Apparatus and methods for placing leads using direct visualization

An apparatus for imaging a body structure within a body cavity includes a catheter including proximal and distal ends, an imaging element on the distal end, and an extension extending distally from the distal end for contacting a surface of a body cavity into which the catheter is introduced. The extension has a length to maintain the optical imaging element away from the surface. Optionally, a transparent member, e.g., an expandable balloon, may be attached to the distal end of the tubular member and the extension to isolate the imaging element from contact with fluid within the body cavity. During use, the catheter is inserted into a chamber of a beating heart, and the extension and/or balloon is placed against the wall of the chamber. Sufficient force is applied to stabilize the imaging element relative to the wall while the heart is beating.

FIELD OF THE INVENTION

The present invention relates generally to apparatus and methods for delivering leads into a patient's body, and, more particularly, to apparatus and methods for delivering leads within body lumens of a heart and/to epicardial locations under direct visualization.

BACKGROUND

Minimally invasive procedures have been implemented in a variety of medical settings, e.g., for vascular interventions, such as angioplasty, stenting, embolic protection, electrical heart stimulation, heart mapping and visualization, and the like. One such procedure involves delivering an electrical lead into a coronary vein of a patient's heart that may be used to electrically stimulate the heart.

During such procedures, instruments, fluids, and/or medicaments may be delivered within a patient's vasculature using visualization tools, such as x-ray, fluoroscopy, ultrasound imaging, endoscopy, and the like. In many procedures, it may be desired to deliver instruments through opaque fluids, such as blood, or other materials. Endoscopes have been suggested that include devices for displacing these materials from an optical path, e.g., by introducing a clear fluid from the endoscope in an attempt to clear its field of view. Yet there are still improvements that may be made to such devices.

Accordingly, apparatus and methods for imaging within body lumens and/or for delivering instruments and/or fluids into a patient's body would be useful.

SUMMARY OF THE INVENTION

The present invention is directed to apparatus and methods for delivering leads into a patient's body, and, more particularly, to apparatus and methods for securing leads relative to tissue structures and/or body lumens or cavities, and for delivering leads within body lumens of a heart and/to epicardial locations under direct visualization.

In accordance with one aspect of the present invention, a system is provided for delivering a lead into a body cavity of a patient that includes an imaging device, an elongate rail, and a lead. The imaging device may include a proximal end, a distal end sized for introduction into a body cavity. The elongate rail may include a proximal end, a distal end sized for introduction into a body cavity, and one or more fixation elements on the distal end for securing the distal end to a delivery location within a body cavity. The elongate rail may be sized for introduction through a lumen of the imaging device, e.g., a guidewire. Alternatively, the elongate rail may be sized to be introduced around the imaging device, e.g., a sheath or other tubular member.

In one embodiment, the lead may include a proximal end, a distal end, and a lumen extending therebetween for receiving the elongate rail therein, such that the lead may be advanced over the elongate rail. In another embodiment, the lead may include a proximal end, and a distal end sized for introduction through a lumen of the elongate rail. The lead may include one or more electrodes on the distal end, e.g., for pacing or other electrical stimulation of the heart.

In accordance with another embodiment, a method is provided for delivering a lead within a body cavity. A distal end of an imaging device may be placed against a wall of a tissue structure adjacent a body cavity, and manipulated relative to the wall of the tissue structure to image and/or otherwise identify a target site. A distal end of an elongate rail may be delivered via the imaging device, e.g., through or over the imaging device, to the target site, and secured relative to the target site. For example, the distal end may include one or more fixation elements for securing the distal end to tissue at the target site.

The imaging catheter may be removed, and then a lead may be advanced via the elongate rail, e.g., over or through the elongate rail, to the target site, and secured relative to the target site. For example, the distal end of the lead may include one or more fixation elements for securing the distal end to tissue at the target site. The elongate rail may remain or may then be removed. In an alternative embodiment, the lead may be secured to the elongate rail, thereby securing the lead relative to the target site.

In accordance with still another embodiment, a method is provided for delivering a lead within a body cavity. An imaging catheter may be introduced through one or more body lumens, and used to identify a delivery location for a lead. A distal end of an elongate rail may be introduced via the imaging catheter to the identified delivery location, and secured at the delivery location. A lead may be delivered via the rail to the delivery location, and secured relative to the delivery location. For example, the delivery location may be a location in the right ventricular septum or at another location within a chamber of a heart.

