JP2004166934A - Body surface electrocardiograph - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To generate a potential distribution map with high precision by correctly detecting cardiac potential from multiple measurement parts, while reducing the change of an OV line with a simple configuration. <P>SOLUTION: A body surface electrocardiograph detects cardiac potential induced onto a body surface through the use of electrodes 1, and displays a body surface potential distribution map. The electrodes 1 includes a rod electrode 10 comprising: a plurality of conductive rods 12 to be pressed against a plurality of places on the body surface; electrode bodies 13 mounted to allow the conductive rods 12 to be put in/out; and elastic protrusion members 14, to protrude the conductive rods 12. Each conductive rod 12 includes: a rod part 12B; and a contact electrode 12A which is connected to the tip end part of the rod part 12B and brought into contact with the body surface. The outer shape of the contact surface 12a of the contact electrode 12A to be brought into contact with the body surface is larger than the cross section of the rod part 12B. The area of each contact surface 12a is larger than 15mm<SP>2</SP>, and smaller than the square (d/2)<SP>2</SP>of the half of an interval (d) between the centers of the adjacent contact electrodes 12A. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention measures the cardiac potential from many points on the body surface close to the heart in order to clearly understand the cardiac electrical phenomenon, and calculates the measured cardiac potential to display a body surface potential diagram at a certain time. Related to electric meter.
[0002]
[Prior art]
The body surface electrocardiograph is provided with a plurality of electrodes at 100 to 500 points on the body surface close to the heart, and simultaneously collects cardiac potentials from all the electrodes. A body surface potential distribution map for determining an electric phenomenon is created.
[0003]
The body surface electrocardiograph creates a potential distribution map induced on the body surface near the heart at a certain time, for example, as shown in FIG. The potential distribution diagram is a distribution diagram of the potential on the body surface in the cardiac electrical phenomenon. The potential distribution map is obtained by calculating with an arithmetic circuit such as a computer based on the cardiac potential signals measured at all the electrodes. That is, a cardiac potential detected by each electrode at a certain time is stored in a memory of a computer, and equipotential lines are calculated based on the cardiac potential of each electrode. Is displayed on a monitor television or a printer.
[0004]
The body surface electrocardiograph having this structure can inspect the electrical phenomena of the heart more precisely than a conventional electrocardiograph. However, since a body surface electrocardiograph needs to detect cardiac potentials from many electrodes simultaneously, it is extremely difficult to accurately and stably detect cardiac potentials from all electrodes. This is because it is difficult to bring all the electrodes into stable contact with the body surface in an electrically low-resistance state.
[0005]
Currently available body surface electrocardiographs apply a conductive paste to the skin to reduce the contact resistance between the electrode and the body surface. The conductive paste is interposed between the electrode and the body surface to reduce the contact resistance between the electrode and the body surface. The electrode of this structure can detect a cardiac potential induced on the body surface in a low resistance state as long as it can be normally adhered to the body surface. However, it is actually very difficult to adhere all the electrodes consisting of 100 or more to the body surface without peeling off, and if any of the electrodes peels off from the body surface, it becomes impossible to accurately detect the cardiac potential. Further, this electrode has a drawback that the running cost when measuring the electrocardiogram of one patient is extremely high because all the electrodes of 100 or more are disposable.
[0006]
As an electrode that solves such a defect, an electrode that elastically presses a metal rod against a body surface has been developed. This electrode detects a cardiac potential induced on the body surface by independently pressing the metal rod against the body surface. This electrode can detect a cardiac potential without using a conductive paste. When the metal rod is continuously pressed against the body surface, a conductive liquid such as sweat is interposed between the metal rod and the body surface, and the metal rod as an electrode is electrically connected to the body surface. This is because the contact is made. The electrodes that are pressed against the body surface are electrically connected via a small amount of conductive liquid that appears on the surface of the skin. The human skin has sweat glands, from which sweat, which is a conductive liquid, is seeping out. However, the surface of the human skin is not evenly seeped by the conductive liquid. A large amount of the conductive liquid is present in the vicinity of the sweat glands, and the amount of the conductive liquid is small in a portion away from the sweat glands. For this reason, the contact resistance of the skin surface varies depending on the portion where the metal rod contacts. The variation in the partial contact resistance of the skin is extremely large and varies on the order of magnitude.
[0007]
For this reason, when a plurality of metal rods are pressed as electrodes on a local part of the body surface, some electrodes are electrically connected to the body surface with low contact resistance, but some electrodes come into contact with the body surface with extremely high contact resistance. . Electrodes that contact the body surface with high contact resistance cannot accurately detect the cardiac potential induced on the body surface. When the contact resistance between the electrode and the body surface is sufficiently low compared to the input impedance of the first-stage amplifier that amplifies the cardiac potential, the contact resistance does not cause a cardiac potential detection error. However, if the contact resistance becomes too large to be neglected with respect to the input impedance of the first-stage amplifier, an error occurs in detecting a cardiac potential. This is because the input impedance of the first-stage amplifier attenuates the cardiac potential induced at the electrodes. For example, when the contact resistance between the electrode and the body surface becomes 1/10 of the input impedance of the first-stage amplifier, the cardiac potential induced at the electrode is attenuated by 10% and input to the first-stage amplifier. For this reason, the cardiac potential detected by the electrode is reduced to 90%, and it becomes impossible to accurately detect the cardiac potential. The first-stage amplifier is designed so that the input impedance is as large as possible. However, if the contact resistance is large, the first stage amplifier may not be sufficiently large with respect to the contact resistance. Depending on the contact part, the contact resistance between the electrode and the body surface fluctuates on the order of an order of magnitude. Therefore, depending on the contact part, the contact resistance of the electrode may be larger than several tens of% of the input impedance of the first-stage amplifier. In this state, the substantial input voltage of the first-stage amplifier becomes lower than the accurate cardiac potential, and an accurate potential distribution diagram cannot be created.
[0008]
Further, a local battery generated between the electrode and the body surface is a factor that makes it difficult for the metal rod as the electrode to accurately detect the cardiac potential on the body surface. Unfortunately, the voltage generated by the local battery is much higher than the cardiac potential. Since a battery in which a metal comes into contact with a conductive liquid is formed, generation of a local battery in a contact portion cannot be eliminated in principle as long as a metal electrode is brought into contact with a body surface. The generated voltage of the local battery is specified by the material of the metal rod and the conductive liquid. Therefore, the voltage of the local battery varies depending on the material of the metal rod. For example, when stainless steel is used as the electrode metal, the voltage of the local battery becomes extremely large, several hundred mV. Since the local battery is a DC voltage, it can be separated from the cardiac potential unless it changes. However, it is actually extremely difficult to always keep the generated voltage of the local battery constant. Since the voltage of the local battery is extremely large, several tens to hundred times as large as the cardiac potential, a slight voltage change of the local battery causes a 0V line of the cardiac potential to fluctuate, resulting in a detection error. This is because if the generated voltage of the local battery fluctuates and the 0V line fluctuates, it cannot be recognized as a change in cardiac potential. If the voltage fluctuation of the local battery is sufficiently slow as compared with the voltage fluctuation of the cardiac potential, it can be removed by a low cut filter that removes extremely low frequency components. The low cut filter is designed so that the cutoff frequency is sufficiently lower than the lowest frequency component included in the cardiac potential so as not to attenuate the cardiac potential. When the fluctuation of the 0V line becomes faster to a frequency close to the cardiac potential, this low cut filter passes the line without being cut off. For this reason, such a fluctuation of the 0 V line cannot be separated from the cardiac potential, resulting in a measurement error. For this reason, it is extremely important how the local battery generated between the electrode and the body surface can be kept constant without changing its voltage.
[0009]
Fluctuation of the 0V line by the local battery is caused by a conductive liquid such as sweat that appears on the body surface. Since this liquid reduces the contact resistance between the electrode and the body surface, without it, the cardiac potential cannot be detected even if the metal rod is pressed against the body surface. Thus, the conductive liquid that oozes out on the body surface reduces the contact resistance of the electrodes and enables accurate detection of the cardiac potential, but also causes the generation of a local battery and disrupts the 0V line. That is, although a conductive liquid is required, the presence thereof causes the 0V line to fluctuate, making it difficult to detect the cardiac potential. This makes it extremely difficult to accurately detect cardiac potentials induced on the body surface. This state is also apparent from the fact that it becomes extremely difficult to accurately detect the electrocardiographic potential when, for example, after a large amount of sweat has been dried and the concentration of the sweat has increased to a high level. When the concentration of sweat increases, the phenomenon of the local battery becomes severe, and the fluctuation of the 0V line becomes so severe that the cardiac potential cannot be detected. To further complicate matters, reducing the fluctuation of the 0 V line caused by the local battery and reducing the measurement error by reducing the contact resistance of the electrode are close to the limit of whether measurement is possible. Therefore, in a state where many electrodes are pressed against the body surface, the contact resistance between the electrodes and the body surface is reduced while the 0 V line fluctuation of the cardiac potential detected by all the electrodes is negligibly small. It is extremely difficult to make it sufficiently lower than the impedance. Therefore, it is very difficult to accurately detect the cardiac potential from all the electrodes by pressing the body surface with a large number of electrodes.
