Ablation microcatheter

Abstract

The application relates to an ablation microcatheter. The ablation microcatheter comprises a base, an inner tube, a flexible circuit strip, a support tube, an outer tube, a plurality of electrode rings, a tip and a driving mechanism; the base is provided with an inner cavity; the inner tube is in communication with the inner cavity; the flexible circuit strip is wound outside the inner tube, and the flexible circuit strip extends axially spirally along the inner tube; the flexible circuit strip comprises a sticking layer, an adhering layer and a plurality of electrode pieces; the sticking layer and the adhering layer are connected; the sticking layer is located on the side of the adhering layer facing the inner tube; the plurality of electrode pieces are distributed at intervals on the side of the adhering layer away from the sticking layer; and the electrode pieces extend axially spirally along the inner tube; the outer tube is sleeved outside the inner tube, and the flexible circuit strip is located inside the outer tube; the electrode rings are sleeved at intervals outside the outer tube, and the electrode rings are electrically connected with the electrode pieces; and the driving mechanism is installed on the base, and the driving mechanism drives the inner tube to bend. The scheme provided by the application can ensure that the electrode pieces and the electrode rings remain closely connected after the inner tube is bent for many times.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical devices, in particular to an ablation microcatheter. BACKGROUND

[0002] Cardiac catheter ablation technology is to insert a catheter through the groin or neck area. The electrode at the tip of the catheter can help doctors detect electrophysiological characteristics and determine the location of abnormal electrical signals. Once the precise location is determined, the doctor can deliver energy through the catheter to ablate the local area.

[0003] Catheter ablation technology has been widely used in the clinical ablation of various arrhythmias, such as atrial fibrillation, premature ventricular contraction, and ventricular tachycardia. With the deepening understanding of arrhythmia mechanisms and the continuous improvement of ablation devices, the success rate of catheter ablation of arrhythmias has been significantly improved, but due to the limitations of ablation devices on the market, the success rate of ablation of some arrhythmias is limited. The most prominent performance is the catheter ablation treatment of persistent atrial fibrillation and premature ventricular contraction / ventricular tachycardia.

[0004] First, in recent years, it has been found that Marshall vein plays an important role in the mechanism of the occurrence and maintenance of persistent atrial fibrillation. Marshall vein is one of the trigger sites of atrial fibrillation; there is a rich distribution of autonomic nerves on Marshall vein / ligament; isolation of the left pulmonary vein and linear block of the mitral valve isthmus play an auxiliary role. At present, most of the clinical ablation of the corresponding area is achieved by Marshall vein alcohol infusion, but this method still has limitations: 1. In the process of ablation, the determination of Marshall vein as the trigger site of atrial fibrillation is based on indirect evidence, and there is no direct evidence to determine the accurate mechanism. 2. Marshall vein alcohol infusion is non-selective, and the damaged myocardium and the distribution of Marshall vein and its branch vessels are closely related. The process of alcohol infusion is uncontrollable, while the microcatheter can achieve precise ablation. 3. Marshall vein is in communication with the left atrium, and even the superior vena cava. During the infusion process, alcohol enters these parts and can damage the endothelium, increasing the risk of thrombosis.

[0005] Therefore, there are ablation catheters on the market that use electrode rings to generate high-voltage pulse energy to the target tissue to achieve effective ablation. The rigid electrode ring and the rigid wire are bonded together by welding. Since the position of the electrode ring and the wire in the catheter is relatively fixed after assembly, however, in the actual clinical use process, in order to make the ablation catheter adapt to the shape of the patient's blood vessels and reach different positions in various shapes, the handle end of the ablation catheter is controlled to bend the head end pipe into different shapes, which will inevitably bring different degrees of bending effect to the different electrode rings of the head end pipe. Since the electrode and the wire are connected by welding, after repeated bending, the electrode ring and the wire are easily separated from each other, and the ablation catheter after separation will lose its original function. SUMMARY

[0006] To solve or partially solve the problems in the related art, the application provides an ablation microcatheter, which can improve the structural strength of an inner tube.

