CN115444547A - Heart wall thickness monitoring device - Google Patents
Heart wall thickness monitoring device Download PDFInfo
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- CN115444547A CN115444547A CN202210981155.2A CN202210981155A CN115444547A CN 115444547 A CN115444547 A CN 115444547A CN 202210981155 A CN202210981155 A CN 202210981155A CN 115444547 A CN115444547 A CN 115444547A
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
- A61B18/04—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
- A61B18/12—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
- A61B18/14—Probes or electrodes therefor
- A61B18/1492—Probes or electrodes therefor having a flexible, catheter-like structure, e.g. for heart ablation
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/05—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves
- A61B5/053—Measuring electrical impedance or conductance of a portion of the body
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/05—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves
- A61B5/053—Measuring electrical impedance or conductance of a portion of the body
- A61B5/0538—Measuring electrical impedance or conductance of a portion of the body invasively, e.g. using a catheter
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/103—Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
- A61B5/107—Measuring physical dimensions, e.g. size of the entire body or parts thereof
- A61B5/1072—Measuring physical dimensions, e.g. size of the entire body or parts thereof measuring distances on the body, e.g. measuring length, height or thickness
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
- A61B5/6846—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be brought in contact with an internal body part, i.e. invasive
- A61B5/6847—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be brought in contact with an internal body part, i.e. invasive mounted on an invasive device
- A61B5/6852—Catheters
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
- A61B5/6846—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be brought in contact with an internal body part, i.e. invasive
- A61B5/6867—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be brought in contact with an internal body part, i.e. invasive specially adapted to be attached or implanted in a specific body part
- A61B5/6869—Heart
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B90/00—Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges
- A61B90/06—Measuring instruments not otherwise provided for
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
- A61B2018/00315—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body for treatment of particular body parts
- A61B2018/00345—Vascular system
- A61B2018/00351—Heart
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
- A61B2018/00636—Sensing and controlling the application of energy
- A61B2018/00773—Sensed parameters
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
- A61B2018/00636—Sensing and controlling the application of energy
- A61B2018/00773—Sensed parameters
- A61B2018/00875—Resistance or impedance
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
- A61B2018/00636—Sensing and controlling the application of energy
- A61B2018/00898—Alarms or notifications created in response to an abnormal condition
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B90/00—Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges
- A61B90/06—Measuring instruments not otherwise provided for
- A61B2090/061—Measuring instruments not otherwise provided for for measuring dimensions, e.g. length
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B90/00—Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges
- A61B90/06—Measuring instruments not otherwise provided for
- A61B2090/064—Measuring instruments not otherwise provided for for measuring force, pressure or mechanical tension
- A61B2090/065—Measuring instruments not otherwise provided for for measuring force, pressure or mechanical tension for measuring contact or contact pressure
Abstract
The invention provides a heart wall thickness monitoring device which comprises a medical catheter directly contacted with a heart wall, an impedance measuring instrument and a computing and processing device stored with a calibration matrix. The medical catheter is used for generating an electric signal and measuring the contact pressure value of the medical catheter in direct contact with the heart wall; the impedance measuring instrument is electrically connected with the medical catheter and converts the electrical signal into an impedance value; the calculation processing equipment is electrically connected with the medical catheter and the impedance measuring instrument, 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 in the data set is the monitored heart wall thickness. The invention realizes the problem of monitoring the tissue thickness of a target ablation part in the ablation operation process in real time at low cost, and can also determine the ablation energy and the ablation duration time of a medical catheter in the ablation process based on the tissue thickness monitored in real time, thereby improving the operation safety and the ablation treatment effect.
Description
Technical Field
The invention relates to the field of medical surgical instruments, in particular to a heart wall thickness monitoring device.
Background
The catheter radio frequency ablation is the most common minimally invasive interventional technique for treating arrhythmia at present, the reason of the arrhythmia is that abnormal electric signal transmission occurs in part of tissues of the heart, the electric signals of the heart are conducted to other adjacent tissues abnormally, thereby the normal heart cycle is interrupted to cause arrhythmia, and the basic principle of the catheter radio frequency ablation is as follows: the radio frequency medical catheter is sent to a target heart cavity through catheters with different lengths, a focus of origin of arrhythmia is accurately positioned under the guidance of a three-dimensional mapping technology, a columnar ablation electrode at the head end of the catheter is contacted with a focus tissue by effective contact pressure, and then radio frequency current is sent through a loop electrode attached to the skin of the body surface of a patient. Radio frequency current flows through lesion tissues below the electrodes through the electrodes to generate heat in the tissues, and when the temperature reaches the degree of coagulation necrosis, the tissues permanently lose electrophysiological activity, thereby cutting off abnormal electric signal transmission, recovering the normal heart cycle and curing arrhythmia.
