U.S. patent application number 09/797531 was filed with the patent office on 2001-11-01 for lead with polymeric tubular liner for guidewire and stylet insertion.
Invention is credited to Bornzin, Gene A., Jenney, Christopher R., Morgan, Kevin L., Pianca, Anne M., Williams, Sheldon.
Application Number | 20010037136 09/797531 |
Document ID | / |
Family ID | 26899351 |
Filed Date | 2001-11-01 |
United States Patent
Application |
20010037136 |
Kind Code |
A1 |
Pianca, Anne M. ; et
al. |
November 1, 2001 |
Lead with polymeric tubular liner for guidewire and stylet
insertion
Abstract
An implantable lead for electrical stimulation of the body
includes an elongated multi-lumen tube with a distal tip electrode
having a longitudinally extending central bore. A cable conductor
is received in one lumen of the multi-lumen tube for electrical
connection to the tip electrode and an elongated polymeric tubular
liner having a coefficient of friction in the range of 0.01 to 0.20
is received in another lumen of the multi-lumen tube generally
aligned with the bore of the distal tip electrode for freely
receiving a guidewire through the tubular liner and through the
bore of the distal tip electrode. An electrically conductive
proximal pin is attached to the multi-lumen tubing distant from the
tip electrode and, in one embodiment, the cable conductor and the
proximal end of the polymeric tubular liner are attached to the
proximal pin. Initially, the guidewire is implanted into the body
along a desired trajectory. With the polymeric tubular liner
inserted, first the distal tip electrode, then the remainder of the
multi-lumen tube, are slid onto the guidewire such that the
guidewire slidably advances within the polymeric tubular liner.
Thereupon, the multi-lumen tube is advanced along the guidewire
until a desired site is achieved and the guidewire is removed from
the body and the multi-lumen tube. In another embodiment, the
distal tip electrode has no central bore but the elongated
polymeric tubular liner is axially aligned with the distal tip
electrode for freely receiving a stylet which is attached with the
distal tip electrode.
Inventors: |
Pianca, Anne M.; (Valencia,
CA) ; Bornzin, Gene A.; (Simi Valley, CA) ;
Jenney, Christopher R.; (Valencia, CA) ; Morgan,
Kevin L.; (Simi Valley, CA) ; Williams, Sheldon;
(Green Valley, CA) |
Correspondence
Address: |
PACESETTER, INC.
15900 Valley View Court
Sylmar
CA
91392-9221
US
|
Family ID: |
26899351 |
Appl. No.: |
09/797531 |
Filed: |
February 28, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60204297 |
May 15, 2000 |
|
|
|
Current U.S.
Class: |
607/122 |
Current CPC
Class: |
A61N 1/056 20130101 |
Class at
Publication: |
607/122 |
International
Class: |
A61N 001/05 |
Claims
What is claimed is:
1. An implantable lead for electrical stimulation of the body
comprising: an elongated multi-lumen tube extending between
proximal and distal ends; a distal tip electrode attached to the
distal end of the multi-lumen tube and having a longitudinally
extending central bore therethrough; a cable conductor received in
one lumen of the multi-lumen tube for electrical connection to the
tip electrode; and an elongated polymeric tubular liner having a
coefficient of friction in the range of 0.01 to 0.20 extending
between proximal and distal ends and received in another lumen of
the multi-lumen tube generally aligned with the bore of the distal
tip electrode for freely receiving a guidewire through the tubular
liner and through the bore of the distal tip electrode.
2. The implantable lead, as set forth in claim 1, comprising: an
electrically conductive proximal pin distant from the tip
electrode, wherein the cable conductor and the proximal end of the
polymeric tubular liner are attached to the proximal pin.
