KR101536361B1 - Method for analyzing ecg and ecg apparatus therefor - Google Patents

Abstract

The present invention relates to an electrocardiogram device, and more particularly, to a method for analyzing an electrocardiogram signal, which can accurately measure an electrocardiogram by correcting an error occurring in analyzing an electrocardiogram signal in a portable electrocardiogram device having a low sample rate, and an electrocardiograph device using the same. According to another aspect of the present invention, there is provided a method for analyzing an electrocardiogram signal, comprising: classifying a predetermined number of successive R peaks in an electrocardiogram and classifying a rising section and a falling section based on respective R peaks; Calculating a correction value of the corresponding R peak using a regression line corresponding to the rising section and the falling section; And an analysis step of analyzing the electrocardiogram signal using the correction value, and an electrocardiogram device using the method.

Electrocardiogram, sample rate, R peak, RR interval, Heart Rate Variability (HRV), Pulse Transit Time (PTT)

Description

Technical Field [0001] The present invention relates to a method of analyzing an electrocardiogram signal,

The present invention relates to an electrocardiogram device, and more particularly, to a method for analyzing an electrocardiogram signal, which can accurately measure an electrocardiogram by correcting an error occurring in analyzing an electrocardiogram signal in a portable electrocardiogram device having a low sample rate, and an electrocardiograph device using the same.

In general, heart rate variability (HRV) analysis is utilized as a quantitative and objective evaluation of autonomic nervous system. To improve the reliability of this HRV analysis, accurate electrocardiogram (ECG) signals should be analyzed. Typically, HRV (Heart Rate Variability) or PTT (Pulse Transit Time) is usually analyzed according to a high sample rate of 500-1000 Hz or more.

In particular, HRV can be determined by the RR interval that appears continuously in the electrocardiogram. At this time, a relatively accurate R waveform can be obtained when the electrocardiogram signal is sampled at least 500 Hz. On the other hand, if the electrocardiogram signal is sampled below 500 Hz, an incorrect HRV analysis is performed due to a large error in the R waveform.

However, in the case of a portable electrocardiograph, there is a limitation in HRV (Heart Rate Variability) or PTT (Pulse Transit Time) analysis because it is required to reduce the sampling rate to 500 Hz or less for low power as well as a lack of storage space due to miniaturization. That is, in the case of the portable electrocardiogram apparatus, since the electrocardiogram signal is applied at a sample rate of 500 Hz or less, the signal quality may not be lowered or the position of the R waveform signal may not be precisely recognized and the accuracy and reliability of the electrocardiographic information can not be expected .

To this end, a method using zero padding in the frequency domain has been proposed. This is a method of obtaining the position of the R peak at the improved resolution after interpolation, and there is a limit in that the processing accuracy in the time domain is lowered.

Therefore, in acquiring the RR interval in the electrocardiogram obtained according to the sample rate of 500 Hz or less in the portable electrocardiogram stop, it is necessary to propose a method of compensating the error to obtain the RR interval.

Therefore, the present invention calculates the time coordinates of the R peak (R peak) by analyzing the regression line of the samples using the QRS complex morphological characteristic of the electrocardiogram in the electrocardiogram device having a low sample rate (for example, 500 Hz or less) (Heart rate variability), PTT (pulse transit time), and the like, which are electrocardiographic information, as an evaluation index of the autonomic nervous system, by acquiring an ECG signal having an error corrected And to provide an electrocardiogram signal analyzing method using the electrocardiogram signal analyzing method.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention which are not mentioned can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. It will also be readily apparent that the objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

According to an aspect of the present invention, there is provided a method for analyzing an electrocardiogram signal, the method comprising: selecting a predetermined number of successive R peaks in an electrocardiogram, And a descending section; Calculating a correction value of the corresponding R peak using a regression line corresponding to the rising section and the falling section; And analyzing the electrocardiogram signal using the correction value.

According to another aspect of the present invention, there is provided an electrocardiogram apparatus comprising: electrocardiogram sensing means for sensing a predetermined number of consecutive R waveforms by sensing an electrocardiogram; And an electrocardiogram correction means for calculating a correction value of a corresponding R peak using a regression line corresponding to a rising section and a falling section classified based on the R peak of the R waveform and analyzing the electrocardiogram signal using the correction value .

A computer-readable recording medium having recorded thereon a program according to another aspect of the present invention is a computer-readable recording medium for storing a predetermined number of successive R peaks in an electrocardiogram (ECG) A function of classifying the rising section and the falling section; Calculating a correction value of the corresponding R peak using a regression line corresponding to the rising section and the falling section; And a function of analyzing the electrocardiogram signal using the correction value.

