CN219230151U - Calibration matrix generating device and wall thickness monitoring device for finding tissue thickness - Google Patents

Abstract

The utility model provides a calibration matrix generating device and a wall thickness monitoring device for searching tissue thickness. The calibration matrix generating device comprises a body environment simulation device, a calculation processing device and the like, and is used for simulating the condition that the medical catheter presses the target tissue to obtain a calibration matrix about the contact pressure value, the impedance value and the target tissue thickness. The wall thickness monitoring device comprises calculation processing equipment, a medical catheter, an impedance measuring instrument and the like, a data set closest to the contact pressure value and the impedance value is searched in a calibration matrix generated by the calibration matrix generating device, and the tissue thickness value in the data set is the heart wall thickness value monitored in real time. The utility model realizes the problem of low-cost real-time monitoring of the tissue thickness of the target ablation part in the ablation operation process, and can also determine the ablation energy and the ablation duration of the medical catheter in the ablation process based on the real-time monitored tissue thickness, thereby improving the operation safety and the ablation treatment effect.

Description

Calibration matrix generating device and wall thickness monitoring device for finding tissue thickness

Technical Field

The utility model relates to the field of medical ablation surgical instruments, in particular to a calibration matrix generation device and a wall thickness monitoring device for searching tissue thickness.

Background

Catheter radio frequency ablation is the most commonly used minimally invasive interventional technique for treating arrhythmia at present, the cause of arrhythmia is that abnormal electrical signal transmission occurs to partial tissues of the heart, and the electrical signal of the heart is abnormally conducted to other adjacent tissues, so that the normal heart cycle is interrupted to cause arrhythmia, arrhythmia occurs, and the basic principle of catheter radio frequency ablation is as follows: the method comprises the steps of sending a radio frequency medical catheter to a target heart chamber through catheters with different lengths, precisely positioning an arrhythmia origin focus under the guidance of a three-dimensional mapping technology, enabling a columnar ablation electrode at the head end of the catheter to be contacted with focus tissues by effective contact pressure, and then sending radio frequency current through a loop electrode attached to the skin of the body surface of a patient. The radio frequency current flows through the focus tissue below the electrode, heat is generated in the tissue, and when the temperature reaches the degree of coagulation necrosis, the tissue permanently loses the electrophysiological activity, so that abnormal electric signal transmission is cut off, the normal heart cycle is restored, and the arrhythmia is cured.

At present, when a doctor performs a catheter radio frequency ablation operation on a patient, the wall thickness of a heart target ablation part cannot be obtained in advance, ablation is performed on parts with thinner wall thickness on the heart, and when the operator controls the catheter to support the columnar ablation level of the head end of the catheter against the target ablation part with effective contact pressure, accidents such as heart perforation and the like caused by overlarge force are easy to occur, so that the operation safety of the patient is threatened. When ablation is carried out on a part with a thinner wall thickness of a heart of a patient, if the ablation energy controlled by an operator is too large or the ablation time is too long, the target ablation part is excessively ablated, local carbonization effect, coagulum or explosive steam burst are caused to endanger the life of the patient, the part is possibly contracted to influence the normal beating of the heart, if the ablation part is positioned near a blood vessel, the contraction of a blood vessel orifice is caused, the generation of operation complications such as blood supply insufficiency of a human body is caused, and the operation quality is influenced. When ablation is carried out on a part with thicker heart wall thickness of a patient, if the ablation energy controlled by an operator is too small or the ablation time is too short, insufficient ablation of the part is caused, and the side, far away from the head end of a medical catheter, of the heart wall is insufficiently ablated, so that the purpose of cutting off abnormal electric signal transmission is not achieved, and the operation quality is affected.

The prior art proposes a method for measuring tissue thickness using ultrasonic and force measurements by inserting a catheter having a distal section into the body of a subject and in contact with the wall of a heart chamber, said heart chamber having an inner surface and an outer surface, said distal section of the catheter having a contact pressure sensor and an ultrasonic transducer. Actuating the transducer to acquire ultrasound reflectance data from the wall of the lumen, reciprocating the catheter against the wall of the lumen and measuring a contact pressure between the catheter and the wall of the lumen upon actuation of the transducer, combining the reflectance data with the contact pressure, identifying a set of reflectance data associated with the contact pressure having a highest correlation, and determining a tissue thickness between the inner surface and the identified set of reflectance data as a function of a time of flight between the inner surface and the identified set of reflectance data.

