KR19980030894A - How to Display Characteristics for Estee Segments and Tifa of ECG Signals - Google Patents

Abstract

The present invention relates to a method for displaying characteristics of the ST segment and the T wave of an ECG signal. The present invention relates to the ST segment and the T wave on the basis of the start point and the end point of the dominant QRS complex determined based on the frequency from the ECG signal from which the baseline fluctuations are removed. After the amplitude set is determined, the ST segment and the T wave having a relatively small RR interval are excluded from the characteristic display process due to the distribution characteristics of the amplitude set, and the ST segment and the T wave having a maximum deviation greater than a predetermined threshold are represented. According to the method for displaying characteristics of the ST segment and the T wave of the ECG signal according to the present invention, which can extract accurate diagnostic parameters by excluding the PQRST complex extraction process, the ST segment and the T wave are applied to the ECG signal having a low signal to noise ratio. Negative Zeros of Noise Components Occurred When Extracting Diagnostic Parameters The fragrance can be effectively removed and high reliability of ST segment and T wave component diagnosis can be achieved by appropriately responding to the distortion of ST segment and T wave caused by the incompleteness of the baseline fluctuation removal technique and local derailment at the baseline. It can be secured.

Description

Characterization method for S-Te segment and T-wave of ECG signal.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrocardiogram automatic diagnosis method for diagnosing a disease by detecting an electrical signal from the heart in the field of biosignal processing. The electrocardiogram signal includes an ST segment and a ST segment. A method of typification of the ST segment and the T wave of an ECG signal expressing the characteristics of the ST segment and the T wave by using the distribution property of the amplitude set for the T wave (hereinafter, referred to as a T wave business card). will be.

Here, the characteristic display for the ST segment and the T wave refers to performing a kind of pattern matching for the ST segment and the T wave, and distinguishing whether the ST segment and the T wave form are identical or different among the ECG signals. It refers to a series of processes, such as removing the ST segment and the T wave, which have a shift in the process of selecting a representative PQRST complex for extracting the diagnostic parameters for the ECG signal.

The present invention is a part of the automatic diagnostic algorithm that is the core of the ECG device, and the new ST segment and the T-wave which can satisfy the requirements for mounting on the ECG device, that is, accuracy and real-time detection possibility simultaneously. It relates to a method of displaying the characteristics.

Figure 1 shows the electrical conduction system and the electrocardiogram generation process of the heart, as can be seen in Figure 1 (A), the heart is largely left atrioventricular (LA; Right Atrioventricular) and left and right ventricle (LA) LV (Left Ventricular, Right Ventricular), the electrical system of the heart is the sinotrial node (SA node), which causes the impulse to start contraction of the heart and acts as a pacemaker, and the sinus node (SA node) Atrioventricular node (AV node), Heatle bundle of His and left and right bundle branch and Perkins fiber network, which provide paths to deliver electrical impulses from the left and right ventricle (LV, RV) It consists of a (Firkinse fiber network).

When the SA node generates electric impulse and depolarizes the atrium, the impulse is left and right bundle branch through the atrium node (AV node) and the hiss bundle (Hundle of His). ) And then through the Perkins fiber network to the ventricular to depolarize the ventricles.

Electrical impulses from the eastern nodules (SA nodes) flow through the two atria and constrict the atria, whereby the current generated by the contraction of the atria is measured as a potential difference through the electrodes of the leads attached to the surface. When recorded, a waveform having a small curve as shown by the solid line in FIG. 1B appears. This waveform is called P wave.

When the impulse arrives at the atrial node (AV node), a slight delay occurs. As shown in (C) of FIG. 1, a time interval including the P wave and the delay time is called a PR interval, and after the PR interval. The impulse descends rapidly through the heath bundle between the atrium muscle diaphragms, activating the muscle septum from side to side.

The above-mentioned activity of the muscular diaphragm causes twisting of the first ventricle, resulting in a waveform as shown in (D) of FIG. 1, which is called a Q wave.

Then, the impulse rapidly spreads through the conducting tissue of the ventricles, causing the largest ventricular distortion, wherein the generated waveform is R pie, and the S wave is generated after the conducting process for all parts of the ventricles.

As shown by a solid line in FIG. 1E, waveforms of three waves, that is, Q waves, R waves, and S waves, are generated. A group of these waveforms is referred to as a QRS complex. Contract and pump blood.

