Abstract:
An apparatus and method are provided for preparing a vein. A first tubular member end, defining a first lumen, is inserted into a cannulated vein, over a first guide wire. A second tubular member end, defining a second lumen, has a cutting member operably engaged therewith, and is inserted into the vein so as to intersect with and extend into the first tubular member, remotely to the first tubular member end, to establish communication between the first and second lumens, and such that a second guide wire received through the second lumen extends into the first lumen. Withdrawal of the first tubular member from the vein, over the first guide wire, causes the cutting member to longitudinally divide the first tubular member, from the intersection between the tubular members to the first tubular member end, to allow the second guide wire to pass through the division.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    Embodiments of the present invention are generally directed to surgical devices and, more particularly, to an apparatus and method for facilitating implantation of leads of a cardiac pacemaker. 
         [0003]    2. Description of Related Art 
         [0004]    A heart is essentially a muscle that can beat over one million times during its service life (i.e., the lifetime of the entity). Normally, the heart beats in a “regular” manner, but the beats increase or decrease in response to the needs or condition of the entity&#39;s body. The heart generally beats in response to electrical signals that are provided by the entity&#39;s body and are propagated to the heart in a coordinated manner. Each electrical signal or impulse thus causes the heart (muscle) to contract in a corresponding coordinated manner to provide the pumping function for the blood in the entity&#39;s body. 
         [0005]    As the entity ages, the complex beat regulation mechanism for the heart may become damaged or may otherwise malfunction. In such instances, the heart may fail to beat adequately or appropriately to meet the needs of the entity&#39;s body, thereby causing fainting spells or other problems, and may eventually result in sudden death. In some instances, in order for the heart to continue to beat in an appropriate manner of the body, the required electrical signals or impulses must be restored to the muscle comprising the heart. In one instance, the required electrical signals or impulses may be provided by a (cardiac) pacemaker, which generally comprises a device implanted into the body of the entity for providing the necessary electrical signal/impulse generation for the heart. 
         [0006]    The implantation of such a pacemaker device into the body may, in some instances, be considered a “minor” surgical technique or procedure. For example, during a typical implant procedure, as shown in  FIG. 1 , the pacemaker device  1  is placed just under the chest tissues through a small incision. In some instances, two insulated wires or leads  2 ,  3  attached to the pacemaker device are used to deliver the required electrical signals/impulses, via an electrical current, to the upper right chamber (atria/atrium  4 ) and to the lower right chamber (ventricle  5 ) of the heart  6 . 
         [0007]    In order for the pacemaker wires/leads to be appropriately placed in the atria  4  and ventricle  5  of the heart  6 , a vein leading to the heart  6  must first be accessed (i.e., entrance into the vein) by the surgeon. In some instances, the procedure may be facilitated by the accessed vein being relatively large. For example, the selected vein may be the subclavian vein  10 , as shown in  FIG. 2 . To access this vein, a large hollow needle, defining a needle lumen extending therethrough, may be first inserted through the skin and into the vein (i.e., to cannulate the vein). An appropriate wire is then inserted through the needle lumen and into the vein. The needle is then withdrawn over the wire, leaving the wire in and extending along the vein. The wire thus acts as a “guide” for the insertion of other devices from outside the body into the vein. In one pacemaker insertion procedure, a relatively large cylinder or sheath is then inserted into the vein, over the wire, and the wire then removed. Upon removal of the wire, the sheath remaining in the vein provides a portal into the vein from outside the body. Any suitable, appropriately sized (i.e., small) device such as, for example, the pacemaker wire(s)/lead(s) can then be inserted into the vein from outside the body. 
         [0008]    In some instances, each pacemaker wire/lead may be insulated with a relatively durable material. Nevertheless, due to the relative scale of the wire(s)/lead(s), the insulation may sometimes be readily damaged, for example, by being torn by a needle. The damaged insulation thus renders the wire/lead useless for the purposes of a pacemaker device. Accordingly, the relatively fragile nature of the pacemaker wire/lead may be one reason for the wire being initially used as a guide to the vein in the needle insertion procedure, instead of the pacemaker wire/lead itself. 
