JPH062127B2 - Cardiac diagnostic device based on exercise load - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention detects an electrocardiogram signal to detect a heart rate (HR) and ST in a state where an exercise load is applied to a subject by a treadmill, an ergometer, or the like. The present invention relates to a heart diagnostic apparatus by exercise load for diagnosing myocardial ischemia and the like based on a relationship with a level.

[Conventional technology]

BACKGROUND ART Conventionally, in order to diagnose myocardial ischemia, diagnostic methods using myocardial scintillation, examination with a cardiac catheter, ST level of electrocardiogram waveform, etc. are well known. Among these, the ST level method using an electrocardiograph can be performed non-invasively by analyzing an electrocardiogram signal while continuing exercise load. Therefore, the ST level / HR against the exercise load has been conventionally used.
Various methods are known in the literature for diagnosing myocardial ischemia with respect to myocardial work by calculating the slope of a plot curve.

[Problems to be Solved by the Invention]

However, in the case of such a method, the subjective result is added, or the result varies greatly depending on the set point of the slope start, and its automatic setting is difficult, and the diagnostic result is automatically applied as a clinical application. There was no device designed to automatically output.

Therefore, the applicant of the present invention, by Japanese Patent Application No. 63-68256, provides a complete correspondence between the plot curve of the ST level decrease rate and the heart rate increase rate when correlating the heart rate increase with the exercise load and the ST level decrease. Focusing on the fact that the size of the area beyond the existing reference line has a peculiar relationship with myocardial ischemia, we proposed a cardiac diagnostic device by exercise load that automatically outputs that area value as a diagnostic index. . As a result, the diagnostic index for the myocardium can be automatically output immediately after a single exercise load without being invasive.

In addition to the method of diagnosing based on the area of the portion exceeding the reference line, the present invention automatically detects the ST level / HR inclination value as an index, thereby improving the diagnostic accuracy of the exercise load. An object of the present invention is to provide a heart diagnostic apparatus according to the present invention.

[Means for Solving the Problems]

In order to achieve this object, the present invention provides a constant ST level / HR plot curve under an exercise load condition for a large number of plot data groups in which one data item is added from the load end point to the load start point. It is configured as shown in FIG. 1 after obtaining a regression line having a correlation coefficient or more and confirming that the largest slope thereof can be effectively used as a diagnostic index.

That is, ST level detection means 2 for detecting the ST levels of the electrocardiogram signals of a plurality of types of leads detected by the electrocardiogram signal detection unit 1 for the subject subjected to exercise, and heartbeat signals from the detected electrocardiogram signals. The heart rate detecting means 3 for deriving and detecting the heart rate per unit time, and the heart rate as one coordinate axis of the Cartesian coordinates and the ST level as the other coordinate axis are detected at predetermined time intervals from a predetermined time point when the load starts. The first plot data creating means 4 for creating the first plot data in which the ST level is plotted with respect to the selected heart rate for each lead, and the predetermined number of the first plot data traced back from the load end time to the predetermined time. Predetermined correlation coefficient for each of a plurality of data groups in which the number of data is increased by sequentially adding the first plot data from the data group to a predetermined time point. The slope value calculating means 5 for calculating the slope value of the above regression line, and the slope specifying means 6 for specifying the maximum slope value among the slope values of all types of guidance and the type of guidance to which this maximum slope value belongs are specified. ST level difference detecting means 7 for detecting the ST level difference with respect to the ST level detected at a predetermined time point of the induction at predetermined time intervals, and the heart rate difference with respect to the heart rate detected at the predetermined time point for each predetermined time interval. Heart rate difference detection means 8 and the heart rate difference as one of the coordinate axes of the Cartesian coordinates, the heart rate difference at a predetermined time point is 0%, the heart rate difference at the end of the load is 100%, and the ST level difference is As the other coordinate axis, the ST level difference at a predetermined time is set to 0.
%, The ST level difference at the end of the load is set as a coordinate value of 100%, and second plot data of the% value of the ST level difference with respect to the detection time point of the% value of the heart rate difference is created for at least the specified lead. Plot data creation means 9
And output means 1 for displaying the second plot data on the plane of the orthogonal coordinate axes and outputting the diagnostic index corresponding to the maximum inclination value.
It was composed of 0 and 11.