Thereafter, there is a relatively short period of inactivity, which is recorded as the ST segment of FIG. 1f, and during the recovery period, the heart undergoes repolarization and the waveform generated is shown in FIG. T wave.

A series of waveform groups consisting of the above-described P wave, QRS complex, ST segment, and T wave is defined as PQRST complex. At this time, the PQRST complex has a periodicity and becomes a basic unit for analyzing and diagnosing an electrocardiogram signal.

As the ECG is repeatedly performed in a series of combined operations, abnormal ECG waveforms are generated when a disease occurs in a series of electrical conducting systems. That is, atrial palpation and fibrillation occur when the nodule (SA node) is inoperable, and when the ventricular itself is abnormal, it may appear as a disease such as ventricular extravasation or ventricular fibrillation.

As shown in FIG. 2, the diagnostic parameters used in the ECG diagnostic apparatus include the interval PRd between the start point of the P-wave and the start point of the QRS complex, the distance between the start point and the end point of the QRS complex, and the QRS complex. Time such as the interval between the starting point and the end of the T wave (QTd), the Q wave spacing (Qd), the R wave spacing (Rd), the S wave spacing (Sd), the RR spacing between any R wave and the next R wave immediately adjacent to it. and parameters related to amplitude, such as Q wave amplitude Qa, R wave amplitude Ra, S wave amplitude Sa, and T wave amplitudes T1a and T2a. .

In addition to the above parameters, QRS complex form, P wave form and the like are also used, but most of them use the parameters related to time and amplitude to diagnose the abnormal state of the heart and the type of disease.

The conventional method of extracting diagnostic parameters for an ECG signal obtains individual diagnostic parameters (ie, P wave amplitude, PR interval, Q wave amplitude, S wave amplitude, QRS interval, T wave amplitude, etc.) for each PQRST complex. Finally, it is common to calculate the average of these parameters and use them as diagnostic parameters for diagnosing ECG.

The present invention relates to a method for displaying characteristics of an ST segment and a T wave of an ECG signal. Referring to a method of displaying characteristics of an ST segment and a T wave according to the prior art, the present invention relates to a method of extracting a diagnostic parameter for an ECG signal. Similarly, after obtaining the individual diagnostic parameters through the characteristic display of the ST segment and the T wave, finally extracting the diagnostic parameters for the ST segment and the T wave by calculating the average value of the individual diagnostic parameters for the ST segment and the T wave. It is common.

However, the conventional diagnostic parameter extraction method for the ST segment and the T wave has an ECG signal having a low signal-to-noise ratio (SNR) (i.e., when a noise component is introduced into the ECG signal). When the diagnostic parameters for the ST segment and the T wave are extracted, the distortion is generated by the noise component, and by taking a simple average of the individual diagnostic parameters for the distorted ST segment and the T wave, The effect is reflected on the extracted average diagnostic parameters as an average value without filtration. In particular, the high frequency noise component causes more severe distortion in the average diagnostic parameters for the extracted ST segment and T-wave, further increasing the reliability of the diagnostic results. There is a problem of further deterioration.

Accordingly, the present invention has been made to solve such a problem, to obtain a representative PQRST complex through the averaging process for each PQRST complex having the same shape, and to use the representative PQRST complex to determine the diagnostic parameters In the extraction method, the characteristics of the ST segment and the T wave are displayed by using the distribution property of the amplitude set of the ST segment and the T wave, thereby increasing the signal-to-noise ratio of the ST segment and the T wave, and thus, negative effects of the noise component (especially, The purpose of the present invention is to provide a characteristic display method for ST segments and T waves of an ECG signal that can extract accurate diagnostic parameters for ST segments and T waves.

On the other hand, among the many diagnostic parameters related to electrocardiogram, the QRS complex has the same shape, but distortions occur frequently in the ST segment and the T wave, which is incomplete in the baseline drift elimination technique. It is caused by local derailment at the baseline.

Due to this reason, when the diagnostic parameters for the ST segment and the T wave are obtained using the PQRST complex in which the distortion of the ST segment and the T wave occurs, the diagnostic result for the ST segment and the T wave component is distorted. Is likely to be

Therefore, the present invention detects the ST segment and the T wave that may cause distortion based on the distribution characteristics of the amplitude sets for the ST segment and the T wave, and then averages the ST segments and the T wave for the characteristic display. The purpose of the present invention is to provide a method for displaying characteristics of ST segments and T waves of an ECG signal which can be extracted from accurate diagnostic parameters.