3. The implantable lead, as set forth in claim 1, comprising: an
electrically conductive proximal pin distant from the tip
electrode; wherein the proximal end of the first cable conductor,
the proximal end of the multi-lumen tubing, and the proximal end of
the polymeric tubular liner are all attached to the proximal pin at
a generally proximal connection; and wherein the distal end of the
first cable conductor, the distal end of the multi-lumen tubing,
and the distal end of the polymeric tubular liner are all attached
to the tip electrode at a generally distal connection.
4. The implantable lead, as set forth in claim 3, wherein the
distal connection includes: a tubular projection integral with the
tip electrode and coaxial with the longitudinally extending central
bore therethrough and extending in the proximal direction; a distal
crimp tube coaxial with the tubular projection of the tip electrode
and freely received thereover; wherein the distal end of the
polymeric tubular liner is coaxial with the tubular projection and
the distal crimp tube and slidably received between the tubular
projection and the distal crimp tube; a distal crimp sleeve
receiving the distal end of the cable conductor for protective
engagement thereof slidably received between the tubular projection
and the distal end of the polymeric tubular liner; and the distal
connection being coupled by a crimping operation which compresses
the distal crimp tube, the distal crimp sleeve, and the distal end
of the polymeric tubular liner all into mutual engagement with the
tubular projection.
5. The implantable lead, as set forth in claim 4, wherein: the
tubular projection has an integral annular flange; and a distal end
of the cable conductor is electrically connected to the annular
flange; whereby the tip electrode is electrically in common with
the proximal pin.
6. The implantable lead, as set forth in claim 3, wherein the
proximal connection includes: a tubular projection integral with
the proximal pin and coaxial therewith extending in the direction
of the distal tip electrode, the proximal pin and the tubular
projection together defining a conduit therethrough; a proximal
crimp tube coaxial with the tubular projection and freely received
in the conduit; wherein the proximal end of the polymeric tubular
liner is coaxial with the proximal pin and the proximal crimp tube
and slidably received between the tubular projection and the crimp
tube; a proximal crimp sleeve receiving the proximal end of the
cable conductor for protective engagement thereof slidably received
between the tubular projection and the proximal end of the
polymeric tubular liner; and the proximal connection being
finalized by a crimping operation which compresses the tubular
projection, the proximal crimp tube, the proximal crimp sleeve, and
the proximal end of the polymeric tubular liner all into mutual
engagement.
7. The implantable lead, as set forth in claim 1, comprising: an
electrically conductive proximal pin distant from the tip
electrode; a distal ring electrode attached to and encompassing the
multi-lumen tube at a location spaced from the distal tip
electrode; a proximal ring electrode attached to and encompassing
the multi-lumen tube at a location spaced from the proximal pin;
wherein the elongated multi-lumen tube has first, second, and third
independent longitudinally extending lumina; wherein the cable
conductor extends between proximal and distal ends and is received
in the first lumen for electrical connection at its proximal and
distal ends, respectively, to the proximal pin and to the distal
tip electrode; and wherein a second cable conductor extends between
proximal and distal ends and is received in the second lumen for
electrical connection to its proximal and distal ends,
respectively, to the proximal ring electrode and to the distal ring
electrode.
8. The implantable lead, as set forth in claim 1, wherein: the
distal tip electrode includes a tubular projection integral
therewith, coaxial with the central bore of the distal tip
electrode and extending in the proximal direction; and the distal
end of the polymeric tubular liner is fittingly received on the
tubular projection so as to be coaxial therewith.
9. The implantable lead, as set forth in claim 8, wherein: the
tubular projection includes an integral annular flange; and the
distal end of the first cable conductor is electrically connected
to the annular flange.
10. The implantable lead, as set forth in claim 1, wherein: the
proximal pin includes a tubular projection integral with the
proximal pin and coaxial therewith extending in the distal
direction, the proximal pin and the tubular projection together
defining a conduit therethrough, wherein the distal tip electrode
includes a tubular projection integral therewith, coaxial with the
central bore of the distal tip electrode and extending in the
proximal direction; and further comprising a coiled cable conductor
extending between a proximal end electrically connected with the
tubular projection of the proximal pin and a distal end
electrically connected with the tubular projection of the distal
tip electrode; and wherein the polymeric tubular liner is freely
received through the conduit and in a coaxial relationship with the
coiled cable and extending continuously between proximal pin and
the distal tip electrode.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to implantable
medical devices for providing stimulating pulses to selected body
tissue, and more particularly, to the lead assemblies connecting
such devices with the tissue to be stimulated.
