A balloon electrode assembly and a pulsed electric field ablation catheter

Abstract

This invention relates to balloon catheters, specifically to electrode assemblies for balloon catheters. A balloon electrode assembly, used for point-to-point ablation of focal cardiac lesions, comprises: a balloon body that is inflatable and collapsible, having a proximal and distal end, and an inflated spherical shape; and electrode pads fixed to the balloon body for generating pulsed electric fields. Each electrode pad consists of at least one first electrode pad and at least one second electrode pad, the first electrode pad being offset towards the proximal end of the balloon body, and the second electrode pad being offset towards the distal end of the balloon body. The first and second electrode pads are circumferentially offset, with a second electrode pad positioned between adjacent first electrode pads and a first electrode pad between adjacent second electrode pads, the circumferential direction being the direction of the line connecting the proximal and distal ends of the balloon body. This balloon electrode assembly primarily addresses the problem of improving the ablation efficiency of ablation catheters.

Description

Technical Field

[0001] This invention relates to balloon catheters, and more particularly to electrode assemblies for balloon catheters. Background Technology

[0002] Catheter ablation is a commonly used treatment for arrhythmias. It can cause tissue necrosis through focal ablation, eliminating abnormal electrical discharges in localized tissues. Catheter ablation methods include radiofrequency ablation and pulsed electric field ablation.

[0003] Atrial fibrillation, a type of arrhythmia, is currently treated using pressure-monitored ablation catheters to isolate pulmonary veins point-to-point. Commercially available radiofrequency ablation catheters typically have a simple metal electrode tip, 3.5-4.0 mm in length and 2.33-2.83 mm in diameter. Due to the small size of the electrode tip, the lesion is small, with the ablation area (surface size) at each point being only 2-4 mm. Furthermore, based on the principle of radiofrequency ablation, it relies on heat conduction to achieve ablation, resulting in limited ablation depth. With current technology, isolating a unilateral pulmonary vein requires approximately 30 points, and completing the isolation of one pulmonary vein generally takes 30 minutes, leading to low surgical efficiency.

[0004] Pulsed electric field ablation (PFA), a novel technique for treating atrial fibrillation, involves using a strong electric field to induce irreversible electroporation of cells within a short period. This electroporation-induced cell death has been successfully used as a new non-thermal ablation method for cardiac tissue arrhythmias. Current research on PFA primarily focuses on a "one-shot" design, aiming to create a ring-shaped lesion in a single procedure for rapid isolation of pulmonary veins. However, the pulmonary vein lesions causing atrial fibrillation are complex and diverse, ranging from a common left trunk to multiple small branching vents. One-shot catheters cannot effectively achieve ablation isolation at anatomically varied pulmonary veins. For such cases, point-to-point ablation would be a better solution.

[0005] If a larger point-to-point ablation depth and ablation range can be achieved, the operation time can be greatly shortened and the operation efficiency improved. Summary of the Invention

[0006] This invention provides a balloon electrode assembly and a balloon catheter, which mainly solve the problem of improving the ablation efficiency of ablation catheters.

[0007] In a first aspect, the present invention provides a balloon electrode assembly.

[0008] A balloon electrode assembly is provided for connection to the distal end of an ablation catheter for point-to-point ablation of focal lesions in the heart. The balloon electrode assembly comprises: A capsule that can expand and collapse, the capsule having a proximal end and a distal end, and the expanded capsule having a spherical shape; And electrode plates, which are fixed to the capsule body for generating pulsed electric fields; The electrode pad consists of at least one first electrode pad and at least one second electrode pad, wherein the first electrode pad is biased towards the proximal side of the cyst and the second electrode pad is biased towards the distal side of the cyst. The first electrode and the second electrode are offset circumferentially. In the circumferential direction, a second electrode is provided between two adjacent first electrode pieces, and a first electrode is provided between two adjacent second electrode pieces. The circumferential direction is the direction of the line connecting the proximal and distal ends of the capsule.

[0009] In one technical solution, the capsule has an equatorial position with the largest radial dimension in the inflated state, and the side of the first electrode sheet near the distal end does not exceed the equatorial position; And / or, the side of the second electrode sheet closest to the proximal end does not exceed the equatorial position.

