Electrocardiogram analyzer, electrocardiogram analysis method, and program

Abstract

When statistical values ​​calculated from a partial measurement section of electrocardiogram data are presented to an analyst, it is possible to prevent abnormalities in electrocardiogram data from being overlooked. [Solution] The electrocardiogram analysis device 3 has a first calculation unit 335 that calculates the difference between at least two feature points related to the position of a predetermined wave in the electrocardiogram data; a second calculation unit 336 that calculates a first statistical value of one or more differences in a specific section in the electrocardiogram data and a second statistical value of the difference different from the first statistical value; an identification unit 334 that identifies a second section in the electrocardiogram data for which the second statistical value satisfies a predetermined judgment condition, provided that the second statistical value in the first section in the electrocardiogram data does not satisfy a predetermined judgment condition, and that is different from the first section that is within a predetermined range based on the first section; and an output unit 339 that associates the first statistical value calculated for at least one of the first and second sections and outputs the calculated first statistical value for that section.

Description

[Technical Field]

[0001] The present invention relates to an electrocardiogram analyzer, an electrocardiogram analysis method, and a program for analyzing an electrocardiogram. [Background technology]

[0002] BACKGROUND ART Conventionally, a Holter electrocardiograph is known which is worn by a subject such as a patient and allows electrocardiogram measurement over a long period of time (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-195693 Summary of the Invention [Problem to be solved by the invention]

[0004] To determine whether an abnormality has occurred in electrocardiogram data, the fluctuation of the interval between the start of the QRS wave and the end of the T wave (also known as the QT interval) is analyzed. Because it is difficult for an analyst to check all of the numerous QT intervals calculated from long-term electrocardiogram data, one possible approach is to sample multiple measurement intervals (e.g., one minute) from the electrocardiogram data at regular intervals (e.g., one hour) to create analysis intervals, and then the analyst checks statistical values ​​(e.g., the average QT interval) for those analysis intervals. However, if statistical values ​​cannot be obtained in a specific measurement interval due to noise or other factors, the analyst may miss an abnormality that has occurred around that measurement interval.

[0005] Therefore, the present invention has been made in consideration of these points, and aims to prevent abnormalities in electrocardiogram data from being overlooked when statistical values ​​calculated from a portion of the measurement section of the electrocardiogram data are presented to an analyst. [Means for solving the problem]

[0006] An electrocardiogram analysis device according to a first aspect of the present invention includes a first calculation unit that calculates a difference between at least two feature points associated with a position of a predetermined wave in electrocardiogram data; a second calculation unit that calculates one or more first statistical values ​​of the differences and a second statistical value of the differences that is different from the first statistical value in a specific section of the electrocardiogram data; an identification unit that, on condition that the second statistical value in a first section of the electrocardiogram data does not satisfy a predetermined judgment condition, identifies a second section in the electrocardiogram data in which the second statistical value satisfies the judgment condition, the second section being different from the first section and within a predetermined range based on the first section; and an output unit that outputs the first statistical value calculated for at least one of the first and second sections, in association with the section.

[0007] The second section may be a section adjacent to or before or after the first section and have the same length as the first section.

[0008] The characteristic point may be a start point, a peak point, or an end point according to the type of wave in each of one or more electrocardiogram waveforms included in the electrocardiogram data.

[0009] The second statistical value may be the number of differences or the standard deviation of the differences, and the judgment condition may be that the number of differences is greater than or equal to a predetermined reference value, or that the standard deviation of the differences is less than or equal to a predetermined reference value.

[0010] The electrocardiogram analysis device may further include an exclusion unit that determines a range in the electrocardiogram data that satisfies a predetermined exclusion condition as an exclusion range, and the second calculation unit may calculate the first statistical value of one or more of the differences in a range in the electrocardiogram data excluding the exclusion range.

[0011] The output unit may cause the information terminal to display the exclusion range and the range excluding the exclusion range in the electrocardiogram data in different display modes.

[0012] The exclusion unit may determine the first section or the second section as the exclusion range on the condition that at least one of the positions of the feature points, the difference, and a statistical value calculated using the positions of the feature points in the first section or the second section is within a predetermined abnormal range.

[0013] The first calculation unit may calculate a first difference, which is the difference between the two feature points of a first type, and a second difference, which is the difference between the two feature points of a second type different from the first type, and the exclusion unit may determine, as the exclusion range, a range in which a relationship between the first difference and the second difference in the electrocardiogram data satisfies a predetermined abnormal condition.

[0014] The electrocardiogram analysis device may further have a receiving unit that receives from a user at the information terminal to which the output unit outputs the first statistical value the designation of the first section or the second section to be excluded, and the exclusion unit may determine the first section or the second section designated by the user as the section to be excluded as the exclusion range.

[0015] The output unit may cause the information terminal to display the first statistical value and the electrocardiogram data from which the first statistical value is calculated on one screen.

[0016] The electrocardiogram analysis device may further include a receiving unit that receives, from a user, a designation of the first section or the second section to be displayed on the information terminal to which the output unit outputs the first statistical value, and the output unit may display the first section or the second section designated by the user as the section to be displayed from the electrocardiogram data from which the first statistical value is calculated.

[0017] The output unit may switch between displaying the time indicating each of the first and second intervals in the electrocardiogram data as the time of day and the elapsed time after a compound is administered to the organism from which the electrocardiogram data was obtained.

[0018] The output unit may output the difference between the first statistical value in the electrocardiogram data obtained from an organism to which a compound has not been administered and the first statistical value in the electrocardiogram data obtained from the organism to which the compound has been administered.

[0019] An electrocardiogram analysis method according to a second aspect of the present invention includes the steps of: calculating a difference between at least two feature points associated with the position of a predetermined wave in electrocardiogram data; calculating one or more first statistical values ​​of the differences and a second statistical value of the differences that is different from the first statistical value in a specific section of the electrocardiogram data; identifying, on condition that the second statistical value in a first section of the electrocardiogram data does not satisfy a predetermined judgment condition, a second section in the electrocardiogram data in which the second statistical value satisfies the judgment condition, the second section being different from the first section and within a predetermined range based on the first section; and outputting the first statistical value calculated for at least one of the first and second sections in association with the section.

[0020] A third aspect of the program of the present invention causes a processor to execute the following steps: calculating a difference between at least two feature points associated with the position of a predetermined wave in electrocardiogram data; calculating one or more first statistical values ​​of the differences and a second statistical value of the differences that is different from the first statistical value in a specific section of the electrocardiogram data; identifying a second section in the electrocardiogram data in which the second statistical value satisfies a predetermined judgment condition, the second section being different from the first section and within a predetermined range based on the first section, on condition that the second statistical value in the first section does not satisfy a predetermined judgment condition; and outputting the first statistical value calculated for the section in association with at least one of the first section and the second section. [Effects of the Invention]

[0021] According to the present invention, when statistical values ​​calculated from a partial measurement section of electrocardiogram data are presented to an analyst, it is possible to prevent abnormalities in the electrocardiogram data from being overlooked. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a diagram for explaining an overview of an electrocardiogram analysis system according to an embodiment. FIG. [Figure 2] 1 is a block diagram of an electrocardiogram analysis system according to an embodiment. [Figure 3] 10 is a schematic diagram for explaining a method in which the acquisition unit separates electrocardiogram data into beat-by-beat data. FIG. [Figure 4] 3 is a schematic diagram for explaining a method by which a classification unit classifies a plurality of electrocardiogram waveforms into a plurality of groups. FIG. [Figure 5] 10 is a schematic diagram for explaining a method in which a receiving unit receives a designation of a reference position in a representative waveform. FIG. [Figure 6] 10 is a schematic diagram for explaining a method in which the specifying unit specifies the correspondence between a representative waveform and an electrocardiogram waveform that is a candidate for analysis. FIG. [Figure 7] 10 is a schematic diagram for explaining a process in which a second calculation unit calculates a first statistical value. FIG. [Figure 8] 10 is a schematic diagram for explaining a process in which a determination unit determines whether or not a second statistical value satisfies a determination condition. FIG. [Figure 9] 10 is a schematic diagram for explaining a process in which an output unit outputs a first statistical value. FIG. [Figure 10] 10 is a schematic diagram for explaining a process in which an output unit outputs additional information. FIG. [Figure 11] 10 is a schematic diagram for explaining a method in which an output unit outputs information indicating a difference relationship between two feature points of two types. FIG. [Figure 12] FIG. 2 is a flowchart illustrating an electrocardiogram analysis method executed by the electrocardiogram analyzer. DETAILED DESCRIPTION OF THE INVENTION

[0023] [Outline of the Electrocardiogram Analysis System S] 1 is a diagram illustrating an overview of an electrocardiogram analysis system S according to this embodiment. The electrocardiogram analysis system S includes an electrocardiograph 1, an information terminal 2, and an electrocardiogram analyzer 3. The electrocardiogram analysis system S may include a plurality of electrocardiographs 1 and a plurality of information terminals 2. The electrocardiogram analysis system S may also include other devices such as a server and a terminal.

