U.S. patent application number 09/747294 was filed with the patent office on 2001-09-13 for cardiac mapping and ablation systems.
Invention is credited to Kordis, Thomas F., Swanson, David K..
Application Number | 20010021867 09/747294 |
Document ID | / |
Family ID | 27364467 |
Filed Date | 2001-09-13 |
United States Patent
Application |
20010021867 |
Kind Code |
A1 |
Kordis, Thomas F. ; et
al. |
September 13, 2001 |
Cardiac mapping and ablation systems
Abstract
A probe for cardiac diagnosis and/or treatment has a catheter
tube. The distal end of the catheter tube carries first and second
electrode elements. The probe includes a mechanism for steering the
first electrode element relative to the second electrode element in
multiple directions.
Inventors: |
Kordis, Thomas F.;
(Sunnyvale, CA) ; Swanson, David K.; (Mountain
View, CA) |
Correspondence
Address: |
Daniel D. Ryan
RYAN, KEES & HOHENFELDT, S.C.
Suite 1900
633 West Wisconsin Avenue
Milwaukee
WI
53203
US
|
Family ID: |
27364467 |
Appl. No.: |
09/747294 |
Filed: |
December 21, 2000 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
09747294 |
Dec 21, 2000 |
|
|
|
08934577 |
Sep 22, 1997 |
|
|
|
6233491 |
|
|
|
|
08934577 |
Sep 22, 1997 |
|
|
|
08574995 |
Dec 19, 1995 |
|
|
|
08574995 |
Dec 19, 1995 |
|
|
|
08033681 |
Mar 16, 1993 |
|
|
|
Current U.S.
Class: |
607/112 |
Current CPC
Class: |
A61B 2018/00214
20130101; A61B 18/1492 20130101; A61B 2018/0016 20130101; A61B
2218/002 20130101; A61B 2018/00839 20130101; A61B 2018/00267
20130101; A61B 2018/00577 20130101; A61B 2018/0091 20130101; A61B
2018/1253 20130101; A61N 1/06 20130101; A61B 2018/1407 20130101;
A61B 2018/00357 20130101; A61B 2018/1435 20130101 |
Class at
Publication: |
607/112 |
International
Class: |
A61F 007/00 |
Claims
What is claimed is:
1. A probe for use within the heart to contact endocardial tissue
comprising a catheter tube having a distal end, a first electrode
element on the distal end, second electrode element on the distal
end, the second electrode element defining a three-dimensional
structure that extends along an axis and that has an open interior,
and means for moving the first electrode element within the open
interior of the second electrode element in a first direction along
the axis of the second electrode element, in a second direction
rotating about the axis of the second electrode element, and in a
third direction normal to the axis of the second electrode
element.
2. A probe according to claim 1 wherein at least one of the first
and second electrode elements is operative for emitting energy to
ablate myocardial tissue.
3. A probe according to claim 1 wherein at least one of the first
and second electrode elements is operative for sensing electrical
activity in endocardial tissue.
4. A probe according to claim 1 wherein one of the first and second
electrode elements is operative for sensing electrical activity in
endocardial tissue, and wherein the other one of the first and
second electrode elements is operative for emitting energy to
ablate myocardial tissue.
5. A probe according to claim 1 wherein at least one of the first
and second electrode elements is operative in a first mode for
sensing electrical activity in endocardial tissue and in a second
mode for emitting energy to ablate myocardial tissue.
6. A system for use within the heart to contact endocardial tissue
comprising a first probe comprising a catheter tube having a
proximal end, a distal end, and a bore extending along an axis
between the proximal and distal end, and a three dimensional
structure having an open interior area carried on the distal end of
the catheter tube, the structure having an exterior surface for
contacting endocardial tissue, a second probe comprising a guide
body having a proximal end and a distal end, the guide body being
slidably received with the catheter tube bore with the distal end
of the guide body extending beyond the distal end of the catheter
tube into the open interior area of the structure and with the
proximal end of the guide body extending beyond the proximal end of
the catheter tube, an electrode element carried on the distal end
of the guide body, and means for steering the electrode element
through the hollow interior area in a first direction along the
axis of the catheter tube bore, in a second direction rotating
about the axis of the catheter tube bore, and in a third direction
normal to the axis of the catheter tube bore.
7. A system according to claim 6 and further including means for
collapsing the structure to close the interior area and for
expanding the structure to open the interior area.
8. A system according to claim 6 and further including a second
electrode element on the exterior surface of the structure.
9. A system according to claim 8 wherein at least one of the first
and second electrode elements is operative for sensing electrical
activity in endocardial tissue.
10. A system according to claim 8 wherein the at least one of the
first and second electrode elements is operative for emitting
energy to ablate myocardial tissue.
11. A system according to claim 6 wherein the electrode element is
operative for emitting energy to ablate myocardial tissue.
12. A system according to claim 6 and further including a second
electrode element on the exterior surface operative for sensing
electrical activity in endocardial tissue.
13. A system according to claim 12 wherein the first electrode
element is operative for emitting energy to ablate myocardial
tissue.
14. A system according to claim 13 wherein the second electrode
element is further operative for emitting energy to ablate
myocardial tissue.
15. A system according to claim 6 and further including a handle
attached to the proximal end of the guide body, and wherein the
handle includes control means attached to the steering means for
remotely moving the electrode element in the third direction.
Description
FIELD OF THE INVENTION
[0001] The invention relates to systems and methods for mapping and
ablating the interior regions of the heart for treatment of cardiac
conditions.
BACKGROUND OF THE INVENTION
[0002] Physicians make use of catheters today in medical procedures
to gain access into interior regions of the body to ablate targeted
tissue areas. It is important for the physician to be able to
carefully and precisely control the position of the catheter and
its emission of energy within the body during tissue ablation
procedures.
[0003] The need for careful and precise control over the catheter
is especially critical during procedures that ablate tissue within
the heart. These procedures, called electrophysiological therapy,
are becoming more widespread for treating cardiac rhythm
disturbances.
