A method of forming a braid, a mapping catheter, and an ablation catheter

Abstract

The application belongs to the technical field of medical devices, and discloses a braided member forming method, a mapping catheter and an ablation catheter. The braided member forming method comprises the following steps: cold-drawing treatment is performed on a nickel-titanium alloy wire to obtain a cold-drawn nickel-titanium alloy wire; an insulating coating is applied to the surface of the cold-drawn nickel-titanium alloy wire; the nickel-titanium alloy wire with the insulating coating is braided on a mold and heat-set to obtain a target braided member; and the insulating coating is removed at a plurality of preset positions of the braided member to expose the nickel-titanium alloy wires at the corresponding positions to form a plurality of electrodes. The cold-drawn nickel-titanium alloy is braided and heat-set, the heat-setting temperature can be reduced, the insulating coating can be prevented from thermal decomposition during heat setting, the shape stability and the insulating performance of the braided member can be simultaneously considered, and the material can maintain the insulating property and the structural integrity during the setting process.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and more particularly to a method for forming a braided component, a mapping catheter, and an ablation catheter. Background Technology

[0002] In recent years, the number of patients with arrhythmias has been increasing year by year. Compared with drug treatment, catheter ablation has a lower recurrence rate and can effectively improve quality of life, and has been widely used in the treatment of arrhythmias. Cardiac catheterization therapy requires first inserting a mapping catheter into a specific location within the heart chamber, recording and analyzing the electrical phenomena and properties of the organism to construct a three-dimensional model of the heart, and then developing a personalized treatment strategy based on these phenomena. Current technology commonly uses high-density mapping catheters for intracardiac signal mapping.

[0003] High-density mapping refers to a mapping technique that involves collecting and analyzing over 300 points within a single cardiac chamber via catheter during three-dimensional mapping to elucidate the mechanisms of arrhythmia. By accurately locating key conduction areas through high-density sampling within the cardiac chamber, a clearer understanding of the arrhythmia matrix can be achieved, thus precisely guiding ablation. Braided catheters are commonly used high-density mapping catheters. They typically have a slender catheter body and a braided section installed at the distal end of the catheter body, which enables high-density electrical signal mapping within the cardiac chamber. The braided section is often made of nickel-titanium alloy wire and has an insulating coating applied to specific areas to achieve electrical isolation.

[0004] The conventional heat-setting temperature range for nickel-titanium alloy wires is 450℃ to 550℃. However, the heat resistance limit of most polymer insulating coatings is significantly lower than this temperature range, leading to easy thermal decomposition of the coating during heat setting. This makes it difficult for existing technologies to simultaneously achieve morphological stability and insulation performance of the braided component: if the heat-setting temperature is lowered during forming, the nickel-titanium wire cannot obtain stable morphological memory; if a high-temperature resistant but poorly insulating coating is used, insulation performance will be sacrificed, affecting the quality of electrical signal acquisition; it is difficult to achieve the dual requirements of morphological stability and insulation performance. If an insulating coating is added after the braided component has been heat-set, it cannot be ensured that the overlapping area of ​​the two nickel-titanium alloy wires is completely covered by the insulating coating, affecting the insulation performance. Summary of the Invention

[0005] The purpose of this application is to provide a method for forming braided parts, a marking catheter, and an ablation catheter, which can simultaneously ensure the morphological stability and insulation performance of the braided parts, and ensure that the material maintains insulation and structural integrity during the shaping process.

[0006] The technical solution provided in this application is as follows: On the one hand, a method for forming a woven part is provided, including the following steps: Cold drawing is performed on nickel-titanium alloy wire to obtain cold-drawn nickel-titanium alloy wire; An insulating coating is applied to the surface of the cold-drawn nickel-titanium alloy wire; The nickel-titanium alloy wire with an insulating coating is woven on a mold and then heat-set to obtain the target woven part; The insulating coating is removed at multiple predetermined locations on the braid to expose the nickel-titanium alloy filaments at the corresponding locations to form multiple electrodes.

[0007] In some embodiments, the cumulative deformation of the cold-drawing treatment of the nickel-titanium alloy wire It ranges from 20% to 70%; in, ; A0 is the cross-sectional area of ​​the nickel-titanium alloy wire before cold drawing; A1 is the cross-sectional area of ​​the cold-drawn nickel-titanium alloy wire.

[0008] In some embodiments, the insulating coating is a polyimide coating.

[0009] In some embodiments, the heat setting is a single heat setting or multiple heat setting, and the temperature of each heat setting is 350°C to 400°C, and the time of each heat setting is 12 to 25 minutes.

[0010] In some embodiments, when the heat setting is a single heat setting, the step of weaving the nickel-titanium alloy wire with an insulating coating on a mold to form a braided part and then performing heat setting to obtain the target braided part specifically includes: Nickel-titanium alloy wire with an insulating coating is woven on a mold of the target shape and then heat-set once to obtain the target woven part.