1 is an exemplary view showing the electrical conduction system and electrocardiogram generation process of the heart,

Figure 2 is an exemplary view showing a representative diagnostic parameter used in automatic electrocardiogram, Figure 3 is a flow chart showing the procedure of the characteristic display method for the S-T segment and T-wave of the ECG signal according to the present invention, Figure 4 Exemplary waveform diagram of the electrocardiogram signal in which the baseline fluctuation has occurred and waveform of the electrocardiogram signal in which the sudden baseline fluctuation is removed. FIG. 5 is a diagram showing an amplitude set of the ST segment and the T wave determined by performing the amplitude set determination step of the present invention. 6 is an exemplary diagram illustrating a distribution characteristic of the amplitude set of FIG. 5 using a maximum deviation, and FIG. 7 is an exemplary diagram illustrating a maximum deviation obtained through a learning set as a function of ST segments and T waves. FIG. 8 is an exemplary view showing a signal determined to have a shift in an ST segment and a T wave in a signal from which the baseline fluctuation has been removed; FIG. 9 has an outer contraction ST segment of the ECG waveform in the example shown the T-wave characteristics display process FIG.

<Description of Codes for Major Parts of Drawings>

100: amplitude set determination step 110: signal input step

120: baseline shake removal step 130: dominant QRS complex determination step

131: QRS complex determination step 132: Dominant QRS complex detection step

140: amplitude set selection step 141: end point positioning step

142: final amplitude set selection step 200: characteristic display step

210: Remove the outside contraction data step 211: RR interval measurement step

212: determination of elimination of outside contraction data 213: extraction of the first elimination amplitude set

220: shift deviation step 221: maximum shift calculation step

222: Determination of shift data removal step 230: Step of performing characteristic display

In order to achieve the above object, the ST segment and T wave characteristic display method of the ECG signal according to the present invention is based on the start point and the end point of the dominant QRS complex determined based on the frequency from the ECG signal from which the baseline fluctuations are removed. And after determining the amplitude set for the T wave, the ST segment and the T wave having relatively small RR intervals are excluded from the characteristic display process, and the maximum outlier larger than a predetermined threshold. It is possible to extract accurate diagnostic parameters by excluding ST segments and T waves having a PQRST complex extraction process.

Referring to Figure 3 attached to the characteristic display method for the ST segment and the T wave of the ECG signal according to the present invention.

According to the present invention, the ST segment and the T-wave characteristic display method of the ECG signal according to the present invention determine the QRS complex from the ECG signal from which the baseline fluctuations are removed, and the superior QRS determined based on the frequency of occurrence of the QRS complex. An amplitude set determining step (100) for determining an amplitude set for the ST segment and the T wave of the PQRST complex including the complex, and an ST segment and a T wave having a high probability of distorting the diagnostic parameter using the distribution characteristics of the amplitude set. The characteristic display step 200 is performed to exclude the data from the amplitude set and perform an averaging process for the characteristic display.

Here, the amplitude set determining step 100 detects and removes baseline shaking by applying a signal input step 110 for receiving an extension signal from each lead and a baseline shaking removal technique for the ECG signal. After calculating the spatial velocity as a multi-dimensional vector sum of slopes between adjacent samples with respect to the baseline fluctuation removing step 120 and the ECG signal from which the baseline fluctuation was removed, and determining the QRS complex from the ECG signal using the spatial velocity, A predominant QRS complex determination step 130 for determining a predominant QRS complex based on the frequency of occurrence of the QRS complex, and an ST segment and a T wave for selecting an amplitude set for ST segments and T waves based on the predominant QRS complex. The amplitude set selection step 140 of.

In the determining of the predominant QRS complex 130, the spatial velocity is calculated using a multi-dimensional vector sum using a slope between adjacent samples obtained from a lead of a lead group composed of a plurality of leads of the ECG signal from which baseline fluctuations are removed. After that, the QRS complex determination step 131 of determining the QRS complex from the ECG signal using the maximum extreme values of the space velocity and the predominance of the group of the dominant QRS complex based on the frequency of occurrence of the QRS complex And a predominant QRS complex detection step 132 for detecting a QRS complex, wherein the amplitude set selection step 140 determines the reference point using a difference and ratio between the maximum extreme value and the second largest extreme value of the predominant QRS complex. And the position of the start point and the end point of the dominant QRS complex is symmetric about the reference point. As a result, an end point positioning step 141 for determining an end point position of the QRS complex, and a final amplitude set selection for finally selecting an amplitude set by sampling the ST segment and the T wave existing within a predetermined interval from the end point position It consists of step 142.