[0004] During these procedures, a physician steers a catheter
through a main vein or artery into the interior region of the heart
that is to be treated. The physician then further manipulates a
steering mechanism to place the electrode carried on the distal tip
of the catheter into direct contact with the tissue that is to be
ablated. The physician directs energy from the electrode through
tissue to an indifferent electrode (in a uni-polar electrode
arrangement) or to an adjacent electrode (in a bi-polar electrode
arrangement) to ablate the tissue and form a lesion.
[0005] Cardiac mapping can be used before ablation to locate
aberrant conductive pathways within the heart. The aberrant
conductive pathways constitute peculiar and life threatening
patterns, called dysrhythmias. Mapping identifies regions along
these pathways, called foci, which are then ablated to treat the
dysrhythmia.
[0006] There is a need for cardiac mapping and ablation systems and
procedures that can be easily deployed with a minimum of
manipulation and effort.
[0007] There is also a need for systems and procedures that are
capable of performing cardiac mapping in tandem with cardiac
ablation. Such multipurpose systems must also be easily. introduced
into the heart. Once deployed, such multipurpose systems also must
be capable of mapping and ablating with a minimum of manipulation
and effort.
SUMMARY OF THE INVENTION
[0008] A principal objective of the invention is to provide
improved probes to carry out cardiac mapping and/or cardiac
ablation procedures quickly and accurately.
[0009] Another principal objective of the invention is to provide
improved probes that integrate mapping and ablation functions.
[0010] The invention provides a probe for use within the heart to
contact endocardial tissue. The probe includes a catheter tube
having a distal end that carries a first electrode element. The
probe also includes a second electrode element on the distal end.
The second electrode element defines a three-dimensional structure
that extends along an axis and that has an open interior. The probe
includes a mechanism for moving the first electrode element within
the open interior of the second electrode element in a first
direction along the axis of the second electrode element, in a
second direction rotating about the axis of the second electrode
element, and in a third direction normal to the axis of the second
electrode element.
[0011] In a preferred embodiment, the movable first electrode
element serves to ablate myocardial tissue. The second electrode
element independently serves to sense electrical activity in
endocardial tissue.
[0012] Other features and advantages of the inventions are set
forth in the following Description and Drawings, as well as in the
appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a side view, with portions fragmented and in
section, of an endocardial mapping system that embodies the
features of the invention, shown deployed and ready for use inside
a heart chamber;
[0014] FIG. 2 is a side view of endocardial mapping system shown in
FIG. 1, with portions fragmented and in section, showing the
electrode-carrying basket in a collapsed condition before
deployment inside the heart chamber;
[0015] FIG. 3 is an enlarged side view of the electrode-carrying
basket and movable guide sheath shown in FIG. 2, with portions
fragmented and in section, showing the electrode-carrying basket in
a collapsed condition before deployment;
[0016] FIG. 4 is an enlarged side view of the electrode-carrying
basket and movable guide sheath shown in FIG. 1, with portions
fragmented and in section, showing the electrode-carrying basket in
a deployed condition;
[0017] FIG. 5 is a side view of two splines of the basket, when
deployed, showing the arrangement of electrodes on the splines;
[0018] FIG. 6 is a section view taken generally along line 6-6 in
FIG. 1, showing the interior of the catheter body for the mapping
probe;
[0019] FIG. 7 is a plan view, with portions fragmented, of the
introducer and outer guide sheath being introduced into the vein or
artery access site in the process of forming the system shown in
FIG. 1;
[0020] FIG. 8 is a plan view of the introducer, the outer guide
sheath, and the steerable catheter being introduced into the access
site in the process of forming the system shown in FIG. 1;
[0021] FIG. 9 is a plan view of the interior of the handle for the
steerable catheter, partially broken away and in section, showing
the mechanism for steering the distal tip of the catheter body;
[0022] FIG. 10 is a side view, with portions fragmented and in
section, of advancing the steerable catheter body and outer guide
sheath into the desired heart chamber;
[0023] FIG. 10A is a plan view of the interior of the hemostatic
valve that systems embodying features of the invention use, showing
the resilient slotted membrane present within the valve;
[0024] FIG. 11 is a side view, with portions fragmented and in
section, of the guide sheath and the steerable catheter body
advanced into the deployment position within the desired heart
region;
[0025] FIG. 12 is a side view, with portions fragmented and in
section, of the mapping probe just before being introduced for
advancement within the outer guide sheath, with the hemostat sheath
fully forward to enclose the electrode-carrying basket;
[0026] FIG. 13 is a side view, with portions fragmented and in
section, of the mapping probe being advanced through the hemostatic
valve of the outer guide sheath, with the hemostat sheath fully
forward to enclose the electrode-carrying basket;
[0027] FIG. 14 is a side view, with portions fragmented and in
section, of the mapping probe after advancement through the
hemostatic valve of the outer guide sheath, with the hemostat
sheath pulled back to uncover the electrode-carrying basket;
[0028] FIG. 15 is an enlarged view, with portions in section, of
the electrode-carrying basket deployed inside the heart chamber in
use in association with a separate ablation probe;
[0029] FIG. 16 is an enlarged plan view of an alternative three
dimensional structure, partially in section, that can be deployed
using the system shown in FIG. 1, in use in association with a
separate ablation probe;
[0030] FIG. 17 is an enlarged side section view of the structure
shown in FIG. 16 in a collapsed condition before deployment;
[0031] FIG. 18 is an enlarged plan view of an alternative three
dimensional structure that can be deployed using the system shown
in FIG. 1, in use in association with a separate ablation
probe;
[0032] FIG. 19 is an enlarged side section view of the structure
shown in FIG. 18 in a collapsed condition before deployment;
[0033] FIG. 20 is a perspective view, partially fragmented, of an
alternative embodiment of an outer guide sheath having a preformed
complex curvature;
[0034] FIG. 21 is an enlarged plan view, partially in section, of
the guide sheath shown in FIG. 20 deployed inside the heart chamber
and in use in association with a separate steerable ablation
probe;
[0035] FIG. 22 is a perspective view, partially fragmented, of an
alternative embodiment of an outer guide sheath having a steerable
distal tip;
[0036] FIG. 23 is an enlarged plan view, partially in section, of
the guide sheath shown in FIG. 22 deployed inside the heart chamber
and in use in association with a separate ablation probe;
[0037] FIG. 24 is a plan view, with portions fragmented and in
section, of an integrated mapping and ablation system that embodies
the features of the invention;
[0038] FIGS. 25 and 26 are enlarged side elevation views of the
electrode-carrying basket of the mapping probe that the system
shown in FIG. 24 uses, showing the range of movement of the
steerable ablating element carried within the basket;
[0039] FIG. 27 is a diagrammatic view of the integrated mapping and
ablation system shown in FIG. 24;
[0040] FIG. 28 is an end elevation view, taken generally along line
28-28 in FIG. 26, of the electrode-carrying basket of the mapping
probe that the system shown in FIG. 24 uses, showing the range of
movement of the steerable ablating element carried within the
basket;
[0041] FIG. 29 is an enlarged side section view of the distal end
of the electrode-carrying basket of the mapping probe that the
system shown in FIG. 24 uses, showing the basket in a collapsed
condition about the steerable ablating element before
deployment;
[0042] FIG. 30 is an end section view of the collapsed basket,
taken generally along line 30-30 in FIG. 29;
[0043] FIG. 31 is a side section view of the multiple layer
catheter body of the mapping probe used in the system shown in FIG.
