Systems and methods for a myocardial accessor catheter for intramyocardial ablation

Abstract

A guiding catheter system for performing intramyocardial ablation is provided. In one example, a guiding catheter system for intramyocardial navigation and ablation includes an accessor catheter including a shaft, the shaft including one or more lumens, the one or more lumens sized to accommodate an effector configured to perform intramyocardial navigation and an anchor system.

Description

Attorney Docket No. NIH24305PCTSYSTEMS AND METHODS FOR A MYOCARDIAL ACCESSOR CATHETER FOR INTRAMYOCARDIAL ABLATIONCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to U.S. Provisional Patent Application No. 63 / 716.158, filed November 4. 2024, and entitled “SYSTEMS AND METHODS FOR A MYOCARDIAL ACCESSOR CATHETER FOR INTRAMYOCARDIAL ABLATION,” the entire contents of which is hereby incorporated by reference for all purposes.FIELD

[0002] The present description relates generally to an apparatus for deep myocardial ablation, and more specifically to an accessor catheter for delivering an ablation catheter for deep myocardial ablation.BACKGROUND / SUMMARY

[0003] Some intramyocardial structural heart procedures use catheter-based cardiac devices, which may be navigated into a targeted position within the heart muscle via a freely steered guidewire. As one example, septal scoring along the midline endocardium (e.g., SESAME) is a transcatheter myotomy procedure that may be used to relieve or prevent a left ventricular outflow tract (LVOT) obstruction by splaying the circumferential myofibers of the septal myocardium with a flying-V laceration surface formed by an ensnared guidewire tip previously navigated through the interventricular septum. Another example intramyocardial procedure includes myocardial intramural remodeling by transvenous tether (MIRTH), which is a transcatheter ventricular remodeling procedure.

[0004] The inventors herein have recognized that delivery of intramyocardial catheter and / or guidewire systems may be improved if such systems are delivered with a device that achieves temporary reversible but strong fixation into the myocardium that allows the intramyocardial catheter and / or guidewire system to be pushed hard into the myocardium.

[0005] In one example, a guiding catheter system for intramyocardial navigation and ablation is provided. The guiding catheter system includes an accessor catheter including a shaft, the shaftAttorney Docket No. NIH24305PCT including one or more lumens, the one or more lumens sized to accommodate an effector configured to perform intramyocardial navigation and an anchor system.

[0006] It should be understood that the brief description above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The present disclosure will be better understood from reading the following description of non-limiting embodiments, with reference to the attached drawings, wherein below:

[0008] FIG. 1 depicts an example ablation catheter system;

[0009] FIG. 2 depicts a first view of an ablation catheter and navigation guidewire of the ablation catheter system of FIG. 1;

[0010] FIG. 3 depicts the ablation catheter and navigation guidewire of FIG. 2 arranged within an accessor catheter of a guiding catheter system;

[0011] FIG. 4 depicts hub ends of the ablation catheter system and the guiding catheter system;

[0012] FIG. 5 depicts another view of the hub ends;

[0013] FIG. 6 depicts a magnified view of a proximal end of the accessor catheter;

[0014] FIGS. 7-10 schematically show the guiding catheter system facilitating access to the myocardium and supporting the ablation catheter system therein;

[0015] FIG. 11 is a flow chart illustrating a method for performing an ablation procedure with an ablation catheter system guided by a guiding catheter system as disclosed herein; and

[0016] FIG. 12 schematically shows an example kit including aspects of the guiding catheter system as disclosed herein.DETAILED DESCRIPTION

[0017] The following description relates to a guiding catheter system configured to deliver an effector configured to traverse the myocardium. In the examples presented herein, the guidingAttorney Docket No. NIH24305PCT catheter system is explained as being configured to deliver an effector configured to treat ventricular tachycardia (VT). However, other effectors may be delivered with the guiding catheter system disclosed herein, such as microcatheters and / or guidewires for performing procedures such as SESAME, MIRTH, and the like. Intramyocardial navigation may create counter-force that displaces equipment and retards device advancement. Thus, the guiding catheter system disclosed herein provides counter-traction and device stability to facilitate advancement of guidewires and / or catheters within the myocardium.

[0018] As explained above, the effector delivered by the guiding catheter system may include an ablation catheter system for treating VT that comprises an electrically insulated electrodeguidewire and an ablation microcatheter, at least in some examples. The effector / ablation catheter system may hereafter be referred to as VINTAGE (Ventricular Intramyocardial Navigation for Tachycardia Ablation Guided by Electrograms). VT can originate from damaged or scarred tissue or areas of abnormal automaticity located within the ventricles of the heart that disrupt electrical function necessary for normal heart function. For example, regions of scar and slow conduction can form the substrate for reentrant conduction pathways underlying VT. Ablation of key scarred or damaged tissue targets with radio-frequency (RF) energy may block the transmission of pathological electrical signals thereby treating VT. Current systems of ablation have their own limitations. For example, endocardial monopolar ablation may have difficulty reaching deep targets whereas epicardial monopolar ablation is hindered by the presence of thick epicardial fat and the threat of injury to nearby coronary arteries.

[0019] Thus, the VINTAGE system disclosed herein addresses these issues via guidewire navigation to intramyocardial targets and ablation in the myocardium with an ablation electrode. As shown in FIGS. 1-2, the VINTAGE system may include an ablation microcatheter including an ablation electrode and one or more mapping / tracking electrodes, and configured for coaxial arrangement with a navigation guidewire. The ablation microcatheter may be sized to accommodate the navigation guidewire in a central lumen and may include a fenestrated or segmented ablation electrode to facilitate irrigation, via irrigant in the central lumen, during ablation.

[0020] As mentioned above, intramyocardial navigation creates counter-force that displaces equipment and retards device advancement. Thus, the VINTAGE system may be guided to the myocardium and supported while traversing the myocardium by the guiding catheter system. AsAttorney Docket No. NIH24305PCT shown in FIGS. 3-6, the guiding catheter system may include an accessor catheter coaxially arranged in an outer catheter, with the accessor catheter configured to deliver an anchor system and an effector (e.g., the VINTAGE system). The accessor catheter and / or outer catheter may be deflectable to control the angle of engagement with the myocardium, and the anchor system may include a myocardial engagement component configured to engage the myocardium and provide support while the VINTAGE system is deployed into the myocardium for ablation, as shown in FIGS. 7-11.

[0021] The ablation microcatheter and the navigation guidewire of the VINTAGE system may be used to traverse the myocardium to reach an ablation target, guided by electrograms detected from the electrodes on the ablation microcatheter and guidewire, or by position information (e.g., spatial and / or geometric position information) encoded on electromagnetic fields generated by electroanatomic mapping systems. Irrigation with an electrolyte may be performed via the flush port and fenestrations / openings of the ablation microcatheter and ablation performed with the ablation electrode to alter the electrical and / or physicochemical characteristics of the target myocardial substrate. Aspects of the VINTAGE system, including the ablation microcatheter and the navigation guidewire and / or the accessor catheter, may be packaged in a kit, as shown in FIG. 12.

[0022] Turning now to the figures, FIG. 1 depicts an example of an effector in the form of an ablation catheter system 100 (also referred to as a VINTAGE system), in a first configuration. FIG. 1 (as well as FIGS. 2-10) includes a Cartesian coordinate system 199 to orient each view of the ablation catheter system 100 provided herein, hi the example shown in FIG. 1, the y-axis may be a vertical axis (e.g.. extending parallel to gravity with the positive y direction pointing in the direction of the arrow, away from ground), the x-axis of coordinate system 199 may be a longitudinal axis (e.g., horizontal axis), and / or the z-axis of coordinate system 199 may be a lateral axis, in one example. However, the axes may have other orientations, in other examples. When referencing direction, positive may refer to in the direction of the arrow of the x-axis, y-axis, and z-axis and negative may refer to in the opposite direction of the arrow of the x-axis, y-axis, and z- axis. An unfilled circle may represent an arrow and an axis facing away, or negative to, a view. However, it is to be appreciated that the ablation catheter system 100 may be held or used in any orientation without departing from the scope of this disclosure. Further, the term distal end may refer to a first end of the ablation catheter system 100 configured to be positioned within a heartAttorney Docket No. NIH24305PCT of a patient and the term proximal end may refer to a second end of the ablation catheter system 100 configured to remain external to the patient. In some examples, the patient may be human, however in other examples the patient may be nonhuman.

