Circular electrode array, and method of forming the circular electrode array

Abstract

An electrode array for a catheter includes a plurality of electrodes spaced apart from one another on a shared member of the electrode array. The electrode array also includes a plurality of conductive electrode wires coupled to the electrodes, and a first layer of hardened polymer material formed from a first, linear mold and extending through each of the electrodes. Each of the electrode wires is encapsulated within the first layer of hardened polymer material. The electrode array also includes a second layer of over- molded, hardened polymer material formed from a second, non-linear mold and extending over and encapsulating a portion of the first layer of hardened polymer material. The second layer of over-molded, hardened polymer material engages each of the electrodes.

Description

CIRCULAR ELECTRODE ARRAY, AND METHOD OF FORMING THE CIRCULAR ELECTRODE ARRAY

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 580,817, filed September 6, 2023, the entire content of which is incorporated herein by reference.FIELD

[0002] The present technology is generally related to an electrode array for use during a medical procedure, and to a method of forming the electrode array.BACKGROUND

[0003] Electrode arrays often are used during a medical procedure. The electrode arrays commonly include a plurality of electrodes arranged in a loop.

[0004] For example, during some treatments of atrial fibrillation, the distal end of a delivery catheter is first moved and steered into the left atrium of the heart. A separate diagnostic catheter (e.g., an electrophysiology catheter) is then inserted through the delivery catheter. The diagnostic catheter includes an electrode array having a plurality of electrodes that detect and measure electrical signals from the pulmonary veins. Those signals are then sent back through the diagnostic catheter, and the signals are recorded and mapped. The electrodes are used to map the electrical conduction between the left atrium and pulmonary veins. Once the mapping is complete, an ablation catheter (e.g., a cryogenic balloon catheter) is then inserted through the delivery catheter. The ablation catheter is used to deliver ablation energy (e.g., cold energy via a refrigerant), creating scar tissue at the opening of the pulmonary vein. This scar tissue is intended to stop the transmission of electrical signals that cause atrial fibrillation. Once the ablation is complete, the diagnostic catheter and its electrode array are then used again to obtain measurements of the electrical signals, to determine whether the ablation was successful.

[0005] In other examples, electrode arrays are used as part of a delivery catheter itself that delivers energy (e.g. pulsed field ablation (PFA) or radio frequency energy) to treat atrial fibrillation.SUMMARY

[0006] The techniques of this disclosure generally relate to the formation of electrode arrays for use during medical procedures such as atrial fibrillation. The electrode arrays are formed through a two-step molding process.

[0007] In one aspect, the disclosure provides an electrode array for a catheter. The electrode array includes a plurality of electrodes spaced apart from one another on a shared member of the electrode array. The electrode array also includes a plurality of conductive electrode wires coupled to the electrodes, and a first layer of hardened polymer material formed from a first, linear mold and extending through each of the electrodes. Each of the electrode wires is encapsulated within the first layer of hardened polymer material. The electrode array also includes a second layer of over-molded, hardened polymer material formed from a second, non-linear mold and extending over and encapsulating a portion of the first layer of hardened polymer material. The second layer of over- molded, hardened polymer material engages each of the electrodes.

[0008] In another aspect, the disclosure provides a mold assembly for forming an electrode array for a catheter. The mold assembly includes a first, linear mold for molding a first portion of the electrode array, and a second, non-linear mold for molding a second portion of the electrode array. The first, linear mold includes a first, elongate cavity extending along an axis and sized and shaped to be filled with a first molten polymer material to encapsulate a set of electrode wires in the first molten polymer material. The first, linear mold is further shaped such that the first molten polymer material is configured to pass through a plurality of electrodes of the electrode array. The second, non-linear mold includes a second, non-linear cavity sized and shaped to be filled with a second molten polymer material to encapsulate at least a portion of the first polymer material after the first polymer material has hardened, and to engage the plurality of electrodes.

[0009] In another aspect, the disclosure provides a method of forming an electrode array. The method includes using a first, linear mold to form a first layer of polymer material, wherein the first layer encapsulates a set of electrode wires and extends through a plurality of electrodes. The method further includes using a second, non-linear mold toform a second, over-molded layer of polymer material, wherein the second layer extends over and encapsulates a portion of the first layer.

[0010] The details of one or more aspects of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the techniques described in this disclosure will be apparent from the description and drawings, and from the claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1 is a perspective view of an electrode array according to one example.

[0012] FIG. 2 is a top plan view of a first, linear mold for forming the electrode array of FIG. 1.

[0013] FIG. 3 is a perspective view of the first, linear mold, illustrating electrodes positioned in the first, linear mold.

[0014] FIG. 4 is a top plan view of a second, non-linear mold for forming the electrode array of FIG. 1.

[0015] FIG. 5 is a perspective view of the second, non-linear mold, with a portion of the electrode array of FIG. 1 arranged within the second, non-linear mold.