The present invention as described above can be applied to an electrocardiogram (ECG) apparatus having a low sample rate (for example, 500 Hz or less) by analyzing a regression line of samples using a QRS complex morphological characteristic of an electrocardiogram It is possible to acquire an electrocardiogram signal having an error corrected (i.e., an RR interval) by calculating coordinates.

Further, the present invention has an effect of extracting HRV (Heart Rate Variability) or PTT (Pulse Transit Time) by obtaining an RR interval in which an error is corrected in an electrocardiogram apparatus having a sample rate of 500 Hz or less.

Further, the present invention is applied to a portable electrocardiogram apparatus having a sample rate of 500 Hz or less, thereby enabling accurate electrocardiogram measurement together with portability, thereby increasing the reliability of a user.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings, It can be easily carried out. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of an electrocardiogram apparatus according to an embodiment of the present invention.

1, an electrocardiogram apparatus (hereinafter, referred to as "ECG apparatus") according to the present invention is a system for measuring an HRV (Heart Rate Variability) and a PTT (Pulse Transit Time) (Here, 200 Hz of 500 Hz or less) than the sample rate of Hz to 1000 Hz or more is applied, and the R peak (R peak) to improve the accuracy of the RR interval. Thus, the electrocardiogram device of the present invention can accurately extract and analyze electrocardiographic information HRV, PTT as an evaluation index of autonomic nervous system.

It will be appreciated by those skilled in the art that the electrocardiographic apparatus of the present invention can be applied to a case of a small and portable type that applies a low level of sample rate, but is not construed to be limited thereto.

Specifically, the electrocardiogram device according to the present invention includes an electrocardiogram sensing unit 110, an electrocardiogram signal correction unit 120, and an electrocardiogram information providing unit 130.

The electrocardiogram sensing unit 110 is an electrocardiogram sensor capable of sensing an electrocardiogram of a subject, such as an abdomen, a chest, a wrist and an arm of a subject. At this time, the electrocardiogram sensing unit 110 measures an electrocardiographic waveform (that is, a P wave, a Q wave, an R wave, an S wave, and a T wave) reflecting the electric activation state of the heart of the subject and provides the measured electrocardiogram to the electrocardiogram correcting unit 120 .

The electrocardiogram correction unit 120 calculates the 'RR interval' by checking the position of the R waveform from the morphological characteristics of the QRS complex of the electrocardiographic waveform of the subject provided from the electrocardiogram sensing unit 110, At this time, by applying the corrected R peak through the regression analysis of the rising section and the falling section constituting the QRS complex, in particular, the R waveform, the error of the R waveform according to the low sample rate (that is, 200 Hz below 500 Hz) After the correction, the RR interval is calculated (see FIG. 2 to be described later). Here, the morphological characteristic of the QRS complex of the electrocardiographic waveform indicates that the number of values constituting the rising section is smaller than that of the rising section (i.e., Is smaller than the number of values that constitute the.

The electrocardiogram information providing unit 130 uses the RR interval calculated by the electrocardiogram correcting unit 120 to calculate heart rate variability (HRV), pulse transit time (PTT), and the like, which are electrocardiographic information, according to a conventional method that can be easily understood by those skilled in the art Extract and provide the result. For example, the electrocardiogram information providing unit 130 represents HRV by converting the RR interval from the R peak calculated from the electrocardiogram correcting unit 120 into a time-series signal and rearranging it on the time axis.

In addition, the electrocardiogram device of the present invention may further include a user interface (e.g., an electrocardiogram waveform) of the subject sensed by the electrocardiogram sensing unit 110 or a HRV of the subject analyzed by the electrocardiogram information providing unit 130 For example, a monitor, etc. (not shown in Fig. 1).

FIG. 2 is a diagram for explaining a process of calculating time coordinates of an R peak corrected by the electrocardiogram compensating unit according to the present invention. Here, the x-coordinate in Fig. 2 indicates the time, and the y-coordinate indicates the intensity of the heartbeat signal.

The electrocardiogram compensation unit 120 selects a predetermined number (for example, 10) of arbitrary consecutive QRS intervals (i.e., R waveforms) from the electrocardiogram waveform sensed by the electrocardiogram sensing unit 110. [ At this time, the electrocardiogram compensating unit 120 calculates the RR interval by calculating the time coordinates of the R peak of each selected QRS interval and then arranging it in a time series.

For this, the electrocardiogram compensation unit 120 calculates the time coordinates of the R peak in one QRS interval as shown in FIG. 2 as follows.

First, the electrocardiogram compensating unit 120 confirms the R-peak of the QRS interval using the morphological characteristic of the QRS complex in the ECG waveform as described above. At this time, the electrocardiogram compensating unit 120 classifies a section showing a steep slope about the R peak, that is, a section showing a rising section and a gentle slope, that is, a falling section.

