Separable sheath

Abstract

A separable sheath for an implantable medical device may include a shell having an outer diameter and an inner diameter. A lumen may be defined by an inner diameter and extend from a proximal end to a distal end of the shell. The electrode may be located at a distal end of the sheath. A signal line may be disposed within the housing and electrically coupled to the electrode. The guide rail may be configured to shield the signal line from a cutting path of the sheath separator. In some examples, the sheath may also include a second rail. For example, the signal line may be located between the first rail and the second rail along the length of the sheath. The cutting path may be located between the first rail and the second rail on a side of the sheath radially opposite the signal line.

Description

[0001] This application is a divisional application of the invention application with application date of March 14, 2020, application number 202080017642.6, and invention name “Detachable Sheath”. Technical Field

[0002] The present disclosure relates to a detachable sheath for navigating placement of an implantable device into a patient's body. Background Art

[0003] Cardiac rhythm management systems can be used to electrically stimulate a patient's heart to treat a variety of arrhythmias. The current standard of care is right ventricular pacing via myocardial stimulation. In this technique, pacemaker leads are placed at the right ventricular apex and atrioventricular node, coronary sinus, or left ventricle, and the pacemaker sends electrical pulses to these areas of the heart. While effective, this technique can result in abnormal sequences of electrical activation that can lead to mechanical ventricular dyssynchrony, increasing the risk of heart failure, atrial fibrillation, and overall mortality.

[0004] An alternative approach has been proposed in which an electrode lead is placed in the bundle of His, located in the septum of the right atrium or also in the atrial septum, under the valve from the right ventricle. As part of the heart's electrical conduction system, the bundle of His transmits electrical impulses from the atrioventricular node to the ventricles. As the electrical impulses that regulate the heartbeat are conducted from the right atrium to the left and right ventricles through the bundle of His, the leads placed in or near the bundle of His will enable the entire electrical conduction system to be paced in a physiologically natural manner. Pacing the ventricles in this way can well simulate normal atrioventricular conduction and can greatly reduce or eliminate the risks of traditional CRT pacing.

[0005] Although the improved outcomes obtainable with His pacing are recognized, in practice, His pacing is difficult to achieve because the His bundle is very small and difficult to locate and access with available equipment. The nominal length of the His bundle is approximately 5 mm and the nominal width is approximately 2 mm. The electrical signal it generates is only a small fraction of the electrical signal generated by the ventricles. Due to its small size and weak electrical signal, the His bundle is extremely difficult to find using conventional pacing leads. In addition, once the His bundle is located, it is difficult to maintain the position of the lead while it is secured to the heart tissue. The difficulties involved in locating the His bundle and securing a pacing lead to it are reflected in the time it takes to implant the leads of an electrical stimulation device, such as a pacemaker. In a typical case, implantation of a biventricular lead can be accomplished in less than 1 minute. In contrast, placement of a single lead for His pacing may take 30 minutes or more, often without success. In these cases, physicians typically revert to conventional lead placement.

[0006] Once the lead is placed and secured to the tissue, the sheath can be withdrawn from the patient and removed from the lead. To remove the sheath from the lead, the blade can cut the sheath longitudinally. The blade can cut the sheath from the proximal end to the distal end. The cutting is typically performed as the sheath is withdrawn from the body. Typically, the blade's travel is unpredictable or irregular. In some cases, the blade can cut through various wires or liners within the sheath. As a result, the electrical connection can degrade or be severed. In other cases, the wires or liners may break off the sheath, creating fragments. In some instances, the fragments may enter the patient's body, for example, the fragments may fall into the incision through which the sheath is inserted into the body. Due to manufacturing limitations, the internal components of the sheath are not always sterile.

[0007] Therefore, there is a need for an improved device for delivering and implanting electrode leads to reduce the formation of debris generated when the sheath is separated from the lead. The foregoing discussion is intended only to illustrate the art and should not be construed as a denial of the scope of the claims. Summary of the invention

[0008] The present disclosure relates to a detachable sheath for an implantable medical device that treats or diagnoses arrhythmias by, for example, a steerable sheath for guiding and delivering an implantable lead to a target location in a patient's body. In some examples, the sheath may include one or more electrodes for identifying a fixation site along tissue. Typically, the tip portion of the lead may include an anchor to secure the lead to tissue (e.g., a beating heart wall). The sheath may include various separation devices, as further described herein, for removing the sheath from the lead when the lead is secured to tissue. The lead may be used for cardiac resynchronization therapy (CRT).

[0009] In one example, a detachable sheath for an implantable medical device may include a sheath having an outer diameter and an inner diameter. A cavity may be defined by the inner diameter and may extend from a proximal end of the sheath to a distal end. An electrode may be located at the distal end of the sheath. A signal line may be disposed within the sheath and electrically coupled to the electrode. The guide rail may be configured to shield the signal line from a cutting path of the sheath separator.

[0010] In some examples, the sheath may also include a second rail. For example, the rail may be a first rail, and the signal line may be located between the first rail and the second rail along the length of the sheath. The cutting path may be located between the first rail and the second rail, on the side of the sheath radially opposite to the signal line. At the proximal end of the sheath, the first rail may be located at a radial offset greater than 270 degrees from the second rail. At the distal end of the sheath, the radial offset of the first rail from the second rail is less than 90 degrees. In one example, the cutting zone may be defined between the first rail and the second rail on the side of the sheath radially opposite to the signal line. The cutting area at the proximal end of the shell may be larger than the cutting area at the distal end of the sheath. In one example, the rail may be exposed from the shell at the proximal end.

[0011] In various examples, the guide rail can be constructed of a cut-resistant material. For example, the guide rail is made of stainless steel. The guide rail can be configured to reduce debris formation due to contact with the sheath separator. For example, the guide rail can include a solid cross-section.

[0012] In some examples, the signal line can be located on a curved plane along a cross-section of the sheath. In various examples, the sheath can include a sheath strip extending from a proximal end to a distal end. In one example, the sheath strip can be made of a softer material than the material of the sheath. In some examples, the sheath can include two sheath strips extending from a proximal end to a distal end. In one example, the sheath strip can be more resistant to cutting than the material of the sheath.

[0013] In one example, the radial position of the signal line and the guide rail can remain constant along the length of the sheath. In some examples, the detachable sheath can include a pull wire disposed within the shell. The guide rail can also be configured to shield the pull wire from the cutting path. In one example, the detachable sheath can include a lead wire disposed in the sheath cavity.

[0014] In some examples, the detachable sheath may include a shell having an outer diameter and an inner diameter. The cavity may be defined by the inner diameter and extend from the proximal end of the shell to the distal end. The electrode may be located at the distal end of the shell. The signal line may be disposed within the shell and electrically connected to the electrode. The detachable sheath may include a first rail and a second rail, each of the first rail and the second rail being configured to shield the signal line from a cutting path of the sheath separator. The signal line may be located between the first rail and the second rail along the length of the sheath. The cutting path may be located between the first rail and the second rail, on a side of the sheath radially opposite to the signal line.

[0015] In another example, a method of making a detachable sheath may include placing a lead liner on a cavity mandrel and placing a signal line liner on the signal line mandrel. The first guide rail mandrel and the second guide rail mandrel may be positioned along the outer diameter of the lead liner. The signal line liner may be located between the first guide rail mandrel and the second guide rail mandrel along the length of the sheath. A shell may be applied to the signal line liner and the first and second guide rail mandrels. Each of the cavity mandrel, the signal line mandrel, and the first and second guide rail mandrels may be removed after the shell is applied. After removing the cavity mandrel, the signal line mandrel, and the first and second guide rail mandrels, the signal line may be inserted into the signal line liner cavity, the first guide rail may be inserted into the first guide rail cavity, and the second guide rail may be inserted into the second guide rail cavity. The signal line may be electrically connected to an electrode located at the distal end of the shell.