[0016] FIG. 6 is a schematic illustration of the first, linear mold and a cross-section of the electrode array of FIG. 1 after a first molding step.

[0017] FIG. 7 is a schematic illustration of the second, non-linear mold and a cross-section of a portion of the electrode array of FIG. 1 after a second molding step.

[0018] FIG. 8 is a schematic, cross-sectional image of the electrode array of FIG. 1, taken between two electrodes along the electrode array, after both the first and second molding steps.

[0019] FIG. 9 is a cross-sectional image of another electrode array, taken between two electrodes, and formed without the first and second molding steps for comparison.

[0020] FIG. 10 is a schematic, cross-sectional image of the electrode array of FIG. 1, taken at one of the electrodes, after both the first and second molding steps,.

[0021] FIG. 11 is a cross-sectional image of another electrode array, taken at one of the electrodes, and formed without the first and second molding steps for comparison.

[0022] FIG. 12 is a schematic side view of the electrode array of FIG. 1, after both the first and second molding steps.

[0023] FIG. 13 is a side view of the electrode array of FIG. 1, after both the first and second molding steps.

[0024] FIG. 14 is a side view of another electrode array, illustrating adhesive fillets for comparison.

[0025] FIG. 15 is a side view of another electrode array, illustrating an electrode with rounded, swaged edges for comparison.

[0026] FIG. 16 is a perspective view of a step of an atrial fibrillation procedure that may incorporate use of the electrode array of FIG. 1.

[0027] FIGS. 17-19 are perspective views of steps of an atrial fibrillation procedure that may incorporate the use of the electrode array of FIG. 1.DETAILED DESCRIPTION

[0028] Overmolding of electrode arrays in general is a good way to minimize strain and insulate respective components, though the more components that are involved the more complex the molding process becomes. In examples where there are not only numerous components, but also that many of these components need to be insulated from each other (such as when they are separate electrode wires), this complexity can grow exponentially. Beyond this, where the voltages being delivered by electrode wires are particularly high (e.g., at least 1.5 kV for PFA applications), manufacturing of these arrays will require applying double this voltage load (e.g., applying around 3kV during manufacture), which itself further increases the risk of shorting. In some instances, an electrode array with a multitude of electrodes (e.g., more than 5 or 6 electrodes) would bewelded together with laser welds and adhesive, but given the close proximity of the components any wire damage that occurred at the weld (or nearby other wires) would potentially cause shorting between the welds. Insulation sleeves may also be tacked in place using adhesive for conventional assemblies, where movement during use can shift the nitonol wire insulation sleeve making it more likely for shorting and / or for damaged regions to meet. Further, in some conventional embodiments swaged electrodes may be used, but (particularly when the electrode arrays include a significant number of electrode wires and electrodes) it may be difficult to maintain a seal between the electrodes, the polymer tube, and holes where electrode wires exit, enabling blood ingress. In some conventional instances, adhesive filets may be used to fix electrodes in place (e.g., to produce a desired electrical field for PFA), but the adhesive is often highly susceptible to sterilization, and creates risk of particulate being dispersed during a procedure. Beyond this, in certain conventional embodiments a single overmolding will result in an assembly where heating processes (e.g., ablation procedures where heat is either intended or a byproduct of another treatment) may cause walls to melt, therein exposing electrode wires within and potentially resulting in an increased chance of electrical shorting.

[0029] FIG. 1 illustrates an electrode array 10 formed by a two-step molding process. The electrode array 10 may be used in medical procedures, such as atrial fibrillation or other procedures, and may for example address one or more of the problems described above. In the illustrated example, the electrode array 10 includes a main body 14, and a plurality of electrodes 18a - 18i (collectively or individually referred to herein as "electrodes 18" or "electrode 18," respectively) that are positioned along an exterior of the main body 14. The illustrated example includes nine electrodes 18, although other examples include different numbers of electrodes 18 (e.g., six electrodes, seven electrodes, eight electrodes, ten electrodes, eleven electrodes, twelve electrodes, etc.). Additionally, in the illustrated example, the electrodes 18 are spaced evenly apart from one another along the main body 14 at predetermined distances (e.g., based on the type of medical procedure to be implemented), although in other examples the spacing of and / or distances between the electrodes 18 may be different than that illustrated.

[0030] With continued reference to FIG. 1, the main body 14 is flexible, and is formed for example from a polymer (e.g., a thermoplastic elastomer such as polyamide,polyether block amide, and / or Pebax®). As illustrated in FIG. 1, at least a portion of the main body 14 may be bent, twisted, or otherwise curved into a non-linear (e.g., circular) shape. The electrodes 18 may be less flexible than the main body 14, and are formed for example from a metallic material (e.g., gold, platinum, or other suitable materials). Each of the electrodes 18 is coupled to the main body 14, and is also coupled to a respective conductive electrode wire 22a-22i (collectively or individually referred to herein as "electrode wires 22" or "electrode wire 22," respectively)). The electrode wires 22 are elongate wires (e.g., flexible elongate wires) that pass through the main body 14 to deliver electrical energy or signals to and / or from the electrodes 18.