[0023] The ablation catheter system 100 includes an ablation microcatheter 102 that includes a shaft 101 (e.g., a polymer tube) including a body 103 and a tapered nosecone 106. The ablation microcatheter 102 further includes a first mapping electrode 104 coupled to the shaft 101 at a distal end of the ablation microcatheter 102, a fenestrated, conductive ablation electrode 108 coupled to the shaft 101 at the distal end (e.g., proximal the first mapping electrode 104), and a second mapping electrode 109 coupled to the shaft 101 proximal the ablation electrode 108. The ablation microcatheter 102 may have a generally cylindrical shape with a hollow interior to facilitate a coaxial arrangement of a navigation guidewire 110. The shaft 101, and specifically the tapered nosecone 106, may terminate at a distal tip 105 that has an opening through which the navigation guidewire 110 may extend. At the distal tip, the ablation microcatheter 102 may have a first inner cross-sectional diameter (e.g., along the z axis) in a range of 0.014-0.018 inches. The tapered nosecone 106 may taper in width / cross-sectional area along the x axis (and specifically may taper in the negative x direction). Accordingly, at least in some examples, the ablation microcatheter 102 may have a larger cross-sectional area in the body 103 (e.g., proximal of the first mapping electrode 104) than at the distal tip 105. For example, the ablation microcatheter 102, along its entirety other than the tapered nosecone 106, may have a second inner cross-sectional diameter (e.g., along the z axis) in a range of 0.021-0.035 inches and an outer cross-sectional diameter in a range of 0.025-0.038 inches. Each of the first mapping electrode 104 and the second mapping electrode 109 may be surface ring electrodes that extend radially around an entire circumference of the shaft 101 and have inner and outer diameters that match the inner and outer diameters of the ablation microcatheter mentioned above. However, other geometrical arrangements are possible without departing from the scope of this disclosure. For example, one or both of the first mapping electrode 104 and the second mapping electrode 109 may be semi-circular such that the electrode(s) extends radially around only half the circumference of the shaft 101. In the example illustrated in FIGS. 1 and 2, the first mapping electrode 104 may be positioned between the tapered nosecone 106 and the ablation electrode 108, though the first mapping electrode 104 may be positioned elsewhere on the ablation microcatheter 102 without departing from the scope of this disclosure. Further, in some examples, more than two mapping electrodes may be provided. TheAttorney Docket No. NIH24305PCT ablation microcatheter 102 may have a suitable length (e.g., along the x axis) to facilitate placement of the ablation microcatheter 102 in a patient and specifically to facilitate placement of the distal end of the ablation microcatheter 102 in a heart of the patient while the proximal end of the ablation microcatheter 102 remains external to the patient. The ablation microcatheter 102 may include an opening at the distal tip 105 to allow insertion and removal of the navigation guidewire 110 as well as an opening at the proximal end. At the proximal end, the ablation microcatheter 102 may include and / or be coupled to various hardware 112 to facilitate navigation of the ablation microcatheter 102 as well as fluid irrigation during an ablation procedure.

[0024] The hardware 112 may include an irrigation port 112a, electrode connectors, an RF connector, and a hemostatic valve. In some examples, the hemostatic valve may be integrated with the ablation microcatheter 102, or the hemostatic valve may be detachable and the ablation microcatheter 102 may include a connector (e.g., a Luer lock connector) to facilitate coupling of the hemostatic valve. The electrode connectors may be configured to couple to a signal processor, for example, via one or more first connections 118 (e.g., signal wires). The first mapping electrode 104 and the second mapping electrode 109 may be coupled to the electrode connectors via a suitable connection, such as wires extending along or within a wall forming the ablation microcatheter 102 (e.g., within the body 103). In some examples, the electrode connectors may include terminals of the wires that are accessible to the one or more first connections 118. In other examples, the electrode connectors may include external connector(s) configured to mate with a corresponding connection of the one or more first connections 118. Navigation of the ablation microcatheter 102 may be guided by x-ray fluoroscopy, electroanatomic mapping (EAM), and / or electrocardiographic radial depth navigation (EDEN), and / or intracardiac ultrasound. EDEN provides real-time, depth- specific unipolar intramyocardial electrogram patterns that indicate intramural radial position during microcatheter and guidewire navigation based on output from the first mapping electrode 104, the second mapping electrode 109, and / or an exposed conductor of the navigation guidewire, explained below. The RF connector may facilitate coupling to an RF generator 208, explained below.

[0025] Thus, the ablation microcatheter 102 includes one or more mapping electrodes allowing intramyocardial EAM and / or EDEN tracking and a fenestrated ablation electrode to allow RF ablation and irrigation during RF ablation. The ablation microcatheter 102 is capable of tracking over the navigation guidewire 110, is capable of intramyocardial pacing, is capable ofAttorney Docket No. NIH24305PCT deep intramyocardial positioning under x-ray, EAM, and EDEN guidance, is capable of RF ablation, and is capable of infusing electrolyte around the ablation electrode. The ablation microcatheter 102 includes electrode connectors for EAM and a connector for an RF generator for ablation. The ablation microcatheter 102 may be electrically insulated from the navigation guidewire and any surrounding catheters and media. The ablation microcatheter 102 may have a "short" rotating hemostatic valve / adaptor (e.g., of less than 2cm) and allows coaxial placement of the navigation guidewire 110 as well as a sidearm (e.g., the irrigation port 112a) to allow electrolyte infusion. The ablation microcatheter 102 may have a length of 135-175 cm.

[0026] The navigation guidewire 110 may comprise a thin (e.g., having an outer diameter in a range from 0.01 inches to 0.02 inches) cylindrical material having a stiffness (or flexibility) that enables insertion into and navigation within the myocardium. For example, the navigation guidewire 110 may comprise stainless steel and / or nickel-titanium alloy (e.g., Nitinol) and / or another suitable biocompatible alloy, and may have customized or variable stiffness and diameter along its length for increased pushability and kink resistance. Further, a length of the navigation guidewire 110 is electrically insulated except for an exposed conductor 111 at the distal end of the navigation guidewire 110 and a connection point at the proximal end of the navigation guidewire 110. For example, the navigation guidewire 110 may be coated with one or more insulators except for the exposed conductor 111 and the connection point that electrically couples the exposed conductor to an electrode connector 116 via the electrically conductive transmission line. In this way, the navigation guidewire 110 may include an insulated region and an uninsulated region (e.g., the exposed conductor 111). The electrode of the navigation guidewire (e.g., the exposed conductor 111) may be a unipolar electrode in some examples. The electrode connector 116 may be coupled to the signal processor, for example, via a second connection 122 (e.g., a signal wire). The electrode connector 116 may be configured to limit the mechanical limitation on the operator torqueing the navigation guidewire during operation / advancement / retraction, to ensure tactile feedback and to minimize physical constraints on torque / advancement / withdrawal. The navigation guidewire 110 may have a tip stiffness (measured by lateral deflection at a fixed distance from the tip, such as 10mm) at the distal end of the navigation guidewire 110 ranging from 6 to 60 g, such as 20-40 g, allowing a short l-2mm x 30° "CTO" curve, as well as a straight tip (e.g., at the proximal end), each with electrical insulation to allow EDEN and EAM tracking. The navigation guidewire 110 may include radiopaque markers allowing fluoroscopic tracking. The distal tip ofAttorney Docket No. NIH24305PCT the navigation guidewire 110 has an insulation-free segment ~lmm in length, for EAM / EDEN; the proximal tip of the navigation guidewire 110 has an insulation-free segment ~10mm in length, for attachment to an electrode connector 116 to allow EAM / EDEN. The length of the navigation guidewire 110 may be 200-300cm, in some examples. In some examples, the electrode connector 116 may be detachable.

[0027] Thus, the ablation catheter system 100 in the first configuration includes a coaxial arrangement of the ablation microcatheter 102 and the navigation guidewire 110, with the navigation guidewire 110 accommodated within the ablation microcatheter 102. During an ablation procedure, the ablation catheter system 100 may be navigated to the heart (e.g., via a guiding catheter system disclosed herein) and advanced into the myocardium, to any target within the wall of the left ventricle, for example. Navigation of the ablation catheter system 100 may be guided by x-ray fluoroscopy, EAM, EDEN, and / or intracardiac echocardiography (ICE). Additional details about navigating the ablation catheter system 100 are provided below.

[0028] Once the ablation microcatheter 102 reaches the target, ablation of the target may be performed via the ablation electrode 108. The relatively large diameter of the ablation microcatheter 102 (and the irrigation port 112a) relative to the relatively small diameter of the navigation guidewire 110, as well as fenestrations of the ablation electrode 108, may facilitate irrigation of the target with an electrolyte prior to and during ablation. The irrigation may be facilitated by an irrigation pump 206 fluidly coupled to the irrigation port 112a. When the irrigation pump 206 is coupled to the irrigation port 112a and the irrigation pump 206 is activated, the electrolyte may be pumped through the interior of the ablation microcatheter 102 and out of the fenestrations of the ablation electrode 108. The irrigation pump 206 may be capable of infusing intramyocardial ionic irrigant (such as 0.9% (normal) or 0.45% (half-normal) saline solution). In some examples, the irrigation pump 206 may include timing and gating circuitry to automate initiation of infusion / infiltration / imgation approximately 1 minute before initiation of RF ablation, and continuing at approximately the same rate for the duration of the RF ablation. The irrigant may also be a caustic agent intended to effect adjunctive chemoablation, using agents such as alcohols or short-chain carboxylic acid such as acetic acid.

[0029] Ablation may be achieved via the RF generator 208 coupled to the ablation microcatheter 102, which may be activated to deliver RF energy to the target via the ablation electrode 108. The RF generator 208 may be capable of generating kilohertz AC radiofrequencyAttorney Docket No. NIH24305PCT waves ranging 10-100 W intended to achieve permanent thermal tissue injury. The RF generator 208 may include real-time impedance monitoring, a dispersive electrode, and attendant safety circuitry. In other examples, the RF generator 208 may include microsecond or nanosecond RF pulse trains intended to achieve non-thermal permanent tissue injury, sometimes described as "pulsed field ablation." Some examples may allow automatic modulation and cessation of energy based on pre-specified changes in impedance. In some examples, the RF generator may be configured to deliver microwaves. In this way, the ablation electrode may be configured to deliver RF, pulsed field, or microwave energy.

