Apparatus for catheter-based electrophysiology

Abstract

The present disclosure provides a flexible circuit strip for use in a catheter assembly. The flexible circuit strip includes a first insulating layer, a second insulating layer, and a third insulating layer, each having an elongated shape and bonded together such that the second insulating layer is between the first insulating layer and the third insulating layer; a conductive trace layer positioned between the first insulating layer and the second insulating layer, the conductive trace layer including a longitudinal circuit trace for carrying electrical signals; an electrode positioned along a length of an outer surface of the first insulating layer and electrically connected to the circuit trace; and a longitudinal hollow channel formed between any two of the first, second, and third layers, the longitudinal hollow channel configured to receive an elongated support element.

Description

Technical Field

[0001] The subject matter of this disclosure relates generally to the field of medical devices, and more specifically to catheters used in electrophysiology. Background Technology

[0002] Arrhythmias, such as atrial fibrillation (AF), occur when a region of heart tissue abnormally transmits electrical signals to adjacent tissues. This disrupts the normal cardiac cycle and leads to irregular heartbeats. Certain procedures are used to treat arrhythmias, including surgically disrupting the signal source causing the arrhythmia and interfering with the conduction pathways used for such signals. By selectively ablating heart tissue through the application of energy via a catheter, it can sometimes be possible to stop or alter the propagation of unwanted electrical signals from one part of the heart to another.

[0003] Many current ablation methods in this field tend to utilize radio frequency (RF) electrical energy to heat tissue. Due to operator skill, RF ablation can have certain rare drawbacks, such as an increased risk of thermal cell damage, which can lead to tissue charring, burns, steam bursts, phrenic nerve paralysis, pulmonary vein stenosis, and esophageal fistulas. Cryoablation is an alternative to RF ablation, reducing some of the thermal risks associated with it, but tissue damage can occur due to the extremely low temperature nature of such devices. However, manipulating cryoablation devices and selectively applying cryoablation is generally more challenging than RF ablation; therefore, cryoablation is not feasible in certain anatomical geometries accessible by electroablation devices.

[0004] Some ablation methods use irreversible electroporation (IRE) to ablate cardiac tissue using non-thermal ablation methods. IRE delivers short pulses of high voltage to the tissue and generates irreversible cell membrane permeability. The use of multi-electrode catheters to deliver IRE energy to tissue has been previously disclosed in patent literature. Examples of systems and devices configured for IRE ablation are disclosed in U.S. Patent Publications Nos. 2021 / 0169550A1, 2021 / 0169567A1, 2021 / 0169568A1, 2021 / 0161592A1, 2021 / 0196372A1, 2021 / 0177503A1, and 2021 / 0186604A1.

[0005] Areas of cardiac tissue can be mapped using catheters to identify abnormal electrical signals. Ablation can be performed using the same or different catheters. Some example catheters include multiple ridges with electrodes mounted thereon. The electrodes are typically attached to the ridges and secured in place by brazing, welding, or using adhesives. Furthermore, multiple linear ridges are often assembled together to form a spherical basket by attaching the two ends of the linear ridges to a tubular shaft (e.g., a propulsion tube). However, due to the small size of the ridges and electrodes, attaching the electrodes to the ridges and then forming the spherical basket from multiple linear ridges can be a challenging task, increasing manufacturing time and cost, and increasing the chance of electrode failure due to improper bonding or misalignment. Therefore, what is needed are devices and methods for forming improved basket assemblies, which can generally help reduce the time required to manufacture basket assemblies, alternative catheter geometries, and alternative electrode shapes and sizes.

[0006] U.S. Patent Application Publication No. 2010 / 0305420 A1 discloses a flexible circuit comprising conductive material on the top and bottom flat surfaces of a dielectric substrate. The flexible circuit can be used in a variety of applications, including as a sensor. Through-holes are used to provide electrical communication between the top and bottom surfaces of the flexible circuit. The invention also provides a method for fabricating the flexible circuit and a medical device including the flexible circuit.

[0007] U.S. Patent No. 9,171,794 B2 provides a system and method for embedding a thin chip. A recessed region is formed in a substrate comprising a conductive material disposed on a flexible polymer. The support recessed region can be formed by patterning the conductive material, in which the thin chip is embedded. A cavity can be formed in a polymer layer to form a polymer recessed region, in which the thin chip is embedded.

[0008] U.S. Patent No. 10,362,953 B2 discloses a conduit having an electrode array formed by an interconnecting frame. The frame may have multiple elements interconnected by multiple junctions located midway between the proximal and distal ends of the electrode array assembly. The electrodes may be printed on a polymer layer of the interconnecting frame.

[0009] U.S. Patent No. 10,297,572 B2 discloses flexible interconnects, flexible integrated circuit systems and apparatuses, and methods for manufacturing and using flexible integrated circuits. A flexible integrated circuit system is disclosed, comprising a first discrete device and a second discrete device electrically connected via discrete flexible interconnects. The first discrete device includes a first flexible multilayer integrated circuit (IC) package having a first electrical connection pad on its outer surface. The second discrete device includes a second flexible multilayer integrated circuit (IC) package having a second electrical connection pad on its outer surface. The discrete flexible interconnects are attached to the first electrical connection pad of the first discrete device and electrically connect the first electrical connection pad of the first discrete device to the second electrical connection pad of the second discrete device.

