JP2745257B2 - Portable electrocardiograph - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention measures electrocardiogram data of a patient at all times and operates an event switch when the patient is aware of symptoms such as palpitations and chest pain, and stores electrocardiogram data before and after the subjective symptoms. (Event recording), or storing long-term heart rate data obtained from the electrocardiogram data being measured, and, if necessary, as an electrocardiogram waveform (event waveform) at the time of subjective symptoms, or The present invention relates to a portable electrocardiograph configured to reproduce and display a heart rate / trend graph.

[0002]

2. Description of the Related Art Electrocardiogram data before and after subjective symptoms are stored,
A portable electrocardiograph that reproduces and displays an event waveform at the time of diagnosis is used for qualitative diagnosis of whether a subjective symptom is derived from a heart disease.

A portable electrocardiograph which stores heart rate data for the entire time during measurement regardless of the presence or absence of subjective symptoms and reproduces and displays it as a heart rate / trend graph at the time of diagnosis provides a quantitative diagnosis of heart disease. Used for

In general, a portable electrocardiograph of this type amplifies an electrocardiogram signal obtained from a body surface electrode worn on a patient, and converts the amplified electrocardiogram signal into digital electrocardiogram data. An A / D converter, a microcomputer for processing the obtained electrocardiogram data,
A display means such as a liquid crystal for displaying an event waveform, a heart rate and a trend graph is provided.

[0005] The microcomputer temporarily stores the obtained electrocardiogram data while updating the obtained electrocardiogram data in a memory loop manner, and calculates a heart rate based on the updated and stored electrocardiogram data. Storage means for storing the heart rate data; means for storing electrocardiogram data for a certain period of time before and after the operation based on the operation of the event switch as event waveform data (seizure electrocardiogram data); It has means for reading data and converting it to display data of a trend graph, and means for reading event waveform data and converting it to display data of an event waveform.

[0006] The event waveform data is processed as follows. That is, the difference between the A / D absolute value of the electrocardiogram sampled at regular intervals by the A / D converter and the A / D absolute value at the previous sampling is updated and stored as an A / D difference value, and The A / D absolute value at the time of the current sampling is updated and stored in place of the A / D absolute value at the time of the previous sampling. When converting the data into event waveform display data, the A / D difference value must be inversely converted to the A / D absolute value. They are stored as basic data.

The heart rate data is processed as follows. That is, the heart rate is calculated for each heart beat over the entire measurement period from the start of measurement to the end of measurement, and the heart rate data is stored. The heart rate is calculated as the reciprocal of the time from the R-wave peak of the previous heartbeat to the R-wave peak of the current heartbeat. That is, it is calculated by [sampling number × sampling cycle] between both R wave vertices. Note that the R-wave vertex serving as a delimiter of one heartbeat is a portion having the sharpest rise in the QRS complex, which is a feature point of the electrocardiogram waveform.

[0008] The heart rate / trend graph is a graph in which time is plotted on the horizontal axis and heart rate is plotted on the vertical axis, showing a schematic temporal variation of the heart rate. There are a plurality of types of trends, and a predetermined time interval (trend cycle) is determined for each type of trend. The rough temporal fluctuation of the heart rate is obtained by calculating the maximum value, the minimum value, and the average value of the heart rate in each trend cycle.

When converting the heart rate data into the display data of the heart rate / trend graph, a trend cycle corresponding to a type of trend selected from a very large amount of heart rate data stored over the entire measurement period. The heart rate data is read out, and the maximum value, the minimum value, and the average value of the heart rate are calculated from the data and converted into the display data of the heart rate trend.

The types of trends include, for example, a 24-hour trend, a 60-minute trend, and a 10-minute trend. Of these, the 24-hour trend is the coarsest,
The trend is the finest for 10 minutes. The 24-hour trend heart rate data is read out at a trend cycle of, for example, 12 minutes starting from the recording start time and converted into display data.
The 60-minute trend heart rate data is read out at a 30-second trend cycle and converted to display data, and the 10-minute trend heart rate data is read out at a 5-second trend cycle and converted to display data. .

