Devices and kits for the transmission of radiofrequency energy to a guidewire and methods thereof

Abstract

The present disclosure relates, generally, to devices and kits for transmission of radiofrequency (RE) energy to a guidewire. Methods of energizing a guidewire with RE energy using the devices and kits of the invention are also provided.

Description

[0001] ATTORNEY DOCKET NO: 51856-002WO2 PATENT

[0002] DEVICES AND KITS FOR THE TRANSMISSION OF RADIOFREQUENCY ENERGY TO A GUIDEWIRE AND METHODS THEREOF

[0003] BACKGROUND OF THE INVENTION

[0004] The use of radiofrequency (RF) generators and electrodes (e.g., guidewires) applied to tissue for pain relief or functional modification is well known. Typical configurations for transmitting RF energy from an RF generator to a guidewire include the connection of the guidewire on the proximal end to the RF generator. Consequently, the length of the guidewire is fixed, and the guidewire is reliant on a single contact point for RF energy transmission.

[0005] Accordingly, new devices and methods are needed to facilitate the transmission of RF energy to a guidewire for medical procedures.

[0006] SUMMARY OF THE INVENTION

[0007] The present invention relates to devices, kits, and methods for facilitating the transfer of RF energy for, e.g., cardiological, cardiovascular, electrophysiological, endovascular, interventional cardiological, interventional radiological, and other medical procedures, such as tissue and / or blood vessel ablation. Furthermore, the present invention provides a consistent transfer of RF energy while maintaining the ability to safely advance and retract the guidewire with resistance.

[0008] In a first aspect, the invention features a device for transmitting RF energy to a guidewire. The device includes a housing, a tube, and an RF connector operably connected to the tube. The housing includes an inlet and an outlet. The tube is disposed between the inlet and the outlet and includes an inlet segment, an outlet segment, and a middle segment disposed therebetween. The middle segment of the tube includes a plurality of bends relative to the center axis of the inlet segment, outlet segment, or both thereof. The tube and the RF connector transmit RF energy. The guidewire passing from the inlet through the tube and out the outlet contacts the tube to transmit RF energy from the RF connector to the guidewire.

[0009] In some embodiments, the device further includes a first fastener connected to the inlet and a second fastener connected to the outlet. In some embodiments, the first fastener and the second fastener each include a Luer fastener. In some embodiments, the housing encases the tube and the RF connector.

[0010] In some embodiments, the device further includes a switch to allow or cease RF transmission between the RF connector and the tube. In some embodiments, the device further includes timer circuitry to control a time length of RF transmission to the tube. In some embodiments, the timer circuitry further limits the number of consecutive pulses. In some embodiments, the device further includes control circuitry to limit a maximum power of RF transmitted to the tube or a maximum time length of RF transmission to the tube.

[0011] In some embodiments, the inlet segment or the outlet segment does not include a bend. In some embodiments, the plurality of bends includes from 3 to 32 bends (e.g., 3 bends, 4 bends, 5 bends, 6 bends, 7 bends, 8 bends, 9 bends, 10 bends, 11 bends, 12 bends, 13 bends, 14 bends, 15 bends, 16 bends, 17 bends, 18 bends, 19 bends, 20 bends, 21 bends, 22 bends, 23 bends, 24 bends, ATTORNEY DOCKET NO: 51856-002WO2

[0012] PATENT

[0013] 25 bends, 26 bends, 27 bends, 28 bends, 29 bends, 30 bends, 31 bends, or 32 bends). In some embodiments, the plurality of bends includes three bends configured to provide three points of contact between the guidewire and the tube. In some embodiments, the plurality of bends form one or more waves, e.g., wherein the middle segment comprises four waves per inch of the middle segment.

[0014] In some embodiments, the middle segment includes a portion having a degree of curvature from about 2 degrees to about 10 degrees (e.g., about 2 degrees, about 3 degrees, about 4 degrees, about 5 degrees, about 6 degrees, about 7 degrees, about 8 degrees, about 9 degrees, or about 10 degrees). In some embodiments, the middle segment includes a portion having an off-axis deflection of from about 0.005 inch to about 0.020 inch (e.g., about 0.005 inch, about 0.006 inch, about 0.007 inch, about 0.008 inch, about 0.009 inch, about 0.010 inch, about 0.011 inch, about 0.012 inch, about 0.013 inch, about 0.014 inch, about 0.015 inch, about 0.016 inch, about 0.017 inch, about 0.018 inch, about 0.019 inch, or about 0.020 inch) from the center axis of the inlet segment, the outlet segment, or both thereof. In some embodiments, the middle segment includes a portion having an arc length of from about 1 inch to about 5 inches (e.g., about 1 inch, about 1 .1 inches, about 1 .2 inches, about 1 .3 inches, about 1 .4 inches, about 1 .5 inches, about 1 .6 inches, about 1 .7 inches, about 1 .8 inches, about 1 .9 inches, about 2 inches, about 2.1 inches, about 2.2 inches, about 2.3 inches, about 2.38 inches, about 2.4 inches, about 2.5 inches, about 2.6 inches, about 2.7 inches, about 2.8 inches, about 2.9 inches, about 3 inches, about 3.1 inches, about 3.2 inches, about 3.3. inches, about 3.4 inches, about 3.5 inches, about 3.6 inches, about 3.7 inches, about 3.8 inches, about 3.9 inches, about 4 inches, about 4.1 inches, about 4.2 inches, about 4.3 inches, about 4.4 inches, about 4.5 inches, about 4.6 inches, about 4.7 inches, about 4.8 inches, about 4.9 inches, or about 5 inches).

[0015] In some embodiments, the inlet segment has a length of from about 0.5 inch to about 8 inches (e.g., about 0.5 inch, about 0.6 inch, about 0.7 inch, about 0.75 inch, about 0.8 inch, about 0.9 inch, about 1 .0 inch, about 1 .25 inches, about 1 .37 inches, about 1 .5 inches, about 1 .75 inches, about 2 inches, about 2.25 inches, about 2.5 inches, about 2.75 inches, about 3 inches, about 3.25 inches, about 3.5 inches, about 3.75 inches, about 4 inches, about 4.25 inches, about 4.5 inches, about 4.75 inches, about 5 inches, about 5.25 inches, about 5.5 inches, about 5.75 inches, about 6 inches, about 6.25 inches, about 6.5 inches, about 6.75 inches, about 7 inches, about 7.25 inches, about 7.5 inches, about 7.75 inches, or about 8 inches). In some embodiments, the outlet segment has a length of from about 0.01 inch to about 2.0 inches (e.g., about 0.01 inch, about 0.02 inch, about 0.03 inch, about 0.04 inch, about 0.05 inch, about 0.06 inch, about 0.07 inch, about 0.08 inch, about 0.09 about, about 0.1 inch, about 0.15 inch, about 0.2 inch, about 0.25 inch, about 0.3 inch, 0.35 inch, about 0.4 inch, about 0.45 inch, about 0.5 inch, about 0.55 inch, about 0.6 inch, about 0.65 inch, about 0.7 inch, about 0.75 inch, about 0.8 inch, about 0.85 inch, about 0.9 inch, about 0.95 inch, about 1 .0 inch, about 1 .05 inches, about 1 .1 inches, about 1.15 inches, about 1 .2 inches, about 1 .25 inches, about 1 .3 inches, about 1 .35 inches, about 1 .37 inches, about 1 .4 inches, about 1 .45 inches, about 1 .5 inches, about 1 .55 inches, about 1 .6 inches, about 1 .65 inches, about 1 .7 inches, about 1 .75 inches, about 1 .8 inches, about 1 .85 inches, about 1 .9 inches, about 1 .95 inches, or about 2.0 inches).

[0016] In some embodiments, the tube has an inner diameter from about 0.030 inch to about 0.040 inch (e.g., about 0.030 inch, about 0.031 inch, about 0.032 inch, about 0.033 inch, about 0.034 inch, ATTORNEY DOCKET NO: 51856-002WO2 PATENT about 0.035 inch, about 0.036 inch, about 0.037 inch, about 0.038 inch, about 0.039 inch, or about 0.040 inch). In some embodiments, the tube includes a tapered proximal end adjacent to the inlet and a tapered distal end adjacent to the outlet to facilitate insertion and removal of the guidewire. In some embodiments, the tube has a wall thickness of from about 0.003 inch to about 0.01 inch (e.g., about 0.003 inch, about 0.004 inch, about 0.005 inch, about 0.006 inch, about 0.007 inch, about 0.008 inch, about 0.009 inch, or about 0.01 inch).

[0017] In a second aspect, the invention provides a kit including a device as described herein (e.g., a device of the first aspect) and a guidewire capable of transmitting RF energy. In some embodiments, the guidewire includes an outer diameter of from about 0.014 inch to about 0.038 inch (e.g., about 0.014 inch, about 0.015 inch, about 0.016 inch, about 0.017 inch, about 0.018 inch, about 0.019 inch, about 0.020 inch, about 0.021 inch, about 0.022 inch, about 0.023 inch, about 0.024 inch, about 0.025 inch, about 0.026 inch, about 0.027 inch, about 0.028 inch, about 0.029 inch, about 0.030 inch, about

[0018] 0.031 inch, about 0.032 inch, about 0.033 inch, about 0.034 inch, about 0.035 inch, about 0.036 inch, about 0.037 inch, about 0.038 inch, or, e.g., from about 0.030 inch to about 0.038 inch). In some embodiments, the kit further includes a first fastener connectable to the inlet of the housing. In some embodiments, the kit further includes a second fastener connectable to the outlet of the housing. In some embodiments, the kit further includes a dilator and a sheath connectable to the outlet of the housing. In some embodiments, the kit further includes a catheter.