At present, when a doctor carries out a catheter radio frequency ablation operation on a patient, the wall thickness of a heart target ablation part cannot be obtained in advance, the parts with thinner wall thickness on the heart are ablated, when an operator controls a catheter to enable a columnar ablation electrode at the head end of the catheter to be supported against the target ablation part under effective contact pressure, accidental situations such as heart perforation caused by excessive force easily occur, and the operation safety of the patient is threatened. When a part with a thin heart wall of a patient is ablated, if ablation energy controlled by an operator is too large or ablation time is too long, a target ablation part is over-ablated, a local charring effect is caused, coagula or explosive steam explosion endangers the life of the patient, the part can be contracted, normal beating of the heart is influenced, and if the ablation part is positioned near a blood vessel, the contraction of a blood vessel mouth is caused, so that operation complications such as insufficient blood supply of a human body are generated, and the operation quality is influenced. When the ablation is carried out on a part with thick heart wall of a patient, if the ablation energy controlled by an operator is too small or the ablation time is too short, the ablation of the part is insufficient, the ablation on the side, away from the head end of the medical catheter, of the heart wall is insufficient, the purpose of cutting off the transmission of abnormal electric signals cannot be achieved, and the operation quality is affected.
The prior art proposes a method for measuring tissue thickness using ultrasound and force measurements by inserting a catheter having a distal section into the subject's body and in contact with the wall of a heart chamber, the heart chamber having an inner surface and an outer surface, the distal section of the catheter having a contact pressure sensor and an ultrasound transducer. Actuating the transducer to acquire ultrasonic reflection data from the wall of the cavity, reciprocating the catheter against the wall of the cavity and measuring a contact pressure between the catheter and the wall of the cavity while actuating the transducer, combining the reflection data with the contact pressure, identifying a set of correlated reflection data having a highest correlation with the contact pressure, and determining a tissue thickness between the inner surface and the identified set of the reflection data from a time of flight between the inner surface and the identified set of the reflection data.
According to the technical scheme, the measurement is carried out through tools such as an ultrasonic probe, and the like, and the instruments are expensive and the operation cost is too high.
Disclosure of Invention
The invention aims to solve the problem of how to monitor the tissue thickness of a target ablation part in an ablation operation process in real time at low cost. Meanwhile, the invention determines the ablation energy and the ablation duration time of the medical catheter in the ablation process based on the tissue thickness monitored in real time, and sets the contact pressure alarm threshold value of the medical catheter and the target ablation part. After the numerical values are fed back to an operator through the display device, the operator can more accurately perform ablation, so that the operation safety degree and the ablation treatment effect are improved.
The invention provides a heart wall thickness monitoring device, comprising: the device comprises a medical catheter directly contacting with the heart wall, an impedance measuring instrument and a calculation processing device storing a calibration matrix. Wherein the medical catheter is in direct contact with the heart wall and is used for generating an electric signal and measuring the contact pressure value of the medical catheter in direct contact with the heart wall; the impedance measuring instrument is electrically connected with the medical catheter and converts the electrical signal into an impedance value; and the calculation processing equipment stores a calibration matrix, is electrically connected with the medical catheter and the impedance measuring instrument, 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 in the data set is the monitored heart wall thickness.
According to an embodiment of the present invention, the calibration matrix is generated by a calibration matrix generating device, which includes: the device comprises a body environment simulation device, a simulation conduit, an impedance measuring instrument, a pressure measuring instrument, a motor control module and a calculation processing device. Wherein, the environmental simulation equipment includes: a cylinder body, a deformation porous plate and a beaker. The first salt water of cylinder body storage, its bottom is provided with the ground plate, is provided with the deformation perforated plate on the ground plate, places the experimental organization on the deformation perforated plate for take place deformation along with the experimental organization. The beaker stores a second brine, which is connected to the ground plate by a conduit.
