Patent Publication Number: US-2021169562-A1

Title: Intravascular needle with flex circuit

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority under the Paris Convention as well as 35 U.S.C. § § 119 and 120 to prior filed U.S. Provisional Patent Application No. 62/943,552 filed on Dec. 4, 2019 which is hereby incorporated by reference as set forth in full herein. 
    
    
     FIELD 
     The present invention generally relates to intravascular catheter systems, and more particularly, to electrodes for intravascular ablation and/or diagnostics. 
     BACKGROUND 
     Various catheters are available that deliver electrodes to cardiac or other tissues of the body for the purpose of ablation, diagnostics, and other functions to aid in medical treatments. 
     Electrodes used for ablation can be configured to deliver concentrated radiofrequency (RF) current to tissue to create thermal injury of tissue in contact with the electrode. Insufficient heating can result in an insufficiently sized lesion while overheating of the electrode can cause evaporation of tissue or blood water and steam bubble formation that can uncontrollably and undesirably rupture tissue. Accurate temperature measurement during ablation can be challenging due to placement of thermocouples in relation to the electrodes. In some applications, it can be advantageous to puncture tissue so that an electrode can be placed within the tissue; however, abrupt electrode geometry shaped to puncture tissue can lead to non-uniform current distribution during ablation and therefore hot spots. To avoid inadvertently puncturing tissue by a sharp electrode, the electrode can be sheathed during intravascular delivery; however, it can be difficult to ascertain whether the electrode is properly sheathed when the electrode is in a patient. Applicant therefore recognizes a need for improved intravascular ablation tools and methods. 
     Electrodes used for diagnostics are typically positioned as rings spaced along an atraumatic shaft at a distal end of a catheter. The atraumatic shaft can be shaped such that the rings can contact tissue. In some applications, such diagnostic catheters can be used to effectively map intravascular systems and the heart. For treatment of arrhythmias, for instance, catheter delivered electrodes can be used to map electrical properties from within the heart to locate conduction paths of signals causing the arrhythmia. Challenges associated with diagnostic catheter electrodes include increasing electrode count and capturing sub-dermal data. Increasing electrode count means increasing number of electrodes and wiring to each electrode which can increase the bulk of a diagnostic catheter. A bulkier catheter can become less flexible and/or larger in diameter, increasing difficulty of delivery and positioning of the catheter during a procedure. Sub-dermal data can be captured by a structure similar to the ablation needle disclosed above; however, the needle structure includes only a singular electrode (the needle). Further, the needle structure is preferably sheathed during delivery to avoid inadvertent puncturing of tissue, and a sheath further increases the bulk of the diagnostic catheter. Applicant therefore recognizes a need for improved intravascular diagnostic electrode tools and methods. 
     SUMMARY 
     There is provided, in accordance with some embodiments of the present disclosure a device for lancing intravascular tissue that includes a tubular electrical circuit and a sharp end. The circuit has an outer surface disposed about a longitudinal axis to define a tubular shape extending along the longitudinal axis from a first end of the circuit to a proximal portion of the circuit. The circuit includes an electrically insulative substrate film, a patterned layer including electrically conductive traces that is disposed over the substrate film, an electrically insulative isolating film including one or more vias therethrough that is disposed over the patterned layer, and one or more electrodes disposed over the isolating film and on the outer surface of the tubular shape. The sharp end is affixed approximate the first end of the tubular shape of the circuit. 
     In some embodiments, the device includes a needle surrounded by the circuit and affixed to the circuit such that the sharp end of the device includes the tip of the needle. In some embodiments, each of the one or more electrodes is electrically isolated from the needle. 
     In some embodiments, the circuit has a pointed tip near the first end of the tubular shape such that the sharp end includes the pointed tip. Embodiments including the circuit with the pointed tip may or may not include a needle, metal sheet, or other structural support to maintain the tubular shape during usage of the device. In some embodiments, the tubular shape of the circuit has columnar rigidity sufficient to lance intravascular tissue with the pointed tip without relying on additional structural support to the tubular shaped circuit. 
     In some embodiments, the electrically insulative substrate film forms a lumen through the tubular shape and is positioned on an inner surface of the lumen. The lumen through the tubular shape can serve as a passageway for irrigation fluid without an additional structure between the insulative substrate and the irrigation passageway. 
     In some embodiments, the circuit further includes a metal sheet under the electrically insulative substrate. The metal sheet includes a pointed tip approximate the first end of the tubular circuit. The sharp end includes the pointed tip of the metal sheet. The metal sheet is disposed on an inner surface of the tubular shape. The tubular shape includes the metal sheet, and the tubular shape has columnar rigidity sufficient to lance intravascular tissue. 
     In some embodiments, at least one of the one or more electrodes respectively includes a gold band encircling the tubular shape. 
     In some embodiments, the circuit further includes solder pads each electrically connected to a respective trace of the electrically conductive traces on the patterned layer. The one or more vias are positioned such that the one or more electrodes are each electrically connected to a respective trace. 
     In some embodiments, the solder pads are disposed at the proximal portion of the circuit. 
     In some embodiments, the device further includes a sheath. The sheath surrounds the electrical circuit and the sharp end. The electrical circuit and sharp end are slidable to extend the sharp end out of the sheath. 
     In some embodiments, the sharp end is electrically isolated from the one or more electrodes. 
     In some embodiments, the device includes more than one electrode and more than one via. Each electrode is electrically connected through a respective via to a respective electrically conductive trace on the patterned layer. Each electrode is electrically isolated from every other electrode. 
     In some embodiments, the circuit further includes one or more thermocouple junctions. 
     In some embodiments, the device includes a thermocouple junction positioned at a via. The thermocouple junction includes a portion of an electrode and a portion of a trace on the patterned layer, the portion of the electrode and the portion of the trace being in electrical contact with each other. In some embodiments, the electrode of the thermocouple includes gold, and the trace of the thermocouple includes constantan. 
     In some embodiments, the device includes a thermocouple junction residing in the patterned layer. The thermocouple junction includes respective portions of two traces on the patterned layer such the respective portions of the two traces are in electrical contact. 
     In some embodiments, the device includes a thermocouple junction and a needle having an outer surface. The thermocouple junction is electrically isolated from the needle. The thermocouple junction is positioned over the outer surface of the needle. 
     In some embodiments, the device includes a pure gold electrode having a thickness of approximately 0.001 inches (about 25 micrometers). 
     In some embodiments, the device has more than one electrode and more than one thermocouple junction. Each thermocouple junction is positioned to be heated by a respective electrode. Some or all of the thermocouple junctions include a portion of the respective electrode. Additionally, or alternatively, some or all of the thermocouple junctions are each respectively positioned in the patterned layer, below the respective electrode and electrically isolated from the respective electrode. 
     In some embodiments, the device further includes a navigation sensor positioned to detect a movement of one or more electrodes. 
     In some embodiments, the navigation sensor is positioned to detect movement, in relation to the navigation sensor, of at least two electrodes of the one or more electrodes. 
     In some embodiments, the device further includes a catheter having a distal end, a needle assembly including the circuit and the sharp end, and a navigation sensor. The needle assembly is translatable in one dimension in relation to the navigation sensor. The navigation sensor is affixed near the distal end of the catheter. The navigation sensor is positioned to detect movement, in relation to the navigation sensor, of one or more electrodes. 
     In some embodiments, the device includes more than one electrode, more than one via, and more than one electrically conductive trace. The circuit further includes solder pads. Each of the electrodes are electrically connected through a respective via to a respective trace. The solder pads are each electrically connected to a respective electrically conductive trace. 