24;
[0044] FIG. 32 is a perspective view of the multiple layers of the
catheter body shown in section in FIG. 31;
[0045] FIG. 33 is a view, partially in section, showing the
formation of the first layer of the multiple layer catheter body
shown in FIGS. 31 and 32;
[0046] FIG. 34 is a view, partially in section, showing the
formation of the second layer of the multiple layer catheter body
shown in FIGS. 31 and 32;
[0047] FIG. 35 is a view showing the formation of the third layer
of the multiple layer catheter body shown in FIGS. 31 and 32;
[0048] FIG. 36 is a view showing the formation of the fourth layer
of the multiple layer catheter body shown in FIGS. 31 and 32;
and
[0049] FIGS. 37 and 38 are views showing the formation of the fifth
and final layer of the multiple layer catheter body shown in FIGS.
31 and 32.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0050] FIG. 1 shows an endocardial mapping system 10 that embodies
features of the invention, when deployed and ready for use within a
selected region 12 inside the heart.
[0051] The Figures generally show the selected region 12 to be the
left ventricle of the heart. However, it should be noted that the
heart shown in the Figures is not anatomically accurate. The
Figures show the heart in diagrammatic form to demonstrate the
features of the invention.
[0052] When deployed, the system 10 includes an introducer 14, an
outer guide sheath 16, and a mapping probe 18.
[0053] As FIG. 1 shows, the introducer 14 establishes access to a
vein or artery. The outer guide sheath 16 enters the access through
the introducer 14. The guide sheath 16 extends through the vein or
artery to enter the selected heart chamber 12.
[0054] Together, the introducer 14 and the outer sheath 16
establish a passageway that guides the mapping probe 18 through the
access vein or artery and into the selected heart chamber 12.
[0055] The mapping probe 18 has a handle 20 (which FIG. 12 shows in
its entirety), an attached flexible catheter body 22, and a movable
hemostat sheath 30 with associated carriage 52.
[0056] The distal end of the catheter body 22 carries a three
dimensional structure 24. In FIG. 1, the structure 24 takes the
form of a basket. FIGS. 16 and 18 show alternative structures,
which will be described in greater detail later.
[0057] The three dimensional structure of the basket 24 includes an
exterior surface 27 that encloses an open interior area 25. The
basket 24 carries a three dimensional array of electrodes 26 on its
exterior surface 27 (see FIG. 4 also).
[0058] As FIG. 1 shows, when deployed inside the heart chamber 12,
the exterior surface 27 of the basket 24 holds the electrodes 26
against the endocardial surface.
[0059] When fully deployed, the outer guide sheath 16 holds the
catheter body 22. The sheath 16 is made from an inert plastic
material. In the preferred embodiment, the sheath 16 is made from a
nylon composite material.
[0060] The sheath 16 has an inner diameter that is greater than the
outer diameter of the-catheter body 22. As a result, the sheath 16
can slide along the catheter body 22.
[0061] The proximal end of the sheath 16 includes a handle 17. The
handle 17 helps the user slide the sheath 16 along the catheter
body 22, as the arrows in FIGS. 1 and 2 depict. FIGS. 1 and 2 show
the range of sheath movement.
[0062] As FIGS. 2 and 3 show, forward movement of the handle 17
(i.e., toward the introducer 14) advances the distal end of the
slidable sheath 16 upon the basket 24. The slidable sheath 16
captures and collapses the basket 24 (as FIG. 3 also shows in
greater detail). In this position, the distal end of the sheath 16
entirely encloses the basket 24.
[0063] As FIGS. 1 and 4 show, rearward movement of the handle 17
(i.e., away from the introducer 14) retracts the slidable sheath 16
away from the basket 24. This removes the compression force. The
basket 24 opens to assume a prescribed three dimensional shape.
[0064] The basket electrodes 26 record the electrical potentials in
myocardial tissue. Connectors 44 on the handle 20 (see FIGS. 12 and
13) attach to an external processor (not shown). The processor
derives the activation times, the distribution, and the waveforms
of the potentials recorded by the basket electrodes 26.
[0065] The basket 24 can be variously constructed. In the
illustrated and preferred embodiment (best shown by FIG. 4), the
basket 24 comprises a base member 32 and an end cap 34. Generally
flexible splines 36 extend in a circumferentially spaced
relationship between the base member 32 and the end cap 34.