         [0009]    The needle insertion step may be the most risky portion of the pacemaker implantation procedure. For example, in some instances, the needle may miss the vein entirely. In other instances, for example, the needle may be inadvertently inserted too far, piercing completely through the vein, extending to and puncture the lung, or otherwise causing an emergency situation. Since two pacemaker wires or leads are typically utilized by a pacemaker device (one wire/lead extending to the upper chamber or atrium  4 , and one wire/lead extending to the lower chamber or ventricle  5 ), two separate hollow needle insertions are generally used during the pacemaker implantation procedure. However, doubling the number of needle insertions may also correspondingly double the risk of complications. 
         [0010]    Thus, there exists a need for an apparatus and method for facilitating implantation of leads of a cardiac pacemaker that eliminates or minimizes the risk of complications for the entity/patient during a pacemaker implantation procedure and/or the risk of damage to the leads of the pacemaker device during the implantation process. 
       BRIEF SUMMARY OF THE INVENTION 
       [0011]    The above and other needs are met by aspects of the present invention which, in one embodiment, provides an apparatus for preparing a vein leading to a heart for insertion of leads of a cardiac pacemaker therein. Such an apparatus comprises a first tubular member defining a first lumen and having an end. The end of the first tubular member is adapted to be inserted into a cannulated vein, over a first guide wire inserted into the vein, so as to extend along the vein over the first guide wire. A second tubular member defines a second lumen and has an end with a cutting member operably engaged therewith. The end of the second tubular member is configured to be inserted into the vein proximate to the first tubular member. The second tubular member is configured to cooperate with the first tubular member such that the end of the second tubular member intersects with and extends into the first tubular member, remotely with respect to the end of the first tubular member, to establish communication between the first and second lumens such that a second guide wire received through the second lumen extends from the second lumen into the first lumen along the first guide wire. The second tubular member is further configured such that withdrawal of the first tubular member from the vein, over the first guide wire, causes the first tubular member to be longitudinally divided by the cutting member, from the intersection between the first and second tubular members to the end of the first tubular member, so as to allow the second guide wire to pass through the longitudinal division. 
         [0012]    Another aspect of the present invention provides a method of preparing a vein leading to a heart for insertion of leads of a cardiac pacemaker therein. Such a method comprises cannulating the vein and inserting a first guide wire therein such that the first guide wire extends along the vein. An end of a first tubular member, defining a first lumen, is then inserted into the cannulated vein over the first guide wire, wherein the first lumen is configured to receive and extend along the first guide wire. An end of a second tubular member, defining a second lumen and including a cutting member operably engaged with the end thereof, is then inserted into the vein proximate to the first tubular member, such that the end of the second tubular member intersects with and extends into the first tubular member, remotely with respect to the end of the first tubular member, to establish communication between the first and second lumens. A second guide wire is inserted through the second lumen such that the second guide wire extends from the second lumen into the first lumen along the first guide wire. The first tubular member is then withdrawn from the vein, over the first guide wire, such that the first tubular member is longitudinally divided by the cutting member, from the intersection between the first and second tubular members to the end of the first tubular member, so as to allow the second guide wire to pass through the longitudinal division. The second tubular member is withdrawn from the vein, over the second guide wire, such that the first and second guide wires remain within and extend along the vein. First and second sheaths, defining respective first and second sheath lumens, are then inserted into the vein over the respective first and second guide wires, wherein the first and second sheath lumens are configured to respectively receive and extend along the first and second guide wires disposed within and extending along the vein. The first and second guide wires are then withdrawn from the vein through the respective first and second sheath lumens, and first and second leads of the cardiac pacemaker are then inserted through the respective first and second sheath lumens, such that the first and second leads extend to the heart 
         [0013]    Embodiments of the present invention thus provide an apparatus and method that can be used after the first needle insertion in the vein leading to the heart during a cardiac pacemaker implantation procedure using, for example, the Seldinger technique, wherein such an apparatus and method facilitates the procedurally-required second needle insertion into the vein, while reducing or minimizing the risk of, for instance, the second needle insertion missing the vein or undesirably extending completely through the vein, and thereby avoiding or minimizing the risk of inadvertent trauma to surrounding tissues or the lung of the patient during the cardiac pacemaker implantation procedure. As such, aspects of the present invention provide distinct advantages as otherwise disclosed herein. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
