Method and system for electrode-to-tissue contact recognition

Abstract

A method and system for electrode and tissue contact identification are disclosed. In the method (700) for electrode and tissue contact identification, impedances between electrodes on a body cavity invasive device are acquired at different frequencies (S710). According to the acquired impedances between the electrodes, impedance frequency response coefficients between the electrodes are determined (S720). According to the impedance frequency response coefficients, a contact condition of the electrodes and tissue in a body cavity is determined (S730). The body cavity invasive device of the present invention comprises a catheter. A plurality of electrodes are provided on a distal end of the invasive catheter. The contact condition comprises whether the electrodes are in contact with a body cavity surface and a degree of contact.

Description

Technical Field

[0001] This invention relates to electrophysiological ablation and circuitry, specifically to a method and system for identifying electrode-tissue contact. Background Technology

[0002] Currently, medical 3D positioning systems often involve locating one or more invasive devices and determining the relative position of the invasive device to the tissue being treated. For example, in practice, it is necessary to locate invasive devices within body cavities, and in particular, to identify the contact between the invasive device and the surface of the body cavity. Generally, it is necessary to assess the contact between invasive devices within the heart chambers or renal arteries and the surface of the body cavity. More specifically, it is necessary to verify whether the invasive device is in contact with the tissue.

[0003] Three-dimensional positioning systems with contact indication capabilities can more accurately reflect the relative positional relationship between the invasive device and the endothelial surface of the body cavity. Applications of contact indication in medical three-dimensional positioning systems include contact indication between the catheter and the wall of the heart chamber and / or the wall of a blood vessel, and contact indication between the catheter and the inner wall of the renal artery.

[0004] Common invasive devices include, for example, catheters, sheaths, and puncture needles fitted with one or more positioning electrodes. Catheters can be classified by shape, including, for example, basket-shaped catheters, balloon-shaped catheters, coil-shaped catheters, petal-shaped catheters, grid-shaped catheters, and thread-shaped catheters.

[0005] Therefore, there is a need for a method and system that is easy to operate in practice to determine the relative position and degree of contact between an invasive device and the tissue to be treated. Summary of the Invention

[0006] The purpose of this invention is to provide a system and method for locating intracavitary invasive devices, particularly relating to a method and system for identifying contact between an invasive device and a body cavity surface, and non-exclusively relating to a method and system for assessing contact between an invasive device and a body cavity surface within the cardiac or renal artery. The invasive devices designed in this invention non-exclusively involve basket-shaped, balloon-shaped, ring-shaped, petal-shaped, grid-shaped, and linear invasive devices employing similar principles.

[0007] According to a first aspect of the present invention, a method for identifying electrode-tissue contact is provided. The method according to the first aspect of the present invention may include: acquiring impedance between electrodes on a body cavity intrusion device at different frequencies; determining an impedance frequency response coefficient between the electrodes based on the acquired impedance; and determining the contact condition between the electrodes and tissue within the body cavity based on the impedance frequency response coefficient.

[0008] Preferably, the electrode includes a working electrode and a reference electrode. In the method according to the first aspect of the invention, the acquisition of impedance between the electrodes at different frequencies may include: acquiring impedance between working electrodes, between reference electrodes, and between the working electrode and the reference electrode at different frequencies.

[0009] Preferably, the working electrode may include an ablation electrode.

[0010] In the method according to the first aspect of the present invention, preferably, determining the contact between the electrode and the tissue within the body cavity may include: determining the contact between the working electrode and the tissue within the body cavity.

[0011] Preferably, the body cavity intrusion device may include a catheter, with the electrode disposed at the distal end of the catheter.

[0012] Preferably, the catheter may include at least one of the following: basket-shaped catheter, balloon-shaped catheter, coil-shaped catheter, petal-shaped catheter, grid-shaped catheter, and linear catheter.

[0013] Preferably, the different frequencies can be selected based on the different degrees to which different tissue impedances respond to frequency.

[0014] Preferably, the frequency range of the different frequencies can be from 500Hz to 100kHz.

[0015] Preferably, the different frequencies can be two different frequencies.

[0016] In the method according to the first aspect of the present invention, determining the impedance frequency response coefficient between the electrodes may include: calculating the impedance frequency response coefficient between the working electrodes and the impedance frequency response coefficient between the reference electrodes according to equations (1) and (2), respectively.

[0017] The impedance frequency response coefficient Coef between working electrodes i and j ij for:

[0018]

[0019] The impedance frequency response coefficient Coef between reference electrodes m and n mn for:

[0020]

[0021] The determination of the contact between the electrode and the tissue within the body cavity may include: calculating the contact index CI between the working electrodes i and j and the tissue according to equation (3):

[0022]