[0007] The first aspect of the application provides an ablation microcatheter, comprising a base, an inner tube, a flexible circuit strip, a support tube, an outer tube, a plurality of electrode rings and a driving mechanism; the base is provided with an inner cavity; the inner tube is in communication with the inner cavity; the flexible circuit strip is outside the inner tube, and the flexible circuit strip extends spirally along the axial direction of the inner tube; the flexible circuit strip comprises a sticking layer, an adhering layer and a plurality of electrode pieces; the sticking layer and the adhering layer are connected; the sticking layer is located on the side of the adhering layer facing the inner tube; the plurality of electrode pieces are distributed at intervals on the side of the adhering layer away from the sticking layer; the electrode pieces extend spirally along the axial direction of the inner tube; the outer tube is sleeved outside the inner tube, and the flexible circuit strip is located inside the outer tube; the electrode rings are sleeved at intervals outside the outer tube; the electrode rings correspond one-to-one to the electrode pieces; the electrode rings are electrically connected to the electrode pieces; the driving mechanism is installed on the base; and the driving mechanism drives the inner tube to bend.

[0008] Further, the ablation microcatheter further comprises a connector and a connecting tube; the two ends of the connecting tube are connected to the connector and the base respectively; and one end of the electrode piece is electrically connected to the connector.

[0009] Further, the flexible circuit strip further comprises a reinforcing layer; the reinforcing layer corresponds one-to-one to the electrode pieces; the reinforcing layer is wound on the outer surface of the outer tube; one end of the reinforcing layer penetrates through the outer tube and is connected to the electrode piece; the electrode ring abuts against the reinforcing layer and is electrically connected to the reinforcing layer.

[0010] Further, the inner tube is provided with a first guide wire cavity; the first guide wire cavity is in communication with the inner cavity; and the end of the base away from the inner tube is provided with a perforation; the perforation is in communication with the inner cavity.

[0011] Further, the inner tube is provided with a second guide wire cavity; the outer tube is provided with an outer through hole; the inner tube is provided with an inner through hole corresponding to the outer through hole; and the outer through hole is in communication with the second guide wire cavity through the inner through hole.

[0012] Further, the ablation microcatheter further comprises a support tube; the support tube is sleeved outside the inner tube; and the support tube is used for reinforcing the inner tube.

[0013] Further, the ablation microcatheter further comprises a tip; the tip is connected to the end of the inner tube away from the base; and the hardness of the end of the support tube close to the tip gradually decreases towards the tip.

[0014] Further, the inner tube is provided with a liquid delivery cavity, the liquid delivery cavity is communicated with the inner cavity, the end head is provided with a liquid outlet hole, and the liquid delivery cavity is communicated with the liquid outlet hole.

[0015] Further, the hardness of the end head gradually decreases in the direction away from the inner tube.

[0016] Further, the electrode ring comprises an electrode piece and an adhesive layer, the electrode piece comprises an inner layer and an outer layer, the outer layer surrounds the inner layer, the inner layer is connected with the outer layer, the inner layer is electrically connected with the electrode sheet, and the outer layer is bonded with the outer tube through the adhesive layer.

[0017] The technical scheme provided in the application can have the following beneficial effects: by arranging the support tube outside the inner tube, the strength of the ablation microcatheter at the position of the inner tube is improved by reinforcing the inner tube with the support tube, and the ablation microcatheter is prevented from being broken when being bent and stretched in the blood vessel.

[0018] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the application. BRIEF DESCRIPTION OF DRAWINGS

[0019] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout the several views, and in which:

[0020] Figure 1 is a structural schematic diagram of the ablation microcatheter shown in the embodiments of the application;

[0021] Figure 2 is Figure 1 is an enlarged schematic diagram of A in FIG. 4;

[0022] Figure 3 is a schematic diagram of the connection between the electrode sheet and the electrode ring;

[0023] Figure 4 is a sectional view of the flexible circuit strip;

[0024] Figure 5 is a sectional view of the electrode ring;

[0025] Figure 6 is a structural schematic diagram of the driving mechanism;

[0026] Figure 7 is a structural schematic diagram of the ablation microcatheter OTW structure of the application.