In accordance with yet another embodiment, a method is provided for delivering a medical device within a body cavity. An imaging device may be introduced into a thoracic cavity adjacent a heart of a patient. A surface of the heart may be imaged using the imaging catheter to identify a delivery location for a lead. A distal end of an elongate rail may be introduced via the imaging catheter to the delivery location, and secured to the delivery location, e.g., to epicardial tissue of the heart. A lead may be delivered via the elongate rail to the delivery location, secured relative to the delivery location.

DETAILED DESCRIPTION

Turning to the drawings,FIGS. 1A-1Cshow a first preferred embodiment of an apparatus10for imaging a body lumen, e.g., for visualizing, accessing, and/or cannulating a body lumen or tissue structure from a body cavity (not shown). In an exemplary embodiment, as explained further below, the apparatus10may be used for imaging a wall of a right atrium of a heart, e.g., for visualizing, accessing, and/or cannulating a coronary sinus ostium, although the apparatus10may be used for visualizing, accessing, and/or cannulating other body lumens and/or tissue structures as well. Generally, as shown inFIG. 1A, the apparatus10may include a catheter or other elongate member12, a balloon or other expandable member50on a distal end16of the catheter12, and an imaging assembly62carried by the distal end16of the catheter12for imaging through the balloon50.

The catheter12generally is an elongate tubular body including a proximal end14, a distal end16having a size and shape for insertion into a patient's body, and a central longitudinal axis18extending between the proximal and distal ends14,16. The catheter12may include one or more lumens20also extending between the proximal and distal ends14,16, e.g., a cannulation lumen20a, an inflation lumen20b, and one or more lumens20c,20d(best seen inFIG. 1C) for the imaging assembly62.

The catheter12may be substantially flexible, semi-rigid, and/or rigid along its length, and may be formed from a variety of materials, including plastic, metal and/or composite materials, as is well known to those skilled in the art. For example, the catheter12may be substantially flexible at the distal end16to facilitate advancement through tortuous anatomy, and/or may be semi-rigid or rigid at the proximal end14to enhance pushability of the catheter12without substantial risk of buckling or kinking.

Preferably, the catheter12is steerable, i.e., the distal end16may be controllably deflected transversely relative to the longitudinal axis18. In the embodiment shown inFIGS. 1A-1C, a single pullwire or other steering element22may be provided, e.g., within one of the lumens20, for steering the distal end16of the catheter12in one transverse plane (thereby providing one degree of freedom). Alternatively, in another embodiment, such as that shown inFIGS. 2A and 2B, two pullwires22′ may be provided for steering the distal end16′ of the catheter12′ in two orthogonal planes (thereby providing two degrees of freedom).

The pullwire(s)22may be a cable, wire, band, and the like that may be slidably disposed within a lumen, such as the inflation lumen20bshown inFIG. 1C. The pullwire(s)22may be attached or otherwise fixed relative to the catheter12at a location adjacent the distal end16, preferably offset radially outwardly from the central axis18. Thus, when the pullwire22is pulled proximally, e.g., from the proximal end14of the catheter12, a bending force may be applied to the distal end16, causing the distal end16to bend transversely relative to the central axis18.

The catheter12may also include a handle or other control mechanism30coupled to or otherwise provided on the proximal end14of the catheter12. The handle30may include one or more steering controls32that may be actuated to steer the distal end16of the catheter12. For example, as shown inFIG. 1, a dial32may be provided that may be coupled to the pullwire22. The dial32may be rotated to apply a proximal force on the pullwire22, thereby bending the distal end16of the catheter12. In a further alternative, the steering control32may include a slider coupled to a pullwire (not shown) such that translation of the slider translates the pullwire, causing deflection of the distal tip of the catheter12as the pullwire is placed in tension or compression. Exemplary embodiments of steering controls are disclosed in application Ser. No. 11/062,074, filed Feb. 17, 2005, the entire disclosure of which is expressly incorporated by reference herein.

The handle30may also include ports and/or other connections for connecting other components to the catheter12. It will be appreciated that any known connectors may be provided for permanently or temporarily connecting components to the catheter12. For example, a luer lock connector may be used to connect tubing or other fluid-conveying components to the handle30.

As shown inFIG. 1A, a syringe or other source of fluid34, e.g., including saline, carbon dioxide, nitrogen, or air, may be connected via tubing36to the inflation lumen20b(not shown, seeFIG. 1C) for inflating the balloon50. In addition or alternatively, a stop-cock or check valve (not shown) may be included in the path of the inflation lumen20bto selectively maintain balloon inflation. For example, a luer-activated check valve may be used, such that a luer-lock syringe34may be engaged with the apparatus10to open the valve for balloon inflation or deflation. When the syringe34is removed, the check valve may automatically close to maintain balloon inflation. The syringe34may also provide a source of vacuum for deflating the balloon50, as is known in the art. Another source of fluid38, e.g., saline, and/or a therapeutic or diagnostic agent, may be connected via tubing40to the cannulation lumen20afor delivering fluid beyond the distal end16of the catheter12.

