JPH0334928B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Technical Field The present invention is a cardiac surface excitation propagation diagram creation device, and more specifically, an apparatus for automatically mapping how excitatory potentials are propagated on the cardiac surface of an atrium or a ventricle. This invention relates to a cardiac surface excitation propagation diagram creation device.

(b) Prior art Cardiac surface excitation propagation diagrams are indispensable for detecting abnormal pre-excitation areas in the surgical treatment of WPW syndrome and intractable ventricular tachycardia. This is the most effective means for diagnosing indoor conduction disorders. In addition, this propagation diagram can be applied to the differentiation of surgical right bundle branch block after intracardiac repair of congenital heart disease, to the left side, and to intraventricular propagation disorders that cannot be diagnosed on electrocardiograms. This will provide valuable basic data for improving diagnosis in connection with potential distribution display.

However, creating this propagation diagram is based on an open examination method that requires direct application of electrodes to the cardiac surface, and in clinical practice, time constraints are imposed during surgery. Conventionally, measurement of excitation transmission time, creation of propagation diagrams, etc. were all done manually, which required a considerable amount of time for a single test, and furthermore, due to the troublesomeness of manual procedures, it was difficult to use it even though it was an effective method. Limited scope.

In addition, detection of the atrial retrograde conduction site of Kent's bundle in WPW syndrome, detection of abnormal excitation site in atrial tachycardia due to ectopic excitation, and surgical surgery for supraventricular arrhythmia or cardiac surgery for congenital heart disease. Attempts have been made to create an excitation propagation diagram for the cardiac surface of the atrium, such as elucidation of arrhythmia after atrial incision, and this is as important as the ventricular propagation diagram; Currently, there is no effective means to create a surface excitation propagation diagram.

(c) Purpose Therefore, the present invention has been made in view of the above conventional points, and it is possible to objectively and quickly create the state of excitation transmission without relying on the limbs, and to detect the excitation propagation on the cardiac surface of the atrium. It is an object of the present invention to provide a cardiac surface excitation propagation diagram creation device that can be applied to create diagrams.

(d) Structure of the Invention According to the present invention, in order to achieve this object, there is provided a measurement sensor for measuring myocardial excitation potential, and a biopotential measurement method for processing the myocardial excitation potential measured by this sensor to identify the arrival of excitation. an excitation and transmission time measurement circuit that measures the time difference between a reference pulse related to the myocardium and a pulse obtained from a biopotential measurement circuit in response to this reference pulse; We adopted a configuration consisting of a means for calculating lines and creating a cardiac surface excitation propagation diagram.

(e) Examples The present invention will be explained below based on examples shown in the drawings.

First, the method for measuring excitement transfer time used in the method of the present invention will be explained. The principles of the pacing method and the reference method are illustrated in FIG. 1a and FIG. 1b, respectively. In the pacing method, the excitation transmission time is measured using the atrial pacing pulse as a reference.The atrium is paced externally, and the time (Te) from the atrial pacing pulse to the excitation potential waveform at each measurement point is measured. This is a method in which the excitation transmission time (T) is obtained by subtracting the reference time (Tr) to the first rising point of the electrocardiogram standard lead QRS wave.

On the other hand, in the reference method, a reference electrode is attached to an arbitrary part of the ventricle or atrium, and the relative excitation transmission time difference (T _RP , −T _RP ). Specifically, T _RR and T _RP are measured, and T _RP > T _RR
-T _RP is considered to be excited earlier than the reference pulse, and is set as (-T). On the other hand, when T _RP <T _RR −T _RP , T is used as the excitement transmission time.

A block diagram of an apparatus for specifically creating an excitation propagation diagram on the heart surface using such a measurement method is shown in FIG. 2. In the figure, the number 1 indicates a pulse generation circuit, and a predetermined pulse (pacing pulse) is generated through this pulse generation circuit.
is delivered to the patient's atrium. When this pulse generating circuit is used, it is mainly used when a pacing method is used, and pacing pulses are applied to the heart from the outside. Furthermore, when using the reference method, the reference electrode 2 is placed at a predetermined location in the atrium or ventricle. As this reference electrode, a clip electrode 2a or a patch electrode 2b is used as shown in FIGS. 3a and 3b. This reference electrode is used for electrocardiograms.
It detects the pulse emitted based on the R point of the QRS wave. This reference electrode 2 is connected to a biopotential measurement circuit 4, which identifies the reference pulse. An atrial potential can be obtained by simply inserting the clip electrode 2a into the atrial appendage, and the patch electrode 2b can detect potential from any location on the cardiac surface by sewing it onto the myocardium. Each electrode can be used as a pacing wire.

