CN220109803U - Unidirectional impact waveguide tube - Google Patents

Abstract

The present disclosure provides a unidirectional impact waveguide. The catheter includes: a front end assembly and an operating assembly, the front end assembly comprising an outer layer and an inner assembly, the inner assembly being connected to the outer layer at a distal end of the front end assembly and forming a chamber between the inner assembly and the outer layer capable of containing a conductive solution; the front end assembly further comprises a first electrode arranged to surround the inner assembly and a second electrode arranged to surround the first electrode, the first electrode and the second electrode being both between the outer layer and the inner assembly, wherein the first electrode and the second electrode are electrically connected with the first electrode wire and the second electrode wire, respectively, the first electrode and the second electrode form a gap at the distal end, the second electrode is expanded towards the distal end in the axial direction of the catheter and forms a guiding structure, and the operating assembly is arranged to be connected with the front end assembly through a connecting tube. The catheter of the present disclosure has the advantage of smaller profile dimensions and more concentrated unidirectional transmitted shock waves than conventional shock wave generating devices.

Description

Unidirectional impact waveguide tube

Technical Field

The present disclosure relates to the technical field of medical devices, and in particular, to a unidirectional impact waveguide.

Background

In general, calcified lesions in blood vessels or other obstructions in blood vessels, are involved in arteriosclerosis, kidney stones, etc. For example, atherosclerosis (AS) is a major cause of coronary heart disease, cerebral infarction, peripheral vascular disease. Lipid metabolism disorder is the pathological basis of atherosclerosis, and is characterized in that affected arterial lesions begin from intima, generally have accumulation of lipid and complex carbohydrate, bleeding and thrombosis, fibrous tissue hyperplasia and calcareous deposition, and gradual disintegration and calcification of middle layers of arteries, which lead to thickening and hardening of arterial walls and stenosis of vascular cavities. Lesions often involve large and medium muscle arteries, once developed enough to occlude the lumen of the artery, the tissue or organ supplied by the artery will be ischemic or necrotic. The appearance of lipid accumulated in the intima of an artery is yellow, and is therefore known as atherosclerosis.

In particular, atherosclerosis, the majority of which is free of specific severe symptoms. The expansion of the aortic voiced sound region behind the sternum can be found during the percussion; the second heart sound in the aortic valve region is in turn metallic tone and has systolic murmurs. The systolic blood pressure is increased, the pulse pressure is widened, and palpation of the radial artery can be similar to pulse promotion. The common X-ray examination shows that the aortic knots bulge upward and leftward, and that the aortic dilation and tortuosity, and sometimes the plaque-like or arc-like calcareous deposit shadows. Aortic atherosclerosis can also form aortic aneurysms, most commonly occurring at the abdominal aorta below the renal artery ostia, followed by the aortic arch and descending aorta. The rumen of the abdominal aorta is mostly found due to pulsating mass swelling of the abdomen during physical examination, and the corresponding part on the abdominal wall can hear murmurs.

In addition, renal atherosclerosis is a part of systemic atherosclerosis, but is not necessarily parallel to the severity of systemic atherosclerosis, is clinically common to elderly people over 60 years old, has no obvious clinical symptoms, has few other abnormal changes except for some patients with trace proteinuria, and can cause arterial embolism, appear as renal insufficiency and even develop into uremia in a stress state. This condition may be accompanied by arteriosclerosis of other organs, such as heart, brain or fundus changes, with corresponding clinical manifestations. The disease can be classified into benign arteriolar nephrosclerosis and malignant renal arteriolar arteriosclerosis. The treatment is to reduce blood pressure, blood lipid, delay or reduce the development of arteriolar nephrosclerosis in order to avoid renal insufficiency, hereinafter mainly described as benign arteriolar nephrosclerosis, generally referred to as hypertension benign arteriosclerotic disease.

Currently, guidewire solutions exist for the above-mentioned conditions that utilize radiofrequency energy to open an occlusion. However, puncturing the occlusion by radio frequency energy creates strong hot spots, which in turn damage the artery or vessel wall. And, the rf energy generates a plasma that burns any material in its path. Thus, such devices must be used with great care and must be moved continuously without stopping somewhere to avoid damaging the artery or vessel. Furthermore, this treatment regimen requires a centering mechanism that keeps the plasma centered in the artery or vessel. Such centering, especially at the corners and bends of arteries or veins, is difficult to achieve from the current technology.