[0011] In some embodiments, when the heat setting is a multiple heat setting process, the step of weaving the nickel-titanium alloy wire with an insulating coating on a mold and then heat setting it to obtain the target woven part specifically includes: Nickel-titanium alloy wire with an insulating coating is woven on the first mold and subjected to the first heat setting to obtain the first shaped woven part. The first shaped woven part is fixed on the target shaped mold for a second heat setting to obtain the target woven part.

[0012] In some embodiments, the temperature of the first heat setting is 345-355°C, and the heat setting time is 12-20 minutes; The second heat setting temperature is 370-390℃, and the heat setting time is 12-20 minutes.

[0013] In some embodiments, when the heat setting is a multiple heat setting process, the step of weaving the nickel-titanium alloy wire with an insulating coating on a mold and then heat setting it to obtain the target woven part specifically includes: Nickel-titanium alloy wire with an insulating coating is woven on the first mold and subjected to the first heat setting to obtain the first shaped woven part. The first shaped woven piece is sequentially fixed onto one or more second molds for a second heat setting to obtain the second shaped woven piece; The second-shaped woven part is fixed on the target-shaped mold for a third heat setting to obtain the target woven part.

[0014] In some embodiments, the temperature of the first heat setting is 345-355°C, and the heat setting time is 12-20 minutes; The second heat setting temperature is 355-365℃, and the heat setting time is 12-20 minutes; The temperature for the third heat setting is 370-390℃, and the heat setting time is 12-20 minutes.

[0015] In some embodiments, during the multiple heat setting, the temperature of the later heat setting is higher than the temperature of the previous heat setting.

[0016] In some embodiments, the plurality of preset positions are respectively filament segments in the braided mesh, and the electrodes are insulated from each other by the insulating coating.

[0017] In some embodiments, after removing the insulating coating at multiple predetermined locations on the braid to expose the nickel-titanium alloy wires at the corresponding locations to form multiple electrodes, the method further includes: The exposed nickel-titanium alloy wire is surface treated.

[0018] On the other hand, a mapping catheter is also provided, including a catheter body and a braided component installed at the distal end of the catheter body, the braided component being manufactured by the braided component forming method described in any of the above embodiments.

[0019] In another aspect, an ablation catheter is also provided, comprising a catheter body and a braided component installed at the distal end of the catheter body, the braided component being manufactured by the braided component forming method described in any of the above embodiments.

[0020] The technical advantages of this application are as follows: the high-density dislocations and residual stress introduced by the cold-drawing deformation provide additional thermodynamic driving force, significantly reducing the heat-setting temperature of the nickel-titanium alloy wire, for example, from the usual 500°C to below 400°C, thereby matching the temperature resistance limit of the insulating coating and preventing thermal decomposition of the coating. This ensures that the insulating coating maintains its complete and dense electrical isolation performance after heat setting. Furthermore, only the coating needs to be locally scraped off at the predetermined electrode location to expose the conductive area, while the remaining portion remains reliably insulated, eliminating the need for complex masks or multi-step processing. In contrast, traditional high-temperature processes (500°C) can damage the coating, leading to inaccurate control of the insulation boundary or requiring additional complex processes such as secondary coating and laser finishing. The improved braid forming process in this application is not only simple and low-cost, but also ensures the electrical safety of the intracardiac mapping catheter during multi-electrode, high-density mapping, avoiding leakage or signal crosstalk. In addition, the insulating coating can act as an anti-oxidation protective layer during the heat setting process, preventing oxidation of the nickel-titanium alloy wire surface, thus eliminating the need to treat the entire surface of the braid, reducing processing costs and process complexity. Attached Figure Description

[0021] The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments: Figure 1 This is a partial structural schematic diagram of a catheter provided in one embodiment of this application; Figure 2 This is a schematic cross-sectional view of a coated wire provided in an embodiment of this application; Figure 3 This is a schematic diagram of the mesh structure of a woven component provided in one embodiment of this application; Figure 4 This is a schematic diagram of the structure of the coated wire electrode provided in one embodiment of this application; Figure 5 This is a schematic diagram of a catheter used for intracardiac mapping according to an embodiment of this application; Figure 6 This is a schematic flowchart of a method for forming a woven part according to an embodiment of this application; Figure 7 This is a schematic diagram of the structure of the coated wire on the heat-setting mold; Figure 8 This is a schematic diagram of the structure of a cold-drawn nickel-titanium alloy wire after heat treatment at 360℃ for 15 minutes. Figure 9 This is a schematic diagram of the structure of a conventionally annealed nickel-titanium alloy wire after heat treatment at 360°C for 15 minutes. Figure 10 This is a schematic diagram of the structure of a conventionally annealed nickel-titanium alloy wire after heat treatment at 500℃ for 15 minutes. Figure 11This is a schematic diagram of the appearance of the coated wire after heat treatment at 360℃ for 15 minutes. Figure 12 This is a schematic diagram of the appearance of the coated wire after heat treatment at 500℃ for 15 minutes. Figure 13 This is a schematic diagram of the test principle for testing the insulation performance of coated wires after heat treatment; Figure 14 This is a schematic diagram of the structure of a catheter provided in one embodiment of this application.