The analog catheter has electrodes for generating local electric fields and forming electrical signals. The impedance measuring instrument is electrically connected with the analog conduit and converts the electric signal into an impedance value. And the motor control module controls the simulation catheter to apply pressure to the experimental tissue. And the pressure measuring instrument is used for measuring and displaying the contact pressure value of the applied pressure and transmitting the contact pressure value to the calculation processing equipment. And the calculation processing equipment is electrically connected with the impedance measuring instrument, the pressure measuring instrument and the motor control module, and is used for receiving the contact pressure value, the impedance value, the type of the experimental tissue and the thickness value of the experimental tissue to form a calibration matrix.
According to an embodiment of the present invention, 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; and 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 an embodiment of the present invention, the generating means of the calibration matrix further comprises a circulation pump controlling the temperature and flow rate of the first saline to simulate human blood.
According to the embodiment of the invention, the medical catheter is provided with electrodes, wherein the electrodes comprise a first electrode and a second electrode, and the first electrode is arranged at the head end of the medical catheter and used for generating a local electric field; the second electrode is adjacent to the first electrode and converts the local electric field into an electric signal.
According to an embodiment of the invention, the medical catheter has a pressure sensor for measuring a contact pressure value of the medical catheter with the heart wall.
According to an embodiment of the invention, the computational processing device comprises an ablation computation module that determines the ablation energy and ablation duration based on the real-time monitored heart wall thickness.
According to the embodiment of the invention, the calculation processing equipment comprises a pressure alarm module, a pressure alarm threshold value of the medical catheter and the target ablation part is set based on the monitored heart wall thickness value, and when the pressure generated by the medical catheter to the target ablation part exceeds the pressure alarm threshold value, the calculation processing equipment gives an alarm.
According to an embodiment of the invention, the medical catheter of the invention is an ablation catheter.
According to an embodiment of the present invention, the cardiac wall thickness monitoring device further comprises an ablation generator electrically connected to the ablation catheter for providing ablation energy to the ablation catheter.
Before the ablation operation, the operator can't obtain the heart chamber wall thickness that patient's heart chamber target melts the position, also can't the ablation energy and the ablation time that accurate control medical catheter sent, and traditional heart wall thickness measuring device all measures through instruments such as sensor and ultrasonic probe, and this type of apparatus is all more expensive often, and the operation cost is too high. The invention can complete the measurement of the heart wall thickness by utilizing the conventional pressure catheter, thereby reducing the operation cost. The invention is provided with a pressure alarm threshold, ablation energy and ablation time based on the tissue wall thickness, so that the operation process is safer and more efficient. Meanwhile, the calibration matrix generation device provided by the invention establishes a calibration matrix of the contact pressure value and the impedance value of the catheter and target tissues of different tissue types and different tissue thicknesses. Through the calibration matrix, in the ablation process, the calculation processing equipment compares the tissue contact pressure and the impedance value of the medical catheter in the ablation process with the data in the calibration matrix, the wall thickness displayed by the closest group of data is the thickness of the tissue of the catheter contact part, no additional ultrasonic equipment is needed, and the operation cost is greatly reduced.
Drawings
FIG. 1 is a schematic view of a real-time cardiac wall thickness monitoring apparatus according to an embodiment of the present invention;
FIG. 2 is a schematic illustration of a medical catheter according to an embodiment of the present invention moving to cause distortion of a local electric field;
FIG. 3 is a schematic diagram of a calibration matrix generation apparatus according to an embodiment of the invention;
FIG. 4 is a schematic illustration of a simulated catheter applying pressure to a test tissue in accordance with an embodiment of the present invention.
Reference numerals
A medical catheter 110, a first electrode 111, a second electrode 112, a pressure sensor 113, an impedance meter 120, an ablation generator 130, a computing processing device 140, an electrode patch 150,
the calibration matrix generating means 200 is adapted to generate a calibration matrix,
a simulated conduit 210, a third electrode 211, a fourth electrode 212,
a cylinder 220, a grounding plate 221, a deformable porous plate 222, a gasket 223, a first brine 224,
the contents of the beaker 230, the second brine 231,
a stepping motor 241, a head 2411, a rod 2412, a motor control circuit 242, a fixing rod 243,
the circulation pump (250) is driven by the motor,
the pressure gauge (260) is set in the pressure gauge,
Detailed Description
To further explain the technical means and effects of the present invention adopted to achieve the intended purpose, the present invention will be described in detail with reference to the accompanying drawings and preferred embodiments.