[0010] In one technical solution, the width of the first electrode sheet increases from the proximal end to the distal end, and / or the width of the second electrode sheet increases from the distal end to the proximal end.

[0011] In one technical solution, the edge of the first electrode sheet at the end away from the proximal end is arc-shaped, and / or, the edge of the second electrode sheet at the end away from the distal end is arc-shaped.

[0012] In one technical solution, at least two first electrode sheets and two second electrode sheets are provided; in the circumferential direction, a second electrode sheet is provided between two adjacent first electrode sheets, and a first electrode sheet is provided between two adjacent second electrode sheets.

[0013] In one technical solution, the balloon electrode assembly includes a first trace and a second trace, the first trace being connected to the first electrode sheet, the second trace being connected to the second electrode sheet, and at least a portion of the second trace being arranged side by side with the first electrode sheet along the circumferential direction.

[0014] In one technical solution, the distal end of the capsule does not protrude beyond the spherical surface corresponding to the capsule.

[0015] In one technical solution, the electrode sheet includes a distal electrode disposed at the distal end of the capsule.

[0016] In one technical solution, the distal end of the capsule is provided with a concave structure, and the distal electrode is disposed within the concave structure.

[0017] Secondly, the present invention provides a pulsed electric field ablation catheter.

[0018] Pulsed electric field ablation catheter, including: tube body; And a balloon electrode assembly, which is connected to the distal end of the tube body; The balloon electrode assembly is the balloon electrode assembly described in any of the above technical solutions.

[0019] The beneficial effects of this invention are: According to the aforementioned balloon electrode assembly, the electrodes on the balloon surface are configured to include a first electrode pad biased towards the proximal side and a second electrode pad biased towards the distal side. Since the first and second electrode pads are offset along the balloon's axial direction and arranged in a circumferentially cross pattern, during ablation, depending on the balloon electrode assembly's orientation, the first and second electrode pads can be ablated individually, or simultaneously when the balloon electrode assembly is positioned at its equator against the target tissue, thereby achieving a larger ablation range. Combined with pulsed electric field ablation, which allows for greater ablation depth, a larger ablation lesion can be obtained, thus improving surgical efficiency. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a point-to-point ablation procedure on the heart using an ablation catheter. Figure 2 This is a perspective view of one embodiment of the balloon electrode assembly of the present invention; Figure 3 for Figure 2 Orthographic projection view of the central balloon electrode assembly viewed from the distal end; Figure 4 for Figure 2 Orthographic projection view of the central balloon electrode assembly viewed from the proximal end; Figure 5 for Figure 2 Orthographic projection view of the mid-balloon electrode assembly viewed in a direction perpendicular to the axial direction; List of feature names corresponding to the labels in the figure: 10. Capsule body; 11. Proximal end; 12. Distal end; 13. Equatorial position; 14. Concave structure; 20. Insulating substrate; 21. First electrode plate; 22. Second electrode plate; 31. First trace; 32. Second trace; 40. Distal electrode; 50. Pipe body; 60. Heart; 61. Ablation site. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings. Similar elements in different embodiments are referred to by associated similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of this application. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, certain operations related to this application are not shown or described in the specification. This is to avoid obscuring the core parts of this application with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0022] Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments. At the same time, the steps or actions in the method description can be rearranged or adjusted in a manner obvious to those skilled in the art. Therefore, the various orders in the specification and drawings are only for the clear description of a particular embodiment and do not imply a necessary order, unless otherwise stated that a particular order must be followed.

[0023] The serial numbers assigned to components in this document, such as "first" and "second," are used only to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages).

[0024] The terms "proximal" and "distal" used below are conventional medical terms. For the device to be operated on, the proximal end is the end closer to the operator, and the distal end is the end further away from the operator. For example, in an ablation catheter, the balloon electrode assembly is connected to the distal end of the catheter body.

