Force sensing catheter including sealed electrode tip assembly and method of assembling the same

Abstract

The present invention discloses an ablation catheter, which includes an irrigation conduit, a force sensor, an electrode tip assembly, a seal, and a temperature sensor. The irrigation conduit defines an irrigation lumen configured to deliver an irrigation fluid to the distal end of the ablation catheter. The force sensor includes a deformable body coupled to the irrigation conduit near the distal end of the irrigation conduit. The electrode tip assembly is coupled to the deformable body and extends distally therefrom, and defines an inner lumen in fluid communication with the irrigation lumen and an outer lumen receiving a distal portion of the deformable body. The seal is disposed between the electrode tip assembly and the deformable body and inhibits fluid flow between the inner lumen and the outer lumen. The temperature sensor is coupled to the electrode tip assembly and extends from the electrode tip assembly through the irrigation lumen.

Description

[0001] BACKGROUND OF THE DISCLOSURE

[0002] This application claims priority to U.S. Provisional Patent Application Serial No. 62 / 893,439, filed on August 29, 2019, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates generally to electrophysiology (EP) catheters. More particularly, the present disclosure relates to an ablation system including an EP catheter including a force sensor and a sealed electrode tip assembly that prevents irrigation fluid from interfering with the force sensor. Background Art

[0004] Electrophysiology catheters are used in an increasing number of medical procedures. For example, catheters are used in diagnostic, therapeutic, and ablation procedures. Typically, a catheter is manipulated through a patient's vasculature and reaches a predetermined site, such as a site within the patient's cardiovascular system, such as the heart or renal arteries.

[0005] The catheter may carry one or more electrodes that may be used for ablation, mapping, diagnosis, etc. Tissue ablation may be used to treat a variety of clinical conditions. For example, tissue ablation may be used to treat arrhythmias by destroying abnormal pathways that would otherwise conduct abnormal electrical signals to the myocardium. Several ablation techniques have been developed, including cryoablation, microwave ablation, radiofrequency (RF) ablation, and high-frequency ultrasound ablation.

[0006] Because RF ablation can generate a lot of heat, it may be necessary to monitor the temperature of the ablation assembly during the ablation procedure. The temperature of the ablation assembly can be monitored during the procedure using a thermocouple, which can sometimes be placed within the tip of one or more electrodes of the ablation assembly. Such thermocouples are typically routed from the outside of the ablation assembly to the inside and to the electrode tip for temperature measurement adjacent to the ablation site. Where a thermocouple is introduced into the ablation assembly, an adequate seal must be provided around the thermocouple.

[0007] It may also be desirable to include a mechanism for flushing certain target areas with a biocompatible fluid, such as saline solution. This flushing can reduce or avoid excessive or undesirable tissue damage, blood coagulation, and problems associated therewith. The ablation assembly may be provided with an external flushing port or an internal flushing lumen.

[0008] In addition, it may be necessary to monitor the contact between the ablation assembly and the tissue at the target site to ensure that the treatment is being effectively performed. Such contact can be monitored using a force sensor disposed within the ablation assembly. The force sensor can be an optical force sensor (e.g., a fiber optic force sensor). At least in some cases, fluid entering the force sensor may cause inaccurate force measurements. Sealing a force sensor in an ablation catheter that also includes a thermocouple and an irrigation line may present some challenges to the catheter design. For example, increasing the size of the force sensor to accommodate the seal will increase the strain on its optical fiber, resulting in inaccurate force readings or excessive stress on the optical fiber.

[0009] Therefore, there is a need for an improved ablation catheter assembly including a thermocouple and a force sensor with a suitable sealing mechanism. Summary of the invention

[0010] The present disclosure relates to an ablation catheter, which includes an irrigation conduit having a proximal end and a distal end, and defines an irrigation lumen, which is configured to deliver an irrigation fluid to the distal end of the ablation catheter. The ablation catheter also includes a force sensor and an electrode tip assembly, the force sensor including a deformable body coupled to the irrigation conduit near its distal end, and the electrode tip assembly is coupled to the deformable body and extends distally therefrom. The electrode tip assembly defines an inner cavity in fluid communication with the irrigation lumen and an outer cavity that receives a distal portion of the deformable body. The ablation catheter further includes a seal disposed between the electrode tip assembly and the deformable body. The seal inhibits fluid flow between the inner cavity and the outer cavity. The ablation catheter further includes a temperature sensor coupled to the electrode tip assembly and extending from the electrode tip assembly through the irrigation lumen.

[0011] The present disclosure also relates to a method for assembling an ablation catheter, the method comprising routing a temperature sensor through an irrigation lumen defined by an irrigation conduit such that the temperature sensor extends out of the distal end of the irrigation conduit. The method also comprises coupling a deformable body of the force sensor to the distal end of the irrigation conduit, positioning a seal near a distal portion of the deformable body, and routing the temperature sensor into an electrode tip assembly, the electrode tip assembly defining an inner cavity and an outer cavity. The method also comprises positioning a distal portion of the deformable body within an outer cavity of the electrode tip assembly, and coupling the electrode tip assembly to the deformable body such that the electrode tip assembly extends distally from the deformable body and the inner cavity is in fluid communication with the irrigation lumen. The seal is disposed between the electrode tip assembly and the deformable body to inhibit fluid flow between the inner cavity and the outer cavity. The method further comprises coupling the temperature sensor to the electrode tip assembly such that the temperature sensor extends from the electrode tip assembly through the irrigation lumen.