On the other hand, measurement electrodes 3 are sequentially placed in a plurality of predetermined parts of the atrium or ventricle. This measuring electrode is a rod-shaped sensor 3 as shown in FIG. 4a.
a, a ring-shaped sensor 3 as illustrated in FIG. 4b;
b, a needle-type sensor 3c as illustrated in FIG. 4c;
etc. are used. The rod-shaped sensor 3a detects the radius of the neck.
It has a 90° angle and a length of 10 mm, which is shorter than previous models, making it easier to examine the back side of the heart. The ring electrode 3b is dimensioned so that it is usually worn on the longest middle finger, and a protrusion is attached to the inside of the ring at a location that corresponds to the electrode so that the electrode position can be known by skin sensation. It has been devised so that the back side can be easily inspected. Further, the needle-shaped sensor 3c is effective for measuring the potential in a place where the myocardium is not exposed and has thick fat.

This measurement electrode 3 is connected to a similarly configured biopotential measurement circuit 5. The biopotential measuring circuit 4 and the pulse generating circuit 1 are input to the excitation transmission time measuring circuit 7 via a switch 6 which is switched depending on whether the method is a pacing method or a reference method. This measurement circuit 7 similarly receives an excitation potential pulse in response to the reference pulse from the biopotential measurement circuit 5, and measures the excitation transmission time using the method described above.

Furthermore, this device is provided with a memory scope circuit 8, which includes biopotential measurement circuits 4, 5,
It is connected to the electrocardiograph 17 and the excitement transfer time measuring circuit 7, and displays the time measured by the circuit 7, the myocardial potential waveform measured by the circuits 4 and 5, and the electrocardiogram waveform output from the electrocardiograph 17 via the CRT 10. let Further, the excitement transfer time measuring circuit is connected to a computer 11 via an interface 9.
The computer 11 calculates isochronous lines based on the excitation transmission time transferred via the interface 9, as will be described later, and creates a cardiac surface excitation propagation diagram. The propagation diagram created by this computer 11 is displayed on a color CRT 12, stored as measurement data in a mini-floppy disk 13, or output to a printer 15. Furthermore, connected to the computer 11 are a light pen 14 for operating the computer and a voice synthesis circuit diagram 16 for assisting during measurement.

The specific structure of the pulse generation circuit 1 is shown in FIG. 5, and includes a current setting variable resistor 25, a rate setting variable resistor 26, VFOSCs 27, 28, binary counters 29, 30, counter set 31,
It is composed of a D/A converter 32, a current amplifier 34, a rate switch circuit 33, decimal counters 35, 36, a current indicator 37, and a rate indicator 38.

Further, the specific structure of the biopotential measuring circuits 4 and 5 is illustrated in FIG. It consists of a circuit 24, a comparator 22 that compares the output of the differentiating circuit with a threshold voltage 23, and an absolute value amplifier 25, and the gain of the gain amplifier 20 is adjusted by a controller 21. The output of the differentiating circuit 24 is also connected to a memory scope.

Furthermore, the specific structure of the excitement transfer time measuring circuit is illustrated in FIG. This circuit consists of a counter 39 that receives a reference pulse from a 10KHz clock generator 45, and a register 40 connected to this counter that receives measurement pulses and latches the counter value.The contents of the counter 39 and register 30 are displayed respectively. The data are displayed on the devices 41 and 42, and are also input to the interface 9 and transferred to the computer.

Next, the operation of such a device will be explained.

First, for measurement, a reference pulse is formed.
This reference pulse can be generated using the reference method or when a reference voltage is attached to the atrium to create a propagation diagram of the ventricle, the reference electrodes 2a and 2b as shown in FIG. 3 are used to generate the reference pulse in the biopotential measurement circuit 4. . On the other hand, in the case of the pacing method, a pulse generated by the pulse generating circuit shown in FIG. 5 is used as a reference pulse. In Fig. 5, the voltage varied by variable resistors 25 and 26 for current and rate measurement is
It is converted into a frequency by VFOSCs 27 and 28 and counted into binary counters 29 and 30. The value of the binary counter 29 is D/A converted by the D/A converter 32, and a current of the D/A value is outputted at a set rate number. In this way, a pulse rate of 30 to 200 ppm and an output current of 0 to 20 mA are set, and during measurement, the rate number is fixed and output to the myocardium and the measurement section. The pulse width given to the myocardium is 1
It is fixed at ~8ms while the rate number is set between 30 and 200ppm and the output current is set between 0 and 20mA. Also, the pulse width of the pulse output to the measuring section is
1.8ms TTL output. It is configured such that the values counted by the decimal counter are displayed on the current display 37 and the rate display 38, respectively, at predetermined timing intervals.

