JPH057016B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an electrocardiogram analysis device that can be used for predicting and treating heart diseases.

Configuration of conventional examples and their problems In general, the heart acts as a biological pump and continues to contract and expand without rest. This is called mechanical activity of the heart, but there is actually an activity in the heart that causes this mechanical activity, and this is called electrical activity, and this electrical activity can be detected using an electrocardiograph. What I recorded using
This is an electrocardiogram waveform.

As shown in FIG. 1, the electrocardiogram waveform is mainly divided into P wave 1, Q wave 2, R wave 3, S wave 4, and T wave 5. First, the P wave 1 represents the atrial excitatory process in which an excitatory stimulus that begins at the sinus node 6 is transmitted to the atrioventricular node 8 through the intraatrial conduction fibers 7, as shown in FIG. The QRS wave group is Q wave 2, R wave 3,
The three waves of the S wave 4 are collectively called the S wave 4, in which the excitation passes through the atrioventricular node 8, the His bundle 9 in the upper part of the ventricle, the left leg posterior line 10 first branches,
The fibers further divide into the left anterior leg line 11 and the right anterior leg line 12, become Purkinje fibers 13, run on the surface of the endocardium, and spread throughout the ventricular muscle 14 until the end of the cardiac excitation process. It represents. That is, Q wave 2 represents the excitation process of the ventricular septum, R wave 3 represents the excitation process of the ventricular muscle, and S wave 4 represents the excitation process of the ventricular muscle on the opposite side as viewed from the electrode position. In other words, the QRS wave complex represents the excitation process of the ventricular septum and left and right ventricular muscles. Ventricular contractile activity occurs after the electrical impulses, which appear as QRS complexes, pass through. The recovery process of the ventricular muscle 14 also appears as a T wave 5.

Furthermore, if we look at the principle of electrocardiogram waveform generation from a microscopic perspective, the excitement of the sinus node 6, which is a collection of pacing cells, causes a change in the intracellular potential of each cell in the transmission path (generation of an action potential), and The applied potential is observed to be attenuated to about 1/1000 of its value. The waveform that appears on an electrocardiograph can be said to be a vector representation of the activity of cells on the excitation transmission path within the heart.

For example, for the sake of simplicity, if we consider only one transmission path hypothetically, as shown in Figure 3, in the transmission from the atrioventricular node 8 to the Purkinje fibers 13 and the ventricular muscle 14, the cells that constitute each The action potentials within each are slightly different, namely the fourth action potential.
Figure a shows the atrioventricular node, Figure 4b shows the bundle of His, Figure 4c shows the right leg, Figure 4d shows the Purkinje fibers, and Figure 4e shows the action potentials of the ventricular muscle, and these are slightly different. There is. If A, B, C, D, E, F on the transmission path
If you look at the intracellular potential at a point on the time axis, it will be as shown in Figure 5.The electrodes on the human body surface will be attenuated to about 1/100, and the voltage axis will be different as shown in Figure 6. It is expressed as the integrated value of the intracellular potential over time.
In reality, there are many cells from the atrioventricular node 8 to the ventricular muscle 14, and in the transmission of excitement, the observed waveform of the intracellular potential on the human body surface is similar to that of an electrocardiogram, as shown in Figure 7.
It is thought to appear as QRS complexes.

If there is a disease in the above excitement transmission pathway and the cell action potential is not normal, QRS
As shown in Fig. 8, the waveform has a concave portion and differs from the normal waveform.

Conventional electrocardiographs mainly record with a pen recorder, but there are limitations such as the material of the paper and the mechanical movement of the pen, and it is usually not possible to follow a waveform of about 100Hz, so changes in the waveform can be detected. It is difficult to see, and even if an electromagnetic oscillograph is used, it can only track waveforms of 2 to 3 kHz, and diseases in the excitation transmission pathway can only be detected in large areas of about 30 to 40 mm. There was a problem that the detection of the disease was delayed and the mortality rate could not be lowered.

Purpose of the Invention The present invention has been made to eliminate the above-mentioned conventional problems, and has the ability to discover diseased areas on the electrical stimulation (excitation) transmission path of the source of cardiac activity, which was previously undetectable. It is an object of the present invention to provide an electrocardiogram analysis device that can estimate the location of a diseased region with higher accuracy.

Structure of the Invention In order to achieve the above object, the present invention includes an amplifier that amplifies analog minute biological signals obtained from electrodes attached to the surface of the human body, and an A/D that converts the analog signal amplified by the amplifier into a digital signal.
a converter, a delay circuit that creates a trigger point using the analog signal amplified by the amplifier, and stops storage in the external storage section after a certain delay time based on this trigger point; A CPU that stores digital signals before and after the trigger point in an external storage unit, and a CRT display that processes and displays digital time for all or part of the time stored in the external storage unit by the CPU. According to this configuration, the conversion speed of the A/D converter,
By making the so-called sampling time extremely small, the waveform corresponding to the QRS wave part of an electrocardiogram can be broken down into small pieces on both the time and voltage axes of the electrocardiogram, making it possible to detect minute changes in the electrocardiogram extremely easily and accurately. It is something that can be observed. In addition, since the waveform once captured is stored in the external storage unit, the waveform once stored can be displayed on the CRT display as many times as necessary, and even if it is in an arbitrary interval, it can be displayed on the CRT display. Since the display can be displayed according to the current situation, it is now possible to enlarge the whole or a part, and as a result, minute changes in waveforms that cannot be observed with conventional electrocardiographs can be observed, making it possible to predict and treat heart diseases. It is of great help.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 9 shows a block diagram of an electrocardiogram analyzer according to an embodiment of the present invention. Reference numeral 21 represents a human body, with a total of four sensors, one each in each limb of the human body 21, namely, one in each hand and each foot, and six in the chest. The main electrode 22 is fixed, and the lead selector 23 selects one of the six limb leads or the six chest leads. In this case, the biosignal induced from the human body 21 is very small, only about 1 mV, so the amplifier 24 amplifies the biosignal. The biological amplification section 24 performs these operations.