[0016] In one example, the method may include placing a braid around the signal line liner and the first and second guide rails before applying the sheath. The sheath may be extruded onto the braid. In another example, applying the sheath may include placing an extruded profile on the signal line liner, the first and second guide rails, and the lead liner. In one example, the extruded profile may be heated to melt the profile around the signal line liner, the first and second guide rails, and the lead liner. In another example, applying the sheath may include applying a sheath including a sheath strip. The sheath strip may include a different material from the sheath. In some examples, placing the signal line cavity may include placing the signal line cavity along a curved plane of the sheath. In one example, inserting the first and second rails may include inserting the first and second rails constructed of solid material to reduce debris formation. For example, the first and second rail cavities may be unlined and the first and second rails may be uncoated.

[0017] The foregoing and other aspects, features, details, utilities, and advantages of the present disclosure will become apparent from a reading of the following description and claims, and from a reading of the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Examples of catheter delivery systems are described.

[0019] Figure 2 An example of a detachable sheath having a lead extending through a lumen of the sheath is shown.

[0020] Figure 3 A cross section of a sheath including a lead inserted into a lumen of the sheath is depicted.

[0021] Figure 4 An isometric view of an example of a first side of a portion of a sheath is depicted, showing a majority of the shell removed.

[0022] Figure 5 Depicted Figure 4 An isometric view of an example of an opposite second side of the sheath.

[0023] Figure 6 Shows Figure 4 Example of a first cross section of a jacket.

[0024] Figure 7 Shows Figure 4 Example of a second cross section of a jacket.

[0025] Figure 8 Shows Figure 4 Example of a third cross section of a jacket.

[0026] Fig. 9 Describes the Figure 4 Detailed view of an example of a portion of the sheath between the second and third cross-sections.

[0027] Fig.10 and Fig.11 An example of a cutting zone between a first rail and a second rail is shown.

[0028] Fig.12 An example of a sheath strip positioned along a cutting area is depicted.

[0029] Fig.13 An example of a cross section of a sheath including a pull wire, a first rail, and a second rail is shown.

[0030] Fig.14 An example of a sheath including a diverter for directing a blade around one or more electrodes of the sheath is depicted.

[0031] Fig.15 , Fig.16 and Fig.17 An example of a technique for making a detachable sheath is depicted.

[0032] Fig.18 An example of a sheath is shown in a partially assembled state.

[0033] Fig.19 Depicted with Fig.18 Example of the tip portion of the sheath connection.

[0034] Fig. 20 An example of a sheath comprising a plurality of sheath strips is shown. DETAILED DESCRIPTION

[0035] Several embodiments of catheter delivery systems are disclosed herein, such as a catheter delivery system including a steerable sheath for guiding and delivering an implantable lead. The sheath may include one or more electrodes for identifying a fixation site along the tissue. Typically, the tip portion of the lead may include an anchor to secure the lead to the tissue (e.g., a beating heart wall). As described herein, the sheath may include various separation devices for removing the sheath from the lead when the lead is secured to the tissue. The details of various embodiments of the present disclosure are described below with specific reference to the accompanying drawings.

[0036] Figure 1 A catheter delivery system 100 is shown, which includes a handle 104, a sheath 102 operably coupled to the handle 104, and a guide wire 106 disposed in a lumen of the sheath 102. Figure 1 In the example shown, lead 106 can be navigated by sheath 102 through subclavian vein 122 and superior vena cava into right atrium 112 of heart 110. In one example, lead 106 can be used to deliver cardiac resynchronization therapy (CRT) to heart 110. For example, lead 106 can be a cardiac pacing lead. A distal end 127 of lead 106 can be secured to tissue, and a proximal end of lead 106 can be operably coupled to a cardiac resynchronization device (CRD). For example, the distal end of lead 106 can include an anchor 108, such as a helical fixation screw, a fixation barb, or other fixation device. In some examples, electrodes 128A, 128B can contact tissue, or in other examples, electrodes 128A and 128B can detect near-field electrophysiological signals from heart 110 to detect the position of distal end 127 of sheath 102 using electrophysiological signals (e.g., electrograms or electrocardiogram signals). Although Figure 1 The example of FIG. 1 describes a catheter delivery system 100 for placement of a CRT lead, but in other examples it should be understood that the system 100 may be applied to a variety of medical devices within the body for diagnosis or treatment.

[0037] The electrodes 128A, 128B of the sheath 102 can be used to locate a fixed point along tissue (e.g., the heart 110). In one example, the electrodes 128A, 128B can be used to detect the location of the His bundle 114 within the right atrium 112. The electrode 127 can be located on the diametrically opposite side of the distal end 127 of the sheath 102. The sheath 102 can be manipulated to advance the electrodes 128A, 128B along the atrial wall until a weak electrical signal from the His bundle 114 is identified. This typically occurs when the electrodes 128A and 128B are located on opposite sides of the His bundle 114. At this point, the sheath 102 can be manipulated to implant the anchor 108 into the atrial wall. As part of the electrical conduction system of the heart 110, the His bundle 114 transmits electrical impulses from the atrioventricular node to the ventricles of the heart 110. Placing lead 106 in or very close to bundle 114 allows the entire conductive system to be paced in a physiologically natural manner as the electrical impulses that regulate the heartbeat are conducted from right atrium 112 to the left and right ventricles via bundle 114. Pacing the ventricles in this manner closely simulates normal AV conduction within heart 110 and can greatly reduce or eliminate the risks associated with conventional CRT pacing.

[0038] The sheath 102 may include a sheath comprising a polymer, such as a thermoplastic elastomer, for example a polyether block amide (e.g., marketed under the name of Arkema, France). The sheath may provide columnar strength at the proximal and middle portions of the sheath 102 and deflectability at the distal portion of the sheath 102 .

[0039] The distal portion of the sheath 102 may include various insertion portions, such as Figure 1 Portions 124A-G are shown in the example of FIG. Portions 124A-G may include materials with different material properties, such as materials with different elastic moduli, bending moduli, or hardness, to provide one or more hinge points along lead 106. For example, in Figure 1 In the example, portion 124A may include a material with a durometer of 75; portions 124B, D, and F may include a material with a durometer of 55; portions 124C, E may have a durometer of 35; and distal portion 124G may have a durometer of 40.

[0040] Each of the individual portions 124A-G may be connected to one or more other corresponding portions 124A-G by gluing, ultrasonic welding, reflow heating, or other techniques. In a preferred arrangement, the distal portion 124G may be formed of a polymer that is softer than the material of the portions 124A, B, D, F, so as to provide an atraumatic tip for the sheath 102. In some embodiments, the polymer forming the portions 124A-G may include a radiopaque filler, such as barium sulfate, tungsten, bismuth trioxide, bismuth subcarbonate, bismuth oxychloride, etc. A polymer containing a radiopaque filler may be used for one or more different portions 124A-G of the sheath 102. As shown in FIG. Figure 3 As shown in the example of and further described herein, the lumen can extend continuously from the distal end 127 through the sheath 102 to the handle 104. The lumen can include a diameter slightly larger than the diameter of the lead 106. For example, for a 7 French pacing lead (approximately 2.33 mm in diameter), the lumen size is approximately 7.5 French (approximately 2.5 mm in diameter).

[0041] The catheter delivery system 100 may include a handle 104, a sheath connector 126 at a first end of the handle 104, and an interface 120. The handle 104 may be used to manipulate or guide the sheath 102, the lead 106, or a combination thereof within a patient's body. For example, the handle 104 may include a device for changing the length of one or more pull wires extending through the sheath 102, the lead 106, or both from the handle 104 to the distal end 127 of the sheath 102. For example, the handle 104 may include a rotary actuator operably engaged with the sheath 102, the lead 106, or both to manipulate the sheath 102 or the lead 106 using the one or more pull wires, or to extend or retract the sheath 102, the lead 106, or a combination thereof.