[0022] Explanation of icon numbers: 110. Catheter body; 120. Braided component; 121. Coated filament; 1211. Nickel-titanium alloy wire; 1212. Insulating coating; 122. Electrode; 130. Connector; 140. Core rod; 200. Far-field electrode; 10. Physiological saline solution; 20. Multimeter. Detailed Implementation

[0023] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application can also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the specific implementation methods of this application will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without creative effort.

[0025] To keep the drawings concise, each drawing only schematically shows the parts relevant to this application, and they do not represent the actual structure of the product. Furthermore, for ease of understanding, in some drawings, only one of the components with the same structure or function is schematically shown, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one."

[0026] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations, for example, “a and / or b” includes: “a alone”, “b alone”, or “a and b”.

[0027] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections via an intermediate medium; or internal connections between two components. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances. The term "relative arrangement" includes parallel relative positions or relative positions at a certain angle, without limitation on the angle.

[0028] In the embodiments shown in the accompanying drawings, the directional indications (such as up, down, left, right, front, and back) are relative rather than absolute when describing the structure and movement of the various components, and are not intended to limit the direction of the product during actual use.

[0029] Furthermore, in the description of this application, ordinal numbers, such as "first" and "second," are used only to distinguish and describe related objects, and should not be construed as indicating or implying the relative importance or order between related objects; in addition, they do not represent the number of related objects.

[0030] In the embodiments of this application, "proximal end" refers to the end of the associated object closer to the operator; "distal end" refers to the end of the associated object farther from the operator. "Proximal end" and "distal end" are the position or orientation of the associated object (e.g., a component of a medical device) relative to the operator (e.g., a doctor) from the perspective of the operator using the device (e.g., a medical device). For example, "proximal end" refers to the end closer to the doctor during normal operation of the medical device, while "distal end" refers to the end farther from the doctor during normal operation of the medical device, that is, the end that first enters the patient's body.

[0031] like Figure 1 As shown, the woven component 120 is woven from dozens to hundreds of coated filaments 121 and heat-set to form a mesh structure. For example... Figure 2 As shown, the coated wire 121 is a nickel-titanium alloy wire 1211 with an insulating coating 1212. That is, the outer surface of the nickel-titanium alloy wire 1211 has an insulating coating 1212 that provides both electrical insulation and lubrication, reducing resistance when passing through the sheath while also providing insulation. Figure 3 As shown, the braided component 120 can be woven from coated yarns 121 in a clockwise and counterclockwise alternating pattern, or in other patterns. This embodiment does not limit the specific weaving method. Figure 4As shown, a section of the insulating coating 1212 is selectively removed from each coated wire 121 to form multiple electrodes 122. The method used is not limited to mechanical stripping, laser ablation, or chemical etching. The exposed wire core after removing the insulating coating serves as the calibration electrode. The electrodes 122 are electrically insulated from each other by the insulating coating 1212. The wire core of each electrode 122 is conductive and coupled to an external signal processor. Figure 5 As shown, when the braided piece 120 is unfolded, the highly compliant mesh structure can cover most of the area inside the heart chamber, allowing the electrode array to adhere to the tissue and collect electrocardiogram (ECG) signals. The ECG signals can be unipolar or bipolar signals to identify scar areas, low-voltage areas, or arrhythmia mechanisms.

[0032] The conventional heat-setting temperature for annealed nickel-titanium alloy materials is 450~550℃ for 10~30 minutes. Under these conditions, common medical polymer materials decompose and cannot exist stably. To meet the stability and insulation requirements of the braided components, this invention requires lowering the heat-setting temperature of the nickel-titanium alloy wire to prevent the insulating coating from decomposing during the heat-setting of the braided components.

[0033] like Figure 6 As shown, in one or more embodiments, this disclosure provides a method for forming a woven component, comprising the following steps: S1 is used to cold draw nickel-titanium alloy wire to obtain cold-drawn nickel-titanium alloy wire. Annealed nickel-titanium alloy wire is selected, and then the annealed nickel-titanium alloy wire undergoes cold drawing. Cold drawing refers to applying tensile stress to the annealed nickel-titanium alloy wire at room temperature through one or more drawing dies with gradually decreasing diameters, causing it to undergo plastic deformation, thereby obtaining the desired diameter and changing its internal microstructure. After cold drawing with a certain amount of deformation, high-density dislocations and lattice distortion are generated inside the nickel-titanium alloy wire through plastic deformation, storing deformation energy. The introduced high-density dislocations and residual stress provide additional thermodynamic driving force, replacing part of the effect of long-distance atomic diffusion at high temperatures, allowing the heat setting of the nickel-titanium alloy wire to be completed at lower temperatures, such as below 400℃.

