Personal electrocardiogram monitor

[Detailed Description of the Invention]

The background of an invention The present invention relates to the device for supervising the electric degree of activity of the heart in a living body, and relates to a portable electrocardiogram monitor in detail. Many portable devices for supervising the electric degree of activity of the heart exist. The self-warehouse power type life monitor stored into the pocket type cylindrical container is indicated by U.S. Pat. No. 4351164. This monitor equips the electrode probe with which the skin can be stabbed so that it may be fallen and attached to that one end into subcutaneous tissue, and the other end with the LED source which shows the existence of potential and intensity which show a living body electricity degree of activity. In U.S. Pat. No. 3792700, the portable battery power type heart monitor which changes the signal gathered with two estranged electrodes which was attached to the human body into the audible B signal which shows the beat of pulsed light or the heart is indicated. A flash lamp and an audible monitor are allocated by this monitor. It is attached to two electrodes placed under a user's side with two electric leads. The ECG telephone transmitting machine using the lower electrode of the side of the form shown in U.S. Pat. No. 3792700 is also known. Since it is transmitted to a telephone line, the voice frequency abnormal conditions of this ECG signal are carried out. The device for a language-like sound to also carry out audible reproduction of the intermediary electrocardiogram signal is shown in U.S. Pat. No. 3732868. Three electrodes arranged by the triangular pattern are attached to the device housing by three L type contact arms. Intermediary To have [ as ] which can attach many heart surveillance devices to a user's arm. An example of this device is shown in U.S. Pat. No. 4230127. This device displays calculation of a beat per minute. When the beat of the cotton intermediary heart is not detected by the interval for 6 seconds, the means for turning OFF this system automatically is included in this circuit. At the time of the medical diagnosis which requires emergency, in order that the patient may show whether it is ing with serious heart arrhythmia, such as tachycardia, thin Motion, or insufficient contraction, it is very desirable to record an electrocardiogram (ECG) immediately. Even if it palpates a pulse, it only understands whether the heart is breathing out blood. When Auditory organ is used, it understands whether the heart is beating or not, but excitement of the unusual heart and the restorative feature are not known. Only ECG can provide this information. Now, the personal pocket type ECG monitor for this object does not exist. The portable ECG monitor can also use it together with the cathode-ray tube (CRT) display of ECG. It is a CRT unit which becomes U.S. Pat. No. 3848582 from the battery power type cathode ray oscilloscope stored into the metallic housing, and is Then, The CRT unit which has the pistol grip allocated under the pickup electrode directly allocated in the backside of a housing and the housing is indicated. In the case of this device, in order to aim at a patient's skin and the right contact, it is not necessary to use electrode gel. Fields of a CRT display are 5.08 cm x the level of 7.62 cm. The depth of depth of this whole device is about 15.24 cm thru/or 20.32 cm. The expensive handling used when supervising ECG in a hospital is small as compared with a trouble device, although the CRT unit is lightweight, compared with other portable electrocardiographs, it is very bulky and it is heavy. Since this CRT consumes many electric power, consumption of a battery may also become that it is too large and electric power completely lost in the urgent situation. This spoils severely the reliability held when the medical science technician in the case of being urgent uses this device. In U.S. Pat. No. 4250503 and No. 4346378, the dot-matrix liquid crystal display (LCD) for displaying a sine wave and other continious wave forms is indicated. The waveform displayed is periodically sampled using an A/D converter, and the binary system number showing the amplitude of each sample is memorized by either an in-series shift register or random access memory (RAM). In this way, an intermediary indication of the memorized information is given also at a suitable speed to LCD. Herbert indicated in the November, 1983 item of Popular Science According to the paper written by Shyurdina "flat screen color TV", the liquid crystal which has the response time which is less than 50 milliseconds is used for the small television of the SEIKO CORP. manufacture