WO2021105903A1 - Ablation catheter tip with flexible electronic circuitry - Google Patents

Abstract

Aspects of the present disclosure are directed to, for example, a high-thermal-sensitivity ablation catheter tip. More specifically, various aspects of the present disclosure are directed to improved thermocouple response to temperature changes associated with an ablation electrode and/or tissue in contact therewith. Such an ablation catheter tip facilitates reduced lag in an ablation control system's response to the sensed temperature changes.

Description

ABLATION CATHETER TIP WITH FLEXIBLE ELECTRONIC CIRCUITRY

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of United States provisional application no 62/940,732, filed 26 November 2019, which is hereby incorporated by reference as though fully set forth herein.

[0002] This application incorporates by reference as though fully set forth herein: United States application no. 15/088,036, filed 31 March 2016, now pending, which claims the benefit of United States provisional application no. 62/141,066, filed 31 March 2015; United States application no. 15/088,052, filed 31 March 2016, now pending, which claims the benefit of United States provisional application no. 62/198,114, filed 28 July 2015; United States application no. 15/723,701, filed 3 October 2017, now pending, which claims the benefit of United States provisional application no. 62/404,038, filed 4 October 2016; United States application no. 15/724,157, filed 3 October 2017, now pending, which claims the benefit of United States provisional application no. 62/404,060, filed 4 October 2016; international application no. PCT/US2017/049264, filed 30 August 2017, now pending, which claims the benefit of United States provisional application no. 62/404,013, filed 4 October 2016; United States provisional application no. 62/642,178, filed 13 March 2018; United States provisional application no. 62/824,840, filed 27 March 2019; United States provisional application no. 62/824,844, filed 27 March 2019; United States provisional application no. 62/824,846, filed 27 March 2019; United States provisional application no. 62/832,246, filed 10 April 2019; United States provisional application no. 62/832,248, filed 10 April 2019; and United States provisional application filed concurrently herewith under docket no. 13674USL1/065513-002154.

BACKGROUND OF THE DISCLOSURE a. Field

[0003] The instant disclosure relates to various types of medical catheters, in particular catheters for diagnostics within, and/or treatment of, a patient’s cardiovascular system. In one embodiment, the instant disclosure relates to an ablation catheter for treating cardiac arrhythmias within a cardiac muscle. Various aspects of the instant disclosure relate to force sensing systems capable of determining a force applied at a distal tip of the ablation catheter. [0004] The present disclosure further relates to low thermal mass ablation catheter tips (also known as high-thermal-sensitivity catheter tips) and to systems for controlling the delivery of radio-frequency energy to such catheter tips during ablation procedures. b. Background

[0005] Exploration and treatment of various organs or vessels has been made possible using catheter-based diagnostic and treatment systems. These catheters may be introduced through a vessel leading to the cavity of the organ to be explored, and/or treated. Alternatively, the catheter may be introduced directly through an incision made in the wall of the organ. In this manner, the patient avoids the trauma and extended recuperation times typically associated with open surgical procedures.

[0006] The human heart routinely experiences electrical currents traversing its many layers of tissue. Just prior to each heart contraction, the heart depolarizes and repolarizes as electrical currents spread across the heart. In healthy hearts, the heart will experience an orderly progression of depolarization waves. In unhealthy hearts, such as those experiencing atrial arrhythmia, including for example, ectopic atrial tachycardia, atrial fibrillation, and atrial flutter, the progression of the depolarization wave becomes chaotic.

[0007] Catheters are used in a variety of diagnostic and/or therapeutic medical procedures to diagnose and correct conditions such as atrial arrhythmia. Typically, in such a procedure, a catheter is manipulated through a patient’s vasculature to the patient’s heart carrying one or more end effectors which may be used for mapping, ablation, diagnosis, or other treatment. Where an ablation therapy is desired to alleviate symptoms including atrial arrhythmia, an ablation catheter imparts ablative energy to cardiac tissue to create a lesion in the cardiac tissue. The lesioned tissue is less capable of conducting electrical signals, thereby disrupting undesirable electrical pathways and limiting or preventing stray electrical signals that lead to arrhythmias. The ablation catheter may utilize ablative energy including, for example, radio frequency (RF), cryoablation, laser, chemical, and high-intensity focused ultrasound. Ablation therapies often require precise positioning of the ablation catheter, as well as precise pressure exertion for optimal ablative-energy transfer into the targeted myocardial tissue. Excess pressure between the ablation catheter tip and the targeted myocardial tissue may result in excessive ablation which may permanently damage the cardiac muscle and/or surrounding nerves. When the contact pressure between the ablation catheter tip and the targeted myocardial tissue is below a target pressure, the efficacy of the ablation therapy may be reduced.

[0008] Ablation therapies are often delivered by making a number of individual ablations in a controlled fashion in order to form a lesion line. To improve conformity of the individual ablations along the lesion line, it is desirable to precisely control the position at which the individual ablations are conducted, the ablation period, and the contact pressure between the ablation catheter tip and the targeted tissue. All of these factors affect the conformity of the resulting lesion line. Catheter localization systems, in conjunction with mapping systems, have vastly improved a clinician’s ability to precisely position the ablation catheter tip for an ablation. [0009] The foregoing discussion is intended only to illustrate the present field and should not be taken as a disavowal of claim scope.

BRIEF SUMMARY OF THE DISCFOSURE

[0010] It is desirable to control the delivery of RF energy to a catheter to enable the creation of lesions in tissue, by keeping the generator power setting sufficiently high to form adequate lesions, and mitigating against overheating of tissue. Accordingly, aspects of the present disclosure are directed toward an ablation catheter tip including high thermal sensitivity materials which facilitate near real-time temperature sensing at the ablation catheter tip. Further aspects of the present disclosure are directed to improved ablation catheter force measurements in response to tissue contact on the ablation catheter tip.

[0011] Various embodiments of the present disclosure are directed to a high-thermal- sensitivity ablation catheter tip. The tip including an ablation electrode to deliver an ablation therapy to tissue in contact with or in close proximity thereto, and a flexible electronic circuit proximal the ablation electrode. The flexible electronic circuit includes a plurality of electrodes configured and arranged to sense electrophysiology characteristics of the tissue in contact with or in close proximity to the ablation electrode. In more specific embodiments, the ablation electrode and the flexible electronic circuit are in contact with one another.

[0012] Some embodiments of the present disclosure are further direct to a high-thermal- sensitivity ablation catheter tip. The tip including an ablation electrode, a flexible electronic circuit, and thermally conductive ring. The ablation electrode delivers an ablation therapy to tissue in contact with or in close proximity thereto. The flexible electronic circuit is proximal the ablation electrode and includes a plurality of thermocouples which are circumferentially distributed around the ablation catheter tip. The thermally conductive ring circumferentially encompasses the flexible electronic circuit, and the ring draws heat away from a proximal end of the ablation electrode. In more specific embodiments, the plurality of thermocouples sense a temperature of the tissue and transmit an electrical signal indicative of the sensed temperature to controller circuitry of an ablation catheter. The ring is electrically insulative and electrically insulates the plurality of thermocouples from a current emitted from the ablation electrode, while heat from the ablation electrode and tissue in contact therewith, or in close proximity to, is readily transferred to the thermocouples via the ring.

[0013] The foregoing and other aspects, features, details, utilities, and advantages of the present disclosure will be apparent from reading the following description and claims, and from reviewing the accompanying drawings.

DESCRIPTION OF THE DRAWINGS

[0014] Various example embodiments may be more completely understood in consideration of the following detailed description in connection with the accompanying drawings.

