JPH0215210B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a body surface electrocardiograph for measuring cardiac electrical phenomena. In particular, this invention measures potentials from many points on the body surface near the heart, calculates the measured potentials, and displays a body surface potential distribution diagram for a certain time in order to clearly capture cardiac electrical phenomena. Regarding electrocardiographs.

[Prior art and its problems]

The electrocardiograph most commonly used today measures temporal potential changes at six points on the chest. This electrocardiograph displays time on the horizontal axis and potential on the vertical axis. With this type of electrocardiograph, the amount of information in the electrical signals measured from the electrodes is small, making it difficult to clearly examine all cardiac electrical phenomena. A body surface electrocardiograph has been developed as an electrocardiograph that measures a huge amount of electrical signals from the body surface near the heart. This body surface electrocardiograph is placed on the body surface near the heart.
For example, 80 to 200 electrodes are arranged. Cardiac potentials are collected from all of these electrodes and the electrical phenomena of the heart are judged comprehensively. As shown in FIG. 1, this body surface electrocardiograph creates a body surface potential distribution map near the heart at a certain time. This body surface potential distribution map displays the height of the body surface potential using equipotential lines. A body surface potential distribution map is created by temporarily storing the potential of each electrode at a certain time in a memory, calculating equipotential points using a computer based on the potential of each electrode, and creating equipotential lines, for example. Displayed on an XY plotter or monitor TV at a pitch of several tens of μV. This body surface electrocardiograph is used, for example, for several hundred microseconds to several meters.
Display multiple potential distribution maps at second intervals. Cardiac electrical phenomena are examined by looking at changes in this body surface potential distribution map. For example, when looking at a body surface potential distribution map, the expansion of positive or negative regions, contraction status, and changes in potential gradient are obvious. Display clearly. Electrodes for body surface electrocardiographs are required to have the following characteristics. It can accommodate body shapes that vary from person to person and between men and women. Measurement errors should not occur due to unevenness on the body surface or variations in unevenness due to breathing movements. Do not cause fear, pain, or pressure to the patient. To be able to be easily and quickly installed and removed, and to require no maintenance. Each electrode can be placed in a fixed position without relative displacement. The present inventor has developed an electrode shown in FIG. 2, which satisfies the above-mentioned characteristics. However, this electrode
The body surface potential changed depending on the measurement conditions during use. At first, we assumed that the changes in the body surface potential distribution map were due to the instability of the contact state of the electrodes, and although we tried various methods to improve the contact state of the electrodes, we were unable to prevent the fluctuations in the body surface potential distribution map. Ta. After that, as a result of numerous experiments and trial and error, he discovered that there are certain rules in the fluctuations of the body surface potential distribution map. That is, we discovered that many fluctuations in potential distribution occur at the open end portion of the shield case that constitutes the electrode, and we observed in detail the contact state of the electrodes when the potential distribution fluctuates. As a result, they finally discovered that the disturbance in the potential distribution causes the open end of the metal shield case to come into contact with the body surface, creating a short circuit on a part of the body surface. Therefore, it is an object of the present invention to provide a body surface electrocardiograph that does not disturb the electric potential due to the formation of short circuits on the body surface by the electrodes during measurement, and which can perform measurements simply and quickly.

[Means to solve conventional problems]

The body surface electrocardiograph of the present invention has the following configuration in order to achieve the above-mentioned object. A body surface electrocardiograph includes electrodes that touch multiple points on the skin surface of the human chest and detect the potential at the contact points;
An arithmetic circuit that processes the input signal of this electrode to calculate the potential distribution on the body surface over a certain period of time, and a monitor that displays a potential distribution diagram on the body surface based on the output signal of this arithmetic circuit. We are prepared. The electrode includes a metal shield case, a plurality of electrode rods that are attached to the shield case so as to be removable and removable, and an elastic body that elastically pushes the electrode rods out of the shield case. The shield case is made into a box shape with an opening on the side facing the body surface, and the opening edge of the box is insulated.