     In some embodiments, at least one of the electrodes is electrically isolated from every other electrode. 
     In some embodiments, one or more electrodes are configured to measure a voltage and/or impedance. 
     In some embodiments, the electrodes include ring electrodes, each ring electrode circumscribing the tubular shape of the circuit. 
     In some embodiments, ring electrodes are spaced a predetermined distance from the sharp end. Each ring electrode is isolated, at the outer surface of the tubular shape defined by the circuit, from every other ring electrode. 
     In some embodiments, ring electrodes are confined to a distance of approximately 9 mm as measured from a tip of the sharp end. 
     In some embodiments, the circuit includes about 6 ring electrodes to about 10 ring electrodes. 
     In some embodiments, ring electrodes are spaced, with an edge-to-edge spacing to each neighboring ring electrode with a spacing of about 2 mm to about 4 mm. 
     There is further provided, in accordance with some embodiments of the present disclosure, a system including a circuit, a sharp end, a navigation sensor, and a processing device. The circuit defines an outer surface disposed about a longitudinal axis to define a tubular shape extending along the longitudinal axis from a first end of the circuit to a proximal portion of the circuit. The sharp end is affixed near the first end of the tubular shape. The circuit includes an electrically insulative substrate film, a patterned layer disposed over the substrate film, an electrically insulative isolating film disposed over the patterned layer, and a plurality electrodes disposed over the isolating film and on the outer surface of the tubular shape. The patterned layer includes electrically conductive traces. The electrically insulative isolating film includes one or more vias therethrough. The navigation sensor is positioned to detect movement, in relation to the navigation sensor, of an electrode of the one or more electrodes. The processing device is configured to extract electrical measurements from the plurality of electrodes and determine, using the navigation sensor, a position of each of the plurality of electrodes in relation to intracardial tissue. 
     In some embodiments, the one or more electrodes include a plurality of ring electrodes. The processing device is further configured to determine impedance of the intracardial tissue at multiple depths of the tissue in response to lancing the intracardial tissue with the sharp end of the device and inserting the plurality of ring electrodes into the intracardial tissue. 
     In some embodiments, the system includes a catheter, conductive wires, and a radio frequency generator. The conductive wires are each respectively electrically connected to a respective electrically conductive trace. The conductive wires extend through the catheter. The radio frequency generator is electrically connected to at least one of the conductive wires. 
     There is further provided, in accordance with some embodiments of the present disclosure, a system including a circuit, a sharp end, a catheter, conductive wires, and a radio frequency generator. The circuit defines a tubular shape having an outer surface disposed about a longitudinal axis. The tubular shape extends along the longitudinal axis from a first end of the circuit to a proximal portion of the circuit. The sharp end is affixed near the first end of the tubular shape defined by the circuit. The circuit includes an electrically insulative substrate film, a patterned layer disposed over the substrate film, an electrically insulative isolating film disposed over the patterned layer, and a plurality electrodes disposed over the isolating film and on the outer surface of the tubular shape. The patterned layer includes electrically conductive traces. The insulative isolating film disposed over the patterned layer includes one or more vias therethrough. The conductive wires are each respectively electrically connected to a respective electrically conductive trace. The conductive wires extend through the catheter. The radio frequency generator is electrically connected to at least one of the conductive wires. 
     In some embodiments, each respective electrically conductive trace is further electrically connected to a respective electrode. The radio frequency generator, and potentially multiple radio frequency generators, are electrically connected to one or more of the conductive wires. The one or more radio frequency generators are thereby each electrically connected to a respective electrode by way of the connection of the RF generator(s) to the conductive wire(s) and the connection of the conductive wire(s) to one or more electrodes. 
     In some embodiments, the system includes an electrical measurement tool electrically connected to a first portion of the plurality of electrodes while the one or more radio frequency generators is electrically connected to a second portion of the plurality of electrodes. The electrical measurement tool includes a voltmeter, an ohmmeter, and/or an ammeter. 
     There is further provided, in accordance with some embodiments of the present disclosure, an ablation tool having a sharp end and an ablation electrode electrically isolated from the sharp end. 
     There is further provided, in accordance with some embodiments of the present disclosure, an ablation tool having an ablation electrode and a thermocouple that includes a portion of the ablation electrode. 
     There is further provided, in accordance with some embodiments of the present disclosure, a system including a catheter, a navigation sensor, and a needle assembly. The navigation sensor is positioned near the distal end of the catheter. The needle assembly includes an electrode thereon and a sharp end. The needle assembly is translatable in one dimension in relation to the navigation sensor. The needle assembly is translatable to move the sharp end out of the catheter through the distal end of the catheter. The navigation sensor is positioned to detect movement of the electrode in relation to the navigation sensor. 
     There is further provided, in accordance with some embodiments of the present disclosure, a method of intravascular treatment, the method including one or more of the following steps: delivering an electrode needle assembly intravascularly via a catheter, lancing tissue in or around the heart with the electrode needle assembly, and moving a first electrode of the electrode needle assembly to a first depth within the tissue while moving a second electrode of the electrode needle assembly to a position above the tissue or at a second depth shallower than the first depth. 
     In some embodiments, the method further includes detecting, by the first electrode, a first electrical signal at the first depth in the tissue. The first electrical signal is indicative of at least one of a tissue voltage and a tissue impendence. 
     In some embodiments, the method further includes applying a radio frequency electrical signal to at least one of the first electrode and the second electrode. 
     In some embodiments, the method further includes infusing into the tissue an electrically-conductive fluid via a lumen in the electrode needle assembly while the first electrode is positioned at the first depth. 
     In some embodiments, the method further includes positioning the electrode needle assembly, while sheathed, in or around the heart, positioning a navigation sensor in or around the heart, unsheathing the electrode needle assembly, while positioned in or around the heart, and detecting, by the navigation sensor, movement of at least one of the first electrode and the second electrode as a result of the unsheathing of the electrode needle assembly. 
     In some embodiments, the method further includes sensing a temperature approximate at least one of the first electrode and the second electrode. 
     There is further provided, in accordance with some embodiments of the present disclosure, a method for ablating tissue in or around the heart, the method including one or more of the following steps: delivering an electrode needle assembly intravascularly via a catheter, lancing tissue in or around the heart with a sharp end of the electrode needle assembly, moving, into the tissue, an electrode electrically isolated from the sharp end, and ablating the tissue by applying electrical energy to the electrode. 
     In some embodiments, the step of ablating the tissue by applying electrical energy to the electrode further includes delivering electrical current from an annular surface of the electrode to the tissue such that the electrical current comprises a substantially uniform current density across the annular surface. 
     There is further provided, in accordance with some embodiments of the present disclosure, a method for constructing a device for lancing intravascular tissue, the method including one or more of the following steps: applying electrically conductive traces to a first electrically insulative flexible film, positioning openings in a second electrically insulative flexible film, affixing the second electrically insulative flexible film to the electrically conductive traces and the first electrically insulative flexible film such that the openings are positioned over the electrically conductive traces, applying electrodes to the second electrical insulative flexible film such that the electrodes make contact to the electrically conductive traces through the openings in the second electrically insulative flexible film, wrapping the first electrically insulative flexible film, the electrically conductive traces, the second electrically insulative flexible film, and the electrodes to define a tubular shape extending along a longitudinal axis, and affix a sharp end near a first end of the tubular shape. 
     In some embodiments, the method can further include affixing an inner surface of the tubular shape to a needle such that the needle includes the sharp end affixed near the first end of the tubular shape. 
     In some embodiments, the method can further include electrically isolating each of the one or more electrodes from the needle. 
