An anti-arc ablation catheter with a conductive coating

Abstract

The present invention relates to the technical field of medical devices, and specifically relates to an anti-arc ablation catheter with a conductive coating. An anti-arc ablation catheter with a conductive coating includes a handle, a catheter body, and a tube body. It is characterized in that: the handle is connected to the catheter body through the tube body. The catheter body includes an insulating layer and an electrode layer, and a plurality of electrode layers are sleeved outside the insulating layer. Compared with the prior art, the present invention provides an anti-arc ablation catheter with a conductive coating. The conductive coating is applied to the edge of the catheter electrode, aiming to change the local conduction condition at the edge of the catheter electrode, reduce the current density at the electrode edge, and reduce the attachment of bubbles so as to prevent the generation of arcs.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and more particularly to an anti-arc ablation catheter with a conductive coating. Background Art

[0002] Atrial fibrillation (AF) is one of the most common arrhythmias, which is an atrial rhythm with disordered excitation and ineffective contraction. When it occurs, the atrium loses its normal and effective contraction function and is in a rapid and disordered fibrillation state. Research shows that catheter ablation is an effective means for patients with atrial fibrillation to restore and maintain sinus rhythm.

[0003] Pulsed Field Ablation (PFA) uses high-voltage pulsed electric fields to act on the tissue in the heart cavity. The phospholipid bilayer of the cell membrane moves and rearranges under the action of the pulsed electric field to form irreversible electroporation, thereby causing apoptosis and death of the cells. With the continuous application of the pulse train, the tissue dies in patches, thereby achieving the purpose of eliminating and preventing the transmission of abnormal potentials that cause arrhythmias.

[0004] The arc discharge phenomenon generated between the catheter electrodes under high voltage is one of the potential side effects during pulsed field ablation. The occurrence of the arc is related to the local ultra-high electric field or ultra-high current density formed at the electrode edge during pulsed discharge. There are many ways to avoid the occurrence of the arc. For example, as mentioned in US Patent No. 2019 / 0307500A1, a variable resistor in series with the patient's body impedance is added to the pulse output device of the pulsed ablation system to limit the output current, so as to avoid too high local current at the edge of the catheter electrode, that is, to reduce the probability of arc occurrence. However, adding a series resistor will cause a part of the voltage of the pulsed power supply to be divided away, reducing the output voltage at the catheter electrode end, that is, it may reduce the ablation damage range.

[0005] The fundamental cause of arc generation is that the gas in the blood is broken down by the electric field. During pulsed field ablation, it may cause too high local current density at the edge of the catheter circular electrode, as Figure 5 、 Figure 6 shown. The high current density at the edge of the metal electrode will cause rapid electrolysis of the solution and generate a large number of microbubbles. These microbubbles gather at the electrode edge under the action of surface tension to form bubble aggregation and occupy and wrap the electrode surface, thereby reducing the effective area of the circular electrode and lowering the arc generation threshold. With the cumulative application of the pulse group, when the bubble coverage is formed and the next group of pulses is applied, the applied high voltage will cause these attached gases to be broken down by the electric field to form an arc discharge phenomenon. Therefore, changing the electric field distribution at the edge of the catheter electrode through catheter design changes is the fundamental and more reasonable solution to solve the arc. Summary of the Invention

[0006] In order to overcome the deficiencies of the prior art, the present invention provides an anti-arc ablation catheter with a conductive coating. The conductive coating is applied to the edge of the catheter electrode, aiming to change the local conductive condition at the edge of the catheter electrode, reduce the current density at the electrode edge, and reduce the attachment of bubbles so as to prevent the generation of arcs.

[0007] To achieve the above object, an anti-arc ablation catheter with a conductive coating is designed, which includes a handle, a catheter body, and a tube body. It is characterized in that: the handle is connected to the catheter body through the tube body, and the catheter body includes an insulating layer and an electrode layer, and several electrode layers are sleeved outside the insulating layer.

