LV flat electrode

Abstract

The present invention provides an electrode useful for treating biological tissue using electric current, in particular an implantable flat electrode (1), the electrode comprising laminated first and second insulating layers (2, 3) comprising an elastic, biocompatible, and biostable material, wherein the second insulating layer (3) has at least one opening (3c), and a flexible conductive material (4) sandwiched between the first and second insulating layers (2, 3), which is embedded in the first insulating layer (2) and covered by the second insulating layer (3). The conductive material (4) comprises a central portion (4b) that is exposed through an edge portion (4a) and at least one opening (3c) of the second insulating layer (3) and is not fixed to the first insulating layer (2); two or more pairs of suture holes (2a, 3a) provided in the peripheral edge portions (2b, 3b) of the first and second insulating layers (2, 3), wherein the edge portions (2b, 3b) are laminated together without the conductive material (4) in between; and an electrical connector (6) electrically coupled to the conductive material (4).

Description

[Technical Field]

[0001] The present invention relates to an electrode, specifically an implantable flat electrode, that is useful for treating biological tissue using electric current, comprising at least two insulating layers, a conductive material, and an electrical connector, as well as a process for manufacturing a flat electrode. [Background technology]

[0002] The first epicardial flat electrodes (sometimes referred to as "patch leads") were commonly used in implantable cardioverter-defibrillators (ICDs), which began in the early 1990s. Typical flat electrodes use silicone as the non-conductive lead component and titanium or platinum alloy as the conductive material. These early electrodes were not designed to accept direct current and typically have an insufficiently small electrically effective surface area.

[0003] Flat electrodes for the treatment of biological tissue are known from International Publication No. 2006 / 106132, U.S. Patent Application Publication No. 2010 / 152864, and International Publication No. 2007 / 070579. International Publication No. 2006 / 106132 describes an electrode for treating biological tissue with direct current. U.S. Patent Application Publication No. 2010 / 152864 describes an implant for use in biological tissue, comprising an electrical stimulation system in which a control unit is suitable for limiting or controlling the current density at the implant-bone interface. International Publication No. 2007 / 070579 describes an implant for stimulating the regeneration of damaged biological tissue, which applies direct current near the site of injury at a level sufficient to induce regeneration without applying a current level that would cause tissue toxicity.

[0004] Such flat electrodes typically contain a silicone material and are attached to the target tissue by suture, clamp, staple, or any other suitable method to ensure close contact with the surface of the target tissue. As fastening means, the flat electrode includes, for example, a suture hole integrated into the silicone material, usually located along the electrode edge, which allows for suturing to the target tissue.

[0005] When silicone sutures are used to fix electrodes, and the silicone material is subjected to excessive tensile load by surgical sutures, the sutures may deform or even completely tear because, although the silicone material is extremely flexible, its tensile strength is only slight. In these cases, the conductive electrode material of the implanted flat electrode may partially or completely detach from the tissue, resulting in an inability to optimally maintain the treatment of the target tissue.

[0006] Flat electrodes for the treatment of biological tissue are typically manufactured by encasing a conductive material in liquid silicone, leaving one side of the conductive material exposed, or by bonding the conductive material to a solid silicone layer with a suitable binder. Both methods produce a flat electrode in which the conductive material is connected to a single silicone layer, which also serves to attach the flat electrode in areas where conductive material is normally absent. Due to the single-layer silicone structure, the portion of the silicone layer used to attach the flat electrode, such as the peripheral region of the flat electrode, has weaknesses in terms of stable and reliable attachment to tissue.

[0007] On the other hand, the conductive portion of a flat electrode should ideally be highly flexible and low in rigidity in order to conform closely to the surface of the target biological tissue, which often has an uneven surface. It has been observed that flat electrodes that are excessively flexible and too rigid, particularly in the surrounding region, may deform and displace after a certain period following implantation. This deformation and displacement can be caused by suture rupture and / or by biological reactions such as fibrosis. Electrode deformation and displacement can limit contact with the target tissue, potentially preventing effective treatment of the organ in question.

[0008] Therefore, a flat electrode is needed that maintains flexibility in the conductive portion of the electrode area so as to conform appropriately to the target organ, while also providing strong reinforcement against tearing and peeling, and increasing the surrounding rigidity to withstand deformation after implantation. [Overview of the project]

[0009] To address the needs described above, the object of the present invention is to provide a flat electrode that has a lower risk of detachment and deformation after implantation and enables effective treatment of the target biological tissue, and to provide a process for manufacturing such a flat electrode.

[0010] In a first aspect of the present invention, a flat electrode comprises: first and second insulating layers laminated together, comprising an elastic, biocompatible, and biostable material, the second insulating layer having at least one opening; a flexible conductive material sandwiched between the first and second insulating layers, comprising an edge portion embedded in the first insulating layer and covered by the second insulating layer, and a central portion exposed through at least one opening in the second insulating layer and not fixed to the first insulating layer, with two or more pairs of suture holes provided in the peripheral edge portions of the first and second insulating layers, the edge portions being laminated together without a conductive material in between; and an electrical connector electrically coupled to the conductive material. This design provides flexibility while improving morphological stability against deformation as a result of bodily response and offers enhanced fastening means to prevent long-term migration of the electrode. This enhances the effectiveness and safety of treating biological tissue with electric current.