     In some embodiments, the method can further include positioning a thermocouple junction over an outer surface of the needle and electrically isolating the thermocouple junction from the needle. 
     In some embodiments, the method can further include forming a pointed tip at the first end of the tubular shape such that the sharp end includes the pointed tip. 
     In some embodiments, the method can further include forming a pointed tip at the first end of the tubular shape such that the sharp end comprises the pointed tip and forming the tubular shape to comprise columnar rigidity sufficient to lance intravascular tissue. 
     In some embodiments, the method can further include affixing a metal sheet under the first electrically insulative flexible film, wrapping the metal sheet to define an inner surface of the tubular shape, and forming a pointed tip on the metal sheet approximate the first end of the tubular shape such that the sharp end comprises the pointed tip. 
     In some embodiments, the method can further include applying a liner electrode comprising gold to the second insulative flexible film and wrapping the linear electrode to form a band encircling the tubular shape. 
     In some embodiments, the method can further include connecting solder pads, electrically, each to a respective electrically conductive trace of the electrically conductive traces and positioning the openings in the second electrically insulative flexible film such that the electrodes are each electrically connected to a respective trace of the electrically conductive traces. 
     In some embodiments, the method can further include surrounding the tubular shape and the sharp end with a sheath such that the tubular shape and sharp end are slidable to extend the sharp end out of the sheath. 
     In some embodiments, the method can further include electrically isolating the sharp end from the electrodes. 
     In some embodiments, the method can further include electrically isolating each electrode from the remainder of the electrodes. 
     In some embodiments, the method can further include positioning a thermocouple junction at an opening in the second electrically insulative flexible film such that the thermocouple junction comprises a portion of one of the electrodes in contact with one of the electrically conductive traces at the opening. 
     In some embodiments, the method can further include forming the electrode of the thermocouple junction to comprise gold and forming the electrically conductive trace of the thermocouple junction to comprise constantan. 
     In some embodiments, the method can further include positioning a second thermocouple junction between the first electrically insulative flexible film and the second electrically insulative film such that the second thermocouple junction comprises overlapping portions of two electrically conductive traces of the electrically conductive traces. 
     In some embodiments, the method can further include applying a pure gold electrode having a thickness of approximately 0.001 inches (about 25 micrometers) to the second electrically insulative film. 
     In some embodiments, the method can further include positioning thermocouple junctions to be heated by all of the electrodes. 
     In some embodiments, the method can further include positioning a navigation sensor to detect a movement of one or more of the electrodes. 
     In some embodiments, the method can further include positioning a navigation sensor to detect movement of two or more of the electrodes. 
     In some embodiments, the method can further include affixing the navigation sensor approximal a distal end of a catheter and positioning a needle assembly comprising the tubular shape and the sharp end through the catheter such that the needle assembly is confined to move in only one dimension in relation to the navigation sensor. 
     In some embodiments, the method can further include electrically isolating each of the electrodes from the remainder of the electrodes. 
     In some embodiments, the method can further include configuring the electrodes to measure a voltage and/or impedance. 
     In some embodiments, the method can further include wrapping the electrodes to circumscribe the tubular shape. 
     In some embodiments, the method can further include spacing each of the electrodes a predetermined distance from the sharp end and electrically isolating each electrode from the remainder of the electrodes. 
     In some embodiments, the method can further include positioning the electrodes being confined to a distance of approximately 9 mm as measured from a tip of the sharp end. 
     In some embodiments, the step of applying electrodes to the second electrical insulative flexible film can further include applying about 6 to about 10 linear electrodes. The method can further include wrapping each of the linear electrodes to form about 6 to about 10 ring electrodes. 
     In some embodiments, the method can further include spacing each of the ring electrodes with an edge-to-edge spacing to each neighboring ring electrode with a spacing of about 2 mm to about 4 mm. 
     There is further provided, in accordance with some embodiments of the present disclosure, a method for configuring a system for intravascular treatment, the method can include one or more of the following steps: selecting a flexible circuit, wrapping the flexible circuit to form a tubular shape, positioning a navigation sensor, and configuring a processing device. The flexible circuit is selected to have an electrically insulative substrate film, electrically conductive traces disposed over the substrate film, an electrically insulative isolating film disposed over the electrically conductive traces, the electrically insulative film comprising vias therethrough, and electrodes disposed over the isolating film and connected to at least a portion of the conductive traces through the vias. The flexible circuit is wrapped such that the electrodes are shaped as ring electrodes circumnavigating an outer surface of the tubular shape. The sharp end is affixed near a first end of the tubular shape. The navigation sensor is positioned to detect movement, in relation to the navigation sensor, of one or more of the ring electrodes. The processing device is configured to extract electrical measurements from the electrodes and determine, using the navigation sensor, a position of each of the electrodes in relation to intracardial tissue. 
     In some embodiments, the method further includes further configuring the processing device to determine impedance of the intracardial tissue at multiple depths of the tissue in response to lancing the intracardial tissue with the sharp end and inserting the ring electrodes into the intracardial tissue. 
     In some embodiments, the method further includes selecting a catheter, electrically connecting conductive wires each to a respective electrically conductive trace of the electrically conductive traces, extending the conductive wires through the catheter, and electrically connecting a radio frequency generator to at least one of the conductive wires. 
     In some embodiments, the method further includes connecting an electrical measurement tool electrically to a first portion of the electrodes and connecting the radio frequency generator electrically to a second portion of the plurality of electrodes. 
     In some embodiments the electrical measurement tool includes one or more of a voltmeter, an ohmmeter, and an ammeter. 
     There is further provided, in accordance with some embodiments of the present disclosure, a method for configuring a system for intravascular treatment, the method can include one or more of the following steps: selecting a flexible circuit, wrapping the flexible circuit to form a tubular shape, affixing a sharp end near a first end of the tubular shape, selecting a catheter, electrically connecting conductive wires each to a respective electrically conductive trace on the flexible circuit, and electrically connecting a radio frequency generator to at least one of the conductive wires. The flexible circuit is selected to have an electrically insulative substrate film, electrically conductive traces disposed over the substrate film, an electrically insulative isolating film disposed over the electrically conductive traces, the electrically insulative film comprising vias therethrough, and electrodes disposed over the isolating film and connected to at least a portion of the conductive traces through the vias. 
     There is further provided, in accordance with some embodiments of the present disclosure, a method of constructing an ablation tool, the method can include one or more of the following steps: forming an ablation electrode, forming a sharp end affixed to the ablation electrode, and electrically isolating the ablation electrode from the sharp end. 
     There is further provided, in accordance with some embodiments of the present disclosure, a method of constructing an ablation tool, the method can include one or more of the following steps: forming an ablation electrode and forming a thermocouple junction such that the thermocouple junction comprises a portion of the ablation electrode. 
     There is further provided, in accordance with some embodiments of the present disclosure, a method of constructing an ablation tool, the method can include one or more of the following steps: selecting a catheter, affixing a navigation sensor near a distal end of the catheter, positioning a needle assembly having an electrode thereon and a sharp end within the catheter such that the needle assembly is translatable in one dimension in relation to the navigation sensor, the needle assembly is translatable to move the sharp end out of the catheter through the distal end of the catheter, and configuring the navigation sensor to detect movement of the electrode in relation to the navigation sensor. 