[0010] U.S. Patent No. 10,681,805 B2 provides an improved flexible circuit structure, for example, by providing a fault-tolerant electrical path for current to flow through the flexible circuit structure. In some embodiments, such fault tolerance is enhanced by means of a conductive mesh provided between a pair of adjacent resistive elements. Some aspects relate to improved voltage, current, or voltage and current measurements associated with each pair of adjacent resistive elements, at least when there are different distances between each pair of adjacent resistive elements.

[0011] U.S. Patent No. 9,159,635 B2 discloses a flexible electronic structure and a method for manufacturing the flexible electronic structure. An example method includes applying a first layer to a substrate, creating a plurality of through-holes through the first layer to the substrate, and applying a second polymer layer to the first layer such that the second polymer forms an anchor that contacts at least a portion of the substrate. At least one electronic device layer is disposed on a portion of the second polymer layer. At least one trench is formed through the second polymer layer to expose at least a portion of the first layer. At least a portion of the first layer is removed by exposing the structure to a selective etchant to provide a flexible electronic structure in contact with the substrate. The electronic structure can be released from the substrate. Summary of the Invention

[0012] This disclosure addresses the technical challenges associated with manufacturing catheters used in catheter-based electrophysiology, specifically for mapping and ablation procedures. Electrophysiology catheters typically include expandable end effectors comprising flexible splines that expand to form a basket shape. Current methods for manufacturing such flexible splines involve laminating the flexible circuit splines onto elongated flexible support members, such as nitinol, and using heat-shrink tubing. These processes become increasingly complex and expensive when dealing with shaped nitinol or other materials with complex three-dimensional geometries. Specifically, conventional methods are prone to problems such as improper bonding, misalignment, and the need for costly and labor-intensive steps, such as laser ablation to create openings for subsequent electrode exposure using shrink tubing.

[0013] The subject matter disclosed in this invention proposes forming a flexible circuit strip with an integrated longitudinal hollow channel during the manufacturing process. This channel is designed to accommodate elongated support elements, such as shaped nitinol, without requiring numerous additional assembly steps after manufacturing. By integrating the channel into the flexible circuit strip, the assembly process is simplified, thereby reducing time and cost while improving the reliability and performance of the final product.

[0014] Specifically, the longitudinal hollow channel can be formed by etching away the conductive layer (e.g., copper) while retaining other conductive elements (such as gold traces and electrodes). The channel is designed to receive elongated support elements, thus allowing for easy assembly. Flexible circuit strips with their integrated channels can accommodate shaped nitinol and other materials with various geometries. Attached Figure Description

[0015] To better understand the subject matter disclosed herein and to illustrate how it can be implemented in practice, examples will now be described by way of non-limiting illustration with reference to the accompanying drawings, wherein: Figure 1 An example of a catheter-based electrophysiological mapping and ablation system according to the subject matter disclosed in this invention is illustrated; Figure 2 An example of a catheter assembly according to this disclosure is illustrated; Figure 3 A top view of a flexible circuit strip according to an example of this disclosure is shown; Figure 4 A cross-sectional view of a flexible circuit strip according to an example of this disclosure is shown; Figures 5A to 5C Views of flexible circuit strips according to other examples of this disclosure are illustrated; Figure 6 The steps of a method for manufacturing a flexible circuit strip according to an example of this disclosure are illustrated. Detailed Implementation

[0016] As used herein, the term “about” or “approximately” for any numerical value or range indicates appropriate dimensional tolerances that allow a collection of parts or components to achieve the intended purpose as described herein. More specifically, “about” or “approximately” may refer to a range of ±20% of the enumerated values, for example, “about 90%” may refer to a range of values ​​from 71% to 99%.

[0017] As discussed herein, the vascular system of the “subject” or “patient” can be that of a human or any animal. It should be understood that the animal can be any applicable type, including but not limited to mammals, veterinary animals, livestock, or pets. For example, the animal can be a laboratory animal specifically selected to possess certain characteristics similar to humans (e.g., rats, dogs, pigs, monkeys, etc.). It should be understood that the subject can be, for example, any applicable human patient.

[0018] As discussed herein, “operator” may include a physician, doctor, surgeon, or any other individual or delivery instrument associated with the delivery of a multi-electrode RF balloon catheter used to treat drug-resistant atrial fibrillation to a subject, and the term “proximal” means the subject is closer to the “operator” and “distal” means the subject is further away from the “operator”.

[0019] As used in the context of circuit strips herein, the term "longitudinal" refers to the direction along the length of the strip from the proximal end to the distal end. The term "lateral" refers to the direction perpendicular to the longitudinal axis, spanning the width of the strip. The term "thickness" refers to the dimension perpendicular to both the longitudinal and lateral directions, indicating the depth of the strip from the top surface (i.e., the top layer) to the bottom surface (the bottom layer).

[0020] In the following detailed description, numerous specific details are set forth in order to provide a comprehensive understanding. However, those skilled in the art will understand that the subject matter disclosed herein can be practiced without these specific details. In other instances, well-known methods and features have not been described in detail so as not to obscure the subject matter disclosed herein.