[0042] In one example, connector 126 may include a hemostatic valve. Sheath 102 may pass through connector 126, which provides a seal to minimize blood loss around sheath 102. Interface 120 may be an electrical connector for communicating electrodes, sensors, or other electrical or electromechanical devices of sheath 102, lead 106, or handle 104 to an electronic control unit (ECU) 116. In another example, interface 120 may include a hemostatic valve or may be combined with a hemostatic valve for transferring fluid to or from sheath 102 or lead 106. For example, handle 104 may include a catheter for connecting a source of flushing fluid. The catheter may pass through handle 104 for supplying flushing fluid to flush the lumen of sheath 102.

[0043] In some examples, a channel can be formed in an upper surface of the handle 104. The channel can be adapted to receive a sheath slitter including a blade for slitting the sheath 102 after the lead 106 is inserted into the patient, as will be explained more fully below.

[0044] In some examples, the catheter delivery system 100 may include an electronic control unit (ECU) 116 and a display 118. The ECU 116 may include, but is not limited to, a central processing unit (CPU), a graphics processing unit (GPU), a microprocessor, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a complementary metal oxide semiconductor (CMOS), etc. In some examples, the ECU may include a memory, such as a random access memory (RAM), a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), and an electrically erasable programmable read-only memory (EEPROM), a dynamic random access memory (DRAM), a static random access memory (SRAM), a flash memory, etc.

[0045] ECU 116 may provide means for controlling the operation of the various components of catheter delivery system 100. In one example, ECU 116 may also provide means for detecting electrophysiological features (e.g., signals) from tissue 116, the position and orientation of sheath 102 or lead 106 relative to the tissue and body. ECU 116 may also provide means for generating display signals for controlling display 118.

[0046] Display 118 can convey information to the physician to assist in lead placement, diagnosis, treatment, or a combination thereof. Display 118 can include one or more conventional computer monitors or other display devices. Display 118 can present a graphical user interface (GUI) to the physician. The GUI can include various information, including, for example, images of the geometry of the tissue, electrophysiological data (e.g., signals) associated with the tissue, graphs showing voltage levels of various electrodes over time, images of sheath 102 or lead 106 and other medical devices, and related information indicating the position of sheath 102 or lead 106 and other devices relative to the tissue.

[0047] The catheter delivery system 100 can be used in conjunction with an electric field based positioning system or a magnetic field based positioning system to determine the position of the sheath 102 or the position of the lead 106 in the body. For example, the catheter delivery system 100 can be used with an EnSite 3D scanner, such as that sold by St. Jude Medical, Inc. of St. Paul, Minnesota. TM NavX TMThe catheter delivery system 100 may be combined with an EnSite Precision Catheter Navigation and Location Mapping system, such as that sold by St. Jude Medical, Inc. of St. Paul, Minnesota, and described in, for example, U.S. Patent No. 7,263,397, entitled "Method and Apparatus for Catheter Navigation and Location Mapping in the Heart," the entire disclosure of which is incorporated herein by reference as if fully set forth herein. TM In other examples, the catheter delivery system 100 can be combined with a GMPS system provided by MediGuide, Inc. and as generally shown and described in, for example, U.S. Pat. No. 7,386,339, entitled “Medical Imaging and Navigation System,” the entire disclosure of which is incorporated herein by reference as if fully set forth herein.

[0048] In some examples, the catheter delivery system 100 can be combined with, for example, a mapping guide sheath, a separator, a handle, and an implantable cardiac pacing system, wherein the mapping guide sheath is described, for example, in PCT application number PCT / US2019 / 018329 entitled "Deflectable Mapping Guide Sheath for His Bundle Pacing," the entire disclosure of which is incorporated herein by reference as if fully set forth herein.

[0049] In a further embodiment, the catheter delivery system 100 can be combined with a steerable catheter as in U.S. Patent No. 6,979,312, entitled "Steerable Sheath Catheters," the entire disclosure of which is incorporated herein by reference as if fully set forth herein.

[0050] Figure 2An example of a detachable sheath 102 is shown, wherein the lead 106 extends through a lumen (e.g., lumen 142) of the sheath 102. In this example, the distal end of the lead 106 can be fixed to the tissue. The proximal end of the lead 106 can include a connector 130. In one example, the electrical connector 130 can be electrically coupled to a CRT device. Once the lead 106 is fixed, the sheath 102 can be withdrawn from the patient's body. In some examples, the lumen 142 of the sheath 102 can include a diameter that is the same, almost the same, or smaller (e.g., interference fit) as the diameter of the lead 106, so as to facilitate a compact design for navigation through the body. The reduced (e.g., minimal or missing) gap between the lumen 142 and the lead 106 can also provide a more accurate delivery of the lead 106, because the gap for the lead 106 to move in the lumen 142 is smaller. As a result, by sliding the sheath 102 on the lead connector 130, the sheath 102 may not be removed from the lead 106. To remove the sheath 102 from the lead 106, the blade 132 can separate the sheath in the longitudinal direction. Figure 2 As shown in the example of the embodiment of the present invention, the blade 132 can follow a cutting path 134. The cutting path 134 can extend from the proximal end of the sheath 102 to the distal end of the sheath 102 and extend between the electrodes 128A and 128B. For example, the blade 132 can cut through the thickness of the sheath 102 between the outer diameter and the inner diameter of the sheath 102. The cutting can be performed when the sheath 102 is withdrawn from the body. As previously described, the blade 132 can be included in a sheath slitting machine. The sheath slitting machine can be connected to the channel of the handle 104.

[0051] Figure 3 A cross section of sheath 102 is depicted, including lead 106 inserted into a lumen of sheath 102. Shell 136 of sheath 102 may include shell lumen 138. Lead liner 140 may be positioned along shell lumen 138, and lead liner 140 may include lead liner lumen 142. Lead 106 may be inserted into lead liner lumen 142.

[0052] The sheath 102 may include a pull wire 148 disposed within a pull wire lumen 144 of the sheath 102. A pull wire liner 146 may be disposed between the pull wire 148 and the pull wire lumen 144 to reduce friction between the pull wire 148 and the sheath 136. The pull wire 148 may be smaller in size than the pull wire liner 146 to provide clearance. Figure 3 The sheath 102 in the example can be steerable. For example, pressure or tension can be applied to the pull wire 148 to bend the sheath 102 along the bending plane 166. In other words, the bending plane can be located along a neutral axis or bending plane passing through the cross-section of the sheath.

[0053] The signal wires 158A, 158B may be electrically coupled between the respective electrodes 128A, 128B and the ECU 116. The signal wires 158A, 158B may be comprised of leads or traces. In some examples, the signal wires 158A, 158B may be comprised of copper wires, such as braided copper wires, or may be printed copper traces, such as printed copper traces disposed on a flexible circuit. Figure 3 In some examples, the signal lines 158A, 158B can be positioned along or near the bending plane 166 of the sheath 102. Therefore, when the sheath 102 bends during navigation of the sheath 102 and the lead 106, the strain on the signal lines 158A, 158B can be reduced. In some examples, the signal lines 158A, 158B can include signal line insulators 156A, 156B. The signal lines 158A, 158B can be positioned within corresponding signal line liner cavities 154A, 154B of the signal line liners 152A, 152B. The signal line liners 152A, 152B can be positioned within corresponding signal line cavities 150A, 150B

[0054] Lead liner 140 and signal line liner 152A, 152B may include a material having lubricating properties to reduce friction between sheath 136 and corresponding leads 106 and signal lines 158A, 158B. For example, lead liner 140 and signal line liner 152A, 152B may be composed of a polymer, such as polytetrafluoroethylene (PTFE).