[0030] FIG. 2 shows a magnified view of the distal end of the ablation microcatheter 102 in the first configuration (e.g., with coaxial arrangement with the navigation guidewire), showing the distal tip 105, tapered nosecone 106. first mapping electrode 104. ablation electrode 108. second mapping electrode 109, and body 103. The first mapping electrode 104 may have a length along the x axis of 1-2 mm. The first mapping electrode 104 may be separated from the tapered nosecone 106 by a first insulating segment 202 (e.g., a first section of the polymer tube) and from the ablation electrode 108 by a second insulating segment 204 (e.g., a second section of the polymer tube). The ablation electrode 108 may be comprised of a hollow, circular segment of metal that has a length along the x axis of 10-15 mm. The ablation electrode 108 include a plurality of fenestrations (e.g., apertures), such as first fenestration 128, that extend through the metal of the ablation electrode. The number, size, shape, and placement of the fenestrations may be non-limiting and may be selected based on a desired irrigation rate, position of the target, and other considerations. As shown, the fenestrations may be circular and of equal diameter (e.g., 0.5-1 mm). The fenestrations may be arranged around the ablation electrode 108 in an even, repeating pattern. For example, the fenestrations may be arranged into a plurality of rows that extend longitudinally (e.g., along the x axis). Each row may include the same number of longitudinally-aligned, evenly-spaced fenestrations (e.g.. six). The rows may be axially offset from each other in an alternating pattern. For example, a first row may be axially offset relative to a second row, such that a first fenestration of the first row (e.g., the first fenestration 128) is closer to a distal edge of the ablation electrode 108 than a first fenestration of the second row (e.g., second fenestration 129). As such, the fenestrations are distributed into a plurality of radial groups that are longitudinally offset in an alternating pattern. For example, the first fenestration 128 may be included in a first radial group of circumferentially-aligned fenestrations that are evenly spaced around the circumference of theAttorney Docket No. NIH24305PCT ablation electrode 108. The second fenestration 129 may be included in a second radial group of circumferentially-aligned fenestrations that are evenly spaced around the circumference of the ablation electrode 108. Due to the offset pattern of the rows of fenestrations, the first fenestration 128 is not longitudinally- aligned with any fenestrations in the second radial group, but is instead longitudinally- aligned with a fenestration in a third radial group, a fifth radial group, etc. As such, the ablation electrode 108 may include a portion of metal between each pair of adjacent, longitudinally- aligned fenestrations and between each pair of adjacent, circumferentially- aligned fenestrations. The fenestrations may be distanced from each terminal edge of the ablation electrode by a suitable amount, such as 0.5-1 mm.

[0031] However, other configurations are possible, such as non-circular (e.g., rectangular) fenestrations, fenestrations of varying diameter and / or shape, and / or an uneven pattern of fenestrations. For example, the fenestrations may be distributed such that more fenestrations (or all of the fenestrations) are located on one side of the ablation electrode 108 to facilitate directed, asymmetrical irrigation. In some examples, the body 103 may include longitudinal grooves inside the inner lumen (e.g., on an inner surface of the body 103 / polymer tube) to enhance irrigation fluid delivery. Thus, the ablation electrode may include one or more openings to facilitate irrigation during ablation. The one or more openings may be static (e.g., fixed in size and position) or dynamic (e.g., the size of each opening may be adjustable and / or the one or openings may be exposed upon actuation of a particular component) and may be of any suitable shape, including but not limited to circular, semi-circular, oval, rectangular, spiral, helical, sinusoidal, clamshell, and the like.

[0032] The second mapping electrode 109 may have the same length as the first mapping electrode 104 (e.g., a length along the x axis of 1-2 mm). The second mapping electrode 109 may be separated from the ablation electrode 108 by a third insulating segment 205 (e.g., a third section of the polymer tube). The tapered nosecone 106. first insulating segment 202, the second insulating segment 204, the third insulating segment 205, and the body 103 may collectively form the shaft 101 (e.g., the polymer tube).

[0033] The first insulating segment 202, the first mapping electrode 104, the second insulating segment 204, the ablation electrode 108, the third insulating segment 205, the second mapping electrode 109, and the body 103 may all be circular and hollow with the same or substantially similar (e.g., within 5-10%) inner diameter, to thereby create an inner lumen that extends from theAttorney Docket No. NIH24305PCT proximal / hub end of the body 103 (shown in FIG. 4 and described in more detail below) to the tapered nosecone 106. Further, the tapered nosecone 106, the first insulating segment 202, the second insulating segment 204, the third insulating segment 205, and the body 103 may be comprised of the same material (e.g., polymer), at least in some examples. Likewise, the first mapping electrode 104, the ablation electrode 108, and the second mapping electrode 109 may all be comprised of the same material, such as platinum-iridium alloy, stainless steel alloy, titanium, gold-plate, etc. hr some examples, molybdenum-rhenium may be used to allow a lower profile. In some examples, the mapping electrodes may be partial ring electrodes, spiral electrodes (e.g., coils), strip electrodes, or have another suitable configuration. In still further examples, the shaft 101 may extend along the ablation electrode to form a lining on an inner surface of the ablation electrode. In such examples, the lining may include openings that match the openings of the ablation electrode.

[0034] The navigation guidewire 110 can be seen within the inner lumen of the ablation microcatheter 102 via the fenestrations of the ablation electrode 108. The size mismatch between the navigation guidewire 110 (e.g., diameter of 0.1-0.2 inches, such as 0.014 inches) and central lumen (e.g., diameter of 0.021-0.035 inches) may allow irrigant to be accommodated in the central lumen and be expelled out of the fenestrations of the ablation electrode 108 during ablation. The navigation guidewire 110 may extend out of the distal tip 105. Due to the tapering of the tapered nosecone 106, the size mismatch between the navigation guidewire 110 and the distal tip 105 may be relatively small, which may allow the ablation microcatheter 102 to slide over the navigation guidewire 110 but prevent flow of irrigant out of the distal tip 105.

[0035] FIG. 3 shows a view of a guiding catheter system 300 arranged with the ablation catheter system 100. The guiding catheter system includes an outer catheter 302, an accessor catheter 304, and an anchor system including an anchor shaft 306. To facilitate delivery of the ablation catheter system 100, the accessor catheter 304 may be coaxially arranged in the outer catheter 302, and the anchor shaft 306 may be arranged in the accessor catheter 304 along with the ablation microcatheter 102 and navigation guidewire 110 of the ablation catheter system 100. The guiding catheter system 300 may be flexible and deflectable, with each of the outer catheter 302, the accessor catheter 304, and the anchor shaft 306 being comprised of or including regions of flexible and / or deflectable material.Attorney Docket No. NIH24305PCT

[0036] The outer catheter 302 may have a cylindrical shape with a hollow interior to slidingly receive the accessor catheter 304. The outer catheter 302 may have an outer diameter in a range of 2.6-2.8mm (e.g.. 8-8.5 F; 0.10-0.11 inches), a usable length in a range of 100-130 cm, and an opening at the distal end though which the accessor catheter 304 is configured to extend. In some examples, the outer catheter 302 may include a distal deflectable portion with a variable radius of deflection (e.g., of 2-5 cm) and a deflection angle of 0-135 degrees.

[0037] The accessor catheter 304 may have a cylindrical shape with at least one hollow lumen to slidingly receive the anchor shaft 306 and / or the ablation microcatheter 102. In some examples, the accessor catheter 304 may have two hollow, non-concentric lumens, one to accommodate the anchor shaft 306 and another to accommodate the ablation microcatheter 102. In other examples, the accessor catheter 304 may have one lumen to accommodate both the anchor shaft 306 and the ablation microcatheter 102.

[0038] In the example shown herein, the accessor catheter 304 may have an outer diameter of 1.95-2.75mm (e.g., 6-8.3 F; 0.07-0.107 inches), a usable length of 110-135 cm, and two openings at each of the proximal and the distal ends to provide access to the two hollow lumens. In some examples, the accessor catheter 304 may have deflectable capabilities with a distal deflectable portion that has a radius of deflection (e.g., of 2-5 cm) and deflection angle 0-135 degrees. In still further examples, the accessor catheter 304 may have a fixed, 90-degree distal deflection. The accessor catheter 304 may include at least one distal electrode for EAM and / or EDEN. For example, the accessor catheter 304 may include a first electrode 308 at the distal tip of the accessor catheter 304 and a second electrode 310 spaced apart from the first electrode 308 by a suitable amount (e.g., 2-5 mm). Each of the first electrode 308 and the second electrode 310 may be similar to the mapping electrodes of the ablation microcatheter 102, e.g., surface ring electrodes with a length of l-2mm. However, other electrode configurations are possible, such as spiral electrodes, strip electrodes, partial ring electrodes, etc. Further, in some examples, one or both of the first electrode 308 and the second electrode 310 may be omitted.