[0021] refer to Figure 1 This document illustrates an example catheter-based electrophysiological mapping and ablation system 10. System 10 includes multiple catheters inserted by a physician through the skin across the patient's vascular system into a chamber or vascular structure of the heart 12. Typically, a delivery sheath catheter is inserted into the left or right atrium near the desired location within the heart 12. One or more catheters can then be inserted into the delivery sheath catheter to reach the desired location within the heart 12. These multiple catheters may include catheters specifically designed for sensing intracardiac electrogram (IEGM) signals, catheters specifically designed for ablation, and / or catheters specifically designed for both sensing and ablation. An example catheter 14 configured for ablation of tissue and / or for sensing and / or mapping of cardiac electrical activity is illustrated herein.

[0022] The catheter 14 is an exemplary catheter having an end effector at its distal end 28, the end effector comprising an expandable assembly having one, and preferably multiple, electrodes 26 optionally distributed on a plurality of flexible spline elements 24. The electrodes 26 are typically configured to deliver ablation energy to tissue and / or to sense cardiac electrical signals. The catheter 14 further includes one or more position sensors 70 embedded in or near the distal end 28 for tracking the position and orientation of the distal end 28. Optionally and preferably, the position sensors 70 are magnetically based position sensors, such as a position sensor comprising three magnetic coils for sensing three-dimensional (3D) position and orientation; or a position sensor comprising a single magnetic coil for sensing a single orientation.

[0023] Each of the 70 magnetic-based position sensors can operate in conjunction with a positioning pad 25, which includes a plurality of magnetic coils 32 configured to generate a magnetic field in a predefined workspace. The real-time position of the distal end 28 of the conduit 14 can be tracked based on the magnetic field generated by the positioning pad 25 and sensed by the magnetic-based position sensor 70. Details of the magnetic-based position sensing technology are described in U.S. Patents Nos. 5,391,199, 5,443,489, 5,558,091, 6,172,499, 6,239,724, 6,332,089, 6,484,118, 6,618,612, 6,690,963, 6,788,967, and 6,892,091.

[0024] The physician can position the distal end 28 of catheter 14 in contact with the heart wall to sense the target site in the heart 12. Similarly, for ablation, the physician can position the distal end of the ablation catheter in contact with the target site to ablate the tissue.

[0025] System 10 includes one or more electrode patches 38 positioned to contact the skin of patient 23, thereby establishing a position reference for impedance-based tracking of positioning pad 25 and electrodes 26. For impedance-based tracking, current is directed to electrodes 26 and sensed at the electrode skin patch 38, allowing triangulation of the position of each electrode via the electrode patch 38. Details of the impedance-based position tracking technique are described in U.S. Patents 7,536,218, 7,756,576, 7,848,787, 7,869,865, and 8,456,182.

[0026] Recorder 11 records and displays an electrocardiogram 21 captured using ECG electrodes 18 on the body surface and an intracardiac electrocardiogram (IEGM) captured using electrodes 26 on catheter 14. Recorder 11 may include pacing capability for pacing rhythms and / or may be electrically connected to a separate pacemaker.

[0027] System 10 may include an ablation energy generator 50 adapted to conduct ablation energy to one or more electrodes at the distal end of a catheter configured for ablation. The energy generated by the ablation energy generator 50 may include, but is not limited to, radio frequency (RF) energy or pulsed field ablation (PFA) energy (including monopolar or bipolar high-voltage DC pulses that can be used to achieve irreversible electroporation (IRE), or combinations thereof.

[0028] The patient interface unit (PIU) 30 is configured to establish electrical communication between catheters, other electrophysiological equipment, a power supply, and a workstation 55 for operating the system 10. The electrophysiological equipment of the system 10 may include, for example, multiple catheters, positioning pads 25, surface ECG electrodes 18, electrode patches 38, an ablation energy generator 50, and a recorder 11. Optionally and preferably, the PIU 30 further includes processing capabilities for real-time calculation of catheter position and for performing ECG calculations.

[0029] Workstation 55 includes a memory, a processor unit having a memory or storage device storing appropriate operating software, and user interaction capabilities. Workstation 55 may provide several functions, optionally including: (1) three-dimensional (3D) modeling of the endocardial anatomy and rendering the model or anatomical mapping 20 for display on display device 27; (2) displaying on display device 27, in the form of representative visual markers or images superimposed on the rendered anatomical mapping 20, an activation sequence (or other data) compiled from the recorded electrogram 21; (3) displaying the real-time position and orientation of multiple catheters within the cardiac chambers; and (4) displaying on display device 27 sites of interest, such as where ablation energy has been applied. A commercial product embodying elements of system 10 can be marketed under the trade name CARTO. ™ The system was purchased from Biosense Webster, Inc., 31A Technology Drive, Irvine, CA 92618.

[0030] In some examples, a flushing module is provided for delivering flushing fluid, such as a saline solution, to the treatment site. The flushing module may include a pump and an associated fluid tank.