In the technical scheme, the ultrasonic probe and other tools are used for measuring, so that the instruments are expensive, and the operation cost is too high.

Disclosure of Invention

The utility model aims to solve the problem of how to monitor the tissue thickness of a target ablation part in the ablation operation process in real time at low cost. By setting the calibration matrix generating device for searching the tissue thickness, the calibration matrix which respectively corresponds to the impedance value (tissue displacement) and the used force of different tissue wall thicknesses is obtained through testing the tissues at different thicknesses and different positions, and when the heart wall thickness is actually detected, the impedance value corresponding to the used force of the catheter on the tissue and the tissue displacement can be compared with the data in the calibration matrix, and the nearest wall thickness displayed by a group of data is the thickness of the tissue at the contact position of the catheter, so that additional ultrasonic equipment is not needed, and the operation cost is greatly reduced.

The utility model provides a calibration matrix generation device for searching tissue thickness, which is used for searching a contact pressure value, an impedance value and a corresponding target tissue thickness value of a medical catheter and target tissue. The calibration matrix generation device includes: a body environment simulation device, a simulation catheter, an impedance measuring instrument, a pressure measuring instrument, a motor control module, and a computing processing device, wherein the simulation catheter has electrodes for generating a local electric field and forming an electric signal;

the impedance measuring instrument is electrically connected with the analog catheter and converts the electric signal into an impedance value;

the motor control module is used for controlling the simulation catheter to apply pressure to experimental tissues;

the body environment simulation device is used for simulating body environment and is provided with experimental tissues;

a pressure gauge for measuring and displaying a contact pressure value of the applied pressure and transmitting the contact pressure value to the computing processing device;

the computing processing equipment is electrically connected with the impedance measuring instrument, the pressure measuring instrument and the motor control module, receives the contact pressure value and the impedance value, stores the impedance value, the contact pressure value and the thickness value of experimental tissues in a data set form, and stores data sets with different values in a matrix form to form a calibration matrix.

According to the embodiment of the utility model, the electrode comprises a first electrode and a second electrode, wherein the first electrode is arranged at the head end of the analog catheter and is used for generating a local electric field; the second electrode is adjacent to the first electrode for converting the local electric field into an electrical signal.

According to an embodiment of the present utility model, a motor control module includes: a stepping motor; the control circuit is electrically connected with the stepping motor and controls the stepping motor to move; the fixed rod is fixedly connected with the stepping motor and the simulation catheter, so that the simulation catheter is parallel to the stepping motor and moves.

According to the embodiment of the utility model, the stepping motor comprises a head part and a rod part, wherein the rod part is provided with external threads and is in threaded connection with the fixed rod.

According to an embodiment of the present utility model, a body environment simulation apparatus includes: a cylinder, a deformed porous plate and a beaker; the cylinder body is used for storing first brine, the bottom of the cylinder body is provided with a grounding plate, a deformation porous plate is arranged on the grounding plate, experimental tissues are placed on the deformation porous plate and used for deforming along with the experimental tissues, the beaker is used for storing second brine, the second brine is connected with the grounding plate through a first lead, and the second brine is connected with an impedance measuring instrument through a second lead.

According to the embodiment of the utility model, the cylinder body is placed on the pressure measuring instrument, and the pressure measuring instrument has the function of displaying the contact pressure value.

According to an embodiment of the present utility model, the calibration matrix generating device further includes a circulation pump that controls the temperature and the flow rate of the first saline to simulate human blood.