[0011] According to one embodiment of the first aspect, the conductive material includes a metal mesh, which preferably includes platinum, more preferably a platinum-iridium alloy. The platinum-iridium alloy preferably has a platinum-iridium alloy ratio of 70:30 to 99:1, more preferably 80:20 to 95:15, and most preferably 88:12 to 92:8.

[0012] According to yet another embodiment of the first aspect, the conductive material has a constricted shape in plan view, comprising two distal portions connected by a constricted portion in its longitudinal direction, wherein the ratio of the width of the distal portions perpendicular to the longitudinal direction to the constricted portion is 1.5:1 to 7:1, preferably 2:1 to 6:1, and more preferably 3:1 to 5:1.

[0013] According to yet another embodiment of the first aspect, the flat electrode comprises a frame positioned between first and second insulating layers, the frame comprising a plurality of projections, each projection protruding from the frame and extending parallel to the surface of the insulating layer between a pair of adjacent suture holes. Optionally, the frame is separated from the conductive material by at least one additional insulating layer.

[0014] According to another embodiment of the first aspect, the projection of the frame is anchor-shaped, and preferably each of a pair of suture holes is located between the frame and the claw portion of the anchor-shaped projection.

[0015] According to a further embodiment of the first aspect, the frame comprises a polymer and / or metal.

[0016] According to another embodiment of the first aspect, the frame comprises polyetheretherketone (PEEK) or a nickel-titanium alloy.

[0017] According to yet another embodiment of the first aspect, the frame has a thickness of 0.15 to 1 mm, preferably 0.3 to 0.75 mm, and more preferably 0.45 to 0.55 mm.

[0018] According to another embodiment of the first aspect, the flat electrode comprises at least two pairs, at least three pairs, at least four pairs, at least five pairs, at least six pairs, at least seven pairs, or at least eight pairs of suture holes, more preferably six pairs, and up to 16 pairs, up to 14 pairs, up to 12 pairs, and up to 10 pairs of suture holes.

[0019] In one embodiment of the first aspect, the suture hole has a diameter of 0.5 to 3 mm, preferably 1 mm to 2 mm, and more preferably 1.3 to 1.7 mm.

[0020] According to a further embodiment of the first aspect, the first and second insulating layers include silicone, preferably reinforced silicone including an integrated polymer mesh, preferably PET mesh.

[0021] According to a further embodiment of the first aspect, the first insulating layer includes through holes passing through regions where the conductive material is located. Preferably, the number of through holes is between 10 and 500, more preferably between 30 and 400, even more preferably between 50 and 300, and most preferably between 55 and 260.

[0022] According to an embodiment of the first aspect, each through hole has a diameter of 0.5 to 5 mm, preferably 1 mm to 4.5 mm, more preferably 1.5 to 4 mm, even more preferably 2 to 3.5 mm, and most preferably 2.5 to 3.2 mm.

[0023] According to yet another embodiment of the first aspect, the electrical connector is in the form of a button. The button is preferably disposed on one of the distal surface portions of the conductive material. Preferably, the button further includes an inner button portion on the conductive material side, an outer button portion on the first insulating layer side, and a conductor fixedly sandwiched between the inner and outer button portions.

[0024] In a second aspect, the present invention further provides a manufacturing process for a flat electrode, comprising: a) creating a flexible conductive material, a frame, a first insulating layer including curable silicone rubber, at least a second insulating layer including curable silicone rubber and at least one opening, and a stitching hole penetrating the first and second insulating layers; b) disposing the conductive material on the first insulating layer and embedding its edge portion in the first insulating layer; c) laminating at least the second insulating layer on the assembly created in step b) such that the edge portion of the conductive material is covered by the second insulating layer and the central portion of the conductive material is exposed through at least one opening of the second insulating layer; and d) performing a post-curing treatment on the assembly obtained from step c).

[0025] According to an embodiment of the second aspect, the process further includes a step of disposing a frame between the first insulating layer and the second insulating layer before the lamination in step b). Preferably, the conductive material and the frame are separated from each other by at least one additional insulating layer before the lamination in step b).

[0026] In a third aspect, the present invention further provides an implantable lead assembly comprising an implantable coil electrode, an implantable flat electrode according to the first aspect of the present invention, and a control unit in which the coil electrode and the flat electrode are electrically connected via a conductor. The control unit is configured to establish a potential difference between the two electrodes so that a current can flow between the coil electrode and the flat electrode. The coil electrode is configured to be disposed in the right ventricle of the heart, and the flat electrode is configured to be disposed on the pericardium of the left ventricle outside the heart.