[0031] With continued reference to FIG. 1, in the illustrated example the electrode array 10 further includes a guidewire 26 that extends through the main body 14. The guidewire 26 is an elongate wire (e.g., flexible elongate wire) that helps the electrode array 10 to maintain a particular shape (e.g., circular shape), and / or guides movement of the electrode array 10. Other examples do not include the use of a guidewire 26. In the illustrated example, the guidewire 26 is formed at least partially from nitinol (a metal alloy of nickel and titanium), although other examples include other suitable materials.

[0032] With reference to FIGS. 2-8, the illustrated electrode array 10 is formed via a two-step molding process. FIGS. 2 and 3 illustrate a first, linear mold 30 for molding a first portion 34 (FIG. 6) of the main body 14 of the electrode array 10 during a first molding step. FIGS. 4 and 5 illustrate a second, non-linear mold 38 for molding a second portion 42 (FIG. 7) of the main body 14 of the electrode array 10 during a second molding step.

[0033] In the illustrated example, the first linear mold 30 includes a first, elongate cavity 46 extending along an axis 50. The first cavity 46 is sized and shaped to be filled with a first molten polymer material (e.g., plastic, Pebax@)etc.) to encapsulate (fully or partially) the electrode wires 22 in the first molten polymer material. The first, linear mold 30 is shaped such that the first molten polymer material passes through the electrodes 18 (e.g., through central openings formed by the electrodes 18) when the electrodes 18 are positioned in the mold (FIG. 3). The first molten polymer material may also engage surfaces (e.g., inner surfaces) of the electrodes 18, such that when the firstmolten polymer material cools and hardens, the electrodes 18 are firmly engaged by the first molten polymer material, and are locked in position and spacing relative to one another. In the illustrated example, the first, linear mold 38 may further include a mandrel 54 (FIG. 6) that extends linearly along the first, elongate cavity 46. The first molten polymer material flows around the mandrel 54, such that when the mandrel 54 is removed after the first polymer material has hardened, an elongate linear channel is formed through the first portion 34 of the main body 14 for insertion of the guidewire 26. In other examples, a lubricious sleeve may be wrapped around the mandrel 54. The sleeve may be left in place after molding to help remove the mandrel 54 and push the guidewire 26 through the channel.

[0034] With reference to FIGS. 4 and 5, the second, non-linear mold 38 includes a second, non-linear cavity 58 sized and shaped to be filled with a second molten polymer material (e.g., plastic, Pebax@), etc.) that encapsulates at least a portion of the first polymer material after the first polymer material has hardened, and engages the plurality of electrodes 18. In the illustrated example, the non-linear cavity 58 of the second, nonlinear mold 38 is circular, although other examples include different shapes (e.g., oval, etc.). Additionally, in the illustrated example the first polymer material and the second polymer material are an identical type of polymer material, although in other constructions the second polymer material is a different type of polymer material than the first polymer material.

[0035] With reference to FIGS. 2-8, during the first molding step the electrodes 18 are first placed into the first, linear mold 30, along the elongate cavity 46. The first molten polymer material is then injected into the elongate cavity 46, and cools to form a first hardened layer 62 (FIG. 6) of molded polymer material. This injection-molding process may push the polymer material at high pressure, driving out air in the first linear mold 30. As seen in FIG. 6, the cooled, first hardened layer 62 at least partially encapsulates each of the electrode wires 22, and also extends through the electrodes 18 (e.g., through the central openings formed by the ring-shaped electrodes 18). The first hardened layer 62 also engages and seals itself against inner surfaces 66 (e.g., radially inner surfaces) of the electrodes 18.

[0036] In some examples, the first hardened layer 62 includes regions of different diameter. For example, as illustrated in FIG. 6, in some examples the first hardened layer 62 includes a first diameter DI between two of the electrodes 18, and a second, larger diameter D2 where the first hardened layer 62 passes through the electrodes 18. In yet other examples the first hardened layer 62 includes three or more different diameters, and / or a diameter that tapers and gradually increases or decreases, rather than abruptly changing in a step-wise manner.

[0037] During the first molding step, and in the illustrated example, the mandrel 54 is inserted within the first, linear mold 30. The first molten polymer material flows around and encapsulates the mandrel 54, and hardens around the mandrel 54. Once the first molten polymer material has hardened into the first hardened layer 62, the mandrel 54 is then removed, leaving an open channel extending (e.g., longitudinally) through the hardened first hardened layer 62. The guidewire 26 is inserted through this channel. In some examples, the guidewire 26 has a diameter that is approximately half of the diameter DI or D2, and the electrode wires 22 have diameters that are less than half of the diameter DI or D2. The guidewire 26 may be larger in diameter than each of electrode wires 22. Other examples include other values, ranges of values, or ratios of diameters than that illustrated.