[0024] The electrocardiograph 1 is a device that measures the electrocardiogram of the subject's heart. The subject may be, for example, a patient receiving medical treatment, a clinical trial subject, or a living organism, including large animals such as monkeys and dogs. The electrocardiograph 1 is, for example, an inductive electrocardiograph, a Holter monitor, an implantable electrocardiograph, a jacket-type electrocardiograph, an event-type electrocardiograph, or a patch-type electrocardiograph, which measures the subject's electrocardiogram by measuring potentials while attached to the subject's wrist, palm, chest, or the like. In this embodiment, the electrocardiograph 1 is a patch-type electrocardiograph that is attached to the subject's chest and can continuously measure the subject's electrocardiogram during daily life. The electrocardiograph 1 may also be any other device capable of measuring an electrocardiogram, such as a pacemaker, a defibrillator, or an intracardiac electrode.

[0025] In this embodiment, the electrocardiograph 1 transmits electrocardiogram data indicating the measured electrocardiogram to the electrocardiogram analyzer 3 via a network N including a wireless communication line. The electrocardiogram data measured by the electrocardiograph 1 may also be input to the electrocardiogram analyzer 3 using, for example, a storage medium, without going through the network N.

[0026] In this embodiment, the information terminal 2 is a computer used by a user who is an analyst such as a doctor or medical professional. The information terminal 2 has, for example, a display unit such as a liquid crystal display that can display information received from the electrocardiogram analyzer 3, and an operation unit such as a keyboard and mouse that accepts operations by the analyst.

[0027] In this embodiment, the electrocardiogram analyzer 3 is a computer for analyzing the electrical activity of the heart. For example, the electrocardiogram analyzer 3 calculates the difference (QT interval, etc.) between at least two characteristic points (start point of the QRS wave, end point of the T wave, etc.) in the electrocardiogram waveform based on the electrocardiogram data received from the electrocardiograph 1, and outputs information related to the calculated difference (QT interval, etc.).

[0028] The following is an overview of the processing executed by the electrocardiogram analysis system S according to this embodiment. The electrocardiograph 1 measures the electrocardiogram of the subject wearing the electrocardiograph 1. The electrocardiograph 1 transmits electrocardiogram data indicating the measured electrocardiogram to the electrocardiogram analyzer 3.

[0029] The electrocardiogram analyzer 3 receives the electrocardiogram data transmitted by the electrocardiograph 1. The electrocardiogram analyzer 3 separates the received electrocardiogram data (for example, electrocardiogram data measured for one subject over 24 hours) into beat-by-beat data to obtain multiple electrocardiogram waveforms. The electrocardiogram analyzer 3 generates data indicating the electrocardiogram waveform for each beat, for example, by extracting one cycle of waveform from multiple cycles of waveforms included in the received electrocardiogram data.

[0030] The electrocardiogram analyzer 3 classifies the plurality of electrocardiogram waveforms into a plurality of groups based on the similarity of their shapes, for example, by performing a clustering process on the plurality of acquired electrocardiogram waveforms.

[0031] For example, the electrocardiogram analyzer 3 displays a representative waveform, which is at least one representative electrocardiogram waveform belonging to each group, on the information terminal 2, and receives from the analyst a specification of the position (reference position) of a predetermined wave (Q wave, T wave, etc.) on the representative waveform. Based on the position of the predetermined wave on the representative waveform received from the analyst, the electrocardiogram analyzer 3 determines the position of the predetermined wave included in the electrocardiogram waveform to be analyzed.

[0032] The electrocardiogram analyzer 3 calculates the difference between two characteristic points associated with the determined positions of predetermined waves (Q waves, T waves, etc.). The difference between the two characteristic points is, for example, the QT interval, which is the interval between the positions of the Q wave and the T wave (the interval from the start of the QRS wave to the end of the T wave). The electrocardiogram analyzer 3 calculates a first statistical value, which is a statistical value of one or more differences (QT intervals, etc.) included in a first interval, which is a portion of the electrocardiogram data. The first interval is, for example, a one-minute interval based on a reference time point every hour. The first statistical value is, for example, the mean, median, mode, etc. of multiple QT intervals included in the first interval.

[0033] The electrocardiogram analyzer 3 calculates a second statistical value of the difference in the first interval. The second statistical value is a statistical value different from the first statistical value, and is, for example, the number of QT intervals included in the first interval, the standard deviation, or the variance. The electrocardiogram analyzer 3 determines whether the second statistical value satisfies a predetermined determination condition. The determination condition may be, for example, whether the number of QT intervals, which is the second statistical value, is equal to or greater than 1, or whether the standard deviation of the QT intervals is smaller than a reference value.

[0034] For example, on the condition that the second statistical value in the first section does not satisfy the judgment condition, the electrocardiogram analyzer 3 identifies a second section in the electrocardiogram data in which the second statistical value satisfies the judgment condition, the second section being different from the first section within a predetermined range based on the first section. The second section is, for example, a section adjacent to or before the first section, in which the second statistical value of the difference in the section satisfies the judgment condition (for example, a section in which the number of QT intervals, which is the second statistical value, is 1 or more).

[0035] When the electrocardiogram analyzer 3 identifies the second interval, it calculates a first statistical value of one or more differences in the second interval (for example, the average value of multiple QT intervals included in the second interval).

[0036] The electrocardiogram analyzer 3 outputs the first statistical value calculated for at least one of the first and second intervals, for example, in association with the interval. The electrocardiogram analyzer 3 transmits, to the information terminal 2, display information for displaying the first statistical value, for example.

[0037] In this way, the electrocardiogram analysis system S according to this embodiment calculates a first statistical value (such as the average value of QT intervals) of the difference (such as the QT interval) between two feature points in a first interval in electrocardiogram data, and if a second statistical value (such as the number of QT intervals) of the difference in the first interval does not satisfy the judgment condition, calculates a first statistical value of the difference between the two feature points in a second interval different from the first interval. As a result, when presenting statistical values ​​of differences in QT intervals, etc., in the first interval, for example, every hour, to an analyst, even if there is not enough difference in the first interval to calculate an appropriate statistical value, the electrocardiogram analysis system S can present appropriate statistical values ​​to the analyst using the second interval different from the first interval as the analysis interval, thereby preventing the analyst from overlooking abnormalities in the electrocardiogram data.

[0038] [Configuration of the ECG analysis system S] FIG. 2 is a block diagram of an electrocardiogram analysis system S according to this embodiment. In FIG. 2, arrows indicate main data flows, and data flows other than those shown in FIG. 2 may also exist. In FIG. 2, each block indicates a functional configuration rather than a hardware (device) configuration. Therefore, the blocks shown in FIG. 2 may be implemented in a single device, or may be implemented separately in multiple devices. Data may be exchanged between blocks via any means, such as a data bus, a network, or a portable storage medium.

[0039] The electrocardiogram analyzer 3 has a communication unit 31, a storage unit 32, and a control unit 33. The electrocardiogram analyzer 3 may be configured by two or more physically separate devices connected by wire or wirelessly. The electrocardiogram analyzer 3 may also be configured by a cloud, which is a collection of computer resources.