[0039] The anchor shaft 306 may comprise a thin (e.g., having an outer diameter in a range from 0.01 inches to 0.02 inches) cylindrical material terminating at myocardial engagement component 312 at a distal end of the anchor shaft 306. In the illustrated example, the myocardial engagement component 312 may include a set of prongs, such as two or more sharp prongs (e.g., three, as shown) each having a length of approximately 10- 15mm and appropriate curvature toAttorney Docket No. NIH24305PCT form fish-hook shaped prongs when deployed. The set of anchor prongs may be configured to retract and deploy, such that the set of anchor prongs may be held along / in alignment with the anchor shaft 306 during navigation of the guiding catheter system 300 to the myocardium and then deployed to the position shown in FIG. 3 in order to engage the myocardium and anchor the guiding catheter system 300. However, other types of myocardial engagement components are possible, such as a corkscrew / helix with fixed or variable pitch and / or diameter. The corkscrew / helix may be referred to as a helical anchor, and may comprise a segment of material wound in a helical manner around an axis. The anchor shaft 306 and the myocardial engagement component 312 may be comprised of a material that has a stiffness that enables insertion into the myocardium with sufficient flexibility to allow deflection of the anchor shaft 306 and retraction of the myocardial engagement component 312, such as stainless steel and / or nickel-titanium alloy (e.g., Nitinol) and / or another suitable biocompatible alloy, and may have customized or variable stiffness and diameter along its length for increased pushability and kink resistance.

[0040] Further, the anchor system may include a flexible hinge mechanism 314 that allows the accessor catheter 304 to be torqued, angled, and / or pivoted as desired without displacing the anchor shaft 306. The hinge mechanism 314 is located at the proximal end of the myocardial engagement component 312 and distal end of the anchor shaft 306. The hinge mechanism 314 may comprise two semi-loops passing through each other, one permanently and rigidly connected to the anchor shaft 306, and the other one permanently and rigidly connected to the proximal end of the myocardial engagement component 312. In another example, the hinge mechanism 314 may comprise a spring, with one end of the spring permanently attached to the proximal end of the myocardial engagement component 312 and the other end tensioned around and permanently attached to the distal end of the anchor shaft 306. In a still further example, the hinge mechanism 314 may comprise a permanent attachment between the myocardial engagement component 312 and the anchor shaft 306. mechanically reducing the outer diameter of the joint section to allow mechanical flexibility for deflection. All of the above examples of the hinge mechanism 314 provide torquability and pushability while the myocardial engagement component 312 is contained within the accessor catheter 304, and flexibility and deflection while the myocardial engagement component 312 is deployed.

[0041] In some examples, the anchor system (comprising the anchor shaft 306, hinge mechanism 314, and myocardial engagement component 312) may be separate from the accessorAttorney Docket No. NIH24305PCT catheter 304, such that the anchor system can be inserted and removed from the accessor catheter 304 (e.g., for an “over-the-wire” configuration)., such as via a side port. In other examples, the anchor system may be integrated with the accessor catheter 304 (e.g.. unable to be fully removed from the accessor catheter 304) but still configured to move relative to the accessor catheter 304 along the x axis. The anchor system may have a length of 115-140 cm when the anchor system is not removable from the accessor catheter 304. The anchor system may have a length of 280-330 cm when the anchor system is removable from the accessor catheter 304.

[0042] FIG. 4 schematically shows the proximal / hub end of the ablation microcatheter 102 and navigation guidewire 110 as well as the hub end of the guiding catheter system 300. The ablation microcatheter 102 may terminate at a hub, which may include or be the hardware 112 of FIG. 1. The hardware 112 may facilitate coupling between elements of the ablation microcatheter 102 and electrode connectors and an RF connector, as explained above with respect to FIG. 1 . In FIG. 4, the hardware 112 is coupled to an RF connector 422, a positive electrode connector 424, and a negative electrode connector 426. It is to be appreciated that the ablation electrode 108 may be electrically coupled to the RF connector 422, and each of the first mapping electrode 104 and second mapping electrode 109 may be separately connected to each of the positive electrode connector 424 and negative electrode connector 426. The hub of the ablation microcatheter 102 may include an opening through which the navigation guidewire 110 extends. While not shown, the hardware 112 may further include a port for connecting to an irrigation pump, as explained above.

[0043] The guiding catheter system 300 includes a handle 400 at the proximal end. The handle 400 may include a body 401 with a first actuator 402 and a second actuator 404 for controlling the deflection angle and the pivot point location, respectively, of the outer catheter 302 and accessor catheter 304. In the example shown, the first actuator 402 may be a rotator knob and the second actuator 404 may be a slider knob, but other configurations are possible. The handle 400 further includes two entry lumens and one exit lumen for accommodating the anchor shaft 306 and the ablation microcatheter 102 (coaxially arranged with the navigation guidewire 110) and merging of the anchor shaft 306 and ablation microcatheter 102 into the accessor catheter 304. The two entry lumens may include a first entry lumen 406 configured to accommodate the ablation microcatheter 102 and a second entry lumen 408 configured to accommodate the anchor shaft 306. As shown, the anchor shaft 306 may terminate at the proximal end at a pusher 410 that may be moved alongAttorney Docket No. NIH24305PCT the x axis to move the anchor shaft 306 and deploy or retract the myocardial engagement component 312. The exit lumen 409 is present at the distal end of the handle 400. The outer catheter 302 extends outward from the distal end of the handle 400 and the accessor catheter 304 extends out of the handle 400 via the exit lumen 409, which is shown in FIG. 5 and explained in more detail below.

[0044] While not shown in FIG. 4, in some examples, the handle 400 may facilitate connection between the electrodes of the accessor catheter 304 and electrode connectors, similar to the hardware 112 and electrode connectors of the ablation catheter system, in order to connect the electrodes of the accessor catheter 304 to a signal processor. Further, in some examples, the myocardial engagement component 312 may be configured as electrodes for EAM and / or EDEN and the handle 400 may facilitate electrical connection between the myocardial engagement component and the signal processor. When the myocardial engagement component 312 is configured as an electrode(s) for EAM and / EDEN, the myocardial engagement component 312 may include one or more electrodes at one or more tips of the myocardial engagement component and / or one or more electrodes at mid-shaft of the myocardial engagement component (e.g., midshaft of one or more prongs or mid- shaft of the helix / corkscrew, depending on the configuration of the myocardial engagement component). For example, the myocardial engagement component may be insulated except at one or more regions (e.g., each prong may be insulated except at its tip or a mid-shaft portion).

[0045] FIG. 5 is a partially-transparent view of the handle 400 to enable visualization of the components in the interior of the handle 400. In the example shown in FIG. 5, the accessor catheter 304 extends through the interior of the handle 400, though and / or in proximity to the first actuator 402 and the second actuator 404, while the outer catheter 302 terminates at the handle 400. However, it is to be appreciated that the outer catheter 302 may extend into the handle 400 a suitable amount. The first actuator 402 may control the deflection angle of the outer catheter 302 and the second actuator 404 may control linear movement of the accessor catheter 304. By moving the accessor catheter 304 linearly within the outer catheter 302, the pivot point of the accessor catheter 304 may be adjusted.

[0046] Toward the proximal end of the handle 400, the accessor catheter 304 may terminate, and the anchor shaft 306 and ablation microcatheter 102 may extend from the second entry lumen 408 and the first entry lumen 406, respectively, to the terminating end of the accessor catheter 304,Attorney Docket No. NIH24305PCT where the anchor shaft 306 and the ablation microcatheter 102 may enter respective lumens of the accessor catheter 304. For example, as shown in FIG. 6, the accessor catheter 304 may have a terminating end 305 that includes two openings, with the anchor shaft 306 extending through a first opening of the two openings and the ablation microcatheter 102 extending through a second opening of the two openings. The first opening (and associated first lumen in the accessor catheter 304) may be larger than the outer diameter of the anchor shaft 306, which may allow for the myocardial engagement component 312 to fit inside the first lumen when in the retracted position. In some examples, the outer catheter 302 may not be coupled to the handle 400, but instead may be a separate deflectable catheter.

[0047] FIGS. 7-10 schematically show the flexible guiding catheter system 300 and ablation catheter system 100 positioned in a heart 700 of a patient in order to perform myocardial ablation. A portion of the heart 700 is shown in FIGS. 7-10, including a right ventricle 702 and a left ventricle 704 separated by myocardium (e.g., septum 706). FIG. 7 shows a zoomed-out perspective view in order to visualize both the distal ends and the proximal / hub ends of the guiding catheter system 300 and ablation catheter system 100. FIGS. 8 A and 8B show a front view of the portion of the heart 700 and the guiding catheter system 300 and ablation catheter system 100. FIGS. 9 and 10 show zoomed-in perspective views of the portion of the heart 700 and the guiding catheter system 300 and ablation catheter system 100. It is to be appreciated that the handle 400 and hardware 112 may remain outside the patient and that the anatomy surrounding the heart and providing access to the heart (e.g., the femoral vein) are not depicted in FIGS. 7-10 to enable visualization of certain aspects of the guiding catheter system 300 and ablation catheter system 100, such as the length of the outer catheter 302, that would otherwise be obscured.

[0048] As appreciated from FIG. 7, the distal ends of the guiding catheter system 300 and ablation catheter system 100 may be navigated to the right ventricle 702 (e.g., into the right ventricular cavity), with the outer catheter 302 (and coaxially-arranged accessor catheter 304 accommodating the anchor shaft 306, ablation microcatheter 102, and navigation guidewire 110) extending from the handle 400 to the heart 700 substantially along the x axis. However, the desired entry point into the myocardium in the example shown is the septum 706. Accordingly, a deflectable portion of the accessor catheter 304 or outer catheter 302 is adjusted (e.g., via the actuators on the handle 400) to form an approximately 90-degree bend at the distal end of theAttorney Docket No. NIH24305PCT accessor catheter 304, in order to position a final, distal segment of the accessor catheter 304 and associated components so that the distal segment extends substantially parallel to the y axis.