[0038] In some examples, the guidewire 26 is inserted through the open channel left by the mandrel 54, prior to moving on to the second molding step. As noted above, the guidewire 26 may help the electrode array 10 to maintain a particular shape (e.g., a circular shape). Accordingly, in some examples the guidewire 26 may be pre-formed, or pre-stressed, such that it naturally assumes a curved (e.g., circular) shape. When the guidewire 26 is inserted into the open channel left by the mandrel 54, the guidewire 26 may try to assume its natural shape, thereby bending and / or stressing the first hardened layer 62 to begin to assume a final (e.g., circular) shape.

[0039] With reference to FIGS. 7 and 8, during the second molding step, the electrode array 10 is first bent or curved (e.g., manually, with machine assistance, and / or via the guidewire 26 itself acting on the electrode array 10). The electrode array 10 is then placed inside the non-linear cavity 58 of the second, non-linear mold 38. The secondmolten polymer material is then directed into the non-linear cavity 58 (e.g., at high pressure, similar to the first molding step). The second molten polymer material flows around the outside of the first, hardened layer 62, and then cools to form a second, overmolded, hardened layer 70 of polymer material. This second hardened layer 70 of polymer material extends over and encapsulates at least a portion of the first hardened layer 62.

[0040] With continued reference to FIG. 7, the second hardened layer 70 engages and seals against edges (e.g., sidewalls) 74 of the electrodes 18. By molding in a nonlinear (e.g., circular) configuration in the second, non-linear mold 38, a distinct feature is that the second hardened layer 70 not only reaches the edges 74 of the electrodes 18, but also conforms to the edges 74 when the electrode array 10 is in its natural, non-linear (e.g., circular) shape. This sealing and / or conforming of the second hardened layer 70 may inhibit or prevent fluid ingress or edge effects when delivering energy during use (e.g., as described further below). In the illustrated example, each of the electrodes 18 is ringshaped, and includes straight-cut edges 74. The straight-cut edges 74 extend parallel to one another, and are arranged as sidewalls (e.g., flat sidewalls) of the electrode 18. One of the edges 74 is at one end (e.g., proximal end) of the electrode, and the other edge 74 is at another end (e.g., distal end) of the electrode 18. Each electrode 18 also includes a rounded, outer surface 78 that extends between the two edges 74. In the illustrated example, the second hardened layer 70 fully engages and covers the edges 74, such that a portion of the second hardened layer 70 reaches an outermost diameter D3 of each electrode 18 (i.e., the diameter at the rounded outer surface 78), and such that an outer diameter of the second layer of the hardened layer 70 is equal to the outer diameter D3 of the electrode 18 where the edge 74 meets the outer surface 78. In other examples, the outer diameter of the second layer of hardened layer 70 does not extend fully to the diameter D3.

[0041] In some examples, the outer diameter D3 is 0.028”, although other examples include different values and ranges of values (e.g., between 0.026” and .030”, or between 0.02” and 0.04”). As described above, the first hardened layer 62 may include one or more outer diameters DI, D2 (e.g., a single outer diameter or varying outer diameters, depending on the geometry of the first, linear mold 30 that is used). Each ofthe diameters DI, D2 may be less than the outer diameter D3. A difference between the outer diameter D3 and the outer diameter(s) DI, D2, etc. of the first hardened layer 62 defines a wall thickness of the second hardened layer 70. In some examples, the wall thickness of the second hardened layer 70 is at least 0.005”, or is between 0.005” and 0.01”, or is between 0.005 and 0.02”. Other examples include different values and ranges of values.

[0042] With continued reference to FIG. 7, in some examples, the second hardened layer 70 generally forms fillets adjacent the sidewalls 74. A thickness (e.g., radial thickness) of the second hardened layer 70 therefore changes moving along the second hardened layer 70, such that the radial thickness of the second hardened layer 70 is greater adjacent the electrodes 18 than in areas between the electrodes 18.

