A catheter equipped with multiple electrically asymmetrical but physically symmetrical ablation electrodes.

Abstract

To provide a catheter.SOLUTION: The catheter includes a shaft, a distal-end assembly, and a plurality of electrodes mounted on the distal-end assembly. The shaft is configured for insertion into an organ of a patient. The distal-end assembly is coupled to a distal end of the shaft and configured to contact tissue in the organ. At least one of the electrodes is (i) electrically exposed on at least a portion of a surface of the electrode that contact the tissue and (ii) electrically insulated on at least a portion of the surface of the electrode that faces away from the tissue.SELECTED DRAWING: Figure 1

Description

Technical Field

[0003]

[0001] The present invention generally relates to medical probes, and more particularly to multi - electrode catheters.

Background Art

[0002] Various known catheter designs have been proposed in the patent literature. For example, U.S. Patent No. 10,806,511 describes a partially insulated focused ablation (PIFA) tip electrode catheter. These catheters use a thermally conductive material with differential radio - frequency (RF) heating, which enables the application of RF in response to the requirement of delivering RF energy in unipolar mode. Open - irrigation 4 - mm and 8 - mm RF ablation catheters are partially insulated by coating half of their surface with a layer made of vinyl, silicone, vinyl - silicone, polyurethane, or a composite of aluminum oxide / boron nitride (AOBN). RF ablation using a catheter tip partially coated with a thermally conductive insulating material such as AOBN results in a larger ablation lesion volume without the limitations of standard temperature control. The partial insulation of the catheter tip can protect adjacent vital structures during ablation in vivo.

[0003] As another example, U.S. Patent Application Publication No. 2001 / 0018585 describes the release of urethral obstruction achieved by thermal ablation of prostatic tissue by passing an ablation tip electrode into the urethra to the location of the prostate near the point of urethral obstruction. The electrode is connected to a high-frequency power supply to heat the urethra and the prostatic tissue near the urethra to a degree sufficient to ablate it. Image guidance for electrode placement is monitored by an imaging device. The tissue temperature is sensed by the electrode to control the high-frequency heating energy and the ablation process. The electrode has a blunt tip to help prevent irritation to the urethral wall while inserting the electrode into the urethra through the penis and positioning the electrode tip near the point of urethral obstruction. Several forms of electrodes, apparatus, and methods are adapted for specific purposes. [Overview of the project] [Means for solving the problem]

[0004] Embodiments of the present invention described herein provide a catheter comprising a shaft, a distal end assembly, and a plurality of electrodes mounted on the distal end assembly. The shaft is configured for insertion into a patient's organ. The distal end assembly is connected to the distal end of the shaft and is configured to contact tissue within the organ. At least one of the plurality of electrodes is electrically exposed on at least a portion of the surface of the electrode that is in contact with the tissue, and (ii) electrically insulated on at least a portion of the surface of the electrode facing away from the tissue.

[0005] In some embodiments, the electrode is mounted on an arm of the distal end assembly and is mechanically symmetrical with respect to a 180-degree rotation about the longitudinal axis of the arm.

[0006] In some embodiments, the distal end assembly, upon contact with tissue, defines an internal volume enclosed by electrodes, wherein (i) at least a portion of the electrode surface facing the outside of the internal volume is electrically exposed, and (ii) at least a portion of the electrode surface facing the inside of the internal volume is electrically insulated.

[0007] In one embodiment, the distal end assembly is a basket comprising a plurality of extendable arms. In another embodiment, the distal end assembly comprises a helical body. In some embodiments, the distal end assembly comprises a plurality of open-end arms extending from the distal end of the shaft.

[0008] In some embodiments, the electrodes are made from a flexible printed circuit board (PCB) on which an electrical insulator is used.

