Radiofrequency perforation apparatus

Abstract

To provide a medical device having improved visualization of a portion of the medical device insertable into a patient's body while minimizing obstruction of a fluid flow through a lumen of the device and while minimizing an increase in the outer diameter of the device attributed to the feature providing the improved visualization.SOLUTION: The device can include, for example, a marker 6 distal to a lumen 9 or, if the device comprises a tube such as a metallic tube 12, an imaging marker embedded into a wall of the tube. Another embodiment includes attaching a marker to the surface on the inside of a lumen of a medical device without embedding the marker. Various alternative embodiments, methods and applications of using such devices are also disclosed.SELECTED DRAWING: Figure 10b

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to improved visualization of medical devices, particularly devices that include lumens for fluid flow.

[0002] In order that the invention may be more readily understood, embodiments thereof are shown by way of example in the accompanying drawings, in which: [Brief explanation of the drawings]

[0003] [Figure 1] 1 is a diagram of an embodiment of an instrument including a handle and a shaft. [Figure 2a] FIG. 1 is a schematic side view illustrating an embodiment having a shaft or elongate member with a lumen and a marker distal to one or more openings. [Figure 2b] FIG. 10 is a schematic side view illustrating another embodiment having a shaft or elongate member with a lumen and a marker distal to one or more openings. [Figure 2c] FIG. 10 is a schematic side view illustrating another embodiment having a shaft or elongate member with a lumen and a marker distal to one or more openings. [Figure 2d] FIG. 10 is a schematic side view illustrating another embodiment having a shaft or elongate member with a lumen and a marker distal to one or more openings. [Figure 3a] FIG. 1 is a schematic side view illustrating an embodiment in which markers are embedded in the wall of a metal tube. [Figure 3b] FIG. 10 is a schematic side view showing another embodiment in which markers are embedded in the wall of a metal tube. [Figure 3c] FIG. 10 is a schematic side view showing another embodiment in which markers are embedded in the wall of a metal tube. [Figure 3d] FIG. 10 is a schematic side view showing another embodiment in which markers are embedded in the wall of a metal tube. [Figure 3e]FIG. 10 is a schematic side view showing another embodiment in which markers are embedded in the wall of a metal tube. [Figure 3f] FIG. 10 is a schematic side view showing another embodiment in which markers are embedded in the wall of a metal tube. [Figure 3g] FIG. 10 is a schematic side view showing another embodiment in which markers are embedded in the wall of a metal tube. [Figure 3h] FIG. 10 is a schematic side view showing another embodiment in which markers are embedded in the wall of a metal tube. [Figure 3i] FIG. 10 is a schematic side view showing another embodiment in which markers are embedded in the wall of a metal tube. [Figure 3j] FIG. 10 is a schematic side view showing another embodiment in which markers are embedded in the wall of a metal tube. [Figure 4a] FIG. 10 is a schematic side view illustrating an embodiment in which markers are bonded to the inner surface of the wall of a metal tube. [Figure 4b] FIG. 10 is a schematic side view of another embodiment in which markers are bonded to the inner surface of the wall of a metal tube. [Figure 4c] FIG. 10 is a schematic side view of another embodiment in which markers are bonded to the inner surface of the wall of a metal tube. [Figure 4d] FIG. 10 is a schematic side view of another embodiment in which markers are bonded to the inner surface of the wall of a metal tube. [Figure 4e] FIG. 10 is a schematic side view of another embodiment in which markers are bonded to the inner surface of the wall of a metal tube. [Figure 4f] FIG. 1 is a schematic side view showing an apparatus in which a captive element marker is held by an internal retainer bonded to the interior surface of the wall of a metal tube. [Figure 5] FIG. 10 is a side cross-sectional view of a distal portion of an embodiment of the device. [Figure 6a] 1 is a schematic side view of a device with a lumen and an internal marker between the ends of the lumen. [Figure 6b] FIG. 6b is a schematic end view of the device of FIG. 6a. [Figure 7a] FIG. 1 is a schematic side view of a device with a lumen and a hollow internal marker prior to fusion welding. [Figure 7b] FIG. 7b is a schematic end view of the device of FIG. 7a. [Figure 7c] FIG. 1 is a schematic side view of a device including a lumen and a solid internal marker prior to fusion welding. [Figure 7d] FIG. 7c is a schematic end view of the device of FIG. [Figure 8a] FIG. 7b is a schematic side view of the device of FIG. 7a after fusion welding. [Figure 8b] FIG. 8b is a schematic end view of the device of FIG. 8a. [Figure 8c] FIG. 7C is a schematic side view of the device of FIG. 7C after fusion welding. [Figure 8d] FIG. 8c is a schematic end view of the device of FIG. [Figure 9a] 1 is a diagram of an embodiment of the method of the present invention. [Figure 9b] 1 is a diagram of an embodiment of the method of the present invention. [Figure 10a] 1 shows certain views of an alternative embodiment of the device of the present invention; [Figure 10b] 1 shows another view of an alternative embodiment of the device of the present invention. [Figure 10c] 1 shows another view of an alternative embodiment of the device of the present invention. [Figure 10d] 1 shows another view of an alternative embodiment of the device of the present invention. [Figure 11a] 1 shows certain views of an alternative embodiment of the device of the present invention; [Figure 11b] 1 shows another view of an alternative embodiment of the device of the present invention. [Figure 11c] 1 shows another view of an alternative embodiment of the device of the present invention. [Figure 11d] 1 shows another view of an alternative embodiment of the device of the present invention. [Figure 11e] 1 shows another view of an alternative embodiment of the device of the present invention. [Figure 11f] 1 shows another view of an alternative embodiment of the device of the present invention. [Figure 11g]1 shows another view of an alternative embodiment of the device of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0004] Certain medical procedures require the use of medical devices that can: form perforations or channels in or through a material; transfer and / or withdraw fluids to / from a patient's body; and provide radiopaque markers for visualizing one or more steps of the medical procedure. Radiopaque bands placed on the exterior of the shaft of a medical device are often used for imaging. Because such external marker bands increase the outer diameter of the device, in some cases, dimensional constraints may require a smaller outer diameter, thereby preventing the use of devices with such external markers. Furthermore, because such external marker bands are typically located proximal to the device's most distal tip, the bands do not provide for accurate positioning of the device's distal tip. To avoid increasing the device's outer diameter, radiopaque markers may be placed inside the device's lumen, but: a) this is often not easy to achieve, depending on the size and configuration (e.g., material) of the device and the diameter of the lumen defined by the device; and b) this typically impedes fluid flow through the device's lumen.

