrhythmia therapy to treat the arrhythmia. ### Claim 2 (depends on 1) The method of claim 1, wherein the obtaining an autocharacterization measure step comprises obtaining a maximum autocorrelation value for the template waveform. ### Claim 3 (depends on 2) The method of claim 2, wherein the performing step comprises performing a cross-correlation between the template waveform and the test waveform to identify a maximum cross-correlation value for the test waveform, wherein the maximum cross-correlation value comprises the cross-characterization measure. ### Claim 4 (depends on 3) The method of claim 3, wherein the comparing step comprises comparing the maximum cross-correlation value for the test waveform with the maximum autocorrelation value to obtain an indication of hemodynamic status. ### Claim 5 (depends on 4) The method of claim 4, wherein the comparing step comprises comparing a difference between the maximum autocorrelation value and the maximum cross-correlation value for the test waveform against a predetermined threshold. ### Claim 6 (depends on 5) The method of claim 5, wherein the difference comparing step comprises determining if the maximum cross-correlation value for the test waveform is less than the maximum autocorrelation value by a predetermined status low threshold, thereby determining if the hemodynamic status of the second state is low. ### Claim 7 (depends on 5) The method of claim 5, wherein the difference comparing step comprises determining if the maximum cross-correlation value for the test waveform is greater than the maximum autocorrelation value by a predetermined status high threshold, thereby determining if the hemodynamic status of the second state is high. ### Claim 8 (depends on 1) The method of claim 1, wherein the first measuring step comprises measuring a parameter indicative of hemodynamic performance during a normal sinus heart rhythm to establish a template waveform. ### Claim 9 (depends on 8) The method of claim 8, wherein the second measuring step comprises measuring the parameter indicative of hemodynamic performance during a tachycardia rhythm to establish a test waveform. ### Claim 10 (depends on 1) The method of claim 1, wherein the first measuring step comprises measuring a parameter indicative of hemodynamic performance during heart pacing with a baseline atrioventricular (AV) delay. ### Claim 11 (depends on 10) The method of claim 10, wherein the second measuring step comprises measuring the parameter indicative of hemodynamic performance during a test atrioventricular (AV) delay. ### Claim 12 (depends on 1) The method of claim 1, wherein the obtaining an autocharacterization measure step comprises cross-correlating the template waveform with itself to identify a maximum cross-correlation value for the template waveform, wherein the maximum cross-correlation value comprises the autocharacterization measure. ### Claim 13 An implantable cardiac device comprising: means for monitoring electrical activity of a patient's heart to detect an arrhythmia; and a micro-controller configured to monitor hemodynamic performance of the heart, wherein the micro-controller is configured to: obtain a parameter indicative of hemodynamic performance during a first state to establish a template waveform, obtain an autocharacterization measure for the template waveform by cross-characterizing the template waveform with itself, measure the parameter indicative of hemodynamic performance during a second state to establish a test waveform, perform a cross-characterization between the template waveform and the test waveform to identify a cross-characterization measure, compare the cross-characterization measure with the autocharacterization measure to obtain a comparison result, and obtain an indication of hemodynamic status based on the comparison result; and wherein the micro-controller is also configured to select, based on said indication of hemodynamic status, an appropriate anti-arrhythmia therapy to treat the arrhythmia. ### Claim 14 (depends on 13) The implantable cardiac device of claim 13, further comprising: means for delivering the appropriate anti-arrhythmia therapy to the heart. ### Claim 15 (depends on 13) The implantable cardiac device of claim 13, wherein the cross-characterization is a cross-correlation. ### Claim 16 (depends on 15) The implantable cardiac device of claim 15, wherein the cross-characterization measure is a maximum test value of the cross-correlation. ### Claim 17 (depends on 16) The implantable cardiac device of claim 16, wherein the autocharacterization measure is a maximum value of an autocorrelation of the template waveform. ### Claim 18 (depends on 17) The implantable cardiac device of claim 17, wherein to compare the cross-characterization measure with the autocharacterization measure, the micro-controller is configured to compare a difference between the maximum autocorrelation value and maximum test value against a predetermined threshold. ### Claim 19 (depends on 18) The implantable cardiac device of claim 18, wherein to compare a difference between the maximum autocorrelation value and maximum value against the predetermined threshold the micro-controller is configured to determine if the maximum test value is less than the maximum autocorrelation value by a predetermined status low threshold and determine if the hemodynamic status of the second state is low. ### Claim 20 (depends on 18) The implantable cardiac device of claim 18, wherein to compare a difference between the maximum autocorrelation value and maximum value against the predetermined threshold the micro-controller is configured to determine if the maximum test value is greater than the maximum autocorrelation value by a predetermined status high threshold and determine if the hemodynamic status of the second state is high. ### Claim 21 (depends on 13) The implantable cardiac device of claim 13, wherein to obtain an autocharacterization measure, the micro-controller is configured to cross-correlate the template waveform with itself and obtain a maximum cross-correlation value for the template waveform, wherein the maximum cross-correlation value comprises the autocharacterization measure.