Electrocardiogram analyzer and control method thereof

Abstract

To provide an electrocardiogram analyzer capable of providing a function to assist diagnosis of arrhythmia, and a control method for the same.SOLUTION: An electrocardiogram analyzer has a function to generate synthetic electrocardiogram data related to induction that is not included in electrocardiogram data from the electrocardiogram data related to a plurality of inductions. The electrocardiogram analyzer outputs a trend display screen showing changes over time of a predetermined feature parameter with respect to induction included in the electrocardiogram data and induction included in the synthetic electrocardiogram data.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an electrocardiogram analyzer and a control method thereof. [Background technology]

[0002] To detect symptoms such as arrhythmia that are difficult to detect with short-term electrocardiogram measurements, long-term (typically 24 hours) electrocardiogram measurements are performed using a Holter monitor. The quality of electrocardiograms measured with a Holter monitor is not consistent and they contain waveforms representing tens of thousands of beats. Therefore, it is common for technicians and doctors to perform various analyses based on the results of automatic analysis by an electrocardiogram analyzer (Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-95552 [Patent Document 2] Japanese Patent Publication No. 2020-130335 Summary of the Invention [Problem to be solved by the invention]

[0004] Long-term electrocardiograms are effective in diagnosing arrhythmias such as ischemic heart disease. For accurate diagnosis, it is desirable to measure electrocardiograms using the standard 12-lead system or more. However, in order to reduce the burden on subjects during daily life, only a small number of Holter monitors are capable of measuring the standard 12-lead system, and most monitors measure electrocardiograms using two or three leads.

[0005] The present invention has been made in view of the above problems in the prior art, and in one aspect thereof, provides an electrocardiogram analyzer capable of providing a function for assisting in the diagnosis of arrhythmia, and a control method thereof. [Means for solving the problem]

[0006] The above object is to provide a method for obtaining electrocardiogram data relating to a plurality of leads, a generating means for generating, from the electrocardiogram data, composite electrocardiogram data relating to leads not included in the electrocardiogram data, and an output means for outputting a trend display screen showing time-dependent changes in predetermined characteristic parameters for the leads included in the electrocardiogram data and the leads included in the composite electrocardiogram data. ,of Yes the trend display screen has a configuration in which values ​​of predetermined characteristic parameters are plotted in a two-dimensional area having a time axis, and in response to detection of a first operation on the two-dimensional area, the generating means generates composite electrocardiogram data for a predetermined period based on a time corresponding to the operation position, and the output means reflects the predetermined characteristic parameters based on the composite electrocardiogram data on the trend display screen. This is achieved by an electrocardiogram analysis device characterized by the above. [Effects of the Invention]

[0007] With this configuration, the present invention can provide an electrocardiogram analyzer capable of providing a function for assisting in the diagnosis of arrhythmia, and a control method thereof. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a block diagram illustrating an example of the functional configuration of a general-purpose computer as an example of an electrocardiogram analysis apparatus according to an embodiment of the present invention. [Figure 2] 4 is a flowchart illustrating the operation of the electrocardiogram analysis apparatus according to the embodiment. [Figure 3] FIG. 10 is a diagram showing an example of a screen presented by the electrocardiogram analysis apparatus according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention will be described in detail below based on exemplary embodiments with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the claimed invention. Furthermore, although multiple features are described in the embodiments, not all of them are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0010] In the following embodiments, the present invention will be described with reference to a general-purpose computer such as a personal computer or a tablet terminal, but the present invention can also be implemented in any electronic device, such as a media player, a smartphone, or a game console.

[0011] 1 is a block diagram showing an example of the functional configuration of a general-purpose computer 100 capable of functioning as an electrocardiogram analysis device according to this embodiment. A CPU 1 functioning as a control unit implements functions according to the program by, for example, reading a program stored in a storage device 10 into a RAM 3 and executing the program. For example, by executing a specific application program (electrocardiogram analysis application) while the operating system (OS) is running on the general-purpose computer 100, the general-purpose computer 100 functions as the electrocardiogram analysis device according to this embodiment.