[0005] The inventors have discovered and implemented several embodiments disclosed herein that allow for improved visualization of the portion of a medical device being inserted into a patient while minimizing obstruction to fluid flow through the lumen and avoiding increasing the outer diameter of the device. This may be accomplished, for example, by providing a radiopaque marker distal to the lumen opening (exit port / aperture) by making the diameter of the marker equal to or less than the diameter of the portion of the device adjacent to the marker, or by having an imaging marker substantially embedded in the wall of / within the tube, the device being a metallic tube or similar structure.

[0006] One specific embodiment includes a hemispherical, atraumatic distal tip with a radiopaque material fused to the end of a metal tube to form a radiopaque electrode tip at the distal tip of the device. The radiopaque electrode tip serves both to position the distal end of the device and to deliver energy, and the atraumatic shape significantly limits or prevents accidental damage to tissue. This embodiment may also include a longitudinally extending lateral port (lateral aperture) for fluid flow. Aspects of the embodiments described herein may also be included in other types of devices, such as devices without a lumen for fluid flow and devices that do not provide energy delivery.

[0007] In a first broad aspect, an embodiment of the present invention includes a medical device comprising an elongate member having a proximal end and a distal end, the elongate member defining a lumen extending substantially between the proximal and distal ends and having at least one opening from the lumen to the surrounding environment, the medical device having an imaging marker associated with the elongate member distal from the proximal end of the elongate member beyond the at least one opening.

[0008] In some embodiments of the first broad aspect, the radiopaque marker is disposed along the elongate member, and the outer diameter of the radiopaque marker is equal to or less than the outer diameter of the elongate member. In some embodiments of the first broad aspect, the radiopaque marker is a radiopaque marker, and in some embodiments, the distal end of the lumen is further closed. In some embodiments, the distal end of the lumen is further closed by a distal functional tip including the radiopaque marker, the functional tip being disposed at the distal end of the elongate member. In some embodiments, the functional tip is further comprised of a conductive material and is capable of transmitting energy. The energy may be electrical energy. More specifically, in some cases, the electrical energy has a frequency in the radio frequency range.

[0009] In some embodiments of the first broad aspect, the elongated member comprises a plastic tube, and in other embodiments, the elongated member comprises a metal tube. Alternatively, the elongated member may be a round tube, a coil, a braid, or a non-round conduit. Embodiments having a metal tube may further include an imaging marker attached to the metal tube by welding. Furthermore, a functional tip may be formed by fusion welding the distal end of the metal tube to a radiopaque filler or other radiopaque material, and the functional tip may have at least a dome or hemispherical portion. The functional tip blocks the distal end of the lumen.

[0010] In a second broad aspect, embodiments of the present invention include a medical device having an elongate member, e.g., a metal tube, having a proximal end, a distal end, and defining a lumen extending between the proximal and distal ends, the elongate member having at least one opening from the lumen. The medical device includes an imaging marker, such as a radiopaque marker (a "sidewall radiopaque marker") embedded in the wall of the elongate member at a marker location. The elongate member may be, for example, a round tube, a coil, a braid, or a conduit having a shape other than round.

[0011] In some embodiments of the second broad aspect, the sidewall radiopaque markers are embedded in the inner wall of the metal tube such that the diameter of the lumen is not reduced by the marker (the diameter of the lumen at the marker location is equal to or greater than the diameter of the lumen adjacent to the marker), thereby preventing fluid flow through the lumen from being impeded by the marker. In other embodiments, the sidewall radiopaque markers are embedded in the outer wall of the metal tube such that the outer diameter of the device is not increased by the marker, i.e., the diameter of the device at the marker location is equal to or less than the outer diameter of the device adjacent to the marker location.

[0012] In some embodiments of the second broad aspect, the medical device has a functional tip associated with the elongate member, the functional tip having an electrode disposed at a distal end of the elongate member and operable to transmit at least energy, Some such embodiments further include an outer diameter of the electrode equal to or less than the outer diameter of the elongate member.

[0013] In some embodiments of the second broad aspect, the distal end of the lumen is closed by a functional tip at the distal end of the elongate member. In some such embodiments, the functional tip further includes an electrode for energy transmission. The energy may be radio frequency energy. In some embodiments, the device has at least one side port (lateral aperture) from the lumen to the environment external to the elongate member.

[0014] In some embodiments of the second broad aspect, the functional tip has a radiopaque material that defines a radiopaque marker of the functional tip. The radiopaque marker of the functional tip may be attached to the metal tube by welding. Optionally, in some embodiments, the functional tip is formed by fusion welding the distal end of the metal tube and the radiopaque filler. In some embodiments, the functional tip has at least a dome-shaped portion.

[0015] In a third broad aspect, embodiments of the present invention include a medical device having an elongate member, such as a metal tube, having a proximal end, a distal end, and defining a lumen substantially between the proximal and distal ends, the elongate member having at least one opening / aperture from the lumen. The medical device has an imaging marker, such as a radiopaque marker, attached (bonded) to a surface of the inner wall of the metal tube inside the lumen. The elongate member may be, for example, a tube, a coil, a braid, or a non-round conduit.

[0016] In some embodiments of the third broad aspect, the medical device further includes a functional tip associated with and disposed at the distal end of the elongate member. The functional tip includes an electrode operable to transmit energy, which may be radio frequency electrical energy. In some such embodiments, an outer diameter of the electrode is equal to or less than an outer diameter of the elongate member, and a distal end of the lumen may be closed by the functional tip disposed at the distal end of the elongate member.

[0017] Some embodiments of the third broad aspect also include at least one lateral aperture (or side port) from the lumen. In some embodiments, the functional tip at the distal end is attached by welding.

[0018] In a fourth broad aspect, embodiments of the present invention include a method of forming a channel or perforation at a target location within a patient's body using a medical device including an elongate member and a functional tip associated with and disposed about a distal end of the elongate member, at least a portion of the functional tip being visible using medical imaging, the method having the steps of: a) visualizing the functional tip as the medical device advances through the patient's body to guide the functional tip to the target location; c) positioning the functional tip at the target location; and d) transmitting electrical energy through an electrode of the functional tip to form the channel or perforation.

[0019] Some embodiments of a method for forming a channel or perforation at a target location within a patient's body include: a) introducing into the patient's vasculature a medical device including an elongate member and a functional tip associated with and disposed around a distal end of the elongate member; b) advancing the medical device through the vasculature using the functional tip as a radiopaque marker for imaging of the distal end, thereby making the distal end steerable; c) positioning the functional tip at the target location; and d) transmitting electrical energy through the functional tip electrode to form a channel.

