Electrocardiogram analysis apparatus

Abstract

To provide an electrocardiogram analyzer capable of providing information specific to electrocardiograms measured over a plurality of days.SOLUTION: An electrocardiogram analysis device acquires electrocardiogram data whose measurement period exceeds 24 hours, and performs trend display for a long-time electrocardiogram for time-series parameter values obtained on the basis of the electrocardiogram data. The trend display for the long-term ECG is a trend display in which time-series parameter values obtained based on the ECG data are presented in a three dimensional graph having axes of a time zone, a date, and a value, and in the three dimensional graph, for each of an axial direction of the time zone and an axial direction of the date, coordinates of parameters plotted adjacent to each other are connected, the value of the parameter is a calculated value, and the coordinates of the parameter are coordinates corresponding to the value of the parameter.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an electrocardiogram analyzer. [Background technology]

[0002] To detect symptoms such as arrhythmia that are difficult to detect with short-term electrocardiogram measurements, long-term electrocardiogram measurements are performed using a Holter monitor. The quality of electrocardiograms measured with a Holter monitor is not consistent and they contain waveforms for 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] As described in Patent Document 1, the maximum measurement time for a typical Holter electrocardiograph is one day (24 hours), but some are capable of measuring for a longer period, for example, several days. However, similar automatic analysis is performed for measurements over multiple days (for example, 48 hours or more) and for measurements over one day, and it cannot be said that sufficient consideration has been given to automatic analysis specific to measurements over multiple days.

[0005] The present invention has been made in view of the above problems of the conventional technology, and in one aspect thereof, provides an electrocardiogram analysis device capable of providing information specific to electrocardiograms measured over multiple days. [Means for solving the problem]

[0006] The above-mentioned object can be achieved by an electrocardiogram analysis device having an acquisition means for acquiring electrocardiogram data with a measurement period exceeding 24 hours, and a control means for performing a trend display for long-term electrocardiograms of time-series parameter values ​​obtained based on the electrocardiogram data, wherein the trend display for long-term electrocardiograms is a trend display that presents the time-series parameter values ​​obtained based on the electrocardiogram data in a three-dimensional graph having axes of time zone, date, and value, and in the three-dimensional graph, the coordinates of adjacently plotted parameters are connected in each of the time zone axis direction and the date axis direction, the parameter values ​​are calculated values, and the parameter coordinates are coordinates corresponding to the parameter values. [Effects of the Invention]

[0007] With this configuration, the present invention can provide an electrocardiogram analysis device and a control method thereof that can provide information specific to electrocardiograms measured over multiple days. [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] FIG. 2 is a diagram showing an example of a two-dimensional graph presented by the electrocardiogram analysis device according to the embodiment. [Figure 3] FIG. 2 is a diagram showing an example of a three-dimensional graph presented by the electrocardiogram analysis apparatus according to the embodiment. [Figure 4] FIG. 10 is a diagram showing another example of a three-dimensional graph presented by the electrocardiogram analysis device 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, we will explain the operation of the electrocardiogram analysis device 100, which is realized by the CPU 1 executing an automatic analysis application. 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 acquire. 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 specified file name).

[0021] The CPU 1 stores the acquired data file in the storage device 10. It should be noted that, instead of acquiring the entire data file all at once, the electrocardiogram data stored in the data file may be acquired in fixed amounts at a time. In this embodiment, the electrocardiogram data is assumed to be digital data that has been A / D converted under predetermined conditions. There are no particular restrictions on the type or number of leads included in the electrocardiogram data; the electrocardiogram data may include one or more leads measured by a general Holter monitor, such as NASA lead, CC5 lead, or CM5 lead, or may include the standard 12 leads. The measurement period for the electrocardiogram data is assumed to be a predetermined time exceeding 24 hours (e.g., 27 hours, 2 days, or one week).

[0022] The CPU 1 first applies a quality check process to the electrocardiogram data to detect poor signal intervals that are unsuitable for analysis. For example, the CPU 1 evaluates the baseline level and superimposed noise, and identifies 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, the CPU 1 applies a quality check process to the data on each channel.