[0015] Figure 1 is a diagrammatic overview of an ablation catheter system including a force sensing subsystem, consistent with various embodiments of the present disclosure;

[0016] Figure 2A is a side view of an ablation catheter tip assembly, consistent with various embodiments of the present disclosure;

[0017] Figure 2B is a perspective side view of the ablation catheter tip assembly of Figure 2A, consistent with various embodiments of the present disclosure;

[0018] Figure 2C is a partial cross-sectional, perspective side view of the ablation catheter tip assembly of Figure 2A, consistent with various embodiments of the present disclosure;

[0019] Figure 2D is a perspective side view of a partial ablation catheter tip assembly, consistent with various embodiments of the present disclosure;

[0020] Figure 2E is a cross-sectional side view of the ablation catheter tip assembly of Figure 2A, consistent with various embodiments of the present disclosure;

[0021] Figure 3 is a top view of a pair of flexible electronic circuits (also referred to as a flexible circuit), consistent with various aspects of the present disclosure. [0022] Figure 4 A is a side view of an ablation catheter tip assembly, consistent with various embodiments of the present disclosure;

[0023] Figure 4B is a perspective side view of the ablation catheter tip assembly of Figure 4A, consistent with various embodiments of the present disclosure;

[0024] While various embodiments discussed herein are amenable to modifications and alternative forms, aspects thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure including aspects defined in the claims. In addition, the term “example” as used throughout this application is only by way of illustration, and not limitation.

DETAILED DESCRIPTION OF EMBODIMENTS

[0025] Various aspects of the present disclosure are directed to medical catheters, in particular, catheters for diagnostics within, and/or treatment of, a patient’s cardiovascular system. In many embodiments, the instant disclosure relates to an ablation catheter for treating cardiac arrhythmias within a cardiac muscle, such as atrial fibrillation. To diagnose and treat symptoms related to atrial fibrillation, for example, a distal tip of the catheter may include sensing electrodes (also referred to as spot electrodes and electrophysiology), and may also be used to confirm a successful ablation therapy by verifying isolation of stray electrical signals ( e.g ., those caused by arrhythmic foci) from a left atrium of the cardiac muscle.

[0026] During a non-invasive intravascular ablation therapy, it is desirable to precisely control delivery of energy (e.g., radio-frequency, thermal, etc.) at a distal tip of the catheter to enable lesion formation in the myocardial tissue. During ablation therapy, generator power must remain sufficiently high to form adequate lesions, while mitigating against overheating of tissue (associated with steam pops, charring and/or coagulation on the ablation catheter tip). Accordingly, aspects of the present disclosure are directed toward an ablation catheter tip with high thermal sensitivity materials which facilitate near real-time temperature sensing at the ablation catheter tip.

[0027] Further aspects of the present disclosure are directed to improved ablation catheter force measurements in response to tissue contact on the ablation catheter tip. It has been discovered that consistent force, during a series of tissue ablations, forms a more uniform and transmural lesion line. Such uniform lesion lines have been found to better isolate the electrical impulses produced by arrhythmic foci, thereby improving the overall efficacy of the ablation therapy. To achieve such consistent force, aspects of the present disclosure utilize a deformable body in the ablation catheter tip. The deformable body deforms in response to forces being exerted upon the ablation catheter tip. The deformation of the deformable body may then be measured by a measurement device ( e.g ., ultrasonic, magnetic, optical, interferometry, etc.). Based on the tuning of the deformable body and/or the calibration of the measurement device, the deformation can then be associated with a force exerted on the ablation catheter tip (e.g., via a lookup table, formula(s), calibration matrix, etc.).

[0028] Various embodiments of the present disclosure are directed to an ablation catheter with thermocouples and microelectrodes positioned immediately proximal to an ablation tip. [0029] To improve safety and effectiveness of intracardiac ablation therapies, aspects of the present disclosure monitor tip-tissue temperatures and local electrograms. The need to monitor tip-tissue temperature has become more critical as many physicians have moved to therapy protocols utilizing higher power and shorter duration ablations. The ablation electrode is commonly manufactured with sharp corners at a proximal end, and therefore during ablation therapy may be subject to “hot zones” due to the increased current density. These “hot zones,” when contacted by myocardial tissue may subject the tissue to undesirably high temperatures which can, in extreme cases, result in steam pops. Aspects of the present disclosure monitor the temperature at or near the proximal end of the ablation electrode during ablation therapy, and in response to temperature signals received by controller circuitry, the controller circuitry may adjust power delivery to the ablation electrode - thereby improving therapy efficacy, and safety by reducing the possibility of char, coagulum, or a steam pop.

[0030] Aspects of the present disclosure are further directed to increasing ablation catheter capability. For example, it has been discovered that ablation catheters may benefit from the ability to measure localized temperature, electrograms, voltage, and impedance with the ablation catheter - improving patient safety and facilitating improved patient outcomes. Such capabilities, including electrodes and thermocouples may be implemented on, or in close proximity to, an ablation electrode. Various embodiments of the present disclosure facilitate capturing local electrophysiology measurements with the ablation catheter, while further minimizing complexity and cost of the catheter.

[0031] To minimize complexity and cost of the various ablation catheters disclosed herein, a flexible ablation catheter tip utilizes one or more flex circuits including thermocouples and microelectrodes which are communicatively coupled to controller circuitry. These flex circuit(s) may be routed through an internal lumen of the catheter shaft and extend proximally along a length of the catheter shaft toward controller circuitry which is communicatively coupled to a catheter handle of the ablation catheter via a connector.

[0032] Several embodiments of the present disclosure are directed to the integration of localized temperature and/or voltage/impedance information into an ablation catheter, with the safety profile of the FlexAbility™ ablation catheter (manufactured by Abbott Laboratories). In such an embodiment, a flexible electronic circuit (with thermocouples and/or microelectrodes communicatively coupled thereto) may be wrapped around a catheter shaft immediately proximal to an ablation electrode/tip. The proximity of the thermocouples facilitates, for example, temperature monitoring of an ablation electrode hot zone (that may occur) during ablation therapy at a proximal edge of the ablation electrode/tip. The use of the flexible electronic circuit assembly reduces assembly complexity by placing the flexible electronic circuit (or flex circuit) outside of an internal diameter of the tip, where space is more limited. Furthermore, external temperature sensor positioning may improve temperature sensing accuracy (as the thermocouples are not in contact with or otherwise washed out by catheter irrigation flow within the catheter shaft) and benefit from near real-time temperature sensing due to the thermal conductivity between the ablation electrode and flex circuit. The flex circuit may then communicate electrical signals indicative of the sensed temperatures at the one or more thermocouples to controller circuitry.

[0033] In one embodiment of the present disclosure, an outer surface of a flex circuit is flush (or nearly flush) with an outer surface of a catheter shaft and ablation electrode/tip to facilitate a smooth, atraumatic transition between the tip, flex circuit, and shaft. The flex circuit may be routed circumferentially around a diameter of the shaft (e.g., between the irrigation manifold and the ablation electrode/tip) and extend into an interior of the catheter shaft via an irrigation manifold (as discussed in more detail in reference to the figures). In some embodiments, there may also be a structure between the flex circuit and the irrigation manifold to thermally insulate the thermocouples from the irrigant in the manifold. The flex circuit may be fixed to the irrigation manifold either with an adhesive layer fixed to the flex circuit, with adhesive applied to the irrigation manifold, or by other means such as a reflow process.