[0012] The storage device 10 is, for example, a hard disk drive (HDD) or a solid state drive (SSD), and stores operating system (OS), device drivers, applications, user data, etc. The storage device 10 also stores GUI (Graphical User Interface) data for displaying menu screens, user setting data, initial setting data for applications, etc.

[0013] ROM2 stores programs, firmware, and various setting information required for starting up the computer, such as a bootstrap loader. At least a portion of ROM2 may be rewritable.

[0014] The RAM 3 is used as an area for expanding the programs executed by the CPU 1 and as a temporary storage area for variables, data, etc. Furthermore, part of the RAM 3 may be used as a video memory.

[0015] The memory card 4 is a recording medium that can be inserted into the card slot 5 and removed from the card slot 5. The general-purpose computer 100 can read data from the memory card 4 inserted into the card slot 5 and write data to the memory card 4. In this embodiment, the general-purpose computer 100 acquires data such as a long-term electrocardiogram recorded by a Holter electrocardiograph through the memory card 4. Note that the general-purpose computer 100 may acquire the electrocardiogram data to be automatically analyzed by other methods. For example, the electrocardiogram data to be automatically analyzed may be acquired from the Holter electrocardiograph that performed the measurement or from another external device 200 that stores the measured electrocardiogram data, by communication via a communication interface 20 (described later).

[0016] The display unit 6 includes a display device such as a liquid crystal display (LCD) or an organic EL display, a display control circuit, etc. Although Fig. 1 shows a configuration in which the display unit 6 is built into the general-purpose computer 100, the display unit 6 may be external. Also, both a built-in display unit 6 and an external display unit 6 may be included.

[0017] The operation unit 8 is a device with which the user inputs instructions to the general-purpose computer 100, and is typically one or more input devices such as a keyboard, a pointing device (such as a mouse), or a contact-sensing device (such as a touch panel). The keyboard may be a hardware keyboard or a software keyboard. The touch panel may be provided on the display unit 6, or may be in the form of a touchpad, such as those commonly found on notebook computers.

[0018] The communication interface (I / F) 20 is hardware that enables the general-purpose computer 100 to communicate with the external device 200 in accordance with a predetermined standard. The communication I / F 20 has a configuration according to the communication standard it supports, such as a connector that complies with a wired communication standard and a wireless transmitter / receiver that complies with a wireless communication standard. The communication I / F 20 may support multiple communication standards. There are no particular restrictions on the communication standards that the communication I / F 20 supports, but typical examples of wired communication standards include Ethernet (registered trademark) and USB, and typical examples of wireless communication standards include Bluetooth (registered trademark) and wireless LAN (IEEE802.11x).

[0019] A user (e.g., a technician) who uses automatic analysis of an electrocardiogram measured by a Holter electrocardiograph starts the automatic analysis application stored in storage device 10 by an operation method corresponding to the OS running on general-purpose computer 100. CPU 1 reads the automatic analysis application from storage device 10 into RAM 3 and executes it, causing general-purpose computer 100 to function as an electrocardiogram analyzer. Hereinafter, general-purpose computer 100 functioning as an electrocardiogram analyzer will be referred to as electrocardiogram analyzer 100.

[0020] Next, the operation of the electrocardiogram analyzer 100, which is realized by the CPU 1 executing the automatic analysis application, will be described using the flowchart shown in Fig. 2. Here, the operation for implementing trend display, which visually presents changes over time in characteristic parameters of an electrocardiogram, will be described as an example of a function for assisting in the diagnosis of arrhythmia.

[0021] In S201, the CPU 1 acquires a data file storing electrocardiogram data to be automatically analyzed in response to an operation from the operation unit 8. The CPU 1 may, for example, present a file browser screen provided by the OS on the display unit 6, and allow the user to specify the data file to be acquired. Alternatively, the CPU 1 may search a predetermined location such as the memory card 4, and automatically acquire a data file that meets predetermined conditions (for example, a data file with a predetermined file name).

