U.S. patent application number 15/297358 was filed with the patent office on 2017-02-09 for fabric electrode head.
The applicant listed for this patent is St. Jude Medical, Atrial Fibrillation Division, Inc.. Invention is credited to Kedar Ravindra Belhe, Hong Cao, Saurav Paul, Riki Thao.
Application Number | 20170035491 15/297358 |
Document ID | / |
Family ID | 39585079 |
Filed Date | 2017-02-09 |
United States Patent
Application |
20170035491 |
Kind Code |
A1 |
Paul; Saurav ; et
al. |
February 9, 2017 |
FABRIC ELECTRODE HEAD
Abstract
An electrode head is disclosed that utilizes electrically
conductive or dissipative fabric to exchange electrical energy with
tissue. This electrode head may be used for any appropriate
application, such as a catheter electrode, a return electrode, or
the like. Any appropriate function may be provided by this
electrode head, such as tissue ablation, tissue mapping, or
providing an electrical ground.
Inventors: |
Paul; Saurav; (Shoreview,
MN) ; Thao; Riki; (Little Canada, MN) ; Cao;
Hong; (Maple Grove, MN) ; Belhe; Kedar Ravindra;
(Minnetonka, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
St. Jude Medical, Atrial Fibrillation Division, Inc. |
St. Paul |
MN |
US |
|
|
Family ID: |
39585079 |
Appl. No.: |
15/297358 |
Filed: |
October 19, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14076400 |
Nov 11, 2013 |
9474566 |
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15297358 |
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11618557 |
Dec 29, 2006 |
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14076400 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 2018/00577
20130101; A61B 18/14 20130101; A61N 1/0464 20130101; A61B
2018/00071 20130101; A61N 1/05 20130101; A61B 2018/1405 20130101;
A61B 18/16 20130101; A61B 2018/0016 20130101; A61B 2018/00065
20130101 |
International
Class: |
A61B 18/14 20060101
A61B018/14; A61N 1/05 20060101 A61N001/05; A61B 18/16 20060101
A61B018/16 |
Claims
1.-20. (canceled)
21. A tissue electrode system, comprising: an elongated catheter
body having a distal end adapted for disposition within a patient
body; a generally cylindrical fabric electrode formed of woven
threads attached to said distal end of said elongated catheter
body, wherein at least a portion of said woven threads are
electrically conductive and electrically connectable with an
electrical energy source, said fabric electrode including: a first
segment having a first level of electrical conductivity; and a
second segment axially disposed relative to said first segment in a
length dimension of said generally cylindrical fabric electrode and
having a second level of electrical conductivity different than
said first level of electrical conductivity.
22. The tissue electrode system of claim 21, wherein said first
level of electrical conductivity is one of electrically conductive
and electrically dissipative and said second level of electrical
conductivity is electrically non-conductive.
23. The tissue electrode system of claim 22, herein said first
level of electrical conductivity comprises an electrical
conductivity of greater than 10.sup.-9 S/m (Siemens per meter) and
said second level of electrical conductivity comprises an
electrical conductivity of less than 10.sup.-9 S/m.
24. The tissue electrode system of claim 21, wherein said first
segment is disposed distally relative to said second segment.
25. The tissue electrode system of claim 21, wherein said second
segment is disposed distally relative to said first segment.
26. The tissue electrode system of claim 21, wherein said first
segment and said second segment are disposed in an end-to end
relation.
27. The tissue electrode system of claim 21, wherein said generally
cylindrical fabric electrode cantilevers from said distal end of
said elongated catheter body free of internal support.
28. The tissue electrode system of claim 27, wherein said elongated
catheter body further comprises: at least a first fluid conduit
extending through a portion of said elongated catheter body and
exiting through said distal end of said elongated catheter
body.
29. The tissue electrode system of claim 28, wherein said woven
threads are porous to permit fluid from said first fluid conduit to
pass into and through said generally cylindrical fabric
electrode.
30. The tissue electrode system of claim 29, wherein an entirety of
a proximal peripheral edge of said generally cylindrical fabric
electrode is fixedly attached to said distal end of said elongated
catheter body and around said first fluid conduit.
31. The tissue electrode system of claim 21, wherein said generally
cylindrical fabric electrode further comprises multiple layers of
fabric.
32. The tissue electrode system of claim 21, wherein: said first
segment of said fabric electrode comprises a first substantially
cylindrical fabric layer; and said second segment of said fabric
electrode comprises a second substantially cylindrical fabric
layer, wherein said second substantially cylindrical fabric layer
is at least partially disposed within an interior of said first
substantially cylindrical fabric layer.
33. The tissue electrode system of claim 21 further comprising: a
core extending from said distal end of said elongated catheter
body, wherein said core is disposed within an interior of said
generally cylindrical fabric electrode.
34. The tissue electrode system of claim 33, wherein said core
further comprises: an internal conduit connected to a fluid conduit
extending through a portion of said elongated catheter body.
35. The tissue electrode system of claim 34, wherein said core has
a porous length disposed within the interior of said generally
cylindrical fabric electrode.
36. The tissue electrode system of claim 35, wherein said porous
length comprises a plurality of fluid ports extending between said
internal conduit and an outside surface of said core.
37. The tissue electrode system of claim 21, further comprising: a
plurality of said second segments attached to said first
segment.
38. The tissue electrode system of claim 21, wherein each of said
plurality of second segments cantilever from a distal end of said
first segment.
39. The tissue electrode system of claim 21, wherein said first
segment has a first diameter and said second segment has a second
diameter, wherein said first and second diameter are different.
40. The tissue electrode system of claim 39, wherein said second
segment is distally disposed to said first segment and said second
diameter is less than said first diameter.
Description
CROSS-REFERENCE
[0001] This application is a continuation application of U.S.
patent application Ser. No. 14/076,400, filed 11 Nov. 2013, which
is a divisional application of U.S. patent application Ser. No.