[0009] According to embodiments of the present invention, a method for manufacturing a catheter is provided, comprising attaching a plurality of electrodes to a distal end assembly configured to contact tissue in a patient's organ, wherein at least one of the plurality of electrodes is (i) electrically exposed on at least a portion of the surface of the electrode in contact with the tissue, and (ii) electrically insulated on at least a portion of the surface of the electrode facing away from the tissue. The distal end assembly is connected to the distal end of a shaft. The present invention will be more fully understood by considering the following “Modes for Carrying Out the Invention” in conjunction with the drawings. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram of a catheter-based cardiac mapping and ablation system, comprising a basket-type catheter, according to an embodiment of the present invention. [Figure 2] Figure 1 is a schematic diagram of a basket-type catheter with asymmetrically electrically insulated electrodes attached, according to an embodiment of the present invention. [Figure 3A]This is a schematic diagram of a Lasso® distal end assembly, to which asymmetrically electrically insulated electrodes are attached, according to an embodiment of the present invention. [Figure 3B] This is a schematic diagram of a multi-arm type Pentaray® distal end assembly, to which asymmetrically electrically insulated electrodes are attached, according to an embodiment of the present invention. [Figure 4] This flowchart schematically illustrates a method for manufacturing a multi-electrode catheter with asymmetrically electrically insulated electrodes, according to an embodiment of the present invention. [Modes for carrying out the invention]

[0011] Overview Multi-electrode catheters, such as basket catheters, are typically fitted with electrodes that, when in contact with tissue, can be used to ablate the tissue and / or to electrophysiologically (EP) map the tissue. However, during ablation and / or EP mapping, the electrodes also come into contact with the blood pool (e.g., the ventricular blood pool). In the case of ablation, the applied electrical energy is also dissipated into the blood. For example, in bipolar ablation, as is commonly done in irreversible electroporation (IRE), there may be excessive electrical conduction through the blood, which can reduce the efficiency of the ablation. Blood dissipation is even more problematic, for example, because it can lead to the formation of blood clots.

[0012] As another example, when performing bipolar EP mapping, electrodes can be affected by interference from far-field signals transmitted through the blood.

[0013] In this context, a bipolar signal is a signal obtained by a pair of electrodes on a catheter. A far-field bioelectrical signal is a signal from a region distant from the tissue area in contact. Typically, such far-field bioelectrical signals propagate through conduction via the blood.

[0014] Blood dissipation and / or long-range field propagation can be reduced by constructing electrodes to have a smaller surface area in contact with the blood, i.e., to be asymmetrical, but the production of such asymmetric electrodes is expensive.

[0015] Some embodiments of the present invention described herein provide a catheter for insertion into an organ such as a patient's heart, comprising a mechanically symmetrical electrode that is therefore inexpensive to produce.

[0016] In the embodiment, the catheter comprises a shaft for insertion into a patient's organ and a distal end assembly connected to the distal end of the shaft, the distal end assembly configured to contact tissue within the organ. Multiple electrodes are mounted on the distal end assembly, and at least one of the electrodes is electrically exposed on at least a portion of the surface of the electrode that is in contact with tissue, and (ii) electrically insulated on at least a portion of the surface of the electrode facing away from the tissue. For this purpose, the electrodes are mounted on an arm of the distal end assembly and are mechanically symmetrical with respect to a 180-degree rotation about the longitudinal axis of the arm.

[0017] When the distal end assembly comes into contact with tissue, it defines an internal volume surrounded by electrodes, the electrodes being (i) electrically exposed on at least a portion of the surface of the electrodes facing the outside of the internal volume, and (ii) electrically insulated on at least a portion of the surface of the electrodes facing the inside of the internal volume.

[0018] To provide the necessary electrical asymmetry and, for example, to form electrodes that carry basket-type catheters, an insulator such as polyurethane coats the "inside" side of the electrode, meaning the sides of the electrode face away from the tissue. In the case of basket-type catheters, the insulating portion faces the internal volume defined by the basket. The uncoated outer surface of the electrode is capable of delivering electrical energy to the contacted tissue.

[0019] The disclosed techniques are applicable to various catheter geometries, for example, a multi-electrode Lasso® catheter (i.e., having a helical distal end assembly) or a Pentaray® catheter (i.e., having a multi-wire distal end assembly with open-ended arms extending from the distal end of the shaft). The plurality of electrodes disposed on one or more arms (e.g., spines) of such a catheter have a geometry that defines a direction away from the tissue for each electrode, as shown below.

[0020] In addition to improving bipolar ablation, the disclosed catheter provides improved EP sensing because it has asymmetric electrodes that generate little electrical signal in the far field.

[0021] By providing a catheter with electrically asymmetric electrodes, cardiac ablation and / or sensing can be made more effective.