[0049] When the tip of the accessor catheter 304 is positioned along the myocardium at the desired entry point, the anchor shaft 306 may be extended relative to the accessor catheter 304 to embed the myocardial engagement component 312 within the myocardium, as shown in FIG. 8A. Once the anchor system is anchored at the desired location via the myocardial engagement component 312, the navigation guidewire 110 may be advanced into the myocardium and the ablation microcatheter 102 may track over the navigation guidewire 110, as shown in FIGS. 8 A and 8B. The position of the navigation guidewire 110 and ablation microcatheter 102 may be tracked using EAM, EDEN, fluoroscopy, and / or ICE. Once it is confirmed that the ablation microcatheter 102 is positioned at the ablation target, ablation may be performed via the ablation electrode (including irrigation of the ablation target to create and ablation field). It is to be appreciated that the navigation guidewire 110 may include a CTO-tip to allow the navigation guidewire 110, and hence ablation microcatheter 102, to be steered and advanced in a desired manner through the myocardium to allow for the curved trajectory shown in FIGS. 8 A and 8B.

[0050] FIGS. 9 and 10 show examples of deflection occurring via the outer catheter 302 and pivot point adjustment occurring via the accessor catheter 304. The outer catheter 302 has a constant length, a fixed pivot point, and an adjustable deflection radius. As shown in FIG. 9, the outer catheter 302 may include a deflectable portion 902 at the distal end of the outer catheter 302 (shown in blue in FIG. 9) that can be adjusted via the actuators of the handle 400 to change the deflection radius and / or deflection angle. For example, movement of the first actuator 402 to rotate the first actuator 402 clockwise or counter-clockwise may result in movement of a pull wire coupled to the deflectable portion 902 back toward the rear / proximal end of the handle 400. Movement of the pull wire may cause the deflectable portion 902 to bend with a desired radius of curvature, as shown. The accessor catheter 304 has a fixed length but is connected to second actuator 404 of the handle 400 so that the accessor catheter 304 can be moved linearly within the outer catheter 302. The second actuator 404 may be used to linearly move the accessor catheter 304 within the outer catheter 32 to change the pivot point of the accessor catheter 304, such that the distal tip of the accessor catheter 304 is positioned at a desired point along the z axis. FIG. 10 shows that the accessor catheter 304 has an adjustable extension length (shown in blue in FIG. 10) out of the outer catheter 302 to allow adjustment of the pivot point of the accessor catheter 304.Attorney Docket No. NIH24305PCT

[0051] The electrodes of the ablation microcatheter 102 shown in FIG. 2 as well as the electrodes of the accessor catheter 304 shown in FIG. 3 may be ring electrodes; however, other mapping electrode configurations are possible, such as partial rings that extend only partially around the respective shaft, strips, coils, etc. Further, the ring electrodes shown herein may have straight / flat edges that may be mounted on the ablation microcatheter 102 or accessor catheter 304 by bonding the edges of the electrodes to the material of the respective shaft using glue, heat, and / or other mechanisms, such as embedding the electrodes in the shaft by reflowing or extruding the shaft material segments before and after the electrodes. However, the straight edges of the electrodes may not adhere to the elements of the ablation microcatheter or accessor catheter as reliably as desired for all applications and may be prone to dislodging. Thus, one or more of the electrodes may include helical, feathered, dentate, and / or tapered extensions at the edges that allow enhanced bonding to the polymer components of the ablation microcatheter or accessor catheter and provide smoother mechanical transition from the polymer catheter shaft to the metal electrode body. The helical, feathered, dentate, and / or tapered extensions may be configured to be partially or fully embedded in the polymer segments of the ablation microcatheter and / or accessor catheter distal and proximal the electrodes.

[0052] Thus, an effector deliverable by an accessor is described herein. The effector may be configured to be navigated to a target within the myocardium and perform ablation within the myocardium. In the example disclosed herein, the effector may be the ablation catheter system described herein, which provides for coaxial arrangement of a 0.014" traversal and navigation guidewire (e.g., the navigation guidewire 110) and an -0.025" (typically 0.021-0.035") compatible tracking / infusion / ablation microcatheter (e.g., ablation microcatheter 102) with one or more mapping electrodes (e.g., the first mapping electrode 104 and the second mapping electrode 109) and a fenestrated / segmented ablation electrode (e.g., ablation electrode 108) having one or more openings. The ablation microcatheter may be low-profile, have a lumen for flowing irrigant and that tapers at a distal end to closely match the guidewire to deliver in coaxial fashion and to mitigate "size step-up" as the microcatheter is advanced over the coaxial guide wire, and have a braided metallic wire skeleton surrounded by electrically insulating and often lubricious polymer materials. Blood contacting surfaces of the microcatheter may be biocompatible. Polymers and / or markers of the microcatheter may be radiopaque to impart fluoroscopic conspicuity. The ablation microcatheter may incorporate electrical transmission lines that convey biopotentials, current,Attorney Docket No. NIH24305PCT ablative energy, or other electromagnetic signals to achieve ablation, biopotential measurement, and / or and electroanatomic tracking of the transmission line termini (e.g., the electrodes). The transmission lines may have shaped cross- sections. In particular, when a lining is provided that lines the ablation electrode, the electrical transmission lines may extend in the lining to electrically connect to elements distal of the ablation electrode (e.g., the first mapping electrode). In some examples, the polymer tube may include embedded metallic or non-metallic braiding or coils that are continuous or segmented to alter the mechanical performance of the ablation microcatheter. These braids or coils may include individually insulated metals that can serve as the transmission lines. The electrodes of the ablation microcatheter may be short (l-2mm) for tracking or longer (5- 10mm) for tracking and RF ablation. The ablation microcatheter may incorporate coils or braids to impart trackability and pushability and preservation of lumen dimensions during advancement along tortuous trajectories. The ablation microcatheter disclosed herein thereby incorporates irrigation opening(s) in an over-the-wire implementation, with an ablation electrode for intramyocardial ablation, tracking / mapping micro-coils / electrodes for E-field and B-field (electroanatomic) tracking, with a tapered nosecone configuration to allow delivery into the muscle of the beating heart.

[0053] The accessor may be included as part of the guiding catheter system described herein. The accessor (e.g., accessor catheter 304) may be configured to fit through a right ventricular angled delivery / guiding sheath (from the femoral vein to the right atrium makes a right angle into the right ventricle). The accessor may have one of three curve options to achieve orthogonal contact with the interventricular septum on the right ventricular side. The first option may be that the accessor has a fixed, 90-degree curve. The second option is that the accessor is deflectable from 0-135 degrees (or more) and has a variable radius of curvature. The third option is that the accessor may be a straight, flexible catheter contained within, and operated in combination with, a deflectable catheter having a deflection angle of 0-135 degrees and having a variable radius of curvature. The large radii allow the effector to rest against the right ventricular free wall to provide extra “backup support” while advancing equipment through the interventricular septum. The guiding catheter system may further include a deployable anchor system (e.g., the anchor shaft 306, myocardial engagement component 312, and hinge mechanism 314). The deployable anchor system may have a deployable myocardial engagement component, such as a set of anchor prongs having two or more sharp prongs that are configured to expand outward to engage the myocardiumAttorney Docket No. NIH24305PCT and prevent dislodgement. The anchor system may have a flexible hinge point mechanism that allows the accessor to be torqued, angled, and / or pivoted as desired to change the accessor endhole (e.g., the distal end of the accessor) entry angle without displacing the anchor shaft or changing the selected entry point. Once deployed, the anchor system allows the accessor tip contact position (where the distal end of the accessor contacts the myocardium) to be fixed. The anchor system may have an entry angle between 0 and 75-90 degrees relative to / orthogonal to the septal surface, and the myocardial engagement component (e.g., anchor prongs) may each extend until they are orthogonal to the accessor, typically 45-135 degrees. The guiding catheter system may include a mechanism to retrieve the anchor (e.g., the pusher) and the anchor system may optionally be configured with electrodes so that electrograms can be sampled from the anchor system as evidence of good contact.

[0054] The guiding catheter system may include a hub (e.g., handle 400) that controls the insertion / retraction of the anchor system, controls the deflection of the outer catheter, and controls the linear extension of the accessor. The hub may include or allow a hemostatic adapter valve for devices inserted / delivered through and into its endhole, and may include an optional side-hole for flushing.

[0055] The accessor may include non-concentric (e.g., side-by-side) accessor lumens to accommodate the anchor system and the effector. The accessor has an endhole through the second lumen to deliver the effector, appose it to the contact point, and provide backup support during advancement of the effector and accompanying navigation guidewire. The accessor may include one or more EAM tracking rings / coils (e.g., electrodes) to indicate position and orientation, including accompanying conductors and connectors. Optionally, the accessor may include radiopaque markers and / or enhanced ultrasound reflectance at least of the distal tip. The outer catheter may also include radiopaque markers to indicate the tip of the outer catheter.

[0056] It is to be appreciated that the effector may take on a different form than the ablation microcatheter disclosed herein. For example, rather than including fenestrations or other openings in the ablation electrode to facilitate irrigation, the ablation electrode may be continuous and lack apertures, and irrigation may occur due to the size mismatch between the navigation guidewire and the ablation microcatheter. In such examples, the ablation microcatheter may have a larger outer diameter (particularly at the distal tip) than the ablation microcatheter disclosed herein. AsAttorney Docket No. NIH24305PCT such, at least in some examples, the effector may include a dilator to facilitate embedding within the myocardium and / or may include a separate microcatheter to deliver the ablation microcatheter.

