Apparatus and method for piercing tissue - Patents.com

Abstract

To improve safety of a treatment for puncturing a target tissue.SOLUTION: A method and apparatus are disclosed for puncturing a target tissue. The apparatus includes an elongate puncture device having a tip electrode that is configured for collecting EGMS and for delivering energy for puncturing the target tissue. The method comprises collecting EGMS to indirectly measure and monitor a pressure applied against the target tissue by the elongate puncture device, thereby confirming a position of the tip electrode of the elongate puncture device relative to the target tissue.SELECTED DRAWING: Figure 17

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to systems and methods for delivering energy to tissue, and more particularly, to delivering energy using an electrosurgical device to penetrate tissue. Summary of the Invention

[0002] A method for verifying the location of a tip of a puncture device relative to a target tissue can be used to enhance the safety of a procedure for puncturing a target tissue with a puncture device. The method includes using an elongated device (e.g., a radiofrequency (RF) guidewire) having a tip electrode configured to collect electrograms (EGMs) and deliver electrical energy to puncture the tissue, the method including collecting EGMs to indirectly measure and monitor pressure exerted by the elongated device against the target tissue, thereby indicating tip location relative to the target tissue. In some embodiments, the target tissue is on the pericardium, and the method includes collecting epicardial electrograms (EGMs) to measure and monitor pressure exerted against a pericardial target tissue site. In other embodiments, the tissue is a part of the body other than the pericardium, for example, the septum of the heart.

[0003] In a first broad aspect, an embodiment of the invention includes a method of ascertaining a position of a tip of a puncture device relative to a target tissue, the method including using an elongate puncture device having a tip electrode configured to acquire EGMs and deliver energy to puncture the tissue, the method including acquiring EGMs with the tip electrode and measuring and monitoring pressure exerted by the tip electrode of the elongate puncture device against the target tissue.

[0004] In some embodiments of the first broad aspect, the target tissue is the pericardium. In some other embodiments, the target tissue is the cardiac septum, and in some such embodiments, the target tissue is the atrial septum. In some examples of the first broad aspect, the elongated puncture device delivers radiofrequency energy, and in some such examples, the elongated puncture device is a radiofrequency guidewire, or a radiofrequency stylet, or a radiofrequency trocar. In some examples, the EGM is collected from the pericardium, and in some other examples, the EGM is collected from the cardiac septum. In some embodiments, the elongated puncture device applies pressure against the pericardial tissue, and in other embodiments, the elongated puncture device applies pressure against the cardiac septum.

[0005] In a second broad aspect, an embodiment of the invention includes a method of puncturing a target tissue comprising using an elongate puncturing device having a tip electrode configured to collect EGMs and deliver energy to puncture the target tissue, the method including collecting EGMs and measuring and monitoring pressure exerted by the elongate puncturing device against the target tissue, thereby verifying the position of the tip electrode of the elongate puncturing device relative to the target tissue.

[0006] In some embodiments of the second broad aspect, the target tissue is the pericardium. In other embodiments, the target tissue is the cardiac septum, and in some such embodiments, the target tissue is the atrial septum. In some examples of the second broad aspect, the elongated puncture device delivers radiofrequency energy, and in some such examples, the elongated puncture device is a radiofrequency guidewire. In some examples of the second broad aspect, the EGM is collected from the pericardium, and in some other examples, the EGM is collected from the cardiac septum. In some embodiments of the second broad aspect, the elongated puncture device applies pressure against the pericardial tissue, and in other embodiments, the elongated puncture device applies pressure against the cardiac septum.

[0007] In a third broad aspect, an embodiment of the invention is a method of gaining access to the pericardial cavity, comprising the steps of: (a) introducing a blunt stylet into an introducer; (b) advancing the combined blunt stylet and introducer through adipose tissue toward pericardial tissue; (c) removing the stylet from the introducer; (d) placing a flexible elongated puncture device within the introducer; and (e) advancing a tip of the elongated puncture device distal to the introducer under fluoroscopic guidance, thereby introducing an electrode of the elongated puncture device into any parenchymal tissue. (f) monitoring the EGM based on electrodes of the elongated puncture device in contact with the pericardium to confirm the presence of a low ST segment; (g) exerting force using electrodes of the introducer and guidewire to tent the pericardium; (h) monitoring the EGM to confirm that the wave is higher than the wave of step (f); (i) delivering energy to tissue of the pericardium through the electrodes; and (j) monitoring the EGM to confirm that the ST segment is higher than the waves of steps (f) and (h).

[0008] In exemplary embodiments of the third broad aspect, step (i) includes delivering a short pulse of high voltage AC. In some such embodiments, the short pulse is ⅓ second. Exemplary embodiments further include a step (k) of advancing a distal portion of the introducer into the pericardial space and monitoring the EGM.

[0009] In some embodiments of the third broad aspect, steps (e) and (f) occur simultaneously. In some embodiments, steps (g) and (h) occur simultaneously. In some embodiments, steps (i) and (j) occur simultaneously.

[0010] Some embodiments of the third broad aspect further include a step (l) of delivering contrast media. Some embodiments further include a step (m) of withdrawing fluid from the pericardial space. Some embodiments further include a step (n) of advancing an elongate puncture device into the pericardial cavity. Some embodiments further include a step (o) of confirming access by wrapping a guidewire at least once around the heart and visualizing under fluoroscopy.

[0011] In a fourth broad aspect, an embodiment of the invention is a method of puncturing a target tissue to gain access to the pericardial cavity, comprising the steps of: (1) connecting an electrically insulated wire having one distal pole to a recording system having an electrocardiogram reference to a patient; (2) puncturing the patient's skin via a subxiphoid, parasternal intercostal or apical approach with a rigid introducer and an engaging stylet; and (3) introducing the rigid introducer through various dermal layers toward the pericardial sac of the heart under the guidance of fluoroscopy and tactile feedback. (3) advancing the introducer and stylet to position the tip of the introducer near the pericardial sac; (4) removing the stylet and placing an elongated puncture device within the introducer while the radially blunt end of the introducer is docked with the pericardial sac; (5) advancing the elongated puncture device while the introducer is in contact with the outside of the pericardial sac; and (6) delivering energy to the pericardial sac through an electrode at the tip of the elongated puncture device.

[0012] In exemplary embodiments of the fourth broad aspect, step (5) includes recording local epicardial EGMs from an electrode tip of an elongated puncture device. In some such embodiments, step (5) further includes monitoring the EGMs to verify that waveform amplitude increases with higher mechanical forces on the heart.

[0013] In some embodiments of the fourth broad aspect, step (6) includes the energy being delivered as at least one pulse. In some other embodiments of the fourth broad aspect, step (6) includes the energy being delivered as a series of pulses starting at a low pressure level to the pericardial sac in the first repetition to avoid overshoot, and the amount of pressure exerted on the pericardial sac is increased with each repetition while maintaining the same pulse time and energy level. In some embodiments, step (6) includes checking whether the pericardial sac has been punctured and access to the pericardial cavity has been gained.

[0014] Exemplary embodiments of the fourth broad aspect further include the step of monitoring (7) electrical activity of the epicardial surface using an electrode at the distal tip of the elongated puncture device (after RF puncture of the pericardial sac provides access to the pericardial space). Some embodiments further include the step of (8) further deploying the elongated puncture device into the pericardial space to relieve pressure at the tip and induce a change in the EGM trace. Some embodiments further include the step of (9) deploying a guidewire to track along the epicardial surface of the heart while collecting local epicardial EGMs. Some embodiments further include the step of advancing a sheath and dilator over the elongated puncture device.

[0015] In a fifth broad aspect, embodiments of the invention include a method of ascertaining the position of a tip of an elongated puncture device relative to an introducer, where the elongated puncture device has a proximal marker visible to the naked eye and a distal tip marker visible under an imaging system, and the introducer has a distal end marker visible under the imaging system. The method includes: (1) positioning the elongated puncture device relative to the proximal end of the introducer using the proximal marker without the imaging system in a macropositioning step; (2) turning on the imaging system; and (3) positioning the distal tip of the elongated puncture device relative to the end of the introducer by viewing the distal tip marker and the distal end marker using the imaging system in a micropositioning step. In some such embodiments, the imaging system is a fluoroscopy system, and the distal tip marker and the distal end marker are visible under fluoroscopy.

[0016] In some embodiments of the first, second, third, fourth, and fifth broad aspects, the elongate puncture device includes a radiofrequency guidewire.

[0017] In a sixth broad aspect, an embodiment of the invention includes an elongate puncture device including a mandrel that is conductive and covered by a transparent insulating layer, the transparent layer preventing shorting of a distal end of the mandrel such that a distal end of the mandrel is electrically exposed to define a distal tip electrode, a portion of the mandrel is surrounded by a visible marker, the visible marker is covered by the transparent layer, and a portion of the elongate puncture device adjacent to the visible marker at the visible marker has a constant outer diameter.

[0018] In an exemplary embodiment of the sixth broad aspect, a mandrel is surrounded by an oxide coating covered by a transparent insulating layer, and the oxide coating is removed from at least a portion of the mandrel such that the at least one portion defines at least one visible marker.

[0019] In some embodiments of the sixth broad aspect, the at least one visible marker comprises at least a portion of the mandrel, and the oxide coating is in contact with the mandrel. In some such embodiments, the oxide coating is comprised of a layer of titanium dioxide. Embodiments include where the visible marker may be a proximal marker, a middle marker, or a distal marker. In an exemplary embodiment, the transparent layer comprises a heat shrink layer, and in some such embodiments, the heat shrink layer comprises a polytetrafluoroethylene material.

[0020] In some embodiments of the sixth broad aspect, the mandrel is constructed of Nitinol. In some other embodiments, the mandrel is constructed of stainless steel. In an exemplary embodiment, the elongate puncture device is flexible.