[0040] The communication unit 31 has a communication controller for transmitting and receiving data between the electrocardiograph 1 and the information terminal 2 via the network N. The communication unit 31 notifies the control unit 33 of data received from the electrocardiograph 1 and the information terminal 2 via the network N. The communication unit 31 also transmits data output from the control unit 33 to the information terminal 2 via the network N.

[0041] The storage unit 32 is a storage medium including a ROM (Read Only Memory), a RAM (Random Access Memory), a hard disk drive, etc. The storage unit 32 stores in advance programs to be executed by the control unit 33. The storage unit 32 may be provided outside the electrocardiogram analyzer 3, in which case data may be exchanged between the storage unit 32 and the control unit 33 via a network.

[0042] The control unit 33 includes an acquisition unit 331, a classification unit 332, a reception unit 333, an identification unit 334, a first calculation unit 335, a second calculation unit 336, an exclusion unit 337, a determination unit 338, and an output unit 339. The control unit 33 is a processor such as a CPU (Central Processing Unit), and executes a program stored in the storage unit 32 to function as the acquisition unit 331, the classification unit 332, the reception unit 333, the identification unit 334, the first calculation unit 335, the second calculation unit 336, the exclusion unit 337, the determination unit 338, and the output unit 339. In other words, the acquisition unit 331, the classification unit 332, the reception unit 333, the identification unit 334, the first calculation unit 335, the second calculation unit 336, the exclusion unit 337, the determination unit 338, and the output unit 339 are terms that describe the functions of the control unit 33, and do not necessarily exist physically. At least some of the functions of the control unit 33 may be performed by an electric circuit, or at least some of the functions of the control unit 33 may be realized by the control unit 33 executing a program that is executed via a network.

[0043] The electrocardiogram analysis method executed by the electrocardiogram analysis system S according to this embodiment will be described in detail below. The person to be analyzed wears the electrocardiograph 1. The electrocardiograph 1 measures the electrocardiogram of the person to be analyzed wearing the electrocardiograph 1. The electrocardiograph 1 transmits electrocardiogram data indicating the measured electrocardiogram to the electrocardiogram analyzer 3. The electrocardiograph 1 transmits the electrocardiogram data sequentially to the electrocardiogram analyzer 3, or transmits electrocardiogram data for a predetermined period (e.g., 24 hours) collectively to the electrocardiogram analyzer 3.

[0044] In the electrocardiogram analyzer 3, the acquisition unit 331 receives the electrocardiogram data transmitted by the electrocardiograph 1 via the communication unit 31. The acquisition unit 331 acquires a plurality of electrocardiogram waveforms generated by separating the received electrocardiogram data (i.e., electrocardiogram data of one patient) into beat-by-beat data.

[0045] 3 is a schematic diagram illustrating a method by which the acquiring unit 331 separates the electrocardiogram data into beat-by-beat data. The acquiring unit 331 detects, for example, the position of the peak of an R wave in the electrocardiogram data, and acquires the waveform of the section from a certain time before the peak of an R wave to a certain time before the peak of the next R wave as the electrocardiogram waveform of one beat. The acquiring unit 331 is not limited to the specific method shown here, and may separate the electrocardiogram data into beat-by-beat data using other methods.

[0046] The acquiring unit 331 may perform noise removal processing on the electrocardiogram data. The acquiring unit 331 inputs each of the multiple divided electrocardiograms generated by dividing the electrocardiogram data to a machine learning model that determines whether or not an input electrocardiogram is to be excluded, the machine learning model having been generated in advance by machine learning of an electrocardiogram to be excluded (an electrocardiogram including noise or premature contractions) and an electrocardiogram to be analyzed. The machine learning model determines whether or not an input electrocardiogram is to be excluded. The acquiring unit 331 then acquires multiple electrocardiogram waveforms by separating, for each beat, the divided electrocardiograms determined by the machine learning model not to be excluded.

[0047] Furthermore, the acquiring unit 331 may, for example, exclude electrocardiogram waveforms having a heart rate per unit time greater than or less than a predetermined threshold from among the multiple electrocardiogram waveforms acquired from the electrocardiogram data. Furthermore, the acquiring unit 331 may, for example, perform a wavelet transform on the electrocardiogram data to exclude components in a frequency band of 62.5 Hz to 250 Hz. Furthermore, the acquiring unit 331 may perform a continuous wavelet transform to specify a fine frequency band and exclude components in the specified frequency band. If at least a portion of the electrocardiogram data is excluded by these noise removal processes, a section without an electrocardiogram waveform may occur from the start to the end of the electrocardiogram data.

[0048] In a certain section of an electrocardiogram waveform, the classification unit 332 classifies the multiple electrocardiogram waveforms acquired by the acquisition unit 331 into multiple groups based on the similarity of their shapes. Fig. 4 is a schematic diagram for explaining the method by which the classification unit 332 classifies multiple electrocardiogram waveforms into multiple groups. The left side of Fig. 4 shows multiple electrocardiogram waveforms belonging to each group superimposed, and the right side of Fig. 4 shows a representative waveform (also called a template waveform) of each group.

[0049] The classification unit 332 performs, for example, a known clustering process on the multiple electrocardiogram waveforms acquired by the acquisition unit 331. The clustering process is, for example, a K-Shape method that classifies the multiple electrocardiogram waveforms into multiple clusters so that the distance between the shapes of the electrocardiogram waveforms in each cluster is small. The classification unit 332 determines the multiple clusters generated by the clustering process as multiple groups generated based on the similarity of the shapes.

[0050] The classifier 332 is not limited to the K-Shape method, which is the shape-based clustering method described here, and may classify multiple electrocardiogram waveforms into multiple groups using other methods. The classifier 332 may use other classification methods, not limited to clustering based on shape similarity, as long as it can associate specific positions, such as the end positions of T waves, between multiple electrocardiogram waveforms. The classifier 332 may use other classification methods, such as the K-means method, the DBSCAN method, and hierarchical clustering. The classifier 332 may also classify multiple electrocardiogram waveforms into multiple groups using supervised learning or semi-supervised learning.

[0051] The classification unit 332 may classify multiple electrocardiogram waveforms into multiple groups by combining multiple methods. For example, the K-Shape method may be used to classify the waveforms into 100 clusters, and then other methods of classifying the waveforms into multiple groups may be used to combine the waveforms into the same group if certain conditions are met, ultimately classifying the waveforms into 20 groups. Furthermore, if a predetermined condition is not met, the group may be excluded from the analysis. For example, if there is a group whose representative waveform shape is significantly different from that of the group with the largest number of electrocardiogram waveforms, the group may be excluded.

[0052] The classification unit 332 may combine, for example, information that the RR intervals are close (within a certain range) as a method of combining multiple electrocardiogram waveforms. By classifying multiple electrocardiogram waveforms into multiple groups based on the condition that the RR intervals are close, the classification unit 332 can reduce the possibility of selecting incorrect coordinates when analyzing QT coordinates using the DTW method, which is performed in a later stage. Furthermore, the classification unit 332 may extract feature points related to shape, such as the position coordinates of various inflection points, from the electrocardiogram waveforms and perform dimensionality reduction before classifying the multiple electrocardiogram waveforms into multiple groups. This allows the classification unit 332 to reduce the time required for calculation.

[0053] 4, the multiple electrocardiogram waveforms are classified into a group including electrocardiogram waveforms in which the second T wave of a biphasic T wave is flat near the end, a group including electrocardiogram waveforms in which the second T wave of a biphasic T wave is gradually decreasing near the end, and a group including electrocardiogram waveforms in which the shape of the T wave changes significantly during measurement. The multiple electrocardiogram waveforms are not limited to three groups and may be classified into any number of groups.

[0054] The classification unit 332 extracts, from each of the determined groups, a representative waveform corresponding to at least one electrocardiogram waveform belonging to the group. For example, the classification unit 332 calculates a centroid waveform, which is the center of gravity of the electrocardiogram waveforms belonging to one group, and extracts, as the representative waveform, the electrocardiogram waveform most similar to the centroid waveform from among the electrocardiogram waveforms belonging to the group (e.g., the electrocardiogram waveform having the smallest Euclidean distance from the centroid waveform). The classification unit 332 may also extract the calculated centroid waveform as the representative waveform. The classification unit 332 may also extract, as the representative waveform, multiple electrocardiogram waveforms belonging to one group. After extracting the representative waveform, if there is an electrocardiogram waveform in each group whose degree of matching with the representative waveform is lower than a reference value (e.g., an electrocardiogram waveform whose Euclidean distance from the centroid waveform is greater than a reference value), the classification unit 332 may perform a process of excluding the electrocardiogram waveform from the group.