[0023] The CPU 1 applies quality check processing to all data from the start to the end of measurement, and stores information that can identify the detected bad signal intervals (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 following processing to intervals of the electrocardiogram data excluding the bad signal intervals (referred to as analysis intervals or valid signal intervals).

[0024] Next, CPU 1 detects QRS interval candidates from the electrocardiogram data. If multiple channels (leads) are measured using a Holter electrocardiograph, CPU 1 detects QRS interval candidates from the data of each channel. CPU 1 then detects the candidate that is determined to be highly reliable as the final QRS interval. Reliability can be determined based on one or more of the following: signal quality, degree of noise contamination, validity of the RR interval, and whether or not it has been detected in other leads.

[0025] The CPU 1 then calculates a feature (parameter) based on the QRS interval. The calculated parameters include, but are not limited to, the RR interval (RRI) between adjacent QRS intervals, the width of the QRS interval, the height of the QRS interval, the direction of the QRS interval, and the area of ​​the QRS interval. Furthermore, the CPU 1 can calculate other parameters from the parameters based on the QRS interval. In this embodiment, as an example, a parameter related to heart rate variability (HRV) is calculated based on the time-series data of the RRI.

[0026] There are no particular limitations on the types of HRV-related parameters to be calculated, and any known parameters can be calculated. For example, the CPU 1 can calculate frequency domain parameters (e.g., one or more of VLF, LF, HF, LF / HF, CVVLF, CVLF, CVHF, and CVLF / HF) and time domain parameters (e.g., one or more of AVNN, SDNN, CVNN, and RR50(+)).

[0027] For example, the CPU 1 applies a fast Fourier transform (FFT) to the RR curve obtained by spline interpolation of the RRI time series data to obtain a power spectrum. Then, the CPU 1 calculates the power (integral value) for each predetermined frequency band in the power spectrum as VLF, LF, and HF. For example, VLF is the power in the frequency band of 0.0033 to 0.04 Hz, LF is the power in the frequency band of 0.04 to 0.14 Hz, and HF is the power in the frequency band of 0.14 to 0.4 Hz.

[0028] AVNN, SDNN, and CVNN are the average value, standard deviation, and SDNN / AVNN (%) of RRI per 24 hours, respectively. RR50(+) is the number of occurrences per 24 hours of RRI with a difference of more than 50 ms.

[0029] HRV parameters are used to evaluate the autonomic nervous system (sympathetic and parasympathetic nervous systems) and to predict the occurrence of ventricular tachycardia and ventricular fibrillation.

[0030] In addition, in this embodiment, the CPU 1 calculates a day-to-day difference and a parameter based on the day-to-day difference for one or more calculated parameters. As described above, since measurement using a Holter electrocardiogram monitor is generally performed for approximately 24 hours, even for electrocardiograms measured over multiple days, analysis in 24-hour units is simply repeated for the number of days, and evaluation between data measured on different days, such as day-to-day difference, has not been performed.

[0031] When the CPU 1 acquires electrocardiogram data measured over multiple days, it calculates the daily difference of the parameters and parameters based on the daily difference in addition to the previous calculation of the parameters. The daily difference of the parameters is the difference between parameter values ​​corresponding to the same time on consecutive dates. Furthermore, the parameters based on the daily difference may be, for example, the times when the daily difference is maximum and minimum between two consecutive days, or the maximum, minimum, and average values ​​of the daily difference over the entire measurement period, but are not limited to these.

[0032] The CPU 1 stores all the calculated time-series data of parameters and RRI in association with the electrocardiogram data or identification information (such as a file name) of the electrocardiogram data in the storage device 10. In this embodiment, the CPU 1 determines that electrocardiogram data having a measurement period of a predetermined time or more, more than 24 hours, is electrocardiogram data measured over multiple days.

[0033] Day-to-day differences of the same parameter and parameters based on day-to-day differences are information that cannot be obtained through 24-hour measurements and can only be obtained through measurements over multiple days. For example, for HRV-related parameters, it is possible to determine the time of day when the day-to-day difference is greatest and the fluctuations in day-to-day differences depending on the day of the week. This can provide information that is expected to be used in new ways, such as identifying the times and days of the week that each subject should be careful of.

