US20190060002A1 - Sensor assembly tethered within catheter wall - Google Patents

Abstract

A distal tip assembly for an elongate medical device having an axis comprises a shaft having a proximal end portion, a distal end portion, a wall, and a central lumen extending axially between said proximal end portion and said distal end portion. The distal tip assembly further comprises a position sensor disposed in an outer sleeve such that the sensor can shift relative to the sleeve. The sleeve is disposed at least in part in the wall and is substantially fixed thereto.

Description

BACKGROUND OF THE INVENTIONCROSS-REFERENCE TO RELATED APPLICATIONS
• This application is a divisional of U.S. application Ser. No. 14/519,313, filed 21 Oct. 2014 (the '313 application), which is a continuation of U.S. application Ser. No. 13/098,969, filed 02 May 2011 (the '969 application), now U.S. Pat. No. 8,880,147, which is hereby incorporated by reference as though fully set forth herein.
a. Field of the Invention
• The present disclosure relates to a family of positioning sensors for a medical device and a method for mounting an electromagnetic positioning sensor on a medical device to avoid potential damage due to compression and tension forces and the like.
b. Background Art
• Various diagnostic and therapeutic procedures in or on the body of a patient, such as in the heart or elsewhere in the circulatory system, can be performed or facilitated by inserting an electrophysiology (EP) catheter into a body lumen and thereafter navigating the diagnostic or therapeutic EP catheter to the target anatomical site. The EP catheter can include one or more electrodes to be used for therapeutic (e.g., ablation), diagnostic, or other purposes.
• For certain procedures, it is desirable for the distal end of an EP catheter to have a particular curve or shape or to include uni- or bi-directional deflection elements, for example. For example, some ablation or mapping procedures on certain portions of the heart or the vasculature around the heart, such as the superior pulmonary vein, can be simplified through the use of an EP catheter having a lariat or spiral shape on its distal end. In order to achieve the desired shape, an EP catheter can incorporate one or more shape wires that can be preformed to the desired shape, deformed (e.g., via loading) to guide the catheter to the target anatomical site, then unloaded such that the shape wire—and thus the catheter—returns to the preformed desired shape.
• It is also known to configure straight EP catheters (i.e., without shape wires) to include one or more electromagnetic field (position) sensors for navigating the catheter to the target anatomical site. While enabling sensor-based navigation functionality, a straight EP catheter as described above does not have the same applicability to certain EP procedures as does a shaped EP catheter.
• There is therefore a need for a catheter that incorporates a shape wire and one or more electromagnetic position sensors that minimizes or eliminates one or more of the problems set forth above.
BRIEF SUMMARY OF THE INVENTION
• This disclosure is directed to an elongate medical device configured for use with a positioning system (i.e., the device includes at least one position sensor, such as an impedance-sensing electrode, a metallic/magnetically-responsive coil, and/or an acoustically-responsive element or the like). A distal tip assembly for an exemplary elongate medical device having an axis includes a shaft having a proximal end portion, a distal end portion, a wall, and a central lumen extending axially between the proximal end portion and the distal end portion. The assembly further includes one of an electromagnetic position sensor, an impedance-sensing electrode, and an acoustically-responsive element disposed in an outer sleeve and/or coupled to a stress-reduction flex circuit or other member. The mechanical stress imparted to the sensor is reduced because the sleeve substantially separates the sensor from the wall, so the sensor can potentially shift relative to the sleeve, the wall, or any anchoring location therefor. The sleeve is disposed, at least in part, in the wall and is fixed thereto in a stress-relieving configuration. In an embodiment, the assembly is incorporated into a device that also includes a shape wire for providing a desired preformed shape. The sensor-in-sleeve arrangement described above allows the sensor to move with respect to the shape wire or other deflection mechanism when assembled for use in a medical procedure. This permitted movement avoids damage to the sensor that can otherwise occur had the sensor been rigidly fixed in the wall.