[0011]

However, in the conventional portable electrocardiograph, both the event waveform and the heart rate / trend graph take a considerably long time from the display command to the actual display on the screen. There was a problem that it took.

In the case of event waveform data, only A / D absolute values are stored for the first sampling, and only A / D difference values are stored for all subsequent samplings. In reproducing and displaying the event waveform, the A / D difference value must be inversely converted to the A / D absolute value. The basis of the inverse conversion is the A / D absolute value at the time of the first sampling.

For all the event waveform data in the time range designated as the display target, each A / D difference value at the time of each sampling is inversely converted into an A / D absolute value. Since the inverse conversion is performed based on the A / D absolute value at the time of the first sampling, the more the display designated time range is temporally away from the time of the first sampling, the more time is required for calculating the A / D absolute value by the inverse conversion. In short, the display waiting time is extended accordingly.

In the case of a heart rate / trend graph, heart rate data is stored for each heart rate, and is read out at a trend cycle (for example, 5 seconds for a 10 minute trend) according to the type of the selected trend. The maximum value, the minimum value, and the average value of the heart rate in that cycle are calculated and converted into display data of the heart rate trend. Since such processing must be repeated sequentially for each trend cycle, it takes a very long time to create all the heart rate / trend data required for display and display it as a heart rate / trend graph. It will take.

In addition, storing heart rate data for each heartbeat over the entire measurement period requires an enormous storage capacity.

The present invention has been made in view of such circumstances, and shortens the time required from the display command of the event waveform and the heart rate / trend graph to the actual reproduction display, and quickly displays the information on the screen. It is an object of the present invention to make it possible to reduce storage capacity.

[0017]

A first portable electrocardiograph according to the present invention comprises an A / D converter for converting an amplified electrocardiogram signal obtained from a patient into digital electrocardiogram data, and an obtained electrocardiogram. Means for updatingly storing the A / D absolute value of the data, and updatingly storing the A / D difference value between the A / D absolute value at the time of the current sampling and the A / D absolute value at the time of the previous sampling. Means for storing the A / D difference value over a certain period of time before and after the operation of the event switch, the R-wave peak detection time for each heartbeat, and the A / D of the R-wave peak.
Means for fixedly storing the D absolute value (event recording), and in the reproduction display mode, the individual A / D difference values belonging to the display designated time range are obtained by detecting the R-wave peak of the heartbeat to which the A / D difference belongs and the R-wave peak. A means for inversely converting the A / D absolute value into an individual A / D absolute value to create display data, and a means for displaying the display data as an event waveform. is there.

Further, the second portable electrocardiograph according to the present invention comprises an A / D converter for converting an amplified electrocardiogram signal obtained from a patient into digital electrocardiogram data, and an A / D converter for the obtained electrocardiogram data. Means for updatingly storing the D absolute value, means for updating and storing the A / D difference value between the A / D absolute value at the time of the current sampling and the A / D absolute value at the time of the previous sampling. Means for calculating a heart rate based on the time interval between the R-wave peak detection time of the previous heartbeat and the R-wave peak detection time of the current heartbeat; means for temporarily storing the heart rate data; Means for obtaining a maximum value, a minimum value, and an average value of the heart rate belonging to each cycle for each predetermined trend cycle defined in the above and fixedly storing the heart rate / trend data for each trend type; During operation A over a period of time before and after the operation
/ D difference value, R-wave peak detection time for each heartbeat, and A / D absolute value of R-wave peak are fixedly stored (event recording)
Means for reading out the heart rate / trend data corresponding to the specified trend type in the playback display mode to create display data of the heart rate / trend graph of the trend type; A / D difference value of each A / D based on the R-wave peak detection time of the heartbeat to which it belongs and the A / D absolute value of the R-wave peak
It is characterized by comprising means for inverting the display data to an absolute value to create display data, and means for displaying the display data as a heart rate / trend graph or an event waveform.