As shown in fig. 1, the device for monitoring the wall thickness of the heart in real time provided by the invention comprises: a medical catheter 110, an impedance meter 120, and a computing and processing device 140.
The medical catheter 110 is in direct contact with the heart wall and is configured to generate an electrical signal and measure a contact pressure value of the medical catheter 110 in direct contact with the heart wall, and the impedance measuring instrument 120 is electrically connected to the medical catheter 110 and converts the electrical signal into an impedance value. The impedance meter 120 includes a conventional filter (band pass filter) to block the passage of signals that are not of interest, but to allow signals of appropriate frequency to pass, such as the excitation frequency, and conventional signal processing software to obtain the impedance R of the signal under test.
The calculation processing device 140 stores a calibration matrix, is electrically connected to the medical catheter 110 and the impedance measuring instrument 120, receives the contact pressure values and the impedance values, and searches a data set closest to the contact pressure values and the impedance values in the calibration matrix, wherein the heart wall thickness in the data set is the monitored heart wall thickness.
According to an embodiment of the present invention, the calibration matrix is generated by a calibration matrix generating apparatus 200, the calibration matrix generating apparatus 200 includes: a body environment simulation apparatus, a simulation catheter 210, an impedance meter 120, a pressure meter 260, a motor control module, and a computing processing apparatus 140.
Wherein, the body environment simulation equipment includes: a cylinder 220, a deformable porous plate 222, and a beaker 230. The tank body stores first salt water 224, and its bottom is provided with ground plate 221, is provided with deformation perforated plate 222 on the ground plate 221, places the experimental organization on the deformation perforated plate 222 for take place the deformation along with the experimental organization. The beaker 230 stores a second brine, which is connected to the ground plate 221 by a wire. Specifically, as shown in fig. 3, a first saline 224 for simulating blood is contained in the cylinder 220, a grounding plate 221 is provided at the bottom of the cylinder 220, the grounding plate 221 is connected to a beaker 230 for acting as a series resistor by 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 saline salinity, so that the whole circuit has an impedance similar to that of a human body. The grounding plate 221 is provided with a deformable porous plate 222 supported by a gasket 223, an experimental tissue 300 to be tested is placed on the deformable porous plate 222, and the deformable porous plate 222 can deform synchronously with the experimental tissue 300.
The analog conduit 210 has electrodes for generating local electric fields and forming electrical signals. The impedance meter 120 is electrically connected to the analog conduit 210, and converts 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 simulated catheter 210 contacts the experimental tissue 300 and continuously applies a downward pressure to make the experimental tissue 300 deform concavely, the local electric field generated by the third electrode 211 of the simulated catheter 210 changes, the fourth electrode 212 of the simulated catheter 210 senses the change of the local electric field, and the impedance measuring instrument 120 converts the electric signal acquired by the fourth electrode 212 into an impedance value, where the impedance value changes with the change of the local electric field.
And a motor control module for controlling the simulated catheter 210 to apply pressure to the experimental tissue.
And the pressure measuring instrument 260 is used for measuring and displaying the contact pressure value of the applied pressure and transmitting the contact pressure value to the calculation processing equipment. In fig. 3, the pressure gauge 260 records and displays the contact pressure value, and the numerical scale is in grams.
And the calculation processing equipment 140 is electrically connected with the impedance measuring instrument 120, the pressure measuring instrument 260 and the motor control module, and receives the contact pressure value, the impedance value, the type of the experimental tissue and the thickness value of the experimental tissue to form a calibration matrix.
According to an embodiment of the present invention, 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; and a fixing rod 243 for fixedly connecting the stepping motor 241 and the simulation catheter 210 such that the simulation catheter 210 is parallel to the stepping motor 241 and moves. As shown in fig. 3, an operator sends an instruction to the calculation processing device 140, the calculation processing device 140 transmits the instruction to the motor control circuit 242, the motor control circuit 242 is connected to 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 to the analog conduit 210 through a fixing rod 243 to control the up-and-down movement of the analog conduit 210 within a millimeter range. The distance the simulated catheter 210 moves down is recorded by the stepper motor 241 control circuitry and sent to the computing and processing device 140.