[0022] Description of the System FIG. 1 is a schematic depiction of a catheter-based cardiac mapping and ablation system 20 including a basket catheter 40 according to an embodiment of the present invention. System 20 includes a catheter 21 having a shaft 22 that is navigated by a physician 30 to the heart 26 of a patient 28 lying supine on a table 29. In the depicted example, physician 30 uses a manipulator 32 near the proximal end of the catheter and / or near the deflection from sheath 23 to operate the distal end of shaft 22 while inserting shaft 22 through sheath 23. As shown in the inset 25, basket catheter 40 is attached to the distal end of shaft 22. Basket catheter 40 includes a plurality of expandable arms and is inserted from sheath 23 in a folded state and then expanded inside heart 26.

[0023] In an embodiment, the basket catheter 40 is configured to (i) perform spatial mapping of the ventricles of the heart 26 to acquire electrophysiological signals from the ventricular surface 50, and (ii) apply electroablation energy to the ventricular surface 50. An enlarged view of a portion of the inset 25 in FIG. 1 shows the basket catheter 40 within the ventricle of the heart 26. As can be seen, the basket catheter 40 includes an array 48 of electrodes that are connected on a spine forming a basket shape. In one embodiment, ablation is performed in a bipolar ablation mode by applying ablation energy between pairs of electrodes 48.

[0024] The proximal end of the catheter 21 is connected to the console 24. The console 24 comprises a general-purpose computer with a suitable front-end and interface circuit 38 for transmitting and receiving electrical signals that typically enter and exit the catheter 21, as well as for controlling other components of the system 20. In an embodiment, the surface of the surrounding anatomical structure is shown to the physician 30 on the monitor 27, for example, in the graph format of the mesh diagram 35.

[0025] The processor 41 is programmed with software to perform the functions described herein. This software can be downloaded electronically to a computer, for example, over a network, or alternatively or additionally, can be provided and / or stored on a non-transitory tangible medium such as magnetic memory, optical memory, or electronic memory.

[0026] The embodiment depicted in FIG. 1 specifically relates to the use of a basket catheter for cardiac mapping, but other distal end assemblies can be used, such as the helical Lasso® catheter or the multi-arm Pentaray® catheter described above.

[0027] Electrically asymmetric physically symmetric ablation electrodes Figure 2 is a schematic diagram of the basket-type catheter 40 of Figure 1, with an asymmetrically electrically insulated electrode 48 attached, according to an embodiment of the present invention.

[0028] As can be seen, the distal end assembly, in the form of an expandable frame, is connected to the distal end of the shaft 22, and the expandable frame comprises a plurality of expandable spines 52 that define an internal lumen 54, such as one defined by a rotating surface about the longitudinal axis of the shaft 22. However, the internal lumen does not generally need to have rotational symmetry.

[0029] In the shown embodiment, at least a portion of the expandable spine 52 is fabricated from a flexible printed circuit board (PCB).

[0030] Figure 2 shows multiple electrodes 48 mounted on a spine 52. The inner portion of each electrode 48 is coated with a layer of electrical insulator 55. Inset 225 of Figure 2 shows an example of an electrode 48, with its metal portion facing the tissue 50 and its electrical insulating (55) portion facing the blood. The insulating portion 55 may include, for example, polyurethane or any other suitable electrical insulating material. Longitudinal holes through the electrodes are also visible for screwing the electrodes onto the spine 52.

[0031] In this example, the electrode 48 has a circular (or cylindrical) cross-section that is rotationally symmetrical about the longitudinal axis of the spine 52. However, sufficient rotational symmetry is not generally required. In alternative embodiments, the electrode 48 may be symmetrical, for example, with respect to a 180-degree rotation about the longitudinal axis of the spine.

[0032] When catheter 40 is administered to ablate tissue and / or to acquire a diagnostic EP signal from the tissue, electrode 48 comes into contact with both the tissue and the blood. However, the asymmetrical electrical insulation portion 55 reduces some of the applied and / or acquired electrical signals that reach through the blood.

[0033] Figures 3A and 3 are schematic diagrams of Lasso® and multi-arm Pentaray® distal end assemblies 42 and 43, respectively, which are fitted with asymmetrically electrically insulated electrodes 248 and 258, respectively, according to embodiments of the present invention.