         [0014]    Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein: 
           [0015]      FIG. 1  schematically illustrates a cardiac pacemaker implanted into a patient; 
           [0016]      FIG. 2  schematically illustrates a vein leading to the heart, cannulated with a first guide wire using, for example, the Seldinger technique; 
           [0017]      FIG. 3A  schematically illustrates a first tubular member of a vein preparation apparatus for insertion of pacemaker leads, according to one aspect of the present invention, extending over the first guide wire for insertion into the vein; 
           [0018]      FIG. 3B  schematically illustrates an engagement mechanism operably engaged between the first and second tubular members of a vein preparation apparatus for insertion of pacemaker leads, according to one aspect of the present invention; 
           [0019]      FIG. 4  schematically illustrates a first tubular member of a vein preparation apparatus for insertion of pacemaker leads, according to one aspect of the present invention, extending over the first guide wire and inserted into the vein, with a second tubular member, according to one aspect of the present invention, also inserted into the vein in cooperation with the first tubular member via the engagement mechanism operably engaged therebetween; 
           [0020]      FIG. 5  schematically illustrates a vein preparation apparatus for insertion of pacemaker leads, according to one aspect of the present invention, with the second tubular member inserted into the vein and extending into the first tubular member so as to establish communication between first and second lumens defined by the respective first and second tubular members; 
           [0021]      FIGS. 6A-6C  schematically illustrate an insertion sequence of the second tubular member of a vein preparation apparatus for insertion of pacemaker leads, according to one aspect of the present invention, being inserted into the vein and extending into the first tubular member so as to establish communication between first and second lumens defined by the respective first and second tubular members; 
           [0022]      FIG. 6D  schematically illustrates a second guide wire inserted into the vein through the established communication between the first and second tubular members of a vein preparation apparatus for insertion of pacemaker leads, according to one aspect of the present invention; 
           [0023]      FIG. 7  schematically illustrates a releasable locking mechanism associated with the engagement mechanism operably engaged between the first and second tubular members, according to one embodiment of the present invention, for determining relative movement between the first and second tubular members; 
           [0024]      FIG. 8  schematically illustrates the insertion of a second guide wire through the second tubular member and into the first tubular member, so as to extend along the vein with the first guide wire, due to the communication between the first and second lumens upon the second tubular member being inserted into the first tubular member, according to one embodiment of the present invention; 
           [0025]      FIG. 9  schematically illustrates one embodiment of a first tubular member of a vein preparation apparatus for insertion of pacemaker leads, according to one aspect of the present invention, wherein the first tubular member includes a receptor site and a withdrawal path; 
           [0026]      FIG. 10  schematically illustrate a cutting member associated with the end of the second tubular member, and configured to longitudinally divide the first tubular member from the intersection between the first and second tubular members to the end of the first tubular member, upon withdrawal of the first tubular member from the vein, according to one embodiment of the present invention; 
           [0027]      FIG. 11  schematically illustrate the withdrawal of the first tubular member from the vein, separately from the second tubular member, upon the release of the locking mechanism, so as to allow relative movement between the first and second tubular members, according to one embodiment of the present invention; 
           [0028]      FIG. 12  schematically illustrates the longitudinal division of the first tubular member by the cutting mechanism associated with the second tubular member upon withdrawal of the first tubular member from the vein, according to one embodiment of the present invention; 
           [0029]      FIG. 13  schematically illustrates the first and second guide wires remaining within the vein, the second guide wire being disposed within the second tubular member, after withdrawal of the first tubular member from the vein, according to one embodiment of the present invention; 
           [0030]      FIG. 14  schematically illustrates the first and second guide wires remaining within the vein, after withdrawal of the first and second tubular members, according to one embodiment of the present invention, wherein the first and second guide wires disposed within the vein being configured and prepared to receive appropriate and respective first and second sheaths thereover for facilitating insertion of the pacemaker leads therethrough into the heart; and 
           [0031]      FIGS. 15-18  schematically illustrate the pacemaker implantation process, whereby respective sheaths are inserted into the vein over the first and second guide wires, the first and second guide wires then withdrawn, the leads of the pacemaker device then inserted through the sheaths into the vein, and the sheaths then withdrawn and the pacemaker device attached to the leads extending into the vein and to the heart. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0032]    The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the inventions are shown. Indeed, these inventions may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout. 