[0012] The present disclosure further relates to a catheter system including an ablation catheter and an ablation generator. The ablation catheter includes an irrigation conduit having a proximal end and a distal end and defining an irrigation lumen, which is configured to deliver an irrigation fluid to the distal end of the ablation catheter. The ablation catheter also includes a force sensor and an electrode tip assembly, the force sensor including a deformable body coupled to the irrigation conduit near its distal end, the electrode tip assembly coupled to the deformable body and extending distally therefrom. The electrode tip assembly defines an inner cavity in fluid communication with the irrigation lumen and an outer cavity receiving a distal portion of the deformable body. The ablation catheter further includes a seal disposed between the electrode tip assembly and the deformable body. The seal inhibits fluid flow between the inner cavity and the outer cavity. The ablation catheter further includes a temperature sensor coupled to the electrode tip assembly and extending from the electrode tip assembly through the irrigation lumen. The ablation generator is electrically coupled to the electrode tip assembly and configured to provide ablation energy thereto. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic block diagram of an ablation system.

[0014] Figure 2 Is suitable for Figure 1 A perspective view of an exemplary embodiment of an ablation catheter for use with an ablation system.

[0015] Figure 3 yes Figure 2 A cross-sectional view of the ablation catheter shown in FIG.

[0016] Figure 4 yes Figure 2 Cross-sectional view of the ablation catheter shown in .

[0017] Figure 5 yes Figure 2-4 A cross-sectional view of an electrode tip assembly of an ablation catheter is shown in FIG.

[0018] Figure 6 Is suitable for Figure 2-4 A cross-sectional view of another alternative electrode tip assembly for use with an ablation catheter is shown in FIG.

[0019] Figure 7 is a flow chart illustrating one embodiment of a method of assembling an ablation catheter. DETAILED DESCRIPTION

[0020] The present disclosure relates to ablation systems and methods of forming the same, and more particularly, to an ablation catheter including a force sensor and an electrode tip assembly sealed to the force sensor. Embodiments of the systems and methods disclosed herein facilitate providing an ablation catheter having a force sensor and a temperature sensor sealed from the electrode tip assembly, thereby facilitating monitoring of temperature and applied force during an ablation procedure. The temperature sensor is routed through an irrigation conduit to reduce the likelihood of leaks near the force sensor that may adversely affect force measurements. The arrangement enables a simpler and more reliable seal between the force sensor and the electrode tip assembly, and also enables a force sensor with a reduced diameter, which reduces the likelihood of the force sensor being subjected to excessive stress or strain during operation. The ablation catheter described herein also includes a fluid manifold configured to accommodate a temperature sensor and improve the dispersion of irrigation fluid through the electrode tip assembly. Embodiments of the ablation catheter described herein facilitate faster assembly, reduced number of parts, reduced component cost, and reduced assembly variability, which improves the overall reliability of the ablation catheter.

[0021] Now referring to the accompanying drawings, Figure 1 An exemplary embodiment of an ablation system 100 for performing one or more diagnostic and / or therapeutic functions is shown, including components for monitoring the temperature of an electrode before, during, and / or after performing an ablation procedure on a patient's tissue 102, and monitoring the contact force between the electrode and the tissue 102 before, during, and / or after the ablation procedure. In the illustrative embodiment, the tissue 102 is a heart or cardiac tissue. However, it should be understood that the system 100 is equally applicable to ablation procedures on other tissues and is not limited to ablation procedures on cardiac tissue.

[0022] The system 100 includes a medical device (such as a catheter 104), an ablation generator 106, one or more return patch electrodes 108 (also referred to as dispersive or neutral patch electrodes), and a control system 110 for communicating with and / or controlling one or more components of the ablation system 100. The control system 110 may include, for example, but not limited to, a controller or electronic control unit (ECU) 112, an output device 114, a user input device 116, and a memory 118. In some embodiments, the control system 110 may be implemented in conjunction with, as a part of, or incorporated into other systems and / or subsystems of the ablation system 100, including, for example, but not limited to, the ablation generator 106, an imaging system, a mapping system, a navigation system, and any other system or subsystem of the ablation system 100.

[0023] The catheter 104 is provided for examining, diagnosing and / or treating tissue in the body, such as cardiac tissue 102. In an exemplary embodiment, the catheter 104 comprises a radiofrequency (RF) ablation catheter. However, it should be understood that the catheter 104 is not limited to an RF ablation catheter. Instead, in other embodiments, the catheter 104 may include an irrigation catheter and / or other types of ablation catheters (e.g., cryoablation, ultrasound, irreversible electroporation, balloon, basket, single electrode, bullet, etc.).