[0023] In equations (1), (2), and (3) above, This represents the impedance measured between working electrodes i and j at the first frequency Fr1. This represents the impedance measured between working electrodes i and j at the second frequency Fr2. Let represent the real part of the complex impedance measured between working electrodes i and j at the first frequency Fr1. Let represent the real part of the complex impedance measured between working electrodes i and j at the second frequency Fr2. This represents the imaginary part of the complex impedance measured between working electrodes i and j at the first frequency Fr1. This represents the imaginary part of the complex impedance measured between working electrodes i and j at the second frequency Fr2. This represents the impedance measured between reference electrodes m and n at the first frequency Fr1. This represents the impedance measured between reference electrodes m and n at the second frequency Fr2. Let represent the real part of the complex impedance measured between reference electrodes m and n at the first frequency Fr1. Let represent the real part of the complex impedance measured between reference electrodes m and n at the second frequency Fr2. This represents the imaginary part of the complex impedance measured between reference electrodes m and n at the first frequency Fr1. a represents the imaginary part of the complex impedance measured between reference electrodes m and n at the second frequency Fr2. ij b ij c ij a mn b mn c mn Base is the weighting coefficient. ij Base is the base of the frequency response between working electrodes i and j. mn As the base of the frequency response between reference electrodes m and n, Dis ij Dis is the distance between working electrodes i and j. mn The distance between reference electrodes m and n is denoted as m.

[0024] Preferably, the Base ij Parameters and the Base mn The parameters can be related to the Dis ij Parameters and the Dis mn The parameters are correlated.

[0025] Preferably, the Base ij Parameters and the Base mn The parameters can be obtained by referring to Dis ij Parameters and the Dis mnThe parameters, electrode width parameter, and electrode diameter parameter were obtained through high-order regression modeling analysis.

[0026] Preferably, the weighting coefficient a ij b ij c ij a mn b mn c mn The magnitude of reflects the weights of the impedance, capacitive reactance, and combined RC characteristics of the tissue or blood between electrodes in the application environment, where a ij +b ij +c ij =1, a mn +b mn +c mn =1.

[0027] In a method according to a first aspect of the invention, preferably, the method may further include: displaying the contact between the electrode and tissues within the body cavity through color differences.

[0028] According to a second aspect of the present invention, a system for identifying electrode-tissue contact is provided. The system may include: a data acquisition unit for acquiring impedance between electrodes on a body cavity intrusion device at different frequencies; an impedance frequency response coefficient determination unit for determining an impedance frequency response coefficient between the electrodes based on the acquired impedance; and a contact condition determination unit for determining the contact condition between the electrodes and tissue within the body cavity based on the impedance frequency response coefficient.

[0029] Preferably, the electrodes may include a working electrode and a reference electrode. In the system according to the second aspect of the invention, the acquisition unit may be configured to acquire impedances between working electrodes, between reference electrodes, and between the working electrode and the reference electrode at different frequencies.

[0030] Preferably, the working electrode may include an ablation electrode.

[0031] In the system according to the second aspect of the invention, preferably, the contact condition determination unit can be configured to determine the contact condition between the working electrode and the tissue within the body cavity.

[0032] Preferably, the body cavity intrusion device may include a catheter, with the electrode disposed at the distal end of the catheter.

[0033] Preferably, the catheter may include at least one of the following: basket-shaped catheter, balloon-shaped catheter, coil-shaped catheter, petal-shaped catheter, grid-shaped catheter, and linear catheter.

[0034] Preferably, the different frequencies can be selected based on the different degrees to which different tissue impedances respond to frequency.

[0035] Preferably, the frequency range of the different frequencies can be from 500Hz to 100kHz.

[0036] Preferably, the different frequencies can be two different frequencies.

[0037] In the system according to the second aspect of the present invention, the impedance frequency response coefficient determining unit may be configured to: calculate the impedance frequency response coefficient between the working electrodes and the impedance frequency response coefficient between the reference electrodes according to equations (1) and (2), respectively:

[0038] The impedance frequency response coefficient Coef between working electrodes i and j ij for:

[0039]

[0040] The impedance frequency response coefficient Coef between reference electrodes m and n mn for:

[0041]

[0042] The contact condition determination unit can be configured to calculate the contact index CI between the working electrodes i and j and the tissue according to equation (3):

[0043]

[0044] In equations (1), (2), and (3) above, This represents the impedance measured between working electrodes i and j at the first frequency Fr1. This represents the impedance measured between working electrodes i and j at the second frequency Fr2. Let represent the real part of the complex impedance measured between working electrodes i and j at the first frequency Fr1. Let represent the real part of the complex impedance measured between working electrodes i and j at the second frequency Fr2. This represents the imaginary part of the complex impedance measured between working electrodes i and j at the first frequency Fr1. This represents the imaginary part of the complex impedance measured between working electrodes i and j at the second frequency Fr2. This represents the impedance measured between reference electrodes m and n at the first frequency Fr1. This represents the impedance measured between reference electrodes m and n at the second frequency Fr2. Let represent the real part of the complex impedance measured between reference electrodes m and n at the first frequency Fr1. Let represent the real part of the complex impedance measured between reference electrodes m and n at the second frequency Fr2. This represents the imaginary part of the complex impedance measured between reference electrodes m and n at the first frequency Fr1. a represents the imaginary part of the complex impedance measured between reference electrodes m and n at the second frequency Fr2. ij b ij c ij a mn b mn c mn Base is the weighting coefficient. ij Base is the base of the frequency response between working electrodes i and j. mn As the base of the frequency response between reference electrodes m and n, Dis ij Dis is the distance between working electrodes i and j. mn The distance between reference electrodes m and n is denoted as m.