         [0033]      FIG. 2  schematically illustrates a vein leading to the heart  6 , such as the subclavian vein  10 . Using, for example, the Seldinger technique, as will be appreciated by one skilled in the art, the subclavian vein  10  may be cannulated with a hollow needle so as to insert a first guide wire  20  therein. Upon removal or withdrawal of the hollow needle, the first guide wire  10  remains within the subclavian vein  10 . 
         [0034]      FIG. 3A  schematically illustrates a vein preparation apparatus  100  according to one embodiment of the present invention. Such a vein preparation apparatus  100  may be particularly configured, for example, for facilitating insertion of operative wires or leads  2 ,  3  of a pacemaker device  1 , according to one aspect of the present invention. The vein preparation apparatus  100  comprises, for instance, first and second tubular members  40 ,  50 . One skilled in the art will appreciate that each of the first and second tubular members  40 ,  50  defines a respective lumen  40 A,  50 A extending along the length thereof. Each of the first and second tubular members  40 ,  50  includes respective first and second insertion ends  30 ,  90  for insertion into the vein  10 , as further discussed herein. Opposite the first and second insertion ends  30 ,  90 , the respective first and second tubular members  40 ,  50  each include a valve mechanism  60 ,  70 . Each valve mechanism  60 ,  70  is configured to allow a guide wire, such as the first guide wire  20 , to pass therethrough, but preferably and substantially prevents the flow of blood or other fluids therethrough. For example, each valve mechanism  60 ,  70  may comprise a self-sealing diaphragm or any other suitable “one-way” valve. As shown, the first tubular member  40  of the vein preparation apparatus  100  is first inserted over the first guide wire  20  through the insertion end  30  thereof, such that the first guide wire  20  extends from the vein  10  through the first lumen  40 A defined by the first tubular member  40 . 
         [0035]      FIG. 3B  schematically illustrates that each of the first and second tubular members  40 ,  50  may include complementary and interacting first and second portions  110 ,  120  of an engagement mechanism  130  operably engaged between the first and second tubular members  40 ,  50  of the vein preparation apparatus  100 . In one aspect, the first and second portions  110 ,  120  of the engagement mechanism  130  are particularly configured to effect a sliding relation between the first and second tubular members  40 ,  50 . That is, the engagement between the first and second portions  110 ,  120  may allow only relative longitudinal movement and/or substantially parallel movement between the first and second tubular members  40 ,  50 . For example, the first portion  110  engaged with the first tubular member  40  may be configured as a “T” shaped member, while the second portion  120  engaged with the second tubular member  50  may be configured as a “C” shaped channel appropriate for receiving the “T” shaped member therein. The engagement mechanism  130 , thus configured, allows the first and second tubular members  40 ,  50  to “slide” relative to each other, which may be useful, for example, when one tubular member is inserted into or withdrawn from the vein  10  separately from the other tubular member, as discussed further herein. In some instances, a friction-reducing substance (i.e., Teflon™, polytetrafluouroethylene, or any other suitable friction-reducing substance) may be applied to either or both of the first and second portions  110 ,  120 , so as to facilitate the sliding relation therebetween. 