[0027] Reference signs: base 1; inner tube 2; support tube 3; outer tube 4; outer through hole 41; electrode ring 5; outer layer 51; inner layer 52; adhesive layer 53; end 6; connector 7; connecting tube 8; flexible circuit strip 9; adhesive layer 91; attachment layer 92; electrode sheet 93; reinforcing layer 94; driving mechanism 10; pull wire 101; slider 102; push handle 103. DETAILED DESCRIPTION

[0028] Embodiments of the present application will be described in more detail with reference to the drawings. Although embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present application will be thorough and complete, and will fully convey the scope of the present application to those skilled in the art.

[0029] It should be understood that although the terms "first", "second", "third", etc. are used to describe various information in the present application, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, the first information can also be referred to as the second information, and similarly, the second information can also be referred to as the first information without departing from the scope of the present application. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified.

[0030] In the description of the present application, it should be understood that the terms "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0031] Unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood broadly, for example, it can be fixed connection, or detachable connection or integral; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0032] To solve the above problems, the present application provides an ablation microcatheter, which can improve the structural strength of the inner tube.

[0033] The technical solutions of the embodiments of this application are described in detail below with reference to the accompanying drawings.

[0034] Figure 1 This is a schematic diagram of the structure of the ablation microcatheter shown in the embodiments of this application; Figure 5 This is a cross-sectional view of the electrode ring; Figure 6 This is a schematic diagram of the drive mechanism.

[0035] See Figure 1 , Figure 5 and Figure 6 The ablation microcatheter includes a base 1, an inner tube 2, an outer tube 4, multiple electrode rings 5, an end cap 6, a flexible circuit strip 9, and a drive mechanism 10. The base 1 has an inner lumen through which contrast agents, guide wires, or other probes can pass. The inner tube 2 is connected to the inner lumen; when a guide wire is needed, it can be inserted into the inner tube 2 from the inner lumen; when contrast agents need to be introduced into the inner tube 2, they can flow into the inner tube 2 from the inner lumen.

[0036] Figure 3 This is a schematic diagram of the connection between the electrode sheet and the electrode ring.

[0037] See Figure 3 and Figure 5 The flexible circuit strip 9 is located outside the inner tube 2. It includes an adhesive layer 91, an attachment layer 92, and multiple electrode pieces 93. The adhesive layer 91 and the attachment layer 92 are bonded together and are both made of insulating material. The adhesive layer 91 is located on the side of the attachment layer 92 facing the inner tube. Multiple electrode pieces 93 are spaced apart on the side of the attachment layer 92 facing away from the adhesive layer 91. The adhesive layer 91 extends spirally along the axial direction of the inner tube 2, and the attachment layer 92 also extends spirally along the axial direction of the inner tube 2. The electrode pieces 93 are attached to the surface of the attachment layer 92 and extend spirally along the axial direction of the inner tube 2. When the inner tube 2 bends, the electrode pieces 93 also bend accordingly. Because adjacent electrode pieces 93 are spaced apart, short circuits will not occur between adjacent electrode pieces 93. The outer tube 4 is made of polymer material and is fitted outside the inner tube 2. The flexible circuit strip is located inside the outer tube 4, which protects the flexible circuit strip 9.

[0038] Figure 2 yes Figure 1 Enlarged diagram of A in the middle; Figure 4 This is a cross-sectional view of the flexible circuit strip.

[0039] See Figures 1-5A plurality of electrode rings 5 are sleeved on the outer tube 4 along the axial direction of the outer tube 4, the electrode rings 5 correspond to the electrode pieces 93 one by one, the lengths of any two electrode pieces 93 are different, and each electrode ring 5 is electrically connected with only one electrode piece 93. When the electrode piece 93 reaches the position corresponding to the electrode ring 5, the electrode piece 93 is electrically connected with the electrode ring 5, at this time, the electrode piece 93 no longer extends along the axial direction of the inner tube 2, and the remaining electrode pieces 93 continue to extend along the axial direction of the inner tube 2 until reaching the corresponding electrode ring 5. When the electrode needs to be used for ablation, the electrode is powered on, and an electric field is formed between two adjacent electrodes, wherein different electric field strengths can be obtained by changing the voltage or the distance from the electrode. The material of the electrode ring 5 can be any suitable metal material, and the commonly used material is a platinum-iridium alloy or a gold material electrode. According to the actual needs, different electrode spacing and polarity combination modes are designed, the electrode ring 5 can withstand a voltage of 4000V, and once the target catheter is positioned, the tail end is connected with the pulse emission device, and high-voltage pulse energy can be effectively transmitted to the target tissue through the front electrode ring 5 to achieve effective ablation. The end head 6 is connected to the end of the inner tube 2 away from the base 1, the end head 6 is made of soft material, the inner diameter of the end head 6 can be selected to match a commonly used coronary guide wire with a diameter of 0.014", and the end head 6 can prevent the ablation microcatheter from injuring the blood vessel when the ablation microcatheter is inserted into the blood vessel.