[0021] In exemplary embodiments of the sixth broad aspect, the mandrel is electrically conductive, a proximal end portion of the mandrel is not insulated, and the distal tip electrode is operable to connect to a power source such that the distal tip electrode is in electrical communication with the power source, energy can be delivered to tissue through the distal tip electrode, and the distal tip electrode enables the epicardial EGMs to be recorded. Such embodiments typically have an elongated puncture device shaft that is electrically insulated to reduce noise from any collected local EGMs. In some embodiments, the distal tip electrode has an outer diameter >.027 inches (0.686 mm) and a length of about 1.8 to about 2.4 mm. 2 The device has a hemispherical dome having a surface area of

[0022] Exemplary embodiments of the sixth broad aspect further include a distal end portion having a J-profile. Such embodiments typically further include a radiopaque coil extending around the curve of the distal end portion having a J-profile. In such embodiments, the end of the radiopaque coil may be used as a distal tip marker. In some examples, the radiopaque coil has echogenic properties when using ultrasound to enable visualization of the guidewire tip.

[0023] In some embodiments of the sixth broad definition, the elongate puncture device includes a radiofrequency guidewire.

[0024] In a seventh broad aspect, embodiments of the invention include an introducer for use with an elongate puncture device, the introducer including an introducer shaft connected to a hub, the introducer shaft including an inner metal tube interposed between two insulating layers with the ends of the two layers joined together to adhere the layers. In an exemplary embodiment, the two insulating layers are constructed of high density polyethylene. In some embodiments, the hub further includes a male port for connecting to the tubing and a receiving opening for receiving a stylet or wire, whereby the hub is operable to be simultaneously attached to a fluid source while a stylet or wire is inserted into the hub.

[0025] In an eighth broad aspect, an embodiment of the invention includes a kit including an introducer and an elongated puncture device, the elongated puncture device including a distal tip electrode that allows for recording of epicardial EGMs, the shaft of the elongated puncture device being electrically insulated to reduce noise in any collected local EGMs, the introducer including an introducer shaft connected to a hub, the introducer shaft including an inner metal tube interposed between two electrically insulating layers with both ends of the two layers joined together to bond the layers, to reduce noise in any EGMs collected by the elongated puncture device. In an exemplary embodiment of the eighth broad aspect, the introducer and the elongated puncture device are configured such that the introducer has the ability to deliver and withdraw fluids while the elongated puncture device is inserted therethrough. In some examples, the radial gap between the inner diameter of the tip of the introducer and the outer diameter of the elongated puncture device is >0.025 mm (.001 inch). In some such embodiments, the kit is operable to provide a contrast flow of >15 ml / min at 10 PSI. In some embodiments, the inner diameter of the introducer tip is .0385 inches + / - .0005 inches and the maximum outer diameter of the elongated puncture device is .0350 inches + / - .0005 inches, such that the minimum clearance for this geometry is .00125 inches.

[0026] Some embodiments of the eighth broad aspect further include a stylet, the cross-section of which varies along the length of the stylet and tapers downwardly toward the distal tip of the stylet to allow for fluid flow through the tip of the introducer when the stylet is placed. Some embodiments further comprise a stylet, the stylet being electrically insulated and operable to be connected to a recording system to facilitate collecting EGM information useful for positioning the tip of the introducer as it approaches the heart.

[0027] Some embodiments of the eighth broad aspect further include markers for positioning the elongate puncture device relative to the introducer, where the elongate puncture device has a proximal marker visible to the naked eye and a distal tip marker visible under an imaging system, and the introducer has a distal end marker visible under the imaging system. In typical embodiments, the distal tip marker and the distal end marker are visible under fluoroscopy.

[0028] In some embodiments of the eighth broad aspect, when the proximal marker of the elongate puncture device is positioned at the proximal end of the introducer hub, the tip of the elongate puncture device extends distally of the shaft of the introducer shaft. In some other embodiments of the eighth broad aspect, when the proximal marker of the elongate puncture device is positioned at the proximal end of the introducer hub, the tip of the elongate puncture device is in line with the distal end of the shaft of the introducer shaft.

[0029] In some embodiments of the eighth broad aspect, the elongate puncture device includes a radiofrequency guidewire. [Brief description of the drawings]

[0030] In order that the invention may be more readily understood, an embodiment thereof will now be described by way of example only with reference to the accompanying drawings, in which: FIG.

[0031] [Figure 1] 1 is an illustration of a radio frequency (RF) guidewire, in accordance with one embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view of the embodiment of FIG. [Diagram 3] FIG. 3 is a diagram of a detail of FIG. 2; [Figure 4] 1 is an illustration of a stylet, according to one embodiment of the present invention. [Diagram 5] FIG. 5 is a cross-sectional view of the embodiment of FIG. [Figure 6] FIG. 5 is a diagram of detail A of FIG. 4. [Figure 7]FIG. 2 is a perspective view of an introducer with a stylet housed therein, according to one embodiment of the present invention. [Figure 8] FIG. 8 is a side view of the embodiment of FIG. [Figure 9] FIG. 8 is an end view of the embodiment of FIG. [Figure 10] FIG. 8 is a top view of the embodiment of FIG. [Figure 11] FIG. 9 is a cross-sectional view of the embodiment of FIG. [Figure 12] FIG. 12 is a diagram of detail A of FIG. [Figure 13] 1 is a diagrammatic representation of an apparatus according to one embodiment of the present invention. [Figure 14] 1 is an illustration of a distal end of an introducer with an elongated puncture device housed therein, according to one embodiment of the present invention. [Figure 15] 15 is a diagram of the embodiment of FIG. 14 with the elongate puncture device expanded to form a J-tip. [Figure 16] 14 is a diagram of the proximal end of the hub of FIG. 13 with an elongated puncture device inserted therein. [Figure 17] FIG. 2 is a schematic cross-sectional view of an introducer with an elongated puncture device installed, according to one embodiment of the present invention. [Figure 18] 1 is a diagrammatic representation of the layers surrounding the heart. [Figure 19] 1 is a diagram of an EGM wave showing a series of elevated ST segments. [Figure 20-1] 1 illustrates a method according to one embodiment of the present invention. [Figure 20A] 1 illustrates a method according to one embodiment of the present invention. [Figure 20B] 1 illustrates a method according to one embodiment of the present invention. [Figure 20C] 1 illustrates a method according to one embodiment of the present invention. [Figure 20D] 1 illustrates a method according to one embodiment of the present invention. [Figure 20E] 1 illustrates a method according to one embodiment of the present invention. [Figure 20F] 1 illustrates a method according to one embodiment of the present invention. [Figure 21A] Illustrate possible problem scenarios. [Figure 21B] Illustrate possible problem scenarios. [Figure 22A] 1 is an illustration of different manufacturers' configurations of elongated puncture devices. [Figure 22B] FIG. 22B is a cross-sectional view of FIG. 22A. [Figure 23A] 13 is a diagram of fluid flow from the radial gap at the distal end for the introducer. [Figure 23B] 1 is a diagrammatic representation of an introducer with a side port for fluid flow. [Figure 24] 1 illustrates an embodiment of a different stylet; [Diagram 25] 1 illustrates an alternative embodiment of a mandrel. [Figure 26] 1 is an illustration of an introducer hub with a tip orthosis. [Figure 27] FIG. 27 is an enlarged view of a portion of FIG. 26. [Figure 28] 13 is an illustration of an alternative embodiment of an introducer distal tip. [Figure 29A] 1 is a diagram of an introducer with a flexible tip and a stylet inserted. [Figure 29B] FIG. 29B is an illustration of the introducer of FIG. 29A with the stylet removed. [Figure 30A] 1 illustrates steps of a method for advancing an elongated puncture device through an introducer shaft. [Figure 30B] 1 illustrates steps of a method for advancing an elongated puncture device through an introducer shaft. [Figure 30C] 1 illustrates steps of a method for advancing an elongated puncture device through an introducer shaft. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] Minimally invasive catheterization of cardiac chamber spaces is required for the diagnosis and treatment of various arrhythmias. Although epicardial ablation is the preferred route in many situations (e.g., in cases of ventricular tachycardia), physicians may resort to general endocardial ablation due to uncertainties involved in access and high clinical complication rates. The current standard procedure for epicardial access is facilitated by the use of a 17Ga Tuohy needle to percutaneously puncture the pericardial sac via a subxiphoid, parasternal intercostal or apical approach. This puncture is typically performed under fluoroscopic guidance using a combination of anterior-posterior and lateral views. Radiopaque contrast is injected periodically to provide positive feedback to the user on tip position and whether the needle tip has successfully broached the pericardial sac. This approach has the potential to tear the epicardium, cardiac vessels, or surrounding soft tissue structures. There is also a risk of accidental entry into the ventricle, which can lead to effusion and possibly tamponade. Any new device or method that improves safety and predictability to identify the target tissue site and reduce the potential for complications would be beneficial.

[0033] The inventors have come up with a unique and previously undiscovered solution to improve the safety of procedures for puncturing target tissue with a puncture device, which includes using a method to verify the location of the tip of the puncture device relative to the target tissue. The method includes using an elongated device (e.g., a radio frequency (RF) guidewire) having a tip electrode configured to collect local electrograms (EGMs) and deliver energy to puncture the tissue, the method including collecting EGMs to indicate tip location relative to the target tissue. The elongated device does not specifically measure EGMs, but passes signals to an EGM signal processing device. In some embodiments, the target tissue is on the pericardium, and the method includes collecting local epicardial electrograms (EGMs) to indirectly measure and monitor pressure applied against a pericardial target tissue site. In other embodiments, the tissue is the septum of the heart, and the method includes collecting intracavitary electrograms (EGMs) to indirectly measure and monitor pressure applied against the septum. Exemplary embodiments include collecting EGM signals during tenting of the target tissue.