The utility model provides a heart wall thickness monitoring device, comprising: a medical catheter in direct contact with the heart wall, an impedance meter, and a computing processing device storing a calibration matrix. The medical catheter comprises an electrode arranged at the head end of the medical catheter and a pressure sensor arranged adjacent to the electrode, the electrode can generate a local electric field in real time and convert the local electric field into an electric signal, and the pressure sensor can measure the contact pressure value of the medical catheter and the heart wall in real time. The impedance measuring instrument is electrically connected with the medical catheter and converts the electric signal into an impedance value. The computing processing equipment is electrically connected with the medical catheter and the impedance measuring instrument, receives the contact pressure value and the impedance value, searches a data set closest to the contact pressure value and the impedance value in the calibration matrix, and the heart wall thickness value in the data set is the heart wall thickness value monitored in real time.

The calibration matrix generating device for searching the tissue thickness can test the contact pressure value and the impedance value of the catheter on different tissues or tissues with different thicknesses, automatically store the contact pressure value and the impedance value in the computing processing equipment, and measure the heart wall thickness by using the conventional pressure catheter by establishing the calibration matrix of different tissue materials and the impedance value corresponding to the use force of the catheter on the target tissue and the distance of the catheter synchronously displacing the tissue.

Drawings

FIG. 1 is a schematic diagram of a calibration matrix generating apparatus according to an embodiment of the present utility model;

FIG. 2 is a schematic illustration of a simulated catheter applying pressure to experimental tissue according to an embodiment of the utility model;

FIG. 3 is a schematic diagram of a device for monitoring wall thickness of a heart in real time according to an embodiment of the utility model;

fig. 4 is a schematic diagram of local electric field distortion caused by movement of a medical catheter according to an embodiment of the utility model.

Reference numerals

A medical catheter 110, a third electrode 111, a fourth electrode 112, a pressure sensor 113, an impedance meter 120, an ablation generator 130, a computing device 140, an electrode patch 150,

the calibration matrix generation means 200,

the analog catheter 210, the first electrode 211, the second electrode 212,

cylinder 220, ground plate 221, deformed porous plate 222, spacer 223, first brine 224,

the water in the beaker 230, the second brine 231,

a stepper motor 241, a head 2411, a shaft 2412, a motor control circuit 242, a fixed rod 243,

the circulation pump 250 is provided with a circulation pump,

the pressure gauge 260 is configured to measure the pressure of the fluid,

experimental organization 300.

Detailed Description

In order to further describe the technical means and effects adopted by the present utility model for achieving the intended purpose, the following detailed description of the present utility model is given with reference to the accompanying drawings and preferred embodiments.

The present utility model provides a calibration matrix generation apparatus 200 for finding a tissue thickness, the calibration matrix being used to find a target tissue thickness corresponding to a contact pressure value and an impedance value generated by a medical catheter 110 to a target tissue. The calibration matrix generation apparatus 200 includes: a body environment simulation device, a simulation catheter 210, an impedance meter 120, a motor control module, and a computing processing device 140.

The body environment simulation device includes: a cylinder 220; a first brine 224 stored in the cylinder 220; a ground plate 221 disposed at the bottom of the cylinder 220; a second brine 231 connected to the ground plate 221 through a conduit, the second brine 231 being stored in the beaker 230; the deformation porous plate 222 is placed on the ground plate 221 through the spacer 223 to place the experimental tissue 300, and the deformation porous plate 222 can be deformed synchronously with the experimental tissue 300.

Specifically, as shown in fig. 1, a first saline 224 for simulating blood is contained in a cylinder 220, a ground plate 221 is provided at the bottom of the cylinder 220, the ground plate 221 is connected to a beaker 230 for acting as a series resistor through a wire, a second saline 231 is contained in the beaker 230, and the resistivity of the second saline 231 can be controlled by the liquid level in the beaker 230 and the salinity of the saline, so that the whole circuit has an impedance similar to that of a human body. The grounding plate 221 is provided with a deformation porous plate 222 supported by a gasket 223, the deformation porous plate 222 is provided with an experimental tissue 300 to be tested, and the deformation porous plate 222 can synchronously deform along with the experimental tissue 300.