[0055] The classification unit 332 may extract, as the representative waveform, an electrocardiogram waveform having the smallest DTW distance or SBD distance from the centroid waveform among the multiple electrocardiogram waveforms belonging to the group. The classification unit 332 may extract, as the representative waveform, an electrocardiogram waveform whose RR interval or peak height is within a certain numerical value among one or more electrocardiogram waveforms that satisfy the extraction condition. When evaluation is performed using only the distance function, a waveform with a short RR interval tends to be selected as the representative waveform, but by taking the RR interval into consideration, the classification unit 332 can prevent a waveform that is not preferable as an electrocardiogram waveform from being selected even though it has a short distance from the centroid waveform.

[0056] Instead of a centroid waveform, which is the center of gravity, the classification unit 332 may use a waveform obtained by averaging a plurality of electrocardiogram waveforms belonging to one group, or a waveform created using the median of each point.

[0057] The receiving unit 333 receives a designation of a reference position of a predetermined wave in the representative waveform extracted from each of the plurality of groups. In this embodiment, the predetermined wave is a Q wave or a T wave, but it may be only a Q wave or a T wave, or another type of wave such as an R wave or an S wave.

[0058] 5 is a schematic diagram for explaining a method for accepting a designation of a reference position in a representative waveform by the accepting unit 333. The accepting unit 333 transmits information indicating a representative waveform of a selected group, which is, for example, any one group selected from a plurality of groups, to the information terminal 2 via the communication unit 31.

[0059] The information terminal 2 displays the representative waveform on the display unit based on the information received from the electrocardiogram analyzer 3. The information terminal 2 receives an operation from the analyst on the operation unit to specify the reference positions (here, the start point of the QRS wave and the end point of the T wave) of predetermined waves (here, the Q wave and the T wave). The information terminal 2 transmits information indicating the reference positions specified by the analyst to the electrocardiogram analyzer 3.

[0060] In the electrocardiogram analyzer 3, the receiving unit 333 receives the reference position indicated by the information received from the information terminal 2 via the communication unit 31 as the reference position of a predetermined wave. When the receiving unit 333 has not received reference positions for all of the multiple groups, it transmits information indicating a representative waveform of another selected group from the multiple groups to the information terminal 2 via the communication unit 31 and receives the designation of the reference position. When the receiving unit 333 has received reference positions for all of the multiple groups, it stops receiving the designation of the reference position.

[0061] The identification unit 334 performs the following processes by treating each of the multiple electrocardiogram waveforms belonging to one group as an electrocardiogram waveform of an analysis target candidate. The identification unit 334 identifies the correspondence between multiple positions on the time axis of the representative waveform of the group to which the electrocardiogram waveform of the analysis target candidate belongs and multiple positions on the time axis of the electrocardiogram waveform of the analysis target candidate.

[0062] 6 is a schematic diagram illustrating a method by which the identification unit 334 identifies the correspondence between the representative waveform and an electrocardiogram waveform that is a candidate for analysis. The identification unit 334 calculates the distance between multiple points (coordinates) arranged at predetermined time intervals on the representative waveform and multiple points arranged at predetermined time intervals on the electrocardiogram waveform of the candidate for analysis, using, for example, the DTW method, in a round-robin manner. The identification unit 334 sequentially associates the multiple points on the representative waveform with the multiple points on the electrocardiogram waveform of the candidate for analysis so as to minimize the sum of the calculated distances. FIG. 6 shows line segments (also called warping paths) connecting points on the electrocardiogram waveform of the candidate for analysis with points on the representative waveform that correspond to those points.

[0063] The identification unit 334 identifies, as a correspondence relationship, a combination of each of a plurality of points in the electrocardiogram waveform of the analysis target candidate and a point in the representative waveform associated with that point. The identification unit 334 is not limited to the specific method shown here, and may identify the correspondence relationship between the representative waveform and the analysis target candidate by other methods.

[0064] The identifying unit 334 determines the position in the electrocardiogram waveform of the analysis candidate that corresponds to the reference position in the representative waveform, as the position of the predetermined wave included in the electrocardiogram waveform of the analysis candidate. That is, the identifying unit 334 determines the position of the predetermined wave included in the electrocardiogram waveform of the analysis candidate by identifying where in the electrocardiogram waveform of the analysis candidate the reference position of the predetermined wave specified in the representative waveform corresponds.

[0065] 6, the identification unit 334 determines that the corresponding position of the Q wave (starting point of the QRS wave) included in the electrocardiogram waveform of the analysis candidate is the sixth point on the electrocardiogram waveform of the analysis candidate because the reference position of the Q wave (starting point of the QRS wave) is the sixth point on the representative waveform, and the sixth point on the representative waveform corresponds to the sixth point on the electrocardiogram waveform of the analysis candidate. The identification unit 334 determines that the corresponding position of the T wave (ending point of the T wave) included in the electrocardiogram waveform of the analysis candidate is the 54th point on the electrocardiogram waveform of the analysis candidate because the reference position of the T wave (ending point of the T wave) is the 57th point on the representative waveform, and the 57th point on the representative waveform corresponds to the 54th point on the electrocardiogram waveform of the analysis candidate.

[0066] The first calculation unit 335 calculates the difference (hereinafter simply referred to as the difference) between at least two feature points associated with the position of a predetermined wave included in the electrocardiogram waveform of the analysis target candidate in the electrocardiogram data. The feature points associated with the position of the predetermined wave are, for example, the start point, peak, or end point according to the type of wave in each of one or more electrocardiogram waveforms included in the electrocardiogram data. The start point, peak, or end point according to the type of wave is predetermined, such as the start point of a QRS wave, the end point of a T wave, or the start point of a P wave. The difference between two feature points is the width (time interval) between the start point, peak, or end point of the two predetermined waves.

[0067] The predetermined wave is, for example, a QRS wave, a Q wave, a T wave, an R wave, an S wave, a P wave, etc. in an electrocardiogram waveform. The difference between two characteristic points is, for example, a QT interval (the distance between the start point of a QRS wave and the end point of a T wave), a PR interval (the distance between the start point of a P wave and the start point of a QRS wave) (also called a PQ interval), a QRS width (the distance between the start point of a QRS wave and the end point of a QRS wave), a JT interval (the distance between the end point of an S wave (J point) and the end point of a T wave), a Tp-e (the distance between the apex of a T wave and the end point of a T wave), a ST (the distance between the J point and an equipotential line), etc.

[0068] In the example shown below, the position of the Q wave (start point of the QRS wave) and the position of the T wave (end point of the T wave) are used as at least two feature points related to the position of a predetermined wave included in the electrocardiogram waveform of the analysis target candidate, and the QT interval is used as the difference between the two feature points. The first calculation unit 335 calculates, as the difference between the two feature points, at least one of the QT interval (hereinafter, QT), which is the interval between the position of the Q wave and the position of the T wave in one electrocardiogram waveform, and a corrected interval calculated by correcting the QT using the heart rate identified from the electrocardiogram waveform of the analysis target candidate.

[0069] The first calculation unit 335 calculates multiple QT intervals by, for example, subtracting the position of the Q wave from the position of the T wave for each of multiple electrocardiogram waveforms included in the electrocardiogram data (if the electrocardiogram data includes only one electrocardiogram waveform or if many electrocardiogram waveforms have been excluded, then one QT interval is calculated). The first calculation unit 335 calculates the corrected interval (QTc) using, for example, the following formula (1) proposed by Bazett. The QTc calculated using formula (1) is also referred to as QTcB.

number

[0070] RR (RR interval) is the interval between R waves in two consecutive electrocardiogram waveforms, and is the reciprocal of the heart rate. The first calculation unit 335 may also calculate QTc using other known formulas, such as the Fridericia correction formula, the Hodges correction formula, or the Framingham correction formula.