The stepping motor 241 includes a head 2411 and a shaft 2412, and the shaft 2412 is threadedly coupled to an internal thread provided at one end of the fixing rod 243 via an external thread. The motor control circuit 242 controls the operation of the stepping motor 241, and the rod 2412 of the stepping motor rotates to drive the fixing rod 243 screwed with the rod 2412 to move up or down integrally, so that the simulation catheter 210 moves up and down along with the fixing rod.
Each time the simulated conduit 210 is moved downward, the stepper motor 241 control circuitry sends the simulated conduit 210 downward displacement Δ X in mm to the computing and processing device 140. The calculation processing device 140 records and stores the contact pressure value F and the impedance value R transmitted by the impedance measuring instrument 120 into the calibration matrix. Each downward movement of the simulated catheter 210 results in a corresponding set of displacement ax and corresponding resistance R and force F values, and all of the recorded information for each set of tests is stored in the calibration matrix along with the known thickness of the experimental tissue 300. This operation is repeated for different types of test tissues 300 and different thicknesses of the test tissues 300, with which force values and resistance values R are collected, thereby forming a calibration matrix consisting of the type of test tissue 300, the thickness of the test tissue 300, the displacement, 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 value of each element being storable in an interval value when stored, e.g. the values of 3 elements may be stored in a { [ a1, a2], [ b1, b2], [ c1, c2] } manner or in a { [ a1, ±. DELTA.a 0], [ b1,. DELTA.b 0], [ c1,. DELTA.c 0] } manner when stored in the calibration matrix.
As shown in fig. 4, the same force F is applied orthogonally to two different thicknesses of the test tissue 300, where the thinner thickness of the test tissue 300 is t1, resulting in a displacement Δ X1, and the thicker thickness of the test tissue 300 is t2, resulting in a displacement Δ X2, where Δ X1 > Δ X2, and where the two different displacements result in different impedance values.
The displacement Δ X and impedance value of the medical catheter 110 against the target tissue are derived as follows. In the myocardium and blood, the distribution of current is not simple because of the geometry and relationship of many materials (e.g., myocardium, blood, bone, and skin). This problem can be illustrated by a metal ball of diameter r1, which is surrounded by several other ball 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
Where ρ is n Is the resistivity of the nth ring. If ρ n All equal to p, which means the same material, the above equation reduces to equation 2:
since the resistivity of blood is less than that of the myocardium, when the medical catheter 110 penetrates the myocardium, the near potential field around the tip electrode is greatly distorted, and more area of the tip electrode is surrounded by the higher resistivity myocardium. Because, as the tip electrode penetrates into the target tissue, the impedance increases rapidly. Monitoring the impedance Z of the medical catheter 110 electrode can give a predicted displacement of the tip electrode into the target tissue. However, in order to predict penetration of the medical catheter 110 into the target tissue, some assumptions may be considered as the process of current flowing through the earth ground through the ground rod, and 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 the gauge of medical catheter 110 c The value is obtained.
From the above equation, a calculated relationship between the displacement Δ X of the medical catheter 110 against the target tissue and the impedance can be derived, and the displacement Δ X of the medical catheter 110 against the target tissue is proportional to the impedance value.
The operator can use the medical catheter 110 to properly touch the target tissue and transmit the signal sensed by the second electrode 112 back to the impedance measuring instrument 120 to convert the signal into an impedance value, and the force F applied to the target tissue by the medical catheter 110 can be directly measured by the pressure sensor 113 of the medical catheter 110. The calculation processing device 140 can automatically match in the calibration matrix according to the obtained impedance value and the force F applied by the medical catheter 110 to the target tissue, and obtain the tissue thickness in the group of data sets with the impedance value closest to the force F applied by the medical catheter 110 to the target tissue, that is, the thickness of the target tissue.
The calibration matrix generating device 200 further comprises a circulation pump 250, the circulation pump 250 controlling the temperature and flow rate of the first saline 224 to simulate human blood, according to an embodiment of the present invention.
According to the embodiment of the invention, the medical catheter is provided with electrodes, wherein the electrodes comprise a first electrode 111 and a second electrode 112, the first electrode 111 is arranged at the head end of the medical catheter and generates a local electric field; the second electrode 112 is adjacent to the first electrode 111, and converts 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, due to different resistivities of blood and the target tissue, the local electric field generated by the first electrode 111 at the head end of the medical catheter 110 changes with the movement of the medical catheter 110, and the local electric field is distorted due to the contact of the medical catheter 110 and the high resistivity myocardium, as shown in fig. 2, 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 second electrode 112 senses and transmits the above-mentioned electric field change back to the computing processing device 140, and the impedance measuring instrument 120 converts the sensed electric signal into impedance and transmits the impedance to the computing processing device 140.