11/618,557, filed Dec. 29, 2006, the entire contents of which is
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] a. Field of the Invention
[0003] The instant invention generally relates to the field of
electrodes. In particular, the instant invention is directed to a
tissue electrode head that incorporates fabric for exchanging
electrical energy with tissue.
b. Background Art
[0004] Catheters have been in use for medical procedures of many
years. Catheters can be used for medical procedures to examine,
diagnose, and treat while positioned at a specific location within
the body that is otherwise inaccessible without more invasive
procedures. During these procedures a catheter is insetted into a
vessel located near the surface of a human body and is guided to a
specific location within the body for examination, diagnosis, and
treatment. For example, one procedure often referred to as
"catheter ablation" utilizes a catheter to convey an electrical
stimulus to a selected location within the human body to create
tissue necrosis. Another procedure oftentimes referred to as
"mapping" utilizes a catheter with sensing electrodes to monitor
various forms of electrical activity in the human body.
[0005] In a normal heart, contraction and relaxation of the heart
muscle (myocardium) takes place in an organized fashion as
electrochemical signals pass sequentially through the myocardium
from the sinoatrial (SA) node located in the right atrium to the
atrialventricular (AV) node and then along a well defined route
which includes the His-Purkinje system into the left and right
ventricles. Sometimes abnormal rhythms occur in the atrium which
are referred to as atrial arrhythmia. Three of the most common
arrhythmia are ectopic atrial tachycardia, atrial fibrillation, and
atrial flutter. Arrhythmia can result in significant patient
discomfort and even death because of a number of associated
problems, including the following: (1) an irregular heart rate,
which causes a patient discomfort and anxiety; (2) loss of
synchronous atrioventricular contractions which compromises cardiac
hemodynamics resulting in varying levels of congestive heart
failure; and (3) stasis of blood flow, which increases the
vulnerability to thromboembolism. It is sometimes difficult to
isolate a specific pathological cause for the arrhythmia although
it is believed that the principal mechanism is one or a multitude
of stray circuits within the left and/or right atrium. These
circuits or stray electrical signals are believed to interfere with
the normal electrochemical signals passing from the SA node to the
AV node and into the ventricles. Efforts to alleviate these
problems in the past have included significant usage of various
drugs. In some circumstances drug therapy is ineffective and
frequently is plagued with side effects such as dizziness, nausea,
vision problems, and other difficulties.
[0006] An increasingly common medical procedure for the treatment
of certain types of cardiac arrhythmia and atrial arrhythmia
involves the ablation of tissue in the heart to cut off the path
for stray or improper electrical signals. Such procedures are
performed many times with an ablation catheter. Typically, the
ablation catheter is inserted in an artery or vein in the leg,
neck, or arm of the patient and threaded, sometimes with the aid of
a guidewire or introducer, through the vessels until a distal tip
of the ablation catheter reaches the desired location for the
ablation procedure in the heart. The ablation catheters commonly
used to perform these ablation procedures produce lesions and
electrically isolate or render the tissue non-contractile at
particular points in the cardiac tissue by physical contact of the
cardiac tissue with an electrode of the ablation catheter and
application of energy. The lesion partially or completely blocks
the stray electrical signals to lessen or eliminate arrhythmia.
[0007] One difficulty in obtaining an adequate ablation lesion
using conventional ablation catheters is the constant movement of
the heart, especially when there is an erratic or irregular heart
beat. Another difficulty in obtaining an adequate ablation lesion
is caused by the inability of conventional catheters to obtain and
retain uniform contact with the cardiac tissue across the entire
length of the ablation electrode surface. Without such continuous
and uniform contact, any ablation lesions formed may not be
adequate.
[0008] It is well known that benefits may be gained by forming
lesions in tissue if the depth and location of the lesions being
formed can be controlled. In particular, it can be desirable to
elevate tissue temperature to around 50.degree. C. until lesions
are formed via coagulation necrosis, which changes the electrical
properties of the tissue. For example, when sufficiently deep
lesions are formed at specific locations in cardiac tissue via
coagulation necrosis, undesirable ventricular tachycardias and
atrial flutter may be lessened or eliminated. "Sufficiently deep"
lesions means transmural lesions in some cardiac applications.
[0009] One difficulty encountered with existing ablation catheters
is assurance of adequate tissue contact. Current techniques for
creating continuous linear lesions in endocardial applications
include, for example, dragging a conventional catheter on the
tissue, using an array electrode, or using pre-formed electrodes.
All of these devices comprise rigid electrodes that do not always
conform to the tissue surface, especially when sharp gradients and
undulations are present, such as at the ostium of the pulmonary
vein in the left atrium and the isthmus of the right atrium between
the inferior vena cava and the tricuspid valve. Consequently,
continuous linear lesions can be difficult to achieve. With a rigid
catheter, it can be difficult to maintain sufficient contact
pressure until an adequate lesion has been formed. This problem is
exacerbated on contoured or trabecular surfaces. If the contact
between the electrode and the tissue cannot be properly maintained,
a quality lesion may not be formed.
[0010] There are additional issues relating to some current
ablation electrode designs. Certain ablation electrodes may char
tissue and/or cause coagulation in a very short time, even when
being operated in a low-power mode. Ablation electrodes may of
course be operated in a high-power mode as well. The resulting
elevated temperature of the ablation electrode itself may also have
an adverse effect on the ablation electrode. In this regard, at
least some ablation electrodes offer fluid cooling. Relatively high
flow rates (e.g., 70 ml per minute) are typically used for these
ablation electrodes to provide an effective cooling. This may be
disadvantageous in one or more respects. Moreover, the flow ports
are prone to becoming blocked and/or obstructed, which of course
has an adverse effect on the ability of the fluid to cool the
ablation electrode to the desired temperature. In this regard,
increased contact pressure between the ablation electrode and the
target tissue may be used to increase the potential for realizing
an adequate electrical coupling, but this may increase the
potential for flow port blockage and/or obstruction. Reduced
contact pressures may reduce the potential for flow port blockage
and/or obstruction, but this may degrade the electrical coupling
between the ablation electrode and the tissue since the cooling
fluid exiting the ablation electrode may become diluted by bodily
fluids.
