High-density electrode mapping catheter

Abstract

An integrated electrode structure may include a catheter shaft having a proximal end and a distal end, the catheter shaft defining a longitudinal axis. A flexible tip portion may be positioned adjacent to the distal end of the catheter shaft, the flexible tip portion comprising a flexible frame. A plurality of microelectrodes may be positioned on the flexible frame and may form a flexible microelectrode array adapted to conform to tissue. A plurality of conductive traces may be positioned on the flexible frame, each of the plurality of conductive traces being electrically connected to a corresponding one of the plurality of microelectrodes.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is a continuation-in-part of U.S. application No. 15 / 331,562 (Serial No. 562), filed on October 21, 2016, now pending. This application claims priority to U.S. application No. 62 / 244,565 (Serial No. 565), filed on October 21, 2015. This application claims priority to U.S. application No. 62 / 324,067 (Serial No. 067), filed on April 18, 2016. Applications No. 562, No. 565, and No. 067 are incorporated herein by reference as if fully set forth herein. This application relates to U.S. application No. 16 / 781,499 (Serial No. 499), entitled “High-density electrode mapping catheter,” filed on February 4, 2020, now pending. This application is related to U.S. Application No. 15 / 331,369 ('369'), entitled "High Density Electrode Mapping Catheter," filed on October 21, 2016, which now issued as U.S. Patent No. 10,362,954 on July 30, 2019. Both the '499 and '369 applications are incorporated herein by reference as if fully set forth herein. Technical Field

[0003] The present disclosure relates to a high-density electrode mapping catheter. Background Art

[0004] Catheters have been used in cardiac medical procedures for many years. For example, they can be used to diagnose and treat heart arrhythmias when located in specific locations within the body that are inaccessible without invasive surgery.

[0005] Conventional mapping catheters, for example, may include a plurality of adjacent ring electrodes that surround the longitudinal axis of the catheter and are constructed of platinum or some other metal. These ring electrodes are relatively rigid. Similarly, conventional ablation catheters may include a relatively rigid tip electrode for delivering therapy (e.g., delivering radiofrequency (RF) ablation energy) and may also include a plurality of adjacent ring electrodes. When employing these conventional catheters and their relatively rigid (or non-conforming), metallic electrodes, it may be difficult to maintain good electrical contact with cardiac tissue, particularly in the presence of sharp gradients and undulations.

[0006] Whether mapping or creating lesions in the heart, an erratic or irregular heartbeat complicates matters, making it difficult to maintain adequate contact between electrodes and tissue for a sufficient period of time. These issues are exacerbated on curved or tortuous surfaces. If contact between electrodes and tissue cannot be adequately maintained, it is impossible to create a high-quality lesion or accurately map it.

[0007] The above discussion is intended only to illustrate the prior art and should not be construed as a disclaimer of the scope of the claims. Summary of the Invention

[0008] Various embodiments herein provide an integrated electrode structure. In at least one embodiment, the integrated electrode structure may include a catheter shaft comprising a proximal end and a distal end, wherein the catheter shaft defines a longitudinal axis of the catheter shaft. A flexible tip portion is located near the distal end of the catheter shaft, wherein the flexible tip portion includes a flexible frame. A plurality of microelectrodes are located on the flexible frame and form a flexible microelectrode array adapted to conform to tissue; a plurality of conductive traces may be located on the flexible frame, each of the plurality of conductive traces being electrically connected to each of the plurality of microelectrodes.

[0009] Various embodiments herein provide a method for forming an integrated electrode structure. In at least one embodiment, the method includes coating a flexible frame of a flexible head end portion of the integrated electrode structure with a first dielectric material. The method may include masking a trace pattern on the coated flexible frame using a masking material to form a masked portion and an unmasked trace pattern portion. The method may include depositing a seed layer on the unmasked trace pattern portion, and the method may include electroplating the seed layer with a conductive material to form a conductive trace. The method may include stripping the masking material from the masking portion. The method may include coating the conductive trace with a second dielectric material. The method may include stripping the second dielectric material from a distal portion of the conductive trace. The method may include electrically connecting a microelectrode to the distal portion of the conductive trace.

[0010] Various embodiments herein provide a method for forming an integrated electrode structure. In at least one embodiment, the method includes coating a flexible frame substrate of a flexible head end portion of the integrated electrode structure with a conductive material. The method may include masking a trace pattern on the coated flexible frame using a masking material to form a masked trace pattern portion and an unmasked portion. The method may include etching the unmasked portion to expose the flexible frame substrate. The method may include stripping the masking material from the masked trace pattern portion to expose the conductive trace. The method may include coating the conductive trace with a dielectric material. The method may include stripping the dielectric material from a distal portion of the conductive trace. The method may include electrically connecting a microelectrode to the distal portion of the conductive trace.

[0011] Various embodiments herein provide an integrated electrode structure comprising a catheter shaft including a proximal end and a distal end, the catheter shaft defining a longitudinal axis of the catheter shaft. A flexible head portion may be located adjacent to the distal end of the catheter shaft, the flexible head portion comprising a flexible frame including an inner lower structure and an outer lower structure. A plurality of microelectrodes may be located on the top surfaces of the inner lower structure and the outer lower structure and on the bottom surfaces of the inner lower structure and the outer lower structure, forming a flexible microelectrode array suitable for conforming to tissue. A plurality of conductive traces may be located on the top surfaces of the inner lower structure and the outer lower structure and on the bottom surfaces of the inner lower structure and the outer lower structure, each of the plurality of conductive traces being electrically connected to a corresponding one of the plurality of microelectrodes.

[0012] Various embodiments herein provide a method for determining the extent of contact between a first electrode and tissue. In some embodiments, the method may include receiving a first electrical signal from the first electrode located on a first side of a head portion of a medical device. In some embodiments, the method may include receiving a second electrical signal from the second electrode located on a second side of the head portion of the medical device; wherein the first electrode and the second electrode are positioned vertically adjacent to each other. In some embodiments, the method may include determining the extent of contact between the first electrode and the tissue based on a comparison between the first electrical signal and the second electrical signal.

[0013] Various embodiments herein provide a method for determining cardiac excitation associated with endocardial tissue. The method may include receiving a first electrical signal from a first electrode located on a first side of a head portion of a medical device. In some embodiments, the method may include receiving a second electrical signal from a second electrode located on a second side of the head portion of the medical device, wherein the first electrode and the second electrode are positioned vertically adjacent to each other. In some embodiments, the method may include determining a characteristic associated with the cardiac excitation, wherein the cardiac excitation is located in a direction perpendicular to a surface of the endocardial tissue. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1A A top view of a high-density electrode mapping catheter according to various embodiments of the present disclosure is shown.

[0015] Figure 1B The present invention shows various embodiments of the present invention. Figure 1A Isometric side and top views of the mapping catheter with medium and high density electrodes.

[0016] Figure 2A The present invention shows various embodiments of the present invention. Figure 1AIsometric side and top views of the medial substructure of the medium and high density electrode mapping catheter.

[0017] Figure 2B Isometric side and top views of a coated inner substructure of a high-density electrode mapping catheter are shown, according to various embodiments of the present disclosure.

[0018] Figures 3A to 3K Shown are top and end views of the second inner arm of a high-density electrode mapping catheter and related processing steps according to various embodiments of the present disclosure.

[0019] Figure 4A A top view of a machined inner lower structure is shown according to various embodiments of the present disclosure.

[0020] Figure 4B The various embodiments of the present disclosure are shown in Figure 4A An enlarged portion of the first inboard arm (indicated by dashed oval 4B) of the machined inboard substructure is shown in FIG.

[0021] Figure 4C The first outer side arm according to various embodiments of the present disclosure is shown along Figure 4B Cross-section of the midline cc.

[0022] Figure 4D The first outer side arm according to various embodiments of the present disclosure is shown along Figure 4B Cross-section of the midline cc.

[0023] Figure 5 Shown are cross-sectional views of patterned conductive traces formed on the top and bottom of a conductive flexible frame according to various embodiments of the present disclosure.

[0024] Figure 6A The conductive flexible frame is shown leaving exposed areas after an additional layer of dielectric material has been stripped from the distal portion of each conductive trace in accordance with various embodiments of the present disclosure.

[0025] Figure 6B The conductive flexible frame is shown after an additional layer of dielectric material has been stripped from a distal portion of each conductive trace, leaving exposed areas with solder deposited thereon, in accordance with various embodiments of the present disclosure.

[0026] Figure 6C The various embodiments of the present disclosure are shown in Figure 6B A cross-sectional end view of the machined conductive flexible frame along line ee is shown in FIG.

[0027] Figure 6D A hollow cylindrical hoop is shown according to various embodiments of the present disclosure.

[0028] Figure 6E A hollow cylindrical ferrule with solder deposited therein is shown according to various embodiments of the present disclosure.

[0029] Figure 6F The various embodiments of the present disclosure are shown in Figure 6D Isometric side and front views of a hollow cylindrical hoop shown in FIG.

[0030] Figure 6G A hollow cylindrical hoop is shown coaxially aligned with a machined conductive flexible frame in accordance with various embodiments of the present disclosure.

[0031] Figure 6H Processing steps for a hollow cylindrical hoop according to various embodiments of the present disclosure are shown.

[0032] Figure 6I Reference diagrams according to various embodiments of the present disclosure are shown. Figure 6H The hollow cylindrical hoop is bent after the processing step.

[0033] Figure 6J A bent hollow cylindrical ferrule and machined conductive flexible frame are shown after a solder reflow process according to various embodiments of the present disclosure.

[0034] Figures 7A-7C A top view and an end view of a second inner arm of a high-density electrode mapping catheter according to various embodiments of the present disclosure are shown, wherein a flexible frame of the high-density electrode mapping catheter is formed from a flexible substrate and related processing steps.

[0035] Figure 8A A top view of a machined inner lower structure is shown according to various embodiments of the present disclosure.

[0036] Figure 8B The various embodiments of the present disclosure are shown in Figure 8A An enlarged portion of the first inboard arm (indicated by the dashed oval 8B) of the machined inboard substructure is shown in FIG.

[0037] Figure 8C The various embodiments of the present disclosure are shown in Figure 8A An enlarged portion of the first inboard arm (indicated by dashed oval 8C) of the machined inboard substructure is shown in FIG.

[0038] Figure 9A A top view of a bottom mold for an overmolding process is shown according to various embodiments of the present disclosure.

[0039] Figure 9B The insertion of various embodiments according to the present disclosure is shown Figure 9AThe machined inner lower structure of the bottom mold is shown in FIG.

[0040] Figure 9C The assembly mold and the Figure 9B The inner lower structure of the processing along Figure 9B Cross-sectional side view along line hh.

[0041] Figure 9D A top view of a bottom mold and overmolded inner lower structure is shown after the overmolding process has been performed, according to various embodiments of the present disclosure.

[0042] Figure 9E The present invention shows various embodiments of the present invention. Figure 9D Assemble the mold and overmold the inner lower structure along Figure 9D Cross-section view of midline ii.

[0043] Figure 10A A cross-sectional side view of an ablation clamping device is shown with an overmolded inner understructure in place therein, according to various embodiments of the present disclosure.

[0044] Figure 10B shows the ablation process step after it has been completed according to various embodiments of the present disclosure. Figure 10A A top view of the ablation clamping device and the inner lower structure of the ablation overmold.

[0045] Figure 10C The various embodiments of the present disclosure are shown. Figure 10B FIG. 4 shows a top view of the inner lower structure of the ablation overmold after ejection of the ablation clamping device. FIG.

[0046] Figure 11 Mechanical properties of various materials that may be used to form the lower structure of a flexible head end portion according to various embodiments of the present disclosure are shown.

[0047] Figure 12A A top view of the proximal end of a medial understructure is shown, according to various embodiments of the present disclosure.

[0048] Figure 12B The present invention shows various embodiments of the present invention. Figure 12A 1 is a top view of an enlarged portion of a frame lock (represented by dashed circle 12B) on the proximal end of the inner lower structure shown in FIG.

[0049] Figure 12C The various embodiments of the present disclosure are shown in Figure 12B 1 is a top view of an enlarged portion of the electrical connection shown in FIG. 1 (represented by dashed circle 12C).

[0050] Figure 12D According to various embodiments of the present disclosure Figure 12C Cross-sectional view along line mm.

[0051] Figure 12E A top view of conductive lines electrically connected by electrical connections is shown according to various embodiments of the present disclosure.

[0052] Figure 13A A top view of a plurality of electrical connections on a first inner arm, a second inner arm, a first outer arm, and a second outer arm of a flexible frame of a flexible tip end portion of a high-density electrode mapping catheter according to various embodiments of the present disclosure is shown.

[0053] Figure 13B The present invention shows various embodiments of the present invention. Figure 13A A top view of a subset of the electrical connections on the first inner arm, second inner arm, first outer arm, and second outer arm of the flexible frame of the flexible tip end portion of the high-density electrode mapping catheter shown in FIG.

[0054] Figure 14 A method flow chart of a process for forming an integrated electrode structure including a conductive lower structure according to various embodiments of the present disclosure is shown.

[0055] Figure 15 A method flow chart of a process for forming an integrated electrode structure including a substrate lower structure according to various embodiments of the present disclosure is shown.

[0056] Figure 16 Shown is a side view of an arm of a high-density electrode mapping catheter according to various embodiments of the present disclosure.

[0057] Figures 17A to 17F Shown are side views of an arm of a high-density electrode mapping catheter and associated processing steps according to various embodiments of the present disclosure.

[0058] Figures 18A to 18G The present invention shows various embodiments of the present invention. Figure 1A A top view of an embodiment of the lower structure of a high-density electrode mapping catheter.

[0059] Figure 19A A top view of a flexible tip portion of a high-density electrode mapping catheter including a plurality of electrodes according to various embodiments of the present disclosure is shown.

[0060] Figure 19B The present invention shows a plurality of embodiments of the present invention. Figure 19A An enlarged top view of a pair of contact pads on the end of the flexible head is shown in FIG.

[0061] Figure 19C The present invention shows a plurality of embodiments of the present invention. Figure 19A An enlarged top view of the microelectrode on the end of the flexible tip is shown in FIG.

[0062] Figure 19D The present invention shows a plurality of embodiments of the present invention. Figure 19A Schematic side view of the top and bottom microelectrodes of the flexible tip are shown.

[0063] Figure 20 The various embodiments of the present disclosure are shown in Figure 19A Isometric side, top, and distal end views of the flexible tip end shown in .

[0064] Figure 21 A top view of the lower structure of the flexible tip portion of a high-density electrode mapping catheter according to various embodiments of the present disclosure is shown.

[0065] Figure 22 A top view of an alternative embodiment of the lower structure of a high-density electrode mapping catheter according to various embodiments of the present disclosure is shown.

[0066] Figures 23A to 23F Isometric top and side views of arms of the lower structure of a high-density electrode mapping catheter are shown in accordance with various embodiments of the present disclosure.

[0067] Figure 24A A top view of the lower structure of a flexible tip portion 660 of a high-density electrode mapping catheter including a plurality of electrodes, traces, and one contact pad is shown in accordance with various embodiments of the present disclosure.

[0068] Figure 24B The various embodiments of the present disclosure are shown in Figure 24A An enlarged top view of a portion of the second outer arm of the flexible head end portion is shown in FIG.

[0069] Figure 24C The various embodiments of the present disclosure include Figure 24A An enlarged top view of a portion of the flexible head end portion showing the contact pads.

[0070] Figure 25A A top view of the lower structure of a flexible tip portion of a high-density electrode mapping catheter including a plurality of electrodes and rows of contact pads according to various embodiments of the present disclosure is shown.

[0071] Figure 25B The various embodiments of the present disclosure are shown in Figure 25A An enlarged view of the flexible head end is shown in FIG.

[0072] Figure 25CThe various embodiments of the present disclosure are shown in Figure 25A An enlarged top view of the mounting portion of the flexible head end is shown in FIG.

[0073] Figure 26 shows a similar embodiment according to various embodiments of the present disclosure Figure 19A FIG. 5 shows a flexible tip portion of a high-density electrode mapping catheter including multiple wires connected to contact pads on a mounting portion.

[0074] Figure 27A Flexible cable sections according to various embodiments of the present disclosure are shown.

[0075] Figure 27B The various embodiments of the present disclosure are shown in Figure 27A A cross-sectional end view of the ground trace of the flexible cable is shown in FIG.

[0076] Figure 28 A flexible tip portion of a high-density electrode mapping catheter is shown located at the distal end of the catheter shaft according to various embodiments of the present disclosure.

[0077] Figure 29 A high-density electrode mapping catheter according to various embodiments of the present disclosure is shown.

[0078] Figure 30 Another embodiment of a high-density electrode mapping catheter in accordance with various embodiments of the present disclosure is shown.

[0079] Figure 31 Schematic diagrams and block diagrams of electromagnetic navigation systems according to various embodiments of the present disclosure are shown.

[0080] Figure 32 A control block flow diagram of a method for determining a degree of contact between a first electrode and tissue according to various embodiments of the present disclosure is shown.

[0081] Figure 33 A control block flow diagram of a method for determining cardiac activation associated with endocardial tissue according to various embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0082] The contents of International Application No. PCT / US2014 / 011940, entitled “Flexible High-Density Mapping Catheter Tips and Flexible Ablation Catheter Tips with Onboard High-Density Mapping Electrodes,” are incorporated herein by reference.

[0083] According to various embodiments of the present invention, Figure 1A The top view of the high-density electrode mapping catheter 101 is shown. Figure 1B Isometric side and top views of a high-density electrode mapping catheter 101 are shown. In some embodiments, the high-density electrode mapping catheter 101 may include a flexible tip portion 110 that forms a flexible array of microelectrodes 102. This planar array of microelectrodes 102 (or "paddle-like configuration") includes four side-by-side longitudinally extending arms 103, 104, 105, 106 that form a flexible frame on which the microelectrodes 102 are arranged. The four microelectrode-carrying arms include a first lateral arm 103, a second lateral arm 106, a first medial arm 104, and a second medial arm 105. These arms can be laterally separated from each other.

[0084] Each of the four arms may carry a plurality of microelectrodes 102. For example, each of the four arms may carry microelectrodes 102 spaced apart along the length of each of the four arms. Figure 1A and Figure 1B The high-density electrode mapping catheter 101 shown in the figure shows four arms, but the high-density electrode mapping catheter 101 can include more or fewer arms. Figure 1A and 1B The illustrated high-density electrode mapping catheter 101 shows 18 electrodes (e.g., 5 electrodes on the first lateral arm 103, 5 microelectrodes on the second lateral arm 106, and 4 microelectrodes on the first medial arm 104 and 4 microelectrodes on the second medial arm 105), but the catheter may include more or fewer than 18 microelectrodes. Additionally, the first lateral arm 103 and the second lateral arm 106 may include more or fewer than 5 microelectrodes, and the first medial arm 104 and the second medial arm 105 may include more or fewer than 4 microelectrodes.