Brief Description of the Drawings

[0027] This disclosure will be more readily understood by referring to the following detailed description and considering it in conjunction with the accompanying drawings.

[0028] [Figure 1] It is a diagram of a flat electrode according to the present invention, schematically showing (A) the flat electrode from the conductive surface side, and (B) the electrically insulating surface side opposite to the conductive surface side. [Figure 2] It is a diagram of a flat electrode according to a preferred embodiment of the present invention, schematically showing the flat electrode (A) from the conductive surface side with a frame having protrusions after removing the second insulating layer, and (B) from the electrically insulating surface side opposite to the conductive surface side with perforations. [Figure 3] It is a diagram of a part of a flat electrode according to a preferred embodiment of the present invention with a frame, schematically showing (A) an i-shaped protrusion between a pair of suture holes, (B) an anchor-shaped protrusion between a pair of suture holes, and (C) a pair of suture holes fixed by a thread passing over the protrusion. [Figure 4]This is a cross-sectional view of a flat electrode according to the present invention, schematically illustrating the structure of a button-shaped electrical connector. [Figure 5] This figure schematically shows exemplary arrangements of the internal coil electrode and the external flat electrode according to a preferred embodiment of the present invention on the inside and outside of the heart as an internal organ. [Modes for carrying out the invention]

[0029] Detailed description of preferred embodiments The present invention will be described in more detail below with reference to the accompanying drawings. In the drawings, similar elements are indicated by the same reference numerals.

[0030] To facilitate understanding of this specification, certain terms are defined first. Further definitions are provided throughout the detailed explanation.

[0031] It should be noted that the articles “a” or “an” referring to an entity indicate that there is one or more entities; for example, “an opening” is understood to mean one or more “openings.” Therefore, the terms “a” (or “an”), “one or more,” and “at least one” can be used interchangeably in this specification.

[0032] Furthermore, when used herein, “and / or” should be interpreted as a specific disclosure of each of two designated features or components, the other of which may or may not be present. Accordingly, when the term “and / or” is used herein in expressions such as “A and / or B,” it is intended to include “A and B,” “A or B,” “A” (alone), and “B” (alone). Similarly, when the term “and / or” is used in expressions such as “A, B, and / or C,” it is intended to include each of the following embodiments, namely A, B, and C; A, B, or C; A or C; A or B; B or C; A and C; A and B; B and C; A (alone); B (alone); and C (alone).

[0033] Whenever an aspect is described in this specification using the phrase "including...", it is understood that other similar aspects are also presented, described using the terms "consisting solely of..." and / or "essentially consisting solely of...".

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the relevant field of the disclosure. For example, Korpas, David. Implantable cardiac devices technology. Berlin: Springer, 2013; Troutman, Leslie. "Dictionary of Medical Technology." RQ 32.3(1993):421-423 provides a general dictionary of many of the terms used herein.

[0035] Units, prefixes, and symbols are shown in the form recognized by the International System of Units (SI). Numerical ranges include the digits defining those ranges. The headings presented herein do not limit the various aspects of this disclosure that can be obtained by referring to this specification as a whole. Thus, the terms defined below are more fully defined by referring to this specification as a whole.

[0036] The term "approximately" is used herein to mean roughly, roughly, in the vicinity, or within a range. When used in conjunction with a numerical range, the term "approximately" relaxes that range by extending its boundaries above and below the stated number. Generally, the term "approximately" can relax a number above and below (greater or smaller than) the stated value by, for example, a variation of 10% above or below.

[0037] The terms “flat electrode,” “flat lead,” “patch electrode,” “patch lead,” or “patch” are used interchangeably herein and refer to flat, implantable medical devices. It should be understood that the design of a flat electrode must ensure its primary function, namely the distribution of electric current through biological tissue. Therefore, implantable flat electrodes generally have at least a conductive surface, an electrically insulating surface on the opposite side, and an electrical connector for coupling to a control / power supply unit. Such a flat electrode typically comprises a flexible, biocompatible, and biostable material for conforming to the geometric shape of the target tissue surface in such a way that contact between the tissue surface and most of the conductive surface of the flat electrode is possible, and fastening means for fixing and attaching it to the target tissue.

[0038] The terms “installed,” “attached,” “fixed,” “fastened,” or “securely fixed” are used to describe the positioning or attachment of electrodes to biological tissue. In the context of this disclosure, electrodes are attached, preferably by suture, to biological tissue such as the pericardium, below and / or on the surface of tissue surrounding an organ, for example, outside the left and / or right ventricle of the heart, or below and / or on the surface of tissue surrounding an organ. Flat electrodes may be positioned subcutaneously or outside the skin of the subject.

[0039] In the context of the present invention, the term “implantable flat electrode” refers to a flat electrode that can be implanted inside or outside the body. The term “biological tissue” refers to an external or internal organ. In the context of this disclosure, the biological tissue is preferably an internal organ selected from the group including the brain, nerve tissue, heart, kidney, liver, stomach, intestine, gallbladder, and pancreas, more preferably selected from the group including the heart, kidney, and liver, and most preferably the heart.