[0055] Figure 3 An example of the location of the cutting path 134 is depicted. In some cases, the movement of the blade 132 along the sheath 102 may be unpredictable or irregular. If the blade 132 cuts into the signal line liner 152A, 152B, the signal line insulation layer 156A, 156B, or the signal line 158A, 158B, the electrical connection of the signal line 158A, 158B may be degraded or severed. In another example, a piece of the signal line liner 152A, 158B, the signal line insulation layer 156A, 156B, or the signal line 158A, 158B may be cut from the sheath 102, generating fragments. In some examples, the fragments may enter the patient's body, for example, the fragments may fall into the incision where the sheath 102 is inserted into the body. Due to manufacturing limitations, the internal components of the sheath 102 are not always sterile.

[0056] The sheath 102 may include a cutting protection device, such as a device for protecting the signal wires 158A, 158B, the pull wire 148, the corresponding liners 152A, 152B and 146, or a combination thereof from being damaged by the blade 132 during the cutting process. Figure 3In an example of the present invention, the sheath 102 may include one or more protective rails, such as rails 162A, B, to protect the blade 132 from cutting into elements of the sheath 102 that may generate debris, such as the signal line liner 152A, 152B, the signal line insulator 156A, 156B, or the signal line 158A, 158B. The rails 162A, 162B may guide the blade 132 along a desired cutting path 134 or within a desired cutting area in the sheath 102. The cutting path 134 or cutting area may be free of other elements of the sheath 102, such as the signal line liner 152A, 152B, the signal line insulator 156A, 156B, the signal line 158A, 158B, the pull line liner 146, or the pull line 148. The rails 162A, 162B may be constructed of a cut-resistant material, such as a material having a hardness similar to or harder than the material of the blade 132. For example, in one example, the rails 162A, 162B can be made of stainless steel, such as high-strength stainless steel or hardened stainless steel. In other examples, the rails 162A, 162B can be made of various materials, such as polymers (e.g., para-aramid, liquid crystal polyoxazole, liquid crystal polymer, etc.), ceramics, or others. Figure 3 As shown in the example of FIG. 1 , if the cutting path 134 of the blade 132 intersects the guide rails 162A, 162B, the guide rails 162A, 162B may be uncoated and the guide rail cavities 160A, 162B may be unlined to reduce the generation of debris. Figure 3 Two rails 162A, 162B are depicted having circular cross-sections, although other rail shapes and quantities are contemplated within the scope of the present disclosure.

[0057] In another example, the sheath 102 can include a sheath strip 164. The sheath strip 164 can include a different material than the sheath 136. For example, the sheath strip 164 can include a material that is easier for the blade 132 to cut through. In one example, the sheath 136 can include a material such as a 75 durometer polymer. The sheath strip 164 can include a lower durometer material than the sheath 136, such as a 35 durometer material. As a result, the blade 132 is urged along a cutting path that follows the lower resistance path of the sheath strip 164. Figure 3 In the example of FIG. 1 , the sheath strip 164 is located at a position radially 90 degrees to the bending plane 166. In other examples, the sheath 102 can include two sheath strips, such as symmetrically placed and diametrically opposed sheath strips.

[0058] Figure 4 and 5 A portion of the housing 102 is depicted in an isometric view with a majority of the housing 136 removed to show the exposed lead liner 140, signal lines 158A, 158B, and rails 162A, 162B. Figure 4A first side of the sheath 102 is shown, Figure 5 An opposing, second side of the sheath 102 is shown.

[0059] The electrodes 128A, 128B may include a partial ring around the outer diameter of the lead liner 140. For example, the electrodes 128A, 128B may include a c-shape and may be diametrically opposed about the bend plane 166. The pull wire 148 may be positioned along the sheath 102 at a 90° radial angle to the bend plane 166, such as Figure 3-5 For example, the pull wire 148 can be aligned with the center of the electrode 128B. The sheath 102 can include a pull ring 168 located at the proximal end of the electrodes 128A, 128B. The position of the pull ring 168 can be fixed within the sheath 102 to provide mechanical attachment and support to the pull wire 148.

[0060] The first signal line 158A can electrically couple the electrode 128A to the ECU 116, and the second signal line 158B can electrically couple the electrode 128B to the ECU 116. Figure 4 and 5 As shown in the example of FIG. 1 , the cutting protection device may include a first guide rail 162A and a second guide rail 162B. The signal lines 158A, 158B may be located between the guide rails 162A, 162B along the length of the sheath 102. The cutting zone may be located in a radial portion of the sheath 102 between the first guide rail 162A and the second guide rail 162B, wherein the radial portion is opposite to the location of the signal lines 158A, 158B, such as Fig.10 and 11 as shown in the example.

[0061] The guide rails 162A, 162B can be fixedly attached to the sheath 102 at the distal end. In one example, the guide rails 162A, 162B can be coupled to the pull ring 168. In another example, the distal ends of the guide rails 162A, 162B can be molded into the shell 136. At the proximal end, the guide rails 162A, 162B can be free floating, for example, within the handle 104. The proximal ends of the guide rails 162A, 162B can include stops to prevent the proximal ends of the guide rails 162A, 162B from sliding into the corresponding guide rail cavities 160A, 160B.

[0062] The radial positions (e.g., measured from the bending plane 166) of the various signal lines 158A, 158B and rails 162A, 162B may vary along the length of the sheath 102. For example, in the corresponding Figure 6-8The cross sections AA, BB, and CC depicted in FIG. 1 show various radial positions of the signal wires 158A, 158B; the guide rails 162A, B; and the pull wire 148 at different positions along the longitudinal direction of the sheath 102. In some examples, the cross section AA may correspond to the portion 124A; the cross section BB may correspond to the portion 124B, C, D, or E; and the cross section CC may correspond to the portion 124F or G.

[0063] Figure 6 1. The cross section of the sheath 102 at position AA is shown, and the corresponding signal line 158A, B can be positioned at a first radial offset angle γ1 relative to the bending plane 166. In some examples, the first radial offset angle γ1 can include a value between 10 degrees and 85 degrees, preferably between 30 degrees and 70 degrees, more preferably between 50 degrees and 60 degrees, or other values ​​therebetween. The corresponding guide rails 162A, B can be positioned at a second radial offset angle relative to the bending plane 166. In some examples, the second radial offset angle It may include values ​​between 10 and 80 degrees, preferably between 30 and 65 degrees, more preferably between 50 and 60 degrees, or other values ​​therebetween. Figure 6 In the example of FIG. 1 , signal lines 158A and 158B may be located at one o'clock and eleven o'clock positions, respectively. Guide rails 162A and 162B may be located at two o'clock and ten o'clock positions, respectively. The cutting zone may include a radial cutting zone angle α1 measured between first guide rail 162A and second guide rail 162B. For example, in Figure 6 In the example of , the cutting zone angle α1 can include a value between 45 degrees and 270 degrees, preferably between 300 degrees and 330 degrees, more preferably between 270 degrees and 350 degrees, or other angles. Therefore, the blade 132 can cut along the cutting path 134 at a position within the radial cutting zone angle α1 between the first guide rail 162A and the second guide rail 162B. In other words, the arrangement of the signal lines 158A, 158B, the guide rails 162A, 162B, and the pull wire 148 can provide a larger cutting zone at the proximal portion of the sheath 102 than other cross-sections (e.g., cross-sections BB or CC). For example, a larger cutting zone can provide a larger area for inserting the blade 132, for example, to increase the likelihood of inserting the blade into the cutting zone and reduce the likelihood of accidental insertion outside the cutting zone, where the sheath 102 may be damaged.

[0064] Figure 7A cross section of the sheath 102 at position BB is shown. In some examples, by routing the signal wires 158A, 158B along or near the bend plane 166, strain on the signal wires 158A, 158B (e.g., as a result of the bending of the sheath 102) can be reduced. Thus, when the sheath 102 is bent by the pull wire 148 to guide the lead 106 to a target location in the body (e.g., the His bundle 114), the strain applied to the signal wires 158A, 158B can be reduced. Positioning the signal wires 158A, 158B, the guide rails 162A, 162B, or both closer to the bend plane 166 than the corresponding location at the cross section AA can reduce the bending resistance of the sheath 102. For example, the signal wires 158A, 158B, the rails 162A, 162B, or both may be less strained when the respective positions are closer to the bend plane 166, and thus, the amount of force required to bend the sheath 102 (eg, tension applied to the pull wire 148) may be reduced.