     The present disclosure will be more fully understood from the following detailed description of embodiments thereof, taken together with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an illustration of an ablation tool in accordance with some embodiments of the present disclosure; 
         FIG. 2A  is an illustration of a flexible circuit of the ablation tool of  FIG. 1  in a flat configuration in accordance with some embodiments of the present disclosure; 
         FIG. 2B  is an illustration of the flexible circuit of the ablation tool of  FIG. 1  in a tubular shape in accordance with some embodiments of the present disclosure; 
         FIG. 3  is an illustration of an ablation tool in accordance with some embodiments of the present disclosure; 
         FIG. 4A  is an illustration of a flexible circuit of the ablation tool of  FIG. 3  in a flat configuration in accordance with some embodiments of the present disclosure; 
         FIG. 4B  is an illustration of the flexible circuit of the ablation tool of  FIG. 3  in a tubular shape in accordance with some embodiments of the present disclosure; 
         FIG. 5  is an illustration of a flexible circuit in a tubular shape including a pointed end in accordance with some embodiments of the present disclosure; 
         FIG. 6  is an illustration of a flexible circuit having a metal sheet affixed thereto, the flexible circuit and the metal sheet in a tubular shape and including a pointed end in accordance with some embodiments of the present disclosure; 
         FIG. 7  is an illustration of the flexible circuit of  FIG. 5  or  FIG. 6  in a flat configuration in accordance with some embodiments of the present disclosure; 
         FIG. 8A  is an illustration of the metal sheet of  FIG. 6  in a flat configuration in accordance with some embodiments of the present disclosure; 
         FIG. 8B  is an illustration of the metal sheet of  FIG. 6  in a tubular shape in accordance with some embodiments of the present disclosure; 
         FIG. 9  is an illustration of a diagnostic electrode tool in accordance with some embodiments of the present disclosure; 
         FIG. 10A  is an illustration of a flexible circuit of the diagnostic electrode tool of  FIG. 9  in a flat configuration in accordance with some embodiments of the present disclosure; 
         FIG. 10B  is an illustration of the flexible circuit of the diagnostic electrode tool of  FIG. 9  in a tubular shape in accordance with some embodiments of the present disclosure; 
         FIG. 11  is an illustration of layers of a flexible circuit usable for an ablation and/or diagnostic tool in accordance with some embodiments of the present disclosure; 
         FIG. 12  is an illustration of a flexible circuit including a thermocouple that includes a portion of an electrode in accordance with some embodiments of the present disclosure; 
         FIG. 13  is an illustration of a flexible circuit including a thermocouple that is electrically isolated from electrodes; 
         FIG. 14  is an illustration of a sharp end usable for an ablation and/or diagnostic tool in accordance with some embodiments of the present disclosure; 
         FIG. 15  is an illustration of a domed end of an ablation tool as is known; 
         FIG. 16  is an illustration of a needle electrode assembly in accordance with some embodiments of the present disclosure; 
         FIG. 17  is an illustration of an ablation or diagnostic tool in accordance with some embodiments of the present disclosure; and 
         FIG. 18  is a flow diagram for a method of treatment using an ablation or diagnostic tool in accordance with embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     As used herein, the terms “about” or “approximately” for any numerical values or ranges indicate a suitable dimensional tolerance that allows the part or collection of components to function for its intended purpose as described herein. More specifically, “about” or “approximately” may refer to the range of values ±20% of the recited value, e.g. “about 90%” may refer to the range of values from 71% to 99%. 
     As used herein, the terms “tubular” and “tube” are to be construed broadly and are not limited to a structure that is a right cylinder or strictly circumferential in cross-section or of a uniform cross-section throughout its length. For example, the tubular structure or system is generally illustrated as a substantially right cylindrical structure. However, the tubular system may have a tapered or curved outer surface without departing from the scope of the present disclosure. 
     The term “computing system” is intended to include standalone machines or devices and/or a combination of machines, components, modules, systems, servers, processors, memory, detectors, user interfaces, computing device interfaces, network interfaces, hardware elements, software elements, firmware elements, and other computer-related units. By way of example, but not limitation, a computing system can include one or more of a general-purpose computer, a special-purpose computer, a processor, a portable electronic device, a portable electronic medical instrument, a stationary or semi-stationary electronic medical instrument, or other electronic data processing apparatus. 
     The terms “component,” “module,” “system,” “server,” “processor,” “memory,” and the like are intended to include one or more computer-related units, such as but not limited to hardware, firmware, a combination of hardware and software, software, or software in execution. For example, a component may be, but is not limited to being, a process running on a processor, an object, an executable, a thread of execution, a program, and/or a computer. By way of illustration, both an application running on a computing device and the computing device can be a component. One or more components can reside within a process and/or thread of execution and a component may be localized on one computer and/or distributed between two or more computers. In addition, these components can execute from various computer readable media having various data structures stored thereon. The components may communicate by way of local and/or remote processes such as in accordance with a signal having one or more data packets, such as data from one component interacting with another component in a local system, distributed system, and/or across a network such as the Internet with other systems by way of the signal. Computer readable medium can be non-transitory. Non-transitory computer-readable media include, but are not limited to, random access memory (RAM), read-only memory (ROM), electronically erasable programmable ROM (EEPROM), flash memory or other memory technology, compact disc ROM (CD-ROM), digital versatile disks (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other tangible, physical medium which can be used to store computer readable instructions and/or data. 
       FIG. 1  is an illustration of an ablation tool including needle assembly  100   a  retractable into a catheter  200  or otherwise sheathed. The needle assembly  100   a  can include a sharp end  110   a  and a flexible circuit  120   a.  The needle assembly  100   a  can include a hollow needle  102   a  having a pointed tip  104   a  and a hollow lumen  106 . During an ablation treatment, conductive fluid can be delivered through the lumen  106 . Lesion size can be increased by increasing thermal conductivity of tissue by delivering fluid through the needle assembly  100   a  in a manner similar to as disclosed in U.S. Pat. No. 9,326,813 which is hereby incorporated by reference in its entirety into this application as if set forth in full and attached in the appendix to priority application U.S. 62/943,552. During treatment, the distal, pointed end  104   a  of the hollow needle  102   a  can be introduced into tissue, electrically-conductive fluid can be infused through the needle and into the tissue, and the tissue can be ablated after and/or during introduction of the fluid into the tissue. The fluid conducts ablation energy within the tissue to create a larger lesion than would be created without introduction of the fluid. During ablation, electrical current can be supplied to the tissue via one or more electrodes  136   a  on the flexible circuit  120   a.  The flexible circuit  120   a  can include an electrically insulative flexible substrate. The flexible circuit  120   a  can be wrapped around the needle  102   a  to define a tubular shape. Once affixed to the needle  102   a,  the flexible circuit  120   a  is no longer flexible, meaning the circuit  120   a  is fixed in relation to the needle  102   a.  The electrode(s)  136   a  can be electrically isolated from the needle  102   a  at least by virtue of the insulative properties of the flexible substrate in addition to any intermediate insulative layers of the flexible circuit  120   a.    
     The needle assembly  100   a  can be slidably translatable in relation to the catheter or sheath  200  (referred to herein for simplicity as “catheter”). The catheter  200  is further illustrated in  FIG. 17 . Referring collectively to  FIGS. 1 and 17 , the needle assembly  100   a  can be slidably retracted into the opening  204  of the catheter  200  when the needle assembly  100   a  is manipulated before and after treatment. The needle assembly  100   a  can be sheathed to reduce the risk of inadvertently puncturing tissue. A navigation sensor  70  can be positioned in the catheter  200  near the distal end of the catheter  200 . The navigation sensor  70  can be positioned and otherwise configured to detect movement of the needle assembly  100   a  in relation to the catheter  200 . The navigation sensor can be configured to detect whether the needle assembly  100   a  is fully sheathed within the catheter  200 . The sensor  70  can be in a fixed location in the catheter tip. In some applications the sensor  70  can be configured to provide signals to an electrode mapping system, and the electrode mapping system can determine a relative location of the needle assembly  100   a  based on the signals from the sensor  70 . The electrode mapping system can thereby provide data indicating the status of the needle assembly  100   a  as being sheath/un-sheathed as well as data indicative of an intra-dermal signal location. Configured as such, the electrode mapping system can provide a z component of the position of the needle assembly  100   a  in addition to an x and y position. 