[0020] In some embodiments of the fourth broad aspect, the elongate member defines a lumen, the medical device has at least one opening from the lumen to an environment outside the elongate member, and the method further comprises flowing a fluid through the opening. In some embodiments, the distal end of the lumen is closed, and the elongate member has at least one lateral aperture (side port) from the lumen to an environment outside the elongate member, and the method further comprises flowing a fluid through the side port. Fluid, such as fluid visible in the image, can be delivered or withdrawn.

[0021] In some embodiments of the fourth broad aspect, step b) further comprises advancing the elongate member through the vasculature without substantially coring tissue. In some embodiments, step d) further comprises forming the channel without substantially coring tissue.

[0022] In some embodiments of the fourth broad aspect, the diameter of the functional tip is equal to or less than the outer diameter of the elongate member (shaft of the device), thereby facilitating or facilitating advancement of the elongate member through the vasculature; i.e., the functional tip does not increase the outer diameter of the device, which would be more difficult to advance if the outer diameter of the device were larger.

[0023] Optionally, in some embodiments, the energy transmitted in step d) is radio frequency electrical energy.

[0024] Some embodiments of the second and third broad aspects of the invention further include an outer insulating layer at least slightly overlapping the aperture in the metal tube and / or the longitudinally elongated aperture that enhances fluid flow. In some embodiments, the aperture is a lateral aperture or side port.

[0025] In some embodiments of the medical device, the elongate member has a substantially round cross-section.

[0026] In some embodiments of the first broad aspect, the elongate member of the medical device comprises a coil. In alternative embodiments, the elongate member comprises a braided material.

[0027] In some embodiments of the first, second, and third broad aspects of the invention, the functional tip includes a hemispherical portion. In alternative embodiments, the functional tip has a pointed portion. In other alternative embodiments, the functional tip has a knife-shaped portion.

[0028] In some embodiments of the first broad aspect, the imaging marker is an echogenic marker. In some embodiments, the imaging marker is a magnetic marker (i.e., a marker that is visible using magnetic resonance imaging).

[0029] In some embodiments of the fourth aspect of the invention, the elongate member defines a lumen, the medical device has at least one opening from the lumen to an environment external to the elongate member, and the method further includes using a fluid to sense pressure. In some such embodiments, the fluid includes a liquid. In alternative embodiments, the fluid includes a gas. In another alternative, the fluid includes flowable solid particles, which may be echogenic marker beads.

[0030] In some embodiments of the first and second broad aspects of the present invention, the radiopaque material of the functional tip is selected from the group consisting of platinum, iridium, gold, palladium, tungsten, or alloys thereof. In some embodiments, the radiopaque material is comprised of about 90% platinum and about 10% iridium. In alternative embodiments, the radiopaque material is comprised of about 92% platinum and about 8% tungsten.

[0031] Some embodiments of the first broad aspect include an imaging marker that is a hollow ring-shaped band. Alternative embodiments include coil, disk-shaped, rectangular, elongated imaging markers that define other geometric shapes or define other symbols.

[0032] Some embodiments of the first and second broad aspects of the invention include radiopaque markers that are ring-shaped hollow bands. Alternative embodiments include radiopaque markers that are coils.

[0033] Some embodiments of the second broad aspect of the invention include a channel in an outer wall of the elongate member, the channel containing a radiopaque marker and a filler material. The filler material and the outer wall of the elongate member can define an outer diameter. The filler material can be a polymer suitable for filling spaces or gaps.

[0034] In some embodiments of the second broad aspect, the radiopaque marker can be located at the distal end of the metal tube.

[0035] For some embodiments of the second broad aspect, the radiopaque marker is an anchoring element constrained by a groove (or channel) that prevents the radiopaque marker from being carried away by flowing fluid while allowing the radiopaque marker to move a limited distance within the groove. In alternative embodiments, the end piece holds the radiopaque marker in place. In other alternative embodiments, the elongate member is comprised of a first elongate member component and a second elongate member component, and the first elongate member component and the second elongate member component together hold the radiopaque marker in place.

[0036] In some embodiments of the third broad aspect, the radiopaque marker attached (bonded) to the wall of the tube has rounded ends to reduce turbulence compared to markers with non-rounded ends, thereby minimizing obstruction of fluid flow. In alternative embodiments, the radiopaque marker is comprised of a deposited material (i.e., a material deposited on the interior surface of the elongate member). In some such embodiments, the radiopaque marker is comprised of a material that is spray-deposited to form a deposited layer marker.

[0037] Some embodiments of the third broad aspect of the invention include a radiopaque marker comprised of a plurality of transverse elements that define a grid, a screen, a cross-shaped marker, or an asterisk-shaped marker.

[0038] In some embodiments of the third broad aspect, the radiopaque marker comprises a pair of internal retainers attached to the interior surface of the wall of the metal tube, defining a channel that prevents the radiopaque anchoring element from being carried away by flowing fluid, while allowing the radiopaque anchoring element to move a limited distance within the channel.

[0039] In some embodiments of the first broad aspect of the invention, the imaging marker is embedded in the inner wall of the elongate member at the imaging marker location, and the diameter of the lumen at the imaging marker location is equal to or greater than the diameter of the lumen adjacent the imaging marker. Alternative embodiments include an imaging marker embedded in the outer wall of the elongate member, and the outer diameter of the medical device is not increased by the imaging marker.

[0040] Some embodiments of the first broad aspect include at least one lateral aperture (side port) from the lumen to the environment external to the elongate member. Some such embodiments have an outer insulating layer that slightly overlaps the lateral aperture (side port) of the elongate member.

[0041] In some embodiments of the first broad aspect, the functional tip has an electrode with a diameter equal to or less than the outer diameter of the elongate member.

[0042] In some embodiments of the second broad aspect, the functional tip is operable to transmit electrical energy.

[0043] In some embodiments of the third broad aspect, the radiopaque marker is attached to the metal tube by welding. In some embodiments, the functional tip has radiopaque material fused to the distal end of the metal tube. In some embodiments, the functional tip has radiopaque material and defines the radiopaque marker of the functional tip. In some embodiments, the functional tip has at least a dome-shaped portion.

[0044] In a fifth broad aspect, embodiments of the invention include a medical device comprising: a metallic elongate member having a proximal end and a distal end, the elongate member defining a lumen extending substantially between the proximal and distal ends, and defining at least one opening from the lumen; and an imaging marker associated with the elongate member at a marker location, the imaging marker configured such that, in use, fluid flow through the lumen is substantially unobstructed by the imaging marker, wherein an outer diameter of the device at the marker location is substantially equal to an outer diameter of the device adjacent the marker location.