On the other hand, the characteristic display step 200 uses the RR interval between the dominant QRS complex and the subsequent QRS complex to remove the data of the ST segment and the T-wave distorted by the outside contraction from the amplitude set to remove the first amplitude. A maximum deviation value of the first set of amplitudes is calculated by applying an outside contraction data removing step 210 constituting a set and a maximum shift formula to the first set of amplitudes of removal, and calculating a predetermined deviation value according to the maximum deviation. The data elimination step 220 constitutes a second elimination amplitude set by removing the data of the ST segment and the T wave having the maximum deviation from the first elimination amplitude set, and separately using the second elimination amplitude set. The characteristics of the ST segment and the T wave can be displayed by averaging the diagnostic parameters for the ST segment and the T wave. Properties is composed of display performed step 230.

Here, the outside contraction data removing step 210 is an RR interval measuring step 211 for measuring the RR interval between the dominant QRS complex and the subsequent QRS complex and a first set based on the RR interval of a normal ECG signal. An outside contraction data removal determining step 212 for comparing the threshold value with the RR interval and determining whether an outward contraction occurs due to whether the RR interval is smaller than the first threshold value; and determining the removal of the outside contraction data As a result of the determination in step 212, when it is determined that the outside contraction occurs as the RR interval is smaller than the first threshold value, the amplitude of the ST segment and the T wave included in the RR interval smaller than the first threshold value is measured. A first elimination amplitude set extraction step 213 constituting a first elimination amplitude set by eliminating from the set, wherein the shift data elimination step 220 A maximum deviation calculation step 221 of calculating a maximum deviation value of the first removal amplitude set by applying a maximum deviation calculation formula to the first removal amplitude set; and a training set in which a deviation occurs in the ST segment and the T wave. If it is determined that the deviation occurs in the data removal determination step 222 and the deviation data removal determination step 222 that determine whether the maximum deviation is greater than the second threshold calculated for And a second elimination amplitude set extraction step 220 for constructing a second elimination amplitude set by removing data of the shifted ST segment and the T wave from the first elimination amplitude set.

Hereinafter, the procedure of the characteristic display method for the ST segment and the T wave of the ECG signal according to the present invention configured as described above will be described in detail with reference to FIG. 3.

First, in the amplitude set determination step 100, the amplitude of the ST segment and the T wave of the PQRST complex including the predominant QRS complex determined by determining the QRS complex from the ECG signal from which the baseline fluctuations are removed and the frequency of occurrence of the QRS complex When the set is determined, the characteristic display step 200 excludes data of the ST segment and the T-wave having a high probability of distorting a diagnostic parameter by using the distribution characteristic of the amplitude set from the amplitude set and averages the characteristic for display. Do this.

At this time, when a signal is input from each lead in the signal input step 110, in the baseline shake removal step 120 is applied to detect the occurrence of baseline shake by applying a baseline shake removal technique to the ECG signal is input Remove baseline disturbances from the ECG signal.

As described above, among the plurality of diagnostic parameters related to the electrocardiogram, the QRS complex has the same shape, but distortion of the ST segment and the T wave occurs frequently.

As mentioned above, we pointed out the incompleteness of the baseline shake removal technique and the local deviation of the baseline as the cause of the distortion, but appropriately cope with various factors that provide incompleteness in the local deviation of the baseline and other baseline shake. In order to do this, you have to set up several difficulties.

In other words, in the baseline shake removal technique, since the frequency component causing the baseline shake has a low frequency characteristic similar to that of the ST segment and the T wave, the baseline fluctuation removal method does not cause distortion of the ST segment and the T wave component, There is a difficulty in having a function to selectively remove baseline fluctuation factors.

FIG. 4A is a waveform diagram illustrating an electrocardiogram signal in which sudden sudden baseline shaking occurs, and it can be confirmed that sudden sudden baseline shaking occurs between 4 to 6 seconds on a time axis.

FIG. 4B is a waveform diagram showing the ECG signal after the baseline shake is removed by the baseline shake removal technique of FIG. 4A. FIG. 4B is a sudden baseline shake occurring between 4 and 6 seconds on the time axis. Although most of them have been removed, it can be seen that they do not completely eliminate baseline agitation.