[0034] S2 applies an insulating coating to the surface of the cold-drawn nickel-titanium alloy wire; The insulating coating can be applied to the surface of cold-drawn nickel-titanium alloy wire using dip coating, spray coating, or die coating methods. For example, the cold-drawn nickel-titanium alloy wire is passed through a polyimide precursor solution, the coating thickness is controlled by a metering die, followed by pre-baking and imidization, ultimately obtaining a continuous and dense insulating coating of the desired thickness (e.g., 5~20 μm). During subsequent heat setting, the insulating coating isolates oxygen, preventing oxidation of the nickel-titanium alloy wire surface, while also providing electrical insulation.

[0035] The insulating coating is made of high-temperature resistant medical polymer material, preferably polyimide (PI). Polyimide is a commonly used medical polymer material with excellent high-temperature resistance. It can be used stably for a long time (for thousands of hours) in the range of 200-300°C, and can be used stably for a short time (within 60 minutes) at 400°C. Its decomposition temperature is about 500°C.

[0036] S3 involves weaving nickel-titanium alloy wire with an insulating coating onto a mold and then heat-setting it to obtain the target woven part; like Figure 7 As shown, nickel-titanium alloy wires coated with an insulating layer are woven into a mesh structure on the surface of a mold along a predetermined path (such as warp-weft cross or spiral weaving). Then, the high density of dislocations and residual stress of the cold-drawn wire are used to achieve low-temperature shaping, such as heat shaping at temperatures below 400°C. This not only stabilizes the shape of the woven part but also keeps the polyimide insulating coating intact, preventing thermal decomposition and ensuring its insulation performance.

[0037] S4 removes the insulating coating at multiple predetermined locations on the braid to expose the nickel-titanium alloy wires at the corresponding locations to form multiple electrodes.

[0038] After the braided part is formed, the insulating coating on the surface of the nickel-titanium alloy wire is removed at a predetermined location on the braided part to expose the nickel-titanium alloy wire segments at the corresponding locations, forming multiple mutually insulated electrodes, thus obtaining the final braided part. The predetermined location can be a continuous wire segment in the mesh, and the insulating coating is retained between each electrode to ensure mutual electrical insulation and avoid short circuits between electrodes. The insulating coating can be removed by laser ablation, mechanical polishing, or chemical etching. Laser ablation allows for precise control of the removal area without damaging the nickel-titanium substrate.

[0039] like Figures 8 to 10 As shown, after heat treatment at 360℃ for 15 minutes, the cold-drawn nickel-titanium alloy wire achieved the target shape of the braided part. However, after heat treatment at 360℃ for 15 minutes, the conventionally annealed nickel-titanium alloy wire did not achieve the target shape. Finally, after heat treatment at 500℃ for 15 minutes, the conventionally annealed nickel-titanium alloy wire achieved the target shape. These experiments demonstrate that cold drawing significantly reduces the heat setting temperature of the nickel-titanium alloy wire, allowing it to achieve shape fixation below 400℃. In contrast, conventionally annealed nickel-titanium alloy wire cannot achieve heat setting below 400℃.

[0040] The stability of the polyimide coating at different heat treatment temperatures will be further investigated below. Figure 11 As shown, after heat treatment at 360°C for 15 minutes, the polyimide coating on the surface of the coated filament showed no abnormalities. Figure 12As shown, after heat treatment at 500℃ for 15 minutes, the polyimide coating on the surface of the coated filament showed damage and discoloration. The above experiment indicates that the polyimide coating remains stable after heat treatment at 400℃, without decomposition or damage.

[0041] Finally, insulation tests were conducted on the coated wires after heat treatment under the different conditions described above. For example... Figure 13 As shown, the measurement principle is as follows: Coated wire 121 (a nickel-titanium alloy wire with a polyimide coating) after heat treatment under different conditions is immersed in physiological saline 10, and the DC resistance between the physiological saline 10 and the coated wire 121 is tested. If there is no DC resistance between the two, it indicates that the coating surface is intact and undamaged; if there is DC resistance between the two, it indicates that the coating surface is damaged, causing the physiological saline to come into contact with the metal core.

[0042] The specific experimental procedure was as follows: The insulating coating 1212 was removed from one end of the coated wire 121. This removed end was connected to one probe of a multimeter 20. The other end of the coated wire 121 was placed in the air. The middle portion of the coated wire 121 was immersed in physiological saline 10. The other probe of the multimeter 20 was placed in the physiological saline 10. The multimeter 20 was set to the resistance range to test the resistance. The experimental results showed that after heat treatment at 360℃ for 15 minutes, the DC resistance between the coated wire 121 and the physiological saline 10 was insulating, meaning the insulating coating (polyimide coating) 1212 was not damaged. After treatment at 500℃ for 15 minutes, the DC resistance between the coated wire 121 and the physiological saline 10 was not insulating, meaning the insulating coating (polyimide coating) 1212 was damaged.

[0043] From the above experimental process, we can see that: (1) Cold drawing can reduce the heat setting temperature of nickel-titanium alloy wire. Experiments show that cold-drawn nickel-titanium alloy wire can achieve the target shape at 360℃ / 15min, while conventional annealed nickel-titanium alloy wire cannot be shaped at the same temperature and needs to be heated to 500℃. This indicates that the high density of dislocations and residual stress introduced by cold drawing provides an additional driving force for shape memory, reducing the heat setting temperature from the conventional 450~550℃ to below 400℃.