In addition, an access port42may also communicate with the cannulation lumen20a, e.g., including a hemostatic seal and the like (not shown), for delivering one or more instruments (such as guidewire80, shown inFIG. 1B) through the cannulation lumen20a, as explained further below. Optionally, the handle30may include a shape, size, and/or contour (not shown) for facilitating manipulating the catheter12during use.

Returning toFIGS. 1A and 1B, a substantially transparent balloon50may be provided on the distal end16of the tubular member12. The balloon50may be expandable from a contracted condition (not shown) to an enlarged condition when fluid is introduced into an interior60of the balloon50. In the embodiment shown, a channel52may extend through the balloon50that communicates with a lumen20of the catheter12, e.g., the cannulation lumen20a. Preferably, the channel52extends through the balloon50concentrically with the central axis18, as best seen inFIG. 1B.

In an exemplary embodiment, the balloon50may be formed from substantially noncompliant material, e.g., polytetrafluoroethylene (PTFE), expanded polytetrafluoroethylene (EPTFE), fluorinated ethylenepropylene (FEP), polyethylene teraphathalate (PET), urethane, olefins, and polyethylene (PE), such that the balloon50may expand to a predetermined shape when fully inflated to the enlarged configuration. Preferably, in the enlarged configuration, the balloon50may have a distal surface54that is substantially flat or otherwise configured for contacting a wall of a body cavity, such as the right atrium (not shown). Alternatively, as shown inFIGS. 19A and 19B, an apparatus710may be provided that carries a balloon750having a frustoconical shape and/or a convex distal surface754.

The material may be sufficiently flexible and/or elastic such that the distal surface54may conform substantially to the wall of the body cavity. Preferably, the balloon50is also sufficiently noncompliant to displace blood or other fluid from between the distal surface54and the wall of the body cavity to facilitate imaging the wall through the balloon50, as explained further below. Alternatively, the balloon50may be formed from compliant and/or elastomeric materials, such as silicone, latex, isoprene, and chronoprene.

In the exemplary embodiment shown inFIG. 1B, the balloon50may be formed from one or more panels that may be attached to one another, e.g., using an adhesive (such as an adhesive cured using ultraviolet (“UV”) light), sonic welding, and/or heating, after lapping or butting adjacent panels together. Alternatively, the balloon50may be molded around or within a mold (not shown) having a desired shape for the balloon50in the enlarged condition.

The resulting balloon50may include a proximal end56that may be attached to an outer surface of the catheter12, e.g., using an adhesive, heating, sonic welding, an interference fit, and/or an outer sleeve. The channel52may be formed from the same material as the rest of the balloon50, and a proximal end58of the channel may be attached to the distal end16of the catheter12, e.g., within or concentric with the cannulation lumen20a. Alternatively, the channel may be formed from a semi-rigid or rigid tubular member, as shown inFIGS. 6-10, and described further below.

In another alternative, the channel52may be formed of one or more materials to provide a stiffness transition or multiple transitions. In a further alternative, the channel52may be flexible or semi-flexible, but also biased and/or constrained in on or more directions, e.g., to avoid or minimize deflection of the channel52into a position that may obscure the field of view beyond the apparatus10. In still another alternative, the channel52may be transparent or semi-transparent to light in the spectra used for imaging, e.g., to facilitate visualization of devices, instruments, agents, and/or fluids passing through the tubular member. Alternatively, the channel52may be replaced or reinforced with any suitable stiffening element such as a wire, spring, composite element, plastic element, and the like.

As best seen inFIG. 1B, the interior60of the balloon50may have a generally annular shape that preferably communicates with the inflation lumen20b(not shown, seeFIG. 1C) of the catheter12. Substantially transparent inflation media, e.g., saline, carbon dioxide, nitrogen, air, and the like, may be introduced into the interior60of the balloon50to expand the balloon50towards the enlarged condition shown inFIGS. 1A and 1B. As used herein, “transparent” refers to any material and/or fluid that may permit sufficient light to pass therethrough in order to identify or otherwise visualize objects through the material and/or fluid. “Light” as used herein may refer to light radiation within the visible spectrum, but may also include other spectra, such as infrared (“IR”) or ultraviolet (“UV”) light.