[0045] In a sixth broad aspect, an embodiment of the invention comprises a medical device including: an elongate member having a proximal end, a distal end, and a metal tube defining a lumen extending substantially between the proximal and distal ends and defining at least one opening / aperture from the lumen; and a pair of internal retainers coupled to an inner surface of a wall of the elongate member and defining a channel for receiving a radiopaque anchoring element, the internal retainers preventing the radiopaque anchoring element from being carried away by fluid flowing within the lumen while allowing the radiopaque anchoring element to move a limited distance within the channel.

[0046] In alternative embodiments of the medical device, the imaging marker may be an echogenic marker, a magnetic marker (i.e., a marker visible using magnetic resonance imaging), or some other type of imaging marker. Thus, while some of the embodiments of the present disclosure are described as having a radiopaque marker, the radiopaque marker may be replaced with or supplemented by an echogenic marker, a magnetic marker (i.e., a marker visible using magnetic resonance imaging), or other types of markers, thereby resulting in alternative embodiments. Furthermore, while the end of the functional tip is shown as dome-shaped in some of the drawings, it may have other shapes, including, but not limited to, a pointed or knife-like shape.

[0047] Referring now specifically to the drawings, it is emphasized that the matter shown is by way of example and for purposes of describing certain embodiments of the invention only. Before describing embodiments of the invention in detail, it is to be understood that the invention is not limited in its application to the precise construction and arrangement of 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. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

[0048] For purposes of this description, proximal refers to next to or close to the user, and distal refers to far from the user. Additionally, alternative terminology is used throughout this specification, generally indicated by the use of regular parentheses, e.g., (). Additionally, while some embodiments have been described in conjunction with metals, metallic tubing, and the like, it should be noted that other materials exhibiting similar material properties, e.g., electrical conductivity, are also included.

[0049] FIG. 1 illustrates one possible general embodiment of an instrument 20. The instrument includes a handle 1, a shaft or elongated member 2, and a distal portion 4 of the elongated member 2. A functional tip having an electrode 3 is associated with the distal tip of the distal portion 4. The electrode 3 is operable to transmit energy. The embodiment of FIG. 1 has a dome-shaped electrode 3, but alternative embodiments may have electrodes 3 of different shapes, such as (but not limited to) pointed or knife-like. The internal details of the elongated member 2 of FIG. 1 may vary. An example of the elongated member 2 of FIG. 1 may include a plastic shaft containing wires connected to the distal electrode 3. Additionally, an alternative example of the elongated member 2 of FIG. 1 may include a conductive metal tube coated with an electrical insulation material. In yet other alternative embodiments, the elongated member 2 may include a coil, braid, or non-round conduit. The portion of the instrument that is typically inserted into a patient (the usable portion of the instrument) generally includes (but is not limited to) the elongated member 2 and the functional tip. Embodiments of the present disclosure include a lumen for fluid flow within the elongate member 2, allowing fluid to be delivered or removed through the lumen (or conduit), or used for pressure sensing. The fluid may be a gas, a liquid, or a solid particle that can flow. Echogenic marker beads are an example of a solid particle that can flow. Electrodes at the distal tip are an optional feature of the present invention and are not found in some alternative embodiments.

[0050] Referring to FIG. 5 , a possible embodiment of the present invention includes an elongate member 2 constructed from a metal tube 8 electrically connected to a metal end member 10. An insulating layer 5, which may be constructed from PTFE (polytetrafluoroethylene), covers the metal tube 8 and a portion of the end member 10, leaving a distal portion of the metal end member 10 exposed to define an electrode 3. The metal tube 8 and metal end member 10 may be constructed from, but are not limited to, stainless steel. The distal end of the end member 10 includes a functional tip 15 including the electrode 3 and a radiopaque marker 6 described above. A possible method for creating the functional tip 15 includes inserting a radiopaque filler (or other radiopaque material) into the distal end of the end member 10, followed by fusing the distal end to close off the lumen 9 at the end of the end member 10. The radiopaque filler may be platinum, iridium, gold-palladium, tungsten, or other radiopaque metals or alloys thereof, such as an alloy of about 90% platinum and about 10% iridium, or about 92% platinum and about 8% tungsten. The portion of the functional tip 15 that extends beyond the insulating layer 5 serves as the electrode 3. The radiopaque portion of the fused material forms the radiopaque marker 6. Depending on how far the insulating layer 5 extends along the distal portion 4, the insulating layer may cover some, all, or none of the radiopaque marker 6. Thus, the electrode 3 may include some, all, or none of the radiopaque marker 6. The metal composition within the fusion weld may vary depending on several factors related to the welding process. Some (but not all) of the factors include: the amount and type of radiopaque filler used to make the weld, the thickness and type of metal of the end member 10, the duration for which energy is applied to the material, and the energy level.

[0051] This embodiment also includes a lumen 9 and a lateral aperture (side port opening) 7 for fluid movement between the lumen and the environment outside the device. Lumen 9 is blocked (or closed) at the distal end of end member 10 by a functional tip 15. Opening 7 is closer to the proximal end of elongate member 2 than functional tip 15, such that functional tip 15 does not obstruct fluid flow through opening 7. Electricity can be supplied to electrode 3 through metal tube 8 and end member 10.

[0052] The embodiment of Figure 5 is an example of an embodiment of the invention having an imaging marker distal to the opening (exit port) through which fluid can enter and exit the device lumen. Other examples of embodiments having this feature are shown in Figures 2a-2d. In Figure 2a, the direction of potential fluid flow within lumen 9 is indicated by flow arrow f. Imaging marker 6 is attached (coupled) to the interior of elongate member 2 distal to opening (side port) 7. The distal end of lumen 9 (not shown) is closed by any of a variety of possible means. Imaging marker 6 may be of various shapes, including, but not limited to, a ring-shaped hollow band or coil. Elongate member 2 may be constructed of plastic, other polymers, metal, or other materials.

[0053] FIG. 2b is a schematic side view illustrating a functional tip 15 including an imaging marker 6 attached (coupled) to the end of the distal portion 4 of the elongate member 2, thereby blocking or occluding the lumen 9. The embodiment shown in FIG. 2b may have a shaft of the distal portion 4 constructed of one or more layers / components of plastic, other polymers, metal, or other materials. The imaging marker 6 may be radiopaque, echogenic, magnetic (i.e., visible using magnetic resonance imaging), or another type of marker. The marker 6 is distal to the opening 7, allowing fluid to exit the opening 7 without being obstructed by the marker 6. The embodiments of FIGS. 2a and 2b having a metal shaft generally have an insulating layer 5 (not shown) on the upper side of the shaft in the medical device 20.

