Methods, systems and devices for perforating tissue structures

Abstract

The described systems, devices and methods relate to a system that includes an electrosurgical interface electrically coupled to a generator, an energy delivery element electrically coupled to the electrosurgical interface, the energy delivery element configured to receive energy from the generator and form a puncture hole in tissue of a patient, and a return electrode electrically coupled to the patient and the generator.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 435,659, filed December 28, 2022, entitled "Methods, Systems, And Apparatuses for perforating tissue structures," and U.S. Provisional Patent Application No. 63 / 586,940, filed September 29, 2023, entitled "Methods, Systems, And Apparatuses for perforating tissue structures," the disclosures of each of which are incorporated herein by reference.

[0002] Technical Field

[0002] The embodiments described herein relate generally to medical devices for electrical energy delivery, and more particularly to systems, apparatus and methods for penetrating and traversing tissue structures, including, for example, performing an atrial septal puncture during a cardiac intervention. [Background technology]

[0003] background

[0003] Many medical procedures may require penetrating and puncturing tissue structures to access a treatment site or to create a pathway or connection between different anatomical structures. For example, cardiac interventions typically use a needle, catheter, or guidewire to penetrate and puncture the interatrial septum to access the left side of the heart, e.g., to evaluate or treat a cardiac abnormality. In some cases, the guidewire or catheter may be equipped with an energy delivery device that can deliver energy, such as radiofrequency (RF) energy, to a tissue structure, such as the septum, to penetrate and perforate it. Summary of the Invention [Problem to be solved by the invention]

[0004]

[0004] While there are existing systems capable of penetrating and traversing tissue structures, such systems suffer from various drawbacks. For example, such systems can cause unwanted damage to other areas of the heart from inadvertent perforation or can result in char or thrombus formation due to high operating temperatures. Such systems may also require complex connections between catheters, guidewires, and / or other energy delivery components and the electrosurgical generator. The costs associated with manufacturing many systems are also high. Therefore, further improvements to such systems exist. [Means for solving the problem]

[0005] overview In one embodiment, a guidewire includes a conductive distal tip configured to deliver radio frequency (RF) energy to a subject's septum to form a perforation through the septum. The guidewire includes a conductive core coupled to the distal tip, the conductive core configured to conduct the RF energy to the distal tip. The guidewire includes a conductive outer portion disposed near the distal tip, the conductive outer portion configured to be coupled to the distal tip via the conductive core. The guidewire includes an insulating collar disposed between the distal tip and the conductive outer portion. The guidewire is configured to extend distally from the insulated shaft a first distance to expose the distal tip and enable the distal tip to deliver the RF energy and form the perforation. The guidewire is further configured to extend distally from the insulated shaft a second distance greater than the first distance to expose the distal tip and at least a portion of the conductive outer portion to increase the exposed surface area of ​​the conductive portion of the guidewire and thereby reduce current density along the conductive portion.

[0006] In one embodiment, an apparatus includes an insulated shaft having a proximal end and a distal end and defining a lumen therethrough. The apparatus includes a guidewire configured to be slidably disposed within the lumen, the guidewire configured to be advanced distally relative to the insulated shaft to expose a distal tip of the guidewire, which, upon exposure, is configured to deliver radio frequency (RF) energy to a septum of a subject to form a perforation through the septum. The apparatus includes an electrosurgical interface coupled to the proximal end of the insulated shaft and to a generator, the electrosurgical interface including a passageway aligned with the lumen of the insulated shaft such that the guidewire can extend through the passageway and the lumen of the insulated shaft, the electrosurgical interface configured to establish an electrical coupling between the generator and the guidewire and to maintain the electrical coupling while the guidewire is advanced distally to the distal end of the insulated shaft. The device includes an actuator configured, in response to being actuated when the distal tip is exposed, to send a signal to the generator, causing the generator to generate and deliver a voltage output to the guidewire via the electrical coupling to deliver RF energy to the distal tip to form a perforation.

[0007] In one embodiment, a system includes a generator and an electrosurgical device. The electrosurgical device includes a guidewire configured to deliver radio frequency (RF) energy to a subject's septum and perforate therethrough. The electrosurgical device includes an electrosurgical interface configured to be coupled to the generator. The electrosurgical interface includes a passageway configured to slidably receive the guidewire such that the guidewire and the electrosurgical interface can move relative to one another. The electrosurgical interface is configured to establish an electrical coupling between the guidewire and the generator and to maintain the electrical coupling while the guidewire is moved relative to the electrosurgical interface. The generator is configured to generate and deliver a voltage output to the guidewire via the electrical coupling in response to receiving an activation signal, monitor a characteristic associated with the electrosurgical device, and modulate the voltage output based on the characteristic.

[0008] In one embodiment, a method includes extending a guidewire disposed within an insulating sheath a first distance distal to a distal end of the insulating sheath, wherein the guidewire and the insulating sheath are positioned proximate a tissue wall. The method includes positioning a distal tip of the guidewire in contact with the tissue wall. The method includes, after positioning the distal tip of the guidewire in contact with the tissue wall, delivering radio frequency (RF) energy to the tissue wall via the distal tip. The method includes further extending the guidewire distally while delivering the RF energy to form a perforation through the tissue wall. The method includes, in response to extending the guidewire a second distance distal to the distal end of the insulating sheath, exposing at least a portion of a conductive outer portion of the guidewire, thereby increasing the exposed conductive surface area of ​​the guidewire after forming the perforation.

[0009] In one embodiment, the energy delivery element is configured to perforate biological tissue. The energy delivery element includes a wire including a distal tip including a first conductive region, a first insulating region disposed immediately proximal to the conductive tip, and a second conductive region disposed immediately proximal to the first insulating region. When the energy delivery device is energized by a generator and at least partially contained within an insulating tube, the energy delivery device exhibits a current density that is a function of displacement relative to the distal end of the insulating tube.

[0010] When the distal tip, including the first conductive region, extends less than 10 mm beyond the end of the insulating tube, the current density is greater than 45 A / cm2 and less than 250 A / cm2. When the distal conductive tip extends 10 mm beyond the end of the insulating tube, the current density associated with the first conductive region is less than 60 A / cm2 and the current density associated with the second conductive region is less than 60 A / cm2. When the distal conductive tip extends 20 mm beyond the end of the insulating tube, the current density distributed from the first conductive region is in the range of less than 25 A / cm2 and the current density distributed from the second conductive region is less than 25 A / cm2.

[0011] In one embodiment, an electrosurgical interface includes a housing defining a lumen and containing a conductive element, the conductive element and the lumen being sized to slidably receive an energy delivery element. The electrosurgical interface includes an energized wire connected to the conductive element and an actuator that modulates energy delivered by the energized wire. When the actuator is in an energized state, radio frequency (RF) energy is transmitted through the conductive element to the energy delivery element. [Brief explanation of the drawings]

[0012] BRIEF DESCRIPTION OF THE DRAWINGS [Figure 1] 1 is a schematic diagram of an electrosurgical system according to an embodiment. [Figure 2]

[0013] FIG. 1 is a schematic diagram of an electrosurgical system showing components positioned relative to a patient, according to an embodiment. [Figure 3A]

[0014] 10A-10C illustrate schematically an interface for transferring electrical energy from an electrosurgical generator to an energy delivery element, according to an embodiment. [Figure 3B] 1 illustrates a schematic representation of an interface for transferring electrical energy from an electrosurgical generator to an energy delivery element, according to an embodiment. [Figure 3C] 1 illustrates a schematic representation of an interface for transferring electrical energy from an electrosurgical generator to an energy delivery element, according to an embodiment. [Figure 4]

[0015] 1 shows an example of an electrosurgical device, according to an embodiment. [Figure 5A]

[0016] 5 provides a top view of the electrosurgical interface of the electrosurgical device of FIG. 4. [Figure 5B]

[0016] A cross-sectional view of an electrosurgical interface is provided with a portion of the outer housing removed to show the internal components of the electrosurgical interface. [Figure 5C]

[0016] FIG. 5 shows a side cross-sectional view of the electrosurgical device of FIG. 4, illustrating the internal components of the electrosurgical interface. [Figure 6A]

[0017] 10 shows a top view of another example of an electrosurgical interface of an electrosurgical device, according to an embodiment. [Figure 6B] FIG. 6B shows a side view of the electrosurgical interface of FIG. 6A. [Figure 6C] FIG. 6B illustrates a top view of the electrosurgical interface of FIG. 6A, showing the internal components of the electrosurgical interface. [Figure 7A]

[0018] 10 shows a top view of another example of an electrosurgical interface of an electrosurgical device, according to an embodiment. [Figure 7B]FIG. 7B illustrates a top view of the electrosurgical interface of FIG. 7A, showing the internal components of the electrosurgical interface. [Figure 7C]

[0018] FIG. 1 shows a top view of an electrosurgical device showing placement of the electrosurgical device, according to an embodiment. [Figure 8A]

[0019] 1 shows an example of a guidewire for an electrosurgical device, according to an embodiment. [Figure 8B] 8B illustrates operation of the guidewire of FIG. 8A as it traverses a tissue structure, according to an embodiment. [Figure 8C] 8B illustrates operation of the guidewire of FIG. 8A as it traverses a tissue structure, according to an embodiment. [Figure 9A]

[0020] 10A-10C illustrate different examples of guidewires for electrosurgical devices, according to embodiments. [Figure 9B] 10A-10C illustrate different examples of guidewires for electrosurgical devices, according to embodiments. [Figure 10]

[0021] 1 is a schematic diagram of a handheld electrosurgical system, according to an embodiment. FIG. [Figure 11A]

[0022] 1 illustrates an example guidewire having openings in the insulating coating of the guidewire, according to an embodiment. [Figure 11B]

[0023] 1 illustrates an example guidewire having a spiral cut in the insulating coating of the guidewire, according to an embodiment. [Figure 12]

[0024] 10 is a flowchart illustrating a method of using an electrosurgical system, according to an embodiment. [Figure 13]

[0025] 10 is a flowchart illustrating a method of varying RF power being delivered to a guidewire, according to an embodiment. [Figure 14]

[0026] 10 is a flowchart illustrating a method of delivering RF power to a guidewire, according to an embodiment. [Figure 15A]

[0027] 10 illustrates an unintentional lesion being created by an electrosurgical device in a patient's heart, according to an embodiment. [Figure 15B]

[0027] An embodiment illustrates an unintended lesion being created by an electrosurgical device in a patient's heart. [Figure 16]

[0028] 1A and 1B illustrate schematically an electrosurgical device including a guidewire and a dilator, according to an embodiment. [Figure 17]

[0029] 1A and 1B illustrate schematically an electrosurgical device including a guidewire and a dilator, according to an embodiment. [Figure 18]

[0030] 18 shows the current density and temperature surrounding the electrosurgical device of FIGS. 16 and 17 as the guidewire is retracted into the dilator. [Figure 19]

[0031] 18 shows the current density and temperature surrounding the electrosurgical device of FIGS. 16 and 17 when the guidewire extends from the dilator and engages the septum. [Figure 20]

[0032] 18 shows the current density and temperature surrounding the electrosurgical device of FIGS. 16 and 17 when the guidewire extends from the dilator and is at the heart wall. [Figure 21]

[0033] 18 shows the current density and temperature surrounding the electrosurgical device of FIGS. 16 and 17 when the guidewire extends from the dilator and is positioned within the blood pool. [Figure 22]

[0034] 18 is a graph of the temperature over time of the electrosurgical device of FIGS. 16 and 17 when the device is in the septum. [Figure 23A]

[0035] 18 is a graph of the terminal voltage of the electrosurgical device of FIGS. 16 and 17 when the guidewire is in the septum at an insertion depth of 0.5 mm. [Figure 23B] 18 is a graph of the terminal current of the electrosurgical device of FIGS. 16 and 17 when the guidewire is in the septum at an insertion depth of 0.5 mm. [Figure 23C]18 is a graph of the terminal impedance of the electrosurgical device of FIGS. 16 and 17 when the guidewire is in the septum at an insertion depth of 0.5 mm. [Figure 24A]

[0036] 18 is a graph of the temperature of the electrosurgical device of FIGS. 16 and 17 when the guidewire is inserted through the septum and positioned against the heart wall (with myocardium) at an insertion depth of 21.1 mm. [Figure 24B]

[0036] Figure 18 is a graph of the temperature of the electrosurgical device of Figures 16 and 17 when the guidewire is inserted through the septum and positioned in the blood pool (without myocardium) at an insertion depth of 21.1 mm. [Figure 25A]

[0037] 18 is a graph of the terminal voltage of the electrosurgical device of FIGS. 16 and 17 when the guidewire is inserted through the septum and positioned against the heart wall (with myocardium) at an insertion depth of 21.1 mm. [Figure 25B]

[0037] Figure 18 is a graph of the terminal voltage of the electrosurgical device of Figures 16 and 17 when the guidewire is inserted through the septum and positioned in the blood pool (without myocardium) at an insertion depth of 21.1 mm. [Figure 25C]

[0037] A graph of the terminal voltage of the electrosurgical device of Figures 16 and 17 when the guidewire is inserted through the septum and positioned against the heart wall (with myocardium) and within the blood pool (without myocardium) at an insertion depth of 21.1 mm. [Figure 26A]

[0038] 18 is a graph of the terminal current of the electrosurgical device of FIGS. 16 and 17 when the guidewire is inserted through the septum and positioned against the heart wall (with myocardium) at an insertion depth of 21.1 mm. [Figure 26B]

[0038] Figure 18 is a graph of the terminal current of the electrosurgical device of Figures 16 and 17 when the guidewire is inserted through the septum and positioned in the blood pool (without myocardium) at an insertion depth of 21.1 mm. [Figure 26C]

[0038] A graph of the terminal current of the electrosurgical device of Figures 16 and 17 when the guidewire is inserted through the septum and positioned against the heart wall (with myocardium) and within the blood pool (without myocardium) at an insertion depth of 21.1 mm. [Figure 27A]

[0039] 18 is a graph of the terminal impedance of the electrosurgical device of FIGS. 16 and 17 when the guidewire is inserted through the septum and positioned against the heart wall (with myocardium) at an insertion depth of 21.1 mm. [Figure 27B]

[0039] Figure 18 is a graph of the terminal impedance of the electrosurgical device of Figures 16 and 17 when the guidewire is inserted through the septum and positioned in the blood pool (without myocardium) at an insertion depth of 21.1 mm. [Figure 27C]

[0039] A graph of the terminal impedance of the electrosurgical device of Figures 16 and 17 when the guidewire is inserted through the septum and positioned against the heart wall (with myocardium) and within the blood pool (without myocardium) at an insertion depth of 21.1 mm. [Figure 28A]

[0040] 1 is an example of a guidewire tip having an insulating collar, according to an embodiment. [Figure 28B]

[0040] An example of a guidewire tip having an insulating collar, according to an embodiment. [Figure 29]

[0041] 1A and 1B illustrate schematically an electrosurgical device including a guidewire and a dilator, the guidewire having an insulating collar, according to an embodiment. [Figure 30A]

[0042] 16 and 29 show the current density and temperature around the electrosurgical devices of FIG. 16 and FIG. 29 when the guidewire is in the septum. [Figure 30B]

[0042] The current density and temperature surrounding the electrosurgical devices of Figures 16 and 29 are shown when the guidewire is in the heart wall. [Figure 30C]

[0042] Figures 16 and 29 show the current density and temperature surrounding the electrosurgical devices when the guidewire is in the blood pool. [Figure 31A]

[0043] 1 illustrates an example of an insulating collar over a coil wire, according to an embodiment. [Figure 31B]

[0044] 1 illustrates an example of an insulating collar over a coil, according to an embodiment. [Figure 32]

[0045] 10 shows an example of an insulating collar on a guidewire, according to an embodiment. [Figure 33]

[0046] 1 illustrates an example of an insulated coil over a guidewire, according to an embodiment. [Figure 34]

[0047] 1 illustrates an example of a guidewire tip with an insulating collar, according to an embodiment. [Figure 35]

[0048] FIG. 10 is a schematic diagram of implementing temperature control at the tip of an energy delivery device, according to an embodiment. [Figure 36]

[0049] 18 shows the current density around the electrosurgical device of FIGS. 16 and 17 in the septum. [Figure 37]

[0050] 18 shows the current density around the electrosurgical device of FIGS. 16 and 17 when the dilator is retracted while the electrosurgical device is at the heart wall and in the blood pool. [Figure 38A]

[0051] 18 is a graph of the current density around the electrosurgical device of FIGS. 16 and 17 when a guidewire is placed against the septum, inserted through the septum, and placed against the heart wall (with myocardium). [Figure 38B]

[0051] A graph of the current density around the electrosurgical device of Figures 16 and 17 when a guidewire is placed against the septum, inserted through the septum, and placed in the blood pool (without myocardium). [Figure 39]

[0052] 16 and 29 show current densities around the electrosurgical devices of FIGS. 16 and 29 when the electrosurgical device is at the heart wall and when the dilator is being retracted while in the blood pool. [Figure 40]

[0053] 1 illustrates an example of a guidewire tip having marker bands, according to an embodiment. [Figure 41]

[0054] 41 shows a cross-sectional view of the guidewire of FIG. 40. [Figure 42A]

[0055] 1 shows a perspective view of a guidewire according to an embodiment. [Figure 42B]

[0055] A perspective view of a guidewire according to an embodiment is shown. [Figure 42C]

[0055] A perspective view of a guidewire according to an embodiment is shown. DETAILED DESCRIPTION OF THE INVENTION

[0013] Detailed Description

[0056] Various embodiments herein describe systems, devices, device components, and methods for penetrating and crossing tissue structures, including thin tissue structures such as the atrial septum. In particular, electrosurgical systems are configured to penetrate and cross thin tissue structures for biomedical applications. Aspects of these embodiments may provide safer, faster, or more convenient tissue penetration.

[0014]

[0057] An example use of the electrosurgical systems, assemblies, and devices described herein is to facilitate atrial septal puncture procedures (e.g., atrial crossing). Performing atrial septal puncture, also known as atrial crossing, is a necessary procedural step for countless cardiac interventions, including cardiac ablation for the treatment of arrhythmias such as atrial fibrillation and atrial flutter, occlusion of the left atrial appendage, and transcatheter repair of the mitral valve. These and other conditions affect millions of people worldwide. For transcatheter therapy of the left side of the heart, a large-diameter sheath and device (e.g., approximately 8-12 French) can be delivered to the right atrial chamber using a direct route from the large vena cava. After the catheter is delivered to the right side of the heart, a small puncture hole is created in the atrial septum, which divides the left and right sides of the heart, to access the left side of the heart. The atrial septum is composed of a thin, fibrous structure known as the fossa ovalis (FO).