[0010]
Further, since the body surface electrocardiograph detects cardiac potentials at a large number of sites at 100 or more, a highly accurate body surface potential distribution map cannot be created unless the cardiac potentials can be accurately detected from all the sites. As the number of electrodes increases, it becomes rapidly difficult to accurately detect the cardiac potential simultaneously from all the electrodes. In this type of body surface electrocardiograph, it is extremely important to keep the contact state of the electrodes low and stable while limiting the fluctuation of the 0V line of all the electrodes, even though there are many electrodes. If this cannot be achieved, a body surface electrocardiograph that creates a highly accurate potential distribution map cannot be put to practical use. A body surface electrocardiograph in which one of the electrodes is always unstable cannot accurately detect an electric potential distribution map forever because there is an area that cannot be detected accurately.
[0011]
In order to solve this problem, a body surface electrocardiograph that is currently in practical use applies a conductive paste to the body surface, and electrically contacts the electrode to the body surface with the conductive paste. However, a body surface electrocardiograph having this structure cannot be used for diagnosis of a large number of patients, such as a health check, because the running cost is too high. Incidentally, the current body surface electrocardiograph has an insurance score of 1500 points, and the examination cost using insurance is extremely high at 15,000 yen. Furthermore, it takes time to measure one patient, which makes it difficult to use in medical examinations and the like. This is because a body surface potential distribution map is created by mounting 100 or more electrodes on the body surface via the conductive paste at specified positions of the patient. In this method, the measurement time of one patient cannot be shortened. This also makes the use of medical examinations difficult. Although it is not limited to testing for heart disease, it is important to detect all diseases as early as possible, so how to use a surface electrocardiograph at low cost, faster, and more accurately. It is particularly important that the potential distribution map can be measured in advance.
[0012]
For the purpose of solving this problem, a body surface electrocardiograph that uses a plurality of needle electrodes to measure a single cardiac potential has been developed (see Patent Document 1). In this body surface electrocardiograph, four needle electrodes are connected in parallel, and each is independently pressed against the body surface. Since the electrodes connect the needle electrodes in parallel, if one of the needle electrodes detects the cardiac potential on the body surface, the cardiac potential can be measured even if the other needle electrodes cannot accurately detect the cardiac potential. Therefore, the cardiac potential can be detected more stably than an electrode that presses one metal rod against the body surface.
[0013]
[Patent Document 1]
Japanese Patent Publication No. 2-9811
[0014]
[Problems to be solved by the invention]
However, this electrode has a disadvantage that the structure is complicated and the manufacturing cost is high. Furthermore, as a result of actually manufacturing this electrode and detecting cardiac potentials of a large number of patients, it was found that it was difficult to suppress the fluctuation of the 0 V line to an ideal state with this structure. When detecting 100 or more cardiac potentials, the 0V line of any electrode fluctuates, and it takes time to accurately detect the cardiac potential from all the cardiac potentials.
[0015]
A great deal of experiments were repeated to find out this phenomenon, but the cause of the 0V line fluctuation could not be found. Even if electrodes of various structures were prototyped and pressed against the body surface, and a conductive paste was applied to the body surface to detect the cardiac potential, the fluctuation of the 0V line could not be reduced. Furthermore, as a result of repeating an enormous amount of experiments, it was determined that the cause of the fluctuation of the 0 V line was a relative movement between the needle electrode and the body surface. The patient measuring the cardiac potential breathes, so that the body surface moves up and down. When the body surface moves up and down due to breathing, the electrodes and the body surface move relatively to change the 0V line. When the breathing was stopped and the cardiac potential was detected, the fluctuation of the 0V line was reduced. However, when breathing is stopped, the patient gradually becomes tense and myoelectric potential is induced on the body surface. The myoelectric potential induced on the body surface is not a sufficiently small voltage compared to the cardiac potential, and is a signal that fluctuates irregularly. Therefore, when this occurs, it causes the cardiac potential to be disrupted. Furthermore, even if breathing was stopped, the fluctuation of the 0V line of the electrode could not be reduced to a desirable state. As a result of observing the movements of the electrodes and the body surface more closely in order to find out the cause, the body surface slightly moved due to the heartbeat, and the inability of the needle electrode to follow this movement may also cause the 0V line to be out of order. I decided to become.
[0016]
If the relative movement between the electrode and the body surface causes the 0V line to fluctuate, it can be solved by moving the needle electrode smoothly. In order to realize this, in order to reduce the sliding resistance between the needle electrode and the portion holding the needle electrode, a trial production of an electrode was made using Teflon (registered trademark) resin or the like. However, even if the sliding resistance of the needle electrode is designed to be as small as possible, this cannot be completely eliminated. The reason why the needle electrode moves relative to the body surface is that the needle electrode moves while receiving frictional resistance. Also, the surface of the skin, which is the body surface, has cushioning properties. When the body surface moves up and down, the needle electrode first experiences a large maximum frictional resistance, and when it moves, it becomes a kinetic frictional resistance and becomes smaller than the maximum frictional resistance. That is, the frictional resistance of the needle electrode is large at the start of the movement of the needle electrode, and is small at the start of the movement and fluctuates. Further, since the skin has a cushioning property, the body surface is in a state of pressing the needle electrode via the cushion. When the body surface moves up and down, the needle electrode in this state does not move up and down together with the body surface, but moves stepwise by repeatedly moving and stopping. When the needle electrode is pushed against the body surface and exceeds the maximum frictional resistance, the needle electrode starts moving, and when it moves, it moves largely due to a small dynamic frictional resistance and stops. Thereafter, this operation is repeated, and the movement and the stop are repeated. This state becomes more severe as the frictional resistance of the needle electrode increases.
[0017]
The present invention has been developed for the purpose of further eliminating this adverse effect. An important object of the present invention is to provide a body surface electrocardiograph which has a simple structure and can accurately detect cardiac potentials from a large number of measurement sites and create a highly accurate potential distribution map while reducing fluctuations of the 0 V line. To provide
Another important object of the present invention is to provide a body surface electrocardiograph capable of making an examination cost of one patient extremely low, and also making a measurement time short to quickly create a potential distribution map. .
[0018]
[Means for Solving the Problems]
The body surface electrocardiograph of the present invention includes an electrode 1 for detecting a cardiac potential induced on the body surface by being elastically pressed independently at a plurality of locations on the body surface of a patient, and a heart detected by the electrode 1. A calculation display unit 2 for displaying a body surface potential distribution map induced on the body surface from the potential. The electrode 1 includes a plurality of conductive rods 12 pressed against a plurality of locations on the body surface of a patient, an electrode body 13 mounted so that the conductive rod 12 can be moved in and out, and a conductive rod 12 elastically mounted on the electrode body 13. And a rod electrode 10 having an elastic extruded material 14 which is extruded in a desired manner. The conductive rod 12 is connected to a rod portion 12B so as to be able to enter and exit the electrode body 13, and is connected to a tip portion of the rod portion 12B to detect a cardiac potential induced on the body surface by contacting the body surface. And a contact electrode 12A. Further, the contact surface 12a that contacts the body surface of the contact electrode 12A has an outer shape larger than the cross section of the rod portion 12B, and has an area of 15 mm. ² And a square (d / 2) of the center distance (d) between the adjacent contact electrodes 12A. ² Smaller than. However, in this specification, the area of the contact surface 12a of the contact electrode 12A means a plane projection area of the contact electrode 12A as viewed from the body surface side.
[0019]
The conductive rod 12 has a circular cross-sectional shape of the rod portion 12B and an outer shape of the contact surface 12a of the contact electrode 12A. The outer diameter of the contact surface 12a is 2 to 15 times, preferably 3 to 8 times the diameter of the rod portion 12B. It can be. In the conductive rod 12, the outer diameter of the rod portion 12B can be 1.5 to 6 mm, and the outer diameter of the contact surface 12a can be 4 to 20 mm. The conductive rod 12 can be a metal rod.