[0040] Referring to Figure 6 In some embodiments, a driving mechanism is mounted on the base 1, and the driving mechanism drives the inner tube 2 to bend. The driving mechanism 10 includes a pull wire 101, a sliding block 102 and a push handle 103, one end of the pull wire 101 is connected with the end head 6, the other end of the pull wire 101 is fixed to the base 1 through a lock buckle, the sliding block 102 and the push handle 103 are fixed, the sliding block 102 is fixed with the outer tube 4, and the push handle 103 can move relative to the base 1. When a user pushes the push handle 103 towards the end head 6, the outer tube 4 and the inner tube 2 will bend, which facilitates the outer tube 4 to extend in the blood vessel in a meandering manner.

[0041] Referring to Figure 1 and Figure 3 The ablation microcatheter further includes a connector 7 and a connecting tube 8, two ends of the connecting tube 8 are connected with the connector 7 and the base 1 respectively, and one end of the electrode piece is electrically connected with the connector 7. The connector 7 can be connected with a multi-channel instrument or the like instrument, the electrode ring 5 can simultaneously record and transmit the electrical signal to the connector 7 through the electrode piece, and the connector 7 displays the potential of the part abutting against the electrode ring 5 in real time through the external instrument to help the operator to judge the ablation condition.

[0042] Referring to Figure 2 and Figure 5The flexible circuit strip 9 further comprises reinforcing layers 94, the number of the reinforcing layers 94 corresponds to the number of the electrode pieces 93, the reinforcing layers 94 are wound on the outer surface of the outer tube 4, one end of the reinforcing layer 94 passes through the outer tube 4 and is connected with the electrode piece 93, the reinforcing layer 94 and the electrode piece 93 are in an integrated structure, the reinforcing layer 94 is made of a long strip-shaped metal sheet, the metal sheet is wound on the outer surface of the outer tube for several turns to form the reinforcing layer 94, the electrode ring 5 abuts against and wraps the reinforcing layer 94, the electrode ring 5 is electrically connected with the reinforcing layer 94, the electrode ring 5 and the reinforcing layer 94 are in large-area contact, so that the electrode ring 5 and the reinforcing layer 94 are in close contact in electrical conductivity, and good electrical conductivity between the electrode ring 5 and the electrode piece 93 is ensured.

[0043] Referring to Figure 1 and Figure 5 The ablation microcatheter further comprises a support tube 3, the inner tube 2 is made of a high polymer material, the support tube 3 is sleeved outside the inner tube 2, and the support tube 3 can be in contact with or not in contact with the inner tube 2. The support tube 3 is used for reinforcing the inner tube 2, so as to improve the strength of the ablation microcatheter at the position of the inner tube 2 and avoid breakage of the ablation microcatheter when the ablation microcatheter is bent and stretched in the blood vessel. The outer tube 4 is sleeved outside the support tube 3, and specifically, the outer tube 4 is attached to the outer surface of the support tube 3. The inner tube 2, the outer tube 4 and the support tube 3 can increase the adjustable bending function, the adjustable bending design of which can be similar to the existing ten-level adjustable bending mapping catheter, and the operator can operate the handle to make the distal electrode ring 5 reach the target position, so as to achieve better abutting effect. The reinforcing layer 94 passes through the support tube 3 and the outer tube 4 from the electrode piece to the outer surface of the outer tube 4, and specifically, the surface of the reinforcing layer 94 facing the support tube 3 can be coated with insulating paint. Figure 5 In the embodiment, the flexible circuit strip is attached to the inner tube 2 through the adhesive layer 91, and the surface of the electrode piece 93 needs to be insulated when the flexible circuit strip 9 is wound on the outer surface of the inner tube 2, so as to avoid short circuit between the electrode piece 93 and the support tube 3. In other embodiments, the flexible circuit strip 9 is attached to the support tube 3 through the adhesive layer 91.