[0034] As can be seen in Figure 3A, the helical distal end assembly 42 defines a radius of rotation along the longitudinal axis parallel to the distal end of the shaft 22, and for each electrode 248, it is possible to pre-define an inward radial direction 257 (exemplified by arrow 257) toward the longitudinal axis. As can be seen further, each electrode 248 is asymmetrically electrically insulated in at least a portion of the electrode along the pre-defined direction 257 (255).

[0035] As can be seen in Figure 3B, the distal end assembly 43 pre-defines the proximal direction 260 (illustrated by arrow 260). Furthermore, each electrode 258 is asymmetrically electrically insulated (265) at least on the proximal portion of the electrode along the pre-defined direction 260. Thus, when the distal end assembly 43 pushes tissue distally, its electrodes 258 are in almost complete electrical contact with the tissue, while their proximal portions are electrically insulated from the blood pool.

[0036] Method for manufacturing a catheter with multiple electrically asymmetric electrodes Figure 4 is a flowchart illustrating a schematic method for manufacturing a multi-electrode catheter with asymmetrically electrically insulated electrodes according to an embodiment of the present invention. For the sake of simplicity, manufacturing steps preceding the disclosed manufacturing steps are not shown.

[0037] In the asymmetric electrical insulation process 70, the electrode portion is treated (e.g., by coating or deposition) to have an electrical insulating layer on a portion of its surface, as shown in Figures 2 and 3, for example. Next, in the electrode assembly process 72, the electrode is mounted on the spine 52 of the basket catheter 40 to a distal end assembly such as electrode 48. The electrode is mounted such that when the catheter engages with tissue, the electrically insulated portion faces away from the tissue (i.e., in the inward direction in the case of the basket catheter 40). In the manufacturing process 74, the catheter is completed to have a ready catheter (e.g., attached with wires and mechanically locked).

[0038] The illustrative flowchart shown in Figure 4 is chosen solely for the purpose of clarifying the concept. In practice, the manufacturing steps and methods may differ substantially from those presented in this highly simplified flowchart. For example, electrodes may be manufactured and electrically insulated using a variety of materials and processing methods.

[0039] While the embodiments described herein primarily address cardiac catheterization, the methods and systems described herein can also be used for other applications, such as in neurology, ophthalmology, and renal nerve ablation.

[0040] Accordingly, it will be understood that the embodiments described above are illustrative and not limited to those specifically shown and described above. Rather, the scope of the present invention includes both combinations and partial combinations of the various features described above, as well as variations and modifications thereof not disclosed in the prior art, which would be conceivable to those skilled in the art by reading the foregoing description. Documents incorporated by reference in this patent application shall be deemed to be part of this application, except that, to the extent that any term is defined in such incorporated documents in a manner that contradicts the definitions expressed or implied herein, only the definitions herein shall be considered.

[0041] [Implementation Method] (1) A shaft to be inserted into the patient's organ, A distal end assembly is connected to the distal end of the shaft and configured to contact the tissue within the organ, A plurality of electrodes mounted on the distal end assembly, wherein each of the electrodes is (i) electrically exposed on at least a portion of the surface of the electrode that is in contact with the tissue, and (ii) electrically insulated on at least a portion of the surface of the electrode that is facing away from the tissue. A catheter equipped with [a specific feature / equipment]. (2) The catheter according to Embodiment 1, wherein the electrode is attached to an arm of the distal end assembly and is mechanically symmetrical with respect to a 180-degree rotation about the longitudinal axis of the arm. (3) The catheter according to Embodiment 1, wherein when the distal end assembly comes into contact with the tissue, it defines an internal volume surrounded by the electrodes, and each of the electrodes is (i) electrically exposed on at least a portion of the surface of the electrode facing the outside of the internal volume, and (ii) electrically insulated on at least a portion of the surface of the electrode facing the inside of the internal volume. (4) The catheter according to Embodiment 1, wherein the distal end assembly is a basket having a plurality of extendable arms. (5) The catheter according to Embodiment 1, wherein the distal end assembly includes a helical member.