         [0036]    According to one aspect of the present invention, the first tubular member  40  may be configured to be flexible and formed of a suitable and appropriate material for insertion into a patient&#39;s body, as will be appreciated by one skilled in the art. For example, the first tubular member  40  may be comprised of a metallic material, a polymeric material, a composite material, or any other suitable and appropriate material or combinations thereof. Further, the end  30  of the first tubular member  40  is particularly configured to be capable of insertion into the vein  10  through the opening therein formed by the hollow needle originally used to cannulate the vein  10 . That is, one skilled in the art will appreciate that the end  30  may not necessarily be “sharp” since the first tubular member  40  is being inserted into the vein  10  through an existing hole. However, the end  30  may also be “sharp” (i.e., capable of independently piercing the vein  10 ) where necessary of desirable. 
         [0037]    Once the first tubular member  40  is installed over the first guide wire  20  and the end  30  thereof inserted into the vein  10 , as shown in  FIG. 4 , the first tubular member  40  may be at least partially advanced over the first guide wire  20  and along the vein  10  toward the heart  6 . As a result, the first guide wire  20  may extend through the first lumen  40 A to pierce or otherwise interact with the valve mechanism  60  to extend therethrough, outwardly of the first tubular member  40 . In such instances, the first tubular member  40  may be inserted into the vein  10  at an acute angle with respect thereto. As such, the first tubular member  40  must bend (i.e., must be sufficiently flexible to bend) to follow the first guide wire  20  along the vein  10 . Accordingly, in some aspects, the first tubular member  40  may be configured to be selectively flexible or to otherwise be flexible only in a particular direction. For example, the first tubular member  40  may be configured to be flexible in a direction that intersects the projected travel path of the second tubular member  50 , as determined by the interaction between the first and second portions  110 ,  120  of the engagement mechanism  130  (i.e., substantially parallel to the first tubular member  40 ). As such, the first tubular member would have to be rotated about the longitudinal axis thereof in order for the first tubular member  40  to follow the first guide wire  20  along the vein  10  upon insertion of the first tubular member  40  into the vein  10 . In doing so, the appropriate positioning of the selective flexible first tubular member  40  may thus align the second tubular member  50  on an intersecting path with the vein  10 . Thus, one such benefit of the vein preparation apparatus  100  may be the alignment of the second tubular member  50  with the vein so as to reduce, minimize, or eliminate the risk of missing the vein  10  upon insertion of the second tubular member  50 . 
         [0038]      FIG. 4  further schematically illustrates the second tubular member  50 , thus aligned with the vein  10  through the insertion of the first tubular member  40  and the configuration of the engagement mechanism  130 , being advanced toward and inserted into the vein  10  in proximity to the first tubular member  40  (as also shown in  FIG. 6A ). That is, in some instances, the second tubular member  50  merely needs to be advanced toward the vein  10  for insertion therein, since the second tubular member  50  is already aligned with the vein  10  via the engagement mechanism  130  and possibly the configuration of the first tubular member  40  when inserted into the vein  10 , as previously discussed. In one aspect, the second tubular member  50  may be configured to be substantially rigid and formed of a suitable and appropriate material for insertion into a patient&#39;s body, as will be appreciated by one skilled in the art. For example, the second tubular member  50  may be comprised of a metallic material, a polymeric material, a composite material, or any other suitable and appropriate material or combinations thereof. Further, the end  90  of the second tubular member  50  is particularly configured to be capable of piercing into the vein  10 , and thus may necessarily be “sharp” since there is no pre-existing hole in the vein  10  through which the second tubular member  50  can be inserted. In one particular instance, the second tubular member  50  may essentially be configured as a hollow needle. 
         [0039]    As shown in  FIGS. 5 ,  6 B, and  6 C, once the second tubular member  50  pierces and is inserted into the vein  10 , the second tubular member  50  is advanced into intersection with the first tubular member  40  extending along the vein  10  over the first guide wire  20 . In one instance, the end  90  of the second tubular member  50  is advanced so as to pierce and enter the first tubular member  40  so as to establish communication between the respective first and second lumens  40 A,  50 A defined by the respective first and second tubular members  40 ,  50 . In another instance, the first tubular member  40  may be configured to include or otherwise define a receptor site  95  (see, e.g.,  FIGS. 6A and 9 ) at or about a predetermined intersection with the end  90  of the second tubular member  50 . For example, the receptor site  95  may comprise a relatively thinner section of the wall of the first tubular member  40 , or other factor for promoting or facilitating the insertion of the end  90  of the second tubular member  50  into the first tubular member  40 . 