[Action, effect]

A plurality of electrode rods are provided in a metal shield case so that they can move in and out. The electrode rod provided in this state is shielded by the shield case, and induction of external noise is blocked. Therefore, the electrode rod can reduce the influence of noise and accurately measure cardiac potential in a low-noise state. Furthermore, since the opening edge of the shield case is insulated, the open end of the metal shield case does not come into contact with the body surface and disturb the potential distribution. Therefore, the body surface electrocardiograph of the present invention has the feature that the electrodes can accurately measure the potential induced from the heart and display a highly accurate body surface potential distribution map.

【Example】

Embodiments of the present invention will be described below based on the drawings. The body surface electrocardiograph shown in FIG. 3 includes an electrode 1, an arithmetic circuit 2, an operation switch 3, and an
and a monitor television 4'. The electrode 1, as shown in FIGS. 4 to 6,
It consists of ten main bodies 6 and eight electrode groups 5 attached to the main bodies 6. The ten main bodies 6 are also connected by a movable member 7 which is a string-like rubber elastic body. A stretchable wrapping band 8 is connected to the main body 6 located at the outermost side. An adhesive tape 9 is sewn to the tip of the wrapping band 8. As shown in FIG. 5, each main body 6 has a plurality of electrode rods 5N arranged side by side in a manner that they can move in and out. The main body 6 includes a box-shaped metal shield case 1 that is open downward, that is, on the side facing the body surface.
0 and two insulating boards, namely printed circuit boards 1
1, and a surface plate 12 from which an electrode rod 5N is projected outside the shield case. The electrode rod 5N is inserted through the printed circuit board 11 and the surface plate 12 so as to be freely removable and removable. A coil spring 13 through which an electrode rod 5N is inserted is disposed between the printed circuit board 11 and the surface plate 12. The outer surface, the entire lower surface in FIG. 5, of the surface plate 12 is non-conductive so that when the surface comes into contact with the body surface, it will not shoot a part of the body surface and disturb the potential distribution. The surface plate 12 is made of Bakelite, for example.
Either the entire body is made of synthetic resin such as epoxy, polyethylene, vinyl chloride, polystyrene, acrylic, or fluororesin, or a synthetic resin board is glued to the outer surface, or the surface plate is made of synthetic resin. By coating the outer surface, the entire surface can be made non-conductive. The surface plate 12 covers the entire opening edge of the shield case 10, as shown in FIG. The open end of the shield case 10 is fitted into a notch carved around the surface plate 12 and
It does not appear on the outer surface of 2. The shield case 10 is preferably made entirely of metal to shield the inside of the electrode. However, as shown in FIG. 7, the outer peripheral surface of the shield case made of the conductive film K may be made of a non-conductive material. The electrodes shown in FIGS. 5 and 6 are four electrode rods 5N arranged close to each other and measure the potential at one location on the body surface. That is, four electrode rods 5N constitute one electrode group. The shorter the interval between the electrode groups 5, the more accurately the potential distribution can be detected. However, this not only dramatically increases the number of electrode groups 5 and requires time to calculate equipotential lines, but also significantly increases the cost of the entire device. Therefore, the spacing between the electrode groups is usually determined to be between 5 mm and 9 cm, preferably between 1 cm. The coil spring 13 is a compression spring, and its lower end is located between the electrode rods 5N and its upper end is located between the upper printed circuit board 1.
1 and is connected to a conductive layer 14 such as a copper film printed on the upper surface. The main body 6 shown in FIGS. 6 and 8 includes eight electrode groups 5 in one main body 6. The four electrode rods 5N are arranged in parallel considerably closer to each other than the spacing between the electrode groups 5 of each set, for example, separated by a fraction of the distance between the electrode groups. The coil spring 13 inserted into the main electrode rod 5N is connected to the conductive layer 14 on the top surface of the printed circuit board. With this structure, even if any of the electrode rods 5N cannot contact the body surface, if any one of the electrode rods 5N comes into contact with the body surface, the body surface potential can be detected by that electrode rod. In this structure, for example, the interval between the electrode rods 5N is 1 to
15 mm, so even if the coil spring 13 pushes out the electrode rod 5N, the structure that transmits the detected potential of the electrode rod 5N to the leader wire 15 is such that each electrode rod 5N can move up and down freely without being influenced by each other. It has an ideal structure in terms of movement. The printed circuit board 11 has a cylinder 16 inserted into a through hole through which the electrode 5N is inserted. The cylinder 16 is made of stainless steel, copper, aluminum,
Alternatively, a metal cylindrical body, so as to reduce the frictional resistance with the electrode rod 5N, which is a metal wire such as a conductive alloy,
Alternatively, a cylindrical body with a smooth inner surface and low frictional resistance is used. Further, as shown in FIG. 7, this cylindrical body 16 protrudes somewhat downward from the lower end of the printed circuit board 11, and when the electrode rod 5N is pushed into this protruding portion, the coil spring 13 is pushed out and crushed. , the upper end of the coil spring 13 is inserted. Electrode rod 5 pushed out by coil spring 13