[0019] In a third aspect, the invention provides a method for transmitting RF energy to a guidewire by inserting the guidewire into and through the tube of a device as described herein (e.g., a device of the first aspect), thereby establishing and maintaining contact between the guidewire and the tube, and actuating an RF energy generator connected to the RF connector, thereby transmitting RF energy to the tube and the guidewire. In some embodiments, prior to actuating the RF energy generator, the method further includes contacting the guidewire with a tissue of a subject in need of tissue ablation.

[0020] In another aspect, the invention provides a system including an insulating shaft including a proximal end and a distal end and defining a lumen therethrough; a guidewire configured to be slidably disposed within the lumen, the guidewire configured to be advanced distally relative to the insulating shaft to expose a distal tip of the guidewire, the distal tip of the guidewire, when exposed, configured to deliver radiofrequency (RF) energy to a septum of a subject to perforate the septum; an electrosurgical interface coupled to the proximal end of the insulating shaft and a generator, the electrosurgical interface including a passage aligned with the lumen of the insulating shaft such that the guidewire can extend through the passage and the lumen of the insulating shaft, the electrosurgical interface configured to establish an electrical coupling between the generator and the guidewire by physical contact and to maintain the electrical coupling while the guidewire is advanced distal to the distal end of the insulating shaft; and an activation device configured to, in response to be activated when the distal tip is exposed, cause the generator to deliver RF current to the guidewire via the electrical coupling to cause the distal tip to deliver the RF energy to perforate the septum.

[0021] In another aspect, the invention provides a method including extending a distal end of a guidewire disposed within an insulating sheath a first distance distal to a distal end of the insulating sheath, the distal end of the guidewire and the distal end of the insulating sheath being disposed ATTORNEY DOCKET NO: 51856-002WO2 PATENT proximate to a septum of a heart of a patient, wherein a proximal portion of the guidewire is slidably disposed within a passage of an electrosurgical interface, the electrosurgical interface configured to establish an electrical coupling between a RF generator and the guidewire by physical contact and to maintain the electrical coupling while the distal tip of the guidewire is extended distal to the insulating sheath; disposing the distal tip of the guidewire against the septum; delivering, after disposing the distal tip of the guidewire against the septum, radiofrequency (RF) energy to the septum via the distal tip; further extending the distal tip of the guidewire distally while delivering the RF energy to form a perforation in the septum; and in response to extending the distal tip of the guidewire a second distance distal to the distal end of the insulating sheath, exposing at least a portion of a conductive outer region of the guidewire such that an exposed surface area of the portion of the conductive outer region reduces a RF current density around the distal tip of the guidewire.

[0022] DEFINITIONS

[0023] As used herein, any values provided in a range of values include both the upper and lower bounds, and any values contained within the upper and lower bounds.

[0024] By “about” is meant ±10% of a recited value.

[0025] By “arc” in meant a curved shaped. The term “arc” does not limit a shape to being circular or symmetric or asymmetric about a center point. In some embodiments, an arc is a circular arc or an elliptical arc. In some embodiments, an arc is parabolic or hyperbolic. In some embodiments, a plurality of arcs forms one or more waves (e.g., a sinusoidal wave). In some embodiments, one wave refers to the distance between subsequent crests of the wave or subsequent troughs of the wave.

[0026] By “bend” is a change or redirection in an otherwise straight tube to create a shape. For example, three bends may form a single arc within the middle segment of a tube with a shared inlet and outlet axis. A bend may have a non-zero bend angle relative to the center axis of a portion of the tube preceding it. For example, a bend of a tube located at the endpoint of an arc may have a bend angle (or, e.g., a degree of deflection) from about 0.1 degrees to about 10 degrees relative to the inlet axis, the outlet axis, or both thereof. In the same example, a bend of a tube located at the inflection point of an arc may have a bend angle from about 170 degrees to about 179 degrees where the angle is measured between the immediate adjacent sides relative to the inflection point (e.g., at 1 mm on either side of the bend). It will be understood that the angle of a bend at the inflection point of an arc varies along different points of the arc.

[0027] By “operably connected” is meant either directly connected to transmit RF energy or connected via a switch that when actuated allows or stops RF transmission.

[0028] BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG. 1 shows an image of a device having a longitudinal cross-section of the housing to display the tube, RF connector, and second fastener of the device. The inlet and outlet of the housing are also shown. The tube includes a proximal end and a distal end. The second fastener is connected to the outlet of the housing and the distal end of the tube. The RF connector is soldered to the tube to provide transmission of RF energy to the tube. ATTORNEY DOCKET NO: 51856-002WO2 PATENT

[0030] FIG. 2 shows a schematic of the device having a longitudinal cross-section of the housing to display the tube, RF connector, first fastener, and second fastener of the device.

[0031] FIG. 3 shows an image of the device equipped with additional components. The RF connector is connected to a switch by an RF cable. The switch is an RF pencil. The second fastener connects the device from the outlet of the housing to a dilator which is connected to a sheath. The guidewire enters the inlet of the housing.

[0032] FIGs. 4A-4C show schemes of exemplary tubes of the device. FIG. 4A shows the inlet or outlet of the tube being tapered. The three bends within the tube are also shown. FIGs. 4B and 4C show a longitudinal cross-sectional view of the tube having an inlet, inlet segment, a middle segment, an outlet segment, and an outlet. The tube is not shown to scale. The middle segment shown in FIGs. 4B and 4C has three bends which form an arc which is circular, as shown by the thin dashed line. FIG. 4B shows that the middle segment can be described by an arc length, an off-axis deflection, and a degree of curvature. The degree of curvature is measured between the first bend and last bend which form the endpoints of the arc. The off-axis deflection is measured relative to the inlet and outlet center axes which are coaxial, as shown by the bold dashed line. FIG. 4C shows the three bends each defined by a bend angle. The first bend angle and third bend angle are measured relative to the inlet and outlet center axes. The second bend angle is measured relative to the areas of the tube immediately adjacent to the inflection point of the arc. The bends and angles are not shown to scale.

[0033] FIGs. 5A-5C show a device including a switch for connecting the tube to the RF connector. FIG. 5A shows a schematic of the device including the switch. Actuation of the switch connects and disconnects the RF transmission. FIG. 5B shows circuitry for controlling RF transmission in the device. FIG. 5C shows a circuit diagram between the conductive RF pins of the RF cable and the circuitry.

[0034] DETAILED DESCRIPTION

[0035] The present invention provides devices, kits, and methods for the transmission of RF energy to a guidewire by providing a plurality of contact points between the guidewire and the device as compared with traditional RF transmission approaches or commercially available RF transmission instruments. In particular, kits and methods are provided that can transmit RF energy to a guidewire using physical contact between a guidewire and a tube to provide a consistent transfer of energy while maintaining the ability to safely advance and retract the guidewire with resistance. Other advantages of the device include that it is compatible with a wide range of commercial guidewires (e.g., of various diameters) and that it does not limit the length of the guidewire.

[0036] The invention provides a device to facilitate the transmission of RF energy to a guidewire. The device is configured to allow physical contact between the guidewire and a tube that is energizable with RF energy. The guidewire is able to slide within the tub while maintaining physical contact. Exemplary embodiments of the device are shown, e.g., in FIGs 1 -3. Briefly, the device includes a housing, a tube, and an RF connector. The housing includes an inlet and an outlet (see, e.g., FIG. 1 ). The tube is disposed between the inlet and the outlet (see, e.g., FIGs. 1 and 2) and includes an inlet segment, an outlet segment, and a middle segment disposed therebetween, wherein the middle ATTORNEY DOCKET NO: 51856-002WO2 PATENT segment of the tube includes a plurality of bends relative to the center axis of the inlet segment, outlet segment, or both thereof (see, e.g., FIGs. 4B and 4C). The tube and the RF connector transmit RF energy, e.g., through a direct connection or via a switch. The guidewire passing from the inlet through the tube and out the outlets contacts the tube to transmit RF energy from the RF connector to the guidewire.

[0037] Devices

[0038] Housing

[0039] Devices of the invention include a housing that is configured to cover the tube and RF connector of the invention, e.g., to reduce end user exposure to RF energy (see, e.g., FIGs. 1 -3). The holder may include structural features, such as one or more recesses, cutouts, or other similar openings, to accommodate and secure the other parts of the device, e.g., the RF connector, the tube, and / or the fasteners (see, e.g., FIGs. 1 and 2).

[0040] The housing includes an inlet and an outlet. In some embodiments, the inlet and the outlet are approximately coaxial. In some embodiments, the inlet and outlet are offset by about 5% of the inner diameter (e.g., about 4%, about 3%, about 2%, or about 1%). In some embodiments, the inlet and outlet are offset by about 0.002 inch (e.g., about 0.0019 inch, about 0.0018 inch, about 0.0017 inch, about 0.0016 inch, about 0.0015 inch, about 0.0014 inch, about 0.0013 inch, about 0.0012 inch, about 0.0011 inch, about 0.001 inch, about 0.0009 inch, about 0.0008 inch, about 0.0007 inch, about 0.0006 inch, about 0.0005 inch, about 0.0004 inch, about 0.0003 inch, about 0.0002 inch, or about 0.0001 inch).