[0045] Preferably, the Base ij Parameters and the Base mn The parameters can be related to the Dis ij Parameters and the Dis mn The parameters are correlated.

[0046] Preferably, the Base ij Parameters and the Base mn The parameters can be obtained by referring to Dis ij Parameters and the Dis mn The parameters, electrode width parameter, and electrode diameter parameter were obtained through high-order regression modeling analysis.

[0047] Preferably, the weighting coefficient a ij b ij c ij a mn b mn c mn The magnitude of reflects the weights of the impedance, capacitive reactance, and combined RC characteristics of the tissue or blood between electrodes in the application environment, where a ij +b ij +c ij =1, a mn +b mn +c mn =1.

[0048] In a system according to a second aspect of the invention, preferably, the system may further include a display unit for displaying the contact between the electrode and tissue within the body cavity through color differences.

[0049] According to a third aspect of the invention, a computer-readable medium is provided having instructions stored thereon that are executable by a processor, which, when executed by the processor, cause the processor to perform a method for identifying electrode-tissue contact as described in the first aspect of the invention.

[0050] This invention discloses a method and system for identifying contact between an invasive device and the surface of a body cavity in the field of intracavitary invasive device positioning. The system includes an invasive catheter with several electrodes disposed distally. The system acquires impedance information of the electrodes relative to a reference at multiple frequencies, obtains the frequency response coefficient of the electrodes based on the impedance information at multiple frequencies, and obtains the contact index (or abutment index) CI based on the frequency response coefficient. CI indicates whether the electrodes are in contact with the surface of the body cavity and the degree of contact. Attached Figure Description

[0051] This disclosure includes accompanying drawings, which are to be considered as included in and form part of the specification, and together with the specification illustrate various exemplary embodiments, features, and aspects of the disclosure and serve to explain the principles of the disclosure. The invention will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, wherein similar elements are numbered in a similar manner. Wherein:

[0052] Figure 1 The relative permittivity of blood, blood vessels, and the heart at different frequencies is shown.

[0053] Figure 2 The conductivity of blood, blood vessels, and the heart at different frequencies is shown.

[0054] Figure 3A This is a schematic diagram of a ring-shaped invasive catheter.

[0055] Figure 3B This is a schematic diagram of the application of a ring-shaped invasive catheter.

[0056] Figure 4A This is a schematic diagram of a petal-shaped invasive duct.

[0057] Figure 4B This is a schematic diagram of the application of petal-shaped invasive catheters.

[0058] Figure 5 This is a flowchart of a method for identifying electrode-tissue contact according to a preferred embodiment of the present invention.

[0059] Figure 6 This is a schematic diagram showing the display of contact recognition results.

[0060] Figure 7 This is a flowchart of a method for identifying electrode-tissue contact according to an embodiment of the present invention.

[0061] Figure 8This is a schematic block diagram of an electrode-tissue contact recognition system according to an embodiment of the present invention. Detailed Implementation

[0062] The technical solution of the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings, but the present invention is not limited to the following embodiments.

[0063] Various exemplary embodiments, features, and aspects of this disclosure will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0064] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0065] Furthermore, to better illustrate this disclosure, numerous specific details are set forth in the following detailed description. Those skilled in the art will understand that this disclosure can be practiced without certain specific details. In some instances, methods, means, components, and circuits well known to those skilled in the art have not been described in detail in order to highlight the main points of this disclosure.

[0066] In summary, this invention provides a method and system for identifying electrode-tissue contact. The method and system are based on the principle that different biological tissues have different impedance responses to frequency.

[0067] Because impedance is involved, it needs to be acquired, or measured. In the following text, the terms "acquisition" and "measurement" are used interchangeably. Acquiring impedance or measuring impedance means obtaining the numerical value of the impedance.

[0068] Impedance acquisition methods can include, but are not limited to, acquiring impedance between electrodes, impedance between an electrode and a reference, or impedance between references at different frequencies. Here, "electrode" refers to the electrode on the invasive device, such as an ablation electrode, mapping electrode, etc., and more specifically, the working electrode that performs the actual treatment or detection function. The reference can be ground level or a reference level outside the body cavity. The reference can also be a reference electrode. In the following text, to distinguish between electrodes and references, electrodes can be divided into two categories: working electrodes and reference electrodes. When using an invasive device for treatment, the working electrode on the invasive device can also be called the treatment electrode. Therefore, the acquisition of impedance at different frequencies can be explained in more detail as: acquiring impedance between working electrodes, between reference electrodes, and between working electrodes and reference electrodes at different frequencies.

[0069] As described above, when the invasive device is an ablation catheter, the working electrode can be an ablation electrode.

[0070] In embodiments where the intracavitary invasive device is a catheter, both the working electrode and the reference electrode can be located at the distal end of the catheter. In some embodiments, the reference electrode can be located at other locations, such as outside the body.

[0071] The catheter can be any one or more of the following: basket-shaped catheter, balloon-shaped catheter, coil-shaped catheter, petal-shaped catheter, grid-shaped catheter, or linear catheter.