[0044] Figure 7 is a structural schematic view of the OTW structure of the ablation microcatheter.

[0045] Referring to Figure 7 In some embodiments, the ablation microcatheter is in an OTW structure, the connector 7 is located on one side of the base 1, the connector 7 is not in communication with the inner cavity, the inner tube 2 is provided with a first guide wire cavity, the first guide wire cavity is used for passing through a guide wire, the first guide wire cavity is in communication with the inner cavity, and the end of the base 1 away from the inner tube 2 is provided with a through hole, the through hole is in communication with the inner cavity, and the guide wire can pass through the through hole, the inner cavity and the first guide wire cavity in sequence.

[0046] Referring to Figures 1-3In some embodiments, the ablation microcatheter has an Rx structure, with the inner tube 2, base 1, and connector 7 aligned in a straight line. The inner tube 2 has a second guidewire cavity for the guidewire to pass through. The outer tube 4 has an external through hole 41, and the inner tube 2 has an internal through hole corresponding to the external through hole 41. The external through hole 41 is connected to the second guidewire cavity through the internal through hole, allowing the guidewire to pass sequentially through the external through hole 41 and the internal through hole before entering the second guidewire cavity 23.

[0047] In some embodiments, the inner tube 2 is provided with an infusion chamber, and no guidewire passes through the inner tube 2. The infusion chamber is connected to the inner cavity. The end 6 is provided with an outlet hole, and the surface of the end 6 is smooth. The infusion chamber is connected to the outlet hole, allowing the ablation microcatheter to directly reach the target location to complete ablation. In specific use, contrast agents or other liquids can be injected into the infusion chamber to achieve ablation. Simultaneously, the contrast agent flows out from the outlet hole and is infused around the electrode ring 5. The contrast agent can be physiological saline. See also Figures 1-3 In some embodiments, the hardness of the support tube 3 near the end 6 gradually decreases towards the end 6, and the distal end of the support tube 3 can be made gradually flexible through machining, so that the support tube 3 can bend in blood vessels while ensuring sufficient strength, thereby allowing it to extend in complex blood vessels. The support tube 3 is made of stainless steel, nickel-titanium alloy, or polymer material, and the polymer material can be PEEK material.

[0048] See Figures 1-2 In some embodiments, the hardness of the tip 6 gradually decreases in the direction away from the inner tube 2, making the tip 6 sufficiently soft to reduce the risk of puncturing the blood vessel when it is inserted into the blood vessel. Preferably, the tip 6 can be made of radiopaque material, and the position of the tip 6 and the inner tube 2 can be determined by taking an X-ray when the tip 6 is inserted into the blood vessel.

[0049] See Figure 2 and Figure 5 In some embodiments, the electrode ring 5 includes an electrode element and an adhesive layer 53. The electrode element has a T-shaped cross-section and includes an integrally formed inner layer 52 and an outer layer 51. The outer layer 51 surrounds the inner layer, and the inner layer 52 is connected to the outer layer 51. The width of the outer layer 51 is larger than the width of the inner layer 52. The inner layer 52 is electrically connected to the electrode sheet, and the outer layer 51 is bonded to the outer tube 4 through the adhesive layer 53. The adhesive layer 53 is sandwiched between the outer tube 4 and the outer layer 51. This structure can ensure that the electrode element is electrically connected to the electrode sheet 93 while firmly fixing the electrode element to the outer tube 4. When the electrode ring 5 is unfolded, it is a long strip-shaped structure. When it is necessary to install the electrode ring onto the outer tube 4, the side of the adhesive layer 53 can face the surface of the outer tube 4, one end of the electrode ring 5 can be attached to the outer tube 4, and then the electrode ring 5 can be wrapped around the outer tube 4 and attached to the outer tube 4, making the installation process of the motor ring 5 simpler.

[0050] In some embodiments, the electrode ring 5 is a ring-shaped metal sheet, and the electrode ring 5 is welded to the outer surface of the outer tube 4.