[0034] One embodiment is of a guidewire operable to provide tip information to a user in locating the tip of the device in reference to a target tissue. The present invention uses local epicardial electrograms (EGMs) to aid in locating the guidewire tip when approaching the heart and docking with the target tissue before and after puncturing the sac.

[0035] With specific reference now to the drawings in detail, it is emphasized that the details shown are exemplary and are intended only for the illustrative description of certain embodiments of the invention. Before describing at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments or of being practiced or carried out in various ways. It is also to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting.

[0036] An example of a system (or kit) of equipment suitable for carrying out the methods disclosed herein is shown in FIG. 13. The equipment includes an elongated puncture device 100, a stylet 120, and an introducer 130. Although the present disclosure uses the term "elongated puncture device" for purposes of explanation with respect to the elongated puncture device 100, the elongated puncture device 100 is generally an elongated member capable of delivering energy to tissue through a distal electrode. The elongated puncture device 100 is flexible in some embodiments and rigid in other embodiments. Examples of flexible embodiments include wires capable of delivering electrical energy, such as RF guidewires. Examples of rigid embodiments include needles operable to gain access to the pericardial space (some of which have a form and feel similar to a 17Ga-20Ga Tuohy needle) or needles operable to gain phrenic access (some of which have a form and feel similar to a Brockenbrough needle). Also, exemplary embodiments of the elongate puncture device 100 are operable to deliver electrical energy at frequencies other than radio frequency. The energy frequency used in a given procedure is typically determined by the user selecting a frequency from the range of frequencies available in the generator used in that procedure.

[0037] The introducer 130 of FIG. 13 is connected to a valve 140 by tubing 144. In the illustrated embodiment, the valve 140 is a three-way stopcock valve. Alternative embodiments have other valve configurations operable to deliver and withdraw fluid. The device of FIG. 13 may be used in a variety of tissue puncture procedures, for example, a pericardial puncture procedure or a transseptal puncture procedure. The major components of the device shown in FIG. 13 are described in more detail below.

[0038] Referring to FIG. 1, one embodiment of an elongated puncture device 100 includes a distal end portion 110 with a J profile and a straight portion 112 at its distal end. The elongated puncture device assumes a J shape when unconstrained. The J profile of the distal end portion 110 helps minimize tissue trauma when tracking the distal tip over the surface of the heart. The distal end portion 110 can also be a "P" or straight profile. Some embodiments have a distal tip angle of 0-35 degrees from the longitudinal axis of the main shaft. The idea is for the straight portion 112 of the distal tip to track around the heart to prevent it from rocking and impinging adjacent soft tissue structures. The distal curve should also be in-plane with the wire body for predictable advancement of the device. One embodiment has a J profile with an outer diameter of 10-12 mm. The straight portion 112 of the distal tip allows for alignment and orientation of the elongated puncture device tip to the introducer to facilitate RF puncture. One embodiment has a straight active tip length of 6-9 mm. This length is required to allow the user to control the alignment of the elongated puncture device by hand. The distal tip straight section 112 has a sufficient body length to allow alignment and positioning of the tip relative to the introducer.

[0039] The electrode 102 is at the end of the straight section 112. The guidewire has a blunt electrode to safely dock with the tissue, thereby facilitating the delivery of RF energy directly to the target tissue with which the electrode is in contact. Typically, the electrode 102 has a dome profile that minimizes the chance of premature mechanical puncture, allowing the elongated puncture device to dock with the target tissue at various angles. The electrode dome 103 embodiment may have a hemispherical, elliptical, or parabolic shape. In some embodiments, the electrode dome 103 carries a radiopaque marker 104. In alternative embodiments, other orientations and materials are used to secure the radiopaque material to the distal end of the elongated puncture device 100. Referring to FIG. 2, the proximal end portion of the elongated puncture device 100 (i.e., the end at the end opposite the end of the wire carrying the electrode 102) is not insulated and is operable to connect to a power source or generator. In some embodiments, the proximal end electrically exposed mandrel 108 is approximately 7.5 + / - 2.5 mm long. In an exemplary embodiment, the mandrel 108 is electrically conductive, the proximal end portion of the mandrel 108 is not insulated, and is operable to connect to a power source such that the distal tip electrode 102 is in electrical communication with the power source, thereby allowing energy to be delivered to tissue through the distal tip electrode 102 and enabling the distal tip electrode to record epicardial EGMs.

[0040] The elongated puncture device 100 of Figure 13 includes a proximal marker 116. Laser etching can be used to form the proximal marker 116 so that it cannot be removed during use or sterilization. The use of the proximal marker 116 is described below.

[0041] Some embodiments of the elongate puncture device 100 include a mandrel 108 that is electrically conductive and covered by a transparent insulating layer 114 (transparent heat shrink 115) and shorts out the distal end of the mandrel 108 such that the distal end of the mandrel 108 is electrically exposed (i.e., uncovered) to define the distal tip electrode 102. A portion of the mandrel 108 is surrounded by a visible marker 117 with the visible marker being covered by a transparent layer, and the portion of the elongate puncture device at and adjacent the visible marker 117 has a constant outer diameter.

[0042] Some embodiments of the elongated puncture device 100 include one or more markers 117 formed by mechanically grinding the oxide coating of the wire produced during heat treatment of the wire to fine-tune the transformation temperature. The markers 117 can be proximal, intermediate, or distal markers. The formation of such markers is described with reference to FIGS. 22A and 22B. FIG. 22b shows a cross section of the wire at point "A" in FIG. 22A after the wire has been heat treated. FIG. 22B illustrates the elongated puncture device 100 including a solid mandrel 100 surrounded by an oxide coating 118 that is covered by a transparent heat shrink 115 (transparent layer). In a typical embodiment, the mandrel 108 is constructed of Nitinol, but in some alternative embodiments, it is stainless steel. A typical oxide coating 118 on the wire is a titanium dioxide (TiO(2)) oxide layer. This coating is typically stable and acts as a barrier against ion exchange. After heat treatment, the oxide coating 118 extends the entire length of the wire. Typically, a portion of the coating at the proximal end is removed to allow electrical connection with an over-the-wire cable connector, and at least one other portion of the coating is removed to form a marker that is visible without imaging, i.e., a marker that is visible to the naked eye. The oxide coating 118 can be removed by grinding the surface of the wire to a desired profile, thereby forming the marker 117. The transparent heat shrink 115 typically comprises clear PTFE formed from an extruded tube that is heat shrunk onto the wire. The configuration of the marker in the elongated puncture device 100 maintains a smaller consistent outer diameter (i.e., does not increase the outer diameter) while maintaining electrical integrity by including the marker under the transparent heat shrink 115. Alternative embodiments of the heat shrink 115 are comprised of a transparent layer formed from alternative materials known to those skilled in the art. The elongated puncture device 100 is electrically insulated by the transparent heat shrink that makes the marker 117 visible. In some examples, the transparent layer has a thickness in the range of about 0.086 mm to 0.118 mm.

[0043] FIG. 22A shows different examples of markers 17. FIG. 22A-i shows a distal marker 117. FIG. 22A-ii shows a distal marker 117 and an intermediate marker 117. FIG. 22A-iii shows two intermediate markers 117. The proximal marker 116 of FIG. 17 can be formed by removing the oxide and coating the wire with a transparent layer as described above. In some such embodiments, the visible marker 117 comprises at least a portion of a mandrel and the oxide coating is applied directly to, i.e., in direct contact with, the mandrel.

[0044] FIG. 3 illustrates Detail C of FIG. 2. The embodiment of FIG. 3 includes a mandrel 108 (0.011 inch or 0.28 mm outer diameter) with a radiopaque coil 106 (0.017 inch or 0.43 mm outer diameter) covering a portion thereof. Insulation 114 (0.028 inch or 0.71 mm outer diameter) covers the mandrel 108 and the radiopaque coil proximal to the electrode 102, allowing delivery of electrical energy through the electrode 102 (0.0275 inch or 0.70 mm outer diameter, 0.01375 inch or 0.35 mm radius). In some embodiments, the electrical insulator is constructed of heat shrink (e.g., polytetrafluoroethylene (PTFE)). The radiopaque coil 106 extends around the curve of the distal end portion 110 (FIG. 2). The radiopaque coil aids the physician in determining the location of the distal tip of the elongated puncture device while using fluoroscopy. The physician may reduce fluoroscopy intensity for long procedures which reduces visibility of the guidewire. The coil may also improve echogenic properties when using ultrasound to visualize the guidewire tip. The coil may be 3 cm or longer. The coil also helps visualize the guidewire track around the cardiac silhouette. The coil helps to better visualize the "J" profile of the distal tip and how it interacts in space. It may aid the physician in helping to determine evidence of adhesions or anatomical abnormalities. The RO coil may be longer or shorter than 3 cm and may be constructed of various materials such as platinum, titanium, gold, and tungsten. Some embodiments include a radiopaque coating around the mandrel. In some such embodiments, the wire is coated with a thin precious metal. From the distal radiopaque coil 106, the electrode 102 includes a radiopaque marker 104 (outer diameter 0.0275 inches or 0.70 mm, inner diameter 0.011 inches or 0.28 mm, length 0.020 inches or 0.51 mm) surrounding a mandrel 108. The radiopaque marker 104 may also be referred to as a radiopaque (RO) band or puck. The radiopaque marker 104 aids in visualizing the location of the tip under fluoroscopy.The RO band can help to confirm whether the tip of the elongated puncture device protrudes from the tip of the introducer 130. Embodiments of the RO band may be of various lengths and constructed of various materials, such as platinum, titanium, gold, and tungsten. The elongated puncture device 100 is also visible using an ultrasound imaging system, with the radiopaque coil 106 being particularly echogenic.

