Sensing and mapping catheter for guiding and supporting a balloon catheter

Abstract

The invention is entitled "Sensing and mapping catheter for guiding and supporting balloon catheters". The invention discloses a catheter configured to guide and support balloon catheters for use in and around the pulmonary veins and their ostia, the catheter having an elongated shaft including a proximal portion having a first flexibility and a distal portion having a second flexibility greater than the first flexibility, and a distal assembly including an elbow portion and a generally circular portion generally transverse to the longitudinal axis, and the generally circular portion including a third flexibility greater than the second flexibility. A single axis position sensor and a sensing ring electrode are carried on the generally circular portion.

Description

TECHNICAL FIELD

[0001] The present invention relates to a catheter, particularly an electrophysiology catheter having a position sensor and an electrical sensor. BACKGROUND

[0002] Electrode catheters have been in common use in medical practice for many years. They are used to stimulate and map electrical activity in the heart, as well as to ablate sites of abnormal electrical activity. Atrial fibrillation is a common, persistent cardiac arrhythmia and is a major cause of stroke. The condition is perpetuated by reentrant wavelets that propagate in an abnormal atrial tissue substrate. Various approaches have been developed to interrupt the wavelets, including surgical or catheter-mediated atriotomy. Prior to treatment of the condition, it is necessary to first locate the wavelets. Various techniques have been proposed for making this determination, including the use of a catheter with a mapping assembly adapted to measure activity within a pulmonary vein, coronary sinus or other tubular structure relative to the inner perimeter of the structure. One such mapping assembly has a distal "lasso" structure including a generally circular main region transverse to and distal of the catheter body, wherein the tubular structure includes a non-conductive covering over at least the main region of the mapping assembly. A support member including a shape memory is provided within at least the circular main region of the mapping assembly. The generally circular main region of the mapping assembly carries a plurality of electrode pairs, each pair including two ring electrodes.

[0003] More recently, balloon catheters have been used to ablate the ostium of a pulmonary vein. The balloon, which has electrodes on its outer surface, is advanced into the left atrium where it is inflated and positioned to nestle in the ostium so as to make simultaneous circumferential tissue contact around the ostium. However, depending on the size of the balloon and ostium, the balloon can be dislodged from the ostium during the ablation procedure.

[0004] Applicants have recognized that there is a need to provide a catheter having a distal "lasso" assembly that can be used as a guide wire and support a balloon nested in an ostium, while also being able to sense electrical signals from tissue of the tubular region of the ostium and provide a position signal for 3-D mapping. SUMMARY

[0005] In some embodiments, an electrophysiology catheter includes an elongate shaft defining a longitudinal axis of the catheter, the shaft including a proximal portion having a first flexibility and a distal portion including a second flexibility greater than the first flexibility; a distal assembly including an elbow portion and a generally circular portion transverse to the longitudinal axis, the generally circular portion including a third flexibility greater than the second flexibility; a single-axis sensor located in the generally circular portion; and a ring electrode located on the generally circular portion.

[0006] In some embodiments, the elongated shaft includes a hypotube having a lumen.

[0007] In some embodiments, the hypotube is coextensive with the proximal portion of the shaft.

[0008] In some embodiments, the catheter includes a pre-shaped support member having shape memory, the pre-shaped support member extending at least through the distal assembly, wherein a distal end of the pre-shaped support member is received in the lumen of the hypotube.

[0009] In some embodiments, the catheter includes a pre-shaped support member having shape memory, the pre-shaped support member extending at least through the distal assembly.

[0010] In some embodiments, the pre-shaped support member includes a proximal portion extending through the shaft.

[0011] In some embodiments, the catheter includes a second support member proximal of the pre-shaped support member and extending through the shaft, the second support member including a distal end coupled to a proximal end of the pre-shaped support member.

[0012] In some embodiments, the proximal portion of the shaft includes a first diameter D1, the distal portion of the shaft includes a second diameter D2, and the substantially circular portion of the distal assembly includes a third diameter D3, and D1 > D2 > D3.

[0013] In some embodiments, the elbow portion of the distal assembly includes a transition portion, a proximal end of the transition portion configured to have the diameter D2, and a distal end thereof configured to have the diameter D3.