[0085] In some embodiments, the microelectrode 102 can be used for diagnostic, therapeutic, and / or mapping procedures. For example, and without limitation, the microelectrode 102 can be used for electrophysiological studies, pacing, cardiac mapping, and ablation. In some embodiments, the microelectrode 102 can be used to perform unipolar or bipolar ablations. Such unipolar or bipolar ablations can create specific lines of lesions or patterns of lesions. In some embodiments, the microelectrode 102 can receive electrical signals from the heart, which can be used for electrophysiological studies. In some embodiments, the microelectrode 102 can perform position or location sensing functions associated with cardiac mapping.

[0086] In some embodiments, the high-density electrode mapping catheter 101 may include a catheter shaft 107. The catheter shaft 107 may include a proximal end and a distal end. The distal end may include a connector 108 that can connect the distal end of the catheter shaft 107 to the proximal end of the planar array. Figure 1A As shown, the catheter shaft 107 can define a catheter shaft longitudinal axis aa, and the first outer arm 103, the first inner arm 104, the second inner arm 105, and the second outer arm 106 can extend generally parallel to the longitudinal axis aa. The catheter shaft 107 can be made of a flexible material so that it can be passed through the tortuous vasculature of a patient. In some embodiments, the catheter shaft 107 can include one or more ring electrodes 111 arranged along the length of the catheter shaft 107. In examples, the ring electrodes 111 can be used for diagnostic, therapeutic, and / or mapping procedures.

[0087] like Figure 1B As shown, the flexible tip 110 can be adapted to conform to tissue (e.g., cardiac tissue). For example, when the flexible tip 110 contacts the tissue, the flexible tip 110 deflects to allow the flexible frame to conform to the tissue. In some embodiments, the arm (or the lower structure of the arm) includes a Figure 1A and 1B The paddle structure (or multiple arms, electrode bearing, flexible frame) at the distal end of the catheter shown, the arms may preferably be constructed of a flexible or spring-like material such as Nitinol and / or a flexible substrate as discussed herein. The structure of the arms (including, for example, the length and / or diameter of the arms) and the materials may be adjusted or customized to produce, for example, desired elasticity, flexibility, foldability, conformability, and stiffness properties, including one or more properties that may vary from the proximal end of a single arm to the distal end of the arm or between or among multiple arms comprising a single paddle structure. The foldability of materials such as Nitinol and / or a flexible substrate provides the additional advantage of facilitating insertion of the paddle structure into a delivery catheter or introducer, both during delivery of the catheter into the body and during removal of the catheter from the body at the conclusion of the procedure.

[0088] Disclosed herein are catheters having multiple microelectrodes that can be used to: (1) define regional conduction maps of specific sized areas (e.g., one square centimeter area) within the atrial wall of the heart; (2) identify complex, fragmented atrial electrograms for ablation; (3) identify local focal potentials between microelectrodes to obtain higher electrogram resolution; and / or (4) more precisely target ablation areas. These mapping catheters and ablation catheters are constructed to conform to and maintain contact with cardiac tissue despite potential irregular cardiac motion. This enhanced stability of the catheter on the cardiac wall provides more accurate mapping and ablation during cardiac motion due to continued tissue-electrode contact. Additionally, the catheters described herein can be used for both endocardial and epicardial applications. For example, the planar array embodiments shown herein can be used in endocardial surgery, in which the planar array of microelectrodes is located between the myocardial surface and the pericardium. Alternatively, the planar array embodiments can be used in epicardial surgery to rapidly scan and / or analyze the inner surface of the myocardium and rapidly generate high-density maps of the electrical properties of cardiac tissue.

[0089] Figure 2A According to various embodiments of the present invention Figure 1A Isometric side and top views of the inner lower structure 120 (also referred to herein as the inner lower structure) of the high-density electrode mapping catheter are shown. In some embodiments, the inner lower structure 120 can be formed from a flexible material or spring-like material as described herein, such as a nitinol alloy and / or a flexible substrate. The inner lower structure 120 can include a first inner arm lower structure 121 and a second inner arm lower structure 122. Although not shown, the outer lower structure (also referred to herein as the outer lower structure) that provides the lower structure for the first outer arm 103 and the second outer arm 106 can be formed and / or processed in a manner similar to that discussed with reference to the inner lower structure 120. In addition, if the high-density electrode mapping catheter includes additional arms, those arms can be formed and / or processed in a manner similar to that described with reference to the inner lower structure 120. For simplicity, the discussion will be directed to the inner lower structure 120. As shown, the inner lower structure 120 can include a first inner mounting arm 123 and a second inner mounting arm 124. The inner mounting arm can be inserted into the distal end of the catheter 107 and through the connector 108 and can be used to connect the flexible tip 110 to the distal end of the catheter 107. In some embodiments, the inner mounting arm can be inserted through a torsion pad as discussed herein.

[0090] like Figure 2AAs shown, the inner lower structure 120 (although the outer lower structure is not shown) can be formed from a planar piece of material. However, in some embodiments, the inner lower structure 120 (and the outer lower structure) can be formed from a cylindrical, square, or other lower structure shape. In some embodiments, the inner lower structure 120 and the outer lower structure can be formed as shown in FIG. Figures 18A to 18G The is formed from a single monolithic piece of material.

[0091] Figure 2B Isometric side and top views of the coated inner substructure 122-1 of the high-density electrode mapping catheter 101 according to various embodiments of the present disclosure are shown. In some prior practices, the high-density electrode mapping catheter can be assembled using tubular subassemblies for the inner substructure and the outer substructure. One reason for using a tube when assembling the substructure is to allow wires to be passed through the tube to connect each individual microelectrode. Because each wire can be individually passed through the tube and connected to each microelectrode individually, this process is labor and / or cost intensive. Further, it is challenging to ensure that a reliable electrical connection is established between each microelectrode and its wire.

[0092] Additionally, because the tube walls can be symmetrical and not biased to bend in a particular manner, the use of a tube can result in less predictable deflection of the flexible tip. Embodiments of the present disclosure can provide more predictable deflection of the flexible tip 110. Embodiments of the present disclosure can provide a less labor- and cost-intensive assembly process and more predictable deflection of the flexible tip 110. In some embodiments, a plurality of patterned conductive traces can be located on the flexible frame of an expandable structure. For example, a plurality of patterned conductive traces can be located on the flexible frame of an expandable medical device structure. Some embodiments of the present disclosure can provide the flexible tip 110 with a plurality of patterned conductive traces located on the flexible frame of the flexible tip 110, as discussed herein, instead of individually extending conductive wires. The patterned conductive traces can be electrically connected to the plurality of microelectrodes 102 located on the flexible tip 110. The patterned conductive traces can be formed using a process that is less labor- and / or cost-intensive than current practices. Some embodiments of the present disclosure can provide a means for detecting electrical connectivity between the microelectrodes 102 and the patterned conductive traces and / or conductive wires that electrically connect the plurality of microelectrodes 102.

[0093] In some embodiments of the present disclosure, the inner lower structure may be coated with a dielectric material. In some embodiments, an example of a dielectric material may include parylene. Other dielectric materials, such as polyimide (e.g., PI-2771 or HD-4004 available from HD Microsystems) and / or epoxy (SU8 epoxy available from Microchem), may be used depending on the design and end-use requirements. In some embodiments where the lower structure is a conductive material, the dielectric may electrically insulate the conductive traces from the conductive material as described herein.

[0094] Figures 3A to 3K Shows a top view and an end view of the second inner arm of the high-density electrode mapping catheter according to various embodiments of the present disclosure and related processing steps (in Figures 3A to 3K A top view is shown above the end view). Figure 3A The conductive flexible frame 130 of the inner lower structure 120 is shown coated with a dielectric material 131 according to various embodiments of the present disclosure. In an example, a dielectric material can be applied to the conductive flexible frame 130 so that the conductive flexible frame 130 is coated with the dielectric material 131 to provide an electrically insulating layer on which patterned conductive traces can be located.

[0095] Figure 3B A conductive flexible frame 130 (also referred to as a flexible frame) is shown with an inner lower structure 120 coated with a dielectric material 131 and a mask 134 (also referred to as a mask portion) according to various embodiments of the present disclosure. In an example, one or more unmasked trace pattern portions 132-1, 132-2, 132-3 can be formed on the dielectric coating of the conductive flexible frame 130 by the mask 134. In some embodiments, the mask 134 can form a channel 136 along the dielectric material, in which a conductive material can be deposited to form a conductive trace.

[0096] Figure 3C The deposition of various embodiments of the present disclosure is shown in FIG. Figure 3BThe seed layers 138-1, 138-2, 138-3 are deposited in the unmasked trace pattern portions 132-1, 132-2, 132-3. In some embodiments, the seed layer can be deposited within the channel 136 so that the seed layer 138-1, 138-2, 138-3 partially fills the channel. In some embodiments, the seed layer 138-1, 138-2, 138-3 can include copper (Cu), nickel (Ni), aluminum (Al), etc. The seed layers 138-1, 138-2, 138-3 can provide a base layer on which the conductive material layer is deposited. In an example, the seed layers 138-1, 138-2, 138-3 can provide an interface between the dielectric material 131 and the conductive material, which is deposited on the conductive flexible frame 130 to form the conductive traces. For example, the seed layer may allow the conductive material to adhere to the dielectric material 131 (eg, the conductive material adheres to the dielectric material 131 through the seed layers 138 - 1 , 138 - 2 , 138 - 3 ).

[0097] Figure 3D The seed layers 138-1, 138-2, 138-3 are shown plated with a conductive material (e.g., copper) to form conductive traces 140-1, 140-2, 140-3 according to various embodiments of the present disclosure. In this example, the conductive material is deposited on the seed layers 138-1, 138-2, 138-3 and is therefore bonded to the dielectric material 131. However, because portions surrounding the conductive traces 140-1, 140-2, 140-3 are masked, the conductive material is not deposited at these locations.

[0098] Figure 3E A conductive flexible frame 130 coated with a dielectric material 131 and conductive traces 140-1, 140-2, and 140-3 are shown according to various embodiments of the present disclosure. In some embodiments, the mask portion 134 can be peeled off, leaving the conductive traces 140-1, 140-2, and 140-3 exposed on the dielectric material 131 coated on the conductive flexible frame 130. In examples, the dielectric material 131 can insulate the conductive traces 140-1, 140-2, and 140-3 from the conductive flexible frame 130, thereby preventing short circuits between the conductive traces 140-1, 140-2, and 140-3.

[0099] Figure 3FThe conductive flexible frame 130 is shown coated with an additional dielectric material layer 141 according to various embodiments of the present disclosure. The additional dielectric material layer 141 can be deposited over the initial dielectric material layer 131 and over the conductive traces 140-1, 140-2, 140-3. In some embodiments, the additional dielectric material layer 141 can be deposited only on one side of the conductive flexible frame 130 where the conductive traces 140-1, 140-2, 140-3 are located.

[0100] Figure 3G The conductive flexible frame 130 is shown after the additional dielectric material layer 141 has been stripped from the distal portion of each conductive trace 140-1, 140-2, 140-3, leaving exposed regions 142-1, 142-2, 142-3. In some embodiments, laser ablation can be used to strip the distal portion of each conductive trace 140-1, 140-2, 140-3 to create the exposed regions 142-1, 142-2, 142-3. In some embodiments, the additional dielectric material layer can be removed by laser ablation. In some embodiments, the exposed regions 142-1, 142-2, 142-3 can be formed using a photodefinable dielectric material, wherein the exposed regions 142-1, 142-2, 142-3 are masked, with the dielectric material patterned in the masked regions. The photodefinable dielectric material may be developed and the masking material may be stripped to form exposed areas 142 - 1 , 142 - 2 , 142 - 3 .

[0101] Figure 3H The mask-defining regions 143-1, 143-2, 143-3 on the conductive flexible frame 130 according to various embodiments of the present disclosure are shown. In some embodiments, the mask material (e.g., mask portions 144-1, 144-2, 144-3) can be a photodefinable material, wherein the mask material can be patterned on the mask portions 144-1, 144-2, 144-3 and developed to form the mask portions 144-1, 144-2, 144-3. The mask portions can be located proximal and distal to the distal portion of each conductive trace 140-1, 140-2, 140-3 (and exposed areas 142-1, 142-2, 142-3) to form the mask-defining regions 143-1, 143-2, 143-3.

[0102] Figure 3ISeed layers 145-1, 145-2, 145-3 are shown deposited on mask-defined regions 143-1, 143-2, 143-3, according to various embodiments of the present invention. As described above, the seed layers 145-1, 145-2, 145-3 can be deposited within the mask-defined regions. In some embodiments, the seed layers 145-1, 145-2, 145-3 can include copper (Cu), nickel (Ni), aluminum (Al), or the like. The seed layers 145-1, 145-2, 145-3 can provide a base layer upon which a layer of conductive material can be deposited. In an example, the seed layers 145-1, 145-2, 145-3 can provide an interface between the additional dielectric material layer 141 and the distal portions of the conductive traces 140-1, 140-2, 140-3, and subsequently, the conductive material that forms the microelectrode 102 is applied. For example, the seed layer may allow the conductive material forming the microelectrodes to adhere to the additional dielectric material 141 and the distal portions of the conductive traces 140 - 1 , 140 - 2 , 140 - 3 .

[0103] Figure 3JMicroelectrodes 146-1, 146-2, 146-3 are shown formed on a conductive flexible frame 130 by an electroplating process according to various embodiments of the present disclosure. In some embodiments, the seed layers 145-1, 145-2, 145-3 may be electroplated with a conductive material to form the microelectrodes 146-1, 146-2, 146-3. In some embodiments, the conductive material used to form the microelectrodes 146-1, 146-2, 146-3 may include a platinum-iridium alloy (Pt-Tr). The platinum-iridium alloy coating process can be carried out as described in the following documents: Rao, Chepuri RK and Trivedi, DC, Chemical and electrochemical deposition of platinum group metals and their applications, Coordination Chemistry Reviews, 249, (2005) pp. 613-631; Sheela G. et al., Iridium electrodeposition, Electrochemical Bulletin, 15(5-6) May-June 1999, pp. 208-210; Wu, Feng et al., Electrodeposition of platinum-based iridium alloys on nickel-based single crystal superalloy TMS75, Surface and Coating Technology, Vol. 184, No. 1, June 1, 2004; Baumgartner, ME and Raub, Ch.J., Electrodeposition of platinum and platinum alloys, Platinum Metal Reviews, 1988, 32, (4), 188-197; Ohno, Izumi, Chemical deposition of palladium and platinum, Modern Electroplating, 5th edition, by Mordechay Schlesinger and Milan Paunovic, ed., Copyright 2010, John Wiley & Sons, Inc. Chapter 20, 477-482; Electroplating of Platinum Group Metals - A Recent Survey of Processing and Applications, Platinum Metal Reviews, 1970, 14(3) pp. 93-94; and / or Yingna Wu et al., Characterization of Platinum-Iridium Alloys Electroplated on Nickel-Based Single Crystal Superalloys, Acta Materialia, Vol. 46, No. 10 (2005) pp. 2176-2179, which are incorporated herein by reference.

[0104] In some embodiments, the conductive material can be plated circumferentially around the flexible frame 130. For example, the conductive material can extend circumferentially around one of the first and second medial arm lower structures 121, 122. Thus, the seed layers 145-1, 145-2, 145-3 and the mask portions 144-1, 144-2, 144-3 can extend circumferentially around the first and second medial arm lower structures 121, 122, such that the conductive material can be plated circumferentially around the flexible frame 130. Thus, the microelectrodes 146-1, 146-2, 146-3 can be formed as ring electrodes that are coaxial with a corresponding one of the first and second medial arm lower structures 121, 122.

[0105] Figure 3KA conductive flexible frame 130 coated with dielectric 131 is shown, including an additional dielectric material layer 141, conductive traces 140-1, 140-2, 140-3, and microelectrodes 146-1, 146-2, 146-3. In some embodiments, mask portions 144-1, 144-2, 144-3 can be peeled away, thereby exposing the dielectric-coated conductive traces 140-1, 140-2, 140-3 on the conductive flexible frame 130 coated with dielectric 131. The microelectrodes 146-1, 146-2, 146-3 can be electrically connected to each corresponding conductive trace 140-1, 140-2, 140-3, while remaining insulated from each other due to the additional dielectric material 141 coating the conductive traces 140-1, 140-2, 140-3.

[0106] Figure 4A A top view of a processed inner lower structure 160 is shown, according to various embodiments of the present disclosure. Figure 4B The various embodiments of the present disclosure are shown in Figure 4A 4B). FIG. 4B shows an enlarged portion of a first inner arm 164 (represented by a dashed oval 4B) of a processed inner lower structure. As shown, the processed inner lower structure 160 may have a dielectric coating 161 that coats the conductive flexible frame (e.g., conductive flexible frame 130) of the processed inner lower structure 160. The dielectric coating 161 may be located between each of a plurality of patterned conductive traces 162-1, 162-2, 162-3 and the conductive flexible frame. The dielectric coating 161 may insulate the patterned conductive traces 162-1, 162-2, 162-3 from the conductive flexible frame, thereby preventing short circuits between the patterned conductive traces 162-1, 162-2, 162-3. In some embodiments, the first patterned conductive trace 162-1 can be electrically connected to the first microelectrode 163-1; the second patterned conductive trace 162-2 can be electrically connected to the second microelectrode 163-2; and the third patterned conductive trace 162-3 can be electrically connected to the third microelectrode 163-3.

[0107] In some embodiments, the plurality of microelectrodes 163-1, 163-2, 163-3 may be arranged in groups. For example, although more or less than three microelectrodes 163-1, 163-2, 163-3 may be arranged in groups along the first inner arm 164, Figure 4A The plurality of microelectrodes 163-1, 163-2, 163-3 shown positioned along the first inner arm 164 may be arranged in corresponding groups of three microelectrodes. Figure 1AAs shown, the microelectrode groups can be arranged along the second inner arm 165, along the first outer arm, and / or along the second outer arm. In some embodiments, the high-density electrode mapping catheter 101 can include more or fewer than four arms.

[0108] The plurality of microelectrode groups may be arranged in corresponding rows of longitudinally aligned microelectrodes aligned parallel to the longitudinal axis a'a' of the catheter shaft. Figure 1A As shown, the plurality of patterned conductive traces 162-1, 162-2, 162-3 can be aligned parallel to the catheter shaft longitudinal axis a'a'.

[0109] Figure 4C The first outer side arm 164 is shown along the Figure 4B Cross-sectional view of the midline cc. Figure 4D The first outer side arm 164 is shown along the Figure 4B Cross-sectional view along the midline dd. As shown, the first outer arm 164 includes a conductive flexible frame 165 that has been coated with a dielectric material 166', 166". In some embodiments, the conductive flexible frame 165 may be coated with an upper layer of dielectric material 166' and a lower layer of dielectric material 166". However, the conductive flexible frame 165 may be circumferentially coated with a dielectric material as described herein such that microelectrodes circumferentially and coaxially disposed around the conductive flexible frame 165 are insulated from the conductive flexible frame 165, preventing short circuits between the plurality of microelectrodes located on the conductive flexible frame 165.