BACKGROUND OF THE INVENTION
[0002] Although it will become evident to those skilled in the art
that the present invention is applicable to a variety of
implantable medical devices utilizing pulse generators to stimulate
selected body tissue, the invention and its background will be
described principally in the context of a specific example of such
devices, namely, cardiac pacemakers for providing precisely
controlled stimulation pulses to the heart. However, the appended
claims are not intended to be limited to any specific example or
embodiment described herein.
[0003] Pacemaker leads form the electrical connection between the
cardiac pacemaker pulse generator and the heart tissue which is to
be stimulated. As is well known, the leads connecting such
pacemakers with the heart may be used for pacing, or for sensing
electrical signals produced by the heart, or for both pacing and
sensing in which case a single lead serves as a bidirectional pulse
transmission link between the pacemaker and the heart. An
endocardial type lead, that is, a lead which is inserted into a
vein and guided therethrough into a cavity of the heart, includes
at its distal end an electrode designed to contact the endocardium,
the tissue lining the inside of the heart. The lead further
includes a proximal end having a connector pin adapted to be
received by a mating socket in the pacemaker. A flexible, coiled
conductor surrounded by an insulating tube or sheath typically
couples the connector pin at the proximal end and the electrode at
the distal end.
[0004] With the onset of multi chamber pacing for Congestive Heart
Failure (CHF), there has been much discussion and debate in the
medical community as to what is the most desirable lead possible
for left ventricular (LV) stimulation. The overwhelming opinion of
physicians seems to be that the "best" LV lead is the one that is
easiest to place and involves the fewest procedures and parts. As a
result of recent advancements in techniques and instrumentation,
many physicians have become convinced that a lead that is placed
with a guidewire, instead of a stylet, is superior.
[0005] Investigations have been performed on an LV lead that can be
placed using a stylet and such designs have been optimized. In an
effort to address the needs of the market as related above, a
through hole was drilled in the tip of this stylet driven LV lead
and converted into a lead intended to be placed over a guidewire.
Unfortunately, it was determined that this over-the-wire (OTW) LV
lead was no longer optimum for LV placement. Problems were
encountered which included jamming of the guidewire in the coil
when trying to advance the lead over the guidewire or when trying
to advance the guidewire through the lead. These problems were
amplified when the lead was advanced through the tortuous turns of
the veins of the left heart. This jamming was due in part to
offsetting of the coils (causing an uneven inner diameter), coil
compression, and coil elongation. As a result slidability and
trackability of the lead were severely sacrificed.
[0006] To solve this jamming problem, initially, changes to the
coil configuration were considered such as using a larger wire
diameter, increasing the inner diameter of the coil, and decreasing
the number of filars (individual wires) of the coil. Although some
of these configurations were improvements over the original design,
the improved results were actually very modest.
[0007] It was in light of the foregoing that the present invention
was conceived and is now hereby reduced to practice.
SUMMARY OF THE INVENTION
[0008] The present invention concerns an implantable lead for
electrical stimulation of the body. The implantable lead of the
invention includes an elongated multi-lumen tube with a distal tip
electrode having a longitudinally extending central bore. A cable
conductor is received in one lumen of the multi-lumen tube for
electrical connection to the distal tip electrode and an elongated
polymeric tubular liner having a coefficient of friction when
measured on steel in the range of 0.01 to 0.1 is received in
another lumen of the multi-lumen tube generally aligned with the
bore of the distal tip electrode for freely receiving a guidewire
through the tubular liner and through the bore of the distal tip
electrode. An electrically conductive proximal pin is attached to
the multi-lumen tube distant from the distal tip electrode and, in
one embodiment, the cable conductor and the proximal end of the
polymeric tubular liner are attached to the proximal pin.