Next, the excitation point of the measurement site on the heart surface is recognized as follows. That is, the measurement electrodes 3 are used to sequentially place the electrodes at measurement sites as shown in FIG. 9 or 10. The myocardial excitatory potential is input to the preamplifier 17 of the biopotential measurement circuit 5 shown in FIG.
Only the necessary frequency components are amplified by the gain amplifier 20. In this case, the gain controller 21 allows the gain to be selected from 1 to 8 channels in consideration of changes in biopotential or decrease in fat equipotential. Next, the differentiation circuit 24 detects the sharp rise of the excitation potential, the comparator 22 compares it with a predetermined voltage 23, and when this voltage is exceeded, a pulse is outputted via the absolute value amplifier 25. It is assumed that an excitation potential has reached the measurement electrode placed at the measurement site when this output pulse is obtained.

Subsequently, the excitation transfer time is measured by the excitation transfer time measuring circuit 7 using the reference pulse generated as described above and the potential reaching the measurement electrode 3.
For this purpose, a reference pulse is first input to the counter 39, and the counter 39 is set using this reference pulse. On the other hand, the measurement pulse is input to the register 40, and the count time of the counter 39 is latched in the register 40 to be set as the measurement time. As mentioned above, this measurement time corresponds to Te in the pacing method, while it corresponds to T _RP in the reference method. Note that the clock frequency of the counter 39 is 10 KHz, and the resolution of measurement time is 0.1 ms. This measurement time is output to the display 42 and the interface 9, and on the other hand, when the next reference pulse is input, the time _TRR between the reference pulses is output to the display 41 and the interface 9, and the counter 3
9 is reset and one cycle of operation is completed.

As described above, the excitation potential measuring circuit recognizes the excitation reaching point, and the excitation transmission time measuring circuit measures the excitation transmission time. The measured time is then converted into 8-bit ASCII code by the interface 9 and transferred to the personal computer 11.

Next, the means for creating an excitement propagation diagram using a personal computer will be explained using the flowchart shown in FIG.

Broadly speaking, the functions of this flowchart can be divided into initial settings from steps S1 to S8;
Creation of cardiac surface excitation propagation diagrams from S9 to S12, post-processing from steps S13 to S18, display of cardiac excitation propagation time at step S19, and reproduction of cardiac surface excitation propagation diagrams registered as data files from steps S20 to S26. It can be broadly divided into five categories.

The mode selection in each step is mainly done using a light pen so that even beginners can easily do it. First, before turning on the power and creating a heart surface excitation propagation diagram, perform the initial settings described below. First, in step S1, select the mode ``Measure'' for measurement, or ``Read Data'' if you wish to reproduce the heart surface excitation propagation diagram registered in the data file.

When the "Measure" mode is selected in step S1, the date is confirmed in step S2, and then the patient name and
Enter patient ID such as age and medical record number. Next, in step S4, a heart surface excitation propagation diagram is selected, that is, either the atrium or the ventricle is selected, and in step S4a, either the pacing method or the reference method is selected. Also, in step S4b, a display method is selected. There are two ways to display this: one is to create a heart surface excitation propagation diagram (matuping), and the other is to display the measured excitation and transfer time as is on a color CRT and display the earliest excitation and transfer time of the measured excitation and transfer times in red. In the former case, the process branches downward from step S4b, and in the latter case, the process branches to the right.