BRIEF SUMMARY OF THE INVENTION
[0011] Various aspects of the present invention that will be
addressed herein relate to a tissue electrode head--an electrode
head that is intended to at least electrically interface with
tissue (e.g., while in contact with or when spaced from the
tissue). Each such tissue electrode head may be characterized as
exchanging electrical energy with the tissue at the desired time.
Generally, the tissue electrode head may be of any appropriate
type. For instance, the tissue electrode head may be in the form of
a catheter electrode. Another option is for the tissue electrode
head to be in the form of a ground patch or the like that
interfaces with the patient's skin (e.g., interfaces with an
exterior surface of the patient). The tissue electrode head may
also provide any appropriate function or combination of functions.
One embodiment has the tissue electrode head in the form of an
active electrode to provide a desired function (e.g., tissue
ablation; tissue mapping; electrical energy source). Another
embodiment has the tissue electrode head in the form of a return
electrode to provide an electrical ground. The electrode head may
apply electrical energy to a single location (e.g., for spot tissue
ablation), or may apply electrical energy to tissue while being
moved relative to the tissue (e.g., to create a linear lesion).
Furthermore, the tissue electrode head may be of either a "dry"
configuration or of a "wet" configuration that provides a flow of
an appropriate fluid by/through the electrode head as desired. The
various electrode heads to be described herein also may be
appropriate for other types of electrodes as well. Finally, each of
the following aspects may be used in combination with one or more
of the other aspects.
[0012] A first aspect of the present invention is generally
directed to a tissue electrode head. This electrode head includes a
fabric. At least part of this fabric is electrically conductive,
and may be electrically interconnected with an appropriate
electrical energy source. When the electrode head is disposed in an
appropriate position relative to a patient, electrical energy may
be exchanged with patient tissue via the fabric.
[0013] The fabric for the electrode head can be porous. In one
embodiment, the fabric has a porosity within a range from being
impervious to a particular fluid used with the electrode head, to
providing the fluid with an unimpeded flow. Fabric porosity may be
utilized to achieve a desired flow rate through the electrode head
(e.g., for a wet electrode configuration that will be discussed
below). Another option is to utilize a fabric porosity that
achieves a desired degree of fluid retention. The porosity of the
electrode head may also have an impact on the electrical behavior
of the electrode head. The fabric may also be characterized as
being flexible, for instance to provide a desired interface with
the patient tissue (e.g., undulating and/or curved surfaces). In
one embodiment, the fabric has a modulus of elasticity of no more
than about that of the target tissue. However, the fabric could be
incorporated as a rigid structure as well.
[0014] Generally, the construction/configuration of the fabric may
be tailored/engineered to accomplish one or more desired
objectives, for instance to provide a desired electrical field to
in turn provide a desired electrical interaction with patient
tissue. For instance, in some cases it may be desirable to provide
a substantially constant electrical conductivity along the length
of the electrode head. In other instances, it may be desirable to
provide a graded electrical conductivity along at least a portion
of the length of the electrode head in at least some respect (e.g.,
a certain length segment may be more electrically conductive than
another length segment). One or more sensors may be incorporated
into the electrode head to monitor the performance of the electrode
head in at least some respect (e.g., a thermal sensor to monitor
the electrode head/patient tissue interface temperature; a pressure
sensor to monitor the contact between the electrode head and
patient tissue; a fiber optic or ultrasound sensor for in situ
lesion identification and/or characterization).
[0015] The fabric for the electrode head may be configured in any
appropriate manner. For instance, the fabric may be in the form of
an at least generally flat or planar structure (e.g., for a ground
patch or return electrode application). The fabric may also be
formed into a hollow structure or shell having a closed distal end.
Another option would be to wrap the fabric into an at least
generally cylindrical structure. The fabric may also be in the form
of a plurality of cantilevered structures. Each of these
cantilevered structures may be of any appropriate configuration,
for instance flat or planar structures, at least generally
cylindrical structures, or the like. The electrode head also may be
configured to compress or deflect to a degree when brought into
engagement with patient tissue, or to at least substantially retain
its configuration at all times.
[0016] The entirety of the fabric may be electrically conductive or
electrically dissipative. Another option is for the fabric to
include some combination of electrically conductive materials
(e.g., electrically conductive materials being those having a
conductivity of at least about 10.sup.-2 S/m (Siemens per meter) in
one embodiment), electrically dissipative materials (e.g.,
electrically dissipative materials being those having a
conductivity of at least about 10.sup.-9 S/m in one embodiment),
and electrically non-conductive materials (e.g., electrically
non-conductive materials being those having a conductivity of less
than about 10.sup.-9 S/m in one embodiment). Any appropriate
electrically conductive material may be used by the fabric, any
appropriate electrically dissipative material may be used by the
fabric, and any appropriate electrically non-conductive material
may be used by the fabric. In one embodiment, the electrically
non-conductive material is in the form of a dielectric
material.
[0017] The fabric may be defined by a plurality of first threads or
thread segments and a plurality of second threads or thread
segments, where each first thread is electrically conductive or
dissipative, and where each second thread is electrically
non-conductive. In one embodiment, each first thread is defined by
a plurality of conductive or dissipative filaments that are wrapped
or twisted together, while each second thread is defined by a
plurality of non-conductive filaments that are wrapped or twisted
together. In any case, the various first threads and the various
second threads each may be disposed in orientations or woven
together in a manner that generates a desired electrical field for
transferring electrical energy to patient tissue and/or that
provides one or more desired properties for the electrode head. The
following characterizations may apply individually or in any
combination: 1) the plurality of first threads and the plurality of
second threads may be disposed in different orientations; 2) the
plurality of first threads may extend at least generally along a
length dimension of the tissue electrode head, or stated another
way parallel to a reference axis associated with a length dimension
of the electrode head; 3) the plurality of second threads may be
wrapped about a reference axis associated with a length dimension
of the electrode head (e.g., in combination with item number 2); 4)
at least some of the second threads may extend at least generally
along a length dimension of the tissue electrode head, or stated
another way parallel to a reference axis associated with a length
dimension of the tissue electrode head (e.g., in combination with
item number 2); and 5) each of the plurality of first threads and
each of the plurality of second threads may be wrapped about a
reference axis associated with a length dimension of the tissue
electrode head, for instance at different wrap angles.