• A method of fabricating a distal tip assembly for the exemplary device includes a number of steps that include providing a first shaft layer and placing, at a distal end portion of the elongate medical device, a position sensor assembly on the first shaft layer. The position sensor assembly includes a tubular core, an electrically-conductive coil wound on said core, and an outer sleeve surrounding the core and the coil. The method further includes applying a second shaft layer radially-outwardly of the position sensor assembly and of the first shaft layer, and subjecting the tip assembly to a reflow lamination process. In the reflow lamination process, the first shaft layer and the second shaft layer bond to an outer surface of the sleeve, and the coil and the core can shift within the sleeve.
• These and other benefits, features, and capabilities are provided according to the structures, systems, and methods depicted, described and claimed herein.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a simplified view of a first embodiment of an elongate medical device, with a distal lariat portion, within a human heart.
• FIGS. 2-6 illustrate a method of fabricating a distal tip assembly for the device shown inFIG. 1.
• FIG. 7 is a top view of the distal tip assembly of the first embodiment at the stage of fabrication shown inFIG. 5.
• FIGS. 8 and 8A are cross-sectional views of the distal tip assembly of the first embodiment.
• FIG. 9 is an isometric view of a distal end portion of the first embodiment.
• FIG. 10 is a cross-sectional view of the extreme distal end of the first embodiment, taken substantially along line10-10 inFIG. 9.
• FIG. 11 is an isometric view of the first embodiment, including a proximal end portion.
• FIG. 12 is a side view of a distal portion of another embodiment of an elongate medical device, having a flex circuit, with a portion of the outer jacket cut away.
• FIG. 13 is a cross-sectional view of an embodiment of an elongate medical device, taken substantially along line13-13 inFIG. 12.
• FIGS. 14-17 are various isometric and plan views of an embodiment of a flex circuit according to the disclosure.
• FIGS. 18-19 are plan views of an embodiment of a flex circuit according to the instant disclosure.
DETAILED DESCRIPTION OF THE INVENTION
• Referring now to the drawings wherein like reference numerals are used to identify identical components in the various views,FIG. 1 is a simplified view of a first embodiment of an elongatemedical device10.Device10, shown as a catheter, is disposed in the left atrium of ahuman heart12. As depicted,device10 comprises a spiral electrophysiology (EP) mapping catheter incorporating at least one electromagnetic-, impedance-, or acoustic-based position sensor, though the present invention can also find use with a spiral EP ablation catheter, another EP catheter, or another medical device for which an electromagnetic position sensor would be useful. A spiral mapping catheter, such ascatheter10, can be particularly useful for mapping ingress and egress points of the human heart, such as superiorpulmonary vein14, as well as for other portions of the human vasculature. An EP mapping catheter can be used in the heart and vasculature to collect EP data as described in greater detail in commonly-owned U.S. Pat. No. 7,774,051, entitled “System and Method for Mapping Electrophysiology Information Onto Complex Geometry,” which is hereby incorporated by reference in its entirety.Device10, or another device employing an electromagnetic position sensor and/or EP electrodes, can be used with a variety of navigation and mapping systems such as, for example, an ENSITE VELOCITY system running a version of the ENSITE NavX™ software commercially available from St. Jude Medical, Inc., of St. Paul, Minn. and as also seen generally by reference to U.S. Pat. No. 7,263,397 entitled “Method and Apparatus for Catheter Navigation and Location and Mapping in the Heart” to Hauck et al., owned by the common assignee of the present disclosure, and hereby incorporated by reference in its entirety.Device10 can also find use with other known technologies for locating/navigating a catheter in space (and for visualization), including for example, the CARTO visualization and location system of Biosense Webster, Inc., (e.g., as exemplified by U.S. Pat. No. 6,690,963 entitled “System for Determining the Location and Orientation of an Invasive Medical Instrument,” hereby incorporated by reference in its entirety), the AURORA® system of Northern Digital Inc., a magnetic field based localization system such as the gMPS system based on technology from MediGuide Ltd. of Haifa, Israel and now owned by St. Jude Medical, Inc. (e.g., as exemplified by U.S. Pat. Nos. 7,386,339, 7,197,354 and 6,233,476, all of which are hereby incorporated by reference in their entireties) or a hybrid magnetic field-impedance based system, such as the CARTO 3 visualization and location system of Biosense Webster, Inc. (e.g., as exemplified by U.S. Pat. Nos. 7,536,218, and 7,848,789 both of which are hereby incorporated by reference in its entirety).