Initially, the guidewire is implanted into the body along a desired
trajectory. With the polymeric tubular liner inserted, first the
distal tip electrode, then the remainder of the multi-lumen tube,
are slid onto the guidewire such that the guidewire slidably
advances within the polymeric tubular liner. Thereupon, the
multi-lumen tube is advanced along the guidewire until a desired
site is achieved and the guidewire is removed from the body and the
multi-lumen tube. In another embodiment, the distal tip electrode
has no central bore but the elongated polymeric tubular liner is
axially aligned with the distal tip electrode for freely receiving
a stylet and is attached with the distal tip electrode.
[0009] Due to the limited success achieved when changing the coil
configuration and insulation as mentioned above, the present
invention resulted from the investigation of an entirely new lead
configuration. Instead of using a coil as a liner for guidewire
passage, it was decided to investigate use of a liner composed of a
suitable polymer with a low coefficient of friction such as
polytetrafluoroethylene (PTFE), better known, perhaps, under the
trademark TEFLON.RTM., or equivalent. PTFE has a very low
coefficient of friction, it elongates minimally under an axial
load, and in tubular form has a uniform inner and outer diameter.
In vitro and in vivo testing of a silicone lead with a PTFE liner
has proved to be very successful. The lead does not jam on the
guidewire and the lead tracks in a satisfactory manner over the
guidewire through the tortuous bends of the veins of the left
heart. Both in vitro and in vivo testing of a polyurethane lead
with a PTFE liner have proved successful as well.
[0010] In one embodiment of a LV OTW lead with a PTFE liner, the
PTFE liner is removable. In such an embodiment, the lead is
successfully placed over a guidewire. Next the guidewire is removed
and, finally, the PTFE liner is removed. This allows for loading of
the liner with barium sulfate or bismuth subcarbonate to increase
visibility of the lead under x-ray. These compounds are not
commonly used in permanently implanted devices.
[0011] In another embodiment, the PTFE liner is placed in the inner
diameter of a coil. This prevents the problems that were
encountered, as discussed above, with the coil, yet allows for the
coil to service the distal tip electrode. Furthermore, the coil
increases the visibility of the lead under x-ray. In this
embodiment, the PTFE liner may be removed following final placement
of the lead.
[0012] In another embodiment the lead includes two cable
conductors. In this embodiment, one cable conductor services the
distal ring electrode (in contrast with a current design which
employs tri-lumen tubing receiving two cable conductors) and the
other cable conductor services the distal tip electrode. Due to the
fact that the cable conductor is not coaxial with the distal tip
electrode or the connector pin, a unique electrical connection is
required.
[0013] Due to the fact that a PTFE liner can be of thinner wall
thickness than a coil liner, the overall diameter of a lead
embodying the teachings of the present invention can be decreased.
This is a desirable feature, especially in the small distal and
tributary veins of the left heart. Also, as a result of the smaller
diameter, two leads may be placed in the larger veins of the left
heart such as the coronary sinus, great cardiac vein, and posterior
cardiac vein.
[0014] Another embodiment is to use the PTFE liner in a stylet
placeable lead. This helps to increase trackability and
steerability when placing a left sided lead that is stylet driven
for those customers who prefer stylet driven left heart leads. This
allows for a decreased overall diameter of right sided leads. With
this construction, a smaller introducer can be used to place one
lead. The same size introducer used today for placing one lead can
thereby be used to place two leads, with the lead being less
occlusive to the veins entering the heart.
[0015] A primary feature, then, of the present invention is the
provision of an improved lead assembly for implantable medical
devices providing stimulating pulses to selected body tissue.