now. The abstract of an invention In the present invention, it accomplished in order to provide an improved portable electrocardiogram monitoring device which conquered a conventional fault and a disadvantageous point of an electrocardiogram monitoring device. Therefore, handling is easy and use aims at providing a built-in-type electrocardiogram monitoring device completely [ portable / easy ]. The housing in which the portable electrocardiogram monitoring device concerning the present invention has the 1st and 2nd sides in order to achieve the above-mentioned object, It is stored by a plurality of electrodes with which the above-mentioned housing was equipped, and the above-mentioned housing, An A/D conversion machine means to change Then and the above-mentioned electrocardiogram signal into a digital signal by the circuit means which processes the electrocardiogram signal which appears when it is placed so that a patient's chest may be contacted, Then and the above-mentioned digital signal are sampled by the digital processing means combined with the above-mentioned A/D conversion machine means, and the maximum and the minimum are chosen from two or more continuing samples, A digital processing means to generate the display drive signal showing the above-mentioned maximum and the above-mentioned minimum at the speed which is a divisor of sampling speed Preparation Circuit means, It is provided in the 1st above-mentioned side of the above-mentioned housing, and is combined with the above-mentioned circuit means, and the electrooptic display which answers the above-mentioned circuit means and displays the value of the above-mentioned display drive signal is provided. Explanation of a desirable example A specific language will be used, in order to make reference about the example shown in the drawing and to explain a drawing for the object of Care(ing) an understanding of the principle of the present invention. The following things will be understood in spite of it. That is, change in an illustration device which restriction of the soul of the present invention is not meant and is explained to a drawing with a drawing, correction beyond it, and another application of the principle of the present invention are considered to usually occur for the person skilled in the art about the present invention. Drawing 1 is explained. It is shown where personal ECG monitor 10 concerning the present invention is assigned in the actuated position in contact with patient's 12 breast, and further, it is expanded and is shown in Drawing 1 so that three electrodes 14, 16, and 18 on the backside of this unit may be shown. Monitor's 10 front side contains liquid crystal display (LCD) 20. This LCD20 is constituted so that that time-axis may supply intermediary To have ECG signal sweep line 22 parallel to monitor's 10 vertical axis. A part of signal sweep line 22 is reference number 24, with it is shown. This portion shows the relative position and relative amplitude of P of the usual ECG signal, Q, R, S, and T wave. Electrodes 14, 16, and 18 are Dry electrode by which the vertical bar was also attached directly [ intermediary ] to monitor's 10 back side. If Dry electrode is used, the work which can abolish the displeasure accompanying the paste and gel which are used in order to plan electric interengagement of a patient's skin and a former type electrode, and wastes further the time of preparing a paste, gel, and the skin will become unnecessary. Although silver or silver chloride is preferred, the form of the electrode used for monitor 10 of conductive plastics or other metal is preferred, and usually shows the impedance of the level of 100 thru/or 1 K ohms in [ frequency ] 0.1 thru/or 100 Hz. These electrodes have the preferred one with possible least polarization of an electrode where it is more preferred to have stability even if it uses it repeatedly also as for a cotton intermediary to a long time. Dry electrode used for an ECG monitor is stated to Ann.Biomed.Eng. (1973, 1(3)356-357 page) by Geddes etc. The ECG signal which appears in an electrode when monitor 10 is guessed by the patient's skin is processed in digital one, before LCD20 is supplied. Drawing 2 is explained here. ECG monitor's 10 internal circuit contains zone amplifier 25 and A/D converter 26. Converter 26 is combined with microprocessor 28. In order to amplify the minute signal near the ground line of an ECG signal and to amplify a P wave especially, compression amplifier 25a may also be incorporated between amplifier 25 and A/D converter 26 if needed. As for the ratio of the maximum profit to the minimum profit, in the case of the example which uses this amplifier, 4:1 is preferred. Zone amplifier 