[0024] In an exemplary embodiment, the catheter 104 is electrically coupled to the ablation generator 106 to allow for delivery of RF energy. The catheter 104 may include a cable connector or interface 120, a handle 122, a shaft 124 having a proximal end 126 and a distal end 128 (as used herein, "proximal" refers to a direction toward the end of the catheter 104 proximal to an operator, and "distal" refers to a direction away from the operator and (typically) within a subject or patient), and one or more electrodes 130 mounted in or on the shaft 124 of the catheter 104. In an exemplary embodiment, the electrodes 130 are disposed at or near the distal end 128 of the shaft 124, the electrodes 130 including an ablation electrode disposed at the distal-most end 128 of the shaft 124 for contacting the cardiac tissue 102. The catheter 104 further includes a thermocouple ( Figure 1 ) and a force sensor (also not shown) disposed within and / or near the electrode 130 Figure 1 ). The catheter 104 may further include other components, such as, for example but not limited to, sensors, additional electrodes (eg, ring electrodes) and corresponding conductors or leads, thermocouples, or additional ablation elements, such as a high intensity focused ultrasound ablation element, etc.

[0025] Connector 120 provides mechanical and electrical connections for cables 132 extending from ablation generator 106, control system 110, and other systems and / or subsystems of ablation system 100. Connector 120 is disposed at the proximal end of catheter 104.

[0026] The handle 122 provides an operator with a location to hold the catheter 104 and can further provide a device for steering or guiding the shaft 124 within the patient. For example, the handle 122 can include a device for changing the length of a guidewire extending through the catheter 104 to the distal end 128 of the shaft 124 to steer the shaft 124. The handle 122 can have any suitable configuration that enables the ablation system 100 to function as described herein. In another exemplary embodiment, the catheter 104 can be driven or controlled by a robot. Therefore, instead of the operator manipulating the handle to steer or guide the catheter 104 and its shaft 124, in particular, the catheter 104 is manipulated using a robot.

[0027] The shaft 124 is generally a slender, tubular, flexible member configured for movement in the patient's body. The shaft 124 supports, for example, but not limited to, electrodes 130, thermocouples and force sensors associated therewith, associated conductors, and additional electronic devices that may be used for signal processing or conditioning. The shaft 124 also allows the transportation, delivery, and / or removal of fluids including flushing fluids to the ablation site of the tissue 102. The shaft 124 may additionally or alternatively allow the transportation, delivery, and / or removal of other fluids (cryogenic ablation fluids and / or body fluids), drugs, and / or surgical tools or instruments. The shaft 124 may be made of conventional materials such as polyurethane and define one or more lumens that are configured to accommodate and / or transport at least electrical conductors, fluids, and / or surgical tools. The shaft 124 may be introduced into the heart tissue 102 by conventional introducers. The shaft 124 may then be diverted or guided to the desired position within the heart tissue 102 using a guide wire or other devices known in the art.

[0028] In particular, the ablation generator 106 generates, delivers, and controls RF energy output by the ablation catheter 104 and its electrodes 130. In an exemplary embodiment, the ablation generator 106 includes an RF ablation signal source 134 that is configured to generate an ablation signal that is output across a pair of source connectors: a positive polarity connector SOURCE (+), which can be electrically connected to the tip electrode 130 of the catheter 104; and a negative polarity connector SOURCE (-), which can be electrically connected to one or more return patch electrodes 108 disposed on the patient's skin (e.g., via conductive leads or cables 136).

[0029] It should be understood that the term connector as used herein does not imply a particular type of physical interface mechanism, but is more broadly intended to represent one or more electrical nodes. The source 134 is configured to generate a signal at a predetermined frequency according to one or more user-specified parameters (e.g., power, time, etc.) and under the control of a variety of feedback sensing and control circuits known in the art. The ablation system 100 can also monitor a variety of parameters associated with the ablation procedure, including, for example, impedance, temperature at the distal tip of the catheter, applied ablation energy, and the position of the catheter, and provide feedback about these parameters to an operator or another component within the system 100.

[0030] Now turn to Figure 2-5 , an exemplary ablation catheter 200 suitable for use with the ablation system 100 is shown. The ablation catheter 200 can be substantially similar to the catheter 104, and thus similar features between the catheter 104 and the catheter 200 are labeled using similar reference numerals. Specifically, the ablation catheter 200 includes a shaft 124 ( Figure 4) and electrode 130. In an exemplary embodiment, electrode 130 is embodied as a hollow elongated electrode tip assembly 202 that at least partially defines a distal end 204 of ablation catheter 200.

[0031] In an exemplary embodiment, the electrode tip assembly 202 is a flexible electrode tip assembly, such as the electrode tip assembly described in U.S. Patent No. 9,510,903, which is incorporated herein by reference in its entirety. For example, the electrode tip assembly 202 includes a generally cylindrical sidewall 206 having an irrigation fluid channel 208 extending therethrough. In some embodiments, the fluid channel 208 is formed with an interlocking block pattern, but the fluid channel 208 can have any suitable shape, orientation, and / or pattern that enables the electrode tip assembly 202 to function as described herein. In an exemplary embodiment, the fluid channel 208 is defined in the cylindrical sidewall 206 and extends or perforates through the thickness of the cylindrical sidewall 206 to increase the flexibility of the electrode tip assembly 202. "Flexible" refers to the flexibility of the electrode tip assembly 202 along the longitudinal length of the electrode tip assembly 202 relative to its longitudinal axis 210 ( Figure 4 ) flexure and bending.