[0042] (6) The catheter according to Embodiment 1, wherein the distal end assembly comprises a plurality of open end arms extending from the distal end of the shaft. (7) The catheter according to Embodiment 1, wherein the electrodes are arranged on a flexible printed circuit board (PCB) using an electrical insulator. (8) A method for manufacturing a catheter, A plurality of electrodes are attached to a distal end assembly configured to contact tissue in a patient's organ, wherein at least one of the plurality of electrodes is (i) electrically exposed on at least a portion of the surface of the electrode that is in contact with the tissue, and (ii) electrically insulated on at least a portion of the surface of the electrode facing away from the tissue. The distal end assembly is connected to the distal end of the shaft. Methods that include... (9) The method according to embodiment 8, wherein the electrode is attached to an arm of the distal end assembly and is mechanically symmetrical with respect to a 180-degree rotation about the longitudinal axis of the arm. (10) The method of Embodiment 8, wherein mounting the electrodes includes mounting the electrodes to a basket-shaped distal end assembly having a plurality of extendable arms.

[0043] (11) The method according to Embodiment 8, wherein mounting the electrode includes mounting the electrode to a helical distal end assembly. (12) The method according to Embodiment 8, wherein attaching the electrodes includes attaching the electrodes to a plurality of open-end arms extending from the distal end of the shaft. (13) The method according to embodiment 8, wherein the electrodes are made from a flexible printed circuit board (PCB) on which an electrical insulator is used.

Claims

1. A shaft to be inserted into the patient's organs, A distal end assembly is connected to the distal end of the shaft, has an arm, and is configured to contact the tissue within the organ, A plurality of electrodes mounted on the arm of the distal end assembly, wherein each of the electrodes is (i) electrically exposed on at least a portion of the surface of the electrode that is in contact with the tissue, and (ii) electrically insulated on at least a portion of the surface of the electrode that is facing away from the tissue. A catheter comprising, The electrode has a cylindrical shape with a hole extending in the longitudinal direction, and the arm extends through the hole in the electrode so that the electrode is mounted on the outside of the arm. A catheter in which, when the distal end assembly comes into contact with the tissue, it defines an internal volume surrounded by the electrodes, and each of the electrodes is (i) electrically exposed on a first side of the electrode facing the outside of the internal volume, and (ii) electrically insulated on a second side of the electrode facing the internal volume.

2. The catheter according to claim 1, wherein the electrode is mechanically symmetrical with respect to a 180-degree rotation about the longitudinal axis of the arm.

3. The catheter according to claim 1, wherein the distal end assembly is a basket having a plurality of expandable arms.

4. The catheter according to claim 1, wherein the distal end assembly includes a helical member.

5. The catheter according to claim 1, wherein the distal end assembly comprises a plurality of open end arms extending from the distal end of the shaft.

6. The catheter according to claim 1, wherein the electrodes are arranged on a flexible printed circuit board (PCB) using an electrical insulator.

7. A method for manufacturing a catheter, A plurality of electrodes are attached to a distal end assembly configured to contact tissue in a patient's organ, wherein at least one of the plurality of electrodes is (i) electrically exposed on at least a portion of the surface of the electrode that is in contact with the tissue, and (ii) electrically insulated on at least a portion of the surface of the electrode facing away from the tissue. The distal end assembly is connected to the distal end of the shaft. Includes, The distal end assembly has an arm, and the electrode is mounted on the arm. The electrode has a cylindrical shape with a hole extending in the longitudinal direction, and the arm extends through the hole in the electrode so that the electrode is mounted on the outside of the arm. A method wherein, when the distal end assembly comes into contact with the tissue, it defines an internal volume surrounded by the electrodes, and each of the electrodes is (i) electrically exposed on a first side of the electrode facing the outside of the internal volume, and (ii) electrically insulated on a second side of the electrode facing the internal volume.

8. The method according to claim 7, wherein the electrode is mechanically symmetrical with respect to a 180-degree rotation about the longitudinal axis of the arm.

9. The method according to claim 7, wherein mounting the electrodes includes mounting the electrodes to a basket-shaped distal end assembly having a plurality of extendable arms.

10. The method according to claim 7, wherein attaching the electrode includes attaching the electrode to a helical distal end assembly.

11. The method according to claim 7, wherein attaching the electrodes includes attaching the electrodes to a plurality of open-end arms extending from the distal end of the shaft.

12. The method according to claim 7, wherein the electrodes are made from a flexible printed circuit board (PCB) on which an electrical insulator is used.

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