[0019]

According to the first portable electrocardiograph, when generating display data of an event waveform by inverse conversion from an A / D difference value to an A / D absolute value in the reproduction display mode, as in the conventional example, It is not necessary to perform the inverse conversion based on the A / D absolute value at the time of the first sampling, and only within the display designated time range, the R wave vertex detection time and the A / D absolute value of the R wave vertex for each heartbeat belonging to the range. Since the A / D difference value at that heartbeat may be converted into an A / D absolute value based on the
Regardless of how far the display specified time range is apart from the time of the first sampling, the A / D difference value
Event waveform display data can be quickly created by inverse conversion to / D absolute value.

According to the second portable electrocardiograph, the maximum value, the minimum value, and the average value of the heart rate belonging to each trend cycle are obtained and stored in advance during the measurement of the electrocardiogram data. In the playback display mode, it is not necessary to calculate the maximum value, minimum value and average value from the heart rate data as in the conventional example, and the display data of the heart rate / trend graph can be created very quickly. Can be.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a portable electrocardiograph according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing an electrical configuration of a main part of the portable electrocardiograph.

In the figure, reference numeral 2 denotes a body surface electrode worn on a patient, 4 denotes an ECG amplifier for amplifying an electrocardiogram signal picked up by the body surface electrode 2, and 6 denotes an amplified analog ECG signal to digital ECG data. A to convert
A / D converter, 8 is a central processing unit of the microcomputer and controls the overall control, 10 is a ROM storing programs, 12 is a RAM as a working memory and a user memory, and 14 is driven and controlled by the CPU 8. A liquid crystal driver 16; a liquid crystal display device configured to arrange fine liquid crystal display elements in a matrix vertically and horizontally so that various data can be displayed as numerical values, graphs, and waveforms; and 18, a liquid crystal display device 18 for inputting various operations. A touch key 20 is an event switch to be pressed when the patient feels subjective symptoms such as palpitations and chest pain. The touch keys 18 are formed on a transparent touch panel according to the key display of the liquid crystal display device 16.

The RAM 12 stores electrocardiogram data (A / D absolute value and A / D data) sampled by the A / D converter 6.
(D difference value) together with time information via the CPU 8 in a memory loop system. CP
U8 calculates the heart rate based on the electrocardiogram data temporarily stored in the RAM 12 by the update storage, and calculates the maximum value of the heart rate belonging to each cycle for each trend cycle determined for each trend type from the heart rate data. It has a function of calculating heart rate / trend data which is a minimum value and an average value. The RAM 12 has an area for storing heart rate / trend data obtained by calculation together with time information. The CPU 8 has a function of storing electrocardiogram data for a certain period of time before and after the operation of the event switch 20 in the RAM 12 as event waveform data in accordance with the pressing operation of the event switch 20. The RAM 12 has a capacity sufficient to store at least several minutes of electrocardiogram data and 48 hours of heart rate / trend data.

2 to 6 show a memory map of the RAM 12.

As shown in FIG. 2, the RAM 12 comprises a main body RAM 12a and a battery-backed IC card RAM 12b. The main body side RAM 12a stores the sampled electrocardiogram data (A
/ D absolute value and A / D difference value) is a buffer area for waveform measurement having an area for temporarily storing the same.

The IC card-side RAM 12b stores a time at which measurement of electrocardiogram data (A / D absolute value) is started, a time at which an event is recorded, and the like.
₁ (see Figure 3 for details), Q at rest as event 0
Area 12b ₂ for storing RS data and waveform data, area 12b ₃ for storing QRS data and waveform data during the first event recording as event A, and QRS data and waveform data during the second event recording as event B An area 12b _{4 for} storing the heart rate / trend data to be calculated within 48 hours, and an area 12b ₅ for storing the heart rate / trend data when displaying 24 hours for one screen on one screen. , the area 12b ₇ for storing 288 times the heart rate trend data when displaying area 12b _6, 10-minutes for storing 48 times the heart rate trend data when displaying 60-minutes on one screen in one screen And so on.