Next, if the reference method is selected as the measurement method, select the reference site (i.e., atrium or ventricle) in step S5, and if the pacing method is selected, turn step S5 and proceed to the measurements in steps S6 and S6a, respectively. Move on to site selection and time mode selection. The measurement site is selected when creating the ventricular heart surface excitation propagation diagram, and the right ventricle only, the left ventricle only, or the entire ventricle is selected. Also, the time mode can be selected between the normal time mode and the WPW syndrome time mode. Further, if the atrial heart surface is selected in step S4, steps S5, S6, and S6 are bypassed. Next, in step S7, a time segment for creating an isochronous line is selected. There are two time intervals, 5ms and 10ms, and both are color-coded in the order of red, purple, yellow, green, light blue, blue, and white starting from the earliest time. When this time segment selection is completed, Tmin and Tmax are input in step S8. For Tmin, input the rising point of the standard lead QRS wave on the electrocardiogram from the electrocardiogram displayed on the memory scope, and use it as the reference time Tr. On the other hand, Tmax is
From the electrocardiogram on the memory scope as well as Tmin
Enter the end point of the QRS waveform. Tmin,
After inputting Tmax, the measurement range of the measurement data is determined. Note that these Tmin and Tmax are input when creating a ventricular heart surface excitation propagation diagram using the atrial pacing method and the atrial reference method, which have a reference point in the atrium. In this way, the initial settings are completed.

Next, the creation of the heart surface excitation propagation diagram will be explained.

To create this propagation diagram, outline diagrams of the heart as shown in FIGS. 9a and 9b are used. For the ventricular heart surface, 26 measurement points for the right ventricle, 24 points for the left ventricle, and 50 measurement points for the entire ventricle are set using a developed heart diagram with the left ventricle as the corner of the fan (see Figure 9a). . On the other hand, for the atrial heart surface, as shown in FIG. 9b, a simplified diagram in which the atrial heart surface is simplified into an elliptical shape is used, and 23 measurement points are prepared. The measurement is performed by sequentially placing measurement electrodes at the measurement points set in FIG. 9 and measuring the arrival of the excitatory potential.
Measurement point instructions are displayed on a color CRT (measurement points are displayed in red), and measurement point instructions are given by a voice synthesis circuit built into the device. Measurements are sequentially performed until the data is completed in step S9b. Measurement data is taken into account for data variations such as electrode shake, and data from three consecutive heartbeats is captured. If any one of them is outside the 3ms error range, the data is considered defective and the data is retaken. If the data of three consecutive heartbeats is within the error range of 3ms, the average value of the three heartbeat data is used as the measurement data.
If the potential cannot be detected due to fat, etc., a special switch is used to pass the measurement point as NG. In addition, in the case of this device, the isochronous line is calculated at the same time as the measurement in step S9a, and the color CRT
An instant color display is shown online.

Next, the means for calculating isochrone lines will be explained.

First, as shown in Figures 10a and b, on the outline drawings of the ventricles and atria, there are 129 ventricles and 32 atria.
Divide into triangles.

The equal time is calculated by performing the following linear interpolation approximation from the measurement times of the three measurement points forming each triangle. As shown in Figure 11, the three points that make up the triangle are i, j, k, and their coordinates are (Xi,
Yi), (Xj, Yj), (Xk, Yk), and if the magnitude relationship of Ti, Tj, and Tk at that point can be expressed by the following equation Ti>Tj>Tk...(1), then the excitation transfer time Using the slowest point i as a reference, it is checked whether boundary values of isochronous lines (10 ms, 20 ms, 30 ms, etc.) exist on the i-j line segment. As a result, if a boundary value Ta exists, the coordinates (Xa, Ya) that give the boundary value are calculated using the following equation.

From a→=mj+nim+n (m=Ta−Ti/Tj−Ti, n=Tj−Ta/Tj−Ti), Xa=1/Tj−Ti}(Ta−Tj)Xi+(Tj−Ta)Xj} ……( 2) Ya=1/Tj−Ti {(Ta−Tj)Yi+(Tj−Ta)Yj} ……(3) Coordinates on the i−j line segment of the isochrone line obtained by equations (2) and (3) is obtained. Since the magnitude relationship of the three points is expressed by equation (1), Ta calculated on the i-j line segment is i-
It is clear that it also exists on the k line segment, so
Perform proportional allocation on the i-k line segment in the same way as on the i-j line segment, calculate (Xa, Ya), perform proportional allocation in the same way as (Xa, Ya) on the i-j line segment,
Calculate (Xa, Ya) and (Xa, Ya) on the i-j line segment.
Ya) and (Xa, Ya) on the i-k line are connected to create an isochronous line. The isochrone line is displayed on the CRT in a pre-specified color (red for 10ms). Such operations are repeated until the boundary value becomes smaller than the value of Tj, that is, until an isochronous line cannot be drawn on the ij, ik line segments.