Alternatively, the balloon and/or channel may have different configurations, such as that shown inFIGS. 3A-3Cand4. For example, as shown inFIGS. 3A-3C, an apparatus110is shown that includes a catheter112that may include one or more lumens, e.g., lumens120c,120dfor receiving components of an imaging assembly162therethrough, similar to the previous embodiment. Unlike the previous embodiment, a cannulation lumen120aextends along an outer surface of the catheter112that extends between a proximal end (not shown) to a distal end116of the catheter112. The lumen120amay be a separate tubular member attached to the catheter112or may be an integral part of the catheter112, e.g., formed as a single extrusion.

A balloon150may be carried on the distal end116of the catheter112that defines an interior160communicating with an inflation lumen (not shown) that extends to the proximal end of the catheter112, similar to the previous embodiment. A channel152may extend along a wall of the balloon150that communicates with the cannulation lumen120a. The channel152may be defined by a panel of material attached to the balloon150, similar to the materials and methods for making balloon50, as described above. Alternatively, an inner balloon panel may be provided within an outer balloon panel and the panels may be attached to one another, e.g., along one or more seams defining the channel152.

A nipple or annular collar157may be provided on the distal surface154of the balloon150, e.g., to guide a guidewire80or other instrument out of the balloon150, and/or to stabilize the device relative to a body lumen or other tissue structure (not shown). Thus, a guidewire80may be inserted into the cannulation lumen120afrom the proximal end of the catheter112, the channel152guiding the guidewire80through the balloon150until it exits through the nipple157to a location beyond the distal surface152of the balloon150.

In another alternative, shown inFIG. 4, an inner balloon251may be provided within an interior260of an outer balloon250. The inner balloon251may be expandable to a size and/or shape that is smaller than the outer balloon250, thereby defining a channel252between the balloons251,252. Thus, a guidewire80or other instrument (not shown) may be inserted into a cannulation lumen220a, e.g., extending along an outer surface of the catheter212. The guidewire80may enter the channel252between the balloons251,252until it exits through a nipple257, similar to the embodiment shown inFIGS. 3A-3C.

In yet another alternative, shown inFIGS. 5A-5C, an apparatus310may be provided that includes a mechanically expandable member350carried on a distal end316of a catheter312. A frame352may be coupled to the distal end316that may support a substantially transparent, flexible membrane354. The frame352may include a plurality of members that are movable away from and towards one another, thereby causing the membrane354to move between contracted and enlarged conditions. Alternatively, the frame352may be constructed of plastic or wire mesh, or of a laser cut expandable framework.

The frame352may be actuated from a proximal end (not shown) of the catheter312, e.g., to cause the frame352to expand radially outwardly, as shown inFIGS. 5B and 5C. As the frame352expands, the membrane354may provide a substantially transparent surface356through which an optical imaging assembly, e.g., including an optical fiber bundle364and/or a light guide368, similar to that described further below, may obtain optical images. Optionally, an interior358of the membrane354may be filled with a substantially transparent fluid, similar to the balloons described above, to facilitate imaging through the expandable member350.

Returning toFIGS. 1A-1C, the imaging assembly62generally includes an optical imaging element64that is exposed within the interior60of the balloon50for capturing light images through the balloon50. In one embodiment, the optical imaging element comprises an image sensor such as a CCD, CMOS, and the like disposed distally, e.g., adjacent or within the distal end16. In another embodiment, the optical imaging element64may include a bundle of optical fibers, e.g. a coherent image bundle, that extends between the proximal and distal ends14,16of the catheter12, e.g., through the lumen20d, as shown inFIG. 1C. The fiber bundle64may include about ten thousand (10,000) optical fibers, although it may include between about one and fifty thousand (1,000-50,000) fibers in order to provide a desired resolution in the images obtained by the fiber bundle64.

A lens66, e.g., a GRIN or self-oc lens, may be coupled to the fiber bundle64in order to focus light from beyond the distal surface54of the balloon50onto the fiber bundle64in order to generate a resolved image at the proximal end of the fiber bundle64, as is well known to those skilled in the art. Optionally, a directional prism or other optical element (not shown) may be provided for directing a field of view of the fiber bundle64as desired, as explained further below. In order to decrease the tendency of bubbles to adhere to the distal surface of a distal lens or other optical element (not shown), the lens may be coated with a hydrophilic coating, or designed such that its geometry or the surrounding catheter geometry decreases the tendency of bubbles to adhere, e.g., by providing a convex exposed surface. Other features, such as directed flushing, may be employed to dislodge any adhered bubbles during use.