[0016] Another feature of the present invention is the provision of
such a lead assembly with an elongated polymeric liner for
insertion of a guidewire for enhanced trackability and steerability
of the lead.
[0017] Yet another feature of the present invention is the
provision of such a lead assembly wherein the polymeric liner has a
coefficient of friction in the range of 0.01 to 0.2.
[0018] Still another feature of the present invention is the
provision of such a lead assembly wherein the polymeric liner is
loaded with a radio opaque substance to increase lead visibility
under x-ray.
[0019] Yet another feature of the present invention is the
provision of such a lead assembly with a polymeric liner that can
be fully removed after placement of the lead.
[0020] Still a further feature of the present invention is the
provision of such a lead assembly with a polymeric liner inside the
inner diameter of a conductor coil provided for electrically
servicing the distal tip electrode.
[0021] Yet a further feature of the present invention is the
provision of such a lead assembly with a polymeric liner that has a
unique electrical connection between a non coaxial cable conductor
and the distal tip electrode.
[0022] Still another feature of the present invention is the
provision of such a lead assembly with a polymeric liner that has a
unique electrical connection between a non coaxial cable and the
proximal connector pin.
[0023] Another feature of the present invention is the provision of
such a lead assembly with a polymeric liner that has a reduced
diameter for optimum placement in the small distal and tributary
veins of the left heart.
[0024] A further feature of the present invention is the provision
of such a lead assembly with a polymeric liner that has a reduced
diameter to allow for placement of more than one lead in the veins
of the left heart.
[0025] Still another feature of the present invention is the
provision of such a lead assembly with a polymeric liner for
insertion of a stylet for enhanced trackability and steerability of
the lead.
[0026] Yet another feature of the present invention is the
provision of such a lead assembly with a polymeric liner for
insertion of a stylet and placement in the right heart with a
decreased overall diameter.
[0027] Other and further features, advantages, and benefits of the
invention will become apparent in the following description taken
in conjunction with the following drawings. It is to be understood
that the foregoing general description and the following detailed
description are exemplary and explanatory but are not to be
restrictive of the invention. The accompanying drawings which are
incorporated in and constitute a part of this invention, illustrate
one of the embodiments of the invention, and together with the
description, serve to explain the principles of the invention in
general terms. Like numerals refer to like parts throughout the
disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The foregoing aspects and other features of the present
invention are explained in the following description, taken in
connection with the accompanying drawings, wherein:
[0029] FIG. 1 illustrates an implanted system for providing
electrical stimulation of a heart employing an implanted lead
embodying the present invention;
[0030] FIG. 2 is a side elevation view, in section, of one
embodiment of the implanted lead embodying the present
invention;
[0031] FIG. 3 is a cross-section view taken generally along the
line 3--3 in FIG. 2;
[0032] FIG. 4 is a detail cross-section view of a distal end of the
implanted lead illustrated in FIG. 2;
[0033] FIG. 4A is a detail perspective view of components
illustrated in FIG. 4;
[0034] FIG. 5 is a detail cross-section view of the proximal end of
the implanted lead illustrated in FIG. 2;
[0035] FIG. 5A is a detail perspective view of components
illustrated in FIG. 5;
[0036] FIG. 6 is a detail cross-section view of an intermediate
portion of the implanted lead illustrated in FIG. 2;
[0037] FIGS. 7A, 7B, and 7C are side elevation views, in section,
illustrating another embodiment of the implanted lead of the
present invention and, specifically, its configuration following
successive steps in it use;
[0038] FIG. 8 is a side elevation view, in section, of still
another embodiment of the implanted lead embodying the present
invention; and
[0039] FIG. 9 is a side elevation view, in section, of yet another
embodiment of the implanted lead embodying the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0040] In FIG. 1, there is shown a diagrammatic perspective view of
an implanted system 20 for providing electrical stimulation of a
heart 22 incorporating features of the present invention. Although
the present invention will be described with reference to the
embodiments shown in the drawings and described in the text, it
should be understood that the present invention can be embodied in
many alternate forms or embodiments. In addition, any suitable
size, shape or type of elements or materials could be used.