       FIG. 2A  is an illustration of the flexible circuit  120   a  of the ablation tool of  FIG. 1  in a flat configuration.  FIG. 2B  is an illustration of the flexible circuit  120   a  of the ablation tool of  FIG. 1  in a tubular shape. 
     Referring collectively to  FIGS. 1, 2A, and 2B , the flexible circuit  120   a  can include a rectangular flex circuit with a surface  130  at least partially covered by a sputtered gold electrode surface  136   a.  The rectangular flex circuit  120   a  can be attached by wrapping around the hollow needle  102   a  using adhesive and/or thermal processing. The flex circuit  120   a  can be electrically isolated from the needle  102   a.  The flex circuit  120   a  can further be electrically isolated from all other conductive surfaces of the ablation tool. The needle assembly  100   a  can include isolated trace(s) leading from the ablation electrode zone  136   a  to a solder pad  122  near the proximal edge  132  of the flex circuit  120   a.  One or more lead wires can be attached for connection back through the catheter  200  such that the lead wires ultimately connect to an RF generator. The needle  102   a  can be electrically isolated from the RF circuit. When the needle  102   a  is electrically isolated from ablation energy from the RF generator, the tip  104   a  of the needle  102   a  can have a sharp point (see also  FIG. 14 ). When the needle  102   a  is not electrically isolated from ablation energy from the RF generator, the tip  104   a  of the needle  102   a  can have a rounded edge so as to mitigate non-uniform current distribution and heating during ablation (see also  FIG. 15 ). A sharper needle generally requires less force to puncture the heart tissue. Advantages of isolating the needle tip  104   a  from the electrode  136   a  can therefore include the ability to have a sharper needle tip  104   a  to more easily puncture tissue and an electrode geometry shaped to further mitigate effects of non-uniform current distribution and heating during ablation. 
     During ablation, RF energy can be delivered from a generator to the solder pad  132 , from the solder pad  132  to the flex circuit electrode  136   a,  from the flex circuit electrode  136   a  to tissue adjacent the electrode  136   a,  and back through system return electrode (not shown). The system return electrode can be configured in a similar manner as predicate devices. In some applications, RF energy can be delivered from the ablation zone  136   a  such that leakage to adjacent catheter structures such as dome and needle is minimized. The tool need not include irregular structures on the electrode surface  136   a,  therefore current density across ablation surface  136   a  can be substantially uniform. 
     Referring to  FIG. 2A , the flexible circuit can be manufactured to a rectangular shape. The flexible circuit  120   a  can have a substantially uniform thickness across the area of the electrode  136   a.  The rectangular shape can be wrapped to define a tubular shape as illustrated in  FIG. 2B  and  FIG. 1 . In the tubular shape, the flexible circuit  120   a  can maintain a substantially uniform thickness in the area of the electrode  136   a.  The rectangular shape can be wrapped such that longitudinal sides  126 ,  128  of the circuit abut to create a smooth transition between the edges  126 ,  128  in the electrode region  136   a  when in the tubular shape. Configured as such, the electrode  136   a  can be substantially radially symmetrical about a longitudinal axis  10 . Radial electrode symmetry can provide a more predictable and repeatable lesion compared to needle assemblies using the needle as an electrode. Radial electrode symmetry can provide a lesion that is less affected by the orientation of the needle assembly  100   a  with respect to the target tissue surface (e.g. an angled lance vs. a perpendicular lance) compared to needle assemblies using the needle as an electrode. 
     Risk of current leakage from the electrode  136   a,  through tissue or fluid, to the sharp end  110   a  or another needle surface can be mitigated by physically offsetting the ablation zone  136   a  from the sharp end  110   a  and the needle surface. The ablation zone  136   a  can be physically offset by positioning a distal edge of the ablation zone a predetermined distance from the distal end  124  of the flexible circuit  120   a.  The needle assembly  100   a  can thereby be configured to deliver essentially all of the ablation energy to targeted tissue. 
     Referring collectively to  FIGS. 1, 2A, and 2B , the flexible circuit  120   a  can have an outer surface  130  that includes the electrode surface  136   a  and an insulated surface  134  positioned in a proximal direction in relation to the electrode surface  136   a.  The insulated surface  134  can electrically isolate the needle assembly  100   a  from the catheter  200  during ablation. The insulated surface  130  can further cover one or more electrical traces connecting the electrode  136   a  to the solder pad  132 . 
       FIG. 3  is an illustration of an ablation tool including a needle assembly  100   b  having multiple electrodes  136   b - f  and solder pads  132 . The electrodes  136   b - f  can be electrically isolated from each other. The electrodes  136   b - f  can each be electrically isolated from the sharp end  110   a.  The multiple solder pads  132  can each respectively electrically connect to some or all of the electrodes  136   b - f.  The electrodes  136   b - f  can be connected to solder pads  132  in a one-to-one fashion. Alternatively, an electrode  136   b - f  can connect to multiple solder pads  132 , a solder pad  132  can connect to multiple electrodes  136   b - f,  and/or an electrode  136   b - f  can be floating, lacking a solder pad connection. RF ablation energy can be applied separately at each electrode  136   b - f  to provide differing ablation energy at different tissue depths. Additionally, or alternatively, one or more electrodes  136   b - f  can be connected to an electrical measurement tool. 
       FIG. 4A  is an illustration of the flexible circuit  100   b  of the ablation tool of  FIG. 3  in a flat configuration. In the flat configuration, the electrodes  136   b - f  can be substantially linear, spanning between the longitudinal edges  126 ,  128 . The solder pads  132  can be substantially linear, spanning between the longitudinal edges  126 ,  128 . 
       FIG. 4B  is an illustration of the flex circuit  120   b  of the ablation tool of  FIG. 3  in a tubular shape. The linear electrodes  136   b - f  in the flat configuration can become ring electrodes  136   b - 136   f  when the flex circuit  120   b  is wrapped to the tubular shape. 
     The ablation system, needle assembly  100   b,  and component parts thereof illustrated in  FIGS. 3, 4A, and 4B  can otherwise be constructed, include functionality, and include features as described in relation to the ablation system, needle assembly  100   a,  and component parts thereof as illustrated and described in relation to  FIGS. 1, 2A, and 2B . 
       FIG. 5  is an illustration of a needle assembly  100   c  including a circuit  120   c  in a tubular shape including a pointed end  110   b.  The circuit  120   c  can be a flexible circuit board that is wrapped to the tubular shape illustrated. Once in the tubular shape, the circuit  120   c  can have sufficient structural stability and columnar rigidity to perforate tissue during ablation without substantially deforming. In some embodiments, the needle assembly  100   c  need not include structural support within the lumen  176  of the tubular circuit  120   c.  The surface of the lumen  176  can correspond to a bottom surface  174  of an electrically insulative substrate film of the flexible circuit board  120   c  (see also  FIG. 11 ). The lumen  176  of the circuit  120   c  can further be sized and otherwise configured to provide a fluidic path for conductive fluid to aid in ablation. The lateral sides  126 ,  128  of the tubular circuit  120   c  can be fused together or otherwise jointed to create a fluid impermeable seam. 