[0054] 2c shows an embodiment in which the distal portion 4 is constructed from a plastic tube. A functional tip 15 closes the lumen 9 at the end of the distal portion 4. An insulated electrical conductor 11 is connected to the functional tip 15, thereby enabling energy to be transmitted to the electrode 3. The functional tip 15 (including the marker 6) can be attached to the shaft of the distal portion 4 using a number of methods, including, for example, but not limited to, adhesive bonding or engagement of mating threads. The lumen 9 can also contain wires for different purposes, such as fiber optic wires or wires for use in pressure sensing.

[0055] 2d shows an embodiment with a distal portion 4 comprising a metal tube and an insulating layer 5. The lumen 9 is closed by a fused functional tip 15 with an end marker 6. The marker 6 is distal to a lateral aperture (side port opening) 7. The fusion weld in this embodiment has an alternative weld shape to the embodiment of FIG.

[0056] Figures 10a-10d show several views of additional embodiments similar to that of Figure 2d, including electrodes 3 and markers 6, apertures 7, lumens 9, and insulating layers 5 of a functional tip 15.

[0057] Figures 11a-11g show another embodiment similar to that of Figure 2d, including an elongated member 2, an electrode 3, an insulating layer 5, an aperture 7, a metal tube 12, and a functional tip 15. The broken and dashed lines in these figures indicate the indeterminate length of the device. Figures 11a and 11b show that in this embodiment, the insulating layer 5 slightly overlaps the metal tube 12 around the lateral aperture 7 (side port 7). Overlapping the insulating layer 5 over the metal tube 12 prevents the metal at the aperture 7 from being exposed, thereby preventing the conductive metal from contacting the surrounding tissue. The overlap also reduces leakage current through the aperture 7. Figure 7 shows a longitudinally elongated lateral aperture 7, which enhances fluid flow compared to a round aperture having a diameter similar to the height of the elongated lateral aperture 7 (i.e., a smaller diameter).

[0058] The embodiments seen in Figures 3a-3i are examples of embodiments of the present invention in which radiographic markings are embedded in the wall of the elongated member. Figure 3a is an example of an embodiment in which the marker 6 is embedded in the interior surface of the wall of the elongated member 2, thereby allowing fluid to flow unimpeded through the lumen 9 and not increasing the outer diameter of the elongated member 2. The marker 6 may be embedded in the interior wall using different techniques, such as overmolding. Figure 3b is an example of an embodiment in which the marker 6 is embedded in the exterior wall of the elongated member 2, allowing fluid to flow unimpeded through the lumen 9 and not increasing the outer diameter of the elongated member 2. The radiographic marker 6 may be of different shapes, including, but not limited to, a ring-shaped hollow band or coil. Alternative embodiments include disk-shaped, rectangular, and elongated radiographic markers defining other geometric shapes or defining symbols.

[0059] In the embodiment of Figures 3a and 3b, the elongated member 2 may be composed of one or more layers / components of plastic, other polymers, metal, or other materials. The marker is embedded in a wall, which may be all metal or substantially (mostly) metal. For example, the wall containing the marker may be coated with a relatively thin layer of polymer, such as the wall of Figure 3b, which is coated with a layer of electrical insulation. Because all metals are radiopaque to some extent, the radiopaque marker must be more radiopaque than a metal tube to function properly. Generally, in any embodiment of a device having a radiopaque marker, the radiopaque marker may be composed of a material that is more radiopaque than any material comprising the elongated member 2. In Figures 3a and 3b, the distal end of the lumen 9 is open. The embodiment of Figures 3a and 3b having a metal shaft may optionally have an insulating layer 5 (not shown).

[0060] FIG. 3j is an example of an embodiment similar to FIG. 3b, but similarly includes a marker 6 embedded in the outer wall of the elongate member 2, allowing fluid to flow unimpeded through the lumen 9. In the embodiment of FIG. 3j, the marker 6 is inside a groove (or channel) 25. If the space in the channel 25 is larger than the space required for the marker 6, a filler 26 can be used to fill the excess space and create a consistent outer diameter. The groove (or channel) 25 is cut into the elongate member 2, and when the marker 6 is placed therein, the filler 26 can smooth the contour of the outer diameter. The filler can be a polymer suitable for filling spaces or gaps.

[0061] One method of making the embodiment of Figure 3j involves the following steps: 1) selectively reducing the outer surface of the wall of the substrate tube (e.g., HDPE - high density polyethylene) using a process such as centerless grinding, thereby defining grooves (or channels) 25; 2) placing the substrate tube on a metal mandrel to retain and support the lumen; 3) crimping thin-walled Pt (platinum) band markers 6 onto the substrate tube and into channels 25; 4) incorporating filler 26 material (e.g., Tecoflex®) by reflowing it into the remaining space of grooves (or channels) 25 (optionally incorporating filler 26 using heat shrink); and 5) removing the assembly from the mandrel and removing the heat shrink, if used. The heat shrink may help ensure that the outer dimensions of the device at the marker location are the same as the outer dimensions of the device adjacent to the marker.

[0062] Alternatively, other materials can be used in the embodiment of Figure 3j, for example, elongate member 2 may be constructed of metal and band marker 6 may be constructed of a radiopaque polymeric material that may be stretched and incorporated into grooves (or channels) 25.

[0063] Figures 3c and 3d show embodiments in which the marker 6 is embedded in a metal tube 12 having a closed end. The elongate member also has an insulating layer 5. Figure 3c shows a metal tube 12 including the tube sidewall and distal end enclosure, which is continuous (i.e., not a separate component) and has a substantially constant thickness, e.g., a hypotube. Figure 3d shows a metal tube 12 closed by fusion welding. In both Figures 3c and 3d, the embedded internal marker 6 does not obstruct fluid flow through the opening (side port) 7. The embodiment of Figure 3d has both an internal lumen marker 6 and an end marker 6.

[0064] Figures 3e and 3f show embodiments that are similar to the corresponding embodiments of Figures 3a and 3b, respectively, except that the embodiments of Figures 3e and 3f have a marker 6 embedded in the distal end of the shaft or elongate member 2.