Analog catheter 210 includes electrodes that generate a local electric field and form an electrical signal; the impedance meter 120 is electrically connected to the analog catheter 210 to convert the electrical signal into an impedance value; the impedance meter 120 is connected to the beaker 230 to complete the current return path. As the analog catheter 210 contacts the experimental tissue 300 and continuously applies pressure downward to concavely deform the experimental tissue 300, the local electric field generated by the first electrode 211 of the analog catheter 210 is also changed, the fourth electrode of the analog catheter 210 senses the change of the local electric field, and the electric signal acquired by the second electrode 212 is converted into an impedance value by the impedance measuring instrument 120, wherein the impedance value is changed along with the change of the local electric field.

A motor control module that controls the simulated catheter 210 to apply pressure to the experimental tissue 300;

the computing device 140, electrically connected to the impedance meter 120 and the motor control module, receives and stores the contact pressure value, the impedance value, the type of the test tissue 300, and the thickness value of the test tissue 300, which simulate the application of pressure by the catheter 210 to the test tissue 300, to form a calibration matrix.

According to an embodiment of the present utility model, a motor control module includes: a stepping motor 241; a motor control circuit 242 electrically connected to the stepping motor 241 and controlling the movement of the stepping motor 241; the fixing rod 243 fixedly connects the stepping motor 241 and the analog guide tube 210, so that the analog guide tube 210 is parallel to the stepping motor 241 and moves simultaneously. As shown in fig. 1, the operator sends instructions to the computing and processing device 140, the computing and processing device 140 transmits the instructions to the motor control circuit 242, the motor control circuit 242 is connected with the stepping motor 241 through a cable to control the up-and-down movement of the stepping motor 241, and the stepping motor 241 is connected with the analog catheter 210 through the fixing rod 243 to control the up-and-down movement of the analog catheter 210 in the millimeter range. The distance the analog catheter 210 moves downward is recorded by the stepper motor 241 control circuitry and sent to the computing processing device 140.

The stepping motor 241 includes a head portion 2411 and a rod portion 2412, and the rod portion 2412 is screwed with an internal thread provided at one end of the fixing rod 243 by an external thread. The motor control circuit 242 controls the stepping motor 241 to work, and the rod portion 2412 of the stepping motor rotates to drive the fixing rod 243 in threaded connection with the rod portion 2412 to integrally move upwards or downwards, so that the simulation catheter 210 also moves upwards or downwards.

Each time the analog catheter 210 is moved downward, the stepper motor 241 control circuit will send the analog catheter 210 displacement Δx downward, in mm, to the computing processing device 140. The computing device 140 records and stores the contact pressure value F and the impedance value R transmitted by the impedance meter 120 into the calibration matrix. Each downward movement of the analog catheter 210 results in a corresponding set of displacements deltax and corresponding impedance values R and force values F, with all recorded information for each set of tests stored in the calibration matrix along with the known thickness of the experimental tissue 300. This operation is repeated for different types of experimental tissues 300 and different thicknesses of experimental tissues 300, and the force value and the resistance value R are collected using the above repeated operations, thereby forming a calibration matrix composed of the types of experimental tissues 300, the thicknesses of the experimental tissues 300, the displacements, the force values, and the resistance values. Typically, the calibration matrix comprises at least 3 elements of impedance values (displacement values), force values and corresponding tissue thickness values, the values of each element may be stored as interval values when stored, e.g. when stored in the calibration matrix, the values of the 3 elements may be stored in the form of { [ a1, a2], [ b1, b2], [ c1, c2] }, or in the form of { [ a1, ±Δa0], [ b1, ±Δb0], [ c1, ±Δc0] }.

As shown in fig. 2, the same force F is applied orthogonally to two test tissues 300 of different thicknesses, the test tissue 300 of thinner wall thickness having a thickness t1, resulting in a displacement Δx1, the test tissue 300 of thicker wall thickness having a thickness t2, resulting in a displacement Δx2, Δx1 > Δx2, the two different displacements resulting in different impedance values.