[0031] Now for reference Figure 2This is a schematic diagram of a conduit assembly 100 constructed and operated according to an example of this disclosure. The conduit assembly 100 includes a tubular shaft 140 having a distal end, a connector (also referred to as a spline retaining hub) 160 connected to the distal end 140 of the tubular shaft, and an actuator 180 including a distal portion 200. The actuator 180 can be configured to advance and retract through the tubular shaft, for example using a manipulator or handle (not shown). The actuator 180 can be coaxially disposed within the spline retaining hub and configured to translate relative to its longitudinal direction. The conduit assembly 100 also includes an expandable assembly 220 (also commonly referred to as an expandable end actuator) comprising a plurality of flexible splines 240 (labeled only for simplicity). Each flexible spline 240 includes a flexible circuit strip (PCB) comprising a plurality of electrodes 260 disposed thereon (only some electrodes are labeled for simplicity) and corresponding elongated elastic support elements extending along a given length of the flexible polymer circuit strip. The flexible spline 240 can be coupled at one end to the connector 160 and at the other end to the distal end 200 of the actuator 180, so that actuation of the actuator 180 can selectively expand or retract the expandable assembly 220. Typically, the catheter assembly 100 can be inserted into the delivery sheath (…). Figure 2 (Not shown in the image) so as to reach the desired position in the heart 12. Then, the expandable component 220 can expand when it protrudes from the delivery sheath by actuation of the pusher 180.

[0032] Flexible circuit strips can have any suitable size. For example, the length of a flexible circuit strip can be in the range of 10 mm to 60 mm (e.g., 30 mm), the width of a flexible circuit strip can be in the range of 0.25 mm to 3 mm (e.g., 0.72 mm), and the thickness of a flexible circuit strip can be in the range of 0.005 mm to 0.14 mm.

[0033] In some examples, the electrodes 260 extend to occupy a large portion of the width of the flexible circuit strip that houses them. In some examples, the electrode width is 0.25 mm to 3 mm, and / or the electrode length is 0.25 mm to 3 mm.

[0034] The elongated elastic support element can be provided in the expanded form of the expandable component 220. The elongated elastic support element may include any suitable material, such as, but not limited to, nitinol and / or shaped nitinol and / or polyetherimide (PEI). As explained in further detail herein, the present disclosure may provide corresponding elongated elastic support elements that can extend within the hollow channels of the corresponding flexible circuit strip.

[0035] Electrodes 260 positioned on spline 240 of basket assembly 220 can be configured to determine the location of basket assembly 220 and / or measure physiological characteristics, such as local surface potential at a corresponding location on cardiac tissue. In addition, or alternatively, the electrodes can also be used to deliver ablation energy RF and / or IRE to cardiac tissue. Examples of materials ideally suited for forming electrodes 220 include gold, platinum, and palladium, and their respective alloys.

[0036] In other examples, the conduit assembly may include a tubular shaft having a distal end and a connector attached to the distal end of the tubular shaft. The conduit assembly may also include an expandable component 220 (often also referred to as an expandable end effector) comprising a plurality of flexible splines (labeled only once for simplicity). Each flexible spline may include a flexible circuit strip (PCB) comprising a plurality of electrodes disposed thereon and corresponding elongated elastic support elements extending along a given length of the flexible polymer circuit strip.

[0037] The flexible spline can be attached to connectors (also called spline holding hubs) at both ends and can be configured to expand radially into a basket shape when unconstrained. Typically, a catheter is inserted into a delivery sheath to reach a desired location in the heart. The expandable assembly can then expand as it protrudes from the delivery sheath, i.e., simply by being pushed out of the delivery sheath. In other words, in these other examples, the expandable basket assembly can be configured to change from a collapsed form to an expanded form simply by releasing the radial constraints on the flexible spline. The flexible spline can also be configured to retract when pulled into the delivery sheath.

[0038] The catheter assembly may also include a contact force sensor to determine the contact force of the spline against cardiac tissue. Details of the contact force sensor are shown and described in U.S. Patent Application Publication No. US20210077180A1, published March 18, 2021, the disclosure of which is incorporated herein by reference.

[0039] Now for reference Figure 3 The figure is for example used for Figure 2A schematic diagram of a flexible polymer circuit strip in a conduit assembly 100. The flexible polymer circuit strip 245 may be formed of a polymer, such as polyimide. The circuit strips 245 may be connected to each other via polyimide, or assembled into individual pieces that maintain proper alignment and are secured to the connector 160. A corresponding first end 420 of each flexible polymer circuit strip 245 includes an electrical connection array 600. Illustration 62 shows the electrical connection array 600 including electrical contacts 640 (only some electrical contacts are labeled for simplicity). The electrical contacts 640 are connected via traces (not shown) on one side of the top layer of the flexible polymer circuit strip 245 to corresponding electrodes in electrodes 260 disposed on the other side of the top layer of the flexible polymer circuit strip. Away from the first end 420, the flexible polymer circuit strips 245 are separated from each other to allow the flexible polymer circuit strips 245 to form an expandable assembly 220 when connected to the conduit assembly 100. Figure 2 A wire (not shown) can connect the electrode 260 to a control circuit (not shown) via an electrical contact 640. The wire can be disposed in the lumen (not shown) of an elongated deflectable element.

[0040] In some examples, one or more pads are smaller than the electrode size. The surface area presented by the pads for contact (e.g., via a measuring probe or bonding tool) is smaller than the surface area presented by the electrode. For example, the upper surface area of ​​the pad is 1% to 20% of the electrode surface area. For example, the pad width is 0.05 mm to 0.5 mm, and / or the pad length is 0.1 mm to 1 mm.