The lower end of the coil spring 13 is fixed by, for example, soldering or welding, and the thickened collar catches the through hole 17 of the lower surface plate 12, thereby preventing it from coming out. As shown in FIG. 8, the printed circuit board 11 is printed with a conductive layer 14 such as a copper film, and a lead wire 15 is connected to one end of the conductive layer 14. In the main body shown in FIG. 9, a coil spring 13 is disposed above the printed circuit board at the upper end of the electrode rod, and the electrode rod 5N is inserted through the coil spring. A coil spring is a tension spring.
The lower end is connected to the middle of the electrode rod, the upper end is welded to the conductive layer of the printed circuit board 11, and a lead wire is connected to the conductive layer. In the main body shown in FIG. 10, coil springs are arranged above and below the printed circuit board. According to this structure, one end of one or both of the upper and lower coil springs may be connected to the conductive layer of the printed circuit board, and a leader wire may be connected to the conductive layer. In this case, one of the coil springs may be made considerably softer, that is, the elastic modulus, which is the force required to extend a unit length, may be made considerably smaller. The main body 6 shown in FIG.
A set of electrode groups 5 are provided, and four needle electrodes 5H are provided at the tip of a rod R serving as an electrode rod. As shown in FIG. 12, the needle electrode 5H is inserted into a shaft hole axially penetrated through the base B at the tip of the rod R so that it can move parallel to the rod R. The needle electrode 5H is thick in the middle and has a flange, and the opening of the shaft hole H is narrowed somewhat.
A coil spring S, which is an elastic body that elastically pushes out the needle electrode 5H, is inserted into the shaft hole H. The coil spring S is a push spring inserted into the needle electrode 5H, and its lower end pushes the collar of the needle electrode 5H, and its upper end is pushed into the narrow opening of the shaft hole H. The coil spring S has conductivity, and both upper and lower ends are in electrical contact with the needle electrode 5H and the rod base B by their own elasticity or by being welded or soldered to the needle electrode 5H and the rod base B, The cardiac potential of the needle electrode 5H is transmitted to the rod R. In FIG. 13, a needle electrode 5H is inserted through a non-conductive base B. In FIG. This base B is made of a non-conductive material such as synthetic resin, and is fixed to the tip of the rod R. As shown in FIG. 14, the base B has shaft holes H passed through it at regular intervals in the axial direction, similar to the base B shown in FIG. 12, and the needle electrodes 5H are inserted into the shaft holes H.
The upper end of the coil spring S in the shaft hole H is electrically connected to the collar of the rod R. According to this structure, even if the lower end surface of the base B comes into contact with the body surface, the contact area will not increase compared to the state where the needle electrodes 5H are in contact with the body surface, and one set of needle electrodes 5
H can accurately detect local cardiac potential on the body surface in a narrow area. The surface plate 12 has a through hole P into which the needle electrode 5H can be inserted freely when the main body is pressed against the body surface.
is installed protrudingly. Similarly to the electrodes shown in FIG. 5 or 7, the electrode with this structure also has a structure in which the entire surface plate 12 is made of a non-conductive material, or even if there is a conductive part on the surface, its maximum length is 10 cm or less. Ru. Furthermore, the surface plate 12 must not electrically contact each set of needle electrodes 5H when pushed in. Therefore, even if a portion of the surface plate 12 is electrically conductive, this electrically conductive layer must not shorten each set of electrodes. Compared to the electrode shown in FIG. 5, the electrode with this structure makes it difficult for the outer surface of the surface plate 12 to come into contact with the body surface during measurement. It also happens that the surface of the body becomes uneven and makes contact. For the movable member 7 that connects each block, a non-stretchable string or band, or a flexible synthetic resin, etc. can be used. The lead wires 15 connected to the electrodes are collected into one shielded wire 18, and the shielded wire 18 is also connected to the arithmetic circuit 2. By the way, the potential detected at the electrode is quite low, and removal of external noise must be taken into consideration. This improves the S/N ratio by shielding each block independently. Furthermore,
In order to reduce the noise level, as shown in FIG. 15, it is preferable to incorporate amplification means for amplifying the signal detected by the electrodes, such as an amplifier for amplification, in the block. The main body, which has eight sets of electrode groups, incorporates eight sets of amplifiers, and can transmit a body surface detection potential signal to the arithmetic circuit 2 through the output signal leader line 15. The eight sets of amplifiers are preferably attached to the printed circuit board 11. FIG. 16 shows the state in which the electrode is attached to the human chest. That is, each main body 6 is placed on the body surface near the heart, and both ends of the wrapping band 8 are connected to each other with adhesive tape, so that the needle electrode 5H of the main body 6 is brought into contact with the body surface with a constant pressure. In this case, as shown in FIG. 16, the outside of the main body 6 may be further tightened with an elastic band 19 to press and contact the electrodes against the body surface with a stronger force. The arithmetic circuit 2 processes the electrical signals sent from the electrodes according to a predetermined method, calculates the equipotential line position at regular intervals, and outputs the output signal.
The data is sent to the XY plotter 4 and monitor television 4', and equipotential lines are drawn on these to create the potential distribution on the body surface.