[0041] In some embodiments, the length of the housing is from about 1 .5 inches to about 15.0 inches (e.g., from about 1 .5 inches to about 2.0 inches, from about 1 .5 inches to about 3.0 inches, from about 3.0 inches to about 3.5 inches, from about 3.0 inches to about 4.0 inches, from about 3.0 inches to about 4.5 inches, from about 3.0 inches to about 5.0 inches, from about 3.0 inches to about

[0042] 5.5 inches, from about 3.0 inches to about 6.0 inches, from about 3.0 inches to about 6.5 inches, from about 3.0 inches to about 7.0 inches, from about 3.0 inches to about 7.5 inches, from about 3.0 inches to about 8.0 inches, from about 3.0 inches to about 8.5 inches, from about 3.0 inches to about 9.0 inches, from about 3.0 inches to about 9.5 inches, from about 3.0 inches to about 10.0 inches, from about 3.0 inches to about 10.5 inches, from about 3.0 inches to about 11 .0 inches, from about 3.0 inches to about 11.5 inches, from about 3.0 inches to about 12.0 inches, from about 3.0 inches to about 12.5 inches, from about 3.0 inches to about 13.0 inches, from about 3.0 inches to about 13.5 inches, from about 3.0 inches to about 14.0 inches, from about 3.0 inches to about 14.5 inches, from about 4.0 inches to about 4.5 inches, from about 4.0 inches to about 5.0 inches, from about 4.0 inches to about 5.5 inches, from about 4.0 inches to about 6.0 inches, from about 4.0 inches to about

[0043] 6.5 inches, from about 4.0 inches to about 7.0 inches, from about 4.0 inches to about 7.5 inches, from about 4.0 inches to about 8.0 inches, from about 4.0 inches to about 8.5 inches, from about 4.0 inches to about 9.0 inches, from about 4.0 inches to about 9.5 inches, from about 4.0 inches to about 10.0 inches, from about 4.0 inches to about 10.5 inches, from about 4.0 inches to about 11 .0 inches, from about 4.0 inches to about 11.5 inches, from about 4.0 inches to about 12.0 inches, from about ATTORNEY DOCKET NO: 51856-002WO2

[0044] PATENT

[0045] 4.0 inches to about 12.0 inches, from about 4.0 inches to about 12.5 inches, from about 4.0 inches to about 13.0 inches, from about 4.0 inches to about 13.5 inches, from about 4.0 inches to about 14.0 inches, from about 4.0 inches to about 14.5 inches, from about 4.0 inches to about 15.0 inches, from about 5.0 inches to about 5.5 inches, from about 5.0 inches to about 6.0 inches, from about 5.0 inches to about 6.5 inches, from about 5.0 inches to about 7.0 inches, from about 5.0 inches to about 7.5 inches, from about 5.0 inches to about 8.0 inches, from about 5.0 inches to about 8.5 inches, from about 5.0 inches to about 9.0 inches, from about 5.0 inches to about 9.5 inches, from about 5.0 inches to about 10.0 inches, from about 5.0 inches to about 10.5 inches, from about 5.0 inches to about 11 .0 inches, from about 5.0 inches to about 11 .5 inches, from about 5.0 inches to about 12.0 inches, from about 5.0 inches to about 12.0 inches, from about 5.0 inches to about 12.5 inches, from about 5.0 inches to about 13.0 inches, from about 5.0 inches to about 13.5 inches, from about 5.0 inches to about 14.0 inches, from about 5.0 inches to about 14.5 inches, from about 5.0 inches to about 15.0 inches, e.g., about 1 .5 inches, about 1 .6 inches, about 1 .7 inches, about 1 .8 inches, about 1 .9 inches, about 2.0 inches, about 2.1 inches, about 2.2 inches, about 2.3 inches, about 2.4 inches, about 2.5 inches, about 2.6 inches, about 2.7 inches, about 2.8 inches, about 2.9 inches, about 3.0 inches, about 3.1 inches, about 3.2 inches, about 3.3 inches, about 3.4 inches, about 3.5 inches, about 3.6 inches, about 3.7 inches, about 3.8 inches, about 3.9 inches, about 4.0 inches, about 4.1 inches, about 4.2 inches, about 4.3 inches, about 4.4. inches, about 4.5 inches, about 4.6 inches, about 4.7 inches, about 4.8 inches, about 4.9 inches, about 5.0 inches, about 5.1 inches, about 5.2 inches, about 5.3 inches, about 5.4 inches, about 5.5. inches, about 5.6 inches, about 5.7 inches, about 5.8 inches, about 5.9 inches, or about 6.0 inches, about 6.1 inches, about 6.2 inches, about 6.3 inches, about 6.4 inches, about 6.5 inches, about 6.6 inches, about 6.7 inches, about 6.8 inches, about 6.9 inches, about 7.0 inches, about 7.1 inches, about 7.2 inches, about 7.3 inches, about 7.4 inches, about 7.5 inches, about 7.6 inches, about 7.7 inches, about 7.8 inches, about 7.9 inches, about 8.0 inches, about 8.1 inches, about 8.2 inches, about 8.3 inches, about 8.4 inches, about 8.5 inches, about 8.6 inches, about 8.7 inches, about 8.8 inches, about 8.9 inches, about 9.0 inches, about 9.1 inches, about 9.2 inches, about 9.3 inches, about 9.4 inches, about 9.5 inches, about 9.6 inches, about 9.7 inches, about 9.8 inches, about 9.9 inches, about 10.0 inches, about 10.1 inches, about 10.2 inches, about 10.3 inches, about 10.4 inches, about 10.5 inches, about 10.6 inches, about 10.7 inches, about 10.8 inches, about 10.9 inches, about 11 .0 inches, about 11 .1 inches, about 11 .2 inches, about 11 .3 inches, about 11 .4 inches, about 11 .5 inches, about 11 .6 inches, about 11 .7 inches, about 11 .8 inches, about 11 .9 inches, about 12.0 inches, about 12.1 inches, about 12.2 inches, about 12.3 inches, about 12.4 inches, about 12.5 inches, about 12.6 inches, about 12.7 inches, about 12.8 inches, about 12.9 inches, about 13.0 inches, about 13.1 inches, about 13.2 inches, about 13.3 inches, about 13.4 inches, about 13.5 inches, about 13.6 inches, about 13.7 inches, about 13.8 inches, about 13.9 inches, about 14.0 inches, about 14.1 inches, about 14.2 inches, about 14.3 inches, about 14.4 inches, about 14.5 inches, about 14.6 inches, about 14.7 inches, about 14.8 inches, about 14.9 inches, or about 15.0 inches). ATTORNEY DOCKET NO: 51856-002WO2 PATENT

[0046] In some embodiments, the wall thickness of the housing is from about 0.09 inch to about 0.11 inch (e.g., from about 0.09 inch to about 0.01 inch, from about 0.1 inch to about 0.11 inch, e.g., about 0.09 inch, about 0.1 inch, or about 0.11 inch).

[0047] In some embodiments, the housing includes a material selected from a group consisting of a non-conductive polymer, a polypropylene (PP), a polyethylene (PE), an acrylonitrile butadiene styrene (ABS), a thermoset polymer, ABS-like photoresin, a PP-like photoresin, any other photoresin, or any combination thereof. The material may be a medical grade material. In some embodiments, the housing is manufactured by molding (e.g., injection molding) or additive manufacturing (e.g., 3D printing). In some embodiments, the housing is manufactured as at least two separate parts that are joined after securing the tube and the RF connector within the housing.

[0048] In some embodiments, the inlet includes a first fastener (or, e.g., connection, fitting, or lock). In some embodiments, the outlet includes a second fastener (e.g., connection, fitting, or lock). In some embodiments, the first fastener and the second fastener include a Luer fastener (e.g., a male Luer fastener or a female Luer fastener). In some embodiments the first fastener is a female Luer fastener. In some embodiments, the second fastener is a male Luer fastener (e.g., a slip fitting or lock fitting).

[0049] In some embodiments, the housing encases the tube and the RF connector. The housing may include a first lumen that extends longitudinally from the inlet to the outlet. The first lumen may be sized and shaped to encase and secure the tube of the invention (see, e.g., FIGs. 1 and 2). The housing may include a second lumen that extends inward at an angle to meet the first lumen. The second lumen may not be coaxial with the first lumen. The second lumen may be sized and shaped to encase and secure the RF connector of the invention (see, e.g., FIGs. 1 and 2). The entrance of the second lumen may be sized to accommodate a connection to the RF connector (e.g., by way of an RF cable). In some embodiments, the RF connector is sized to accommodate an industry standard 2 mm touchproof adapter. In some embodiments, the minimum inner diameter of the second lumen is no smaller than the outer diameter of the RF connector. In some embodiments, the minimum inner diameter of the second lumen is 2 mm.

[0050] In some embodiments, the housing is ergonomically designed to facilitate guidewire positioning while reducing fatigue on the operator’s hand during use. For example, the housing may include a tapered center connecting a distal region of the housing to a proximal region of the housing designed to create a handle for the operator’s hand during use (see, e.g., FIGs. 1 -3).

[0051] RF Connector

[0052] Devices of the invention include an RF connector (e.g., RF pin) that is operably connected to the tube (e.g., by way of a connecting wire, by way of soldering a connecting wire, by way of welding, by way of a screw connection, by clamping, by way of alligator clips, by way of brazing, by way of a conductive liquid or paste, or by way of a switch) and that transmits RF energy (see, e.g., FIGs. 1 and 2). The RF connector of the invention may be any component suitable for transmitting RF energy (e.g., an RF pin or an RF cable). In some embodiments, the RF connector is sized to accommodate an industry standard 2 mm touchproof adapter. The RF connector may be electronically coupled to an ATTORNEY DOCKET NO: 51856-002WO2 PATENT

[0053] RF button on the handle. In some embodiments, the RF button is a switch that, when actuated (e.g., turned to an on-state), transmits RF energy from the RF generator to the RF connector. The RF button provides the user with a simple means of enabling and disabling transmission of RF energy to the RF connector of the device during use and enables compatibility with commonly used RF generators in medical settings. Once energized with RF energy, the RF connector transmits RF energy to the tube. Any suitable RF generator may be employed, and the RF connector may be any connector compatible with the RF generator.