[0071] The second calculation unit 336 calculates a first statistical value of one or more differences between at least two feature points in a plurality of electrocardiogram waveforms included in a first section of the electrocardiogram data. Fig. 7 is a schematic diagram for explaining the process of the second calculation unit 336 calculating the first statistical value.

[0072] The first interval is an interval of a predetermined length in the electrocardiogram data, and is an interval used to calculate a statistical value of one or more differences between two feature points. The first interval is, for example, an interval of a predetermined length based on a reference time point. The reference time point is, for example, a plurality of time points set at predetermined intervals (30 minutes, 1 hour, etc.), and is a time point represented by the elapsed time from the start time of measurement of the electrocardiogram data or the time of medication.

[0073] The first interval is, for example, an interval of a predetermined length (30 seconds, 1 minute, etc.) that starts or ends at a reference time point. In the example shown below, a 1-minute interval that starts at a reference time point set every hour is used as the first interval.

[0074] The first statistical value is a statistical value calculated from one or more differences between two feature points included in the first interval. The first statistical value is a statistical value that represents the characteristics of the electrocardiogram waveform of the subject. By referring to the first statistical value, a doctor or other person can determine whether the subject has an electrocardiogram abnormality such as QT prolongation, PR interval prolongation, abnormal QRS width, ST elevation, or arrhythmia. The first statistical value is, for example, a mean value, a median value, a mode value, or the like. In the example of FIG. 7, the second calculation unit 336 calculates the mean value of multiple QTs included in the first interval as the first statistical value.

[0075] The second calculation unit 336 may calculate the first statistical value after excluding a range that satisfies a predetermined exclusion condition from the electrocardiogram data. In this case, the exclusion unit 337 determines the range that satisfies the predetermined exclusion condition to be excluded from the analysis interval of the electrocardiogram data as the exclusion range.

[0076] The exclusion unit 337 determines the first section as the exclusion range on the condition that, for example, at least one of the positions of the feature points in the first section, the difference, and the statistical value calculated using the positions of the feature points is within a predetermined abnormal range (a range in which values ​​included therein are determined to be abnormal). The exclusion unit 337 determines the first section as the exclusion range when, for example, the distance between the position of any feature point in the first section (such as the start point of a QRS wave or the end point of a T wave) and the position of the feature point in the representative waveform is equal to or greater than a predetermined value. The exclusion unit 337 may also calculate a statistical value (such as a standard deviation or variance) different from the first statistical value for the positions of multiple feature points in the first section, and determine the first section as the exclusion range when the calculated statistical value is equal to or greater than a predetermined value.

[0077] Alternatively, the exclusion unit 337 may determine the exclusion range based on the difference between two feature points of two types. In this case, the first calculation unit 335 calculates a first difference, which is the difference between two feature points of a first type, and a second difference, which is the difference between two feature points of a second type different from the first type. For example, the first difference is the above-mentioned QT, and the second difference is the above-mentioned RR.

[0078] The exclusion unit 337 determines, as the exclusion range, a range in which the relationship between the first difference and the second difference in the electrocardiogram data satisfies a predetermined abnormal condition (a condition that determines that the relationship between the first difference and the second difference is abnormal). For example, the exclusion unit 337 linearly approximates the relationship between QT, which is the first difference, and RR, which is the second difference, and determines, as the exclusion range, a range in the electrocardiogram data that includes a feature point whose distance from the approximation line is equal to or greater than a predetermined value, as abnormal.

[0079] The second calculation unit 336 calculates a first statistical value (for example, an average value of QT) of a plurality of differences (for example, QT) between two feature points in a range of the electrocardiogram data excluding the exclusion range determined by the exclusion unit 337. This allows the electrocardiogram analysis system S to calculate the first statistical value by excluding a range in the electrocardiogram data where the positions of feature points, etc. may be abnormal, thereby improving the accuracy of the first statistical value.

[0080] The second calculation unit 336 calculates a second statistical value of the difference between two feature points in the first interval. The determination unit 338 determines whether the calculated second statistical value satisfies a predetermined determination condition. The determination condition is a condition for identifying each first interval as an analysis interval of electrocardiogram data, and in this case, a condition for adopting the first statistical value in the first interval.

[0081] 8 is a schematic diagram illustrating a process in which the determination unit 338 determines whether a second statistical value satisfies a determination condition. The second statistical value is, for example, a statistical value different from the first statistical value and is used to determine whether to adopt a first statistical value in a first interval that has not been excluded by the exclusion unit 337. The second statistical value is, for example, the number of differences (e.g., QT) between two feature points in a plurality of electrocardiogram waveforms included in the first interval, a standard deviation, a variance, or the like. The determination condition is, for example, that the number of differences, which are the second statistical value, is equal to or greater than a predetermined reference value, or that the standard deviation of the differences, which are the second statistical value, is equal to or less than a predetermined reference value. The reference value is, for example, stored in advance in the storage unit 32.

[0082] The condition for determining the number of differences is, for example, 1 or more, more preferably 3 or more. By setting the condition that the number of differences is 3 or more, the electrocardiogram analysis system S can ensure a sufficient number of differences for calculating the average value and suppress the variation in the data. The condition for determining the standard deviation of the differences is, for example, 30 ms or less.

[0083] For example, the determination unit 338 determines that the second statistical value satisfies the determination condition when the number of differences, which is the second statistical value, is equal to or greater than a reference value, and determines that the second statistical value does not satisfy the determination condition when the number of differences, which is the second statistical value, is smaller than the reference value. For example, the determination unit 338 determines that the second statistical value satisfies the determination condition when the standard deviation of the differences, which is the second statistical value, is equal to or smaller than a reference value, and determines that the second statistical value does not satisfy the determination condition when the standard deviation of the differences, which is the second statistical value, is larger than the reference value.

[0084] The identifying unit 334 includes a first interval in the analysis interval on the condition that the determining unit 338 determines that the second statistical value in the first interval satisfies the determination condition (i.e., the condition for adopting the first statistical value in the first interval). On the other hand, on the condition that the determining unit 338 determines that the second statistical value in the first interval does not satisfy the determination condition, the identifying unit 334 does not include the first interval in the analysis interval and identifies a second interval in the electrocardiogram data in which the second statistical value satisfies the determination condition, which is different from the first interval that is within a predetermined range based on the first interval.

[0085] The identification unit 334 identifies, for example, a section adjacent to or before the first section and having the same length as the first section as a candidate for the second section. In the example of Fig. 8, the second statistical value in the first section of a predetermined length starting from the reference time point did not satisfy the determination condition, so the identification unit 334 identifies a section of the same length that is adjacent to and before the first section as a candidate for the second section.

[0086] Furthermore, the second calculation unit 336 calculates a second statistical value (the number of differences or the standard deviation of the differences) for the second section candidate identified by the identification unit 334. The determination unit 338 determines whether the calculated second statistical value satisfies the above-mentioned determination condition. On the condition that the determination unit 338 determines that the second statistical value for the second section candidate does not satisfy the determination condition, the identification unit 334 identifies the section adjacent to the first section or the second section candidate before or after it as the next second section candidate. The determination unit 338 repeats the determination of whether the next second section candidate satisfies the determination condition.

[0087] The closer the second section is to the first section, the better. The second section is preferably within 15 minutes before and after the range of the first section, and more preferably within 5 minutes before and after. This allows the electrocardiogram analysis system S to prevent the analyst from overlooking abnormal information occurring near the first section.

[0088] The identification unit 334 officially identifies the candidate second section as the second section and includes the second section in the analysis section, on the condition that the determination unit 338 determines that the second statistical value in the candidate second section satisfies the determination condition. As a result, the electrocardiogram waveforms of the analysis target candidates included in the first section and the second section officially identified as the analysis section become the official analysis targets.

[0089] The second calculation unit 336 calculates a first statistical value of one or more differences between two feature points in multiple electrocardiogram waveforms included in the second interval identified by the identification unit 334 (the second interval identified as the analysis interval). The first statistical value calculated for the second interval is the same as the first statistical value calculated for the first interval, and is, for example, an average value or a median value. In the example of FIG. 8, the second calculation unit 336 calculates the average value of multiple QTs included in the second interval as the first statistical value.