[0014] In some embodiments, D1 is in a range of about 0.030 inches to about 0.040 inches, D2 is in a range of about 0.018 inches to 0.011 inches, and D3 is about 0.011 inches.

[0015] In some embodiments, an electrophysiology catheter includes an elongated shaft defining a longitudinal axis of the catheter, the shaft including a proximal portion having a first flexibility and a distal portion including a second flexibility greater than the first flexibility; a distal assembly including an elbow portion and a substantially circular portion substantially transverse to the longitudinal axis, the substantially circular portion including a third flexibility greater than the second flexibility; a plurality of single-axis sensors located in the substantially circular portion; and a plurality of ring electrodes located on the substantially circular portion.

[0016] In some embodiments, the conduit includes an elongated support member with shape memory, the elongated support member extending co-existing with the distal portion of the shaft and with the distal assembly.

[0017] In some embodiments, the conduit includes a second support member that extends co-exists with the proximal portion of the shaft.

[0018] In some embodiments, the conduit includes a subcapsule that extends co-exists with the proximal portion of the axis.

[0019] In some embodiments, the elongated support member coexisting with the bend portion of the distal assembly includes a transition portion having a distal end with a smaller diameter and a proximal end with a larger diameter.

[0020] In some embodiments, the transition portion tapers from the proximal end having the larger diameter to the distal end having the smaller diameter.

[0021] In some embodiments, the proximal portion of the shaft has a first length, and the distal portion of the shaft has a second length less than the first length.

[0022] In some implementations, the generally circular portion is configured to make circumferential contact with tissue in the tubular region.

[0023] In some embodiments, the support member includes a linear portion located proximal to the generally circular portion and configured to support the balloon of the second catheter to contact the orifice of the pulmonary vein.

[0024] In some embodiments, the support member includes a generally linear portion located proximal to the generally circular portion, and the generally linear portion is configured to support a balloon of the second catheter to contact the orifice of the pulmonary vein, while the generally circular portion is in circumferential contact with tissue in the pulmonary vein. Attached Figure Description

[0025] These and other features and advantages of the invention will be better understood when considered in conjunction with the accompanying drawings and by referring to the following detailed description. It should be understood that some selected structures and features are not shown in certain drawings to provide a better view of the remaining structures and features.

[0026] Figure 1 A perspective view of the catheter of this disclosure according to one embodiment of a support balloon catheter.

[0027] Figure 2 An end perspective view of a preformed support member assembled according to one embodiment of a distal "lasso" assembly.

[0028] Figure 3 Side perspective view of a distal "lasso" assembly positioned in a pulmonary vein while supporting a balloon nested in the ostium of the pulmonary vein.

[0029] Figure 4 Side cross-sectional view of a distal assembly including an elbow segment according to one embodiment.

[0030] Figure 5A End cross-sectional view of the distal assembly of Figure 4

[0031] Figure 5B End cross-sectional view of the distal assembly of Figure 4

[0032] Figure 6 Side cross-sectional view of a distal assembly including a generally circular segment according to one embodiment.

[0033] Figure 7 Side cross-sectional view of a shaft including a second support member according to one embodiment.

[0034] Figure 8 Side cross-sectional view of a shaft and distal assembly including a hypotube according to another embodiment.

[0035] Figure 9 Side view of a hypotube according to another embodiment. DETAILED DESCRIPTION

[0036] The following detailed description should be read with reference to the drawings, in which like elements in different drawings are identically numbered. The drawings, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of the application. The detailed description illustrates by way of example, not by way of limitation, the principles of the application. This description will clearly enable one skilled in the art to make and use the application, and describes several embodiments, adaptations, variations, alternatives, and uses of the same, including what is presently believed to be the best way to implement the application.