[0044] (2) The polyimide coating remained intact after heat treatment below 400℃; visual observation showed that the coating was undamaged and undiscolored after treatment at 360℃ / 15min; however, the coating showed obvious damage and discoloration after treatment at 500℃ / 15min. This proves that the polyimide coating can exist stably in the temperature range of ≤400℃ without thermal decomposition.

[0045] (3) The polyimide coating exhibits excellent insulation properties after heat treatment below 400℃. Insulation tests (physiological saline immersion method) confirmed that the coated filaments after heat treatment at 360℃ / 15min showed DC insulation with physiological saline, indicating that the coating had no microscopic damage; while the coated filaments after treatment at 500℃ / 15min showed DC conductivity, indicating that the coating had failed. This further verifies that the polyimide coating can maintain reliable electrical insulation properties below 400℃.

[0046] This invention involves cold-drawing nickel-titanium alloy wire to lower its heat-setting temperature to 350-400℃, which falls precisely within the safe temperature range (≤400℃) of the polyimide coating. Heat setting at this temperature yields shaped braids with stable form while ensuring the polyimide coating maintains its appearance and reliable insulation, resolving the technical contradiction of achieving both shaped stability and insulation performance in traditional processes. Furthermore, since the coating also acts as an antioxidant during heat setting, no vacuum or protective atmosphere is required, further reducing manufacturing costs.

[0047] In step S1 above, the cumulative deformation of the nickel-titanium alloy wire during cold drawing is... The percentage is 20% to 70%, preferably 30% to 50%; in, ; A0 is the cross-sectional area of ​​the nickel-titanium alloy wire before cold drawing; A1 is the cross-sectional area of ​​the cold-drawn nickel-titanium alloy wire.

[0048] Specifically, when the cumulative deformation of the cold-drawn nickel-titanium alloy wire is 20% to 70%, it is sufficient to introduce high-density dislocations inside the wire and form complex dislocation entanglements, storing enough deformation energy. This energy is released during heat setting, replacing the long-range atomic diffusion that originally required temperatures above 450°C, thus enabling shape memory to be triggered at lower temperatures.

[0049] When the cumulative deformation of the cold-drawn nickel-titanium alloy wire is less than 20%, the low cold-drawn deformation means that fewer dislocations and lattice distortions are introduced, resulting in insufficient stored deformation energy. During heat setting at 350~400℃, there is a lack of sufficient short-range diffusion channels and nucleation sites to drive stress relaxation and shape memory fixation.

[0050] When the cumulative deformation of the cold-drawn nickel-titanium alloy wire exceeds 70%, the work hardening rate of the nickel-titanium alloy wire is high, and the elongation of the wire will drop sharply, making the wire more fragile. It is prone to brittle fracture at the weaving nodes or when bending, resulting in the inability to weave a complete braid.

[0051] In step S3 above, heat setting can be done once or multiple times, and the temperature of each heat setting is 350℃~400℃, and the time of each heat setting is 12~25min.

[0052] When the shape of the braided part (such as spherical, elliptical or cylindrical) is relatively simple, it can be directly braided on the target shape mold and heat-set once to obtain the target braided part. The above step S3 specifically includes: S311 braiding nickel-titanium alloy wire with insulating coating on the target shape mold and heat-setting once to obtain the target braided part.

[0053] The target shape mold refers to a mold that conforms to the contour of the braided part, and the target braided part refers to a mesh structure that conforms to the shape of the braided part. The heat setting temperature is 350~400℃, preferably 380℃, and the holding time is 12~25min, preferably 15min. During this process, the high-density dislocations and residual stress inside the cold-drawn nickel-titanium alloy wire provide the driving force, causing stress relaxation and microstructure reconstruction in the nickel-titanium alloy wire, thereby fixing the shape imparted by the target shape mold. After the heat setting is completed, the mold is removed and allowed to cool naturally to room temperature in air, or cooled in the furnace. During the cooling process, the shape of the braided part no longer changes. The mold material can be high-temperature resistant stainless steel or ceramic.

[0054] For simple-shaped woven parts, only one weaving and one heat setting are needed to fix the shape, eliminating the need for intermediate mold making, multiple disassembly and assembly, and multiple heat setting cycles. This shortens the production cycle, improves production efficiency, and reduces production costs. Furthermore, under low-temperature short-time conditions of 350~400℃ for 12~25 minutes, combined with 30%~50% cold-drawn filaments, the woven parts can accurately replicate the mold shape without springback or distortion, maintaining good shape during long-term storage or use. The heat setting temperature (≤400℃) falls within the short-time temperature resistance range of the polyimide coating, and the coating does not decompose, carbonize, or peel off, maintaining excellent electrical insulation properties and oxidation resistance.