[0066] In the illustrated embodiment, eight splines 36 form the
basket 24. However, additional or fewer splines 36 could be used,
depending upon application.
[0067] In this arrangement, the splines 36 are made of a resilient
inert material, like Nitinol metal or silicone rubber. The splines
36 are connected between the base member 32 and the end cap 34 in a
resilient, pretensed condition.
[0068] The resilient splines 36 bend and conform to the tissue
surface they contact. As FIGS. 2 and 3 show, the splines 36 also
collapse into a closed, compact bundle in response to an external
compression force.
[0069] In the illustrated embodiment (as FIGS. 4 and 5 best show),
each spline 36 carries eight electrodes 26. Of course, additional
or fewer electrodes 26 can be used. Furthermore, one or more
electrodes 26 can also be located on the end cap 34.
[0070] The electrodes 26 can be arranged in thirty-two bi-polar
pairs, or as sixty-four uni-polar elements. In the preferred
embodiment, the electrodes 26 are made of platinum or gold plated
stainless steel.
[0071] A signal wire 38 made from a highly conductive metal, like
copper, leads from each electrode 26. The signal wires 38 extend
down the associated spline 36, by the base member 32, and into the
catheter body 22. An inert plastic sheath 40 preferably covers each
spline 36 to enclose the signal wires 38 (see FIGS. 4 and 5). In
the preferred embodiment, the sheath 40 is made of polyurethane
material.
[0072] The eight signal wires 38 for each spline 36 are twisted
together to form a common bundle 42. As FIG. 6 shows, the eight
common bundle 42 are, in turn, passed through the catheter body 22
of the mapping probe 18. The common bundles 42 extend within
catheter body 22 and into the probe handle 20.
[0073] The sixty-four signal wires 38 are distributed within the
probe handle 20 to one or more external connectors 44, as FIG. 12
shows. In the illustrated embodiment, each connector contains
thirty-two pins to service thirty-two signal wires. The connectors
44 attach to the external processor.
[0074] As FIG. 6 shows, the catheter body 22 also includes an inner
sleeve that forms a central lumen 46. The wire bundles 42 are
oriented in an equally spaced array about this lumen 46. In the
preferred embodiment, the sleeve of the central lumen 46 is made of
a Teflon material.
[0075] The proximal end of the central lumen 46 is attached to a
flushing port 48 that extends outside the handle 20, as FIG. 12
shows. The distal end of the central lumen 46 opens at the base
member 32 of the basket 24. Anticoagulant or saline can be
introduced through the flushing port 48 into the heart chamber 12
that the basket 24 occupies.
[0076] In the illustrated and preferred embodiment (as FIG. 5 best
shows), a first region 54 on the proximal end of each spline 36 is
free of electrodes 26. Likewise, a second region 56 on the distal
end of each spline 36 is also free of electrodes 26. These two fore
and aft regions 54 and 56 generally fail to make stable surface
contact with the endocardial tissue. Therefore, electrodes 26 in
these regions may not uniformly provide reliable signals.
[0077] The eight electrodes 26 on each spline 36 are arranged in 4
groups of equally spaced pairs in a third region 58 between the two
end regions 54 and 56. The third region 58 uniformly makes stable
surface contact with the endocardial tissue, creating reliable
signals from the electrodes 26.
[0078] FIGS. 7 to 14 show the details of introducing the system 10
into the heart chamber 12.
[0079] The system 10 includes a steerable catheter 60 (see FIG. 8)
to facilitate the introduction and positioning of the outer guide
sheath 16.
[0080] The catheter 60 directs the introduction of the outer guide
sheath 16, which is otherwise free of any onboard steering
mechanism. The guide sheath 16, in turn, directs the introduction
of the mapping probe 18, which is likewise free of any onboard
steering mechanism.
[0081] Use of a separate catheter 60 for steering purposes results
in a significant reduction in the overall size of the system
components.
[0082] If the mapping probe 18 carried its own onboard steering
mechanism, the catheter body 22 would have to be of sufficient size
to accommodate it. Typically, this would require a catheter body 22
with a diameter of about 12-14 French (one French is 0.33 mm in
diameter).
[0083] Furthermore, if carried onboard the mapping probe 18, the
steering mechanism would also have to be of sufficient strength to
deflect the entire structure of the basket 24 when in a collapsed
condition.
[0084] According to this aspect of the invention, use of a
separate, dedicated steerable catheter 60 permits the introduction
of the entire system 10 through the access vessel and into the
heart chamber using an outer guide sheath of about only 10 French.
The catheter body 22 of the mapping probe 18 can also be
significantly smaller, being on the order of 6 to 8 French. In
addition, a smaller steering mechanism can also be used, because
only the outer sheath 16 needs to be steered.
[0085] As FIG. 7 shows, the introducer 14 has a skin-piercing
cannula 62. The physician uses the cannula 62 to establish
percutaneous access into the selected vein or artery (which is
typically the femoral vein or artery). The other end of the
introducer 14 includes a conventional hemostatic valve 64.
[0086] The valve 64 includes a resilient slotted membrane 65 (as
FIG. 10A shows). The slotted membrane 65 blocks the outflow of
blood and other fluids from the access. The slot in the membrane 65
yields to permit the introduction of the outer guide sheath 16
through it. The resilient membrane 65 conforms about the outer
surface of the sheath 16, thereby maintaining a fluid tight
seal.
[0087] The introducer 14 also includes a flushing port 66 for
introducing anticoagulant or other fluid at the access site.
[0088] As FIG. 8 shows, the steerable catheter 60 includes a
catheter body 68 having a steerable tip 70 at its distal end. A
handle 72 is attached to the proximal end of the catheter body 68.
The handle 12 encloses a steering mechanism 74 for the distal tip
70.
[0089] The steering mechanism 74 can vary. In the illustrated
embodiment (see FIG. 9), the steering mechanism is the one shown in
Copending U.S. application Ser. No. 07/789,260, which is
incorporated by reference.