Thereafter, the electrocardiogram compensating unit 120 obtains the regression line equation of each interval through the regression analysis for each of the rising interval and the falling interval as Equation (1).

y = ax + b

Where a is the slope of the regression line (i.e., regression coefficient), and b is the y-axis intercept of the regression line. Accordingly, in Fig. 2, the regression line of the rising section is y ₁ = a ₁ x + b _1, and the regression line of the falling section is y ₂ = a ₂ x + b ₂ .

Next, the electrocardiogram compensating unit 120 calculates the x coordinate of the contact point where the regression line of the rising section and the falling section meet, that is, the time coordinate (i.e., x coordinate) of the R peak as shown in the following equation (2).

The rising section: y ₁ = a ₁ x + b ₁

Falling period: y ₂ = a ₂ x + b ₂

X coordinate of the contact: x = (b ₂ -b ₁ ) / (a ₁ -a ₂ )

Here, the x-coordinate of the contact point where the regression line of the rising section and the falling section meet corresponds to the time coordinate of the R peak whose error is corrected. At this time, the x-coordinate of the contact point can be changed depending on how many regression analysis coordinates are included when the regression line corresponding to the rising section and the falling section is derived. Preferably, the electrocardiogram correcting unit 120 of the present invention includes five coordinates including four peaks in the rising section and an R peak in the falling section, as shown in FIG.

As described above, the electrocardiogram compensating unit 120 can calculate the RR interval with improved accuracy at a low sample rate by calculating the time coordinates of the R peak corrected for each QRS interval.

On the other hand, the results of comparing the error range with 1000 Hz where the sample rate is 500 Hz or more when the present invention is applied and when the present invention is applied when the sample rate is 200 Hz or less will be explained. At this time, when the sample rate is 200 Hz, the electrocardiogram signal is not soft compared with the electrocardiogram signal when the sample rate is 1000 Hz, and the positions of R peak are different from each other.

In order to explain this, subjects were shown electrocardiogram states as shown in Table 1 below when sitting and cycling.

When you are sitting When cycling Average heart rate 65.8 bpm 103.2 bpm Average RR interval 912.9ms 582.2ms R peak number (experimental time: 5 minutes) 329 516

That is, the average heart rate of the subjects was 65.8 bpm when sitting, 103.2 bpm when cycling, and the average RR intervals were 912.9 ms and 582.2 ms, respectively. The experimental time was 5 minutes each, and the number of R peak was 329 when sitting and 516 when cycling.

First, the average and standard deviation of the RR interval of 200 Hz applied with the present invention and the RR interval of 200 Hz of the present invention are shown in Table 2 below. Here, for convenience of explanation, '200 Hz applied to the present invention' is referred to as 'IP200 Hz'.

When you are sitting When cycling 200Hz vs
1000 Hz IP200㎐ vs
1000 Hz 200Hz vs
1000 Hz IP200㎐ vs
1000 Hz Average 0.2 0.2 0.12 0.12 Standard Deviation 12.31 2.3 2.24 0.94

As shown in Table 2, the average of the errors does not change. However, the standard deviation of the error when sitting is 12.31 when the present invention is not applied (i.e., 200 Hz vs. 1000 Hz) and 2.3 when the present invention is applied (IP200 Hz vs. 1000 Hz) More than six times. Similarly, the standard deviation of the error when cycling is 2.24 when the present invention is not applied (i.e., 200 Hz vs. 1000 Hz) and 0.94 when the present invention is applied (IP200 Hz vs. 1000 Hz) About two times less.

Next, when the present invention is not applied (see FIGS. 3A and 4A to be described later) and when the present invention is applied (see FIGS. 3B and 4B to be described later) as a Blend-Altman plot As follows.

That is, FIG. 3A is a view showing an error of 200 Hz and 1000 Hz in which the subject of the present invention is not applied when the subject is sitting, FIG. 3B is a graph showing an error of 200 Hz and 1000 Hz FIG. 4A is a view showing an error of 200 Hz and 1000 Hz in which the present invention is not applied when the subject is cycling. FIG. 4B is a graph showing an error of 200 Hz applied with the present invention when the subject is cycling. And an error of 1000 Hz.

It can be understood that the error range is reduced in both sitting and cycling, as shown in Figs. 4A and 4B as well as Figs. 3A and 3B.

5 is a flowchart illustrating an electrocardiogram signal analysis method according to an embodiment of the present invention.

Referring to FIG. 5, the electrocardiogram apparatus of the present invention selects a predetermined number of consecutive R peaks in an electrocardiogram and classifies the rising and falling intervals of each R peak based on each R peak (S501).

Thereafter, the electrocardiogram apparatus obtains a regression line equation corresponding to the rising section and the falling mouth, and then calculates the time coordinates of the R peak whose error is corrected, that is, the x coordinate of the contact point of the regression line corresponding to the rising section and the falling mouth (S503). At this time, the time coordinate of the R peak is a value in which the error is corrected at the corresponding R peak selected from the electrocardiogram.