[0025] The technical solution of this invention can be used for large-area localized ablation catheters, for example... Figure 1 This device can perform point-to-point ablation of focal areas 60 of the heart, forming an ablation focus 61. The balloon electrode assembly of the focal ablation catheter adopts an arrangement where electrode pads are simultaneously distributed at the proximal end 11 and the distal end 12, with the first electrode pad 21 at the proximal end 11 and the second electrode pad 22 at the distal end 12 staggered circumferentially along the balloon electrode assembly. When the balloon electrode assembly is in operation, the first electrode pad 21 and the second electrode pad 22 can each individually contact the tissue to be ablated. When the equatorial position 13 of the balloon electrode is close to the tissue, the first electrode pad 21 and the second electrode pad 22 can also simultaneously contact the tissue to be ablated, thereby forming a larger ablation area (surface size); at the same time, pulsed electric field ablation can be performed by relying on the electrode pads, thereby forming a greater ablation depth.

[0026] Embodiments of the balloon electrode assembly in this invention: Please refer to Figure 1 In one embodiment, the balloon electrode assembly can be used for point-to-point ablation, and is pulsed electric field ablation. Please refer to... Figures 2 to 5 The device includes: a capsule 10, which is expandable and collapseable, having a proximal end 11 and a distal end 12; and electrode plates fixed to the capsule 10 for generating a pulsed electric field; the electrode plates include at least one first electrode plate 21 and at least one second electrode plate 22, the first electrode plate 21 being biased towards the proximal end of the capsule 10 and the second electrode plate 22 being biased towards the distal end of the capsule 10; the first electrode plate and the second electrode plate are offset circumferentially around the capsule 10, the circumferential direction of the capsule 10 being the direction around the line connecting the proximal end 11 and the distal end 12.

[0027] For the balloon electrode assembly, its balloon 10 can be inflated by either gas or liquid; this is not limited in this invention. Furthermore, the balloon 10 can expand and collapse using existing methods, such as by supplying gas or liquid through corresponding channels within the tube 50; these methods will not be described in detail here. It should be noted that the inflated balloon 10 is spherical. In this invention, "spherical" can refer to a standard sphere or other similar spherical shapes, such as an ellipsoid.

[0028] Unlike radiofrequency ablation, which relies on heat conduction, pulsed electric field ablation uses a pulsed electric field as its energy source. The electrode pads fixed to the surface of the balloon electrode assembly's capsule 10 are designed to generate this electric field. The electrode pads can be mounted on an insulating substrate 20 to form a flexible circuit, and then fixed to the capsule 10. To lead out the circuitry of the electrode pads, the flexible circuitry can contain a metal conductor for conducting electrical energy, with the metal conductor forming a trace with the corresponding insulating substrate. In one embodiment, the capsule 10 of the balloon electrode assembly is a small capsule with a diameter of 12 mm, and six bean sprout-shaped flexible circuits are attached to the surface of the capsule 10.

[0029] To achieve the objectives of this invention, please refer to Figure 2 and Figure 5 The first electrode 21 is offset towards the proximal side of the capsule 10, and the second electrode 22 is offset towards the distal side of the capsule 10. It should be noted that the description of being offset towards the proximal side does not imply that the corresponding electrode is entirely located within the hemisphere of the capsule 10 near the proximal end 11. For example, the corresponding electrode may be partially located within the hemisphere of the capsule 10 near the proximal end 11 and partially within the hemisphere of the capsule 10 near the distal end 12. However, overall, the position of the electrode is offset towards the hemispherical boundary of the capsule 10. The description of being offset towards the distal side has a similar explanation and will not be elaborated upon here.

[0030] The aforementioned hemispherical boundary line can be considered as the equatorial position 13 of the cyst 10, that is, the position where the radial dimension of the cyst 10 is largest in its inflated state, and this position surrounds the cyst 10 circumferentially. In one embodiment, please refer to... Figure 2 and Figure 5 The first electrode 21, near the distal end 12, does not extend beyond the equator 13, and the second electrode 22, near the proximal end 11, also does not extend beyond the equator 13. In summary, in one embodiment, the first electrode 21 and the second electrode 22 do not have an overlapping portion along the axial direction of the capsule 10. This structure ensures that when the capsule 10 is tilted axially towards the surface of the tissue to be ablated, the first electrode 21 or the second electrode 22 near the tissue has a larger ablation range, achieving a larger ablation surface area. Of course, in other embodiments, the first electrode 21 and the second electrode 22 may also have an overlapping portion along the axial direction of the capsule 10. For example, the side of the first electrode 21 near the distal end 12 crosses the equator position 13, and the side of the second electrode 22 near the proximal end 11 is flush with the equator position 13 or has a gap between it and the equator position 13.