[0034] Furthermore, when the CPU 1 acquires electrocardiogram data measured over multiple days, it calculates the day-to-day difference of the parameters and parameters based on the day-to-day difference in addition to the previous calculation of the parameters, thereby providing the user with information that cannot be obtained by 24-hour measurement but can only be obtained by measurement over multiple days.

[0035] The CPU 1 provides a function for displaying trends that show the time-dependent changes in parameter values ​​over the entire measurement period using a two-dimensional graph with a continuous time axis and a value axis. Furthermore, the CPU 1 provides a trend display function specific to electrocardiogram data measured over multiple days, which displays trends in a three-dimensional graph with a first time axis indicating the time period, a second time axis indicating the date that is perpendicular to the first time axis, and a value axis.

[0036] 2 is a diagram showing an example of a two-dimensional graph 250 presented on the display unit 6 by the trend display function provided by the electrocardiogram analysis device 100. Here, as an example, a two-dimensional graph 250 is shown that provides a trend display of five frequency domain parameters related to HRV.

[0037] The change over time (trend) in the value of each parameter is shown in the form of a two-dimensional graph in which the parameter values ​​are plotted on the horizontal axis representing time and the vertical axis representing value. The parameters to be displayed as trends can be switched by operating pull-down menus 252 and 254. Pull-down menu 252 switches between frequency domain parameters and time domain parameters to be displayed as trends. Pull-down menu 254 is displayed only when a frequency domain parameter is specified in pull-down menu 252, and switches between a parameter based on the power spectrum and its fluctuation coefficient (CCV).

[0038] In response to determining that the measurement period of electrocardiogram data is equal to or longer than a predetermined time exceeding 24 hours, CPU 1 enables the trend display for long-term electrocardiogram and displays long-term trend button 256. When long-term trend button 256 is operated, the display switches to the trend display for long-term electrocardiogram using a three-dimensional graph.

[0039] 3 is a diagram showing an example of a three-dimensional graph 300 presented on the display unit 6 by the electrocardiogram analysis device 100. Here, a three-dimensional graph presenting an HRV-related parameter HF calculated based on electrocardiogram data measured over two weeks (14 days) is shown. However, the user can arbitrarily select the parameters to be presented using the three-dimensional graph.

[0040] The three-dimensional graph 300 has orthogonal X, Y, and Z axes, with parameter values ​​plotted on the Z axis. Furthermore, time periods (time ranges) are plotted on the X axis, and dates are plotted at predetermined equal intervals on the Y axis. Because the time period on the X axis is common to all dates, the change in the parameter value corresponding to any X coordinate along the Y axis represents the daily fluctuation of the parameter value at the time corresponding to the X coordinate.

[0041] In addition, adjacent plotted parameter coordinates are connected by a straight line on both the time axis (X axis) and the date axis (Y axis). The slope of this line allows intuitive understanding of changes over time within the same day and over the course of a day.

[0042] In addition, parameter values ​​are divided into multiple levels (ranges) based on the maximum value for the entire measurement period, and each parameter value range is displayed in a different color, allowing users to intuitively grasp the trends in the dates and times when large and small values ​​are obtained.

[0043] 3 shows a line-shaped cursor 310 that highlights the parameter value corresponding to a particular X coordinate (i.e., time) in the three-dimensional graph 300 and the line connecting the parameter values. In FIG. 2, the cursor 310 highlights the parameter value corresponding to 7:00 AM on each day from April 1 to April 14, which is the measurement period.

[0044] The X coordinate for displaying cursor 310 can be determined in response to an operation to specify a point in the graph. Alternatively, the X coordinate may be determined in response to a time specified through operation unit 8. Cursor 310 can also be moved in the X-axis direction by operating operation unit 8 (for example, by pressing a direction key). Cursor 310 makes it easier to grasp the daily difference in parameter value corresponding to a specific time within the measurement period.