[0054] Tube

[0055] Devices of the invention include a tube that is disposed between the inlet and outlet of the housing, that is operably connected to the RF connector, and that transmits RF energy (see, e.g., FIGs. 1 and 2). The tube is configured to allow physical contact with a guidewire as the guidewire slides within the tube. The tube may include an inlet segment, an outlet segment, and a middle segment disposed therebetween (see, e.g., FIGs. 4B and 4C). The middle segment of the tube includes a plurality of bends relative to the center axis of the inlet segment, outlet segment, or both thereof (see, e.g., FIGs. 4B and 4C). The guidewire passing from the inlet, through the bent tube, and out the outlet contacts the tube to transmit RF energy from the RF connector to the guidewire.

[0056] The tube may include a plurality of bends. In some embodiments, the plurality of bends includes from 3 to 32 bends (from 3 to 9 bends, from 3 to 8 bends, from 3 to 7 bends, from 3 to 6 bends, from 3 to 5 bends, from 3 to 4 bends, from 4 to 10 bends, from 4 to 9 bends, from 4 to 8 bends, from 4 to 7 bends, from 4 to 6 bends, from 4 to 5 bends, from 5 to 10 bends, from 5 to 9 bends, from 5 to 8 bends, from 5 to 7 bends, from 5 to 6 bends, from 6 to 10 bends, from 6 to 9 bends, from 6 to 8 bends, from 6 to 7 bends, from 7 to 10 bends, from 7 to 9 bends, from 7 to 8 bends, from 8 to 10 bends, from 8 to 9 bends, from 9 to 10 bends, from 3 to 10 bends, from 3 to 15 bends, from 3 to 20 bends, from 3 to 25 bends, from 3 to 30 bends, from 5 to 10 bends, from 5 to 15 bends, from 5 to 20 bends, from 5 to 25 bends, from 5 to 30 bends, from 10 to 15 bends, from 10 to 20 bends, from 10 to 25 bends, from 10 to 30 bends, from 10 to 32 bends, from 15 to 20 bends, from 15 to 25 bends, from 15 to 30 bends, from 15 to 32 bends, from 20 to 25 bends, from 20 to 30 bends, from 20 to 32 bends, from 25 to 30 bends, from 25 to 32 bends, from 30 to 32 bends, or, e.g., 3 bends, 4 bends, 5 bends, 6 bends, 7 bends, 8 bends, 9 bends, 10 bends, 11 bends, 12 bends, 13 bends, 14 bends, 15 bends, 16 bends, 17 bends, 18 bends, 19 bends, 20 bends, 21 bends, 22 bends, 23 bends, 24 bends, 25 bends, 26 bends, 27 bends, 28 bends, 29 bends, 30 bends, 31 bends, or 32 bends). In some embodiments, the number of bends in the plurality of bends is the same as the number of points of contact between the guidewire and the tube. For example, the plurality of bends may include three bends configured to provide three points of contact between the guidewire and the tube. An exemplary tube with three bends is shown, e.g., in FIGs. 4A-4C. The plurality of bends provides contact points between the guidewire and the tube to ensure transmission of RF energy between the tube and the guidewire. The bends provide a smooth transition between each segment of the tube to retain the ability to advance or retract the guidewire with sufficient friction for ease of deployment. Furthermore, the tube provides smooth movement of the guidewire during insertion and ATTORNEY DOCKET NO: 51856-002WO2 PATENT removal for a range of different diameter guidewires (e.g., guidewires including an outer diameter of from about 0.014 inch to about 0.038 inch).

[0057] In some embodiments, the plurality of bends forms the shape of the middle segment. In some embodiments, the plurality of bends forms one or more arcs. In some embodiments the plurality of bends forms one or more symmetrical arcs about a center point, one or more asymmetrical arcs, or a combination thereof. In some embodiments, the one or more arcs are circular and / or elliptical. In some embodiments, the one or more arcs are parabolic or hyperbolic. In some embodiments, the one or more arcs form one or more waves (e.g., a sinusoidal wave). In some embodiments, the plurality of bends of the tube forms four sinusoidal waves per inch of the middle segment of the tube. The plurality of bends may form any shape that provides a smooth transition between the portions of the tube before and after the bend. In some embodiments, the tube is fabricated to include the plurality of bends. In some embodiments, the plurality of bends of the tube are formed by cold working, hot working, computer numerically controlled (CNC) bending, hand working, additive manufacturing (e.g., sintering or metal 3D printing), welding, ram-type bending, roll bending, compression bending, and / or rotary draw bending. The tube may be any suitable, commercial tube. In some embodiments, the tube may include any material capable of undergoing cold working, hot working, computer numerically controlled (CNC) bending, hand working, additive manufacturing (e.g., sintering or metal 3D printing), welding, ram-type bending, roll bending, compression bending, and / or rotary draw bending. In some embodiments, the tube includes any material capable of RF transmission, such as stainless steel or an alloy thereof, tungsten, platinum, another metal, or a conductive polymer. The tube may include any non-corrosive, conductive material with a surface hardness greater than that of the guidewire while retaining a smooth finish. In some embodiments, the tube may include a material that is nonmagnetic and United States Pharmacopeia (USP) Class VI.

[0058] In some embodiments, the plurality of bends includes one or more bends each located at the endpoint of an arc having a bend angle (or, e.g., degree of deflection) of from 0.1 degree to about 10 degrees (e.g., from about 0.1 degree to about 9 degrees, from about 0.1 degree to about 8 degrees, from about 0.1 degree to about 7 degrees, from about 0.1 degree to about 6 degrees, from about 0.1 degree to about 5 degrees, from about 0.1 degree to about 4 degrees, from about 0.1 degree to about 3 degrees, from about 0.1 degree to about 2 degrees, from about 0.1 degree to about 1 degree, from about 0.1 degree to about 0.9 degree, from about 0.1 degree to about 0.8 degree, from about 0.1 degree to about 0.7 degree, from about 0.1 degree to about 0.6 degree, from about 0.1 degree to about 0.5 degree, from about 0.1 degree to about 0.4 degree, from about 0.1 degree to about 0.3 degree, from about 0.1 degree to about 0.2 degree, from about 0.5 degree to about 1 degree, from about 1 degree to about 10 degrees, from about 1 degree to about 9 degrees, from about 1 degree to about 8 degrees, from about 1 degree to about 7 degrees, from about 1 degree to about 6 degrees, from about 1 degree to about 5 degrees, from about 1 degree to about 4 degrees, from about 1 degree to about 3 degrees, from about 1 degree to about 2 degrees, from about 2 degrees to about 10 degrees, from about 2 degrees to about 9 degrees, from about 2 degrees to about 8 degrees, from about 2 degrees to about 7 degrees, from about 2 degrees to about 6 degrees, from about 2 degrees to about 5 degrees, from about 2 degrees to about 4 degrees, from about 2 degrees to about 3 ATTORNEY DOCKET NO: 51856-002WO2

[0059] PATENT degrees, from about 3 degrees to about 10 degrees, from about 3 degrees to about 9 degrees, from about 3 degrees to about 8 degrees, from about 3 degrees to about 7 degrees, from about 3 degrees to about 6 degrees, from about 3 degrees to about 5 degrees, from about 3 degrees to about 4 degrees, from about 4 degrees to about 10 degrees, from about 4 degrees to about 9 degrees, from about 4 degrees to about 8 degrees, from about 4 degrees to about 7 degrees, from about 4 degrees to about 6 degrees, from about 4 degrees to about 5 degrees, from about 5 degrees to about 10 degrees, from about 5 degrees to about 9 degrees, from about 5 degree to about 8 degrees, from about 5 degree to about 7 degrees, from about 5 degree to about 6 degrees, from about 6 degree to about 10 degrees, from about 6 degrees to about 9 degrees, from about 6 degrees to about 8 degrees, from about 6 degrees to about 7 degrees, from about 7 degrees to about 10 degrees, from about 7 degrees to about 9 degrees, from about 7 degrees to about 8 degrees, from about 8 degrees to about 10 degrees, from about 8 degrees to about 9 degrees, from about 9 degrees to about 10 degrees, e.g., about 0.1 degree, about 0.2 degree, about 0.3 degree, about 0.4 degree, about 0.5 degree, about 0.6 degree, about 0.7 degree, about 0.8 degree, about 0.9 degree, about 1 degree, about 1 .5 degrees, about 2 degrees, about 2.5 degrees, about 3 degrees, about 3.5 degrees, about 4 degrees, about 4.5 degrees, about 5 degrees, about 5.5 degrees, about 6 degrees, about 6.5 degrees, about 7 degrees, about 7.5 degrees, about 8 degrees, about 8.5 degrees, about 9 degrees, about 9.5 degrees, or about 10 degrees) relative to the inlet axis, the outlet axis, or both thereof. An example of a tube having one or more bends defined by bend angles located at the end points of an arc is shown in FIG. 4C (e.g., first angle / bend and third angle / bend of FIG. 4C).