[0020]
The contact electrode 12A can be any of stainless steel, Shinchu, lead, silver, and silver chloride. The contact electrode 12A can be provided with a metal plating layer on the surface of the contact surface 12a. The metal plating layer of the contact surface 12a can be any of gold, platinum, silver, silver chloride, nickel, chrome, cinchu, and lead.
[0021]
The contact surface 12a of the contact electrode 12A can be a curved surface that curves to the center. The curved surface of the contact surface 12a can make the radius of curvature of the peripheral edge smaller than that of the central portion. The radius of curvature of the central portion of the contact surface 12a, which is a curved surface, can be 10 to 100 mm. The radius of curvature of the periphery of the contact surface 12a, which is a curved surface, can be 1 to 20 mm.
[0022]
The rod electrode 10 can be composed of a plurality of electrode units 11. The plurality of electrode units 11 can be connected by the movable member 15.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiments described below exemplify a body surface electrocardiograph for embodying the technical idea of the present invention, and the present invention does not specify the body surface electrocardiograph as follows.
[0024]
Further, in this specification, in order to make it easy to understand the claims, the numbers corresponding to the members shown in the embodiments are referred to as "claims" and "means for solving the problem". Are added to the members indicated by "." However, the members described in the claims are not limited to the members of the embodiments.
[0025]
2 to 4 show a body surface electrocardiograph according to an embodiment of the present invention. The body surface electrocardiograph shown in these figures is provided with an electrode 1 for detecting cardiac potentials induced at a plurality of locations on a patient's body surface, and a cardiac voltage induced on the electrode 1 is calculated and guided on the body surface. And a calculation display unit 2 for displaying a body surface potential distribution map.
[0026]
As shown in FIGS. 3 and 4, the electrode 1 includes a lower electrode 1B disposed on the upper surface of the bed 3 and in contact with the lower surface of the body surface of the patient, an upper electrode 1A in contact with the upper surface of the patient, And a body-side electrode 1C that comes into contact with the body side. The lower electrode 1 </ b> B is disposed in a region opposed to almost the entirety of the lower surface of the patient's body surface from 60% or more. The upper electrode 1A is also provided in a region facing more than 60% of the upper surface of the body surface and almost entirely. The body-side electrode 1C is disposed so as to face the body under the armpit. When the patient lies upward on the bed 3 to detect a cardiac potential on the body surface, the lower electrode 1B contacts the patient's back, the body electrode 1C contacts the body side, and the upper electrode 1A contacts the patient's chest. To detect the cardiac potential induced on the body surface. When the patient is turned upside down and lies down on the bed 3, the lower electrode 1B contacts the patient's chest and the upper electrode 1A contacts the patient's back.
[0027]
In the body surface electrocardiograph shown in the figure, the upper electrode 1A is a rod electrode 10 for pressing a metal rod as the conductive rod 12 against the body surface, and the lower electrode 1B and the body-side electrode 1C are cushion electrodes 20. In a body surface electrocardiograph, only a body-side electrode can be a rod electrode, or an upper electrode and a body-side electrode, or an upper electrode and a lower electrode can be a rod electrode. Furthermore, all of the upper electrode, the lower electrode, and the body-side electrode may be rod electrodes. Further, the body surface electrocardiograph may be a single rod electrode without necessarily separating the electrodes into a lower electrode, a body electrode, and an upper electrode.
[0028]
The rod electrode 10 is composed of a plurality of electrode units 11, as shown in FIGS. The rod electrode 10 shown in these figures includes eight electrode units 11. The eight electrode units 11 are arranged four by two in two rows. As shown in the front view of FIG. 5 and the bottom view of FIG. 6, the electrode units 11 are connected by a movable member 15 which is a string-like rubber-like elastic body. As described above, the rod electrode 10 including the plurality of electrode units 11 has a structure in which the posture of each electrode unit 11 can be individually changed, and the plurality of conductive rods 12 can ideally contact the chest of the patient. This is because the lower surface of each electrode unit 11 can be arranged in a posture along the patient's chest.
[0029]
Further, in the rod electrode 10 shown in FIGS. 5 and 6, an elastic deformation plate 16 is fixed to the lower surface of the electrode units 11 in each row, and the four electrode units 11 are connected by the elastic deformation plate 16. The elastic deformation plate 16 is a plate or sheet having elasticity in the bending direction, for example, a rubber plate or a synthetic resin plate. This elastically deformable plate 16 has a feature that the posture of each electrode unit 11 can be arranged along the patient's chest while maintaining the interval between the adjacent electrode units 11 at a predetermined interval. Further, the elastic deformation plate 16 also has a function of preventing the electrode units 11 on both sides from tipping over in a state in which the electrode units 11 located on both right and left sides are inclined in the directions indicated by arrows in FIG.
[0030]
As shown in FIGS. 7 and 8, each of the electrode units 11 has a plurality of conductive rods 12 pressed against a plurality of positions on the patient's body surface, and is mounted so that these conductive rods 12 can enter and exit. It has an electrode body 13 and an elastic extruded member 14 that elastically pushes the conductive rod 12 from the electrode body 13.
[0031]
The electrode unit 11 shown in FIGS. 5 to 8 includes eight conductive rods 12. The eight conductive rods 12 are arranged in four rows in two rows on the electrode unit 11 having a rectangular bottom surface. These conductive rods 12 are arranged at equal center intervals (d). The center distance (d) between the conductive rods 12 is determined by the area of the region to be measured and the number of the conductive rods 12, that is, the number of points to be measured. The rod electrode 10 shown in the figure has 64 conductive rods 12 as a whole since eight conductive rods 12 are arranged in eight electrode units 11. This rod electrode 10 is, for example, approximately 600 cm ² Region can be measured. However, for the rod electrode, the number of electrode units is set to 2 to 64, the number of conductive rods, that is, the number of measurement points is set to 25 to 500, and the measurement area is set to 200 to 900 cm. ² And the center interval can be 10 to 60 mm. For example, when the number of rod electrodes is 15 × 3 × 5, the number of conductive rods is 225 × 15 × 15, and the center distance between the conductive rods is 20 mm, the length is about 800 cm. ² Region can be measured.
[0032]
Further, in the rod electrode, it is not necessary to make all the center intervals (d) of the plurality of conductive rods arranged equal. In the rod electrode, the center distance between the conductive rods can be changed in the vertical direction and the horizontal direction of the patient, or can be partially changed.
[0033]
The plurality of conductive rods 12 elastically protrude from the electrode body 13 toward the body surface, and independently press the body surface of the patient. These conductive rods 12 are connected to a rod portion 12B so as to be able to move in and out of the electrode body 13, and are connected to a tip portion of the rod portion 12B to contact a body surface and induce a cardiac potential induced on the body surface. And a contact electrode 12A to be detected. In the illustrated conductive rod 12, the rod portion 12B is a metal rod. The rod portion 12B is a metal wire having a diameter of 1.5 to 6 mm, preferably 3 to 4 mm. If the rod portion 12B is too thin, it will bend easily, and if it is too thick, the sliding resistance will increase and it will be difficult to smoothly move in and out. For the rod portion 12B, a hard-to-bend metal wire such as a stainless steel wire such as SUS304 or a piano wire whose surface is plated is suitable. Further, the rod portion can be made cylindrical and light. However, the rod portion does not necessarily need to be a metal rod. For example, a hard plastic rod having a conductive film coated on the surface or inner surface thereof, or a conductive carbon fiber formed into a rod shape may be used. it can. The rod portion 12B is mounted on the electrode body 13 so as to be movable in the axial direction, and is pressed toward the body surface by the elastic extruded material 14.
[0034]
The contact electrode 12A is made of metal and is elastically pressed against the body surface to detect a cardiac potential induced on the body surface. The contact electrode 12A is manufactured by cutting, casting, or pressing a metal. The metal contact electrode 12A can be formed of a metal such as stainless steel, Shinchu, lead, silver, silver chloride, or the like. In particular, the contact electrode 12A formed of a metal such as stainless steel, Shinchu or lead has a feature that it is hard to rust. Furthermore, since the contact electrode 12A made entirely of metal can increase the load on the rod 12B, the center of gravity of the conductive rod 12 can approach the center of gravity of the contact electrode 12A. In particular, when the conductive rod 12 is used for the upper electrode 1A, the conductive rod 12 can have a low center of gravity, and thus has a feature that the contact electrode 12A can be stably pressed against the surface of the body. Further, the metal contact electrode 12A may be provided with a metal plating layer on the surface or the entire surface of the contact surface 12a in order to stably detect the cardiac potential. As the metal plating layer, gold plating, platinum plating, silver plating, silver chloride plating, nickel plating, chrome plating, sinchu plating, lead plating, or the like can be used. Gold plating and platinum plating have the feature that they can stably and electrically contact the body surface. Silver plating and silver chloride plating can stably and electrically contact the body surface with low resistance. Nickel plating and chrome plating can also stably contact the body surface. Shinchu plating and lead plating can effectively prevent the surface from rusting.