[0037] As used herein, the term "about" or "approximately," with reference to any numerical or range of numbers, indicates that suitable dimensional tolerances are permitted which allow the components or elements to function as intended as described herein. More specifically, "about" or "approximately" can refer to a range of values ±20% of the recited value, for example "about 90%" can refer to a range of values of 71% to 99%. Additionally, as used herein, the terms "patient," "host," "user," and "subject" refer to any human or animal subject and are not intended to limit the systems or methods to human use, although use of the subject application in human patients is a preferred embodiment. ​​

[0038] Reference is made to Figure 1 and Figure 2 The embodiments disclosed herein include a catheter 10 configured for use with a balloon catheter 100 that includes an elongated support shaft 12 and a 3-D distal or "lasso" assembly 15. The distal assembly 15 carries one or more single axis sensors ("SAS") 13 configured to respond to an external magnetic field generator (not shown) to produce signals indicative of the position of the distal assembly 15, and one or more ring electrodes 11 configured to sense electrical signals from tissue. The distal assembly 15 includes a pre-shaped support member 16 of shape memory, e.g., nitinol wire, that provides a 3-D or ring configuration to the distal assembly 15. In this regard, it will be appreciated that in describing the distal assembly 15, the shape memory elongated support member 16 includes portions that impart a corresponding segment of the distal assembly 15 with a shape, including a curved portion 16C corresponding to a curved segment 15C of the distal assembly 15 and an elbow portion 16E located proximal of the curved portion 16C corresponding to an elbow segment 15E of the distal assembly 15. In some embodiments, the curved (e.g., circular, helical or annular, all terms used herein interchangeably) portion 16C of the support member 16 is generally transverse to the shaft 12 defining a longitudinal axis L of the catheter, and the curved portion 16C has a curved arc or length spanning at least 360 degrees, if not about 450 degrees, with a distally overlapping tail portion 16T. Further, the curved portion 16C is configured relative to the shaft 12 such that the longitudinal axis L defined by the shaft 12 intersects the curved portion 16C and is offset from the center of the circle generally defined by the curved portion 16C.

[0039] The elongated support shaft 12 of the catheter has a proximal portion 12P of lesser flexibility and a distal portion 12D of greater flexibility. The shaft 12 is configured to pass through the lumen of the balloon catheter 14 and to properly support the balloon 140 in the ostium 110 of the pulmonary vein 130, as shown in Figure 3 , with the distal lasso assembly 15 extending into the pulmonary vein for circumferential contact with the tubular tissue of the pulmonary vein. Advantageously, the proximal portion 12P of the shaft is configured to have sufficient rigidity to transmit axial thrust and torque applied by the user, e.g., at the proximal end of the shaft 12 manipulating the connector handle 27 Figure 1 and the torque device 17 Figure 1 mounted on the proximal portion 12P, while the distal portion 12D of the shaft is configured to have sufficient flexibility to accommodate the indirect access angle between the distal lasso assembly 15 and the ostium 110 in which the supported balloon 140 is located.

[0040] In some embodiments, as shown in Figure 1 and Figure 2As shown, the shape memory support member 16 of the distal assembly 15 has an elongated form having sufficient length to extend through the entirety of the distal assembly 15 and the associated shaft 12. As such, the elongated support member 16 includes the following portions:

[0041] (i) a longer, generally linear proximal portion 16P having a first diameter D1 and spanning the length of the proximal portion 12P of the shaft 12;

[0042] (ii) a shorter, generally linear distal portion 16D having a second diameter D2 and spanning the length of the distal portion 12D of the shaft 12;

[0043] (iii) a distal curved portion 16C having a third diameter D3 and spanning the curved distal portion 15C of the distal assembly 15; and

[0044] (iv) a relatively short elbow portion 16E having a transition diameter DT in the range of D2 to D3 and spanning the elbow segment 15E extending between the generally linear distal portion 16D and the distal curved portion 16C of the support member 16;