[0060] In some embodiments, the plurality of bends includes one or more bends each located at an inflection point of an arc, where the one or more bends have a bend angle of from about 170 degrees to about 179 degrees (e.g., from about 170 degrees to about 178 degrees, from about 170 degrees to about 177 degrees, from about 170 degrees to about 176 degrees, from about 170 degrees to about 175 degrees, from about 170 degrees to about 174 degrees, from about 170 degrees to about 173 degrees, from about 170 degrees to about 172 degrees, from about 170 degrees to about 171 degrees, from about 171 degrees to about 179 degrees, from about 171 degrees to about 178 degrees, from about 171 degrees to about 177 degrees, from about 171 degrees to about 176 degrees, from about 171 degrees to about 175 degrees, from about 171 degrees to about 174 degrees, from about 171 degrees to about 173 degrees, from about 171 degrees to about 172 degrees, from about 172 degrees to about 179 degrees, from about 172 degrees to about 178 degrees, from about 172 degrees to about 177 degrees, from about 172 degrees to about 176 degrees, from about 172 degrees to about 175 degrees, from about 172 degrees to about 174 degrees, from about 172 degrees to about 173 degrees, from about 173 degrees to about 179 degrees, from about 173 degrees to about 178 degrees, from about 173 degrees to about 177 degrees, from about 173 degrees to about 176 degrees, from about 173 degrees to about 175 degrees, from about 173 degrees to about 174 degrees, from about 174 degrees to about 179 degrees, from about 174 degrees to about 178 degrees, from about 174 degrees to about 177 degrees, from about 174 degrees to about 176 degrees, from about 174 degrees to about 175 degrees, from about 175 degrees to about 179 degrees, from about 175 degrees to about 178 ATTORNEY DOCKET NO: 51856-002WO2

[0061] PATENT degrees, from about 175 degrees to about 177 degrees, from about 175 degrees to about 176 degrees, from about 176 degrees to about 179 degrees, from about 176 degrees to about 178 degrees, from about 176 degrees to about 177 degrees, from about 177 degrees to about 179 degrees, from about 177 degrees to about 178 degrees, 178 degrees to about 179 degrees, e.g., about 170 degrees, about 171 degrees, about 172 degrees, about 173 degrees, about 174 degrees, about 175 degrees, about 176 degrees, about 177 degrees, about 178 degrees, or about 179 degrees) measured between the immediate adjacent sides relative to the inflection point (e.g., at 1 mm on either side of the inflection point). It will be understood that the angle of a bend at the inflection point of an arc varies along different points of the arc. An example of a tube having one or more bends defined by bend angles located at the inflection point of an arc is shown in FIG. 4C (e.g., second angle / bend of FIG. 4C).

[0062] In some embodiments, the length of the inlet segment of the tube is from about 0.5 inch to about 8 inches (e.g., from 0.5 inch to about 0.75 inch, from about 0.5 inch to about 1 .0 inch, from about 0.5 inch to about 2.0 inch, from about 0.05 inch to about 3.0 inch, from about 0.05 inch to about 4.0 inch, from about 0.05 inch to about 5.0 inch, from about 0.05 inch to about 6.0 inch, from about 0.05 inch to about 7.0 inch, from about 0.05 inch to about 8.0 inch, from about 1 .0 inch to about 1 .25 inch, from about 1 .0 inch to about 1 .5 inch, from about 1 .0 inch to about 2.0 inches, from about 1 .0 inch to about 3.0 inches, from about 1 .0 inch to about 4.0 inches, from about 1 .0 inch to about 5.0 inches, from about 1 .0 inch to about 6.0 inches, from about 1 .0 inch to about 7.0 inches, from about 1 .0 inch to about 8.0 inches, from about 2.0 inches to about 3.0 inches, from about 2.0 inches to about 4.0 inches, from about 2.0 inches to about 5.0 inches, from about 2.0 inches to about 6.0 inches, from about 2.0 inches to about 7.0 inches, from about 2.0 inches to about 8.0 inches, from about 3.0 inches to about 4.0 inches, from about 3.0 inches to about 5.0 inches, from about 3.0 inches to about 6.0 inches, from about 3.0 inches to about 7.0 inches, from about 3.0 inches to about 8.0 inches, from about 4.0 inches to about 5.0 inches, from about 4.0 inches to about 6.0 inches, from about 4.0 inches to about 7.0 inches, from about 4.0 inches to about 8.0 inches, from about 5.0 inches to about 6.0 inches, from about 5.0 inches to about 7.0 inches, from about 5.0 inches to about 8.0 inches, from about 6.0 inches to about 7.0 inches, from about 6.0 inches to about 8.0 inches, from about 7.0 inches to about 8.0 inches, e.g., about 0.5 inch, about 0.6 inch, about 0.7 inch, about 0.75 inch, about 0.8 inch, about 0.9 inch, about 1 .0 inch, about 1 .25 inches, about 1 .37 inches, about 1 .5 inches, about 1 .75 inches, about 2 inches, about 2.25 inches, about 2.5 inches, about 2.75 inches, about 3 inches, about 3.25 inches, about 3.5 inches, about 3.75 inches, about 4 inches, about 4.25 inches, about 4.5 inches, about 4.75 inches, about 5 inches, about 5.25 inches, about 5.5 inches, about 5.75 inches, about 6 inches, about 6.25 inches, about 6.5 inches, about 6.75 inches, about 7 inches, about 7.25 inches, about 7.5 inches, about 7.75 inches, or about 8 inches).

[0063] In some embodiments, the length of the outlet segment of the tube is from about 0.01 inch to about 2.0 inches (e.g., from about 0.01 inch to about 0.025 inch, from about 0.01 inch to about 0.05 inch, from about 0.01 inch to about 0.75 inch, from about 0.01 inch to about 0.1 inch, from about 0.01 inch to about 0.5 inch, from about 0.01 inch to about 1 .0 inch, from about 0.025 inch to about 0.05 inch, from about 0.025 inch to about 0.075 inch, from about 0.025 inch to about 0.1 inch, from about ATTORNEY DOCKET NO: 51856-002WO2 PATENT

[0064] 0.05 inch to about 0.075 inch, from about 0.05 inch to about 0.1 inch, from about 0.075 inch to about 0.1 inch, from about 0.1 inch to about 0.25 inch, from about 0.1 inch to about 0.5 inch, from about 0.1 inch to about 1 .0 inch, from about 0.1 inch to about 1 .25 inches, from about 0.1 inch to about 1 .5 inches, from about 0.1 inch to about 1 .75 inches, from about 0.1 inch to about 2.0 inches, from about 0.25 inch to about 0.5 inch, from about 0.25 inch to about 0.75 inch, from about 0.25 inch to about 1 .0 inch, from about 0.25 inch to about 1 .25 inches, from about 0.25 inch to about 1 .5 inches, from about 0.25 inch to about 1 .75 inches, from about 0.25 inch to about 2.0 inches, from about 0.5 inch to about 0.75 inch, from about 0.5 inch to about 1 .0 inch, from about 0.5 inch to about 1 .25 inches, from about 0.5 inch to about 1 .5 inches, from about 0.5 inch to about 1 .75 inches, from about 0.5 inch to about 2.0 inches, from about 0.75 inch to about 1 .0 inch, from about 0.75 inch to about 1 .25 inches, from about 0.75 inch to about 1 .5 inches, from about 0.75 inch to about 1 .75 inches, from about 0.75 inch to about 2.0 inches, from about 1 .0 inch to about 1 .25 inches, from about 1 .0 inch to about 1 .5 inches, from about 1 .0 inch to about 1 .75 inches, from about 1 .0 inch to about 2.0 inches, from about 1 .25 inches to about 1 .5 inches, from about 1 .25 inches to about 1 .75 inches, from about 1 .25 inches to about 2.0 inches, from about 1 .5 inches to about 1 .75 inches, from about 1 .5 inches to about 2.0 inches, from about 1 .75 inches to about 2.0 inches, e.g., about 0.01 inch, about 0.02 inch, about 0.03 inch, about 0.04 inch, about 0.05 inch, about 0.06 inch, about 0.07 inch, about 0.08 inch, about 0.09 about, about 0.1 inch, about 0.15 inch, about 0.2 inch, about 0.25 inch, about 0.3 inch, 0.35 inch, about 0.4 inch, about 0.45 inch, about 0.5 inch, about 0.55 inch, about 0.6 inch, about 0.65 inch, about 0.7 inch, about 0.75 inch, about 0.8 inch, about 0.85 inch, about 0.9 inch, about 0.95 inch, about 1 .0 inch, about 1 .05 inches, about 1 .1 inches, about 1 .15 inches, about 1 .2 inches, about 1 .25 inches, about 1 .3 inches, about 1 .35 inches, about 1 .37 inches, about 1 .4 inches, about 1 .45 inches, about 1 .5 inches, about 1 .55 inches, about 1 .6 inches, about 1 .65 inches, about 1 .7 inches, about 1 .75 inches, about 1 .8 inches, about 1 .85 inches, about 1 .9 inches, about 1 .95 inches, or about 2.0 inches). In some embodiments, the combined length of the inlet segment and outlet segment is about 4 inches.