[0035]
The size and shape of the contact surface 12a of the contact electrode 12A is important for stably detecting the cardiac potential. The contact electrode 12A has a contact surface 12a that comes into contact with the body surface having an outer shape larger than the cross section of the rod portion 12B. The contact electrode 12A has an area of the contact surface 12a of 15 mm. ² And a square (d / 2) of the center distance (d) between the adjacent contact electrodes 12A. ² Smaller than. In the illustrated contact electrode 12A, the contact surface 12a that contacts the body surface has a circular shape. If the outer diameter of the contact surface 12a is too small, the contact area with the body surface becomes small, so that it becomes impossible to stably detect the cardiac potential. Conversely, if it is too large, it will not be possible to accurately detect a cardiac potential induced locally on the body surface. This is because a large area electrode short-circuits the cardiac potential induced on the body surface to the same potential. From the above, the outer diameter of the contact electrode 12A is 4 to 20 mm, preferably 7 to 15 mm, more preferably 8 to 13 mm, and 2 to 15 times, preferably 3 to 8 times the diameter of the rod portion 12B. I do. The center of the circular contact electrode 12A is positioned at the measurement point, and the measurement potential and the peripheral electrocardiogram around the measurement point can be stably detected. However, the contact electrode does not necessarily have to be circular, but may be elliptical, oval, or polygonal. The contact electrode having a polygonal shape can soften the feel when it comes into contact with the body surface by taking the corner of the corner portion and bending it.
[0036]
Furthermore, the contact electrode 12A has a contact surface 12a with the body surface as a curved surface that is curved to be convex at the center. As described above, the contact electrode 12A in which the contact surface 12a is curved to be convex at the center has a feature that the contact electrode 12A can always contact the body surface with a large area even when the angle with respect to the body surface changes. However, even if the radius of curvature of the contact surface 12a is too small, the area in contact with the body surface is small. In the contact electrode 12A of FIG. 8, the radius of curvature is increased at the center of the contact surface 12a, and the radius of curvature is reduced toward the periphery. The contact electrode 12A has a radius of curvature at the central portion of the contact surface 12a of 10 to 100 mm, preferably 12 to 50 mm, and a radius of curvature of the peripheral portion thereof is 1 to 20 mm.
[0037]
Further, the radius of curvature of the contact surface 12a of the contact electrode 12A can be changed depending on the part pressed against the body surface. For example, when the radius of curvature of the contact surface is increased, the contact area with the body surface is increased, and the cardiac potential can be detected stably. However, this shape is pressed against the body surface and becomes slippery. The upper electrode tends to be slippery when pressed against a part close to the patient's body. This is because the side of the body is almost vertical. In order to avoid this adverse effect, for example, the contact electrode attached to the electrode close to the body side can have a smaller radius of curvature of the contact surface than the contact electrode contacting the central part of the patient's chest, thereby making it less slippery. The contact electrode at the center of the chest increases the radius of curvature of the contact surface so that cardiac potential can be detected stably. In particular, since the cardiac potential has a high voltage in the central part of the chest, it is important to accurately detect the voltage in this part. Therefore, the contact electrode pressed on the central part of the chest increases the radius of curvature of the central part of the contact surface, and the contact electrode pressed on the part close to the body reduces the radius of curvature of the central part, making it less slippery. be able to.
[0038]
Further, although not shown, the contact surface may be a flat surface if it can be pressed perpendicularly or almost perpendicularly to the body surface. This contact electrode is also 15mm ² And a square (d / 2) of the center distance (d) between the adjacent contact electrodes 12A. ² Smaller than This contact electrode has, for example, a contact surface area of 15 to 300 mm. ² , Preferably 30-100 mm ² It can be. This contact electrode can be arranged, for example, in the central part of the chest to always contact the body surface with a large area. The contact electrode having a flat contact surface also preferably has a peripheral portion that is curved with a radius of curvature of 1 to 20 mm, so that the feel when contacting the body can be softened.
[0039]
The contact electrode 12A can be detachably connected to the rod portion 12B. The contact electrode 12A of FIG. 8 is provided with a connecting hole 12b for inserting the rod portion 12B so that the contact portion can be easily attached and detached. The distal end portion of the rod portion 12B is inserted into the connecting hole 12b and detachably connected. I have. The contact electrode 12A in FIG. 8 is detachably connected to the rod portion 12B via a set screw 17. The contact electrode 12A has a female screw hole 12c for screwing the set screw 17 in the radial direction. The contact electrode 12A is fixed to the rod portion 12B by loosening the set screw 17 and removing it from the rod portion 12B, and tightening the set screw 17. However, the structure for connecting the contact electrode 12A to the rod portion 12B so as to be detachable is not limited to the above structure. The contact electrode may be any other structure that can be mechanically or elastically detachably connected to the rod portion. In this way, the contact electrode 12A which can be detached is replaced with a new one when the surface is soiled, or when the metal of the contact surface 12a is oxidized and deteriorates, or when pathogens or the like adhere to the surface and become unsanitary, the contact electrode 12A becomes new. There are features that can be done. Further, the contact electrode 12A does not necessarily need to be connected to the rod portion 12B so as to be detachable, and may be fixed so as not to come off by soldering or welding.
[0040]
In FIG. 8, the electrode body 13 includes a box-shaped case 50 having an opening at the bottom, and two insulating plate members 51. The rod portion 12B of the conductive rod 12 is inserted through the two plate members 51 so as to be able to freely enter and exit. The two plate members 51 are arranged in parallel with each other, open through holes 51A at opposing positions, and penetrate the rod portion 12B of the conductive rod 12 into these through holes 51A. The two plate members 51 are fixed to a plurality of columns 52 disposed therebetween and are held at predetermined intervals. The rod portion 12B is an intermediate portion between the two plate members 51 and fixes the fixing ring 55. The fixing ring 55 has an outer shape larger than the insertion hole 51A, and abuts on the periphery of the insertion hole 51A to prevent the conductive rod 12 from falling out of the electrode body 13 and to specify the amount of protrusion of the conductive rod 12 at the same time. are doing.
[0041]
Further, a guide plate 53 is provided on the two plate members 51 in order to reduce the sliding resistance of the rod portion 12B that enters and exits the electrode body 13. The electrode body 13 shown in FIG. 8 has a guide plate 53 laminated and fixed on the lower surface of the plate member 51 located below and the upper surface of the plate member 51 located above. The guide plate 53 has a guide hole 53A through which the conductive rod 12 is penetrated, and the conductive rod 12 is inserted into the guide hole 53A. The guide hole 53A of the guide plate 53 is opened at a position facing the insertion hole 51A opened in the plate member 51. The guide hole 53A is located at the center of the insertion hole 51A and is smaller than the insertion hole 51A, so that the rod portion 12B can reciprocate without contacting the inner surface of the insertion hole 51A. The guide plate 53 can be made of a material that reduces the sliding resistance of the rod portion 12B that slides in the guide hole 53A, for example, Teflon (registered trademark) resin. In this manner, the structure in which the conductive rod 12 slides along the guide hole 53A of the guide plate 53 having a small sliding resistance can reduce the sliding resistance of the conductive rod 12 that enters and exits the electrode body 13 and makes the conductive rod smooth. Can reciprocate.
[0042]
Further, the electrode body 13 of FIG. 8 has a weight 56 fixed to the lower plate member 51 in order to stably arrange the electrode unit 11 on the chest surface. The weight 56 is a metal plate, such as a lead plate or an iron plate. The weight 56, which is a metal plate, can be easily adjusted by changing the number of layers. As described above, the structure in which the weight 56 is fixed to the lower portion of the electrode main body 13 can lower the position of the center of gravity of the electrode main body 13, so that the posture of the electrode unit 11 can be stabilized while the electrode unit 11 is placed on the chest surface. There is a feature that can be held. Further, the electrode body 13 having the weight 56 has a feature that the conductive rod 12 can be stably pressed against the body surface.
[0043]
The elastic pressing member 14 is a coil spring inserted through the rod portion 12B, and is disposed between the two plate members 51. The coil spring is a pressing spring, and has a lower end connected to the middle of the conductive rod 12 and an upper end connected to a conductive layer 54 such as a copper film printed on the upper plate 51. This coil spring elastically pushes the conductive rod 12 out of the electrode body 13 to press the contact electrode 12A against the body surface. However, the elastic pressing member, which is a coil spring, may be a tension spring. Although not shown, the elastic pressing member, which is a tension spring, may be inserted into the conductive rod above the upper plate and connected to the upper end of the conductive rod. The elastic pressing member has an upper end connected to a tip of a conductive rod projecting from the upper surface of the plate, and a lower end connected to a conductive layer such as a copper film printed on the plate.