[0032] The electrode tip assembly 202 further includes a rod 212 disposed at a proximal end 214 thereof. Specifically, the rod 212 extends proximally of the cylindrical sidewall 206. The rod 212 includes a flange 216 and a cylindrical wall or sleeve 218 extending proximally from the flange 216. The flange 216 extends proximally and radially inwardly from the cylindrical sidewall 206. In addition, the electrode tip assembly 202 includes a cap 220 disposed at a distal end 222 thereof. The cap 220 is coupled to the distal end 224 of the cylindrical sidewall 206.

[0033] In an exemplary embodiment, the shaft 124 of the ablation catheter 200 includes an irrigation conduit 226 extending therethrough. Alternatively, the irrigation conduit 226 may extend along the shaft 124 (e.g., as an external irrigation conduit). The irrigation conduit 226 has a proximal end 228 and a distal end 230 and defines an irrigation lumen 232 therethrough. The irrigation lumen 232 is configured to deliver an irrigation fluid (not shown) to the distal end 204 of the ablation catheter 200, and specifically, to the electrode tip assembly 202. In some embodiments, the irrigation conduit 226 is formed of stainless steel. In other embodiments, the irrigation conduit 226 is formed of any other suitable material.

[0034] The electrode tip assembly 202 is coupled to the irrigation conduit 226 adjacent to the distal end 230 of the irrigation conduit 226. The cylindrical sidewall 206 at least partially defines an inner cavity 234 of the electrode tip assembly 202, wherein the inner cavity 234 is in fluid communication with the irrigation lumen 232. In particular, the distal end of the irrigation lumen 232 (corresponding to the distal end 230 of the irrigation conduit 226) is positioned within the inner cavity 234, so that the irrigation fluid is dispersed from the irrigation lumen 232 into the inner cavity 234. The irrigation fluid is further dispersed to the tissue 102 ( Figure 1 ). The cap 220 further defines an inner cavity 234 and, more specifically, closes the inner cavity 234 at the distal end 224 of the cylindrical sidewall 206.

[0035] In the exemplary embodiment, the shaft 212 defines an outer lumen 236 of the electrode tip assembly 202. More specifically, the cylindrical wall 218 of the shaft 212 defines the outer lumen 236. The outer lumen 236 is adjacent to the inner lumen 234, and at least a portion of the irrigation conduit 226 extends through the outer lumen 236 to the inner lumen 234.

[0036] The electrode tip assembly 202 also includes a fluid manifold 240 disposed within the lumen 234. In some embodiments, the fluid manifold 240 is coupled to the rod 212 of the electrode tip assembly 202. For example, the fluid manifold 240 can be adhered, welded, and / or otherwise mechanically coupled to the flange 216 of the rod 212. In an exemplary embodiment, the fluid manifold 240 includes a tubular sidewall 242 extending distally from the rod 212 and into the lumen 234. The tubular sidewall 242 defines a plurality of fluid distribution holes 244 therein, wherein the fluid distribution holes 244 are circumferentially arranged around the tubular sidewall 242. The fluid manifold 240 is in fluid communication with the distal end 230 of the irrigation conduit 226 and is configured to disperse irrigation fluid therefrom into the lumen 234. Specifically, the fluid distribution holes 244 are arranged and oriented to disperse irrigation fluid radially outward from the fluid manifold 240.

[0037] Additionally, in some embodiments, the fluid manifold 240 defines a first axial fluid passage 246 and a second axial fluid passage 248. The axial fluid passages 246, 248 are configured to axially disperse the flushing fluid from the fluid manifold 240. In an exemplary embodiment, as shown in FIG. Figure 4 As best seen in the drawings, the axial fluid passages 246, 248 are each offset from the longitudinal centerline of the fluid manifold 240, which in the illustrated embodiment corresponds to the longitudinal axis 210. Additionally, in some embodiments, the second axial fluid passage 248 has a longer length than the first axial fluid passage 246. This arrangement of the axial fluid passages 246, 248 (particularly the second axial fluid passage 248) improves the flow of irrigation fluid within the lumen 234 (e.g., by moving the fluid flow from the second axial fluid passage off-center).

[0038] In some embodiments, the fluid manifold 240 is formed as a unitary piece, such as via a molding or machining process. Figure 4 and 5 As best shown in FIG. 1 , the fluid manifold 240 includes an annular flange 250 positioned against and engaged with the rod 212 of the electrode tip assembly 202 (e.g., against the flange 216 of the rod 212). A tubular sidewall 242 extends distally from the annular flange 250. The fluid manifold 240 further includes a distal cap 252 located at a distal end 254 of the tubular sidewall 242 and extending radially inwardly therefrom, and a tubular extension 256 extending distally from the distal cap 252. In such embodiments, the distal cap 252 defines a first axial fluid passage 246 therethrough, and the tubular extension 256 defines a second axial fluid passage 248. The distal cap 252 can be substantially planar and oriented parallel to the annular flange 250. Alternatively, the distal cap 252 can be obliquely angled relative to the tubular sidewall 242. In some embodiments, the distal cap 252 can further define an additional fluid distribution hole 244 therein.