[0090] As FIG. 9 shows, the steering mechanism 74 of this
construction includes a rotating cam wheel 76 within the handle 72.
An external steering lever 78 rotates the cam wheel. The cam wheel
76 holds the proximal ends of right and left steering wires 80.
[0091] The steering wires 80 extend along the associated left and
right side surfaces of the cam wheel 76 and through the catheter
body 68. The steering wires 80 connect to the left and right sides
of a resilient bendable wire or spring (not shown) that deflects
the steerable distal tip 70 of the catheter body 68.
[0092] As FIG. 8 shows, forward movement of the steering lever 80
bends the distal tip 70 down. Rearward movement of the steering
lever 80 rearward bends the distal tip 70 up. By rotating the
handle 70, thereby rotating the distal tip 70, and thereafter
manipulating the steering lever 80 as required, it is possible to
maneuver the distal tip 70 virtually in any direction.
[0093] In an alternative arrangement (shown in phantom line view A
in FIG. 8), the steerable distal tip 70 can also be bent out of a
normal coaxial relationship with the catheter body 68 using custom
shaped wire stiffeners 71. The stiffeners 71 create a pre-formed,
complex curve configuration. The complex curvature simplifies
access to difficult-to-reach locations within the heart, such as
the aortic approach through the left ventricle to the left
atrium.
[0094] FIGS. 10 and 11 show the details of using the steerable
catheter 60 to guide the outer sheath 16 into position.
[0095] The outer guide sheath 16 includes an interior bore 82 that
receives the steerable catheter body 68 of the catheter 60. The
physician can slide the outer guide sheath 16 along the steerable
body 68 of the catheter 60.
[0096] The handle 17 of the outer sheath 16 includes a conventional
hemostatic valve 84. The valve 84, like the valve 64, includes a
resilient slotted membrane 65 (as FIG. 10A shows) that blocks the
outflow of blood and other fluids. Like the valve 64, the slotted
membrane 65 yields to permit the introduction of the body 22 of the
mapping probe 18 through it. At the same time, the membrane 65
conforms about the outer surface of the body 22 to maintain a fluid
tight seal.
[0097] Together, the valves 64 and 84 provide an effective
hemostatic system that allows a procedure to be performed in a
clean and relatively bloodless manner.
[0098] In use, the steerable catheter body 68 enters the bore 82 of
the guide sheath 16 through the valve 84, as FIG. 10 shows. The
handle 17 of the outer sheath 16 also preferably includes a
flushing port 28 for the introduction of an anticoagulant or saline
into the interior bore 82.
[0099] As FIG. 10 also shows, the physician advances the catheter
body 68 and the outer guide sheath 16 together through the access
vein or artery. The physician retains the sheath handle 17 near the
catheter handle 72 to keep the catheter tip 70 outside the distal
end of the outer sheath 16. In this way, the physician can operate
the steering lever 78 to remotely point and steer the distal end 70
of the catheter body 68 while jointly advancing the catheter body
68 and guide sheath 16 through the access vein or artery.
[0100] The physician can observe the progress of the catheter body
68 using fluoroscopic or ultrasound imaging, or the like. The outer
sheath 16 can include an radio-opaque compound, such a barium, for
this purpose. Alternatively, a radio-opaque marker can be placed at
the distal end of the outer sheath 16.
[0101] This allows the physician to maneuver the catheter body 68
through the vein or artery into the selected interior heart chamber
12, as FIG. 10 shows.
[0102] As FIG. 11 shows, when the physician locates the distal end
70 of the catheter body 68 in the desired endocardial chamber 12,
he/she slides the outer sheath handle 17 forward along the catheter
body 68, away from the handle 72 and toward the introducer 14. The
catheter body 68 directs the guide sheath 16 fully into the heart
chamber 12, coextensive with the distal tip 70.
[0103] Holding the handle 17 of the outer sheath 16, the physician
withdraws the steerable catheter body 68 from the outer guide
sheath 16.
[0104] The system 10 is now deployed in the condition generally
shown in FIG. 12. As FIG. 12 shows, the guide sheath bore 82
establishes a passageway that leads directly from the introducer 14
into the selected heart chamber 12. The mapping probe 18 follows
this passageway for deployment inside the chamber 12.
[0105] As FIG. 12 shows, before introducing the mapping probe 18,
the physician advances the hemostat sheath 30, by pushing on the
carriage 52. The sheath 30 captures and collapses the basket
24.
[0106] As FIG. 13 shows, the physician introduces the hemostat
sheath 30, with enclosed basket 24, through the hemostatic valve 84
of the outer sheath handle 17. The hemostat sheath 30 protects the
basket electrodes 26 from damage during insertion through the valve
84.
[0107] As FIG. 14 shows, when the catheter body 22 is advanced
approximately three inches into the guide sheath 16, the physician
pulls back on the sheath carriage 52 to withdraw the hemostat
sheath 30 from the valve 84. The hemostat valve 84 seals about the
catheter body 22. The guide sheath 16 now itself encloses the
collapsed basket 24.
[0108] As FIG. 2 shows, the outer sheath 16 directs the basket 24
of mapping probe 18 to the desired location inside the heart
chamber 12. As FIG. 1 shows, the physician then moves the handle 17
rearward. The distal end of the sheath 16 slides back to deploy the
basket 24 for use.
[0109] Once deployed, the physician can again collapse the basket
24 (by pushing forward on the handle 17), as FIG. 2 shows. The
physician can then rotate the sheath 16 and probe 18 to change the
angular orientation of the basket electrodes 26 inside the chamber
12, without contacting and perhaps damaging endocardial tissue. The
physician can then redeploy the basket 24 in its new orientation by
pulling back on the handle 17, as FIG. 1 shows.
[0110] The physician analyses the signals received from the basket
electrodes 26 to locate likely efficacious sites for ablation.