[0018] The fabric may be defined by multiple yarns or yarn
segments, where each yarn is defined by twisting a plurality of
threads together along a length dimension of the corresponding
yarn. Generally, the features discussed herein with regard to
threads is equally applicable to yarns. In one embodiment, at least
one yarn is electrically conductive or dissipative, while at least
one yarn is electrically non-conductive. The fabric may utilize
yarns of a common stiffness, or at least one yarn used by the
fabric may have a different stiffness than at least one other yarn
used by the fabric. Furthermore, the fabric may utilize yarns
having the same denier (diameter) and thread count, or at least one
yarn used by the fabric may have a different denier (diameter)
and/or thread count compared to at least one other yarn utilized by
the fabric. The denier and/or thread count of one or more yarns of
the fabric may be utilized to control the porosity of the fabric,
which in turn may be utilized to affect a flow of fluid through the
fabric (e.g., for a "wet" electrode head configuration and as will
be discussed below), may be used to establish/affect the electrical
behavior of the electrode head, or both.
[0019] The electrode head may include a plurality of layers--any
appropriate number of layers may be utilized. Adjacent layers may
be disposed in interfacing and/or spaced relation. At least one of
these layers will include a fabric defined by one or more materials
that are electrically conductive or dissipative. In one embodiment,
first and second layers are disposed in interfacing relation, where
the first layer incorporates the fabric. The first layer may be
electrically conductive or dissipative, while the second layer may
be electrically non-conductive. One embodiment has the first layer
(electrically conductive or dissipative) being incorporated by the
electrode head so as to be positioned closer to the patient tissue
than the second layer (electrically non-conductive). Another
embodiment has the second layer (electrically non-conductive) being
incorporated by the electrode head so as to be positioned closer to
the patient tissue than the first layer (electrically conductive or
dissipative). The second layer may be formed from any appropriate
material or combination of materials, such as a dielectric.
Moreover, the second layer may be of any appropriate type, such as
a fabric or a non-fabric construction.
[0020] The fabric of the electrode head may include multiple
segments in the length dimension, and that have one or more
different properties. For instance, the fabric may include first
and second segments. The first segment may be electrically
conductive or dissipative, while the second segment may be
electrically non-conductive. One embodiment has the first segment
(electrically conductive or dissipative) being disposed distally
relative to the second segment (electrically non-conductive). The
first segment may define a distal end or distal tip of the
electrode head. Another embodiment has the second segment
(electrically non-conductive) being disposed distally relative to
the first segment (electrically conductive or dissipative). The
second segment may define a distal end or distal tip of the
electrode head.
[0021] The electrode head may include a distal end section, where
this distal end section includes a plurality of fabric segments
that are each in the form of a cantilever (e.g., a structure having
a fixed end and a free end). Each of these fabric segments may be
disposed in any appropriate orientation, including relative to each
other. In one embodiment, at least some of the fabric segments are
disposed in different orientations (e.g., in non-parallel relation
to each other). In another embodiment, a least some of the fabric
segments diverge relative to a reference axis proceeding toward
their respective fabric segment distal end (e.g., a "fanned out"
configuration). The plurality of fabric segments may collectively
define a splayed configuration for the electrode head as well.
[0022] The tissue electrode head may be of a "dry" configuration or
may be of a "wet" configuration. In the latter regard, a flow of an
appropriate fluid may be provided past and/or through the electrode
head, and which may interface with the fabric. As noted above, the
fabric may be characterized as being porous. The porosity of the
fabric may have an effect on the flow of fluid through the
electrode head. The fluid flowing through the electrode head in
turn may have an effect on the electrical and/or thermal
characteristics of the electrode head. Since the electrical and
thermal characteristics of the electrode head have an effect on a
lesion formed during RF ablation, the fabric may be
tailored/engineered to obtain a desired lesion. For instance, it
may be desirable to utilize a higher thread count at a proximal end
of the electrode head (e.g., "proximal" being in a direction of a
handle that may be associated with the tissue electrode head)
compared to a distal end of the electrode head (e.g., "distal"
being in a direction proceeding away from a handle that may be
associated with the tissue electrode head). Increasing the thread
count should decrease the porosity of the fabric.
[0023] Although any appropriate flow rate may be utilized for the
case of a wet electrode configuration, a flow rate of no more than
about 30 ml/minute may be sufficient in at least certain instances
to accomplish one or more objectives based upon the electrode head
incorporating fabric. Representative objectives include cooling the
electrode head and providing a desired degree of hydraulic
conductivity. For instance, a flow of fluid may be provided past a
conductive portion of the electrode head, and this fluid may then
carry the current to the tissue (e.g., to provide a virtual
electrode). This allows the electrode head to utilize a distal end
that is electrically non-conductive and/or for the tip of the
electrode head to be spaced from the patient tissue and still be
capable of providing an adequate electrical coupling via the fluid
flow. A substantially constant hydraulic conductivity may exist
along the length of the electrode head, or the hydraulic
conductivity may be graded along at least a portion of the length
of the electrode head (e.g., increasing progressing toward a distal
end of the electrode head). A graded hydraulic conductivity may be
achieved by modifying the porosity of the electrode head and/or
incorporating an anisotropically conductive fabric into the
electrode head.