[0072] According to the present invention, the acquired impedance information is used to solve for the frequency response coefficient of the electrodes. In a preferred embodiment, the frequency response coefficient of the electrodes includes the frequency response coefficient between the working electrodes and the frequency response coefficient between the reference electrodes.

[0073] Based on the frequency response coefficient of the electrode, the contact status between the electrode and the tissue within the body cavity can be determined. For example, it can be determined whether the electrode is in contact with the wall of the body cavity tissue and the degree of contact. The electrode used to determine whether it is in contact with the tissue within the body cavity is the working electrode.

[0074] Impedance acquisition at different frequencies includes time-division acquisition and frequency-division acquisition.

[0075] The so-called time-division acquisition can be described as follows: When there are several (e.g., n) frequencies for impedance information acquisition, we sequentially acquire the impedance information at the 1st frequency, the 2nd frequency, and so on, up to the nth frequency. After this round of acquisition is completed, or after a certain interval, we start again from the 1st frequency and sequentially acquire the impedance information at the 1st frequency, the 2nd frequency, and so on, up to the nth frequency. This time-division acquisition continues in this manner.

[0076] The following description in this application uses frequency division acquisition as an example.

[0077] The sampling frequency can be selected based on the different degrees to which two or more tissue impedances respond to the frequency. Figure 1 The relative permittivity of blood, blood vessels, and the heart at different frequencies is shown. Figure 2 This displays the conductivity of blood, blood vessels, and the heart at different frequencies. Multiple impedance sampling frequencies can be selected, for example, in the range of 500 Hz to 100 kHz.

[0078] The sampling frequency can be determined based on the actual application scenario. For example, according to... Figure 1 and Figure 2The scenario shown illustrates contact identification between electrodes inside the heart chambers and blood vessels and tissue. Based on the different frequency responses of the myocardium, blood vessel walls, and blood impedance, an appropriate acquisition frequency is selected, following the principle of maximizing the impedance difference among these three components at the chosen frequency. Here, a large difference can be understood as high resolution in tissue differentiation.

[0079] Those skilled in the art should recognize that, Figure 1 and Figure 2 This reflects the principle of different tissue impedances responding differently to frequency. In fact, the two diagrams describe the same principle, only the representation is different: Figure 1 It is described from the perspective of relative permittivity. Figure 2 This is described from the perspective of electrical conductivity.

[0080] Intrusion device

[0081] The intrusion device involved in this invention will now be discussed.

[0082] Invasive devices, also known as body cavity invasive devices, are devices that can penetrate into body cavities.

[0083] In a preferred embodiment of the invention, the invasive device is an invasive catheter. An electrode is disposed at the distal end of the invasive catheter. The object of the invention is to determine whether and to what extent the electrode (e.g., an ablation electrode) on the invasive catheter is in contact with tissue within a body cavity (e.g., the body cavity wall or body cavity surface).

[0084] Figure 3A This is a schematic diagram of a ring-shaped invasive catheter. Figure 3B This is a schematic diagram of the application of a ring-shaped invasive catheter.

[0085] When the invasive catheter is as follows Figure 3A When the annular invasive catheter is shown, the catheter 300 includes an operating handle 301, a proximal end of the catheter 302, a distal end of the catheter 303, a tube body 304, an annular electrode (working electrode) 305, and reference electrodes 306 and 307.

[0086] like Figure 3B As shown, in the context of annular duct invading a body cavity, the tissues or organs that may come into contact with or be adjacent to include: left atrial wall 308, left atrial cavity 309, right superior pulmonary vein 310, right inferior pulmonary vein 311, left inferior pulmonary vein 312, and left superior pulmonary vein 313.

[0087] Figure 4A This is a schematic diagram of a petal-shaped invasive duct. Figure 4B This is a schematic diagram of the application of petal-shaped invasive catheters.

[0088] When the invasive catheter is as follows Figure 4AWhen the petal-shaped invasive catheter is shown, the catheter 400 includes: an operating handle 401, a proximal end of the catheter 402, a distal end of the catheter 403, a petal edge 404, a retractable lever 405, a petal electrode (working electrode) 406, and a lever reference electrode 407.

[0089] like Figure 4B As shown, in the context of a petal-shaped duct invading a body cavity, the tissues or organs that may come into contact with or be adjacent to include: left atrial wall 408, left atrial cavity 409, right superior pulmonary vein 410, right inferior pulmonary vein 411, left inferior pulmonary vein 412, and left superior pulmonary vein 413.

[0090] The design of the invasive catheter ensures that the reference electrode remains in contact with the tissue in most cases during the procedure, thus making it a reasonable reference for determining whether other electrodes (working electrodes) are in contact. Compared to electrode-tissue contact detection methods based on impedance or phase data statistical analysis, this approach offers higher reliability.

[0091] Figure 5 and Figure 6 This demonstrates in more detail the process of determining the contact between the working electrode on the invasive device and the tissue, as well as the displayed results. This will be explained in more detail below.

[0092] Contact recognition method

[0093] The method for electrode-tissue contact identification according to embodiments of the present invention will now be described from a more general perspective.