[0008] The insulating layer has a straight catheter or annular catheter structure, the electrode layer is coated on the outer edge of the insulating layer, and a conductive coating is provided between the electrode layer and the insulating layer.

[0009] The catheter body has an annular, straight, basket or balloon morphological structure.

[0010] The raw material composition of the conductive coating includes: 1-30 parts by weight of a conductive component, 10-30 parts by weight of a matrix resin, 50-200 parts by weight of a solvent, and 0.1-10 parts by weight of an additive.

[0011] The conductive component is one or a mixture of metal powders and ionic compound powders, and the particle size of the powders is 1 nm - 1000 nm.

[0012] The metal powders are gold metal powder, silver metal powder, platinum metal powder; the ionic compound powders are sodium chloride powder, polyacrylic acid powder.

[0013] The matrix resin is one or a mixture of polyurethane, epoxy resin, and polycyanoacrylate.

[0014] The solvent is any one or a mixture of N-methylpyrrolidone, N,N'-dimethylformamide, acetone, butanone, cyclohexanone, butyl acetate, ethyl acetate, ethanol, ethylene glycol, n-propanol, isopropanol, n-butanol, 1,4-butanediol, isooctanol.

[0015] The described additives include a dispersant, a leveling agent, an antifoaming agent, and a crosslinking agent. The dispersant is one or a mixture of several of polyvinyl alcohol, polyethylene glycol, and polyvinylpyrrolidone polymer-type dispersants; the leveling agent is any one of silicone leveling agents, acrylic leveling agents, and fluorocarbon leveling agents; the antifoaming agent is any one of polymer antifoaming agents and silicone antifoaming agents; the crosslinking agent is a polyisocyanate, such as any one of toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), dicyclohexylmethane diisocyanate (HMDI), hexamethylene diisocyanate (HDI), and lysine diisocyanate (LDI).

[0016] The preparation process of the conductive coating is as follows:

[0017] (1) Weigh the following components in parts by weight respectively: 1 - 30 parts of conductive component, 10 - 30 parts of matrix resin, 50 - 200 parts of solvent, and 0.1 - 10 parts of additive;

[0018] (2) Dissolve the matrix resin in the solvent and stir until completely dissolved to obtain a matrix resin solution; Take the conductive component, dispersant, leveling agent, and antifoaming agent and place them in the matrix resin solution, and perform sufficient dispersion through ultrasonic and mechanical stirring to obtain a matrix resin mixed solution;

[0019] (3) Place the crosslinking agent in the matrix resin mixed solution and stir thoroughly until completely dissolved to obtain a conductive coating solution;

[0020] (4) Coat the prepared conductive coating solution around the electrode layer or at the outer edge position of the electrode layer, and dry it into a film through photocuring or thermal curing.

[0021] Compared with the prior art, the present invention provides an anti-arc ablation catheter with a conductive coating. The conductive coating is applied to the edge of the catheter electrode, aiming to change the local conductive condition at the edge of the catheter electrode, reduce the current density at the electrode edge, and reduce the attachment of bubbles, thereby preventing the generation of arcs. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic structural diagram of the present invention.

[0023] Figure 2 It is a schematic structural diagram of the catheter body.

[0024] Figure 3 It is a cross-sectional view of the catheter body structure.

[0025] Figure 4 It is a schematic structural diagram of a straight catheter.

[0026] Figure 5 、 Figure 6Application scenarios of traditional catheter and schematic diagram of arc discharge

[0027] Figure 7 、 Figure 8 Application scenarios of catheter body in Embodiment 1 and schematic diagram of arc discharge

[0028] Figure 9 、 Figure 10 Application scenarios of catheter body in Embodiment 2 and schematic diagram of arc discharge Detailed implementation manners

[0029] The present invention will be further described below with reference to the accompanying drawings.