[0034] Referring now to the drawings wherein like reference numerals are used to identify identical components in the various views, Figure 1 generally illustrates an ablation catheter system 10 having an elongated medical device 19 that includes a sensor assembly 11 (e.g., fiber optic based distance measurement sensor) at a distal end 24, and configured to be used in the body for medical procedures. The elongated medical device 19 may be used for diagnosis, visualization, and/or treatment of tissue 13 (such as cardiac or other tissue) in the body. For example, the medical device 19 may be used for ablation therapy of tissue 13 or mapping of a patient’s body 14. Figure 1 further illustrates various sub-systems included in the ablation catheter system 10. The system 10 may include a main computer system 15 (including an electronic control unit 16 and data storage 17, e.g., memory). The computer system 15 may further include conventional interface components, such as various user input/output mechanisms 18A and a display 18B, among other components. Information provided by the sensor assembly 11 may be processed by the computer system 15 and may provide data to the clinician via the input/output mechanisms 18A and/or the display 18B, or in other ways as described herein. Specifically, the display 18B may visually communicate a force exerted on the elongated medical device 19 - where the force exerted on the elongated medical device 19 is detected in the form of a deformation of at least a portion of the elongated medical device by the sensor assembly 11, and the measured deformation is processed by the computer system 15 to determine the force exerted.

[0035] In the illustrative embodiment of FIG. 1, the elongated medical device 19 may include a cable connector or interface 20, a handle 21, a tubular body or shaft 22 having a proximal end 23 and a distal end 24. The elongated medical device 19 may also include other conventional components not illustrated herein, such as a temperature sensor, additional electrodes, and corresponding conductors or leads. The connector 20 may provide mechanical, fluid and/or electrical connections for cables 25, 26 extending from a fluid reservoir 12 and a pump 27 and the computer system 15, respectively. The connector 20 may comprise conventional components known in the art and, as shown, may be disposed at the proximal end of the elongated medical device 19.

[0036] The handle 21 provides a portion for a user to grasp or hold the elongated medical device 19 and may further provide a mechanism for steering or guiding the shaft 22 within the patient’s body 14. For example, the handle 21 may include a mechanism configured to change the tension on a pull-wire extending through the elongated medical device 19 to the distal end 24 of the shaft 22 or some other mechanism to steer the shaft 22. The handle 21 may be conventional in the art, and it will be understood that the configuration of the handle 21 may vary. In an embodiment, the handle 21 may be configured to provide visual, auditory, tactile and/or other feedback to a user based on information received from the sensor assembly 11. For example, if contact to tissue 13 is made by distal end 24, the sensor assembly 11 may transmit data to the computer system 15 indicative of contact. In response to the computer system 15 determining that the data received from the sensor assembly 11 is indicative of contact between the distal end 24 and a patient’s body 14, the computer system 15 may operate a light-emitting - diode on the handle 21, a tone generator, a vibrating mechanical transducer, and/or other indicator(s), the outputs of which could vary in proportion to the calculated contact force.

[0037] The computer system 15 may utilize software, hardware, firmware, and/or logic to perform a number of functions described herein. The computer system 15 may be a combination of hardware and instructions to share information. The hardware, for example may include processing resource 16 and/or a memory 17 (e.g., non-transitory computer-readable medium (CRM) database, etc.). A processing resource 16, as used herein, may include a number of processors capable of executing instructions stored by the memory resource 17. Processing resource 16 may be integrated in a single device or distributed across multiple devices. The instructions (e.g., computer-readable instructions (CRI)) may include instructions stored on the memory 17 and executable by the processing resource 16 for force detection.

[0038] The memory resource 17 is communicatively coupled with the processing resource 16. A memory 17, as used herein, may include a number of memory components capable of storing instructions that are executed by processing resource 16. Such a memory 17 may be a non-transitory computer readable storage medium, for example. The memory 17 may be integrated in a single device or distributed across multiple devices. Further, the memory 17 may be fully or partially integrated in the same device as the processing resource 16 or it may be separate but accessible to that device and the processing resource 16. Thus, it is noted that the computer system 15 may be implemented on a user device and/or a collection of user devices, on a mobile device and/or a collection of mobile devices, and/or on a combination of the user devices and the mobile devices.

[0039] The memory 17 may be communicatively coupled with the processing resource 16 via a communication link (e.g., path). The communication link may be local or remote to a computing device associated with the processing resource 16. Examples of a local communication link may include an electronic bus internal to a computing device where the memory 17 is one of a volatile, non-volatile, fixed, and/or removable storage medium in communication with the processing resource 16 via the electronic bus.

[0040] In various embodiments of the present disclosure, the computer system 15 may receive optical signals from a sensor assembly 11 via one or more optical fibers extending a length of the catheter shaft 22. A processing resource 16 of the computer system 15 may execute an algorithm stored in memory 17 to compute a force exerted on distal end 24, based on the received optical signals.

[0041] United States Patent no. 8,567,265 discloses various optical force sensors for use in medical catheter applications, such optical force sensors are hereby incorporated by reference as though fully disclosed herein.

[0042] Figure 1 further depicts an RF generator 40 operatively connected to the computer system 15, which is operatively connected to the elongated medical device 19. In this figure, a number of possible wired and/or wireless communication pathways are shown. For example, the computer system 15 may receive temperature feedback readings from at least one temperature sensor mounted on or near the distal end 24 of the catheter shaft 22. In various embodiments disclosed herein, the catheter may include multiple thermal sensors (for example, thermocouples or thermistors), as described further below. The temperature feedback readings may be the highest reading from among all of the individual temperature sensor readings, or it may be, for example, an average of all of the individual readings from all of the temperature sensors. The computer system 15 may then communicate to the RF generator 40 the highest temperature measured by any of the plurality of temperature sensors mounted within the sensor assembly 11. This could be used to trigger a temperature-based shutdown feature in the RF generator for patient safety. In other words, the temperature reading or readings from the catheter may be sent to the computer system 15, which may then feed the highest temperature reading to the RF generator 40 so that the generator can engage its safety features and shut down if the temperature reading exceeds a (safety) threshold.

[0043] In an alternative operation of the system 10 of FIG. 1, the computer system 15, in response to elevated temperature feedback from the thermal sensors, may operate the RF generator 40 in a pulsed manner. By pulsing the RF signal, the power can remain at a desired power level (e.g., 50 or 60 Watts) rather than being reduced to an ineffective level when excessive temperature is sensed by the catheter tip. In particular, rather than reducing the power to control temperature, the power may be delivered in a pulsed manner; by pulsing the RF signals, and controlling the length of pulses and gaps between pulses, tip temperature may be controlled as a surrogate for controlling actual tissue temperature. Similarly, instead of pulsing the power, the power may also be titrated in such a manner.

[0044] In the embodiment depicted in FIG. 1 , the RF generator 40 may include pulse control hardware, software, and/or firmware built into the generator itself.