[0015]

[0058] The most widely used technique for puncturing the septum is by inserting a long guide catheter over a guidewire into the heart. The guide catheter is manipulated to position its distal tip within the FO. Once the FO position is achieved and confirmed by fluoroscopy or ultrasound imaging, the guidewire is removed and replaced with a long, rigid needle known as a transseptal needle. Due to the transseptal needle's rigidity, manual shaping outside the body may be required to achieve the desired position within the FO. Using the transseptal needle, mechanical force is applied, causing the sharp distal tip of the needle to puncture the FO. Once a puncture hole is created, the transseptal needle is removed, and the guidewire is reinserted, with its distal tip advanced into the left atrium. With the guidewire in place, various therapeutic devices can be delivered to the left atrium based on the physician's preference and the proposed treatment.

[0016]

[0059] However, mechanical systems that rely on rigid needles have several drawbacks and may not always be effective at penetrating and puncturing the septum. Furthermore, such systems require additional components (e.g., a rigid needle) to facilitate puncturing and crossing the septum. In contrast, the electrosurgical systems described herein can effectively penetrate and puncture the septum and cross it to facilitate the delivery of other therapeutic devices.

[0017]

[0060] The electrosurgical systems, assemblies, and devices described herein offer several advantages. By combining the guiding and puncturing functions into a single tool or device, at least one device exchange can be eliminated. Each device exchange (i.e., removing one device from the patient's body and replacing it with another) increases the risk of undesirable events, such as air embolism leading to stroke, inadvertent puncture of the vasculature, or loss of device positioning resulting in extended procedure times. The distal end of the novel electrosurgical guidewire is flexible (e.g., sufficiently flexible to conform to the shape of the sheath and / or dilator), allowing it to be used with a steerable guide catheter or sheath without the need to remove the device from the body for manual shaping. The ability to steer and manipulate the flexible distal tip with the sheath facilitates precise positioning on the FO and optimal traverse location for various patient anatomies.

[0018]

[0061] Some electrosurgical systems use an electrosurgical guidewire that is inserted into a dilator and connected to an electrosurgical generator with a spring-loaded clip. The generator can apply RF energy to the distal tip of the electrosurgical guidewire when a button or footswitch on the generator is pressed. The electrosurgical systems described herein improve upon such electrosurgical systems in several ways. First, the electrosurgical systems described herein include an interface that couples the energy delivery element to the generator, where the energy delivery element can slide relative to a fixed electrode within the interface, thereby allowing the energy delivery element to be easily advanced or retracted. In some embodiments, the interface can be coupled to the rear of the energy delivery element to allow for easy steering. Second, energy delivery elements, such as guidewires, used in the systems described herein can be manufactured using batch processes for coating and plating, facilitating the production of lower-cost devices. Third, the systems described herein can include a button or other actuation mechanism physically close to the sheath, allowing a single user to control both the timing of electrosurgical energy delivery and the position of the guidewire from a single location. Furthermore, the actuation mechanism can be located on a single device as the electrosurgical energy connector or interface (instead of a generator control panel or footswitch coupled to the generator) so that a single cable can be used to provide the necessary electrical connection to the generator. Fourth, energy delivery elements, such as guidewires, used in the systems described herein can have a coiled design with a large surface area and, when plated with an efficient heat conductor such as gold, can have improved heat transfer, thereby reducing the operating temperature of the electrosurgical tip during treatment. This can reduce the risk of char or clot formation due to excessive temperatures. Fifth, the guidewires used in the systems described herein can have an insulating collar that allows the tip of the guidewire to direct RF energy during treatment.Sixth, given that the electrical connection between the generator and the electrosurgical device allows the physician to easily slide or move the guidewire without further interference, the physician can rely on tactile feedback (e.g., as a result of the behavior of the guidewire tip) to assess when the guidewire is in contact with the tissue surface.

[0019]

[0062] Further details about the electrosurgical systems, devices and methods described herein are provided in the following sections.

[0020] Electrosurgical systems and devices

[0063] 1 is a schematic diagram of an electrosurgical system 100 according to an embodiment. The electrosurgical system 100 includes a generator 110, an electrosurgical device or assembly 120, and a return electrode 130.

[0021]

[0064] The generator 110 can be configured to generate energy, such as, for example, radio frequency (RF) energy. The generator 110 can include a memory 112, a processor 114, an energy source 116, and an input / output device 118. In some embodiments, the generator 110 can be coupled to an external power source 102, such as, for example, a direct current (DC) power supply. The generator 110 can include a plug or adapter that can be used to plug into a socket. Alternatively, or in addition, the generator 110 can include an on-board power source, such as, for example, a battery.

[0022]

[0065] The memory 112 may include a database (not shown) and may be, for example, a random access memory (RAM), a memory buffer, a hard drive, an erasable programmable read-only memory (EPROM), an electrically erasable read-only memory (EEPROM), a read-only memory (ROM), flash memory, etc. The memory 112 may store instructions that cause the processor 114 to execute modules, processes, and / or functions associated with the system 100, such as voltage waveform generation and / or impedance monitoring, as further described below.

[0023]

[0066] The processor 114 may be any suitable processing device configured to run and / or execute a set of instructions or code. The processor may be, for example, a general-purpose processor, a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), a digital signal processor (DSP), etc. The processor may be configured to run and / or execute application processes and / or other modules, processes, and / or functions associated with the system and / or a network (not shown) associated with the system. The underlying device technology may be provided in a variety of component types, for example, metal-oxide-semiconductor field-effect transistor (MOSFET) technology such as complementary metal-oxide-semiconductor (CMOS), bipolar technology such as emitter-coupled logic (ECL), polymer technology (e.g., silicon-conjugated polymer and metal-conjugated polymer-metal structures), mixed analog and digital, etc.

[0024]

[0067] The energy source 116 can be configured to convert, store, and / or deliver energy, for example, in the form of a voltage waveform. In some embodiments, the energy source 116 can include an alternating current (AC) / DC switching power supply. In some embodiments, the energy source 116 can include one or more capacitors for storing energy from the power source. In some embodiments, the energy source 116 can be configured to generate and deliver a voltage waveform, for example, to the electrosurgical device 120. In some embodiments, the voltage waveform can be an oscillating sinusoidal RF waveform. The voltage waveform can have a frequency of about 200 kHz to about 1 MHz (including all subranges and values ​​therebetween). For example, the voltage waveform can have a frequency of about 350 kHz to about 500 kHz, or a frequency of about 450 kHz, in some applications. The voltage waveform can have a peak voltage of about 100 V to about 400 V (including all subranges and values ​​therebetween). For example, the voltage waveform can have a peak voltage of about 150 V to about 250 V, or a peak voltage of about 200 V, in some applications.

[0025]

[0068] The input / output device 118 can be configured to provide a communication interface between an operator and the system 100. The input / output device 118 can include one or more input and output devices. In some embodiments, the input devices of the input / output device 118 can include a touchscreen or other touch-sensitive device, a step switch, a foot pedal, a keypad, a keyboard, a button, a joystick, etc. In some embodiments, the output devices of the input / output device 118 can include one or more of a display device and an audio device. The display device can include at least one of a light-emitting diode (LED), a liquid crystal display (LCD), an electroluminescent display (ELD), a plasma display panel (PDP), a thin film transistor (TFT), and an organic light-emitting diode (OLED). The audio device can audibly output patient data, sensor data, system data, other data, alerts, warnings, etc. The audio device can include at least one of a speaker, a piezoelectric audio device, a magnetostrictive speaker, and / or a digital speaker.

[0026]

[0069] Generator 110 can be coupled to electrosurgical device 120 and return electrode 130. In use, signal generator 110 is configured to generate a voltage waveform for penetrating and puncturing tissue, such as the atrial septum. For example, generator 110 can be configured to generate and deliver a voltage waveform to electrosurgical device 120. Return electrode 130 can be coupled to the patient (e.g., positioned on the patient's back, torso, or an extremity such as a leg) to allow current to flow from electrosurgical device 120 through the patient and then to return electrode 130, providing a safe current return path from the patient.

[0027]

[0070] In some embodiments, the generator 110 can operate in a constant power mode with a typical setting of about 5 to about 25 W. In some embodiments, the generator 110 can implement feedback loop control, for example, via a controller of the generator or a controller operatively coupled to the generator. For example, the generator 110 (or controller) can include circuitry configured to determine the impedance of the circuit from the generator 110 to the electrosurgical device 120, to the return electrode 130, and back to the generator 110. A processor 114 or other processing circuitry within the generator 110 monitors the impedance of the circuit and adjusts the voltage output to a preset or predetermined power (P max ) can be configured to modulate the P max can be from about 5 W to about 100 W (including all subranges and values ​​therebetween). For example, P max The RF power can be about 45 W to about 55 W, or about 50 W. During electrosurgical treatment, the impedance of the circuit starts at about 1500 ohms but can then rise to 2000 ohms as the biophysical properties of the tissue target change. For example, the impedance can change as the energy delivery device or guidewire touches and penetrates the tissue and then reaches the blood pool. Thus, the generator 110 can be configured to monitor this change in impedance and adjust the parameters of the voltage waveform. In some embodiments, the generator 110 can be configured to modify the RF power based on the characteristics of the energy delivery element 124 (e.g., output current, current density, temperature, etc.). Some electrosurgical waveform generators may operate in a constant power control mode, for example, where the impedance of the circuit is continuously measured and the voltage of the RF waveform is adjusted to produce a fixed power. For example, in an application involving a generator set producing 50 W of constant power, the voltage of the voltage waveform may be increased to a maximum voltage V of 3000 V (peak-to-peak) or greater to produce 50 W of constant power with increasing tissue impedance. maxThe RF power can rise dramatically from 0.1 W to 0.2 W. This can create complications because any connected electrosurgical device must have sufficient electrical insulation to protect against dielectric breakdown or current leakage, which can be dangerous to the patient or operator at high voltages. The high voltages associated with these power-controlled electrosurgical generators can cause sparking and lightning at the tip of the guidewire, which can result in significant bubble, clot, and char formation. In the case of an intravascular device in the left atrium of the heart, this can lead to ischemic stroke or other complications. In some embodiments, the generator is configured to vary the RF power over time. For example, the generator can provide a first output for a first period of time, a second output for a second period of time, a third output for a third period of time, etc.

[0028]

[0071] Given the lower operating voltage of the generator 110 and the use of a feedback control scheme to maintain power below a predetermined peak power, the systems and devices described herein can be used with electrosurgical devices having smaller profiles. For example, operating the generator 110 at a lower voltage (e.g., between about 150 V and about 250 V) can enable the use of electrosurgical devices with smaller insulation or less insulating material. In particular, the ability of an insulated wire to withstand dielectric breakdown is directly related to the thickness of the insulation. Thus, lower voltages allow the use of electrosurgical wires with thinner insulating coatings. In some embodiments, the thickness of the guidewire coating can be negligible compared to the diameter of the guidewire core, thereby improving the mechanical properties of the energy delivery element 122. Furthermore, because the insulation is thin, it can be applied to the guidewire core by low-cost manufacturing techniques such as dip coating or spray coating.

[0029]

[0072] In some embodiments, the generator 110 can be configured to modulate the voltage output based on the temperature of the distal tip of the energy delivery element 124. As discussed above, using an RF-powered guidewire or needle to create an atrial septal defect (e.g., for transseptal access) can pose a thromboembolic risk by inadvertently generating char and / or coagulum. When tissue reaches a temperature above a threshold, char and coagulum are generated, thereby triggering protein denaturation, dehydration, and the thrombosis cascade. Maintaining the tip temperature below that threshold prevents char and coagulum formation, thus avoiding thromboembolic risk to the patient. Thus, in some embodiments, the generator 110 can be configured to deliver a voltage output to the energy delivery element 124 until a target setpoint temperature or range is reached. In some embodiments, the target setpoint temperature or range can be between about 55 degrees Celsius and about 80 degrees Celsius. In operation, RF output from the generator can be initiated by the user when the guidewire is positioned in the desired tissue contact area, for example, by activating an actuator (e.g., a button or slider that may be located on the electrosurgical interface 122, described below). The generator 110 can then deliver current to reach a target setpoint temperature. Avoiding temperatures above about 80 degrees Celsius can reduce or prevent the occurrence of char and coagulum formation. Further details of implementing temperature control are described with reference to FIG. 36. In one embodiment, the electrosurgical system includes both a power-limited generator and a low-voltage tip.

[0030]

[0073] Electrosurgical device or assembly 120 may include an electrosurgical interface 122, an energy delivery element 124, and a sheath 126. Although electrosurgical device 120 is described as a single device, it can be understood that each of electrosurgical interface 122, energy delivery element 124, and sheath 126 may be implemented as separate devices and / or components of two or more devices.

[0031]

[0074] The electrosurgical interface 122 establishes electrical connectivity between the generator 110 and the energy delivery element 124 while allowing slidable translation of the energy delivery element 124 therethrough. The electrosurgical interface 122 can be coupled to, connectable to, or include a cable that connects to the generator 110 and an interface that receives the energy delivery element 124. The interface 122 can include an electrical coupling element that is electrically connected to the generator 110 (e.g., via a cable), as shown in more detail in FIGS. 3A-3C . In one embodiment, the electrical coupling element is an electrode, and the electrosurgical interface 122 includes a layer of conductive fluid that is in electrical contact with the electrode. The energy delivery element 124 can then be received within the conductive fluid and electrically coupled to the electrode via the conductive fluid. The energy delivery element 124 is slidable within the conductive fluid without compromising its electrical coupling with the electrode. In some embodiments, the electrical coupling between the energy delivery element 124 and the electrosurgical interface 122 can include a direct coupling, a fluid coupling, an inductive coupling, etc. In some embodiments, the interface 122 can be electrically coupled to the end of the energy delivery element 124. Further details of the electrosurgical interface 122 are provided below with respect to Figures 3A-3C.

[0032]

[0075] In some embodiments, electrosurgical device 120 may include a button, slider, or other actuation device for establishing an electrical connection between generator 110 and electrosurgical interface 122. For example, a button or slider may be provided on electrosurgical device 120, e.g., near a location where a user can manipulate energy delivery element 124 and / or other components of electrosurgical device 120, and the button may be pressed or the slider may be slid to establish an electrical connection between generator 110 and an electrode of electrosurgical interface 122. Alternatively, or in addition, the button, slider, or other actuation device may be actuated to send a signal to generator 110, e.g., via a wired or wireless connection to generator 110. In some embodiments, the signal may be an activation (on or off) signal. In some embodiments, the signal may trigger generator 110 to send RF energy (e.g., a pulsed waveform) to electrosurgical device 120. In some embodiments, the signal can be a voltage signal, a current signal, or an impedance signal that can be communicated to generator 110, which can deliver an RF waveform to electrosurgical device 120 in response to receiving the signal. In some embodiments, electrosurgical interface 122 and generator 110 are configured to communicate to identify types and / or information regarding electrosurgical interface 122, generator 110, and / or energy delivery element 124. For example, generator 110 can determine whether energy delivery element 124 has been previously used for a procedure. In some embodiments, generator 110 may be configured to prevent reuse of energy delivery element 124 to reduce the possibility of contamination.

[0033]

[0076] In some embodiments, the electrosurgical interface 122 can include a cutting mechanism for removing a portion of the insulating jacket of the energy delivery element 124 for electrically coupling to the energy delivery element 124. In some embodiments, the electrosurgical interface 122 can include a button that, when activated, operates a cutting blade to expose a conductive portion of the energy delivery element 124.

[0034]

[0077] The energy delivery element 124 can include an electrode or other conductive element for applying energy to the tissue structure. In embodiments, the energy delivery element 124 is a wire (e.g., a guidewire) that includes a distal conductive tip that is used to apply energy to the tissue structure, thereby penetrating and puncturing the tissue structure. In some embodiments, the energy delivery element 124 includes a distal tip that can transition between different configurations or shapes, e.g., a curved configuration and a straight configuration. In some embodiments, the energy delivery element 124 can have a shape memory tip that automatically assumes a preset shape or configuration when withdrawn beyond a certain amount (e.g., from a sheath 126, as described below). For example, the energy delivery element 124 can have a shape memory tip that automatically curves or assumes a curved or atraumatic shape (e.g., when curved, the curved portion becomes the most distal portion of the energy delivery element 124, and therefore, the most distal portion is less sharp and less likely to damage off-target tissue). Alternatively or additionally, the guidewire can include a spring-tempered stainless steel section that can return to a predetermined shape upon release from a constraining sheath (such as a dilator, described below). In some embodiments, the energy delivery element 124 can include a coiled structure that is at least partially coated, for example, with an insulating layer. In some embodiments, the energy delivery element 124 can be formed from a metallic material and a polymeric material. In some embodiments, the energy delivery element 124 can include two or more coiled structures, for example, a coated coiled structure and an uncoated coiled structure. In some embodiments, the energy delivery element 124 can include an insulating coating near the tip. In some embodiments, the energy delivery element 124 can include a material (e.g., tantalum, tungsten, etc.) near the distal tip that provides radiopacity, echogenicity, and / or insulation.

[0035]

[0078] In some embodiments, the energy delivery element 124 can have a large active electrode area, for example, an active electrode area of ​​greater than about 1 cm, greater than 2 cm, greater than 3 cm, greater than 4 cm, greater than 5 cm, or greater than 10 cm, or from about 1 cm to about 20 cm (including all values ​​and subranges therebetween). The active electrode area can include the distal conductive tip of the energy delivery element 124 and the conductive outer portion of the energy delivery element 124, such as a conductive outer coil, plating, etc. A larger active electrode area can provide more cooling to the tip because the conductive / non-insulated areas of the guidewire can absorb or draw away heat. A larger active electrode area can also reduce the current density at the distal tip of the energy delivery device 124, thereby reducing the risk of forming lesions.

[0036]

[0079] In some embodiments, the energy delivery element 124 can include at least one sensor. The at least one sensor can be located at the tip of the guidewire, near the tip of the guide, at a distal portion, a proximal portion, etc. As used herein, proximal refers to the portion of the device or component closest to the surgeon, and distal refers to the portion closer to the patient's anatomy. The sensor can be configured to measure a property of the guidewire. For example, the sensor can be configured to measure temperature, current density, pressure, etc. In some embodiments, the sensor can be used to localize the tip in an electroanatomical mapping system that enables the guidewire to be positioned in the cardiac space. In some embodiments, the sensor can be a temperature sensor, such as a thermistor or thermocouple. In some embodiments, the sensor can be a bimetallic thermocouple, for example, with a weld between the outer coil wire and one or more core wires. The proximal junction of the coil and core wire can act as a bimetallic thermocouple. In some embodiments, the sensor can be a thermistor integrated into the coil of the guidewire. Sensors can be used to provide feedback to reduce or switch off power in response to out-of-range readings, thus improving the safety of the procedure.