[0045] wherein diameter D1 > diameter D2 > diameter D3, such that the proximal portion 16P has the least flexibility, the distal portion 16D has greater flexibility, and the distal curved portion 16C has the greatest flexibility. In some embodiments, diameter D1 is about 0.030 inches, diameter D2 is about 0.014 inches to 0.018 inches, and diameter D3 is about 0.011 inches. Between the proximal portion 16P and the distal portion 16D, the diameter of the wire 16 can step transition or gradually transition between diameters D1 and D2 as desired or appropriate. Between the distal portion 16D and the curved portion 16C, the elbow portion 16E is configured to gradually transition between diameters D2 and D3. In some embodiments, the gradual transition between diameters D2 and D3 occurs over a span of about 2 mm in the elbow portion 16E. The length of the proximal portion 16P of the support member 16 is not critical. However, in some embodiments, the length of the distal portion 16D is at least the longitudinal length of the balloon 140, so that it can accommodate the balloon when the balloon is supported. In some embodiments, the length of the shaft 12 is about 2 meters, with the length of the distal portion 12D (which has greater flexibility relative to the proximal portion 12P) being between about 6 cm to 8 cm.

[0046] Referring to Figure 2 and Figure 4The distal bend 16C of the shape memory support member 16 carries one or more SAS. It should be understood that each SAS 13 has a corresponding wire coil sensor 50 and cable 20, wherein the wire coil sensor 50 is wound around a selected location on the distal bend 16C, and the cable 20 includes a pair of dedicated wires 21, 21', which, together with shielding fiber 23, are encased within an insulating sheath 22 that generally co-extends with the wires 21, 21'. For the sake of simplicity provided herein, the wires 21, 21' of all SAS 13 carried on the distal assembly 15 are shown herein as passing through a common insulating sheath 22 having a common shielding fiber 23, thus forming a single cable 20 for all SAS 13.

[0047] exist Figure 2 In the illustrated embodiment, the distal assembly 15 carries three SAS, namely the proximal SAS 13A, the intermediate SAS 13B, and the distal SAS 13C, comprising three wire coils 50A, 50B, and 50C, referred herein as the proximal coil, the intermediate coil, and the distal coil, respectively. These three wire coils are arranged in equiangular positions around the bend 16C, for example at approximately 0 degrees, 120 degrees, and 240 degrees. The wire coil 50 of each SAS is connected to a pair of dedicated wires 21 and 21′, wherein wire 21 is connected to the distal end of the wire coil 50, and wire 21′ is connected to the proximal end of the wire coil 50. Therefore, in the illustrated embodiment, the distal coil 50C ( Figure 6 (Best shown in the diagram) Connected to wire pairs 21C and 21C′, intermediate coil 50B connected to wire pairs 21B and 21B′, and proximal coil 50A connected to wire pairs 21A and 21A′. To assemble SAS 13A, SAS 13B, and SAS 13C onto the curved portion 16C of the preformed support member 16, in some embodiments, a method of manufacturing or assembling the preformed support member having SAS includes: (i) winding wire coil 50C around the preformed support member 16 at position 240 degrees to form SAS 13C, (ii) connecting wire pairs 21C and 21C′ to the distal and proximal ends of wire coil 50C, respectively, and (iii) winding wire pairs 21C and 21C′ around the curved portion 16C in the proximal direction. Different winding methods can be used during the use of the conduit to mitigate strain and prevent wire breakage.

[0048] The assembly method further includes: (iv) wrapping wire pairs 21C and 21C' at position 120 degrees, (v) wrapping wire coil 50B over the wrapped wire pairs 21C and 21C' to form SAS 13B, (vi) connecting wire pairs 21B and 21B' to the distal and proximal ends of coil 50B, respectively, and (vi) wrapping wire pairs 21C and 21C' and 21B and 21B' around bend portion 16D in the proximal direction.

[0049] The assembly method further includes: (vii) wrapping wire pairs 21C and 21C' and 21B and 21B' at position 0 degrees, (viii) wrapping wire coil 50A over the wrapped wire pairs 21C and 21C' and 21B and 21B' to form SAS 13A, (ix) connecting wire pairs 21A and 21A' to the distal and proximal ends of coil 50A, respectively, and (x) wrapping wire pairs 21C and 21C', 21B and 21B', and 21A and 21A' around bend portion 16C in the proximal direction. It will be appreciated that one or more heat shrink sleeves can be positioned over the wrapped wire pairs between the formed SAS and the adjacent SAS.