The areas 12b _{2 to} 12b ₄ are used as event buffer areas. The memory configuration of each event in these event buffer areas is as shown in FIG. The channels CH0 and CH1 are based on the arrangement of the body surface electrodes 2. Each waveform data is stored in the form of an A / D difference value (described later).

The memory configuration of the QRS table is as shown in FIG. 5 for one heartbeat.

That is, the detection time of the peak of each wave of the QRS complex per heartbeat (hereinafter, represented as the R-wave peak detection time) and the A / D absolute values of the channels CH0 and CH1 are stored. ing.

The memory configuration of the areas 12b _{5 to} 12b ₇ is as shown in FIG. That is, the maximum value, the minimum value, the average value of the heart rate belonging to each cycle and the total number of heartbeats detected within one cycle are stored for each predetermined trend cycle. Here, the trend period, in the case of area 12b ₅ 24 hours trend was 12 minutes, in the case of trend 60 min area 12b ₆ is 30 seconds, the trend 10 minutes Area 12b ₇
Is 5 seconds.

Next, the operation of the portable electrocardiograph of this embodiment will be described with reference to the flowcharts shown in FIGS.

When the power is turned on, the control operation by the CPU 8 is started. The electrocardiogram signal picked up by the body surface electrode 2 and amplified by the electrocardiographic amplifier 4 is A / D
Input to converter 6. The CPU 8 performs the following control operation according to the program read from the ROM 10.

When the power is turned on, the liquid crystal display device 16
The notation of the measurement key and the reproduction key is displayed as the touch key 18.

First, in step S1, it is determined whether or not the measurement key of the touch key 18 has been operated. When it is determined that the operation has been performed, the routine of steps S2 to S9 is executed. Otherwise, it is determined in step S10 whether or not the reproduction key of the touch key 18 has been operated. If it is determined that the reproduction key has been operated, step S11 is performed.
Otherwise, return to step S1.

In step S11, the process waits for either the event reproduction key or the trend reproduction key to be pressed, and when it is determined that the trend reproduction key has been operated, the routine of steps S12 to S17 (see FIG. 12) is executed. When it is determined that the event reproduction key has been operated, the routine of steps S18 to S22 (see FIG. 13)
(Details will be described later).

After the power is turned on, generally, the measurement key is first input. Therefore, proceeding to step S2, the CPU 8 controls the A / D converter 6 and
The amplified electrocardiogram signal input to the converter 6 is sampled at regular intervals, converted into digital electrocardiogram data by A / D conversion, and taken into the CPU 8. Then, in step S3, the CPU 8 transfers the continuously sampled electrocardiogram data together with the time information to the main body side RAM 12a in the RAM 12, and temporarily stores the same in a memory loop system.

FIG. 8 shows a detailed flow of the data storage operation in the memory loop system. In step S3-1,
The CPU 8 stores the electrocardiogram data (A / D absolute value, A / D difference value, which will be described later) after digital conversion by the A / D converter 6 in the waveform measurement buffer area of the main body side RAM 12a in the RAM 12. Transfer and temporarily store. In step S3-2, it is determined whether or not the event storage based on the operation of the event switch 20 has been completed.
-3, but when it is completed, step S in FIG.
Skip to 4 (search for R-wave vertex).

In step S3-3, the CPU 8 sets the RA
In the event buffer area of the IC card-side RAM 12b in the M12, the electrocardiogram data (A / D absolute value, A / D difference value) for the latest one minute from the present time is always stored starting from the present time. It is updated and stored as follows. The stored contents are constantly changing until the event switch 20 is operated.