[0040] The term "suturing" refers to the fixation of an electrode to the target tissue by surgical sutures, which substantially include surgical thread passing through a first suture of a pair of adjacent suture holes, a portion of the tissue surface, and a second suture of a pair of adjacent suture holes, as shown in Figure 3C, and the portion of the electrode, including the pair of adjacent suture holes, is attached to the tissue by tying the ends of the thread together so that the thread forms a closed loop.

[0041] The terms “biocompatibility” or “biocompatible” refer to the appropriate biological requirements of one or more biomaterials used in a medical device, as well as the ability of the material to function with an appropriate host response in a particular application. In the context of this disclosure, “biocompatibility” specifically means that the material of the flat electrode 1 can function in the body without inducing harmful local or systemic responses. The terms “biostable” or “biostable” refer to the ability of the material to maintain its physical and chemical integrity after implantation in living tissue.

[0042] The term "electric current" refers to the flow of electricity, which may be direct current or alternating current. In the intended medical procedure, the current density at the flat electrode is preferably 0.1 to 100 μA / cm². 2 More preferably 0.5 to 10 μA / cm² 2 It will be adjusted to that.

[0043] Accordingly, the present invention provides a flat electrode for treating biological tissue with electric current, the flat electrode 1 comprising: first and second insulating layers 2, 3 laminated together, comprising elastic, biocompatible and biostable materials, wherein the second insulating layer 3 has at least one opening 3c; a flexible conductive material 4 sandwiched between the first and second insulating layers 2, 3, comprising an edge portion 4a embedded in the first insulating layer 2 and covered by the second insulating layer 3, and a central portion 4b exposed through at least one opening 3c of the second insulating layer 3 and not fixed to the first insulating layer 2; two or more pairs of suture holes 2a, 3a provided in the peripheral edge portions 2b, 3b of the first and second insulating layers 2, 3, wherein the edge portions 2b, 3b are laminated together without the conductive material 4 in between; and an electrical connector 6 electrically coupled to the conductive material 4.

[0044] The present invention offers the following design-related advantages: The first insulating layer 2 and the exposed portion 4b of the conductive material 4, due to their two-layer structure, provide high flexibility to the electrode 1 in the area of ​​the exposed portion 4b of the conductive material 4, allowing it to conform appropriately to the surface of the organ being treated. The peripheral edge portions 2b, 3b, including at least two layers, increase rigidity by dimensionally stabilizing the shape of the implanted electrode 1 compared to a typical single-layer structure. Furthermore, the at least two-layer structure around the suture holes 2a, 3a in the peripheral edge portions 2b, 3b reinforces the suture holes 2a, 3a against tearing of the sutures. By sandwiching the edge portion 4a of the conductive material 4 between the first and second insulating layers 2, 3 around the entire circumference, the fixation of the conductive material 4 and its edge portion 4a on the flat electrode 1 is further strengthened without the need for additional elements, and the risk of the conductive material 4 detaching from the flat electrode 1 after a certain period of time after implantation is reduced. Due to this effect, the size of the conductive material 4 is smaller in plan view than the size of the first insulating layer 2 and the second insulating layer 3. By embedding the edge portion 4a of the conductive material 4 into the first insulating layer 2, the central portion of the conductive material 4 is not fixed and can move relative to the first insulating layer 2, further increasing the flexibility of the electrode 1 in the region of the conductive material 4. This flexibility facilitates electrode implantation and allows for better conformity to the external shape of the target organ, such as the heart.

[0045] Those skilled in the art will understand that further preferred embodiments and specific designs of the flat electrode 1 of the present invention can be easily determined, within the context of the present invention, based on common general knowledge and the information provided herein, depending on their intended purpose and application site.

[0046] In an exemplary embodiment of the flat electrode 1, at least one opening 3c of the second insulating layer 3 is a central opening.

[0047] In a preferred embodiment of the flat electrode 1 according to the present invention, the conductive material 4 is embedded in or bonded to a first insulating layer 2 and / or a second insulating layer 3, preferably the edge portion 4a of the conductive material 4 is embedded in the first insulating layer 2 and covered by the second insulating layer 3.

[0048] In one preferred embodiment of the flat electrode 1 according to the present invention, the conductive material 4 comprises a metal mesh. Preferably, the metal mesh comprises platinum, more preferably a platinum-iridium alloy. The platinum-iridium alloy preferably has a platinum-iridium alloy ratio of 70:30 to 99:1, more preferably 80:20 to 95:15, and most preferably 88:12 to 92:8. Platinum and its alloys possess inherent corrosion resistance, high biocompatibility, and radiopaqueness, making them ideal candidates for a variety of medical applications. In an exemplary embodiment, the conductive material 4 comprises woven platinum-iridium 90:10 wire, with a single wire outer diameter of 43 μm, a mesh pattern of 1:1, and a mesh width of 150 wires / inch.