[0024] Any appropriate way of providing a fluid flow to/through the
electrode head may be utilized. For instance and as will be
discussed in more detail below, the fabric may be wrapped around
what may be characterized as a core, plug, or mandrel. This core
may be porous to allow fluid injected therein to flow radially
outwardly through the fabric. Another option would be to include
one or more internal flow channels or the like in the core and that
terminate on an exterior surface of the core that interfaces with
the fabric. The core may be formed from any appropriate material or
combination of materials, may be electrically conductive,
electrically dissipative, or electrically non-conductive, and may
be rigid or flexible. It should be appreciated that the core may be
utilized for a dry electrode configuration as well.
[0025] A second aspect of the present invention is generally
directed to a tissue electrode head that incorporates a plurality
of electrode segments. Each of these electrode segments includes a
distal tip that is engageable with patient tissue. At least some of
these electrode segments are disposed or are disposable in
different orientations relative to each other.
[0026] The electrode head may be electrically interconnected with
any appropriate electrical energy source (e.g., an RF generator).
When the electrode head is disposed in an appropriate position
relative to a patient, electrical energy may be transferred to
patient tissue via one or more of the electrode segments. Although
each of the electrode segments may receive a common electrical
signal, such may not be required in all instances (e.g., some of
the electrode segments may not receive any electrical signal; one
or more electrode segments could receive one electrical signal,
while one or more other electrode segments could receive a
different electrical signal).
[0027] At least some of the electrode segments may be in the form
of fabric, and in one embodiment each such electrode segment is
defined entirely by or at least incorporates fabric. Therefore,
relevant portions of the discussion presented above with regard to
the first aspect may be utilized by this second aspect. However,
other materials may be utilized to define the electrode segments as
well. Although each electrode may be formed from a common material,
in one embodiment at least one of the electrode segments is formed
from one material and at least one electrode segment is formed from
a different material.
[0028] Each of the electrode segments may be in the form of a
cantilever--a structure having a fixed end and an oppositely
disposed free end (the above-noted distal tip). At least some of
the electrode segments may be characterized as diverging from each
other proceeding toward their respective electrode segment distal
tip. The plurality of electrode segments also may be characterized
as collectively defining a splayed configuration for the electrode
head.
[0029] The various electrode segments may be characterized as being
flexible or bendable. In one embodiment, each electrode segment has
a modulus of elasticity of no more than about that of the target
tissue. Although each of the electrode segments may be of a common
stiffness, one or more electrode segments may be of a different
stiffness than one or more other electrode segments. Although the
various electrode segments may be disposed in equally spaced
relation, a varying distribution of the electrode segments may be
utilized as well. Stated another way, the electrode head may
include a uniform density of electrode segments or a non-uniform
density of electrode segments.
[0030] A third aspect of the present invention is generally
directed to a tissue electrode head that incorporates a plurality
of electrode segments that are disposed in end-to-end relation, and
where at least two of these electrode sections have different
diameters.
[0031] Any appropriate number of electrode segments may be
utilized. In one embodiment, a smaller diameter electrode segment
is more distally disposed than a larger diameter electrode segment.
In another embodiment, the smallest diameter electrode segment
defines a distal end section of the electrode head, while one or
more other larger diameter electrode segments are more proximally
disposed.
[0032] The electrical conductivity may differ between two or more
of the electrode segments. One embodiment has the electrical
conductivity change from electrode segment to electrode segment.
Further in this regard, the electrical conductivity may increase on
an electrode segment-by-electrode segment basis proceeding in the
direction of the distal tip of the electrode head. Another
embodiment has the most distally disposed of the electrode segments
being of the highest electrical conductivity compared to the other
electrode segment(s).
[0033] One or more of the electrode segments may be electrically
conductive or electrically dissipative, including having each
electrode segment be electrically conductive or dissipative. One or
more of the electrode segments may be electrically non-conductive.
At least one conductive or dissipative electrode segment and at
least one non-conductive electrode segment may be utilized.
Therefore, the features discussed below in relation to the fourth
aspect may be used by this third aspect as well. Each electrode
segment may be formed from any appropriate material or combination
of materials. In one embodiment, at least one electrically
conductive or dissipative electrode segment incorporates
electrically conductive or dissipative fabric, although each of the
electrode segments could incorporate fabric. Therefore, the
features discussed above in relation to the first aspect may be
used by this third aspect as well individually or in any
combination. The features to be discussed in relation to the fifth,
sixth, and seventh aspects may be used by this third aspect as
well, individually or in any combination.
[0034] A fourth aspect of the present invention is generally
directed to a tissue electrode head that incorporates a plurality
of electrode segments that are disposed in end-to-end relation. At
least one of these electrode segments is electrically
non-conductive, while at least one of these electrode segments is
electrically conductive or electrically dissipative. At least one
of the electrode segments utilizes fabric.
[0035] Any appropriate number of electrode segments may be
utilized. In one embodiment, a non-conductive electrode segment is
more distally disposed than a conductive or dissipative electrode
segment, including where a non-conductive electrode element defines
a distal tip of the electrode head. In another embodiment, a
conductive or dissipative electrode segment is more distally
disposed than a non-conductive electrode segment, including where
this conductive or dissipative electrode element defines a distal
tip of the electrode head and includes fabric.
[0036] Each electrode segment may be formed from any appropriate
material or combination of materials. In one embodiment, at least
one electrically conductive or dissipative electrode segment
utilizes electrically conductive or dissipative fabric, although
each of the electrode segments may utilize fabric. Therefore, the
features discussed above in relation to the first aspect may be
used by this fourth aspect as well, individually or in any
combination. One or more of the electrode segments may have a
different outer diameter than at least one other electrode segment.
Therefore, the features discussed above in relation to the third
aspect may be used by this fourth aspect as well individually or in
any combination. The features to be discussed in relation to the
fifth, sixth, and seventh aspects may be used by the fourth aspect
as well, individually or in any combination.
[0037] A fifth aspect of the present invention is generally
directed to a tissue electrode head that incorporates a plurality
of electrode segments that are disposed in end-to-end relation. An
electrically non-conductive electrode segment defines a distal tip
of the electrode head, while at least one more proximally disposed
electrode segment is electrically conductive or electrically
dissipative. The various features discussed above in relation to
the first, third, and fourth aspects, as well as the sixth and
seventh aspects to be discussed below, may be used in relation to
this fifth aspect, individually or in any combination.