[0031] To further expand the ablation range, the width of the first electrode 21 increases from the proximal end 11 to the distal end 12, and the width of the second electrode 22 increases from the distal end 12 to the proximal end 11. This increasing width does not necessarily mean that the first electrode 21 as a whole will be smaller at one end and larger at the other, with a gradual change between the two ends; it may only exhibit a change in width in a portion of the area. Please refer to [reference needed]. Figure 2 In one embodiment, the edges of the first electrode 21 at the end furthest from the proximal end 11 and the end closest to the proximal end 11 are arc-shaped, as are the edges of the second electrode 22 at the end furthest from the distal end 12 and the end closest to the distal end 12. Simultaneously, the arc-shaped edges at both ends of the first electrode 21 and the second electrode 22 form a sloping straight edge with a gradually changing width. This variation in width is beneficial for electric field distribution and for achieving a larger ablation range.

[0032] In one embodiment, at least two first electrode plates 21 and two second electrode plates 22 are provided; circumferentially, a second electrode plate 22 is provided between two adjacent first electrode plates 21, and a first electrode plate 21 is provided between two adjacent second electrode plates 22. The aforementioned first electrode plates 21 and second electrode plates 22 form a cross-arrangement structure. Please refer to... Figure 3 and Figure 4In one embodiment, three first electrode pads 21 and three second electrode pads 22 are provided. It should be noted that the number of electrode pads can be determined based on factors such as the diameter of the capsule 10, the ablation requirements, and the area of ​​each electrode pad. The first electrode pad 21 can have the same shape as the second electrode pad 22, such as... Figures 2 to 5 As shown, the first electrode 21 may also have a different shape than the second electrode 22. Additionally, at least two first electrode 21s may have different shapes, and / or at least two second electrode 22s may have different shapes.

[0033] Based on the cross-arrangement structure of the first electrode pad 21 and the second electrode pad 22, in one embodiment, the balloon electrode assembly includes a first trace 31 and a second trace 32. The first trace 31 is connected to the first electrode pad 21, and the second trace 32 is connected to the second electrode pad 22. At least a portion of the second trace 32 is arranged circumferentially alongside the first electrode pad 21. This trace arrangement facilitates the power delivery to the second electrode pad 22 and has an aesthetically pleasing appearance. Preferably, the first trace 31 and the first electrode pad 21 can be centrally aligned, and the second trace 32 and the second electrode pad 22 can be centrally aligned. The proximal end of the trace can be led to the handle of the ablation catheter via a lead wire through the tube body 50 of the ablation catheter.

[0034] When performing ablation with the balloon electrode assembly, if the long axis of the ablation catheter is taken as the axial direction and the surface of the tissue to be ablated is considered as an ideal plane, the mode in which the balloon electrode assembly of the ablation catheter contacts the tissue can be simplified into three forms: the axial direction is perpendicular to the plane, the axial direction is inclined to the plane, and the axial direction is parallel to the plane. In a typical embodiment, the axial direction can be 90°, 45°, and 0° to the plane, respectively. In order to ensure that the electrode pads contact the tissue as much as possible in different modes, in one embodiment, the distal end 12 of the balloon body 10 does not protrude from the spherical surface corresponding to the balloon body 10. That is, the distal end 12 of the balloon body 10 does not have a structure that protrudes from its smooth contour. In this way, the problem of the distal end 12 of the balloon body 10 affecting the posture of the balloon electrode assembly is avoided.

[0035] In one embodiment, to achieve more ablation functions, the electrode sheet includes a distal electrode 40 disposed at the distal end 12 of the capsule 10. The distal electrode 40 forms a distal cap that can close the opening formed at the distal end 12 after the capsule 10 is formed. The distal cap can be made of a metal electrode, forming the distal electrode 40, and is electrically connected by a separate lead that can pass through the interior of the capsule 10. Specifically, the distal electrode 40 can be made of 316 stainless steel or a platinum-iridium alloy. Of course, in other embodiments, the distal end 12 of the capsule 10 can also be provided as an insulating structure, for example, sealed with epoxy resin or other plastic injection molded parts.