[0110] As described herein, the first patterned conductive trace 162-1 can be located on top of the upper dielectric material 166' and electrically connected to the first microelectrode 163-1' through an exposed area located at a distal portion of the first patterned conductive trace 162-1. Figures 3H to 3K As described above, the first microelectrode 163-1' can be coupled to the first patterned conductive trace 162-1 by electroplating a mask-defined area (e.g., mask-defined area 145-3). The first microelectrode 163-1' can contact an exposed area 168 (e.g., exposed area 142-3) of the first patterned conductive trace 162-1, thereby electrically connecting the first patterned conductive trace 162-1 and the first microelectrode 163-1'. In some embodiments, the first microelectrode 163-1' can be electrically connected to the exposed area 168 of the first patterned conductive trace 162-1 proximal to the distal end 167 of the first patterned conductive trace 162-1.

[0111] like Figure 4CAs shown, the second patterned conductive trace 162-2 (and the third patterned conductive trace 162-3 obscured by the second patterned conductive trace 162-2) can extend distally relative to the first microelectrode 163-1' and can be electrically connected to the second microelectrode 163-2 (and the third microelectrode 163-3). As described herein, the second patterned conductive trace 162-2 (and the third patterned conductive trace 162-3) can be electrically insulated from the first microelectrode 163-1' by an additional layer 169 of dielectric material.

[0112] In some embodiments, a single layer or multiple layers of patterned conductive traces may be formed on the conductive flexible frame 165. For example, the processed inner lower structure 160 is shown as including a single layer of patterned conductive traces 162-1, 162-2, 162-3. However, in some embodiments, the processed inner lower structure 160 may include multiple layers of patterned conductive traces. This is desirable when an increased number of microelectrodes are placed on one or more inner and / or outer arms, the width of the frame is reduced, thereby reducing the placement area of ​​the patterned conductive traces; and / or the width of the patterned conductive traces is increased (e.g., due to the material selection for the traces). For example, as the number of microelectrodes increases, the width of the arm may not be sufficient to completely separate the patterned conductive traces from each other to prevent crosstalk and / or short circuits between the patterned conductive traces. In this manner, multiple layers of patterned conductive traces may be formed on the arms, with each layer separated from each other by a dielectric material.

[0113] In some embodiments, for example, referring to Figure 16 As described above, the connection between each patterned conductive trace and the associated microelectrode can be achieved by filling the via. In some embodiments of the present disclosure, five patterned conductive traces and associated microelectrodes can be formed within a single layer of patterned conductive traces, depending on the width of each corresponding arm, and formed along a single arm using a 0.001 inch line (e.g., conductive trace) and space (e.g., spacing between conductive traces) substrate design. For example, each patterned conductive trace can be 0.001 inches wide, with each patterned conductive trace spaced 0.001 inches from the adjacent patterned conductive trace. In some embodiments, as Figure 5 As shown, where a greater number of microelectrodes and / or patterned conductive traces are desired, multiple layers of patterned conductive traces may be employed and / or additional traces may be formed on opposite sides of the conductive flexible frame.

[0114] Figure 51 and 1 , and a cross-sectional view of patterned conductive traces formed on the top and bottom of the conductive flexible frame according to various embodiments of the present disclosure is shown. In some embodiments, the conductive flexible frame 180 may be coated with a dielectric material as described herein. The dielectric material may be located between the patterned conductive traces 181-1, 181-2, 181-3, 181-4 and the conductive flexible frame 180, which may be used to insulate the patterned conductive traces 181-1, 181-2, 181-3, 181-4 from the conductive flexible frame 180. In some embodiments, the conductive flexible frame 180 may be coated with a dielectric material as described herein. Figures 3A to 3K In the manner described above, one or more patterned conductive traces (e.g., patterned conductive traces 181-1 and 181-2) can be formed on the top of the conductive flexible frame 180, and one or more patterned conductive traces (e.g., patterned conductive traces 181-3 and 181-4) can be formed on the bottom of the conductive flexible frame 180. Accordingly, four microelectrodes can be placed along the conductive flexible frame 180. For example, in some embodiments, the first microelectrode 182 can be placed proximal to the second microelectrode 183.

[0115] Figure 6A The conductive flexible frame 130' is shown after the additional dielectric material layer 141' has been peeled away from the distal portion of each conductive trace 140-1', 140-2', 140-3', leaving exposed areas 142-1', 142-2', 142-3' according to various embodiments of the present disclosure. Figure 3A To 3G related processing steps to obtain Figure 6A In some embodiments, solder may be deposited on the distal portion of each conductive trace (e.g., traces 140-1', 140-2', 140-3') rather than plating the exposed areas 142-1', 142-2', 142-3'. For example, Figure 6B The processed conductive flexible frame 199 is shown after the additional dielectric material layer 140-1' has been stripped from the distal portion of each conductive trace 140-1', 140-2', 140-3', leaving exposed areas 142-1', 142-2', 142-3' with solder 191-1, 191-2, 191-3 deposited thereon, in accordance with various embodiments of the present disclosure. Figure 6C Shown in Figure 6B A cross-sectional end view of the machined conductive flexible frame 199 along line ee is shown in FIG.

[0116] Figure 6D A hollow cylindrical hoop 200 is shown in accordance with various embodiments of the present disclosure. Figure 6EFIG. 6F shows a hollow cylindrical hoop 203 with solder 208 deposited therein according to various embodiments of the present disclosure. Figure 6D In some embodiments, the hollow cylindrical hoop 200 may be identical or similar to the one shown in FIG. Figure 6E In some embodiments, the hollow cylindrical hoop 200 may include a cutout 201 that may extend longitudinally downward from the sidewall of the hollow cylindrical hoop. Figure 6D (and 6F) show that the cutout 201 extends parallel to the longitudinal axis of the hollow cylindrical ferrule 200, but the cutout 201 can be offset from the longitudinal axis of the hollow cylindrical ferrule 200.

[0117] In some embodiments, as Figure 6G As shown, the hollow cylindrical hoop 200 can be coaxially aligned with the processed conductive flexible frame 199. In some embodiments, the hollow cylindrical hoop 200 can be slid from over the proximal ends of the arms of the processed conductive flexible frame 199 to a position over the solder 191-1. For example, the hollow cylindrical hoop 200 can be placed over the solder 191-1 so that the solder 191-1 is aligned with the hollow cylindrical hoop 200 between the proximal and distal ends of the hollow cylindrical hoop 200. In some embodiments, the circumferential width of the cutout 201 in the hollow cylindrical hoop 200 (in Figure 6D The height of the processed conductive flexible frame (defined by line gg in Figure 6C ff) so that the hollow cylindrical hoop 200 (e.g., the cutout 201 of the hollow cylindrical hoop 200) can be slid laterally over the processed conductive flexible frame 199, rather than sliding over the proximal ends of the arms of the processed conductive flexible frame 199.

[0118] Figure 6H 1 , processing steps for a hollow cylindrical ferrule 200 according to various embodiments of the present disclosure are shown. In some embodiments, the hollow cylindrical ferrule 200 can be coaxially aligned with the processed conductive flexible frame 199, as described herein, and the solder 191-1 can be aligned with the hollow cylindrical ferrule 200 between the proximal and distal ends of the hollow cylindrical ferrule 200. The hollow cylindrical ferrule 200 can be bent onto the processed conductive flexible frame 199. In an example, a force can be applied to the hollow cylindrical ferrule 200 in the direction of at least one arrow (e.g., arrow 205) to bend the hollow cylindrical ferrule 200 onto the processed conductive flexible frame 199. Figure 6I The various embodiments of the present disclosure are shown in FIG. Figure 6HThe bent hollow cylindrical hoop 206 is shown after a processing step. As shown, the circumferential width of the cutout 202 is reduced due to the bending process and the bent hollow cylindrical hoop 206 may contact portions of the processed conductive flexible frame 199 (e.g., the processed corners of the conductive flexible frame 199 and the solder 191-1).

[0119] Figure 6J FIG. 2 shows a hollow cylindrical hoop 206 and a processed conductive flexible frame 199 bent after a reflow soldering process according to various embodiments of the present disclosure. In an example, a reflow process may be performed to Figure 6I , the solder reflows as shown in FIG, such that the reflowed solder 207 distributes and contacts the bent hollow cylindrical ferrule 206 and the processed conductive flexible frame 199. The solder 207 can contact the bent hollow cylindrical ferrule 206 and the processed conductive flexible frame 199 and can electrically connect the conductive trace 140-1 and the bent hollow cylindrical ferrule 206. As such, the bent hollow cylindrical ferrule 206 forms a microelectrode as described herein.

[0120] refer to Figure 6E , where solder 208 is deposited on the hollow cylindrical hoop 203, the solder (e.g., solder 191-1) may or may not be placed on the exposed areas 142-1', 142-2', 142-3' of the conductive traces 140-1', 140-2', 140-3'. In an example, the hollow cylindrical hoop 203 may be placed over the processed conductive flexible frame 199 so that the solder 208 is close to the exposed areas 142-1', 142-2', 142-3' of the conductive traces 140-1', 140-2', 140-3'. In some embodiments, reference may be made to Figures 6G-6J The processing steps shown and described are to bend the hollow cylindrical ferrule 203 and reflow the solder 208 to establish a connection between the hollow cylindrical ferrule 203 and the processed conductive flexible frame 199 and to establish an electrical connection between the hollow cylindrical ferrule 203 and the conductive trace 140-1'. In some embodiments, solder may be deposited on the exposed areas 142-1', 142-2' of the hollow cylindrical ferrule 203 and the conductive traces 140-1', 140-2', 140-3' to allow for improved solder distribution during reflow soldering.

[0121] Figure 7A 1 shows a top view and an end view of the second inner arm of the high-density electrode mapping catheter according to various embodiments of the present disclosure, wherein the flexible frame 220 of the high-density electrode mapping catheter is formed by a flexible substrate and related processing steps (in Figures 7A to 7CIn some embodiments, the flexible frame 220 may be formed from a flexible substrate. In some embodiments, the flexible substrate may include, for example, a reference Figure 11 For example, the printed circuit board may be formed from fiberglass and / or plastic that is not conductive. In some embodiments, the printed circuit board may be formed from a polymer. Figure 7A As shown, in some embodiments, a flexible substrate 220 may be coated with a conductive material 222. The conductive material 222 may, for example, comprise Cu (although other conductive materials may be used).

[0122] Figure 7B A top view and an end view of the second inner arm of a high-density electrode mapping catheter according to various embodiments of the present disclosure are shown, wherein a masking layer is deposited on the conductive material 222 coating the flexible frame 220 to form mask trace patterns 223-1, 223-2, 223-3 and unmasked portions on the coated flexible frame. In the example, the surrounding areas of the mask trace patterns 223-1, 223-2, 223-3 include uncoated conductive material 222.

[0123] Figure 7C 1 shows a top view and an end view of the second inner arm of the high-density electrode mapping catheter, wherein the surrounding areas of the mask trace patterns 223-1, 223-2, 223-3 have been stripped of the conductive material 222. In an example, the conductive material 222 can be stripped to expose the flexible substrate 220 surrounding the mask trace pattern 223-1. Figure 7C As shown, the mask trace patterns 223-1, 223-2, and 223-3 have been peeled off to expose the conductive traces 224-1, 224-2, and 224-3. The conductive traces 224-1, 224-2, and 224-3 can be directly connected to the electrically insulating flexible substrate 220. Accordingly, the conductive traces 224-1, 224-2, and 224-3 can be electrically isolated from each other, thereby preventing short circuits between the conductive traces 224-1, 224-2, and 224-3.

[0124] In some embodiments, as will be apparent to those skilled in the art, Figure 7C The embodiment shown in FIG. Figures 3E to 3K and / or Figures 6A to 6J For example, a dielectric coating may be deposited over the conductive traces 224-1, 224-2, 224-3 and the flexible substrate 220, and may form exposed areas of the conductive traces 224-1, 224-2, 224-3.

[0125] Figure 8AA top view of the machined inner lower structure 228 is shown in accordance with various embodiments of the present disclosure. Figure 8B The various embodiments of the present disclosure are shown in Figure 8A FIG2 is an enlarged view of a first inner arm 230 (indicated by dashed oval 8B) of a processed inner lower structure 228 shown in FIG2 . The processed inner lower structure 228 includes a first inner arm 230 and a second inner arm 231. In some embodiments, as described herein, the processed inner lower structure 228 can be formed from a flexible substrate. For example, in some embodiments, the flexible substrate includes a printed circuit board and / or a polymer. In some embodiments, the flexible substrate can be coated with a dielectric material 232.

[0126] The first inner arm 230 of the processed inner lower structure 228 includes conductive traces 224-1, 224-2, 224-3 and microelectrodes 227-1, 227-2, 227-3. The first conductive trace 224-1 can be electrically connected to the first microelectrode 227-1; the second conductive trace 224-2 can be electrically connected to the second microelectrode 227-2; and the third conductive trace 224-3 can be electrically connected to the third microelectrode 227-3. The second inner arm 231 of the processed inner lower structure 228 includes conductive traces 226-1, 226-2, 226-3 and microelectrodes 229-1, 229-2, 229-3. The first conductive trace 226 - 1 may be electrically connected to the first microelectrode 229 - 1 ; the second conductive trace 226 - 2 may be electrically connected to the second microelectrode 229 - 2 ; and the third conductive trace 226 - 3 may be electrically connected to the third microelectrode 229 - 3 .

[0127] Figure 8C The various embodiments of the present disclosure are shown in Figure 8A FIG. 8 is an enlarged portion of the first inner arm 230 (indicated by the dashed oval 8B) of the processed inner lower structure 228 shown in FIG. Figure 8C A first conductive trace 224-1 electrically connected to a first proximal terminal contact pad 235-1; a second conductive trace 224-2 electrically connected to a second proximal terminal contact pad 235-2; and a third conductive trace 224-3 electrically connected to a third proximal terminal contact pad 235-3 are shown. Figure 8A The proximal terminal contact pads are not shown. In some embodiments, the flexible frame of the flexible tip portion 110 of the high-density electrode mapping catheter 101 may include proximal terminal contact pads. For example, each arm of the medial lower structure and / or each arm of the lateral lower structure (and / or additional lower structures not shown) may include a proximal terminal contact pad along a proximal portion of the medial lower structure and / or the lateral lower structure.

[0128] In some embodiments, the proximal terminal contact pads 235-1, 235-2, 235-3 can provide electrical connection points for electrically connecting microelectrodes (e.g., microelectrodes 227-1, 227-2, 227-3). For example, the proximal terminal contact pads 235-1, 235-2, 235-3 can provide an increased area for electrical connection with each conductive trace 226-1, 226-2, 226-3, and therefore each microelectrode 227-1, 227-2, 227-3. In some embodiments, the proximal terminal contact pads 235-1, 235-2, 235-3 can be used to electrically detect continuity between each conductive trace and the corresponding electrode. For example, each proximal terminal contact pad can be probed using an electrical detection device to ensure that an uninterrupted electrical connection exists between each proximal terminal contact pad, a corresponding conductive trace, and the corresponding microelectrode. In some embodiments, the proximal terminal contact pads can provide an increased area for probing using an electrical detection device (e.g., as opposed to probing each individual conductive trace).

[0129] Figure 9A 1 shows a top view of a bottom mold 245 for an overmolding process according to various embodiments of the present disclosure. The bottom mold 245 includes a cavity 246 that can be sized and configured to accommodate a lower structure (e.g., a processed lower structure) of the flexible head end portion 110. In some embodiments, different molds can be used for the outer lower structure and the inner lower structure (and, if included, additional lower structures). In some embodiments, the bottom mold 245 can be sized and configured as follows: Figure 9B The processed inner lower structure 160 and / or the processed inner lower structure 228 are shown received in the cavity 246 .

[0130] Figure 9B FIG. 2 shows a top view of a processed inner lower structure 228 inserted into a bottom mold 245 according to various embodiments of the present disclosure. Figure 8A The processed inner lower structure 228 shown in FIG is shown inserted into the cavity 246 of the bottom mold 245 . Figure 9C The assembled mold 250 according to various embodiments of the present disclosure is shown along Figure 9B Cross-sectional side view along line hh.

[0131] Figure 9CThe top mold 247 and bottom mold 245 are shown in a closed position, thereby enclosing the processed inner lower structure 228 (composed of the distal portion 228-1 of the processed inner lower structure 228 and the proximal portion 228-2 of the processed inner lower structure 228) within the mold cavity and forming the assembled mold 250. In the example, the assembled mold 250 includes a bottom cavity 246. A cross-sectional view of the bottom cavity 246 shows the distal bottom cavity 246-1 and the proximal bottom cavity 246-2. The bottom cavity 246 can be formed in the bottom mold 245. In the example, the assembled mold 250 includes a top cavity 248. A cross-sectional view of the top cavity 248 shows the distal top cavity 248-1 and the proximal top cavity 248-2. The top cavity 248 can be formed in the top mold 247 of the assembled mold 250.

[0132] In some embodiments, bottom mold 245 and top mold 247 may include standoffs (not shown) that extend into bottom cavity 246 and top cavity 248 to position processed inner lower structure 228 a specific distance away from the walls of bottom mold 245 and top mold 247 that form bottom cavity 246 and top cavity 248. In examples, the distance between processed inner lower structure 228 and the walls of bottom mold 245 and top mold 247 may define the thickness of the overmold covering the lower structure.

[0133] In some embodiments, the top mold 247 and / or the bottom mold 245 may include ports 249 configured to introduce overmold material into the bottom cavity 246 and the top cavity 248. In some embodiments, the assembly mold 250 may include a gate and runner system to facilitate distributing the overmold material into the bottom cavity 246 and the top cavity 248. The gate and runner system may be designed based on the rheological properties of the overmold material.

[0134] Figure 9D A top view of the bottom mold 245 and the overmolded inner lower structure 260 is shown after the overmolding process has been performed, according to various embodiments of the present disclosure. Figure 9E The various embodiments of the present disclosure are shown in Figure 9D The middle assembly mold and overmolded lower structure along the inner Figure 9D2. Cross-sectional view of center line ii. As shown, the processed inner lower structure 228 is overmolded with an overmolding material 261. The overmolding material 261 is injected through port 249 and fills the space between the walls of the processed inner lower structure 228 and the bottom mold 245 and the top mold 247 (e.g., assembly mold 250). In some embodiments, the overmolding material 261 may include polyether block amide (e.g., nylon elastomer (PEBAX) available from Arkema). In some embodiments, the overmolding material may be polyurethane (e.g., Pellethane 2363-80A or 2363-90A available from Lubrizol Corp., or Tecoflex EG93A or EG100A) or other suitable materials having the biocompatibility, elasticity, and mechanical properties required for specific design and end-use requirements.

[0135] Figure 10A A cross-sectional side view of an ablation tool 270 is shown with an overmolded inner lower structure positioned therein, according to various embodiments of the present disclosure. As shown, microelectrodes 229-1, 229-2, and 229-3 have been overmolded with overmolding material 261. In some embodiments, the ablation tool 270 may include an ablation reference point 271, which, in some embodiments, can be referenced by an ablation tool. While the location of the ablation reference point 271 is shown as being proximal to the overmolded inner lower structure 260, the reference point 271 can be located distally relative to the overmolded inner lower structure 260 and / or on any side of the overmolded inner lower structure 260. The ablation tool, which can be a laser and / or other type of ablation tool, can, in some embodiments, reference the ablation point 271 so that overmolding material 261 covering (e.g., covering the surface of) the microelectrodes 229-1, 229-2, and 229-3 can be accurately removed by the ablation tool.