Thus, the use of shock waves of a common scale between electrodes for clearing vascular occlusions is also mentioned. However, in the case of severe calcified lesions, the need for diagnosis or passage of a stenosis or partial diameter is too small, which may result in the inability of the normal gauge shock wave lithotripsy balloon catheter to pass, and thus in the failure to diagnose. How to provide a shockwave device for generating a positive shockwave to sufficiently flush open a fully occluded blood vessel to allow delivery of a device therethrough such as a guidewire and an angioplasty balloon is a problem to be solved. Further, how to further improve the efficiency of radiating shock wave energy of a higher scale only in the target direction in the blood vessel by arranging the shock wave device structure in order to optimize the shock wave of a specific discharge direction under the condition of the existing external input power scale, that is, improving the concentration of shock waves in the discharge direction, is a technical problem to be solved.

Disclosure of Invention

To address at least one of the above problems, as well as one or more of other potential problems, the present disclosure proposes a unidirectional impact waveguide.

In a first aspect of the present disclosure, there is provided a unidirectional impact waveguide comprising: a front end assembly and an operating assembly, wherein the front end assembly is capable of extending into a lumen of a blood vessel, and the front end assembly comprises an outer layer and an inner assembly, the inner assembly being connected to the outer layer at a distal end of the front end assembly, and the inner assembly and the outer layer forming a chamber therebetween capable of containing a conductive solution; the front end assembly further comprises a first electrode arranged to surround the inner assembly and a second electrode arranged to surround the first electrode, the first electrode and the second electrode each being located between the outer layer and the inner assembly, wherein the first electrode and the second electrode are electrically connected to a first electrode wire and a second electrode wire, respectively, the first electrode and the second electrode form a gap at a distal end, the second electrode extends distally in an axial direction of the catheter and forms a guiding structure, the operating assembly is arranged to be connected to the front end assembly by a connecting tube.

Further, the outer layer includes an inflatable balloon.

Further, a first insulating protective layer is provided between the first electrode and the second electrode.

Further, the outer surface of the second electrode is provided with a second insulating protective layer.

Further, the inner member is configured as a double-layered inner tube distally connected to the outer layer.

Further, the double-layered inner tube is configured as a tube body having an inner lumen configured to receive a guidewire.

Further, the double-layered inner tube is configured to extend from the distal end up to the proximal end of the catheter and to communicate with the proximal handle infusion channel.

Further, the second electrode is formed in a tubular structure surrounding the inner member by expanding and extending distally in the axial direction of the catheter, and the second electrode is formed in an open structure by expanding and expanding distally in the axial direction of the catheter.

Further, the second electrode includes a first tubular section and a second tubular section, the first tubular section and the second tubular section are continuously connected, and a diameter of the second tubular section extending to an outermost edge is 1.2 to 3 times a diameter of a place where the second tubular section adjoins the first tubular section.

Further, the wall of the expanded side of the second tubular section of the second electrode forms an obtuse angle with the wall of the first tubular section, the obtuse angle being greater than 120 ° and less than 170 °.

Compared with the prior art, the method has the following beneficial effects:

(1) Embedding shock wave generating electrodes within the balloon may help break up plaque, thereby providing a more durable treatment regimen for atherosclerotic disease. The arc discharge across the electrodes causes the bubbles to rapidly expand and collapse, thereby generating a shock wave. The shock wave propagates through the liquid medium in the balloon and strikes the calcified plaque, pulverizing the hard matter. This is beneficial for further interventional procedures such as stent placement in calcified arteries and may also reduce the occurrence of restenosis.

(2) The second electrode (external electrode) is expanded and extended towards the far end along the axial direction of the catheter to form a guide structure, and the guide structure has a gathering effect, so that the catheter generates unidirectional impact waves, the unidirectional impact waves are more concentrated, and a better stone crushing effect is realized. Further, the second electrode is arranged into a first tubular section and a second tubular section, the first tubular section and the second tubular section are continuously connected, the diameter of the second tubular section extending to the end (namely, the position of the outermost edge) is 1.2-3 times of the diameter of the position of the second tubular section adjacent to the first tubular section, and the wall of the expanding edge of the second tubular section forms an obtuse angle with the wall of the first tubular section, the obtuse angle is more than 120 DEG and less than 170 DEG, so that the shock wave generated by the structure in the front end direction is more concentrated, and the intervention size of the whole catheter product can be further reduced.