[0041] The surface area 620 of the flexible circuit strip on which pads 420 are provided can be small, and / or the density of pads on this area can be high. For example, the proportion of the area with a width of 0.25 mm to 3 mm and a length of 0.5 mm to 6 mm and / or the surface area occupied by pads is 20% to 50%.

[0042] As explained in more detail below, the flexible polymer circuit strip is typically formed of multiple insulating layers, including a top layer (also referred to as the first layer), an intermediate layer (also referred to as the second layer), and a bottom layer (also referred to as the third layer). A conductive trace layer may be positioned between the intermediate insulating layer and the top layer of the flexible polymer circuit strip 245. The conductive trace layer may include circuit traces connecting electrodes 260 to the connection array 600. The top layer includes electrodes 260 and optionally one or more contact pads. The circuit traces on the intermediate layer may connect each electrode 260 to a corresponding electrical contact 640 using through-holes (not shown). The circuit traces of the electrodes 260 may be in the range of about 0.005 mm to 0.1 mm in width (e.g., 0.025 mm), wherein the spacing is in the range of about 0.005 mm to 0.1 mm (e.g., 0.025 mm). The thickness of the traces may be in the range of about 0.005 mm to 0.100 mm (e.g., 0.010 mm). In some embodiments, the circuit traces may have the same width and spacing.

[0043] Figure 4 A cross-sectional view of a flexible circuit strip 245 according to an example of the present disclosure is illustrated. The flexible circuit strip 245 may include a (top) first insulating layer 241, a second (middle) insulating layer 242, and a third (bottom) insulating layer 243. The first insulating layer 241, the second insulating layer 242, and the third insulating layer 243 may be formed of a polymer (such as polyimide). The first insulating layer 241, the second insulating layer 242, and the third insulating layer 243 may have an elongated shape to form the circuit strip. The first insulating layer 241, the second insulating layer 242, and the third insulating layer 243 may have corresponding lateral and longitudinal dimensions, such that they can be properly aligned and registered with each other, for example, during lamination. The thickness of the first insulating layer 241 may be greater than that of either the second insulating layer 242 or the third insulating layer 243.

[0044] The proximal end of the first insulating layer 241 may include, as per [the relevant information] Figure 3 The described electrical connection array (also referred to as a contact array) may be positioned at a proximal end of the outer surface of the first insulating layer 241. Electrode 260 may be positioned along the length of the outer surface of the first insulating layer 241. Electrode 260 may be disposed away from the proximal end of the insulating layer 241. The electrode may be formed of a first conductive material (such as gold).

[0045] The flexible circuit strip 245 may further include a conductive trace layer positioned between the first insulating layer 241 and the second insulating layer 242. The conductive trace layer may include longitudinal circuit traces 247 for carrying electrical signals. The longitudinal circuit traces 247 may be configured to carry electrical signals between the electrodes 260 and the electrical connection array. The electrodes 260 may be connected to the circuit traces 247 using through-holes extending through the first insulating layer 241 and the second insulating layer 242. The conductive circuit traces 247 may be formed of the same first conductive material as the electrodes. In some embodiments, the conductive circuit traces may be formed of a second conductive material different from the first conductive material.

[0046] The flexible circuit strip 245 may also include a longitudinal hollow channel 244 formed between the second insulating layer 242 and the third insulating layer 243 (or, in some other examples, between the first insulating layer and the second insulating layer). The longitudinal hollow channel 244 may be configured to receive an elongated support element (not shown) extending substantially along the entire length of the flexible circuit strip. The elongated support element may be formed of a resilient material and may include, for example, nitinol / or shaped nitinol / or polyetherimide (PEI). The elongated support element may be arranged in the longitudinal hollow channel with gaps, thereby allowing longitudinal adjustment therein. The elongated support element may be adhered to the longitudinal hollow channel using epoxy resin to provide limited adhesion, thereby allowing residual longitudinal gaps. In some examples, the elongated support element may be adhered to secure it within the longitudinal channel. The longitudinal hollow channel may have a constant cross-sectional geometry. The cross-sectional shape of the longitudinal hollow channel may be trapezoidal, rectangular, circular, or elliptical. In some examples, the longitudinal hollow channel may have a variable cross-section along the length of the flexible circuit strip and may be configured to accommodate elongated support elements with varying diameters. In some examples, the longitudinal hollow channel may include reinforcing features to enhance the structural integrity of the flexible circuit strip.

[0047] For reference Figure 6 To explain in more detail, the longitudinal hollow channel 244 can be created by etching away the conductive channel layer covering the surface of the second insulating layer facing the third insulating layer. The conductive channel layer can be formed of a third conductive material (e.g., copper) different from the first and / or second conductive materials. This allows the covering conductive layer to be etched away while preserving the electrodes and / or circuit traces.

[0048] Figures 5A to 5C A view illustrating a flexible circuit strip 245' according to an example of this disclosure is shown. Figures 5A to 5C In the figures, the same reference numerals are used to indicate references to figures previously described. Figure 4 Similar to those components in [the original text]. For the sake of brevity, detailed descriptions of these components will not be repeated here. Only additions or differences will be described in detail. For example... Figures 5A to 5CAs illustrated, the flexible circuit strip 245' also includes a plurality of insulating covers 270, each covering a plurality of electrodes 260. The insulating covers 270 may include one or more openings 275. The insulating covers 270 may be positioned over the electrodes 260 to expose selected portions of the electrodes 260. The one or more openings 275 may have a semi-circular shape to expose semi-circular portions of the electrodes. In some examples, selected portions of the electrodes may be positioned at the lateral edges of the electrodes 260.