[0051] The solutions of the present application have been described in detail above with reference to the accompanying drawings. In the above-described embodiments, the description of each embodiment is focused on respectively, and the parts not described in detail in a certain embodiment can be referred to the relevant description of other embodiments. It should also be known by those skilled in the art that the actions and modules involved in the specification are not necessarily required by the present application. In addition, it can be understood that the steps in the method of the embodiments of the present application can be adjusted, combined and reduced in sequence according to actual needs, and the modules in the device of the embodiments of the present application can be combined, divided and reduced according to actual needs.

[0052] The above has described various embodiments of the present application, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments. The choice of terms used herein is intended to best explain the principles of the embodiments, practical application or improvement of the technology in the market, or to enable other ordinary skilled in the art to understand the embodiments disclosed herein.

Claims

1. An ablation microcatheter, comprising: The utility model relates to a kind of flexible circuit belt and electrode ring, including: Base, the base is equipped with inner cavity; Inner tube, the inner tube is communicated with the inner cavity; Flexible circuit belt, the flexible circuit belt is outside the inner tube, and the flexible circuit belt spirally extends along the axial direction of the inner tube, the flexible circuit belt includes adhesive layer, adhesive layer, multiple electrode pieces and reinforcing layer, the adhesive layer and the adhesive layer are connected, the adhesive layer is located the side of the adhesive layer towards inner tube, multiple the electrode piece is distributed in the adhesive layer back to the adhesive layer one side away from the adhesive layer, and the electrode piece spirally extends along the axial direction of the inner tube; Outer tube, the outer tube is sleeved outside the inner tube, and the flexible circuit belt is located in the outer tube; Multiple electrode rings, the electrode ring is spaced and is sleeved outside the outer tube, and the electrode ring corresponds with the electrode piece one by one, and the electrode ring is electrically connected with the electrode piece; Driving mechanism, the driving mechanism is installed to the base, and the driving mechanism drives the inner tube to bend; The reinforcing layer corresponds with the electrode piece one by one, the reinforcing layer is wound on the outer surface of the outer tube, one end of the reinforcing layer passes through the outer tube and is connected with the electrode piece, the reinforcing layer and the electrode piece are integrated structure, the electrode ring is against the reinforcing layer and is wrapped to the reinforcing layer, and the electrode ring is electrically connected with the reinforcing layer;The flexible circuit belt is pasted on the outer tube by the adhesive layer.

2. The ablation microcatheter of claim 1, wherein: It further includes connector and connecting pipe, two ends of the connecting pipe are connected with the connector and the base respectively, and one end of the electrode piece is electrically connected with the connector.

3. The ablation microcatheter of claim 1, wherein: The inner tube is provided with a first guide wire cavity, the first guide wire cavity is communicated with the inner cavity, and the base is provided with a perforation away from the inner tube.

4. The ablation microcatheter of claim 1, wherein: The inner tube is provided with a second guide wire cavity, the outer tube is provided with an outer through hole, the inner tube is provided with an inner through hole corresponding to the outer through hole, and the outer through hole is communicated with the second guide wire cavity through the inner through hole.

5. The ablation microcatheter of claim 1, wherein: It further includes support pipe, the support pipe is sleeved outside the inner tube, and the support pipe is used to reinforce the inner tube.

6. The ablation microcatheter of claim 5, wherein: It further includes end head, the end head is connected with the end of the inner tube away from the base, and the hardness of the end of the support pipe close to the end head gradually decreases towards the end head.

7. The ablation microcatheter of claim 6, wherein: The inner tube is provided with a liquid infusion cavity, the liquid infusion cavity is communicated with the inner cavity, and the end head is provided with a liquid outlet hole, and the liquid infusion cavity is communicated with the liquid outlet hole.

8. The ablation microcatheter of claim 6, wherein: The hardness of the end head gradually decreases along the direction away from the inner tube.

9. The ablation microcatheter of claim 1, wherein: The electrode ring includes electrode piece and adhesive layer, the electrode piece includes inner layer and outer layer, the outer layer surrounds the inner layer, the inner layer is connected with the outer layer, the inner layer is electrically connected with the electrode piece, and the outer layer is bonded with the outer tube through the adhesive layer.

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