[0090] The second calculation unit 336 may calculate the first statistical value after excluding a range in the electrocardiogram data that satisfies a predetermined exclusion condition. In this case, the exclusion unit 337 determines the range in the electrocardiogram data that satisfies the predetermined exclusion condition as the exclusion range.

[0091] The exclusion unit 337 determines the second section as the exclusion range, for example, on the condition that at least one of the positions of the feature points in the second section, the difference, and the statistical value calculated using the positions of the feature points is within a predetermined abnormal range. The exclusion unit 337 determines the second section as the exclusion range, for example, when the distance between the position of any feature point in the second section (the start point of the QRS wave, the end point of the T wave, etc.) and the position of the feature point in the representative waveform is equal to or greater than a predetermined value. Furthermore, the exclusion unit 337 calculates a statistical value (such as a standard deviation or variance) different from the first statistical value for the positions of the multiple feature points in the second section, and determines the second section as the exclusion range if the calculated statistical value is equal to or greater than a predetermined value.

[0092] Alternatively, the exclusion unit 337 may determine the exclusion range based on the difference between two feature points of two types. In this case, the first calculation unit 335 calculates a first difference, which is the difference between two feature points of a first type, and a second difference, which is the difference between two feature points of a second type different from the first type. For example, the first difference is the above-mentioned QT, and the second difference is the above-mentioned RR.

[0093] The exclusion unit 337 determines, as an exclusion range, a range in which the relationship between the first difference and the second difference in the electrocardiogram data satisfies a predetermined abnormal condition. For example, the exclusion unit 337 linearly approximates the relationship between the first difference QT and the second difference RR, and determines, as an exclusion range, a range in the electrocardiogram data that includes a feature point whose distance from the approximation line is equal to or greater than a predetermined value as abnormal.

[0094] The second calculation unit 336 calculates a first statistical value of one or more differences between two feature points in a plurality of electrocardiogram waveforms (electrocardiogram waveforms to be analyzed) included in a range in the electrocardiogram data excluding the exclusion range determined by the exclusion unit 337. This allows the electrocardiogram analysis system S to calculate the first statistical value by excluding a range in the electrocardiogram data where the positions of the feature points may be abnormal, thereby improving the accuracy of the first statistical value.

[0095] The output unit 339 associates one or more first statistical values ​​of differences calculated for the electrocardiogram waveform to be analyzed in at least one of the first and second intervals (i.e., each interval identified as an analysis interval), and outputs the first statistical value of one or more differences calculated for the electrocardiogram waveform to be analyzed in the interval. For example, when the determination unit 338 determines that the second statistical value in the first interval satisfies the determination condition, the output unit 339 outputs the first statistical value in the first interval, and when the determination unit 338 determines that the second statistical value in the first interval does not satisfy the determination condition, the output unit 339 outputs the first statistical value in the second interval.

[0096] 9 is a schematic diagram for explaining a process in which the output unit 339 outputs the first statistical value. In this embodiment, the output unit 339 transmits display information for displaying at least one of the first and second intervals in association with the first statistical value for that interval to the information terminal 2. The information terminal 2 displays at least one of the first and second intervals in association with the statistical value for that interval on the display unit in accordance with the display information transmitted from the multiple electrocardiographs 1.

[0097] 9, the output unit 339 displays, on the information terminal 2, a calculation range indicating each of a plurality of first or second intervals (one minute based on a reference time point every hour after the start of measurement) and a first statistical value (here, QTc average) in the calculation range. Here, one hour after the start of measurement is the first interval from the display of the calculation range, two hours after the start of measurement is the second interval immediately before the first interval, and three hours after the start of measurement is the second interval immediately after the first interval.

[0098] The output unit 339 may output data (text data, binary data, etc.) that associates at least one of the first interval and the second interval with the first statistical value in that interval.

[0099] As a result, even if the electrocardiogram analysis system S has no electrocardiogram waveform in the first section as a result of noise removal processing, and the first statistical value for that first section cannot be calculated (in the example of Figure 9, 2 hours and 3 hours after the start of measurement), it can calculate the first statistical value in the second section surrounding the first section, thereby preventing the first statistical value from being missing in a specific section.

[0100] 9, the output unit 339 also displays on the information terminal 2 the standard deviation of QTc, which is a second statistical value different from the first statistical value (QTc average) for the first or second interval, along with the time since the start of measurement indicating the first and second intervals. This allows the user to confirm that the displayed first and second intervals satisfy the criteria for identifying the analysis interval (i.e., the standard deviation being smaller than a reference value). Here, the output unit 339 may, for example, switch between displaying the time indicating the first and second intervals in the electrocardiogram data as time (date and time) and the elapsed time after the administration of a compound to the organism from which the electrocardiogram data was obtained. This allows the electrocardiogram analysis system S to easily analyze the timing at which the first statistical value changes.

[0101] In this embodiment, the user refers to at least one of the first and second intervals and the first statistical value (QTc average) for that interval on the information terminal 2. If the user determines that one of the first statistical values ​​is abnormal, the user performs an operation on the operation unit of the information terminal 2 to designate the first or second interval corresponding to that first statistical value as an interval to be excluded. In the example of FIG. 9, the user selects a check box (or a button) associated with the first or second interval to be excluded (here, the QTc value for the second interval, 3 hours after the start of measurement, is determined to be abnormal, and the exclusion check box is selected).

[0102] The information terminal 2 may switch between displaying a customer screen with limited functionality and an administrator screen with unlimited functionality, depending on the attributes of the user using the information terminal 2. In this case, the information terminal 2 may not accept an operation to designate an exclusion target on the customer screen, but may accept an operation to designate an exclusion target on the administrator screen.

[0103] In this embodiment, the information terminal 2 transmits operation information indicating an operation by the user to the electrocardiogram analyzer 3. In the electrocardiogram analyzer 3, the receiving unit 333 receives, from the user, a designation of the first section or the second section to be excluded, based on the information transmitted by the information terminal 2.

[0104] The exclusion unit 337 determines the first or second interval designated by the user as the exclusion target as the exclusion range. The identification unit 334 again identifies an analysis interval within the range of the electrocardiogram data excluding the exclusion range determined by the exclusion unit 337. As a result, the electrocardiogram waveform included in the analysis interval becomes the final analysis target. The second calculation unit 336 calculates a first statistical value of one or more differences between two feature points in the analysis interval identified by the identification unit 334.

[0105] The output unit 339 outputs the first statistical value calculated in the range excluding the exclusion range, instead of the first statistical value calculated while including the exclusion range. Furthermore, the output unit 339 may output a list of the first intervals or second intervals within the exclusion range. This allows the electrocardiogram analysis system S to calculate the first statistical value excluding the range specified by the user.

[0106] The output unit 339 may display the additional information related to the first statistical value on the information terminal 2. Fig. 10 is a schematic diagram for explaining the process in which the output unit 339 outputs the additional information.

[0107] In this embodiment, the output unit 339 displays, for example, the first statistical value (QTc average) and the electrocardiogram data from which the first statistical value is calculated on one screen on the information terminal 2. The user also performs an operation on the operation unit of the information terminal 2 to specify the first or second interval of the electrocardiogram data to be displayed. In the example of Fig. 10, the user selects the row representing the first or second interval to be displayed.

[0108] The information terminal 2 transmits operation information indicating an operation by the user to the electrocardiogram analyzer 3. In the electrocardiogram analyzer 3, the receiving unit 333 receives, from the user, designation of the first section or the second section to be displayed, based on the information transmitted by the information terminal 2.

[0109] The output unit 339 displays the first or second interval designated by the user as the display target from the electrocardiogram data from which the first statistical value is calculated. For example, the output unit 339 enlarges a predetermined range of the electrocardiogram data including the first or second interval designated by the user as the display target, and displays it on the information terminal 2. This allows the electrocardiogram analysis system S to make it easier for the user to understand the interval on which the user is focusing and the electrocardiogram data from which the first statistical value is based.