• An EP catheter employing one or more shape wires can include one or more electromagnetic position sensors for navigating the catheter to the target anatomical site with one or more of the technologies described above. Assembling electromagnetic coil sensors within the space constraints of a catheter without sacrificing sensitivity presents various design and manufacturing challenges. One such challenge is incorporating a sensor in a portion of a catheter that can be bent by a shape wire in a way that can place stress on the shaft of the catheter and on components disposed within the shaft, such as an electromagnetic sensor.
• FIGS. 2-6 are diagrammatic cross-sectional side views of a reflow mandrel assembly in various stages of build-up in a method of manufacture of adistal tip assembly40 with an electromagnetic position sensor fordevice10. It should be understood that although gaps are shown between the several layers of material, such gaps are shown for visual clarity and can or cannot be present in the actual manufacturing process and final product. Elements shown inFIGS. 2-6 are not necessarily to scale. Furthermore, “assembly40” is used herein to refer both to the distal tip assembly as it is built up and constructed, as well as to the finished distal tip assembly.
• FIG. 2 shows a mandrel16 having a central axis “A,” adistal end portion18, and aproximal end portion20. Mandrel16 can be circular in radial cross-section and have a desired length in view of the elongate medical device or portion thereof to be manufactured. Mandrel16 can have grooves to facilitate the application and removal of materials, or can be smooth.
• As shown inFIG. 3, a first segment22₁of a first shaft layer22 can first be placed over mandrel16. First shaft layer22 can consist of multiple segments22₁,22₂,22₃(best shown inFIGS. 5 and 6). First shaft layer22 can be any suitable tubing material known in the art of medical instruments, such as engineered nylon resins and plastics, including but not limited an elastomer commercially available under the trade designation PEBAX® from Arkema, Inc. of a suitable durometer, melting temperature and/or other characteristics. First segment22₁can have an axial length configured to be substantially equal to the length of a sensor or sensor assembly to be incorporated intodistal tip assembly40.
• Aposition sensor assembly24 can be provided for position sensing and device navigation in thefinished device10. As shown inFIG. 4,position sensor assembly24 can be placed on top of first shaft layer22. In the illustrated first embodiment,sensor assembly24 is placed on first segment22₁.Sensor assembly24 can include asensor26 within an outer protection sleeve, or tube,28.Sensor26 can be an electromagnetic field-detecting coil-type sensor, as shown.Electromagnetic coil sensor26 can comprise atubular core30 and an electrically-conductive coil32 wound aroundcore30.Core30 can be a hollow tube made of a polymer with a relatively high melting point, such as polyimide, so as to maintain shape during a high-temperature reflow lamination process, such as seen by reference to co-pending U.S. patent application Ser. No. 12/982,120, entitled “Electromagnetic Coil Sensor for a Medical Device,” hereby incorporated by reference in its entirety.Core30 can also be solid, rather than hollow (shown inFIG. 13).Core30 can have a central axis “B” that is substantially parallel with, but radially offset from, mandrel central axis “A.” Because axis “A” can also be the central axis ofdevice10 anddistal tip assembly40, sensor axis “B” can be substantially parallel with, but radially offset from, axis “A” ofdevice10.Coil32 can be made of electrically-conductive wire wrapped aroundcore30.Coil32 is not limited in number or pitch of windings, or type of wire, but instead can be tailored to suit a particular application ofsensor26.Coil32 can have one or more free leads34 at its proximal end for connection to one ormore wires36.Wiring36 can be coupled to coil leads34 and extend towards the proximal end ofdevice10 to provide electrical connection with a positioning system, navigation system, or other system. One ormore wires36 can be in the form of a twisted-pair (TP) cable as shown inFIGS. 4-6, can be a coaxial cable, or can be another electrical signal or power cable known in the art.