[0111] The physician can now takes steps to ablate the myocardial
tissue areas located by the basket electrodes 26. The physician can
accomplish this result by using an electrode to thermally destroy
myocardial tissue, either by heating or cooling the tissue.
Alternatively, the physician can inject a chemical substance that
destroys myocardial tissue. The physician can use other means for
destroying myocardial tissue as well.
[0112] The illustrated and preferred embodiment accomplishes
ablation by using an endocardial electrode to emit energy that
heats myocardial tissue to thermally destroy it. The energy is
transmitted between the endocardial electrode and an exterior
indifferent electrode on the patient.
[0113] The type of ablating energy can vary. It can, for example,
be radio frequency energy or microwave energy. The ablating energy
heats and thermally destroys the tissue to form a lesion, thereby
restoring normal heart rhythm.
[0114] Ablating energy can be conveyed to one or more electrodes 26
carried by the basket 24. In this way, one or more of the sensing
electrodes 26 on the basket 24 can also be used for tissue
ablation.
[0115] As FIG. 15 shows, an external steerable ablating probe 150
can be used in association with the basket 24. The physician steers
the probe 150 under fluoroscopic control to maneuver the ablating
element 152 into the basket 24. Once inside the basket 24, the
physician steers the ablating element 152 into contact with the
tissue region identified by the basket electrodes 26 as the likely
efficacious site for ablation. The physician then conveys ablating
energy to the element 152.
[0116] In this arrangement, the basket 24 serves, not only to
identify the likely ablation sites, but also to stabilize the
external ablating probe 150 within a confined region within the
heart chamber 12.
[0117] FIGS. 16 and 17 show an alternative configuration for a
three dimensional structure 154 that the mapping probe 18 can
carry.
[0118] In this embodiment, the structure 154 comprises a single
length of inert wire material, such a Nitinol metal wire, preformed
into a helical array. While the particular shape of the helical
array can vary, in the illustrated embodiment, the array has a
larger diameter in its midsection than on its proximal and distal
ends.
[0119] As FIG. 16 shows, the structure 154 can be used to stabilize
the external steerable ablation probe 150 in the same fashion as
the basket 24 shown in FIG. 15 does.
[0120] The structure 154 can also carry electrodes 156, like the
basket 24, for mapping and/or ablating purposes.
[0121] As FIG. 17 shows, the structure 154 can be collapsed in
response to an external compression force. The distal end of the
slidable guide sheath 16 provides this compression force to retract
and deploy the structure 154 inside the selected heart chamber,
just like the basket structure 24.
[0122] FIGS. 18 and 19 show yet another alternative configuration
for a three dimensional structure 158 that can be carried by the
mapping probe 18. In this embodiment, the structure 158 comprises
two independent loops 160 and 162 of inert wire material, such a
Nitinol metal wire.
[0123] The loop 160 nests within the loop 162. The distal ends of
the nested loops 160 and 162 are not joined. Instead, the nested
loops 160 and 162 are free to flex and bend independently of each
other.
[0124] In the illustrated configuration, the loops 160 and 162 form
right angles to each other. Of course, other angular relationships
can be used. Additional independent loops can also be included to
form the structure 158.
[0125] As FIG. 18 shows, the loop structure 158 can be used to
stabilize the external steerable probe 150 in the same fashion as
the structures 24 and 154 shown in FIGS. 15 and 16 do.
[0126] One or more of the loops 160 and 162 can also carry
electrodes 164 for mapping and/or ablating purposes.
[0127] As the previous structures 24 and 154, the structure 158 can
be collapsed in response to an external compression force, as FIG.
19 shows. The distal end of the slidable guide sheath 16 provides
this compression force to retract and deploy the structure 158
inside the selected heart chamber 12.
[0128] FIGS. 20 and 21 show an alternative embodiment of a guide
sheath 166 that can be used in association with the introducer 14
to locate a steerable ablation probe 168 inside the selected heart
chamber 12.
[0129] Unlike the guide sheath 22, the guide sheath 166 is
preformed with a memory that assumes a prescribed complex curvature
in the absence of an external stretching or compressing force.
[0130] FIG. 20 shows in phantom lines the guide sheath 166 in a
stretched or compressed condition, as it would be when being
advanced along the steerable catheter body 68 through the access
vein or artery.
[0131] Upon entering the less constricted space of the heart
chamber 12, as FIG. 21 shows, the sheath 166 assumes its complex
curved condition. The complex curve is selected to simplify access
to difficult-to-reach locations within the heart, such as through
the inferior vena cava into the right ventricle, as FIG. 21
shows.
[0132] Like the sheath 16, the sheath 166 preferably includes a
conventional hemostatic valve 169 on its proximal end. As
previously described, the hemostatic valve 169 includes a resilient
slotted membrane to block the outflow of fluids, while allowing
passage of a catheter body.
[0133] FIG. 21 shows the sheath 166 in use in association with a
steerable ablating probe 168, which enters the sheath 166 through
the hemostatic valve 169. The sheath 166, like the sheath 16,
guides the probe 168 through the access vein or artery into the
heart chamber 12.
[0134] The complex curvature of the sheath 166 more precisely
orients the steerable ablation probe 168 with respect to the
intended ablation site than the sheath 16. As FIG. 21 shows, the
complex curvature points the distal end of the sheath 166 in a
general orientation toward the intended ablation site. This allows
the physician to finally orient the ablating element 170 with the
intended site using fine steering adjustments under fluoroscopic
control.
[0135] The embodiment shown in FIGS. 20 and 21 uses the preformed
sheath 166 to provide relatively coarse steering guidance for the
ablation probe 168 into the heart chamber 12. The sheath 166
simplifies the task of final alignment and positioning of the
ablating element with respect to the precise ablation region, which
the physician can accomplish using a few, relatively fine remote
steering adjustments.
[0136] FIGS. 22 and 23 show yet another alternative embodiment of a
guide sheath 172 that can be used in association with the
introducer 14 to locate an ablation probe 174 inside the selected
heart chamber 12.