[0045] Figure 2 A is a side view of an ablation catheter tip assembly 200, and Figure 2B is a perspective side view of the ablation catheter tip assembly 200 of Figure 2A. The ablation catheter tip assembly 200 includes a conductive tip 201 and conductive shell 202 coupled to a distal end of a catheter shaft 204. In the present embodiment, the conductive shell and tip are capable of receiving radio-frequency energy from a radio-frequency generator (e.g., RF Generator 40 as shown in FIG. 1), and transmitting that energy into myocardial tissue in contact with the conductive shell and/or tip (or in close proximity thereto). In some embodiments, as shown in FIG. 2A, the ablation catheter may be irrigated and include a plurality of irrigant apertures 208 _I-N which extend through the conductive shell 202, and deliver irrigant into contact with the target therapy tissue. Furthermore, the plurality of irrigant apertures 208_I-N may also facilitate desirable flexible characteristics of the ablation catheter tip assembly 200 - such that in response to contact with target tissue the assembly deforms to increase tip-tissue contact area. [0046] At a distal end 205 of the tip assembly 200, and in some embodiments at a juncture between the conductive shell 202 and the conductive tip 201, one or more flexible circuits 291_B may extend from an interior cavity of the catheter and extend distally along a surface of the conductive tip. The one or more flexible circuits 291_B include electrodes 206i-₄ which facilitate electrophysiology mapping, impedance detection, and/or temperature sensing (where the one or more flex circuits include thermocouples) of tissue in contact with a distal tip 201 of the tip assembly 200. The one or more flexible circuits 291_B may be coupled to the distal tip 201 using known methods ( e.g ., adhesive, a re-flow process, etc.). In the present embodiment, the one or more flexible circuits 291_B extend distally within trenches (which extend into an outer surface of the distal tip) that facilitate positioning of the electrodes 2O6_1-4 substantially flush with the outer surface of the distal tip. As a result, the electrodes 2O6_1-4 facilitate a smooth, atraumatic transition between the tip, flex circuit, and shaft.

[0047] At a proximal end 210 of the tip assembly 200 of FIGs. 2A and 2B, and in some embodiments at a juncture between conductive shell 202 and catheter shaft 204, a flexible circuit 291_A may extend from an interior cavity of the catheter and extend circumferentially around the catheter. The flexible circuit 291_A includes electrodes 207_I-4 which facilitate electrophysiology mapping, impedance detection, etc. In some further embodiments, a sub-layer of the flexible circuit may include thermocouples (which may be directly underneath the electrodes 207_I-4) to facilitate temperature sensing of tissue in contact with the flexible circuit 291_A. The flexible circuit 291A may be coupled about the exterior of the catheter shaft using known methods (e.g., adhesive, a re-flow process, etc.). In the present embodiment, the flexible circuit 291_A extends circumferentially about the catheter shaft within a trench (which extends between the catheter shaft 204 and the conductive shell 202) and which facilitates positioning of the electrodes 207_I-4 substantially flush with an outer surface of the distal tip assembly 200. As a result, the inset placement of the electrodes 207I-4 within the trench facilitates a smooth, atraumatic transition between the conductive shell, electrode face, and shaft.

[0048] The placement of flexible circuit 291_A immediately proximal 210 to the conductive shell 202 facilitates temperature monitoring of a hot zone that may occur during ablation at a proximal edge of the conductive shell 202, while reducing complexity of the tip assembly 200 by placing a sensor portion of the flex circuit 291_A on the exterior of the tip assembly (where space is more readily available than inside the tip assembly). Moreover, in many embodiments, placement of the flex circuit 291_A into direct contact with tissue improves temperature sensing of the thermocouples, and the thermocouples are not as susceptible to signal error associated with a flow of irrigant through the catheter shaft. The various electrical signals indicative of temperature and/or electrophysiology signals of the contacted tissue may be transmitted to a connector in a catheter handle via one or both of the flex circuits 291_A, B extending a length of the catheter shaft 204, or in conjunction with one or more additional flex circuit(s) joined to the flex circuits 291_{A, B} or via wires communicatively coupled to the flex circuits 291_A, B and extending proximally the remaining length of the catheter shaft to the catheter handle.

[0049] Distally extending portions of the one or more flexible circuits 291_A, B may be routed along a lumen of the catheter shaft and may pass through an irrigation manifold before exiting the catheter shaft 204. As shown in the embodiment of FIGs. 2A and 2B, the flex circuit 291_A is circumferentially wrapped about the catheter shaft between the catheter shaft 204 and the conductive shell 202. In some embodiments, as discussed in more detail in referenced to FIG. 2C, the flex circuit 291_A may be structurally supported about an inner diameter, and the structural support may also have the benefit of thermally insulating one or more thermocouples on the flex circuit from irrigant flowing through an irrigant manifold. The flex circuit 291_A may also be fixed to the irrigation manifold, for example, either with an adhesive layer fixed to the flex circuit, with adhesive applied to the irrigation manifold, or by other means such as a reflow process.

[0050] When the electrodes are placed into contact with tissue (e.g., myocardial tissue), the electrodes receive electrical signal information indicative of the health of the tissue, the strength and directionality of electrical signals being transmitted through the tissue, among other information that is useful to a clinician to diagnose, treat, and determine therapy efficacy.

[0051] In various embodiments of the present disclosure, it may be necessary to isolate the electrodes 206i-₄ and 2071 from a conductive shell 202 of the ablation electrode to reduce RF- related interference received by the electrodes 206i₄ and 207i₄. Accordingly, various embodiments of the present disclosure are directed to distal tip assemblies where the flexible circuits 291_A, B may be electrically insulated from the ablation electrode RF-related interference, but thermally conductive so as to facilitate near real-time temperature sensing of the ablation electrode via one or more thermocouples on the flexible circuits. In some specific embodiments, an electrically insulative material may at least partially circumscribe one or more of the electrodes 206i-₄ and 2071 to prevent/limit RF-related signal interference from being received by the electrodes.

[0052] The conductive shell 202 and conductive tip 201, disclosed herein, may comprise for example platinum, a platinum iridium composition, or gold. The conductive shell may comprise one or more parts or components (including the conductive tip 201). As shown in Figs. 2A and 2B, the conductive shell may comprise a hemispherical or nearly-hemispherical domed distal end 205 and a cylindrical body 202. In one embodiment, the wall thickness of the conductive shell is 0.002 inches, but alternative wall thicknesses may also be utilized. The conductive shell may be formed or manufactured by, for example, forging, machining, drawing, spinning, or coining. Also, the conductive shell could be constructed from molded ceramic that has, for example, sputtered platinum on its external surface. In another alternative embodiment, the conductive shell could be constructed from conductive ceramic material.

[0053] Figure 2C is a partial cross-sectional, perspective side view of the ablation catheter tip assembly 200 of Figure 2 A. As shown in FIG. 2C, flexible circuit 291_A extends distally from a catheter handle through catheter shaft 204, before transitioning into an irrigant lumen 216 at irrigant manifold 215. At a distal end of the irrigant manifold 215, the flexible circuit 291_A extends radially outward and circumferentially wraps about an outer diameter of the ablation catheter tip assembly 200 between the conductive shell 202 and the catheter shaft 204.

[0054] As shown in FIG. 2C, the flexible circuit 291_A is inset relative to the outer diameters of the conductive shell 202 and the catheter shaft 204 to facilitate flush placement of a face of each of the electrodes 207i₄. In some embodiments, it may be desirable to have the face of each of the electrodes 207i extend above an outer diameter of the conductive shell 202 and the catheter shaft 204, or in non-contact sensing implementations, recessing the face of each of the electrodes 207i₄ below an outer diameter of the conductive shell 202 and the catheter shaft 204. [0055] In some embodiments, the flexible circuit 291_A may be supported by a backing structure 235 which helps to maintain the structural integrity of the flexible circuit in response to tissue contact.

[0056] FIG. 2C further shows a deformable member 230 of an optical force sensing system, where the ablation catheter tip assembly 200 is enabled for tissue contact force sensing (as discussed in more detail in relation to FIG. 2D). In various embodiments of the present disclosure, electrophysiology signals from the electrodes 207_I-4 may be used by controller circuity, in conjunction with force sensing measurements from the optical force sensing system, to optimize an ablation therapy.