[0037]

[0080] In some embodiments, the energy delivery element 124 can have a proximal length or portion that is coated with a thermal insulator and a distal length or portion that is uncoated. The coated portion can be grasped or manipulated by an operator (e.g., a surgeon) during an electrosurgical procedure. In some embodiments, the energy delivery element 124 can be formed of a material that allows a surgeon to quickly identify or recognize the energy delivery element 124. For example, the energy delivery element 124 can have a two-color design that includes a metallic distal colored portion and a non-conductive proximal colored portion. The metallic portion can extend along the energy delivery element 124 toward a set point (e.g., a midpoint) and act as a continuous conductor from the set point to the distal end of the guidewire. The metallic portion can include a metal coating or other conductive material that covers manufacturing artifacts from welding, heat setting, or molding and provides a consistent, smooth surface finish. In some embodiments, the metallic portion can include gold plated on stainless steel or another base material (e.g., tungsten). The proximal portion can have a polymer coating or other insulating material that insulates the energy delivery element 124. The polymer can be applied by extrusion, reflow soldering, or coating. Suitable examples of such insulating materials include polytetrafluoroethylene (PTFE), polyimide, and nylon. The metal portion and the proximal non-conductive portion can have the same or different lengths. Further details of example electrosurgical guidewires are described below with reference to Figures 8A-9B, 16, 17, 28A-29, 31A-34, and 40-42C.

[0038]

[0081] When used with an electrosurgical interface 122, a conductive portion of the energy delivery element 124 can be coupled to the electrosurgical interface 122 to enable energy transfer through the conductive core of the energy delivery element 124 to the distal tip of the energy delivery element 124. In some embodiments, the energy delivery element 124 can include stainless steel (e.g., a stainless steel core, a stainless steel outer coil, etc.) for conducting energy. In some embodiments, materials such as gold, platinum, and / or other highly conductive materials can be used to form and / or coat portions of the energy delivery element 124 to improve heat transfer and reduce operating temperatures at the tip of the energy delivery element 124 during a surgical procedure. For example, the energy delivery element 124 can be formed of and / or coated or plated with such materials. Optionally, materials such as tungsten, tantalum, etc. can be incorporated into the energy delivery element 124 for their radiopacity. In one embodiment, the energy delivery element 124 is a conductive metal wire, which can have a large surface area, coiled design, and is plated with a good thermal conductor, such as gold, to improve heat transfer and reduce the operating temperature of the tip, which can reduce the risk of char or clot formation due to excessive temperatures.

[0039]

[0082] A sheath 126 (e.g., an insulated shaft) can be used in conjunction with a guidewire or other energy delivery element 124. The sheath 126 comprises a cannula with a lumen sized to receive the energy delivery element 124 and allow sliding of the energy delivery element 124 along the axis of the sheath. The sheath 126 can provide support to the guidewire during advancement of the guidewire through the patient's anatomy. In some embodiments, the sheath 126 can be configured to constrain or shape the energy delivery element 124. For example, as described above, in some embodiments, the energy delivery element 124 can have a distal tip configured to transition between a curved configuration and a straight or linear configuration. The tip of the energy delivery element 124 can be formed of a shape-memory or spring-biased material that is straight when constrained by an outer sheath (e.g., the sheath 126) and curved when unconstrained. This can be desirable because the guidewire has an atraumatic shape, thereby avoiding accidental damage to nearby patient anatomy. The sheath 126 can then be used to constrain the energy delivery element 124 in a straight configuration so that the tip of the energy delivery element 124 can contact and perforate through the tissue structure as it advances distally a first distance along the length of the sheath, but curves as it advances further away where it is more likely to encounter off-target anatomical structures. Further details on these points are provided with reference to FIGS. 8A-8C and 42A-42C. In some embodiments, the sheath 126 can include or be used with a dilator. After the energy delivery element 124 has perforated or formed an opening in the tissue structure, the dilator can be advanced to expand the opening to facilitate the delivery of a secondary treatment device, such as an ablation catheter, sheath, or other medical device. In some embodiments, the electrosurgical system 100 includes a sheathless dilator.

[0040]

[0083] The energy delivery element 124 can be designed for universal compatibility with multiple types of sheaths, dilators, and / or other devices. In some embodiments, the energy delivery element 124 can be used with multiple types of sheaths 126. Thus, a surgeon or medical practitioner can select the appropriate sheath for use during a particular procedure without requiring any predetermined adaptation of the system to be used with the selected sheath.

[0041]

[0084] In some embodiments, the guidewire or other energy delivery element 124 can include an insulating collar disposed near the distal end of the energy delivery element 124. The insulating collar can have a length of about 2 mm to about 10 mm, including all subranges and values ​​therebetween. The insulating collar surrounds the conductive portion of the energy delivery element 124 near the distal end. In some embodiments, the collar can be disposed about 0.5 mm to about 3 mm, including all subranges and values ​​therebetween, from the distal end of the energy delivery element 124. In operation, as the energy delivery element 124 extends distally from the sheath, the conductive tip of the guidewire is exposed. Further extension of the energy delivery element 124 from the sheath then exposes the insulating collar of the energy delivery element 124. The insulating collar can act as an extension of the insulating sheath so that the total surface area of ​​the exposed conductive portion of the energy delivery element 124 remains small, thereby maintaining higher current density levels near the distal tip of the energy delivery element 124. This ensures that the distal tip of the energy delivery element 124 has sufficient energy to penetrate the septum when the energy delivery element 124 extends a short distance from the sheath. As the guidewire extends further from the sheath and is inserted across the septum into the blood pool (e.g., the left atrium), additional conductive portions of the energy delivery element 124 are exposed, thereby reducing the current density at the distal tip of the energy delivery element 124. This therefore reduces the risk that the energy delivery element 124 will contact the heart wall (e.g., myocardium) when positioned across the septum and potentially inadvertently cause damage thereto. Further details of the properties and operation of guidewires with insulating collars are described with reference to Figures 28A-42C.

[0042]

[0085] 2 is a schematic illustration of an electrosurgical system 200, according to an embodiment. Electrosurgical system 200 can be structurally and / or functionally similar to other electrosurgical systems described herein, including, for example, electrosurgical system 100. For example, electrosurgical system 200 can include an electrosurgical device 220 (e.g., structurally and / or functionally similar to electrosurgical device 120), an electrosurgical generator 210 (e.g., structurally and / or functionally similar to generator 110), and a return electrode 230 (e.g., structurally and / or functionally similar to return electrode 130).

[0043]

[0086] Similar to electrosurgical system 100, electrosurgical system 200 can be configured to penetrate and traverse thin tissue structures for biomedical applications. System 200 includes a generator 210, an interface 222 having electrical contacts attached to a fluid lumen of an intravascular sheath or dilator, a detachable guidewire 224 (e.g., an example of energy delivery element 124) that delivers electrosurgical energy to a treatment target (e.g., a tissue structure within a patient's body), and a return electrode 230 attached to the patient's body.

[0044]

[0087] In use, electrosurgical energy flows from the generator 210 into the patient's body to the exposed tip of the guidewire 224, which is in contact with the target tissue. The circuit is completed by a return electrode 230 attached to the patient's body, which may be located on the torso or an extremity, such as the patient's leg. In some embodiments, the electrosurgical generator 210, connected to the electrosurgical device 220, can generate an oscillating sinusoidal RF waveform having a frequency of approximately 450 kHz and a peak voltage of approximately 200 V. In some embodiments, the generator 210 can operate in a constant power mode, at a setting of approximately 5 W to approximately 25 W.

[0045]

[0088] In some embodiments, similar to generator 110, generator 210 can implement a feedback loop control scheme whereby generator 210 adjusts one or more parameters of the RF waveform based on measured impedance or other characteristics of the circuit. Generator 210 can include circuitry that monitors the electrical impedance of the circuit from generator 210 to electrosurgical device 220, to return electrode 230, and back to generator 210. Generator 210 (e.g., via an on-board processor or circuitry) can calculate the instantaneous power provided by the formula P=I*V, where P is power, I is current, and V is voltage. Generator 210 can adjust the RF waveform to a predetermined peak voltage (V peak ) and peak power (P peak ), and during electrosurgery, the peak voltage of the voltage waveform will not exceed V unless it exceeds a calculated instantaneous impedance value. peak In this case, the power can be set to P max V is reduced so that it remains below

[0046] Electrosurgical Interface

[0089] In some embodiments, electrosurgical interfaces as described herein can include a sliding contact design. More specifically, the electrosurgical interface can establish an electrical coupling between the generator and the guidewire while allowing the guidewire to slide or move within the interface. In existing sliding contact interfaces, the electrical coupling can be established through a conductor in physical contact that engages with a second contact, such as a metal wire or plate. This can result in drag and potential wear of the second contact when the two are moved relative to one another. In the case of electrosurgical guidewires, the contact or interaction portion can include a thin coating that is prone to wear and resulting particle generation. In intravascular applications, such particle generation can lead to patient injury and other complications. In the case of electrosurgical guidewires, friction between the contact portion and the second contact can also reduce the tactile response or feel of the catheter, resulting in an inability to engage a therapeutic target distal to the guidewire contact portion. To address these shortcomings, spring-loaded electrical contacts (e.g., electrosurgical interfaces) that clip onto the proximal end of the electrosurgical guidewire may be used. However, they require a physical clip or clamp to transmit the electrosurgical energy from the generator, which limits the degree of movement of the electrosurgical guidewire.

[0047]

[0090] The electrosurgical devices described herein can provide electrical coupling without direct or physical contact and / or clamps or springs, which are associated with the drawbacks discussed above. Figures 4-5C show an electrosurgical device 420 according to one embodiment. Figure 4 provides a perspective view of the electrosurgical device 420. Figures 5A and 5B show detailed views of the electrosurgical interface 422 of the electrosurgical device 420. Figure 5C shows a side view of the electrosurgical device 420, with breaks to better show the details of the various components of the electrosurgical device 420. The electrosurgical device 420 may be functionally and / or structurally similar to the electrosurgical device 120 of Figure 1.

[0048]

[0091] As shown in FIG. 4, electrosurgical device 420 includes an electrosurgical interface 422 (e.g., functionally and / or structurally similar to electrosurgical interface 122 of FIG. 1), a cable 442, a guidewire 424 (e.g., functionally and / or structurally similar to energy delivery element 124 of FIG. 1), and a dilator 426 (e.g., functionally and / or structurally similar to the sheaths and other dilators described herein).

[0049]

[0092] The electrosurgical interface 422 is electrically coupled to a cable 442, which may be electrically coupled to a generator, such as generator 110 of FIG. 1 . The electrosurgical interface 422 establishes an electrical connection between the generator and a conductive portion of a guidewire 424. As described with respect to FIG. 1 , the electrosurgical interface 422 may include a button or actuation device for switchably or selectively establishing an electrical connection between the generator and the guidewire 424. The electrosurgical interface includes a housing that is electrically insulated from the current-carrying components of the electrosurgical interface 422, allowing the electrosurgical interface 422 to be handled safely and comfortably. In some embodiments, the housing is formed of plastic. In some embodiments, the housing is approximately 1 to 2 inches long (including all values ​​and subranges therebetween).

[0050]

[0093] Electrosurgical interface 422 is configured to establish and maintain an electrical connection with guidewire 424 even as guidewire 424 moves or translates within electrosurgical interface 422. Electrosurgical interface 422 includes a fixed electrode connected to the output of a generator via cable 442. When guidewire 424 is inserted into the lumen of electrosurgical interface 422, the fixed electrode may contact a conductive portion of guidewire 424 and provide an electrical connection to the generator via cable 442. The structure of electrosurgical interface 422 is further described in more detail with respect to Figures 3A and 3B.

[0051]

[0094] Guidewire 424 includes a tip 424a located at the distal end of guidewire 424. Tip 424a of guidewire 424a is configured to apply energy to a tissue structure. Guidewire 424 may extend through electrosurgical interface 422, where an electrode or other conductive element of electrosurgical interface 422 electrically couples to the conductive portion of guidewire 424 to provide power from the generator to guidewire 424. The portion of guidewire 424 that may contact electrosurgical interface 422 may be conductive, while the portion of guidewire 424 that does not contact electrosurgical interface 422 may be insulated or non-conductive. Guidewire 424 is further described with respect to Figures 8A-9B.

[0052]

[0095] When so deployed, the guidewire 424 includes a portion that extends through the electrosurgical interface 422 and a portion that is disposed within the lumen of the dilator 426. Optionally, the tip 424a of the guidewire 424 can be configured to have a curved or J-shaped shape when unconstrained, e.g., when disposed outside the dilator 426, which may have sufficient rigidity to constrain the curved tip 424a. In use, the guidewire 424 can be advanced, for example, through a patient's vasculature in its unconstrained configuration. The electrosurgical interface 422 and dilator 426 can be loaded onto the guidewire 424, and the dilator 426 can be advanced through the patient's anatomy (e.g., through the vasculature and into the heart). The dilator 426 can insulate any conductive portion of the guidewire 424 disposed within the dilator 426 to protect the patient from undesired energy delivery. The tip 424a of the guidewire 424 has been advanced until it is positioned distal to the distal end of the dilator 426. As shown in FIG. 4 , the dilator 426 is configured to constrain the guidewire 424 in a straight configuration when the tip 424a of the guidewire 424 is substantially disposed within the dilator 426. Thus, the dilator 426 can have sufficient rigidity to maintain the tip 424a of the guidewire 424 in a straight configuration while within the dilator 426. In use, the tip 424a can remain relatively straight when advanced a first distance beyond the sheath and can curve when advanced a greater distance. The straight configuration of the guidewire 424 can correspond to a position for delivering energy via the tip 424a of the guidewire 424, as further described below with reference to FIG. 8B .

[0053]

[0096] In one embodiment, the dilator 426 is coupled to the electrosurgical interface 422 so that the dilator 426 moves in tandem with the electrosurgical interface 422. For example, the dilator 426 can be coupled to the electrosurgical interface 422 via a luer connection or similar partial rotary connector, although other types of connectors are known in the art. Because the dilator 426 is coupled to the electrosurgical interface 422, a user can advance and position the dilator 426 by pushing or moving the electrosurgical interface 422. In some embodiments, finer movement and / or control of the dilator 426 can also be enabled by manipulating an actuator (e.g., a knob, slider, etc.) that can extend or retract the dilator 426 relative to the electrosurgical interface 422, for example. In some embodiments, the dilator 426 can be used to dilate an opening created by a guidewire 424 that delivers energy to a target location.

[0054]

[0097] In the embodiment shown in FIG. 5A , the electrosurgical interface 422 includes a housing 422a, a button 422b, a dilator interface 422c (e.g., a coupler), and a cable portion 442a terminating in a cable plug 442b. The housing 422a houses the internal components of the electrosurgical interface 422 and insulates and protects the operator and patient from the electrical components of the electrosurgical interface 422a. In some embodiments, the housing 422a is formed from an insulating material, such as plastic, rubber, or the like. The housing 422a may have an ergonomic shape for ease of handling, for example, a narrow central portion to facilitate a firm grip. The button 422b is disposed on the housing 422a. When activated, the button 422b enables the guidewire 424 to receive energy, for example, from the generator 110 coupled to the electrosurgical interface 422. In some embodiments, the button 422b can be coupled to a processor or other device configured to control the delivery of energy to the guidewire 424. For example, actuation of button 422b can send a signal to the processor, which can then control the electrosurgical interface 422 to provide energy to the guidewire 424 for a predetermined amount of time. In some embodiments, when button 422b is pressed, energy is provided to the guidewire 424. Optionally, the circuit is broken when the button is released (e.g., using a spring-loaded button or slider, etc.). In such embodiments, pressing button 422b can establish an electrical connection between the electrosurgical interface 422 and the guidewire 424 and / or the generator, forming a closed circuit between these various electrical components in conjunction with the return electrode 130. In some embodiments, button 422b is a toggle switch, for example, that turns energy delivery to the guidewire 424 on and off. In such embodiments, the processor can be configured to control a toggle, and / or pressing the button can mechanically close a switch, thereby connecting the generator power source to the guidewire 424.

[0055]

[0098] The dilator interface 422c allows the dilator 426 to be selectively coupled to the electrosurgical interface 422. In some embodiments, the dilator interface 422c includes a locking mechanism that prevents the dilator 426 from separating from the electrosurgical interface 422. The dilator interface 422c further allows a continuous lumen to be established to receive the guidewire 424 so that the dilator 426, along with the electrosurgical interface 422, can be advanced over the guidewire during a surgical procedure. The electrosurgical interface 422 receives energy via a cable 442 that includes a cable portion 442a and a cable plug 442b. The cable portion 442a directs energy to the electrosurgical interface 422, while the cable plug 442b interfaces with the generator.

[0056]

[0099] As shown in the embodiment depicted in FIG. 5B, cable portion 442a is electrically coupled to conductive pathway 444. Conductive pathway 444 carries energy from cable 442 to electrode 448. In some embodiments, an hourglass structure can be disposed near electrode 448, and the hourglass structure can define at least a portion of a lumen that receives guidewire 424. Electrode 448 allows guidewire 424 to slide within the guidewire lumen while maintaining constant electrical coupling between electrode interface 422 and guidewire 424. In some embodiments, electrical coupling between electrode interface 422 and guidewire is established via a conductive fluid similar to that described with reference to FIG. 3 above. For example, the conductive fluid can fill a space (e.g., a chamber) around guidewire 424 and electrode 448 to provide lubrication / reduce friction and establish electrical conductivity. In some embodiments, the electrode is electrically coupled to the guidewire via a spring. The spring can apply pressure to the electrode such that constant electrical coupling is maintained while allowing the guidewire to translate relative to the spring.

[0057]

[0100] In some embodiments, electrosurgical interface 422 can include an additional port 422d. Port 422d can be configured to couple one or more other devices, for example, to flush the chamber or guidewire lumen with a fluid, etc. In some embodiments, port 422d can also be configured to receive a guidewire 424.

[0058]

[0101] Figure 5C shows the guidewire 424 extending through the electrosurgical interface 422 and the dilator 426. The guidewire 424 extends through interface 422d, contacts the electrode 448, and extends through the dilator interface 422c and the dilator 426. In the configuration of Figure 5C, the guidewire 424 is shown retracted within the dilator 426. As mentioned above, in operation, the tip 424a of the guidewire 424 can be extended and positioned distally relative to the distal end of the dilator 426 so that the guidewire 424 can optionally form a J-shape (or other atraumatic shape).