[0136] In some embodiments, as shown, reference point 271 may be located at a specific distance from each microelectrode represented by line jj, line kk, and line 11. In some embodiments, the ablation tool may ablate the overmold material 261 proximal and / or distal to the endpoints of each line to remove the overmold material 261 from the outer surfaces of the microelectrodes 229-1, 229-2, and 229-3. In some embodiments, the ablation tool may be programmed to ablate at specific locations based on programmable instructions. For example, a processor (e.g., a computer) may execute computer-executable instructions stored on a non-transitory computer-readable medium to cause the ablation tool to ablate at specific locations.

[0137] Figure 10Bshows the structure of the substrate after the ablation process step has been completed according to various embodiments of the present disclosure. Figure 10A FIG2 shows a top view of an ablation tool 270 and an ablated overmold inner lower structure 280. As shown, overmold material 261 has been removed from microelectrodes 27-1, 227-2, 227-3, 229-1, 229-2, and 229-3, exposing microelectrodes 227-1, 227-2, 227-3, 229-1, 229-2, and 229-3. In some embodiments, overmold material 261 can be removed from proximal terminal contact pads 235 in a similar manner. In some embodiments, a first side of overmold inner lower structure 260 can be ablated and flipped over, thereby ablation of a second side of the partially ablated inner lower structure. Thus, overmold material 261 can be removed circumferentially from overmold inner lower structure 260. Figure 10C A top view of an eroded overmolded inner lower structure 280 is shown after being ejected from an eroded tooling 270 , in accordance with various embodiments of the present disclosure.

[0138] Figure 11 10 illustrates mechanical properties of various materials that may be used to form the lower structure of the flexible tip portion 110 according to various embodiments of the present disclosure. In some embodiments, the lower structure may be formed of a flexible material, as described herein. In some embodiments, the flexible material may be a superelastic material, such as a Nitinol alloy. Examples of Nitinol alloys may include Nitinol alloys available from NDC; Cu-doped Nitinol alloys available from Johnson Matthey Medical Components; Nitinol alloys available from Fort Wayne Metals; and / or Nitinol alloys available from Euroflex.

[0139] In some embodiments, the flexible material forming the lower structure may include a flexible substrate. In some embodiments, as described herein, the lower structure of the flexible head end portion 110 may be formed from a flexible substrate such as a polymer and / or a printed circuit board. In some embodiments, the flexible substrate may have mechanical properties similar to those of Nitinol alloy. For example, the flexible substrate may have an elastic modulus that is equivalent to or similar to that of Nitinol alloy; an ultimate tensile strength that is equivalent to or similar to that of Nitinol alloy; a loading platform that is equivalent to or similar to that of Nitinol alloy and / or a bending strength that is equivalent to or similar to that of Nitinol alloy. In some embodiments, the flexible substrate may include a liquid crystal polymer (LCP) circuit material, such as Ultralam 3850HT available from Rogers Corporation; a glass microfiber reinforced polytetrafluoroethylene (PTFE) composite material such as that available from Rogers Corporation; Glass fiber reinforced epoxy resin laminate (FR4) according to IPC 4101C / 21 / 24 / 26 / 121 / 124 / 129; Glass fiber reinforced epoxy resin laminate (FR4) according to material characterization of two FR4 printed circuit board laminates, ETHaugan and P. Dalsjo, Norwegian Defense Research Establishment (FFI), reported on January 10, 2014; S1141 available from Shengyi Technology Co., Ltd.; FR408HR available from Isola Group; bismaleimide / triazine (BT) and epoxy resin mixtures such as BT G200 available from Isola; and / or A bismaleimide / triazine (BT) and epoxy resin mixture is commercially available as N5000-32.

[0140] In some embodiments, Figure 1A and 1B The flexible tip portion 110 shown in FIG. 1 may have an array flexure force of less than or equal to 200 grams-force. For example, to deflect the flexible tip portion 110, a force of less than or equal to 200 grams-force may be applied to the flexible tip portion. For example, when a force of less than or equal to 200 grams-force has been applied to the distal end of the flexible tip portion, the flexible tip portion may be configured as follows: Figure 1B The deflection shown, which can be formed from the materials described herein.

[0141] Figure 12A A top view of the proximal end of the inner lower structure 290 is shown in accordance with various disclosed embodiments. In some embodiments, the inner lower structure 290 can include frame locks 291-1, 291-2, 291-3, 291-4 located on the proximal end of the inner lower structure 290. It should be noted that the outer lower structure can include frame locks corresponding to the frame locks 291-1, 291-2, 291-3, 291-4 located on the inner lower structure.

[0142] Figure 12B The various embodiments of the present disclosure are shown in FIG. Figure 12AA top view of an enlarged portion of frame locks 291-1, 291-2, 291-3, 291-4 (indicated by dashed ellipse 12B) on the proximal end of the inner lower structure is shown. In some embodiments, one or more electrical connections 292-1, 292-2, ... 292-8 may be located on one or more frame locks 291-1, 291-2, 291-3, 291-4 and / or one of the lower structural arms. For example, electrical connections 292-1, 292-2, ... 292-8 may be formed on the proximal portion of the lower structural arm.

[0143] Figure 12C The various embodiments of the present disclosure are shown in Figure 12B 12C). FIG. 12A shows a top view of an enlarged portion of electrical connections 292-3 and 292-4 (represented by dashed circle 12C) shown in FIG. In some embodiments, third electrical connection 292-3 may include distal contact pad 295-1 and proximal contact pad 295-2, and fourth electrical connection 292-4 may include distal contact pad 295-4 and proximal contact pad 295-3. As described herein, the electrical connections may be located on a proximal portion of the lower structure of flexible tip portion 110. In some embodiments, the electrical connections may be insulated from the lower structure (e.g., where the lower structure is conductive) to prevent short circuits between the electrical connections. Referring to fourth electrical connection 295-4, distal contact pad 295-4 and proximal contact pad 295-3 may be electrically connected to each other via trace 296-2.

[0144] Figure 12D The present invention shows various embodiments of the present invention. Figure 12C Cross-sectional view along line mm. In some embodiments, lower structure 290 can be coated with a dielectric material 297, such as parylene. This dielectric material 297 can electrically insulate the electrical connection from the conductive lower structure 290 as described herein. In some embodiments, metallization can be applied to the surface of the dielectric to allow for secure connection of electrical connection 294-2 to lower structure 290. In an example, a metal, such as aluminum, can be deposited on the surface of dielectric material 297, and electrical connection 292-4 can be located on top of metal 298.

[0145] Figure 12E The various embodiments of the present disclosure are shown. Figure 12C292-3. In some embodiments, the distal-extending wire 300 and the proximal-extending wire 301 can be connected via the third electrical connection 292-3. In some embodiments, the distal-extending wire 300 and the proximal-extending wire 301 can be connected via the third electrical connection 292-3. In some embodiments, the distal-extending wire 300 can be soldered to the distal contact pad 295-4 and / or the proximal-extending wire 301 can be soldered to the proximal contact pad 295-3. In some embodiments, where the flexible tip does not include a conductive trace electrically connected to each microelectrode, a wire (e.g., a distal-extending wire) can be electrically connected to each microelectrode.

[0146] In some embodiments, the proximal end of the distal extension wire can be electrically connected to each electrically connected distal contact pad. Accordingly, the flexible head portion 110 can be formed into a module in which a separate distal extension wire is connected to each microelectrode at the distal end and to the electrically connected distal contact pad at the proximal end. In some embodiments, the left side of the proximal contact pad is open (e.g., the wire may not be electrically connected to the proximal contact pad) to detect the module. For example, each proximal contact pad can be probed by an electrical detection device to determine whether there is continuity and to determine that the signal noise associated with each microelectrode and the associated distal extension wire does not exceed a specified amount. This can be done before assembling the entire high-density electrode mapping catheter 101.

[0147] In contrast, some existing methods assemble the entire high-density electrode mapping catheter 101 before performing testing. In addition, the electrical connector can reduce the complexity associated with connecting the proximal-extending wire and the distal-extending wire of the high-density electrode mapping catheter 101. For example, the proximal end of the distal-extending wire can be coupled to the distal pad of the electrical connection and the distal end of the proximal-extending wire can be coupled to the proximal pad of the electrical connection, rather than directly connecting the proximal and distal-extending wires.

[0148] In some embodiments, a prefabricated substrate (e.g., a curved substrate) may be used, wherein the prefabricated substrate includes electrical connections and can be bonded to a lower structure (e.g., a parylene coated frame). In an example, the substrate design may mimic a reference Figures 12B to 13B The basic electrical connection configuration described and shown. This allows the density of microelectrodes on the array formed by the flexible tip 110 to be increased by forming a multi-layer substrate (e.g., the number of microelectrodes can be increased from 22 to 32 to 64). In some embodiments, the prefabricated substrate can be attached to the lower structure using an adhesive material such as epoxy.

[0149] Figure 13AA top view of multiple electrical connections located on the first inner arm 310, second inner arm 311, first outer arm 312, and second outer arm 313 of the flexible frame of the flexible tip 110 of a high-density electrode mapping catheter 101, according to various embodiments of the present disclosure, is shown. The multiple electrical connections are generally discussed with reference to electrical connections 314-1, 314-2, 314-3, and 314-4. As described in references 12A to 12E, the electrical connections may be located on a frame lock (e.g., frame lock 315) and / or on the proximal portions of arms 310, 311, 312, and 314. In some embodiments, the number of electrical connections provided on each frame lock may range from 1 to 10. The electrical connection density may be increased depending on the target device size and pad / trace conductors and space requirements. If the design provides sufficient footprint, the number of connections may be increased as needed. Referring to the first electrical connection 314-1, each electrical connection may include a proximal contact pad and a distal contact pad electrically connected via trace 317. For example, as described herein, the first electrical connection 314 - 1 may include a distal contact pad 316 - 1 and a proximal contact pad 316 - 2 connected by a trace 317 .

[0150] In some embodiments, a plurality of distal extension wires, such as distal extension wire 321, may extend distally along the flexible frame of the high-density electrode mapping catheter 101. Figure 13B As shown, the proximal end of each distally extending wire can be electrically connected to a distal contact pad of each electrical connection (eg, distal contact pad 316-1). As described herein, the connection of the distal end of each distally extending wire can form a single module that can be tested.

[0151] In some embodiments, each arm may extend through a torsion pad 320, which may be configured to maintain alignment between the arms. 9A to 10C As described above, overmolding and erosion processes may be employed, which may overmold each arm of the flexible frame (e.g., arms 310, 311, 312, 314) and the torsion pad 320. Figure 1A and 1B The connector 108 shown in FIG. 1 may also be overmolded. In some embodiments, the overmolding material may include the

[0152] Figure 13B The present invention shows various embodiments of the present invention. Figure 13AFIGURE 1 illustrates a top view of a portion of a subset of electrical connections on the first inner arm 310, the second inner arm 311, the first outer arm 312, and the second outer arm 313 of the flexible frame of the flexible tip portion 110 of the high-density electrode mapping catheter 101. The subset of electrical connections generally refers to electrical connections 314-1, 314-2, 314-3, and 314-4. In an example, the proximal end of each of a plurality of distally extending wires can be electrically connected to a corresponding one of the plurality of distal contact pads of each of the plurality of electrical connections, and the distal end of each of a plurality of proximally extending wires can be electrically connected to a corresponding one of the proximal contact pads of each of the plurality of electrical connections. For example, with specific reference to electrical connection 314-2, distally extending wire 330, and proximally extending wire 331, the proximal end of distally extending wire 330 can be electrically connected to distal contact pad 316-1, and the distal end of proximally extending wire 331 can be electrically connected to proximal contact pad 316-2 of electrical connection 314-2. Contact pads 316 - 1 , 316 - 2 may be electrically connected by trace 317 as described herein, and thus conductive lines 330 , 331 may be electrically connected to each other.

[0153] Figure 14 A process flow chart 340 is shown for forming an integrated electrode structure including a conductive substructure according to various embodiments of the present disclosure. In some embodiments, the method may include coating a flexible frame of a flexible head portion of the integrated electrode structure with a first dielectric material in step 331. In step 332, the trace pattern on the coated flexible frame may be masked with a masking material to form a masked portion and an unmasked trace pattern portion. In some embodiments, in step 333, a seed layer is deposited on the unmasked trace pattern portion. In step 334, the method may include electroplating the seed layer with a conductive material to form a conductive trace. In step 335, the method may include stripping the masking material from the masked portion.

[0154] In step 336, the method may include coating the conductive trace with a second dielectric material. In step 337, the method may include stripping the second dielectric material from the distal portion of the conductive trace. In step 338, the method may include electrically connecting the microelectrode to the distal portion of the conductive trace. As described herein, electrically connecting the microelectrode to the distal portion of the conductive trace may include masking the flexible frame of the integrated electrode structure proximally and distally relative to the distal portion of the conductive trace to form a mask-defining region; depositing a second seed layer on the mask-defining region; and electroplating the mask-defining region with a conductive material to form the microelectrode. In some embodiments, the masked portion of the flexible frame may be stripped of the masking material as described herein. In some embodiments in which the microelectrode will extend circumferentially around the flexible frame, the method may include circumferentially masking the flexible frame of the integrated electrode structure proximally and distally relative to the distal portion of the conductive trace to form a circumferential mask-defining region.

[0155] In some embodiments, the microelectrode is not formed by an electroplating process (e.g., depositing a conductive material to form the microelectrode), but rather is formed by electrically connecting a hollow cylindrical ferrule to a distal portion of a conductive trace, wherein the hollow cylindrical ferrule is coaxial with a flexible frame of the flexible tip. In some embodiments, electrically connecting the hollow cylindrical ferrule to the distal portion of the conductive trace may include depositing solder on the distal portion of the conductive trace; aligning the hollow cylindrical ferrule coaxially with the distal portion of the conductive trace and the flexible frame; and reflowing the solder to electrically connect the hollow cylindrical ferrule to the distal portion of the conductive trace.

[0156] Figure 15 A flow chart 350 of a process for forming an integrated electrode structure including a substrate substructure according to various embodiments of the present disclosure is shown. In some embodiments, in step 351, the method may include coating a flexible frame substrate at a flexible tip end portion of the integrated electrode structure with a conductive material. In some embodiments, the flexible frame may be formed from a flexible substrate. In step 352, the method may include masking a trace pattern on the coated flexible frame with a masking material to form a masked trace pattern portion and an unmasked portion. In step 353, the method may include etching the unmasked portion to expose the flexible frame substrate. In some embodiments, in step 354, the method may include stripping the masking material from the masked trace pattern portion to expose the conductive trace. In step 355, the method may include coating the conductive trace with a dielectric material. In some embodiments, in step 356, the method may include stripping the dielectric material from a distal portion of the conductive trace. In step 357, the method may include electrically connecting a microelectrode to the distal portion of the conductive trace.

[0157] As described herein, in some embodiments, the method further comprises treating with a polymer such as Overmolding the Integrated Electrode Structure As described herein, in some embodiments, the overmolding can be removed from the outer surface of the microelectrode by an ablation step.

[0158] Figure 16 A side view of an arm 369 of a high-density electrode mapping catheter according to various embodiments of the present disclosure is shown. In some embodiments, a dielectric material 371 can coat a lower structure 370 of the arm 369 of the high-density electrode mapping catheter. In some embodiments, as described herein, one or more conductive traces 372 can be formed on an outwardly facing surface (facing away from the lower structure 370) of the dielectric material 371. For example, in a manner similar to that discussed herein, a mask can be applied to the dielectric material 371 to form unmasked trace pattern portions. A seed layer can be applied to coat the unmasked trace pattern portions. The conductive traces 372 can be formed on top of a seed layer, which can bond the conductive traces 372 to the dielectric material 371.

[0159] In some embodiments, as Figure 16 As shown, multiple layers of conductive traces 372 can be formed on an arm 369 of a high-density electrode mapping catheter. One or more additional conductive traces 373 can be formed on a second dielectric material layer 374. The second dielectric material layer 374 can be applied over the first dielectric material layer 371 and the conductive traces 372. In some embodiments, a first via 375 can be formed within the dielectric material 374 coating the conductive traces 372. In an example, a mask can be applied over portions of the conductive traces 372 (e.g., portions where the via 375 will be formed) before applying the second dielectric material layer 374 and / or removing the second dielectric material 374 layer to create the first via 375. Additional conductive traces can be constructed in this manner.

[0160] In some embodiments, additional conductive trace 373 can be applied over a portion of second dielectric material layer 374. In an example, the distal end of the additional conductive trace can be disposed proximally relative to first via 375. In some embodiments, additional conductive trace 373 and conductive trace 372 can extend parallel to each other and to lower structure 370. In some embodiments, third dielectric material layer 376 can coat a portion (e.g., toward the outer surface) of second dielectric material layer 374 and additional conductive trace 373. In some embodiments, a mask can be applied over additional conductive trace 373 (e.g., the portion where via 377 will be formed) before applying third dielectric material layer 376 and / or removing the third dielectric material layer to create via 377 for second conductive trace 373.

[0161] In some embodiments, the mask applied to conductive trace 372 may be removed after applying third dielectric material layer 376 to create first via 375 within second dielectric material layer 374 and second via 378 within third dielectric material layer 376 to form via 379. Figure 16 As shown, multiple layers of conductive traces 372, 373 may be formed on the lower structure 370 of the arm 369. As described herein, this is advantageous when the footprint associated with the surface of the arm 369 is not large enough to support forming more than a certain number of conductive traces adjacent to each other. Accordingly, some embodiments of the present disclosure may allow for the formation of conductive traces in different layers.

[0162] In some embodiments, similar structures can be formed on the other side of lower structure 370 of arm 369. For example, as described herein, the other side of arm 369 (e.g., the opposite side of arm 369 relative to conductive traces 372, 373) can include similar structures that support conductive traces formed in a different layer.

[0163] Figures 17A to 17E A side view of the lower structure of an arm of a high-density electrode mapping catheter and related processing steps are shown according to various embodiments of the present disclosure. Figure 17A The lower structure 385-1 of the arm of the high-density electrode mapping catheter is shown. Figure 17B As shown, in some embodiments, a first passage 386-1 and a second passage 386-2 may be formed in the lower structure 385-2. In an example, the passages 386-1 and 386-2 may be cut by laser, drilling, etc. Figure 17C As shown, for example, in some embodiments, lower structure 385 - 2 may be coated with a first coating 387 of a dielectric material such as parylene.

[0164] like Figure 17D As shown, conductive trace 388 may be applied over first dielectric material coating 387 coating lower structure 385-2. In some embodiments, conductive trace 388 may be applied to both the top and bottom surfaces of first dielectric material coating 387 coating lower structure 352-2. Conductive trace 388 may fill via 386-2, thereby electrically connecting the bottom portion of conductive trace 388 applied to the bottom surface associated with first dielectric material coating 387 and the top portion of conductive trace 388 applied to the top surface associated with first dielectric material coating 387. In some embodiments, conductive trace 388 may extend proximally relative to via 386-2. In some embodiments, conductive trace 388 may extend distally relative to second via 386-2. For example, as shown in FIG. Figure 17D As shown, the distal end of the conductive trace 388 is located between the first via 386 - 1 and the second via 386 - 2 .