[0022] The CPU 1 stores the acquired data file in the storage device 10. Instead of acquiring the entire data file all at once, the electrocardiogram data stored in the data file may be acquired in fixed amounts. In this embodiment, the electrocardiogram data is assumed to be digital data that has been A / D converted under predetermined conditions. The electrocardiogram data includes the types and number of leads from which X, Y, and Z leads can be derived. For example, the electrocardiogram data may be three leads, eV1, eV5, and eVF, or a standard 12-lead system, but is not limited to these. Here, the electrocardiogram data is assumed to be based on the standard 12-lead system. The measurement period for the electrocardiogram data is assumed to be 24 hours, but may exceed 24 hours. If the measurement period is practical for use in diagnosing arrhythmia, the measurement period may be less than 24 hours.

[0023] In S203, CPU 1 applies preprocessing to the electrocardiogram data. The preprocessing may be a quality check process that detects poor signal intervals unsuitable for analysis from the electrocardiogram data. In the quality check process, CPU 1 evaluates, for example, the baseline level and superimposed noise, and determines intervals where the superimposed level exceeds a threshold or noise intervals as poor signal intervals and excludes them from the analysis process. When measurements are taken on multiple channels (leads) using a Holter electrocardiograph, CPU 1 applies preprocessing to the data on each channel.

[0024] The CPU 1 applies preprocessing to all data from the start to the end of measurement, and stores information that can identify the detected bad signal interval (e.g., the start date and time and the end date and time of the interval) in association with identification information for the data file (e.g., the file name) in the storage device 10. The CPU 1 applies the subsequent processing to intervals of the electrocardiogram data excluding the bad signal intervals (referred to as analysis intervals or valid signal intervals).

[0025] In S205, the CPU 1 generates a composite waveform by waveform synthesis processing. The waveform synthesis processing is a process for generating composite electrocardiogram data (synthetic waveform) relating to leads that have not been measured based on actually measured electrocardiogram data. The waveform synthesis processing makes it possible to obtain composite electrocardiogram data that would have been measured at a position on the body surface where no electrodes were attached at the time of measurement.

[0026] Waveform synthesis processing allows for the acquisition of electrocardiogram data for a greater number of leads than is possible during measurement, thereby supporting the diagnosis of arrhythmia without increasing the burden on the subject during measurement. For example, if standard 12-lead electrocardiogram data is measured, generating synthesized electrocardiogram data for one or more of leads V3R-V6R and V7-V9 allows for a wider range of cardiac potential activity to be observed. Note that the V6R lead is less clinically necessary than the V3R-V5R leads, so synthesis is not necessary. Similarly, if three-lead electrocardiogram data (leads eV1, eV5, and eVF) are measured, synthesized electrocardiogram data for one or more of the standard 12 leads can be generated.

[0027] A composite waveform of leads at a certain position (virtual electrode position) on the body surface can be generated by a known method. For example, the CPU 1 generates electrocardiogram data for leads X, Y, and Z from actually measured electrocardiogram data. Then, the CPU 1 generates composite electrocardiogram data for leads at the virtual electrode position by calculating the dot product of the electrocardiogram data for leads X, Y, and Z and the x, y, and z components of the lead vector at the virtual electrode position for each sample of the electrocardiogram data. For specific examples of waveform synthesis processing, see, for example, Japanese Patent Nos. 4664068 and 4955153.

[0028] Since the present embodiment is directed to a long-term electrocardiogram, generating composite electrocardiogram data over the entire measurement period requires a considerable amount of processing time. Although it depends on the number of leads for generating the composite electrocardiogram data and the processing capacity of the electrocardiogram analysis device 100, generating 24 hours' worth of composite electrocardiogram data for all of leads V3R to V5R and V7 to V9 based on 12-lead electrocardiogram data may require, for example, several tens of minutes.

[0029] For example, when automatic analysis processing needs to be performed quickly, such as when performing automatic analysis processing on electrocardiogram data for a large number of subjects, it is not realistic to wait several tens of minutes for waveform synthesis processing after each automatic analysis processing. Therefore, the electrocardiogram analysis device 100 of this embodiment can generate composite electrocardiogram data for multiple discrete periods within the electrocardiogram data measurement period. For example, the CPU 1 can generate composite electrocardiogram data for a fixed period of time, for example, one minute to one second from the start of the measurement period (between valid signal devices), and then generate composite electrocardiogram data for a fixed period at regular intervals of one hour to 15 minutes.