[0050] It will also be appreciated that the order of the above actions or the direction of the wrapping (e.g., distal to proximal or proximal to distal) can be changed as needed or appropriate, and that heat shrink sleeves can be placed over the wrapped wire pairs under each SAS, wire coil, or wire coil as needed or appropriate. In any case, distal SAS 13C includes a wire coil 50C having a distal end connected to wire 21C and a proximal end connected to wire 21C', intermediate SAS 13B includes a wire coil 50B having a distal end connected to wire 21B and a proximal end connected to wire 21B', where wire coil 50B is wrapped over wires 21C and 21C', and proximal SAS 13A includes a wire coil 50A having a distal end connected to wire 21A and a proximal end connected to wire 21A', where wire coil 50A is wrapped over wires 21C and 21C' and 21B and 21B'.

[0051] At elbow portion 16E, cable 20 housing wire pairs 21 (e.g., 21A, 21A', 21B, 21B', 21C, and 21C') is advantageously located on the inner surface 52 of elbow portion 16E (facing inward toward the curvature) to minimize the outer diameter of distal assembly 15 in this region, as Figure 4 、 Figure 5A and Figure 5Bbetter shown. In this regard, the distal end of the cable 20's insulating jacket 22 and the shield fiber 23 therein are cut or otherwise terminated proximal of the elbow portion 16E, thereby exposing the plurality of wire pairs 21. Further, all of the wires 21 are spread out or fanned out, placed against the inner surface 52, and secured by adhesive 37 Figure 5B ), to minimize the circumferential size and profile of the distal assembly 15 at its elbow portion 15E. Distal end portions of the shield fiber 23 can be wrapped around the wires 21 and the pre-shaped support member 16 Figure 4 ), to encircle them, thereby forming a tighter profile around the pre-shaped support member 16. A heat shrink sleeve 38 can extend over the cable 20 and shield fiber 23 proximal of the elbow portion 16E and the exposed wires 21 and safety fiber 25 in the elbow portion 16E, as appropriate or suitable. The proximal and terminal ends of the heat shrink sleeve can be located at any location along the support member 16, as desired or suitable.

[0052] Thus, a method of assembling a pre-shaped support member 16 having a SAS includes: (i) preparing a cable 20 for securing to an elbow portion 16E; and (ii) securing the prepared cable to the elbow portion, wherein preparing the cable includes: (a) cutting or terminating a distal end of an outer insulating jacket 22 substantially proximal of the elbow portion; (b) exposing wires 21 in the cable; (c) spreading out or fanning out the exposed wires 21, and wherein securing the prepared cable includes: (a) placing the fanned out exposed wires on an inner surface 52 of the elbow portion; (b) applying adhesive to the fanned out exposed wires 21 on the inner surface of the elbow portion; and (c) covering the secured exposed wires and at least a distal portion of the insulating jacket 22 with a heat shrink sleeve 38. Preparing the cable can further include cutting or terminating a distal end of a shield fiber 23 and wrapping the distal end around the exposed wires 21 and the pre-shaped support member 16. Securing the prepared cable can further include covering a plurality of safety strands 25 (e.g., VECTRAN strands) whose proximal ends are anchored to the shaft 12 and whose lengths are coextensive with the wires 21 under the heat shrink sleeve 38, to tether the distal assembly 15 to the shaft 12 as a safety measure to prevent the distal assembly 15 from coming off. Distal ends of the safety strands 25 can be anchored to a distal end of the pre-shaped support member 16. A description of a suitable SAS is provided in U.S. Patent 8,792,962, the entirety of which is hereby incorporated by reference.