The amplified signal is an analog signal, and in order to process it in the CPU, the A/D converter 2
5 to convert it into a digital signal. On the other hand, when the memory start switch is pressed, the amplified signal is compared with a preset trigger voltage by the voltage comparator 26, and the trigger point is detected. Further, the external storage section 27 has a capacity for a certain period of time (0.1 to 0.4 seconds), and the external storage section 27 is always shifted and stored in chronological order until a storage start signal is input.

In this state, when the aforementioned memory start switch is pressed, after the trigger point is detected, the delay device 28
After a predetermined period of time has elapsed, digital signal capture is stopped. The delay time of the delay device 28 is
By making the storage time shorter than the storage time determined by the capacity of the external storage section 27, digital signals before the trigger point are also stored.

When observing the stored electrocardiogram waveform, the digital signal from the external storage section 27 is transferred to the CPU 2.
9, and convert it to an analog signal,
It is displayed on the CRT display 30 as a two-dimensional figure with a time axis and a voltage axis. Furthermore, it becomes possible to extract any point or section from the external storage section 27 and observe it under magnification.

By setting the conversion speed, so-called sampling time, of the A/D converter 25 that converts the analog signal into a digital signal to, for example, 20 μsec,
Approximately 0.1 seconds of waveform, which corresponds to the QRS wave portion of an electrocardiogram, can be broken down and converted into 5000 points on the time axis.
Furthermore, by decomposing the A/D converter 25 into the voltage axis, for example, into 12 binary bits, the maximum voltage of the QRS wave part is approximately 1.0 to 1.1 mV, so if the maximum converted voltage is 1.5 mV, It will have a resolution of 0.37μV.

In this way, in one embodiment of the present invention, the QRS wave part of the electrocardiogram is divided into 5000 points (at 20 μsec intervals) on the time axis.
It can be resolved into 0.37 μV on the voltage axis,
This makes it possible to observe minute changes in waveforms that could not be detected with conventional electrocardiographs.

Effects of the Invention As described above, according to the present invention, the conversion speed of the A/D converter that converts the analog signal amplified by the amplifier that amplifies the analog minute biological signal obtained from the electrode attached to the human body surface into a digital signal. By making the so-called sampling time extremely small, the waveform corresponding to the QRS wave part of an electrocardiogram can be finely resolved in both the time and voltage axes of the electrocardiogram, making it extremely easy to detect minute changes in the electrocardiogram. can be observed accurately.
Further, data before the trigger point can be easily stored due to the delay time of the delay circuit, and waveforms before the trigger point can also be stored in detail. In addition, since the waveform once captured is stored in the external storage, the waveform once stored can be displayed on the CRT display as many times as necessary.
Moreover, since any section can be displayed as needed, it is now possible to enlarge the whole or a portion, and as a result, it is possible to observe minute changes in waveforms that could not be observed with conventional electrocardiographs. This makes it extremely useful for predicting and treating heart disease.

[Brief explanation of the drawing]

Figure 1 is a conventional electrocardiogram waveform diagram, Figure 2 is a vertical cross section of the heart and a model of the electrical impulse transmission path, and Figure 3 is a cross section of the interventricular septum and right ventricle of the heart and a model of the electrical impulse transmission path. , Fig. 4 a, b, c, d, and e are waveform diagrams of the intracellular potential at each point on the electrical stimulation transmission path, and Fig. 5 is a superposition of the time axis and voltage axis of the intracellular potential on the electrical stimulation transmission path. Waveform diagram, Figure 6 is a waveform diagram of the electric potential observed on the human body surface, Figure 7 is a waveform diagram of the QRS wave observed on the human body surface, and Figure 8 is a waveform diagram of the QRS wave observed on the human body surface with heart disease. QRS waveform diagram,
FIG. 9 is a block diagram of an electrocardiogram analyzer showing an embodiment of the present invention. 22... Electrode, 24... Amplifier, 25... A/
D converter, 26...voltage comparator, 27...external storage section, 29...CPU, 30...CRT display.

Claims (1)

[Claims] 1. An amplifier that amplifies analog minute biological signals obtained from electrodes attached to the surface of the human body, an A/D converter that converts the analog signals amplified by the amplifier into digital signals, and an A/D converter that converts the analog signals amplified by the amplifier into digital signals. A delay circuit that creates a trigger point and stops storing it in the external storage after a certain delay time based on this trigger point, and a delay circuit that sends digital signals before and after the trigger point to the external storage. A CPU to remember and
An electrocardiogram analysis device comprising a CRT display that processes and displays digital time of all or part of the time stored in the external storage section using a CPU.