In addition, the imaging assembly62may include one or more light sources disposed at the distal end16of the catheter12. For example, the light sources may be one or more light emitting diodes. Alternatively, the imaging assembly62may include one or more light guides68carried by the distal end16of the catheter12for delivering light into the interior60and/or through the distal surface54of the balloon50. Although a single light guide68is shown inFIGS. 1B and 1C, it will be appreciated that a plurality of light guides (not shown) may be provided in a common lumen or separate lumens (also not shown) within the catheter12. The light guide(s)68may include a plurality of optical fibers, e.g., formed from acrylic and the like, that may extend to the proximal end14of the catheter12. As shown inFIG. 1A, a source of light70may be coupled to the light guide(s)68, e.g., via the handle30, for delivering light through the light guide(s)68and into the balloon50.

A device72may be coupled or otherwise provided at the proximal end14of the apparatus10for acquiring and/or capturing images obtained by the optical imaging assembly62. For example, one or more lenses (not shown) may be coupled to the fiber bundle64for focusing and/or resolving light passing through the fiber bundle64, e.g., to pass the image to the device72. The device72may include a CCD, CMOS, and/or other device, known to those skilled in the art, e.g., to digitize or otherwise convent the light images from the fiber bundle64into electrical signals that may be transferred to a processor and/or display (not shown).

For example, a computer (not shown) may be coupled to the device72(, seeFIG. 1A), e.g., by a cable (not shown). Alternatively, instead of the computer, other display or capture devices may be coupled to the device72, such as a laptop computer, handheld or PDA device, a computer terminal, a LCD display, standard video monitor, and the like (not shown), to display and/or store the images acquired from the fiber bundle64. Optionally, the computer (or other capture device) may provide electrical power to the device72, light source70, and/or other components of the apparatus10.

For a cable connection between the device72and the computer, various protocols may be used, such as USB, Firewire, standard video signal protocols, and the like. Alternatively, the computer may be coupled to the device72via a wireless connection, for example, including one or more transmitters and/or receiving using radio frequency signals, Bluetooth, infrared links, and the like.

Optionally, the apparatus10may include additional data acquisition features, such as a microphone (not shown), e.g., allowing procedure notes to be dictated during an imaging procedure or allowing the apparatus10and/or computer10to be controlled by voice commands. In addition or alternatively, drivers and/or software may be stored on a memory chip (not shown) in the apparatus10that may be uploaded to the computer when connected to the apparatus10. When a complex interface is used to connect the apparatus10to the computer or other display device, the apparatus10and/or the computer may be capable of disabling the complex interface and enable simple video output.

Turning toFIGS. 6-10, another preferred embodiment of an apparatus410is shown for visualizing and/or cannulating a body lumen. Similar to the previous embodiments, the apparatus410generally includes a catheter412, a balloon450carried by the catheter412, and an imaging assembly462for imaging through the balloon450.

Also, similar to the previous embodiments, the catheter412may be an elongate tubular body including a proximal end414, a distal end416, and a central longitudinal axis418extending therebetween. The catheter412may be substantially flexible, semi-rigid, and/or rigid along its length, and may be formed from a variety of materials, including plastic, metal, and/or composite materials. The catheter412may have a diameter between about five and ten French (1.67-3.33 mm), and preferably between about six and eight French (2.00-2.67 mm).

The catheter412may include one or more lumens420also extending between the proximal and distal ends414,416, e.g., a cannulation lumen420a, an inflation lumen420b, and one or more lumens420c-ffor the imaging assembly462and/or one or more pullwires or other steering elements422. In addition, the catheter412may include a handle (not shown) and/or other components, e.g., sources of fluid, a light source, an image capture device, and the like (also not shown) on the proximal end414, similar to the other embodiments described herein.

Preferably, the catheter412includes multiple extrusions that are attached to one another to provide a desired length. For example, the catheter412may include a proximal portion412ahaving a first cross-section, shown inFIGS. 8A and 8B, and a distal portion412bhaving a second cross-section, shown inFIG. 8C. The proximal portion412amay have a length between about nine and thirty six inches (22-90 cm), and preferably between about eighteen and twenty eight inches (45-70 cm).

The proximal portion412apreferably includes three lumens, a cannulation lumen420a, an inflation lumen420b, and an accessories lumen420c. The cannulation lumen420amay provide a path for a guidewire or other instrument, fluid, and the like to pass between the proximal and distal ends414,416of the catheter412. Optionally, a tube424, e.g., made from polyamide and the like, may be provided within the cannulation lumen420a, e.g., to reinforce the cannulation lumen420aand/or catheter412. The inflation lumen420bmay communicate with an interior460of the balloon450, similar to the previous embodiments, for delivering substantially transparent inflation media into the balloon450. The accessories lumen420cmay carry a plurality of components, e.g., an optical imaging (fiber optic) bundle464, pull-wire422, and/or a set of light guides468, similar to the previous embodiments described above.