     The ablation system, needle assembly  100   c,  and component parts thereof illustrated in  FIG. 5  can otherwise be constructed, include functionality, and include features as described in relation to the ablation system, needle assembly  100   a,  and component parts thereof as illustrated and described in relation to  FIGS. 1, 2A, and 2B . Further, the needle assembly  100   c  illustrated in  FIG. 5  can include multiple electrodes in the electrode region  130  such as illustrated and described in relation to  FIGS. 3, 4A, and 4B . 
       FIG. 6  is an illustration of a needle assembly  100   d  including a circuit  120   c  having a metal sheet  140  affixed thereto. The circuit  120   c  and the metal sheet  140  are illustrated in a tubular shape including a pointed end  110   c.  The metal sheet  140  can provide additional columnar rigidity to support the tubular circuit  120   c.  The circuit  120   c  therefore can, but need not, have sufficient columnar rigidity to lance tissue without significant deformation absent the metal sheet  140 . The circuit  120   c  illustrated in  FIG. 6  can otherwise be constructed, include functionality, and include features as described in relation to the circuit  120   c  illustrated in  FIG. 5 . 
       FIG. 7  is an illustration of the circuit  120   c  of  FIG. 5  or  FIG. 6  in a flat configuration. The circuit  120   c  can have a triangular shape near the distal end  114  of the flat circuit  120   c  such that when the circuit  120   c  is wrapped to form a tube, the triangular shape forms the sharp end  110   b  illustrated in  FIG. 5  or a portion of the sharp end  110   c  illustrated in  FIG. 6 . The outer surface  130  of the circuit  120   c  can be insulative within the triangular shape. 
       FIG. 8A  is an illustration of the metal sheet  140  of  FIG. 6  in a flat configuration. The metal sheet can have lateral edges  126 ,  128  that can overlap when the metal sheet  140  is formed in the tubular shape. 
       FIG. 8B  is an illustration of the metal sheet  140  of  FIG. 6  in a tubular shape. The metal sheet  140  can be affixed to the flexible circuit board  120   c  in either the flat or the tubular shape. The metal sheet  140  can include perforations to reduce weight of the metal sheet  140 . 
       FIG. 9  is an illustration of a diagnostic electrode tool including a diagnostic needle assembly  100   e  having multiple electrodes  136   g - p.  The needle assembly  100   e  can include a flexible circuit  120   d.    
       FIG. 10A  is an illustration of the flex circuit  120   d  of the ablation tool of  FIG. 9  in a flat configuration. In the flat configuration, the electrodes  136   g - p  can be substantially linear, spanning between the longitudinal edges  126 ,  128  of the circuit board  120   d.  The solder pads  132  can be substantially linear, spanning between the longitudinal edges  126 ,  128  of the circuit board  120   d.  In other words, when flat, the flexible circuit  120   d  can be rectangular with part of the outer surface  130  covered in rectangular bands of sputtered gold  136   g - p.    
       FIG. 10B  is an illustration of the flex circuit  120   d  of the ablation tool of  FIG. 9  in a tubular shape. The linear electrodes  136   g - p  in the flat configuration can become ring electrodes  136   g - p  when the flex circuit  120   d  is wrapped to the tubular shape. In other words, when tubular, the rectangular bands of sputtered gold  136   g - p  can form rings circumscribing the tubular shape. 
     Referring collectively to  FIGS. 9, 10A, and 10B , the needle assembly  100   e  can further include a needle  102   b.  The flexible circuit  120   d  can be wrapped around the needle  102   b.  The flexible circuit  120   d  can be affixed to the needle  102   b  using adhesive, thermal processing, or other means as would be appreciated and understood by a person of ordinary skill in the art. Once formed, the bands  136   g - p  can form a series of spaced and isolated ring electrodes wrapped laterally around the needle frame (wrapped circumferentially about a longitudinal axis  10 ). Each electrode  136   g - p  can be electrically isolated and linked by a trace on the circuit board  120   d  to a solder pad  132 . Lead wires can be attached to the solder pads  132  to link to a diagnostic system. 
     The ring electrodes  136   g - p  can be configured to detect bipolar electrocardiograph (ECG) signals, uni-polar ECG signals, impedance, activation voltage, and other electrically detectable signals as would be appreciated and understood by a person of ordinary skill in the art. The array of ring electrodes  136   g - p  can further be configured to observe myocardium electrical properties at depth. For instance, catheter  200  of the diagnostic electrode tool can include a navigation sensor paired with CARTO mapping and diagnostic software (or similar software as would be appreciated and understood by a person of ordinary skill in the art). 
     In some embodiments, the diagnostic electrode tool can be configured to serve as a lesion assessment tool. The needle assembly  100   e  can be moved to penetrate a known lesion location or suspected leak area in a lesion. Once at least some of the electrodes  136   g - p  are positioned within the tissue, a physician or other user can utilize the electrodes to determine relative tissue impedance at depth. The relative tissue impedance can be used to determine lesion depth, lesion quality, and/or sub lesion signal propagation. Such data can direct additional focused analysis (e.g. RF analysis). Using such a lesion assessment tool, can, in some applications, provide a physician with a means for directly verifying lesion quality or trouble shooting electrically leaking lesions as an alternative to clinical design validation models or indirect measurement with surface diagnostics. 
     In some embodiments, the diagnostic electrode tool can be configured to serve as a subsurface diagnostic tool. The needle assembly  100   e  can be moved to penetrate myocardial tissue in multiple locations. At each location, a physician or other user can utilize the electrodes to obtain electrical measurements of the myocardial tissue at multiple depths. The multiple depth readings of myocardial tissue can be overlaid against a marker signal to collate individual observation points. A computing system provided with the multiple depth readings and marker signal can be configured to piece together one or more 3-D models of electrical signal propagation, electrical signal activation, and/or impedance. Triangular boundary conditions can be utilized to identify potential activation points for ablation that are not apparent when performing a similar analysis using surface contact diagnostic devices lacking depth readings. 
     In some embodiments, the diagnostic electrode tool can serve as an alternative to using a needle ablation catheter as a diagnostic tool. The diagnostic electrode tool having multiple electrodes  136   g - p  can provide greater granularity in electrical signal modeling compared to a needle ablation catheter having a single ablation electrode. The multiple electrodes  136   g - p  can essentially act as an antenna array as opposed to one larger antenna in a single electrode tool. 
     Electrode spacing, electrode surface area, and electrode quantity can be configured according to the needs of a given diagnostic application (e.g. create a clinically useful signal profile). In some embodiments, the circuit board  120   d  can include about 5 bipolar pairs (about 10 electrodes total). Alternatively, the circuit board  120   d  can include about 6 electrodes. In some embodiments, electrodes can be evenly spaced with uniform edge-to-edge spacing. Alternatively, electrodes can have a non-uniform edge-to-edge spacing arrangement (e.g. 2 mm-4 mm-2 mm-4 mm-2 mm . . . ) In some embodiments, each of the electrodes can be spaced over a about a 9 mm penetration depth as measured from the tip  104   b  of the needle  102   b  along the longitudinal axis  10 . 
       FIG. 11  is an illustration of layers of a flexible circuit  120  usable for an ablation and/or diagnostic tool. The flexible circuits  120   a - f  otherwise illustrated and described herein can be constructed similar to as illustrated in  FIG. 11  and described in relation to  FIG. 11 . The flexible circuit  120  can have a substrate layer  172 , an adhesive layer  170 , a trace array layer  160 , an intermediate electrically insulative layer  150 , electrodes  136   q - r,  and solder pads  132 . The flexible circuit  120  can have a bottom surface  174  that includes the bottom side of the substrate layer  172 . The flexible circuit  120  can have a top surface  130  that includes top surfaces of the electrodes  136   q - r,  portions of a top surface of the intermediate electrically insulative layer  150 , and top surfaces of the solder pads  132 . 