[Brief explanation of drawings]

Fig. 1 is a body surface potential distribution diagram near the heart, Fig. 2 is a sectional view of a conventional electrode, Fig. 3 is a block diagram of a body surface electrocardiograph showing an embodiment of the present invention, and Fig. 4 is a diagram of the body surface potential distribution near the heart. 5 is a sectional view of the electrode showing one embodiment of the present invention; FIG. 6 is a bottom view of the electrode shown in FIG. 5; FIG. 7 is an enlarged sectional view of the main part of the electrode; The figure is a plan view of the printed circuit board, Figures 9 to 11 are cross-sectional views of electrodes showing another embodiment, and Figures 12 and 13 are
The figure is an enlarged cross-sectional view showing the tip of the electrode rod, Figure 14 is a bottom view of the tip of the electrode rod in Figure 13, Figure 15 is a schematic cross-sectional view of the electrode with a built-in amplifier, and Figure 16 is an example of how it is used. FIG. 1...Electrode, 2...Arithmetic circuit, 3...Operation switch, 4...XY switch, 4'...Monitor TV,
5... Electrode group, 5N... Electrode rod, 5H... Needle electrode, 6... Main body, 7... Movable member, 8... Winding band, 9... Adhesive tape, 10... Shield case, 11... Printed circuit board, 12... Surface plate, 13... Coil spring, 14... Conductive layer, 15... Lead wire, 16... Cylindrical body, 17...
Through hole, 18...shield wire, 19...band,
B... Base, K... Conductive wire, R... Rod, S...
...Spring coil, H...Shaft hole, P...Through hole.

Claims (1)

[Claims] 1. Contacting multiple locations on the skin surface of the human chest,
An electrode that detects the potential of the contact point, an arithmetic circuit that processes the input signal of this electrode to calculate the potential distribution on the body surface at a certain time, and an output signal of this arithmetic circuit that detects the potential distribution on the body surface. In a body surface electrocardiograph, which consists of a monitor that displays a potential distribution diagram, the electrodes consist of a metal shield case, a plurality of electrode rods that are attached to the shield case so as to be able to move in and out, and a monitor that displays a potential distribution diagram. The shield case is made into a box shape with an opening on the side facing the body surface, and the opening edge of the box is insulated. body surface electrocardiograph.