• Outer sleeve28 can be provided to preventsensor26 from being directly embedded in the shaft offinished device10.Sleeve28 can extend both distally and proximally beyond the axial length of sensor26 (i.e., bothcore30 and coil32) and can fully circumferentially surround sensor26 (again, bothcore30 and coil32).Sleeve28 can have a length that is substantially the same as the length of first shaft layer segment22₁.Sleeve28 can be made of expanded polytetrafluoroethylene (ePTFE), polytetrafluoroethylene (PTFE), polyimide, fluorinated ethylene propylene (FEP), polyether ether ketone (PEEK), or other material interposed between first shaft layer22 and other shaft layers andsensor26, which prevents such shaft layers from encapsulating and thus rigidly fixingsensor26 therein during a high-temperature reflow lamination process.Sleeve28 can be circumferentially sealed and can be sealed at its distal end, but can have a hole at its proximal end for wiring36 or sensor coil leads34 to extend into or out ofsleeve28.
• As shown inFIG. 5, the rest of first shaft layer22 can then be placed on mandrel16—i.e., segments22₂and22₃can be placed proximally and distally of segment22₁.Wiring36 can be disposed radially-inwardly of first shaft layer segment22₂—i.e., the segment axially proximal ofsensor26—so that wiring36 can be disposed in the central lumen of the finished device. Segment22₂is shown as asymmetrical across axis “A” tobetter show wiring36, but segment22₂can be applied as a substantially symmetrical segment, such as a tube. Segments22₁,22₂,22₃can have axial lengths and radial thicknesses that are different from each other, or they can have the same relative lengths and thicknesses. As noted hereinabove, the axial length of segment22₁can be selected relative to the size ofsensor26 orsensor assembly24. The axial lengths of segments22₂and22₃can be selected according to the desired placement of one ormore sensors26 indevice10. Segments22₂and22₃can have thicknesses substantially equal to each other, which can be greater than the thickness of segment22₁.
• FIG. 7 is a top view ofsensor assembly26 disposed on—i.e., laying on—first layer segment22₁at the same stage of construction asFIG. 5.Sensor core30 has an axial length L₁, which can be less than axial length L₂ofsleeve28, which can be substantially equal to length L₃of first shaft segment22₁. Sleeve axial length L₂is shown smaller than first shaft segment length L₃for visual clarity, though L₂can be substantially equal to L₃or can even be larger than
• L₃.
• Asecond shaft layer38 can then be placed over the entiredistal tip assembly40, as shown inFIG. 6, including first shaft layer22 andsensor assembly24.Second shaft layer38 can be the same material as the first shaft layer (i.e., a melt-processing polymer such as) PEBAX® .Second shaft layer38 can have the same radial thickness as thicker first shaft layers22₂and22₃.
• Aftersecond shaft layer38 is added to the assembly, the assembly can be subjected to a reflow lamination process, which involves heating the assembly until first shaft layer22 andsecond shaft layer38 flow and redistribute around the circumference of the assembly, bonding with an outer surface ofsleeve28 to embedsleeve28. In one embodiment, the reflow process includes heating the assembly to about 450° F. (e.g., in an oven-like appliance), though the reflow temperature can vary for other embodiments. The assembly can then be cooled, after which first shaft layer22 andsecond shaft layer38 form aunitary shaft42.Shaft42 can have a proximal end portion and distal end portion coincident with mandrelproximal end portion20 and mandreldistal end portion18, respectively.
• FIGS. 8 and 8A illustratedistal tip assembly40 after the reflow lamination process and after the removal of mandrel16.Shaft42 has acentral lumen44 extending along axis “A” (formerly the central axis of mandrel16) between the proximal end portion ofshaft42 and the distal end portion ofshaft42.Protection sleeve28 can be embedded within awall50 ofshaft42, but the outer diameter (O.D.) ofsensor26 can be separated from, or at least not bonded to, the inner diameter (ID.) ofsleeve28, sosensor26 can remain free to move (e.g., shift) relative tosleeve28. It should be understood that although a relatively large gap is shown between the I.D. ofsleeve28 and the O.D. of sensor26 (i.e., outside surface of coil32),sleeve28 can be relatively tight tocoil32 andcore30 after the reflow lamination process, while still allowingcoil32 andcore30 to shift relative tosleeve28 andwall50.