With reference toFIGS. 7A and 8C, the distal portion412bmay have a length between about 25.4-101.6 millimeters (mm), and preferably between about 50.8-76.2 millimeters (mm). The distal portion412bmay be substantially permanently attached to the proximal portion412a, e.g., using a lap or butt joint, and/or an adhesive, interference fit, heating, and/or sonic welding. The distal portion412bmay include continuations of the cannulation lumen420aand inflation lumen420bfrom the proximal portion412a. In addition, the distal portion412bmay include a light guide lumen420d, a fiber optic lumen420e, and a pullwire lumen420fthat may communicate with the accessories lumen420cwhen the proximal and distal portions412a,412bare attached to one another.

Preferably, the fiber optic lumen420eis located as far away from the cannulation lumen420aas possible in order to maximize a field of view of the fiber bundle464received therein. For example, as shown inFIG. 8C, the distal portion412bmay include a ridge421extending axially along an outer surface of the distal portion412b, thereby maximizing a distance that the fiber optic lumen420emay be disposed away from the cannulation lumen420a. When the fiber bundle464is inserted into the catheter412, the fiber bundle464may be received in the fiber optic lumen420ein the distal portion412b, and in the accessories lumen420cin the proximal portion412a. The fiber bundle464may be secured at one or more locations within the lumens420e,420c, e.g., using an adhesive and the like. Thus, the location of the fiber bundle464may be fixed in the distal portion412bto stabilize its field of view relative to the catheter412.

The pullwire lumen420fmay also be located as far away from the central axis418, e.g., due to another ridge extending the outer surface. This arrangement may maximize a bending force applied to the catheter412when the pullwire422is pulled proximally.

Turning to FIGS.7B and9A-9C, the set of light guides468may be received in the accessories lumen420cin the proximal portion412aand in the light guide lumen420din the distal portion412b. The set of light guides468may include between about one and twenty five, and preferably between about four and ten, elongate light guides. Each of the light guides468may be formed from a substantially transparent acrylic fiber or other light transmitting material, e.g., having a diameter between about twenty five micrometers and one millimeter (25 μm-1 mm), and preferable between about two hundred fifty and five hundred micrometers (250-500 μm).

At the proximal end414of the catheter412, the light guides468may be substantially cylindrical, while towards the distal end416of the catheter412, the light guides468may be tapered and/or flattened. For example, the light guides468may taper within a few inches of the proximal end414of the catheter412, preferably reducing an overall cross-section of the light guides468by as much as fifty percent (50%). The light guides468may be disposed loosely within the accessories lumen420cof the proximal portion412a.

The enlarged size of the light guides468at the proximal end414of the catheter412may facilitate connecting the light guides468to a light source (not shown), as will be appreciated by those skilled in the art. Optionally, exposed lengths (not shown) of the light guides468beyond the proximal end414of the catheter412may be further enlarged to facilitate such connections. For example, if the light guides468are acrylic fibers, heat may be applied, e.g., up to one hundred seventy degrees Fahrenheit (170° F.), to cause the light guides468to shorten. The acrylic material may increase in diameter as it shortens, thereby increasing the diameter of the light guides468by as much as three times as they shorten. This may allow the light guides468to be columnated and connected to a light source without requiring a lens (not shown).

As the light guides468transition from the proximal portion412ato the distal portion412b, they may be linearly aligned and/or secured to each other, e.g., using an epoxy or other adhesive, and/or by reflowing the fiber material, such that surfaces of adjacent fibers are bonded at adjacent contact points. To align the light guides468in a desired orientation within the distal portion412b, the light guides468may be received in an axial ridge or slot423within the distal portion412b, as shown inFIG. 8C.

The bonded array of light guides468may provide a hinge, i.e., biasing the distal portion412bof the catheter412to bend in a predetermined direction. Specifically, the light guides468may provide a higher bending moment along a bond axis “x” (shown inFIG. 9C), while exhibiting a much lower bending moment along an axis orthogonal to the bond axis “x.” As the pullwire422is pulled proximally, the force may be transferred to the distal portion412bof the catheter412. Because of the asymmetric bending moments created by the light guides468, the distal portion412bof the catheter412may bend in one plane orthogonal to the bond axis “x,” i.e., towards the pullwire422, while resisting bending along the bond axis “x.” This may cause the catheter412to curve from a location where the pullwire422transitions from being located at the center of the catheter412(e.g., as shown inFIG. 8A) to a location on the distal end416where the pull wire422is fixed (e.g., as shown inFIG. 8C).