[0165] like Figure 17E As shown, a second dielectric coating 390 can be applied to the top and bottom surfaces of the first dielectric coating 387 and the conductive trace 388. In some embodiments, the second dielectric coating 390 cannot be applied to the first via 386-1 and / or can be removed from the first via 386-1. FIG. 17F shows a processed lower structure 392 including a second conductive trace 391 applied to the top and bottom surfaces of the second dielectric coating 390. In some embodiments, as Figure 17F As shown, a second conductive trace 391 can be applied to the portion of the first dielectric coating 387 surrounding the first via 386-1 that is not coated with the second dielectric coating 390. In an example, the second dielectric coating 390 can be applied proximally or distally relative to the first via 386-1, leaving the first dielectric coating 387 exposed for coating the second conductive trace 391. The second conductive trace 391 can extend along the top and bottom of the processed lower structure 392. The second conductive trace 391 can extend through the via 386-1, thereby electrically connecting the portions of the second conductive trace 391 extending along the top and bottom of the processed lower structure 392.

[0166] In some embodiments, first conductive trace 388 may be laterally offset from second conductive trace 391. This may create a via within second dielectric coating 390 that can be used to electrically connect a microelectrode or other device to first conductive trace 388 while electrically insulating the microelectrode or other device from second conductive trace 391. In some embodiments, a third dielectric coating may be applied to second conductive trace 391, and a microelectrode may be electrically connected to second conductive trace 391 through the via formed in the third dielectric coating.

[0167] Figures 18A to 18G The present invention shows various embodiments of the present invention. Figure 1A A top view of an embodiment of the lower structure of a high-density electrode mapping catheter. Figures 18A to 18G The illustrated embodiments may be constructed from a single piece of material. Figure 18A The lower structure 410 is shown to include an inner lower structure 411 (also referred to herein as the inner lower structure) and an outer lower structure 412 (also referred to herein as the outer lower structure), which can be formed from a single piece of material. In some embodiments, the inner lower structure 411 and the outer lower structure 412 can be laser cut from a single piece of material and / or photolithographically formed from a single piece of material.

[0168] like Figure 18A18A , the distal end of the inner lower structure 411 can be connected to the distal end of the outer lower structure 412 by a connecting portion 413. The connecting portion 413 can be formed from the same integral piece of material as the inner lower structure 411 and the outer lower structure 412. The connecting portion 413 can extend from the distal side of the distal end of the inner lower structure 411 to the proximal side of the distal end of the outer lower structure 412. In some embodiments, the connecting portion 413 is flat and has the same thickness as the inner lower structure 411 and the outer lower structure 412. As shown in FIG. 18A , the connecting portion can extend between the distal end of the inner lower structure 411 and the distal end of the outer lower structure 412, on either side of the lower structure longitudinal axis nn defined by the inner lower structure 411 and the outer lower structure 412.

[0169] like Figure 18A As shown, the outer edges 415-1, 415-2 can be rounded toward the longitudinal axis n of the substructure. In some embodiments, as the substructure 410 is inserted into and / or deployed from the sheath, the rounded outer edges 415-1, 415-2 can help reduce strain between the inner substructure 411 and the outer substructure 412. For example, in some embodiments where the outer edges are straight rather than rounded, portions of the outer edges of the inner and outer substructures 411, 412 adjacent to the connection 413 may experience increased strain. Conversely, as the substructure 410 is deflected and / or inserted into or deployed from the sheath, the rounded outer edges 415-1, 415-2 can better distribute strain.

[0170] Figure 18B An embodiment of a substructure 420 is shown that includes an inner substructure 421 and an outer substructure 422. Figure 18B As shown, the distal end of the inner lower structure 421 can be connected to the distal end of the outer lower structure 422 via a connecting portion 423. The connecting portion 423 can be formed from the same integral piece of material as the inner lower structure 421 and the outer lower structure 422. In some embodiments, the connecting portion 423 can extend from the distal side of the distal end of the inner lower structure 421 to the proximal side of the distal end of the outer lower structure 422.

[0171] In some embodiments, the connecting portion 423 may be flat and may have the same thickness as the inner lower structure 421 and the outer lower structure 422. Figure 18B As shown, the connection portion 423 may extend between the distal end of the inner lower structure 421 and the distal end of the outer lower structure 422 on either side of the lower structure longitudinal axis oo defined by the inner lower structure 421 and the outer lower structure 422. Figure 18AIn contrast, for reasons described herein, the connection 423 may not extend as far on either side of the substructure longitudinal axis oo. Figure 18A As described, the connecting portion may include rounded outer edges 425-1, 425-2, which may better distribute strain between the inner lower structure 421, the connecting portion 423, and the outer lower structure 422 as the lower structure 420 is deflected and / or inserted into or deployed from the sheath. In some embodiments, because the connecting portion 423 does not extend as far on either side of the lower structure longitudinal axis oo, the lower structure may be deflected with less force and / or more easily introduced into and / or deployed from the sheath in some embodiments.

[0172] In some embodiments, the lower structure 420 may include first and second external connectors 426-1 and 426-2 that connect the distal expansion head 427 of the inner lower structure 421 to the outer lower structure 422. For example, the distal expansion head 427 may include a first expansion segment 428-1 that expands away from the lower structure longitudinal axis oo and a second expansion segment 428-2 that expands away from the lower structure longitudinal axis oo. In some embodiments, the first external connector 426-1 may connect the first expansion segment 428-1 to the outer lower structure 422, and the second external connector 426-2 may connect the second expansion segment 428-2 to the outer lower structure 422. The first and second external connectors 426-1 and 426-2 may be connected to the outer lower structure 422 at points on the outer lower structure adjacent to corresponding first and second expansion segments 428-1, 428-2.

[0173] In some embodiments, the first connector 426-1 can expand toward the connecting portion 423, and in some embodiments, the second connector 426-2 can expand toward the connecting portion 423. Alternatively, the first and second connectors 426-1, 426-2 can expand away from the connecting portion 423. By expanding the connectors 426-1, 426-2, the members can be lengthened or shortened (e.g., slack can be built into the connectors 426-1, 426-2) as the lower structure is deflected and / or inserted into or deployed from the sheath. For example, as the lower structure 420 is introduced into the sheath, the outer lower structure 422 can be compressed toward the lower longitudinal axis oo, causing an increase in axial length. To compensate for this increase in axial length, the expanded distal head 427 is straightened (becomes less expanded) as the outer lower structure 422 is compressed and lengthened. This can effectively increase the length of the inner lower structure 421 and prevent the inner lower structure 421 from stretching on the outer lower structure 422, thereby preventing the outer lower structure 421 from getting caught within the sheath. As the inner lower structure 421 straightens and lengthens, the first and second connectors 426-1, 426-2 can straighten (become less expanded) and lengthen to allow the outer lower structure 422 to lengthen. In some embodiments, as the outer lower structure 422 is compressed, the first and second connectors 426-1, 426-2 can help pull on the first and second expansion sections 428-1, 428-2 of the distal expansion head 427 and cause the distal expansion head 427 to lengthen with the outer lower structure 422.

[0174] Figure 18C The lower structure 430 is shown to include an inner lower structure 431 and an outer lower structure 432, which can be formed from a single piece of material. In some embodiments, the inner lower structure 431 and the outer lower structure 432 can be laser cut from a single piece of material and / or photolithographically formed from a single piece of material. Figure 18C As shown, the distal end of the inner lower structure 431 can be connected to the distal end of the outer lower structure 432 by a connecting portion 433. The connecting portion 433 can be formed from the same integral piece of material as the inner lower structure 431 and the outer lower structure 432. The connecting portion 433 can extend from the distal side of the distal end of the inner lower structure 431 to the proximal side of the distal end of the outer lower structure 432. In some embodiments, the connecting portion 433 can be flat and can have the same thickness as the inner lower structure 431 and the outer lower structure 432. Figure 18C As shown, the connection portion 423 may extend between the distal end of the inner lower structure 431 and the distal end of the outer lower structure 432 on either side of the lower structure longitudinal axis pp defined by the inner lower structure 431 and the outer lower structure 432 .

[0175] like Figure 18CAs shown, the connecting portion 433 may extend from the lower structure longitudinal axis pp to the outermost portions of the first and second expansion segments 436-1, 436-2. Figure 18C As shown, the connection portion 433 may extend from the lower structure longitudinal axis pp to a point distal to the outermost portions of the first and second expansion segments 436-1, 436-2. Figure 18A As described, the connecting portion 433 may include rounded outer edges 435-1, 435-2 that may better distribute strain as the lower structure 430 is deflected and / or inserted into or deployed from a sheath.

[0176] Figure 18D The lower structure 440 is shown to include an inner lower structure 441 and an outer lower structure 442, which may be formed from a single piece of material. In some embodiments, the inner lower structure 441 and the outer lower structure 442 may be laser cut from a single piece of material and / or photolithographically formed from a single piece of material. Figure 18D As shown, the distal end of the inner lower structure 441 can be connected to the distal end of the outer lower structure 442 by connecting portions 443-1, 443-2. ​​The connecting portions 443-1, 443-2 can be formed from the same integral material as the inner lower structure 441 and the outer lower structure 442. The connecting portions 443-1, 443-2 can extend from the distal side of the distal end of the inner lower structure 441 to the proximal side of the distal end of the outer lower structure 442. In some embodiments, the connecting portions 443-1, 443-2 can be flat and can have the same thickness as the inner lower structure 441 and the outer lower structure 442. Figure 18D As shown, the connecting portions 443 - 1 , 443 - 2 may extend between the distal ends of the inner lower structure 441 and the outer lower structure 442 , on either side of a lower structure longitudinal axis qq defined by the inner lower structure 441 and the outer lower structure 442 .

[0177] like Figure 18DAs shown, the first connection portion 443-1 may extend between a first distally inclined section 448-1 of the inner lower structure 441 and a corresponding section of the outer lower structure 442. The second connection portion 443-2 may extend between a second distally inclined section 448-2 of the inner lower structure 441 and a corresponding section of the outer lower structure 442. In some embodiments, the side of the first connection portion 443-1 located toward the lower structure longitudinal axis qq may include an inner edge 444-1 that is rounded away from the lower structure longitudinal axis qq, and the side of the second connection portion 443-2 located toward the lower structure longitudinal axis qq may include an inner edge 444-2 that is rounded away from the lower structure longitudinal axis qq, thereby defining a space 449 between the inner edges 444-1 and 444-2 of the connections 443-1 and 443-2 and the distal ends of the inner and outer lower structures 441 and 442. In some embodiments, the gap 449 may allow for greater flexibility of the lower structure 440 as the lower structure is deflected and / or inserted into the sheath and / or deployed from the sheath. Figure 18A As described, the connecting portions 443-1, 443-2 may include outer edges 445-1, 445-2 that are rounded toward the distal end of the lower structure 440. The rounded inner edges 444-1, 444-2 and the rounded outer edges 445-1, 445-2 may better distribute strain as described herein.

[0178] Figure 18E An embodiment of a lower structure 450 is shown that includes an inner lower structure 451 and an outer lower structure 452. In some embodiments, the lower structure 450 may include first and second external connectors 456-1, 456-2 that connect a distal expansion head 457 of the inner lower structure 451 to the outer lower structure 452. For example, the distal expansion head 457 may include a first expansion segment 458-1 that expands away from the lower structure longitudinal axis rr and a second expansion segment 458-2 that expands away from the lower structure longitudinal axis rr. In some embodiments, the first external connector 456-1 may connect the first expansion segment 458-1 to the outer lower structure 452, and the second external connector 456-2 may connect the second expansion segment 458-2 to the outer lower structure 452. The first and second external connectors 456-1, 456-2 may connect to the outer lower structure 452 at points on the outer lower structure adjacent to corresponding ones of the first expansion segment 458-1 and the second expansion segment 458-2.

[0179] In some embodiments, the first connector 456-1 can expand toward the distal ends of the inner and outer lower structures 451, 452, and in some embodiments, the second connector 456-2 can expand toward the distal ends of the inner and outer lower structures 451, 451. Alternatively, the first and second connectors 456-1, 456-2 can expand away from the distal ends of the inner and outer lower structures 451, 451. As described herein, by expanding the connectors 456-1, 456-2, the lower structure 450 can be lengthened or shortened as the structure is deflected and / or inserted into or deployed from a sheath.

[0180] Figure 18F An embodiment of a lower structure 460 is shown that includes inner lower structures 461-1, 461-2 and an outer lower structure 462. In some embodiments, the lower structure 460 may include first and second outer connectors 466-1, 466-2 that connect distal expansion heads 467 of the inner lower structures 461-1, 461-2 to the outer lower structure 462. Figure 18E In contrast, the internal lower structures 461-1, 461-2 may terminate at the first and second expansion segments 468-1, 468-2 and may not extend distally from the first and second expansion segments 468-1, 468-2. As shown, the internal lower structures 461-1, 461-2 extend proximally from the first and second expansion segments 468-1, 468-2. In some embodiments, a first external connector 466-1 may connect the first expansion segment 468-1 to the external lower structure 462, and a second external connector 466-2 may connect the second expansion segment 468-2 to the external lower structure 462. The first and second external connectors 466-1, 466-2 may be connected to the external lower structure 462 at points adjacent to a corresponding first and second expansion segments 468-1, 468-2.

[0181] In some embodiments, the first connector 466-1 can expand toward the distal ends of the inner and outer lower structures 461-1, 461-2, 462, and in some embodiments, the second connector 466-2 can expand toward the distal ends of the inner and outer lower structures 461-1, 461-2, 462. Alternatively, the first and second connectors 461-1, 461-2 can expand away from the distal ends of the inner and outer lower structures 461-1, 461-2, 462. As described herein, by expanding the connectors 466-1, 466-2, the lower structure 460 can be lengthened or shortened as the structure is deflected and / or inserted into or deployed from a sheath.

[0182] Figure 18GAn embodiment of a lower structure 470 is shown that includes inner lower structures 471-1, 471-2 and an outer lower structure 472. In some embodiments, the first and second arms of the inner lower structures 471-1, 471-2 can extend distally from the proximal end of the lower structure 470. The distal portions of the first and second arms of the inner lower structures 471-1, 471-2 can extend parallel to the lower structure longitudinal axis tt and terminate proximally relative to a corresponding one of the first and second rounded sections 473-1, 473-2 of the outer lower structure 472. In some embodiments, connecting arms 474-1, 474-2, ... 474-6 can extend from the first and second arms of the inner lower structures 471-1, 471-2 transversely to the lower structure longitudinal axis tt and extend away from the lower structure longitudinal axis tt toward the outer lower structure 472. The connecting arms 474 - 1 , 474 - 2 , … 474 - 6 may be connected to the inner lower structures 471 - 1 , 471 - 2 and the outer lower structure 472 .

[0183] Figure 19AA top view of a flexible tip portion 500 of a high-density electrode mapping catheter including a plurality of microelectrodes 502-1, 502-2, ..., 502-16 according to various embodiments of the present disclosure is shown. The plurality of microelectrodes 502-1, 502-2, ..., 502-16 are collectively referred to as microelectrodes 502 (also referred to herein as electrodes) hereinafter. In some embodiments, the flexible tip portion 500 forms a flexible array of microelectrodes 502 that is located at the distal end of the catheter shaft. This planar array (or "paddle-like configuration") of microelectrodes 502 includes four side-by-side longitudinally extending arms 504, 506, 508, 510 that can form a flexible frame on which the microelectrodes 502 are placed. The four microelectrode-carrying arms include a first lateral arm 504, a second lateral arm 510, a first medial arm 506, and a second medial arm 508. These arms are laterally separated from each other. The inner portion of the flexible tip 500 may include an expanded head 512, and the outer portion of the flexible tip 500 may include a head 514. As previously described, the first outer arm 504 and the second outer arm 510 may be part of the outer lower structure, and the first inner arm 506 and the second inner arm 508 may be part of the inner lower structure. The first and second inner arms 506, 508 and the expanded head 512 may form an inner arm lower structure comprising elements with a flat cross-section, while the first and second outer arms 504, 510 and the head 514 may form an outer arm lower structure comprising elements with a flat cross-section. In some embodiments, the flexible tip 500 may be formed from a flexible metal such as Nitinol. In some embodiments, the flexible tip 500 may be formed from a flexible printed circuit board. In some embodiments, the flexible tip 500 may include a mounting portion 516. In some examples, the first and second outer arms 504, 510 and the first and second inner arms 506, 508 may be connected to the mounting portion 516. In some embodiments, the mounting portion 516, first and second outer arms 504, 510, first and second inner arms 506, 508, dilating head 512, and head 514 can all be formed from a single piece of material. In some embodiments, the mounting portion 516 can be inserted into the distal end of a catheter shaft.

[0184] In some embodiments, the flexible tip portion 500 may include a plurality of conductive traces 518-1, 518-2, 518-3, and 518-4 disposed along the mounting portion 516, the first and second outer arms 504 and 510, the first and second inner arms 506 and 508, the expanded head 512, and / or the head 514. Hereinafter, the conductive traces 518-1, 518-2, 518-3, and 518-4 are collectively referred to as conductive traces 518. Each conductive trace 518 may be electrically connected to one of the microelectrodes 502. For example, the first microelectrode 502-1 may be electrically connected to the first conductive trace 518-1, the second microelectrode 502-2 may be electrically connected to the second conductive trace 518-2, the third microelectrode 502-3 may be electrically connected to the third conductive trace 518-3, and / or the fourth microelectrode 502-4 may be electrically connected to the fourth conductive trace 518-4. Although there are more than four traces located on the flexible tip, for clarity only traces 518 - 1 , 518 - 2 , 518 - 3 , and 518 - 4 are discussed herein.

[0185] In some embodiments, the traces 518 and / or microelectrodes 502 can be formed as described above. In some embodiments, the traces 518 and / or microelectrodes 502 can be formed as described above. Figures 23A to 23F As shown, the first trace 518-1 can extend from the proximal side of the first microelectrode 502-1.

[0186] In some embodiments, as further discussed herein, each trace 518 can be electrically connected to a corresponding microelectrode 502 via a pathway. As shown, the microelectrodes 502 can be placed along the longitudinal length of each arm. In some embodiments, the trace 518 can be routed around each microelectrode 502 so that the trace 518 is not electrically connected to the microelectrode 502 to prevent contact with these electrodes and thereby prevent a short circuit. In an example and as shown, a second conductive trace 518-2 can be routed around the first microelectrode 502-1 to avoid contact with the first microelectrode 502-1. The second conductive trace 518-2 can extend along the inside of the first microelectrode 502-1 and can be coupled to the second microelectrode 502-2. The third trace 518-3 can be routed around the outside of the first microelectrode 502-1 and the second microelectrode 502-2 and can be coupled to the third microelectrode 502-3. The fourth trace 518-4 can be routed around the inner sides of the first microelectrode 502-1, the second microelectrode 502-2, and the third microelectrode 502-3 and can be connected to the fourth microelectrode 502-4. In the example shown, the traces associated with each longitudinally alternating microelectrode 502 can be routed around alternating sides of the microelectrode 502. For example, the second trace 518-2 associated with the second microelectrode can be routed on the inner side of the first microelectrode 502-1; the third trace 518-3 associated with the third microelectrode 502-3 can be routed on the outer sides of the first and second microelectrodes 502-1 and 502-3; and the fourth trace 518-4 associated with the fourth microelectrode 502-4 can be routed on the inner sides of the first microelectrode 502-1, the second microelectrode 502-2, and the third microelectrode 502-3. This would allow the traces 518 to be more evenly distributed on either side of the microelectrode 502, thereby allowing the microelectrodes 502 to be more evenly spaced in the middle of each arm.