[0059]

[0102] Figures 6A-6C show an electrosurgical interface 522 (e.g., functionally and / or structurally similar to electrosurgical interface 122 of Figure 1 and / or electrosurgical interface 422 of Figures 4-5C) according to an embodiment. Figure 6A shows a top view of electrosurgical interface 522. Figure 6B shows a side view of electrosurgical interface 522. Figure 6C shows a top view of electrosurgical interface 522, showing the internal components of the electrosurgical interface.

[0060]

[0103] Similar to electrosurgical interface 422, electrosurgical interface 522 is configured to establish an electrical connection with a guidewire (e.g., functionally and / or structurally similar to energy delivery element 124 of FIG. 1 ) and to maintain that connection while the guidewire is moved or translated within electrosurgical interface 522. Electrosurgical interface 522 includes a housing 522a (e.g., functionally and / or structurally similar to housing 422a of Figures 5A-5C), an actuator 522b (e.g., functionally and / or structurally similar to button 422b of Figures 5A-5C), an expander interface or coupler 522c (e.g., functionally and / or structurally similar to coupler 422c of Figures 5A-5C), a cable portion 542a (e.g., functionally and / or structurally similar to cable portion 442a of Figures 5A-5C), a cable plug 542b (e.g., functionally and / or structurally similar to cable plug 442b of Figures 5A-5C), and an additional port 522d (e.g., functionally and / or structurally similar to additional port 522d of Figures 5B and 5C).

[0061]

[0104] The actuator 522b of the electrosurgical interface 522 is a sliding actuator that, in operation, translates from a first position (e.g., an unactuated position) to a second position (e.g., an actuated position). In some embodiments, the first position can be a proximal position, and the second position can be a distal position. Although the actuator 522b is a sliding actuator, the actuator 522b can function similarly to the button 422b described above with reference to FIGS. 5A-5C. For example, in the distal or actuated position, the actuator 522b can cause electrical energy to be delivered to a guidewire disposed within the electrosurgical interface 522. In some embodiments, the actuator 522b can generate a signal that triggers an electrosurgical generator (e.g., generator 110) to deliver energy (e.g., a voltage waveform) to the electrosurgical interface, which then delivers energy to the guidewire. In some embodiments, the actuator 522b may provide haptic feedback (e.g., a vibration, a click, etc.) to the user during operation, for example, when the actuator 522b moves to a position that causes energy to be delivered to the guidewire. In some embodiments, the actuator 522b may not be a slide actuator. For example, the actuator 522b may be a button or another type of actuated component that can be pressed to activate energy delivery. In some embodiments, operating the actuator 522b may involve multiple movements. For example, to activate energy delivery to the guidewire, the actuator 522b may need to first be translated and then pressed to activate energy delivery. In some embodiments, the actuator 522b is spring-loaded so that the actuator 522b returns to its unactuated position when the user is no longer applying force to the actuator 522b.

[0062]

[0105] The housing 522a can be configured to be grasped by a user (e.g., a surgeon) during use. The surgeon can, for example, use one hand to hold the housing 522a and the other hand to hold and move (e.g., advance and / or retract distally) a guidewire disposed within the electrosurgical interface. As shown in FIGS. 6A and 6B , in some embodiments, the cable portion 542a can be positioned along the housing in a position that does not interfere with the user when holding the housing 522a. For example, as shown in FIG. 6B , the cable portion 542a can be positioned rearward of the housing 522a and can extend at an angle away from the housing 522a. Similar to the cable 442a, the cable 522a can include a plug or connector 542b that can be plugged or otherwise coupled to a generator (e.g., generator 110) to receive energy from the generator and send a signal to the generator (e.g., to trigger energy delivery). In some embodiments, the position of cable portion 542a can be reconfigurable to allow for a first configuration for a left-handed user and a second configuration for a right-handed user.

[0063]

[0106] As shown in FIG. 6C , the internal components and arrangement of electrosurgical interface 522 can be similar to those of electrosurgical interface 422. For example, electrosurgical interface 522 includes an electrode 548 (e.g., structurally and / or functionally similar to electrode 448 of FIG. 5C ) wired to a generator via cable components 542 a, 542 b. Electrode 548 can be electrically coupled to a guidewire disposed within a lumen 529 defined in part by or adjacent to electrode 548, e.g., via a conductive fluid disposed within the lumen (e.g., similar to that described with respect to FIG. 3 ). As described in detail in subsequent figures of the guidewire, the guidewire can include a conductive portion configured to be disposed within the conductive fluid within the lumen, enabling the guidewire to receive energy delivered by the generator to the electrode via the conductive fluid. The guidewire can have a conductive surface region coupled to its conductive core that can carry energy to the distal tip of the guidewire, e.g., for perforating tissue. A guidewire can be received through port 522d and can extend through electrosurgical interface 522. Electrosurgical interface 522 can also include a dilator interface or coupler 522c that can couple to a dilator or sheath (e.g., sheath 126 or dilator 426).

[0064]

[0107] As an alternative to the sliding contact embodiment described with reference to Figures 3A-6C, the electrosurgical interface can be configured to couple to the distal end of the guidewire, for example, via a physical attachment between the electrical port and the guidewire. In such an embodiment, the proximal end of the guidewire can be received within the electrosurgical interface and physically engage with an electrode or other conductive component wired to the generator (e.g., via an electrical circuit). The proximal end of the guidewire may include a conductive region such that energy (e.g., RF current) can be delivered through the guidewire to the distal end of the guidewire, for example, to penetrate and perforate tissue. Movement of the guidewire relative to the electrosurgical interface may be more limited than in the sliding contact embodiment described above.

[0065]

[0108] 7A-7C show an example of an electrosurgical interface 622 that can be configured to receive the proximal end of a guidewire, for example, to establish an electrical coupling between the guidewire and a generator (e.g., generator 110), according to an embodiment. Electrosurgical interface 622 can include components structurally and / or functionally similar to electrosurgical interface 122 of FIG. 1 or other electrosurgical interfaces described herein. FIG. 7A shows a top view of electrosurgical interface 622. FIG. 7B shows a top view of electrosurgical interface 622, illustrating the internal components of the electrosurgical interface. FIG. 7C shows a top view of an electrosurgical device 620 (e.g., structurally and / or functionally similar to electrosurgical device 120 of FIG. 1) including electrosurgical interface 622, according to an embodiment.

[0066]

[0109] As shown in Figure 7A, electrosurgical interface 622 includes a housing 622a (e.g., functionally and / or structurally similar to housing 422a of Figures 5A-5C), a button 622b (e.g., functionally and / or structurally similar to button 422b of Figures 5A-5C), and a cable 642a (e.g., functionally and / or structurally similar to cable portion 642a of Figures 5A-5C). As shown in Figure 7B, electrosurgical interface 622 further includes a port or opening 622c and an electrode 648 disposed on a circuit board 644 that can be electrically coupled to a generator. Cable 642 is operatively coupled to electrosurgical interface 622a via circuit 644 to provide electrical energy to the guidewire via electrode 648.

[0067]

[0110] Port 622c is configured to receive a guidewire (e.g., functionally and / or structurally similar to energy delivery element 124 of FIG. 1 ) to allow the guidewire to physically engage electrode 648. Electrosurgical interface 622 may include a coupling element (e.g., a clip, fastener, etc.) that may be configured to hold onto the guidewire, for example, to maintain the guidewire in place within the port after it is received within the port. When a guidewire is received within port 622c and coupled to electrode 648, electrode 648 may be configured to deliver electrical energy to the guidewire in response to a user actuating button 622b. While a button is illustrated in FIGS. 7A-7C , it can be understood that any other type of actuator may be used to activate energy delivery. Similar to the slide actuator described with respect to the previous figures, actuation of the button may be configured to send a signal to the generator, triggering the generator to deliver energy to the guidewire.

[0068]

[0111] Figure 7C shows an electrosurgical device 620 including a guidewire 624 (e.g., functionally and / or structurally similar to energy delivery element 124 of Figure 1), a dilator or sheath 626 (e.g., functionally and / or structurally similar to sheath 126 of Figure 1), a dilator hub 628, and an electrosurgical interface 622. The guidewire 624 is disposed within the dilator 626 and hub 628 and may be movable relative to the dilator 626 and hub 628. A proximal end of the guidewire 624 may be received in the electrosurgical interface 622. In Figure 7C, a tip 624a of the guidewire 624 extends distally and is positioned relative to the distal end of the dilator 626 such that the guidewire 624 forms a J-shape (or other atraumatic shape). In use, the guidewire can be initially placed within the dilator 626 in a straightened configuration and then extended distally of the dilator 626 to expose the tip of the guidewire for delivering energy, e.g., for piercing tissue.

[0069]

[0112] The systems and devices described herein avoid the drawbacks of sliding contact designs, which involve physical contact between two sliding components, by using a fluid-filled chamber to establish an electrical connection between the electrosurgical generator and the electrosurgical device. The electrosurgical guidewire can be positioned within the fluid-filled chamber and freely advanced or retracted. The systems and devices described herein allow the electrosurgical guidewire to have an unconstrained proximal end, allowing the operator to freely advance, retract, or replace the guidewire without any intermediate steps, such as disconnecting a cable. In contrast to systems that may constrain the proximal end of the guidewire (e.g., clamped or clipped to a connector), the physician can quickly remove a sheath, dilator, or other instrument by retracting it over the guidewire and replace it with another instrument. This can improve workflow and potentially reduce procedure time. Furthermore, the physician or other medical professional can activate energy delivery from within a sterile environment by using an activation mechanism. Furthermore, given the frictionless (or substantially frictionless) design of the electrical connection between the generator and the electrosurgical device, the physician can rely on tactile feedback (e.g., as a result of the behavior of the guidewire tip) to assess when the guidewire is contacting a tissue surface. In the case of a transseptal puncture, this tactile feedback can be important to the physician to confirm guidewire placement, monitor when the puncture has occurred, and monitor when inadvertent contact with a tissue surface may be occurring.

[0070]

[0113] 3A-3C show various views of an example electrosurgical interface 322, according to an embodiment. Electrosurgical interface 322 can be configured to transfer electrical energy from an electrosurgical generator (e.g., generator 110, 210) to the distal tip of an electrically conductive guidewire or other energy delivery element (e.g., energy delivery element 120, guidewire 224) for therapeutic purposes, such as atrial septal puncture. Electrosurgical interface 322 can be structurally and / or functionally similar to other electrosurgical interfaces described herein (e.g., electrosurgical interfaces 122, 222).

[0071]

[0114] 3A, the electrosurgical interface 322 can include a fluid-filled chamber 344 that transfers electrosurgical energy from a cable 342 connected to a generator (not shown) to a fixed conductive electrode 348 and a movable conductive element (e.g., energy delivery element 120, guidewire 220). The fluid-filled chamber 344 can include a thin layer of conductive fluid that conducts energy from the generator and fixed electrode 348 to the movable conductive element. Thus, energy can be conducted from the generator to the distal tip of a movable conductive element, such as a guidewire.

[0072]

[0115] The chamber 344 can have a shape that makes it easy to flush and fill with fluid without any residual air bubbles remaining within the chamber 344. For example, the chamber 344 can have rounded edges or corners to avoid trapping air bubbles within the chamber. The conductive fluid used can be saline or another sterile conductive solution. In one embodiment, the conductive fluid is a 0.9% saline (NaCl) solution. The conductive fluid, combined with a large, fixed electrode surface area, can provide an electrosurgical connection that does not raise (or significantly raise) the impedance of the circuit or place an additional electrical load on the generator.

[0073]

[0116] The fixed electrode 348 may have a flat printed circuit board structure or may be a metal plate with gold, silver, steel, or copper conductors. Because the fixed electrode 348 is in contact with the patient's blood pool via the fluid pathway, the fixed electrode 348 should also be biocompatible. The fixed electrode 348 may be flat, as shown in FIGS. 3A-3C, or alternatively, may have a tubular design in which the movable conductive element is coaxial with the fixed electrode. For example, in a tubular design, the fixed electrode may be formed from a coiled wire that is coaxial with the movable conductive element.

[0074]

[0117] The movable conductive element (not shown) can be, for example, an energy delivery element or a guidewire, such as those described above with respect to FIGS. 1 and 2. In some embodiments, the movable conductive element is a metallic guidewire, with the conductive portion of the guidewire positioned adjacent to a fixed electrode surrounded by a conductive fluid. The conductive portion of the guidewire can be a stainless steel section or plated with an inert, highly conductive alloy (e.g., gold) to facilitate a low impedance path from the electrosurgical generator. In some embodiments, an insulating coating can be disposed distal or proximal to the conductive portion of the guidewire that is in the conductive fluid, for example, to provide electrical insulation along other portions of the guidewire.

[0075]

[0118] In some embodiments, an electrosurgical generator (e.g., generators 110, 210) can be integrated with an electrosurgical device (e.g., electrosurgical devices 120, 220). In such embodiments, the electrosurgical generator and device may include a handheld component, e.g., a handle assembly, that can house the generator. FIG. 10 is a schematic illustration of a handheld electrosurgical system 1000, according to an embodiment. In some embodiments, handheld electrosurgical system 1000 can include components that are structurally and / or functionally similar to other electrosurgical systems described herein, including, for example, electrosurgical system 100 of FIG. 1. Handheld electrosurgical system 1000 includes a housing 1001, which optionally includes a power source 1002 (e.g., structurally and / or functionally similar to power source 102 of FIG. 1 ), a generator 1010 (e.g., structurally and / or functionally similar to generator 110 of FIG. 1 ), and an electrosurgical interface 1022 (e.g., structurally and / or functionally similar to electrosurgical interface 122 of FIG. 1 ). Handheld electrosurgical system 1000 further includes a return electrode 1130 (e.g., structurally and / or functionally similar to return electrode 130 of FIG. 1 ) operatively coupled to generator 1010, and an energy delivery element 1024 (e.g., structurally and / or functionally similar to energy delivery element 124 of FIG. 1 ).

[0076]

[0119] The housing 1001 may be an enclosure, receptacle, or the like configured to house the power source 1002, the generator 1010, and the electrosurgical interface 1022. The housing 1001 may have a form factor that can be held in a surgeon's hand. The handheld electrosurgical system 1000 enables a less complex system due to a reduced number of separate components, thereby reducing complexity during surgery. The handheld electrosurgical system 1000 also reduces the number of supporting staff required when using the system and reduces the number of wires, cables, and / or devices on the procedure table. In some embodiments, the shape of the housing 1001 may be ergonomic for ease of use by medical professionals. In some embodiments, the housing 1001 may contain the power source 1002 (e.g., a battery, etc.). Using a battery or similar power source 1002 reduces the risk of unintended electrical energy-related problems from the power source 1002. In some embodiments, the power source 1002 is a reusable, rechargeable battery pack. In some embodiments, the housing 1001 is electrically coupled to an external power source 1002 that provides power to the electrosurgical system 1000. In some embodiments, the housing 1001 can include buttons, a display, etc. for operating the generator 1010. In some implementations, the handheld housing 1001 can be sterilized and reused.

[0077]

[0120] The energy delivery element 1024 is configured to operatively couple to the electrosurgical interface 1022. The housing 1001 can be configured to couple to an end of the energy delivery element 1024, or the energy delivery element 1024 can be configured to operatively slide through the housing 1001. The return electrode 1030 is operatively coupled to the generator 1010 and configured to couple to the patient.

[0078] Energy Delivery Element or Guidewire

[0121] Figures 8A and 8B show a guidewire 724 of an electrosurgical device (e.g., electrosurgical devices 100, 200, 400) according to one embodiment. Figure 8A provides a side view of the guidewire 724, including breaks, to better show details of the various components of the guidewire 724. Figures 8B and 8C show perspective views of the guidewire 724 within a dilator 726 forming an opening and pushing through tissue 750. The guidewire 724 may be functionally and / or structurally similar to the energy delivery element 124 of Figure 1 and / or the guidewire 424 of Figure 4.

[0079]

[0122] 8A, one embodiment of guidewire 724 includes a tip 724a, a distal curved portion 724c, a distal segment 724b, and a proximal segment 724d. Guidewire 724 is formed of stainless steel with a tapered core wire and distal coil welded at tip 724a and a proximal termination (e.g., the distal end of proximal segment 724d). Optionally, the core wire may be formed of nitinol. Guidewire 724 is formed of a biocompatible and sterile material.

[0080]

[0123] Distal segment 724b and / or proximal segment 724d conduct energy (e.g., from an electrosurgical interface) during use. Distal segment 724b may be conductive along its length and at or near its proximal end. Proximal segment 724d may have an exposed conductive region configured to electrically couple with an electrode of the electrosurgical interface (e.g., electrode 448 in FIG. 5B ). When energized, proximal segment 724d conducts this energy to the distal tip 724a of the guidewire. In some embodiments, proximal segment 724d may be partially or completely insulated to facilitate handling during use. For example, a proximal portion of proximal segment 724d may be covered with an insulating layer. The insulation may prevent current from passing through the wire and into the surgeon's hand. The insulating coating may be, for example, polytetrafluoroethylene, perfluoroalkoxyalkane, fluorinated ethylene propylene, polyimide, epoxy, ceramic, nylon, and / or a composite of insulating materials. The proximal segment 724d is rigid to facilitate large-diameter sheath exchange through tortuous patient anatomy. The distal segment 724b and / or the proximal segment 724d (or portions thereof) may have gold plating applied over the stainless steel core to improve conductivity, including thermal conductivity. Such conductivity may be beneficial, for example, for conducting heat away from the distal tip of the guidewire to prevent overheating at the distal tip. In some embodiments, the core of the guidewire 724 may be coated with tungsten or other conductive material.