Subsequently, in the QRS complex determination step 131, the spatial velocity is calculated using a multi-dimensional vector sum using a slope between adjacent samples obtained from leads of a lead group composed of a plurality of leads, based on the ECG signal from which baseline fluctuations are removed. The QRS complex is determined from an ECG signal using the maximum extremes of the space velocity.

Here, the QRS complex determination step 131 is a space speed setting step of calculating the space velocity for the ECG signal by using the spatial characteristics of the lead group consisting of a plurality of leads, and by checking the change in the amplitude of the space velocity An effective extreme value detecting step of detecting an effective extreme value expected in the QRS complex, and a QRS complex detecting step of comparing the effective extreme values detected in the effective extreme value detecting step with a threshold value and detecting the same as a QRS complex.

The space velocity setting step includes a downsampling step of reducing the number of processed sample data by performing down sampling on the original signal, and using a three-dimensional vector sum using a respective slope of three reads having the same origin. It is composed of a space velocity calculation step of calculating the effective extrema value detection step, the local extremum value to determine the spatial velocity as a local extremum when the current amplitude value of the space velocity is greater than the previous amplitude value and the subsequent amplitude value The detection step and the maximum extreme value detection step of detecting the largest local extreme value as the effective extreme value among the local extreme values from which the spike component existing within the predetermined section is removed.

The QRS complex detection step is proportional to the maximum effective extreme value determining step of determining the maximum effective extreme value among the valid extreme values that are not labeled with the QRS complex, and the average of the maximum effective extreme values determined up to the present point in the maximum effective extreme value determination step. A QRS complex labeling step of setting a threshold value and labeling an extreme value greater than the threshold value with a QRS complex, and a threshold value set to be proportional to adjacent effective extreme values existing within a predetermined interval from the labeled QRS complex and the currently labeled effective extreme value. It is composed of a neighboring extrema removal step of determining whether to remove the relative effective extrema by comparing with.

Detailed description of the QRS complex determination step 131 of the present invention configured as described above is described in detail in the Korean patent application No. 96-18450, QRS complex detection apparatus and method using multiple reads, which is filed by the applicant. See this.

Subsequently, when the dominant QRS complex is detected in the dominant QRS complex detection step 132, the dominant QRS complex that is a group of the dominant QRS complex based on the frequency of occurrence of the QRS complex is detected. The reference point is determined by using a difference and a ratio between the maximum extreme value and the second largest extreme value of and the position of the end point of the QRS complex is determined by making the positions of the start point and the end point of the dominant QRS complex symmetric about the reference point.

Here, the end point positioning step 141 is a band pass filtering step of performing filtering using a band pass filter on the predominant QRS complexes respectively input from a plurality of leads, and the predominance filtered by the band pass filter. Among the QRS complexes, if a lead exists that satisfies the condition that the absolute value of the extreme value includes the largest extreme value (maximum extreme value) and at the same time does not include a second extreme value of the same sign that is greater than a predetermined ratio to the maximum extreme value, If a lead is selected and there are no extremes meeting the above conditions, then the ratio of the maximum extreme to the second largest extreme among the prevailing QRS complexes in each single lead (ie, A lead selection step of selecting a lead that satisfies the condition of maximum), a reference point determining step of determining the maximum extreme point of the lead as a reference point, and positions of the start point and the end point of the dominant QRS complex so as to be symmetrical about the reference point Determining the steps.

Detailed description of the end point positioning step 141 of the present invention configured as described above is described in detail in the Korean Patent Application No. 96-26678, the QRS complex characteristic display apparatus and method of an electrocardiogram signal See this.

After performing the end point positioning step 141, the final amplitude set selection step 142 selects the amplitude set by sampling the ST segment and the T wave existing within a predetermined interval from the end point position of the dominant QRS complex. Finally select.

In this case, the predetermined interval refers to the position of the end point of the T wave from the end point position of the dominant QRS complex, and the amplitude set is finally sampled at regular intervals of 20 ms intervals from the end point of the dominant QRS complex to the T wave end point. In determining the set of amplitudes, the end point position of the T wave is determined in time from the end point of the dominant QRS complex.

It is determined as a position spaced by the equation (1).

Where QT is the separation time between the end point of the dominant QRS complex and the end point of the T wave, in units of ms (milli-second), Among the RR intervals, the mean value is the median value, that is, the RR interval having a median value. The constant 250 and 5 used as the denominator are experimentally obtained values, which are related to the period of the PQRST complex. It is obvious that it can be changed to other values to obtain good performance.