[0030] In this way, by generating composite electrocardiogram data for a plurality of discrete periods within the measurement period of electrocardiogram data, the time required for waveform synthesis processing can be significantly reduced. The cycle and length of the period for performing waveform synthesis processing can be determined by taking into consideration the disadvantage of the time resolution of the information obtained from the composite electrocardiogram data being lower than the time resolution of the information obtained from the measured electrocardiogram data and the advantage of reducing the processing time.

[0031] In S207, the CPU 1 calculates predetermined characteristic parameters for both the measured electrocardiogram data and the composite electrocardiogram data. Any characteristic parameter whose time-dependent change can be observed can be calculated. Examples of the calculated characteristic parameters include, but are not limited to, the heart rate (HR) and its variability (HRV) per beat, and the level of the ST segment relative to a reference level.

[0032] The CPU 1 divides the electrocardiogram data for each lead for which the characteristic parameters are calculated into one heartbeat and detects the QRS interval. For example, the CPU 1 detects QRS interval candidates based on the signal level, and selects the candidate determined to be highly reliable as the final QRS interval. The reliability can be determined based on one or more of the signal quality, the degree of noise contamination, the validity of the RR interval, and whether or not the QRS interval has been detected in other leads.

[0033] The CPU 1 can then calculate characteristic parameters based on the detected QRS interval. For example, HR and HRV can be calculated from the RR interval (RRI) of adjacent QRS intervals. Furthermore, the CPU 1 detects the ST interval based on the detected QRS interval, and calculates the signal level (minimum, maximum, or average) of the ST interval when the reference level is set to 0. The reference level may be, for example, a baseline level (e.g., the level of the P wave onset). The CPU 1 stores the calculated characteristic parameters in the storage device 10, for example, for each lead.

[0034] In S209, the CPU 1 outputs the trend display screen to the display unit 6. The CPU 1 may output the trend display screen in response to a user instruction via a GUI provided by the electrocardiogram analysis application. The CPU 1 may output the trend display screen to an external display device or printer, or may output it as a data file.

[0035] FIG. 3(a) shows an example of a trend display screen 300. The trend display screen 300 has a configuration in which the values ​​of characteristic parameters are plotted in a two-dimensional area having a time axis. In this example, the two-dimensional area is a rectangular area having a horizontal axis and a vertical axis, with time assigned to the horizontal axis and values ​​assigned to the vertical axis, but the elements assigned to the axes may be reversed. The length of the period assigned to the time axis can be changed using a pull-down menu 326. In FIG. 3(a), 27 hours are specified, and since the measurement period is 24 hours, values ​​are not plotted for the last 3 hours.

[0036] 3(a), the trends of HR 310 and ST level 312 are displayed as feature parameters calculated from electrocardiogram data. The CPU 1 reads out feature parameters according to the settings from the storage device 10, generates data for a trend display screen 300, and stores the data in the video memory area of ​​the RAM 3, thereby displaying the trend display screen 300 on the display unit 6.

[0037] The scroll bar 314 is enabled when the trend for the entire measurement period cannot be displayed in the two-dimensional area. The CPU 1 scrolls the display content horizontally in response to operation of the scroll bar 314. Furthermore, when the CPU 1 detects operation of the first button 320 or the last button 322, it displays the trend for the range including the beginning and end of the measurement period.

[0038] When the CPU 1 detects operation of the remeasurement button 318, it recalculates the characteristic parameters for the previous measurement period and reflects the results on the trend display screen 300. The lead selection pull-down menu 324 is a means for switching the leads to be displayed for the characteristic parameters calculated for each lead. When there are standard 12 leads and composite 6 leads (V3R-V5R and V7-V9), it is possible to switch between sets of 3 leads: "I-III," "aVR-aVF," "V1-V3," "V4-V6," "S-V3R-S-V5R," and "S-V7-S-V9." Here, "S-" in the lead name indicates a composite lead.

[0039] Note that if waveform synthesis processing is performed only for discrete periods, the time resolution of the feature parameters based on the synthesized electrocardiogram data will be lower than the time resolution of the feature parameters based on the measured electrocardiogram data. Therefore, in the trend display of the feature parameters based on the synthesized electrocardiogram data, adjacent plots of parameter values ​​can be connected by a line to make it easier to grasp the trend of time change of the parameter values.