[0057] As discussed above, flexible circuit 291A may be comprised of a multi-layer printed flexible circuit design which facilitates placement of electrodes on an outer surface of the printed flexible circuit and a plurality of thermocouples printed on internal conductive layers. As a result, electrophysiology signals from the electrodes may be sensed at a same location about the catheter shaft as temperature signals, where the thermocouples are positioned directly below electrodes.

[0058] In yet some other embodiments of the present disclosure, the thermocouples may be placed on an outer surface of the multi-layer printed flexible circuit between electrodes.

[0059] While the embodiment of FIGs. 2A-D envision routing the flexible circuit 291A at least partially through an irrigant lumen, various other possible routing paths are readily envisioned. For example, the flexible circuit may run proximally along an exterior of the catheter shaft 204, or within the catheter shaft (but outside of the irrigant lumen).

[0060] In various embodiments of the present disclosure the electrodes may be spot electrodes, also referred to as microelectrodes. The surface of these microelectrodes may be, for example, copper, gold-plated, Pt/Ir plated, or plated/coated with another material that provides superior electrograms and tissue impedance data, as well as superior durability. In various embodiments, the flexible circuits 291A_, B may include four electrodes each and one or more thermocouples, but the shape, size, and number of electrodes and/or thermocouples may vary from the embodiments shown, depending on specific design applications.

[0061] FIG. 2D is a perspective side view of a partial ablation catheter tip assembly 200 of FIG. 2A, sans catheter shaft 204 to further illustrate an optical force sensing system 248.

[0062] The partial ablation catheter tip assembly 200 includes a conductive tip 201 and conductive shell at a distal portion 205. The conductive shell includes a member 207 and a plurality of irrigant apertures 208 I-N. The conductive shell 202 is coupled to a distal end of a manifold 215. The manifold 215 may be comprised of, for example, a stainless steel alloy, MP35N (a cobalt chrome alloy), titanium alloy, or a composition thereof. The member 207 facilitates deformation of the flex tip in response to contact with tissue; more specifically, the member 207 deforms to increase surface contact with target tissue. The increased tissue surface contact improves outcomes for various diagnostics and therapies (e.g., tissue ablation). After contact with target tissue is complete, the member 207 returns to an un-deformed state. The distal tip may be coupled to the member 207 via an adhesive, weld, etc. A manifold 215, and an irrigation lumen 216 therein (as shown in FIG. 2C), extends through the structural member 230, delivering irrigant from the irrigation lumen to a dispersion chamber within the conductive shell 202

[0063] In various embodiments of the present disclosure, to limit the deformation of a structural member 230, partial ablation catheter tip assembly 200 may transmit a portion of a force exerted on the ablation electrode through the manifold 215 (bypassing structural member 230). The manifold 215 transmits the force to a catheter shaft that is coupled to a proximal end of the tip assembly 200 (as shown in FIGs. 2A-C).

[0064] Structural member 230 houses a plurality of fiber optic cables 240_I-3 that extend through grooves, for example groove 2331. In the present embodiment, the structural member 230 is divided into a plurality of segments along a longitudinal axis. The segments are bridged by flexure portions 2311-2, each flexure portion defining a neutral axis. Each of the neutral axes constitute a location within the respective flexure portions where the stress is zero when subjected to a pure bending moment in any direction.

[0065] In an optical force sensing system 248, fiber optic cables 240_I-3 may be disposed in grooves 233, respectively, such that the distal ends of the fiber optic cables terminate at the gaps of respective flexure portion 2311-2. As shown in FIGs. 2D, flexure portions 2311-2 define a semi-circular segment that intercepts an inner diameter of structural member 230. The flexure portions 2311-2 may be formed by one of the various ways available to an artisan, such as but not limited to sawing, laser cutting or electro-discharge machining (EDM).

[0066] When an optical force sensing system consistent with the above is assembled, one or more fiber optic cables 240 are mechanically coupled to structural member 230 via grooves 233. In some embodiments, each of the fiber optic cables may be communicatively coupled to a Fabry -Perot strain sensor within one of the gaps which form the flexure portions 2311-2. The Fabry-Perot strain sensor includes transmitting and reflecting elements on either side of the slots to define an interferometric gap. The free end of the transmitting element may be faced with a semi-reflecting surface, and the free end of the reflecting element may be faced with a semi- reflecting surface.

[0067] In some embodiments, structural member 230 may comprise a composition including a stainless steel alloy (or other metal alloy with characteristics including a high tensile strength, e.g., titanium), or platinum iridium (e.g., in a 90/10 ratio).

[0068] Further referring to the structural member 230, the structural member 230 is designed in such a way as to receive forces exerted on tip 201 and/or shell 202, and to absorb such force by deflecting and deforming in response thereto. Further, and as discussed in more detail above, the structural member 230 may incorporate a measurement device which facilitates measurement of the deflection/deformation of the deformable body which may be correlated with the force exerted on the distal portion 205 of the catheter 200 and communicated with a clinician. Knowledge of a force exerted on the distal portion 205 of the catheter may be useful for a number of different cardiovascular operations; for example, during a myocardial tissue ablation therapy it is desirable to know a contact force exerted by the distal portion of the catheter on target tissue as tissue necrosis time is based on energy transferred between the catheter and tissue, and the extent of tissue contact.

[0069] In the various catheter tip assemblies disclosed herein, various electronic components in the catheter tip are necessary to facilitate desired functionality. As discussed in more detail above, the catheter tip may include, for example, one or more radio-frequency ablation electrodes, one or more electrodes, and/or a plurality of thermocouples. All of these electronic components must be communicatively coupled to a catheter controller system at a proximal end of the catheter (as discussed above in reference to FIG. 1). Prior art ablation catheter systems utilize individual lead wires, extending the length of the catheter shaft, to facilitate communication between the various distal tip components and the catheter control system. Aspects of the present disclosure are directed to reduced catheter assembly complexity by using one or more flexible circuits which extend at least a portion of the length of the catheter shaft, and communicatively couple the electronic components to the catheter control system.

[0070] Figure 2E is a cross-sectional side view of a proximal portion 210 of the ablation catheter tip assembly 200 of Figure 2A which facilitates an understanding of irrigant flow through the proximal portion of the ablation catheter tip assembly. The irrigant flows from an irrigant source through a catheter handle and into a central lumen of catheter shaft 204. The central lumen delivers the irrigant to a distal end of the catheter shaft 204. Upon arriving at the distal end of the catheter shaft, the irrigant transitions into a smaller diameter irrigant lumen 216 of manifold 215 via end cap 251. The manifold 215 delivers irrigant to a proximal end of conductive shell 202 (as shown in FIG. 2C), the irrigant is then circumferentially distributed through irrigant apertures 208 I-N in the conductive shell 202 via positive pressure.

[0071] A structural member 230 may be coupled at a distal end to a distal end of manifold 215, and at a proximal end to both the manifold 215 and an end cap 251. In some embodiments, the end cap may be made of platinum, titanium alloy, stainless steel alloy, MP35N (a cobalt chrome alloy), or a combination thereof. Once the tip assembly 200 is complete, the structural member 230 may be further coupled at a proximal end to a catheter shaft 204, that extends proximally to a catheter handle. The structural member 230 is designed in such a way as to receive forces exerted on a distal portion 205 of the catheter tip assembly 200 and to absorb such force by deflecting and deforming in response thereto. Further, and as discussed in more detail above, the structural member 230 may incorporate an optical force sensing system which facilitates measurement of the deflection/deformation of the deformable body. This deflection/deformation may be correlated with the force exerted on a distal portion 205 of the tip assembly 200, and communicated to a clinician.