[0041] In FIG. 1, there is also illustrated an implantable lead 24
embodying the invention for stimulation of the body, the heart 22
in this instance, by means of a pacemaker 26 or other suitable
pulse generating device. As seen in FIGS. 1, the lead 24 is
inserted via the superior vena cava, SVC, into the coronary sinus
ostium, CS os, located in the right atrium, RA, then advanced
through the coronary sinus, CS, and placed into a tributary of the
coronary sinus, preferably the great Cardiac Vein, GVC, or the left
posterior cardiac vein (not shown), or other vein accessible from
the coronary sinus. From this location, the lead 24 can be used to
stimulate the left ventricle LV.
[0042] As shown in FIGS. 2 and 3, the lead 24 includes an elongated
multi-lumen tube 28 extending between proximal and distal ends 30,
32, respectively. A distal tip electrode 34 is suitably attached
via a tubular spacer 35 to the distal end of the multi-lumen tube
which, as illustrated, has a primary longitudinally extending
primary lumen 36 and a pair of secondary lumina 38, 40,
respectively. The tubular spacer may be bonded to the distal tip
electrode with medical adhesive and may be attached to the
multi-lumen tube using a butt joint. The distal tip electrode 34
itself has a longitudinally extending central bore 42 therethrough
which is aligned with but longitudinally spaced from distal ends of
the lumina 36, 38, and 40.
[0043] The lead 24 extends between an electrically conductive
proximal pin 44 intended for connection with the pacemaker 26 and
the distal tip electrode 34. A cable conductor 46 is received in
the secondary lumen 38 of the multi-lumen tube 28 for electrical
connection with, and extending between, the proximal pin 44 and the
distal tip electrode 34.
[0044] An elongated polymeric tubular liner 48 having a coefficient
of friction in the range of 0.01 to 0.20 extends between proximal
and distal ends of the lead 24 and is received in the primary lumen
36 of the multi-lumen tube 28 and is generally aligned with the
central bore 42 of the distal tip electrode 34. A primary function
of the polymeric tubular liner 48 is to freely receive a guidewire
50 through its passageway 52 and through the central bore 42 of the
distal tip electrode 34. Normally, the guidewire is first implanted
along the route subsequently intended for the lead 24, then the
lead is introduced onto the guidewire and advanced, or tracked, to
its final position. In this instance, the low coefficient of
friction of the polymeric tubular liner 48 greatly facilitates the
insertion process as compared with the use of previously known lead
constructions.
[0045] The liner 24, as earlier mentioned, is preferably composed
of a suitable slippery polymer such as polytetrafluoroethylene
(PTFE), better known, perhaps, under the trademark TEFLON.RTM., or
equivalent. PTFE has a very low coefficient of friction, it
elongates minimally under an axial load, and in tubular form has a
uniform inner and outer diameter. In vitro and in vivo testing of a
silicone lead with a PTFE liner has proved to be very successful.
The lead does not jam when using a guidewire and the lead tracks in
a satisfactory manner over the guidewire through the tortuous bends
of the veins of the left heart.
[0046] The proximal end of the cable conductor 46, the proximal end
of the multi-lumen tubing 28, and the proximal end of the polymeric
tubular liner 48 are all attached to the proximal pin 44 at a
proximal connection 54. Further, the distal end of the cable
conductor 46, the distal end of the multi-lumen tubing 28, and the
distal end of the polymeric tubular liner 48 are all attached to
the distal tip electrode 34 at a distal connection 56.
[0047] As best illustrated in FIG. 4, the distal connection 56
includes a tubular projection 58 extending in the proximal
direction, integral with the distal tip electrode 34 and coaxial
with the longitudinally extending central bore 42 through the
distal tip electrode. A distal crimp tube 60 is coaxial with the
tubular projection 58 and, initially, is freely received over the
tubular projection in a telescoping manner. The distal end of the
polymeric tubular liner 48 is coaxial with the tubular projection
and the distal crimp tube and is slidably received between the
tubular projection and the distal crimp tube.