[0065] FIG. 3g has an internal marker 6 that is not fixedly attached to the surface of the wall defining the lumen 9, but instead is capable of limited movement relative to the wall. At least a portion of the marker 6 is contained within a groove (or channel) 25 in the interior surface of the wall of the elongate member 2. The marker 6 is capable of moving a limited distance within the groove 25 with fluid passing through the lumen 9. In this embodiment, the marker 6 may be referred to as an anchoring element marker because the groove 25 prevents it from being carried away by the flowing fluid. As with the previous embodiment, the elongate member 2 may have different layers and components, including, for example, a metal coated with an insulating material.

[0066] Figure 3h shows an embodiment similar to that of Figure 3e with the addition of an end piece 21. The end piece 21 may hold the marker 6 in place and / or the marker 6 may be held in place by alternative means, such as, for example, welding or gluing. The end piece 21 may also have additional / alternative functions, such as, for example, providing a smooth end surface.

[0067] FIG. 3i discloses an embodiment that adds a second component 22 of the elongate member. The second component 22 may connect to the first component of the elongate member 2 and hold the marker 6 in place, and / or the marker 6 may be held in place by alternative means, such as welding or adhesive. In some embodiments, the second component 22 may be an extension to a larger first portion of the elongate member 2. In other embodiments, the second component 22 may be a second portion of the elongate member 2, where the elongate member 2 has a portion of comparable size to (or perhaps smaller than) the first or second component 22.

[0068] Alternative embodiments of Figures 3a-3i may have other types of imaging markers, such as echogenic markers or magnetic markers (i.e., markers visible using magnetic resonance imaging), in addition to or instead of radiopaque markers, for use with appropriate types of imaging systems and techniques.

[0069] The embodiments shown in Figures 4a-4e are examples of embodiments of the present invention described below. In these embodiments, the radiographic marker is attached (bonded) to the inner surface of the elongate member wall (which may be a metallic tube) and minimally affects or obstructs fluid flow within the lumen 9. The elongate member 2, including the distal portion 4, may be composed of one or more layers / components of plastic, other polymers, metal, or other materials. Embodiments having a metal shaft may have an insulating layer 5. Figure 4a is an example of an embodiment in which a ring-shaped band marker 6 is bonded to the inner wall of the elongate member 2, thereby allowing fluid to flow through the lumen 9 and not increasing the outer diameter of the elongate member. The lumen diameter is reduced only over a relatively short length of the lumen where the band marker 6 is present. The rounded end 13 of the marker can reduce turbulence, thereby minimizing obstruction to fluid flow. In an alternative embodiment, the marker 6 may be a coil. The distal end of the lumen 9 is open in the embodiments of Figures 4a and 4b. For purposes of illustration, the markers are shown in this illustration as being thicker (relative to the elongate members) than would be required in an actual embodiment.

[0070] The embodiment of FIG. 4a may be contrasted with the case where a marker is added to the outer surface of the shaft. When a marker is attached to the outer surface of the shaft, in order to maintain the same outer device diameter at the marker attachment location, the outer diameter size of the shaft must be reduced to compensate for the thickness of the marker, thereby reducing the lumen diameter and impeding fluid flow. A hypothetical example may illustrate this point. If a hypothetical shaft has an outer diameter of 10 units and a wall thickness of 1 unit, the lumen diameter will be 8 units. If a marker band with a thickness of 1 unit is attached to the outside (without bending or crimping the shaft), maintaining the same overall outer diameter of 10 units (to allow the device to be advanced through certain passageways, such as body vessels) would require reducing the outer diameter of the shaft to 8 units and the lumen diameter to 6 units over the entire length of the shaft (using common manufacturing practices), thereby significantly reducing the amount of fluid that can flow through the lumen at a given pressure. Advantageously, incorporating a marker band of one unit thickness within the lumen of the shaft, as in the embodiment described above, reduces the diameter of the lumen to six units over only a portion of the length of the marker band (i.e., a relatively short distance), but has much less impact on the volume of fluid flowing at a given pressure compared to reducing the lumen diameter over the entire length of the shaft.

[0071] Figure 4b is an example of an embodiment in which the marker is comprised of a material deposited on the interior wall surface of the elongate member 2 by a method such as spray deposition to form a deposited layer marker 14. As with the embodiment of Figure 4a, the deposited layer marker 14 allows fluid to flow through the lumen 9 without significantly obstructing it, and does not increase the outer diameter of the elongate member 2. Other methods of depositing material inside the lumen include electroplating and sputter deposition (physical vapor deposition) of radiopaque materials onto the interior surface (which defines the lumen), which creates an internal band marker or interior surface.

[0072] The embodiment of Figure 4c shows a marker 6 bonded to the inner wall of a closed-ended metal tube 12. Fluid can flow through the lumen 9 and out the opening (exit port) 7 without being significantly impeded by the marker, and the outer diameter of the elongate member 2 does not increase.

[0073] Figure 4d shows a marker 6 attached to the inner wall of the distal portion 4 and a functional tip 15 that closes (or blocks) the lumen 9 at the end of the distal portion 4. Fluid can flow through the lumen 9 and out the opening 7 without significant obstruction, and the outer diameter of the elongate member 2 does not increase. The functional tip 15 of the embodiment of Figure 4d may or may not include a marker. Any of the embodiments of Figures 4a-4e can be modified so that the markers 6 or 14 are partially embedded in the wall of the device, while some markers are not.

[0074] FIG. 4e discloses an embodiment comprising a marker 6 including multiple transverse elements disposed within the lumen of the device. While the embodiment of FIG. 4e shows the marker 6 as a grid, in alternative embodiments, the marker 6 may comprise a screen, a cross-shaped marker (i.e., two linear blocking elements), an asterisk-shaped marker, or other configurations having multiple transverse elements. The transverse elements allow fluid to flow through the lumen while being visible in images in clear distinction from the rest of the medical device 20. For this embodiment, the marker 6 may be either attached to or at least partially embedded in the surface of the interior wall of the elongate member 2.

[0075] Figure 4f illustrates a device that includes an internal marker 6 that is not fixedly attached to the surface of the wall defining the lumen 9, but instead is capable of limited movement relative to the wall. The marker 6 is constrained by a pair of internal retainers 24 that are attached to the inner surface of the wall of the elongate member 2. The marker 6 is capable of moving a limited distance between the internal retainers 24 due to fluid passing through the lumen 9. Although Figure 4f illustrates the internal retainers 24 as separate parts attached to the surface of the wall, in alternative embodiments, the internal retainers 24 can be integrally formed with and protrude from the wall.