[0053] As previously mentioned, the distal assembly 15 not only carries one or more SAS 13, but also carries one or more ring electrodes 11. As Figure 6As shown, the distal assembly 15 includes an outer braided tube 40 having ring electrodes 11 and conductive leads 41. Although the tube 40 has an inner lumen 39, the conductive leads 41 are embedded in the sidewall 42 as part of the extrusion manufacturing process of the tube 40, as will be appreciated by those of ordinary skill in the art. In some embodiments, the outer braided tube 40 covers the entire length of the pre-shaped support member 16, including the proximal portion 16P, the distal portion 16D, the elbow portion 16E, and the curved portion 16C. In the portion of the braided tube 40 that covers the curved portion 16C, the ring electrodes 11 carried thereon are formed by selectively removing (e.g., laser cutting the outer sidewall 42) to form recesses 44 at predetermined locations so as to expose selected individual leads 41. Then, a conductive epoxy 43, such as a platinum conductive epoxy or a gold conductive epoxy, is applied to fill the recesses 44 and also to wrap around the outside of the sidewall 42 along the circumference at the recesses to form respective ring electrodes 11 at each predetermined location. Thus, one method of constructing the outer tube 40 with ring electrodes 11 and embedded leads 41 includes: (i) extruding a tube 40 having leads 41 embedded in a sidewall 42, wherein the tube has an outer surface and an inner surface defining an inner lumen; (ii) removing a portion of the sidewall from the outer surface to expose the leads 41 within recesses; (iii) applying a conductive epoxy to fill the recesses and applying a corresponding circumferential band around the recesses to form the ring electrodes 11. The extrusion of the tube 40 with leads 41 can be accomplished with a conventional lead extruder. The braided wires 41 embedded in the sidewall 42 of the tube 40 can extend distally of their respective ring electrodes without any adverse effect on the functionality of the ring electrodes.

[0054] After the outer tube 40 with ring electrodes 11 and embedded leads 41 has been constructed, the outer tube 40 can be slid onto the assembled distal assembly 15. In some embodiments, one assembly method includes: (i) the above-described method of manufacturing or constructing the outer tube 40 with ring electrodes 11 and embedded leads 41; (ii) the above-described method of assembling the pre-shaped support member 16 with the SAS 13; and (iii) installing the constructed outer tube 40 onto the pre-shaped support member 16 with the SAS 13. The installation can be accomplished by inserting the assembled pre-shaped support member 16 into the inner lumen 39 of the constructed outer tube 40. In this way, the construction of the catheter 10 is simplified by separating the construction of the outer tube 40 providing the ring electrodes from the construction of the underlying support member 16 carrying the SAS. The distal ends of the outer tube 40 and the support structure 16 can be collectively plugged and sealed with a sealant ball, such as a polyurethane, to form an atraumatic ball-shaped distal end of the catheter 10.

[0055] At the proximal end of the outer tube 40 that terminates near or in the connector handle 27, the proximal portion of the wire 41 can be exposed from the tube 40 by selectively removing the sidewall 42 for connection to appropriate electrical terminals in the connector handle 27 when transmitting the sensed electrical signals to an electrophysiology station for processing as known in the art. The cable 20, including the wire pairs 21, 21' of each SAS carried on the distal assembly 15, extends through the lumen 39 of the outer tube 40, is coextensive with the distal portion 16D and the proximal portion 16P of the support member 16, through the shaft 12 of the catheter and into the connector handle 27 for transmission of the position signals to an electrophysiology station for processing as known in the art.

[0056] In alternative embodiments, the shorter support member 16 is without a proximal portion 16P and has a proximal end that terminates at a suitable location proximal of the distal portion 16D and the elbow portion 16E. As shown, the shorter support member 16 has a proximal end 16PE, for example, at about 8.0 cm proximal of the elbow portion 16E and is connected to a second support member 30, for example, a metal wire or a stainless steel wire, via a lumen coupler 31 that extends proximally toward the connector handle 12, where 8.0 cm is selected based on the longitudinal length of the balloon 140 supported on the distal linear portion 12D of the shaft 12 when the distal assembly 15 is located within the tubular region 120 of the mouth 110 on which the balloon 140 rests on the distal surface of the balloon. Figure 7 Figure 3 The outer tube 40 with the ring electrode 11 and the embedded wire 41 extends over the support member 16 and the second support member 30, thereby covering the entirety of the distal assembly 15 and the shaft 12. The SAS cable 20 is coextensive with the support member 16 in the distal shaft portion 12D and with the second support member 30 in the proximal shaft portion 12P in the lumen 39 of the tube 40 and can be external to the coupler 31. To provide different flexibility in the shaft 12 and the distal assembly 15, the second support member 30 has a diameter D1, the distal portion 16D of the support member 16 has a diameter D2, and the curved portion 16C of the support member 16 has a diameter D3, where D1 > D2 > D3, such that the second support member 30 has the least flexibility, the distal portion 16D has greater flexibility, and the curved portion 16C has the most flexibility. Likewise, the elbow portion 16E provides a gradual transition in diameter from D2 to D3, but there can be a stepped transition between the diameter D1 of the second support member 30 and D2 of the distal portion 16D at the coupler 31.