[0043] With reference to FIG. 8, once the first and second molding steps are complete, the resulting electrode array 10 includes a cross-section (between two of the electrodes 18) in which the electrode wires 22 and the guidewire 26 are at least partially (e.g., fully) encapsulated in the first hardened layer 62, and where the first hardened layer 62 is itself at least partially (e.g., fully) encapsulated in the second hardened layer 70. As seen in FIG. 8, each of the electrode wires 22 may be spaced from one another within the first hardened layer 62. Though eight electrode wires 22 are depicted in the illustrated example (e.g., as a result of FIG. 8 being a cross-section view from plane A-A after which one respective electrode wire 22 terminated at a respective electrode 18), at a proximal- most portion of the second-hardened layer 70 the number of electrode wires 22 would be equal to the number of electrodes 18 on the electrode array 10 (e.g., five electrode wires 22 for five electrodes 18, nine electrode wires 22 for nine electrodes 18, twelve electrode wires 22 for twelve electrodes 18, etc.). Each of the electrode wires 22 may be encapsulated within the first hardened layer 62, and may be encapsulated until it terminates at one of the electrodes 18. Additionally, each of the electrode wires 22 may remain spaced from the guidewire 26. In the illustrated example, the guidewire 26 is generally positioned along one side of the first hardened layer 62, and the electrode wires 22 are generally positioned along another side of the first hardened layer 62. The first hardened layer 62 completely fills in a central region of the electrode array 10, encapsulating the electrode wires 22 and the guidewire 26. In contrast, FIG. 9 illustrates across-section of a different electrode array 10a having a hollow void or cavity 82 (e.g., filled with air), with the electrode wires 22 and the guidewire 26 each passing (e.g., loosely) through the hollow void or cavity 82. The electrode wires 22 and / or the guidewire 26 may contact one another in the hollow void or cavity 82. Utilizing the two- step molding process above, and completely filling in the central region of the electrode array 10 with the first hardened layer 62, allows the electrode wires 22 and the guidewire 26 to be held firmly in place and to become encapsulated in the first hardened layer 62 (e.g., separately from one another), thus inhibiting or preventing any unwanted rubbing or abrasion between the electrode wires 22 and the guidewire 26. In some examples, the arrangement of the two separate hardened layers 62, 70 of polymer, formed by the two- step process, may provide insulative qualities. For example, some embodiments of electrode array 10 may be used to provide high voltage therapy (e.g., electrical pulses of at least IkV), for which manufacturing requires applying voltage of 2X this high voltage (e.g., applying 3kV to the electrode array 10), where this two-step process provides additional insulation reducing the chance of wire damage or shorting. The arrangement of the two hardened layers 62, 70 may also, or alternatively, inhibit any fluid or blood ingress into the electrode array 10, and / or may otherwise inhibit high levels of strain on the electrode wires 22.

[0044] In some examples, the arrangement of the two hardened layers 62, 70 may also, or alternatively, inhibit the electrode wires 22 from being partially exposed along an exterior of the electrode array 10. For example, and as described above, the electrode wires 22 are first secured and encapsulated in the first (cooled) hardened layer 62. Only then is the second hardened layer 70 formed over the top of the first hardened layer 62, to completely conceal the electrode wires 22. This process inhibits or prevents the electrode wires 22 from moving (e.g., sliding) radially outwardly during the molding process (e.g., through a still warm, un-hardened polymer material) so as to potentially be exposed along an exterior of the electrode array 10.

[0045] With reference to FIG. 10, once the first and second molding steps are complete, the electrode array 10 further includes a cross-section (at one of the electrodes 18), in which the electrode wires 22 and the guidewire 26 are again at least partially (e.g., fully) encapsulated in the first hardened layer 62. As seen in FIG. 10, the electrode 18surrounds the first hardened layer 62 at this cross-section, and one of the electrode wires 22 is directly coupled (e.g., welded) to an interior surface 86 (e.g., radially inner) of the electrode 18. The first hardened layer 62 extends around and contacts both the electrode wire 22 and the interior surface 86 at the location of the weld, thereby at least partially (e.g., fully) encapsulating and firmly holding the electrode wire 22 in place even at its connection to the electrode 18. To form this connection, the second molding step may include abutting a portion of the first layer 62 of the molded polymer material against both the interior surface 86 of one of the electrodes 18 and a conductive electrode wire 22 at a location where the conductive electrode wire 22 is welded to the interior surface 86, until the first layer 62 has cooled. In contrast to FIG. 10, FIG. 11 illustrates a cross-section of an electrode array 10b having the hollow void or cavity 82 described above (for the electrode wires 22 and the guidewire 26), and a further hollow void or cavity 90 (e.g., filled with air) at the location of the weld between one of the electrode wires 22 and the electrode 18. Utilizing the two-step molding process above, and completely filling in the central region of the electrode array 10 with the first hardened layer 62, inhibits or prevents formation of this additional hollow void or cavity 90, and allows the electrode wire 22 to be held firmly in place via polymer material, even at its direct (e.g., welded) connection to the electrode 18. Such an arrangement may reduce strain on the electrode wire 22 and the welded connection at this location, and otherwise provide insulative qualities.