• FIG. 9 is an isometric view of adistal end portion54 ofdevice10 after the addition of atip electrode46 and a shape wire48 (best shown inFIG. 10) todistal tip assembly40.Shape wire48 can extend throughdistal end portion54 and further proximally throughdevice10 and can be configured to establish a pre-defined shape fordistal end portion54. Indevice10,shape wire48 establishes a lariat shape along a plane substantially perpendicular to device axis “A”.Shape wire48 can be a super-elastic or shape memory metallic alloy, such as Nitinol, or another super-elastic or shape memory material. In a super-elastic embodiment,shape wire48 can be pre-formed to a desired shape for a particular portion ofdevice10.Device10 can be straightened or otherwise deformed through the application of force, then return to its pre-formed shape by virtue of the super-elasticity ofshape wire48 after the removal of the deforming force. For example,distal tip assembly40 can be straightened by manual force and inserted to the heart through an introducer. The introducer can maintain the deforming (straightening) force asdevice10 is advanced through the introducer. Asdistal tip assembly40 emerges from the introducer into the heart, it would return to the pre-formed lariat shape ofshape wire48. In a shape memory embodiment,shape wire48 can have a “naturally” straight shape but form a pre-determined shape (such as the lariat shape of distal tip assembly40) upon exposure to an increased temperature (such as in the human body). Althoughshape wire48 is shown with a distal portion that forms a lariat shape,shape wire48 can be used to form a variety of shapes within the scope and spirit of the present invention. Additionally,shape wire48 can also be configured as a pull wire, such that the application of force at the proximal end of device10 (such as pulling on wire48) can alter the shape ofdistal tip assembly40. For example, pulling onshape wire48 can decrease the radius of the lariat shape.
• One method of addingtip electrode46 andshape wire48 todevice10 is topre-couple shape wire48 withtip electrode46, thenthread shape wire48 throughlumen44. In doing so,shaft42 and one or more position sensors—shown in outline form as26₁and26₂although withinwall50 ofshaft42—must be guided over the curvature ofshape wire48.Shape wire48 can include one or more sharp bends, such asbend52, that can place a large amount of stress onshaft42 and any components disposed withinwall50. However, becausesensors26₁,26₂are withinsleeves28 instead of embedded directly inwall50,sensors26₁,26₂can shift and move relative to the portion ofwall50 surrounding eachsensor26, thereby reducing or eliminating the direct mechanical stress transmitted throughwall50 that would otherwise be imparted to eachsensor26. In other words, eachsensor26 is tethered withinwall50, rather than rigidly embedded inwall50. Thus, eachsensor26 can be guided overbend52 and other stress-inducing portions ofshape wire48 without breaking. Even though eachsensor26 can shift relative to the portion ofwall50 surrounding thesensor26,sleeve28 andwiring36 ensure that each sensor remains in a predictable location for position sensing and navigation purposes.
• FIG. 10 is a cross-sectional view of the extreme distal end ofdistal tip assembly40, taken substantially along line10-10 inFIG. 9.Tip electrode42 can be coupled to the extreme distal tip ofshaft42 through methods known in the art.Shape wire48 can be coupled to an inner surface oftip electrode46 through a metallurgical process such as soldering, brazing, welding, or another process known in the art.Shape wire48 can have a circular radial cross-section, or can have a different cross-section as needed for specific applications. Althoughtip assembly40 has only oneshape wire48, more than oneshape wire48 can be used. Each wire used can serve as either a shape wire having a pre-determined shape, as a pull wire, or as both. For example,device10 can incorporate only a single shape/pull wire48 as shown inFIG. 10, or can have multiple shape and pull wires. A more detailed explanation of shape wires and of joining a shape wire to a tip electrode can be found in commonly-owned U.S. Pat. No. 7,706,891, entitled “Catheter Employing Shape Memory Alloy Shaping Wire or Pull Wire and Method of Its Manufacture,” hereby incorporated by reference in its entirety.