The electrocardiogram signal detection unit 1 may be built in the device itself,
Alternatively, the electrocardiogram signal is introduced from the output terminal of a separate general-purpose electrocardiograph by providing only the input terminal without including it in the device configuration.

[Action]

When a signal indicating a predetermined time point when the load starts is input, S
The T level detecting means 2 detects the ST levels of the multi-lead electrocardiographic signals, and the heart rate detecting means 3 detects the heart rate. Then, as shown in FIG. 2, the first plot data creating means 4 uses the heart rate as one coordinate axis of the Cartesian coordinates and the ST level as the other coordinate axis at predetermined time intervals from a predetermined time point when the load starts. First plot data in which the ST level is plotted against the detected heart rate is created for each lead.

At the end of the load, the slope value calculating means 5 determines the data group in a predetermined range from the end of the load of each guidance to the start of the load.
Slope values of the highly correlated ones of the regression lines S ₁ , S ₂ , S ₃ , ... Sn of D _e1 , D _e2 , D _e3 , ... D _en are calculated. Next, the inclination identifying means 6 uses the data groups D _e1 , D _e2 , D of all types of guidance.
Specify the maximum slope value in _e3 , ... D _en and its induction type.

Furthermore, for at least the identified guidance, both difference detection means 7 and 8 detect the ST level difference and the heart rate difference at predetermined time intervals using the ST level and the heart rate at a predetermined time point when the load starts as a reference value. To do. Next, the second plot data creation means 9 sets the heart rate difference and the ST level difference input at the end of the load as 100%, and determines the% value of the ST level difference with respect to the detection point of the% value of the heart rate difference on the orthogonal coordinate plane. The correlation data of the ST level decrease rate with respect to the heart rate increase rate is plotted.

As a result, the output means 10 outputs the maximum slope value of the ST level / HR curve as a diagnostic index, and the output means 11 outputs the second value.
The plot data curve of is displayed on the Cartesian coordinate plane.

〔Example〕

FIG. 3 shows an apparatus for diagnosing heart by exercise load according to an embodiment of the present invention.

In the figure, reference numeral 11 is an electrocardiograph as a 12-lead electrocardiogram signal detection unit attached to a multi-stage load type treadmill whose load increases every 3 minutes. Reference numeral 12 is an electrocardiographic signal processing microcomputer which constitutes the ST level detecting means 2 and the heart rate detecting means 3 of FIG. This microcomputer uses the S of the electrocardiogram signal waveform of each lead to be input.
The T-wave portion is waveform-analyzed and derived by a known method, and its level is detected. Similarly, the number of beats of the heartbeat signal derived by a well-known method for a predetermined time is counted as the number of heartbeats.

Reference numeral 13 denotes the first plot data creating means 4, the slope value calculating means 5, the slope identifying means 6, the ST level difference detecting means 7, the heart rate difference detecting means 8 and the second plot data creating means 9 in FIG. A microcomputer for diagnostic data creation including a CPU that operates according to a program and fixed data stored in a ROM, a RAM that stores processed data, and the like as configured.

In response to an exercise load start signal generated by manual operation of the switch 16, this CPU fetches the ST level and heart rate of each lead at a predetermined time interval defined by the timer 17, for example, every 15 seconds, and stores them in the RAM. , ST level / HR plot data is created every 15 seconds with the heart rate as the horizontal axis of the Cartesian coordinates and the ST level as the vertical axis. Then, about 6 pieces that do not cause a detection error from the load end point to the load start point, that is, a data group of plot data within a time period traced back 2 minutes (which can correspond to D _e1 in FIG. 2) and one piece With respect to the data group (D _e2 ...... D _en , where n is the data at the load starting point) for the remaining number of plot data that is increased by increasing the number of data, the correlation coefficient 0.
The slope value is calculated for 12 leads when 85 or more regression lines are detected. Then, the largest gradient value in the data group of each guidance is detected, and the maximum gradient value among the largest gradient values of all types of guidance and the type of the guidance are specified. If the correlation coefficient is too high, the regression line may not be obtained, while if it is too low, the diagnostic accuracy is impaired, and it is experimentally confirmed that 0.85 is appropriate.