[0065] In some embodiments, where the middle segment of the tube includes a portion having an arc length of from about 1 inch to about 5 inches (e.g., from about 1 inch to about 1 .25 inch, from about 1 inch to about 1 .5 inches, from about 1 inch to about 1 .75 inches, from about 1 inch to about 2 inches, from about 1 inch to about 2.25 inches, from about 1 inch to about 2.5 inches, from about 1 inch to about 2.75 inches, from about 1 inch to about 3 inches, from about 1 inch to about 3.25 inches, from about 1 inch to about 3.5 inches, from about 1 inch to about 3.75 inches, from about 1 inch to about 4 inches, from about 1 inch to about 4.25 inches, from about 1 inch to about 4.5 inches, from about 1 inch to about 4.75 inches, from about 1 .25 inches to about 1 .5 inches, from about 1 .25 inches to about 1 .75 inches, from about 1 .25 inches to about 2 inches, from about 1 .25 inches to about 2.25 inches, from about 1 .25 inches to about 2.5 inches, from about 1 .25 inches to about 2.75 inches, from about 1 .25 inches to about 3 inches, from about 1 .25 inch to about 3.25 inches, from about 1 .25 inches to about 3.5 inches, from about 1 .25 inches to about 3.75 inches, from about 1 .25 inches to about 4 inches, from about 1 .25 inches to about 4.25 inches, from about 1 .25 inches to about 4.5 inches, from about 1 .25 inches to about 4.75 inches, from about 1 .25 inches to about 5 inches, from ATTORNEY DOCKET NO: 51856-002WO2 PATENT about 2.0 inches to about 2.25 inches, from about 2.0 inches to about 2.5 inches, from about 2.0 inches to about 2.75 inches, from about 2.0 inches to about 3 inches, from about 2.0 inches to about

[0066] 3.25 inches, from about 2.0 inches to about 3.5 inches, from about 2.0 inches to about 3.75 inches, from about 2.0 inches to about 4 inches, from about 2.0 inches to about 4.25 inches, from about 2.0 inches to about 4.5 inches, from about 2.0 inches to about 4.75 inches, from about 2.0 inches to about 5 inches, from about 3.0 inches to about 3.25 inches, from about 3.0 inches to about 3.5 inches, from about 3.0 inches to about 3.75 inches, from about 3.0 inches to about 4 inches, from about 3.0 inches to about 4.25 inches, from about 3.0 inches to about 4.5 inches, from about 3.0 inches to about 4.75 inches, from about 3.0 inches to about 5 inches, from about 4.0 inches to about

[0067] 4.25 inches, from about 4.0 inches to about 4.5 inches, from about 4.0 inches to about 4.75 inches, from about 4.0 inches to about 5 inches, from about 4.25 inches to about 4.5 inches, from about 4.25 inches to about 4.75 inches, from about 4.25 inches to about 5 inches, from about 4.5 inches to about 4.75 inches, from about 4.5 inches to about 5 inches, from about 4.75 inches to about 5 inches, e.g., about 1 inch, about 1 .1 inches, about 1 .2 inches, about 1 .3 inches, about 1 .4 inches, about 1 .5 inches, about 1 .6 inches, about 1 .7 inches, about 1 .8 inches, about 1 .9 inches, about 2 inches, about 2.1 inches, about 2.2 inches, about 2.3 inches, about 2.38 inches, about 2.4 inches, about 2.5 inches, about 2.6 inches, about 2.7 inches, about 2.8 inches, about 2.9 inches, about 3 inches, about 3.1 inches, about 3.2 inches, about 3.3. inches, about 3.4 inches, about 3.5 inches, about 3.6 inches, about 3.7 inches, about 3.8 inches, about 3.9 inches, about 4 inches, about 4.1 inches, about 4.2 inches, about 4.3 inches, about 4.4 inches, about 4.5 inches, about 4.6 inches, about 4.7 inches, about 4.8 inches, about 4.9 inches, or about 5 inches). The arc length is a measure of the length of an arc in the middle segment from a proximal end to a distal end of the arc (see, e.g., FIG. 4B). For example, as shown in FIG. 4B, the middle segment includes three bends that form an arc having a degree of curvature. In this embodiment, the arc length is measured from the first bend to the last bend which form the endpoints of the arc.

[0068] In some embodiments, the middle segment includes a portion having an off-axis deflection of from about 0.005 inch to about 0.020 inch (e.g., from about 0.05 inch to about 0.08 inch, from about 0.05 inch to about 0.011 inch, from about 0.05 inch to about 0.014 inch, from about 0.05 inch to about 0.017 inch, from about 0.08 inch to about 0.011 inch, from about 0.08 inch to about 0.014 inch, from about 0.08 inch to about 0.017 inch, from about 0.08 inch to about 0.020 inch, from about 0.11 inch to about 0.014 inch, from about 0.11 inch to about 0.017 inch, from about 0.11 inch to about 0.020 inch, from about 0.14 inch to about 0.017 inch, from about 0.14 inch to about 0.020 inch, from about 0.17 inch to about 0.020 inch, or, e.g., about 0.005 inch, about 0.006 inch, about 0.007 inch, about 0.008 inch, about 0.009 inch, about 0.010 inch, about 0.011 inch, about 0.012 inch, about 0.013 inch, about 0.014 inch, about 0.015 inch, about 0.016 inch, about 0.017 inch, about 0.018 inch, about 0.019 inch, or about 0.020 inch) from the center axis of the inlet segment the outlet segment, or both thereof. The off-axis deflection is measured from any point along the middle segment which yields a maximum distance between the middle segment and the center axis of the inlet segment, the outlet segment, or both thereof (e.g., the center, the proximal end, or the distal end of the middle segment). In some embodiments, the inlet axis and the outlet axis are approximately coaxial. For example, as is shown in ATTORNEY DOCKET NO: 51856-002WO2 PATENT

[0069] FIG. 4B, the off-axis deflection of an arc within the middle segment is measured from the vertex of the arc to the inlet axis (the same axis as the outlet axis), as this yields the maximum distance between the arc and the inlet and outlet axis. The arc may be based on a circle having a radius of from about 30 inches to about 50 inches (e.g., from about 35 inches to about 50 inches, from about 40 inches to about 50 inches, from about 45 inches to about 50 inches, from about 30 inches to about 45 inches, from about 35 inches to about 45 inches, from about 40 inches to about 45 inches, from about 30 inches to about 40 inches, from about 35 inches to about 40 inches, from about 30 inches to about 35 inches, e.g., about 30 inches, about 31 inches, about 32 inches, about 33 inches, about 34 inches, about 35 inches, about 36 inches, about 37 inches, about 38 inches, about 39 inches, about 40 inches, about 41 inches, about 42 inches, about 43 inches, about 44 inches, about 45 inches, about 46 inches, about 47 inches, about 48 inches, about 49 inches, or about 50 inches).

[0070] In some embodiments, the middle segment of the tube includes a portion having a degree of curvature of from about 2 degrees to about 10 degrees (e.g., from about 2 degrees to 4 degrees, from about 2 degrees to 6 degrees, from about 2 degrees to 8 degrees, from about 4 degrees to 6 degrees, from about 4 degrees to 8 degrees, from about 4 degrees to 10 degrees, from about 6 degrees to 8 degrees, from about 6 degrees to 10 degrees, from about 8 degrees to 10 degrees, e.g., about 2 degrees, about 3 degrees, about 4 degrees, about 5 degrees, about 6 degrees, about 7 degrees, about 8 degrees, about 9 degrees, or about 10 degrees). The degree of curvature is a measure of the central angle to the ends of an arc of the middle segment (see, e.g., FIG. 4B). For example, as shown in FIG. 4B, the middle segment includes three bends that form a symmetric arc, where the degree of curvature is measured from the first bend to the last bend which form the endpoints of the arc.

[0071] In some embodiments, the inner diameter of the tube is from about 0.030 inch to about 0.040 inch (e.g., from about 0.032 inch to about 0.040 inch, from about 0.034 inch to about 0.040 inch, from about 0.036 inch to 0.040 inch, from about 0.038 inch to about 0.040 inch, from about 0.032 inch to about 0.038 inch, from about 0.034 inch to about 0.038 inch, from about 0.036 inch to about 0.038 inch, from about 0.032 inch to about 0.036 inch, from about 0.034 inch to about 0.036 inch, e.g., about 0.030 inch, about 0.031 inch, about 0.032 inch, about 0.033 inch, about 0.034 inch, about 0.035 inch, about 0.036 inch, about 0.037 inch, about 0.038 inch, about 0.039 inch, or about 0.040 inch).

[0072] In some embodiments, the outer diameter of the tube is from about 0.1 inch to about 0.2 inch (e.g., from about 0.12 inch to about 0.2 inch, from about 0.14 inch to about 0.2 inch, from about 0.16 inch to about 0.2 inch, from about 0.18 inch to about 0.2 inch, from about 0.1 inch to about 0.18 inch, from about 0.12 inch to about 0.18 inch, from about 0.14 inch to about 0.18 inch, from about 0.16 inch to about 0.18 inch, from about 0.1 inch to about 0.16 inch, from about 0.12 inch to about 0.16 inch, from about 0.14 inch to about 0.16 inch, from about 0.1 inch to about 0.14 inch, from about 0.12 inch to about 0.14 inch, from about 0.1 inch to about 0.12 inch, e.g., about 0.1 inch, about 0.11 inch, about 0.12 inch, about 0.13 inch, about 0.14 inch, about 0.15 inch, about 0.16 inch, about 0.17 inch, about 0.18 inch, about 0.19 inch, or about 0.2 inch).

[0073] In some embodiments, the wall thickness of the tube is from about 0.003 inch to about 0.01 inch (e.g., from about 0.003 inch to about 0.004 inch, from about 0.003 inch to about 0.005 inch, from ATTORNEY DOCKET NO: 51856-002WO2 PATENT about 0.003 inch to about 0.006 inch, from about 0.003 inch to about 0.007 inch, from about 0.003 inch to about 0.008 inch, from about 0.003 inch to about 0.009 inch, from about 0.004 inch to about 0.005 inch, from about 0.004 inch to about 0.006 inch, from about 0.004 inch to about 0.007 inch, from about 0.004 inch to about 0.008 inch, from about 0.004 inch to about 0.009 inch, from about 0.004 inch to about 0.01 inch, from about 0.005 inch to about 0.006 inch, from about 0.005 inch to about 0.007 inch, from about 0.005 inch to about 0.008 inch, from about 0.005 inch to about 0.009 inch, from about 0.005 inch to about 0.01 inch, from about 0.006 inch to about 0.007 inch, from about 0.006 inch to about 0.008 inch, from about 0.006 inch to about 0.009 inch, from about 0.006 inch to about 0.01 inch, from about 0.007 inch to about 0.008 inch, from about 0.007 inch to about 0.009 inch, from about 0.007 inch to about 0.01 inch, from about 0.008 inch to about 0.009 inch, from about 0.008 inch to about 0.01 inch, from about 0.009 inch to about 0.01 inch, e.g., about 0.003 inch, about 0.004 inch, about 0.005 inch, about 0.006 inch, about 0.007 inch, about 0.008 inch, about 0.009 inch, or about 0.01 inch).