The resulting displacement deltax and impedance values of the medical catheter 110 against the target tissue are derived as follows. In cardiac muscle and blood, the distribution of electrical current is not simple because of the relationship of geometry and many materials (such as cardiac muscle, blood, bone, and skin). This problem can be illustrated by a metal sphere of diameter r1 surrounded by several other shells, each representing a different material. Each shell has a thickness r1 for a total of N-1 shells. Thus, the total resistance from the metal sphere to the outermost surface is given by equation 1

Wherein ρ is _n Is the resistivity of the nth ring. If ρ _n Are all equal to ρ, which means the same material, the above equation is reduced to equation 2:

since the resistivity of blood is less than the resistivity of the myocardium, the near-potential field around the tip electrode is greatly distorted when the medical catheter 110 penetrates the myocardium, with more area of the tip electrode being surrounded by the higher resistivity myocardium. Because the impedance increases rapidly as the tip electrode penetrates the target tissue. Monitoring the impedance Z of the electrode of medical catheter 110 may give a predicted displacement of the tip electrode into the target tissue. However, to predict penetration of medical catheter 110 in the target tissue, some assumptions may be considered as the process of current flowing through the ground rod, the above equation becomes equation 3:

x is the depth of penetration of the tip electrode, r _c Is the tip electrode diameter. R from medical catheter 110 gauge _c Values.

From the above equation, a calculated relationship between the displacement Δx of the medical catheter 110 against the target tissue and the impedance can be deduced, and the displacement Δx of the medical catheter 110 against the target tissue is proportional to the impedance value.

The operator can properly touch the target tissue by using the medical catheter 110, and transmit the signals sensed by the electrodes back to the impedance measuring instrument 120 to convert the signals into impedance values, and the force F applied by the medical catheter 110 to the target tissue can be directly measured by the pressure sensor 113 of the medical catheter 110. The computing device 140 can automatically match the obtained impedance value and the force F applied to the target tissue by the medical catheter 110 in the calibration matrix, so as to obtain the tissue thickness in a group of data sets closest to the impedance value and the force F applied to the target tissue by the medical catheter 110, namely the thickness of the target tissue.

The calibration matrix generating apparatus according to the embodiment of the present utility model further includes a circulation pump 250, and the circulation pump 250 controls the temperature and the flow rate of the first saline 224 to simulate the state of human blood.

The calibration matrix generating device further comprises a pressure measuring instrument 260 for measuring and displaying the contact pressure values and transmitting the contact pressure values to the computing processing device according to an embodiment of the present utility model. In fig. 1, the pressure gauge 260 records and displays the contact pressure value, with the numerical scale being in grams.

As shown in fig. 3, the device for monitoring the wall thickness of the heart in real time provided by the utility model comprises: a medical catheter 110 in direct contact with the heart wall, an impedance meter 120, and a computing processing device 140 storing a calibration matrix. The medical catheter 110 includes an electrode disposed at a head end of the medical catheter 110 and a pressure sensor 113 disposed adjacent to the electrode, wherein the electrode can generate a local electric field in real time and convert the local electric field into an electric signal, and the pressure sensor 113 can measure a contact pressure value between the medical catheter 110 and a heart wall in real time.

The impedance meter 120 is electrically connected to the medical catheter 110 and converts the electrical signal into an impedance value. The impedance meter 1208 includes a conventional filter (bandpass filter) to block the passage of signals of no interest but to allow signals of an appropriate frequency to pass, for example, the excitation frequency, and conventional signal processing software to obtain the impedance R of the signal under test.

The computing device 140 is electrically connected with the medical catheter 110 and the impedance measuring instrument 120, receives the contact pressure value and the impedance value, and searches a data set closest to the contact pressure value and the impedance value in the calibration matrix, wherein the heart wall thickness value in the data set is the heart wall thickness value monitored in real time.