• FIG. 11 is an isometric view of elongatemedical device10 having completeddistal tip assembly40.Distal end portion54 has a lariat shape according to the curvature ofshape wire48. After couplingtip electrode46 andshape wire48 withassembly40,assembly40 can be completed by various other steps known in the art or by adding other features known in the art, such as additional wiring, layers, or one or more additional electrodes. For example, in addition totip electrode46,distal end portion54 can include9 band electrodes (“decapolar” catheter) or19 band electrodes (“duo-decapolar” catheter). Aproximal end portion56 ofdevice10 can provide the ability to connectdevice10 to navigation and mapping systems and power sources, as well as the ability to manipulatedistal end portion54 ofdevice10.
• In an exemplary embodiment ofdistal tip assembly40,shaft42 can have a desired inner diameter (ID) of about 0.048 inches and a desired outer diameter (OD) of about 0.065 inches. In such an exemplary embodiment, first shaft layer segment22₁can have an ID of about 0.048 inches and an OD of about 0.050 inches.Sensor assembly24 can have an OD of about 0.013 inches. First shaft layer segments22₂and22₃can each have an ID of about 0.048 inches and an OD of about 0.052 inches.Second shaft layer38 can have an ID of about 0.058 inches and an OD of about 0.062 inches. First shaft layer22 andsecond shaft layer38 can both be PEBAX® material with a 55D durometer. After reflow lamination, the exemplary embodiment can have the desired ID, desired OD, and havesensor26 tethered withinwall50.
• Manufacturingdistal tip assembly40,distal end portion54, anddevice10 according to the methods described in conjunction withFIGS. 2-11 presents many advantages.Electromagnetic position sensor26 is disposed withinsleeve28 such thatsensor26 can shift relative tosleeve28. Accordingly,sensor26 is not subjected to all of the stress placed onwall50 asshaft42 is threaded overshape wire48. But becauseouter sleeve28—which containssensor26—is at least in part embedded in or otherwise substantially fixed to wall50, the shifting and movement ofsensor26 relative to wall50 can remain within a certain tolerance such thatsensor26 can still reliably be used for position sensing and device navigation. As a result, one ormore position sensors26 can be incorporated into a medical device with ashape wire48 of many different shapes, such as a lariat shape in its distal end portion.
• It should be understood that the embodiments ofdevice10,distal tip assembly40, anddistal end portion54 are exemplary in nature. Variations could be made and still fall within the spirit and scope of the claimed invention. For example,distal tip assembly40 can have one, two, three, ormore position sensors26 orposition sensor assemblies24.Multiple sensors26 orsensor assemblies24 can require more first shaft layer segments22₁. . .22_nthan specified in the embodiments herein. The lengths and thicknesses of shaft layers22,38 can be configured for specific devices and applications. Similarly, the durometer of shaft layers22,38 can be tailored to a specific application and the durometer of shaft42 (and/or the entire shaft of the finished device) can vary over its length.Lumen44 can be larger or smaller than the embodiments described herein depending on the required dimensions and features of a particular device. Other modifications and additions known in the art can also be possible.
• FIG. 12 is a side view of adistal end portion58 of asecond embodiment60 of an elongate medical device, with a portion of the outer jacket cut away to show interior components.Device60 includes a first embodiment of aflex circuit62 for connectingwiring36 tosensor26.Wiring36 can have leads64, consisting of a first free end and a second free end. Sensor leads34 can also consist of a first free end and a second free end.Flex circuit62 can electrically connect the first free end of wiring leads64 to the first free end of sensor leads34 to form a first electrical path and the second free end of wiring leads64 to the second free end of sensor leads34 to form a second electrical path while electrically separating the first and second electrical paths.Circuit62 can have a size and shape appropriate for the needed application.Flex circuit62can abut sensor26 on one axial end (the distal end ofcircuit62 in device60) and can abut wiring36 on the other axial end (the proximal end ofcircuit62 in device60). Ifwiring36 has a shielding, housing, or other outer layer, as shown,flex circuit62 can extend up to the outer layer or can extend partially into or adjacent to the outer layer.