[0137] In FIGS. 22 and 23, the guide sheath 172 includes a sheath
body 176 with a steerable distal tip 178. As FIG. 22 shows, the
sheath body 176 is extruded to include a center guide lumen 180 and
two side lumens 182. Steering wires 183 extend through the side
lumens 182, which are located near the exterior surface of the body
176.
[0138] The distal ends of the steering wires 183 are attached to
the side lumens 182 at the distal tip 178 of the sheath body 176.
The proximal ends of the steering wires 183 are attached to a
steering mechanism 186 within a handle 188 attached at the proximal
end of the sheath body 176.
[0139] The steering mechanism 186 can vary. In the illustrated
embodiment, the mechanism 186 is the rotating cam arrangement shown
in FIG. 9. In this arrangement, the steering mechanism 186 includes
an exterior steering lever 190. Fore and aft movement of the
steering lever 190 deflects the distal tip 178 of the guide sheath
176, as FIG. 22 shows.
[0140] Like the sheath 16, the sheath 172 preferably includes a
conventional hemostatic valve 185 on its proximal end to block the
outflow of fluids while allowing the passage of a catheter
body.
[0141] The steerable guide sheath 172 is used in association with
the introducer 14. The physician steers the guide sheath 172
through the access vein or artery and into the selected heart
chamber 12 under fluoroscopic control, as FIG. 23 shows. The
physician then introduces the probe 174 through the center guide
lumen 180.
[0142] In this arrangement, the probe 174 can carry a mapping
structure, like those shown in FIGS. 1; 16; and 18. Alternatively
(as FIG. 23 shows), the probe 174 carries an ablating element
192.
[0143] Because the guide sheath 174 is itself the catheter body 194
of the probe 174 need not include a steering mechanism. The
catheter body 194 need only carry the electrical conduction wires
its function requires. The catheter body 194 can therefore be
downsized. Alternatively, the absence of a steering mechanism frees
space within the catheter body 194 for additional or larger
electrical conduction wires, as ablating elements using coaxial
cable or temperature sensing elements may require.
[0144] FIG. 24 shows an integrated system 86 for performing
endocardial mapping and ablation.
[0145] Like the first described system 10, the integrated system 86
includes a mapping probe 18 with sensing electrodes 26 carried by a
three dimensional basket 24. In addition, the integrated system 86
includes, as an integral part, a steerable ablating element 88 that
is carried within the open interior area 25 of the basket 24.
[0146] The ablating element 88 can be moved relative to the sensing
electrodes 26 in three principal directions. First, the ablating
element 88 moves along the axis of the mapping probe body 96.
Second, the ablating element 88 moves rotationally about the axis
of the mapping probe body 96. Third, the ablating element 88 moves
in a direction normal to the axis of the mapping probe body 96.
FIGS. 25 to 28 show the range of movement the preferred embodiment
provides.
[0147] Movement of the ablating element 88 does not effect the
contact between the sensing electrodes 26 and the endocardial
tissue. In other words, the electrodes 26 and the ablating element
88 are capable of making contact with endocardial tissue
independent of each other.
[0148] More specifically, the system 86 includes a steerable
ablation catheter 90 that is an integral part of the mapping probe
18. The ablation catheter 90 includes a steering assembly 92 with a
steerable distal tip 84. The steerable distal tip 84 carries the
ablating element 88.
[0149] As FIG. 27 shows diagrammatically, the mapping probe 18
includes a catheter body 96 through which the steering assembly 92
of the ablation catheter 90 passes during use. The proximal end of
the catheter body 96 communicates with an opening at the rear of
the handle 20. The distal end of the catheter body 96 opens into
the interior area 25 of the basket 24. A conventional hemostatic
valve 95 is located at this junction. As previously described, the
valve 95 includes a resilient slotted membrane that blocks the
outflow of fluid while allowing the passage of the steering
assembly 92.
[0150] The proximal end of the steering assembly 92 of the ablation
catheter 90 is attached to a handle 98 (as FIG. 24 best shows). By
pulling and pushing the handle 98, the physician moves the ablating
element 88 along the axis of the mapping probe body 96. By rotating
the handle 98, the physician rotates the ablating element 88 about
the axis of the mapping probe body 96.
[0151] The handle 98 further encloses a steering mechanism 74 for
the tip 84. The steering mechanism 74 for the ablating catheter 90
is the same as the steering mechanism 74 for the catheter 60 used
in the first described system 10, and thereby shares the same
reference number.
[0152] As FIG. 27 generally shows, movement of the steering lever
78 forward bends the distal tip 84, and with it, the ablating
element 88, down. Movement of the steering lever 78 rearward bends
the distal tip 84, and with it, the ablating element 88, up.
[0153] FIGS. 25 and 26 also show the movement of the distal tip 84
and element 88 through the basket 24 between a generally straight
configuration (FIG. 25) and a deflected position, placing the
ablating element 88 in contact with endocardial tissue (FIG.
26).
[0154] By coordinating lateral (i.e., pushing and pulling) movement
of the handle 98 with handle rotation and tip deflection, it is
possible to move the ablating element 88 in virtually any direction
normal to the axis of the catheter body 96, as FIG. 28 shows.
[0155] By rotating and moving the handle 98 in these ways, it is
possible to maneuver the ablating element 88 under fluoroscopic
control through the basket 24 into contact with any point of the
endocardial surface of the chamber 12. The ablating 88 can be moved
through the basket 24 to tissue locations either in contact with
the exterior surface of the basket 24 or laying outside the reach
of the basket 24 itself.
[0156] A cable 100 with an outer insulating sheath is attached to
the ablating element 88 (see FIGS. 27 and 29). The electrically
insulated cable 100 extends down the length of the steering
assembly 92. The cable 100 conveys ablating energy to the element
88.
[0157] A plug 102 attached to the proximal end of the cable 100
(see FIGS. 24 and 27) extends outside the handle 98 for connection
to a source of ablating energy (not shown).