Then, the electrocardiogram apparatus obtains the RR interval, which is the electrocardiogram signal, using the corrected value of the R peak, that is, the time coordinate of the R peak with the error corrected (S505). At this time, the electrocardiogram apparatus may extract HRV (Heart Rate Variability) or PTT (Pulse Transit Time) which is an evaluation index of the autonomic nervous system using the RR interval (S507).

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. The present invention is not limited to the drawings.

1 is a configuration diagram of an electrocardiogram apparatus according to an embodiment of the present invention;

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an electrocardiogram (ECG) compensator.

FIG. 3A shows an error of 200 Hz and 1000 Hz in which the present invention is not applied when the subject is sitting. FIG.

FIG. 3B is a view showing an error of 200 Hz and 1000 Hz to which the present invention is applied when the subject is sitting. FIG.

4A is a graph showing an error of 200 Hz and 1000 Hz in which the present invention is not applied when a subject is cycling;

FIG. 4B is an illustration showing an error of 200 Hz and 1000 Hz to which the present invention is applied when a subject is cycling; FIG.

5 is a flowchart illustrating an electrocardiogram signal analysis method according to an embodiment of the present invention.

DESCRIPTION OF THE REFERENCE SYMBOLS

110: electrocardiogram detection unit 120: electrocardiogram correction unit

130: Electrocardiogram information providing service

Claims (17)

A method for analyzing an electrocardiogram signal, A classifying step of classifying a rising section and a falling section of each of the R peaks by selecting a predetermined number of successive R peaks (R peak) in the electrocardiogram; Calculating a correction value of the corresponding R peak using a regression line corresponding to the rising section and the falling section; And And analyzing the electrocardiogram signal using the correction value, Wherein the calculating step calculates a time coordinate of a contact point between a regression line corresponding to the rising section and the falling section as a correction value of the R peak. The method according to claim 1, Wherein the classifying step comprises: Wherein each R peak is selected using the morphological characteristics of a QRS complex in an electrocardiographic waveform. 3. The method of claim 2, Wherein the classifying step comprises: Wherein the rising section and the falling section are classified according to a slope of each section around each R peak. delete The method according to claim 1, Wherein the position of the time coordinate is And the number of regression analysis coordinates to be included in the regression line corresponding to the rising section and the falling section. The method according to any one of claims 1 to 3 and 5, The electrocardiogram signal includes: Wherein the RR interval is an RR interval. The method according to claim 6, Extracting and providing HRV (Heart Rate Variability) or PTT (Pulse Transit Time) which is an evaluation index of the autonomic nervous system using the RR interval Further comprising the steps of: 8. The method of claim 7, Wherein the classifying step comprises: Wherein a predetermined number of R peaks are selected according to a sample rate of 500 Hz or less for a portable electrocardiogram apparatus. In an electrocardiogram apparatus, Electrocardiogram sensing means for sensing a predetermined number of consecutive R waveforms by sensing an electrocardiogram; And An electrocardiogram correction means for calculating a correction value of the corresponding R peak using a regression line corresponding to a rising section and a falling section classified based on the R peak of the R waveform and analyzing the electrocardiogram signal using the correction value and, Wherein the correction value is a time coordinate of a contact point between a regression line corresponding to the rising section and the falling section. 10. The method of claim 9, The R-peak of the R- Wherein the electrocardiogram is selected using the morphological characteristics of a QRS complex in the electrocardiogram. 10. The method of claim 9, The rising section and the falling section may include: And wherein the ECG signal is classified according to a slope of each section around an R peak of the R waveform. delete 10. The method of claim 9, Wherein the position of the time coordinate is And the number of regression analysis coordinates to be included in the regression line corresponding to the rising section and the falling section. 14. The method according to any one of claims 9 to 11 and 13, The electrocardiogram signal includes: And an RR interval (RR interval). 15. The method of claim 14, An electrocardiogram information providing means for extracting and providing an HRV (Heart Rate Variability) or a PTT (Pulse Transit Time), which is an evaluation index of an autonomic nervous system, Further comprising an electrocardiogram device. 16. The method of claim 15, Wherein the electrocardiogram sensing means comprises: And a predetermined number of R peaks are selected according to a sample rate of 500 Hz or less for the portable electrocardiogram apparatus. An electrocardiogram apparatus having a processor, Selecting a predetermined number of successive R peaks from the electrocardiogram and classifying the rising and falling intervals of each R peak around the peak; Calculating a correction value of a corresponding R peak, which is a time coordinate of a contact point between the rising section and the return section corresponding to the falling section; And A function of analyzing the electrocardiogram signal using the correction value Readable recording medium having recorded thereon a program for realizing the program.

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