[0039] In other embodiments, Figure 6 As shown in , the fluid manifold 240 is at least partially formed as an extension of the rod 212 of the electrode tip assembly 202. Specifically, the tubular sidewall 242 is integral with the flange 216 of the rod 212 and extends distally from the flange 216 of the rod 212. In such embodiments, the fluid manifold 240 further includes an insert 258 received within the tubular sidewall 242. The insert 258 includes a base 260 and a tubular extension 262 extending distally from the base 260. In such embodiments, the base 260 defines a first axial fluid channel 246, and the tubular extension 262 defines a second axial fluid channel 248. The base 260 is sized and shaped to engage with an inner surface 264 of the tubular sidewall 242. The base 260 can be held against the inner surface 264 of the tubular sidewall 242 via a friction fit and / or via an adhesive, welding, and / or any other suitable coupling method.

[0040] In alternative embodiments, the fluid manifold 240 is formed from two or more components that are subsequently coupled together to form the fluid manifold 240. For example, the fluid manifold 240 may be formed from a base, which may include a flange, a tubular sidewall, and a distal cap, and a separate tubular extension configured to be coupled to the base.

[0041] The ablation catheter 200 further includes a force sensor 270 coupled to the irrigation conduit 226 adjacent the distal end 230. In an exemplary embodiment, the force sensor 270 includes a generally tubular deformable body 272 extending circumferentially around the irrigation conduit 226 adjacent the distal end 230 of the irrigation conduit 226. The electrode tip assembly 202 is further coupled to the force sensor 270. In particular, the electrode tip assembly 202 is coupled to the deformable body 272 of the force sensor 270 and extends distally therefrom to at least partially define the distal end 204 of the ablation catheter 200. In an exemplary embodiment, the outer lumen 236 receives at least a portion of the deformable body 272 therein. For example, the outer lumen 236 receives a distal portion 274 of the deformable body 272 therein.

[0042] The force sensor 270 may include any suitable force sensor, including those described in U.S. Patent Nos. 8,435,232 and 9,597,036, each of which is incorporated herein by reference in its entirety. For example, the force sensor 270 is a fiber optic sensor that senses longitudinal and / or lateral forces applied to the ablation catheter 200 by optically sensing the deformation of the deformable body 272. In particular, a plurality of air gaps 276 are defined in the deformable body 272, which enable optical sensing of the deformation of the deformable body 272.

[0043] In an exemplary embodiment, a seal 278 is positioned within the outer cavity 236 distal to the distal portion 274 of the deformable body 272. The seal 278 is disposed between the electrode tip assembly 202 and the deformable body 272 to inhibit fluid flow (e.g., of an irrigation fluid) between the inner cavity 234 and the outer cavity 236. Specifically, the seal 278 engages with the flange 216 of the rod 212 (e.g., with the proximal-facing surface 280 of the flange 216) and the distal portion 274 of the deformable body 272 to provide a seal between the inner cavity 234 and the outer cavity 236. In some embodiments, the seal 278 comprises a flexible or elastic annular member (e.g., a silicone O-ring). In other embodiments, the seal 278 comprises any other suitable sealing member.

[0044] Electrode tip assembly 202 further includes a spring 282 positioned within lumen 234 against cylindrical sidewall 206. Spring 282 is configured to provide a desired level of stiffness to electrode tip assembly 202 and improve force measurements made by force sensor 270. In some embodiments, as shown in FIG. Figure 2-5 As shown in FIG. 2 , the spring 282 engages the annular flange 250 of the fluid manifold 240 to bias the fluid manifold 240 against the flange 216 of the stem 212 .

[0045] The ablation catheter 200 further includes a temperature sensor 284. The temperature sensor 284 extends distally through at least a portion of the irrigation tubing 226 and into the electrode tip assembly 202. Specifically, the irrigation tubing 226 defines a through hole 286 therein to receive the temperature sensor 284 and associated wiring 288 therethrough. The through hole 286 is oriented at an oblique angle 290 relative to the longitudinal axis 210. The temperature sensor 284 extends through the through hole 286 and into the irrigation tubing 226 (i.e., into the irrigation lumen 232). In some embodiments, the through hole 286 forms an angle 290 of approximately 15° relative to the longitudinal axis 210 so that the temperature sensor 284 can be easily routed through the through hole 286 and longitudinally through the irrigation lumen 232. The angle 290 can be, for example, between approximately 10° and approximately 20° to facilitate assembly of the ablation catheter 200 as described herein. The temperature sensor 284 extends through the distal end 230 of the irrigation tubing 226 and into the fluid manifold 240 , through which the temperature sensor 284 extends into the electrode tip assembly 202 (eg, through the lumen 234 ).

[0046] If the temperature sensor 284 is at a more distal location and / or is not routed into the electrode tip assembly 202 through the irrigation conduit 226 (e.g., through the rod 212), as contemplated in at least some alternative or previous catheters, such an arrangement presents difficulties in adequately sealing the force sensor 270 from the lumen. Specifically, if the air gap 276 is exposed to a fluid (e.g., water, irrigation fluid, bodily fluid, etc.), the optical components of the force sensor 270 may not accurately detect deformations of the deformable body 272, and thus force measurements may be inaccurate. In one proposed solution, an adhesive or epoxy material may be applied to the interface between the force sensor and the tip assembly to inhibit irrigation fluid from entering the force sensor. However, such a seal is manually applied and, if improperly applied, may provide an additional source of interference to the force sensor, thereby resulting in inaccurate force measurements.