In step S3-4, it is determined whether or not the event switch 20 has been operated. If the event switch 20 has not been operated, the process skips to step S4. Stop updating and storing the latest one-minute electrocardiogram data (A / D absolute value, A / D difference value) in the RAM 12b,
The latest one-minute electrocardiogram data (A
/ D absolute value, A / D difference value) along with time information in RAM
In the event buffer area of the RAM 12b on the IC card side in FIG. Then, after that, the electrocardiogram data for one minute (A / D absolute value, A / D
D difference value) together with the time information and fixedly stored.

As described above, when a patient feels a subjective symptom such as palpitations or chest pain and operates the event switch 20, electrocardiogram data (A / D absolute value) for a total of two minutes from one minute before to one minute thereafter. , A / D difference values) are stored in the IC card RAM 12 b of the RAM 12 together with time information as event waveform data (seizure electrocardiogram data). Then, after setting an event storage completion flag in step S3-6, the process proceeds to step S4.

The main body side RAM 12a in the RAM 12
(Buffer area for waveform measurement) and RAM on IC card side
The electrocardiogram data stored in the buffer 12b (event buffer area: ring buffer) is stored as an A / D difference value and an A / D absolute value. The detailed operation will be described with reference to the flowchart of FIG. This flow is a more detailed representation of step S3-1 in FIG.

In step S3-1-1, the CPU 8 subtracts the A / D absolute value at the previous sampling already stored as a variable in the waveform measurement buffer area from the A / D absolute value at the current sampling. , This is A / D
The difference value is transferred to the event buffer area and temporarily stored.

Then, in the next step S3-1-2, the A / D absolute value at the time of the current sampling is stored as a variable instead of the A / D absolute value at the time of the previous sampling.
The process proceeds to step S3-2 in FIG.

Here, the description of the flow is returned to FIG.

The CPU 8 determines in step S4 that the RAM 12
An electrocardiogram waveform is analyzed based on the electrocardiogram data read out from the PC to search for data corresponding to the R-wave peak serving as a delimiter of one heartbeat. The R-wave vertex is a portion having the sharpest rise in the QRS complex, which is a feature point of the electrocardiogram waveform. As a method of searching for the R wave apex, for example, the value of the electrocardiogram data at a certain point in time exceeds 70% of the maximum value of the electrocardiogram data group within one heartbeat before that, and is a local maximum point. This can be realized by determining the conditions.

If it is determined that the peak is the R-wave peak, step S5
Otherwise, the process returns to step S2 via steps S7 to S9.
7 to S9 are repeated.

When the peak of the R wave is found, the flow advances to step S5 to calculate the heart rate. The detailed operation of step S5 will be described with reference to the flowchart of FIG.

That is, in step S5-1, C
PU8 calculates the R-wave peak detection time of the previous heartbeat and the R-wave of the current heartbeat.
The reciprocal of the time interval from the wave crest detection time is calculated, and this is set as the heart rate. The time interval is obtained by [sampling number × sampling period] between the detection times of the two adjacent R-wave vertices before and after. The calculated heart rate data is
It is temporarily stored in the event buffer area in the IC card RAM 12b.

Next, in step S5-2, the R-wave peak detection time of the current heartbeat is temporarily stored in the event buffer area of the IC card RAM 12b. The R-wave peak detection time is detected as the elapsed time from the measurement start time of the electrocardiogram data. Further, step S5
-3, the A / D absolute value of each of the channels CH0 and CH1 at the time of detection of the R-wave peak of the current heartbeat is calculated on the IC card side RA.
It is stored in the event buffer area of M12b.

That is, the R-wave peak detection time for each heartbeat from the start of measurement and the A / D absolute value of the R-wave peak are stored. Therefore, naturally, the R-wave peak detection time and the A / D absolute value of the R-wave peak for each heartbeat for two minutes before and after the operation of the event switch 20 are also stored.

The CPU 8 then proceeds to step S6 shown in FIG.
The detailed operation of step S6 will be described with reference to FIG.