[0038] A sixth aspect of the present invention is generally
directed to a tissue electrode head. The electrical conductivity of
the electrode head, the hydraulic conductivity of the electrode
head, or both, is different at least at two different locations
along a length dimension of the electrode head. The various
features discussed above in relation to the first, third, fourth,
and fifth aspects, as well as the seventh aspect to be discussed
below, may be used in relation to this sixth aspect, individually
or in any combination.
[0039] A seventh aspect of the present invention is generally
directed to a tissue electrode head. The porosity of the electrode
head is different at least at two different locations along a
length dimension of the electrode head. The various features
discussed above in relation to the first, third, fourth, fifth, and
sixth aspects may be used in relation to this seventh aspect,
individually or in any combination.
[0040] The foregoing and other aspects, features, details,
utilities, and advantages of the present invention will be apparent
from reading the following description and claims, and from
reviewing the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] FIG. 1A illustrates one embodiment of a catheter electrode
system having an electrode head that incorporates an electrically
conductive/dissipative fabric.
[0042] FIG. 1B illustrates another embodiment of a catheter
electrode system having an electrode head that incorporates an
electrically conductive/dissipative fabric.
[0043] FIG. 1C illustrates one embodiment of a core about which an
electrically conductive/dissipative fabric may be wrapped for an
electrode head, and which includes a plurality of fluid
flowpaths.
[0044] FIG. 1D illustrates another embodiment of a catheter
electrode system having an electrode head that incorporates an
electrically conductive/dissipative fabric.
[0045] FIG. 1E is an enlarged view of the electrode head of FIG.
1D, along with one configuration of a base for providing a fluid to
the electrode head.
[0046] FIG. 2 is a plan view of one embodiment of a patch electrode
that utilizes an electrically conductive/dissipative fabric.
[0047] FIG. 3A illustrates a single layer of an electrically
conductive/dissipative fabric that may be used to define an
electrode head.
[0048] FIG. 3B illustrates a pair of layers that may be utilized to
define an electrode head, where at least one of these layers is an
electrically conductive/dissipative fabric.
[0049] FIG. 3C illustrates three layers that may be utilized to
define an electrode head, where at least one of these layers is an
electrically conductive/dissipative fabric.
[0050] FIG. 3D illustrates one embodiment of fabric that has been
formed into a hollow, three-dimensional shape for an electrode
head.
[0051] FIG. 3E is an end view of an electrically
conductive/dissipative fabric that has been wrapped to define an
electrode head.
[0052] FIG. 3F is an end view of multiple layers that have been
wrapped to define an electrode head, and where at least one of
these layers is an electrically conductive/dissipative fabric.
[0053] FIG. 4 is a perspective view of one embodiment of an
electrode system having an electrode head that incorporates an
electrically conductive/dissipative fabric and that also utilizes a
plurality of proximally disposed ring electrode elements.
[0054] FIG. 5 is a perspective view of one embodiment of an
electrode head that incorporates an electrically
conductive/dissipative fabric and that accommodates a fluid flow
for a wet electrode configuration.
[0055] FIG. 6A is a perspective view of one embodiment of an
electrode head that incorporates a plurality of electrically
conductive/dissipative thread/yarn segments that extend at least
generally along the length dimension of the electrode head, along
with a plurality of electrically non-conductive thread/yarn
segments that are wrapped about an axis that corresponds with a
length dimension of the electrode.
[0056] FIG. 6B is a variation of the electrode head of FIG. 6A,
where the electrode head utilizes a stepped configuration.
[0057] FIG. 7 is a perspective view of another embodiment of an
electrode head that incorporates a plurality of electrically
conductive/dissipative thread/yarn segments and electrically
non-conductive thread/yarn segments that each extend at least
generally along the length dimension of the electrode head.
[0058] FIG. 8 is a perspective view of another embodiment of an
electrode head that incorporates a plurality of electrically
conductive/dissipative thread/yarn segments and electrically
non-conductive thread/yarn segments that are each are wrapped about
an axis that corresponds with a length dimension of the electrode
head, but at different wrap angles.
[0059] FIG. 9A is a perspective view of another embodiment of an
electrode head that incorporates multiple layers that have been
wrapped to define an electrode head, and where at least one of
these layers is an electrically conductive/dissipative fabric.
[0060] FIG. 9B is a perspective view of another embodiment of an
electrode head that incorporates multiple, annular layers that
define an electrode head, and where at least one of these annular
layers is an electrically conductive/dissipative fabric.
[0061] FIG. 10 is a perspective view of another embodiment of an
electrode head that incorporates an electrically
conductive/dissipative fabric that provides a graded electrical
conductivity.
[0062] FIG. 11A is a perspective view of another embodiment of an
electrode head that incorporates an electrically non-conductive
distal tip, along with a proximally disposed section of an
electrically conductive/dissipative fabric.
[0063] FIG. 11B is a perspective view of another embodiment of an
electrode head that incorporates an electrically
conductive/dissipative tip that incorporates an electrically
conductive/dissipative fabric, along with a proximally disposed,
electrically non-conductive section.
[0064] FIG. 12A is a perspective view of another embodiment of an
electrode head that incorporates a plurality of electrode segments
that are in the form of cantilevers and that may be defined by an,
electrically conductive/dissipative fabric.
[0065] FIG. 12B is an end view of the electrode head of FIG.
12A.
[0066] FIG. 12C is an end view of the electrode head of FIG. 12A
with an alternative configuration for the electrode segments.
[0067] FIG. 13 is a perspective view of another embodiment of an
electrode head that incorporates an electrically
conductive/dissipative fabric and a plurality of sensors.