• FIG. 13 is a cross-sectional view ofcatheter60, taken substantially along line13-13 inFIG. 12. As indevice10,sensor26 incatheter60 can be an electromagnetic coil sensor, including atubular core30 and acoil32 wrapped aroundcore30.Flex circuit62 can have abend66 to create contact surfaces in separate planes. A contact surface can have a greater radial dimension than axial dimension (“radial contact pad”), or a greater axial dimension than radial dimension (“axial contact pad”). Wiring leads64 and sensor leads34 can be coupled tocircuit62 through soldering or another electrically-conductive coupling method.
• FIGS. 14-17 are various isometric and plan views offlex circuit62.Circuit62 can include an electrically-insulative substrate78 and two sets ofcontact pads68,70 electrically connected by thin, electrically-conductive traces72. Contactpads68,70 can be made of an electrically-conductive material that can easily be coupled with wiring leads64 and sensor leads34, such as solder.Traces72 can be an electrically-conductive material, such as brass. Contactpads68 can be axial contact pads and can be provided at the proximal end ofcircuit62 for connection with wiring leads64. Contactpads70 can be radial contact pads and can be provided at the distal end ofcircuit62 for connection with sensor leads34.Substrate78 can also have anaxial extension portion74 extending axially fromcontact pads68.Axial extension portion74 can have a length similar or substantially equal to the length of associated leads, such as wiring leads64. In an exemplary embodiment, axial length L₄offlex circuit62 can be about 0.038 inches, length L₅of the contact portion (i.e. , the portion ofcircuit62 includingcontact pads68,70, and traces72) ofcircuit72 can be about 0.020 inches, and length L₆ofaxial extension portion74 can be about 0.018 inches.
• FIGS. 18-19 are plan views of asecond embodiment76 of a flex circuit.Circuit76 performs the same functions ascircuit62 as described above, except where otherwise noted, but is slightly different in form.Circuit76 can includesubstrate78 and two pairs or sets ofcontact pads68,70, both of which are axial contact pads. Contactpads68,70 can be joined by axially-extending electrically-conductive traces72.Substrate78 can also include twoaxial extension portions74₁,74₂(one at the proximal end ofcircuit76 and one at the distal end).Circuit76 can be used instead ofcircuit62 when two axial extension portions are desired, or when two sets of axial contact pads are desired.
• In an embodiment ofcircuit76, axial length L₇ofcircuit76 can be about 0.072 inches. Length L₈of the contact portion ofcircuit76 can be about 0.032 inches. Contactpads68 can have an axial length of about 0.010 inches, andcontact pads70 an axial length of about 0.004 inches.Traces72 can have an axial length of about 0.0158 inches. Contactpads68,70, and traces72 can each have a width of about 0.002 inches.
• Although only shown specifically withdevice60, a flex circuit such asflex circuit62 orflex circuit76 can find use with any device for which electrical coupling between two sets of leads is desirable. For example,flex circuit62 or76 can be used in conjunction with elongatemedical device10 as an interface to couplesensor26 withwiring36.
• Although numerous embodiments of this invention have been described above with a certain degree of particularity, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of this invention. All directional references (e.g., plus, minus, upper, lower, upward, downward, left, right, leftward, rightward, top, bottom, above, below, vertical, horizontal, clockwise, and counterclockwise) are only used for identification purposes to aid the reader's understanding of the present invention, and do not create limitations, particularly as to the position, orientation, or use of the invention. Joinder references (e.g., attached, coupled, connected, and the like) are to be construed broadly and can include intermediate members between a connection of elements and relative movement between elements. As such, joinder references do not necessarily infer that two elements are directly connected and in fixed relation to each other. It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not limiting. Changes in detail or structure can be made without departing from the spirit of the invention as defined in the appended claims.