Drawings

The above and other features, advantages and aspects of embodiments of the present disclosure will become more apparent by reference to the following detailed description when taken in conjunction with the accompanying drawings. In the drawings, wherein like or similar reference numerals denote like or similar elements, in which:

FIG. 1 illustrates a partial schematic view of a portion of an impact waveguide front balloon according to some embodiments of the present disclosure;

FIG. 2 illustrates an overall schematic view of an impact waveguide according to some embodiments of the present disclosure;

FIG. 3 illustrates a schematic perspective view of an impact waveguide according to some embodiments of the present disclosure;

FIG. 4 illustrates a host module schematic diagram according to some embodiments of the present disclosure;

FIG. 5 illustrates a balloon alternate structural schematic according to some embodiments of the present disclosure; and

fig. 6 illustrates an alternative structural schematic of an outer electrode according to some embodiments of the present disclosure.

Detailed Description

Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While certain embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete. It should be understood that the drawings and embodiments of the present disclosure are for illustration purposes only and are not intended to limit the scope of the present disclosure.

In describing embodiments of the present disclosure, the term "comprising" and its like should be taken to be open-ended, i.e., including, but not limited to. The term "based on" should be understood as "based at least in part on". The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The terms "first," "second," and the like, may refer to different or the same object. Other explicit and implicit definitions are also possible below.

Furthermore, it should be noted that in the description of the embodiments of the present utility model, "in vivo" means inside the tissue organ of the patient and "in vitro" means outside the tissue organ of the patient, unless explicitly defined otherwise. Meanwhile, in the embodiment of the present utility model, "distal" means a direction away from a physician, and "proximal" means a direction close to the physician.

In the current art, the use of shock wave assisted balloon angioplasty is one method of treating highly calcified plaque. While conventional balloon angioplasty can expand the lumen space by balloon inflation, it does not improve vascular compliance, and dissection and restenosis are common complications both intra-and post-operatively. Embedding shock wave generating electrodes within the balloon may help break up plaque, thereby providing a more durable treatment regimen for atherosclerotic disease. The arc discharge across the electrodes causes the bubbles to rapidly expand and collapse, thereby generating a shock wave. The shock wave propagates through the liquid medium in the balloon and strikes the calcified plaque, pulverizing the hard matter. This is beneficial for further interventional procedures such as stent placement in calcified arteries and may also reduce the occurrence of restenosis. Therefore, in order to treat atherosclerosis, it is desirable to develop a balloon angioplasty catheter that utilizes shock waves to break down and fragment calcium in the blood vessel. The shock waves are shockable in nature and are capable of striking and breaking down hard calcified platelets deposited on the inner wall of the artery. Once these deposits disintegrate, the space in the arterial lumen expands, improving blood flow. In contrast to conventional balloon angioplasty, in which the lesion is enlarged by mainly pressing on the atheromatous platelets by high pressure machinery, which often causes exfoliation, the purpose of this device is to break down the calcium itself. This may increase the compliance of the vessel and allow the artery to receive further intervention, such as stent placement, or be used alone as a therapeutic means. One example of a shock wave angioplasty catheter may include an elongated collapsible balloon sized to fill the luminal space of an arterial vessel and to physically contact calcified platelets when inflated with a liquid. The balloon may contain a plurality of shock wave sources therein. Shock waves are generated from these shock wave sources when the balloon is inflated within the atherosclerotic region of the artery to rupture the contacted calcium deposits. Arcing between the end faces of the electrodes across the non-conductive gap is the primary mechanism for generating the shockwave. The ionization event across the electrodes in the liquid medium forms a channel through which a large discharge current will pass. The cavitation bubbles produced rapidly expand and collapse, thereby producing an impact shock wave that continues through the liquid medium in the balloon to destroy the calcium. Then, when the common scale shock wave generating device is used, the minimum product outline size can only reach 1.1-1.2mm, and how to further reduce the outline size of the shock wave generating device so as to pass through the calcified narrower blood vessel becomes a problem to be solved. In addition, when the structure of the shock wave device is improved to generate unidirectional shock waves, how to concentrate the unidirectional shock waves more, so as to achieve better stone breaking effect, is also a problem to be solved.