[0044]
The elastic pressing member 14, which is a coil spring, is used together with a lead wire for electrically connecting the conductive rod 12 to the conductive layer 54. The elastic pressing member 14, which is a coil spring, is made of a spring steel material, a piano wire, a stainless wire, a brass wire, a nickel silver wire, a phosphor bronze wire, a beryllium copper wire, or the like. In particular, a coil spring made of a wire material containing a large amount of copper has excellent conductivity, and is suitable for a coil spring used in combination with a lead wire. Further, the conductive rod 12 shown in FIG. 8 is connected to the conductive layer 54 of the plate member 51 by a lead wire 57 in addition to the coil spring. However, the conductive rod can be connected to the conductive layer via one of the coil spring and the lead wire.
[0045]
In the conductive rod 12 shown in FIG. 8, the lower end of the elastic pressing member 14, which is a coil spring, and the lower end of the lead wire 57 are connected by soldering to a fixing ring 55 fixed in the middle of the rod portion 12B. However, the lower ends of the coil spring and the lead wire 57 can be connected to the conductive rod 12 via a connecting cylinder 58 as shown in FIG. The connecting cylinder 58 has a through hole 58A at the center thereof through which the conductive rod 12 can be inserted, and the coil spring and the lower ends of the lead wires 57 are fixed to the upper surface by soldering or the like. The connecting cylinder 58 is connected to the conductive rod 12 by screwing a set screw 59 in a state where the rod portion 12B is inserted into the through hole 58A. As described above, the structure in which the coil spring or the lead wire 57, which is the elastic pressing member 14, is connected to the conductive rod 12 via the connecting cylinder 58 is such that the conductive rod 12 is detachably connected and the conductive rod 12 can be replaced. There is.
[0046]
FIG. 10 shows a bottom view of the upper plate member 51. The plate material 51 shown in this figure has a conductive layer 54 such as a copper film printed thereon. The conductive layer 54 connects the lead 60. The lead wires 60 connected to the conductive rods 12 are assembled into one lead wire 61 as shown in FIG. 8, and are connected to the arithmetic circuit 2 by the lead wires 61.
[0047]
The upper electrode 1A composed of the plurality of electrode units 11 is suspended by the suspension mechanism 4 and placed at a predetermined position on the patient's chest, as shown in FIGS. The suspension mechanism 4 shown in these figures includes an upper and lower platform 4A that suspends the plurality of electrode units 11 in a horizontal posture, and a support platform 4B that moves the upper and lower platforms 4A up and down and left and right in a horizontal posture. The plurality of electrode units 11 are suspended from the upper and lower tables 4A via suspension strings 18. The upper electrode 1A moves the upper and lower base 4A in a horizontal posture, and arranges the rod electrode 10 including the plurality of electrode units 11 at a predetermined position. The upper electrode 1A disposed on the patient's chest is held at a predetermined position by its own weight.
[0048]
Further, as shown by the chain line in FIGS. 4 and 5, the upper electrode 1 </ b> A can securely mount the rod electrode 10 including the plurality of electrode units 11 to the patient via the mounting band 40. In the rod electrode 10 shown in FIG. 5, an elastic band 40 is connected to the outermost electrode unit 11 in each row. The mounting band 40 is provided with a connecting tool 41 at the distal end, and the leading end can be connected to the bed 3 or the fixed case 31 of the body-side electrode 1B via the connecting tool 41. As the connecting tool 41, for example, a hooking tool such as a hook can be used. The upper electrode 1A is attached to the patient by connecting the connecting tool 41 at the tip of the mounting band 40 to the side edge of the bed 3 or the fixed case 31 of the body-side electrode 1B, as shown by the chain line in the figure. The mounting band 40 shown in FIG. 5 has hooks as connecting tools 41 at the left and right ends in the figure. However, the end of the mounting band may be connected in a tubular shape, a connecting rod may be inserted into the tubular portion, and the connecting rod may be hooked on a hook or the like provided on a bed or the like to be connected. Furthermore, a hook-and-loop fastener, a hook, or the like can be used as the connecting tool without necessarily using a hook or a rod. This wearing band is composed of a first wearing band having one end fixed to a bed or a fixed case of a body-side electrode, and a second wearing band connected to an outermost electrode unit of each row of upper electrodes. A structure in which the wearing bands are connected by hook-and-loop fasteners, hooks, or the like can also be used. Since the length of the mounting bands can be adjusted by changing their connection positions, there is a feature that the upper electrode can be mounted with an optimum pressing force. Further, the length of the mounting band, which is mounted with a connecting tool such as a hook, can be adjusted by dividing the band in the middle and connecting the divided portions with a connecting member such as a hook-and-loop fastener or a hook.
[0049]
The above-described rod electrode 10 includes a plurality of electrode units 11, but the rod electrode may have a structure in which a plurality of conductive rods protrude from a single electrode body. This rod electrode can be shaped such that the lower surface of the electrode body is along the patient's chest. Further, the conductive rods disposed on the left and right sides may be disposed in a posture slightly inclined with respect to the horizontal plane.
[0050]
The cushion electrode 20 is shown in FIGS. 11 is a perspective view of the lower electrode 1B, FIG. 12 is an enlarged cross-sectional view of the lower electrode 1B, and FIG. 13 is a cross-sectional view of the body-side electrode 1C. As shown in these figures, the cushion electrode 20 has a surface layer 21 whose surface or the whole is made of an insulating material, a plurality of local electrodes 22 arranged on the surface layer 21 at predetermined intervals, An elastic pressing member 23 disposed on the back surface and elastically pressing each of the local electrodes 22 against the body surface is provided.
[0051]
As for the lower electrode 1B shown in FIG. 11, 48 local electrodes 22 are arranged in total, eight in six rows. Further, the body-side electrodes 1C shown in FIG. 3 and FIG. 13 have a total of 12 local electrodes 22 arranged in six rows in two rows. These local electrodes 22 are arranged at equal center intervals (d). The center interval (d) of the local electrodes 22 can be made equal to the center interval (d) of the conductive rods 12 of the upper electrode 1A, which is the rod electrode 10, for example. However, the center distance (d) between the local electrodes 22 of the lower electrode 1B and the body-side electrode 1C can be variously changed.
[0052]
In the cushion electrode 20 shown in FIGS. 11 to 13, the surface layer 21 is a flexible sheet 21A, and a plurality of local electrodes 22 are fixed to the flexible sheet 21A. The flexible sheet 21A is a synthetic leather that can be freely deformed. Synthetic leather has a feature that the surface is coated with a plastic layer so that sweat does not permeate and that dirt such as sweat attached to the surface can be easily wiped off. However, a plastic sheet that is not synthetic leather can also be used for the flexible sheet 21A. Also, a fabric or a nonwoven fabric can be used. Furthermore, the flexible sheet 21A can be a sheet in which a plastic sheet, a fabric, a nonwoven fabric, or the like is laminated. As the flexible sheet 21A, any flexible sheet that can be deformed along irregularities on the patient's body surface can be used. Further, as the flexible sheet 21A, a stretchable sheet is preferably used. An elastic sheet has a feature that it can be deformed along an uneven body surface. However, the flexible sheet 21A is arranged on the surface of the elastic pressing member 23 with some play, and can be deformed along irregularities on the body surface. The flexible sheet 21A covers the surface of the elastic pressing member 23 and its periphery. Further, the flexible sheet 21A also covers the back surface of the elastic pressing member 23 and can be connected on the back surface.
[0053]
The local electrode 22 is made of metal and is elastically pressed against the body surface to detect a cardiac potential induced on the body surface. The local electrode 22 is manufactured by pressing a metal plate. The local electrode 22 is provided with a metal plating layer on the surface of a metal plate. As the metal plating layer, gold plating, platinum plating, silver plating, silver chloride plating, nickel plating, chrome plating, sinchu plating, lead plating, or the like can be used. However, the local electrode 22 may be formed of a metal plate of stainless steel, Shinchu, lead, silver, silver chloride, or the like to have a structure without a metal plating layer on the surface. In particular, the local electrode 22 formed of a metal such as stainless steel, Shinchu or lead has a feature that it is hard to rust.