[0049] In a further preferred embodiment of the flat electrode 1 according to the present invention, the conductive material 4 has a constricted shape in plan view, including two distal portions connected by a central constriction in its longitudinal direction, and the width w of the central constriction 4c m The width of the distal portion 4d relative to w d1 , w d2 The ratio is 2:1 to 6:1, preferably 3:1 to 5:1. As shown by the arrow in Figure 1A, the width w of the distal portion 4d. d1 , w d2 and the width of the constricted part 4c w mis measured perpendicular to the longitudinal axis of the flat electrode 1. In a preferred embodiment, the specific measurement points shown in FIG. 1A should be used. However, this should not be understood as a limitation, and such measurements may be made at any suitable point of each part. Therefore, any constriction shape in which all of the ratios between each of the widths of the constriction part 4c and each of the widths of the distal part 4d are within the range of 1.5:1 to 7:1, preferably 2:1 to 6:1, more preferably 3:1 to 5:1 can be realized. Further, the width w d1 is equal to the width w d2 , greater than the width w d2 , or less than the width w d2 may be.

[0050] According to the constriction shape according to an embodiment of the present invention, the flat electrode 1 can be bent about two axes perpendicular to each other on the curved surface while preventing interference between its individual parts and keeping the mechanical stress on the individual parts of the electrode low. Further, this shape also enables the electrode to conform to the uneven surface of the biological tissue.

[0051] As shown in FIGS. 1 and 2, in a specific embodiment, the central constriction part 4c merges with the distal part 4d via rounded corners. On both sides between the rounded corners of the opposing distal parts 4d, the central constriction part 4c includes straight outer edges. This specific design of the central constriction part 4c prevents the notch effect in the region of the constriction part 4c that may occur due to stress concentration when the flat electrode is deformed, reduces wear in the region of the central constriction part 4c, and thus improves the durability of the conductive material 4. Regarding this effect, any shape in which all of the ratios between the length of the straight edge and the radius of the rounded corner are within the range of 1:3 to 6:1, preferably 1:1 to 4:1, more preferably 4:3 to 2:1 is possible. The ratio between the length of the straight edge and the radius of the rounded corner may be 3:2.

[0052] In one preferred embodiment of the flat electrode 1 according to the present invention, the flat electrode further comprises a frame 5 disposed between first and second insulating layers 2, 3, the frame 5 comprising a plurality of projections 5a, each projection 5a protruding from the frame 5 and extending parallel to the surface of the insulating layer between a pair of adjacent suture holes 2a, 3a. In a further preferred embodiment, the conductive material 4 and the frame 5 are separated from each other by at least one additional insulating layer.

[0053] The inventors of the present invention have surprisingly found that by providing projections 5a on the frame 5, with each projection 5a protruding from the frame 5 and extending parallel to the surface of the insulating layer between a pair of adjacent suture holes 2a, 3a, the flat electrode 1 is reinforced by the frame 5 while still allowing sufficient flexibility so that the electrode 1 can be positioned snugly against the typically uneven surface of the biological tissue to which it is sutured. The tensile load applied by the sutures to the pair of adjacent suture holes 2a, 3a is largely distributed and absorbed by the robust projections 5a, thereby significantly improving the durability of the pair of adjacent suture holes 2a, 3a against delamination, deformation, and tearing while maintaining an appropriate degree of flexibility in the portion of the electrode 1 including the pair of adjacent suture holes 2a, 3a. At least one additional insulating layer provides additional insulation between the frame 5 and the conductive material 4, which is particularly beneficial when the frame 5 contains a conductive material such as metal.

[0054] In another preferred embodiment of the flat electrode 1 according to the present invention, the projection 5a is anchor-shaped, and preferably, each of a pair of suture holes 2a, 3a is located between the frame 5 and the claw portion 5b of the anchor-shaped projection.

[0055] The claw portion 5b of the anchor-shaped projection 5a further reinforces the suture holes 2a and 3a in the direction away from the frame 5. Optionally, the projection 5a can have different shapes; for example, it may be i-shaped, hook-shaped, thorn-shaped, club-shaped, or conical, and the shapes of the projections 5a of the flat electrodes 1 may differ from each other.

[0056] In a further preferred embodiment of the planar electrode 1 according to the present invention, the insulating layers, i.e., the first insulating layer 2, the second insulating layer 3, and / or any additional insulating layers, include silicone, preferably a reinforced silicone containing a polymer mesh integrated as monofilament or multifilament, the polymer mesh preferably containing polyester, PET, and / or PETG.

[0057] The integrated polymer mesh further enhances the stability of the silicone material, particularly against tearing. Furthermore, by specifically selecting a particular integrated polymer mesh, the stiffness and strength of the silicone material can be adjusted without changing the thickness of the flat electrode 1. This makes it possible to tailor the mechanical properties of the flat electrode 1 material to individual requirements.