DETAILED DESCRIPTION
[0068] Various embodiments of electrodes that utilize at least one
fabric section for a corresponding electrode head will now be
described, where at least part of this fabric section is
electrically conductive or electrically dissipative. An
electrically conductive portion of a fabric section is one having
an electrical conductivity of at least about 10.sup.-2 S/m in one
embodiment. An electrically dissipative portion of a fabric section
is one having an electrical conductivity of at least about
10.sup.-9 S/m. Any such fabric section may include the following
features, individually or in any appropriate combination: 1) a
fabric section may be defined by one or more threads, where each
such thread is a collection of filaments that are twisted together
along a length dimension of the thread; 2) a fabric section may be
defined by one or more yarns, where each such yarn is a collection
of threads that are twisted together along a length dimension of
the yarn; 3) a fabric section may be defined by threads/yarns of
different diameters; 4) a fabric section may be defined by threads
having different filament counts, by yarns having different thread
counts, or both; 5) a fabric section may be formed from any
appropriate material or combination of materials; 6) a fabric
section may be of any appropriate size, shape, and/or
configuration; 7) a fabric section may be in the form of a solid
structure; 8) a fabric section may be in the form of a hollow
structure; 9) a fabric section may be in the form of an at least
substantially rigid structure; 10) a fabric section may be in the
form of a flexible structure; 11) a fabric section may have a
modulus of elasticity of no more than about that of the target
tissue (e.g., the myocardial wall) in one embodiment; 12) a fabric
section may be in the form of a porous structure; 13) a fabric
section may have a variable porosity depending on the application,
may have a porosity within a range of being impervious to a
particular fluid used with the electrode head, to providing such a
fluid with an unimpeded flow in one embodiment, or both; 14) a
fabric section may have one or more regions with different
porosities; 15) a fabric section may be used in combination with
one more other layers or sections to define an electrode head; 16)
a fabric section may be integrated with an electrode head and/or
configured to provide a desired electrical field and/or a desired
interaction with patient tissue; 17) a fabric section may
provide/accommodate a substantially constant electrical
conductivity along the length of the electrode head; 18) a fabric
section may provide/accommodate a varied electrical conductivity
along the length of the electrode head; 19) a fabric section may
provide/accommodate a substantially constant hydraulic conductivity
along the length of the electrode head; and 20) a fabric section
may provide/accommodate a varied hydraulic conductivity along the
length of the electrode head. Although these electrode heads are
particularly suited for tissue applications, where electrical
energy is exchanged between the electrode head and tissue, they may
be utilized by any appropriate electrode and for any appropriate
application.
[0069] FIG. 1A illustrates one embodiment of what may be
characterized as a tissue electrode system 10--an electrode system
that is intended to mechanically interface or at least electrically
couple with tissue. Initially, the tissue electrode system 10 may
be operatively interconnected with one or more other components,
such as a navigation display, an imaging system, an electrical
energy source, or the like. The tissue electrode system 10 is
illustrated as being in the form of a catheter electrode that may
be introduced into a patient's artery or vein at an appropriate
location (e.g., the leg, neck, or arm). Additional components may
be utilized to direct the tissue electrode system 10, more
specifically its electrode head 20, to the desired location within
the patient's body (e.g., a guidewire or introducer).
[0070] The tissue electrode system 10 includes a handle 12 (e.g.,
disposed outside of the patient's body), an elongated body 18
(e.g., a catheter or other device, and disposable within a
patient's body) that can be attached to the handle 12, and an
electrode head 20. Other components of the tissue electrode system
10 include a fluid conduit 14 and an electrical conduit 16. Each of
the fluid conduit 14 and the electrical conduit 16 may be of any
appropriate size, shape, and/or configuration. Generally, the fluid
conduit 14 provides an appropriate fluid to the electrode head 20
as desired (e.g., through a lumen or the like), while the
electrical conduit provides an appropriate electrical signal to
and/or from the electrode head 20 as desired. Incorporation of the
fluid conduit 14 by the tissue electrode system 10 provides a wet
electrode configuration. The fluid conduit 14 also may be
eliminated, providing a dry electrode configuration for the tissue
electrode system 10 (not shown).
[0071] The electrode head 20 includes at least a fabric section 22,
which may be of any appropriate size, shape, and/or configuration.
The entirety of the electrode head 20 may be defined by the fabric
section 22. Another option is for the fabric section 22 to be
disposed about and/or mounted on what may be characterized as an
internal core 24. That is, the core 24 is optional and is thereby
represented by dashed lines in FIG. 1A. In the case of the tissue
electrode system 10 of FIG. 1A, the core 24 is encased by the
fabric section 22. This need not always be the case. FIG. 1B
illustrates an alternative electrode head 20' for a tissue
electrode system 10', where its fabric section 22' does not cover a
distal end wall 27 of the core 24. Common components between the
embodiments of FIGS. 1A and 1B are identified by the same reference
numeral, and the discussion presented herein is applicable to these
components in each embodiment. Those corresponding components that
differ in at least some respect are identified by a "single prime"
designation. Various other embodiments disclosed herein utilize a
core having a distal segment that is exposed.
[0072] The core 24 may: 1) be of any appropriate size, shape,
and/or configuration; 2) be formed from any appropriate material or
combination of materials; 3) be in the form of a rigid structure or
a flexible structure; and/or 4) provide any appropriate function or
combination of functions in relation to the electrode head 20/20'.
For instance, the core 24 may provide a mounting structure for the
fabric section 22/22' (e.g., for integrating the fabric section
22/22' with the electrode head 20/20'). The core 24 may also be
utilized for directing fluid through the fabric section 22/22' for
a wet electrode application. One option would be for the core 24 to
be in the form of a solid structure that is sufficiently porous
such that a fluid flow directed into the core 24 via the fluid
conduit 14 would pass through the fabric section 22/22' at a
desired flow rate. Another option would be for the core 24 to
include one or more internal fluid conduits 28 (FIG. 1C) that
extend to an external surface of the core 24, such as its sidewall
26, distal end wall 27, or both. The intersection of a fluid
conduit 28 with the exterior of the core 24 defines a port 30. Each
port 30 may be of any appropriate size, shape, and/or
configuration. The core 24 may include any appropriate number of
ports 30, and multiple ports 30 may be disposed in any appropriate
arrangement.