Turning toFIGS. 10-11B, a bundle464of optical fibers may be provided, similar to the embodiments described above. Preferably, a lens466is coupled to the fiber bundle464, e.g., a GRIN or self-oc lens, as described above. For example, as shown inFIGS. 11A and 11B, a sleeve467, e.g., shrink wrap and the like, may be provided that may be secured around the lens466and the optical imaging bundle464. Optionally, a fluid or other material (not shown) may be provided between the lens466and the optical imaging bundle464to minimize losses and/or reflection at the transition, as is known to those skilled in the art.

Turning toFIG. 10with continued reference toFIG. 6, a tubular extension430may extend from the distal end416of the catheter412. The tubular extension430may include a lumen432extending between proximal and distal ends434,436of the tubular extension430. Preferably, the tubular extension430has a substantially smaller diameter or other cross-section than the distal end416of the catheter412.

The proximal end434of the tubular extension430may be attached to the distal end416of the catheter412such that it is coextensive with the cannulation lumen420a. Thus, an instrument or fluid introduced through the cannulation lumen420amay pass freely through the lumen432of the tubular extension430. In addition, attaching the tubular extension430eccentrically to the catheter412opposite the optical imaging bundle464may minimize the extent that the tubular extension430obstructs the field of view of the optical imaging bundle464.

In one embodiment, the proximal end434of the tubular extension430may be at least partially received in the cannulation lumen420aor in a recess (not shown) concentric with the cannulation lumen420a. Alternatively, the proximal end434of the tubular extension430may be butted against the distal end416of the catheter412. In addition or alternatively, the tubular extension4430may be bonded to the catheter412, e.g., using an adhesive, heating, sonic welding, and the like.

The balloon450may include a proximal end452attached to the distal end416of the catheter412and a distal end456attached to the distal end of the tubular extension430. The proximal end452of the balloon450may be secured to the outer surface of the catheter412, e.g., using an adhesive, heating, an interference fit, an outer collar (not shown), and the like, similar to the other embodiments described herein.

Turning toFIGS. 12A-12D, an imaging apparatus10, such as any of those described elsewhere herein, may be included in a system or kit, along with an elongate rail80, and/or a lead100. As shown, the elongate rail80is a guidewire including a proximal end (not shown), a distal end83, and one or more fixation elements82on the distal end83. In the exemplary embodiment shown, the fixation element82is a helical screw, which may include a sharpened tip to facilitate penetration into tissue. As the guidewire80is rotated about its longitudinal axis, the helical screw82may be screwed into tissue. To remove the helical screw82, the guidewire80may be rotated in the opposite direction.

In alternative embodiment, the fixation element82may include other structures, e.g., that actively secure the distal end83, e.g., adhesives, hooks, pinchers, barbs, and the like. If the guidewire80is secured within a body lumen, e.g., a pulmonary artery, coronary vein, and the like, the fixation element82may be an expandable device, e.g., a balloon or mechanically expandable device that may frictionally or otherwise engage surrounding tissue to secure the distal end83.

During use, the imaging apparatus10and rail80may be used to deliver a pacing or other transvenous lead into a patient's body, e.g., endoluminally to a target location within a body lumen or cavity, or surgically into body cavities, such as the thoracic cavity for epicardial lead placement.FIGS. 12A-12Dshow an exemplary endocardial placement. Initially, as shown inFIG. 12A, the imaging apparatus10may be advanced through the patient's vasculature, from a percutaneous entry site, e.g., at a subclavian or femoral vein, into the patient's heart. As shown, the distal end16of the imaging catheter12may be introduced through the right atrium92and into the right ventricle98.

An imaging device, e.g., including expandable member50and one or more lenses or other imaging assemblies may be used to visualize the interior of the right ventricle98to facilitate identifying a suitable delivery location96. For example, with the expandable member50expanded, the distal end16may be directed against a wall of the right ventricle98, e.g., against the right ventricular septum, and manipulated to move the expandable member50(and imaging assembly) along the wall to identify a target delivery location96.

Turning toFIG. 12B, once a target location96is identified, the elongate rail80is introduced via the imaging apparatus10to the target delivery location. As shown, the rail80is a guidewire that may be through an instrument lumen (not shown) in the imaging apparatus10, e.g., from the proximal end (not shown) to the distal end16until the guidewire80is disposed adjacent or beyond the expandable member50at the delivery location96. The fixation element82on a distal end83of the guidewire80may be used to secure the guidewire80to the right ventricle98at the target location96.

