# US 2008/0188761 A1 · Ecg-based identification of impaired ikr kinetics > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2008/0188761 A1 - Document ID: US20080188761A1 - Status: Published application - Kind: A1 - Application number: 11/939,374 - Filed: 2007-11-13 - Published: 2008-08-07 - Earliest claimed: 2006-11-13 - Inventors: Jean-Philippe Couderc - Web page: https://patentgrep.com/patent/US20080188761A1 ## CPC - A61B 5/355: Detecting T-waves - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract A method of assaying impaired delayed rectifier potassium current function is disclosed. One or more electrocardiogram (ECG) signals are obtained. One or more heart rates corresponding to a plurality of beats of the one or more ECG signals are obtained. One or more T-wave amplitudes are determined corresponding to one or more beats of the one or more ECG signals. A determination is made whether the one or more T-wave amplitudes as a function of the one or more heart rates are relatively independent of the corresponding one or more heart rates, thereby indicating impaired delayed rectifier potassium current function. An associated biomarker, system, and method for determining the ability of a pharmacological agent to impair delayed rectifier potassium current function are also disclosed. ## Claims ### Claim 1 A method of assaying impaired delayed rectifier potassium current function, comprising: obtaining one or more electrocardiogram (ECG) signals; obtaining one or more heart rates corresponding to a plurality of beats of the one or more ECG signals; determining one or more T-wave amplitudes corresponding to one or more beats of the one or more ECG signals; and determining whether the one or more T-wave amplitudes as a function of the one or more heart rates are relatively independent of the corresponding one or more heart rates, thereby indicating impaired delayed rectifier potassium current function. ### Claim 2 (depends on 1) The method of claim 1, further comprising: filtering the one or more ECG signals. ### Claim 3 (depends on 2) The method of claim 2, wherein filtering one or more ECG signals comprises low-pass FIR filtering the one or more ECG signals. ### Claim 4 (depends on 2) The method of claim 2, wherein filtering the one or more ECG signals comprises removing a wandering baseline. ### Claim 5 (depends on 2) The method of claim 2, wherein filtering the one or more ECG signals comprises statistically combining multiple beats from the one or more ECG signals. ### Claim 6 (depends on 2) The method of claim 2, wherein filtering the one or more ECG signals comprises discarding one or more leading beats from the one or more ECG signals. ### Claim 7 (depends on 2) The method of claim 2, wherein filtering the one or more ECG signals comprises discarding one or more trailing beats from the one or more ECG signals. ### Claim 8 (depends on 2) The method of claim 2, wherein filtering the one or more ECG signals comprises discarding beats which do not have a corresponding stable heart rate. ### Claim 9 (depends on 8) The method of claim 8, wherein discarding beats which do not have a corresponding stable heart rate comprises discarding beats which have a heart rate that varies by more than a certain percentage in a previous arbitrary time frame. ### Claim 10 (depends on 1) The method of claim 1, wherein determining whether the one or more T-wave amplitudes as a function of the one or more heart rates are relatively independent of the corresponding one or more heart rates comprises: sorting the one or more T-wave amplitudes into heart rate bins; and calculating an average T-wave amplitude for each of the heart rate bins. ### Claim 11 (depends on 10) The method of claim 10, further comprising determining a slope of the average T-wave amplitude versus the heart rate bins. ### Claim 12 (depends on 1) The method of claim 1, wherein determining whether the one or more T-wave amplitudes as a function of the one or more heart rates are relatively independent of the corresponding one or more heart rates comprises plotting the one or more T-wave amplitudes as a function of the corresponding one or more heart rates. ### Claim 13 (depends on 12) The method of claim 12, further comprising determining a slope of the plotted one or more T-wave amplitudes as a function of the corresponding one or more heart rates. ### Claim 14 (depends on 1) A biomarker produced using the method of claim 1. ### Claim 15 (depends on 1) A computer readable medium having stored thereon instructions for assaying impaired delayed rectifier potassium current function, which, when executed by a processor, causes the processor to perform the steps according to claim 1. ### Claim 16 A system for assaying impaired delayed rectifier potassium current function, comprising: a processor configured to determine an indication of impaired delayed rectifier potassium current function based on a comparison of T-wave amplitudes from ECG data with corresponding heart rates for the T-wave amplitudes; a data input coupled to the processor and configured to provide the processor with the ECG data; and a user interface coupled to either the processor or the data input. ### Claim 17 (depends on 16) The system of claim 16, wherein the processor is configured to be at least partially implantable in a subject's body. ### Claim 18 (depends on 16) The system of claim 16, further comprising a database coupled to the processor. ### Claim 19 (depends on 16) The system of claim 16, further comprising a database coupled to the data input. ### Claim 20 (depends on 16) The system of claim 16, further comprising an ECG capture device coupled to the data input. ### Claim 21 (depends on 20) The system of claim 20, wherein the ECG capture device is selected from the group consisting of a Holter monitor; a twelve-lead monitor; an 8 lead monitor; a monitor using a bipolar lead system, and a monitor using a unipolar lead system. ### Claim 22 (depends on 20) The system of claim 20, further comprising a treatment device coupled to the processor, and wherein the processor is further configured to activate the treatment device to attempt to correct a repolarization abnormality indicated by the impaired delayed rectifier potassium current function. ### Claim 23 A method for determining the ability of a pharmacological agent to impair delayed rectifier potassium current function, comprising: obtaining a baseline electrocardiogram (ECG) for a mammal at different heart rates; determining a baseline dependency of a plurality of T-wave amplitudes on corresponding heart rates for the baseline ECG; administering the pharmacological agent to the mammal; obtaining a follow-on ECG for the mammal at different heart rates; determining a follow-on dependency of a plurality of T-wave amplitudes on corresponding heart rates for the follow-on ECG; and comparing the follow-on dependency with the baseline dependency. ### Claim 24 (depends on 23) The method of claim 23, wherein: the baseline dependency is expressed as a baseline slope; the follow-on dependency is expressed as a follow-on slope; and comparing the follow-on dependency with the baseline dependency comprises determining whether the follow-on slope is significantly greater than the baseline slope, thereby indicating that the pharmacological agent has impaired the delayed rectifier potassium current function.