[0094] Figure 7 This is a flowchart of a method for identifying electrode-tissue contact according to an embodiment of the present invention.

[0095] like Figure 7 As shown, the method 700 for identifying electrode-tissue contact begins at step S710, in which the impedance between electrodes on the body cavity intrusion device is acquired at different frequencies.

[0096] In step S710, the different acquisition frequencies are selected based on the varying degrees to which different tissue impedances respond to frequency. Generally, the frequency range of the different acquisition frequencies is from 500Hz to 100kHz. In a preferred embodiment, the different frequencies refer to two different frequencies.

[0097] The following description uses impedance acquisition at two frequencies as an example. The first impedance is obtained by acquiring impedance at a first frequency, and the second impedance is obtained by acquiring impedance at a second frequency. In practical applications, impedance information at more frequencies can be acquired. Common impedance acquisition processes include time-division acquisition and frequency-division acquisition. The process of time-division acquisition has been described above; the example embodiment of this application uses frequency-division acquisition.

[0098] In a preferred embodiment of the present invention, for Figure 3A The annular catheter shown is used for impedance acquisition. According to the method of the present invention, in step S710, the first frequency impedance and the second frequency impedance between adjacent electrodes 305 on the annular surface are acquired; the first frequency impedance and the second frequency impedance between reference electrodes 306 and 307 are also acquired. Specifically, the catheter design considers the relationship between the spacing between adjacent electrodes 305 and the electrode spacing between reference electrodes 306 and 307, for example, ensuring they are equal or proportional. This relationship can serve as a parameter for subsequent electrode-tissue contact identification. The reference electrodes are not limited to the two reference electrodes described in the patent; more than two reference electrodes can be arranged to establish linear or nonlinear relationships between different reference electrode spacings and impedance.

[0099] In another preferred embodiment of the invention, for Figure 4A The petal-shaped catheter shown is used for impedance acquisition. According to the method of the present invention, in step S710, the first frequency impedance and the second frequency impedance between adjacent electrodes 406 on the annular petal edge 404 are acquired; the first frequency impedance and the second frequency impedance between reference electrodes 407 are also acquired. Specifically, the catheter design considers the relationship between the spacing between adjacent electrodes 406 and the electrode spacing between reference electrodes 407, for example, ensuring they are equal or proportional. This relationship can serve as a parameter for subsequent electrode-tissue contact identification. The reference electrodes are not limited to the two reference electrodes described in the patent; more than two reference electrodes can be arranged on the telescopic rod 405 to establish linear or nonlinear relationships between different reference electrode spacings and impedance.

[0100] Back Figure 7 Next, in step S720, the impedance frequency response coefficient between the electrodes is determined based on the impedance between the electrodes acquired in step S710.

[0101] Then, in Figure 7 In step S730, the contact between the electrode and the tissue inside the body cavity is determined based on the impedance frequency response coefficient.

[0102] In step S730, in a preferred embodiment, it is necessary to determine the working electrode (e.g., Figure 3A The adjacent to the toroidal electrode 305 shown, or Figure 4A The contact between the adjacent electrode 406 on the toroidal petal edge 404 shown and the tissue within the body cavity, rather than the reference electrode (e.g. Figure 3A The reference electrodes 306 and 307 shown, or Figure 4A The contact between the pull rod reference electrode 407 shown and the tissue inside the body cavity.

[0103] The following is through Figure 5 To illustrate how a preferred embodiment of the present invention is carried out Figure 7 The operations of steps S720 and S730.

[0104] Taking the identification of contact between the impedance pair electrode and tissue at two frequencies as an example, the specific process is as follows: Figure 5 As shown.

[0105] Figure 5 This is a flowchart of a method for identifying electrode-tissue contact according to a preferred embodiment of the present invention.

[0106] like Figure 5 As shown, the method 500 for identifying electrode-tissue contact begins at step 502, in which a first frequency impedance and a second frequency impedance between the electrodes are acquired, as described above.

[0107] Then, in step 504, the impedance frequency response coefficient between the working electrodes is calculated. In step 506, the impedance frequency response coefficient between the reference electrodes is calculated. Next, in step 508, the contact index between the electrodes and the tissue is calculated. Finally, in step 510, the output displays whether and to what extent the invasive catheter electrodes are in contact with the tissue.

[0108] More specifically, the desired contact between the working electrode and the tissue can be obtained through the following calculation formula.

[0109] (1) Impedance frequency response coefficient between working electrodes i and j

[0110]

[0111] (2) Impedance frequency response coefficient between reference electrodes m and n

[0112]

[0113] (3) Contact Index (CI) between working electrodes i and j and the tissue

[0114]