[0081]

[0124] Distal segment 724b can be less rigid than proximal segment 724d. In some embodiments, distal segment 724b can include a non-conductive or insulating coating on a portion thereof, or distal segment 724b can be uninsulated. For example, as described with reference to FIG. 1, distal segment 724b can have an insulating collar surrounding a short portion of the guidewire near or adjacent the distal tip of the guidewire. In some embodiments, the distal collar can be about 2 mm to about 10 mm in length (including all subranges and values ​​therebetween). The distal end of distal segment 724b includes curved portion 724c. Curved portion 724b is formed of a shape-memory material. Curved portion 724b can be J-shaped, as in FIG. 8A, although other shapes are possible, including straight and / or other curved or spiral shapes (e.g., pigtail, coil, etc.). The J-shape of FIG. 8A is atraumatic so as not to damage the patient's anatomy while being advanced through the anatomy. Guidewire 724 is unconstrained and can remain in its J-shape as it is advanced through the patient's anatomy to the target tissue. However, to apply energy to tissue, guidewire 724 can be constrained in a straighter configuration, for example, so that distal tip 724a of the guidewire is positioned to apply energy to and pierce through the tissue. For example, when guidewire 724 is housed within a sheath or dilator (e.g., sheath 126), guidewire 724 can be constrained in a straight or substantially straight configuration. Tip 724a is a conductive and / or uninsulated portion of distal segment 724b. Tip 724 can be energized to deliver energy (e.g., RF energy) to tissue, for example, by activating electrosurgical interface 122 to transfer energy from generator 110 to an exposed region of the wire slidably positioned through electrosurgical interface 122 to create a perforation or opening. As described above, guidewire 724 can again assume a J-shape when extended beyond the perforation in the target tissue.

[0082]

[0125] 8B and 8C show the guidewire 724 in use. The guidewire 724 and sheath 126 can be advanced through the patient's vasculature to a target site. In FIG. 8B, the guidewire 724 is sheathed within a dilator 726 (e.g., functionally and / or structurally similar to the sheath 126 of FIG. 1 and / or other sheaths and dilators described herein) such that only the tip 724a protrudes from the dilator 726. In such a configuration, the tip 724a is aligned (or nearly aligned) with the longitudinal axis of the dilator 726. In some applications (e.g., when crossing a septum), as shown in FIG. 8B, the tip 724a can press against tissue 750. This can be part of tenting the tissue. Upon activation, RF energy is transmitted from the generator to the tip 724a, heating the tissue 750 at the point of contact. Heating the tissue 750 results in dehydration, protein denaturation, and loss of mechanical integrity of the tissue. The dilator 726 is then advanced to the point of contact to form a puncture hole in the tissue 750, allowing the guidewire 724 to advance into the puncture hole. Once the puncture hole is formed, energy delivery is terminated.

[0083]

[0126] In Figure 8C, a puncture hole 752 has been formed in tissue 750, and a portion of the distal segment of guidewire 724 has been advanced through puncture hole 752. As can be seen in Figure 8, the dilator may have a conical to tapered tip such that as dilator 726 is pushed further through puncture hole 752, it enlarges or expands the puncture hole. After dilator 726 is removed, a secondary treatment device (e.g., an ablation catheter, sheath, etc.) may optionally be advanced over guidewire 724 and through the enlarged puncture hole. Guidewire 724 thus acts as both an energy delivery device and a mechanism for guiding additional surgical instruments or medical devices.

[0084]

[0127] 9A and 9B show different examples of guidewires (924a and 924b) for an electrosurgical device, such as electrosurgical device 120 of FIG. 1 (e.g., structurally and / or functionally similar to energy delivery element 124 of FIG. 1 and other guidewires described herein), according to embodiments. Guidewires 924a and 924b include two segments, one of which is conductive (e.g., made of metal) and the other of which is non-conductive, at least on the outside (e.g., has an insulating coating). Different segments of guidewires 924a and 924b can have different colors, for example, to identify the guidewire as being for a specific application (e.g., one used to form a perforation) and / or to help an operator distinguish between different portions of guidewires 924a and 924b. The resulting two-color design allows for quick identification by a physician during surgery.

[0085]

[0128] Guidewires 924a and 924b include proximal segments 924d and 924f and distal segments 924c and 924e connected at transition points A and B, respectively. Distal segments 924c and 924e are made of metal or have a metal layer to provide a continuous conductor from transition points A and B, respectively, to the distal end of the guidewire (e.g., for applying electrosurgical procedures). Distal segments 924c and 924e may be gold-plated over stainless steel or another base metal, such as tungsten. The outer layer of distal segments 924c and 924e may cover manufacturing artifacts from welding, heat-setting, or molding, resulting in a smooth, uniform surface finish. Proximal segments 924d and 924f (or at least a portion thereof) are coated with an insulating coating. The coating may be PTFE, FEP, polyimide, epoxy, or nylon. The polymer may be applied by extrusion, reflow soldering, or coating. The coating can be a single uniform color, a repeating pattern, or a variety of different length segments containing different colors.

[0086]

[0129] As shown in Figures 9A and 9B, the ratio of the length of the distal segment to the length of the proximal segment may vary depending on the type of guidewire. In some embodiments, the distal segment forms at least about 20% and no more than 80% of the total length of the guidewire. In guidewire 924a of Figure 9A, distal segment 924c is longer than proximal segment 924d. In guidewire 924b of Figure 9B, proximal segment 924f is longer than distal segment 924e. In some embodiments, the lengths of the distal and proximal segments may be approximately equal.

[0087]

[0130] In one embodiment, a guidewire or other energy delivery element as described herein can be formed with multiple layers. The center of the guidewire can be a conductive core wire that can be configured to carry electrical current from the electrosurgical interface to the distal tip of the guidewire. One or more additional layers, such as coatings, coils, etc., surround the core wire. One or more conductive paths can be formed between the core wire and the outer layer of the guidewire to enable a conductive path from the outer layer to the core wire. Referring generally to FIGS. 11A and 11B, example guidewires (1124a and 1124b) are shown. The guidewires 1124a and 1124b can be coated with electrical insulators 1125a and 1125b, respectively. In some implementations, the insulators are polymers. Portions of the insulating coatings 1125a and 1125b of the guidewires 1124a and 1124b can be absent (e.g., removed using a laser or mechanical cutting instrument) to expose the conductive elements and enable electrical conductivity to the conductive elements. For example, the exposed areas may be multiple openings in the coating of guidewire 1124a, as shown in FIG. 11A, or spiral cuts in the coating of guidewire 1124b, as shown in FIG. 11B, although other cut patterns may be used. The exposed areas form one or more conductive zones to the underlying conductive elements for redundancy and to increase the path for current flow to the underlying conductive elements. In some embodiments, after a portion of the coating is exposed, the coating can be coated with a conductive coating (e.g., a metallic coating). In some embodiments, the exposed areas can be used to establish electrical communication between the core wire of the guidewire and an electrosurgical interface, such as electrosurgical interface 122 of FIG. 1.In some embodiments, the exposed region can be used to create a larger conductive surface area or active electrode area for the guidewire, which can be used to reduce the current density at the tip of the guidewire by distributing the charge or current over a larger conductive surface area of ​​the guidewire. Further details of such guidewires are described with reference to Figures 40 and 41.

[0088]

[0131] Figures 15A and 15B illustrate an unintended lesion formed by an electrosurgical device accessing the heart. As shown in Figures 15A and 15B, the illustrated heart includes an unintended lesion 1590 in the left atrium. Figure 15A shows a diagram of the lesion 1590 formed due to the guidewire of a transseptal device or other electrosurgical device 1520. The guidewire of the electrosurgical device 1520 may have contacted the wall of the left atrium after deployment from the sheath, causing the lesion 1590. The systems, devices, and methods described herein are configured to reduce the likelihood of lesions such as lesion 1590 being formed. For example, the methods described below with respect to Figures 13 and 14 can be configured to reduce the RF power of the electrosurgical device when this power is undesirable. Additionally or alternatively, the configuration and design of the guidewire or energy delivery element, as described in the following figures, can reduce the risk of lesion formation, for example, by having a lower current density as the guidewire extends distally from the dilator or outer sheath.

[0089]

[0132] In some embodiments, the guidewires or energy delivery elements of the electrosurgical systems described herein can be configured to have a low current density as they extend distally across the septum, but still maintain a high current density as they penetrate the septum. In particular, the guidewires described herein can have a longer conductive length such that as the guidewire extends across the septum into the blood pool, the longer conductive length of the guidewire spreads the current density along the length of the guidewire. This reduces the current density at any point along the guidewire, thereby reducing the risk of damage to the myocardium if the guidewire contacts the heart wall.

[0090]

[0133] For example, the guidewire can include a first distal conductive portion having a length of about 1.0 mm, a first insulating region having a length of about 0.5 mm, and a second conductive region having a length of about 12.0 cm. The first and second conductive portions can include metallic structures including coils (e.g., stainless steel coils, tungsten coils, etc.), while the insulating region can include a polymeric coating material such as polyolefin, polyethylene terephthalate, etc. The tip of the guidewire can have a current of about 25 A / cm when the first conductive region extends less than 10 mm beyond the dilator. 2 ~About 250A / cm 2 Furthermore, the conductive region of the guidewire can be configured to have a current density of 60 A / cm when the conductive region extends less than 10 mm beyond the dilator. 2 For example, the current density may be less than about 60 A / cm when the distal tip is within 0.5 mm of the sheath. 2 Furthermore, the first conductive portion and the second conductive portion may have a current of about 25 A / cm when the tip extends more than about 10 mm from the sheath. 2 It can be configured to have a current density of less than

[0091]

[0134] 16-27C, a comparison of the operation of two electrosurgical devices, Device 1 and Device 2, is shown. As shown, the two electrosurgical devices operate differently due, for example, to differences in their guidewire designs. Device 1 represents an electrosurgical device that includes an energy delivery element and a guidewire similar to the guidewire embodiments described herein, while Device 2 represents a device that includes an existing guidewire that may be used in transseptal procedures. FIGS. 16 and 17 provide more detailed details of the guidewire structure of Devices 1 and 2.

[0092]

[0135] FIG. 16 shows a cross-section of a device 1 (e.g., functionally and / or structurally similar to the electrosurgical device 120 of FIG. 1 ) including a guidewire or energy delivery element and a dilator, according to one embodiment. The energy delivery element can be functionally and / or structurally similar to other energy delivery elements or guidewires described herein, and the dilator can be functionally and / or structurally similar to other sheaths or dilators described herein. As shown in FIG. 16 , the energy delivery element includes a tip, a core, a coating (e.g., tungsten) around the core, inner and outer coils (e.g., formed of tungsten), and a gold coating on the coils and tip. The energy delivery element can include a larger active electrode area or a conductive outer surface, as described above. In use, the energy delivery device can be flushed with a fluid, such as saline. The energy delivery element can be disposed within the dilator, and a layer of blood or fluid can be disposed between the energy delivery element and the dilator.

[0093]

[0136] FIG. 17 shows a cross section of Device 2, which includes a guidewire or energy delivery element and a dilator. The energy delivery element includes a tip, a core, and a PET coating (e.g., an insulating coating) covering the conductive portion of the guidewire proximal to the tip. The energy delivery element can be disposed within the dilator, and a blood or fluid layer can be disposed between the energy delivery element and the dilator. The primary difference between the guidewire of Device 1 and the guidewire of Device 2 is the addition of an insulating coating to the guidewire of Device 2, which covers the guidewire in all areas except the tip or distal end portion of the guidewire. With this insulating coating, the only exposed conductive portion of the guidewire is the tip of the guidewire. Therefore, any energy delivered to the guidewire of Device 2 is concentrated at the tip, as reflected in the device's operation as shown in FIGS. 18-27C and 36-38B.

[0094]

[0137] Figures 16-27C and 36-38B show the operation of the guidewires of Devices 1 and 2 under simulated conditions. Using the simulated conditions, differences in the operation of the guidewires of Devices 1 and 2 are demonstrated. While some values ​​of current density, temperature, and other parameters may be shown in these figures, it can be understood that other values ​​may exist during actual, unsimulated operation of the devices. Figure 18 shows the current density and temperature of the electrosurgical devices of Figures 16 and 17 when the guidewire is being retracted into the dilator, e.g., at an insertion depth of -5 mm from the septal wall. The insertion depth reflects the distance the guidewire tips of Devices 1 and 2 are distal to the superior surface of the septum; thus, a negative insertion depth indicates that the guidewire tips of Devices 1 and 2 are proximal to the superior surface of the septum. As shown in Figure 18, Devices 1 and 2 have similar current density and thermal characteristics when positioned within the dilator (e.g., after retraction). For example, Device 1 has a maximum temperature of 44.6°C, and Device 2 has a maximum temperature of 44.3°C.

[0095]

[0138] Figure 19 shows the current density and temperature of the electrosurgical devices of Figures 16 and 17 when the guidewire extends a short distance from the dilator and engages the septum (0.5 mm insertion depth into the septal wall). As shown in Figure 19, Device 1 has a slightly lower maximum temperature than Device 2 (e.g., 99.7°C compared to 101°C), but both guidewires deliver comparable levels of energy to penetrate or puncture the septum. Furthermore, given the slightly wider geometry of the guidewire tip of Device 1 compared to the guidewire tip of Device 2, the guidewire of Device 1 generates a wider current density distribution in the septum, which may further facilitate puncture through the septum. Figure 36 shows the current density distribution of the guidewires of Devices 1 and 2, along with their maximum currents. As shown in Figure 36, the maximum current density of Device 1 is approximately 39.1 A / cm. 2 , whereas the maximum current density of Device 2 was approximately 54.6 A / cm 2 is.

[0096]

[0139] Figure 20 shows the current density and temperature of the electrosurgical devices of Figures 16 and 17 when the guidewire extends from the dilator and is at the heart wall, e.g., at an insertion depth of 21.5 mm from the septal wall. As discussed above, insertion depth reflects the distance the tip of the guidewire for Device 1 and Device 2 is distal to the proximal surface of the septum. As shown in Figure 20, the current for Device 1 is more distributed over its exposed length compared to Device 2. As such, the current density at the heart wall for Device 1 is significantly lower than the current density at the heart wall for Device 2. This is illustrated in Figure 37, which shows that the guidewire for Device 1 has a current density of 8.45 A / cm at the heart wall. 2 and the guide wire of device 2 had a maximum current density of 55.5 A / cm 220 shows that Device 1 has a maximum current density of 39.8°C. The lower current density at the heart wall for Device 1 is due to Device 1 having a longer exposed conductive length, which acts to spread or dissipate the energy being delivered to the tip of the guidewire. In comparison, Device 2 includes conductive portions only at its tip due to its insulating coating, thus concentrating the current density at its tip. The lower current density indicates that Device 1 is less likely to cause undesired tissue damage than Device 2. Furthermore, the temperature at its tip of Device 1 is significantly lower than that of Device 2. Specifically, the simulation results in FIG. 20 show that Device 1 had a maximum temperature of 39.8°C and Device 2 had a maximum temperature of 98.5°C. Therefore, a user of Device 1 is less likely to damage the heart wall than a user of Device 2. The lower temperature for Device 1 may be due to heat absorption or dissipation over the longer length of the device compared to Device 2. As previously described with respect to FIG. 16, Device 1 may include a gold coating that can be configured to conduct heat away from the distal tip of the device. As such, the temperature at the tip of device 1 is lower and, therefore, device 1 is also less likely to cause unintended damage or interrogation of tissue surfaces, including, for example, the heart wall. Although gold is provided as an example of a material capable of conducting heat away from the tip of device 1, it can be understood that any other type of heat conductor can be used as a coating, layer, or other component of device 1 (or any of the other energy delivery elements or guidewires described herein) to reduce heat at the tip of device 1. For example, a material such as diamond (e.g., applied using chemical vapor deposition (CVD)) can be applied to one or more components of the energy delivery elements / guidewires described herein to provide electrical insulation and / or reduce the temperature at the tip of such component.

[0097]

[0140] The phenomenon of current density distribution can be further seen in Figure 21, which shows the current density and temperature of the electrosurgical devices of Figures 16 and 17 when the guidewire extends from the dilator and is positioned in the blood pool (e.g., the left atrium). As shown in Figure 21, the current density generated by Device 1 is distributed along the length of the guidewire, while the current density generated by Device 2 is concentrated around the tip of the guidewire. As discussed above, this concentration can be problematic because it can cause damage, such as the damage shown in Figures 15A and 15B, if the guidewire tip comes into contact with the heart wall. The distributed current density and lower current density value generated by Device 1 makes it less likely to cause damage because the current density is distributed along the length of the guidewire. Figure 37 shows that the guidewire of Device 1 generates 8.14 A / cm in the blood pool. 2 and the guide wire of Device 2 had a maximum current density of 44.5 A / cm in the blood pool. 2 Furthermore, the temperature at its tip of Device 1 is lower than that of Device 2. Specifically, the simulation results in FIG. 21 show that the maximum temperature of Device 1 is 37.5°C and the maximum temperature of Device 2 is 42.5°C. While being in the blood pool helps to dissipate heat buildup at the tips of both Devices 1 and 2, the additional gold coating on Device 1, which can help draw heat away from the tip, further helps draw heat away from the tip of Device 1.

[0098]

[0141] 37, both at the heart wall and within the blood pool, the maximum current density of Device 1 is substantially less than the maximum current density of Device 2. As noted above, this difference is due to Device 1 being able to dissipate the current along the length of the guidewire rather than concentrating it at the tip of the guidewire as Device 2 does.

[0099]

[0142] 38A and 38B plot the maximum current density of the guidewires of Devices 1 and 2 when the guidewire is placed against the septum (ID=0.5, with myocardium), inserted through the septum and placed in the blood pool (ID=21.5, without myocardium), and placed against the heart wall (ID=21.5, with myocardium). Again, as shown in these plots, Devices 1 and 2 can have sufficiently high maximum current densities at the septum to allow them to puncture the septum, while Device 1 has a significantly lower maximum current density after penetrating the septum compared to Device 2. The lower current density at the heart wall and in the blood pool reduces the likelihood of accidental lesion formation.

[0100]

[0143] FIG. 22 shows the temperature of the septum and the tip of the guidewire as a function of time for Devices 1 and 2 at an insertion depth of 0.5 mm, i.e., when the tip engages the septal wall. As shown in FIG. 22, the temperature at the septum from Devices 1 and 2 is approximately 100°C. However, the tip temperature of Device 1 is lower than that of Device 2, indicating that the guidewire of Device 1 dissipates heat more effectively than the guidewire of Device 2. As shown in FIG. 16, the guidewire of Device 1 may include gold plating. Gold is an effective thermal conductor and therefore may contribute to the dissipation or wicking of heat from the tip of the guidewire. While gold is provided as an example of an effective thermal conductor, other thermally conductive materials, such as diamond, other metals, etc., may also be used.

[0101]

[0144] 23A-23C show graphs of the terminal voltage, terminal current, and terminal impedance, respectively, for the electrosurgical devices of FIGS. 16 and 17 when the guidewire is at an insertion depth of 0.5 mm in the septum. As shown in FIGS. 23A-23C, Device 1, when energized, has a lower terminal voltage, a higher terminal current, and a lower terminal impedance than Device 2. While there is a difference in terminal voltage between Device 1 and Device 2, the difference is not significant at an insertion depth of 0.5 mm, allowing Device 1 to also be effective at penetrating tissue.