In order to solve at least one of the above problems, and one or more of other potential problems, example embodiments of the present disclosure propose a unidirectional shock waveguide to solve the problem that the profile size of the shock wave device product in the prior art cannot be further reduced, unidirectional shock waves cannot be more concentrated, and then the intractable calcification lesions cannot be crushed.

Fig. 1 illustrates a schematic view of a portion of a single directional impact waveguide front end balloon portion according to some embodiments of the present disclosure. In this example embodiment, the front end assembly of the unidirectional impact waveguide 100 includes an outer layer and an inner assembly connected to the outer layer at the distal end of the catheter 100, and forming a chamber therebetween capable of containing a conductive solution; wherein the outer layer, which may be, for example, a flexible outer tube, comprises a tip 8, which tip 8 is near the distal end, in particular near the connection with the inner component, wherein the tip 8, as it is at the most distal end of the entire catheter 100, and assumes a conical or truncated conical configuration, which acts as a guiding path for the entire catheter 100 in the blood vessel. Further, the outer layer also comprises an expandable balloon 1 tightly attached to the tip 8. In particular, the inflatable balloon 1 may be inflated by pumping additional fluid or solution into the chamber of the shock waveguide 100. In particular, the inflatable balloon 1 may be inflated before or after the application of a shock wave to the target treatment area. Further, the inner assembly may form a double inner tube 7, which double inner tube 7 may be a tube body distally connected to the outer layer and having a lumen capable of receiving a guidewire, preferably a cylindrical elongated tube body, and which double inner tube 7 extends distally to the proximal end of the shock waveguide 100 and communicates with the proximal handle infusion channel 9. Further, in the section of the expandable balloon 1, the outer surface of one of the sections of the double-layered inner tube 7 is covered with an electrode support layer 6 for supporting the inner electrode 5 (or referred to as a first electrode) that is in close proximity to the outer surface of one section of the electrode support layer 6. Further, the outer surface of the inner electrode 5 is provided with an inner electrode insulation protecting sleeve 4 for wrapping the outer surface of the entire inner electrode, and the outer surface of a section of the inner electrode insulation protecting sleeve 4 is provided with an outer electrode 3 (or referred to as a second electrode), and obviously, the inner electrode insulation protecting sleeve 4 can isolate the inner electrode 5 from the outer electrode 3, and can electrically insulate the inner electrode from the outer electrode. Further, the outer surface of the external electrode 3 is provided with an external electrode insulation protective sleeve 2, which plays an insulation protective role on the external electrode. In some embodiments, the arcing across the non-conductive gap between the electrode end faces creates a shockwave, ionization across the electrodes within the liquid medium creates a channel through which large discharge currents will pass, and the cavitation bubbles created expand and collapse rapidly, creating a shockwave that continues through the liquid medium in the balloon to destroy the calcium. In order to further enhance the shock wave in a given direction, the outer electrode 3 is preferably arranged in a tubular structure surrounding the inner assembly by causing the catheter 100 to be more focused in its axial, in particular distally directed, shock wave generating direction, and to expand in an axial direction, in an open-like structure, in particular dividing or configuring the outer electrode 3 into a first tube section, which is a tube section of given inner diameter, and a second tube section, which is distal to the first tube section and is connected to the first tube section by the tube wall, and which, starting from the connection with the first tube section, gradually expands in the axial and distal direction of the catheter (i.e. the inner radial catheter of the second tube section in the extension increases in axial and distal direction with the extension, or increases with the extension and after a certain distance with the given inner diameter, increases with the extension and continues to increase after a certain distance with the given inner diameter), for example as shown in fig. 1. It should be noted that in the above-described embodiment, the outer electrode 3 is provided in a distally overhanging shape, or in a "horn" like shape, which enables the outer electrode 3 of the catheter 100 to discharge forward, opening up calcified lesion tissue in front, and in particular, if no outer electrode 3 is provided in such a distally overhanging shape, the electrode is provided axially, but the discharge in the distal direction (or so-called forward direction) is only partial, and does not effectively concentrate the shock wave that finally goes in the distal direction. Still further, the outer electrode 3 is entirely formed to surround the inner member, and the outer electrode 3 is provided in a shape that is outwardly expanded toward the distal end, for example, it may be that the outer electrode 3 includes a section that is wrapped around the inner member, and includes a distally-projecting section that gradually expands in diameter so that the outer electrode 3 assumes a "horn" shaped structure at that section. Preferably, the outer electrode 3 comprises a first tubular section and a second tubular section, the first and second tubular sections being continuously connected, and the second tubular section extending to the end (i.e. at the outermost edge) having a diameter which is 1.2-3 times, most preferably 1.5 times the diameter of the second tubular section adjoining the first tubular section, and at the same time, if the cross-sectional view of fig. 1 is taken as an example, the wall of the diverging side of the second tubular section of the outer electrode 3 forms an obtuse angle with the wall of the first tubular section, which is more than 120 ° and less than 170 °, most preferably 150 °; the "horn" configuration thus provided greatly concentrates the shock wave energy generated by the catheter 100, and is more conducive to opening the calcified lesion tissue in front. In some embodiments, an outer electrode wire 14 connected to the outer electrode 3 and an inner electrode wire 15 connected to the inner electrode 5 are also provided in the outer layer to supply power to the inner and outer electrodes, respectively.