5 is an exemplary diagram illustrating an amplitude set of an ST segment and a T wave determined by performing the amplitude set determination step 100.

In FIG. 5, the dotted line indicates the starting and ending points of the approximately determined QRS complex, and the dashed line represents the set of amplitudes of the determined ST segment and the T wave, and the deviation of the fifth ST segment and the T wave. It can be seen that the waveform is large.

In the characteristic display step 200, the ST segment and T-wave data of the PQRST complex having the external contraction occurred using the RR interval between the predominant QRS complex and the subsequent QRS complex in the external contraction data removal step 210 is described. Comprising a first removal amplitude set by removing from the amplitude set, in the shift data removal step 220 to calculate the maximum deviation value of the first removal amplitude set by applying a maximum shift calculation formula to the first removal amplitude set, When the second removal amplitude set is configured by removing data of the ST segment and the T-wave having a maximum deviation greater than or equal to a predetermined reference according to the maximum deviation, from the first removal amplitude set, performing the characteristic display in step 230. 2 Averaging the diagnostic parameters for ST segments and T waves separately It performs a characteristic indication of the ST segment and T wave.

Briefly, the medical term used in the above-described systolic contraction is a type of heart disease, which refers to abnormalities in the ventricles from the medical point of view, and in the ECG waveform, the QRS complex has a different form and a normal QRS complex. QRS complex appears earlier.

Thus, in the case of atrial or ventricular extraconstriction, the T wave of the predominant QRS complex located immediately before the extracontraction may overlap a portion of the front portion of the QRS complex where the extracontraction occurred.

Since the ST segment and the T wave for the predominant QRS complex should not be distorted in the averaging process to obtain a representative complex, the present invention is devised in this regard. When the RR interval between the QRS complex and the next consecutive QRS complex is measured to have a relatively short RR interval, it is assumed that an outside contraction has occurred and the data is removed from the amplitude set by removing the ST segment and the T wave within the RR interval. Construct a set of cancellation amplitudes.

That is, when the RR interval between the dominant QRS complex and the subsequent QRS complex is measured in the RR interval measurement step 211, in the determination of elimination of the contraction data 212, the experimentally set on the basis of the RR interval of the normal ECG signal By comparing the first threshold value and the RR interval, it is determined whether or not occurrence of the outside contraction occurs according to whether the RR interval is smaller than the first threshold value, and the determination result of the determination of removing the outside contraction data 212, When it is determined that the outside contraction occurs as the RR interval is smaller than the first threshold value, the first elimination amplitude set extraction step 213 extracts the ST segment and the T wave included in the RR interval smaller than the first threshold value. Construct a first set of removal amplitudes by removing from the set of amplitudes.

In this case, the first threshold value, which is a criterion for determining a relatively short RR interval, is a mid-value of the RR interval used in Equation 1. Select the smaller of two values from 100ms subtracted from and 600ms experimentally determined.

It is well known that the amplitude set determination step 100 and the outside contraction data removal step 210 described above should be applied to all leads, respectively, and the outside contraction data removal step 210 is the endpoint positioning step 141. It is obvious that such a change of order is included in the spirit of the present invention as it does not provide an error in the overall execution process even if inserted before or after the operation).

Subsequently, in the deviation data removing step 220, the maximum deviation value of the first removal amplitude set is calculated by applying the maximum deviation calculation formula to the first removal amplitude set in the maximum deviation calculation step 221, and then the shift data In the elimination determination step 222, it is determined whether the maximum deviation is greater than the second threshold calculated for the training set, and as a result of the determination of the deviation data removal determination step 222, a deviation has occurred. If it is determined that the second elimination amplitude set extraction step 220 removes the data of the ST segment and the T wave shifted from the first elimination amplitude set, a second elimination amplitude set is constructed.

At this time, the maximum deviation calculation step 221 uses the distribution characteristics of the amplitude set of the ST segment and the T wave to detect the occurrence of the deviation for the ST segment and the T wave, wherein, 1 removal amplitude set

It is represented by a determinant such as Equation 2.

Here, k represents a sequential order of the ST segment and the T wave corresponding to the first set of amplitudes to be determined, n is a circle constituting the first set of removal amplitudes determined in the characteristic display process of the ST segment and the T wave In the present invention, the number of elements constituting the amplitude set is set to 10.