[0045] The electrode 102 also includes an electrode dome 103 that may be formed by laser welding. In an exemplary embodiment, the wire mandrel, mandrel 108, is constructed of a shape memory material (e.g., Nitinol) that allows for kink resistance. The guidewire can undergo sharp deflections as it is introduced into the pericardial space. The flexible mandrel prevents any kinking and mitigates the possibility of the guidewire becoming trapped within the body. In some alternative embodiments, the mandrel 108 is constructed of stainless steel, which is less kink resistant. In other alternative embodiments, the mandrel is made of other superelastic materials with various dimensions and cross sections. In some embodiments, the radiopaque coil 106 is constructed of tungsten. Some exemplary embodiments include a radiopaque marker 104 constructed of a mixture of platinum and iridium (e.g., 10% iridium) and the electrode dome 103 constructed of dome-welded Nitinol. The distal tip region is soft (i.e., not rigid) to minimize tissue trauma when tracking across the cardiac surface. To accomplish this, the mandrel tapers in diameter at the distal end from .025 inch (0.64 mm) to .006 inch (0.15 mm) over a length of 25 cm. The tip is deflected to create a secondary bumper to that of the "J" tip profile.

[0046] The elongated puncture device 100 has a length of about 150 to about 180 cm and can deploy the guidewire into the pericardial space and wrap around the heart one to two times to define a cardiac silhouette under fluoroscopy. Alternative embodiments of the wire have smaller or larger lengths to accommodate various patient sizes and BMIs, e.g., lengths from 120 to about 180 cm. The elongated puncture device 100 typically has a lubricious coating to ensure that the guidewire tracks smoothly around the heart within the pericardial space.

[0047] In some embodiments, the shaft of the elongated puncture device 100, the radiopaque marker 104, and the proximal marker 116 have an outer diameter <=0.035 inches (0.89 mm). The radiopaque marker 104 is constructed of platinum and iridium (Pt / Ir) and has an inner diameter >=0.01 inches (0.25 mm). The guidewire mandrel 108 is made from Nitinol, which is designed to be kink resistant. An alternative embodiment (FIG. 25) is a composite of a superelastic material, such as Nitinol, providing a flexible kink resistant distal tip portion 108a and a proximal wire portion 108b of a stiffer alloy, such as stainless steel. These materials can be welded (e.g., weld 109), press fitted, or glued together, using an inner mandrel section 107 extending from the distal tip portion 108a, in the example of FIG. 25. In a further alternative embodiment, the inner mandrel section 107 extends from the proximal wire portion 108b.

[0048] The body of the guidewire (elongated puncture device 100) is insulated with polytetrafluoroethylene (PTFE). A typical embodiment of the elongated puncture device 100 has an outer diameter of <=0.035 inches (0.89 mm), however, any size outer diameter of the guidewire is acceptable as long as it fits within the spreader used in the epicardial procedure. Alternative embodiments of the radiopaque marker 104, which is a component of the smaller diameter elongated puncture device, have an inner diameter of less than 0.01 inches (0.25 mm). An exemplary embodiment of the introducer 130 has an inner diameter of >=0.035 inches (0.89 mm), however, other inner diameter sizes of the introducer are possible as long as the elongated puncture device 100 used in the procedure can pass through it.

[0049] 4 is an illustration of one embodiment of a stylet 120 including a stylet mandrel 122, a stylet cap 124, an adhesive 126, and a rounded end 128. In alternative embodiments, the tip is sharp. Some alternative embodiments do not include the adhesive 126.

[0050] FIG. 5 is a cross-sectional view of the embodiment of FIG. 4 showing the internal detail of the stylet cap 124. FIG. 6 is an illustration of Detail A of FIG. 4 showing the rounded end 128. In an alternative embodiment (FIG. 24, ii-v), the cross-section changes along the length of the stylet 120 to neck down (or taper) toward the distal tip, allowing better flow of contrast or fluid through the tip of the introducer when the stylet is seated. FIG. 24i illustrates a non-tapered stylet 120 inside an introducer 130. FIG. 24vi illustrates a helical embodiment of the stylet 120.

[0051] FIG. 7 shows one embodiment of an introducer 130 with a stylet housed therein. The introducer 130 includes an introducer shaft 134 connected to a hub 132. The hub 132 has a male side port 136 for connecting to a tube 144 (FIG. 13) and a receiving opening (FIG. 16) for receiving a stylet or wire. Alternative embodiments have other side port configurations operable to deliver and withdraw fluids. The stylet cap 124 of an installed stylet is proximal to the hub 132 and the rounded end 128 of the stylet is distal to the introducer shaft 134. In some embodiments, the introducer shaft is a reinforced 8Fr shaft coated with high-density polyethylene (HDPE) composed of 20% BaSO4. The introducer 130 is operable to house a flexible, elongated puncture device that enables the introducer 130 (with the elongated puncture device inserted therein) to traverse the fatty tissue to reach the target tissue, to facilitate delivery of RF energy by supporting proper alignment, orientation, and position of the distal tip of the elongated puncture device, and to enable a guidewire to be deployed within the pericardial space.

[0052] Alternative embodiments of the introducer distal tip 131 may be straight, curved, or bent at 15-45 degrees, such as the example in Figure 28. A curved or bent tip would allow the ability to align, orient, and position the distal tip of the elongated puncture device more tangentially relative to the cardiac silhouette.

[0053] The introducer is designed to allow "front loading", which is the insertion of a guidewire through the proximal hub, and / or "back loading" through the distal tip of the introducer. Alternative embodiments allow only specific compatible guidewires to limit use. With reference to FIGS. 26 and 27, a tip orthodontic device 137 having a distal tip radius of less than .057 inches (1.45 mm) allows insertion of an elongated puncture device 100 through the receiving opening 147 and valve 139, and into the introducer proximal hub 132 inside its diameter. This allows the distal tip of the introducer to be obtained in close proximity to the valve to facilitate seamless guidewire insertion.

[0054] An alternative embodiment of the introducer is the ability to accommodate and introduce multiple guidewires to facilitate downstream work flow. The introducer can accommodate multiple guidewires up to 0.014 inches or 0.018 inches in diameter, for example, if the introducer has an inner diameter of 0.035 inches (0.89 mm).

[0055] The introducer 130 and elongate puncture device 100 are configured such that the introducer 130 has the ability to deliver and withdraw fluids while the elongate puncture device is cannulated, even with the elongate puncture device inserted. The introducer shaft 134 is typically >=5 inches (12.7 cm). In one embodiment (FIG. 23A), the radial clearance between the introducer tip 131 ID and the elongate puncture device 100 OD is >.001 inches (0.025 mm) to provide sufficient constant flow 135 (>15 ml / min at 10 PSI (or 69 kilopascals)), measured by manually delivering fluid into a beaker for 1 minute at a constant 10 psi (69 kilopascals) and then measuring the volume of fluid at the end of the minute. In one such embodiment, the introducer tip lumen ID is 0.0385 (0.978 mm) + / - .0005 inches (0.013 mm) and the maximum elongated puncture device OD is .0350 (0.889 mm) + / - .0005 inches (0.013 mm), thereby the minimum clearance for this geometry is .00125 inches (0.032) mm. Another embodiment of the introducer (FIG. 23B) has a side port 131 located at the introducer tip 131, allowing for constant flow 135. The introducer shaft 134 has an operable length to reach the pericardial sac while providing the physician with adequate stiffness and control and a handle outside the patient's chest wall. In an alternative embodiment, the introducer shaft 134 is less than 5 inches (12.7 cm). To provide adequate reach and a controlled linear trajectory, one embodiment of the introducer 130 has a shaft of approximately 15 cm and a stiffness >0.04 Nm2, with a shaft of 12 cm and a stiffness >0.03 Nm2. Another alternative length is 4-6 cm to accommodate younger children and 7-10 cm to accommodate older children.

[0056] An alternative embodiment of the distal tip 131 of the introducer 130 (FIGS. 29A and 29B) includes a flexible tip 2-3 cm in length. The tip is supported by the rigid distal tip of the assembled stylet 120 (FIG. 29A) to facilitate the ability to traverse adipose tissue. However, once the stylet is removed, the distal tip of the introducer becomes flexible. The flexible tip allows for the alignment, orientation, and positioning of the elongated puncture device to be more tangential to the cardiac silhouette (FIG. 29B), instead of a perpendicular approach.

[0057] An alternative embodiment is a manually reshapeable introducer shaft, which allows the physician to create a desired curve in the introducer shaft, facilitating a curvilinear device insertion trajectory to get under the sternum to reach the pericardial sac. This ability reduces the required length of the device in patients with large abdomens or those with lower intercostal margins (rib cages).

[0058] FIGURE 8 is a side view of the embodiment of FIGURE 7, showing the introducer shaft 134, hub 132, and male port 136 of the introducer, and the stylet cap 124 and rounded end 128 of the stylet. When the blunt stylet 120 is introduced into the introducer 130, the stylet-introducer combination is operable to advance through adipose tissue to reach the target tissue. FIGURE 9 is an end view of the embodiment of FIGURE 7, illustrating the hub 132 and male port 136. FIGURE 10 is a top view of the embodiment of FIGURE 7, showing the stylet distal stylet cap 124, hub 132, and rounded end 128 of the introducer.