[0054]
The local electrode 22 shown in the enlarged cross-sectional view of FIG. 14 is provided on a contact electrode 22A formed by pressing a metal plate so that a contact surface 24 with the body surface is convex to the center and a back surface of the flexible sheet 21A. And the fixed portion 22B. The contact electrode 22A and the fixing portion 22B are connected so as to sandwich the flexible sheet 21A, and fix the local electrode 22 to the flexible sheet 21A.
[0055]
The contact electrode 22A has a circular contact surface 24 that contacts the body surface. The outer diameter of the contact electrode 22A is 4 to 20 mm, preferably 7 to 15 mm, and more preferably 8 to 13 mm. The center of the circular contact electrode 22A is positioned at the measurement point, and the measurement potential and the cardiac potential around the measurement point can be stably detected. Further, as shown in FIG. 14, the contact electrode 22A preferably curves the contact surface 24 to have a convex center. As described above, the contact electrode 22A in which the contact surface 24 is curved to be convex at the center has a feature that it can always contact the body surface with a large area even when the angle with respect to the body surface changes. However, even if the radius of curvature of the contact surface 24 is too small, the area in contact with the body surface is small. In the contact electrode 22A of FIG. 14, the radius of curvature is increased at the center of the contact surface 24, and the radius of curvature is reduced toward the periphery. The contact electrode 22A has a radius of curvature at the center of the contact surface 24 of 10 to 100 mm, preferably 12 to 50 mm, and a radius of curvature of a peripheral portion thereof is 1 to 20 mm.
[0056]
The contact electrode 22A has a connection protrusion 25 that penetrates the flexible sheet 21A. The connection protrusion 25 penetrates the flexible sheet 21A and is connected to the fixing portion 22B on the inner surface of the flexible sheet 21A. In the contact electrode 22A of FIG. 14, the connection protrusion 25 is made of another metal plate. The connecting projection 25 has a shape in which a flange 25B is provided at one end of a cylindrical portion 25A. The contact electrode 22A clamps the peripheral portion of the flange 25B with the peripheral portion crimped inward. The connection convex portion 25 is fixed to the contact electrode 22A by sandwiching the peripheral portion of the flange 25B on the crimped peripheral portion of the contact electrode 22A.
[0057]
The fixing portion 22 </ b> B is provided around a through hole 26 that penetrates the connecting projection 25. The connecting projection 25 inserted into the through-hole 26 is deformed so as to expand the lower end of the cylindrical portion 25A as shown by an arrow in FIG. 14 and is connected to the fixing portion 22B so as not to come off. The fixing portion 22B in FIG. 14 has an outer shape substantially equal to the outer shape of the contact electrode 22A. The fixing portion 22B can fix the local electrode 22 to the flexible sheet 21A so as not to come off. The fixing portion 22B having this shape is manufactured by press-molding a metal plate or by molding plastic.
[0058]
A lead wire 27 is connected to the local electrode 22. The lead wire 27 is connected to the local electrode 22 by soldering or spot welding. Lead wire 27 is connected to either contact electrode 22A or fixed portion 22B. Lead wires 27 connected to the respective local electrodes 22 are wired inside the elastic pressing member 23 as shown in FIGS. The lead wire 27 wired inside the elastic pressing member 23 is preferably wired in a somewhat loosened state so that even if the elastic pressing member 23 is deformed, the lead wire 27 is not broken by an excessive force. As described above, the cushion electrode 20 for wiring the lead wire 27 inside the elastic pressing member 23 has a feature that the surface can have a clean appearance and the lead wire 27 can be stably measured without disturbing the measurement. is there. Further, the connection portion between the local electrode 22 and the lead wire 27 is embedded in an adhesive 28 as shown in FIG. This structure can effectively prevent disconnection of the connection portion of the lead wire 27. The local electrode 22 is displaced each time the elastic pressing member 23 is deformed. At this time, if the connection portion of the lead wire 27 is deformed, the lead wire is easily broken. As shown in FIG. 14, in the structure in which the connection portion is embedded in the adhesive 28, the connection portion is not deformed even when the local electrode 22 moves, and disconnection of this portion can be effectively prevented.
[0059]
The elastic pressing member 23 is a plastic foam that elastically deforms. As the plastic foam, a flexible urethane foam which is foam-formed so as to have open cells is suitable. However, as the plastic foam, a soft polyvinyl chloride foam, a polyethylene foam, an ethylene vinyl acetate foam, or the like can be used. As shown in FIGS. 12 and 13, the elastic pressing member 23 may have a structure in which a plurality of elastically deforming plates 23A having different elastic coefficients are stacked. The elastic pressing member 23 is formed by laminating a flexible elastically deformable plate 23A on the electrode side on which the local electrode 22 is fixed, and is less likely to deform on the opposite side away from the local electrode 22 than the electrode side elastically deformable plate 23A. The elastic deformation plate 23A is laminated. In this structure, the local electrode 22 can be firmly pressed by the elastically deformable plate 23A, which is hardly deformed, while the local electrode 22 is pressed against the body surface by the flexible elastically deformable plate 23A on the electrode side.
[0060]
The elastic pressing member 23 has a plate shape having a thickness of 110 to 130 mm. However, the thickness of the elastic pressing member 23 can be set to 30 to 200 mm. In addition, the elastic pressing member 23 may have a shape in which the upper surface is curved along the body surface of the patient. For example, a human back is slightly curved along the spine. Therefore, the elastic pressing member provided on the lower electrode has an upper surface curved in a shape along the back, and can ideally press all the local electrodes against the body surface. Further, although not shown, the cushion electrode can be divided into a plurality of regions, and the thickness and shape of the elastic pressing member provided in each region can be changed to conform to the body surface of the patient. For example, the lower electrode may be divided into two regions, a shoulder side and a waist side, and the elastic pressing member provided on the shoulder side may be thinned and the elastic pressing member provided on the waist side may be thickened. it can. Further, although not shown, the elastic pressing member may be provided with a protruding portion at a portion facing the local electrode, and the protruding portion may press the local electrode against the body surface. Furthermore, the elastic pressing member makes it more difficult for the pressing portion facing the local electrode to deform than the other portions, and the pressing portion can firmly press the local electrode against the body surface.
[0061]
The body-side electrode 1 </ b> C of the cushion electrode 20 shown in FIG. 13 is connected to the fixed case 31 via the pushing spring 30. A gap of several mm is provided between the peripheral wall 32 of the fixed case 31 and the body-side electrode 1C so that the body-side electrode 1C can smoothly enter and exit the fixed case 31. The body-side electrode 1 </ b> C has a support plate 33 fixed to a surface pressed by the pushing spring 30. The support plate 33 is a plate made of metal or hard plastic, and is pressed by the extrusion spring 30 to push out the body-side electrode 1C toward the body surface. With this structure, the local electrode 22 can be pressed against the body surface by the elastic pressing member 23 while firmly pressing the body-side electrode 1C with the support plate 33 pushed out by the pushing spring 30. The cushion electrode 20 shown in FIG. 13 is an elastic pressing member 23 in which a plurality of elastic deformation plates 23A having different elastic coefficients are stacked. However, the cushion electrode may be constituted by a support plate and a single-layer elastically deformable plate. The cushion electrode is formed by laminating a flexible elastically deformable plate on the surface of a support plate made of metal or plastic, for example, and the local electrode is pressed against the body surface by the elastically deformable plate.
[0062]
The fixed case 31 is connected to the elevating mechanism 34 and is arranged so that the vertical position can be changed. The lifting mechanism 34 includes a support arm 34A fixed to the bottom surface of the fixed case 31 and protruding to the rear side of the body-side electrode 1C, a guide rod 34B disposed in a vertical posture and penetrating the support arm 34A, And a fixing screw 34C screwed into the arm 34A to fix the support arm 34A to the guide rod 34B. The lifting mechanism 34 adjusts the vertical position of the support arm 34A indicated by the arrow A in FIG. 13 with the fixing screw 34C loosened, and fixes the support arm 34A by screwing the fixing screw 34C to optimize the body-side electrode 1C. Fixed at an appropriate height. Further, the lifting mechanism 34 is connected to a slide mechanism 35 so that the position in the left-right direction indicated by the arrow B in FIG. 13 can be adjusted. The slide mechanism 35 includes a slide base 35A to which a lower end of a guide rod 34B is fixed, a guide rail 35B that slides the slide base 35A in a direction indicated by an arrow B, and a slide base 35A which is screwed into the slide base 35A. A fixing screw 35C for fixing to the guide rail 35B. The slide mechanism 35 adjusts the distance between the body-side electrode 1C and the patient's body side by sliding the slide table 35A in the direction shown by the arrow B with the fixing screw 35C loosened, and screws in the fixing screw 35C to slide the slide table 35A. To fix the left and right positions of the body-side electrode 1C. Therefore, the vertical position of the body-side electrode 1C is adjusted by the elevating mechanism 34, and the horizontal position of the body electrode 1C is adjusted by the slide mechanism 35, so that the body-side electrode 1C is arranged at an optimal position on the patient's body side.