     The electrodes  136   q - r  can include gold. The electrodes  136   q - r  can be pure gold. Electrodes can have a thickness of about  1  micrometer to about 2 micrometers. The electrodes can have an edge-to-edge spacing D. The edge-to-edge spacing D between electrodes can be uniform. Alternatively, the edge-to-edge spacing D can be variable between one pair of electrodes to the next pair of electrodes. Minimum edge-to-edge spacing D between electrodes can be determined by application specific factors such as potential electrical interference between electrodes and limitations of fabrication. Maintaining electrical isolation between adjacent electrodes can be a determining factor for minimum edge-to-edge spacing. In some applications, an edge-to-edge spacing of about 0.05 mm can be achievable with present fabrication techniques and can be sufficient to maintain electrical isolation. In some applications, achieving minimum edge-to-edge spacing may not be an objective. 
     For the purposes of ablation and/or sensing as described herein, it can be advantageous to use the following spacings. The circuit board  120  can include an edge-to-edge spacing D arrangement of 2 mm-4 mm-2 mm-4 mm-2 mm. The circuit board  120  can include between about 10 electrodes and about 6 electrodes. The electrodes  136   q - r  can be spaced over a length of between about 7 millimeters to about 9 millimeters from the distal end  124  of the flexible circuit  120 . The electrodes  136   s - r  can have a rectangular shape, extending linearly across a width of the flexible circuit  120 . A flexible circuit  120  having linear (rectangular) electrodes  136   s - r  can be wrapped to form ring electrodes  136   s - r.    
     The intermediate electrically insulative layer  150  can include a polymer such as a flexible polyimide. The intermediate electrically insulative layer  150  can include a Felios RF 775 Polyimide Flex with copper removed. The intermediate electrically insulative layer  150  can have a thickness of about 25 micrometers. Alternatively, the intermediate electrically insulative layer  150  can have a thickness and/or material structure sufficient to achieve structural and electrical functionality as described here. For instance, the intermediate electrically insulative layer can include an electrically insulating flexible sheet having a thickness of about 12.5 micrometers or 50 micrometers as presently commercially available. The intermediate electrically insulative layer  150  can include openings  152   a - c  to provide connection between the electrodes  136   q - r  to traces on the trace array layer  160  and solder pads  132  to traces on the trace array layer  160 . The openings  152   a - c  can be filled with a conductive material. The openings  152   a - c  can function as vias. 
     The trace array layer  160  can include electrically conductive traces  162   a - d,    166   a - b  (see also  FIGS. 12 and 13 ). The traces  162   a - d,    166   a - b  can have a thickness of about 1 micrometer to about 2 micrometers. 
     The adhesive layer  170  can have a thickness of about 25 micrometers or less, preferably with a minimum thickness sufficient maintain sufficient adhesion. A thickness of between about 12 micrometers and about 13 micrometers is preferred. In needle assembly embodiments lacking an inner tube (e.g. needle or metallic sheet) for structural support, the adhesive layer  170  can be made thicker as the lack of needle wall thickness allows more space for other layers without affecting the overall size of the needle assembly. The adhesive layer  170  can include an acrylic adhesive. The adhesive can be coated on release paper. The adhesive layer  170  can include a Dupont Pyralux LF sheet adhesive such as LF0100 or similar product. 
     The substrate layer  172  can have a thickness of between about 12 micrometers and about 13 micrometers. Alternatively, the intermediate electrically insulative layer  150  can have a thickness and/or material structure sufficient to achieve structural and electrical functionality as described here. For instance, the intermediate electrically insulative layer can include an electrically insulating flexible sheet having a thickness of about 12.5 micrometers or 50 micrometers as presently commercially available. The substrate layer  172  can include an acrylic adhesive. The substrate layer can include a polyamide film. The substrate layer  172  can be a composite of an acrylic, polyamide film, and/or other insulative flexible materials. The substrate layer  172  can include a Dupont Pyralus LF coverlay such as LF7001. 
       FIG. 12  is an illustration of a flexible circuit  120   e  including a thermocouple  168   a  that includes a portion of an electrode  136   t  and a trace  166   a  on the patterned layer  160 . The trace  166   a  can include constantan. The trace  166   a  can make contact to the electrode  136   t  through a via  152   g.  Configured as such, the thermocouple junction  168   a  can be separated from an ablation surface of tissue by the sum of the electrode  136   t  thickness and intermediate insulative layer  150  thickness (e.g. about 26 micrometers). The thermocouple  168   a  can thereby be in direct contact with the electrode  136   t.    
     The trace array later  160  can further include traces  162   a - c  of the same material as electrodes  136   s - v.  The electrode traces  162   a - c  can each be in contact with a respective electrode  136   s - v  through a respective via  152   d - f.  Some or all of the electrode traces  162   a - c  can each provide a path for ablation current to the respective electrode  136   s - u.  Additionally, or alternatively, some or all of the electrode traces  162   a - c  can provide a path for electrical signal measurement from the respective electrode  136   s - u.    
     Each of the traces  162   a - c,    166   a  can connect to a respective solder pad  132 . 
       FIG. 13  is an illustration of a flexible circuit  120   f  including a thermocouple  168   b  that is electrically isolated from the electrodes  136   w - z.  The thermocouple  168   b  can be confined to the trace array layer  160 . The thermocouple  168   b  can include a constantan trace  166   b  and a gold trace  164 . The trace array layer  160  can further include electrode traces  162   d - e  in contact with electrodes  136   x - y  through vias  152   h - i.  Each of the traces  162   d - e,    164 ,  166   b  can connect to a respective solder pad  132 . Some or all of the electrode traces  162   d - e  can each provide a path for ablation current to the respective electrode  136   x - y.  Additionally, or alternatively, some or all of the electrode traces  162   d - e  can provide a path for electrical signal measurement from the respective electrode  136   x - y.    
     Referring collectively to  FIGS. 11 and 12 , a needle assembly  100 ,  100   a - e  including a flexible circuit  120   e - f  having a thermocouple  168   a - b  integrated therein can be configured to perform temperature controlled ablations through automated temperature feedback from thermocouples  168   a - b.    
     Any of the flexible circuits  120 ,  120   a - f  illustrated herein can include electrodes configured to extract electrical signals for diagnostic purposes in addition to electrodes configured to provide electrical current for ablation. In some embodiments, one or more diagnostic electrodes can be positioned in the distal direction and/or in the proximal direction in relation to each ablation electrode. Positioned as such, the diagnostic electrodes can be configured to provide data to a computing device configured to determined, based on the provided data, whether each respective diagnostic electrode is in contact with scar tissue or activating tissue. The computing device can further be configured to control electrical current output from respective ablation electrodes to target activating tissue. As illustrated in  FIGS. 12 and 13 , electrodes  136   t,    136   x  in close proximity to thermocouple junctions  168   a - b  can be configured for ablation while electrodes  136   s,    136   u,    136   w,    136   y  on either side the ablation electrodes  136   t,    136   x  can be configured as diagnostic electrodes. 