[0046] With reference to FIGS. 12 and 13, in some examples, once the first and second molding steps are complete, the resulting electrode array 10 includes an outer profile having a continuous, constant outer diameter that is equivalent to the outer diameter D3 of each electrode 18. For example, during the second molding step, the second hardened layer 70 may be formed such that the polymer material of the second hardened layer 70 extends radially outwardly and evenly, and engages the edges 74 of the electrodes 18 until the polymer material has reached a diameter equal to the outer diameter D3 at all locations of the polymer material between any two electrodes 18. The resulting electrode array 10 thus has electrodes 18 of diameter D3 that are spaced apart from one another along a shared member (e.g., the main body 14), and are exposed along their outer surfaces 78. The electrode array 10 further has a second hardened layer 70 of polymermaterial that extends between each electrode 18 and is, for example, equal in diameter to each electrode 18. In other examples, and as described above, the outer diameter of the second hardened layer 70 may vary between any two electrodes 18. For example, the outer diameter may increase at each electrode 18, and then decrease slightly at a location between the two electrodes 18, such that the overall electrode array 10 includes an outer diameter D3 at each electrode 18, and an outer diameter that fluctuates slightly between each of the electrodes 18.

[0047] With reference to FIGS. 8, 10, 12, and 13, in some examples the electrode array 10 includes no further refinement, crimping, machining, rounding of edges, or use of adhesive to secure and / or seal the electrodes 18 in place. As noted above, the electrodes 18 used with the two-step molding process may be simple, straight-cut electrodes 18, although other examples may use electrodes 18 that are not straight-cut electrodes. In some examples, the use of the two-step molding process may reduce or eliminate extra costs and / or time involved with preparing and forming an electrode array. For example, FIGS. 14 and 15 illustrate electrode arrays 10c and lOd that require additional processes. FIG. 14 illustrates an electrode array 10c in which fillets 94, formed from adhesive, have later been added and applied to seal and / or secure an electrode 18 in place. FIG. 15 illustrates yet a different electrode array lOd in which the edges of the electrode 18 have been rounded, and where the electrode 18 has later been crimped / swaged onto an underlying tube. The electrode array 10 described may be formed without such additional processes. Instead, the two-step molding process itself may secure and / or seal all electrodes 18 in place, in addition to securing all electrode wires 22 and the guidewire 26 in place. In other examples, the electrode array 10 may include additional processes. For example, one or more electrodes 18 may be at least partially crimped / swaged, and / or may include the use of one or more adhesive fillets to help further secure and seal at least one electrode 18.

[0048] The electrode array 10 described herein may be used in various procedures. For example, and with reference to FIG. 16, the electrode array 10 may be used as part of a diagnostic device, for example during atrial fibrillation. FIG. 16 generally illustrates one step of an atrial fibrillation procedure, incorporating the use of a catheter 98 having a cryogenic balloon 102, and an electrode array lOe. The electrode array lOe seenextending from the catheter 98 in FIG. 16 may be replaced by the electrode array 10 described above (i.e., an electrode array formed by the two-step molding process). During atrial fibrillation, the electrode array 10 may detect and measure electrical signals from a pulmonary vein or veins. Those signals may be recorded and mapped, prior to use of the cryogenic balloon 102.

[0049] With reference to FIGS. 17-19, in yet other uses, the electrode array 10 may form part of a single catheter (e.g., loop or lasso catheter) that uses pulsed field ablation (PFA) or radio frequency energy to treat atrial fibrillation. FIGS. 17-19 generally illustrate a catheter 106 and an electrode array lOf. The electrode array lOf may be replaced by the electrode array 10 (i.e., an electrode array formed by the two-step molding process). The electrode array 10 may form part of a single-use, sterile catheter that maps, paces, and / or ablates pulmonary vein(s), and / or performs cardiac tissue ablation through the mechanism of irreversible electroporation.

[0050] The electrode array 10 described above may be used in yet other settings and procedures, other than those illustrated or described. Additionally, and as noted above, the electrode array 10 may include other numbers and spacing of electrodes 18 than that illustrated, and also may include overall shapes other than those illustrated (e.g., other than circular). Furthermore, while the two-step molding process described above has been described and illustrated as having only two steps to form the electrode array 10, in some examples the overall molding process may include more than two steps. For example, the molding process may include additional molding steps (e.g., a third molding step) that introduces yet another outer layer of polymer material, partially or entirely covering the second hardened layer 70.

[0051] In yet other examples, the two molding steps described above may be combined into a single molding step. For example, in some methods the electrode array 10 may be formed by first placing the electrodes 18 and their corresponding electrode wires 22 into the cavity 58 of the second, non-linear mold 38. The guidewire 26 may also be curved and placed into the cavity 58 of the second, non-linear mold 38. Molten polymer material may then be directed into the non-linear cavity 58. The molten polymer material may surround the electrode wires 22 and harden and encapsulate the electrodewires 22 (similar to the first hardened layer 62 described above). The molten polymer material may also surround and harden and encapsulate the guidewire 26. The molten polymer material may also engage a portion of each of the electrodes 18 (e.g., the inner surface 66, and / or a portion of each of the edges 74 of each electrode 18), such that when the molten polymer material hardens, the electrodes 18 are firmly held in a spaced relationship relative to one another. In some examples, fillets may be formed by the hardened polymer material (e.g., similar to those seen in FIG .7), to further secure the electrodes 18 in place.