In addition, the maximum deviation for each ST segment and the set of T-wave amplitudes for the determinant

It is calculated by applying Equation 3.

here, Is the column vector of the determinant shown in equation (2), The above column vector Is the average for Silver column vector Mean for columns and column vectors Is the absolute value of the difference. In the denominator of Equation 3 Column vector Standard deviation for.

The usefulness of detecting the deviation using amplitude distribution characteristics such as the maximum deviation can be easily confirmed through FIG. 6.

FIG. 6 shows the distribution characteristic of the amplitude set of FIG. 5 using the maximum deviation, and the horizontal axis shows the number of elements n of the amplitude set for the ST segment and the T wave.

Here, o denotes an ST segment and a T wave without a shift, and “x” denotes a segment where a shift occurs.

The numbers in the figures show the sequential order k of the corresponding ST segment and the T wave.

In order to determine the second threshold value, which is a threshold for detecting the presence or absence of the shift, in the present invention, 23 data in which the shift is generated in the ST segment and the T wave in the CSE database (Common Standards for Quantitative Electrocardiography data base) Is used as a training set for determining a second threshold value. FIG. 7 shows the maximum deviation obtained through the training set as a function of the ST segment and the T wave number.

Finally, the characteristic display of the ST segment and the T wave is performed by averaging the diagnostic parameters for the ST segment and the T wave separately obtained using the second elimination amplitude set in the characteristic display performing step 230.

FIG. 8 illustrates a signal determined to have a shift in the ST segment and the T wave in the signal from which the baseline fluctuation has been removed. The ST segment and the T wave, which are marked with **, that is, the ST segment and the T wave in which the shift has occurred, are representative bits. Exclude from the process of finding (representative beat).

The single PQRST complex shown on the right side of FIG. 8 shows representative bits obtained through the averaging process.

FIG. 9 shows the ST segment and T-wave characterization process in an ECG waveform having an outside contraction. The third, sixth, and ninth PQRST complexes are representative PQRSTs due to the relatively short RR intervals among Type 1, which is a dominant QRS complex. The complex is excluded from the calculation process.

As described in detail above, in the method of extracting diagnostic parameters using a representative PQRST complex, the ST segment and the T segment based on the start and end points of the dominant QRS complex determined based on the frequency from the ECG signal from which the baseline fluctuations are removed After determining the amplitude set for the wave, the ST segment and the T wave having a relatively small RR interval are excluded from the characteristic display process due to the distribution characteristics of the amplitude set, and the ST segment and T having the maximum deviation is greater than a predetermined threshold. According to the method for displaying the ST segment and the T wave of the ECG signal according to the present invention, which can accurately extract the diagnostic parameters by excluding the wave from the representative PQRST complex extraction process, the ST segment and Occurs when extracting diagnostic parameters for T-wave It can effectively remove the negative effects of Dun noise components, and respond to the ST segment and T wave distortion by appropriately responding to the distortion of ST segment and T wave caused by the incompleteness of the baseline fluctuation removal technique and the local deviation of the baseline. High reliability can be secured.

Claims (14)