[0102]

[0145] 24A and 24B show graphs of temperature as a function of time for the electrosurgical devices of FIGS. 16 and 17 when the guidewire is inserted through the septum to an insertion depth of 21.1 mm and is either at the heart wall (with myocardium) or within the blood pool (without myocardium). As discussed above, insertion depth reflects the distance the guidewires of Devices 1 and 2 are inserted beyond the upper surface of the septum. FIG. 24A shows the temperatures at the myocardium and the guidewire tips of Devices 1 and 2 when they are in contact with the myocardium. As shown in FIG. 24A, the temperatures of the myocardium and guidewire tip of Device 1 are lower than those of Device 2. The lower temperatures again reflect that Device 1 is better configured to dissipate heat. Therefore, Device 1 is less likely to cause damage to the myocardium than Device 2. The heat dissipation effect of Device 1 can also be seen in FIG. 24B, which shows the temperature of the blood pool and the tip of the guidewire within the blood pool. As shown in FIG. 24B, the temperature of both the guidewire tip and the blood pool was higher for Device 2 than for Device 1, indicating that Device 1 was better able to dissipate heat.

[0103]

[0146] Figures 25A-25C show graphs of terminal voltage for the electrosurgical device of Figures 16 and 17 when the guidewire is inserted through the septum to a depth of 21.1 mm and is either at the heart wall (with myocardium) or in the blood pool (without myocardium). Figures 26A-26C show graphs of terminal current for the electrosurgical device of Figures 16 and 17 when the guidewire is inserted through the septum to a depth of 21.1 mm and is either at the heart wall (with myocardium) or in the blood pool (without myocardium). Figures 27A-27C show graphs of terminal impedance for the electrosurgical device of Figures 16 and 17 when the guidewire is inserted through the septum to a depth of 21.1 mm and is either at the heart wall (with myocardium) or in the blood pool (without myocardium). As shown in these figures, the terminal voltage at the tip of the guidewire of Device 1 is significantly lower than that of Device 2 and is therefore less likely to cause damage or injury to the myocardium or other tissue surface. The impedance of the guidewire of Device 1 also remains generally lower than the impedance of the guidewire of Device 2 because more of the conductive area of ​​the guidewire is exposed, allowing charge to dissipate along a longer length of the guidewire.

[0104]

[0147] In some embodiments, systems, devices, and methods can be configured to monitor the impedance of a guidewire or energy delivery element according to embodiments disclosed herein. As shown in FIGS. 23C and 27A-27C, the impedance of the guidewire decreases when the guidewire is placed in the blood pool or against the myocardium (wall of the heart). This decrease in impedance is due to the increased exposed conductive surface area of ​​the guidewire. Therefore, monitoring the decrease in impedance (e.g., using a controller such as processor 114, as described above) can enable the system to adjust the voltage being delivered, for example, to avoid high current values ​​and thereby current leakage.

[0105]

[0148] In some embodiments, the electrosurgical devices described herein can include a guidewire with an insulating collar. Figures 28A and 28B show cross-sectional views of an example guidewire 2924 (e.g., functionally and / or structurally similar to energy delivery element 124 of Figure 1) having a tip 2924a with an insulating collar 2924e, according to an embodiment. Guidewire 2924 includes tip 2924a, a coil 2924b, an insulating collar 2924e, a fluid 2924f, and a core 2924g. In this embodiment, guidewire 2924 is symmetrical about a central axis, with the proximal side of coil 2924b coated with an insulating coating.

[0106]

[0149] Tip 2924a is electrically coupled to core 2924g, which is operatively connected to a generator, optionally via an electrosurgical interface, such as electrosurgical interface 122 of FIG. 1. Core 2924g transmits energy to tip 2924a, thereby enabling tip 2924a to engage and deliver energy to tissue. Tip 2924a defines tip width 2924c and tip length D3. In some embodiments, length D3 can be about 0.5 to about 2 mm (including all subranges and values ​​therebetween). In some embodiments, tip width 2924c is configured to fit within a sheath, such as sheath 126 of FIG. 1, and to deliver a desired amount of energy to tissue. Proximal to tip 2924a, core 2924g is surrounded by fluid 2924F. As shown in FIG. 28B, fluid 2924f can include saline. During surgery, the fluid may include a mixture of blood and saline. Fluid 2924f is surrounded by coil 2924b. In some embodiments, coil 2924b is formed of stainless steel. Additionally, as shown in FIG. 28B, tip 2924a of coil 2924b may be coated with a conductive coating. In some embodiments, the conductive coating may include gold, tungsten, tantalum, or the like.

[0107]

[0150] In some embodiments, a portion of coil 2924b is covered with insulating collar 2924e. Insulating collar 2924e is flush with the remaining portion of coil 2924b. Insulating collar 2924e can be made flush with coil 2924b by compressing and / or stretching coil 2924b, for example, by being placed over the stretched portion of coil 2924b. Insulating collar 2924e can begin along coil 2924b at a length D1 from the distal end of guidewire 2924. In some embodiments, length D1 can be about 0.5 mm to about 3 mm (e.g., about 1 mm to about 2 mm, including all subranges and values ​​therebetween) from the distal end of the guidewire. Insulating collar 2924e has a length D2. In some embodiments, length D2 can be about 2 mm to about 10 mm (e.g., about 4 mm to about 6 mm, including all subranges and values ​​therebetween). Collar 2924e can have a length that allows the current density at the distal end of the guidewire to remain high for the short distance (e.g., less than about 10 mm) necessary to ensure penetration into the septum, but is not so long that the current density at the distal end drops as the guidewire is inserted beyond the septum and into the blood pool in the left atrium. In some embodiments, insulating collar 2924e is formed from a polymer, ceramic, or thermoplastic (e.g., PEBAC, Grilamid, PET, PTFE, FEP, PEEK, etc.). In some embodiments, insulating collar 2924e may be applied via chemical vapor deposition (CVD). For example, CVD can be used to apply a diamond layer onto coil 2924b to form insulating collar 2924e. In some embodiments, insulating collar 2924e is configured to reinforce the distal end of guidewire 2924. In some embodiments, guidewire 2924 is sufficient to provide a penetration force of about 0.1 to 5 Newtons. Insulating collar 2924e defines a thickness Ti. Optionally, thickness Ti may be constant throughout the portion of coil 2924b covered by insulating collar 2924e.In some embodiments, the thickness Ti is greater than a predetermined minimum thickness corresponding to the thickness necessary to prevent dielectric breakdown. In some embodiments, the insulating collar can have a thickness desired to provide a predetermined stiffness or flexibility of the guidewire 2924.

[0108]

[0151] Figure 29 shows an electrosurgical device (Device 3) engaging the septum, according to an embodiment. Device 3 includes an insulating collar (e.g., a 5 mm long PET collar) formed of insulating material disposed on a portion of the device's guidewire near its distal tip. The electrosurgical device of Figure 29 may otherwise be similar to the electrosurgical device of Figure 16. For example, the electrosurgical device of Figure 29 may include a tip, a core, inner and outer coils (e.g., formed of tungsten), and a gold coating. In use, the energy delivery device can be flushed with a fluid, such as saline.

[0109]

[0152] Device 1 and Device 3, as shown in FIG. 16 , are both examples of energy delivery elements or guidewires described herein and, therefore, may be structurally and / or functionally similar to other energy delivery elements or guidewires described herein. While Device 3 can operate similarly to Device 1 under most conditions, due to the addition of an insulating collar, Device 3 may exhibit different operational behavior compared to Device 1 when the guidewires of the two devices extend a short distance from the dilator. In particular, the guidewires of Devices 1 and 3 may operate similarly to each other when each extends less than about 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, or 0.5 mm (including any subrange or value therebetween) from the dilator. When extending these minimum distances from the dilator, the exposed conductive surface area of ​​each guidewire may be small, and the current density of each device at the tip of the guidewire may be high and sufficient to penetrate and puncture tissue (e.g., the septum). However, as the guidewires extend further from the dilator, the two devices may exhibit different behavior. In some embodiments, it may be desirable or necessary to extend the guidewire a greater distance from the sheath or dilator (e.g., when the dilator-tissue contact is not perpendicular). Device 1, without an insulating collar, has a conductive surface area that increases as it extends beyond the dilator compared to Device 3, with an insulating collar. As a result, the current density of Device 1 may be reduced relative to that of Device 3 at these initial short distances (e.g., less than about 10 mm, about 9 mm, about 8 mm, about 7 mm, about 6 mm, about 5 mm, about 4 mm, about 3 mm, or about 2 mm, including all subranges and values ​​therebetween). Thus, for distances of about 1 mm to about 10 mm, the insulating collar can help maintain the current density at the guidewire tip of Device 3 at higher displacement values, thereby allowing Device 3 to continue to deliver sufficient energy to penetrate and puncture tissue (e.g., a septum). The following figures demonstrate the differences between Device 1 and Device 3.

[0110]

[0153] FIGS. 30A-30C and 39-41B provide a comparison of the behavior of Device 1 and Device 3 under simulated conditions. Using the simulated conditions, the differences in guidewire behavior between Device 1 and Device 3 are demonstrated. FIG. 30A shows the behavior of the two devices when the guidewire is in the septum and extends a short distance (e.g., about 0.4 inches or about 10 mm) from the dilator. For illustrative purposes, the short distance that the two guidewires extend from the dilator is intentionally set to fully expose the collar along with one or more conductive portions of the guidewire. FIG. 30B shows the behavior of the two devices when the guidewire is in the heart wall and extends a longer distance from the dilator compared to FIG. 30A. Additionally, FIG. 30C shows the behavior of the two devices when the guidewire is in the blood pool and also extends a longer distance from the dilator compared to FIG. 30A.

[0111]

[0154] As shown in FIG. 30A, when the guidewire of Device 1 extends approximately 10 mm from the dilator, the current density is distributed throughout the length of the guidewire, and thus the energy at the tip drops to a lower value. In contrast, when the guidewire of Device 3 extends approximately 10 mm from the dilator (e.g., enough to expose the insulating collar), it has a higher current density at the tip due to the insulating collar. The insulating collar prevents current from dissipating in the portion of the guidewire it covers, thus reducing the drop in current density at the tip as the guidewire extends from the dilator. This can help prevent the guidewire from losing excessive energy at its tip as it extends from the dilator, at least for a short distance. Thus, the tip of the guidewire can be effective at penetrating the septum until it extends a certain distance from the dilator. This distance can be less than approximately 10 mm, less than approximately 15 mm, or less than approximately 20 mm (including all subranges and values ​​therebetween). This allows Device 3 to be configured to penetrate the septum over a wider range of guidewire extension distances. After penetrating the septum, the higher current density of Device 3 is similarly reduced, thereby reducing the likelihood of accidental lesion formation. As a result of the collar, Device 3's maximum temperature (60.8°C) is slightly higher than Device 1's maximum temperature (50.9°C), but this temperature increase does not affect the device's operation. The temperatures of both guidewires remain below those that would lead to undesirable results, such as agglomeration or charring.

[0112]

[0155] As shown in Figures 30B and 30C, when the guidewire of Device 3 extends further from the dilator, e.g., at the heart wall or in the blood pool beyond the septum, the current density at the tip of the guidewire also decreases, similar to that of Device 1. In other words, as the guidewire of Device 3 extends further from the dilator, the conductive surface area of ​​the guidewire increases sufficiently so that the current density of the guidewire at the tip decreases to a level unlikely to cause damage to the heart wall. Thus, Devices 1 and 3 behave similarly to each other when their guidewires extend beyond the septum, exposing their longer conductive surface areas. As shown in Figures 30B and 30C, the temperature profiles of the two guidewires may be similar at the heart wall or within the blood pool. Notably, the maximum temperature of Device 1 is 39.8°C at the heart wall, and the maximum temperature of Device 3 is 41.5°C at the heart wall. The maximum temperature for Device 1 is 37.4°C in the blood pool, and the maximum temperature for Device 3 is 37.4°C in the blood pool. As shown in Figure 39, the maximum current density for Device 3 also decreases, but remains higher than that of Device 1. At the heart wall, the maximum current density for Device 1 is 3.52 A / cm 2 and the maximum current density of Device 3 was 49.8 A / cm 2 In the blood pool, the maximum current density of Device 1 is 3.40 A / cm 2 and the maximum current density of Device 3 was 61.1 A / cm 2 is.

[0113]

[0156] 31A-33, various embodiments for positioning insulating collars and the like are shown. The insulating collars may be functionally similar to the insulating collars of Figures 28A-29 or may be used to form insulating collars similar to the insulating collars of Figures 28A-29. The insulating collars of Figures 31A-33 may be used, for example, with a guidewire, such as the energy delivery element of Figure 1 or any other guidewire described herein.

[0114]

[0157] FIG. 31A shows an example of forming an insulating collar by first adding an insulating region 3224b to a coil wire 3224a. After the insulating region 3224b is placed on the coil wire 3224a, the coil wire 3224a can be wrapped around a guidewire core or around a mandrel to form a coil. The formation of the coil can be seen in FIG. 31B, where the coil wire 3224a is wrapped around a mandrel 3224c to form the coil. The coil can then be placed over the guidewire core and welded to it. The resulting insulating region can serve as the insulating collar of the guidewire, as shown in FIG. 31B. FIG. 32 shows an example of an insulating collar 3324b on a guidewire 3324, according to an embodiment. The insulating collar 3324b in FIG. 32 is a solid portion (e.g., a solid ring) adjacent the tip 3324a of the guidewire 3324. Insulating collar 3324b can be disposed over guidewire core 3324d, which is coupled to tip 3324a. Insulating collar 3324b can be coupled at its proximal end to coil 3324c. In some embodiments, coil 324c is welded, glued, etc. to insulating collar 3324b. FIG. 33 shows an example of an insulating collar implemented as coil 3424b on guidewire 3424, according to an embodiment. Coil 3424b can be a coil formed of an insulating or low-conductivity material wrapped around core 3424d. Coil 3424b is located between conductive coil 3424c and tip 3424a, providing guidewire 3424 with an insulating portion proximal to tip 3424a.

[0115]

[0158] FIG. 34 shows another example of a guidewire 3524 with an insulating collar 3524c, according to embodiments. The guidewire 3524 can be structurally and / or functionally similar to other energy delivery elements and / or guidewires described herein. The insulating collar 3524c can have a length of about 1 mm to about 20 mm, including all values ​​and subranges therebetween. As discussed above with respect to FIG. 28A, it may be desirable for the insulating collar of the guidewire to be flush (or substantially flush) with the outer surface of the guidewire. This can ensure that the surface of the guidewire is free of any edges or features that could unintentionally snag or engage other structures. In some embodiments, to provide a flush outer surface of the guidewire, the collar may be positioned over a section of the guidewire where there is a gradual decrease in the thickness of the core wire (or other internal component). For example, as shown in FIG. 34, the collar 3524b may be positioned over a region of the guidewire where the core wire 3524c has a smaller diameter. Optionally, this region may also have a coil 3524d disposed over the core wire, which may also be compressible to further allow the collar to be disposed flush with the outer surface of the guidewire. The guidewire, like other guidewires described herein, may also include a tip 3524a.

[0116]

[0159] In some embodiments, a guidewire as described herein includes a thermally conductive portion. As discussed above, using an RF-powered guidewire or needle to create an atrial-septal defect, for example, for transseptal access, can pose a thromboembolic risk by inadvertently creating char and / or clots. Char and clots can form when tissue temperatures exceed a threshold that triggers protein denaturation, dehydration, and / or the thrombosis cascade. Therefore, maintaining the temperature of the guidewire tip below a predefined threshold can prevent or reduce the risk of char and clot formation, thereby avoiding thromboembolic risks to the patient.

[0117]

[0160] FIG. 35 shows a schematic diagram of implementing temperature control using the energy delivery elements and guidewires described herein, according to an embodiment. As shown, a generator 3610 (e.g., structurally and / or functionally similar to other generators described herein) is coupled to an energy delivery device 3622. A physician can activate an actuation device (e.g., structurally and / or functionally similar to other actuators or actuation devices described herein) to deliver RF power to the energy delivery element 3622. The energy delivery element 3622 can be structurally and / or functionally similar to other energy delivery elements and / or guidewires described herein. In one embodiment, the energy delivery element 3622 can be a guidewire. For example, to monitor the temperature of the tissue contact area, one or more temperature sensors (e.g., thermistors, thermocouples, etc.) can be coupled to or incorporated into the energy delivery device near the expected tissue contact area. The temperature sensor signal can then be sent to the generator 3610, which can be configured to modulate or control the RF power based on the temperature feedback. In some embodiments, the generator 3610 can be configured to deliver RF power to reach a target setpoint temperature or range. The target setpoint temperature or range can be from about 55 degrees Celsius to about 80 degrees Celsius, including all values ​​and subranges therebetween. Avoiding temperatures above 80 degrees Celsius can reduce the occurrence of char and agglomeration.

[0118]

[0161] In some embodiments, the guidewire can include a thermally conductive material that can be configured to wick or draw heat away from the tip of the guidewire. Existing guidewires can include irrigated guidewires that can directly cool the electrode and nearby tissue. However, in some cases, coagulum can still form on the electrode of an irrigated guidewire, particularly near the boundary between the electrode and the polymer insulation proximal to the tip, where heat from the tip can be trapped by poor heat transfer in the polymer. Currently, existing guidelines for transseptal access do not include irrigation. An energy delivery device or guidewire as described herein can provide cooling via a larger tip electrode. This is because a longer, uninsulated active electrode area (e.g., greater than about 1 cm, 2 cm, etc.) can wick or draw heat away from the tip of the guidewire, in contrast to other guidewires that may include plastic or insulating materials that prevent heat transfer. However, as discussed above, it may be desirable to maintain RF current density over various use conditions (e.g., when the dilator-tissue contact is not perpendicular) by covering some portions of the active electrode with electrical insulation. In such embodiments, an insulating collar may be used to cover a portion of the active electrode or the conductive outer surface of the guidewire, as described, for example, with reference to Figures 29-34 and 40-42C. The collar may be formed of a thermally conductive material so that it does not impede or reduce heat transfer away from the tip and increase the risk of char or agglomeration.

[0119]

[0162] 40 shows a tip of a guidewire 4224 including a thermally conductive portion, according to an embodiment. The guidewire 4224 can be structurally and / or functionally similar to other guidewires described herein, including, for example, the energy delivery element 124 of FIG. 1. For example, the guidewire 4224 can include a tip 4224a, a thermally conductive portion 4224b, an electrically conductive portion 4224d, and a standard insulating portion 4224e.