[0158] The integrated mapping and ablation system 86 shown in FIG.
24 shares various other components and methodologies with the first
described system 10. Elements shared by the two embodiments are
given common reference numbers.
[0159] The integrated system 86 uses the same introducer 14 to
establish an access. It also uses the same outer guide sheath 16
and the same steerable catheter 60 (with steerable catheter body
68) to position the outer guide sheath 16. The outer sheath 16 is
inserted through the introducer 14 and positioned inside the heart
by the steerable catheter body 68 in the same fashion as earlier
described (and as shown in FIGS. 10 and 11).
[0160] As also earlier described (and as FIG. 2 shows), the mapping
probe 18 is guided by the outer sheath 16 into position. The
mapping probe 18 in the integrated system 86 also includes the
slidable sheath 16 to enclose and deploy the basket 24, in the same
manner as earlier described. When enclosed by the sheath 16, the
basket 24 collapses about the distal tip 94 and ablating element 88
(as FIGS. 29 and 30 show).
[0161] In use, the physician guides the mapping probe 18 with
integral ablating catheter 90 into position through the outer
sheath 16. The physician then deploys the basket 24, freeing the
ablating element 88 for use, as FIG. 24 shows.
[0162] As FIG. 24 shows, the basket structure contacts the
surrounding endocardial tissue to hold and stabilize the ablating
element 88 in a desired confined region within the heart while the
basket electrodes 26 provide mapping signals. The ablating element
88 can be remotely steered to sites identified by the basket
electrodes 26 (as FIG. 26 shows). Ablating energy can then be
applied to thermally destroy the tissue.
[0163] As in the first described embodiment, the basket electrodes
26 can be used for ablation purposes, too.
[0164] As FIGS. 31 and 32 show, the catheter body 96 of the mapping
probe 18 comprises an integral multiple layer structure. In this
structure, the signal wires 38 for the sensing electrodes 26 on the
basket 24 are imbedded within the walls of the catheter body 96.
This structure frees space at the interior of catheter body 96 to
accommodate passage of the steering assembly 92.
[0165] As FIGS. 31 and 32 show, the catheter body 96 includes a
center tube 106 made from a plastic material, such as Pebax tubing.
The center tube 106 has an interior bore 108 of a size that
accommodates the steering assembly 92 of the ablating catheter
90.
[0166] The catheter body 96 includes two layers 110 and 112 of
copper signal wire 38 (42 gauge) wrapped about the center tube 106.
Each copper signal wire 38 carries an outer insulating sheath. In
addition, the two layers 110 and 112 are separated from each other
by an insulation layer 114 of Teflon plastic or the like. The layer
114 provides an added measure of insulation between the wires 38,
particularly in regions where point contact between the overlapping
wire layers 110 and 112 could occur.
[0167] In the illustrated embodiment, where the basket 24 has
sixty-four electrodes, each layer 110 and 112 carries eight groups
of four signal wires 38. The signal wires 38 are preferably wound
helically along the length of the catheter body 96.
[0168] The catheter body 96 further includes a metalized plastic
layer 116 (such as metalized polyamide) that surrounds the second
layer 112 of signal wires 38. The layer 116 protection against
electromagnetic interference (EMI). The layer 116 is, in turn,
enclosed within an outer plastic tube 118 of a material such as
Pebax.
[0169] FIGS. 33 to 38 show a process for making the multiple layer
catheter body 96.
[0170] As FIG. 33 shows, the center tube 106 is fastened by clamps
124 to a mandrel 126. The mandrel 126 is rotated during the
assembly process. In the illustrated embodiment, the mandrel 126
rotates in a clockwise direction.
[0171] A wire holder 128 dispenses thirty-two shielded signal wires
38 in eight groups of four each. During the assembly process, the
holder 128 advances along the axis of the mandrel 126 upon a
rotating lead screw 130. In the illustrated embodiment, the lead
screw 130 is rotated clockwise to advance the holder 128 from left
to right along the axis of the rotating mandrel 126.
[0172] By synchronizing the rotation of the mandrel 126 with the
translation of the holder 128, the wire groups dispensed by the
holder 128 are helically wrapped about the center tube 106. This
forms the first layer 110 of signal wires 38 about the center tube
106.
[0173] As FIG. 34 shows, another holder 132 is advanced by the lead
screw 130 along the axis of the rotating mandrel 126. The holder
132 helically wraps insulating Teflon plastic tape 134 about the
first layer 110 of signal wires 38. This forms the added insulating
layer 114 of the catheter body 96.
[0174] As FIG. 35 shows, the wire holder 128 is again advanced by
the lead screw 130 along the axis of the rotating mandrel 126,
which during this step is rotated counterclockwise. The holder 128
dispenses thirty-two additional signal wires 38 in eight groups of
four each about the insulating layer 114. The rotating lead screw
130 advances the holder 128 from right to left while the mandrel
126 rotates counterclockwise to helically wrap the second layer 112
of signal wires 38 about the insulating layer 114, counterwound to
the first layer 110.
[0175] The counterwinding of the signal wire layers 110 and 112
provides greater torque transmission for rotating the basket 24 in
response to rotating the handle 20. While counterwinding is
preferred for this reason, the signal wire layers 110 and 112 can
be wrapped in the same direction.
[0176] As FIG. 36 shows, another holder 136 is advanced by the lead
screw 130 along the axis of the rotating mandrel 126. The holder
136 helically wraps metalized plastic material 138 about the second
wire layer 112, creating the EMI shield layer 116.
[0177] As FIG. 37 shows, another holder 140 advanced by the lead
screw 130 dispenses adhesive 142 upon the metalized layer 116.
[0178] As FIG. 38 shows, the outer sleeve 118 is pulled over the
adhesive 142 to complete the structure of the multiple layer
catheter body 96.
[0179] Various features of the invention are set forth in the
following claims.
* * * * *