[0057] In other alternative embodiments, as Figure 8 ​As shown, the shorter support member 16 (without proximal portion 16P) has a proximal end received in the distal end of a lumen structure, such as a hypotube 16 having a lumen 28 that extends proximally toward a connector handle 27. The shorter support member 16 extends through an outer covering 32 of, for example, PELLETHANE, the lumen 36 of which receives the curved portion 16C and distal portion 16D of the SAS-carrying member 16, and the proximal end 32P of which abuts the distal end 18D of the hypotube 18. As will be understood by those of ordinary skill in the art, a conductive band 33 is mounted over the outer covering 32 to form the ring electrode 11 on the distal assembly 15. Leads 48 connected to the individual conductive bands 33 enter the lumen 36 via through-holes 34 formed in the sidewall 35 of the outer covering 32. Within the lumen 36, the leads 48 extend proximally with the cable 20 for the SAS in the distal assembly 15, and through the lumen 28 of the hypotube 18 toward the connector handle 27. In some embodiments, the outer diameter of the hypotube 18 is in the range of about 0.030 to 0.040 inches. As will be understood by those of ordinary skill in the art, the proximal end 32P of the outer covering 32 is crimped to the distal end 18D of the hypotube 18 to secure the proximal end 32P of the outer covering 32 to the distal end 18D of the hypotube 18. Figure 9 As shown, the distal portion of the hypotube 18 can be configured with one or more helical cuts 45 to increase flexibility.

[0058] In use, the catheter 10 is fed into and through the lumen 120 of the balloon catheter 100, where the lumen 120 extends through the shaft 130 of the balloon catheter and the balloon 140 itself. To feed the distal assembly 15, it is straightened so that the curved portion 15C enters the lumen 120 first, followed by the elbow portion 15E, and so on. The distal assembly 15 is advanced relative to the balloon catheter until the distal assembly 15 passes through the distal end of the balloon catheter, at which point the distal assembly 15 is free to assume a 3-D shape in the patient's left atrium in accordance with the pre-shaped shape memory support members 16 thereunder. The catheter 10 is then manipulated to insert the distal assembly 15 into a pulmonary vein, with the ring electrode 11 in contact with tissue along the inner circumference of the tubular region of the pulmonary vein. Using the shaft 12 (and particularly the distal portion 12D) as a guide wire, the balloon catheter 100 is then advanced toward the ostium of the pulmonary vein until the distal surface of the balloon is in contact with the ostium. The shaft 12 of the catheter 10 has a proximal portion 12P that is less flexible so as to serve as a guide wire for the balloon catheter 100, and a distal portion 12D that is more flexible so as to allow for flexing in the event that the approach angle of the distal assembly 15 is not aligned with the center of the ostium, and yet has sufficient stiffness to properly support the balloon thereon. One or more of the SAS 13 in the distal assembly 15 respond to an external magnetic field generator, typically located below the patient's bed, to provide a position signal, and the ring electrode 11 carried on the distal assembly 15 senses electrical signals from the tissue of the pulmonary vein, including electrical signals to assess whether PV isolation has been achieved by ablation of the tissue at or adjacent to the ostium.

[0059] The foregoing description has been presented with reference to presently preferred embodiments of the application. Persons skilled in the art and technology to which this application pertains will appreciate that alterations and modifications can be made to the described structures without departing from the principles, spirit, and scope of the application. Any feature or structure disclosed in one embodiment can be incorporated into any other embodiment as needed or appropriate to replace or supplement other features. It should be understood that features of the application can be applied to increase linear movement of pull wires, shrink wires, or any other object in a medical device that requires insertion, removal, or tensioning, including the disclosed electrophysiology catheters. The drawings are not necessarily to scale as understood by one of ordinary skill in the art. Accordingly, the above detailed description is not to be interpreted in a limiting sense as the specific structure herein illustrated and described is merely intended to illustrate the principles of the application and not to limit the scope thereof as defined in the following claims and supported by the following claims.