[0059] FIG. 11 is a cross-sectional view of the embodiment of FIG. 8. FIG. 11 shows the stylet mandrel extending from the rounded end 128 to the inside of the stylet cap 124. To accommodate advancement through tissue, the rounded end 128 of the stylet 120 has a diameter of .0375 inches or less, yet is less sharp than a Tuohy needle. FIG. 12 is an illustration of Detail A of FIG. 11, illustrating the inside of the lumen defined by the introducer shaft 134 and the insulation 138 on the outer surface of the introducer shaft 134. In some embodiments, the introducer 130 has an inside diameter >= 0.035 inches (0.89 mm). The introducer shaft includes an inner metal tube 146 sandwiched (or interposed) between two layers of HDPE (insulation 138), with both ends of the insulation layers tipped to bond the layers together (i.e., joined together to form a tip). An introducer 130 having such a configuration, in combination with an elongated puncture device 100 that is a wire and insulated for most of its length with the exception of the electrode tip and proximal connector, can provide an effective apparatus for collecting local EGMs. One embodiment is a kit including an introducer 130 and an elongated puncture device 100, where the elongated puncture device includes a distal tip electrode 102 that allows for recording of epicardial EGMs, where the shaft of the elongated puncture device is electrically insulated to reduce noise in any collected local EGMs, where the introducer includes an introducer shaft 134 connected to a hub 132, where the introducer shaft includes an inner metal tube 146 that is interposed between two electrically insulating layers 138 with both ends of the two layers joined together to bond the layers together, to reduce noise in any EGMs collected by the elongated puncture device.

[0060] The insulator at the distal end of the introducer 130 is shaped to form a tip that allows the penetration section to transition through tissue as it is advanced. The length of the introducer shaft 134 is >=5 inches (12.7 cm). The hub 132 is constructed from plastic and includes a silicone seating valve. FIG. 12 also shows that the space between the stylet mandrel 122 and the introducer shaft 134 decreases toward the distal end of the introducer shaft 134, i.e., there is a tight fit between the stylet mandrel 122 and the introducer shaft 134 at the distal end of the introducer shaft 134.

[0061] FIG. 13 is an illustration of an embodiment of the device showing the size of the components relative to each other. FIG. 14 shows the elongated puncture device 100 extending from an introducer 130. Only a portion of the straight section 112 of the guidewire (FIG. 1) protrudes from the introducer. In some embodiments, the tip of the elongated puncture device 100 only protrudes 2 mm from the blunt end of the introducer. This can act as a depth stop that limits how deep the tip of the elongated puncture device can penetrate into the target tissue. The length of the tip protrusion can vary depending on the support of the tip by the introducer and electrode size. FIG. 15 shows a distal end portion 110 with a J profile extending from the introducer 130.

[0062] 16 shows the proximal end of the introducer hub with an elongated puncture device inserted such that the proximal marker 116 of the guidewire is lined up with the proximal edge of the hub. The proximal marker 116 is visible to the user without the use of an imaging system, i.e., visible to the naked eye. An exemplary embodiment of the proximal marker 116 is a visual marker, while in some alternative embodiments the proximal marker 116 is a tactile marker. In an exemplary embodiment of the device, this positioning of the proximal marker 116 is deployed by positioning the electrode 102 (FIG. 1) on the outside of the introducer near the distal end of the introducer, i.e., the electrode 102 extends slightly beyond the distal end of the introducer.

[0063] FIG. 17 is a schematic cross-sectional view of an introducer 130 with an elongated puncture device 100 installed therein. In an exemplary embodiment, both the introducer 130 and the elongated puncture device 100 include markers for positioning the elongated puncture device 100 relative to the introducer 130. In the embodiment of FIG. 17, the introducer shaft 134 has a distal marker 142 at its distal end to indicate the position of the distal end of the introducer shaft 134 under imaging, and the elongated puncture device has a radiopaque marker 104 at its distal end to indicate the position of the distal end of the elongated puncture device under imaging. The positions of the distal ends relative to each other can also be determined under imaging. FIG. 17 also shows an elongated puncture device with a proximal marker 116 at the proximal end of the introducer hub. In this illustrated embodiment, the tip of the elongated puncture device extends from the introducer shaft when the proximal marker 116 is positioned at the proximal end of the introducer hub, e.g., a line marker on the elongated puncture device helps to indicate when the tip is deployed. In an alternative embodiment, the tip of the elongated puncture device lines up with the distal tip of the introducer shaft when the proximal marker 116 is positioned at the proximal end of the introducer hub.

[0064] In the embodiment of Figures 30A-C, the introducer shaft 134 has a distal marker 142 at its distal end to indicate the location of the distal end of the introducer shaft 134 under imaging, and the elongate puncture device has a radiopaque marker 104 at its distal end to indicate the location of the distal end of the elongate puncture device 100 under imaging. Figures 30A-C show method steps for advancing the elongate puncture device 100 through the introducer shaft 134. Figure 30A shows the elongate puncture device 100 positioned with the distal end of the proximal marker 116 at the proximal end of the introducer hub, while the tip of the tip of the elongate puncture device is still inside the lumen of the introducer shaft. The elongate puncture device is advanced to the configuration of Figure 30B with the center of the proximal marker 116 at the proximal end of the introducer hub and the tip of the elongate puncture device aligned with the tip of the introducer shaft 134. The elongate puncture device is further advanced to the configuration of Figure 30C with the proximal end of the proximal marker 116 at the proximal end of the introducer hub and the tip of the elongate puncture device extending beyond the tip of the introducer shaft 134. The configuration of Figure 30C further includes a distal marker 142 on the introducer shaft 134 aligned with the radiopaque marker 104 at the distal end of the introducer shaft 134 to confirm the relative position of the elongate puncture device and the introducer under imaging.

[0065] In some embodiments of the method, the user uses the proximal marker 116 to position the elongated puncture device relative to the introducer without the use of an imaging system such as fluoroscopy, in a step that may be referred to as "macropositioning." Following "macropositioning," the user turns on the imaging system (e.g., fluoroscopy) for more precise positioning of the elongated puncture device relative to the introducer and target tissue, in a step that may be referred to as "micropositioning." Using the proximal and distal markers allows the user to perform the initial portion of positioning the device without fluoroscopy, thereby reducing the amount of x-rays to which the user and patient are exposed when compared to performing the entire procedure under fluoroscopy. In some alternative embodiments of the method, the portion of the procedure involving positioning the elongated puncture device relative to the introducer is performed without any fluoroscopy.

[0066] 18 is a diagram of the layers surrounding the heart. The ventricle 230 is surrounded by the muscle tissue of the heart, the myocardium 228. The pericardium 226 surrounds the myocardium 228 and is made up of a fibrous pericardium 232, a parietal layer 234, a pericardial cavity 236, and an epicardium 238. The pericardial cavity is often referred to as the pericardial space or space.

[0067] FIG. 19 is an illustration of an epicardial EGM wave showing an elevated ST segment in response to tenting the pericardium, resulting in an ischemic response of tissue affecting the local epicardial EGM. Such a wave can be collected using the electrodes 102 of the elongated puncture device 100 as the elongated puncture device advances and presses against the pericardium. Line (I) in FIG. 19 is a wave with no tenting (or no significant pressure) applied to the pericardium, and line (IV) is a wave with very significant tenting of the pericardium. Lines (II) and (III) are between the amounts of tenting that result in lines (I) and (IV).

[0068] FIG. 20-1 and FIG. 20A-20F illustrate one embodiment method. The methods described below can be performed using different embodiments of the aforementioned device. FIG. 20-1 illustrates a subxiphoid approach of the introducer 130 to the pericardium 226 and surrounding anatomical structures. When the blunt stylet 120 is introduced into the introducer 130, the stylet-introducer combination is operable to advance through the fatty tissue to reach the target tissue. Typically, the stylet 120 is fastened to the proximal end of the hub 132 of the introducer 130. The physician makes a small cut in the patient's skin, allowing the introducer 130 to pass through the dermis and fatty layers with the protruding stylet tip. The blunt end of the stylet 120 provides the necessary cutting action to separate the tissue to reach the target. Using a stylet with a blunt end is advantageous over a stylet with a beveled sharp end that tears the tissue as the device traverses it. Blunt tips are also more forgiving if the target tissue is inadvertently approached too closely. They are less likely to puncture the epicardial surface of the heart. Furthermore, other factors being equal, a stylet with a blunt tip provides more tactile feedback than a stylet with a sharp tip. Note that this procedure is performed under fluoroscopy.

[0069] After the stylet 120 is removed from the introducer 130, the introducer 130 has a rigid shaft that is flexible and can support the deployment of the elongated puncture device 100 with a soft tip. The guidewire has a dome tip (electrode dome 103) that can dock with tissue, preventing premature puncture. The physician can optimize the location of the tip of the wire. The introducer has an inner metal tube 146 that has a lip, typically within 0.5-2 mm from the tip. The inner metal tube 146 acts as a radiopaque marker to indicate where the tip of the introducer 130 is positioned. The physician positions the tip of the elongated puncture device 100 outside the introducer 130 to ensure proper delivery of RF electrical energy. The physician can advance and retract the tip of the wire under fluoroscopy to measure how far the wire protrudes from the tip of the introducer. FIG. 20A shows the electrode 102 of the elongated puncture device in contact with the pericardium without significant force being exerted. The relevant EGMs with low ST segments are shown below (shown at the bottom of the figure). Figure 20B shows the introducer 130 and electrode 102 with the guidewire exerting some force to cause tenting of the pericardium. The waves associated with Figure 20B are higher than those associated with Figure 20A. In this manner, EGMs can be measured while the device is being moved, or before or after the device is moved.

[0070] FIG. 20C shows energy being delivered through the electrode to the pericardial tissue. The ST segment of the EGM wave shows a higher elevation than the previous wave. The guidewire has a blunt electrode at its tip that docks securely with the tissue, thereby facilitating the delivery of RF energy directly to the target tissue in contact with the electrode 102. A short pulse (e.g., 1 / 3 second) of high voltage AC is delivered by the electrode to create a hole in the pericardial sac 235, which then protrudes beyond the guidewire tip. The delivery of a short pulse (e.g., 1 / 3 second) of RF energy helps limit the depth of puncture. The physician can use a longer pulse, but there is a risk of puncturing too deeply into the myocardial tissue. In alternative embodiments, the pulse is shorter or longer, depending on the power setting and the tissue puncture required.