In the method for extracting a diagnostic parameter for the ECG signal using a representative PQRST complex, An amplitude set determining step of determining a QRS complex from an electrocardiogram signal from which baseline shaking has been removed and determining an amplitude set for an ST segment and a T wave of a PQRST complex including a predominant QRS complex determined based on a frequency of occurrence of the QRS complex; And a characteristic display step of excluding data of the ST segment and the T-wave having a high probability of distorting a diagnostic parameter by using the distribution characteristic of the amplitude set from the amplitude set and performing an averaging process for displaying the characteristic. Characteristic method for ST segment and T wave of ECG signal. The method of claim 1, The amplitude set determining step includes a signal input step of receiving an extension signal from each lead; A baseline shake removal step of detecting and eliminating baseline shake by applying a baseline shake removal technique to the ECG signal; A space velocity between adjacent samples is calculated for the electrocardiogram signal from which baseline fluctuation has been removed, and the QRS complex is determined using the space velocity, and the predominant QRS complex determines the predominant QRS complex based on the frequency of occurrence of the QRS complex. Complex determination step; Characteristic display of the ST segment and the T wave of the ECG signal comprising the step of selecting the amplitude set of the ST segment and the T wave for selecting the amplitude set for the ST segment and the T wave on the basis of the predominant QRS complex. Way. The method of claim 1, The displaying of the characteristic may include an outer constituting a first set of removal amplitudes by removing data of the ST segment and the T wave distorted by the outside contraction from the amplitude set using the RR interval between the dominant QRS complex and the next QRS complex that is continuous. Shrink data removal; The maximum deviation value of the first removal amplitude set is calculated by applying a maximum deviation calculation formula to the first removal amplitude set, and data of the ST segment and the T wave having the maximum deviation value of a predetermined reference or more according to the maximum deviation value are calculated. Removing data from the first set of elimination amplitudes to form a second set of elimination amplitudes; An electrocardiogram comprising performing characteristic display on the ST segment and the T wave by averaging the diagnostic parameters for the ST segment and the T wave separately obtained using the second removal amplitude set. How to display characteristics for the ST segment and T wave of a signal. The method of claim 2, The dominant QRS complex determination step is to calculate the spatial velocity as a multi-dimensional vector sum using the slope between the adjacent samples obtained from the leads of the lead group consisting of a plurality of leads for the ECG signal from which the baseline fluctuations are removed, and then Determining a QRS complex from the ECG signal using extreme values of space velocity; Characteristic display of the ST segment and the T wave of the ECG signal, comprising: a predominant QRS complex detecting step of detecting the predominant QRS complex which is a dominant group of QRS complexes based on the frequency of occurrence of the QRS complex Way. The method of claim 2, The step of selecting the amplitude set determines the reference point using the difference and ratio between the maximum extreme value of the dominant QRS complex and the second largest extreme value, so that the positions of the start and end points of the dominant QRS complex are symmetric about the reference point. An endpoint location step of determining an endpoint location of the QRS complex; An electrocardiogram signal comprising a final amplitude set selection step of finally selecting the amplitude set by sampling ST segments and T waves present in a predetermined section based on the end point position of the QRS complex at predetermined intervals How to display properties for ST segment and T wave in. 6. The method of claim 5, wherein the predetermined interval is a predetermined interval of the predetermined position at the endpoint of the predominant QRS complex. Method for displaying the characteristics of the ST segment and the T wave of the ECG signal, characterized in that the time interval from the time spaced position to the end point of the T wave. 6. The method of claim 5, wherein the predetermined interval is 20 ms (milli-seconds). 7. The ECG signal position of claim 6, wherein an end point position of the T wave is a position spaced apart from an end point of the dominant QRS complex by an ms time obtained by adding 250 to a median value of the RR interval divided by 5. How to display properties for ST segments and T waves. 2. The method of claim 1, wherein the number of elements in the amplitude set is 10. The method of claim 3, wherein The step of removing the outside contraction data may include measuring an RR interval by measuring a time interval between an R wave of the dominant QRS complex and an R wave of a subsequent QRS complex; Removal of extracorporeal contraction data, which determines whether an external contraction occurs or not according to whether the RR interval is smaller than the first threshold value by comparing the RR interval with a first threshold set based on the RR interval of a normal ECG signal. Determining step; As a result of the determination of removing the contraction data, the ST segment and the T wave included in the RR interval smaller than the first threshold value are determined when it is determined that the contraction occurs because the RR interval is smaller than the first threshold value. And a first removal amplitude set extracting step of forming a first removal amplitude set by removing data from the amplitude set. 11. The characteristic indication of the ST segment and the T wave of the ECG signal according to claim 10, wherein the first threshold value is a smaller value between 100 ms subtracted from the mid-in value of the RR interval and 600 ms, which is an experimentally determined value. Way. The method of claim 3, wherein The shifting data removing step may include: a maximum shifting calculating step of calculating the maximum deviation value of the first set of removing amplitudes by applying the maximum shifting formula to the first set of removing amplitudes; Determining whether or not the maximum deviation is greater than a second threshold calculated for a training set in which an ST segment and a T wave have a deviation; If it is determined that the shift occurs in the shift data elimination determination step, the second elimination amplitude set extraction constituting the second elimination amplitude set by removing data of the shifted ST segment and the T wave from the first elimination amplitude set is extracted. Characterized by the ST segment and the T wave of the ECG signal, characterized in that consisting of a step. The ECG signal characteristic of the ST segment and the T wave according to claim 12, wherein the learning set is data in which a deviation occurs in the ST segment and the T wave in the CSE database (Common Standards for Quantitative Electrocardiography data base). Display method. The EKG signal of claim 3, wherein the maximum deviation is a value obtained by dividing an absolute value by a difference between a column vector of the first set of amplitudes and an average of the column vectors divided by a standard deviation of the column vectors. How to display properties for ST segments and T waves.