[0049] refer to Figure 4 and Figures 5A to 5C The flexible circuit strips 245 and 245' described above can be adapted for integration into the reference above. Figure 2 The detailed end effector and conduit assembly. Specifically, the flexible spline 240 described above may include circuit strips 245, 245', and elongated support elements may be disposed in the longitudinal hollow channels 244 of the circuit strips 245, 245'.

[0050] Figure 6 The steps of a method for manufacturing a flexible circuit strip according to an example of this disclosure are illustrated. In a first step S100, an elongated multilayer laminate 300 may be provided. The multilayer laminate 300 may include an insulating layer 310 formed of a flexible polymer (such as polyimide), a conductive channel layer 340 covering the insulating layer 310 formed of a conductive material (such as copper), an adhesive layer 330 formed of an adhesive (such as epoxy resin), and another insulating layer 320 formed of a polymer (such as polyimide). In a second step S200, the multilayer laminate 300 may be drilled to form an opening 350 through the other polymer layer 320 and the adhesive layer 330 to expose the conductive channel layer 340. This step may be performed using precision drilling techniques (such as laser drilling or mechanical drilling) to ensure accuracy and consistency. In a third step S300, the conductive channel layer 340 may be etched to form longitudinally hollow channels in the elongated multilayer laminate 300. Etching processes may involve chemical etching using an etchant solution that selectively removes conductive material (e.g., copper) from conductive channels while retaining other conductive material (e.g., gold traces and / or electrodes) optionally present on the laminate, or plasma etching for more precise control.

[0051] The method described herein can be used to form longitudinal hollow channels in flexible circuit strips, as described above. Insulating layers 310 and 320 may correspond to the intermediate and bottom insulating layers as previously described. The resulting hollow channels can be configured to accommodate elongated support elements, such as nitinol wires. Example

[0052] The following is a non-exclusive list of some exemplary embodiments of this disclosure. This disclosure also includes embodiments that include fewer than all features of the embodiments, as well as embodiments that use features from multiple embodiments, even if not listed below.

[0053] Example 1 A flexible circuit strip (245) for use in a conduit assembly (100), the flexible circuit strip comprising: (a) A first insulating layer (241), a second insulating layer (242) and a third insulating layer (243), each having an elongated shape and being joined together such that the second insulating layer is located between the first insulating layer and the third insulating layer; (b) A conductive trace layer positioned between the first insulating layer and the second insulating layer, the conductive trace layer including longitudinal circuit traces (247) for carrying electrical signals. (c) Electrode (260), which is positioned along the length of the outer surface of the first insulating layer and electrically connected to the circuit trace; (d) A longitudinal hollow channel (244) formed between any two of the first layer, the second layer and the third layer (241, 242, 243), the longitudinal hollow channel (244) being configured to receive an elongated support element.

[0054] Example 2 According to the flexible circuit strip (245) of Embodiment 1, the flexible circuit strip further includes a contact array (600) located at the proximal end of the outer surface of the first insulating layer (241), wherein the electrode (260) is connected to the contact array (600) using the circuit trace (247).

[0055] Example 3 According to the flexible circuit strip (245) of Embodiment 2, the connection between the circuit trace (247) and the electrode (260) is established through a through hole extending through the first insulating layer (241).

[0056] Example 4 According to any of the preceding embodiments, the flexible circuit strip (245) wherein each electrode (260) is covered by an insulating cap (270) including one or more openings (275), the insulating cap (270) being positioned above the electrode (260) to expose selected portions of the electrode (260).

[0057] Example 5 The flexible circuit strip (245) according to any one of the foregoing embodiments, wherein the electrode (260) and the circuit trace (247) contain gold.

[0058] Example 6 The flexible circuit strip (245) according to any one of the foregoing embodiments, wherein the first insulating layer, the second insulating layer and the third insulating layer (241, 242, 243) comprise polyimide.

[0059] Example 7 The flexible circuit strip (245) according to any one of the foregoing embodiments, wherein the conductive channel layer comprises gold.

[0060] Example 8 According to any one of the foregoing embodiments, the flexible circuit strip (245) is thicker than the second insulating layer (241) and the third insulating layer (242, 243).

[0061] Example 9 An expandable end effector (220) for use in a catheter assembly (100) includes: (a) Spline holding hub (160); (b) An expandable basket assembly (220) coupled to the spline holding hub (160), the expandable basket assembly (220) including one or more flexible splines (240) coupled to the spline holding hub (160) and configured to bend radially outward from a collapsed form to an expanded form, each flexible spline (240) including: i. The flexible circuit strip (245) according to any one of the foregoing embodiments; ii. An elongated support element disposed in the longitudinal hollow channel (244).

[0062] Example 10 According to the expandable end effector of Embodiment 9, the elongated support member is arranged to have a gap within the longitudinal hollow channel (244), thereby allowing longitudinal adjustment in the longitudinal hollow channel.

[0063] Example 11 According to the expandable end effector of Embodiment 9, the elongated support member is fixed within the longitudinal hollow channel (244).