[0063]
Further, the body-side electrode 1C shown in FIGS. 3 and 13 is chamfered by cutting four sides, which are peripheral portions of a surface facing the body surface on which the local electrode 22 is arranged. The body-side electrode 1C having this structure can be brought into contact with the body surface by disposing the local electrode 22 so as to protrude toward the body surface side. Therefore, it is possible to effectively prevent the peripheral edge of the pressing surface from contacting the upper electrode 1A and the lower electrode 1B, and the local electrode 22 can reliably press the body side.
[0064]
Further, the lower electrode 1B shown in FIG. 11 displays a positioning line 36 so that the patient can be laid at the correct position of the cushion electrode 20. In the cushion electrode 20 shown in this figure, four positioning lines 36 are displayed in parallel with each other at symmetrical positions. These positioning lines 36 indicate the positions of the shoulders, nipples, ribs, etc. when the patient is at the correct measurement position, and the patient can be laid down at an accurate position based on the positioning lines 36. Like that. For example, the lower electrode 1B of FIG. 11 determines the vertical position of the patient so that the nipple of the patient is located between the two central positioning lines 36, and arranges the lower electrode 1B at a predetermined position. I can do it. As described above, the cushion electrode 20 including the positioning line 36 can always lie the patient at an accurate position. Further, although not shown, the lower electrode may display a positioning line for specifying the left and right positions. Further, instead of the positioning line, the cushion electrode can display a point or a mark that can specify the vertical and horizontal positions of the patient.
[0065]
FIG. 4 shows a state in which the electrode 1 is worn on a patient. The electrode 1 is such that a patient rests on the lower electrode 1B, the body-side electrode 1C is pressed against the patient's armpit, and the upper electrode 1A is placed on the upper body surface of the patient near the heart. It is placed on the back, side and chest. The upper electrode 1A, which is the rod electrode 10, is configured such that the elastic extruded material 14 elastically pushes out the conductive rod 12, presses the contact electrode 12A against the body surface, detects the cardiac potential with the contact electrode 12A, and detects the detected cardiac potential. Is output to the arithmetic circuit. When the patient is placed on the lower electrode 1B, which is the cushion electrode 20, the elastic pressing member 23 elastically presses each local electrode 22 against the body surface, and the local electrode 22 detects the cardiac potential with the local electrode 22. Then, the detected cardiac potential is output to the arithmetic circuit. In the body-side electrode 1C, which is the cushion electrode 20, the elastic pressing member 23 also elastically presses each of the local electrodes 22 against the body surface.
[0066]
In the body surface electrocardiograph of the present invention, as shown in FIG. 2, the operation display unit 2 calculates a cardiac voltage induced on the electrode 1 and displays a body surface potential distribution map induced on the body surface. The arithmetic display unit 2 displays an arithmetic circuit 2A for calculating a body surface potential distribution map induced on the body surface from a cardiac potential induced on the electrode 1, and a body surface potential distribution map calculated by the arithmetic circuit 2A. An external output device 2B and an operation switch 2C connected to the arithmetic circuit 2A are provided. In the figure, a monitor television 2a and a printer 2b are used as the external output device 2B.
[0067]
The arithmetic circuit 2A arithmetically processes the electric signal sent from the electrode 1 according to a predetermined method. The electrode 1 detects cardiac potentials induced at a plurality of locations on the body surface, and sends the detected signal to the arithmetic circuit 2A. The measurement of the potential is performed at predetermined time intervals, and the user inputs the time interval to be measured from the operation switch 2C to the arithmetic circuit 2A. Therefore, based on a command from the arithmetic circuit 2A, the electrode 1 measures the potential at each point and outputs the voltage value to the arithmetic circuit 2A as data. The arithmetic circuit 2A calculates an equipotential point from the measured potential of each electrode 1 at regular intervals, and calculates the position of the equipotential line from this. The obtained output signal is sent to the external output device 2B, and equipotential lines are drawn by the external output device 2B to create a potential distribution map on the body surface.
[0068]
The arithmetic circuit 2A can use any device that can calculate an equipotential point by calculating an input potential signal and determine equipotential lines. As the arithmetic circuit 2A, a computer using a general-purpose MPU or CPU, a so-called microcomputer, personal computer, workstation, or the like can be used, in addition to an IC and a computer customized to enable these processes.
[0069]
Further, the arithmetic circuit 2A has a storage medium for holding and storing the value of the cardiac potential sent from the electrode 1 at each time (not shown). As the storage medium, a storage element such as a random access memory (RAM) and a register, a fixed storage device such as a hard disk, a storage medium such as a magneto-optical disk, a CD-R, a DVD, and a flexible disk can be used. However, in order to improve the processing speed, it is preferable to use a memory element with a high access speed. The arithmetic circuit 2A calculates the equipotential points based on the data stored in the storage medium or the voltage value sent from the electrode 1, and calculates line data for drawing the equipotential lines. The calculated data is sent to the external output device 2B.
[0070]
The external output device 2B displays a body surface potential distribution map based on the data of the given equipotential lines. A plurality of monitor televisions, printers, plotters, and the like can be used for the external output device 2B. In the figure, a monitor television 2a and a printer 2b are used as the external output device 2B. The user can observe the body surface potential distribution map at any time using the monitor television 2a, while printing the potential distribution map at predetermined time intervals with the printer 2b, or printing the potential distribution map at a desired time. can do.
[0071]
The data held in the storage medium need not be at each potential on the body surface. A body surface potential distribution map at an arbitrary time can also be stored. For example, it is also possible to hold the data of the equipotential lines calculated by the arithmetic circuit 2A and call up this data to switch and display the body surface potential distribution map for each time. In particular, storing the data after the operation, not the data before the operation, can save the time required for the operation, so that the time required for display on the external output device can be shortened, and the body surface can be faster. A potential distribution map can be displayed. However, it goes without saying that both the data of the potential value and the equipotential line at each point can be stored, and the data being calculated by the arithmetic circuit 2A can be held.
[0072]
The accuracy of the display of the body surface potential distribution map can be improved by adjusting the sampling interval of the cardiac potential, the time for switching the display of the potential distribution at each time, and the like. For faster and more detailed display, a high-speed computer with high processing capability, a computer with high-speed drawing using a so-called graphic accelerator having a screen display chip, a RAM, or the like is used for the arithmetic circuit 2A. Can be improved.
[0073]
【The invention's effect】
The body surface electrocardiograph of the present invention can accurately detect cardiac potential from a large number of measurement sites and reduce the fluctuation of the 0 V line while having an extremely simple electrode structure, and can create a highly accurate potential distribution map. There are features. That is, the body surface electrocardiograph of the present invention connects a conductive rod that is elastically pushed out of the electrode body and pressed against the body surface so as to be able to enter and exit the electrode body, and a rod part of the rod part. A contact electrode connected to the distal end and detecting a cardiac potential induced on the body surface by contacting the body surface, and the contact surface of the contact electrode contacting the body surface is more than the cross section of the rod portion. It is a large outer shape and its area is 15mm ² Larger than the square of the center distance (d) between adjacent contact electrodes (d / 2) ² This is because it is smaller than that. In the conductive rod having this structure, the contact surface of the contact electrode is enlarged while the rod portion is made thinner, so that the relative movement between the contact surface and the body surface can be reduced when the body surface moves. This is because, in addition to the contact surface having a large contact area being strongly pressed on the body surface, the thin rod portion can reduce the frictional resistance. Friction resistance is calculated in principle by the product of pressure and area. However, in a state where the pressure is extremely weak, no matter how low the pressure is, the frictional resistance cannot be significantly reduced. In the present invention, the frictional resistance is reduced by reducing the sliding area of the conductive rod by making the rod portion thin. This is synergistic with increasing the area of the contact surface and reduces the relative movement between the contact surface and the body surface. The conductive rod elastically pressed against the body surface slides the rod portion with small frictional resistance, and is strongly pressed against the body surface with a wide contact surface, and moves together with the body surface. For this reason, the body surface electrocardiograph of the present invention has the feature that the fluctuation of the 0 V line of the measured potential induced to the electrodes is minimized, and the cardiac potential can be detected stably and accurately with a large number of electrodes.