[0187] In some embodiments, each trace 518 can be routed proximally along each arm 504, 506, 508, 510 to the mounting portion 516. In some embodiments, the mounting portion 516 can include a plurality of contact pads 520-1, 520-2, ..., 520-9, hereinafter collectively referred to as contact pads 520, arranged in a first row 522-1 and a second row 522-2. For clarity, only contact pads 520-1, 520-2, ..., 520-9 will be discussed. In some embodiments, the proximal end of each trace 518 can terminate at a corresponding contact pad 520.

[0188] In some embodiments, each row of contact pads 522-1, 522-2 may diverge along the longitudinal axis of the flexible tip 500. In an example, as each row of contact pads 522-2, 522-2 extends distally, each row of contact pads 522-2, 522-2 may extend away from the longitudinal axis of the flexible tip 500. Accordingly, each row of contact pads 522-2, 522-2 may extend laterally away from each other as the row extends distally. In some embodiments, each row of contact pads 522-2, 522-2 may be linear. In an example, the mounting portion 516 may have a limited lateral width. Accordingly, the contact pads 520 may be longitudinally and laterally staggered relative to each other. For example, from the distal end to the proximal end of the mounting portion 516, the contact pads 520 may be longitudinally staggered toward the proximal end and laterally staggered toward the longitudinal axis of the flexible tip 500.

[0189] In some embodiments, trace 518-3 may be connected to the proximal end of contact pad 520-1. Accordingly, contact pad 520-1 may be electrically connected to microelectrode 502-3. In some embodiments, a detection trace may extend proximally relative to one or more contact pads 520. For example, a detection trace may extend proximally relative to contact pad 520-1. The detection trace may form a detection portion (not shown) including a larger contact detection pad, which may be detected by a detection device to ensure continuity between contact pad 520-1, electrical trace 518-3, and microelectrode 502-3. In some embodiments, the contact detection pad may be electrically connected to each contact pad 520 via the detection trace. In some embodiments, the detection trace may extend proximally from each detection pad 520. As shown, the longitudinal and transverse divergence of the detection pads 520 allows the electrical trace to extend distally from each contact pad 520, and allows the detection trace to extend proximally from each contact pad.

[0190] Figure 19B The various embodiments of the present disclosure are shown in FIG. Figure 19AFIG2 is an enlarged top view of a pair of contact pads 520-8 and 520-9 on the flexible tip end shown in FIG2 . In some embodiments, the contact pads 520 may be formed of a conductive material. For example, the contact pads 520 may be formed of copper, gold, or the like. In some embodiments, the lateral width of the contact pads 520 is approximately 0.2 mm, however, the contact pads may have a smaller or larger lateral width. In some embodiments, the longitudinal length of the contact pads 520 is approximately 0.45 mm, however, the contact pads may have a shorter or longer longitudinal length. As shown, conductive traces 518-5 and 518-6 may extend distally from the contact pads 520-8 and 520-9 and may be electrically connected to the contact pads 520-8 and 520-9, respectively. For example, the conductive traces 518-5 and 518-6 may electrically connect the contact pad 520-8 to the microelectrode 502-8 and the contact pad 520-9 to the microelectrode 502-12, respectively. In certain embodiments, as described above, contact pads 520-8, 520-9 may include test traces 532-8, 532-9 extending proximally from each contact pad 520-8, 520-9 respectively. As shown, other detection traces 532-4, 532-5, 532-6, 532-7, 532-8 may extend longitudinally along mounting portion 516. In certain embodiments, detection traces 532 may be spaced apart laterally by about 0.05 millimeters, but in certain embodiments, detection traces may be spaced apart by a distance that is smaller or larger. In certain embodiments, the lateral width of the detection traces is about 0.03 millimeters, but the detection traces may have a lateral width that is greater than or less than 0.03 millimeters.

[0191] Figure 19C The various embodiments of the present disclosure are shown in FIG. Figure 19A , an enlarged top view of a microelectrode 502-1 on a flexible tip portion 500 is shown in FIG. In some embodiments, the microelectrode 502-1 may have a conductive trace 518-1 extending proximally from the microelectrode 502-1. In some embodiments, the microelectrode 502-1 may have a longitudinal length in the range of 0.1 to 5 mm and a lateral width in the range of 0.1 to 5 mm. However, in some embodiments, the microelectrode 502-1 may have a longitudinal length of approximately 0.92 mm and a lateral width of approximately 0.9 mm. However, in some embodiments, the microelectrode 502-1 may have a longitudinal length of approximately 0.92 mm and a lateral width of approximately 0.3 mm. As shown, the conductive trace may extend on either side of the microelectrode 502-1, connecting the other microelectrodes 502 to a corresponding one of the contact pads 520.

[0192] Figure 19D The various embodiments of the present disclosure are shown in FIG. Figure 19AA side view of the microelectrodes on the top and bottom of the flexible tip 500 is shown. Figure 19A The top of the flexible tip end portion 500 is shown with the microelectrode 502 located on the first outer arm 504. In some embodiments, the bottom of the flexible tip end portion 500 can include the same features as the top of the flexible tip end portion 500. For example, Figure 19D As shown, the bottom portion of the flexible tip 500 may also include microelectrodes 502-17, 502-18, 502-19, and 502-20, collectively referred to below as microelectrodes 502, conductive traces 518 (not shown), contact pads 520 (not shown), and the like. In examples, this allows for investigation of different monopolar and bipolar electrographic configurations. In examples, when electrodes disposed on the top of the flexible tip 500 are placed against tissue while electrodes at the bottom of the flexible tip 500 are placed in a pool of blood, or vice versa, different electrical signals may be received by the top electrodes than by the bottom electrodes. In some embodiments, the signals (e.g., impedance) received by the top electrodes may be analyzed with reference to the signals (e.g., impedance) received by the bottom electrodes to determine whether the flexible tip 500 is in contact with tissue. In some embodiments, the degree of contact between the flexible tip 500 and associated microelectrodes 502 and tissue may be determined based on analysis of signals received from the bottom and top electrodes. In an example, when the signals received from the bottom electrode and the top electrode are the same, this indicates that the entire flexible tip 500 is located in the blood pool and is not in contact with tissue.

[0193] In an example, a bipolar configuration employing this "bottom minus top" configuration can produce an electrogram that is significantly different in morphology than a bipolar electrogram employing a "bottom minus adjacent bottom" configuration. For example, some medical devices used to generate electrograms receive electrical signals from electrodes that are adjacent to each other and located on the same side of the medical device. Electrograms generated by devices of the present disclosure, such as those that include electrodes on both sides (e.g., top and bottom) of a device (e.g., flexible tip 500), can produce significantly different electrograms.

[0194] like Figure 19D As described above, the microelectrode 502 can be located on the top and / or bottom of the flexible tip 500. For example, the microelectrode 502 can be located on the first outer arm 504, the second outer arm 510 ( Figure 19A ), the first inner arm 506 ( Figure 19A ) and / or the second inner arm 508 ( Figure 19A) on the top and / or bottom of the flexible tip portion 500. Each top microelectrode 502 may have a vertically adjacent bottom microelectrode 502. In an example, the first top microelectrode 502-1 may be vertically adjacent to the bottom electrode 502-17 located directly below the first top microelectrode 502-1. In some embodiments, the vertical spacing (V) between the outer surfaces of each microelectrode 502 on the top and bottom of the flexible tip portion 500 is S ) can be in the range of 0 to 3 mm. In some embodiments, the vertical spacing (V) between the outer surfaces of each microelectrode 502 on the top and bottom of the flexible tip 500 is S ) may be approximately 0.22 mm. The vertical spacing V between the microelectrodes 502 located on the top and those located on the bottom S A third dimension may be provided between the microelectrodes 502 to enable the microelectrodes 502 on the top and bottom of the flexible tip 500 to receive extracellular matrix (ECM) signals.

[0195] Some medical devices may include electrodes placed along a single line providing one-dimensional spacing or along a plane providing two-dimensional spacing (e.g., laterally adjacent to each other). However, embodiments of the present disclosure may provide microelectrodes 502 that are laterally adjacent to each other and also vertically adjacent to each other and may be configured to receive ECM signals through a bottom electrode and a top electrode that are vertically adjacent to each other. In some embodiments of the present disclosure, the vertical spacing Vs between the microelectrodes 502 may provide greater resolution of the extracellular matrix (ECM) signal. In addition, a clear bipolar signal may be generated between the microelectrode 502 located at the top of the flexible tip portion 500 and the microelectrode 502 located at the bottom of the flexible tip portion 500.

[0196] As previously described, whether any electrode located on the flexible microelectrode 500 is in contact with tissue can be determined based on the difference between the bottom signal received by the microelectrode 502 located on the bottom of the flexible tip 500 and the top signal received by the microelectrode 502 located on the top of the flexible microelectrode 500. For example, if the bottom microelectrode 502 is in contact with tissue and the top microelectrode 502 is located in a blood pool, then the bottom signal is different from the top signal. If both the bottom and top microelectrodes 502 are located in the blood pool, then in some embodiments, the bottom signal and the top signal may be the same. This can be determined by, for example, referring to Figure 31 The electrode control of each microelectrode is determined.

[0197] like Figure 19DAs further shown, the microelectrode 502 can extend vertically from the surface of the underlying structure (e.g., the first outer arm 504). In some embodiments, the microelectrode 502 can have a thickness ranging from 0.1 to 1000 microns. In some embodiments, the microelectrode 502 can have a thickness of 0.5 microns. By raising the microelectrode 502 away from the surface of the underlying structure, the microelectrode 502 can more easily contact the tissue.

[0198] Figure 20 The various embodiments of the present disclosure are shown in Figure 19A The flexible tip end portion 500 is shown in an isometric side view, top view, and distal end view. The flexible tip end portion 500 includes a reference Figure 19A to Figure 19C In an example, the flexible tip 500 includes longitudinally extending arms 504, 506, 508, 510, an expanded head 512, a head 514, and a mounting portion 516. As shown, the various components forming the flexible tip 500 (e.g., the longitudinally extending arms 504, 506, 508, 510, the expanded head 512, the head 514, and the mounting portion 516) may include planar cross-sections. For example, the thickness of each component may be less than the lateral width of each component. Accordingly, the top surface of the flexible tip 500 and the bottom surface of the flexible tip 500 may be flat, which may prove advantageous when forming the microelectrodes 502, the conductive traces 518, and / or the contact pads 520 on the flexible tip 500. As described herein, the lower structure of the flexible tip 500 may be formed of a flexible metal, such as Nitinol, and / or a flexible printed circuit board on which the microelectrodes 502, the conductive traces 518, and / or the contact pads 520 may be placed.

[0199] Figure 21A top view of the lower structure of a flexible tip 540 of a high-density electrode mapping catheter according to various embodiments of the present disclosure is shown. In some embodiments, the flexible tip 540 may include four microelectrode-carrying arms, including a first outer arm 542, a second outer arm 548, a first inner arm 544, and a second inner arm 546. These arms are laterally separated from one another. The inner portion of the flexible tip 540 may include an expanded head 550, and the outer portion of the flexible tip 540 may include a head 552, which may be connected via a connector 554. In some embodiments, the expanded head 550 may include a transverse top 556. In some embodiments, the transverse width L1 of the transverse top 556 may range from 0.08 to 0.32 mm. In an example, the transverse width L1 of the top 556 may be approximately 0.16 mm. The expanded head 550 may additionally include a tapered tip arm 558 having a width L2 ranging from 0.10 to 0.45 mm. In an example, the width L2 of the tapered tip arm 558 is approximately 0.21 mm. In some embodiments, the arms forming the head 552 may have a width L3 ranging from 0.1 to 0.45 mm. In an example, the width L3 of the arms forming the head 552 may be approximately 0.21 mm. The connecting portion 554 may have a lateral width L4 ranging from 0.08 to 0.32 mm. In some embodiments, the connecting portion 554 may have a lateral width L4 of approximately 0.16 mm.

[0200] As previously described, the first lateral arm 542 and the second lateral arm 548 may include a lateral lower structure, and the first medial arm 544 and the second medial arm 546 may include a medial lower structure. In some embodiments, the lateral width L5 of the first and second medial arms 544 and 546 may be in the range of 0.10 to 1.0 mm. In some embodiments, the lateral width L5 of the first and second medial arms 544 and 546 may be approximately 0.51 mm. In some embodiments, the lateral width L6 of the first and second lateral arms 542 and 548 may be in the range of 0.10 to 1.0 mm. In some embodiments, the lateral width L6 of the first and second lateral arms 542 and 548 may be approximately 0.51 mm.

[0201] In some embodiments, first lateral transition arm 562 can connect first lateral arm 542 to mounting portion 560; first inboard transition arm 564 can connect first inboard arm 544 to mounting portion 560; second inboard transition arm 566 can connect second inboard transition arm 546 to the mounting portion; and second lateral transition arm 568 can connect second lateral arm 548 to mounting arm 560. In some embodiments, the width L7 of first and second lateral transition arms 562, 568 can be in the range of 0.10 to 1.0 mm. In some embodiments, the width L7 of first and second lateral transition arms 562, 568 can be approximately 0.51 mm.

[0202] In some embodiments, as previously described, the flexible tip portion 540 may include a mounting portion 560. In some embodiments, the longitudinal length L8 of the mounting portion 560 may be in the range of 5 to 20 mm. In some embodiments, the longitudinal length L8 of the mounting portion 560 may be approximately 11.1 mm. In some embodiments, the longitudinal length L9 of the medial and lateral transition arms may be in the range of 3 to 20 mm. In some embodiments, the longitudinal length L9 of the flexible tip portion including the transition arms may be approximately 9.1 mm. In some embodiments, the longitudinal length L9 of the medial and lateral arms may be approximately 11.1 mm. 10 In some embodiments, the longitudinal length L of the inner and outer side walls may be in the range of 8 to 50 mm. 10 In some embodiments, the longitudinal length L of the expansion head 550 and the head 552 is 11 In some embodiments, the longitudinal length L of the expansion head 550 and the head 552 is in the range of 3 to 20 mm. 11 It can be 9.8 mm.

[0203] In some embodiments, the lateral spacing L between the first lateral arm 544 and the second medial arm 546 is 12 In some embodiments, the lateral spacing L between the first inner arm 544 and the second inner arm 546 is in the range of 0.10 to 4 mm. 12 In some embodiments, the lateral spacing L between the first inner arm 544 and the first outer arm 542 and between the second inner arm 546 and the second outer arm 548 is approximately 4 mm. 13 In some embodiments, the lateral spacing L between 13 It can be about 4 mm.

[0204] Figure 22A top view of an alternative embodiment of the lower structure of the flexible tip portion 580 of the high-density electrode mapping catheter according to various embodiments of the present disclosure is shown. In some embodiments, the flexible tip portion 580 may include four microelectrode carrying arms, which include a first outer arm 582, a second outer arm 588, a first inner arm 584, and a second inner arm 586 that can be mounted to a mounting portion 596. The mounting portion 596, the inner and outer arms 582, 584, 586, 588, the expanded head 590, and the head 592 can be formed from a single piece of material. The inner portion of the flexible tip 580 may include the expanded head 592, and the outer portion of the flexible tip 580 may include the head 592, which may be connected by a connecting portion 594. In some embodiments, the expanded head 590 and the head 592 are larger than in Figure 21 In some embodiments, the width of the elements forming the expanded head 590 and the head 592 is less than that of the reference head 590. Figure 21 In an example, by reducing the width of the expanded head 590, head 592, or other portions of the flexible tip 580, the force required to deflect the expanded head 590, head 592, or other portions of the flexible tip 580 can be reduced. Accordingly, various portions of the flexible tip 580 can be made more atraumatic. For example, portions of the flexible tip 580 may deflect more easily upon contact with tissue due to the reduced deflection force.

[0205] Figures 23A to 23F Figure 1 shows isometric top and side views of the arms of the lower structure of a high-density electrode mapping catheter according to various embodiments of the present disclosure. Figure 23A As shown, the lower structure 610 can be formed of a flexible material in some embodiments. In an example, the flexible material can include Nitinol and can be approximately 160 microns thick, but the flexible material can be thicker or less than 160 microns. In some embodiments, as shown Figure 23B As shown, the lower structure 610 may be coated with a top dielectric material layer 612-1 and / or a bottom dielectric material layer 612-2. In an example, the dielectric material may include, for example, parylene, polyimide, epoxy, etc., as described above. However, the dielectric material may include other types of dielectrics. In some embodiments, the thickness of the dielectric layers 612-1 and 612-2 may range from 1.0 to 30 microns. In an example, the dielectric layers 612-1 and 612-2 may be approximately 10 microns thick, although the dielectric material may be thicker or thinner. In some embodiments, the dielectric material may electrically insulate the lower structure from conductive traces formed on top of the dielectric layer. In some embodiments, a connecting layer may be located between the dielectric material and the flexible material. In an example, the connecting layer may be sputtered chromium having a thickness of approximately 1000 angstroms, although the sputtered chromium thickness may be greater or less than 1000 angstroms.

[0206] In some embodiments, the dielectric layers 612-1, 612-2 may extend laterally outward relative to the lower structure 110 to form non-traumatic inner and / or outer edges. In an example, as previously described, the lower structure 610 may have a planar cross-section with a thickness less than the width of the lower structure 610. In some embodiments, due to the relatively thin thickness of the lower structure 610, the lateral edges of the lower structure 610 may be sharp. Figure 23C As shown, in order to provide atraumatic lateral edges (e.g., outer and / or inner edges) of the lower structure 610, the dielectric layers 612-1, 612-2 can extend laterally outward relative to the lower structure 610. The atraumatic edges can serve as a shield / cushion to prevent the lower structure 610 from contacting other materials (e.g., the inner diameter of an introducer sheath, tissue within the heart, etc.).