[0045] Furthermore, for the parameter values ​​for multiple days corresponding to the time when cursor 310 is displayed, electrocardiogram analysis device 100 detects the day on which the maximum (Max) and minimum (Min) values ​​were obtained and the day on which the difference between the parameter value of the previous day is the largest. Then, electrocardiogram analysis device 100 displays indicators for the maximum (Max), minimum (Min), and maximum difference (MaxΔ) values ​​of the parameters near the plot positions of the corresponding parameter values. As shown in FIG. 2, lines connecting the indicators to the positions on cursor 310 may be displayed to clearly indicate the plot positions indicated by the indicators.

[0046] Furthermore, the electrocardiogram analysis device 100 changes the display magnification (scale) and viewpoint of the three-dimensional graph 300 in response to an operation of the operation unit 8. Therefore, the user can observe the three-dimensional graph 300 at any magnification and viewpoint that allows the user to easily view the daily difference in the parameter value at a desired time.

[0047] A trend display using a three-dimensional graph can be displayed simultaneously for multiple parameters. FIG. 4 is a diagram showing an example of a screen 400 that displays trend displays of four parameters in a comparable manner using three-dimensional graphs. The type of parameter presented in each three-dimensional graph can be set and changed by operating a pull-down menu 410 via the operation unit 8. When the electrocardiogram analysis device 100 detects an operation to change the display magnification and viewpoint for one of the four three-dimensional graphs included in the screen 400, it changes or does not change the display magnification and viewpoint for the other three three-dimensional graphs in conjunction with the operation, depending on the settings.

[0048] As described above, according to this embodiment, an electrocardiogram analysis device can be realized that can provide the user with unique and useful information from electrocardiogram data measured over multiple days that cannot be obtained by measurement within 24 hours.

[0049] (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]

[0050] 100... general-purpose computer (electrocardiogram analyzer), 1... CPU, 4... memory card, 10... storage device, 200... external device

Claims

1. an acquisition means for acquiring electrocardiogram data having a measurement period exceeding 24 hours; and a control means for displaying a trend of a long-term electrocardiogram for time-series parameter values ​​obtained based on the electrocardiogram data, the trend display for the long-term electrocardiogram presents the time-series parameter values ​​obtained based on the electrocardiogram data in a three-dimensional graph having axes of time zone, date, and value, In the three-dimensional graph, the coordinates of adjacently plotted parameters are connected along the time zone axis and the date axis, the values ​​of the parameters are calculated values, and the coordinates of the parameters are coordinates corresponding to the values ​​of the parameters.

2. 2. The electrocardiogram analyzer according to claim 1, wherein the parameter is a day-to-day difference or is based on a day-to-day difference.

3. 3. The electrocardiogram analyzer according to claim 1, wherein the coordinates of the parameters plotted adjacently in the date axis direction correspond to the parameter values ​​corresponding to the same time.

4. an acquisition means for acquiring electrocardiogram data having a measurement period exceeding 24 hours; and a control means for displaying a trend of a long-term electrocardiogram for time-series parameter values ​​obtained based on the electrocardiogram data, the trend display for the long-term electrocardiogram presents the time-series parameter values ​​obtained based on the electrocardiogram data in a three-dimensional graph having axes of time zone, date, and value, An electrocardiogram analysis device further comprising: a cursor extending in the date axis direction along the three-dimensional graph and movable in the time zone axis direction;

5. 5. The electrocardiogram analyzer according to claim 4, wherein the cursor is linear.

6. 6. The electrocardiogram analyzer according to claim 5, wherein the time indicated by the cursor is displayed together with the cursor.

7. 7. The electrocardiogram analyzer according to claim 5, further comprising an indicator indicating the magnitude of the difference between the value of the parameter at the time indicated by the cursor and the value of the previous day, and the ....

8. 8. The electrocardiogram analyzer according to claim 1, wherein the parameter is a parameter related to heart rate variability (HRV).

9. 9. The electrocardiogram analyzer according to claim 1, wherein the three-dimensional graphs for each of a plurality of parameters can be displayed in a comparable manner.

10. 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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