[0057] The ablation catheter system 100 and guiding catheter system 300 may be used to perform intramyocardial ablation according to the method 1100 of FIG. 11.

[0058] At 1102, method 1100 includes positioning and aiming the accessor (e.g., accessor catheter 304) and effector (e.g., ablation microcatheter 102) to the right ventricle using a curved or deflectable guiding sheath from a percutaneous venous access, such as the femoral vein into the right atrium, to the right ventricular septal endocardium (e.g., the endocardial surface of the septum). At 1104, the septum is engaged with the accessor, with the angle of engagement controlled if needed. To engage the septum with the accessor, the accessor or a fixed-curve or deflectable catheter (e.g., the outer catheter 302) may be adjusted to adjust a radius of curvature of the accessor to allow the distal end of the accessor to be positioned orthogonal to the septum. Further, if desired, the deflection angle may be adjusted to position the accessor at a desired entry point on the septum and / or at a desired entry angle. At 1106, the location of the accessor may be tracked and confirmed using EAM and / or EDEN based on signals obtained from the electrode(s) of the accessor and / or via fluoroscopy and / or intracardiac echocardiography.

[0059] Once the accessor is confirmed to be positioned at the interventricular septum, at a desired entry point and desired entry angle, the myocardial engagement component (e.g., the myocardial engagement component 312) of the anchor system may be inserted from the accessor into the myocardium, as indicated at 1108, and entry into the myocardium configured using EDEN unipolar electrogram morphology and classification. At 1110, method 1100 may include entering the myocardium with the navigation guidewire of the ablation catheter system, and at 1112, method 1100 includes entering and navigating the myocardium with the VINTAGE coaxial catheter-wire system (e.g., the ablation catheter system 100) using EDEN, EAM, fluoroscopy, and / or ultrasound. The ablation microcatheter and the navigation guidewire inside of the ablation microcatheter are delivered to the right ventricular septal endocardium via the accessor. The navigation guidewire is extended from this system to engage the myocardium. Electrosurgical radiofrequency energy may be used to traverse the endocardial border if needed. The ablation catheter system (e.g., the navigation guidewire 110 and the ablation microcatheter 102) is advanced to the deep intramyocardial ablation target. At 1114, mapping and pace-mapping may be performed as desired to localize the VT circuit to identify the ablation target. Thus, componentsAttorney Docket No. NIH24305PCT of the system may be used for determining functional characteristics of the target and nearby myocardium, for electroanatomic mapping of native and induced cardiac rhythms, and for ventricular stimulatory pulses to achieve pace-mapping of the target myocardium as appropriate. Multiple electrodes on the ablation microcatheter and navigation guidewire may be combined as desired for multipolar mapping.

[0060] At 1116, deep intramyocardial irrigation is performed. Once the ablation electrode (e.g., on the ablation microcatheter) is at the target, pre-irrigation is performed (e.g., with irrigant supplied via the lumen of the ablation microcatheter), typically with saline solution (0.45% - 0.9%), of the target ablation field via the fenestrations of the fenestrated ablation electrode of the ablation microcatheter, embedded deep in the myocardium adjoining the target, beginning approximately one minute before RF ablation is instituted, at a suitable rate, such as a rate of ~2mL / min, and continuing at the same rate until RF ablation is terminated. Irrigation may be performed with the navigation guidewire positioned in the ablation microcatheter and extending out from the distal tip of the ablation microcatheter, so that irrigant is forced out of the openings of the ablation electrode and is blocked from exiting the distal tip.

[0061] At 1118, method 1100 includes performing ablation including during irrigation. The ablation electrode (e.g., of the ablation microcatheter) is used to apply RF, pulsed field, or microwave energy to the target myocardium, typically / optionally continuously guided by real-time impedance monitoring. In some examples, the following empirically derived target thresholds may be applied for the RF energy application and real-time impedance monitoring: expected drop from irrigation 5 to 25 ohms; expected drop from heating 10 to 15 ohms; expected threshold increase heralding steam pop: 18 ohms. Ranges of RF energy include 10 to 50 W. RF energy may be altered during ablation based on the above-mentioned empirical parameters.

[0062] The ablation microcatheter may be repositioned and the mapping and ablation procedures repeated as needed, as indicated at 1120 of method 1100. At the conclusion of the procedure, the devices (e.g., the ablation microcatheter, the navigation guidewire, the anchor system myocardial engagement component) are removed from the myocardium, accessor and outer catheter withdrawn, hemostasis achieved, and the procedure concluded.

[0063] Thus, the VINTAGE system disclosed herein (e.g., the ablation catheter system 100) allows access to deep myocardial targets that are inaccessible for ablation from the endocardial and epicardial surfaces, including the deep septum, LV summit, and papillary muscles. TheAttorney Docket No. NIH24305PCT guiding catheter system disclosed herein (e.g., the guiding catheter system 300) may facilitate placement of the VINTAGE system at the endocardial border of the myocardium at a desired location and angle using an accessor housing the VINTAGE system that can be deflected directly or via a deflectable outer catheter. The guiding catheter system can provide backup support during intramyocardial entry and navigation using a deployable anchor system (e.g., that is deployed from the accessor) that has a flexible junction to allow the anchored accessor to change its entry position and angle to be varied interactively, a myocardial engagement component in its deployed position (e.g., the anchor prongs), and a retrieval mechanism upon procedure completion. The backup support may be further provided via variable radius of curvature of the accessor, which may allow the accessor distal tip to appose the contralateral endocameral wall during the procedure.

[0064] Some components of the VINTAGE system and the guiding catheter system (e.g., the ablation microcatheter, the navigation guidewire, and / or accessor) may include one or more electrodes to enable EAM in order to identify targets for ablation as well as enable EDEN to guide desired positioning of the components in the myocardium. In particular, real-time imaging techniques such as x-ray fluoroscopy or ultrasound may provide information regarding a longitudinal (e.g., base-to-apex) position and a circumferential (e.g., “clock-face”) position of the various components of the VINTAGE and guiding systems in the heart, these techniques lack information regarding a radial position (also termed radial depth) of the microcatheters / guidewires within the myocardium. As used herein with respect to the heart, the terms “radial position” and “radial depth” denote a relative position in a single dimension between the endocardial and epicardial surfaces of the heart. Using EDEN, the radial depth of an intracardiac device (such as the ablation microcatheter and / or the navigation guidewire, and if desired, the anchor prongs of the anchor guidewire) may be classified according to its relative position between the endocardial and epicardial borders (or beyond) via a depth navigation classifier (which may be a machine learning or deep learning-based algorithm or a logic-based algorithm) that uses intramyocardial electrograms measured by an electrode of the intracardiac device itself. Different depths between the endocardial and epicardial borders of the myocardium and outside of the myocardium produce different characteristic electrogram waveform features. These waveform features may be extracted and used by the classifier (executed on a signal processor, e.g., a computing device) to differentiate between different radial depth categories.Attorney Docket No. NIH24305PCT

[0065] In some examples, aspects of the VINTAGE system may be assembled into one or more kits as shown schematically in FIG. 12. A first kit 1200 may include a packaging 1202 housing the ablation microcatheter 102 (including the first mapping electrode 104, the ablation electrode 108, and the second mapping electrode 109, one or more or each or none of which may include helical, feathered, dentate, and / or tapered extensions) and the navigation guidewire 110 (including the exposed conductor 111). In some examples, the packaging 1202 may be sterile packaging. In some examples, each of the ablation microcatheter 102 and the navigation guidewire 110 may be packaged in individual, sterile packages, and the packaging 1202 may not be sterile. A second kit 1201 may include a packaging 1204 housing the accessor catheter 304 (optionally including the first electrode 308 and the second electrode 310, one or more or each or none of which may include helical, feathered, dentate, and / or tapered extensions) and the anchor system (including the anchor shaft 306, the myocardial engagement component 312, and hinge mechanism 314), either as separate components or with the anchor system integrated in the accessor catheter 304. In some examples, the packaging 1204 may be sterile packaging. In some examples, each of the accessor catheter 304 and the anchor system may be packaged in individual, sterile packages, and the packaging 1204 may not be sterile.

[0066] In some examples, the second kit 1201 may include the outer catheter 302. Further, in some examples, the first kit 1200 and / or the second kit 1201 may include one or more electrode connectors 1206.

[0067] When the one or more electrode connectors 1206 are included in the first kit 1200, the one or more electrode connectors 1206 may be included in packaging 1202. In still further examples, the first kit 1200 may include connectors, signal wires, and / or other components for connecting the ablation microcatheter and the navigation guidewire to an EAM and / or EDEN signal processor and / or for connecting the ablation microcatheter to the RF generator. When the outer catheter 302 and / or the one or more electrode connectors 1206 are included in the second kit 1201, the outer catheter 302 and / or the one or more electrode connectors 1206 may be included in packaging 1204 (and in some examples, at least the outer catheter 302 may be packaged in individual or common sterile packaging). In still further examples, the second kit 1201 may include connectors, signal wires, and / or other components for connecting the accessor catheter and / or the anchor guidewire to an EAM and / or EDEN signal processor.Attorney Docket No. NIH24305PCT

[0068] In some examples, the first kit 1200 may include multiple ablation microcatheters and navigation guidewires, such as 5, 10, 25, 50, 100, or more of each of the ablation microcatheter and the navigation guidewire. In such examples, each individual component (e.g., each ablation microcatheter, each navigation guidewire) may be packaged in a separate sterile packaging and all housed within packaging 1202. Alternatively, one of each of the ablation microcatheter and the navigation guidewire may be packaged together in a common, sterile packaging to form a sub-kit, and a plurality of sub-kits (e.g., 5, 10, 25, 50, 100, etc.) may be packaged in packaging 1202. In examples where the first kit 1200 includes the one or more electrode connectors 1206, the first kit 1200 may include multiple sets of the one or more electrode connectors 1206, packaged similarly to the ablation microcatheters and navigation guidewires (e.g., individually or in sub-kits).