[0048] As seen in FIG. 4A, a distal crimp sleeve 62, which may be
longitudinally split, receives the distal end of the cable
conductor 46 for protective engagement of the cable conductor. The
crimp sleeve 62 may first be mechanically joined to the end of the
cable conductor or the crimp sleeve and cable conductor may
continue to be loosely connected. In either event, the connected
pair of the crimp sleeve and cable conductor are then slidably
received between the tubular projection 58 and the distal end of
the polymeric tubular liner 48. Thereupon, the distal connection 56
is finalized by a crimping operation which compresses the distal
crimp tube 60, the distal crimp sleeve 62, and the distal end of
the polymeric tubular liner 48 all into mutual engagement with the
tubular projection 58. A firm unitary construction results.
[0049] Additionally, the tubular projection 58 includes an integral
annular flange 64 of enlarged transverse dimension as compared with
the dimension of the tubular projection. A distal end of the cable
conductor is electrically connected to the annular flange as by a
weld 68 such that the distal tip electrode 34 is electrically in
common with the proximal pin 44.
[0050] Turning now especially to FIG. 5, the proximal connection 54
includes a tubular projection 70 integral with the proximal pin 44,
of reduced transverse dimension, and coaxial with the proximal pin
extending in the direction of the distal tip electrode 34. The
proximal pin 44 and the tubular projection 70 together define a
coextensive conduit 72. A proximal crimp tube 74 is coaxial with
the tubular projection 70 and is freely received in the conduit.
Viewing FIG. 5A, a proximal crimp sleeve 74, generally similar to
the distal crimp sleeve 62 and, as such, longitudinally split,
receives the proximal end of the cable conductor 46 for protective
engagement of the cable conductor and that combination is slidably
received in a longitudinal bore 78 formed in the tubular projection
70. As with the construction of the distal connection 56, the crimp
sleeve 74 may first be mechanically joined to the proximal end of
the cable conductor 46 or the combination may continue to be
loosely connected. In either event, the connected pair of the crimp
sleeve 74 and the cable conductor 46 are then slidably received
within the longitudinal bore 78. Thereupon, the proximal connection
54 is finalized by a crimping operation which compresses the
proximal crimp tube 74, the proximal crimp sleeve 76, and the
proximal end of the polymeric tubular liner 48 all into mutual
engagement with the tubular projection 70. Again, a firm unitary
construction results. When the proximal pin 44 is connected to the
pacemaker 26 in the customary fashion, a suitable resilient
connector seal 80 received on the tubular projection 70 serves to
isolate the interior of the pacemaker from the intrusion of body
fluids and the like.
[0051] As particularly well seen in FIGS. 2, 4 and 5, a distal ring
electrode 82 is fittingly attached to and encompasses the
multi-lumen tube 28 at a location spaced from the distal tip
electrode 34. A proximal ring electrode 84 is fittingly attached to
and encompasses the tubular projection 70 with an insulation band
85 interposed between the proximal ring electrode and the tubular
projection for electrically isolating the two components. It was
earlier mentioned that the cable conductor 46 extends between
proximal and distal ends and is received in the lumen 38 for
electrical connection at its proximal and distal ends,
respectively, to the proximal pin 44 and to the distal tip
electrode 34. In a similar manner, a second cable conductor 86
extends between proximal and distal ends and is received in the
lumen 40 (FIG. 3) for electrical connection of its proximal and
distal ends, respectively, to the proximal ring electrode 84 and to
the distal ring electrode 82. The cable conductor 86 may be
terminated to the proximal ring electrode in a manner similar to
that of the cable conductor 46 to the tubular projection 70.