[0120]

[0163] Tip 4224a is formed of a solid metal (e.g., stainless steel, etc.) configured to deliver energy for puncturing through the septum. Tip 4224a can have a length of about 0.1 mm to about 1 mm (e.g., about 0.5 mm, including all values ​​and subranges therebetween). In some embodiments, tip 4224a can be an electrically conductive portion having a length of about 0.25 mm to 30 cm. Thermally conductive portion 4224b can be adjacent to and proximal to tip 4224a. In some embodiments, thermally conductive portion 4224b can be implemented as an electrically insulating collar, similar to other insulating collars described herein (e.g., collar / PET coating, collar 3524b of device 3). The location of thermally conductive but electrically insulating portion 4224b can allow current density to be concentrated at tip 4224a. Thermally conductive portion 4224b can be formed of a thermally conductive polymer or metal (e.g., tungsten, tantalum, platinum, gold, etc.). In some embodiments, thermally conductive portion 4224b can be configured to provide heat transfer and electrical insulation so as to avoid increasing the outer conductive surface area of ​​the guidewire. Therefore, materials such as platinum and gold, which increase the conductive surface area of ​​the electrode, may be undesirable. In some embodiments, thermally conductive portion 4224b (e.g., or electrically insulating region) can be about 2 mm to about 2 cm in length.

[0121]

[0164] In some embodiments, the guidewire 4224 can optionally include a marker band 4224c. In such embodiments, the marker band 4224c can be adjacent to and proximal to the tip 4224a. The marker band 4224c can be implemented as a coating on the thermally conductive portion 4224b. Alternatively, the marker band 4224c can be a separate element or component from the thermally conductive portion 4224b. The marker band 4224c is formed of a material that allows the marker band 4224c to be visible during imaging, for example, a radiopaque material that is visible under fluoroscopy. The marker band 4224c can be formed of a thermally conductive material, for example, to allow heat transfer from the tip 4224a. In some embodiments, the marker band 4224c can be implemented with a diamond coating that allows heat to be dissipated while being an electrical insulator. The diamond coating may be disposed on a band made of a radiopaque material such as platinum, tantalum, or tungsten.

[0122]

[0165] Conductive portion 4224d is proximal to thermally conductive portion 4224b. Conductive portion 4224d can include a conductive outer surface. In some embodiments, conductive portion 4224d can include one or more features (e.g., notches, holes, slots) that enable conductive portion 4224d to have a conductive outer surface. For example, conductive portion 4224d can include features such as those described with reference to FIGS. 11A and 11B. Alternatively, or in addition, conductive portion 4224d can include a conductive polymer coating. Conductive portion 4224d can enable current to be distributed along a portion of the length of guidewire 4224, for example, by providing a larger active electrode area. Standard portion 4224e is formed of an electrically insulating material (e.g., a polymer) configured to insulate and protect guidewire 4224. In some embodiments, conductive portion 4224d is about 5 mm to about 30 cm in length.

[0123]

[0166] The configuration of guidewire 4224 allows for a lower operating power for guidewire 4224 than known systems because marker band 4224a and thermally conductive portion 4224b allow current density to be concentrated at tip 4224a during operation, and conductive portion 4224d allows current density to dissipate along the length of guidewire 4224 after tip 4224a engages and pierces the septum and conductive portion 4224d is exposed. In some embodiments, the operating power is from about 10 watts to about 40 watts (including all subranges and values ​​therebetween). In some embodiments, the operating power is from about 10 watts to about 25 watts.

[0124]

[0167] FIG. 41 shows a cross-sectional view of a guidewire 4224, according to one embodiment. As shown in FIG. 41, the inside of the guidewire 4224 includes a core 4224f, an inner coil 4224g surrounding the core 4224f, and an outer coil 4224h surrounding the inner coil 4224g. The core 4224f contacts (e.g., is glued to) the tip 4224a. The inner coil 4224g wraps around the core and terminates at the tip 4224a. The outer coil extends along the guidewire 4224 to a marker band 4224b. The inner and outer coils can provide support while allowing flexibility of the guidewire. In some embodiments, the outer coil 4224h is coated. In some embodiments, the coating is a polymer. In some embodiments, the coating is gold, for example, for heat transfer. In some embodiments, the diameter or size of the wire used to form the outer coil 4224h is larger than the diameter or size of the wire used to form the inner coil 4224g.

[0125]

[0168] 42A-42C illustrate yet another example of a guidewire 4424, according to embodiments. The guidewire 4424 can be structurally and / or functionally similar to other energy delivery elements or guidewires described herein, including, for example, energy delivery element 124, guidewires 624, 724, 924, 4224, etc. Accordingly, the guidewire 4424 can include components similar to those of other guidewires described herein. For example, the guidewire 4424 can include a tip 4424a, a collar 4424b, and a conductive portion 4424d. The guidewire 4424 is configured to be disposed within a dilator or sheath 4426, which can be functionally and / or structurally similar to other dilators and / or sheaths described herein (e.g., sheath 126, 426, 626, 726, etc.).

[0126]

[0169] FIG. 42A shows a guidewire extending a short distance from the outer sheath or dilator 4426. For example, the guidewire can extend a distance of about 0.5 mm to about 15 mm, including all values ​​and subranges therebetween. For example, as described above with reference to FIG. 8B, the guidewire can be extended a short distance from the dilator 4426 to expose the conductive tip 4424a of the guidewire. The conductive tip 4424a can then be used to deliver energy to perforate tissue. When extended these short distances from the dilator 4426, the guidewire has a small exposed conductive surface area. This small conductive surface area can allow current density to be concentrated at the tip 4424a of the guidewire, thereby enabling the tip to generate enough energy to perforate a tissue wall, such as a septum. As described above, in some embodiments, the guidewire can have a collar 4424b, which can be formed of an insulating material or a material having low electrical conductivity. A collar 4424b can be positioned adjacent the guidewire tip 4424a so that the conductive surface area of ​​the guidewire exposed beyond the dilator 4426 does not increase or remains the same (or substantially the same) as the guidewire extends these short distances outside the dilator 4426. This can ensure that the current density at the guidewire tip remains high enough to perforate tissue of a certain thickness (e.g., about 0.1 mm to about 15 mm). As mentioned above, in some embodiments, the collar 4424b can also be formed of a thermally conductive material, such as gold. This can, for example, allow heat to be drawn away from the guidewire tip to avoid undesirable effects, as discussed above.

[0127]

[0170] As shown in FIG. 42B, the guidewire can be extended a further distance beyond the distal end of the dilator 4426. As described above with reference to FIG. 8C, after the guidewire penetrates and punctures or pierces the target tissue (e.g., the septum), the guidewire can be extended beyond the tissue. In some embodiments, the guidewire can be used as a delivery catheter for additional instruments. For example, the guidewire can be used to perform a transseptal crossing and then used to guide additional instruments (e.g., electrosurgical or therapeutic devices, catheters, etc.) into the left atrium of the heart. As shown in FIG. 42B, when the guidewire is extended this greater distance, the guidewire can be configured to assume an atraumatic shape, such as, for example, a J-shape, a pigtail shape, etc. The atraumatic shape can be configured to reduce damage to nearby tissue structures. When the guidewire is extended this greater distance, a distal conductive surface or portion 4424b of the guidewire is also exposed. This distal conductive portion 4424b can be an exposed surface of a metal coil or other conductive material. The coil can be electrically coupled to the core 4424c of the guidewire, as shown in FIG. 42C. Thus, energy delivered to the tip can be distributed across the tip and the additional exposed conductive surface 4424d. As discussed above, this increased conductive surface area reduces current density, thus further preventing and / or reducing potential damage to nearby tissue structures. For example, as discussed above, when used in a transseptal crossing procedure, the increased exposed conductive surface area of ​​the guidewire can reduce the likelihood of injury to the heart wall.

[0128]

[0171] 42B and 42C, additional conductive surface 4424d is shown as the exposed surface of a coil, it will be appreciated that other conductive surfaces may be used to increase the overall conductive surface area of ​​the guidewire. For example, as described with reference to FIGS. 11 and 11B and 40 and 41, conductive surface 4424d may be formed from an insulating coating that has cutouts or patterns formed therein that expose the underlying conductive elements.

[0129]

[0172] Figure 42C provides a detailed cross-sectional view of the guidewire 4424. As shown in Figure 42C, the core 4424c of the guidewire extends throughout its length. In some embodiments, the core 4424c can have a proximal section with a larger diameter than the distal section. At or near the proximal end of the guidewire, the core 4424c can be exposed and in electrical communication with a generator (e.g., via any of the electrosurgical interfaces described herein, e.g., electrosurgical interfaces 122, 222, 322, 422, 522, 622, etc.). Alternatively, in some embodiments, the core 4424c can be covered by an insulating material but include one or more openings (e.g., holes, slots, or other notches) that allow for the transmission of electrical current to the core 4424c, such as those described with reference to Figures 11A and 11B above. Core 4424c can then be covered by an insulating coating or layer 4424e, such as a polymer, etc. Insulating layer 4424e can cover core 4424c up to the distal segment of the guidewire, which can be about 10 to about 100 cm in length, including all values ​​and subranges therebetween.

[0130]

[0173] The guidewire can begin at or near the beginning of the distal segment of the guidewire and transition from being covered by an insulating layer 4424e to having an external conductive coil 4424d. The conductive coil 4424d can be formed of a conductive material, such as a metal or metal alloy, as described above. The coil 4424d can then extend distally from the distal end of the insulating layer 4424e to the tip 4424a of the guidewire. As described above, the coil 4424d can be coupled to the distal tip 4424a so that the coil 4424d, together with the tip 4424a, can form a long electrode or conductor. When the coil 4424d, together with the tip 4424a, is exposed, for example, beyond the distal end of the dilator, the coil 4424d and the tip 4424a can provide a larger surface area over which energy or current delivered to the guidewire can be spread, for example, to reduce current density at the tip 4424a. As shown in FIG. 42C , the core 4424c can be tapered along its length in the distal segment of the guidewire, for example, to provide greater flexibility near the distal end of the guidewire. A collar 4424b can be positioned near or adjacent the tip 4424a of the guidewire. In some embodiments, the collar 4424b can be positioned over the coil 4424d. In such embodiments, the coil 4424d can have a smaller outer diameter than other regions such that the outer diameter of the guidewire in the region of the collar 4424b remains constant. In other embodiments, the guidewire 4424b can have a slightly larger diameter in the region of the collar 4424b.

[0131] method

[0174] FIG. 12 is a flowchart of a method 1200 of using the systems and devices described herein, according to an embodiment. Method 1200 includes, at 1202, advancing a guidewire (e.g., functionally and / or structurally similar to energy delivery element 124 of FIG. 1 or other guidewires described herein) through the vasculature to the patient's right atrium (or other anatomical structure), optionally configuring the guidewire for perforation at 1204 (e.g., by advancing a sheath over the guidewire to straighten the guidewire), positioning a distal end of the guidewire against tissue (e.g., the septum) at 1206, activating energy delivery to perforate the tissue at 1208, advancing the guidewire through the perforation at 1210, advancing a dilator over the guidewire to dilate the perforation at 1212, and optionally advancing a medical device (e.g., a catheter) over the guidewire to a target site for treatment at 1214.

[0132]

[0175] At 1202, a guidewire is advanced to a target location within the patient. The target location may be the right atrium of the heart or other patient anatomy (e.g., the heart, vasculature, or other anatomy). In some embodiments, the guidewire is inserted into the femoral vein through a puncture made by standard needle puncture techniques. The guidewire is advanced or advanced through the vasculature using fluoroscopy and / or ultrasound imaging. The guidewire can be advanced through the vasculature and positioned above the right atrial chamber in the superior vena cava (SVC).

[0133]

[0176] Before or after advancing the guidewire into the right atrium (or other anatomical structure), the guidewire can be connected to a generator, for example, via an electrosurgical interface (e.g., electrosurgical interface 122, 222, etc.). To connect the guidewire to receive energy from the generator, an intervascular sheath and / or dilator (e.g., sheath 126, dilator 426, etc.) can be prepared by attaching the electrosurgical interface to the lumen of the sheath via a standard Luer connection. In some embodiments, the fluid lumen is flushed with sterile 0.9% sodium chloride saline to remove air within the lumen. The sheath is then loaded onto the proximal end of the guidewire and advanced into the patient's vasculature so that the distal tip of the dilator is positioned within the right atrium.

[0134]

[0177] In some embodiments, as described above, the guidewire can have a J-shape or other atraumatic distal end shape. In such embodiments, the guidewire may first need to be configured for drilling (e.g., a straightened or substantially straightened configuration) at 1204 before it can be used to penetrate and drill tissue. Thus, at 1204, the guidewire is optionally configured for drilling (e.g., a straightened or substantially straightened configuration). In some embodiments, configuring the guidewire for drilling includes advancing a sheath, as described above, over the distal curved portion of the guidewire to straighten the guidewire. In some embodiments, configuring the guidewire for drilling includes retracting the guidewire into the sheath so that the guidewire is straightened. When positioned for drilling, the guidewire tip can be exposed about 1 to about 2 mm from the distal end of the dilator. Alternatively, in some embodiments, the guidewire may not have a J-shape configuration. In such embodiments, it may not be necessary to move the guidewire relative to the sheath to straighten or configure the guidewire for drilling. Therefore, 1204 can be omitted.

[0135]

[0178] At 1206, the distal end (e.g., tip) of the guidewire is positioned against tissue. In some embodiments, the tissue is a portion of the atrial septum of the heart. In some embodiments, the sheath may be a steerable sheath and / or dilator and thus may be utilized to position or direct the guidewire toward the tissue, for example, by actuating a steering mechanism (e.g., a pull wire) on the sheath to deflect a distal portion of the seal. In some embodiments, a pull-down technique is performed in which the distal end of the dilator is directed toward the fossa ovalis (FO) and tenting of the tissue (e.g., the septum) (e.g., as shown in FIG. 8B) is facilitated via fluoroscopy and / or ultrasound imaging. In some embodiments, after tenting is performed, the operator may desire to reposition the dilator. To do so, the guidewire can be re-advanced into the SVC and the pull-down technique can be repeated.

[0136]

[0179] At 1208, energy delivery is activated to perforate the tissue. The perforation is formed by the tip of the guidewire delivering energy to the tissue to form the perforation. In some embodiments, electrosurgical energy is applied by activating a button or other actuator (e.g., button 422b) connected to the electrosurgical interface. In some embodiments, the perforation is formed by applying energy and applying slight pressure to the tissue with the guidewire. Once a puncture hole is formed in the tissue, energy delivery is stopped. In some embodiments, the formation of the puncture hole can be confirmed by imaging and / or tactile sensing.

[0137]

[0180] At 1210, a guidewire is advanced through the fenestration formed at 1208. In some embodiments, the guidewire transitions back to its curved configuration (e.g., as shown in FIG. 8C ). In some embodiments, the guidewire is advanced through the FO and positioned within the left atrium or pulmonary vein. At 1212, a sheath populated with a dilator can be advanced over the guidewire to dilate the fenestration. In some embodiments, the dilator is advanced through the FO and positioned within the left atrium.

[0138]

[0181] In some embodiments, at 1214, the dilator and electrosurgical interface can be retracted and removed, and additional devices (e.g., catheters and / or sheaths) can be advanced over the guidewire into the left atrium (or other target anatomical structure).

[0139]

[0182] In some embodiments, an outer sheath may be positioned around the dilator and / or guidewire and advanced into the left atrium, for example, simultaneously with or immediately after the dilator. The outer sheath may be positioned over the dilator and / or guidewire after the perforation is formed, dilated, and the electrosurgical interface is removed from the proximal end of the dilator. Alternatively, the outer sheath may be positioned over the dilator from the beginning of the procedure and used with the dilator at 1204, 1206, and 1212. In such embodiments, the outer sheath may be used to provide an access passageway or channel to the left atrium. The dilator and guidewire are removed from the outer sheath, while the sheath lumen remains in the left atrium. At 1214, a medical device (e.g., a catheter, etc.) is advanced through the sheath lumen to the target site for treatment.

[0140]

[0183] In some embodiments, a therapeutic ablation catheter is advanced into the left atrium so that pulmonary vein isolation can be performed. Once the procedure is performed, the medical device is withdrawn.

[0141]

[0184] 13 and 14 , it may be advantageous to vary the energy delivered from a generator (e.g., functionally and / or structurally similar to generator 110 of FIG. 1 ) to a guidewire (e.g., functionally and / or structurally similar to energy delivery element 124 of FIG. 1 ). In some embodiments, it may be desirable to vary the energy delivered to the guidewire tip based on a measured characteristic, such as temperature. This can help avoid heat buildup at the distal tip of the guidewire, thereby preventing undesirable microbubble formation. In some embodiments, it may be desirable for the guidewire to deliver varying amounts of energy to tissue. For example, if the distal tip of the guidewire is aligned with or slightly (e.g., about 1 mm) beyond the tip of the sheath, the effective surface area of ​​the guidewire is reduced, which can cause high potential current densities and therefore heating near the guidewire tip. As the guidewire extends from the sheath, the exposed surface area of ​​the guidewire increases, thereby reducing current density. To control potential changes in current density, it may be beneficial to vary the energy delivered to the guidewire to prevent inadvertent damage to tissue by the guidewire.

[0142]

[0185] 13 shows a flowchart of a method 1300 of varying RF power being delivered to a guidewire, according to an embodiment. Method 1300 includes modifying the power based on at least one characteristic associated with the guidewire. In some embodiments, the guidewire can include at least one sensor for measuring the at least one characteristic (e.g., condition of the guidewire, temperature). In some embodiments, the sensor can be configured to capture data indicative of the at least one characteristic and transmit the data to the generator, and the generator can adjust the energy being delivered to the guidewire in response to receiving the data.

[0143]

[0186] At 1302, method 1300 includes delivering RF power to a guidewire via an RF generator. In some embodiments, the amount of RF power delivered to the guidewire can be predetermined. In some embodiments, the amount of RF power delivered to the guidewire can be determined based on predetermined parameters (e.g., patient parameters, device parameters, etc.). At 1304, method 1300 includes detecting at least one characteristic associated with the guidewire. In some implementations, the at least one characteristic can be RF current, RF power, temperature, current density, pressure, current, voltage, etc. In some implementations, the at least one characteristic can be a state of the guidewire. For example, the state can include being inside a sheath, beginning to advance out of a sheath, engaging tissue, etc. As another example, the at least one characteristic can include current density at / around the tip of the guidewire.