[0074] In some embodiments, the tube includes a tapered outer wall adjacent to the inlet of the housing to facilitate insertion and removal of the guidewire. In some embodiments, the tube includes a tapered outer wall adjacent to the outlet of the housing to facilitate insertion and removal of the guidewire.

[0075] Additional Components

[0076] Devices of the invention may include one or more additional components. For example, devices may include one or more fasteners that may be connected to the inlet and outlet of the housing. A first fastener may be connected to the inlet of the holder. A second fastener may be connected to the outlet of the holder. The fasteners affixed to the holder of the invention may be any suitable fastener, e.g., snaps, latches, buttons, clips, pipes, fittings, NPTs, slips, or Luer fasteners (or, e.g., Luer locks, Luer slips, or Luer connectors) which may be integrated into the holder or externally connected to the holder. In some embodiments, the first fastener and the second fastener include a Luer fastener (e.g., a male Luer fastener or a female Luer fastener). In some embodiments, the first fastener includes a female Luer fastener. In some embodiments, the second fastener includes a male Luer fastener (e.g., a slip fitting or lock fitting). In some embodiments, the Luer fastener has an Internation Organization for Standardization (ISO) standard of ISO 80369-7:2021 . In some embodiments, the inner and outer diameters of the inlet and the outlet of the housing are sized to conform to the Luer fasteners (e.g., to the ISO standard for the Luer fasteners).

[0077] In some embodiments, the first fastener is connected to the proximal end of the tube. In some embodiments, the first fastener provides an entrance to the tube. In some embodiments, the second fastener is connected to the distal end of the tube. In some embodiments, the second fastener provides an exit from the tube.

[0078] The fastener may enable securing and / or fastening of additional components to the device, e.g., a sheath, a dilator, a hemostatic valve, and / or a catheter (see, e.g., FIG. 3). In some embodiments the first fastener is a female Luer fastener. In some embodiments, the second fastener is a male Luer fastener (e.g., a slip fitting or lock fitting). In some embodiments, the first fastener (e.g., ATTORNEY DOCKET NO: 51856-002WO2 PATENT a female Luer fastener) allows in-line connection with other accessory items. Other accessory items may include a tubing set on stop cock to facilitate aspiration during use. In some embodiments, the second fastener (e.g., a male Luer fastener) allows connection to a dilator, wherein the dilator accompanies a sheath (e.g., access sheath). The dilator may include a dilator cap. The sheath may include a hemostatic valve to minimize air embolism and blood loss.

[0079] In some embodiments, an RF generator transmits RF energy to the RF connector. In some embodiments, the RF connector is connected to a switch (e.g., an RF pencil, e.g., a push-button electrosurgical pencil, e.g., a Bovie® electrosurgical push button pencil) by way of, e.g., a component capable of transmitting RF energy (e.g., an RF cable, an RF connector and cable assembly). The switch and the component capable of transmitting RF energy can be positioned such that they may not be in contact with the patient during use. In some embodiments, the switch, when actuated (e.g., switched to an on-state), transmits RF energy from the RF generator to the RF connector. The switch provides the user with a simple means of enabling and disabling transmission of RF energy to the RF connector of the device during use and enables compatibility with commonly used RF generators in medical settings. The switch may be incorporated into the housing or a separate component. An exemplary device including a switch in the housing is shown in Fig. 5A. The switch may interface with circuitry to control transmission of RF energy from the RF generator to the RF connector. Exemplary circuitry is shown in Figs. 5B-5C. The device may also include a switch to change mode of operation, e.g., between a cutting mode (e.g., using a continuous RF waveform) and a coagulation mode (e.g., using a pulsed RF waveform). Such a switch may be combined with an on-off switch or a separate switch from an on-off switch. Furthermore, such a switch to change modes may be connected to or external to the housing.

[0080] In some embodiments, the device includes circuitry to control one or more of the power, length of time of RF transmission, length of time between consecutive pulses, the maximum number of consecutive pulses, the maximum power transmitted, or a cool down period between pulses. Each function may be implemented in separate circuits, or circuitry may control two or more functions. For example, the device may include timer circuity to control the length of time of RF transmission, e.g., to limit a pulse to about 200 ms to 750 ms, e.g., 300 to 500 ms. The timer circuitry may allow for different lengths of time for consecutive pulses, e.g., about 300-400 ms, about 375 ms, and about 500 ms. The timer circuitry may also provide for a minimum time between pulses, e.g., about 1 to 5 s, e.g., about 2- 3 s. Circuitry may also limit the number of consecutive pulses, e.g., to 2 to 5 pulses, e.g., 3 pulses. For example, after a desired maximum number of pulses, circuitry may require a cool down period, e.g., about 10-60 s or at least 30 s. Circuitry may also be employed to limit total time of RF transmission, e.g., maximum of about 300-750 ms, about 500 ms, and / or maximum RF power, e.g., maximum of 12 to 20 W, e.g., maximum of about 15 W. When the maximum time or power is exceeded, the circuitry may interrupt RF transmission. In certain embodiments, circuitry has a ±10 ms tolerance for timing and / or ±1 W tolerance for power functions. ATTORNEY DOCKET NO: 51856-002WO2

[0081] PATENT

[0082] Kits

[0083] The invention features kits that include the device alone or the device with one or more of the additional components described herein, such as one or more fasteners, catheters, guidewires, sheaths (e.g., access sheaths and / or guiding sheaths), dilators, switches (e.g., RF pencils), and / or additional RF connectors. For example, the kit may include the device and a guidewire, as herein described. The kit may also provide equipment for providing vascular access (e.g., a vascular access micro puncture set and access sheath; see, e.g., U.S. Patent No. 11 ,027,104, the entirety of which is incorporated by reference).

[0084] In some embodiments, the guidewire includes an outer diameter of from about 0.014 inch to about 0.038 inch (e.g., about 0.014 inch, about 0.015 inch, about 0.016 inch, about 0.017 inch, about

[0085] 0.018 inch, about 0.019 inch, about 0.020 inch, about 0.021 inch, about 0.022 inch, about 0.023 inch, about 0.024 inch, about 0.025 inch, about 0.026 inch, about 0.027 inch, about 0.028 inch, about 0.029 inch, about 0.030 inch, about 0.031 inch, about 0.032 inch, about 0.033 inch, about 0.034 inch, about

[0086] 0.035 inch, about 0.036 inch, about 0.037 inch, about 0.038 inch, or, e.g., from about 0.030 inch to about 0.038 inch). Any suitable guidewire capable of transmitting RF energy may be employed with the invention. It will be understood that the proximal end of the guidewire will not have any coating to prevent transmission of RF energy from the tube to the guidewire. Guidewires are known in the art.

[0087] In some embodiments, the kit includes a module that connects between the device and the RF generator. The module includes circuitry to control one or more of the power, length of time of RF transmission, length of time between consecutive pulses, the maximum number of consecutive pulses, the maximum power transmitted, or a cool down period between pulses. Each function may be implemented in separate circuits, or circuitry may control two or more functions. For example, the device may include timer circuity to control the length of time of RF transmission, e.g., to limit a pulse to about 200 ms to 750 ms, e.g., 300 to 500 ms. The timer circuitry may allow for different lengths of time for consecutive pulses, e.g., about 300-400 ms, about 375 ms, and about 500 ms. The timer circuitry may also provide for a minimum time between pulses, e.g., about 1 to 5 s, e.g., about 2-3 s. Circuitry may also limit the number of consecutive pulses, e.g., to 2 to 5 pulses, e.g., 3 pulses. For example, after a desired maximum number of pulses, circuitry may require a cool down period, e.g., about 10-60 s or at least 30 s. Circuitry may also be employed to limit total time of RF transmission, e.g., maximum of about 300-750 ms, about 500 ms, and / or maximum RF power, e.g., maximum of 12 to 20 W, e.g., maximum of about 15 W. When the maximum time or power is exceeded, the circuitry may interrupt RF transmission.

[0088] One or more components of the kit may be supplied in a sterile condition. The device may be sterilized using ethylene oxide. The kit may also include a package insert that instructs a user of the kit, such as a physician, to perform the methods disclosed herein.

[0089] Methods of use

[0090] Also featured are methods of transmitting RF energy to a guidewire in connection with methods for ablating tissue (e.g., epicardial tissue, endocardial tissue, dermal tissue, nervous tissue, or, e.g., a tumor, a nodule, or other growths in the body) or blood vessels (e.g., arteries and / or veins) ATTORNEY DOCKET NO: 51856-002WO2 PATENT and methods for performing interventional radiology (e.g., to monitor tissue ablation in real-time). In one embodiment, the guidewire is energized to provide transseptal access. The device may be employed for both ablation or cutting and coagulation. The method is carried out using devices and / or kits disclosed herein.

[0091] The method includes inserting the guidewire into and through the tube of a device, as described herein, thereby establishing and maintaining contact between the guidewire and the tube. After inserting the guidewire, the method further includes actuating an RF energy generator connected to the RF connector, thereby transmitting radiofrequency energy to the tube and the guidewire. In some embodiments, the device includes a switch . Actuation of the switch energized the guidewire passing through the tube to transmit RF energy (see, e.g. FIG. 5B). The same switch or a second switch may be employed to switch between modes, such as cutting and coagulation modes.