According to the embodiment of the utility model, the electrodes comprise a third electrode 111 and a fourth electrode 112, wherein the third electrode 111 is arranged at the head end of the medical catheter 110 to generate a local electric field; the fourth electrode 112 is adjacent to the third electrode 111, converting the local electric field into an electric signal. As the medical catheter 110 approaches and abuts against the target tissue with a certain contact pressure, the local electric field generated by the third electrode 111 at the head end of the medical catheter 110 changes due to the different resistivities of blood and the target tissue, and as the medical catheter 110 moves, the local electric field is distorted due to the electric potential field caused by the contact between the medical catheter 110 and the high-resistivity cardiac muscle, as shown in fig. 4, when the medical catheter 110 does not contact the target tissue, the local electric field is E1, and when the medical catheter 110 contacts the target tissue, the local electric field is E2. The fourth electrode 112 senses and transmits the above-described electric field change back to the computing processing device 140, and the impedance meter 120 converts the sensed electric signal into an impedance and transmits the impedance to the computing processing device 140.

Specifically, as shown in fig. 3, in the ablation process, the electrode patch 150 is attached to the body and acts as a ground wire to complete the current reflux of the system, the signal generator generates a low-amplitude signal to excite the third electrode 111 at the head end of the medical catheter 110, thereby generating a local electric field at the catheter head end, the fourth electrode 112 is used for sensing the local electric field generated by the third electrode 111 and transmitting the sensed electric signal to the impedance measuring instrument 120 through a suitable wire, and converting the electric signal sensed by the fourth electrode 112 into an impedance value, the impedance value is transmitted to the computing and processing device 140 through the wire, the computing and processing device 140 comprises an electronic control unit, a CPU (central processing unit) and a display system, wherein the CPU compares the impedance value input from the impedance measuring instrument 120, the contact pressure value acquired from the pressure sensor 113 with a calibration matrix stored in the CPU, the tissue wall thickness in the calibration matrix closest to the acquired contact pressure value and the impedance value is the value closest to the target tissue wall thickness in contact with the medical catheter 110, and the CPU finally stores the data in an internal memory and transmits the data to the display system, and the CPU acquires the wall thickness value of the target tissue against the catheter wall thickness of the target tissue against the catheter by the display system.

According to an embodiment of the present utility model, the cardiac wall thickness real-time monitoring apparatus further includes an ablation generator 130 electrically connected to the medical catheter 110 for providing ablation energy to the third electrode 111. The ablation generator 130 can provide ablation energy for the third electrode 111 at the head end of the catheter, and the ablation operation can be directly performed without changing the catheter in the ablation process, so that the operation process is simpler and more convenient.

According to an embodiment of the utility model, the computing processing device 140 comprises an ablation computation module that determines the ablation energy and the ablation duration based on the heart wall thickness values monitored in real time. The ablation calculation module can automatically generate the ablation energy and the ablation duration time required by the ablation of each part based on the wall thickness, and the ablation energy is increased for the position with thicker heart wall, and meanwhile, the longer ablation time is given; the ablation energy is reduced for the position with thinner heart wall, and the ablation time is shortened at the same time, so that the tissue contraction of the position caused by excessive ablation is prevented, the operation complication is caused, or the insufficient ablation is caused, and the operation effect is influenced. After the ablation time and the ablation intensity are displayed on the display system, an operator can more accurately conduct ablation, so that the operation safety and the ablation treatment effect are improved.

The difficulty with ablating target tissue using radio frequency energy is that controlling the local heating of the target tissue requires a tradeoff between creating a large enough ablation focus to effectively ablate abnormal target tissue foci or blocking the adverse effects of abnormal conduction patterns and excessive local heating: if the rf device forms too small an ablation focus, the treatment process may be less effective or may take a long time to cut off the transmission of the abnormal electrical signal, possibly causing localized charring effects, coagulum, or explosive steam pop if the target tissue is excessively heated; if the rf device forms too large an ablation focus, adjacent target tissue may be unintentionally ablated, and in some cases, perforation of the heart wall may occur. The utility model determines the ablation energy and the ablation time based on the heart wall thickness value monitored in real time, thereby achieving the purposes of fully ablating and cutting off abnormal electric signal transmission, and not causing the part to shrink excessively to affect the normal function of the heart.