[0144]

[0187] At 1306, method 1300 includes modifying the RF power based on at least one characteristic. Modifying the RF power may include modifying output power, peak-to-peak voltage, duty cycle, etc. For example, if the temperature at the tip of the guidewire is determined to exceed a predetermined threshold, the RF power may be modified to deliver less power to the guidewire. As another example, if a pressure sensor detects that the septum of the heart has been punctured, the RF power may be reduced to reduce the possibility of accidental injury. As another example, the RF power may be modified based on the current density at / around the tip of the guidewire and based on the position of the guidewire tip. For example, if the guidewire tip is contacting the heart wall and the current density is higher than desired (e.g., such that there is a risk of lesion formation), the RF power can be reduced. After the RF power is modified, method 1300 includes, at 1308, delivering the modified RF power to the guidewire. After RF power is delivered to the guidewire, method 1300 can return to 1304 to again detect at least one characteristic associated with the guidewire. Repeating steps 1304-1308 allows the system to dynamically change based on the detected at least one characteristic to reduce the likelihood of tissue damage.

[0145]

[0188] FIG. 14 shows a flowchart of a method 1400 of delivering RF power to a guidewire, according to an embodiment. Method 1400 includes varying power to the guidewire based on a power schedule, thereby allowing predetermined amounts of energy to be delivered during different stages of a procedure. In some embodiments, the power schedule is predetermined. In some embodiments, the treatment schedule can be modified based on the patient, device, etc. In some embodiments, the treatment schedule can be user-defined. At 1402, method 1400 includes delivering RF power to the guidewire via the RF generator at a first power parameter for a first time period. At 1404, method 1400 includes delivering RF power to the guidewire via the RF generator at a second power parameter for a second time period. At 1406, method 1400 optionally includes delivering RF power to the guidewire via the RF generator at a third power parameter for a third time period. In some embodiments, method 1400 can include the additional step of delivering RF power to the guidewire at an additional power parameter for an additional time period. The power parameter can correspond to a duty cycle. The period can correspond to a duration associated with manipulation of the guidewire. For example, the first power parameter can include a 10% duty cycle and the second power parameter can include a 50% duty cycle, with the first period being 25% of the duration of treatment and the second period being 75% of the duration of treatment.

[0146]

[0189] Additionally or alternatively, in some embodiments, the generator (e.g., generator 110 as described herein) can detect when the current density at the distal end of the guidewire decreases (e.g., as the conductive surface area increases due to dissecting the tissue) and can be adapted to deliver more current up to a predefined or user-programmed limit. If the wire exposes a smaller surface area, less current may be required, but as the wire extends into the tissue, the increasing surface area may require more current to maintain an effective current density to perforate the tissue. Once the wire is fully deployed (e.g., 1 cm from the tip of a dilator or other insulated shaft), even high RF power will not result in inadvertent tissue damage because the current density is so low.

[0147]

[0190] It should be understood that the examples and figures in this disclosure serve for illustrative purposes, and that deviations and modifications can be constructed and deployed in accordance with the teachings herein without departing from the scope of the present invention. For example, while the systems disclosed herein are shown as having a monopolar configuration in which the electrical circuit is completed by a remotely located return electrode located outside the patient's body, in alternative embodiments, such systems can have a bipolar configuration in which the return electrode is located inside the patient's body, such as, for example, a metal ring electrode located on a sheath, dilator, or catheter.

[0148]

[0191] As used herein, the terms "about" and / or "approximately," when used in conjunction with a numerical value and / or range, generally refer to a numerical value and / or range that is close to the stated numerical value and / or range. In some cases, the terms "about" and "approximately" mean within ±10% of the stated value. For example, in some cases, "about 100 units" may mean within ±10% of 100 (e.g., 90-110). The terms "about" and "approximately" may be used interchangeably.

[0149]

[0192] Some embodiments described herein relate to computer storage products comprising a non-transitory computer-readable medium (sometimes referred to as a non-transitory processor-readable medium) having instructions or computer code for performing various computer-implemented operations. The computer-readable medium (or processor-readable medium) is non-transitory in the sense that it does not itself comprise a transitory propagating signal (e.g., a propagating electromagnetic wave that carries information in a transmission medium such as space or a cable). The medium and computer code (sometimes referred to as code or algorithms) may be designed and constructed for a specific purpose or purposes. Examples of non-transitory computer-readable media include, but are not limited to, magnetic storage media such as hard disks, floppy disks, and magnetic tape; optical storage media such as compact disks / digital video disks (CDs / DVDs), compact disk read-only memories (CD-ROMs), and holographic devices; magneto-optical storage media such as optical disks; carrier wave signal processing modules; and hardware devices specially configured to store and execute program code, such as application-specific integrated circuits (ASICs), programmable logic devices (PLDs), read-only memory (ROM), and random access memory (RAM) devices. Other embodiments described herein relate to computer program products, which may include, for example, the instructions and / or computer code disclosed herein.

[0150]

[0193] The systems, devices, and / or methods described herein may be implemented by software (executed in hardware), hardware, or a combination thereof. Hardware modules may include, for example, general-purpose processors (or microprocessors or microcontrollers), field-programmable gate arrays (FPGAs), and / or application-specific integrated circuits (ASICs). Software modules (executed in hardware) may be expressed in various software languages ​​(e.g., computer code), including C, C++, Java, Ruby, Visual Basic, and / or other object-oriented, procedural, or other programming languages ​​and development tools. Examples of computer code include, but are not limited to, microcode or microinstructions, machine instructions such as those produced by a compiler, code used to generate web services, and files containing higher-level instructions executed by a computer using an interpreter. Further examples of computer code include, but are not limited to, control signals, encryption code, and compression code.

[0151]

[0194] The specific examples and descriptions herein are exemplary in nature, and embodiments may be developed by those skilled in the art based on the teachings herein without departing from the scope of the invention, which is limited only by the appended claims.

Claims

1. A guidewire, a conductive distal tip configured to deliver radio frequency (RF) energy to a septum of a subject to form a perforation through the septum; a conductive core coupled to the distal tip, the conductive core configured to conduct the RF energy to the distal tip; a conductive outer portion disposed near the distal tip, the conductive outer portion configured to be coupled to the distal tip via the conductive core; an insulating collar disposed between the distal tip and the conductive outer portion; Equipped with the guidewire is configured to extend distally from the insulated shaft a first distance to expose the distal tip and enable the distal tip to deliver the RF energy and form the perforation; The guidewire is further configured to extend distally from the insulated shaft a second distance greater than the first distance to expose the distal tip and at least a portion of the conductive outer portion, increasing the exposed surface area of ​​the conductive portion of the guidewire and thereby reducing current density along the conductive portion.

2. The guidewire of claim 1 , wherein the conductive core and the distal tip are formed of the same material.

3. 3. The guidewire of claim 1, further comprising a non-conductive outer portion disposed proximally of the conductive outer portion, the non-conductive outer portion configured to be grasped by a user to advance the guidewire distally.

4. The guidewire of claim 3 , wherein the non-conductive outer portion comprises a polymer layer.

5. 5. The guidewire of claim 1, wherein the conductive outer portion comprises gold plating configured to conduct heat away from the distal tip when the distal tip is delivering the RF energy.

6. The guidewire of any one of claims 1 to 5, wherein the conductive outer portion comprises a metal coil.

7. The guidewire of any preceding claim, wherein the conductive outer portion comprises a conductive polymer.

8. The guidewire of any one of claims 1 to 7, wherein the conductive outer portion comprises one or more openings formed in an insulating coating disposed over the conductive core.

9. The guidewire according to any one of claims 1 to 8, wherein the insulating collar is disposed over a portion of the metal coil.

10. 10. The guidewire of claim 9, wherein the metal coil in the region having the insulating collar is compressed or stretched relative to other portions of the metal coil.

11. The guidewire of any one of claims 1 to 10, wherein the insulating collar has a length of about 1 mm to about 20 mm.

12. The guidewire of any one of claims 1 to 11, wherein the first distance is less than about 10 mm.

13. 13. The guidewire of claim 1, wherein the insulating collar comprises a thermally conductive material configured to conduct heat away from the distal tip when the distal tip is delivering the RF energy.

14. 1. An apparatus comprising: an insulated 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 insulated shaft to expose a distal tip of the guidewire, the distal tip of the guidewire configured, upon exposure, to deliver radio frequency (RF) energy to a septum of a subject to form a perforation through the septum; an electrosurgical interface coupled to the proximal end of the insulated shaft and to a generator, the electrosurgical interface including a passageway aligned with the lumen of the insulated shaft such that the guidewire can extend through the passageway and the lumen of the insulated shaft, the electrosurgical interface configured to establish an electrical coupling between the generator and the guidewire and to maintain the electrical coupling while the guidewire is advanced distally to the distal end of the insulated shaft; an actuator configured to, in response to being actuated when the distal tip is exposed, send a signal to the generator causing the generator to generate a voltage output to deliver to the guidewire via the electrical coupling to deliver the RF energy to the distal tip to form the perforation; An apparatus comprising:

15. the passageway of the electrosurgical interface is configured to contain a conductive fluid, and the guidewire further includes a conductive outer portion electrically coupled to the distal tip; The apparatus of claim 14, wherein the electrosurgical interface is configured to establish the electrical coupling when the conductive outer portion is disposed within the conductive fluid.

16. 16. The device of claim 15, wherein the guidewire further includes a non-conductive portion disposed proximal to the conductive portion, the non-conductive portion configured to be grasped by a user to advance the guidewire.

17. The apparatus of claim 15, wherein the electrosurgical interface includes an electrode coupled to the generator and in contact with at least one of the conductive fluid or the conductive outer portion of the guidewire.

18. 16. The device of claim 15, wherein the guidewire further comprises a core wire coupled to the distal tip, the conductive outer portion of the guidewire being electrically coupled to the distal tip via the core wire.

19. 20. The device of claim 18, wherein the guidewire further includes an insulating coating disposed on the core wire along at least a portion of the core wire, and the conductive outer portion of the guidewire includes at least one opening formed in the insulating coating.

20. 20. The device of claim 18, wherein the conductive outer portion of the guidewire comprises a conductive coating or coil disposed over the core wire.

21. the guidewire further includes an electrically conductive outer portion disposed near the distal tip; the conductive outer portion is electrically coupled to the distal tip; 21. The device of any one of claims 14-20, wherein the guidewire is further configured to advance distally relative to the insulated shaft after the distal tip forms the perforation to expose the conductive outer portion and reduce the current density of the RF energy at the distal tip.

22. 22. The device of claim 21, wherein the guidewire further comprises an insulating collar disposed between the distal tip and the conductive outer portion.

23. 23. The apparatus of claim 22, wherein the insulating collar has a length of about 1 mm to about 20 mm.

24. 24. The device of any one of claims 14 to 23, wherein the insulated shaft is a dilator configured to be advanced distally to dilate the perforation after the distal tip has formed the perforation, thereby enabling a surgical instrument to be advanced along the guidewire and through the perforation to a target site.

25. the electrosurgical interface further comprising a housing; The device of any one of claims 14 to 24, wherein the actuator is disposed on the housing and configured to slide along the housing when actuated.

26. The device of any one of claims 14 to 25, wherein the guidewire is configured to form an atraumatic shape when advanced distally relative to the insulated shaft.

27. 1. A system comprising: generator and 1. An electrosurgical device comprising: a guidewire configured to deliver radio frequency (RF) energy to a septum of a subject to perforate the septum; an electrosurgical interface configured to be coupled to the generator, the electrosurgical interface including a passageway configured to slidably receive the guidewire such that the guidewire and the electrosurgical interface can move relative to one another, the electrosurgical interface configured to establish an electrical coupling between the guidewire and the generator and to maintain the electrical coupling while the guidewire is moved relative to the electrosurgical interface; an electrosurgical device comprising: Equipped with The generator: generating and delivering a voltage output to the guidewire via the electrical coupling in response to receiving an activation signal; Monitoring a characteristic associated with the electrosurgical device and modulating the voltage output based on the characteristic. The system is configured as follows:

28. the guidewire further comprises one or more temperature sensors disposed at a distal tip of the guidewire; the characteristic being monitored by the generator is a temperature associated with the distal tip of the guidewire; the generator is configured to modulate the voltage output by modulating the voltage output to maintain the temperature associated with the distal tip at a predetermined setpoint temperature; 28. The system of claim 27.

29. 29. The system of claim 28, wherein the predetermined setpoint temperature is between about 55 degrees Celsius and about 80 degrees Celsius.

30. a return electrode operatively connected to the generator and the electrosurgical device; the characteristic being monitored by the generator is the impedance of a circuit formed by the generator, the electrosurgical device, and the return electrode; The generator: In response to determining that the impedance is greater than a predetermined threshold, reducing the voltage output such that power associated with the circuit is below a predetermined value.

30. The system of any one of claims 27 to 29, configured to modulate the voltage output by

31. 31. The system of claim 30, wherein the predetermined value is between about 5 W and about 100 W.

32. 32. The system of any one of claims 27 to 31, wherein the electrosurgical device further includes an insulated shaft defining an internal lumen, the guidewire configured to be slidably received within the internal lumen.

33. the passageway of the electrosurgical interface is configured to contain a conductive fluid, and the guidewire further includes a conductive outer portion electrically coupled to the distal tip; the electrosurgical interface is configured to establish the electrical coupling when the conductive outer portion is disposed within the conductive fluid. A system according to any one of claims 27 to 32.

34. The system of claim 33, wherein the electrosurgical interface includes an electrode coupled to the generator and in contact with at least one of the conductive fluid or the conductive outer portion of the guidewire.

35. The system of any one of claims 27 to 34, wherein the electrosurgical device further includes an actuator, the actuator configured to generate the activation signal in response to being actuated.

36. 36. The system of any one of claims 27 to 35, wherein the guidewire further comprises an insulating collar disposed near the distal tip of the guidewire, the insulating collar having a length of about 1 mm to about 20 mm.

37. 1. A method comprising: extending a guidewire disposed within an insulating sheath a first distance distal to a distal end of the insulating sheath, wherein the guidewire and the insulating sheath are positioned adjacent to a tissue wall; placing a distal tip of the guidewire against the tissue wall; After positioning the distal tip of the guidewire against the tissue wall, delivering radio frequency (RF) energy to the tissue wall via the distal tip; further extending the guidewire distally while delivering the RF energy to form a perforation through the tissue wall; exposing at least a portion of the conductive outer portion of the guidewire in response to extending the guidewire a second distance distal to the distal end of the insulating sheath, thereby increasing an exposed conductive surface area of ​​the guidewire after forming the perforation; A method comprising:

38. 38. The method of claim 37, wherein increasing the exposed conductive surface area of ​​the guidewire reduces current density at the distal tip of the guidewire.

39. 39. The method of claim 37 or 38, wherein the tissue wall is a septum, and the distal tip of the guidewire is used to tent the septum before delivering the RF energy to the septum.

40. the insulating sheath is a dilator; advancing the dilator over the guidewire and through the fenestration to dilate the fenestration; 40. The method of any one of claims 37 to 39, further comprising:

41. retracting the insulating sheath after forming the perforations; advancing a surgical instrument over the guidewire and through the fenestrations to advance the surgical instrument to a target site; The method of any one of claims 37 to 40, further comprising:

42. performing a surgical procedure using the surgical instrument after advancing the surgical instrument to the target site.

42. The method of claim 41, further comprising:

43. An energy delivery element for perforating biological tissue, comprising: a wire comprising a distal tip including a first conductive region, a first insulating region disposed immediately proximal to the conductive tip, and a second conductive region disposed immediately proximal to the first insulating region; Equipped with when an energy delivery device is energized by a generator (having any standard configuration) and at least partially contained within an insulating tube, said energy delivery device exhibits a current density that is a function of displacement relative to the distal end of said insulating tube; When the distal tip including the first conductive region extends less than 10 mm beyond the end of the insulating tube, the current density is 45 A / cm ２ greater than 250 A / cm ２ smaller than When the distal conductive tip extends 10 mm beyond the end of the insulating tube, the current density associated with the first conductive region is 60 A / cm ２ and the current density associated with the second conductive region is less than 60 A / cm ２ smaller than When the distal conductive tip extends 20 mm beyond the end of the insulating tube, the current density distributed from the first conductive region is 25 A / cm ２ and the current density distributed from the second conductive region is in a range smaller than 25 A / cm ２ is smaller than Energy delivery element.

44. the length of the distal conductive tip is between 0.25 mm and 30 cm; The length of the first insulating region is 2 mm to 2 cm; the length of the proximal conductive region is between 5 mm and 30 mm; 44. The energy delivery element of claim 43.

45. 45. The energy delivery element of claim 44, wherein the distal conductive tip is uncoated.

46. 45. The energy delivery element of claim 44, wherein the first insulating region is coated with a dielectric material.

47. 45. The energy delivery element of claim 44, wherein the proximal conductive region is uncoated, partially coated, or coated with a conductive polymer.

48. 48. The energy delivery element of any one of claims 43 to 47, further comprising a second insulating region disposed proximal to the proximal conductive region.

49. 50. A method of puncturing biological tissue comprising providing an energy delivery element according to any one of claims 43 to 48, disposing the energy delivery element within a dilator; advancing the distal tip over the dilator; energizing the energy delivery element; Monitoring the impedance; A method comprising:

50. 1. An electrosurgical interface comprising: a housing defining a lumen and containing an electrically conductive element, the electrically conductive element and the lumen sized to slidably receive an energy delivery element; a current-carrying wire connected to the conductive element; an actuator for modulating the energy delivered by the current-carrying wire; Equipped with An electrosurgical interface, wherein when the actuator is in an energized state, radio frequency (RF) energy is transmitted to the energy delivery element through the conductive element.

51. 51. An electrosurgical interface according to claim 50, wherein the RF energy is transmitted to the energy delivery element via the conductive element and through at least one opening in an insulating coating of the energy delivery element.

52. An electrosurgical interface according to claim 51 , wherein the at least one opening comprises a plurality of holes.

53. An electrosurgical interface according to claim 51 , wherein the at least one opening includes a slot.

54. An electrosurgical interface according to claim 51 , wherein the at least one opening includes a helical slot.

55. An electrosurgical interface according to claim 51 , wherein the at least one opening includes a plurality of slots.

56. An electrosurgical interface according to claim 50, wherein the RF energy is transmitted to the energy delivery element through a conductive polymer coating of the energy delivery element.

57. An electrosurgical interface according to claim 50, wherein the RF energy is transmitted to the energy delivery element via the conductive element through holes in a conductive coating of the energy delivery element.

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