[0115] In equations (1), (2), and (3) above, This represents the impedance measured between working electrodes i and j at the first frequency Fr1. This represents the impedance measured between working electrodes i and j at the second frequency Fr2. Let represent the real part of the complex impedance measured between working electrodes i and j at the first frequency Fr1. Let represent the real part of the complex impedance measured between working electrodes i and j at the second frequency Fr2. This represents the imaginary part of the complex impedance measured between working electrodes i and j at the first frequency Fr1. This represents the imaginary part of the complex impedance measured between working electrodes i and j at the second frequency Fr2. This represents the impedance measured between reference electrodes m and n at the first frequency Fr1. This represents the impedance measured between reference electrodes m and n at the second frequency Fr2. Let represent the real part of the complex impedance measured between reference electrodes m and n at the first frequency Fr1. Let represent the real part of the complex impedance measured between reference electrodes m and n at the second frequency Fr2. This represents the imaginary part of the complex impedance measured between reference electrodes m and n at the first frequency Fr1. a represents the imaginary part of the complex impedance measured between reference electrodes m and n at the second frequency Fr2. ij b ij c ij a mn b mn c mn Base is the weighting coefficient. ij Base is the base of the frequency response between working electrodes i and j. mn As the base of the frequency response between reference electrodes m and n, Dis ij Dis is the distance between working electrodes i and j. mn The distance between reference electrodes m and n is denoted as m.

[0116] The Base and Dis parameters are related. That is, the Base parameter... ij Parameters and the Base mn Parameters and the Dis ij Parameters and the Dis mn The parameters are correlated.

[0117] Furthermore, electrode parameters, such as width W and diameter D, are also influencing factors of the Base parameters. Base parameters are catheter-specific parameters. As a known input system, specific Base parameters can be obtained through high-order regression modeling analysis with Dis, W, and D parameters. In other words, the Base... ij Parameters and the Base mn Parameters are obtained through the Dis ij Parameters and the Dis mn The parameters, electrode width parameter, and electrode diameter parameter were obtained through high-order regression modeling analysis.

[0118] Weighting coefficient a ij b ij c ij a mn b mn cmn The magnitude reflects the weights of the impedance, capacitive reactance, and combined RC characteristics of the tissue or blood between electrodes in the application environment, where a ij +b ij +c ij =1, a mn +b mn +c mn =1.

[0119] In step 510, based on the contact index (or adhesion index) CI, the contact between the electrode and the tissue is determined by comparing it with a preset threshold limit; the degree of contact between the electrode and the tissue can also be determined by comparing it with multiple preset threshold limits.

[0120] In addition, the contact between the electrode and the tissues inside the body cavity can be indicated by differences in color.

[0121] Figure 6 This is a schematic diagram showing the display of contact recognition results.

[0122] like Figure 6 As shown, the screen 601 of the display 600 indicates whether the electrode is in contact with the tissue, and the color of the electrode 602 indicates the degree of contact between the electrode and the tissue; the central part 603 displays the current adhesion trend, showing which electrodes are in contact with the tissue. Different prominent colors are used to mark those in contact and those not in contact, and the adhesion index value is also indirectly displayed, reflecting the degree of contact between the electrode and the tissue.

[0123] Contact recognition system

[0124] Figure 8 This is a schematic block diagram of an electrode-tissue contact recognition system according to an embodiment of the present invention.

[0125] like Figure 8 As shown, the electrode-tissue contact identification system 800 includes an acquisition unit 810, an impedance frequency response coefficient determination unit 820, and a contact condition determination unit 830.

[0126] The acquisition unit 810 is used to acquire the impedance between electrodes on the body cavity intrusion device at different frequencies.

[0127] The body cavity invasive device includes a catheter, with the electrode positioned at the distal end of the catheter.

[0128] The duct can be at least one or any one of the following: basket-shaped duct, balloon-shaped duct, coil-shaped duct, petal-shaped duct, grid-shaped duct, and linear duct.

[0129] The electrodes described herein include a working electrode (or, in a therapeutic context, a treatment electrode) and a reference electrode. For example, the working electrode may be an ablation electrode. Therefore, the acquisition unit 810 can be used to acquire impedances between working electrodes, between reference electrodes, and between the working electrode and the reference electrode at different frequencies.

[0130] Different frequencies can be selected based on the varying degrees to which different tissue impedances respond to frequency.

[0131] The frequency range for different frequencies is from 500Hz to 100kHz.

[0132] In a preferred embodiment, the different frequencies are two different frequencies.

[0133] The impedance frequency response coefficient determination unit 820 is used to determine the impedance frequency response coefficient between electrodes based on the impedance between electrodes acquired by the acquisition unit 810.

[0134] The impedance frequency response coefficient determination unit 820 can calculate the impedance frequency response coefficient between the working electrodes and the impedance frequency response coefficient between the reference electrodes according to the above equations (1) and (2).

[0135] The contact condition determination unit 830 is used to determine the contact condition between the electrode and the tissue within the body cavity based on the impedance frequency response coefficient. Specifically, the contact condition determination unit can be used to determine the contact condition between the working electrode and the tissue within the body cavity.

[0136] More specifically, the contact condition determination unit 830 can calculate the contact index CI between the working electrodes i and j and the tissue according to the above formula (3).

[0137] The system 800 may further include a display unit (not shown) for displaying the contact between the electrode and the tissue within the body cavity through color differences.

[0138] Those skilled in the art should understand that the above-mentioned technical means, steps, and units can be arbitrarily combined to achieve the purpose of the present invention, unless they are logically or physically impossible to combine.