[0055] When the shape of the woven part is complex (e.g., asymmetrical heart shape, pear shape with concave section, or variable diameter curved surface), one or more intermediate shape molds can be used for heat setting first, and the target shape mold can be used for heat setting finally. Step S3 specifically includes: S321 braids nickel-titanium alloy wire with an insulating coating on the first mold and performs the first heat setting to obtain the first shaped braided part; S322 fixes the first-shape woven part onto the target-shape mold for a second heat setting to obtain the target woven part.

[0056] Specifically, the first mold is an intermediate mold with a lower geometric complexity than the target woven part. For example, if the target woven part is an asymmetrical heart shape (containing a deep recess), the first mold can be designed as a symmetrical ellipsoid with a diameter 5% to 10% larger than the target size, and the recessed area is filled with a smooth curved surface. The shape of the first mold should ensure that the bending angle of the nickel-titanium alloy wire is small and there is no local stress concentration during weaving.

[0057] The nickel-titanium alloy wire with an insulating coating is first woven on a first mold and then subjected to a first heat setting. The heat setting temperature can be 345-355℃, preferably 350℃, and the heat treatment time is 12-20 minutes, preferably 15 minutes. Because the first mold has a simple shape, the wire tension is uniform during weaving, eliminating the need for forced bending to complex curved surfaces, making the operation convenient. After weaving, the woven part initially fits the first mold, exhibiting an intermediate shape without significant warping or mesh distortion. After heat setting, the intermediate shaped woven part structure is obtained, which is the first shaped woven part.

[0058] The target mold has the final complex shape required, including asymmetrical curved surfaces, local concave or variable diameter structures, etc. The first-shape braided part is removed from the first mold. Since the braided part has a certain degree of self-support after the first heat setting, it is not easily deformed during removal. Then, the first-shape braided part is fixed to the target mold using high-temperature resistant filaments, elastic clips, or temporary binding tape to ensure that the first-shape braided part is tightly attached to all curved surfaces of the target mold, especially ensuring that the filaments at concave or corner locations are in full contact with the mold surface without any gaps. Finally, the target mold with the braided part is placed in an air furnace for a second heat setting treatment. The second heat setting temperature can be 370-390℃, preferably 380℃, and the heat setting time is 12-20 minutes, preferably 15 minutes. At this time, the braided part further deforms from the first intermediate shape to the target complex shape to obtain the target braided part.

[0059] Alternatively; step S3 above specifically includes: S331 weaving nickel-titanium alloy wire with an insulating coating on the first mold and performing a first heat setting to obtain a first-shaped woven part; S332 The first shaped woven piece is sequentially fixed onto one or more second molds for a second heat setting to obtain the second shaped woven piece; S333 fixes the second-shaped woven part onto the target-shaped mold for a third heat setting to obtain the target woven part.

[0060] Specifically, when the shape of the woven part is extremely complex, two-step heat setting may still lead to excessive local stress due to excessive deformation in a single step. In this case, a stepwise approximation process using three or more molds is required. The first mold is the simplest intermediate shape, such as spherical or cylindrical. The woven part in the first shape is woven and heat-set on the first mold. The heat setting temperature can be 345-355℃, preferably 350℃, and the heat setting time is 12-20 minutes, preferably 15 minutes.

[0061] Depending on the complexity of the target shape, one, two or more second molds can be set up. The geometry of each second mold is closer to the target shape of the woven part than the previous mold. That is, the geometry of the first second mold is closer to the target shape of the woven part than the first mold; the geometry of the second second mold is closer to the target shape of the woven part than the first second mold; the geometry of the third second mold is closer to the target shape of the woven part than the second second mold, and so on.

[0062] The first-shaped braided component is removed from the first mold and fixed onto the first second mold for a second heat setting. The temperature for the second heat setting is 355-365℃, preferably 360℃, and the heat setting time is 12-20 minutes, preferably 15 minutes. If there are multiple second molds, the braided component is transferred sequentially to the next second mold for heat setting. After each heat setting, the shape of the braided component gradually approaches the target shape, the internal stress is gradually released, and the insulating coating remains within a safe temperature window. After heat setting on all the second molds, a second-shaped braided component is obtained, whose shape is close to the target shape of the braided component.

[0063] Finally, the second-shaped woven part is removed from the last second mold and fitted onto the target-shaped mold, ensuring that the woven part closely conforms to all complex curved surfaces. A third heat setting is then performed to obtain a precise target woven part with a stable shape. The temperature for the third heat setting can be 370-390℃, preferably 380℃, and the heat setting time is 12-20 minutes, preferably 15 minutes. In this embodiment, a single large deformation is decomposed into multiple small deformations, and the amount of deformation in each deformation is controlled within the safe tolerance range of the material and the insulating coating, which significantly reduces local stress concentration and prevents buckling of the nickel-titanium alloy wire, mesh distortion or microcracks in the insulating coating.