Further, with respect to this specified lead, difference data at 15-second intervals are successively created for both types of data, using the ST level and the heart rate stored in the RAM when the exercise load start signal is generated as reference values. The horizontal axis is the heart rate difference, and the heart rate difference at the start of the load is 0%, and the heart rate difference at the end of the load is 100%. On the other hand, the ST level difference is the vertical axis, and the S at the start of the exercise load is S.
T level difference is 0%, ST level difference at the end of load is 1
Set to 00%. Then, the% value of the ST level difference captured at almost the same time point with respect to the% value of the heart rate change difference is created as plot data with 100% as the origin, corresponding to the decrease of the ST level due to the exercise load.

Furthermore, a standard HR recovery period, for example, 6 minutes from the end of the exercise load is timed by the timer 17, and the ST level and the heart rate are captured every 15 seconds for the specified lead.
The same plot data is created every 15 seconds. Then, for the data group of the three plot data 45 seconds after the end of the load and the data group in which the plot data is sequentially increased one by one according to the time elapse until after 6 minutes, the maximum slope is obtained by the same method as described above. Find the value. Further, during the recovery period of HR, the difference data between the ST level and HR is made to correspond to the coordinates of the plot data at the end of the exercise load, and the plot data Pr is created in the same manner.

The numerical indicators 14 and 14a numerically display the maximum inclination value during load and during recovery as a diagnostic index, and the indicator 14
b indicates the type of the induction, and the cathode ray tube 15 displays both plot data Pe and Pr.

Next, the operation of the heart diagnostic apparatus configured as described above will be described in the fourth section.
This will be described with reference to the flowchart shown in the figure.

When the treadmill starts the exercise load on the subject and the switch 16 is operated at the same time, the microcomputer 1
3 holds the ST level and HR data detected by the microcomputer 12 as reference values, and takes in these data at 15-second intervals. Then, the ST level / HR plot data is created for each lead, and the maximum load of each lead is reached when the load is operated by operating the switch 16a due to the occurrence of lower limb fatigue, occurrence of chest pain, etc. over the standard load time. The slope value is calculated, and the maximum slope value and the type of its guidance, which are diagnostic indexes, are specified. Subsequently, the maximum slope value in the recovery period of the identified lead is detected. In addition, difference data for the reference values of both types are sequentially created, and S for the HR difference value of 0% to 100% every 15 seconds is created.
Plot data of T level difference% value is created.

As a result, the numerical indicators 14, 14a, 14b are instructed about the maximum inclination value at the time of load and during the recovery period and the guidance for belonging to the numerical indicators 14, and diagnosis can be made from the magnitude. Plot data Pe is displayed on the cathode ray tube 15 as, for example, a white circle, and a reference line (a plot line in the case of completely corresponding relationship during exercise load,
That is, the size of the convex or concave portion with respect to the diagonal line connecting the extreme scale values can be monitored. During the recovery period, the mark of the plot data Pr is displayed in white on the cathode ray tube 15 (black mark in the figure).

FIG. 5 and FIG. 6 show actual test data according to the above-described examples of subjects with non-specific ST level depression and subjects with severe myocardial ischemia diagnosed by myocardial scintigraphy and the like. That is,
In the case of FIG. 5, the plot data Pe is distributed in the vicinity of the reference line B and the area of +-is mixed with respect to the reference line B, whereas in the case of FIG. 6, the intensity is convex. Thus, it can be seen that the area value of the convex portion is displayed as a + value correlated with the degree of myocardial ischemia. Further, the plot data Pr in the recovery period exhibits a transient convex pattern in the case of FIG. 5, and exhibits the inverse α pattern as a whole when the plot data Pe and Pr are combined, whereas in the case of FIG. No transient convex pattern was observed in the mouse, and a spindle-shaped pattern as a whole is also a diagnostic criterion.

FIGS. 7 and 8 show test data of the actual maximum slope values according to the above-described examples of a normal subject and a subject with severe myocardial ischemia as well. That is, in FIG. 7, the correlation coefficient 0.
From the regression line Se with a maximum slope of 85 or more, the maximum slope value is
It becomes 3.2 μV / beats / minute. On the other hand, the regression line S of the maximum slope for the abnormal plot data in FIG.
The maximum slope value of e is 9.4 μV / beat rate / minute. Similarly, the regression line Sr of each maximum slope in the recovery period
The maximum slope value of is determined as 11.1 and 3.8 μV / beat rate / minute, and provides supplementary diagnostic information. Therefore,
Along with the diagnosis of myocardial ischemia based on such curve data,
The diagnostic index of the ST level / HR slope value enables reliable and quantitative diagnosis.