[0110] The output unit 339 may display, on the information terminal 2, the exclusion range determined by the exclusion unit 337 and the range excluding the exclusion range in different display modes (colors, patterns, etc.). In the example of FIG. 10, the output unit 339 displays the exclusion range (the first section in which the determination unit 338 determines that the second statistical value does not satisfy the determination condition) of the electrocardiogram data in a predetermined color (stippled). This allows the electrocardiogram analysis system S to easily grasp the range of the electrocardiogram data that was excluded from the calculation of the first statistical value. Furthermore, the output unit 339 may delete the portion of the electrocardiogram data that corresponds to the exclusion range and display it on the information terminal 2.

[0111] Here, the output unit 339 may change the display mode (color, pattern, etc.) of the exclusion range in the electrocardiogram data depending on the reason for determining the exclusion range by the exclusion unit 337. For example, the output unit 339 determines that the determination condition is not satisfied by the determination unit 338 based on the positions of the feature points, and causes the information terminal 2 to display the exclusion range determined to be excluded by the exclusion unit 337 and the exclusion range determined based on a user specification in different colors. This allows the electrocardiogram analysis system S to easily allow the user to understand the reason for exclusion of each exclusion range in the electrocardiogram data.

[0112] Furthermore, the output unit 339 may cause the information terminal 2 to display a graph showing the first statistical value for each elapsed time (for example, "QTc interval trend" in FIG. 10). In this case, the output unit 339 may cause the information terminal 2 to display the exclusion range determined by the exclusion unit 337 and the range excluding the exclusion range in different display modes (colors, patterns, etc.) in the graph showing the first statistical value for each elapsed time. Furthermore, the output unit 339 may cause the display mode (colors, patterns, etc.) of the exclusion range in the graph showing the first statistical value for each elapsed time to differ depending on the reason for the determination of the exclusion range by the exclusion unit 337 (determination by the determination unit 338 or specification by the user).

[0113] The output unit 339 may output the difference between the first statistical value when a compound such as a pharmaceutical is administered to the subject and the first statistical value when the compound is not administered to the subject. In this case, the acquisition unit 331 acquires administration electrocardiogram data measured when the compound is administered to the subject and non-administration electrocardiogram data measured when the compound is not administered to the subject.

[0114] Second calculation unit 336 calculates a first statistical value in the first interval or the second interval for each of the on-administration electrocardiogram data and the non-administration electrocardiogram data. Output unit 339 displays the difference between the first statistical value in each of the multiple intervals in the on-administration electrocardiogram data and the first statistical value in each of the multiple intervals in the non-administration electrocardiogram data on information terminal 2. Output unit 339 outputs the difference between the first statistical values ​​in the intervals of the same time, for example, by matching the times when measurement of the on-administration electrocardiogram data and the non-administration electrocardiogram data started.

[0115] In addition, the output unit 339 may output information indicating a specific interval, provided that the difference between the first statistical value when the compound is administered and the first statistical value when the compound is not administered in that interval is greater than or equal to a predetermined threshold.

[0116] This allows the electrocardiogram analysis system S to present to the user the difference in the first statistical value between when the compound is administered and when the compound is not administered in each section, making it easier for the user to analyze the effect of the compound on the first statistical value.

[0117] The output unit 339 may output information indicating the relationship of the difference between two feature points of two types. Fig. 11 is a schematic diagram for explaining a method in which the output unit 339 outputs information indicating the relationship of the difference between two feature points of two types.

[0118] In this case, the first calculation unit 335 calculates a first difference, which is the difference between two feature points of a first type, and a second difference, which is the difference between two feature points of a second type different from the first type. For example, the first difference is the above-mentioned QTc, and the second difference is the above-mentioned RR. The output unit 339 causes the information terminal 2 to display a graph showing the relationship between the first difference and the second difference.

[0119] In the example of Fig. 11, the output unit 339 displays a graph in which points indicating QT and RR are plotted on a two-dimensional plane. In Fig. 11, the horizontal axis represents RR, and the vertical axis represents QT. This allows the electrocardiogram analysis system S to easily allow the user to analyze the relationship between the differences between the two types of feature points.

[0120] Furthermore, the output unit 339 may display one or more points belonging to each of the groups (clusters) determined by the classification unit 332 in a different display mode (e.g., color, shape, etc.). In the example of FIG. 11, the output unit 339 displays multiple points belonging to Group 1 and multiple points belonging to Group 2 in different colors. This allows the electrocardiogram analysis system S to easily analyze the trend of differences between two feature points for each group. Specifically, from a physiological perspective, QT and RR often have a linear relationship. If the graph output by the output unit 339 shows that QT and RR are not linear and their dependency differs between groups, it is possible that a specific abnormality has occurred in that group or that QT analysis for that group has failed (e.g., due to an inadequate specification of the onset of the QRS wave or the end of the T wave in the representative waveform). In such cases, the analyst can properly understand the QT and RR characteristics specific to that group by checking whether there were any errors in the designation of the start point of the QRS wave or the end point of the T wave in the representative waveform.

[0121] The output unit 339 may display the first statistical value and the representative waveforms of each of the multiple groups determined by the classification unit 332 on one screen on the information terminal 2. This allows the electrocardiogram analysis system S to make it easier for the user to understand the tendency of the electrocardiogram waveforms included in the electrocardiogram data.

[0122] The accepting unit 333 may accept an operation from the user to modify the position of a feature point on the representative waveform of each of the multiple groups displayed on the information terminal 2. The first calculating unit 335 uses the modified position of the feature point in the representative waveform of one of the groups to modify the position of the feature point in each of the multiple electrocardiogram waveforms belonging to the group, and recalculates the difference between the two feature points using the modified position of the feature point. The second calculating unit 336 calculates a first statistical value in the first interval or the second interval using the recalculated difference between the two feature points. In this way, the electrocardiogram analysis system S can modify the first statistical value of the electrocardiogram waveforms belonging to a specific group in response to the user modifying the position of the feature point in the specific group.

[0123] The determination unit 338 may determine whether or not the representative waveform of each of the plurality of groups contains characteristics of arrhythmia such as premature contractions according to a predetermined rule. In this case, the output unit 339 causes the information terminal 2 to display the number of electrocardiogram waveforms belonging to a group corresponding to a representative waveform determined by the determination unit 338 to contain characteristics of arrhythmia, in association with the group. This allows the electrocardiogram analysis system S to notify the user of a group of electrocardiogram waveforms that may be arrhythmia, and to assist the user in determining whether or not the user has an arrhythmia.

[0124] [Flowchart of electrocardiogram analysis method] 12 is a flowchart of an electrocardiogram analysis method executed by the electrocardiogram analyzer 3 according to this embodiment. The electrocardiograph 1 measures the electrocardiogram of the subject wearing the electrocardiograph 1. The electrocardiograph 1 transmits electrocardiogram data indicating the measured electrocardiogram to the electrocardiogram analyzer 3. In the electrocardiogram analyzer 3, the acquisition unit 331 receives the electrocardiogram data (electrocardiogram data to be analyzed) transmitted by the electrocardiograph 1 via the communication unit 31 (S11). The acquisition unit 331 acquires multiple electrocardiogram waveforms generated by separating the received electrocardiogram data into beat-by-beat data.

[0125] The classification unit 332 classifies the multiple electrocardiogram waveforms acquired by the acquisition unit 331 into multiple groups based on the similarity of their shapes. The reception unit 333 receives designation of reference positions (e.g., the start of the QRS wave, the end of the T wave) of predetermined waves (e.g., Q wave, T wave) in the representative waveform extracted from each of the multiple groups. The identification unit 334 identifies the positions of at least two feature points in the electrocardiogram waveform to be analyzed by determining the correspondence between multiple positions on the time axis (e.g., positions between the start of the QRS wave and the end of the T wave) in the representative waveform of the group to which the electrocardiogram waveform to be analyzed belongs and multiple positions on the time axis (e.g., positions between the start of the QRS wave and the end of the T wave) in the electrocardiogram waveform to be analyzed (S12).

[0126] The first calculation unit 335 calculates the difference (such as QT) between two feature points associated with the positions of predetermined waves in the electrocardiogram data (S13). The second calculation unit 336 calculates a first statistical value (such as the average QT) of one or more differences between the two feature points in a first section of the electrocardiogram data (S14).