[0065] At section BB, the corresponding signal lines 158A, 158B may be positioned at a first radial offset angle γ2 relative to the bending plane 166. In some examples, the first radial offset angle γ2 may include a value between 0 and 45 degrees, preferably between 0 and 20 degrees, more preferably between 0 and 10 degrees, or other values ​​therebetween. Figure 7 In the example of FIG. 1 , the first radial offset angle γ2 is depicted as zero degrees. The corresponding guide rails 162A, 162B may be offset relative to the curved plane 166 at a second radial offset angle In some examples, the second radial offset angle It may include values ​​between 0 and 45 degrees, preferably between 0 and 30 degrees, more preferably between 0 and 15 degrees, or other values ​​therebetween. Figure 7 In the example of FIG. 1 , signal lines 158A and 158B may be located at the three o'clock and nine o'clock positions, respectively. Guide rails 162A and 162B may be located at the four o'clock and eight o'clock positions, respectively. The cutting zone may include a radial angle α2 measured between first guide rail 162A and second guide rail 162B. For example, in Figure 7 In the example of, the cutting zone angle α2 may include a value between 90 and 210 degrees, preferably between 120 and 180 degrees, or other angles. Therefore, the blade 132 may cut along the cutting path 134 at a position within the radial cutting zone angle α2 between the first guide rail 162A and the second guide rail 162B.

[0066] Figure 8A cross section of the sheath 102 at position CC is shown. The signal lines 158A, 158B can be routed toward the respective electrodes 128A, 128B so that the signal lines 158A, 158B are electrically coupled to the respective electrodes 128A, 128B. In some examples, the electrical characteristics of the electrodes 128A, 128B can be improved by electrically coupling the signal lines 158A, 158B to the center of the respective electrodes 128A, 128B. For example, coupling the signal lines 158A, 158B at or near the center of the electrodes 128A, 128B can tune the electrodes 128A, 128B to improve signal detection, reduce impedance, etc. Thus, the distal ends of the signal lines 158A, 158B can be routed along the sheath 102 to respective locations that are 90 degrees or close to 90 degrees to the bending plane 166 (e.g., at Figure 1-8 In the example, the center of the corresponding electrodes 128A, 128B is located at this position).

[0067] exist Figure 8 In the example of , the corresponding signal lines 158A, 158B can be positioned at a first radial offset angle γ3 relative to the bending plane 166. In some examples, the first radial offset angle γ3 can include a value between 10 degrees and 90 degrees, preferably between 45 degrees and 90 degrees, more preferably between 75 degrees and 90 degrees, or other values ​​therebetween. For example, in Figure 8 In the example shown in FIG. 1 , signal lines 158A and 158B may be located at the five o'clock and eleven o'clock positions, respectively.

[0068] The corresponding guide rails 162A, 162B can be offset at a second radial angle relative to the curved plane 166. In some examples, the second radial offset angle The angle of the cutting zone may include a value between 0 and 5 degrees, preferably between 0 and 15 degrees, more preferably between 0 and 30 degrees, or other values ​​therebetween. For example, the rails 162A and 162B may be located at the eight o'clock and ten o'clock positions, respectively. The cutting zone may include a radial cutting zone angle α3 measured between the first rail 162A and the second rail 162B. For example, at Figure 8 In the example of the embodiment, the cutting zone angle α3 may include a value between 5 and 10 degrees, preferably between 10 and 30 degrees, more preferably between 30 and 60 degrees, or other angles. Therefore, the blade 132 can cut along the cutting path 134 at a position within the radial cutting zone angle α3 between the first guide rail 162A and the second guide rail 162B.

[0069] like Figure 8As further shown in the example of FIG. 1 , the cutting path 134 at the distal end of the sheath 102 can be located between the electrodes 128A, 128B. Thus, the guides 162A, 162B can protect the electrodes 128A, 128B from damage by the blade 132 and further generation of debris resulting from cutting one or more electrodes 128A, 128B. The guides 162A, 162B and the pull wire 148 can remain unchanged along the length of the sheath 102. For example, the signal wires 158A, 158B, the guides 162A, 162B, and the pull wire 148 can include a plurality of guides 162A, 162B, and the pull wire 148 along the entire length of the sheath 102. Figure 8 In another example, it should be understood that any of the examples discussed herein can be implemented with or without the pull wire 148, pull wire liner 146, or pull wire cavity 144.

[0070] Fig. 9 An example of a portion of the sheath 102 is depicted, such as at Figure 4 , 5 , 7 and 8. A portion of the housing 136 is removed to show the positions of various signal lines 158A, 158B and guide rails 162A, 162B. As shown in this example, the guide rail 162A transitions from a first radial position to a second radial position along the longitudinal direction of the sheath 102. For example, at the first radial position, the guide rail 162A may be located at a radial position approximately 90 degrees from the bending plane 166, or in other words, at the top of the sheath 102 (e.g., the twelve o'clock position at noon). At a second radial position at a distance L from the first radial position along the longitudinal direction of the sheath 102, the guide rail 162A may be located at or near the bending plane 166 (e.g., rotated 90 degrees from the first radial position). Therefore, the guide rail 162A may be oriented at a transition angle θ relative to the bending plane 166. As the transition angle increases, the likelihood of the blade 132 damaging or cutting the guide rail 162 increases. In some examples, a shallower transition angle may help to make it easier to cut along the sheath 102. In some examples, the transition angle θ may include a value between 0 and 45 degrees, or preferably between 10 and 25 degrees, or more preferably between 5 and 10 degrees, or other angles therebetween. Alternatively, the transition angle may be measured by a change in the radial offset angle (e.g., Δγ) of the rail 162A along the sheath 102 over a distance (e.g., distance L). In various examples, Δγ / L may include values ​​between 90 degrees over 1.5 inches, 90 degrees over 2.5 inches, etc.

[0071] exist Fig.10 and 11In the example of , the cutting zone 170 is shown between the first guide rail 162A and the second guide rail 162B. The shell 136 is depicted as being mostly cut away to show the features of the sheath 102 located underneath. The cutting zone angle (e.g., cutting zone angle α1) of the proximal portion of the sheath 102 (e.g., at or near cross section AA) can be greater than the cutting zone angle (e.g., cutting zone angle α2) of the middle portion of the sheath 102 (e.g., at or near cross section BB), and the cutting zone angle of the middle portion of the sheath 102 can be greater than the cutting zone angle (e.g., cutting zone angle α3) of the distal end of the sheath 102 (e.g., at or near cross section AA). In other words, the cutting zone 170 can be large at the distal end where the blade 132 is inserted into the sheath 102 to begin the separation cut along the cutting path. The cutting zone 170 can narrow toward the distal end of the sheath 102. Thus, the guide rails 162A, 162B may convey (eg, guide) the blade 132 toward the gap between the first electrode 128A and the second electrode 128B.

[0072] like Figure 4 , 5 , 10 and 11, the cutting path and the corresponding cutting area 170 can extend through the pull ring 168. In various examples, the pull ring 168 can be detachable. For example, the pull ring can include perforations, separation features, or a cuttable material that can be cut by the blade 132. In one example, the material of the pull ring can include gold or a similar soft material. Therefore, the blade 132 can pass through the pull ring 168 and through the entire length of the sheath 102 to remove the sheath 102 from the lead 106.