According to an embodiment of the present invention, the medical catheter 110 has a pressure sensor 113 for measuring a contact pressure value of the medical catheter 110 with the heart wall.
According to an embodiment of the invention, the computational processing device comprises an ablation computation module that determines an ablation energy and an ablation duration based on the monitored cardiac wall thickness. The ablation calculation module can automatically generate ablation energy and ablation duration time required by ablation of each part based on the wall thickness, increase the ablation energy for the position with thicker heart wall and simultaneously give out longer ablation time; 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 situation that the tissue of the position shrinks due to excessive ablation to cause operation complications is prevented, or the operation effect is influenced due to insufficient ablation. After the ablation time and the ablation intensity are displayed on the display system, an operator can more accurately perform ablation, so that the operation safety and the ablation treatment effect are improved.
The difficulty in ablating target tissue using radiofrequency energy is controlling the local heating of the target tissue, requiring a trade-off between creating a large enough lesion to effectively ablate an abnormal target tissue focus or block abnormal conduction patterns and the undesirable effects of excessive local heating: if the radiofrequency device forms too small a lesion, the treatment process may be less effective, or it may take a long time to cut off the transmission of abnormal electrical signals, which may cause localized charring effects, coagulum, or explosive steam pop if the target tissue is overheated; if the radiofrequency device forms too large a lesion, the adjacent target tissue may be inadvertently ablated, and in some cases, perforation of the heart wall may occur. The invention determines the ablation energy and the ablation time length based on the heart wall thickness value monitored in real time, thereby achieving the purposes of fully ablating and cutting off the transmission of abnormal electric signals and not causing the contraction of the part to influence the normal function of the heart due to excessive ablation.
According to an embodiment of the present invention, the computing device 140 includes a pressure alarm module that sets a pressure alarm threshold for the medical catheter 110 and the target ablation site based on the monitored heart wall thickness value. The computing and processing device 140 issues an alarm when the pressure generated by the medical catheter 110 to the target ablation site exceeds a pressure alarm threshold. The pressure alarm module sets up different pressure alarm threshold values based on different wall thicknesses, in the thinner department of heart wall, pressure alarm threshold value is lower, in the thicker department of heart wall, set up higher pressure alarm threshold value, make the art person support by on heart chamber wall with great contact pressure in this department, fully melt this heart chamber wall thicker department, when the pressure that the pipe produced the heart surpassed the pressure alarm threshold value at this position, the system can send out the police dispatch newspaper, indicate that art person's pressure is too big, effective control operation risk, prevent the heart perforation.
Specifically, as shown in fig. 1, during the ablation, the body is attached with an electrode patch 150 serving as a ground wire to complete the current reflux of the system, the signal generator generates a low amplitude signal to excite the first electrode 111 at the head end of the medical catheter 110, thereby generating a local electric field at the head end of the medical catheter 110, the second electrode 112 is used for sensing the local electric field generated by the first electrode 111 and transmitting the sensed electric signal to the impedance measuring instrument 120 through a suitable lead, and converting the electric signal sensed by the second electrode 112 into an impedance value, the impedance value is transmitted to the calculation processing device 140 through a lead, the calculation 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 obtained from the pressure sensor 113 and a calibration matrix stored in the CPU, the tissue wall thickness in a set of data closest to the obtained contact pressure value and impedance value is the wall thickness value closest to the target tissue in contact with the medical catheter 110, the CPU finally stores the data in an internal memory and transmits the data to the display system, and the display system obtains the target tissue wall thickness value against the target catheter.
The medical catheter 110 of the present invention is an ablation catheter in accordance with an embodiment of the present invention. In the ablation process, the catheter does not need to be replaced to directly carry out the ablation operation, so that the operation process is simpler and more convenient.
According to an embodiment of the present invention, the device for monitoring the wall thickness of the heart in real time further comprises an ablation generator 130 electrically connected to the ablation catheter for providing ablation energy to the ablation catheter. The ablation generator 130 can provide ablation energy for the first electrode 111 at the head end of the catheter, and in the ablation process, the ablation operation can be directly carried out without replacing the catheter, so that the operation process is simpler and more convenient.