Claims (20)

1.-20. (canceled)

21. A method of fabricating a distal tip assembly for an elongate medical device having an axis, comprising:

placing a sensor within an outer sleeve to form a sensor assembly;

placing said sensor assembly on a first shaft layer at a distal end portion of said elongate medical device;

applying a second shaft layer radially outward of said sensor assembly and said first shaft layer; and

subjecting said tip assembly to a reflow lamination process, wherein said first shaft layer and said second shaft layer bond to an outer surface of said outer sleeve.

22. The method ofclaim 21, further comprising:

coupling a tip electrode to an extreme distal end of said distal end portion;

placing a shape wire radially-inward of said first shaft layer;

coupling said shaft wire to said tip electrode.

23. The method ofclaim 22, wherein said shape wire defines a lariat shape.

24. The method ofclaim 22, wherein said the shape wire is Nitinol.

25. The method ofclaim 21, wherein said outer sleeve comprises expanded polytetrafluoroethylene (ePTFE).

26. The method ofclaim 21, wherein said sensor comprises a tubular core and an electrically-conductive coil wound on said core.

27. An elongate medical device comprising:

a shaft having an exterior wall and defining an axis;

an inner structure within the shaft; and

a first sensor disposed on the inner structure, wherein the first sensor is positioned between the inner structure and the exterior wall and in contact with the exterior wall, wherein the inner structure is bonded to an inner surface of the exterior wall.

28. The elongate medical device ofclaim 27, wherein, said exterior wall comprises expanded polytetrafluoroethylene (ePTFE).

29. The elongate medical device ofclaim 27, wherein said first sensor comprises a tubular core and an electrically-conductive coil wound on said core, said core defining a second axis.

30. The elongate medical device ofclaim 27, further comprising a tip electrode coupled to a distal end portion of the shaft.

31. The elongate medical device ofclaim 27, wherein the bond between the inner structure and the inner surface of the exterior wall is formed from a reflowed material.

32. The elongate medical device ofclaim 27, wherein the inner structure is bonded to an inner surface of the exterior wall at a portion of the inner structure that is proximate the first sensor.

33. The elongate medical device ofclaim 27, further comprising a second sensor, wherein the second sensor is located at a different location along a longitudinal axis of the elongate medical device.

34. The elongated medical device ofclaim 33, further comprising a distal tip assembly comprising the first sensor and the second sensor.

35. The elongate medical device ofclaim 34, wherein the distal tip assembly is formed in a curved shape.

36. An elongate medical device comprising:

a first sensor disposed on an inner structure, wherein the first sensor is positioned between the inner structure and an exterior wall and the first sensor is in contact with the exterior wall; and

a second sensor disposed on the inner structure, wherein the second sensor is positioned between the inner structure and the exterior wall and the second sensor is in contact with the exterior wall.

37. The elongate medical device ofclaim 36, wherein the first sensor is located at a different longitudinal position along a longitudinal axis of the elongate medical device.

38. The elongate medical device ofclaim 37, wherein the elongate medical device further comprises a distal tip assembly comprising the first sensor and the second sensor.

39. The elongate medical device ofclaim 38, wherein the distal tip assembly is formed in a curved shape.

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