[0074]
Furthermore, the body surface electrocardiograph of the present invention has a contact surface area of the conductive rod of 15 mm when pressed against the body surface. ² Larger than. When the contact electrode that specifies the area of the contact surface in this range is pressed against the body surface, a conductive liquid intervenes in an ideal state between the contact surface and the body surface, and the electrode and The contact resistance with the body surface decreases. Because the contact surface contacts the body surface in a large area and covers a part of the body surface, the conductive liquid leached here is interposed between the contact surface and the body surface without drying. This is because that. Furthermore, the contact electrode that specifies the area of the contact surface within the above range includes a plurality of sweat glands in the contact area between the electrode and the body surface, and the conductive liquid leached from each sweat gland causes the electrode and the body to pass through. Reduce the contact resistance with the surface. Contact electrodes that are in electrical contact with the body surface in a low resistance state detect the cardiac potential with great accuracy and high accuracy.
[0075]
Furthermore, in the body surface electrocardiograph of the present invention, the area of the contact surface is set to the square (d / 2) of the center distance (d) between adjacent contact electrodes. ² The contact electrode hardly disrupts the distribution of the cardiac potential induced on the body surface. It means that the maximum area is the square of the center distance (d) half (d / 2) ² This is because, since the distance is smaller than that of the contact electrode, a sufficient space is formed between the adjacent contact electrodes. Therefore, the body surface electrocardiograph of the present invention can accurately and stably detect a cardiac potential from a large number of electrodes, and can create a highly accurate potential distribution map from the detected cardiac potentials.
[0076]
Furthermore, the body surface electrocardiograph of the present invention has features that the examination cost of one patient can be made extremely low, the measurement time can be shortened, and the potential distribution map can be quickly created. That is, the body surface electrocardiograph of the present invention does not require a large number of electrodes to be adhered and fixed to the body surface, and the electrodes can be attached and the conductive rod pressed against the body surface to accurately detect the cardiac potential. Because. In particular, since the conductive rod is pressed against the body surface, there is no need to discard the electrode every time it is used as in a conventional disposable electrode, and the electrodes can be used repeatedly to detect cardiac potentials of a large number of patients. Therefore, the running cost can be significantly reduced, and the body surface potential distribution map can be quickly created. Therefore, the body surface electrocardiograph of the present invention has an extremely excellent feature that can be used very conveniently for a health check or the like and can detect a heart disease at an early stage.
[Brief description of the drawings]
FIG. 1 is a potential distribution diagram of a body surface near a heart.
FIG. 2 is a block diagram of a body surface electrocardiograph according to one embodiment of the present invention.
FIG. 3 is a schematic perspective view of a body surface electrocardiograph according to one embodiment of the present invention.
FIG. 4 is a schematic cross-sectional view showing a use state of the body surface electrocardiograph shown in FIG. 3;
FIG. 5 is a front view of a rod electrode which is an upper electrode of the body surface electrocardiograph shown in FIG. 3;
FIG. 6 is a bottom view of the rod electrode shown in FIG. 5;
FIG. 7 is a perspective view of an electrode unit of a rod electrode.
FIG. 8 is a sectional view of the electrode unit shown in FIG. 7;
FIG. 9 is an enlarged sectional view showing an example of connecting a conductive rod to a coil spring and a lead wire.
FIG. 10 is a bottom view of the plate above the electrode unit shown in FIG. 7;
11 is a perspective view of a cushion electrode which is a lower electrode of the body surface electrocardiograph shown in FIG.
FIG. 12 is an enlarged sectional view of the lower electrode shown in FIG. 11;
13 is a vertical sectional view of a cushion electrode which is a body-side electrode of the body surface electrocardiograph shown in FIG.
FIG. 14 is an enlarged sectional view of a local electrode.
[Explanation of symbols]
1 ... electrode 1A ... upper electrode 1B ... lower electrode
1C ... body side electrode
2. Calculation display section 2A Calculation circuit 2B External output device
2C… Operation switch
2a: Monitor TV 2b: Printer
3 ... bed
4: Suspension mechanism 4A: Upper and lower table 4B: Support table
10. Rod electrode
11 ... Electrode unit
12: conductive rod 12A: contact electrode 12B: rod part
12a: contact surface 12b: connecting hole
12c ... female screw hole
13 ... Electrode body
14. Elastic extruded material
15: movable member
16 ... Elastic deformation plate
17… Set screw
18 ... hanging string
20 ... Cushion electrode
21: Surface layer 21A: Flexible sheet
22 local electrode 22A contact electrode 22B fixed part
23: Elastic pressing material 23A: Elastic deformation plate
24 ... Contact surface
25 ... connecting convex part 25A ... cylindrical part 25B ... flange
26 ... Through-hole
27 Lead wire
28 ... Adhesive
30 ... Extrusion spring
31… Fixed case
32 ... peripheral wall
33 ... Support plate
34 ... elevating mechanism 34A ... support arm 34B ... guide rod
34C ... fixing screw
35: slide mechanism 35A: slide base 35B: guide rail
35C: fixing screw
36 ... Positioning line
40 ... wearing band
41 ... Connector
50… Case
51: plate material 51A: insertion hole
52 ... Prop
53: guide plate 53A: guide hole
54: conductive layer
55… Fixing ring
56 ... weight
57… Lead wire
58: Connecting cylinder 58A: Through hole
59 ... Set screw
60 ... Leader
61 Lead wire

Claims (14)

An electrode (1) for detecting a cardiac potential induced on the body surface by being elastically pressed independently at a plurality of locations on the patient's body surface, and guiding the body potential from the cardiac potential detected on the electrode (1). A body surface electrocardiograph comprising:
A plurality of conductive rods (12) whose electrodes (1) are pressed at a plurality of positions on the body surface of a patient; an electrode body (13) mounted so that the conductive rods (12) can enter and exit; A rod electrode (10) including an elastic extruded material (14) for elastically extruding the conductive rod (12) from the main body (13);
The conductive rod (12) is connected to a rod portion (12B) so as to be able to move in and out of the electrode body (13), and is connected to a distal end portion of the rod portion (12B) to come into contact with the body surface and to contact the body surface. A contact electrode (12A) for detecting an induced cardiac potential; and a contact surface (12a) of the contact electrode (12A) contacting the body surface has an outer shape larger than the cross section of the rod portion (12B). Wherein the area is larger than 15 mm ² and smaller than the square (d / 2) ² of half of the center distance (d) between adjacent contact electrodes (12A). Electrocardiograph. The cross-sectional shape of the rod portion (12B) of the conductive rod (12) and the outer shape of the contact surface (12a) of the contact electrode (12A) are circular, and the outer diameter of the contact surface (12a) is the diameter of the rod portion (12B). The body surface electrocardiograph according to claim 1, wherein the ratio is 2 to 15 times. The cross-sectional shape of the rod portion (12B) of the conductive rod (12) and the outer shape of the contact surface (12a) of the contact electrode (12A) are circular, and the outer diameter of the contact surface (12a) is the diameter of the rod portion (12B). The body surface electrocardiograph according to claim 1, which is 3 to 8 times. The body surface electrocardiograph according to claim 1, wherein the outer diameter of the rod portion (12B) of the conductive rod (12) is 1.5 to 6 mm, and the outer diameter of the contact surface (12a) is 4 to 20 mm. The body surface electrocardiograph according to claim 1, wherein the conductive rod (12) is a metal rod. The body surface electrocardiograph according to claim 1, wherein the contact electrode (12A) is any one of stainless steel, Shinchu, lead, silver, and silver chloride. The body surface electrocardiograph according to claim 1, wherein the contact electrode (12A) is provided with a metal plating layer on a surface of the contact surface (12a). The body surface electrocardiograph according to claim 7, wherein the metal plating layer on the contact surface (12a) is any one of gold, platinum, silver, silver chloride, nickel, chrome, Shinchu, and lead. The body surface electrocardiograph according to claim 1, wherein the contact surface (12a) of the contact electrode (12A) is a curved surface curved to be convex in the center. The body surface electrocardiograph according to claim 9, wherein the curved surface of the contact surface (12a) has a radius of curvature of a peripheral edge smaller than that of a central portion. The body surface electrocardiograph according to claim 9 or 10, wherein a radius of curvature of a central portion of the contact surface (12a), which is a curved surface, is 10 to 100 mm. The body surface electrocardiograph according to any one of claims 9 to 11, wherein the radius of curvature of the periphery of the contact surface (12a), which is a curved surface, is 1 to 20 mm. The body surface electrocardiograph according to claim 1, wherein the rod electrode (10) comprises a plurality of electrode units (11). The body surface electrocardiograph according to claim 13, wherein the plurality of electrode units (11) are connected by a movable member (15).

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