According to an embodiment of the present utility model, the computing and processing device 140 includes a pressure alarm module, which sets a pressure alarm threshold for the medical catheter 110 and the target ablation site based on the heart wall thickness value monitored in real time, and when the pressure generated by the medical catheter 110 on the target ablation site exceeds the pressure alarm threshold, the computing and processing device 140 issues an alarm. The pressure alarm module sets up different pressure alarm threshold values based on different wall thicknesses, and in the thinner department of heart wall, pressure alarm threshold value is lower, and the thicker department of heart wall sets up higher pressure alarm threshold value, makes the art person support on the heart chamber wall with great contact pressure in this department, carries out abundant ablation to this thicker department of heart chamber wall, and when the pressure that the pipe produced the heart exceeded the pressure alarm threshold value at this position, the system can send out the police dispatch newspaper, suggestion art person pressure is too big, effective control operation risk prevents the heart perforation.

While the utility model has been described in connection with specific embodiments thereof, it is to be understood that these drawings are included in the spirit and scope of the utility model, it is not to be limited thereto.

Claims (8)

1. A calibration matrix generation apparatus for finding tissue thickness, comprising:

an analog catheter having electrodes for generating a local electric field and forming an electrical signal;

an impedance measuring instrument electrically connected with the analog catheter for converting the electrical signal into an impedance value;

the body environment simulation device is used for simulating body environment and is provided with experimental tissues;

the motor control module is used for controlling the simulation catheter to apply pressure to the experimental tissue;

a pressure gauge for measuring a contact pressure value of the applied pressure and transmitting the contact pressure value to a computing processing device;

the calculation processing equipment is electrically connected with the impedance measuring instrument, the pressure measuring instrument and the motor control module, receives the contact pressure value and the impedance value, stores the impedance value, the contact pressure value and the thickness value of the experimental tissue in a data set form, and stores the data sets with different values in a matrix form to form a calibration matrix.

2. The calibration matrix generating device for finding tissue thickness of claim 1, wherein said electrodes comprise a first electrode and a second electrode, said first electrode being disposed at said simulated catheter tip for generating a localized electric field; the second electrode is adjacent to the first electrode for converting the local electric field into the electrical signal.

3. The calibration matrix generating device for finding tissue thickness of claim 1, wherein the motor control module comprises:

a stepping motor;

the control circuit is electrically connected with the stepping motor and controls the stepping motor to move;

the fixed rod is fixedly connected with the stepping motor and the simulation catheter, so that the simulation catheter is parallel to the stepping motor and moves.

4. A calibration matrix generating device for finding tissue thickness according to claim 3, wherein the stepper motor comprises a head and a shaft, the shaft being provided with external threads for threaded connection with the fixation rod.

5. The calibration matrix generating apparatus for finding tissue thickness of claim 1, wherein the volume environment simulation device comprises: a cylinder, a deformed porous plate and a beaker;

the cylinder body is used for storing first brine, the bottom of the cylinder body is provided with a grounding plate, the grounding plate is provided with the deformation porous plate,

the experimental tissue is placed on the deformation porous plate and is used for deforming along with the experimental tissue,

the beaker stores second brine, is connected with the grounding plate through a first wire and is connected with the impedance measuring instrument through a second wire.

6. The calibration matrix generating device for finding a tissue thickness according to claim 5, wherein the cylinder is placed on the pressure gauge having a function of displaying the contact pressure value.

7. The calibration matrix generating device for finding tissue thickness of claim 5, further comprising a circulation pump for controlling the temperature and flow rate of the first saline to simulate human blood.

8. A wall thickness monitoring device, comprising:

a medical catheter in direct contact with the heart wall, comprising an electrode and a pressure sensor;

the electrode is positioned at the head end of the medical catheter and is used for generating a local electric field and converting the local electric field into an electric signal;

the pressure sensor is adjacent to the electrode and is used for measuring the contact pressure value of the medical catheter and the heart wall;

the impedance measuring instrument is electrically connected with the medical catheter and converts the electric signal into an impedance value;

a computing processing device storing a calibration matrix generated by the calibration matrix generating means for finding tissue thickness according to any one of claims 1-7, electrically connected to the medical catheter and the impedance meter, receiving the contact pressure value and the impedance value, and finding in the calibration matrix a data set closest to the contact pressure value and the impedance value, the heart wall thickness in the data set being the monitored heart wall thickness.

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