# US 2014/0194764 A1 · Twa measuring apparatus and twa measuring method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0194764 A1 - Document ID: US20140194764A1 - Status: Published application - Kind: A1 - Application number: 14/149,968 - Filed: 2014-01-08 - Published: 2014-07-10 - Earliest claimed: 2013-01-10 - Assignees: Nihon Kohden Corporation - Applicants: Nihon Kohden Corporation - Inventors: Tsuneo TAKAYANAGI; Takashi KAIAMI - Web page: https://patentgrep.com/patent/US20140194764A1 ## CPC - A61B 5/355: Detecting T-waves - A61B 5/35: by template matching - A61B 5/7221: {Determining signal validity, reliability or quality (preventing, reducing or removing noise induced by motion artefacts A61B5/7207; noise originating from a therapeutic or surgical apparatus A61B5/7217)} - A61B 5/364: Detecting abnormal ECG interval, e.g. extrasystoles, ectopic heartbeats - A61B 5/366: Detecting abnormal QRS complex, e.g. widening - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract A TWA measuring apparatus includes: a T-wave feature quantity measuring section; a classifying section classifying T-wave feature quantities into groups of odd and even electrocardiogram waveforms; a reliability index calculating section calculating: first and second representative values and first and second dispersion values of the T-wave feature quantities in the odd and even group; a difference between the first and second representative values, to obtain a TWA feature quantity; and an adjustment value between the first representative value and the first dispersion value, and an adjustment value between the second representative value and the second dispersion value, to obtain a reliability index; and a reliability recognizing section recognizing: when the reliability index exceeds a threshold, that reliability of the TWA feature quantity is high; and when the reliability index does not exceed the threshold, that the reliability is low. ## Claims ### Claim 1 A TWA measuring apparatus comprising: a T-wave feature quantity measuring section which is configured to measure T-wave feature quantities of electrocardiogram waveforms acquired from a subject; a classifying section which is configured to classify the T-wave feature quantities into a group of odd electrocardiogram waveforms and a group of even electrocardiogram waveforms; a reliability index calculating section which is configured to calculate: a first representative value and a first dispersion value of the T-wave feature quantities in the group of odd electrocardiogram waveforms, and a second representative value and a second dispersion value of the T-wave feature quantities in the group of even electrocardiogram waveforms; a difference between the first and second representative values, to obtain a TWA feature quantity; and an adjustment value between the first representative value and the first dispersion value, and an adjustment value between the second representative value and the second dispersion value, to obtain a reliability index; and a reliability recognizing section which is configured to recognize: when the reliability index exceeds a threshold, that reliability of the TWA feature quantity is high; and when the reliability index does not exceed the threshold, that the reliability of the TWA feature quantity is low. ### Claim 2 (depends on 1) The TWA measuring apparatus according to claim 1, wherein the reliability index calculating section calculates: when the first representative value is larger than the second representative value, a difference between the first representative value and the first dispersion value, to obtain a first difference value, and a sum of the second representative value and the second dispersion value, to obtain a first sum value; and, when the first representative value is smaller than the second representative value, a difference between the second representative value and the second dispersion value, to obtain a first difference value, and a sum of the first representative value and the first dispersion value, to obtain a first sum value, and the reliability index calculating section calculates a difference between the first difference value and the first sum value, to obtain the reliability index. ### Claim 3 (depends on 1) The TWA measuring apparatus according to claim 1, further comprising: a displaying section which is configured to display the TWA feature quantity and the reliability index. ### Claim 4 A TWA measuring method comprising: measuring T-wave feature quantities of electrocardiogram waveforms acquired from a subject; classifying the T-wave feature quantities into a group of odd electrocardiogram waveforms and a group of even electrocardiogram waveforms; calculating: a first representative value and a first dispersion value of the T-wave feature quantities in the group of odd electrocardiogram waveforms, and a second representative value and a second dispersion value of the T-wave feature quantities in the group of even electrocardiogram waveforms; a difference between the first and second representative values, to obtain a TWA feature quantity; and an adjustment value between the first representative value and the first dispersion value, and an adjustment value between the second representative value and the second dispersion value, to obtain a reliability index; and recognizing: when the reliability index exceeds a threshold, that the reliability of the TWA feature quantity is high; and, when the reliability index does not exceed the threshold, that the reliability of the TWA feature quantity is low. ### Claim 5 (depends on 4) The TWA measuring method according to claim 4, wherein, in the calculating process, when the first representative value is larger than the second representative value, a difference between the first representative value and the first dispersion value is calculated, to obtain a first difference value, and a sum of the second representative value and the second dispersion value is calculated, to obtain a first sum value; and, when the first representative value is smaller than the second representative value, a difference between the second representative value and the second dispersion value is calculated, to obtain a first difference value, and a sum of the first representative value and the first dispersion value is calculated, to obtain a first sum value, and a difference between the first difference value and the first sum value is calculated, to obtain the reliability index. ### Claim 6 (depends on 4) The TWA measuring method according to claim 4, further comprising: displaying the TWA feature quantity and the reliability index. ### Claim 7 (depends on 4) The TWA measuring method according to claim 4, wherein, the measuring process comprises: storing the electrocardiogram waveforms acquired from the subject; and measuring the T-wave feature quantities of the stored electrocardiogram waveforms. ### Claim 8 (depends on 7) The TWA measuring method according to claim 7, wherein the process of measuring the T-wave feature quantities of the stored electrocardiogram waveforms comprises: determining whether, with respect to the stored electrocardiogram waveforms, a beat is a dominant beat or an ectopic beat; and, when a number of the dominant beats is not equal to or larger than a designated number, determining that the measurement is disabled, and, when the number of the dominant beats is equal to or larger than the designated number, extracting an electrocardiograph of a zone where only the dominant beats exist. ### Claim 9 (depends on 4) The TWA measuring method according to claim 4, wherein the first and second representative values and the first and second dispersion values of the T-wave feature quantities are values which are obtained by statistically processing the T-wave feature quantities. ### Claim 10 (depends on 9) The TWA measuring method according to claim 9, wherein each of the first and second representative values of the T-wave feature quantities is an average or medium of the T-wave feature quantities, and each of the first and second dispersion values of the T-wave feature quantities is a standard deviation or root mean square of the T-wave feature quantities. ### Claim 11 (depends on 4) The TWA measuring method according to claim 4, wherein each of the T-wave feature quantities is one of a width, amplitude, area, and frequency of a T-wave of the corresponding one of the electrocardiogram waveforms, or a value which is obtained by performing a four arithmetic operation on an arbitrary combination of the width, amplitude, area, and frequency.