First, in step S6-1, the heart rate data calculated in step S5-1 and temporarily stored in the IC card RAM 12b is searched every 12 minutes, which is the trend cycle of the 24-hour trend. The maximum value, the minimum value, the average value of the heart rate and the total number of heartbeats detected during one cycle (12 minutes) are obtained from the heart rate data group belonging to one cycle for 12 minutes. Then, these data are stored in the IC card side RAM 12b as heart rate / trend data for one cycle as shown in FIG.

Similarly, in step S6-2, I
The heart rate data temporarily stored in the C card side RAM 12b is searched every 30 seconds, which is the trend cycle of the 60-minute trend, and the heart rate data of the heart rate data group belonging to one 30-second cycle is searched. The maximum value, the minimum value, the average value, and the total number of heartbeats detected during one cycle (30 seconds) are obtained. Then, these data are also stored in the IC card side RAM 12b as heart rate / trend data for one cycle. Further, in step S6-3, the heart rate data temporarily stored in the IC card
A search is performed every 5 seconds, which is the trend cycle of the 0 minute trend, and the maximum, minimum, and average values of the heart rate and one cycle (5 seconds) are selected from the heart rate data group belonging to one cycle of the five seconds. The total number of heartbeats detected during the period is calculated. Then, these data are also stored in the IC card side RAM 12b as heart rate / trend data for one cycle.

That is, the heart rate data is temporarily stored, and is determined for each trend type (24 hour trend, 60 minute trend, and 10 minute trend) during the measurement of the heart rate data (electrocardiogram data). For each predetermined trend cycle (12 minutes, 30 seconds, and 5 seconds), the maximum value, minimum value, average value, and total number of heart rates belonging to each cycle are set in advance on the IC card side as heart rate / trend data for each trend type. It is stored in the RAM 12b.

The calculation / storage of the heart rate / trend data is performed by operating the stop key of the touch key 18, by recording an event a predetermined number of times, or by performing 48 hours from the start of the measurement. Continue repeatedly until the time has passed. That is, in step S7, the touch key 18
When it is determined that the stop key has been operated, the process returns to step S1. In step S8, the event recording is performed only a predetermined number of times (two times in this embodiment), and the number of times of event recording is reduced. When it is determined that the measurement has been performed, and when it is determined in step S9 that the measurement time has passed 48 hours, the power is automatically turned off.
Then, the measurement of the electrocardiogram data is completed.

Unless the stop key is operated halfway, heart rate / trend data (maximum value, minimum value, average value, and total number of heartbeats) and events of a predetermined number of recorded events are based on data measured over a maximum of 48 hours. Waveform data (A / D difference value, R-wave peak detection time and R
The A / D absolute value of the wave vertex) is stored in the RAM 12b on the IC card side of the RAM 12.

After the stop key is operated, or
When the power is turned on again after a lapse of time, normally, the determination in step S1 is negative, and the process proceeds to step S10 shown in FIG. That is, the process proceeds to step S11 after the reproduction key is operated with the touch key 18. In step S11, it is waited whether one of the trend reproduction key and the event reproduction key is operated.

If it is determined in step S11 that the trend reproduction key has been operated, the flow advances to step S12 shown in FIG. 12 to read the heart rate / trend data (maximum value, minimum value, average value, and total number of heartbeats) from the IC card RAM 12b in the RAM 12. Is read into the CPU 8, and in step S14, the heart rate / trend data is converted into the display data of the heart rate / trend graph. This heart rate / trend graph is a graph showing the temporal fluctuation of the heart rate, with the horizontal axis representing time and the vertical axis representing heart rate.

Then, the CPU 8 transmits the display data of the heart rate / trend graph to the liquid crystal driver 14 in step S14.
Then, in step S15, the liquid crystal driver 14 is controlled to display the heart rate / trend graph on the liquid crystal display device 16. In step S16, an event mark is displayed based on the event recording time. Such display is performed in step S
The process is continued until it is determined at 17 that the stop key has been operated.