[0207] Figure 23C is Figure 23B A cross section of the coated lower structure 610 along line 23C-23C is shown in FIG. Figure 23C As shown, the first and second dielectric layers 612-1, 612-2 may include first and second outer extensions 614-1, 614-2, and the first and second dielectric layers 612-1, 612-2 may include first and second inner extensions 616-1, 616-2. In some embodiments, such as referring to Figure 19A As described above, the first and second outer extensions 614-1, 614-2 and / or the first and second inner extensions 616-1, 616-2 may be formed on each portion of the flexible tip of the high-density electrode mapping catheter. Figure 21 The flexible head end portion 540 shown and described, including the outer lower structure 622 of the first outer transition arm 562, the first outer arm 542, the head 552, the second outer arm 548 and the second outer transition arm 568, can have first and second outer extensions 614-1, 614-2 arranged along the outer edge 618, the outer edge 618 along the outer lower structure 622 ( Figure 21). In some embodiments, the first and second lateral extensions 614-1, 614-2 can be positioned along the lateral edge 618 of one or more of the first lateral transition arm 562, the first lateral arm 542, the head 552, the second lateral arm 548, and / or the second lateral transition arm 568. In some embodiments, the lateral lower structure 622 can have first and second lateral extensions 616-1, 616-2 positioned along the lateral edge 620 of the lateral lower structure 622. In some embodiments, the first and second lateral extensions 616-1, 616-2 can be positioned along the lateral edge 620 of one or more of the first lateral transition arm 562, the first lateral arm 542, the head 552, the second lateral arm 548, and / or the second lateral transition arm 568.

[0208] Further references Figure 21 In some embodiments, the medial lower structure 624 including the first medial transition arm 564, the first medial arm 544, the expanded head 550, the second medial arm 546, and the second medial transition arm 566 may have first and second lateral extensions 614-1, 614-2 positioned along a lateral edge 626 disposed along the medial lower structure 624 ( Figure 21 ). In some embodiments, the first and second lateral extensions 614-1, 614-2 can be positioned along the lateral edge 624 of one or more of the first medial transition arm 564, the first medial arm 626, the expanded head 550, the second medial arm 546, and / or the second medial transition arm 566. In some embodiments, the medial lower structure 624 can have first and second medial extensions 616-1, 616-2 positioned along the medial edge 628 of the medial lower structure 624. In some embodiments, the first and second medial extensions 616-1, 616-2 can be positioned along the medial edge 628 of one or more of the first medial transition arm 564, the first medial arm 544, the expanded head 550, the second medial arm 546, and / or the second medial transition arm 566.

[0209] like Figure 23DAs shown, one or more conductive traces 636-1, 636-2 and / or conductive pads 638 may be formed on the outer surfaces of dielectric materials 612-1, 612-2. In some embodiments, one or more conductive traces 636-1, 636-1 and / or conductive pads 638 may be formed on the outer surface of first dielectric layer 612-1 and / or the outer surface of second dielectric layer 612-2. In some embodiments, conductive traces 636-1, 636-1 and / or conductive pads 638 may be formed from a conductive material, such as copper. The copper may have a thickness of approximately 7 microns, however, the thickness of the copper may be greater or less than 7 microns. In some embodiments, a connecting layer may be included between conductive traces 636-1, 636-2 and dielectric materials 612-1, 612-2. In one example, the connecting layer may be sputtered chromium having a thickness of approximately 130 angstroms. However, the thickness of the connecting layer may be greater or less than 130 angstroms.

[0210] like Figure 23E As shown, the first dielectric layer 612-1 is coated with a first outer dielectric layer 640-1, and the second dielectric layer 612-2 is coated with a second outer dielectric layer 640-2. In some embodiments, the outer dielectric layers 640-1 and 640-2 can protect one or more conductive traces 636-1 and 636-2 and / or one or more conductive pads 638 and / or prevent one or more conductive traces 636-1 and 636-2 and / or one or more conductive pads 638 from contacting tissue. In some embodiments, exposed areas 642 (although not shown) can be created within the outer dielectric layers 640-1 and 640-2. In an example, the exposed areas 642 can be passages extending through the outer dielectric layer 640-1, allowing access to the conductive pads 638. In some embodiments, the outer dielectric layers 640-1, 640-2 may have a thickness of approximately 10 microns, however, the thickness of the cover layer may be greater or less than 10 microns. Figure 23F As shown, electrode 644 may be located on the outer surface of overlying dielectric layer 640-1. In an example, electrode 644 may be formed of a conductive material such as gold. The gold may be approximately 0.5 microns thick, however, the thickness of the gold may be greater or less than 0.5 microns. In some embodiments, a connecting layer may be located between conductive pad 638 and electrode 644. In an example, the connecting layer may include nickel. In some embodiments, the nickel may have a thickness of approximately 0.4 microns, however, the thickness of the nickel may be greater or less than 0.4 microns.

[0211] Figure 24AA top view of the lower structure of a flexible tip portion 660 of a high-density electrode mapping catheter including a plurality of electrodes 662-1, 662-2, 662-3, 662-4, hereinafter collectively referred to as electrodes 662, traces 664, and a mounting portion 666, according to various embodiments of the present disclosure is shown. As described herein, the flexible tip portion 660 may include a first lateral arm 668, a first medial arm 670, a second medial arm 672, and a second lateral arm 674. In some embodiments, the flexible tip portion 660 may include a first lateral transition arm 676, a first medial transition arm 678, a second medial transition arm 680, and a second lateral transition arm 682. The proximal ends of the transition arms may be connected to a mounting portion including a contact pad 684. As described in reference Figures 8A to 8C As described above, the conductive trace 664 can be connected to each electrode located on the lower structure of the flexible tip portion 660. The conductive trace 664 can extend from each electrode 662 downwardly along each outer arm 668, 674, inner arm 670, 672, outer transition arm 676, 682, inner transition arm 678, 680 proximally to the mounting portion 660. In some embodiments, as described above, Figure 19A As described above, the conductive trace 664 may terminate at the first or second row of contact pads 684-1, 684-2. In some embodiments, the detection trace may extend proximally from each contact pad in the first or second row of contact pads 684-1, 684-2. Figure 24A As described in detail above, the density of conductive traces 664 covering the lower structure of the flexible tip portion 660 increases in the proximal direction. For example, as shown, the proximal portions of the outboard mounting arms 668, 674 and the inboard mounting arms 678, 680; each of the outboard transition arms 676, 682 and the inboard transition arms 678, 680; and the mounting portion 666 may include conductive traces 664 covering a majority of their surfaces as shown.

[0212] like Figure 24B As shown, the junction between the proximal end of the second outer arm 674 and the second outer transition arm 682 may include a plurality of conductive traces 664 covering a majority of the second outer arm 674 and the second outer transition arm 682. In some embodiments, such as with reference to Figure 4DAs previously described, the traces may extend beneath each of the plurality of electrodes 662. In some embodiments, vias 688-1, 688-2, 688-3, and 688-4, hereinafter collectively referred to as vias 688, may be formed within the dielectric coating covering the lower structure of the flexible tip portion 660 and may provide electrical connections between each conductive trace 664 and each electrode 662. In some embodiments, each conductive trace 664 may be routed around each via 688. In an example, each conductive trace 664 may have routing bends 690-1, 690-2, 690-3, 690-4, 690-5, hereinafter collectively referred to as routing bends 690, located within a portion of the conductive trace 664 adjacent to each via 688. In an example, routing bends 690 may be formed toward the proximal ends of the lateral and medial arms, where the density of conductive traces 664 increases. For example, to route the conductive trace 664 around the passage 688, the trace 664 can be routed outward or inward around the passage 688 relative to the longitudinal axis of the flexible tip end 660. Figure 24B As shown, routing bends 690-1, 690-2, 690-3 can be included within trace 664. In some embodiments, as trace 664 can extend proximally along the underlying structure (e.g., second lateral arm 674), the routing bends 690-1, 690-2, 690-3 can become greater (e.g., bend further outward or inward).

[0213] Figure 24C The various embodiments of the present disclosure are shown in Figure 24A FIG. 6 is an enlarged top view of a portion 696 of the flexible tip portion 660 including first and second rows of contact pads 684-1, 684-2, shown in FIG. As shown, a plurality of traces 664 can extend along the outboard and inboard transition arms 676, 682, 678, 680 and the mounting portion 666 to a contact pad (e.g., contact pad 692). In some embodiments, the mounting portion 666 can include expanded contact pad portions 694-1, 694-2. In an example, the expanded contact pad portions 694-1, 694-2 can extend laterally from either side of the mounting portion 666 and can provide an area including an increased lateral width that can provide increased space for mounting the first and second rows of contact pads 684-1, 684-2.

[0214] Figure 25AA top view of the lower structure of a flexible tip portion 700 of a high-density electrode mapping catheter including a plurality of electrodes 702-1, 702-2, 702-3, 702-4 and rows of contact pads 704-1, 704-2, 704-3, 704-4, according to various embodiments of the present disclosure, is shown. The flexible tip portion 700 may include a first lateral arm 706, a second lateral arm 712, a first medial arm 708, and a second medial arm 710. In some embodiments, the flexible tip portion 700 may include a mounting portion 714 connected to the lateral arms 706 and 712 via a first lateral transition arm 716 and a second lateral transition arm 722. The mounting portion 714 may be connected to the first and second medial arms 708 and 710 via a first medial transition arm 718 and a second medial transition arm 720.

[0215] like Figure 25A As shown, a plurality of electrodes (eg, electrodes 702 - 1 , 702 - 2 , 702 - 3 , 702 - 4 ) may be positioned along the arms of the flexible tip portion 700 . Figure 25B 25A , according to various embodiments of the present disclosure. In some embodiments, portions of the lower structure forming the outer arms 706, 712 and / or the inner arms 708, 710 may include protrusions 726-1, 726-1, 726-3, 726-4, 726-5, hereinafter collectively referred to as protrusions 726. In some embodiments, the protrusions 726 may extend laterally from an area of ​​the lower structure including the electrode 702. As shown in FIG. Figure 24B As previously described, the trace extending proximally from each electrode 702 may have a path bend 690 ( Figure 24B In some embodiments, the route bend 690 may be located on the protruding portion 726 .

[0216] Figure 25C The various embodiments of the present disclosure are shown in Figure 25A, an enlarged top view of the mounting portion 714 of the flexible tip end portion is shown in FIG. As shown, the mounting portion 714 may include expanded contact pad portions 730-1, 730-2. In some embodiments, the expanded contact pad portions 730-1, 730-2 may increase the lateral width of the mounting portion 714 so that rows of contact pads 704-1, 704-2, 704-3, 704-4 may be located on the mounting portion 714 as described above. In some embodiments, each row of contact pads 704 may include a plurality of laterally spaced contact pads 732-1, 732-2, ..., 732-8. In some embodiments, each row of contact pads 704 may include a common ground 734. In some embodiments, each row of contact pads 704 may correspond to an electrode set 702 located on the lateral and medial arms. In an example, the first row of contact pads 704-1 may correspond to microelectrodes located on the first outer arm 706; the second row of contact pads 704-2 may correspond to microelectrodes located on the first inner arm 708; the third row of contact pads 704-3 may correspond to microelectrodes located on the second inner arm 710; and the fourth row of contact pads 704-4 may correspond to microelectrodes located on the second outer arm 712. In some embodiments, as shown, each row of contact pads 704 may include a ground pad 734, which may serve as a ground for the electrodes located on the corresponding arm of the flexible tip 700. In some embodiments, as shown, each row of contact pads 704 may be longitudinally spaced apart from each other. Although not shown, the opposite side of the mounting portion 714 may include additional rows of contact pads. For example, where electrodes are located on both the outer and inner lower structures, the contact pads may be located on either side of the mounting portion 714. Contact pads on a first side of mounting portion 714 may be electrically connected to electrodes on a first side of the outer and inner substructures, while contact pads on a second side of mounting portion 714 may be electrically connected to electrodes on a second side of the outer and inner substructures.

[0217] Figure 26 shows a similar embodiment according to various embodiments of the present disclosure Figure 19A 740 of a high-density electrode mapping catheter shown in FIG. 740 includes a plurality of wires 746 connected to connection pads located on a mounting portion 742. In an example, as described herein, the flexible tip may include a mounting portion 742 with a plurality of contact pads located on the mounting portion 742 (at Figure 26 In some embodiments, a wire (e.g., wire 746) may be connected to each contact pad, electrically connecting an electrode (e.g., electrode 748) on the flexible tip portion 740 and an associated conductive trace 750 to the wire 746.

[0218] Figure 27AA flexible cable segment 752 is shown according to various embodiments of the present disclosure. In some embodiments, a first flexible cable segment 754-1, a second flexible cable segment 754-2, and a third flexible cable segment 754-3, hereinafter collectively referred to as flexible cable 754, are shown. In an example, each flexible cable segment includes a plurality of conductive traces. For example, the first flexible cable segment 754-1 may include conductive traces 758-1, 758-2, ..., 758-8, hereinafter collectively referred to as conductive traces 758. In some embodiments, as further referenced Figure 27B As described above, a plurality of conductive traces 758 may be located on a polymer backing 766. Additionally, each flexible cable segment may include a ground trace 764 extending parallel to the conductive trace 758. In some embodiments, detection segments 756-1 and 756-2 may be located between the flexible cable segments 754. In an example, each detection segment 756-1 and 756-2 may include a plurality of detection traces 762-1, 762-2, ..., 762-8, hereinafter collectively referred to as detection traces 762, connected to each conductive trace 758. In some embodiments, each detection segment 756-1 and 756-2 may also include a ground detection trace 764 electrically connected to the ground trace 764. In some embodiments, the detection traces 762 and the ground detection trace 764 may have a wider lateral width than the conductive trace 758 to allow the traces of the detection segment 756 to be probed using an instrument. The ground detection trace 764 may include a via 768 that extends through the polymer backing 766 and electrically connects the ground detection trace 764 to the ground pad 772 ( Figure 27B ).

[0219] In some embodiments, such as Figure 27B As further shown in , the ground sense trace 764 may include a via electrically connecting it to the ground pad 772 . Figure 27B The various embodiments of the present disclosure are shown in Figure 27A FIG. 7 is a cross-sectional end view of a ground trace 760 of a flexible cable 752 shown in FIG. In some embodiments, the ground trace 760 may be formed of copper and may be located on top of a polymer backing 766. The ground trace 760 may have a thickness of approximately 10 microns, although the thickness of the ground trace 760 may be greater or less than 10 microns. In an example, the polymer backing 766 may be formed of polyimide. The polymer backing 766 may have a thickness of approximately 25 microns, although the thickness of the polymer backing 766 may be greater or less than 25 microns. In some embodiments, each flexible cable may have a ground trace 760 that provides signal noise reduction and improves the electrocardiogram signal received by the microelectrodes and passed through the flexible cable 752.

[0220] In some embodiments, the ground pad 772 may be located on the opposite side of the ground trace 760 on the polymer backing 766. The ground pad 772 may have a thickness of approximately 12 microns, however, the thickness of the ground pad 772 may be greater or less than 12 microns. In some embodiments, as shown in FIG. Figure 27A As described above, vias (not shown) may be formed within the polymer backing 766 and may electrically connect the ground trace 760 to the ground pad 772. In some embodiments, a first polymer layer 770 may be located on the top of the flexible circuit and a second polymer layer 774 may be located on the bottom of the flexible circuit to protect the traces (e.g., the ground trace 760) and / or the ground pad 772. The first polymer layer 770 may have a thickness of approximately 15 microns, however, the thickness of the first polymer layer 770 may be greater or less than 15 microns. The second polymer layer 774 may have a thickness of approximately 25 microns, however, the thickness of the second polymer layer 774 may be greater or less than 15 microns. In some embodiments, the first and second polymer layers may comprise polymers, such as a polymer selected from the group of dissipation factor-photo sensitive resist (DF-PSR) materials.

[0221] In some embodiments, as described herein, one or more flexible cables 752 may be electrically connected to microelectrodes located on the flexible tip of a high-density electrode mapping catheter. As shown, the flexible cable 752 may include eight detection traces 762 and a common ground. In some embodiments, five flexible cables may be attached to each side of the flexible tip of a high-density electrode mapping catheter to allow for 40 microelectrodes on each side of the flexible tip. This saves time and resources because a semi-automated process with separate welding of forty contacts on each side is provided. In an example, each flexible cable 752 may have a matching pattern on the contact pads located on the flexible tip. For example, the flexible cable 752 may be connected to a row of contact pads 704 ( Figure 25C )match.

[0222] Figure 28A flexible tip 780 of a high-density electrode mapping catheter is shown positioned within the distal end of a catheter shaft 782, according to various embodiments of the present disclosure. The flexible tip 780 of the high-density electrode mapping catheter may include features such as those discussed herein. As shown, a proximal portion of the flexible tip 780 is positioned within the distal end of the catheter shaft 782. Although not shown, as described herein, the mounting portion of the flexible tip 780 may be positioned within a lumen defined by the distal end of the catheter shaft 782. In some embodiments, a connector 784 may be positioned at the distal end of the catheter shaft 782 and may connect the flexible tip 780 to the distal end of the catheter shaft 782. As shown, a first lateral transition arm 786, a second lateral transition arm 792, a first medial transition arm 788, and a second medial transition arm 790 may extend distally from the connector 784 and the distal end of the catheter shaft 782. In some embodiments, and as shown, an adhesive 794 (eg, epoxy) may be located around the proximal end of the transition arm and the connector 784 to secure the flexible tip end 780 and the catheter shaft 782 .

[0223] Figure 29 A high-density electrode mapping catheter 800 according to various embodiments of the present disclosure is shown. In some embodiments, the high-density electrode mapping catheter 800 may include a flexible tip 802 located at the distal end of a catheter shaft 804. In some embodiments, the catheter shaft 804 may include one or more ring electrodes 806-1, 806-2, as described herein. In some embodiments, the flexible tip 802 may include electrodes located on both sides of the flexible tip 802. In some embodiments, a cable-shaft coupler may be located at the proximal end of the catheter shaft 804 and may connect a first sensing cable 808-1 and a second sensing cable 808-2 to the catheter shaft. In some embodiments, the first sensing cable 808-1 may include electrical connections for electrodes located on a first side of the flexible tip 802, and the second sensing cable 808-2 may include electrical connections for electrodes located on a second side of the flexible tip 802. In some embodiments, the first sensing cable 808-1 may include electrical connections for electrodes located on the flexible tip 802, and the second sensing cable 808-2 may include electrical connections for the ring electrodes 806-1, 806-2. In some embodiments, the proximal ends of the first and second sensing cables 808 - 1 , 808 - 2 may include first and second connectors 810 - 1 , 810 - 2 that may be connected to a computer configured to analyze signals received from electrodes located on the flexible tip 802 .

[0224] Figure 30Another embodiment of a high-density electrode mapping catheter 820 according to various embodiments of the present disclosure is shown. In some embodiments, the high-density electrode mapping catheter 820 may include a flexible tip portion 822 located at the distal end of a catheter shaft 824. Figure 29 In contrast, the catheter shaft 824 does not include a ring electrode. In some embodiments, the flexible tip 822 may include electrodes on both sides of the flexible tip 822. In some embodiments, a cable-shaft coupler 826 may be located at the proximal end of the catheter shaft 824 and may couple a first sensing cable 828-1 and a second sensing cable 828-2 to the catheter shaft 824. In some embodiments, the first sensing cable 828-1 may include electrical connections for electrodes located on a first side of the flexible tip 822, and the second sensing cable 828-2 may include electrical connections for electrodes located on a second side of the flexible tip 822. In some embodiments, the proximal ends of the first and second sensing cables 828-1, 828-2 may include first and second connectors 820-1, 820-2 that may be connected to a computer configured to analyze signals received from the electrodes located on the flexible tip 822.