[0072] As shown in FIG. 2E, flexible circuits 291_A-B are routed through an irrigant lumen 216 of manifold 215. Similarly, irrigant delivered to (and through) conductive shell 207 (as shown in FIG. 2D) flows through the irrigant lumen 216 of the manifold 215. First, however, the irrigant travels through end cap 251 via irrigant aperture 251c into the irrigant lumen 216. The irrigant then flows along a length of the irrigant lumen and around the one or more flexible circuits into the conductive shell, before exiting through irrigant apertures 208_I-N and 208’ 1-4 (as shown in FIGs. 2A-D).

[0073] As shown in FIG. 2E, flexible circuits 291_A-B extend proximally through irrigant lumen 216 of manifold 215, through auxiliary apertures 251_A, B in end cap 251, and into an interior lumen of catheter shaft 204. The flexible circuits 291_A-B may extend a length of the catheter shaft, or otherwise, may be communicatively coupled to another flexible circuit or a plurality of lead wires somewhere within the catheter shaft. In such embodiments, the flexible circuits 291A-B may include one or more connectors (or solder pads) at proximal ends of the respective circuits which facilitate electrical coupling to another flexible circuit or lead wires. [0074] In various embodiments, the flexible circuits 291A-B are integrated into a single flexible circuit in the tip assembly 200, and include a plurality of thermocouples with are placed into (direct or indirect) thermal contact with the conductive shell 207 to conduct high-thermal sensitivity monitoring during an ablation therapy. In yet further embodiments, the flexible circuit in the tip assembly includes one or more microelectrodes which facilitate electrophysiology monitoring of tissue in contact with the conductive shell and/or conductive tip 201.

[0075] In yet further more specific embodiments of the present disclosure, thermocouples positioned on flexible circuit 291_A may output an electrical signal indicative of a temperature which may be used by controller circuitry to compensate for temperature variation which can affect a distance measurement of fiber optics on structural member 230. For example, extended periods of ablation therapy may warm the structural member 230 and cause thermal expansion thereof. The thermal expansion changes a gap across a flexure portion in the structural member where an optical distance measurement is conducted. As a result, the controller circuitry may interpret the thermal expansion across the flexure portion as a force being exerted on a distal tip of the catheter. By compensating for the thermal expansion of the structural member, via the thermocouple signal output, erroneous force readings may be mitigated.

[0076] Figure 3 is a top view of a pair of flexible electronic circuits 3031-2 (also referred to as a flexible circuit, or flex circuit). In various embodiments, the flexible circuits 3031-2 may be installed within a catheter tip assembly of a catheter system, instead of utilizing individually wired temperature sensors and electrodes. By consolidating various wire leads into one or more flexible circuits, or even one or more flexible circuits plus a few wire leads, the cost, complexity, and manufacturing assembly time associated with such catheter tip assemblies may be greatly reduced.

[0077] Flexible circuits 3031-2 may include one or more connectors 392_I-2 located at a proximal end of the flexible circuits to facilitate communicatively coupling the flexible circuits to other flexible circuits, lead wires, etc. For example, where the catheter tip is completed in sub-assembly form prior to installation with a catheter shaft sub-assembly, the connectors 392 may extend from the catheter tip sub-assembly to facilitate coupling to another flexible circuit extending from the catheter shaft sub-assembly. To further facilitate assembly, the connectors 392 may be electrically coupled to the flexible circuit(s) of the catheter shaft sub-assembly via an electrical connector. Alternatively, solder pads of the respective flexible circuits may be soldered to one another. The use of flexible circuits may also further facilitate automation of the catheter assembly process.

[0078] In Fig. 3, electrical signals from thermocouples and/or electrodes on flexible circuits 3031-2 are isolated from one another by extending traces 396 which extend proximally to solder pads 393_I-N on connectors 392i and 392₂. This example flexible circuit routing mitigates electrical and electromagnetic cross-talk (interference) between the un-shielded electrical traces. The various electrical traces on the printed flexible circuits 391 form a communication pathway. [0079] In various embodiments, flexible circuits 303_I-2 may further include one or more solder pads 306_I-4 and 307i-₄(for electrically coupling to electrodes which are soldered thereto), or alternatively 306_I-4 and 307_I-4 may be printed electrodes which are printed directly to the printed flexible circuits 391. These electrodes, when capacitively coupled to tissue, may collect electrophysiology data related to the tissue (e.g., myocardial tissue). This electrophysiology data is then communicated via traces 396 to one or more solder pads 393 on the connectors 392 of the flexible circuits.

[0080] The flexible circuits 3031-2 may include bonding locations that facilitate coupling to the rest of an ablation catheter tip assembly. It is to be understood that various coupling means may be utilized, including: ultrasonic welding, fasteners, adhesives, friction and compression fits, etc. to achieve coupling of the flexible circuits 391 to the rest of the tip assembly.

[0081] The placement of the flexible circuits 303I-2 in the tip assembly facilitate direct contact between a face of an electrode and tissue in contact with a distal portion of the ablation catheter. In various embodiments, thermocouples may be printed on an inner layer of the printed flexible circuit 391 (such as directly below one of the electrodes), but still capable of quick thermal response as the layers of the printed flexible circuit exhibit high thermal transmissivity. Such quick thermal response of the thermocouples is desirable to achieve low lag control inputs. Slow thermal response of the thermocouples may cause over ablation of tissue, steam pops, charring on the catheter, etc. [0082] As discussed in more detail above, when flexible circuit 3031 is wrapped around an exterior surface of a catheter, thermocouples and electrodes on flex circuit 303i form a first circumferentially-extending ring positioned near a tip of the catheter. Similarly, thermocouples and electrodes on flexible circuit 303₂ form a second circumferentially-extending ring positioned near a proximal end of the tip.

[0083] It is to be understood that various flexible circuit layouts may be utilized to facilitate application specific design constraints in various flexible circuit 303 designs, consistent with the present disclosure. For example, to limit flexible circuit area, additional PCB layers may be added where the Z-dimension of a given application allows. Similarly, more or less connectors 392 and/or pads 393 may be implemented where necessary for additional signal bandwidth. In yet further embodiments, the flexible circuits 303 may include various signal conditioning circuitry ( e.g ., analog-to-digital converter(s), noise filters, etc.). Once the signal is digitized, one or more electrode/thermocouple signals may be transmitted along the same signal pathway, further reducing communication pathways, and flex circuit real estate required to communicate the signals along a length of the catheter shaft.

[0084] While FIG. 3 is presented with two separate flexible circuits, a skilled artisan would readily appreciate that a single flexible circuit may also be utilized to accomplish the goals of the dual flexible circuit embodiment.