[0139] Computer programs, computer-readable media

[0140] Furthermore, those skilled in the art will recognize that the methods of this disclosure can be implemented as computer programs. As described above in conjunction with the accompanying drawings, performing the methods of the above embodiments by one or more programs includes instructions to cause a computer or processor to execute the algorithms described in conjunction with the drawings. These programs can be stored and provided to a computer or processor using various types of non-transitory computer-readable media. Non-transitory computer-readable media include various types of tangible storage media. Examples of non-transitory computer-readable media include magnetic recording media (such as floppy disks, magnetic tapes, and hard disk drives), magneto-optical recording media (such as magneto-optical disks), CD-ROMs (Compact Disc Read-Only Memory), CD-Rs, CD-R / Ws, and semiconductor memories (such as ROMs, PROMs (Programmable ROMs), EPROMs (Erasable and Writable PROMs), flash memory ROMs, and RAMs (Random Access Memory)). Further, these programs can be provided to a computer using various types of transient computer-readable media. Examples of transient computer-readable media include electrical signals, optical signals, and electromagnetic waves. Transient computer-readable media can be used to provide programs to a computer via wired or wireless communication paths such as wires and optical fibers.

[0141] For example, according to one embodiment of this disclosure, an apparatus for identifying electrode-tissue contact can be provided. The apparatus includes a processor and a memory. The memory stores a computer program that, when executed by the processor, implements the electrode-tissue contact identification method as described above.

[0142] Therefore, according to this disclosure, a computer program or a computer-readable medium may also be proposed having instructions stored thereon that are executable by a processor, which, when executed by the processor, cause the processor to perform the electrode-tissue contact identification method as described above.

[0143] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, and the scope of the invention is not limited to the embodiments described above. Many modifications and variations will be apparent to those skilled in the art without departing from the spirit and scope of the invention. That is, those skilled in the art can make various changes and improvements to the invention in form and detail, and all of these are considered to fall within the protection scope of the invention. The terminology used herein is chosen to best explain the principles, practical applications, or improvements to the technology in the market of the various embodiments, or to enable those skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for identifying contact between an electrode and tissue, characterized in that, The method includes: The impedance frequency response coefficient between electrodes is determined based on the impedance between electrodes on the intracavitary intrusion device collected at different frequencies. The electrode includes a working electrode and a reference electrode. The determination of the impedance frequency response coefficient between the electrodes includes: calculating the impedance frequency response coefficient between the working electrodes and the impedance frequency response coefficient between the reference electrodes according to equations (1) and (2), respectively. The impedance frequency response coefficient Coef between working electrodes i and j ij for: The impedance frequency response coefficient Coef between reference electrodes m and n mn for: Based on the impedance frequency response coefficient, the contact condition between the electrode and the tissue within the body cavity is determined; wherein determining the contact condition between the electrode and the tissue within the body cavity includes: calculating the contact index CI between the working electrodes i and j and the tissue according to equation (3): In equations (1), (2), and (3) above, This represents the impedance measured between working electrodes i and j at the first frequency Fr1. This represents the impedance measured between working electrodes i and j at the second frequency Fr2. Let represent the real part of the complex impedance measured between working electrodes i and j at the first frequency Fr1. Let represent the real part of the complex impedance measured between working electrodes i and j at the second frequency Fr2. This represents the imaginary part of the complex impedance measured between working electrodes i and j at the first frequency Fr1. This represents the imaginary part of the complex impedance measured between working electrodes i and j at the second frequency Fr2. This represents the impedance measured between reference electrodes m and n at the first frequency Fr1. This represents the impedance measured between reference electrodes m and n at the second frequency Fr2. Let represent the real part of the complex impedance measured between reference electrodes m and n at the first frequency Fr1. Let represent the real part of the complex impedance measured between reference electrodes m and n at the second frequency Fr2. This represents the imaginary part of the complex impedance measured between reference electrodes m and n at the first frequency Fr1. a represents the imaginary part of the complex impedance measured between reference electrodes m and n at the second frequency Fr2. ij b ij c ij a mn b mn c mn Base is the weighting coefficient. ij Base is the base of the frequency response between working electrodes i and j. mn As the base of the frequency response between reference electrodes m and n, Dis ij Dis is the distance between working electrodes i and j. mn The distance between reference electrodes m and n is denoted as m.

2. The method according to claim 1, characterized in that, The working electrode includes an ablation electrode.

3. The method according to claim 1, characterized in that, The determination of the contact between the electrode and the tissue within the body cavity includes: determining the contact between the working electrode and the tissue within the body cavity.

4. The method according to claim 1, characterized in that, The body cavity intrusion device includes a catheter, and the electrode is disposed at the distal end of the catheter.

5. The method according to claim 4, characterized in that, The catheter includes at least one of the following: basket-shaped catheter, balloon-shaped catheter, coil-shaped catheter, petal-shaped catheter, grid-shaped catheter, and linear catheter.

6. The method according to claim 1, characterized in that, The different frequencies are selected based on the varying degrees to which different tissue impedances respond to frequency.

7. The method according to claim 1, characterized in that, The frequency range of the different frequencies is from 500Hz to 100kHz.