         [0040]    In some aspects, the travel of the second tubular member  50  may be limited, for example, by the engagement mechanism  130  and/or a locking mechanism  140  associated with the engagement mechanism  130  and/or the first and second tubular member  40 ,  50 . For instance, the first and/or second portion  110 ,  120  of the engagement mechanism  130  may be configured to include a stop member (not shown) that limits the longitudinal travel of the second tubular member  50  with respect to the first tubular member  40 . In such a manner, the second tubular member  50  may be advanced into the vein  10  and into the first tubular member  40 , but may not be permitted to extend through the first tubular member  40  across the first lumen  40 A (i.e., the travel of the second tubular member  50  may be limited such that the end  90  does not pierce through the opposite side of the vein  10 ). 
         [0041]      FIG. 7  further schematically illustrates that the travel limitation and/or prevention of relative movement between the first and second tubular members  40 ,  50  may also be accomplished with the releasable locking mechanism  140  associated with the engagement mechanism  130  and/or the first and second tubular members  40 ,  50 . In one aspect, one of the first and second tubular members  40 ,  50  may include a protrusion  150  extending therefrom toward the other of the first and second tubular members  40 ,  50 , with the first and second tubular members  40 ,  50  being adjacently disposed through the engagement mechanism  130 . In such an aspect, the other of the first and second tubular members  40 ,  50  may include a releasable lock receptacle having a stop member  160  and a release member  170 . Accordingly, as the second tubular member  50  is advanced into the vein  10  and then into the first tubular member  40  therein, the protrusion  150  longitudinally advances to engage the release member  170  which, in some instances, may be configured to be resilient (i.e., a “spring tab”). Further advancement of the second tubular member  50  results in the depression of the release member  170 , as the protrusion  150  passes thereby toward the stop member  160 . The travel of the second tubular member  50  may then be limited or stopped when the protrusion  150  encounters the stop member  160 , at which point, the release member  170  resiliently rebounds, thereby “locking” the protrusion between the stop member  160  and the release member  170 . At this point, according to one aspect, the end  90  of the second tubular member  50  may have pierced the first tubular member  40  to establish communication between the first and second lumens  40 A,  50 A. 
         [0042]      FIGS. 6D and 8  schematically illustrates the insertion of a second guide wire  180  through the valve mechanism  70 , and then through the second lumen  50 A defined by the second tubular member  50 . Upon further advancement of the second guide wire  180 , the second guide wire  180  extends through the intersection between the first and second tubular members  40 ,  50  (i.e., via the communication between the first and second lumens  40 A,  50 A) and into the lumen  40 A defined by the first tubular member  40 . In this manner, the second guide wire  180  may be advanced to extend along the vein  10  along with the first guide wire  20 . At this point, both the first and second guide wires  20 ,  180  may extend through the end  30  of the first tubular member  40  toward the heart  6 . In this manner, the “second cannulation” of the vein  10  is essentially complete, whereby the risk of missing the vein  10  upon insertion of the second tubular member  50  is thus further reduced, minimized, or eliminated. However, the first and second tubular members  40 ,  50  may not necessarily be configured to facilitate insertion of the operative wires or leads  2 ,  3  of the pacemaker device  1 . Accordingly, aspects of the present invention further involve removing the first and second tubular members  40 ,  50  from the vein, while leaving the first and second guide wires  20 ,  180  intact and disposed with the vein  10 . 