[0225] Figure 31 A schematic diagram and block diagram of a medical system 840 according to an embodiment of the present disclosure are shown. The system 840 is shown to include a main electrical control unit 842 (e.g., a processor) having various input / output mechanisms 844, a display 846, an optional image database 848, an electrocardiogram (ECG) monitor 850, a positioning system such as a medical positioning system 852, an elongated medical device 854 enabled by the medical positioning system, a patient reference sensor 856, a magnetic position sensor 858, an electrode 860 (e.g., a position sensing electrode), and a microelectrode 862 configured to sense electrical signals generated by the heart. For simplicity, one magnetic position sensor 858, one electrode 860, and one microelectrode 862 are shown, however, more than one magnetic position sensor 858, more than one electrode 860, and / or more than one microelectrode 862 may be included in the system 300.

[0226] The input / output mechanism 844 may include conventional devices for interacting with a computer-based control unit including, for example, one or more keyboards, mice, tablets, foot pedals, switches, and / or the like. The display 846 may also include conventional devices such as a computer monitor.

[0227] The system 840 may optionally include an image database 848 to store image information about the patient's body. The image information may include, for example, a region of interest surrounding the intended site of the medical device 854 and / or multiple regions of interest along a navigation path expected to be traversed by the medical device 854. The data in the image database 848 may include known image types, including (1) one or more two-dimensional still images acquired at corresponding, separate times in the past; (2) multiple related two-dimensional images obtained in real time from an image acquisition device (e.g., fluoroscopic images obtained from an x-ray imaging device), where the image database serves as a buffer (live fluoroscopic images); and / or (3) a sequence of related two-dimensional images defining a cine-loop, where each image in the sequence has at least one ECG timing parameter associated therewith sufficient to allow the sequence to be replayed based on the real-time ECG signal obtained from the ECG monitor 314. It should be understood that the foregoing embodiments are merely illustrative and not inherently limiting. For example, the image database may also include three-dimensional image data. It should also be understood that the image may be obtained by any imaging modality now known or later developed (eg, X-ray, ultrasound, computed tomography, magnetic resonance imaging, etc.).

[0228] The ECG monitor 850 is configured to continuously detect electrical timing signals from the heart organ using a plurality of microelectrodes 862. The timing signals are typically responsive to specific phases of the cardiac cycle. Typically, the ECG signal(s) may be used by the control unit 842 for ECG synchronization playback of previously captured image sequences (cine loops) stored in the database 848. Both the ECG monitor 850 and the ECG electrodes may comprise conventional components. In some embodiments, as described with reference to FIG. Figure 19D As described above, the main controller 842 may include a computing device, which may include hardware and / or a combination of hardware and programming configured to determine the difference in signals received by the microelectrodes. For example, the main controller 842 may include a non-transitory computer-readable medium storing instructions, which are executed by a processor, communicating with the main controller 842 to determine the difference in signals received from the microelectrodes. The medical positioning system 852 is configured to locally position the system and thereby determine position (location) data relative to one or more magnetic position sensors 858 and / or electrodes 860 and output corresponding position readings.

[0229] Figure 32 A control block diagram of a method 870 for determining the degree of contact between a first electrode and tissue according to various embodiments of the present disclosure is shown. In some embodiments, as described above, for example, with reference to Figure 19D, the method 870 may include receiving a first electrical signal from a first electrode located on a first side of the head end of the medical device in method control block 872. The method 870 may also include receiving a second electrical signal from a second electrode located on a second side of the head end of the medical device in method control block 874. As previously described, the first electrode and the second electrode may be vertically adjacent to each other. For example, as shown in FIG. Figure 19D As shown and described, the first electrode may be located directly beneath the second electrode.

[0230] In some embodiments, method 870 may include, at method control block 876, determining a degree of contact between the first electrode and the tissue based on a comparison between the first electrical signal and the second electrical signal. In an example, when the first electrode is placed against the tissue, the second electrode may be located on an opposite side of the medical device and within the blood pool. As a result, different electrical signals (e.g., voltages) may be received from the first electrode and the second electrode. Accordingly, in some embodiments, the comparison between the first electrical signal and the second electrical signal may include comparing a first voltage associated with the first electrical signal and a second voltage associated with the second electrical signal.

[0231] In an example, cardiac tissue can generate a voltage when it depolarizes. This voltage can propagate through the cardiac muscle and also through the blood pool and can be obtained by the first electrode and the second electrode. If one of the electrodes (e.g., the first electrode) is in contact with the tissue, that voltage will be different from the voltage obtained by the electrode (e.g., the second electrode) located in the blood pool. When the first electrode is in contact with the tissue and the second electrode is located in the blood pool, the difference between the first electrical signal associated with the first electrode and the second electrical signal associated with the second electrode will be greater. When both the first electrode and the second electrode are located in the blood pool, the difference between the first electrical signal associated with the first electrode and the second electrical signal associated with the second electrode will be smaller.

[0232] Contact between a medical device (e.g., a first electrode) and tissue can be determined based on a difference in electrical signals (e.g., voltages). For example, the method 870 may include determining that the first electrode is not in contact with tissue when a first voltage associated with the first electrical signal and a second voltage associated with the second electrical signal are the same. For example, when the voltages associated with the first electrode and the second electrode are the same, this indicates that the first electrode and the second electrode are located within the blood pool and are not in contact with tissue. In some embodiments, the method may include determining that the first electrode is not in contact with tissue when the difference between the first voltage associated with the first electrical signal and the second voltage associated with the second electrical signal is less than a threshold voltage (e.g., the voltages are almost the same). For example, due to electrical interference in the blood pool, the voltages associated with each of the first and second electrodes may not be exactly the same.

[0233] Alternatively, in some embodiments, the method 879 may include determining that the first electrode is in contact with tissue when the first electrode associated with the first electrical signal and the second electrode associated with the second electrical signal are different. In an example, the method 879 may include determining that the first electrode is in contact with tissue when the difference between the first electrode associated with the first electrical signal and the second electrode associated with the second electrical signal is greater than a threshold value. For example, the method 879 may include determining that the first electrode is in contact with tissue when a first voltage associated with the first electrical signal is greater than a second voltage associated with the second electrical signal (e.g., greater than a defined threshold value). As described, when the first electrode is positioned against tissue and the second electrode is located within a blood pool, the first electrical signal associated with the first electrode may be greater than the second electrical signal.

[0234] In some embodiments, the method 870 may include determining that the degree of contact between the first electrode and the tissue is increasing based on an increase in a first voltage associated with the first electrical signal relative to a second voltage associated with the second electrical signal. For example, if the first voltage associated with the first electrical signal increases at a rate greater than the second voltage associated with the second electrical signal and / or increases while the second voltage remains constant, then the degree of contact between the first electrode and the tissue may be determined to be increasing. In some embodiments, ensuring that sufficient contact exists between the medical device and the tissue is advantageous when diagnostic information is collected by a medical device (e.g., an electrode) and / or therapeutic energy is transmitted from a medical device (e.g., an electrode) to tissue. Alternatively, the method 870 may include determining that the degree of contact between the first electrode and the tissue is decreasing based on a decrease in the first voltage associated with the first electrical signal relative to the second voltage associated with the second electrical signal.

[0235] In some embodiments, the first and / or second electrode may be configured to be driven by an electric current (e.g., a high-frequency current). In an example, the first and / or second electrode may be driven by an electric current and the electric current may induce a voltage (e.g., a high-frequency voltage). For example, a voltage may be induced in cardiac tissue and / or a blood pool. Accordingly, the induced voltage generated by one or more electrodes other than the heart may be received by one or more electrodes on the medical device. The induced voltage (e.g., impedance) associated with the electrical signal received from one of the electrodes may be measured. The electrical signal may change depending on whether the electrode receiving the electrical signal is located in the blood pool or in contact with the tissue. In an example, if one of the electrodes is placed against the tissue and one of the electrodes is located in the blood pool, the induced voltage measured by the electrical signal received from the first electrode and the second electrode may be different, but may be similar if both electrodes are located in the blood pool.

[0236] In some embodiments, one or both of the first and second electrodes can be driven with an electric current, and one or more other electrodes located on the medical device or an electrode located on a skin patch can receive the induced voltage. In some embodiments, a current can be induced in the first electrode, and the induced voltage can be received by the second electrode. The magnitude of the induced voltage can be affected depending on whether the second electrode is located in the blood pool or in contact with cardiac tissue. Similarly, a current can be induced in the second electrode and the induced voltage can be received by the first electrode. The magnitude of the induced voltage can be affected depending on whether the first electrode is located in the blood pool or in contact with cardiac tissue. In some embodiments, a current can be induced in another electrode located on the medical device and the induced voltage can be received by one or both of the first and second electrodes. As described herein, the induced voltage associated with the electrical signal received by the first and second electrodes can be changed depending on whether one or more of the first and second electrodes are located in the blood pool or placed against cardiac tissue.

[0237] Figure 33 A control block flow diagram of a method 880 for determining cardiac activation associated with endocardial tissue according to various embodiments of the present disclosure is shown. Figure 33 As described above, method 880 may include receiving a first electrical signal from a first electrode located on a first side of the head portion of the medical device in method control block 882. In some embodiments, method 880 may include receiving a second electrical signal from a second electrode located on a second side of the head portion of the medical device in method control block 884. As previously described, the first electrode and the second electrode may be similar to the reference electrode. Figure 19D The approaches shown and described are positioned vertically adjacent to each other.

[0238] In some embodiments, method 880 may include determining a characteristic associated with cardiac activation in method control block 886, wherein the cardiac activation is located in a direction perpendicular to the surface of the endocardial tissue. In an example, because the first electrode and the second electrode are vertically adjacent to each other, as the cardiac activation propagates through the endocardial tissue, the electrical activation signal may be received by the first electrode positioned against the tissue and then by the second electrode vertically adjacent to the first electrode. For example, because the electrical activation signal propagates toward the surface of the endocardial tissue on which the first electrode is positioned, the electrical activation signal may propagate in a direction perpendicular to the surface of the endocardial tissue toward the first electrode. Since the electrical activation signal reaches the surface of the endocardial tissue on which the first electrode is positioned, the first electrical signal may be received by the first electrode. The electrical activation signal may then propagate through a portion of the blood pool and be received by the second electrode positioned vertically adjacent to the first electrode. Because the two electrodes are positioned vertically adjacent to each other, this may allow for better measurement of the electrical activation signal.

[0239] In some embodiments, features associated with cardiac activation may include the direction of cardiac activation. For example, a component of a directional vector of cardiac activation may be determined to be perpendicular to the surface of the endocardial tissue. In some embodiments, it is common for cardiac activation to be oriented perpendicular to the surface of the endocardial tissue. For example, in thick ventricular tissue, cardiac activation may be oriented perpendicular to the surface of the endocardial tissue.

[0240] In some embodiments, method 880 may include filtering noise from the first electrical signal based on the second electrical signal. For example, if the first electrode is positioned against the surface of endocardial tissue, ambient noise may negatively impact the first electrical signal associated with the first electrode. Ambient noise may be caused by stray electrical signals flowing through the blood pool in some embodiments. Accordingly, the second electrode positioned within the blood pool may receive any stray electrical signals flowing through the blood pool, which may be reflected in the second electrical signal associated with the second electrode. In some embodiments, the second electrical signal may be used to filter the stray electrical signals from the first electrical signal.

[0241] In some embodiments, method 870 and method 880 may be performed by, for example, referring to Figure 31 In some embodiments, the method control block diagrams (e.g., control block diagrams 872, 874, 876, 882, 884, 886) may represent computer-implemented instructions stored on a non-transitory computer-readable medium (CRM), which may be executed by a processor in communication with a computer to perform a specific function (e.g., receiving a first electrical signal from a first electrode located on a first side of a head portion of a medical device).

[0242] Embodiments of various devices, systems, and / or methods are described herein. A number of specific details are set forth to provide a thorough understanding of the overall structure, function, manufacture, and use of the various embodiments described in the specification and shown in the accompanying drawings. However, it will be understood by those skilled in the art that the various embodiments can be implemented without these specific details. In other cases, known operations, parts, and elements are not described in detail in order to obscure the various embodiments described in the specification. It will be understood by those of ordinary skill in the art that the various embodiments described and shown herein are non-limiting examples, and therefore it will be understood that the specific structural and functional details disclosed herein may be representative and will not necessarily limit the scope of the various embodiments, and the scope of the invention is limited only by the appended claims.

[0243] References throughout this specification to "various embodiments," "some embodiments," "an embodiment," or "an embodiment" mean that the particular feature, structure, or characteristic described in connection with the embodiment(s) is included in at least one embodiment. Thus, the appearances of the phrases "in various embodiments," "in some embodiments," "in one embodiment," or "in an embodiment," etc., in various places throughout this specification do not necessarily refer to identical embodiments. Furthermore, particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Thus, particular features, structures, or characteristics shown or described in connection with one embodiment may be combined, in whole or in part, with features, structures, or characteristics of one or more other embodiments without restriction, as long as such combination is not illogical or non-functional.

[0244] It should be understood that the terms "proximal" and "distal" can be used throughout this specification with reference to a clinician manipulating an end of an instrument for treating a patient. The term "proximal" refers to the portion of the instrument closest to the clinician, while the term "distal" refers to the portion farthest from the clinician. It should also be understood that for simplicity and clarity, spatial terms such as "vertical," "horizontal," "upper," and "lower" can be used herein with respect to the illustrated embodiments. However, medical instruments can be used in many directions and positions, and these terms are not intended to be limiting and absolute.

[0245] Although at least one embodiment of a high-density electrode mapping catheter has been described above with a certain degree of particularity, a person skilled in the art may make various changes to the disclosed embodiments without departing from the spirit or scope of the invention. All directional references (e.g., up, down, upward, downward, left, right, leftward, rightward, top, bottom, above, below, vertical, horizontal, clockwise, and counterclockwise) are used only for identification purposes to help the reader understand the invention and do not impose any restrictions in particular on the position, direction, or use of the device. Connection references (e.g., fixing, attaching, joining, connecting, etc.) should be interpreted broadly and may include intermediate members between the connection of elements and relative movement between elements. Thus, connection references do not necessarily mean that two elements are directly connected to each other and are in a fixed relationship. It is intended that all matters contained in the above description or shown in the accompanying drawings should be interpreted as illustrative only and not restrictive. Changes in detail or structure may be made without departing from the spirit of the present disclosure as defined in the appended claims.

[0246] Any patent, publication, or other public material deemed to be incorporated herein by reference in whole or in part is incorporated herein only to the extent that it does not conflict with existing definitions, statements, or other public material set forth in this disclosure. Thus, to the extent necessary, the disclosure explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material or portion thereof deemed to be incorporated herein by reference that conflicts with existing definitions, statements, or other public material set forth herein is incorporated only to the extent that there is no conflict between the included material and existing public material.

Claims

1. An integrated mapping electrode catheter, comprising: a catheter shaft comprising a proximal end and a distal end, the catheter shaft defining a catheter shaft longitudinal axis; a flexible tip portion positioned proximate a distal end of the catheter shaft and adapted to conform to cardiac tissue, the flexible tip portion comprising a flexible frame formed from a planar base defining a top surface and a bottom surface, the bottom surface being parallel to the top surface; and a first microelectrode array and a second microelectrode array, the first microelectrode array being patterned onto the top surface of the planar substrate of the flexible frame and the second microelectrode array being patterned onto the bottom surface of the planar substrate of the flexible frame, wherein the first microelectrode array is parallel to the second microelectrode array and at least one of the first microelectrode array or at least one of the second microelectrode array is configured to contact cardiac tissue to sense electrical signals; At least one of the first microelectrode arrays is configured to sense a first electrical signal, and at least one of the second microelectrode arrays is configured to sense a second electrical signal, wherein the degree of contact between the cardiac tissue and the flexible head end is determined by an electronic controller based on an analysis of the first electrical signal and the second electrical signal. 2 . The integrated mapping electrode catheter of claim 1 , wherein the flexible tip portion comprises a plurality of longitudinally extending arms.

3. The integrated mapping electrode catheter according to claim 2, wherein: The plurality of longitudinally extending arms includes a first medial arm, a second medial arm, a first lateral arm, and a second lateral arm; and The first inner arm, the second inner arm, the first outer arm and the second outer arm are parallel to each other. 4 . The integrated mapping electrode catheter according to claim 3 , wherein the distal end of the first inner arm is connected to the first outer arm, and the distal end of the second inner arm is connected to the second outer arm.

5. The integrated mapping electrode catheter according to claim 4, wherein: The first medial arm, the second medial arm, the first lateral arm, and the second lateral arm include a proximal end; and The proximal end is disposed within the distal end of the catheter shaft.

6. The integrated mapping electrode catheter according to claim 1 further comprises a plurality of conductive traces located on the flexible frame, each of the plurality of conductive traces being electrically connected to a corresponding one of the first microelectrode array and the second microelectrode array. 7 . The integrated mapping electrode catheter of claim 6 , further comprising a dielectric material located between each of the plurality of conductive traces and the flexible frame.

8. The integrated mapping electrode catheter of claim 7, wherein the dielectric material covers an outwardly facing surface of each of the plurality of conductive traces.

9. The integrated mapping electrode catheter of claim 1, wherein each of the first microelectrode array and the second microelectrode array comprises a row of longitudinally aligned microelectrodes aligned parallel to the longitudinal axis of the catheter shaft.

10. The integrated mapping electrode catheter of claim 6, wherein each of the plurality of conductive traces is aligned parallel to the catheter shaft longitudinal axis.

11. An integrated mapping electrode catheter, comprising: a catheter shaft comprising a proximal end and a distal end, the catheter shaft defining a catheter shaft longitudinal axis; a flexible tip portion positioned proximate a distal end of the catheter shaft and adapted to conform to cardiac tissue, wherein the flexible tip portion comprises an inner lower structure and an outer lower structure, the inner lower structure and the outer lower structure having a top surface and a bottom surface, respectively; and a first microelectrode array and a second microelectrode array, the first microelectrode array being patterned to the top surfaces of the medial and lateral substructures and the second microelectrode array being patterned to the bottom surfaces of the medial and lateral substructures, wherein the first microelectrode array is parallel to the second microelectrode array and at least one of the first microelectrode array or at least one of the second microelectrode arrays is configured to contact cardiac tissue to sense electrical signals; At least one of the first microelectrode arrays is configured to sense a first electrical signal, and at least one of the second microelectrode arrays is configured to sense a second electrical signal, wherein the degree of contact between the cardiac tissue and the flexible head end is determined by an electronic controller based on an analysis of the first electrical signal and the second electrical signal.

12. The integrated mapping electrode catheter of claim 11, wherein the inner substructure and the outer substructure comprise atraumatic edges extending around boundaries of the inner substructure and the outer substructure.

13. The integrated mapping electrode catheter according to claim 11 further includes a mounting portion connected to the inner lower structure and the outer lower structure, wherein the mounting portion includes a plurality of contact pads, and the plurality of contact pads are electrically connected to the first microelectrode array and the second microelectrode array through a plurality of conductive traces.

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