[0047] Thus, the ablation catheter 200 provides an improvement over such catheter designs by routing the temperature sensor 284 through the irrigation conduit 226 at a proximal location of the deformable body 272 and into the lumen 234 at a distal location of the deformable body. Thus, the ablation catheter 200 includes a seal 278 that is positioned between the electrode tip assembly 202 and the deformable body 272 during assembly of the ablation catheter 200 to seal the lumen 234 from the deformable body 272. The seal 278 is less susceptible to misuse or improper positioning and is therefore less susceptible to fluid leakage that could interfere with force measurements made by the force sensor 270.

[0048] The temperature sensor 284 is coupled to the electrode tip assembly 202 at its distal end 222. More specifically, the temperature sensor 284 is coupled to the cap 220 of the electrode tip assembly 202. The cap 220 defines a counterbore 292 extending axially therein, and a distal end 294 of the temperature sensor 284 is anchored or potted within the counterbore 292 via an adhesive or epoxy material 296. In some embodiments, the temperature sensor 284 includes a thermocouple sensor 298 at its distal end 294.

[0049] In an exemplary embodiment, the temperature sensor 284 extends from the fluid manifold 240 and into the inner cavity 234 through the first axial fluid passage 246. By routing the temperature sensor 284 through the first axial fluid passage 246 (and therefore not through the second axial fluid passage 248), sufficient fluid flow through the second axial fluid passage 248 can be ensured. That is, the temperature sensor 284 does not interfere with the fluid flow through the second axial fluid passage 248.

[0050] Additionally, the temperature sensor 284 extends through the electrode tip assembly 202 in a non-linear orientation (e.g., in a curved or partially helical configuration). Thus, compared to at least some conventional catheters having a temperature sensor extending linearly through the electrode tip (e.g., parallel to and / or coaxial with its longitudinal axis), the temperature sensor 284 is less likely to share load with the force sensor 270, which may result in inaccurate force measurements.

[0051] In some embodiments, the temperature sensor 284 includes an outer coating (not shown) disposed thereon. The outer coating can be formed of a material that forms a heat shrink coating on the temperature sensor. Suitable materials include, for example, but are not limited to, polymer materials such as polyethylene terephthalate (PET), polyetheretherketone (PEEK), etc. The outer coating can insulate and / or otherwise protect the temperature sensor 284 (including the wiring 288) from the irrigation tubing 226 and / or the irrigation fluid in the lumen 234.

[0052] exist Figure 2-4 In an embodiment of the present invention, the irrigation conduit 226, the deformable body 272, and the electrode tip assembly 202 (including the fluid manifold 240) are generally coaxial and share the longitudinal axis 210. In alternative embodiments, one or more of these components may not be coaxial with any other component. In addition, the temperature sensor 284 is coupled to the cap 220 at the intersection of the longitudinal axis 210 and the cap 220 or at the center of the cap 220 and / or the longitudinal center of the electrode tip assembly 202. Such placement of the temperature sensor 284 can improve the availability of temperature measurements, because off-center temperature measurements may not fully indicate the state of the tissue 102 at the ablation site. In other embodiments, the temperature sensor 284 can be positioned in other ways.

[0053] The ablation catheter 200 may include additional and / or alternative components. Figure 2-4 In the embodiment of the present invention, the ablation catheter 200 includes a device configured to transmit ablation from the ablation generator 106 ( Figure 1 210). The ablation catheter 200 may further include an additional temperature sensor 302 to measure the temperature of and / or adjacent to the force sensor 270. These temperature measurements may be used to account for any effects of heat on the force measurements from the force sensor 270.

[0054] In an exemplary embodiment, the shaft 124 includes a tube 304 that is configured to house various components of the ablation catheter 200. The tube 304 extends from the proximal end 126 of the shaft 124 to the electrode tip assembly 202. For example, the distal end 306 of the tube 304 abuts the flange 216 of the shaft 212. The tube 304 prevents fluid from intruding into the housed components of the ablation catheter 200, such as the force sensor 270, the wiring 300, the temperature sensors 284, 302, etc.

[0055] Figure 7 FIG. 1 is a diagram showing an assembled ablation catheter (such as ablation catheter 200 ( Figure 2-6 )) is a flowchart of one embodiment of a method 700. In some cases, the method 700 is performed manually (eg, by a human operator).

[0056] In an exemplary embodiment, method 700 includes routing 702 a temperature sensor (e.g., temperature sensor 284) through an irrigation lumen (e.g., irrigation lumen 232) defined by an irrigation tubing (e.g., irrigation tubing 226) such that the temperature sensor extends beyond a distal end of the irrigation tubing. In some embodiments, routing 702 includes routing the temperature sensor through a through hole (e.g., through hole 286) formed in the irrigation tubing and oriented at an oblique angle relative to a longitudinal axis of the irrigation tubing.