Next, using point j as a reference, similar operations are performed on the j-k and i-k line segments to calculate and display isochronous lines. At this time, the value that gives the limit for isochrone display is Tk.

Also, if the magnitude relationship of Ti, Tj, and Tk can be expressed by the following formula Ti=Tj>Tk...(4), since Ti and Tj are the same,
There is no isochronous line between lines ij and ik. That is, in this case, only the processing for the j-k and i-k line segments is performed.

If the magnitude relationship of Ti, Tj, and Tk can be expressed by the following formula Ti>Tj=Tk...(5), there is no isochronous line between j-k and i-k lines, so i-j, Only the i-k line segment is processed.

If the magnitude relationship of Ti, Tj, and Tk does not belong to any of formulas (1), (4), and (5), replace the values of Ti, Tj, and Tk, and 5) Sort into one of the formulas.
For example, in the case of Ti<Tj>Tk, if Ti>Tk, replace the value of Tj with the value of Ti, and replace the replaced value of Tj with the value of Tk, similar to equation (1). do.

As described above, the isochronous line display is performed by dividing the data obtained online into three ways according to equations (1), (4), and (5), and then displaying them on the color CRT using proportional distribution. Displays isochronous lines using colors.

Once all measurements have been completed and the isochrone line display has been completed using the method described above, the next step is to identify an error during measurement (the computer was indicating the number, but the electrode was not applied to the location corresponding to the number). ) Alternatively, a selection is made to correct the clearly incorrect isochrone display (step S10). If no correction is necessary, complete the heart surface excitation propagation diagram and move on to post-processing. If correction is necessary, input the measurement point to be corrected (step S11), erase the isochronous line related to the correction point, and treat it as the same as a defective point. There are two ways to process defective points: one is to re-measure the defective point in the same way as the above measurement, and the other is to estimate it from the measurement data around the defective point (step S11a,
S12).

Next, estimation of defective points will be explained.

To estimate the defective point, the excitation transmission time of the defective point is estimated by the following least squares method. As shown in Figure 12, the excitation transmission time for measurement points 1, 2,...n
Let T ₁ , T ₂ , ...Tn be the coordinates of that point (X ₁ ,
Y ₁ ), (X ₂ , Y ₂ ), ... (Xn, Yn), the estimated excitement transfer time Ta at point a can be expressed as in the following equation.

Ta=a ₁ +a ₂ Xa+a ₃ Ya...(6) Next, find the squared error ε between the estimated value and the actual measurement value.

_ε ⁼ _o 〓 ^m=1 {Tm−( _{a 1 + a 2}
Find a ₃ . Partially differentiating equation (7) with respect to a ₁ , a ₂ , a ₃ and setting the value to 0, ∂ε/∂a ₁ = _o 〓 ^m=1 2{Tm−(a ₁ +a ₂ Xm+a ₃ Ym ) ^} = ₀ a _{1 n} ⁺ _{a 2o} ^{〓 m} ₌ ¹ (a ₁ + a ₂ Xm + a ₃ Ym)}=0 a _1o 〓 ^{m =1 Xm} ＋ _{a 2o} 〓 ^{m =} ₁
……(9) ∂ε／∂a ₃ = _o 〓 ^m=1 −2Ym {Tm−(a ₁ +a ₂ Xm＋a ₃ Ym)}= 0 a _1o 〓 ^m=1 Ym＋a _2o 〓 ^m=1 XmYm＋a _3o 〓 ^{m =1} Y ² m＝ _o 〓 ^m=1 YmTm
...(10) Equations (8), (9), and (10) are obtained, and when this is converted into a Matrix, Substituting a ₁ , a ₂ , a ₃ obtained from equation (12) into equation (6),
Find the excitement transfer time Ta at point a.

The measurement defect points are estimated using the method described above.
Since it is unknown where and how many measurement defects will occur, the following provisions have been made.

(1) When the determinant of the inverse matrix becomes 0, the average value of the values at surrounding measurement points is used as the value to be found.

(2) In order to improve the accuracy of estimation, points that have once become defective points are not used for estimating other defective points even if they have new values due to estimation.

(3) If a large number of defective measurement points occur and the number of measurement points used for estimation is 2 or less, a message indicating that estimation is not possible will be displayed on the CRT.

The heart surface excitation propagation diagram is created as described above.

Next, post-processing of the data processed as described above will be explained.