25 connected to electrodes 14, 16, and 18 is a high gain operation amplifier which carries out a wave and it amplifies, before changing the received ECG signal into a digital type. Amplifier 25 has a common mode removal ratio of the bandwidth of 0.5 thru/or 80 Hz, about 2000 profit, at least 80 db(s), preferably 120db, and 10-megaohm input impedance. Since the input impedance of this magnitude has the quite high sauce impedance shown by Dry electrode, it is needed. It is found out that the above-mentioned filter parameter is the most effective for carrying out the wave of the noise ingredient in the signal received from Dry electrode of the above-mentioned form which is not preferred. However, other suitable zone characteristics may be used. In zone amplifier 25 or the above-mentioned alternative example, A/D converter 26 receives an ECG signal from compression amplifier 25a, is Sun ring speed of per second 800 samples, and changes this into the amplitude resolution of 8 A bit, i.e., the digital signal of 256 levels. Therefore, the digital signal output of A/D converter 26 contains the number of 8 A bit binary systems of per second 800. These binary system values are supplied to parallel input port 30 of microprocessor 28. This microprocessor 28 also includes central processing unit (CPU) 32, ROM34, RAM36, and parallel output port 38. Interconnection of all of these ingredients is carried out by data bus 40 and address bus 42. The common clock signal for synchronizing the conversion and processing of an ECG signal which are displayed is allocated in microprocessor 28 and A/D converter 26. Intermediary To have [ as ] rapidly recoverable after this circuit is equipped with the protection function to the high voltage again and a cardiac defibrillation shock is given. By the program memorized by ROM34, CPU32 processes the input digital signal received from A/D converter 26 through parallel input port 30 and data bus 40, and generates a time base signal. CPU32 impresses the address to input port 30 to address bus 42 for every one sample of the ECG signal outputted at sampling speed of per second 800 samples from A/D converter 26. In the program memorized by ROM34, About the sample succeedingly inputted from A/D converter 26, The maximum and the minimum are determined for every four continuing samples, RAM36 is made to memorize these maximums and the minimum, and the algorithm supplied to liquid crystal display 20 by making these memorized values into a display drive signal is contained. That is, CPU32 is based on the maximum, the minimum, and the display drive entry format which were these-chosen, The display drive signal value over the specific sequence of liquid crystal display 20 is calculated, and it is the speed which is a divisor of the sampling speed in A/D converter 26 about this display drive signal value, Liquid crystal display 20 is supplied as a line address signal through output line 44, and the value to which a time base signal corresponds through output line 46 is simultaneously supplied as a sequence address signal. For example, the line address signal supplied to output line 44 has 1 A bit about each A pot contained in the sequence to which the address of the liquid crystal display 20 was carried out, and controls the on/off state of corresponding A pot by the state of each A bit. Therefore, the maximum can be denoted by one A bit and this display drive signal can express the minimum by other one A bit, respectively. Then is also good by the line address signal with which a display drive signal expresses the maximum, the minimum, and the value between them by request. Thus, in one sequence address cycle, it is to liquid crystal display 20, A plurality of samples containing the maximum and the minimum of an ECG signal can be displayed, and an ECG signal can be easily displayed on the dot-matrix liquid-crystal-display speed which can be used now in real time by the above-mentioned algorithm. Although it is needless to say, sufficient speed to display the sample of all the ECG signals required to carry out exact and useful record by this algorithm is set up. Although it is very important for suitable diagnosis to get to know the amplitude and timing of for example, R wave, If it is the speed within the response capability of the usual LCD, namely, the ECG signal was sampled at the rate of one sample to 50~150 milliseconds since the amplitude of R wave changed very quickly, the peak of R wave may be overlooked. Liquid crystal display 20 answers the sequence address signal and line address signal which are supplied from microprocessor 28 by forming the sweep line showing the ECG signal acquired from an oar form electrode. Even per second 1, 