[0064] Example 12 According to any one of embodiments 9 to 11, the expandable end actuator includes a first flexible spline having a proximal end connected to the spline holding hub (160) and a distal end of the first flexible spline connected to a distal end of a second flexible spline.

[0065] Example 13 According to any one of embodiments 9 to 11, the expandable end actuator further includes a pusher (180) coaxially disposed within the spline retaining hub (160) and configured to translate relative to the spline retaining hub along the longitudinal axis of the hub; each of the one or more flexible splines (240) has a proximal end connected to the spline retaining hub (160) and a distal end connected to the distal end of the pusher (180), the one or more flexible splines (240) being configured to bend radially outward when the pusher (180) retracts relative to the spline retaining hub (160), thereby causing the expandable basket assembly (220) to expand from a collapsed form to an expanded form.

[0066] Example 14 According to any one of embodiments 9 to 11, the expandable end effector wherein the one or more flexible splines (240) are configured to bend radially outward when the radial constraint is released.

[0067] Example 15 According to the expandable end effector of embodiment 14, the one or more flexible splines (240) include a proximal end and a distal end, both of which are connected to the spline retaining hub (160).

[0068] Example 16 According to any one of embodiments 9 to 15, the expandable end effector includes a plurality of flexible splines (240) that expand to form a basket shape.

[0069] Example 17 According to any one of embodiments 9 to 16, the expandable end actuator is wherein the elongated support element is fitted into the longitudinal hollow channel (244) and loosely secured with adhesive to have a longitudinal gap.

[0070] Example 18 According to any one of embodiments 9 to 17, the expandable end effector, wherein the elongated support element comprises shaped nitinol.

[0071] Example 19 A catheter assembly (100) comprising: - A tubular shaft (140) extending along a longitudinal axis that extends from a proximal portion of the tubular shaft (140) to a distal portion of the tubular shaft (140); and - An expandable end effector according to any one of embodiments 9 to 18.

[0072] Example 20 A method for manufacturing a flexible circuit strip according to any one of embodiments 1 to 8, the method comprising: (a) Provide (S100) an elongated multilayer composite (300), wherein the multilayer composite includes an insulating layer (310) comprising a flexible polymer, a conductive channel layer (340) covering the insulating layer (310) and comprising a conductive material, an adhesive layer (330) and another insulating layer (320) comprising the flexible polymer. (b) Drilling the multilayer composite (300) to form an opening (350) through the other polymer layer (320) and the adhesive layer (330), thereby exposing the conductive channel layer (340). (c) Etch the conductive channel layer (340) to form a longitudinal hollow channel (360) in the elongated multilayer composite (300).

[0073] Those skilled in the art to which this disclosure pertains will understand that, although the invention has been described with reference to preferred embodiments, the concepts upon which this disclosure is based can readily be used as the basis for designing other structures, systems, and processes for achieving some of the objectives of this disclosure.

[0074] Furthermore, it should be understood that the wording and terminology used herein are for illustrative purposes and should not be considered restrictive. It should be noted that the words “comprising,” “including,” and “having” used throughout the appended claims should be interpreted as meaning “including, but not limited to,” unless expressly stated to the contrary. The indefinite articles “a” and “an” as used herein in the specification and claims should be understood as meaning “at least one.” The phrase “and / or” as used herein in the specification and claims should be understood as meaning “any one or both” of the elements so combined, i.e., elements that are combined in some cases and separate in others. The term “each” can be understood non-exclusively to refer to each and every, and may also refer to “at least some” when technically relevant.

[0075] All patents and patent applications mentioned in this specification are incorporated herein by reference in their entirety as if each individual patent or patent application were expressly and independently incorporated herein by reference. Furthermore, any reference or identification in this patent application should not be construed as an admission that such reference is available as prior art in this disclosure.

[0076] Therefore, it is important that the scope of this disclosure not be construed as limited to the exemplary embodiments set forth herein. Other variations are possible within the scope of this disclosure as defined by the appended claims. Other combinations and sub-combinations of features, functions, elements, and / or characteristics may be claimed by amendments to these claims or by setting forth new claims in this application or related applications. Whether for different combinations or for the same combination, these amended or new claims, whether different, broader, narrower, or identical in scope to the original claims, are considered to be included within the subject matter of this specification.

Claims

1. A flexible circuit strip for use in a conduit assembly, the flexible circuit strip comprising: (a) A first insulating layer, a second insulating layer and a third insulating layer, each insulating layer having an elongated shape and being joined together such that the second insulating layer is located between the first insulating layer and the third insulating layer; (b) A conductive trace layer, the conductive trace layer being positioned between the first insulating layer and the second insulating layer, the conductive trace layer including longitudinal circuit traces for carrying electrical signals; (c) Electrode, which is positioned along the length of the outer surface of the first insulating layer and electrically connected to the circuit trace; (d) A longitudinal hollow channel formed between any two of the first layer, the second layer and the third layer, the longitudinal hollow channel being configured to receive an elongated support element.

2. The flexible circuit strip according to claim 1, further comprising an array of contacts positioned at the proximal end of the outer surface of the first insulating layer, wherein, The electrodes are connected to the contact array using the circuit traces.