While the invention has been described in connection with specific embodiments thereof, it is to be understood that it is intended by the appended drawings and description that the invention may be embodied in other specific forms without departing from the spirit or scope of the invention.
Claims (10)
1. A cardiac wall thickness monitoring apparatus, comprising:
a medical catheter in direct contact with a heart wall for generating an electrical signal and measuring a contact pressure value of the medical catheter in direct contact with the heart wall;
the impedance measuring instrument is electrically connected with the medical catheter and converts the electric signal into an impedance value;
and the calculation processing equipment is used for storing a calibration matrix, is electrically connected with the medical catheter and the impedance measuring instrument, 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 in the data set is the monitored heart wall thickness.
2. The cardiac wall thickness monitoring apparatus according to claim 1, wherein the calibration matrix is generated by a calibration matrix generating means, the calibration matrix generating means including:
a body environment simulation apparatus comprising: a cylinder body, a deformation porous plate and a beaker,
the tank body is used for storing first brine, the bottom of the tank body is provided with a grounding plate, the grounding plate is provided with the deformation porous plate,
the deformation perforated plate is provided with an experimental tissue for deforming along with the experimental tissue,
the beaker storing a second brine, which is connected with the grounding plate through a conduit;
an analog catheter having electrodes for generating a local electric field and forming an electrical signal;
the impedance measuring instrument is electrically connected with the analog conduit and converts the electric signal into an impedance value;
a motor control module for controlling the simulated catheter to apply pressure to the experimental tissue;
the pressure measuring instrument is used for measuring and displaying the contact pressure value of the applied pressure and transmitting the contact pressure value to the computing and processing equipment;
and the calculation processing equipment is electrically connected with the impedance measuring instrument, the pressure measuring instrument and the motor control module, and is used for receiving the contact pressure value, the impedance value, the type of the experimental tissue and the thickness value of the experimental tissue to form a calibration matrix.
3. The cardiac wall thickness monitoring apparatus according to claim 2, wherein said motor control module comprises:
a stepping motor;
the control circuit is electrically connected with the stepping motor and controls the stepping motor to move;
and 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. The cardiac wall thickness monitoring apparatus according to claim 2, wherein the calibration matrix generating means further comprises a circulation pump for controlling the temperature and flow rate of the first saline to simulate human blood.
5. The cardiac wall thickness monitoring device according to claim 1, wherein the medical catheter has electrodes, the electrodes including a first electrode and a second electrode, the first electrode being disposed at a tip end of the medical catheter for generating a local electric field; the second electrode is adjacent to the first electrode for converting the local electric field into the electrical signal.
6. The cardiac wall thickness monitoring apparatus according to claim 1, wherein the medical catheter has a pressure sensor for measuring the contact pressure value of the medical catheter with the cardiac wall.
7. The cardiac wall thickness monitoring apparatus according to claim 1, wherein the calculation processing device includes an ablation calculation module that determines an ablation energy and an ablation time period based on the monitored cardiac wall thickness.
8. The cardiac wall thickness monitoring apparatus according to claim 1, wherein the calculation processing device includes a pressure alarm module, determines a pressure alarm threshold value between the medical catheter and a target ablation site based on the monitored cardiac wall thickness value, and issues an alarm when the pressure generated by the medical catheter to the target ablation site exceeds the pressure alarm threshold value.
9. The cardiac wall thickness monitoring apparatus according to any one of claims 1-8, wherein the medical catheter is an ablation catheter.
10. The cardiac wall thickness monitoring device according to claim 9, wherein said real-time cardiac wall thickness monitoring device further comprises an ablation generator electrically connected to said ablation catheter for providing ablation energy to said ablation catheter.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210981155.2A CN115444547A (en) | 2022-08-16 | 2022-08-16 | Heart wall thickness monitoring device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210981155.2A CN115444547A (en) | 2022-08-16 | 2022-08-16 | Heart wall thickness monitoring device |
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| CN115444547A true CN115444547A (en) | 2022-12-09 |
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| CN202210981155.2A Pending CN115444547A (en) | 2022-08-16 | 2022-08-16 | Heart wall thickness monitoring device |
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