[0073] Fig.12 An example of a sheath strip 1264 positioned along a cutting zone 1270 is depicted. For example, the sheath strip 1264 can be used to guide the blade 132 along a cutting path. The sheath strip 1264 can include a softer material than the sheath 1236 to encourage the blade 132 to follow the sheath strip 1264 along the length of the sheath 1202 during a cutting operation. In some examples, the sheath strip 1264 can be used independently of a guide rail (e.g., guide rails 162A, 162B). For example, the sheath strip 1264 can be used alone as a cutting protection device. In other examples, the sheath strip 1264 can be used in conjunction with a guide rail (e.g., guide rails 162A, 162B). In further examples, the guide rails 162A, 162B can be a cutting protection device and can be used independently of the sheath strip 1264, such as Figure 4 shown.

[0074] Fig.13A cross-section of an example of a sheath 1302 including a pull wire 1348, a first rail 1362A, and a second rail 1362B is shown. The rails 1362A, 1362B can be electrically coupled between the ECU 116 and corresponding electrodes (e.g., electrodes 128A, 128B as shown and described herein). Thus, the rails 1362A, 1362B can be used as signal lines. The rails 1362A, 1362B can be constructed of a cut-resistant material, such as a material having a hardness similar to or harder than the material of the blade 132. For example, in one example, the rails 1362A, 1362B can be constructed of steel, stainless steel (e.g., high-strength stainless steel or hardened stainless steel), etc. The rails 1362A, 1362B can be located within corresponding rail cavities 1360A, 1360B in the shell 1336. In Fig.13 In some examples, rails 1362A, 1362B can be free of insulation (i.e., bare or uninsulated), and rail cavities 1360A, 1360B can be free of lining (i.e., unlined) to mitigate the formation of debris generated by cutting along sheath 1302 with blade 132. In some examples, sheath 1302 can include a sheath strip 1364, as further described herein.

[0075] Fig.14 An example of a sheath 1402 including a diverter 1484 is depicted, which is used to guide the blade 132 around one or more electrodes 1428A, 1428B and protect the blade 132 from cutting the electrodes 1428A, 1428B and forming fragments. As described herein, the sheath 1402 may include a first signal line 1458A, a second signal line 1458B, a first guide rail 1462A, and a second guide rail 1462B. The diverter 1484 can be located at the distal end of the first electrode 1428A. The diverter 1484 can be made of a material that resists cutting by the blade 132, such as a material that is similar in hardness to or harder than the material of the blade 132. For example, the diverter 1484 can be made of a polymer, ceramic, or metal, such as stainless steel (e.g., high-strength stainless steel or hardened stainless steel). In one example, the diverter 1484 may include a plurality of holes to help the diverter 1484 remain within the shell 1436. For example, as the shell material softens or melts during the assembly process, the material can flow into the hole and provide mechanical fixation as the material cools and hardens. The diverter 1484 may include one or more edges for guiding the blade 132 between the first electrode 1428A and the second electrode 1428B. In one example, the diverter 1484 may include a triangle or wedge shape to guide the blade 132 along a desired cutting path. One or more of the guide rails 1462A, 1462B may be directed to the diverter 1484 and the corresponding signal lines 1458A, 1458B may be shielded from the blade 132. Fig.14In the example of FIG. 1 , various signal lines 1458A, 1458B and rails 1462A, 1462B may be similar to Figure 4-11 In other examples, when the diverter 1484 is used, the wiring of various signal lines 1458A, 1458B and guide rails 1462A, 1462B can be simplified.

[0076] Figure 15-17 Depicted is a technique including several steps 1502-1506 for making the detachable sheath 102. As discussed further herein, the sheath 102 can include a cut protection feature, such as a plurality of rails 162A, 162B.

[0077] At 1502, the lead liner 140 can be placed on the cavity mandrel 1578; one or more signal line liners, such as the signal line liners 152A, 152B, can be placed on the corresponding signal line mandrels 1574A, 1574B; and the pull line liner 146 can be placed on the pull line mandrel 1572. The signal line liners 152A, 152B supported by the corresponding signal line mandrels 1574A, 1574B, the pull line liner 146 supported by the pull line mandrel 1572, and one or more guide mandrels 1567A, 1567B can be positioned along the outer diameter (or size) of the lead liner 140. In one example, the signal line liners 152A, 152B, the pull line liner 146, and the guide mandrels 1576A, 1576B can be removably fixed along the lead liner 140. For example, the signal line liner 152A, 152B, the pull line liner 146, and the guide rail mandrel 1576A, 1576B can be attached to the lead liner 140 using an adhesive such as cyanoacrylate or other adhesive. In some examples, the pull line mandrel 1572, the cavity mandrel 1578, and the signal line mandrel 1574A, 1574B can be made of steel or stainless steel, such as hardened stainless steel. In one example, the pull line mandrel 1572, the cavity mandrel 1578, and the signal line mandrel 1574A, 1574B can be uncoated. In a further example, the cavity mandrel 1578 can be an M7 mandrel, and the signal line mandrel can include a diameter of 0.007 inches.

[0078] In one example, the lead wire liner 140, the signal wire liner 152A, 152B and the pull wire liner 146 may include a lubricating material, such as a polymer, such as polytetrafluoroethylene (PTFE). In some examples, the guide rail mandrels 1576A, 1576B may include a stainless steel wire coated with polytetrafluoroethylene.

[0079] Braid 1580 can be around Fig.15Various components are shown, such as the pull line liner 146, the signal line liner 152A, 152B and the guide mandrel 1576A, 1576B. The braid 1580 can provide stability to the sheath 102. The braid 1580 can include a multi-wire metal wire that can be woven in a regular full-load pattern (one wire passes under two wires and then passes over two wires), a diamond pattern (two side-by-side wires alternately pass under two side-by-side wires and then pass over two side-by-side wires), a half-load diamond pattern (one wire passes under one wire and then passes over one wire), or other patterns known in the art. In some examples, the multi-wire metal wire can be round, with a diameter ranging from about 0.02 mm to about 0.2 mm, or flat, with a size ranging from about 0.01 mm thick and about 0.05 mm wide to about 0.1 mm thick and about 0.20 mm wide.

[0080] exist Fig.16 In step 1504 shown, the sheath 136 can be applied to the braid 1580, the pull line liner 146, and the signal line liner 152A, 152B. The sheath 136 can include a polymer, such as a thermoplastic elastomer, such as a polyamide (e.g., nylon 11, nylon 12, nylon 612, etc.), a polyester (e.g., polybutylene terephthalate, polyethylene terephthalate, etc.), a thermoplastic elastomer (e.g., poly(ether block amide) copolymer resin, poly(ether co-ester) block copolymer resin) and various thermoplastic polyurethane block copolymer resins. The sheath 136 can provide columnar strength at the proximal and middle portions of the sheath 102 and provide deflectability at the distal portion of the sheath 102.

[0081] In some examples, the sheath 136 can be extruded over the braid 1580, the wire liner 146, the signal wire liner 152A, 152B, the rail mandrel 1576A, 1576B, and the lead liner 140. In some examples, the sheath 136 can include an extruded profile, or multiple extruded profiles, which are placed over the braid 1580, the wire liner 146, the signal wire liner 152A, 152B, the rail mandrel 1576A, 1576B, and the lead liner 140. The assembly of the extruded profile, braid 1580, wire lining 146, wire mandrel 1572, signal wire lining 152A, 152B, signal wire mandrel 1574, guide mandrel 1576A, 1576B, lead liner 140 and cavity mandrel 1578 can be heated (for example, in a reflow oven) to melt one or more of the extruded profiles around the braid 1580, wire lining 146, signal wire lining 152A, 152B, guide mandrel 1576A, 1576B and lead liner 140.