[0127] The second calculation unit 336 calculates a second statistical value (such as the standard deviation of QT) of the difference between two feature points in the first interval (S15). The determination unit 338 determines whether the calculated second statistical value satisfies a predetermined determination condition that identifies the analysis interval. If the determination unit 338 determines that the second statistical value in the first interval satisfies the determination condition (YES in S16), the electrocardiogram analyzer 3 proceeds to step S19.

[0128] If the determination unit 338 determines that the second statistical value in the first interval does not satisfy the determination condition (NO in S16), the identification unit 334 identifies a second interval in the electrocardiogram data in which the second statistical value satisfies the determination condition, for example, a second interval different from the first interval that is within a predetermined range based on the first interval (here, a second interval before or after the first interval) (S17). The second calculation unit 336 calculates a first statistical value of one or more differences between two feature points in the second interval identified by the identification unit 334 (S18).

[0129] After the process of calculating the first statistical value from the start point to the end point of the electrocardiogram data to be analyzed is completed, the output unit 339 outputs the first statistical value calculated for the section in association with at least one of the first section and the second section (S19).

[0130] [Effects of the embodiment] According to the electrocardiogram analysis system S of this embodiment, the electrocardiogram analyzer 3 calculates a first statistical value of the difference between two feature points in a first interval in the electrocardiogram data, and if a second statistical value of the difference in the first interval does not satisfy the judgment condition, calculates a first statistical value of the difference between the two feature points in a second interval different from the first interval. As a result, when presenting statistical values ​​of differences such as QT intervals in the first interval, for example, every hour, to an analyst, even if there is not enough difference in the first interval to calculate an appropriate statistical value and the first interval is unsuitable as an analysis interval, the electrocardiogram analysis system S can present appropriate statistical values ​​to the analyst using the second interval different from the first interval as the analysis interval, thereby preventing the analyst from overlooking abnormalities in the electrocardiogram data.

[0131] The present invention has been described above using embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. For example, all or part of the device can be configured by functionally or physically distributing or integrating any unit. Furthermore, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effects of the new embodiments resulting from the combination also have the effects of the original embodiments. [Explanation of symbols]

[0132] S Electrocardiogram Analysis System 1 electrocardiograph 2. Information terminal 3. Electrocardiogram analyzer 31 Communications Department 32 Storage section 33 Control Unit 331 Acquisition Department 332 Classification Department 333 Reception Department 334 Specific part 335 First Calculation Section 336 Second Calculation Unit 337 Exclusion part 338 Judgment section 339 Output Section

Claims

1. a first calculation unit that calculates a difference between at least two feature points associated with a predetermined wave position in the electrocardiogram data; a second calculation unit that calculates one or more first statistical values ​​of the differences and a second statistical value of the differences different from the first statistical value in specific sections that are sections of a predetermined length and have a start point or an end point respectively at a plurality of reference time points in the electrocardiogram data; an identifying unit that identifies a second section in the electrocardiogram data in which the second statistical value satisfies the determination condition, the second section being a section of the length in the electrocardiogram data, the second section being a section of the length different from the first section within a predetermined range based on the first section, on condition that the second statistical value in a first section in the electrocardiogram data does not satisfy a predetermined determination condition; an output unit that outputs the first statistical value calculated for the first interval in association with the first interval, on condition that the second statistical value for the first interval satisfies the determination condition, and that outputs the first statistical value calculated for the second interval in association with the second interval specified based on the first interval, on condition that the second statistical value for the first interval does not satisfy the determination condition; An electrocardiogram analyzer having:

2. The first section is a second time section having a start point or an end point at each of the plurality of reference time points set with a first time interval in the electrocardiogram data.

2. The electrocardiogram analyzer according to claim 1.

3. The first time period is longer than the second time period.

3. The electrocardiogram analyzer according to claim 2.

4. The second section is a section adjacent to the front or rear of the first section and has the same length as the first section.

4. The electrocardiogram analyzer according to claim 1.

5. the characteristic points are start points, peak points, or end points according to the wave types of each of one or more electrocardiogram waveforms included in the electrocardiogram data; 4. The electrocardiogram analyzer according to claim 1.

6. the second statistical value is the number of differences or the standard deviation of the differences; The determination condition is that the number of the differences is equal to or greater than a predetermined reference value, or that the standard deviation of the differences is equal to or less than a predetermined reference value.

4. The electrocardiogram analyzer according to claim 1.

7. an exclusion unit that determines a range in the electrocardiogram data that satisfies a predetermined exclusion condition as an exclusion range; the second calculation unit calculates the first statistical value of one or more of the differences in a range excluding the exclusion range in the electrocardiogram data.

4. The electrocardiogram analyzer according to claim 1.

8. the output unit causes the information terminal to display the exclusion range and the range excluding the exclusion range in the electrocardiogram data in different display modes.

8. The electrocardiogram analyzer according to claim 7.

9. the exclusion unit determines the first section or the second section as the exclusion range on the condition that at least one of the positions of the feature points, the difference, and a statistical value calculated using the positions of the feature points in the first section or the second section is within a predetermined abnormal range.

8. The electrocardiogram analyzer according to claim 7.

10. the first calculation unit calculates a first difference that is the difference between the two feature points of a first type and a second difference that is the difference between the two feature points of a second type different from the first type; the exclusion unit determines, as the exclusion range, a range in which a relationship between the first difference and the second difference in the electrocardiogram data satisfies a predetermined abnormal condition.

8. The electrocardiogram analyzer according to claim 7.

11. the information terminal to which the output unit outputs the first statistical value further includes a receiving unit that receives, from a user, designation of the first interval or the second interval to be excluded; the exclusion unit determines the first section or the second section designated by the user as the exclusion target as the exclusion range.

8. The electrocardiogram analyzer according to claim 7.

12. the information terminal to which the output unit outputs the first statistical value further includes a receiving unit that receives, from a user, designation of the first interval or the second interval to be displayed; the output unit displays the first interval or the second interval designated by the user as the display target, out of the electrocardiogram data from which the first statistical value is calculated.

4. The electrocardiogram analyzer according to claim 1.

13. the output unit outputs the difference between the first statistical value in the electrocardiogram data acquired from an organism to which a compound has not been administered and the first statistical value in the electrocardiogram data acquired from the organism to which the compound has been administered.

4. The electrocardiogram analyzer according to claim 1.

14. The processor executes calculating a difference between at least two feature points associated with predetermined wave positions in the electrocardiogram data; calculating one or more first statistical values ​​of the differences and second statistical values ​​of the differences different from the first statistical values ​​in specific sections of a predetermined length each having a start point or an end point at each of a plurality of reference time points in the electrocardiogram data; a step of identifying a second section in the electrocardiogram data in which the second statistical value satisfies the determination condition, the second section being a section of the length different from the first section within a predetermined range based on the first section, on the condition that the second statistical value in a first section which is a section of the length in the electrocardiogram data does not satisfy a predetermined determination condition; outputting the first statistical value calculated for the first interval in association with the first interval, on condition that the second statistical value for the first interval satisfies the judgment condition; and outputting the first statistical value calculated for the second interval in association with the second interval specified based on the first interval, on condition that the second statistical value for the first interval does not satisfy the judgment condition; An electrocardiogram analysis method comprising:

15. The processor calculating a difference between at least two feature points associated with predetermined wave positions in the electrocardiogram data; calculating one or more first statistical values ​​of the differences and second statistical values ​​of the differences different from the first statistical values ​​in specific sections of a predetermined length each having a start point or an end point at each of a plurality of reference time points in the electrocardiogram data; a step of identifying a second section in the electrocardiogram data in which the second statistical value satisfies the determination condition, the second section being a section of the length different from the first section within a predetermined range based on the first section, on the condition that the second statistical value in a first section which is a section of the length in the electrocardiogram data does not satisfy a predetermined determination condition; outputting the first statistical value calculated for the first interval in association with the first interval, on condition that the second statistical value for the first interval satisfies the judgment condition; and outputting the first statistical value calculated for the second interval in association with the second interval specified based on the first interval, on condition that the second statistical value for the first interval does not satisfy the judgment condition; A program that executes.

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