[0030] As Figure 1 , Figure 2 shown, the handle 3 is connected to the catheter body 1 through the tube body 2. The catheter body 1 includes an insulating layer and an electrode layer. A plurality of electrode layers 1-1 are sleeved outside the insulating layer 1-2.

[0031] As Figure 3 shown, the insulating layer 1-2 has a straight catheter or annular catheter structure. The electrode layer 1-1 is coated on the outer edge of the insulating layer 1-2. A conductive coating 1-3 is provided between the electrode layer 1-1 and the insulating layer 1-2.

[0032] A plurality of electrode layers 1-1 are sleeved on the insulating layer 1-2. The number of electrode layers 1-1 and the distance between two adjacent electrode layers 1-1 can be adjusted as needed.

[0033] The catheter body 1 has an annular, straight, basket or balloon morphological structure.

[0034] As Figure 4 shown, the catheter body 1 has a straight tubular structure. A plurality of electrode layers are coated on the insulating layer of the straight tubular structure at intervals, and the end electrode layer at the head of the insulating layer is a coated sleeve structure that directly coats the head of the insulating layer.

[0035] The raw material composition of the conductive coating 1-4 includes: 1-30 parts by weight of a conductive component, 10-30 parts by weight of a matrix resin, 50-200 parts by weight of a solvent, and 0.1-10 parts by weight of an additive.

[0036] The conductive component is one or a mixture of metal powder and ionic compound powder, and the particle size of the powder is 1 nm - 1000 nm.

[0037] The metal powder is gold metal powder, silver metal powder, platinum metal powder; the ionic compound powder is sodium chloride powder, polyacrylic acid powder.

[0038] The matrix resin is one or a mixture of polyurethane, epoxy resin, and polycyanoacrylate.

[0039] The solvent is any one of N-methylpyrrolidone, N,N'-dimethylformamide, acetone, butanone, cyclohexanone, butyl acetate, ethyl acetate, ethanol, ethylene glycol, n-propanol, isopropanol, n-butanol, 1,4-butanediol, and isooctyl alcohol, or a mixture of several of them.

[0040] The additives include dispersants, leveling agents, defoamers, and crosslinking agents. The dispersant is one or a mixture of polyvinyl alcohol, polyethylene glycol, and polyvinyl pyrrolidone polymer dispersants; the leveling agent is any one of an organic silicon leveling agent, an acrylic leveling agent, and a fluorocarbon leveling agent; the defoamer is any one of a polymer defoamer and an organic silicon defoamer; the crosslinking agent is a polyisocyanate, such as any one of toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), dicyclohexylmethane diisocyanate (HMDI), hexamethylene diisocyanate (HDI), and lysine diisocyanate (LDI).

[0041] Traditionally, the fundamental cause of arc generation is that the gas in the blood is broken down by the electric field. During pulsed electric field ablation, the local current density at the edge of the catheter ring electrode may be too high, such as Figure 5 , Figure 6 As shown. The high current density at the edge of the metal electrode will cause the solution to electrolyze quickly and generate a large number of microbubbles. These microbubbles gather at the edge of the electrode under the action of surface tension to form bubble aggregation and occupy the surface of the wrapped electrode, thereby reducing the effective area of ​​the ring electrode and lowering the threshold for arc occurrence. With the cumulative application of the pulse group, when the bubble coverage is formed when the next group of pulses is applied, the applied high voltage will cause these attached gases to be broken down by the electric field to form an arc discharge phenomenon.

[0042] The preparation process of the conductive coating is as follows:

[0043] (1) Weigh the following components in parts by weight: 1-30 parts of conductive component, 10-30 parts of base resin, 50-200 parts of solvent and 0.1-10 parts of auxiliary agent;

[0044] (2) dissolving the matrix resin in a solvent and stirring until it is completely dissolved to obtain a matrix resin solution; placing a conductive component, a dispersant, a leveling agent, and a defoaming agent in the matrix resin solution, and fully dispersing them by ultrasonic and mechanical stirring to obtain a matrix resin mixed solution;

[0045] (3) placing the crosslinking agent in the matrix resin mixed solution and stirring thoroughly until it is completely dissolved to obtain a conductive coating solution;

[0046] (4) Coat the prepared conductive coating solution around the electrode layer or at the outer edge position of the electrode layer, and dry it into a film by photocuring or thermal curing.