In order to confirm the effect of the present invention, FIG. 9 shows about 60 cases in which the horizontal axis represents the area value in the plot data curve with respect to the reference line and the vertical axis represents the maximum slope value. A test example is shown. That is, in the case of a normal person, they are concentrated in the area A close to the origin, and in the case of myocardial ischemia, they are dispersed in the area B in which both values are large, and they are clearly discriminated without overlapping in both areas. It That is, it is found that the reliability of the diagnosis of the present invention is extremely high, and when the inclination value is large, it is immediately judged as abnormal, and even when the inclination value is close to the normal value, it is possible to make a distinction depending on how large the area value is. As described in detail in the specification of Japanese Patent Application No. 53-68256, the area value is obtained by smoothing the plotted data with respect to the reference line with a three-dimensional curve and then adding + or-sign on either side of the reference line. And calculated. Therefore, the maximum slope value may be, in addition to or instead of the above-mentioned simple numerical display,
It is also effective in terms of diagnosis to plot on the orthogonal coordinates of the area value and the inclination value and display them on the screen.

In the above-described embodiment, it is possible to eliminate the switch 16a and automatically generate the exercise load end signal based on the diagnostic data such as the sequentially calculated area value. It is also meaningful that the slope value is displayed on the screen, for example, as a bar graph for all the leads, and the area plot data can also be displayed for all the leads. The plot data may be displayed as a continuous line.

〔The invention's effect〕

As described above, according to the present invention, a diagnostic result for myocardial ischemia is automatically output immediately after a single exercise load by a method based on the HR level and the ST level. At this time, in addition to observing the plot curve of the ST level decrease rate with respect to the heart rate increase rate, the ST level / HR slope value is output as a diagnostic index, so that both information is taken into consideration and the reliability is extremely high. Diagnosis is possible. The diagnosis for the false positive group will also be accurate.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a heart diagnostic apparatus for exercise load according to the present invention, FIG. 2 is a diagram for explaining its operation, FIG. 3 is a diagram showing a configuration according to an embodiment of the present invention, and FIG. 5 is a flow chart for explaining the operation of the embodiment, FIGS. 5 to 8 are views showing data actually tested by the embodiment, and FIG. 9 is a test example for confirming the reliability of diagnosis according to the embodiment. It is the data shown.

Claims (1)

[Claims] 1. An SDS of a plurality of types of lead electrocardiographic signals detected by an electrocardiographic signal detection unit for a subject who has been exercised.
ST level detection means for detecting each T level, heart rate detection means for deriving a heartbeat signal from the detected electrocardiogram signal to detect a heart rate per unit time, and the heart rate as one coordinate axis of orthogonal coordinates. , S for the heart rate detected at a predetermined time interval from a predetermined time point at the start of load with the ST level as the other coordinate axis
First plot data creating means for creating the first plot data in which the T level is plotted for each of the leads, and a data group of a predetermined number of the first plot data traced back from the load end time to the predetermined time Slope value calculating means for calculating slope values of regression lines each having a predetermined correlation coefficient or more for a plurality of data groups in which the number of data is increased by sequentially adding the first plot data toward the predetermined time point. A slope specifying means for specifying a maximum slope value among the slope values for all types of the guide and a type of the guide to which the maximum slope value belongs, and the S detected at the predetermined time point of the specified guide.
ST level difference detecting means for detecting an ST level difference with respect to a T level at each of the predetermined time intervals, and heart rate difference detecting means for detecting a heart rate difference with respect to the heart rate detected at the predetermined time point at each of the predetermined time intervals And the heart rate difference is one coordinate axis of rectangular coordinates, the heart rate difference at the predetermined time point is 0%, the heart rate difference at the end of the load is 100% coordinate value, and the ST level difference is the other. The ST level difference at the predetermined time point is 0%, and the ST level difference at the end time of the load is 100%.
Second plot data creating means for creating at least the specified lead, second plot data plotting the% value of the ST level difference with respect to the detection time point of the% value of the heart rate difference as the coordinate value of%. An output means for displaying the second plot data on a plane of orthogonal coordinate axes and outputting a diagnostic index corresponding to the maximum inclination value.