Completing the proximal connection 54 is a flexible connector boot
88 which fittingly overlies both an end of the proximal ring
electrode 84 and the proximal end of the multi-lumen tube 28. A
suitable medical adhesive backfill 89 is received between the
connector boot 88 and the polymeric tubular liner 48 to provide a
bond between the connector proximal connector ring 84 and the
multi-lumen tube although in the instance that the polymeric
tubular liner 48 is removable, as will be discussed below, the
medical adhesive backfill would not be employed.
[0052] At its distal end, as seen in FIG. 6, the cable conductor 86
advances through the lumen 40, extends through an aperture 90 in
the wall of the multi-lumen tube 28, and is welded as at 92 to its
associated distal ring electrode 82 which overlies the
aperture.
[0053] Turn now to FIGS. 7A, 7B and 7C for the description of an
embodiment of an LV OTW lead with an elongated polymeric liner
which is removable. In this instance, an implantable lead 94 is
similar to the lead 24 except for certain modifications at the
distal and proximal ends. Reference numerals will be unchanged
unless there is a change in the construction of a component. As
before, the distal tip electrode 34 includes a tubular projection
58 integral therewith coaxial with the central bore 42 and
extending in the proximal direction. Also, the tubular projection
58 includes an integral annular flange 64 to which the distal end
of the cable conductor 46 is electrically connected. At this distal
end, no crimping operation is effected as earlier described.
Rather, the distal end of the polymeric tubular liner 48 is
fittingly, coaxially, received on the tubular projection 58. At the
proximal end of the lead 94, the polymeric tubular liner 48 is
slidably contained in the conduit 72 and, as at the distal end, no
crimping operation is effected.
[0054] In this embodiment, viewing FIG. 7A, the lead is
successfully placed over a guidewire 50. Next, viewing FIG. 7B, the
guidewire 50 is removed and, finally, viewing FIG. 7C, the
polymeric liner 48 is removed. This construction allows for loading
of the polymer with barium sulfate or bismuth subcarbonate,
compounds are not commonly used in permanent devices, to increase
visibility of the lead under x-ray.
[0055] Turn now to FIG. 8 for still another embodiment of the
invention. In this instance, the polymeric liner is placed in the
inner diameter of a coil 96 which extends from a distal end
fittingly received on the tubular projection 58 and a proximal end
fittingly received on the tubular projection 70 of the proximal pin
44. This construction prevents the problems that were discussed
above with the unmodified coil, yet allows for the coil to service
the distal tip electrode 34. Furthermore the coil 96 increases the
visibility of the lead 98 under x-ray. In this embodiment the
polymeric liner 48 may be removed following final placement of the
lead 98 in the body, although it may also remain in place.
[0056] Turn now to FIG. 9 for yet another embodiment of the
invention. In this instance, the polymeric liner 48 is employed in
conjunction with a stylet placeable implantable lead 100. The
distal end of the elongated polymeric tubular liner 48 is attached
to a cylindrical projection 102 of a modified distal tip electrode
104 having no central bore 42 in contrast to the distal tip
electrode 34 although, alternatively, it may continue to have a
central bore. In this manner, the distal end of the elongated
polymeric tubular liner 48 is generally aligned with the distal tip
electrode 104. Thereupon, using a stylet knob 106 in a known
manner, an elongated stylet 108 is inserted into, and advanced in
slidable engagement with, the passageway 52 of the polymeric
tubular liner. Then, using the stylet 106, the lead 100 is advanced
into the body along the desired trajectory until a desired site is
achieved. Thereafter, the stylet is detached from the distal tip
electrode and removed from the lead and, if desired, the polymeric
tubular liner may also be removed from the lead.
[0057] It should be understood that the foregoing description is
only illustrative of the invention. Various alternatives and
modifications can be devised by those skilled in the art without
departing from the invention. Accordingly, the present invention is
intended to embrace all such alternatives, modifications and
variances which fall within the scope of the appended claims.
* * * * *