Here, in comparison with the conventional example, in the conventional example, the heart rate is not stored in the form of the maximum value, the minimum value, and the average value, but is stored in the state of the raw heart rate. The heart rate data is read out during playback and display, and for the first time, the maximum, minimum, and average values are calculated according to the trend type to create heart rate and trend data. Although it took time, in the case of the present embodiment, since the heart rate / trend data states of the maximum, minimum, and average values of the heart rate for each trend type are stored in advance, the reproduction and display are performed. At that time, the heart rate / trend data need only be read out, and it can be displayed very quickly.

In the conventional example, the heart rate data over the entire measurement period was all stored in the RAM 12b on the IC card side, so an enormous storage capacity was required. In the case of the present embodiment, however, the maximum value for each trend type was required. , The minimum value, the average value, and the total number of heart beats, the heart rate data is erased, so that the required storage capacity can be greatly reduced.

The heart rate / trend data (maximum value, minimum value, average value, and total number of heartbeats) are continuously stored over a long period of 48 hours regardless of the presence or absence of the patient's subjective symptoms. By displaying it as a heart rate / trend graph on the liquid crystal display device 16, it is used for quantitative diagnosis of heart disease.

When it is determined in step S11 in FIG. 7 that the event reproduction key has been operated, the flow advances to step S18 shown in FIG. 13, and event waveform data (seizure electrocardiogram data) is stored in the event buffer area of the IC card RAM 12b. Is read into the CPU 8 and a step S1
At 9, the event waveform data is converted into display data.

Since the event waveform data is basically stored as an A / D difference value, in order to create display data, it is necessary to perform sampling for all event waveform data within a time range designated as a display target. A /
It is necessary to inversely convert each D difference value into an A / D absolute value.

By the way, in the conventional example, only the A / D absolute value only at the time of the first sampling is stored.
Since the inverse conversion from the / D difference value to the A / D absolute value is performed based on the A / D absolute value at the time of the first sampling, the A by the inverse conversion becomes larger as the display designated time range becomes farther from the time of the first sampling. There is a disadvantage that the calculation of the absolute value of / D requires more time, and the display waiting time is extended accordingly.

On the other hand, in the case of the present embodiment, the R-wave peak detection time and the R-wave peak
Since the / D absolute value is obtained and stored in the IC card RAM 12b, when generating the display data of the event waveform, the A / D difference value of the display waveform is stored based on the R wave peak detection time. Search for the address
Next, the A / D difference value within the display designated time range may be inversely converted to the A / D absolute value based on the A / D absolute value of the R-wave peak of the heartbeat.

In other words, the A / D at the time of the first sampling
The absolute value may not be used as a reference, and the A / D absolute value of the peak of the R wave within the same heartbeat may be used as a reference. Therefore, no matter how far the display specified time range is from the measurement start point, it is extremely quick. Since the inverse conversion to the A / D absolute value, that is, the creation of the display data is performed, the waiting time until the actual reproduction display on the display screen of the liquid crystal display device 16 can be extremely short.

In the following step S20, the display data of the event waveform is transferred to the liquid crystal driver 14, and the process proceeds to step S20.
At 21, the liquid crystal driver 14 is controlled to display the event waveform on the liquid crystal display device 16. This display is displayed in step S22.
Is continued until it is determined that the stop key of the touch keys 18 has been operated. When the stop key is operated, the process returns to step S1.

As described above, since the display of the heart rate / trend graph and the display of the event waveform are performed very quickly, the doctor can quickly make a quantitative diagnosis and a qualitative diagnosis of a heart disease. .

[0071]

As described above, according to the first portable electrocardiograph according to the present invention, at the time of reverse conversion from the A / D difference value to the A / D absolute value, only in the display designated time range. Since the inverse conversion may be performed based on the R-wave peak detection time belonging to the range and the A / D absolute value of the R-wave peak, it is possible to quickly create the event waveform display data. , The time required for the reproduction display can be greatly reduced, and the diagnosis efficiency can be improved.