3. The flexible circuit strip according to claim 2, wherein, The connection between the circuit trace and the electrode is established through a via extending through the first insulating layer.

4. The flexible circuit strip according to claim 1, wherein, Each electrode is covered by an insulating cap that includes one or more orifices, the insulating cap being positioned above the electrode to expose selected portions of the electrode.

5. The flexible circuit strip according to claim 1, wherein, The electrodes and the circuit traces contain gold.

6. The flexible circuit strip according to claim 1, wherein, The first insulating layer, the second insulating layer, and the third insulating layer comprise polyimide.

7. The flexible circuit strip according to claim 1, wherein, The conductive trace layer contains gold.

8. The flexible circuit strip according to claim 1, wherein, The first insulating layer is thicker than the second insulating layer and the third insulating layer.

9. An expandable end effector for use in a catheter assembly, the expandable end effector comprising: (a) Spline retaining hub; (b) An expandable basket assembly coupled to the spline holding hub, the expandable basket assembly comprising one or more flexible splines coupled to the spline holding hub and configured to bend radially outward from a collapsed form to an expanded form, each flexible spline comprising: iii. A flexible circuit strip, said flexible circuit strip comprising: - A first insulating layer, a second insulating layer and a third insulating layer, each insulating layer having an elongated shape and being joined together such that the second insulating layer is located between the first insulating layer and the third insulating layer; - A conductive trace layer, the conductive trace layer being positioned between the first insulating layer and the second insulating layer, the conductive trace layer including longitudinal circuit traces for carrying electrical signals; - An electrode, which is positioned along the length of the outer surface of the first insulating layer and electrically connected to the circuit trace; - A longitudinal hollow channel formed between any two of the first insulating layer, the second insulating layer and the third insulating layer, the longitudinal hollow channel being configured to receive an elongated support element; iv. An elongated support element disposed in the longitudinal hollow channel.

10. The expandable end effector according to claim 9, wherein, The elongated support element is arranged to have a gap within the longitudinal hollow channel, thereby allowing longitudinal adjustment within the longitudinal hollow channel.

11. The expandable end effector according to claim 9, wherein, The slender support element is fixed inside the longitudinal hollow channel.

12. The expandable end effector according to claim 9, wherein, The expandable basket assembly includes a first flexible spline having a proximal end connected to the spline holding hub, and a distal end of the first flexible spline being connected to a distal end of a second flexible spline.

13. The expandable end effector of claim 9, further comprising a pusher coaxially disposed within the spline retaining hub and configured to translate relative to the spline retaining hub along a longitudinal axis of the hub; each of the one or more flexible splines having a proximal end connected to the spline retaining hub and a distal end connected to the distal end of the pusher, the one or more flexible splines being configured to bend radially outward when the pusher retracts relative to the spline retaining hub, thereby causing the expandable basket assembly to expand from a collapsed form to an expanded form.

14. The expandable end effector according to claim 9, wherein, The one or more flexible splines are configured to bend radially outward when the radial constraint is released.

15. The expandable end effector according to claim 14, wherein, The one or more flexible splines include a proximal end and a distal end, both of which are connected to the spline holding hub.

16. The expandable end effector of claim 9, wherein the expandable end effector comprises a plurality of flexible splines forming a basket shape in the expanded form.

17. The expandable end effector according to claim 9, wherein, The elongated support element is assembled into the longitudinal hollow channel and loosely secured with adhesive to allow for longitudinal clearance.

18. The expandable end effector according to claim 9, wherein, The elongated support element comprises shaped nitinol.

19. A catheter assembly comprising: - A tubular shaft extending along a longitudinal axis that extends from a proximal portion of the tubular shaft to a distal portion of the tubular shaft; and - An expandable end effector, the expandable end effector comprising: (a) A spline retaining hub, the spline retaining hub being connected to the distal portion of the tubular shaft; (b) An expandable basket assembly coupled to the spline holding hub, the expandable basket assembly comprising one or more flexible splines coupled to the spline holding hub and configured to bend radially outward from a collapsed form to an expanded form, each flexible spline comprising: i. A flexible circuit strip, said flexible circuit strip comprising: - A first insulating layer, a second insulating layer and a third insulating layer, each insulating layer having an elongated shape and being joined together such that the second insulating layer is located between the first insulating layer and the third insulating layer; - A conductive trace layer, the conductive trace layer being positioned between the first insulating layer and the second insulating layer, the conductive trace layer including longitudinal circuit traces for carrying electrical signals; - An electrode, which is positioned along the length of the outer surface of the first insulating layer and electrically connected to the circuit trace; - A longitudinal hollow channel formed between any two of the first insulating layer, the second insulating layer and the third insulating layer, the longitudinal hollow channel being configured to receive an elongated support element; ii. An elongated support element disposed in the longitudinal hollow channel.

20. A method for manufacturing a flexible circuit strip, the method comprising: (a) Providing an elongated multilayer composite, wherein the multilayer composite includes an insulating layer comprising a flexible polymer, a conductive channel layer covering the insulating layer and comprising a conductive material, an adhesive layer, and another insulating layer comprising the flexible polymer; (b) Drilling the multilayer composite to form an opening through the other polymer layer and the adhesive layer to expose the conductive channel layer; (c) Etching the conductive channel layer to form a longitudinal hollow channel in the elongated multilayer composite.

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