[0064] It should be noted that when the braided part requires multiple heat setting processes, the temperature of each subsequent heat setting should be higher than the temperature of the previous heat setting, but the temperature of each heat setting must be lower than or equal to 400℃. The cold-drawn nickel-titanium alloy wire stores a high density of dislocations. During the first heating, a relatively low energy input is sufficient to activate the short-range rearrangement of dislocations, releasing most of the residual stress generated during the weaving process. This is sufficient to fix the wire to a simple shape (such as a sphere or ellipsoid) on a mold. To further bend the already fixed simple-shaped braided part into a complex shape (such as an asymmetric heart shape or a concave structure), greater mechanical resistance needs to be overcome, and long-range atomic diffusion needs to be induced to establish a precise twinned structure. This requires a higher thermodynamic energy, therefore, it is necessary to ensure that the temperature of each subsequent heat setting is higher than the temperature of the previous heat setting.

[0065] When the braided part undergoes multiple heat setting processes, depending on the ease of processing, the operation of removing the insulating coating to form electrodes can be performed on the first morphology of the braided part after the first heat setting, or in any step after the first heat setting. This embodiment does not impose specific limitations.

[0066] Optionally, after removing the insulating coating at multiple predetermined locations on the braid to expose the nickel-titanium alloy wires at the corresponding locations to form multiple electrodes, step S4 further includes: S5 performs surface treatment on exposed nickel-titanium alloy wires.

[0067] On the final braided product, the exposed nickel-titanium alloy wires after the insulation coating has been removed can undergo further surface treatment to improve their electrical properties and biocompatibility. Specific surface treatment processes can include removing the surface oxide layer and adding a specific coating (such as iridium oxide, platinum black, conductive polymer, etc.).

[0068] This application also provides an embodiment of a catheter, which can be a mapping catheter or an ablation catheter, such as... Figure 14 As shown, the catheter includes a catheter body 110 and a braid 120 installed at the distal end of the catheter body 110. The braid is made by the braid forming method described in any of the above embodiments.

[0069] like Figure 1 As shown, the woven component 120 is a mesh structure woven from multiple coated filaments 121, as... Figure 2 As shown, the coated wire 121 includes a nickel-titanium alloy wire 1211 and an outer insulating coating 1212. (As...) Figure 4 As shown, at least a portion of the coated filament 121 has a portion with the insulating coating 1212 partially removed and electrically contactable with the outside world to form an electrode 122 for electrophysiological mapping or ablation.

[0070] like Figure 1As shown, the catheter also includes a connector 130 and a mandrel 140. The proximal end of a nickel-titanium alloy wire 1211 is attached to the catheter body 110, and the distal end of the nickel-titanium alloy wire 1211 converges to the distal end of the connector 130, forming a concave structure facing the proximal end. The mandrel 140 passes through the inner lumen of the catheter body 110 and extends axially along the catheter body 110. The distal end of the mandrel 140 connects to the proximal end of the connector 130 to drive the connector 130, while the proximal end of the mandrel 140 extends to the proximal end of the catheter body 110. By manipulating the axial position of the mandrel 140 relative to the catheter body 110 (e.g., moving it towards the distal or proximal end of the catheter body 110), the braided section 120 can be switched between a contracted and an expanded state to adjust the shape and size of the braided section 120.

[0071] Furthermore, such as Figure 1 As shown, two far-field electrodes 200 are also spaced apart on the outer surface of the connector 130. Because the far-field electrodes 200 are far from the ablation or mapping site, they can record a large-amplitude and stable ventricular far-field signal. This signal can serve as a reference for the electrode array on the braid 120, helping the system to distinguish the true target near-field potential from far-field interference from ventricular myocardium in real time, removing far-field noise and eliminating signal interference during the procedure. The far-field electrodes 200, combined with the magnetic sensor, can also effectively ensure the accurate positioning and signal acquisition of the distal end of the catheter.

[0072] The braided component 120 formed using the above embodiments has a suitable elastic modulus and sufficient flexibility. The braided component can be easily pulled into the sheath and, after being pushed out, can quickly and evenly unfold automatically to a preset shape. After unfolding, it exhibits good morphological stability and high compliance, covering most of the area within the heart chambers. This allows the electrode array to adhere closely to the tissue, acquiring multi-point electrical signals within the heart chambers for high-precision electrophysiological mapping or ablation of target tissues. Furthermore, the polyimide insulating coating does not decompose after the braided component is heat-set, exhibiting excellent insulation properties. The electrodes maintain complete insulation between them, preventing short circuits between adjacent electrodes even in a saline environment, ensuring patient safety.

[0073] When using the braided component 120 formed in the above embodiment as a mapping catheter, the braided component 120 of the mapping catheter is first completely retracted into the sheath and delivered to the target cardiac chamber via the vascular puncture path. Under X-ray or intracardiac ultrasound guidance, the distal end of the catheter body 110 is pushed out of the sheath, and the braided component 120 automatically unfolds and adheres to the endocardium. By connecting to an external mapping system, intracardiac electrocardiograms are acquired sequentially or simultaneously at each electrode location to construct a three-dimensional electroanatomical map. After mapping is completed, the braided component 120 is retracted into the sheath and withdrawn from the body.