[0076] 6a and 6b show the positioning of the marker 6 within the lumen 9 and one or more joints 19 that secure the marker 6 in place within the lumen of the tubular component 16. The marker 6 can be secured in place using a variety of means, including: - welding by heating the outer surface of the tubular component 16, - adhesives or epoxies, - mechanical deformation (crimping) of the outer surface covering the tubular component 16 or near the band, - internal welding (with a very small welding machine, or a fiber optic laser welding system), - interference fitting (forcing an oversized ring-shaped band marker 6 into place), - shrink fitting (expanding the outer tube (tubular component 16) with heat and shrinking the inner band marker 6 by cooling, sliding the band marker into place and allowing the outer tube to cool while the inner band marker warms up), - external / internal magnets with compatible material, and - by threading the inner diameter of the tube and the outer diameter of the inner component (parallel to the axis of the tube) and then threading.

[0077] Figures 7 and 8 illustrate the fusion welding method for fabricating the end markers of some embodiments. Figure 7 shows the basic components before welding. Figures 7a and 7b show side and end views of an embodiment using a hollow marker 17 as a filler at the end of the lumen of a tubular component 16. Figures 7c and 7d show side and end views of another embodiment using a solid marker 18 as a filler at the end of the lumen of another tubular component 16. If the filler material is used as a radiopaque marker, it must be more radiopaque than the material of the tubular component 16 to which it is bonded. Figure 8 shows the device after welding, and Figures 8a and 8b show side and end views of a functional tip 15 having a fusion weld formed from the hollow marker 17 of Figure 7a and the end of the tubular component 16. 8c and 8d show side and end views of a functional tip 15 having a fusion weld formed from the solid marker 18 of FIG. 7c and the end of the tubular component 16. A laser may be used to deliver energy to create the dome-shaped functional tip 15. The configuration of the final fusion weld may vary depending on a number of welding factors, some of which include: the amount and type of radiopaque filler, the thickness and type of metal of the tubular component 16, the welding time, and the energy intensity.

[0078] The basic component configurations shown in Figures 6-8 should not be construed as limiting the scope of the present invention, as other configurations are possible. For example, embodiments may have a sharp or blunt pointed tip or a knife tip, or may have an internal hollow marker located at the distal end of the lumen, or the end is not a welded closure.

[0079] Some possible options for the above-described fusion welding process include the tubular component 16 being made of a different material (plastic, metal, etc.), which can be a filler. Prior to welding, the filler can have a different shape and does not have to fit snugly to the inner diameter of the tubular component 16. The filler can be a single piece or part, or multiple pieces or parts, with the multiple pieces or parts containing particles as small as a powder.

[0080] The medical device of the present disclosure may be used with a radio frequency (RF) energy source to form a channel at a target location in a patient's body. One such embodiment includes the steps of: a) introducing a medical device 20 having an elongated member 2 and a functional tip 15 at its distal end into the patient's vasculature, b) advancing the elongated member 2 through the vasculature using the radiopaque marker 6 of the functional tip 15 for imaging, thereby steering the functional tip 15 (having electrodes 3), c) positioning the electrodes 3 of the functional tip 15 (operable to transmit energy) at the target location, and d) transmitting electrical energy through the electrodes 3 to form a channel.

[0081] An aperture 7 can be used to deliver fluid from the lumen 9 of the elongate member 2 to the target location. In some embodiments, having the distal end of the lumen 9 closed by a functional tip 15 and having the aperture 7 (as in FIG. 5 ) be a side port helps avoid coring of tissue. This embodiment includes a functional tip 15 with a diameter smaller than the outer diameter of the elongate member, facilitating or encouraging advancement of the elongate member through the vasculature; i.e., the functional tip does not increase the outer diameter of the device, which would make advancement more difficult. Optionally, the energy delivered to the target location may be radio frequency electrical energy. In an alternative embodiment, the functional tip 15 may have a portion visible under alternative medical imaging modalities, such as ultrasound or magnetic resonance.

[0082] In one specific embodiment of a method of using the disclosed medical device, the target site may include tissue within a patient's heart, such as the atrial septum of the heart, as shown in Figures 9A and 9B. In such an embodiment, the target site is accessed via the inferior vena cava (IVC), for example, through the femoral vein, and said access may be facilitated by imaging markers 6 on the functional tip 15 during advancement of the medical device 20 (or radiofrequency perforation apparatus 20). This embodiment includes providing a medical device 20 including a functional tip 15 that is visible on an image and that is visually distinct from the rest of the medical device.

[0083] In one such embodiment, a contemplated user introduces a guidewire into the femoral vein, typically the right femoral vein, and advances it toward the heart. A guiding sheath 30, such as that described in U.S. patent application Ser. No. 10 / 666,288 (filed Sep. 10, 2003), which is incorporated herein by reference in its entirety, is then introduced into the femoral vein over the guidewire and advanced toward the heart. The distal end of the guidewire and sheath 30 are then positioned in the superior vena cava. These steps may be performed with the aid of an imaging system appropriate for the markers 6. Once the sheath 30 is in place, a dilator 28, such as the TorFlex™ Transseptal Dilator (Baylis A dilator, such as that described in U.S. Pat. No. 11 / 727,382 (filed March 26, 2007), or U.S. Pat. App. No. 11 / 727,382 (filed March 26, 2007), which is incorporated herein by reference in its entirety, is introduced over the guidewire with the sheath 30 and advanced through the sheath into the superior vena cava. The sheath 30 can help prevent the dilator 28 from damaging or perforating the vessel wall, for example, in embodiments including a substantially rigid dilator. Alternatively, the dilator 28 may be fully inserted into the sheath 30 before entering the body, allowing them to be advanced simultaneously to the heart. Once the guidewire, sheath 30, and dilator 28 are positioned in the superior vena cava, the guidewire is removed from the body, and the sheath and dilator are slightly retracted so that they enter the right atrium of the heart. An electrosurgical instrument, such as the radio frequency perforation device 20 described above, is then introduced into the lumen of the dilator and advanced toward the heart.

[0084] In this embodiment, after inserting the electrosurgical device into the dilator 28, the user may position the distal end of the dilator against the atrial septum 32. The image of the markers 6 on the functional tip 15 is then used to position the electrosurgical device so that the electrode 3 is aligned with or slightly protruding from the distal end of the dilator 28, but is not retracted into the dilator. The dilator 28 and medical device 20 are dragged along the atrial septum 32 using the image of the markers 6 on the functional tip 15, for example, to position it relative to the fossa ovalis of the atrial septum. Various additional steps may be performed, such as measuring one or more characteristics of the target site or delivering a material to the target site, such as electrogram or ECG (electrocardiogram) tracings and / or pressure measurements, or delivering a contrast agent through one or more apertures 7 and / or the open distal end. Such a step may help localize the electrode 3 to the desired target site. Additionally, tactile feedback provided by the medical device 20 (radiofrequency perforation device 20) can be used to facilitate positioning of the electrode 3 at the desired target site. The surgeon can visually monitor the position of the functional tip 15 as it is advanced upward into the heart and as it is dragged along the surface of the interatrial septum 32 and positioned in the groove of the fossa ovalis.