[0052] It should be understood that various aspects disclosed herein may be combined in different combinations than the combinations specifically presented in the description and accompanying drawings. It should also be understood that, depending on the example, certain acts or events of any of the processes or methods described herein may be performed in a different sequence, may be added, merged, or left out altogether (e.g., all described acts or events may not be necessary to carry out the techniques). In addition, while certain aspects of this disclosure are described as being performed by a single module or unit for purposes of clarity, it should be understood that the techniques of this disclosure may be performed by a combination of units or modules associated with, for example, a medical device.

[0053] The invention may be further described by reference to the following numbered Examples:

[0054] Example 1. An electrode array for a catheter, the electrode array comprising: a plurality of electrodes spaced apart from one another on a shared member of the electrode array: a plurality of conductive electrode wires coupled to the electrodes; a first layer of hardened polymer material formed from a first, linear mold and extending through each of the electrodes, wherein each of the electrode wires is encapsulated within the first layer of hardened polymer material; and a second layer of over-molded, hardened polymer material formed from a second, non-linear mold and extending over and encapsulating a portion of the first layer of hardened polymer material, wherein the second layer of over-molded, hardened polymer material engages each of the electrodes.

[0055] Example 2. The electrode array of Example 1, wherein each of the electrodes is a ring-shaped electrode having a first straight-cut edge at one end of the electrode and a second straight-cut edge at a second end of the electrode.

[0056] Example 3. The electrode array of Example 2, wherein each of the electrodes defines a first outer diameter, wherein the second layer of over-molded, hardened polymer material defines a second outer diameter, wherein the first outer diameter is equal to the second outer diameter at a location of at least one of the first or second straight-cut edges.

[0057] Example 4. The electrode array of Example 3, wherein the second outer diameter remains constant between the electrodes, such that electrode array overall has a continuous, constant outer diameter.

[0058] Example 5. The electrode array of Example 3, wherein the second outer diameter decreases between two of the electrodes, such that the second layer of overmolded, hardened polymer material defines fillets that abut and seal against the two electrodes.

[0059] Example 6. The electrode array of any of the preceding examples, wherein the first layer of hardened polymer material defines an open channel, and wherein a nitinol wire extends through the open channel.

[0060] Example 7. The electrode array of any of the preceding examples, wherein one of the conductive electrode wires is welded to an interior surface of one of the electrodes, wherein the first layer of hardened polymer material engages both the interior surface of the electrode and the electrode wire at a location of the weld.

[0061] Example 8. The electrode array of any of the preceding xamples, wherein each of the plurality of conductive electrode wires is encapsulated within the first layer of hardened polymer material, and is encapsulated until it terminates at one of the electrodes.

[0062] Example 9. The electrode array of any of the preceding examples, wherein the type of material used for the first layer of hardened polymer material isidentical to the type of material used for the second layer of over-molded, hardened polymer material.

[0063] Example 10. The electrode array of any of the preceding examples, wherein the non-linear mold is a circular mold.

[0064] Example 11. A mold assembly for forming an electrode array for a catheter, the mold assembly comprising: a first, linear mold for molding a first portion of the electrode array; and a second, non-linear mold for molding a second portion of the electrode array; wherein the first, linear mold includes a first, elongate cavity extending along an axis and sized and shaped to be filled with a first molten polymer material to encapsulate a set of electrode wires in the first molten polymer material, wherein the first, linear mold is further shaped such that the first molten polymer material is configured to pass through a plurality of electrodes of the electrode array; and wherein the second, nonlinear mold includes a second, non-linear cavity sized and shaped to be filled with a second molten polymer material to encapsulate at least a portion of the first polymer material after the first polymer material has hardened, and to engage the plurality of electrodes.

[0065] Example 12. The mold assembly of Example 11, wherein the first, linear mold further includes a mandrel configured to extend linearly along the cavity, wherein the first molten polymer material is configured to flow around mandrel, such that when the mandrel is removed after the first polymer material has hardened, an elongate linear channel is formed.

[0066] Example 13. The mold assembly of Example 11 or Example 12, wherein the non-linear cavity is circular.

[0067] Example 14. An electrode array formed with the mold assembly of any of Examples 11-13.

[0068] Example 15. A method of forming an electrode array, the method comprising: using a first, linear mold to form a first layer of polymer material, wherein the first layer encapsulates a set of electrode wires and extends through a plurality ofelectrodes; and using a second, non-linear mold to form a second, over-molded layer of polymer material, wherein the second layer extends over and encapsulates a portion of the first layer.