         [0043]      FIGS. 10-14  thus schematically illustrate a configuration for allowing the withdrawal of the first and second tubular members  40 ,  50  from the vein  10 , while the first and second guide wires  20 ,  180  remain within the vein  10 . In such a configuration, the second tubular member  50  may further include a cutting member  190  associated with the end  90  of the second tubular member  50 , as shown in  FIG. 10 , wherein such a cutting member  190  may be configured to extend into the first tubular member  40  upon appropriate insertion of the end  90  of the second tubular member  60  therein. The cutting member  190  may be sufficiently “sharp” such that, upon withdrawal of the first tubular member  40  from the vein  10 , as shown in  FIG. 11  (while leaving the first guide wire  20  disposed within the vein  10 ), the cutting member  190  longitudinally divides (i.e., cuts) the first tubular member  40  from the intersection between the first and second tubular members  40 ,  50  (i.e., at the receptor site  95 ) to the end  30  of the first tubular member  40 , as shown in  FIG. 12 . That is, upon withdrawal of the first tubular member  40  from the vein  10 , the cutting member  190  associated with the end  90  of the second tubular member  50  cuts or slices the first tubular member  40  up to and through the end  30  thereof such that the first tubular member  40  is withdrawn around the second tubular member  50  and the second guide wire  180  extending therethrough. In this manner, the second tubular member  50  and the second guide wire  180  extending therethrough remain in the vein  10  alongside the first guide wire  20 , when the first tubular member  40  is withdrawn from the vein, without bending or damaging the second guide wire  180  or causing trauma to the vein  10 , as shown in  FIG. 13 . 
         [0044]    In some instances, in order to further facilitate the first tubular member  40  withdrawal process, the first tubular member  40 , from the intersection between the first and second tubular members  40 ,  50  (i.e., at the receptor site  95 ) to the end  30  of the first tubular member  40 , may be configured to define a withdrawal path  200 , as shown in  FIG. 9 . The withdrawal path  200  may comprise, for example, a relatively thinner section of the wall of the first tubular member  40 , or other factor for promoting or facilitating the longitudinal division of the first tubular member  40  by the cutting member  190  associated with the second tubular member  50 . Further, one skilled in the art will appreciate from the disclosure herein that, in order to withdraw the first tubular member  40  from the vein  10 , the locking mechanism  140  shown in  FIG. 7  must first be released, for example, by depressing the release member  170  so as to allow the protrusion  150  to be removed from between the stop member  160  and the release member  170 . Release of the locking mechanism  140  thus allows relative movement between the first and second tubular members  40 ,  50  such that the first tubular member  40  can be withdrawn from the vein  10  separately from the second tubular member  50 , as shown in  FIG. 13 . Removal or withdrawal of the first tubular member  40  from the vein  10  leaves the first and second guide wires  20 ,  180  remaining within the vein  10 , with the second guide wire  180  being disposed within and extending through the second tubular member  50 , as shown in  FIG. 13 . As such, withdrawal of the second tubular member  50  leaves both the first and second guide wires  20 ,  180  extending into and along the vein  10 , as shown in  FIG. 14 . 
         [0045]    The first and second guide wires  20 ,  180  remaining within the vein  10 , after withdrawal of the first and second tubular members  40 ,  50 , are thus configured to further facilitate the completion of the cardiac pacemaker implantation procedure, as will be appreciated by one skilled in the art. More particularly, each of the first and second guide wires  20 ,  180  may receive appropriate and respective first and second sheaths  210 ,  220  thereover such that the first and second sheaths  210 ,  220  extend into the vein  10  and toward the heart  6 , as shown in  FIG. 15 . The first and second guide wires  20 ,  180  can then be withdrawn from the vein  10 , leaving the first and second sheaths  210 ,  220  intact and disposed within the vein  10 , as shown in  FIG. 16 . The operative wires  2 ,  3 , of the pacemaker  1  can then be inserted into and through respective sheath lumens  210 A,  220 A defined by the first and second sheaths  210 ,  220  and into the vein  10 , as shown in  FIG. 17 , at which point, the leads  2 ,  3 , may be directed by the surgeon to the appropriate locations within the heart  6 . Once the leads  2 ,  3  are appropriately placed, the first and second sheaths  210 ,  220  are then withdrawn from the vein  10  and the ends of the leads  2 ,  3  external to the vein attached to the pacemaker device  1  configured to generate the electrical signals/impulses that are transmitted by the leads  2 ,  3  to the heart  6 , as shown in  FIGS. 1 and 18 . 
         [0046]    Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.