[0057] The method 700 also includes coupling 704 a deformable body (e.g., deformable body 272) of a force sensor (e.g., force sensor 270) to a distal end of the irrigation tubing and positioning 706 a seal (e.g., seal 278) adjacent a distal portion of the deformable body. In some embodiments, positioning 706 includes positioning a resilient O-ring against the distal end of the deformable body.

[0058] The method 700 further includes routing 708 a temperature sensor into an electrode tip assembly (e.g., electrode tip assembly 202). As described herein, the electrode tip assembly defines an inner cavity and an outer cavity. In some embodiments, the electrode tip assembly further includes a fluid manifold (e.g., fluid manifold 240) disposed within the inner cavity and configured to disperse irrigation fluid from an irrigation conduit. The fluid manifold defines first and second axial fluid channels configured to axially disperse irrigation fluid from the fluid manifold. The first and second axial fluid channels are offset from a longitudinal centerline of the fluid manifold. In such embodiments, routing 708 may include routing the temperature sensor through one of the first and second axial fluid channels.

[0059] Method 700 also includes positioning 710 the distal portion of the deformable body within the outer cavity of the electrode tip assembly. Positioning 710 may further include positioning a seal within the outer cavity, between the distal portion of the deformable body and the proximal portion of the electrode tip assembly (e.g., against flange 216 of stem 212).

[0060] The method 700 further includes coupling 712 the electrode tip assembly to the deformable body such that the electrode tip assembly extends distally from the deformable body and the inner cavity is in fluid communication with the irrigation lumen. As a result of the coupling 712, a seal is disposed between the electrode tip assembly and the deformable body to inhibit fluid flow between the inner cavity and the outer cavity. In some embodiments, the coupling 712 includes compressing the seal between the electrode tip assembly and the deformable body.

[0061] The method 700 further includes coupling 714 the temperature sensor to the electrode tip assembly such that the temperature sensor extends from the electrode tip assembly through the irrigation lumen. Coupling 714 may include potting or otherwise securing the temperature sensor in a distal cap (eg, distal cap 220) of the electrode tip assembly.

[0062] In some embodiments, the electrode tip assembly further includes a rod (e.g., rod 212) disposed at a proximal end of the electrode tip assembly and defining an outer cavity, a cylindrical sidewall (e.g., cylindrical sidewall 206) extending distally from the rod and defining an inner cavity, and a cap coupled to the cylindrical sidewall at its distal end and closing the inner cavity. In such embodiments, coupling 714 may include potting the distal end of the temperature sensor within a counterbore defined in the cap.

[0063] Although certain steps of the example methods are numbered, such numbering does not indicate that the steps must be performed in the order listed. Therefore, specific steps do not need to be performed in the exact order in which they are presented unless their description specifically requires such an order. The steps may be performed in the order listed or in any other suitable order.

[0064] Although the embodiments and examples disclosed herein have been described with reference to specific embodiments, it should be understood that these embodiments and examples are merely illustrations of the principles and applications of the present disclosure. It should therefore be understood that various modifications may be made to the illustrative embodiments and examples and other arrangements may be designed without departing from the spirit and scope of the present disclosure as defined by the claims. Therefore, the present application is intended to encompass modifications and variations of these embodiments and their equivalents.

[0065] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the disclosure, including making and using any device or system and performing any incorporated method. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. These other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that do not differ substantially from the literal language of the claims.

Claims

1. An ablation catheter, comprising: an irrigation conduit having a proximal end and a distal end, the irrigation conduit defining an irrigation lumen configured to deliver an irrigation fluid to the distal end of the ablation catheter; a force sensor including a deformable body coupled to the irrigation conduit near a distal end thereof; an electrode tip assembly coupled to and extending distally from the deformable body, wherein the electrode tip assembly defines an inner lumen in fluid communication with the irrigation lumen and an outer lumen receiving a distal portion of the deformable body; a seal disposed between the electrode tip assembly and the deformable body, wherein the seal inhibits fluid flow between the inner cavity and the outer cavity; and A temperature sensor is coupled to the electrode tip assembly and extends from the electrode tip assembly through the irrigation lumen.

2. The ablation catheter according to claim 1, wherein: The electrode tip assembly comprises: a rod disposed at a proximal end of the electrode tip assembly and defining the outer lumen; and A cylindrical sidewall extends distally from the shaft and defines the lumen.

3. The ablation catheter according to claim 2, wherein: The rod includes a flange and a cylindrical wall extending proximally from the flange, wherein the cylindrical wall defines the outer cavity for receiving the distal portion of the deformable body, and wherein the seal is disposed between and engaged with the flange and the distal portion of the deformable body.

4. The ablation catheter according to claim 2, wherein: The electrode tip assembly further includes a cap coupled to the cylindrical sidewall at a distal end thereof and closing the inner cavity, wherein the cap defines a counterbore extending axially through the cap, and wherein the distal end of the temperature sensor is potted within the counterbore.

5. The ablation catheter according to claim 2, wherein: The electrode tip assembly further includes a fluid manifold disposed within the inner cavity and configured to disperse irrigation fluid from the irrigation conduit, wherein the fluid manifold includes a tubular sidewall extending distally from the shaft, the tubular sidewall defining a plurality of fluid distribution holes therein, wherein the fluid distribution holes are oriented to disperse irrigation fluid radially outward from the fluid manifold.