Claims

1. An electrophysiology catheter, comprising: an elongated shaft defining a longitudinal axis of the catheter, the shaft including a proximal portion having a first flexibility and a distal portion including a second flexibility greater than the first flexibility; a distal assembly including an elbow portion and a generally circular portion generally transverse to the longitudinal axis, the generally circular portion including a third flexibility greater than the second flexibility; a single-axis sensor located in the generally circular portion; a ring electrode located on the generally circular portion; and an elongated support member having shape memory, the elongated support member coextensive with the distal portion of the shaft and coextensive with the distal assembly; wherein the elongated support member coextensive with the elbow portion of the distal assembly includes a transition portion having a distal end having a smaller diameter and a proximal end having a larger diameter; and wherein the transition portion tapers from the proximal end having the larger diameter to the distal end having the smaller diameter.

2. The catheter of claim 1, wherein the elongated shaft includes a hypotube having an internal lumen.

3. The catheter of claim 2, wherein the hypotube is coextensive with the proximal portion of the shaft.

4. The catheter of claim 3, wherein a distal end of the elongated support member is received in the internal lumen of the hypotube. the elongated support member extends at least through the distal assembly.

5. The catheter of claim 1, wherein, 6. The catheter of claim 5, wherein the elongated support member includes a proximal portion extending through the shaft.

7. The catheter of claim 5, further comprising a second support member located proximal of the elongated support member and extending through the shaft, the second support member including a distal end coupled to a proximal end of the elongated support member.

8. The catheter of claim 1, wherein the proximal portion of the shaft includes a first diameter Dl, the distal portion of the shaft includes a second diameter D2, and the generally circular portion of the distal assembly includes a third diameter D3, and D1 > D2 > D3.

9. The catheter of claim 8, wherein the elbow portion of the distal assembly includes the transition portion, a proximal end of the transition portion is configured to have the diameter D2, and a distal end of the transition portion is configured to have the diameter D3.

10. The catheter of claim 8, wherein Dl is in a range of 0.030 inches to 0.040 inches, D2 is in a range of 0.018 inches to 0.011 inches, and D3 is 0.011 inches.

11. An electrophysiology catheter, comprising: an elongated shaft defining a longitudinal axis of the catheter, the shaft including a proximal portion having a first flexibility and a distal portion including a second flexibility greater than the first flexibility; ​ a distal assembly comprising an elbow portion and a generally circular portion generally transverse to the longitudinal axis, the generally circular portion comprising a third flexibility greater than the second flexibility; a plurality of single-axis sensors located in the generally circular portion; a plurality of ring electrodes located on the generally circular portion; and an elongated support member having shape memory, the elongated support member coextensive with the distal portion of the shaft and coextensive with the distal assembly; wherein the elongated support member coextensive with the elbow portion of the distal assembly comprises a transition portion having a distal end with a smaller diameter and a proximal end with a larger diameter; and wherein the transition portion tapers from the proximal end having the larger diameter to the distal end having the smaller diameter.

12. The catheter of claim 11, further comprising a second support member coextensive with the proximal portion of the shaft.

13. The catheter of claim 11, further comprising a hypotube coextensive with the proximal portion of the shaft.

14. The catheter of claim 11, wherein the proximal portion of the shaft has a first length and the distal portion of the shaft has a second length less than the first length.

15. The catheter of claim 11, wherein the generally circular portion is configured for circumferential contact with tissue in a tubular region.

16. The catheter of claim 11, wherein the elongated support member comprises a linear portion proximal to the generally circular portion and configured to support a balloon of a second catheter for contact with an ostium of a pulmonary vein.

17. The catheter of claim 11, wherein the elongated support member comprises a generally linear portion proximal to the generally circular portion and configured to support a balloon of a second catheter for contact with an ostium of a pulmonary vein while the generally circular portion is in circumferential contact with tissue in the pulmonary vein. ​

Images