First, in steps S13 and S13a, the cardiac surface excitation propagation diagram created as described above is recorded on a recording medium such as a floppy disk. Then step
In S14, if you want to make the earliest excitation site more clear, select the earliest mapping display to determine whether or not to redraw the heart surface excitation propagation diagram using the relative time subtracted from the earliest propagation time as the reference time (0 time). Make a choice. If the earliest mapping display is selected, it is carried out in step S14a, and if it is not selected, the process moves to step S26 and the mapping is completed based on the file data. If it is desired to print out the propagation diagram created in this way, the process moves from step S15 to S17 to do so, and one cycle of processing is completed.Subsequently, the next mapping instruction is issued in step S18.

In addition, if you want to record the data on a floppy disk or the like and recreate the propagation diagram later, select the data read mode in step S1, and then proceed to step S20.
In S21, enter data, select the mapping display method, and proceed to Step S7, Step S8,
The process moves to step S9, step S9a, and then to step S14. Furthermore, when reproducing the excitation propagation diagram, it is possible to display it by coloring instead of the isochrone display used when creating it.

If the earliest time is selected in step S4b, the transmission time is measured and displayed in steps S19 and S19a, and this continues until the data is completed in step S19b.

(f) Effects As described above, according to the present invention, there is provided a measurement sensor for measuring myocardial excitation potential, a biopotential measurement circuit for processing the myocardial excitation potential measured by the sensor to identify the arrival of excitation, and a myocardial an excitation transmission time measurement circuit that measures the time difference between a reference pulse related to the reference pulse and a pulse obtained from a biopotential measurement circuit in response to this reference pulse, and an isochrone line that is calculated based on the measured excitation transmission time. Since it uses a configuration consisting of a means for creating a cardiac surface excitation propagation diagram, it is possible to objectively and early understand the state of excitation transmission without relying on hand branches, and it is easy to understand the cardiac surface excitation propagation in the atrium. It has an excellent effect in that it can be applied to creating diagrams.

[Brief explanation of the drawing]

Figure 1a is a diagram explaining the pacing method and measurement method when a reference electrode is attached to the atrium, Figure 1b is a diagram explaining the principle of the reference method, and Figure 2 is a diagram explaining the principle of the reference method.
The figure is a block diagram showing the schematic configuration of the device of the present invention.
Figures 3a, b are schematic perspective views showing different embodiments of the reference electrode, Figures 4a, b, and c are schematic perspective views showing different embodiments of the measuring electrode, and Figure 5 is a schematic perspective view of the pulse generating circuit. Detailed block diagram: Figure 6 is a block diagram showing the detailed configuration of the biopotential measurement circuit, Figure 7 is a block diagram showing the detailed configuration of the excitation and transmission time measurement circuit, and Figure 8 is the flow of control. The explained flowchart, FIGS. 9a and 9b, are explanatory diagrams showing measurement sites used to create excitation propagation diagrams for the ventricle and atrium, respectively, and FIGS. 10a and b are propagation diagrams for the ventricle and atrium, respectively. FIG. 11 is an explanatory diagram for displaying isochronous lines, and FIG. 12 is an explanatory diagram showing estimation by the method of least squares. 1...Pulse, 2, 2a, 2b...Reference electrode,
3, 3a, 3b, 3c...measuring electrode, 4,5...
Biopotential measurement circuit, 7...Excitation transfer time measurement circuit, 8...Memory scope, 9...Interface, 11...Computer, 10, 12...
CRT, 13... Floppy disk, 14...
Light pen, 15...printer, 16...speech synthesis circuit, 17...electrocardiograph.

Claims (1)

[Scope of Claims] 1. A measurement sensor that measures myocardial excitation potential, a biopotential measurement circuit that processes the myocardial excitation potential measured by this sensor to identify the arrival of excitation, and a reference pulse related to the myocardium and this reference. An excitation transfer time measurement circuit that measures the time difference between the pulse and the pulse obtained from the biopotential measurement circuit in response to the pulse, and an isochrone line is calculated based on the measured excitation transfer time to create a cardiac surface excitation propagation diagram. 1. A cardiac surface excitation propagation diagram creation device comprising: means. 2. The cardiac surface excitation propagation diagram creation according to claim 1, wherein the reference pulse is a pulse given to the myocardium by a pulse generation circuit or a pulse obtained from a biopotential measurement circuit that measures an excitation potential generated in the myocardium. Device.