[0071] FIG. 20D shows the distal portion of the introducer after it has been advanced into the pericardial space 236 and the associated wave with an elevated ST segment. The introducer 130 has a valve 140 (e.g., a stopcock) attached to it by a tube 144 (FIG. 13) and a valve built into the hub 132 (handle) to allow for simultaneous delivery of contrast media. This allows the physician to confirm the tip location of the introducer 130 with or without a guidewire in place. The inner diameter of the introducer 130 is large enough to accommodate contrast media flow with a cannulated wire. This configuration of the device allows the physician to withdraw fluid from the pericardial space. For example, if there is excess fluid or blood, this can be aspirated. The arrow in FIG. 20E represents imaging fluid being injected into the pericardial space 236. If imaging of the fluid indicates that the fluid is within the pericardial space 236, access to the space has been achieved.

[0072] 20F shows the tip of the elongated puncture device 100 being advanced into the pericardial space 236. The guidewire (elongated puncture device 100) can then be advanced more completely into the space. If the tip of the elongated puncture device continues to move freely after accessing the pericardial space, the physician can confirm access by wrapping the guidewire around the heart (i.e., advancing it around the cardiac silhouette) at least once and visualizing under fluoroscopy that the guidewire outlines the cardiac silhouette. The distal 3 cm of the elongated puncture device 100 has a radiopaque coil 106 that increases the visibility of the distal end portion 110 under visualization, thereby helping to confirm access to the pericardial space when advancing the tip of the elongated puncture device.

[0073] If the tip of the wire begins to bunch as the physician attempts to advance the elongated puncture device, this may indicate that access to the pericardial space 236 has not been achieved. Figure 21A illustrates a complex scenario in which the epicardium is not punctured and significant tenting occurs. Significant tenting is caused by significant pressure being applied, resulting in a wave with an elevated ST segment. Figure 21B illustrates another complex scenario in which the elongated puncture device passes through the pericardial space 236 and into the myocardium 228, resulting in a wave with an elevated ST segment similar to that of Figure 21A.

[0074] The elongated puncture device 100 has features that facilitate epicardial EGM collection (as well as features that facilitate non-epicardial EGM collection, such as EGM collection at the septum of the heart).

[0075] An exemplary embodiment of the elongated puncture device 100 includes a single electrode at the tip of the guidewire that allows for recording of epicardial EGMs from the distal tip of the elongated puncture device 100 while tenting tissue. An alternative embodiment of the elongated puncture device 100 has multiple electrodes at the tip to gather additional information.

[0076] Exemplary embodiments of the elongated puncture device 100 are constructed from a material that is electrically conductive to allow electrical current to flow therethrough.

[0077] The electrodes 102 are constructed of a material that provides a stable impedance contact with the tissue. The impedance depends on the electrode material, the tissue, the electrode surface area, and the temperature. Lower impedance means that the EGM signal is less likely to be silent (DC offset problem). In a typical embodiment, the electrodes are constructed of a solid material. In an alternative embodiment, the electrodes have a coating of a conductive material.

[0078] If the electrode surface area is too large, EGM recording resolution will be adversely affected. An electrode surface area that is too small is prone to electrical interference. Some embodiments of the electrode have a hemispherical electrode tip (electrode dome 103) with an outer diameter of 0.024 inches (0.62 mm) to 0.035 inches (0.89 mm). Such embodiments have been tested in vivo on a porcine study and found that the effect of varying the OD and surface area of ​​the electrode tip (using a CardioLab electrophysiology recording system) showed no observable difference between hemispherical electrode tips with outer diameters of 0.024 inches (0.62 mm) to 0.035 inches (0.89 mm). The electrode dome 103 has a dome-like geometry that ensures uniform contact with tissue at various trajectory angles. To allow the user to collect epicardial EGM to provide guidewire tip location, the tip electrode embodiment has a dome OD > .027 inches (0.686 mm) and a diameter of about 1.8 to about 2.4 mm. 2 (this dimension is accurate to one decimal place) to ensure that the electrode is large enough for effective EGM collection, yet small enough to pierce tissue. Additionally, to create a smaller puncture than a 17GaTuohy needle (OD<.058 inch or 1.5 mm), some embodiments have a distal tip electrode OD of about .0275 inch (0.70 mm).

[0079] The shaft of the elongated puncture device 100 has features that facilitate the collection of EGM signals. The shaft of the elongated puncture device 100 is electrically insulated to reduce noise from the collected local EGMs. Additionally, the inner diameter of the introducer 130 and the outer diameter of the elongated puncture device 100 allow the introducer and the elongated puncture device to fit together with clearance to facilitate the delivery of contrast agent simultaneously with the collection of epicardial EGMs.

[0080] The following methods can be performed using different embodiments of the apparatus described above: A method of using the above-described device to puncture target tissue to gain access to the pericardial space 236 includes the following steps.

[0081] (1) Connect an electrically insulated wire (e.g., an elongated puncture device 100 that is an RF guidewire) with one distal pole to a recording system with electrocardiogram reference to the patient (e.g., EKG pads, subcutaneous reference or intracardiac reference catheter).

[0082] (2) Puncture the patient's skin in a minimally invasive manner via a subxiphoid, parasternal intercostal, or apical approach using a rigid introducer and engaging stylet. Make a small incision in the patient's skin below the xiphoid process to begin introduction.

[0083] (3) The rigid introducer 130 and stylet 120 are advanced, under guidance of fluoroscopy and tactile feedback, through various dermal layers toward the pericardial sac of the heart to position the tip of the introducer near the pericardial sac. In some embodiments of the method, the stylet is insulated and connected to a recording system to facilitate collection of electrocardiogram information useful for positioning the tip of the device as it approaches the heart (i.e., in macro positioning).

[0084] (4) The stylet 120 is removed with the radially blunt end of the introducer docked with the pericardial sac and replaced with the elongated puncture device 100.

[0085] (5) The elongated puncture device 100 is advanced with the introducer 130 in contact with the outside of the pericardial sac.

[0086] (5a) A local epicardial electrogram EGM is recorded from the electrode tip of the elongated puncture device 100. As the guidewire moves through the introducer 130, there is little or no signal. Once the tip of the elongated puncture device 100 is near or protruding from the tip of the introducer 130, the guidewire begins to collect the EGM signal. Under fluoroscopic guidance, the guidewire is advanced until the tip protrudes 2 mm from the tip of the introducer, thereby making contact with the pericardial sac. The tip of the elongated puncture device 100 is blunt to prevent tearing the cardiac surface or prematurely puncturing the pericardial sac or myocardial tissue. The blunt tip allows the physician to optimize the location, orientation, and angle of the device's approach.

[0087] (5b) When the tip of the elongated puncture device contacts the pericardial sac, the amplitude of the waveform increases due to higher mechanical forces on the heart (tenting) due to the transient ischemic response of the pericardial sac and epicardial tissue. NOTE: If the device (electrode 102) is not over the pericardial sac, collect far-field EGMs or other local EGMs, for example from the septum.

[0088] (5c) Dock the elongated puncture device 100 to the introducer 130 and advance or retract the elongated puncture device and introducer together to increase or decrease the force required for successful puncture. The local EGM acts as an indirect pressure sensor. The recorded EGM tracing shows evidence of an elevated ST segment. The physician can monitor the amount of tissue tenting indicated by the amplitude of the ST segment. As part of the interactive approach, a set elevated ST segment is selected that the physician believes will provide sufficient tenting to avoid overshooting. The physician may also use tactile feedback when gripping the guidewire when docked against the pericardial sac. Contrast can also be injected out of the tip and through the introducer to confirm proper tenting of the sac.

[0089] (6) Deliver energy to the pericardial sac through the electrode 102 at the tip of the elongated puncture device 100. For safety, the energy is typically delivered as a pulse (e.g., 1 / 3 second). Some embodiments include delivering less energy in a pulse by selecting a lower power level or shorter pulse time if a higher pressure level was selected in step (5c). In such embodiments, there is an inverse relationship between the pressure exerted on the sac and the amount of energy delivered in the pulse. In a typical embodiment, the physician starts with a low pressure level in the first iteration to avoid overshooting, and with each iteration (while maintaining the same pulse time and energy level), the amount of pressure exerted on the pericardial sac is increased, with the physician looking for higher ST elevation to reattempt access.

[0090] (6a) Check whether the pericardial sac has been punctured (using the techniques described above) and access to the pericardial cavity has been gained. If punctured, the pericardial sac will then prolapse beyond the guidewire tip. If access has not been gained, the elongated puncture device is retracted and repositioned on the pericardial sac for another attempt and the physician returns to step (5c).

[0091] (7) Monitoring electrical activity on the epicardial surface using electrode 102 at the distal tip of elongated puncture device 100 (after RF puncture of the pericardial sac provides access to the pericardial cavity).

[0092] (8) Deploy the elongated puncture device 100 further into the pericardial space. Deploying the elongated puncture device 100 further into the pericardial cavity relieves pressure at the tip, causing a change in the EGM tracing. The physician may deliver contrast to further confirm access.

[0093] Some embodiments include the further step of deploying a guidewire (9) for tracking along the epicardial surface of the heart while acquiring local epicardial EGMs. The recorded signals can be input into an EP mapping system for additional information.

[0094] The elongated puncture device 100 can support a sheath. Exemplary embodiments include the further step of advancing a sheath and dilator over the elongated puncture device 100. Once the sheath tip is properly positioned within the pericardial space, the dilator and guidewire are removed. The sheath then provides an access portal for advancement and placement of a device, such as a mapping or ablation catheter, to facilitate diagnosis or treatment of various arrhythmias. Some such embodiments of this method include using a steerable sheath.