[0040] 3(a), based on information about acceleration and posture measured together with the electrocardiogram, displays (Acc, Pos, Act) showing the subject's body position and activity state are included in the trend display screen 300. 316 indicates the period during which the subject was determined to be asleep.

[0041] Next, operations in response to operations within the two-dimensional region will be described. Fig. 3(b) shows an enlarged portion of the ST level trend based on the composite electrocardiogram data. For example, by selecting a shorter time using the pull-down menu 326, the display magnification in the time axis direction can be increased. Trends related to other parameters such as HR are not shown for convenience.

[0042] When CPU 1 detects a position designation operation within the two-dimensional area, it displays cursor 328 indicating the time corresponding to the designated position, and also displays a pop-up menu near cursor 328. The position designation operation may be, for example, a mouse click while the mouse cursor is within the two-dimensional area, a tap operation on the screen, or the like.

[0043] The pop-up menu includes selectable commands. In this example, the pop-up menu includes command 330 to generate additional composite ECG data when composite ECG data has only been generated for a discrete period, and command 332 to display all lead waveforms, including the composite waveform. Note that command 330 does not necessarily have to be included when composite ECG data has been generated for the entire period for which the trend is displayed.

[0044] When an operation to select command 330 is detected, CPU 1 generates composite electrocardiogram data for a predetermined period based on the time corresponding to the operation position (for example, a certain period centered on cursor 328). Then, CPU 1 calculates a characteristic parameter (here, ST level) based on the newly generated composite electrocardiogram data and reflects it in the trend display.

[0045] On the other hand, when an operation to select command 332 is detected, CPU 1 displays a waveform display screen (FIG. 3(c)) that displays a list of average waveforms for each lead of electrocardiogram data (including composite electrocardiogram data) included in a certain period centered on cursor 328. In FIG. 3(c) showing an example of waveform display screen 350, the four columns from the left are average waveforms for the standard 12 leads, and the remaining two columns are average waveforms for the composite 6 leads. ST levels are also displayed below the lead names.

[0046] Returning to the explanation of Figure 2, in S211, the CPU 1 determines whether or not a user operation of the operation unit 8 has been detected while the trend display screen 300 is being displayed, and if it is determined that a user operation has been detected, it executes S231, and if it is not determined that a user operation has been detected, it repeatedly executes S211.

[0047] In S213 and S217, the CPU 1 determines whether the detected operation is a specific operation within the two-dimensional area. Here, the specific operations are assumed to be a first operation (selection operation of command 330) instructing the addition of a measurement point and a second operation (selection of command 332) instructing the display of a list of waveforms. If it is determined that an operation instructing the addition of a measurement point has been detected, the CPU 1 executes S215, and if it is determined that an operation instructing the display of a list of waveforms has been detected, the CPU 1 executes S219. If another operation is detected, the CPU 1 executes an operation corresponding to the operation, such as the operation described with reference to FIG. 3, and then executes S211 again.

[0048] In S215, the CPU 1 generates composite electrocardiogram data for a predetermined period based on the time corresponding to the operation position (for example, one beat or one second or more including the time corresponding to the operation position), as described with reference to Fig. 3(b). Thereafter, the CPU 1 executes S207 and S209 to reflect the feature parameters based on the additionally generated composite electrocardiogram data in the trend display.

[0049] In S219, the CPU 1 displays a waveform list display screen as shown in Fig. 3(c) based on the electrocardiogram data for a predetermined period based on the time corresponding to the operation position, and then executes S211.

[0050] As described above, the electrocardiogram analysis device of this embodiment has a function of providing, for example, time changes in feature parameters based on electrocardiogram data, time changes in feature parameters for leads that are not measured, based on synthetic electrocardiogram data, thereby supporting accurate arrhythmia diagnosis without increasing the burden on the subject when measuring an electrocardiogram over a long period of time.