[0092] In some embodiments, prior to actuating the RF generator connected to the RF connector, the method further includes contacting the guidewire with a tissue of a subject in need of tissue ablation. Once tissue ablation is complete, the method may include disabling the RF generator. A grounding pad may be coupled to the RF generator for attachment to a patient to provide a return path for the RF energy during RF energy transmission.

[0093] In some embodiments, after actuating the RF generator, the method further includes actuating a switch (e.g., on-switching the switch) connecting the RF connector to the RF generator. In some embodiments, the method further includes disabling the switch (e.g., turning off the switch), thereby preventing RF energy transmission to the RF connector, the tube, and the guidewire. In some embodiments, the length of time of transmitting RF energy to the guidewire may be controlled by on / off switching the switch. The length of time will typically be sufficient to ablate tissue and / or blood vessels of the subject.

[0094] In some embodiments, the RF energy may have a frequency range of about 20 Hertz (Hz) to about 300 GHz. The RF generator may be designed to work in a high impedance range. The RF generator may be designed to deliver RF energy in a monopolar mode. In one embodiment, the energy is delivered as a continuous wave at a frequency between about 400 kHz and about 550 kHz, such as about 460 kHz, a voltage of between 100 to 200 Vrms and a duration of up to 99 seconds. In some embodiments, pulsed or non-continuous RF energy is transmitted. Pulsed RF energy may have RF energy of not more than about 60 watts, a voltage from about 200 Vrms to about 400 Vrms and a duty cycle of about 5% to about 50% at about from slightly more than 0 Hz to about 10 Hz. In some embodiments, the RF energy does not include more than about 60 watts, a voltage from about 240 Vrms to about 300 Vrms and a duty cycle of 5% to 40% at 1 Hz, with possibly, the pulsed RF energy being transmitted for a maximum of 10 seconds. For example, the RF generator may be set to provide pulsed radio frequency energy of not more than about 50 watts, a voltage of about 270 Vrms, and a duty cycle of about 10% at 1 Hz. Alternatively, the pulsed RF energy may provide RF energy of not more than about 50 watts, a voltage of about 270 Vrms, and a duty cycle of about 30% at 1 Hz. Methods for utilizing an RF generator to transmit RF energy to a guidewire are known in the art (see, e.g., US Patent Nos. 7,947,040, 8,192,425, 8,679,107, 9,179,932, 9,510,900, 9,597,146, 10,631 ,915, ATTORNEY DOCKET NO: 51856-002WO2 PATENT and 12,016,619, the entire contents of which are incorporated by reference), which methods can be readily applied to the operation of the device of this disclosure.

[0095] In some embodiments, the device is operated in a pulsed manner, e.g., under control of circuitry that controls the number, power, duration, and spacing of pulses. Pulses may be ascending in power and / or duration. Methods may also employ a maximum number of pulses, e.g., 2 to 5, such as 3, before a cool down period is required, e.g., about 10-60 s or at least 30 s. Such methods advantageously ensure no arcing, controlled heating, and reliable puncture across tissue conditions.

[0096] Methods may employ use of a standard foot pedal for actuation, e.g., where the foot pedal actuation is required before a switch on the device can energize a guidewire. An exemplary operating profile is as follows:

Claims

ATTORNEY DOCKET NO: 51856-002WO2 PATENTCLAIMS1 . A device for transmitting radiofrequency (RF) energy to a guidewire comprising: a) a housing comprising an inlet and an outlet; b) a tube disposed between the inlet and the outlet and comprising an inlet segment, an outlet segment, and a middle segment disposed therebetween wherein the middle segment of the tube comprises a plurality of bends relative to the center axis of the inlet segment, outlet segment, or both thereof; and c) an RF connector operably connected to the tube; wherein the tube and the RF connector transmit RF energy, wherein the guidewire passing from the inlet, through the tube, and out the outlet contacts the tube to transmit RF energy from the RF connector to the guidewire.

2. The device of claim 1 , wherein the device further comprises: a) a first fastener connected to the inlet and b) a second fastener connected to the outlet.

3. The device of claim 2, wherein the first fastener and the second fastener each comprise a Luer fastener.

4. The device of claim 1 , wherein the housing encases the tube and the RF connector.

5. The device of claim 1 , wherein the inlet segment or the outlet segment does not comprise a bend.

6. The device of claim 1 , wherein the plurality of bends comprises from 3 to 32 bends.

7. The device of claim 1 , wherein the plurality of bends comprises three bends configured to provide three points of contact between the guidewire and the tube.

8. The device of claim 1 , wherein the plurality of bends form one or more waves, wherein the middle segment comprises four waves per inch of the middle segment.

9. The device of claim 1 , wherein the middle segment comprises a portion having a degree of curvature from about 2 degrees to about 10 degrees.

10. The device of claim 1 , wherein the middle segment comprises a portion having an off-axis deflection of from about 0.005 inch to about 0.020 inch from the center axis of the inlet segment, the outlet segment, or both thereof.11 . The device of claim 1 , wherein the middle segment comprises a portion having an arc length of from about 1 inch to about 5 inches.ATTORNEY DOCKET NO: 51856-002WO2PATENT12. The device of claim 1 , wherein the inlet segment has a length of from about 0.5 inch to about 8 inches.

13. The device of claim 1 , wherein the outlet segment has a length of from about 0.01 inch to about 2.0 inches.

14. The device of claim 1 , wherein the tube has an inner diameter from about 0.030 inch to about 0.040 inch.

15. The device of claim 1 , wherein the tube has an outer diameter from about 0.1 inch to about 0.2 inch.

16. The device of claim 1 , wherein the tube comprises a tapered outer wall adjacent to the inlet and a tapered outer wall adjacent to the outlet to facilitate insertion and removal of the guidewire.

17. The device of claim 1 , wherein the tube has a wall thickness of from about 0.003 inch to about 0.01 inch.

18. The device of claim 1 , further comprising a switch to allow or cease RF transmission between the RF connector and the tube.

19. The device of claim 1 , further comprising timer circuitry to control a time length of RF transmission to the tube.

20. The device of claim 19, wherein the timer circuitry further limits the number of consecutive pulses.21 . The device of claim 1 , further comprising control circuitry to limit a maximum power of RF transmitted to the tube or a maximum time length of RF transmission to the tube.

22. A kit for transmitting radiofrequency energy to a guidewire comprising: a) a device of cany one of claims 1 -21 ; and b) the guidewire capable of transmitting RF energy.

23. The kit of claim 22, wherein the guidewire comprises an outer diameter of from about 0.014 inch to about 0.038 inch.

24. The kit of claim 22, wherein the kit further comprises a first fastener connectable to the inlet of the housing.ATTORNEY DOCKET NO: 51856-002WO2PATENT25. The kit of claim 22, wherein the kit further comprises a second fastener connectable to the outlet of the housing.

26. The kit of claim 22, wherein the kit further comprises a dilator and a sheath connectable to the outlet of the housing.

27. The kit of claim 26, wherein the kit further comprises a catheter.

28. A method for transmitting RF energy to a guidewire comprising: a) inserting the guidewire into and through the tube of a device of any one of claims 1 -27, thereby establishing and maintaining contact between the guidewire and the tube; b) actuating an RF energy generator connected to the RF connector, thereby transmitting RF energy to the tube and the guidewire.

29. The method of claim 28, further comprising, prior to step b), contacting the guidewire with a tissue of a subject in need of tissue ablation.

30. A system comprising: an insulating shaft including a proximal end and a distal end and defining a lumen therethrough; a guidewire configured to be slidably disposed within the lumen, the guidewire configured to be advanced distally relative to the insulating shaft to expose a distal tip of the guidewire, the distal tip of the guidewire, when exposed, configured to deliver radiofrequency (RF) energy to a septum of a subject to perforate the septum; an electrosurgical interface coupled to the proximal end of the insulating shaft and a generator, the electrosurgical interface including a passage aligned with the lumen of the insulating shaft such that the guidewire can extend through the passage and the lumen of the insulating shaft, the electrosurgical interface configured to establish an electrical coupling between the generator and the guidewire by physical contact and to maintain the electrical coupling while the guidewire is advanced distal to the distal end of the insulating shaft; and an activation device configured to, in response to be activated when the distal tip is exposed, cause the generator to deliver RF current to the guidewire via the electrical coupling to cause the distal tip to deliver the RF energy to perforate the septum.31 . A method, comprising: extending a distal end of a guidewire disposed within an insulating sheath a first distance distal to a distal end of the insulating sheath, the distal end of the guidewire and the distal end of the insulating sheath being disposed proximate to a septum of a heart of a patient, wherein a proximal portion of the guidewire is slidably disposed within a passage of an electrosurgical interface, the electrosurgical interface configured to establish an electrical coupling between a RF generator and the guidewire byATTORNEY DOCKET NO: 51856-002WO2PATENT physical contact and to maintain the electrical coupling while the distal tip of the guidewire is extended distal to the insulating sheath; disposing the distal tip of the guidewire against the septum; delivering, after disposing the distal tip of the guidewire against the septum, radiofrequency (RF) energy to the septum via the distal tip; further extending the distal tip of the guidewire distally while delivering the RF energy to form a perforation in the septum; and in response to extending the distal tip of the guidewire a second distance distal to the distal end of the insulating sheath, exposing at least a portion of a conductive outer region of the guidewire such that an exposed surface area of the portion of the conductive outer region reduces a RF current density around the distal tip of the guidewire.

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