6. The ablation catheter according to claim 5, wherein: The fluid manifold defines first and second axial fluid passages configured to axially disperse flushing fluid from the fluid manifold, wherein the first and second axial fluid passages are offset from a longitudinal centerline of the fluid manifold, and wherein the second axial fluid passage has a greater length than the first axial fluid passage.

7. The ablation catheter according to claim 6, wherein: The temperature sensor extends through the first axial fluid passage.

8. The ablation catheter according to claim 6, wherein: The fluid manifold further includes an insert received within the tubular sidewall, wherein the insert includes a base and a tubular extension extending distally from the base, wherein the base defines the first axial fluid passage, and wherein the tubular extension defines the second axial fluid passage.

9. The ablation catheter according to claim 6, wherein: The fluid manifold is formed as a unitary piece, and wherein the fluid manifold further comprises: an annular flange configured to engage the stem, wherein the tubular sidewall extends distally from the annular flange; a distal cap located at a distal end of the tubular sidewall, wherein the distal cap defines the first axial fluid passage; and A tubular extension extends distally from the distal cap, wherein the tubular extension defines the second axial fluid passage.

10. The ablation catheter according to claim 9, wherein: The electrode tip assembly further includes a spring configured to engage the annular flange to bias the fluid manifold against the stem.

11. The ablation catheter according to claim 2, wherein: The cylindrical sidewall includes at least one irrigation fluid channel defined therein and extending therethrough, wherein the at least one irrigation fluid channel provides flexibility in the sidewall for bending movement of the electrode tip assembly relative to a longitudinal axis of the sidewall when the electrode tip assembly is placed under a load.

12. The ablation catheter according to claim 1, wherein: The electrode tip assembly is a flexible electrode tip assembly.

13. The ablation catheter according to claim 1, wherein: The flushing conduit defines a through-hole oriented at an oblique angle relative to a longitudinal axis of the flushing conduit, and wherein the temperature sensor extends through the through-hole.

14. The ablation catheter according to claim 1, wherein: The seal comprises a resilient O-ring.

15. The ablation catheter according to claim 1, wherein: Temperature sensors include thermocouples.

16. A method of assembling an ablation catheter, the method comprising: routing a temperature sensor through an irrigation lumen defined by an irrigation tubing such that the temperature sensor extends beyond a distal end of the irrigation tubing; coupling a deformable body of a force sensor to the distal end of the irrigation conduit; positioning a seal adjacent a distal portion of the deformable body; routing the temperature sensor into an electrode tip assembly, wherein the electrode tip assembly defines an inner cavity and an outer cavity; positioning the distal portion of the deformable body within the outer lumen of the electrode tip assembly; coupling the electrode tip assembly to the deformable body such that the electrode tip assembly extends distally from the deformable body and the inner lumen is in fluid communication with the irrigation lumen, wherein the seal is disposed between the electrode tip assembly and the deformable body to inhibit fluid flow between the inner lumen and the outer lumen; and The temperature sensor is coupled to the electrode tip assembly such that the temperature sensor extends from the electrode tip assembly through the irrigation lumen.

17. The method according to claim 16, wherein: The electrode tip assembly comprises: a rod disposed at a proximal end of the electrode tip assembly and defining the outer lumen; a cylindrical sidewall extending distally from the shaft and defining the lumen; and a cap coupled at its distal end to the cylindrical sidewall and closing the inner cavity, Wherein, coupling the temperature sensor to the electrode tip assembly includes potting a distal end of the temperature sensor within a counterbore defined in the cap.

18. The method according to claim 16, wherein: The electrode tip assembly further includes a fluid manifold disposed within the inner cavity and configured to disperse irrigation fluid from the irrigation conduit, wherein the fluid manifold defines first and second axial fluid passages, the first and second axial fluid passages configured to axially disperse irrigation fluid from the fluid manifold, wherein the first and second axial fluid passages are offset from a longitudinal centerline of the fluid manifold, wherein routing the temperature sensor into the electrode tip assembly includes routing the temperature sensor through one of the first and second axial fluid passages.

19. The method according to claim 16, wherein: Routing the temperature sensor through the irrigation lumen includes routing the temperature sensor through a through-hole formed in the irrigation tubing and oriented at an oblique angle relative to a longitudinal axis of the irrigation tubing.

20. A catheter system comprising: An ablation catheter comprising: an irrigation conduit having a proximal end and a distal end, the irrigation conduit defining an irrigation lumen configured to deliver an irrigation fluid to the distal end of the ablation catheter; a force sensor including a deformable body coupled to the irrigation conduit near a distal end thereof; an electrode tip assembly coupled to and extending distally from the deformable body, wherein the electrode tip assembly defines an inner lumen in fluid communication with the irrigation lumen and an outer lumen receiving a distal portion of the deformable body; a seal disposed between the electrode tip assembly and the deformable body, wherein the seal inhibits fluid flow between the inner cavity and the outer cavity; and a temperature sensor coupled to the electrode tip assembly and extending from the electrode tip assembly through the irrigation lumen; and An ablation generator is electrically coupled to the electrode tip assembly and configured to provide ablation energy thereto.

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