[0047] Further, after grinding the edge of the catheter annular electrode into a rounded corner, coating can be carried out. However, the aforementioned electrode edge treatment is not necessary. The coating position can be the outer wall of the electrode or the outer wall of the insulating polymer between the electrodes.

[0048] Example 1:

[0049] An example of the present invention is as Figure 1 , Figure 2 shown, including a handle 3: for adjusting the bending degree of the head end and electrical connection; a tube body 2: located between the handle 3 and the electrode head end of the catheter body 1, aiming to transport the electrode to the treatment site; a catheter body 1: for ablating by adhering to the tissue; wherein the electrodes of the catheter body 1 include several electrode layers 1-1, and the electrode layers 1-1 are coated on the outside of the insulating layer 1-2, and a conductive coating 1-3 is coated between the electrode layers 1-1 and the insulating layer 1-2. The application scenario of this embodiment is as Figure 7 shown, that is, the head end electrode of the catheter body 1 is placed in the heart, the upper part of the catheter body 1 is located in the blood 4, and the lower end face of the catheter body 1 adheres to the myocardial tissue 5 for ablation.

[0050] The front-end structure of this embodiment is as Figure 7 shown. After the electrode layer 1-1 is rounded, a conductive coating 1-3 is coated between the electrode layer 1-1 and the insulating layer 1-2. The conductivity range of the conductive coating 1-3 is between 0.01 s / m and 10 s / m, preferably 0.1 s / m - 1 s / m, and more preferably in the range of 0.2 s / m - 0.6 s / m (0.2 s / m is the conductivity of the myocardium, and 0.6 s / m is the conductivity of the blood). The coating thickness can be in the range of 0.1 - 100 um, preferably in the range of 1-20 um. The edge curvature of the coated rounded electrode is represented by the Figure 3 curvature, and the range of the radius of curvature can be 10-100 um, preferably 25-100 um (the single-side thickness of the catheter annular electrode is usually 50 um - 200 um, and it is relatively easy to grind half of the thickness into a rounded corner / oblique angle in the process). The span of the rounded corner can be between 0-90 degrees, preferably between 45-90 degrees.

[0051] Example 2:

[0052] Another example of the present invention is as Figure 9 shown. In this embodiment, a conductive coating 1-3 is coated at the junction of the edge of the electrode layer 1-1 and the insulating layer, or on the outer surface of the electrode layer 1-1. As Figure 10As shown, the coating can also effectively reduce the local electric field strength at the electrode edge (the coating height is 25 um, the conductivity is 0.3 s / m, the applied voltage is 1400 V, and the distance between the two electrodes is 2 mm). The conductivity range of the conductive coatings 1-3 is between 0.01 s / m and 10 s / m, preferably 0.1 s / m - 1 s / m, and more preferably in the range of 0.2 s / m - 0.6 s / m (0.2 s / m is the electrical conductivity of the myocardium, and 0.6 s / m is the electrical conductivity of the blood). The specific coating thickness can be in the range of 0.1 - 100 um, preferably in the range of 1 - 20 um. The edge curvature of the coated rounded electrode is represented by Figure 3 the curvature in

[0053] The radius of curvature ranges from 10 - 100 um, preferably 25 - 100 um. The span of the rounded corner is between 0 - 90 degrees, preferably between 45 - 90 degrees.

[0054] According to requirements, the structure of the catheter body 1 can be one of a straight catheter, a ring catheter, a basket catheter, and a balloon catheter, and the conductive coatings 1-3 can also be coated on the end electrode of the straight catheter or on the electrode layer 1-1 behind the end electrode. Adding a conductive coating on the surface, edge, or between the electrodes of the catheter electrode will reduce the ultra-high electric field strength formed at the edge of the traditional circular electrode, thereby preventing the generation of electric arcs.