[0074] When using the braided component 120 formed in the above embodiment as an ablation catheter, the braided component 120 of the ablation catheter is first completely retracted into the sheath. The sheath is then advanced to the target cardiac chamber (e.g., the left atrium) via femoral vein puncture. Guided by a three-dimensional mapping system, the sheath is advanced, and the braided component 120 automatically unfolds and adheres to the atrial wall. After confirming good contact between the electrode and tissue through the mapping function, the radiofrequency power, perfusion rate, and upper temperature limit are set, and the electrodes are selected sequentially or simultaneously for ablation. After ablation is completed, the braided component 120 is retracted into the sheath and removed from the body.

[0075] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0076] It should be noted that the above embodiments can be freely combined as needed. The above description is only a preferred embodiment of this application. It should be pointed out that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the protection scope of this application.

Claims

1. A method for forming a woven component, characterized in that, Includes the following steps: Cold drawing is performed on nickel-titanium alloy wire to obtain cold-drawn nickel-titanium alloy wire; An insulating coating is applied to the surface of the cold-drawn nickel-titanium alloy wire; The nickel-titanium alloy wire with an insulating coating is woven on a mold and then heat-set to obtain the target woven part; The insulating coating is removed at multiple predetermined locations on the braid to expose the nickel-titanium alloy wires at the corresponding locations to form multiple electrodes.

2. The method for forming a woven component according to claim 1, characterized in that, Cumulative deformation of nickel-titanium alloy wire after cold drawing It ranges from 20% to 70%; in, ; A0 is the cross-sectional area of ​​the nickel-titanium alloy wire before cold drawing; A1 is the cross-sectional area of ​​the cold-drawn nickel-titanium alloy wire.

3. The method for forming a woven component according to claim 1, characterized in that, The insulating coating is a polyimide coating.

4. The method for forming a woven component according to claim 1, characterized in that, The heat setting can be done in one step or multiple steps, with each heat setting temperature being 350℃~400℃ and each heat setting time being 12~25 minutes.

5. The method for forming a woven component according to claim 4, characterized in that, When the heat setting is a single heat setting, the process of weaving nickel-titanium alloy wire with an insulating coating onto a mold to form a braided part and then performing heat setting to obtain the target braided part specifically includes: Nickel-titanium alloy wire with an insulating coating is woven on a mold of the target shape and then heat-set once to obtain the target woven part.

6. The method for forming a woven component according to claim 4, characterized in that, When the heat setting is a multiple heat setting process, the step of weaving and heat setting the nickel-titanium alloy wire with an insulating coating on a mold to obtain the target woven part specifically includes: Nickel-titanium alloy wire with an insulating coating is woven on the first mold and subjected to the first heat setting to obtain the first shaped woven part. The first shaped woven part is fixed on the target shaped mold for a second heat setting to obtain the target woven part.

7. The method for forming a woven component according to claim 6, characterized in that, The temperature for the first heat setting is 345-355℃, and the heat setting time is 12-20 minutes. The second heat setting temperature is 370-390℃, and the heat setting time is 12-20 minutes.

8. The method for forming a woven component according to claim 4, characterized in that, When the heat setting is a multiple heat setting process, the step of weaving and heat setting the nickel-titanium alloy wire with an insulating coating on a mold to obtain the target woven part specifically includes: Nickel-titanium alloy wire with an insulating coating is woven on the first mold and subjected to the first heat setting to obtain the first shaped woven part. The first shaped woven piece is sequentially fixed onto one or more second molds for a second heat setting to obtain the second shaped woven piece; The second-shaped woven part is fixed on the target-shaped mold for a third heat setting to obtain the target woven part.

9. The method for forming a woven component according to claim 8, characterized in that, The temperature for the first heat setting is 345-355℃, and the heat setting time is 12-20 minutes. The second heat setting temperature is 355-365℃, and the heat setting time is 12-20 minutes; The temperature for the third heat setting is 370-390℃, and the heat setting time is 12-20 minutes.

10. A method for forming a woven component according to claim 6 or 8, characterized in that, In the multiple heat setting processes, the temperature of the later heat setting is higher than the temperature of the previous heat setting.

11. The method for forming a woven component according to claim 1, characterized in that, The multiple preset positions are respectively filament segments in the braided mesh, and the electrodes are insulated from each other by the insulating coating.

12. The method for forming a woven component according to claim 1, characterized in that, After removing the insulating coating at multiple predetermined locations on the braid to expose the nickel-titanium alloy wires at the corresponding locations to form multiple electrodes, the process further includes: The exposed nickel-titanium alloy wire is surface treated.

13. A mapping catheter, characterized in that, It includes a catheter body and a braided component installed at the distal end of the catheter body, the braided component being manufactured by the forming method of the braided component according to any one of claims 1-12.

14. An ablation catheter, characterized in that, It includes a catheter body and a braided component installed at the distal end of the catheter body, the braided component being manufactured by the forming method of the braided component according to any one of claims 1-12.

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