[0085] In various embodiments, the flexible circuits 391 may include three or more layers: a copper layer, an intermediate polyimide layer, and a constantan layer opposite the copper layer. Each of the thermocouples may be formed by drilling a via through the copper, polyimide, and constantan layers, and through plating the via with copper. Various thermocouple designs and manufacturing methods are well known in the art and may be applied hereto. Either side of the thermocouple is then electrically coupled to a trace on its respective layer. The voltage across the two traces may be compared, and the resulting voltage change is indicative of a temperature experienced by the thermocouple. In various applications, including ablation therapies, as the thermocouples are in thermally transmissive communication with the ablation electrode and/or tissue being ablated, the efficacy of an ablation therapy may be surmised by a clinician and/or controller circuity (at least in part) in view of the voltage across the one or more thermocouples. [0086] In the present embodiment, flexible circuits 303 are designed to facilitate individual addressability of each of the thermocouples and electrodes 306i and 307i . In more simplified embodiments, the thermocouples may be electrically coupled in parallel to effectively facilitate temperature averaging of the thermocouples, and to minimize printed flexible circuit size requirements. In more specific embodiments, distal thermocouples and proximal thermocouples may be electrically coupled in two distinct circuits to facilitate temperature averaging about a distal tip and immediately proximal the ablation electrode. Such embodiments may be particularly useful in applications where determining a tissue contact point along a circumference of the ablation catheter is not necessary. The present embodiment may also limit the effect of minute hot zones on an ablation control system.

[0087] As further shown in Fig. 3, each of the plurality of electrodes 306_I-4 of flexible circuit 3031 are positioned on protrusions extending from a body of the flexible circuit 391. Each of the protrusions facilitate positive positioning of the flexible circuit when assembled to a conductive tip (within a trench in the outer surface), thereby preventing movement of the flexible circuit relative to the conductive tip. Moreover, the protrusions facilitate routing each of the electrodes from an internal cavity to an external surface of the conductive tip via one or more apertures extending through at least one of the conductive tip and conductive shell. To facilitate positive placement of the plurality of electrodes 307I-4 of flexible circuit 3032, a distal end of the flexible circuit is circumferentially wrapped about an outer surface of the distal tip assembly within a trench between the catheter shaft and conductive shell. To further facilitate positive coupling of the flexible circuits on an exterior of the distal tip assembly, adhesive may be applied between the flexible circuits and the rest of the tip assembly, a re-flow process may be applied over the entire tip assembly, among other methods.

[0088] As each electrode forms only one half of a circuit, each electrode need only one trace 396 extending to a connector 392 of the flexible circuits. The electrical signal from each spot electrode is compared and analyzed to detect electrophysiological characteristics indicative of medical conditions, such as, atrial fibrillation. Similarly, during and after treatment, the electrodes may be used to conduct diagnostics and determine a treatment efficacy.

[0089] To further reduce traces in the flexible circuits 303, all of the cold junctions of the thermocouples may be electrically interconnected, and effectively function as a common ground. By electrically interconnecting each of the electrical traces extending from the cold junctions, the number of common connector pads 393I-N may be greatly reduced. As is envisioned in the present embodiment, the common ground for all of the thermocouples would require only a single connector pad, reducing flexible circuit 391 size and complexity.

[0090] In further embodiments of the present embodiment shown in FIG. 3, thermocouples may be printed on innerlayers of the printed flexible circuit and may be communicatively coupled to solders pads on a back-side of the connectors 392 via traces extending along one or more of the printed flexible circuit layers.

[0091] Figure 4 A is a side view of an ablation catheter tip assembly 400, and Figure 4B is a perspective side view of the ablation catheter tip assembly 400 of Figure 4A. In the embodiment of FIGs. 4A/B, a flex circuit located proximal to conductive shell 402 and distal of catheter shaft 404 is assembled under a thermally conductive ring 440 such as an industrial diamond ring. The thermally conductive ring 440 facilitates efficient heat removal from a “hot zone” of the conductive shell 402 during ablation, and also rapid thermal transfer to the thermocouples for low-lag temperature measurement. Other thermally conductive but electrically insulative materials could be used. In the present embodiment, the flex circuit would not utilize microelectrodes, as the flex circuit would be positioned underneath the ring 440. The flex circuit may be either in direct contact with the conductive ring to facilitate optimum thermal transfer, or there could be a thermally conductive material between the flex circuit and the ring to facilitate thermal transfer from tissue in contact with the catheter to the thermocouples on the flex circuit. [0092] The flex circuit of the present embodiment may have a similar routing to that illustrated in FIG. 2C.

[0093] One alternative to the embodiment disclosed in FIGs. 4A/B would be to utilize separate thermocouples positioned under the conductive ring 440, sans a flexible circuit. In such an embodiment, the thermocouples may be directly coupled to the conductive ring 440 to facilitate thermal transfer, and communicatively coupled to lead wires which are coupled to controller circuity at a proximal end of the catheter system.

[0094] In various embodiments of the catheter tip assemblies disclosed herein, the catheter tip assemblies may also include a plurality of spot electrodes on a conductive shell thereof which facilitate electrophysiology mapping of tissue, such as myocardial tissue, in (near) contact with the shell. In more specific embodiments, the plurality of spot electrodes may be placed across the shell in such a manner as to facilitate Orientation Independent Algorithms which enhance electrophysiology mapping of the target tissue and is further disclosed in United States application no. 15/152,496, filed 11 May 2016, United States application no. 14/782,134, filed 7 May 2014, United States application no. 15/118,524, filed 25 February 2015, United States application no. 15/118,522, filed 25 February 2015, and United States application no.

62/485,875, filed 14 April 2017, all of which are now pending, and are incorporated by reference as though fully disclosed herein.

[0095] While various embodiments of the present disclosure, including FIGs. 2-4, are directed to ablation catheter tips including two rings of 4 radially-disposed thermal sensors, the invention is not limited to such an eight-sensor configuration. Various other configurations are readily envisioned.

[0096] It is to be understood that while an irrigated ablation catheter tip is illustrated in various embodiments of the present disclosure, the design of the structural assembly (including structural member, manifold, and end cap) is modular and may facilitate the fitting of various catheter tips (e.g., rigid, flex, and other advanced irrigation tips).

[0097] Applicant further envisions utilizing catheters comprising various segmented tip designs with the ablation catheter system described above. Example tip configurations are disclosed in United States patent application no. 61/896,304, filed 28 October 2013, and in related international patent application no. PCT/US2014/062562, filed 28 October 2014 and published 07 May 2015 in English as international publication no. WO 2015/065966 A2, both of which are hereby incorporated by reference as though fully set forth herein.

[0098] Although several embodiments 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 present disclosure. 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 may be made without departing from the present teachings. The foregoing description and following claims are intended to cover all such modifications and variations. [0099] Various embodiments are described herein of various apparatuses, systems, and methods. Numerous specific details are set forth to provide a thorough understanding of the overall structure, function, manufacture, and use of the embodiments as described in the specification and illustrated in the accompanying drawings. It will be understood by those skilled in the art, however, that the embodiments may be practiced without such specific details. In other instances, well-known operations, components, and elements have not been described in detail so as not to obscure the embodiments described in the specification. Those of ordinary skill in the art will understand that the embodiments described and illustrated herein are non-limiting examples, and thus it can be appreciated that the specific structural and functional details disclosed herein may be representative and do not necessarily limit the scope of the embodiments, the scope of which is defined solely by the appended claims.

[00100] Reference throughout the specification to “various embodiments,” “some embodiments,” “one embodiment,” “an embodiment,” or the like, means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in various embodiments,” “in some embodiments,” “in one embodiment,” “in an embodiment,” or the like, in places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Thus, the particular features, structures, or characteristics illustrated or described in connection with one embodiment may be combined, in whole or in part, with the features structures, or characteristics of one or more other embodiments without limitation. [00101] It will be appreciated that the terms “proximal” and “distal” may be used throughout the specification with reference to a clinician manipulating one end of an instrument used to treat a patient. The term “proximal” refers to the portion of the instrument closest to the clinician and the term “distal” refers to the portion located furthest from the clinician. It will be further appreciated that for conciseness and clarity, spatial terms such as “vertical,” “horizontal,” “up,” and “down” may be used herein with respect to the illustrated embodiments. However, surgical instruments may be used in many orientations and positions, and these terms are not intended to be limiting and absolute. [00102] Any patent, publication, or other disclosure material, in whole or in part, that is said to be incorporated by reference herein is incorporated herein only to the extent that the incorporated materials does not conflict with existing definitions, statements, or other disclosure material set forth in this disclosure. As such, and to the extent necessary, the disclosure as explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material set forth herein will only be incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material.