8. The method according to claim 1, characterized in that, The different frequencies are two different frequencies.

9. The method according to claim 1, characterized in that, The Base ij Parameters and the Base mn Parameters and the Dis ij Parameters and the Dis mn The parameters are correlated.

10. The method according to claim 9, characterized in that, The Base ij Parameters and the Base mn Parameters are obtained through the Dis ij Parameters and the Dis mn The parameters, electrode width parameter, and electrode diameter parameter were obtained through high-order regression modeling analysis.

11. The method according to claim 1, characterized in that, Weighting coefficient a ij b ij c ij a mn b mn c mn The magnitude reflects the weights of the impedance, capacitive reactance, and combined RC characteristics of the tissue or blood between electrodes in the application environment, where a ij +b ij +c ij =1, a mn +b mn +c mn =1.

12. The method according to claim 1, characterized in that, The method further includes: displaying the contact between the electrode and the tissue within the body cavity through color differences.

13. A system for identifying contact between electrodes and tissue, characterized in that, The system includes: The acquisition unit is used to acquire the impedance between electrodes on the intracavitary invasive device at different frequencies. The impedance frequency response coefficient determination unit is used to determine the impedance frequency response coefficient between electrodes based on the collected impedance between electrodes. The electrode includes a working electrode and a reference electrode. The impedance frequency response coefficient determination unit is configured to calculate the impedance frequency response coefficients between the working electrodes and between the reference electrodes according to equations (1) and (2), respectively. The impedance frequency response coefficient Coef between working electrodes i and j ij for: The impedance frequency response coefficient Coef between reference electrodes m and n mn for: A contact condition determination unit is used to determine the contact condition between the electrode and the tissue within the body cavity based on the impedance frequency response coefficient; wherein, the contact condition determination unit is configured to: calculate the contact index CI between the working electrodes i and j and the tissue according to equation (3): In equations (1), (2), and (3) above, This represents the impedance measured between working electrodes i and j at the first frequency Fr1. This represents the impedance measured between working electrodes i and j at the second frequency Fr2. Let represent the real part of the complex impedance measured between working electrodes i and j at the first frequency Fr1. Let represent the real part of the complex impedance measured between working electrodes i and j at the second frequency Fr2. This represents the imaginary part of the complex impedance measured between working electrodes i and j at the first frequency Fr1. This represents the imaginary part of the complex impedance measured between working electrodes i and j at the second frequency Fr2. This represents the impedance measured between reference electrodes m and n at the first frequency Fr1. This represents the impedance measured between reference electrodes m and n at the second frequency Fr2. Let represent the real part of the complex impedance measured between reference electrodes m and n at the first frequency Fr1. Let represent the real part of the complex impedance measured between reference electrodes m and n at the second frequency Fr2. This represents the imaginary part of the complex impedance measured between reference electrodes m and n at the first frequency Fr1. a represents the imaginary part of the complex impedance measured between reference electrodes m and n at the second frequency Fr2. ij b ij c ij a mn b mn c mn Base is the weighting coefficient. ij Base is the base of the frequency response between working electrodes i and j. mn As the base of the frequency response between reference electrodes m and n, Dis ij Dis is the distance between working electrodes i and j. mn The distance between reference electrodes m and n is denoted as m.

14. The system according to claim 13, characterized in that, The working electrode includes an ablation electrode.

15. The system according to claim 13, characterized in that, The contact condition determination unit is configured to determine the contact condition between the working electrode and the tissue within the body cavity.

16. The system according to claim 13, characterized in that, The body cavity intrusion device includes a catheter, and the electrode is disposed at the distal end of the catheter.

17. The system according to claim 16, characterized in that, The catheter includes at least one of the following: basket-shaped catheter, balloon-shaped catheter, coil-shaped catheter, petal-shaped catheter, grid-shaped catheter, and linear catheter.

18. The system according to claim 13, characterized in that, The different frequencies are selected based on the varying degrees to which different tissue impedances respond to frequency.

19. The system according to claim 13, characterized in that, The frequency range of the different frequencies is from 500Hz to 100kHz.

20. The system according to claim 13, characterized in that, The different frequencies are two different frequencies.

21. The system according to claim 13, characterized in that, The Base ij Parameters and the Base mn Parameters and the Dis ij Parameters and the Dis mn The parameters are correlated.

22. The system according to claim 21, characterized in that, The Base ij Parameters and the Base mn Parameters are obtained through the Dis ij Parameters and the Dis mn The parameters, electrode width parameter, and electrode diameter parameter were obtained through high-order regression modeling analysis.

23. The system according to claim 13, characterized in that, Weighting coefficient a ij b ij c ij a mn b mn c mn The magnitude reflects the weights of the impedance, capacitive reactance, and combined RC characteristics of the tissue or blood between electrodes in the application environment, where a ij +b ij +c ij =1, a mn +b mn +c mn =1.

24. The system according to claim 13, characterized in that, The system further includes a display unit for displaying the contact status between the electrodes and tissues within the body cavity through color differences.

25. A computer-readable medium having stored thereon instructions executable by a processor, said instructions, when executed by the processor, causing the processor to perform the method for identifying electrode-tissue contact as described in claim 1.

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