[0095] Additionally, some embodiments use a system that includes an amplifier capable of amplifying the voltage and measuring the impedance from the electrodes over a range of anatomically relevant frequencies (about 10 kHz to about 80 kHz).

[0096] Although not considered a step in the prescribed method, it is possible for an elongated puncture device to be implanted into the epicardium or ventricle after RF puncture. In these situations, the amplitude of the electrical activity (ST segment) will decrease, providing feedback to the user that the guidewire should be retracted and RF puncture can be retried. These situations can also be confirmed by fluoroscopy.

[0097] The method embodiments described above may use different embodiments of the apparatus embodiments described above (ie, different embodiments of the devices).

[0098] In a first broad aspect, embodiments of the invention include a method of verifying the position of a tip of a puncture device relative to a target tissue, the method including using an elongated puncture device having a tip electrode configured to collect EGMs and deliver energy to puncture the tissue, the method including the step of collecting EGMs with the tip electrode to indirectly measure and monitor pressure exerted by the tip electrode of the elongated puncture device against the target tissue. In a second broad aspect, embodiments of the invention include a method of puncturing a target tissue, the method including using an elongated puncture device having a tip electrode configured to collect EGMs and deliver energy to puncture the target tissue, the method including collecting EGMs to indirectly measure and monitor pressure exerted by the tip electrode of the elongated puncture device against the target tissue, thereby verifying the position of the tip electrode of the elongated puncture device against the target tissue.

[0099] The embodiments of the invention described above are intended to be exemplary only, and the scope of the invention is therefore intended to be limited only by the appended claims.

[0100] It is understood that certain features of the invention that are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.

[0101] Although the present invention has been described with specific embodiments thereof, many alternatives, modifications, and variations will become apparent to those skilled in the art. It is therefore intended to embrace all such alternatives, modifications, and variations that fall within the broad scope of the appended claims. All publications, patents, and patent applications mentioned in this specification are hereby incorporated by reference in their entirety into this specification as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference into this specification. In addition, citation or identification of any reference in this application should not be construed as an admission that such reference is available as prior art to the present invention. The technical ideas contained in the present disclosure are described below. (Appendix 1) A method for confirming the position of a tip of a puncture device relative to a target tissue includes using an elongated puncture device having a tip electrode configured to collect EGMs and deliver energy to puncture tissue, the method including a step of collecting EGMs using the tip electrode to indirectly measure and monitor pressure applied by the tip electrode of the elongated puncture device against the target tissue. (Additional Note) 2. The method of claim 1, wherein the target tissue is the pericardium. (Appendix 3) 2. The method of claim 1, wherein the target tissue is the septum of the heart. (Appendix 4) 4. The method of claim 3, wherein the target tissue is the atrial septum. (Appendix 5) 6. The method of any one of claims 1 to 5, wherein the elongated puncture device delivers radio frequency energy. (Appendix 6) 6. The method of claim 5, wherein the elongated puncture device is a radiofrequency stylet, a trocar, or a guidewire. (Appendix 7) 2. The method of claim 1, wherein the EGM is collected from the pericardium. (Appendix 8) 2. The method of claim 1, wherein the EGM is collected from the septum of the heart. (Appendix 9) 8. The method of claim 1 or 7, wherein the elongated puncture device applies pressure against pericardial tissue. (Appendix 10) 9. The method of claim 1 or 8, wherein the elongated puncture device applies pressure against the septum of the heart. (Appendix 11) A method for puncturing a target tissue includes using an elongated puncturing device having a tip electrode configured to collect EGMs and deliver energy to puncture the target tissue, the method including collecting EGMs to indirectly measure and monitor pressure applied to the target tissue by the elongated puncturing device, thereby confirming the position of the tip electrode of the elongated puncturing device relative to the target tissue. (Appendix 12) 12. The method of claim 11, wherein the target tissue is the pericardium. (Appendix 13) 12. The method of claim 11, wherein the target tissue is the septum of the heart. (Appendix 14) 14. The method of claim 13, wherein the target tissue is the atrial septum. (Appendix 15) 12. The method of claim 11, wherein the elongated puncture device delivers radiofrequency energy. (Appendix 16) 16. The method according to any one of claims 11 to 15, wherein the elongated puncture device is a radiofrequency guidewire. (Appendix 17) 12. The method of claim 11, wherein EGM is collected from the pericardium. (Appendix 18) 12. The method of claim 11, wherein the EGM is collected from the septum of the heart. (Appendix 19) 18. The method of claim 11 or 17, wherein the elongated puncture device applies pressure against pericardial tissue. (Appendix 20) 20. The method of claim 11 or 18, wherein the elongated puncture device applies pressure against the septum of the heart. (Appendix 21) 1. A method of gaining access to a pericardial space, comprising: (a) introducing a blunt stylet into an introducer; (b) advancing the blunt stylet and the introducer in combination through adipose tissue toward the pericardial tissue; (c) removing the stylet from the introducer; (d) placing a flexible elongate puncture device within the introducer; (e) advancing the tip of the elongate puncture device distal to the introducer under fluoroscopic guidance, thereby bringing an electrode of the elongate puncture device into contact with the pericardium without exerting any substantial force; (f) monitoring the EGM based on the electrodes of the elongated puncture device in contact with the pericardium to confirm the presence of a low ST segment; (g) exerting a force with the electrodes of the introducer and the guidewire to tent the pericardium; (h) monitoring the EGM to verify that the waves are higher than the waves of step (f); (i) delivering energy to the tissue of the pericardium through the electrodes; (j) monitoring the EGM, the ST segment being higher than the waves of step (f) and step (h). (Appendix 22) 22. The method of claim 21, wherein step (i) comprises delivering a short pulse of high voltage AC. (Appendix 23) 23. The method of claim 22, wherein the short pulse is 1 / 3 second. (Appendix 24) 22. The method of claim 21, further comprising the step of (k) advancing the distal portion of the introducer into the pericardial space and monitoring the EGM. (Appendix 25) 22. The method of claim 21, wherein steps (e) and (f) are performed simultaneously. (Appendix 26) 22. The method of claim 21, wherein steps (g) and (h) are performed simultaneously. (Appendix 27) 22. The method of claim 21, wherein step (i) and step (j) are carried out simultaneously. (Appendix 28) 25. The method of claim 24, further comprising the step (l) of delivering a contrast agent. (Appendix 29) 25. The method of claim 24, further comprising the step of (m) withdrawing fluid from the pericardial space. (Appendix 30) 25. The method of claim 24, further comprising the step of (n): advancing the tip of the elongate puncture device into the pericardial cavity. (Appendix 31) 25. The method of claim 24, further comprising the step of (n) advancing the elongated puncture device into the pericardial cavity. (Appendix 32) 32. The method of claim 31, further comprising the step of (o) confirming access by wrapping the guidewire at least once around the heart and visualizing under fluoroscopy. (Appendix 33) 1. A method of puncturing target tissue to gain access to the pericardial space, comprising: (1) connecting an electrically insulated wire having one distal pole to a recording system having an electrocardiogram reference for a patient; (2) puncturing the patient's skin via a subxiphoid, parasternal intercostal, or apical approach with a rigid introducer and an engaging stylet; (3) advancing the rigid introducer and the stylet under fluoroscopic and tactile feedback guidance through various dermal layers toward the pericardial sac of the heart to position the tip of the introducer proximate the pericardial sac; (4) removing the stylet and placing the elongate puncture device within the introducer while the radially blunt tip of the introducer is docked with the pericardial sac; (5) advancing the elongate puncture device while the introducer is in contact with the exterior of the pericardial sac; (6) delivering energy to the pericardial sac via an electrode at the tip of the elongated puncture device. (Appendix 34) 34. The method of claim 33, wherein step (5) includes recording local epicardial EGMs from the electrode tip of the elongated puncture device. (Appendix 35) 35. The method of claim 34, wherein step (5) further comprises monitoring the EGM to verify that waveform amplitude increases with higher mechanical forces on the heart. (Appendix 36) 34. The method of claim 33, wherein step (6) includes delivering the energy as at least one pulse. (Appendix 37) 34. The method of claim 33, wherein step (6) is wherein the energy is delivered as a series of pulses starting at a low pressure level to the pericardial sac in a first repetition to avoid overshoot, and the amount of pressure exerted on the pericardial sac is increased with each repetition while maintaining the same pulse time and energy level. (Appendix 38) 34. The method of claim 33, wherein step (6) includes checking whether the pericardial sac has been punctured and access to the pericardial cavity has been gained. (Appendix 39) 34. The method of claim 33, further comprising the step (7) of monitoring epicardial surface electrical activity using the electrode at the distal tip of the elongate puncture device (after RF puncture of the pericardial sac provides access to the pericardial cavity). (Appendix 40) 40. The method of claim 39, further comprising the step (8) of further deploying the elongate puncture device into the pericardial space to relieve pressure on the tip and induce a change in the EGM tracing. (Appendix 41) 41. The method of claim 40, further comprising the step (9) of deploying the guidewire to track along the epicardial surface of the heart while acquiring local epicardial EGMs. (Appendix 42) 41. The method of claim 40, further comprising advancing a sheath and a dilator over the elongate puncture device. (Appendix 43) A method for confirming the position of a tip of an elongated puncture device relative to an introducer, the elongated puncture device having a proximal marker visible to the naked eye and a distal tip marker visible under an imaging system, the introducer having a distal end marker visible under the imaging system, the method comprising: (1) positioning the elongated puncture device relative to the proximal end of the introducer using the proximal marker without an imaging system; (2) turning on the imaging system; and (3) positioning the distal tip of the elongated puncture device relative to the end of the introducer by viewing the distal tip marker and the distal end marker using the imaging system. (Appendix 44) 44. The method of claim 43, wherein the imaging system is a fluoroscopy system and the distal tip marker and the distal end marker are visible under fluoroscopy. (Appendix 45) An elongated puncture device comprising a mandrel covered by a conductive and transparent insulating layer, the transparent layer preventing shorting of the distal end of the mandrel such that the distal end of the mandrel is electrically exposed to define a distal tip electrode, a portion of the mandrel being surrounded by a visible marker, the visible marker being covered by the transparent layer, and the portion of the elongated puncture device at and adjacent to the visible marker having a constant outer diameter. (Appendix 46) 46. ​​The elongate puncture device of claim 45, wherein the mandrel is surrounded by an oxide coating covered by the transparent insulating layer, and the oxide coating is removed from at least one portion of the mandrel such that the at least one portion defines at least one visible marker. (Appendix 47) 47. The elongate puncture device of claim 46, wherein the at least one visible marker comprises at least a portion of the mandrel, and the oxide coating is in contact with the mandrel. (Appendix 48) 46. ​​The elongate puncture device of claim 45, wherein the visible marker may be a proximal marker, an intermediate marker, or a distal marker. (Appendix 49) 46. ​​The elongate puncture device of claim 45, wherein the transparent layer comprises a heat shrink layer. (Appendix 50) 48. The elongate puncture device of claim 47, wherein the heat shrink layer comprises a polytetrafluoroethylene material. (Appendix 51) 46. ​​The elongate puncture device of claim 45, wherein the mandrel is made of Nitinol. (Appendix 52) 46. ​​The elongate puncture device of claim 45, wherein the mandrel is constructed of stainless steel. (Appendix 53) 47. The elongate puncture device of claim 46, wherein the oxide coating is comprised of a layer of titanium dioxide. (Appendix 54) 54. The elongated puncture device according to any one of claims 45 to 53, wherein the elongated puncture device is flexible. (Appendix 55) 54. The elongated puncture device of any one of claims 45 to 53, wherein the mandrel is electrically conductive, a proximal end portion of the mandrel is not insulated, and the distal tip electrode is operable to be connected to a power source so as to be in electrical communication with the power source, such that energy can be delivered to tissue through the distal tip electrode, enabling the distal tip electrode to record epicardial EGMs. (Appendix 56) 56. The elongate puncture device of claim 55, wherein the shaft of the elongate puncture device is electrically insulated to reduce noise from any collected local EGMs. (Appendix 57) The distal tip electrode has an outer diameter of >0.027 inches (0.686 mm) and a diameter of about 1.8 to about 2.4 mm. 2 54. The elongate puncture device according to any one of claims 45 to 53, having a hemispherical dome with a surface area of (Appendix 58) 54. The elongate puncture device of any one of claims 45 to 53, further comprising a distal end portion having a J profile. (Appendix 59) 59. The elongate puncture device of claim 58, further comprising a radiopaque coil extending around the curve of the distal end portion having a J profile. (Appendix 60) 60. The elongate puncture device of claim 59, wherein an end of the radiopaque coil can be used as a distal tip marker. (Appendix 61) 60. The elongate puncture device of claim 59, wherein the radiopaque coil has echogenic properties when using ultrasound to enable visualization of the guidewire tip. (Appendix 62) An introducer for use with an elongated puncture device, the introducer including an introducer shaft connected to a hub, the introducer shaft including an inner metal tube interposed between two insulating layers with both ends of the two layers joined to one another to adhere the layers together. (Appendix 63) 63. The introducer of claim 62, wherein the two insulating layers are made of high density polyethylene. (Appendix 64) 64. The introducer of any one of claims 62 to 63, wherein the hub further comprises a male port for connecting to a tube and a receiving opening for receiving a stylet or wire, and is operable such that the hub is simultaneously attached to a fluid source while a stylet or wire is inserted into the hub. (Appendix 65) A kit including an introducer and an elongated puncture device, the elongated puncture device including a distal tip electrode that allows for recording of epicardial EGMs, the shaft of the elongated puncture device being electrically insulated to reduce noise in any collected local EGMs; The introducer includes an introducer shaft connected to a hub, the introducer shaft including an inner metal tube interposed between two electrically insulating layers with both ends of the two layers joined together to bond the layers, reducing noise in any EGMs collected by the elongated puncture device. (Appendix 66) 66. The kit of claim 65, wherein the introducer and the elongate puncture device are configured such that the introducer has the ability to deliver and withdraw fluids while the elongate puncture device is inserted therethrough. (Appendix 67) 67. The kit of claim 66, wherein a radial gap between an inner diameter of the tip of the introducer and an outer diameter of the elongate puncture device is >0.025 mm (.001 inch). (Appendix 68) 70. The kit of claim 67, wherein the kit is operable to provide a contrast flow of >15 ml / min at 69 kilopascals (10 PSI). (Appendix 69) 68. The kit of claim 67, wherein the inner diameter of the tip of the introducer is 0.978 mm (.0385 inches) + / - 0.013 mm (.0005 inches) and the maximum outer diameter of the elongated puncture device is 0.889 mm (.0350 inches) + / - 0.013 mm (.0005 inches), thereby providing a minimum gap for this geometry of 0.032 mm (.00125 inches). (Appendix 70) 70. The kit of any one of claims 65-69, further comprising a stylet, the cross-section of the stylet varying along the length of the stylet and tapering downwardly toward the distal tip of the stylet to allow fluid flow through the tip of the introducer when the stylet is placed. (Appendix 71) 70. The kit of any one of claims 65 to 69, further comprising a stylet, the stylet being electrically insulated and operable to be connected to a recording system to facilitate collecting EGM information useful for positioning the tip of the introducer when approaching the heart. (Appendix 72) 70. The kit of any one of claims 65 to 69, further comprising markers for positioning the elongated puncture device relative to the introducer, the elongated puncture device having a proximal marker visible to the naked eye and a distal tip marker visible under an imaging system, and the introducer having a distal end marker visible under the imaging system. (Appendix 73) 73. The kit of claim 72, wherein the distal tip marker and distal end marker are visible under fluoroscopy. (Appendix 74) 73. The kit of claim 72, wherein when the proximal marker of the elongate puncture device is positioned at the proximal end of the introducer hub, the tip of the elongate puncture device extends distally of the shaft of the introducer shaft. (Appendix 75) 73. The kit of claim 72, wherein when the proximal marker of the elongate puncture device is positioned at the proximal end of the introducer hub, the tip of the elongate puncture device is in line with the distal end of the introducer shaft. (Appendix 76) 44. The method of any one of claims 1-5, 11-15, 21, 33 and 43, wherein the elongated puncture device comprises a radiofrequency guidewire. (Appendix 77) 54. The elongated puncture device according to any one of claims 45 to 53, wherein the elongated puncture device comprises a high-frequency guidewire. (Appendix 78) 70. The kit of any one of claims 65 to 69, wherein the elongated puncture device comprises a high-frequency guidewire.