[0036] To avoid the distal electrode 40 forming a protruding structure at the distal end 12 of the capsule 10, further, in one embodiment, please refer to... Figure 3 The distal end 12 of the capsule 10 is provided with a concave structure 14, and the distal electrode 40 is disposed in the concave structure 14.

[0037] When the balloon electrode assembly is in operation, it is connected to the distal end 12 of the catheter and inserted into the body through the sheath. For lesions requiring ablation, the posture of the balloon electrode assembly can be adjusted by controlling the curvature of the catheter, allowing the balloon electrode assembly to adhere to the tissue at different angles, and then pulsed electric field ablation is performed using the corresponding electrode pads. Because the balloon electrode assembly of this invention can achieve a larger ablation range and depth, it helps to reduce the number of ablation lesions 61 on the heart 60, thereby improving surgical efficiency, reducing patient suffering, and reducing the surgeon's workload.

[0038] Examples of pulsed electric field ablation catheters in this invention: Pulsed electric field ablation catheter, including: Tube body 50; And a balloon electrode assembly, which is connected to the distal end 12 of the tube body 50; The structure of the balloon electrode assembly is the same as that of the balloon electrode assembly in the above-described embodiments, and will not be described again here.

[0039] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. A balloon electrode assembly, characterized in that, The balloon electrode assembly is used to connect to the distal end of the ablation catheter for point-to-point ablation of focal lesions in the heart. The balloon electrode assembly includes: A capsule, which is expandable and collapseable, having a proximal end and a distal end, and having a spherical shape after expansion; And electrode plates, which are fixed to the capsule body for generating a pulsed electric field; the electrode plates consist of at least one first electrode plate and at least one second electrode plate, the first electrode plate being biased towards the proximal side of the capsule body and the second electrode plate being biased towards the distal side of the capsule body; The capsule has an equatorial position with the largest radial dimension in the inflated state. The proximal end of the first electrode is located at the proximal position of the capsule, and the distal end of the first electrode is located at the equatorial position. The proximal end of the second electrode is located at the equatorial position, and the distal end of the second electrode is located at the distal position of the capsule. The width of the first electrode plate increases from the proximal end to the distal end, and the width of the second electrode plate increases from the distal end to the proximal end. The first electrode and the second electrode are offset circumferentially. In the circumferential direction, a second electrode is provided between two adjacent first electrode pieces, and a first electrode is provided between two adjacent second electrode pieces. The circumferential direction is the direction of the line connecting the proximal and distal ends of the capsule.

2. The balloon electrode assembly as described in claim 1, characterized in that, The side of the first electrode plate closest to the distal end does not exceed the equatorial position; And / or, the side of the second electrode sheet closest to the proximal end does not exceed the equatorial position.

3. The balloon electrode assembly as described in any one of claims 1 to 2, characterized in that, The edge of the first electrode sheet at the end furthest from the proximal end is arc-shaped, and / or the edge of the second electrode sheet at the end furthest from the distal end is arc-shaped.

4. The balloon electrode assembly as described in any one of claims 1 to 2, characterized in that, The first electrode sheet and the second electrode sheet are each provided with at least two.

5. The balloon electrode assembly as described in any one of claims 1 to 2, characterized in that, The balloon electrode assembly includes a first thread and a second thread, the first thread being connected to the first electrode sheet, the second thread being connected to the second electrode sheet, and at least a portion of the second thread being arranged alongside the first electrode sheet along the circumferential direction.

6. The balloon electrode assembly as described in any one of claims 1 to 2, characterized in that, The distal end of the capsule does not protrude beyond the spherical surface corresponding to the capsule.

7. The balloon electrode assembly as described in claim 6, characterized in that, The electrode sheet includes a distal electrode disposed at the distal end of the bladder.

8. The balloon electrode assembly as described in claim 7, characterized in that, The distal end of the capsule has a concave structure, and the distal electrode is disposed within the concave structure.

9. A pulsed electric field ablation catheter, characterized in that, include: tube body; And a balloon electrode assembly, which is connected to the distal end of the tube body; The balloon electrode assembly is the balloon electrode assembly according to any one of claims 1 to 8.

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