     Thermocouples  168   a - b  can be placed in relation to the electrode  136   t,    136   x  surface. Assuming a uniform thickness and shape of an ablative electrode  136   t,    136   x,  a thermocouple  168   a - b  can be placed centered in the ablative surface to represent the temperature across the surface. Additionally, or alternatively, the thermocouple  168   a - b  can be placed near an edge of the electrode  136   t,    136   x  to capture boundary temperatures. Multiple ablation zones can be accommodated by shorting to multiple individual or shared constantan traces. Alternatively, a constantan trace can be electrically insulated from the remainder of the constantan traces. In some applications, a thermocouple  168   a  in electrical contact with an electrode  136   t  can have improved thermal performance compared to an isolated thermocouple  168   b  separated from the ablative electrode  136   x  by the thickness of the intermediate electrically insulative layer  150 . The thermocouple  168   b  isolated from the electrode  136   x  can have mitigated signal noise compared to the thermocouple  168   a  in electrical contact with the electrode  136   t.    
     The thermocouples  168   a - b  can have greater thermal conductivity to ablative electrodes  136   t,    136   x  compared to thermal conductivity to fluidic flow through the needle assembly lumen  106 ,  146 ,  176 . 
       FIG. 14  is an illustration of a sharp end  104   a  of a needle  102   a  usable for an ablation and/or diagnostic tool according to the teachings of the present disclosure. The end  104   a  can have a blade edge. Because the end  104   a  can be electrically isolated from electrodes  136   a - z,  the abruptness of the structure need not result in current crowding. Similarly, a needle  102   b  of a diagnostic tool can include a pointed tip  104   b  according to the teachings of the present disclosure. 
       FIG. 15  is an illustration of a rounded end  104   c  of a needle  102   c  usable for an ablation and/or diagnostic tool where the needle  102   c  serves as an ablation electrode as known in the art. The end  104   c  is rounded to mitigate effects of current crowding and hot spots during ablation. 
       FIG. 16  is a cross-sectional illustration of a needle electrode assembly  46  including a needle assembly  100 , an outer tube  48 , proximal tubing  33 , joining tubing  45 , a spacer  51 , and wiring  138 . Any of the needle assemblies  100   a - e  illustrated and otherwise described herein can be affixed as part of a needle electrode assembly such as the needle assembly  100  is illustrated in relation to the needle electrode assembly  46  in  FIG. 16 . 
     The needle electrode assembly  46  can be aligned along a longitudinal axis  10 . The spacer  51  can inhibit bodily fluid from entering the needle electrode assembly  46 . A portion of the flexible circuit  120  can be positioned within the outer tube  48 . The flexible circuit  120  can be otherwise configured as any of the flexible circuits  120   a - f  otherwise described and illustrated herein. The electrode section  136  of the flexible circuit  120  can be affixed external to the outer tube  48  such that the electrodes are positioned to enter tissue upon penetration by the needle assembly  100 . Wires  138  can extend through the outer tube  48  and can be accessible to a physician or other user during a treatment. The wires  138  can be connected to a RF generator, other ablation energy source, voltmeter, ohmmeter, ammeter, and/or other electrical measurement tool. 
       FIG. 17  is an illustration of an ablation or diagnostic tool. The needle electrode assembly  46  including the needle assembly  100  can be slidably positioned within a protective tubing or sheath  47  affixed stationary in relation to the catheter  200 . The needle electrode assembly  46  can be retracted such that the sharp end  110  of the needle assembly  100  is retracted into the sheath  47 . The sharp end  110  can be configured as any of the sharp ends  110   a - d  otherwise described and illustrated herein. The catheter  200  can include an infusion lumen  24  in fluidic communication with the lumen  106 ,  146 ,  176  of the needle assembly  100 ,  100   a - e.    
     The catheter  200  can include a navigation sensor  70 . The navigation sensor  70  can be contained within the catheter  200  near the distal end of the catheter  200 . The navigation sensor  70  can be used to detect movement of an electrode  136   a - z  of the needle assembly  100  in relation to the distal end of the catheter  200 . The navigation sensor  70  can further be used to determine the coordinates of the distal end of the catheter  200 . The navigation sensor  70  can be connected to a sensor cable  72 . The sensor cable  72  can extend through a lumen  28  of the catheter  200  and can be connected to an electrical measurement tool. 
     The catheter  200  can include a tip electrode  32 . The tip electrode  32  can include a passage  56  through which the sheath  47  extends. The tip electrode  32  can be connected to tubing  19  by a plastic housing  34 . The tip electrode  32  can be configured to measure electrical signals at tissue surface. The catheter  200  can further include a ring electrode  38  configured to measure electrophysiology. The tip electrode  32  and ring electrode  38  can each be connected to a separate lead wire  40 . The wires  40  can be connected to electrical measurement tools. 
     By combining the navigation sensor  70  and the electrodes  32 ,  38 , a physician or other user can simultaneously map contours or shape of a heart chamber, electrical activity of the hear, and extent of displacement of the catheter  200 . 
       FIG. 18  is a flow diagram illustrating a method  300  of treatment using an ablation or diagnostic tool. The method  300  can include one or more of the following steps presented in no particular order. The example method  300  can include additional steps as would be appreciated and understood by a person of ordinary skill in the art. The example method can be performed by a physician or other user utilizing an example diagnostic and/or ablation tool including a needle assembly  100 ,  100   a - e  as illustrated and disclosed herein, a variation thereof, or an alternative thereto as would be appreciated and understood by a person of ordinary skill in the art. 
     At step  302 , a sheathed needle assembly can be delivered to a treatment site. The needle assembly can be a needle assembly  100 ,  100   a - e  as illustrated and disclosed herein, a variation thereof, or an alternative thereto as would be appreciated and understood by a person of ordinary skill in the art. The needle assembly can be sheathed within a catheter or other sheath such as catheter  200  as illustrated and disclosed herein, a variation thereof, or an alternative thereto as would be appreciated and understood by a person of ordinary skill in the art. 
     At step  304 , the needle assembly can be unsheathed. The needle assembly can be unsheathed by sliding the needle assembly out of an opening in a distal end of a catheter or other sheath. For instance, the needle assembly  100 ,  100   a - e  can be slid out of opening  204  of catheter  200  as illustrated and disclosed herein, a variation thereof, or an alternative thereto as would be appreciated and understood by a person of ordinary skill in the art. 
     At step  306 , movement of the needle assembly in relation to the sheath can be detected. For instance, the catheter can include a navigation sensor such as the navigation sensor  70  as illustrated and disclosed herein, a variation thereof, or an alternative thereto as would be appreciated and understood by a person of ordinary skill in the art. The navigation sensor can be configured to detect movement of the needle assembly in relation to the navigation sensor. The needle assembly can be configured to move in only one dimension in relation to the navigation sensor. 
     At step  308 , tissue in or around the heart can be lanced with the needle assembly. The needle assembly can include a sharp end shaped to lance tissue such as a sharp end  110 ,  110   a - d  as illustrated and disclosed herein, a variation thereof, or an alternative thereto as would be appreciated and understood by a person of ordinary skill in the art. 
     At step  310 , one or more electrodes isolated from the sharp end of the needle assembly can be moved into the tissue. 
     At step  312 , one or more of the electrodes can be used to ablate and/or sense tissue. 
     The descriptions contained herein are examples of embodiments of the invention and are not intended in any way to limit the scope of the invention. As described herein, the invention contemplates many variations and modifications of ablation tools and diagnostic tools, including alternative numbers of electrodes, alternative combinations of electrodes, combinations of components illustrated in separate figures, alternative materials, alternative component geometries, and alternative component placement. Modifications and variations apparent to those having ordinary skill in the art according to the teachings of this disclosure are intended to be within the scope of the claims which follow.