In an alternative embodiment, the rail may include a sheath or other tubular member (not shown) that may be advanced through a lumen of the imaging apparatus10or may be advanced around the imaging apparatus10. The tubular member may include one or more fixation elements on the distal end, which may be used to secure the tubular member to the target location96.

Turning toFIG. 12C, the imaging apparatus10may then be removed, leaving the rail80secured within the right ventricle98. For example, the expandable member50may be collapsed, and the imaging apparatus10removed over (or through) the rail80.

As shown inFIG. 12D, an electrical pacing lead100and/or other instrument may then be advanced through the heart via the rail80until the lead100is disposed within the right ventricle98at the delivery location96. Because cardiac leads are extremely flexible or floppy, the relative strength and/or rigidity of the guidewire80may facilitate advancing the lead100through larger vessels, where the lead100may otherwise wander or bind up. The lead100may then be affixed to the delivery location96, by attaching the fixation element to the delivery location. As shown, the lead100include a lumen for receiving the rail80therethrough, thereby allowing the lead to be advanced over the rail80. Alternatively, the lead100may be introduced through a lumen of the rail, e.g., if the rail is a sheath or other tubular member (not shown).

The lead100may include a helical screw (not shown) or other fixation element, similar to the rail80for securing the lead100relative to the target location96. In this embodiment, the rail80may be removed, either before or after securing the lead100to the target location96. Alternatively, the rail80may remain secured at the target location96. In this alternative, the lead100may include one or more connectors that may secure the lead100to the rail80, thereby securing the lead relative to the target location96.

In the another embodiment shown inFIG. 13A-13D, an imaging apparatus10, such as those described elsewhere herein, may be advanced into a body cavity, e.g., into a thoracic cavity. For example, the heart may be exposed using a sternotomy or a minimally invasive approach, e.g., involving one or more ports (not shown) may be used to access the thoracic cavity and/or pericardial sac of the heart.

As shown inFIG. 13A, a distal end16of the imaging catheter12may be disposed adjacent the patient's heart. The imaging apparatus10is maneuvered through the pericardial space (not shown) until the expandable member50is placed against the epicardium of the heart. The expandable member50may be expanded, and the epicardium imaged to identify a target delivery location96, e.g., above the right ventricle98. An imaging assembly (not shown) in the expandable member50may be used to directly visualize the exterior of the right ventricle98, which may facilitate identifying a suitable delivery location96.

Turning toFIG. 13B, an elongate rail80may be advanced through a lumen (not shown) in the imaging apparatus10, e.g., from a proximal end (not shown) to the distal end16, until the rail80is disposed beyond the expandable member50at the delivery location96. A fixation element82on a distal end83of the guidewire80may be used to secure the guidewire80to the epicardium of the heart at the target location96. As shown, the fixation element82is a helical screw, similar to the previous embodiment.

Turning toFIG. 13C, the imaging apparatus10may then be removed, leaving the rail80secured to the target location96. As seen inFIG. 13D, an electrical pacing lead100and/or other instrument may then be advanced through the pericardial space along the rail80until the lead100is disposed adjacent the delivery location96. Because cardiac leads are extremely flexible or floppy, the relative strength and/or rigidity of the rail80may facilitate advancing the lead through the pericardial space, where the lead100may otherwise wander or bind up. The lead100may then be affixed to the delivery location96, by attaching a fixation element (not shown) on the lead100to the delivery location96. The guidewire80may then be removed. Alternatively, the guidewire80may remain secured at the delivery location96.

Alternatively and/or in addition, the apparatus previously described herein may also incorporate deflectability, steerability, and/or a pre-shaped element or a combination of these features in order to achieve further improved navigability.

Although different embodiments have been described herein with particularity as including specific components and/or features, it will be appreciated that each of the embodiments described above may include components and/or features specifically described with respect to individual embodiments. For example, any of the embodiments described above may include one or more of the following: a handle on a proximal end of a catheter, one or more pullwires or other steering elements for steering a catheter and/or a localization/stabilization member, steering controls or actuator, a source of light, a capture device, e.g., including a display, processor for analyzing image data, and/or memory for storing imaging data, sources of fluid, e.g., for delivering inflation media, diagnostic, and/or therapeutic agents, and the like. Thus, different components may be provided on each of the embodiments, depending upon a specific application.

In addition, each of the apparatus described may be used to perform any of the procedures described herein and should not limited to the specific examples described. For example, any of the apparatus described may be used for imaging, accessing, and/or cannulating a collapsible lumen, such as the colon. Embodiments with channels through balloons or other expandable and/or displacement members may be used to deliver insufflation media, e.g., carbon dioxide, nitrogen, and/or air, into a collapsible lumen to facilitate performing a procedure therein.