Claims

1. An anti-arc ablation catheter with a conductive coating, comprising a handle, a catheter body, and a tube body, Characterized in that: The handle (3) is connected to the catheter body (1) through the tube body (2). The catheter body (1) includes an insulating layer and an electrode layer. A plurality of electrode layers (1-1) are sleeved outside the insulating layer (1-2); The insulating layer (1-2) is in a straight catheter or annular catheter structure. The electrode layer (1-1) is coated on the outer edge of the insulating layer (1-2). A conductive coating (1-3) is provided between the electrode layer (1-1) and the insulating layer (1-2), and the conductive coating (1-3) is coated on the edge of the electrode layer (1-1); The raw material composition of the conductive coating (1-3) includes: 1-30 parts by weight of a conductive component, 10-30 parts by weight of a matrix resin, 50-200 parts by weight of a solvent, and 0.1-10 parts by weight of an auxiliary agent.

2. An anti-arc ablation catheter with a conductive coating according to claim 1, Characterized in that: The catheter body (1) is in an annular, straight, basket, or balloon morphological structure.

3. An anti-arc ablation catheter with a conductive coating according to claim 1, Characterized in that: The conductive component is one or a mixture of metal powders and ionic compound powders, and the particle size of the powders is 1 nm - 1000 nm.

4. An anti-arc ablation catheter with a conductive coating according to claim 3, Characterized in that: The metal powder is gold metal powder, silver metal powder, platinum metal powder; the ionic compound powder is sodium chloride powder, polyacrylic acid powder.

5. An anti-arc ablation catheter with a conductive coating according to claim 1, Characterized in that: The matrix resin is one or a mixture of polyurethane, epoxy resin, and polycyanoacrylate.

6. An anti-arc ablation catheter with a conductive coating according to claim 1, Characterized in that: The solvent is any one or a mixture of N-methylpyrrolidone, N,N'-dimethylformamide, acetone, butanone, cyclohexanone, butyl acetate, ethyl acetate, ethanol, ethylene glycol, n-propanol, isopropanol, n-butanol, 1,4-butanediol, and isooctanol.

7. An anti-arc ablation catheter with a conductive coating according to claim 1, Characterized in that: The auxiliary agent includes a dispersant, a leveling agent, an antifoaming agent, and a crosslinking agent. The dispersant is one or a mixture of polyvinyl alcohol, polyethylene glycol, and polyvinylpyrrolidone polymer type dispersants; the leveling agent is any one of silicone leveling agents, acrylic leveling agents, and fluorocarbon leveling agents; the antifoaming agent is any one of polymer antifoaming agents and silicone antifoaming agents; the crosslinking agent is any one of toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), dicyclohexylmethane diisocyanate (HMDI), hexamethylene diisocyanate (HDI), and lysine diisocyanate (LDI).

8. A kind of anti-arc ablation catheter with a conductive coating according to claim 1, characterized in that: The preparation process of the conductive coating (1-3) is as follows: (1) Weigh the following components by weight: 1-30 parts of conductive component, 10-30 parts of matrix resin, 50-200 parts of solvent, and 0.1-10 parts of additive; (2) Dissolve the matrix resin in the solvent and stir until completely dissolved to obtain a matrix resin solution; put the conductive component, dispersant, leveling agent, and defoaming agent into the matrix resin solution, and perform sufficient dispersion through ultrasonic and mechanical stirring to obtain a matrix resin mixed solution; (3) Put the cross-linking agent into the matrix resin mixed solution and stir well until completely dissolved to obtain a conductive coating solution; (4) Coat the prepared conductive coating solution around the electrode layer or at the outer edge position of the electrode layer, and dry it into a film by photocuring or thermal curing.

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