[0069] In some examples, the second kit 1201 may include multiple accessor catheters and anchor systems, such as 5, 10, 25, 50, 100, or more of each of the accessor catheter and the anchor system. In such examples, each individual component (e.g., each accessor catheter, each anchor system) may be packaged in a separate sterile packaging and all housed within packaging 1204. Alternatively, one of each of the accessor catheter and the anchor system may be packaged together in a common, sterile packaging to form a sub-kit, and a plurality of sub-kits (e.g., 5, 10, 25, 50, 100, etc.) may be packaged in packaging 1204. In examples where the second kit 1201 includes the outer catheter 302 and / or the one or more electrode connectors 1206, the second kit 1201 may include multiple outer catheters and / or multiple sets of the one or more electrode connectors 1206, packaged similarly to the accessor catheters and anchor guidewires (e.g., individually or in subkits).

[0070] In some examples, the first kit 1200 and the second kit 1201 may be combined into one overall kit. In such examples, each component (e.g., the ablation microcatheter, navigation guidewire, accessor catheter, anchor system, and optionally the outer catheter and / or one or more electrode connectors) may be packaged in a common sterile packaging. In other examples, each individual component may be packaged in a separate sterile packaging and all housed in a common packaging. In still further examples, the overall kit may include multiples of each component (e.g., multiple ablation microcatheters, navigation guidewires, accessor catheters, and anchor systems, and optionally multiple outer catheters and / or multiple sets of electrode connectors, such as 5, 10, 25, 50, 100, or more of each of the ablation microcatheter, the navigation guidewire, the accessor catheter, and the anchor system and optionally the outer catheter and / or electrode connectors),Attorney Docket No. NIH24305PCT packaged individually in separate sterile packaging or packaged into sub-kit, where each sub-kit includes components for performing one VINTAGE procedure (e.g., an ablation microcatheter, a navigation guidewire, an accessor catheter, an anchor system, and optionally an outer catheter and / or one or more electrode connectors).

[0071] Thus, intramyocardial procedures, such as current ablation therapy for VT, a common and life-threatening disease, are hampered by the relative inaccessibility of deep intramural myocardial targets. For example, arrhythmias originating from deep or anatomically inaccessible locations are hard to reach and treat by currently available technologies, accounting for a high rate of arrhythmia recurrence. The VINTAGE system disclosed herein addresses these issues by providing for ablation electrode navigation inside the beating ventricle and ablation inside the muscle, rather than from endocardial or epicardial surfaces, via delivery of RF energy using the ablation electrode of the ablation microcatheter inside the myocardium and intramyocardial irrigation inside the myocardium prior to and during ablation. The problem of ventricular arrhythmia critical circuit elements inaccessible to conventional endocardial or epicardial radiofrequency ablation is solved with the VINTAGE system by deep intramyocardial ablation electrode access and positioning combined with intramyocardial infiltrative irrigation through the fenestrations of the ablation electrode. The problem of navigating and positioning such deep intramyocardial ablation electrodes is solved with the VINTAGE system by adding elements, for EDEN and for electroanatomic mapping and for multipolar intramyocardial pacing and mapping, to microcatheters and guidewires, which allows visualization and / or depth determination of the microcatheters and guidewires in tandem and relative to each other. The problem of insufficiently large ablation fields is solved with the VINTAGE system by deep intramyocardial infiltration by an intramyocardial infusion and ablation microcatheter larger than, and surrounding, the navigation guidewire. The ablation microcatheter may incorporate multiple features (e.g., fenestrated / segmented irrigation-ablation electrode and electromagnetic tracking and multipolar sensing / pacing elements) into a single over-the-wire catheter. The problem of mostly-orthogonal contact with the right ventricular septal endocardium is solved with the accessor catheter that can accomplish multiple shapes interactively. The problem of inadequate backup support during myocardial entry and navigation is solved with the deployable anchor system and variable radius of curvature of the accessor catheter to provide counter-traction during intramyocardial guidewire / catheter advancement.Attorney Docket No. NIH24305PCT

[0072] Thus, a guiding system for positioning an over-the-wire microcatheter is disclosed herein. The over-the-wire microcatheter may include an ablation electrode having one or more openings to allow intramyocardial irrigation; at least two electrodes for intramyocardial unipolar or multipolar mapping, pacing, and registration with electroanatomic mapping; and a tapered distal end to allow delivery into the myocardium over a wire. The guiding system may include an accessor catheter with one or more lumens to accommodate the over-the-wire microcatheter and an anchor system. The accessor catheter may be deflectable or housed in a deflectable outer catheter optionally and may optionally include at least two electrodes for electroanatomic mapping.

[0073] Characteristics of the ablation microcatheter and / or accessor catheter include biocompatibility and hemocompatibility, hydrophilic material that allows tracking over a wire as well as flexibility, a Luer-Lock connector at the proximal hub to allow irrigation with pressurized fluid, and connections to the electroanatomic mapping system and / or ablation generator.

[0074] The ablation microcatheter may have the following characteristics: an outer diameter of 0.025-0.038"; an inner diameter 0.021-0.035" to accommodate an 0.014" guidewire and intramyocardial irrigation through the fenestrations; a tapered tip to an inner diameter of 0.014- 0.018" at the distal opening to track over the guidewire; a fenestrated ablation electrode that is 10- 15 mm in length; at least two electrodes (one on either side of the ablation electrode) that are 1-2 mm in length; and a usable length ranging between 135-175 cm. The ablation microcatheter may optionally include longitudinal grooves inside the central lumen to enhance irrigation fluid delivery.

[0075] The accessor catheter may have the following characteristics: outer diameter approximately 6-8.3 F; usable length 110-135 cm; has an end hole typically having two lumens, one for the delivery of the anchor system and another one for the effector (ablation microcatheter); the deployable anchor system having, in at least one example, three or more sharp prongs -10-15 mm in length; and optionally has at least one distal electrode for registration with electroanatomic mapping. The accessor catheter may have deflectable capabilities with a distal deflectable portion that has a radius of 2-5 cm and deflection angle 0-135 degrees. An alternative design is that the accessor catheter may have a fixed 90-degree distal deflection. A further alternative design is that the accessor catheter is contained within a deflectable catheter with the following characteristics: outer diameter 8-8.5 F; usable length 100-130 cm; distal end hole for the accessor catheter to exit;Attorney Docket No. NIH24305PCT distal deflectable portion with variable radius of deflection 2-5 cm and deflection angle 0-135 degrees. The guiding system may include a proximal handle to control radius and angle of deflection, loading, and manipulation of the accessor catheter, and loading and manipulation of the effector (e.g., ablation microcatheter). The deflectable catheter may be delivered over an 0.035” guidewire or a dilator.

[0076] A method for VINTAGE using the herein described microcatheter use may include: percutaneous access to the femoral vein; use of a commercially available deflectable sheath to get into the right ventricle through the tricuspid valve; engagement of the right ventricular septum using the accessor catheter, the angle of engagement is controlled by either deflectable characteristics of the accessor catheter or the deflectable outer catheter; the accessor catheter is registered within the EAM and / or EDEN to confinn location; release of the myocardial engagement component of the anchor system in the myocardium for support and counter-traction; right ventricular septum entry through the second lumen of the accessor catheter, using a stiff 0.014” guidewire housed inside the effector; navigation of the 0.014” guidewire within the myocardium in tandem with the VINTAGE effector; once at target, intramyocardial irrigation and ablation is performed through the fenestrated / segmented ablation electrode.

[0077] Optionally, the electrodes (of the ablation microcatheter and / or accessor catheter) may have helical, feathered, dentate, and / or tapered tails / extensions to ease bonding to the catheter shaft during manufacturing and thereby reduce risk of dislodgement / embolization. Additionally, the fenestrations may not be circular and / or the fenestrations may be distributed to allow the electrode to be oriented to effect infiltration asymmetrically towards intended targets and thereby creating an asymmetric ablation field. Materials options include molybdenum-rhenium allows lower profile.