Claims

1. A kit comprising an introducer and an elongate puncture device, the elongated puncture device includes a distal tip electrode that allows for recording of an epicardial EGM, the shaft of the elongated puncture device being electrically insulated to reduce noise in any collected local EGM; the introducer includes an introducer shaft connected to a hub, the introducer shaft including an inner metal tube interposed between two electrically insulating layers with opposite ends of the layers joined together to bond the layers together, the inner metal tube reducing noise in any EGM collected by the elongated puncture device; The inner metal tube and the electrically insulating layer define a lumen configured to receive the elongate puncture device.

2. The kit of claim 1 , wherein the introducer and the elongate puncture device are configured such that the introducer has the ability to deliver and withdraw fluids while the elongate puncture device is inserted into the lumen.

3. 3. The kit of claim 2, wherein the radial gap between the inner diameter of the introducer tip and the outer diameter of the elongate puncture device is >0.025 mm (.001 inch).

4. 4. The kit of claim 3, wherein the kit is operable to provide a contrast flow of >15 ml / min at 69 kilopascals (10 PSI).

5. 4. The kit of claim 3, wherein the inner diameter of the introducer tip is 0.978 mm (.0385 inch) + / - 0.013 mm (.0005 inch) and the maximum outer diameter of the elongated puncture device is 0.889 mm (.0350 inch) + / - 0.013 mm (.0005 inch), thereby providing a minimum clearance for this geometry of 0.032 mm (.00125 inch).

6. 6. The kit of claim 1, further comprising a stylet, the cross-section of which varies along the length of the stylet and tapers downwardly towards the distal tip of the stylet to allow for fluid flow through the tip of the introducer when the stylet is placed.

7. 6. The kit of any one of claims 1 to 5, further comprising a stylet, the stylet being electrically insulated and operable to be connected to a recording system to facilitate collecting EGM information useful in positioning the tip of the introducer as it approaches the heart.

8. 6. The kit of claim 1, further comprising markers for positioning the elongate puncture device relative to the introducer, the elongate puncture device having a proximal marker visible to the naked eye and a distal tip marker visible under an imaging system, and the introducer having a distal end marker visible under the imaging system.

9. The kit of claim 8 , wherein the distal tip marker and the distal end marker are visible under fluoroscopy.

10. The kit of claim 8 , wherein when the proximal marker of the elongated puncture device is positioned at the proximal end of the hub of the introducer, the tip of the elongated puncture device extends distally of the shaft of the introducer shaft.

11. The kit of claim 8, wherein when the proximal marker of the elongated puncture device is positioned at the proximal end of the introducer hub, the tip of the elongated puncture device is aligned with the distal end of the introducer shaft.

12. The kit according to any one of claims 1 to 5, wherein the elongated puncture device comprises a radiofrequency guidewire.

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