[0082] like Figure 1As shown in the example of , the portions 124A-G may include various extruded profiles corresponding to the respective materials along the portions 124A-G (e.g., 75 durometer, 55 durometer, 40 durometer, or 35 durometer). The respective extruded portions 124A-G may be fused using a reflow oven. The respective portions 124A-G may be inserted along the distal portion of the sheath 102. As described above, the portions 124A-G may include materials with different material properties, such as materials with different elastic moduli, bending moduli, or hardness, to provide one or more hinge points along the lead 106. For example, portion 124A may include a material with a hardness of 75; portions 124B, D, F may include a material with a hardness of 55; portions 124C, E may have a hardness of 35; and the distal portion 124G may have a hardness of 40. Each of the respective portions 124A-G may be connected to one or more other respective portions 124A-G by gluing, ultrasonic welding, reflow heating, or other techniques. In a preferred arrangement, the distal portion 124G may be formed from a softer polymer than the material forming the portions 124A, B, D, F in order to provide an atraumatic tip for the sheath 102 .

[0083] In another example, the jacket 136 can be composed of multiple layers. The first thermoplastic polymer can be formed on the pull line lining 146, the signal line lining 152A, 152B, the guide rail mandrel 1576A, 1576B and the lead lining 140. Then, the braid 1580 can be placed on the first thermoplastic polymer layer. The second thermoplastic polymer layer can be applied to the first thermoplastic polymer layer. The thermoplastic polymers forming the corresponding first and second thermoplastic polymer jacket layers can be the same, similar or different. However, they should be chemically compatible or miscible so that the polymer of the second thermoplastic polymer layer (e.g., the shell layer) is firmly adhered to the first thermoplastic polymer layer when the first thermoplastic polymer layer (e.g., the inner shell layer) is extruded or melted thereon. This strong bonding can be achieved by using a polymer with a relatively low melting temperature in the first thermoplastic polymer layer and a polymer with a relatively high melting temperature in the second thermoplastic polymer layer. As a result, the polymer of the second thermoplastic polymer layer will heat fuse and firmly adhere to the first thermoplastic polymer layer, embedding the braid 1580 therebetween.

[0084] In a further example, a first thermoplastic polymer can be formed on the lead liner 140. The wire liner 146, the signal line liner 152A, 152B and the rail mandrel 1576A, 1576B can then be positioned along the lead liner 140. In some cases, the wire liner 146, the signal line liner 152A, 152B, the rail mandrel 1576A, 1576B can be attached to the lead liner 140 using an adhesive, as further described herein. Then, the braid 1580 can be placed on the first thermoplastic polymer layer, and the second thermoplastic polymer layer can be applied on the first thermoplastic polymer layer.

[0085] In some examples, the jacket 136 may include a jacket strip 164. The jacket strip 164 may include a different material than the jacket 138. In various examples, the jacket strip 164 may be extruded with the jacket material, or in other examples, the jacket strip 164 may be included in one or more extruded profiles and then fused as previously described. Fig.16 In the example of , the shell strip 164 is located at a position radially 90 degrees to the bending plane 166. In other examples, the sheath 102 may include two shell strips, such as symmetrically placed and diametrically opposed shell strips. The symmetrically opposed shell strips can help to uniformly squeeze, for example, by reducing inconsistent shrinkage or asymmetric deformation during the application of the shell 136. The shell strip 164 may include a material that is easier for the blade 132 to cut through. In one example, the shell 136 may include a material such as a 75 durometer polymer. The shell strip 164 may include a material with a lower durometer than the shell 136, such as a 35 durometer material. Therefore, the blade 132 is urged to travel along the cutting path 134, and the cutting path 134 travels along the lower resistance path of the shell strip 164.

[0086] In some examples, the sheath 136 can include a radiopaque filler, such as barium sulfate, tungsten, bismuth trioxide, bismuth subcarbonate, bismuth oxychloride, etc. A polymer containing a radiopaque filler can be used for one or more of the different portions 124A-G of the sheath 102. In another example, the sheath 136 can be encased in a sleeve, such as a polyimide sleeve. In some examples, the sleeve can be a shrink wrap tube that is applied to the sheath 136 during the reflow process.

[0087] Once the sheath 136 is applied, the mandrels can be removed. For example, the wire mandrel 1572, cavity mandrel 1578, and signal wire mandrel 1574A, 1574B can be removed from their respective wire liner 146 and signal wire liner 152A, 152B. The wire liner 146, lead liner 140, and signal wire liner 152A, 152B can facilitate the removal of the wire mandrel 1572, cavity mandrel 1578, and signal wire mandrel 1574A, 1574B due to the lubrication of the wire liner 146, lead liner 140, and signal wire liner 152A, 152B. Similarly, the rail mandrel 1576A, 1576B can include a polytetrafluoroethylene coating to facilitate removal from the rail cavities 160A, 160B of the sheath 136. Once the pull wire mandrel 1572, cavity mandrel 1578, signal wire mandrel 1574A, 1574B and guide rail mandrel 1576A, 1576B are removed, the pull wire cavity 144, lead wire liner cavity 142, signal wire liner cavity 154A, 154B and guide rail cavity 160A, 160B are ready for assembly of the pull wire 148, lead wire 106, signal wire 158A, 158B and guide rails 162A, 162B.

[0088] At 1506, the pull wire 148, the lead wire 106, the signal wire 158A, 158B and the guide rails 162A, 162B may be inserted into the corresponding pull wire liner cavity 144, the lead wire liner cavity 142, the signal wire liner cavity 154A, 154B and the guide rail cavity 160A, 160B, as shown in FIG. Fig.17 For example, the sheath 102 may include a pull wire 148 disposed within a pull wire liner 146 to reduce friction between the pull wire 148 and the sheath 136. The size of the pull wire 148 may be smaller than the inner size of the pull wire liner 146 to provide clearance.

[0089] The signal wires 158A, B may be inserted into the corresponding signal wire liner cavities 154A, B of the signal wire liners 152A, B. The signal wires 158A, B may be electrically coupled between the corresponding electrodes 128A, 128B and the ECU 116, such as Figure 1 The signal lines 158A, 158B may be formed of leads or traces. In some examples, the signal lines 158A, 158B may be formed of copper wires, such as braided copper wires, or may be printed copper traces, such as printed copper traces disposed on a flexible circuit. Fig.17As shown in the example of FIG. 1 , the signal lines 158A, 158B can be positioned along or near the bend plane 166. Therefore, when the sheath 102 bends during navigation of the sheath 102 and the lead 106, the strain on the signal lines 158A, 158B can be reduced. In some examples, the signal lines 158A, 158B can include signal line insulators 156A, 156B. The signal lines 158A, 158B can be located within corresponding signal line liner cavities 154A, 154B of the signal line liners 152A, 152B. The signal line liners 152A, 152B can be located within corresponding signal line cavities 150A, 150B

[0090] One or more guide rails 162A, B can be inserted into corresponding guide rail cavities 160A, B. The guide rails 162A, B can guide the blade along a desired cutting path or within a desired cutting area in the sheath 102. The cutting path or cutting area can be free of other elements of the sheath 102, such as the signal line lining 152A, B, the signal line insulator 156A, B, the signal line 158A, 158B, the pull line lining 146 or the pull line 148. The guide rails 162A, 162B can be made of a cut-resistant material, such as a material having a hardness similar to or harder than the material of the blade 132. For example, in one example, the guide rails 162A, 162B can be made of steel, stainless steel (e.g., high-strength stainless steel or hardened stainless steel), etc. In other examples, the guide rails 162A, 162B can be made of various materials, such as polymers (e.g., para-aramid, liquid crystal polyoxazole, liquid crystal polymer, etc.), ceramics, or others. As Fig.17 As shown in the example of FIG. 1 , if the cutting path 134 of the blade 132 intersects the guide rails 162A, 162B, the guide rails 162A, 162B may be uncoated and the guide rail cavities 160A, 162B may be unlined to reduce the generation of debris. Fig.17 Two rails 162A, 162B having circular cross-sections are depicted, but other rail shapes and quantities are contemplated within the scope of the present disclosure. Thus, the sheath 102 can include a cutting protection device, such as a device for protecting the signal wires 158A, 158B, the signal wire liner 152A, 152B, the pull wire 148, the pull wire liner 146, or a combination thereof from being damaged by a blade during the cutting and separation process.