Fig. 2 illustrates a schematic diagram of a unidirectional impact waveguide overall according to some embodiments of the present disclosure. In this example embodiment, the body portion includes: two parts of the front end assembly and the operating assembly 11. Wherein the front end assembly comprises an expandable balloon 1 at a distal end with respect to the operator, which requires intervention inside the human body with the aid of instruments during use. An operating assembly 11 (e.g., an operating handle) is located at the proximal end, and an operator can control the position of the front end assembly, etc., by operating the assembly 11. For example, the operator may move the position of the front end assembly forward or backward to adjust the position of the ablation assembly within the body. In other embodiments, the operating component 11 may be electrically controlled to control the adjustment of the distal and proximal positions and the adjustment of the posture of the front-end component. To facilitate entry of the front end assembly into the human body, the front end assembly body is spindle-shaped or streamlined, or is shaped as an elongate shaft, or is shaped as an elongate strip. Further, in some embodiments, the front end assembly and the operation assembly 11 may be connected by a connection tube, wherein the connection tube may be sequentially connected with the expandable balloon 1 in a penetrating manner, and a quick-change wire guide interface 13 and a stress expansion tube 12 are sequentially disposed between the expandable balloon 1 and the operation assembly 11, and extend into the operation assembly 11, and extend from a proximal end portion of the operation assembly 11 to be communicated with the handle infusion channel 9. In some alternative embodiments, the operation assembly 11 may be in an electric control manner, and then an electrical interface is further disposed on the operation assembly 11, where the electrical interface is connected with a cable for electrically connecting with the host interface, and the cable is used to transmit a wire signal inside the connection pipe to the control host, so that an operator can conveniently know the working state of the electrode in real time, and adjust the working state appropriately according to the working state. For example, the on-off of the circuit of the electrode and the input power of the electrode can be controlled, and the flow rate of the cooling medium can be adjusted according to the working temperature of the electrode. The control host also comprises a cooling circulation module which can circulate the cooling medium in the connecting pipe. In addition, the control host is also provided with a display module, and based on the received signal data, the display module can display parameter data such as the discharge times, the balloon specification and the like.

Fig. 3 illustrates a schematic perspective view of an impact waveguide according to some embodiments of the present disclosure. In this example embodiment, the inflatable balloon and the connecting tube can be seen to be in an elongated streamlined configuration to facilitate intervention inside the human body.

Fig. 4 illustrates a host module schematic diagram according to some embodiments of the present disclosure. In this example embodiment, the host computer connected to the operation component has a display module, for example, on which data parameters such as the number of discharges, balloon specifications, and the like can be displayed. In addition, the display module comprises a balloon host interface and a trigger switch interface besides the display area. Further, an operator controls the discharge of the electrode in the saccule through a trigger switch connected with the host, and the host is provided with a relevant display screen for displaying the discharge times, and can identify catheters with different specifications so as to control the discharge power and voltage. In addition, the host computer has power-off protection device, prevents that the operator from touching discharge switch by mistake when sacculus breaks, causes the damage to the patient.

Fig. 5 illustrates a balloon alternate structural schematic according to some embodiments of the present disclosure. In this example embodiment, two balloon structures are shown, in other words, the balloon structures may be more elongate fusiform streamline structures on both ends, which are more advantageous for accessing finer vessels or occlusion areas. In some alternative embodiments, the balloon structure may also be a more rounded and plump structure that is more conducive to intervention in relatively large vessels or tissues.