Claims

CLAIMS What is claimed is:

1. A high-thermal-sensitivity ablation catheter tip, the tip comprising: an ablation electrode configured and arranged to deliver an ablation therapy to tissue in contact with or in close proximity thereto; and a flexible electronic circuit proximal the ablation electrode, wherein the flexible electronic circuit includes a plurality of electrodes configured and arranged to sense electrophysiology characteristics of the tissue in contact with or in close proximity to the ablation electrode.

2. The high-thermal-sensitivity ablation catheter tip of claim 1, wherein the ablation electrode and the flexible electronic circuit are in contact with one another.

3. The high-thermal-sensitivity ablation catheter tip of claim 1, further including a catheter shaft coupled to a proximal end of the flexible electronic circuit and extending proximally to a catheter handle, wherein the flexible electronic circuit extends circumferentially about an outer diameter of the ablation catheter tip, and wherein a proximal end of the flexible electronic circuit extends radially inward from the circumferential portion of the flexible electronic circuit into an interior of the catheter shaft, and extends proximally along a length of the catheter shaft, the flexible electronic circuit configured and arranged to communicatively couple the plurality of electrodes with controller circuitry of an ablation catheter.

4. The high-thermal-sensitivity ablation catheter tip of claim 1, wherein the flexible electronic circuitry includes a plurality of thermocouples, the thermocouples configured and arranged to sense a temperature of the tissue in contact with or in close proximity to the ablation electrode and transmit an electrical signal indicative of the sensed temperature to controller circuitry of an ablation catheter.

5. The high-thermal-sensitivity ablation catheter tip of claim 1, wherein the plurality of electrodes are further configured and arranged to sense the temperature of the tissue in contact with the ablation electrode.

6. The high-thermal-sensitivity ablation catheter tip of claim 1, wherein the ablation electrode includes a conductive tip and a conductive shell, at least the conductive shell including irrigant apertures extending therethrough, the irrigant apertures configured and arranged for irrigant distribution between the ablation electrode and the tissue receiving an ablation therapy, wherein the high-thermal-sensitivity ablation catheter tip further includes a manifold including an irrigation lumen extending through a longitudinal axis of the manifold, the irrigation lumen configured and arranged to deliver irrigant into the dispersion chamber, and wherein the flexible electronic circuit extends through at least a portion of the irrigation lumen.

7. The high-thermal-sensitivity ablation catheter tip of claim 1, further including a structural member coupled to a proximal end of the ablation electrode, the structural member configured and arranged to deflect in response to a force exerted on the ablation electrode.

8. The high-thermal-sensitivity ablation catheter tip of claim 1, further including a second flexible electronic circuit coupled to a distal portion of the ablation electrode, the second flexible electronic circuit including a second plurality of electrodes distributed circumferentially about an exterior surface of the ablation electrode.

9. The high-thermal-sensitivity ablation catheter tip of claim 8, wherein the second flexible electronic circuit further includes a second plurality of thermocouples, the thermocouples configured and arranged to sense a temperature of the tissue in contact with or in close proximity to the ablation electrode.

10. The high-thermal-sensitivity ablation catheter tip of claim 9, wherein the first and second plurality of electrodes are electrically isolated from the ablation electrode.

11. The high-thermal-sensitivity ablation catheter tip of claim 9, wherein the first and second plurality of thermocouples are configured in two circumferential rings about the ablation catheter tip, the first circumferential ring longitudinally offset from the second circumferential ring.

12. The high-thermal-sensitivity ablation catheter tip of claim 8, wherein the second plurality of electrodes are spot electrodes, and the spot electrodes and one or more portions of the second flexible circuit extend through apertures in the ablation electrode, each of the spot electrodes being electrically insulated from the ablation electrode to reduce signal interference between the ablation electrode and the spot electrodes.

13. A high-thermal-sensitivity ablation catheter tip, the tip comprising: an ablation electrode configured and arranged to deliver an ablation therapy to tissue in contact with or in close proximity thereto; a flexible electronic circuit proximal the ablation electrode and including a plurality of thermocouples which are circumferentially distributed around the ablation catheter tip; and a thermally conductive ring circumferentially encompassing the flexible electronic circuit, the ring configured and arranged to draw heat away from a proximal end of the ablation electrode.

14. The high-thermal-sensitivity ablation catheter tip of claim 13, wherein the plurality of thermocouples are configured and arranged to sense a temperature of the tissue and transmit an electrical signal indicative of the sensed temperature to controller circuitry of an ablation catheter, wherein the ring is electrically insulative and is configured and arranged to electrically insulate the plurality of thermocouples from a current emitted from the ablation electrode, while heat from the ablation electrode and tissue in contact therewith, or in close proximity to, is readily transferred to the thermocouples via the ring.

15. The high-thermal-sensitivity ablation catheter tip of claim 13, further including a catheter shaft coupled to a proximal end of the flexible electronic circuit and extending proximally to a catheter handle, wherein the flexible electronic circuit extends circumferentially about an outer diameter of the ablation catheter tip, and wherein a proximal end of the flexible electronic circuit extends radially inward from the circumferential portion of the flexible electronic circuit into an interior of the catheter shaft, and extends proximally along a length of the catheter shaft, the flexible electronic circuit configured and arranged to communicatively couple the plurality of thermocouples with controller circuitry of an ablation catheter.

16. The high-thermal-sensitivity ablation catheter tip of claim 13, the conductive shell including irrigant apertures extending therethrough, the irrigant apertures configured and arranged for irrigant distribution; wherein the high-thermal-sensitivity ablation catheter tip further includes a manifold including an irrigation lumen extending through a longitudinal axis of the manifold, the irrigation lumen configured and arranged to deliver irrigant to the irrigant apertures, and wherein the flexible electronic circuit extends through at least a portion of the irrigation lumen.

17. The high-thermal-sensitivity ablation catheter tip of claim 13, further including a second flexible electronic circuit coupled to a distal portion of the ablation electrode, the second flexible electronic circuit including a second plurality of thermocouples distributed circumferentially about an exterior surface of the ablation electrode.

18. The high-thermal-sensitivity ablation catheter tip of claim 17, wherein the second flexible electronic circuit further includes a first plurality of electrodes.

19. The high-thermal-sensitivity ablation catheter tip of claim 17, wherein the first and second plurality of thermocouples are electrically isolated from the ablation electrode.

20. The high-thermal-sensitivity ablation catheter tip of claim 17, wherein the first and second plurality of thermocouples are configured in two circumferential rings about the ablation catheter tip, the first circumferential ring longitudinally offset from the second circumferential ring.

21. The high-thermal-sensitivity ablation catheter tip of claim 18, wherein the first plurality of electrodes are spot electrodes, and the spot electrodes and one or more portions of the second flexible circuit extend through apertures in the ablation electrode, each of the spot electrodes are electrically insulated from the ablation electrode to reduce signal interference between the ablation electrode and the spot electrodes.