[0069] Example 16. The method of Example 15, further comprising inserting a mandrel into the first, linear mold and using the mandrel to form an open channel extending through the first layer.

[0070] Example 17. The method of Example 16, further comprising inserting a nitinol wire through the open channel, prior to the step of using the second, non-linear mold.

[0071] Example 18. The method of any of Examples 15-17, wherein the step of forming the first layer of polymer material includes abutting a portion of the first layer of polymer material against both an inner surface of one of the electrodes and a conductive electrode wire at a location where the conductive electrode wire is welded to the inner surface.

[0072] Example 19. The method of any of Examples 15-18, wherein the step of forming the second layer of polymer material includes forming the second layer to have an outer diameter that is equal to an outer diameter of one of the electrodes.

[0073] Example 20. The method of any of Examples 15-19, wherein the outer diameter of the second layer is constant along the electrode array, such that the electrode array includes a continuous, constant outer diameter.

[0074] Although various aspects and examples have been described in detail with reference to certain examples illustrated in the drawings, variations and modifications exist within the scope and spirit of one or more independent aspects described and illustrated.

Claims

CLAIMSWhat is claimed is:

1. An electrode array for a catheter, the electrode array comprising: a plurality of electrodes spaced apart from one another on a shared member of the electrode array: a plurality of conductive electrode wires coupled to the electrodes; a first layer of hardened polymer material formed from a first, linear mold and extending through each of the electrodes, wherein each of the electrode wires is encapsulated within the first layer of hardened polymer material; and a second layer of over-molded, hardened polymer material formed from a second, non-linear mold and extending over and encapsulating a portion of the first layer of hardened polymer material, wherein the second layer of over-molded, hardened polymer material engages each of the electrodes.

2. The electrode array of claim 1, wherein each of the electrodes is a ring-shaped electrode having a first straight-cut edge at one end of the electrode and a second straightcut edge at a second end of the electrode.

3. The electrode array of claim 2, wherein each of the electrodes defines a first outer diameter, wherein the second layer of over-molded, hardened polymer material defines a second outer diameter, wherein the first outer diameter is equal to the second outer diameter at a location of at least one of the first or second straight-cut edges.

4. The electrode array of claim 3, wherein the second outer diameter remains constant between the electrodes, such that electrode array overall has a continuous, constant outer diameter.

5. The electrode array of claim 3, wherein the second outer diameter decreases between two of the electrodes, such that the second layer of over-molded, hardened polymer material defines fillets that abut and seal against the two electrodes.

6. The electrode array of any of the preceding claims, wherein the first layer of hardened polymer material defines an open channel, and wherein a nitinol wire extends through the open channel.

7. The electrode array of any of the preceding claims, wherein one of the conductive electrode wires is welded to an interior surface of one of the electrodes, wherein the first layer of hardened polymer material engages both the interior surface of the electrode and the electrode wire at a location of the weld.

8. The electrode array of any of the preceding claims, wherein each of the plurality of electrode wires is encapsulated within the first layer of hardened polymer material, and is encapsulated until it terminates at one of the electrodes.

9. The electrode array of any of the preceding claims, wherein the type of material used for the first layer of hardened polymer material is identical to the type of material used for the second layer of over-molded, hardened polymer material.

10. The electrode array of any of the preceding claims, wherein the non-linear mold is a circular mold.

11. A mold assembly for forming the electrode array of any of claims 1-10, the mold assembly comprising: a first, linear mold for molding a first portion of the electrode array; and a second, non-linear mold for molding a second portion of the electrode array; wherein the first, linear mold includes a first, elongate cavity extending along an axis and sized and shaped to be filled with a first molten polymer material to encapsulate a set of electrode wires in the first molten polymer material, wherein the first, linear mold is further shaped such that the first molten polymer material is configured to pass through a plurality of electrodes of the electrode array; and wherein the second, non-linear mold includes a second, non-linear cavity sized and shaped to be filled with a second molten polymer material to encapsulate at least a portionof the first polymer material after the first polymer material has hardened, and to engage the plurality of electrodes.

12. The mold assembly of claim 11, wherein the first, linear mold further includes a mandrel configured to extend linearly along the cavity, wherein the first molten polymer material is configured to flow around the mandrel, such that when the mandrel is removed after the first polymer material has hardened, an elongate linear channel is formed.

13. The mold assembly of claim 11 or claim 12, wherein the non-linear cavity is circular.

14. An electrode array formed with the mold assembly of any of claims 11-13.

15. A method of forming the electrode array of any of claims 1-10, the method comprising: using a first, linear mold to form a first layer of polymer material, wherein the first layer encapsulates a set of electrode wires and extends through a plurality of electrodes; and using a second, non-linear mold to form a second, over-molded layer of polymer material, wherein the second layer extends over and encapsulates a portion of the first layer.

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