[0078] FIGS. 1-10 show example configurations with relative positioning of the various components. If shown directly contacting each other, or directly coupled, then such elements may be referred to as directly contacting or directly coupled, respectively, at least in one example. Similarly, elements shown contiguous or adjacent to one another may be contiguous or adjacent to each other, respectively, at least in one example. As an example, components laying in facesharing contact with each other may be referred to as in face-sharing contact. As another example, elements positioned apart from each other with only a space there-between and no other components may be referred to as such, in at least one example. As yet another example, elementsAttorney Docket No. NIH24305PCT shown above / below one another, at opposite sides to one another, or to the left / right of one another may be referred to as such, relative to one another. Further, as shown in the figures, a topmost element or point of element may be referred to as a “top” of the component and a bottommost element or point of the element may be referred to as a “bottom” of the component, in at least one example. As used herein, top / bottom, upper / lower, above / below, may be relative to a vertical axis of the figures and used to describe positioning of elements of the figures relative to one another. As such, elements shown above other elements are positioned vertically above the other elements, in one example. As yet another example, shapes of the elements depicted within the figures may be referred to as having those shapes (e.g„ such as being circular, straight, planar, curved, rounded, chamfered, angled, or the like). Further, elements shown intersecting one another may be referred to as intersecting elements or intersecting one another, in at least one example. Further still, an element shown within another element or shown outside of another element may be referred as such, in one example.

[0079] The disclosure also provides support for a guiding catheter system for intramyocardial navigation and ablation, comprising: an accessor catheter including a shaft, the shaft including one or more lumens, the one or more lumens sized to accommodate an effector configured to perform intramyocardial navigation and an anchor system. In a first example of the system, the system further comprises: one or more mapping electrodes coupled to the shaft at and / or near a distal tip of the shaft. In a second example of the system, optionally including the first example, the shaft includes a bend near a distal tip of the shaft. In a third example of the system, optionally including one or both of the first and second examples, the shaft includes a deflectable portion near a distal tip of the shaft and configured to adjust a radius of curvature of the shaft. In a fourth example of the system, optionally including one or more or each of the first through third examples, the system further comprises: an outer catheter having an adjustable deflection radius, the accessor catheter coaxially arranged in the outer catheter. In a fifth example of the system, optionally including one or more or each of the first through fourth examples, the system further comprises: a handle coupled to the shaft and the outer catheter at a proximal end of the shaft and the outer catheter, the handle including a first actuator and a second actuator, the first actuator configured to adjust the deflection radius of the outer catheter and the second actuator configured to adjust a linear position of the shaft relative to the outer catheter. In a sixth example of the system, optionally including one or more or each of the first through fifth examples, the anchor system comprises an anchorAttorney Docket No. NIH24305PCT shaft coupled to a myocardial engagement component. In a seventh example of the system, optionally including one or more or each of the first through sixth examples, the myocardial engagement component comprises a set of anchor prongs or a helical anchor. In an eighth example of the system, optionally including one or more or each of the first through seventh examples, the anchor shaft is coupled to the myocardial engagement component via a hinge mechanism. In a ninth example of the system, optionally including one or more or each of the first through eighth examples, the one or more lumens of the shaft include two non-concentric lumens, the two non- concentric lumens including a first lumen to accommodate the effector and a second lumen to accommodate the anchor system.

[0080] This disclosure also provides support for a kit including the accessor catheter of the guiding catheter system above, optionally the accessor catheter of one or more or each of the first through ninth examples, and the anchor system. In first example of the kit, the kit further comprises: the effector, wherein the effector comprises an ablation microcatheter including an ablation electrode, the ablation electrode including one or more openings. In a second example of the kit, optionally including the first example, the kit further comprises: a navigation guidewire, wherein the navigation guidewire is configured to be slidingly received by an inner lumen of the ablation microcatheter. In a third example of the kit, optionally including one or more or each of the first and second examples, the ablation microcatheter includes an irrigation port and a radiofrequency (RF) connector.

[0081] The disclosure also provides support for a method for an ablation procedure, comprising: navigating an effector to an entry point on a myocardial surface with an accessor catheter, deploying a myocardial engagement component of an anchor system from the accessor catheter into myocardium at the entry point, extending the effector out of the accessor catheter and to an ablation target in the myocardium, and ablating the ablation target with radiofrequency (RF), pulsed field, or microwave energy via the effector. In a first example of the method, navigating the effector to the entry point on the myocardial surface with the accessor catheter comprises adjusting a deflection angle and / or radius of curvature and / or pivot point of the accessor catheter to position at a distal tip of the accessor catheter orthogonal to the myocardial surface. In a second example of the method, optionally including the first example, navigating the effector to the entry point on the myocardial surface with the accessor catheter comprises navigating the effector to the entry point based on electromagnetic fields encoding spatial position and time from anAttorney Docket No. NIH24305PCT electroanatomic mapping system detected by one or more electrodes positioned on the accessor catheter. In a third example of the method, optionally including one or both of the first and second examples, the effector includes an ablation microcatheter comprising a conductive ablation electrode having one or more openings, and wherein ablating the ablation target includes irrigating the ablation target with an electrolyte via the one or more openings. In a fourth example of the method, optionally including one or more or each of the first through third examples, the method further comprises: navigating the ablation microcatheter to the ablation target based on electrograms generated by one or more electrodes positioned on the ablation microcatheter. In a fifth example of the method, optionally including one or more or each of the first through fourth examples, ablating the ablation target with RF, pulsed field, or microwave energy via the effector comprises activating an RF generator coupled to the conductive ablation electrode.

[0082] As used herein, an element or step recited in the singular and preceded with the word “a” or “an” should be understood as not excluding plural of said elements or steps, unless such exclusion is explicitly stated. Furthermore, references to “one embodiment” of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments “comprising,” “including,” or “having” an element or a plurality of elements having a particular property may include additional such elements not having that property. The terms “including” and “in which” are used as the plain-language equivalents of the respective terms “comprising” and “wherein.” Moreover, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements or a particular positional order on their objects.

[0083] This written description uses examples to disclose the invention, including the best mode, and also to enable a person of ordinary skill in the relevant art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those of ordinary skill in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

Attorney Docket No. NIH24305PCTCLAIMS:

1. A guiding catheter system for intramyocardial navigation and ablation, comprising: an accessor catheter including a shaft, the shaft including one or more lumens, the one or more lumens sized to accommodate an effector configured to perform intramyocardial navigation and an anchor system.

2. The guiding catheter system of claim 1 , further comprising one or more mapping electrodes coupled to the shaft at and / or near a distal tip of the shaft.

3. The guiding catheter system of claim 1 or 2, wherein the shaft includes a bend near a distal tip of the shaft.

4. The guiding catheter system of claim 1 or 2, wherein the shaft includes a deflectable portion near a distal tip of the shaft and configured to adjust a radius of curvature of the shaft.

5. The guiding catheter system of claim 1 or 2, further comprising an outer catheter having an adjustable deflection radius, the accessor catheter coaxially arranged in the outer catheter.

6. The guiding catheter system of claim 5, further comprising a handle coupled to the shaft and the outer catheter at a proximal end of the shaft and the outer catheter, the handle including a first actuator and a second actuator, the first actuator configured to adjust the deflection radius of the outer catheter and the second actuator configured to adjust a linear position of the shaft relative to the outer catheter.

7. The guiding catheter system of any one of claims 1 -6, wherein the anchor system comprises an anchor shaft coupled to a myocardial engagement component.

8. The guiding catheter system of claim 7, wherein the myocardial engagement component comprises a set of anchor prongs or a helical anchor.Attorney Docket No. NIH24305PCT9. The guiding catheter system of claim 7 or 8, wherein the anchor shaft is coupled to the myocardial engagement component via a hinge mechanism.

10. The guiding catheter system of any one of claims 1-9, wherein the one or more lumens of the shaft include two non-concentric lumens, the two non-concentric lumens including a first lumen to accommodate the effector and a second lumen to accommodate the anchor system.

11. A kit for intramyocardial navigation and ablation, comprising: the accessor catheter of claim 1; and the anchor system.

12. The kit of claim 11 , further comprising the effector, wherein the effector comprises an ablation microcatheter including an ablation electrode, the ablation electrode including one or more openings.

13. The kit of claim 12, further comprising a navigation guidewire, wherein the navigation guidewire is configured to be slidingly received by an inner lumen of the ablation microcatheter.

14. The kit of claim 12 or 13, wherein the ablation microcatheter includes an irrigation port and a radiofrequency (RF) connector.

15. A method for an ablation procedure, comprising: navigating an effector to an entry point on a myocardial surface with an accessor catheter; deploying a myocardial engagement component of an anchor system from the accessor catheter into myocardium at the entry point; extending the effector out of the accessor catheter and to an ablation target in the myocardium; and ablating the ablation target with radiofrequency (RF), pulsed field, or microwave energy via the effector.Attorney Docket No. NIH24305PCT16. The method of claim 15, wherein navigating the effector to the entry point on the myocardial surface with the accessor catheter comprises adjusting a deflection angle and / or radius of curvature and / or pivot point of the accessor catheter to position at a distal tip of the accessor catheter orthogonal to the myocardial surface.

17. The method of claim 15 or 16, wherein navigating the effector to the entry point on the myocardial surface with the accessor catheter comprises navigating the effector to the entry point based on electromagnetic fields encoding spatial position and time from an electroanatomic mapping system detected by one or more electrodes positioned on the accessor catheter.

18. The method of any one of claims 15-17, wherein the effector includes an ablation microcatheter comprising a conductive ablation electrode having one or more openings, and wherein ablating the ablation target includes irrigating the ablation target with an electrolyte via the one or more openings.

19. The method of claim 18, further comprising navigating the ablation microcatheter to the ablation target based on electrograms generated by one or more electrodes positioned on the ablation microcatheter.

20. The method of claim 18 or 19, wherein ablating the ablation target with RF, pulsed field, or microwave energy via the effector comprises activating an RF generator coupled to the conductive ablation electrode.

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