[0058] In a further preferred embodiment of the flat electrode 1 according to the present invention, the flat electrode 1 includes at least two pairs, at least three pairs, at least four pairs, at least five pairs, at least six pairs, at least seven pairs, or at least eight pairs of suture holes, more preferably six pairs, and up to 16 pairs, up to 14 pairs, up to 12 pairs, and up to 10 pairs of suture holes.

[0059] In a further preferred embodiment of the flat electrode 1 according to the present invention, the suture hole has a diameter of 0.5 to 3 mm, preferably 1 mm to 2 mm, and more preferably 1.3 to 1.7 mm.

[0060] In a further preferred embodiment of the flat electrode 1 according to the present invention, the first insulating layer 2 includes perforations 2c passing through the region where the conductive material 4 is located, preferably the number of perforations 2c is between 10 and 500, more preferably between 30 and 400, even more preferably between 50 and 300, and most preferably between 55 and 260. Each of the perforations 2c preferably has a diameter of 0.5 to 5 mm, more preferably 1 mm to 4.5 mm, more preferably 1.5 to 4 mm, even more preferably 2 to 3.5 mm, and most preferably 2.5 to 3.2 mm.

[0061] For example, in rare cases of flat electrodes implanted outside the heart and having a first insulating layer 2 without perforations, the inventors of the present invention have observed that, some time after implantation, fibrous tissue grows through the conductive material 4, resulting in excessive formation of fibrous tissue (fibrosis) between the conductive material 4 and the first insulating layer 2, which causes undesirable deformation and, in the worst case, leads to separation of the flat electrode from the target tissue. If perforations 2c are provided in the first insulating layer 2, the fibrous tissue growing through the conductive material 4 can continue to grow outside the flat electrode through the perforations 2c in the first insulating layer 2, thereby preventing the accumulation of excessive fibrosis between the conductive material 4 and the first insulating layer 2. In this way, the perforations 2c reduce the risk of deformation and separation of the flat electrode 1. For long-term use in implantable devices, the frame material needs to have mechanical strength, appropriate rigidity, biocompatibility, as well as high-temperature chemical resistance, moldability, and stability for the manufacture of the electrode 1. Through experiments, the inventors of the present invention have found that metals, specifically metal alloys such as nickel-titanium alloys, and polymers such as polyimide, high-density polyethylene (HDPE), polytetrafluoroethylene (PTFE), and specifically polyetheretherketone (PEEK) exhibit these properties and are therefore suitable as frame materials.

[0062] Therefore, in a preferred embodiment of the flat electrode 1 according to the present invention, the frame 5 comprises a polymer such as polyimide, HDPE, PTFE, and PEEK, preferably PEEK.

[0063] Therefore, in a preferred embodiment of the flat electrode 1 according to the present invention, the frame 5 comprises a metal, preferably a platinum alloy and / or a titanium alloy, most preferably a nickel-titanium alloy.

[0064] In a further preferred embodiment of the flat electrode 1 according to the present invention, the frame 5 has a thickness of 0.15 to 1 mm, preferably 0.3 to 0.75 mm, and more preferably 0.45 to 0.55 mm.

[0065] In a further preferred embodiment of the flat electrode 1 according to the present invention, the electrical connector 6 is in the form of a button. The button is preferably located on one of the distal surface portions 4d of the conductive material 4. Preferably, the button 6 further comprises an inner button portion 6a on the conductive material side, an outer button portion 6b on the first insulating layer side, and a conductor 7 configured to connect to a control unit and fixed and sandwiched between the inner and outer button portions 6a, 6b. The fixing of the conductor 7 between the inner and outer button portions 6a, 6b is preferably done by welding, more preferably by laser welding. The outer button portion 6b may be further insulated by a cover, preferably a silicone cover.

[0066] Furthermore, the present invention provides a process for manufacturing a flat electrode, comprising: a) preparing a flexible conductive material 4, a frame 5, a first insulating layer 2 including curable silicone rubber, at least a second insulating layer 3 including curable silicone rubber and at least one opening 3c, and a suture hole penetrating the first and second insulating layers 2 and 3; b) placing the conductive material 4 on the first insulating layer 2 and embedding its edge portion 4a into the first insulating layer 2; c) laminating at least the second insulating layer 3 onto the assembly created in step b) such that the edge portion 4a of the conductive material 4 is covered by the second insulating layer 3 and the central portion 4b of the conductive material 4 is exposed through at least one opening 3c of the second insulating layer 3; and d) subjecting the assembly obtained from step c) to a post-curing treatment.

[0067] The use of a curable silicone layer that is not fully crosslinked allows for adhesive-free bonding in sandwich structures that include silicone polymer reinforcement.