[0051] Furthermore, the electrocardiogram analysis device of this embodiment can generate composite electrocardiogram data for multiple discrete periods instead of generating composite electrocardiogram data over the entire long measurement period. This prevents the processing time required to generate the composite electrocardiogram data from reducing diagnostic work efficiency. Furthermore, even for periods for which composite electrocardiogram data has not been generated, the device generates composite electrocardiogram data in response to a user instruction and reflects the data in the display of time-varying feature parameters, making the device easy to use.

[0052] (Other embodiments) The present invention can also be implemented as a program that causes a computer to function as the electrocardiogram analyzer described in the above embodiment. Furthermore, the present invention is not limited to the content of the above embodiment, and various changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, the following claims are appended to clarify the scope of the invention. [Explanation of symbols]

[0053] 100... general-purpose computer (electrocardiogram analyzer), 1... CPU, 4... memory card, 10... storage device, 200... external device

Claims

1. acquiring means for acquiring electrocardiogram data relating to a plurality of leads; generating means for generating synthetic electrocardiogram data relating to leads not included in the electrocardiogram data from the electrocardiogram data; output means for outputting a trend display screen showing time-dependent changes in predetermined characteristic parameters for leads included in the electrocardiogram data and leads included in the composite electrocardiogram data; the trend display screen has a configuration in which values ​​of the predetermined characteristic parameters are plotted in a two-dimensional area having a time axis, In response to detecting a first operation on the two-dimensional area, the generating means generates the composite electrocardiogram data for a predetermined period based on a time corresponding to an operation position; the output means reflects the predetermined characteristic parameters based on the composite electrocardiogram data on the trend display screen. An electrocardiogram analysis device characterized by:

2. 2. The electrocardiogram analyzer according to claim 1, wherein the generating means generates synthetic electrocardiogram data relating to one or more of leads V3R to V6R and V7 to V9, or one or more of standard 12 leads.

3. 3. The electrocardiogram analyzer according to claim 1, wherein the electrocardiogram data is electrocardiogram data measured by a Holter electrocardiograph.

4. 3. The electrocardiogram analyzer according to claim 1, wherein the plurality of leads are standard 12 leads, and the generating means generates composite electrocardiogram data relating to leads V3R to V5R and leads V7 to V9.

5. 5. The electrocardiogram analyzer according to claim 1, wherein the generating means generates the composite electrocardiogram data for a plurality of discrete periods within a measurement period of the electrocardiogram data.

6. An electrocardiogram analysis device as described in any one of claims 1 to 5, characterized in that the trend display screen includes a display showing the subject's posture or activity information.

7. the trend display screen has a configuration in which values ​​of the predetermined characteristic parameters are plotted in a two-dimensional area having a time axis, In response to the detection of a second operation on the two-dimensional area, the output means outputs a screen displaying lead waveforms for a predetermined period based on a time corresponding to the operation position.

7. The electrocardiogram analyzer according to claim 1, wherein the electrocardiogram analyzer is a computer.

8. 8. The electrocardiogram analysis device according to claim 7, wherein, if the composite electrocardiogram data has not been generated for the predetermined period, the generating means generates the composite electrocardiogram data for the predetermined period.

9. 9. The electrocardiogram analyzer according to claim 1, wherein the predetermined characteristic parameter is a parameter related to the level of the ST segment.

10. an acquiring step of acquiring electrocardiogram data relating to a plurality of leads; a generating step of generating synthetic electrocardiogram data relating to leads not included in the electrocardiogram data from the electrocardiogram data; an output step of outputting a trend display screen showing time-dependent changes in predetermined characteristic parameters for leads included in the electrocardiogram data and leads included in the composite electrocardiogram data, the trend display screen has a configuration in which values ​​of the predetermined characteristic parameters are plotted in a two-dimensional area having a time axis, The generating step includes: generating the composite electrocardiogram data for a predetermined period based on a time corresponding to a position of the operation in response to detection of a first operation on the two-dimensional area; The output step includes: reflecting, on the trend display screen, the predetermined characteristic parameter based on the composite electrocardiogram data generated in response to detection of a first operation on the two-dimensional area. A method for controlling an electrocardiogram analyzer.

11. A program for causing a computer to function as each of the means included in the electrocardiogram analyzer according to any one of claims 1 to 9.

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