[0085] Using the electrosurgical instrument and a dilator positioned at the target site, energy is delivered from an energy source through the medical instrument 20 (radiofrequency perforation device 20) to the target site. For example, when the radiofrequency perforation device 20 is used, energy is delivered through the elongate member 2 to the electrode 3 and into the tissue at the target site. In some embodiments, the energy is delivered at a voltage of at least about 75 V (peak-to-peak) and a power of at least about 5 W, and functions to vaporize cells near the electrode, thereby forming voids or perforations through the tissue at the target site. When the heart is reached via the inferior vena cava as described above, the user applies force to the handle 1 of the electrosurgical instrument in a substantially cranial direction as energy is being delivered. The force is then transferred from the handle to the distal portion 4 of the radiofrequency perforation device 20, advancing the distal portion 4 at least partially through the perforation. In these embodiments, energy delivery is stopped once the distal portion 4 has passed through the target tissue, i.e., when it reaches the left atrium. In some embodiments, the step of transmitting energy occurs over a period of about 1 second to about 5 seconds.

[0086] Some embodiments of methods of using the disclosed medical device include using a medical device 20 with a functional tip 15 that is substantially visible within a radiopaque dilator. The functional tip 15 includes a tip marker 6 that is sufficiently radiopaque to be visible under fluoroscopy. The medical device 20 may be used with a radiopaque dilator that is visible under fluoroscopy, but the tip marker 6 remains visible while inside it. Substantially most or all of the dilator, or only a distal portion thereof, may be radiopaque. Using the tip marker 6 with such a compliant dilator allows a physician to position the functional tip 15 relative to the end of the dilator. For example, a physician can ensure that the tip of the medical device 20 protrudes from the dilator 28 only at the desired time. By using fluoroscopy to perform a transseptal procedure, the radiopaque dilator can be positioned relative to the septum before crossing, and the physician can maintain the tip of the medical device on the dilator. The functional tip 15 is also visible within the dilator 28, so it can be positioned just inside the tip of the dilator just before crossing the septum. The electrodes 3 of the radiofrequency perforation device 20 only need to extend from the dilator when the physician chooses to cross. The physician can avoid inadvertently extending the functional tip 15 beyond the end of the dilator before it is necessary.

[0087] It is also possible that the radiofrequency drilling device 20 and dilator 28 with a radiopaque tip can be used with a catheter equipped with a radiopaque marker at the tip to enhance visibility and allow the physician better control.

[0088] As explained above, medical devices are disclosed that provide improved visualization of a portion of the medical device insertable into a patient's body while minimizing obstruction of fluid flow through the device's lumen and minimizing an increase in the device's outer diameter due to the features that provide the improved visualization. The device may include, for example, an imaging marker distal to the opening (exit port) of the lumen, or, if the device includes a tube, e.g., a metallic tube, the imaging marker is embedded in the wall of the tube. Alternative embodiments include attaching a marker to the inner surface of the medical device's lumen without substantially embedding the marker. Various alternative embodiments, methods, and applications of using such devices are also disclosed.

[0089] Additional details regarding the devices and methods not described herein can be found in U.S. patent application Ser. No. 11 / 905,447, filed Oct. 1, 2007; U.S. patent application Ser. No. 13 / 113,326, filed May 23, 2007; U.S. patent application Ser. No. 11 / 265,304, filed Nov. 3, 2005 (now U.S. Patent No. 7,947,040); U.S. patent application Ser. No. 11 / 265,304, filed Sep. 19, 2003 (now U.S. Patent No. 7,947,040); No. 10 / 666,301, filed January 21, 2004 (now issued as U.S. Patent No. 7,048,733), U.S. Patent Application No. 10 / 760,479, filed January 21, 2004 (now issued as U.S. Patent No. 7,270,662), U.S. Patent Application No. 10 / 666,288, filed September 19, 2003, U.S. Patent Application No. 10 / 347,366, filed January 21, 2003 (now issued as U.S. Patent No. 7,112,197), U.S. Provisional Patent Application No. 60 / 522,753, filed November 3, 2004, and U.S. Provisional Patent Application Nos. 60 / 884,285, filed January 10, 2007 and 60 / 827,452, filed September 29, 2006. The contents of all of the above-mentioned applications and patents are incorporated herein by reference in their entirety.

[0090] The above-described embodiments of the present invention are exemplary only, and the scope of the present invention is therefore intended to be limited only by the appended claims.

[0091] It will be appreciated that certain features of the invention which 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 which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.

[0092] While the present invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, it is 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 herein are herein incorporated by reference in their entirety to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference herein. Furthermore, citation or identification of any reference herein shall not be construed as an admission that such reference is available as prior art to the present invention.

Claims

1. A medical device for forming a perforation in tissue of the cardiac septum, comprising: an elongate member including a metallic tubular member having a proximal end and a distal end and defining a lumen extending substantially between said proximal end and said distal end; and an electrically insulating layer covering said metallic tubular member; an atraumatic tip located at the distal end of the elongate member, defining a closed distal end, operable as an electrode for delivering energy to tissue, and including a radiopaque imaging marker; a lateral side port in fluid communication with the lumen of the elongate member and disposed proximal to the closed distal end; A medical device comprising:

2. A medical device as described in claim 1, wherein the atraumatic tip is dome-shaped or hemispherical.

3. A medical device as described in claim 1 or 2, further comprising a second lateral side port.

4. A medical device as described in claim 3, wherein the lateral side port extends longitudinally.

5. A medical device as described in claim 3, wherein the entire X-ray opaque imaging marker is electrically exposed.

6. A medical device as described in claim 3, wherein a distal portion of the elongated member proximal to and adjacent to the atraumatic tip has a constant outer diameter.

7. The medical device of claim 3, wherein the first diameter of the atraumatic tip is equal to or less than the second diameter of the elongated member.

8. A medical device described in any one of claims 4 to 7, further comprising an insulating layer at least partially overlapping the lateral side port.

9. A system for forming a perforation in tissue of a cardiac septum, comprising: The medical device of claim 1; an electrosurgical generator operable to provide energy to the atraumatic tip; A system comprising:

Images