[0068] In a preferred embodiment of the manufacturing process for a flat electrode, the process further includes the step of placing a frame 5 between the first insulating layer 2 and the second insulating layer 3 before lamination in step b). The conductive material 4 and the frame 5 are more preferably separated from each other by at least one additional insulating layer before lamination in step b). The at least one additional insulating layer provides additional insulation between the frame 5 and the conductive material 4, which is particularly beneficial when the frame 5 contains a conductive metal.

[0069] In an exemplary embodiment of the manufacturing process, first and second insulating layers 2, 3, both containing curable silicone rubber, were cut using a 2D cutting table and / or punch. The contours of the first and second insulating layers 2, 3, suture holes 2a, 3a, central opening 3c, and perforation 2c were cut layer by layer by control of a cutting programmable file on a 2D cutting table and / or using a specific punching tool. As the conductive material 4, a 150-mesh platinum-iridium alloy (Pt-Ir) mesh, woven 1:1 with a platinum-iridium alloy ratio of 90:10 and a wire thickness of 40 μm, was contour-cut by laser cutting. The frame 5 was cut from PEEK by waterjet cutting and has a thickness of 0.5 mm.

[0070] The Pt-Ir mesh is circumferentially welded to the first insulating layer 2 by pressing the cut wire ends into the uncured silicone material of the first insulating layer 2 at approximately 5 bar and approximately 120°C using a contour sealing plate, thereby fixing the wire ends to the first insulating layer 2.

[0071] Next, the PEEK frame 5 is positioned around the circumferential weld of the fixed wire end, and the second insulating layer 3 is positioned on top of the first insulating layer 2, the PEEK frame 5, and the circumferential weld of the Pt-Ir mesh, with the central portion 4b of the Pt-Ir mesh exposed through the central opening 3c of the second insulating layer 3, and the circumferential weld is sealed with a pressure plate of about 5 bar and about 120°C so that the second insulating layer 3 covers the circumferential weld, thereby obtaining a layered electrode assembly.

[0072] In the final step, the assembly is placed in a curing oven and heated to post-cur the electrode assembly, allowing the silicone material to vulcanize throughout.

[0073] Alternatively, instead of welding or vulcanization, molding may be performed by an adhesive process or silicone injection molding.

[0074] Furthermore, the present invention provides an implantable lead assembly comprising an implantable coil electrode 8, an implantable flat electrode 1 according to an embodiment of the present invention, and a control unit to which the coil electrode 8 and the flat electrode 1 are electrically connected via connector wirings 7 and 9, wherein the control unit is configured to establish a potential difference between the two electrodes 1 and 8 so that current can flow between the coil electrode 8 and the flat electrode 1, the coil electrode 8 is configured to be positioned inside the right ventricle of the heart, and the flat electrode 1 is configured to be positioned on the pericardium of the left ventricle outside the heart.

[0075] According to a preferred embodiment of the present invention, the implantable electrode assembly is configured to apply a microcurrent between a flat electrode 1 and a coil electrode 8 to the heart, preferably to treat heart failure. To improve cardiac function in patients with heart failure by directly applying a microcurrent along with an electric field to the heart, a preferred current density is 1.5 to 10 μA / cm². 2 All embodiments of the present invention described herein can be combined in any combination, unless a person skilled in the art would consider such a combination to be without technical significance. [Explanation of symbols]

[0076] 1 flat electrode 2. First insulating layer 3. Second insulating layer 2a,3a suture hole 2b, 3b Peripheral edge portion 2c perforation 3c central opening 4. Conductive materials 4a Edge portion 4b central part 4c Waist area 4d distal part 5 frames 5a Protrusion 5b Claw part 6. Electrical connectors 6a Inside button area 6b Outer button area 7,9 Conductor 8 Coil electrodes

Claims

1. A flat electrode for treating biological tissue with electric current, Laminated first and second insulating layers (2, 3) comprising an elastic, biocompatible, and biostable material, wherein the second insulating layer (3) has at least one opening (3c), A flexible conductive material (4) sandwiched between the first and second insulating layers (2, 3), The edge portion (4a) embedded in the first insulating layer (2) and covered by the second insulating layer (3), and The central portion (4b) of the second insulating layer (3) that is exposed through the at least one opening (3c) and is not fixed to the first insulating layer (2) A conductive material (4) containing, Two or more pairs of suture holes (2a, 3a) are provided in the peripheral edge portions (2b, 3b) of the first and second insulating layers (2, 3), wherein the edge portions (2b, 3b) are laminated together without the conductive material (4) in between, and the two or more pairs of suture holes (2a, 3a) An electrical connector (6) electrically coupled to the conductive material (4) and A flat electrode comprising:

2. The flat electrode according to claim 1, wherein the conductive material (4) includes a metal mesh, preferably the metal mesh includes platinum, more preferably a platinum-iridium alloy, and the platinum-iridium alloy preferably has a platinum-iridium alloy ratio of 70:30 to 99:1, more preferably 80:20 to 95:15, and most preferably 88:12 to 92:

8.