2.5, 5, or speed of 10 cm generates a time base signal by intermediary real time in the form or intermediary liquid crystal display of a strip chart recorder, and microprocessor 28 performs an ECG display. It is given in order to choose display speed with a suitable preferred switch (not shown). The signal-processing algorithm for carrying out the wave of the noise in the ECG signal relevant to Dry electrode further is allocated in microprocessor 28. It has the automatic "ON" feature and microprocessor 28 usually operates by low electric power pause, i.e., "dormancy" mode, according to this feature, and monitor 10 answers detection of the contact to the skin of microprocessor 28, and operates again. This microprocessor becomes in active to signal processing and a display, only when the data from A/D converter 26 is read periodically and the data sample read is within the limits of predetermined. This feature lengthens the life of a battery. In order that the circuit which has connected the monitor circuit with the battery by the mechanical operation of pushing a monitor against a patient's breast may close the this automatic "ON" feature, the housing between electrodes -- or it may carry out with the switch which is pinched between an electrode and a housing and is attached. Another advantage is the "freezing frame" display after separating monitor 10 from a patient's skin. Data for maintaining a display in the state of existing before detaching an electrode is memorized by RAM36. Cotton intermediary LCD20 will be supplied continuously in a predetermined period, and a display will be OFF after this. All the ECG data in RAM36 can be used for transmission to next read-out and the conventional chart recorder, or other devices. It is desirable although the microprocessor of some different Noodle form is also used for the ECG monitor concerning the present invention. In order to attain miniature-ization as much as possible, the above-mentioned monitor's whole circuit is included in one hybrid circuit. Therefore, not only as for satisfying the above-mentioned use but this microprocessor, it is preferred that a hybrid circuit may be piled up. the following microprocessors and a microprocessor group -- that is, 8 A bit device is altogether preferred for these object. That is, they are other devices of other devices of other device [ of Rockwell 6502, Zilog Z80C, RCA1804, or 1800 groups ], and Motorola MC146805, or 6800 groups and Hitachi 6305, or 6300 groups. Liquid crystal display 20 is a dot-matrix liquid crystal display of the long flat screen which has a refresh rate of per second about 30 frames. LCD of some marketing has sufficient speed for the real time ECG display using the art currently indicated by this specification. As these examples, model number 4816 of model number EG-Y84320AT of Epson and SEIKO CORP. is mentioned. A device of Epson has 32 lines and 84 rows. A device of SEIKO CORP. has 64 lines and 480 rows. Therefore, only 6 A bit are required to obtain the sequence address to 64 lines, and it is understood to 32 lines that only 5 A bit are required. Therefore, only best beam 5 A bit (Epson) or 6 A bit (SEIKO) which occur by A/D converter 26 are displayed. Although it is unnecessary to the display of the sweep line to LCD described immediately before, all the 8 A bit to each ECG signal sample are held at a memory for the output to a chart recorder or other devices. According to the portable ECG monitor concerning the present invention, quicker diagnosis of the heart arrhythmia to affect the life which requires the emergency by the medical science technician, the nurse, and a surgeon is attained. While preparing so that the conventional device can be looked for, assembled and used, it will be accepted that the easy pocket type monitor which supplies rough information in several minutes of the start after a heart attack has clear clinical Substitution capability.

[Brief Description of the Drawings]

Drawings 1 are Then and a perspective view showing application on a patient's breast especially at the desirable example of the ECG monitor concerning the present invention. Drawing 2 is a block diagram of the internal circuit of the ECG monitor which shows in Drawing 1. 10 ...... A personal electrocardiogram monitor, 12 ...... A patient, 14, 16, 18 ...... An electrode, 20 ...... A liquid crystal display (LCD), 22 ...... An ECG signal sweep line, 25 ...... An amplifier, 26 ...... An A/D converter, 25a ...... A compression amplifier, 28 ...... A microprocessor, 30 [ ...... RAM, 38 / ...... A parallel output port, 40 / ...... A data bus 42 / ...... An address bus 44, 46 / ...... Output line. ] ...... A parallel input port, 32 ...... CPU, 34 ...... ROM, 36