[0091] Fig.18 An example of a sheath 102 in a partially assembled state is shown. In this example, the tip portion 1882 can be assembled to the remainder of the sheath 102 (e.g., the distal portion of the sheath 102). The tip portion 1882 can include the pull ring 168 and the plurality of electrodes 128A, B. The distal portions of the pull wire 148, the signal wires 158A, 158B, and the guide rails 162A, 162B can extend from the distal portion of the housing 136, as shown in FIG. Fig.18 As shown in the example. Fig.19 As shown, the signal wires 158A, 158B can be electrically coupled to the corresponding electrodes 128A, 128B. For example, the signal wires 158A, 158B can be welded, crimped, or otherwise communicatively coupled to the electrodes 128A, 128B. The pull wire 148 can be mechanically coupled to the pull ring 168. The tip portion 1882 can include one or more cavities to accommodate the pull wire 148, the signal wires 158A, B, and the guide rails 162A, B. When the pull wire 148, the signal wires 158A, B, and the guide rails 162A, B are inserted into the cavity or the corresponding cavity, the sheath 102 and the tip portion 1882 can be coupled together, as shown. Fig.19 In one example, a reflow oven can be used to fuse the tip portion 1882 to the remainder of the sheath 102 and the shell 136. In other examples, other methods can be used to melt or fuse the tip portion 1882 to the remainder of the sheath 102 and the shell 136. In some examples, the guide rails 162A, B can be coupled to the tip portion 1882 by fusing the tip portion 1882 around the guide rails 162A, B, mechanically coupling the distal ends of the guide rails 162A, B to the pull ring 168, or a combination thereof.

[0092] Fig. 20 An example of a sheath 2002 including a plurality of sheath strips 2064A, B is shown. The sheath 2002 may include a sheath 2036, at least one pull wire 2048, one or more signal wires 2058A, B, and one or more guide rails 2062A, B, as previously described. The plurality of sheath strips may include a first sheath strip 2064A and a second sheath strip 2064B. Fig. 20 In the example of FIG. 1 , the first and second jacket strips 2064A, B may be infused with additives to increase the cut resistance of the jacket strips 2064A, B. For example, the jacket strips 2064A, B may be infused with particles, such as tungsten, to increase the cut resistance. A blade, such as blade 132, may be inserted into the middle jacket strip 2082 between the first jacket strip 2064A and the second jacket strip 2064B. Fig. 20As shown in the example of FIG. 1 , the first sheath strip 2064A can be offset from the second sheath strip 2064B by a radial angle, the value of which may include, but is not limited to, between 10 and 270 degrees; preferably between 45 and 180 degrees, and more preferably between 90 and 120 degrees. In various examples, the middle strip 2082 may include the same material as the rest of the sheath 2036, or may include a different material, such as a softer material, to facilitate separation of the sheath 2002 along the middle strip 2082. Because the first sheath strip 2064A and the second sheath strip 2064B resist cutting, the blade may be urged to follow the middle strip 2082. Thus, the first and second strips 2064A, 2064B can provide a cut prevention device for reducing damage or fragments caused by a blade cutting into: the signal line liner 2052A, 2052B; the signal line insulator 2056A, B; the signal line 2058A, B; the pull line liner 2046; or the pull line 2048.

[0093] Although several embodiments have been described above with a certain degree of particularity, those skilled in the art may make various changes to the disclosed embodiments without departing from the spirit of the present disclosure. All content contained in the above description or shown in the accompanying drawings should be interpreted as merely illustrative and not restrictive. Changes in details or structure may be made without departing from the present teachings. The preceding description and the following claims are intended to cover all such modifications and variations.

[0094] Various embodiments of various devices, systems and methods are described herein. Many specific details are set forth to provide a thorough understanding of the overall structure, function, manufacture and use of the embodiments described in the specification and shown in the drawings. However, those skilled in the art will appreciate that the embodiments can be implemented without these specific details. In other cases, well-known operations, components and elements are not described in detail to avoid confusing the embodiments described in the specification. Those of ordinary skill in the art will appreciate that the embodiments described and illustrated herein are non-limiting examples, and it is therefore understood that the specific structural and functional details disclosed herein may be representative and do not necessarily limit the scope of the embodiments, which are limited only by the appended claims.

[0095] References throughout the specification to "various embodiments," "some embodiments," "one embodiment," "an embodiment," etc. mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in at least one embodiment. Thus, appearances of the phrases "in various embodiments," "in some embodiments," "in one embodiment," "in an embodiment," etc. throughout the specification do not necessarily all refer to the same embodiment. Furthermore, particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Thus, particular features, structures, or characteristics illustrated or described in conjunction with one embodiment may be combined, in whole or in part, with features, structures, or characteristics of one or more other embodiments without limitation.

[0096] It should be understood that the terms "proximal end" and "distal end" may be used throughout the specification with reference to the end of an instrument that a clinician manipulates to treat a patient. The term "proximal end" refers to the portion of the instrument closest to the clinician, and the term "distal end" refers to the portion farthest from the clinician. It should also be understood that for simplicity and clarity, spatial terms such as "vertical," "horizontal," "upward," and "downward" may be used herein with respect to the illustrated embodiments. However, surgical instruments may be used in many orientations and positions, and these terms are not restrictive and absolute.

[0097] Any patent, publication, or other public material, in whole or in part, deemed to be incorporated herein by reference, is incorporated herein only to the extent that the incorporated material does not conflict with existing definitions, statements, or other public material set forth in this disclosure. Therefore, to the extent necessary, the disclosure explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, if deemed to be incorporated herein by reference, but conflicts with existing definitions, statements, or other public material set forth herein, will be incorporated only to the extent that there is no conflict between the incorporated material and the existing public material.

Claims

1. A detachable sheath, comprising: a sheath extending from the proximal end to the distal end and comprising a sheath cavity; a plurality of electrodes diametrically opposed to one another across the sheath lumen at the distal end; as well as A plurality of rails extend from the proximal end to the distal end, wherein the plurality of rails define a cutting zone extending between the plurality of electrodes.

2. The detachable sheath of claim 1, wherein the plurality of electrodes comprises partial rings.

3. The detachable sheath of claim 1, wherein the plurality of electrodes are diametrically opposed about a bending plane of the detachable sheath.

4. The detachable sheath of claim 1, wherein the cutting zone at the proximal end is larger than the cutting zone at the distal end.

5. The detachable sheath of claim 4, wherein the cutting zone has a cutting zone angle, wherein the cutting zone angle is greater than 180 degrees at the proximal end, and wherein the cutting zone angle is less than 180 degrees at the distal end.

6. The detachable sheath of claim 1, further comprising a pull ring coupled to the pull wire, wherein the pull ring is detachable.

7. The detachable sheath of claim 6, wherein the pull ring is made of a detachable material having a softness at least as soft as gold.

8. The detachable sheath of claim 6, wherein the pull tab includes one or more perforations or detachment features.

9. The detachable sheath of claim 1, further comprising a lead liner positioned along the shell cavity.

10. The detachable sheath of claim 9, wherein the lead liner comprises a fluoropolymer material having lubricating properties.

11. The detachable sheath of claim 1, further comprising a signal line disposed within the sheath and electrically coupled to a first electrode of the plurality of electrodes.

12. The detachable sheath of claim 11, wherein the plurality of guide rails are located between the signal line on a first side of the detachable sheath and the cutting zone on a second side of the detachable sheath diametrically opposite the first side.

13. The detachable sheath of claim 11, further comprising a second signal line disposed within the sheath and electrically coupled to a second electrode of the plurality of electrodes.

14. The detachable sheath of claim 11, wherein the signal line is positioned along a bending plane of the detachable sheath.

15. The detachable sheath of claim 1, wherein the sheath comprises a sheath strip extending through the cutting zone, and wherein a sheath strip material of the sheath strip is softer than a sheath material of the sheath.

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