According to the second portable electrocardiograph according to the present invention, the maximum value, the minimum value and the average value of the heart rate belonging to each trend cycle are already determined for each trend type during the measurement of the electrocardiogram data. In the playback display mode, the display data of the heart rate / trend graph can be created simply by directly reading out the data, so that the time required from the display command to the actual playback display is extremely short. Can be something.
In addition, it is not necessary to store an enormous number of heart rate data for each heart beat, and only the heart rate and trend data for each trend type need to be stored. Can be.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electrical configuration of a main part of a portable electrocardiograph according to one embodiment of the present invention.

FIG. 2 is a memory map of a RAM in the embodiment.

FIG. 3 is a memory map of a RAM in the embodiment.

FIG. 4 is a memory map of a RAM in the embodiment.

FIG. 5 is a memory map of a RAM in the embodiment.

FIG. 6 is a memory map of a RAM in the embodiment.

FIG. 7 is a flowchart for explaining the operation of the embodiment.

FIG. 8 is a flowchart for explaining the operation of the embodiment.

FIG. 9 is a flowchart for explaining the operation of the embodiment.

FIG. 10 is a flowchart for explaining the operation of the embodiment.

FIG. 11 is a flowchart for explaining the operation of the embodiment.

FIG. 12 is a flowchart illustrating the operation of the embodiment.

FIG. 13 is a flowchart for explaining the operation of the embodiment.

[Explanation of symbols]

 2 Body surface electrode 4 Electrocardiographic amplifier 6 A / D converter 8 CPU 10 ROM 12 RAM 12a Body side RAM 12b IC card side RAM 14 Liquid crystal driver 16 Liquid crystal display device 18 Touch key 20 Event switch

Claims (2)

(57) [Claims] An A / D converter for converting an amplified electrocardiogram signal obtained from a patient into digital electrocardiogram data, means for updatingly storing an A / D absolute value of the obtained electrocardiogram data, Means for updatingly storing an A / D difference value between the A / D absolute value at the time of sampling this time and the A / D absolute value at the time of previous sampling; Means for fixedly storing (event recording) the A / D difference value, the R-wave peak detection time for each heartbeat, and the A / D absolute value of the R-wave peak, and belongs to the display designated time range in the reproduction display mode Each A / D difference value is calculated by detecting the R-wave vertex detection time of the heartbeat to which it belongs and the A / D of the R-wave vertex
A portable electrocardiograph comprising: means for inverting individual A / D absolute values based on absolute values to generate display data; and means for displaying the display data as an event waveform. 2. An A / D converter for converting an amplified electrocardiogram signal obtained from a patient into digital electrocardiogram data, and means for updatingly storing an A / D absolute value of the obtained electrocardiogram data; Means for updatingly storing the A / D difference value between the A / D absolute value at the time of the current sampling and the A / D absolute value at the time of the previous sampling; Means for calculating the heart rate based on the time interval from the wave crest detection time; means for temporarily storing the heart rate data; belonging to each cycle for each predetermined trend cycle defined for each type of trend Means for obtaining the maximum value, minimum value and average value of the heart rate and for fixedly storing them as heart rate / trend data for each trend type; A / D for a fixed time before and after the operation of the event switch when the event switch is operated Means for fixedly storing (event recording) the difference value, the R-wave peak detection time for each heartbeat, and the A / D absolute value of the R-wave peak, and a heartbeat corresponding to the specified trend type in the playback display mode. Means for reading the number / trend data and creating display data of a heart rate / trend graph of the trend type; A / D at top of R wave
Means for inverting individual A / D absolute values based on absolute values to create display data; and means for displaying each of the display data as a heart rate / trend graph or an event waveform. Portable electrocardiograph.