3. The conductive material (4) has a constricted shape in plan view, comprising two distal portions (4d) connected by a constricted portion (4c) in its longitudinal direction, and the ratio of the width of the distal portion (4d) perpendicular to the longitudinal direction to the constricted portion (4c) is 1.5:1 to 7:1, preferably 2:1 to 6:1, more preferably 3:1 to 5:1, the flat electrode according to claim 1 or 2.

4. The flat electrode according to any one of claims 1 to 3, further comprising a frame (5) disposed between the first and second insulating layers (2, 3), wherein the frame (5) comprises a plurality of projections (5a), each projection (5a) protruding from the frame (5) and extending parallel to the surface of the insulating layer between a pair of adjacent suture holes (2a, 3a), and optionally the frame (5) being separated from the conductive material (4) by at least one further insulating layer.

5. The flat electrode according to claim 4, wherein the projection (5a) is anchor-shaped, and preferably each of the pair of suture holes (2a, 3a) is located between the frame (5) and the claw portion (5b) of the anchor-shaped projection.

6. The flat electrode according to claim 4 or 5, wherein the frame (5) comprises a polymer and / or a metal.

7. The flat electrode according to claim 6, wherein the frame (5) comprises polyetheretherketone (PEEK) or a nickel-titanium alloy.

8. The frame (5) has a thickness of 0.15 to 1 mm, preferably 0.3 to 0.75 mm, more preferably 0.45 to 0.55 mm, as described in any one of claims 4 to 7.

9. A flat electrode according to any one of claims 1 to 8, comprising at least two pairs of suture holes (2a, 3a), at least three pairs, at least four pairs, at least five pairs, at least six pairs, at least seven pairs, or at least eight pairs, more preferably six pairs of suture holes (2a, 3a), and further comprising up to 16 pairs, up to 14 pairs, up to 12 pairs, and up to 10 pairs of suture holes (2a, 3a).

10. The flat electrode according to any one of claims 1 to 9, wherein the suture holes (2a, 3a) have a diameter of 0.5 to 3 mm, preferably 1 mm to 2 mm, and more preferably 1.3 to 1.7 mm.

11. The flat electrode according to any one of claims 1 to 10, wherein the insulating layer comprises silicone, preferably reinforced silicone including an integrated polymer mesh, preferably PET mesh.

12. The flat electrode according to any one of claims 1 to 11, wherein the first insulating layer (2) includes perforations (2c) passing through the region where the conductive material (4) is located, and preferably the number of perforations (2) is between 10 and 500, more preferably between 30 and 400, even more preferably between 50 and 300, and most preferably between 55 and 260.

13. The flat electrode according to claim 12, wherein each of the perforations (2) has a diameter of 0.5 to 5 mm, preferably 1 mm to 4.5 mm, more preferably 1.5 to 4 mm, even more preferably 2 to 3.5 mm, and most preferably 2.5 to 3.2 mm.

14. The electrical connector (6) is in the form of a button, preferably, The button is positioned on one side of the distal portion (4d) of the conductive material (4). Preferably, the button (6) is further, The inner button portion (6a) on the conductive material side, the outer button portion (6b) on the first insulating layer side, and the conductor (7) fixed and sandwiched between the inner and outer button portions (6a, 6b) A flat electrode according to any one of claims 1 to 13, comprising:

15. A process for manufacturing a flat electrode according to any one of claims 1 to 14, a) A step of preparing a flexible conductive material (4), a frame (5), a first insulating layer (2) comprising curable silicone rubber, at least a second insulating layer (3) comprising curable silicone rubber and at least one opening (3c), and suture holes (2a, 3a) penetrating the first and second insulating layers (2, 3), b) A step of placing the conductive material (4) on the first insulating layer (2) and embedding the edge portion (4a) of the conductive material (4) into the first insulating layer (2), c) Laminating at least the second insulating layer (3) onto the assembly created in step b) such that the edge portion (4a) of the conductive material (4) is covered by the second insulating layer (3) and the central portion (4b) of the conductive material is exposed through the at least one opening (3c) of the second insulating layer (3), d) A step of applying a post-hardening treatment to the assembly obtained from step c) A manufacturing process for flat electrodes, including the process itself.

16. A process for manufacturing a flat electrode according to claim 15, further comprising the step of placing a frame (5) between the first insulating layer (2) and the second insulating layer (3) before lamination in step b), wherein optionally the conductive material (4) and the frame (5) are separated from each other by at least one additional insulating layer before lamination in step b).

17. The device comprises an implantable coil electrode (8), an implantable flat electrode (1) according to any one of claims 1 to 14, and a control unit in which the coil electrode (8) and the flat electrode (1) are electrically connected via conductors (7, 9), The control unit is configured to establish a potential difference between the two electrodes (1, 8) so that current can flow between the coil electrode (8) and the flat electrode (1). The coil electrode (8) is configured to be positioned in the right ventricle of the heart. The flat electrode (1) is configured to be placed on the pericardium of the left ventricle on the outside of the heart. Implantable lead assembly.

Images