Fig. 6 illustrates an alternative structural schematic of an outer electrode according to some embodiments of the present disclosure. In this example embodiment, four alternative configurations of the outer electrode distal extension are shown. In one embodiment, for example, the distal extension of the outer electrode may be a small, sharply diametrically expanded structure followed by a small, slowly diametrically expanded structure to facilitate the localized propagation of shock waves in the distal direction. In one embodiment, for example, the outer electrode distal extension may be a slowly expanding diameter structure with the expansion forming a flare-like expansion, or a barrel-like expansion, or a cone-like expansion, or a hemispherical expansion to facilitate constraining the concentrated propagation of shock waves in the distal direction. Therefore, when the expansion structure faces a specific direction, the impact waves diffused towards other directions are reflected by the outer electrode wall and are re-gathered, so that loss of original diffusion towards other directions is reduced, the amplitudes of the impact waves are overlapped, the strength of the impact waves is higher, in other words, the horn mouth structure can restrict and strengthen the intensity of the original impact waves propagating towards the specific direction.

In some embodiments, a unidirectional shockwave balloon catheter is provided that includes an expandable balloon at a forward end, an outer electrode having a guiding structure, and a cylindrical inner electrode, and an insulating material coating the electrode. In other embodiments, the catheter has a guide wire channel, and a fluid channel in the middle section. In other embodiments, the catheter has a handle at its rear end for connecting the host port and the fluid port, a stress-expandable tube at its front end for connecting to the middle catheter channel, and a circuit structure for controlling the energizing of the wires in the handle.

The foregoing description of the embodiments of the present disclosure has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the various embodiments described. The terminology used herein was chosen in order to best explain the principles of the embodiments, the practical application, or the technical improvements in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

The foregoing is merely an alternative embodiment of the present disclosure, and is not intended to limit the present disclosure, and various modifications and variations will be apparent to those skilled in the art. Any modifications, equivalent substitutions, improvements, etc. that fall within the spirit and principles of the present disclosure are intended to be included within the scope of the present disclosure.

Claims (10)

1. A unidirectional impact waveguide comprising: a front end assembly and an operating assembly,

it is characterized in that the method comprises the steps of,

the front end assembly is extendable into a vessel lumen and comprises an outer layer and an inner assembly connected to the outer layer at a distal end of the front end assembly and forming a chamber therebetween capable of containing a conductive solution;

the front end assembly further comprising a first electrode disposed around the inner assembly and a second electrode configured around the first electrode, the first electrode and the second electrode each being between the outer layer and the inner assembly, wherein the first electrode and the second electrode are electrically connected to a first electrode wire and a second electrode wire, respectively, the first electrode and the second electrode forming a gap at a distal end, the second electrode extending in an axial direction of the catheter toward the distal end and forming a guiding structure,

the operating assembly is configured to be coupled to the front end assembly via a connecting tube.

2. The catheter of claim 1, wherein the outer layer comprises an expandable balloon.

3. The catheter of claim 1, wherein a first insulating protective layer is disposed between the first electrode and the second electrode.

4. Catheter as claimed in claim 1, characterized in that the outer surface of the second electrode is provided with a second insulating protective layer.

5. The catheter of claim 1, wherein the inner assembly is configured as a double-layered inner tube distally connected to the outer layer.

6. The catheter of claim 5, wherein the double-layered inner tube is configured as a tube having a lumen configured to receive a guidewire.

7. The catheter of claim 5, wherein the double-layered inner tube is configured to extend from a distal end all the way to a proximal end of the catheter and to communicate with a proximal handle infusion channel.

8. The catheter of claim 1, wherein the second electrode is configured to expand distally along the axial direction of the catheter and form a guiding structure, wherein the second electrode is configured to surround the tubular structure of the inner assembly, and wherein the second electrode expands distally along the axial direction of the catheter to form an open structure.

9. The catheter of any one of claims 1-8, wherein the second electrode comprises a first tubular section and a second tubular section, the first tubular section and the second tubular section being continuously connected, and the second tubular section extending to a diameter at an outermost edge that is 1.2-3 times a diameter of the second tubular section adjacent the first tubular section.

10. The catheter of claim 9, wherein the wall of the flared side of the second tubular section of the second electrode forms an obtuse angle with the wall of the first tubular section, the obtuse angle being greater than 120 ° and less than 170 °.