[0073] FIG. 1D illustrates another variation of the tissue
electrode system 10 of FIG. 1A. Common components between the
embodiments of FIGS. 1A and 1D are identified by the same reference
numeral, and the foregoing discussion remains applicable to these
components. Those corresponding components that differ in at least
some respect are identified by a "double prime" designation. In the
case of the tissue electrode system 10'' of FIG. 1D, the electrode
head 20'' includes a fabric section 22'' that cantilevers or
extends from what may be characterized as a base 32. This base 32
is appropriately integrated with the body 18, may be of any
appropriate size, shape, and/or configuration, may be formed from
any appropriate material or combination of materials, and as shown
in FIG. 1E includes one or more fluid conduits or lumens 34 that
receive a fluid from the fluid conduit 14. Each fluid conduit 34
may be of any appropriate size, shape, and/or configuration, and
multiple fluid conduits may be disposed in any appropriate
arrangement.
[0074] The tissue electrode systems of the embodiments of FIGS. 1A,
1B, and 1D are each in the form of catheter electrodes, and each
such catheter electrode may be used to provide any appropriate
function or combination of functions (e.g., tissue ablation; tissue
mapping; return electrode). A tissue electrode system whose
electrode head incorporates a fabric section may also be used for
external tissue applications, such as in the case of the patch
electrode 40 of FIG. 2. The patch electrode 40 includes a fabric
section 42, and which may be attached to a patient's skin at any
appropriate location and in any appropriate manner (e.g., by use of
any acceptable adhesive or fastening band). An appropriate
electrical conduit 44 (e.g., a wire or cable) is electrically
interconnected with this fabric section 42. The patch electrode 40
may also be irrigated.
[0075] FIGS. 3A-F are directed to various representative
configurations of electrode heads that utilize at least one fabric
section. FIG. 3A illustrates an electrode head 50 having a single
fabric section 52 that may be of any appropriate size, shape,
and/or configuration. FIG. 3B illustrates an electrode head 54
having a pair of sections or layers 56a, 56b that are disposed in
interfacing relation and each of which may be of any appropriate
size, shape, and/or configuration. At least one of the sections
56a, 56b may be formed from a fabric that is electrically
conductive or electrically dissipative. The other of these sections
56a, 56b may also be electrically conductive (to the same extent,
to a greater extent, or to a lesser extent), may be electrically
dissipative, or may be electrically non-conductive. The other of
these sections 56a, 56b also may be in the form of a fabric, or may
be of any other appropriate form. FIG. 3C illustrates an electrode
head 58 having at least three sections or layers 60a, 60b, 60c that
are disposed in interfacing relation and each of which may be of
any appropriate size, shape, and/or configuration. At least one of
the sections 60a, 60b, 60c may be formed from a fabric that is
electrically conductive or electrically dissipative. The other of
these sections 60a, 60b, 60c may also be electrically conductive
(to the same extent, to a greater extent, or to a lesser extent),
dissipative, or non-conductive. The other of the sections 60a, 60b,
60c also may be in the form of a fabric, or may be of any other
appropriate form. Generally, any number of sections or layers may
be utilized to define an electrode head, and where at least one of
these sections or layers is fabric. Although adjacent layers may be
disposed in interfacing relation, such may not be required in all
instances. Moreover, single or multi-layer configurations may exist
in any appropriate configuration.
[0076] FIG. 3D illustrates an electrode head 62 having at least a
fabric section 64. This fabric section 64 may be a solid structure
or may be a hollow structure. The fabric section 64 may be of any
appropriate size, shape, and/or configuration. FIG. 3E illustrates
an electrode head 66 where a single fabric section or layer 68 has
been rolled up into an at least generally cylindrical
configuration. Although a space is shown between each adjacent pair
of wraps, such need not be the case. Finally, FIG. 3F illustrates
an electrode head 70 having at least two sections or layers 72a,
72b that have been rolled up into an at least generally cylindrical
configuration. Again, although a space is shown between each
adjacent pair of wraps, such need not be the case. At least one of
the layers 72a, 72b may be formed from a fabric that is
electrically conductive or electrically dissipative. The other of
these sections or layers 72a, 72b may also be electrically
conductive (to the same extent, to a greater extent, or to a lesser
extent), may be electrically dissipative, or may be electrically
non-conductive. The other of these sections or layers 72a, 72b also
may be in the form of a fabric, or may be of any other appropriate
form. Single or multi-layer configurations could also be folded
into a desired end configuration (e.g., bellows-like).
[0077] FIG. 4 illustrates a portion of another embodiment of a
tissue electrode system 80. The tissue electrode system 80 includes
an elongated body 82 that may be interconnected with an appropriate
handle (e.g., handle 12 in FIG. 1A). The body 82 is sufficiently
flexible to be directed through a bodily passageway (e.g., a vein
or artery). There are a number of ring electrode elements 84 that
are spaced along the length dimension of the body 82. An electrode
head 86 is also provided at the distal end of the body 82. This
electrode head 86 includes a fabric section 88.
[0078] FIGS. 5-13 illustrate various embodiments of electrode heads
that incorporate fabric for exchanging electrical energy with
patient tissue (e.g., transmitting electrical energy for active
electrode applications; receiving electrical energy for passive
electrode applications). Each of these electrode heads may be
utilized by any appropriate tissue electrode system, and may be
adapted as desired/required for the corresponding tissue electrode
system application. For instance, each of these electrode heads
could be utilized by any of the tissue electrode systems of FIGS.
1A, 1B, 1D, 2, and 4. Each of these electrode heads may be used
with or without a core (e.g., core 24). The fabric section of a
given electrode head may cover only a portion of the core, or may
enclose at least a portion of the core (e.g., at least generally in
accordance with the tissue electrode 10 of FIG. 1A). It will be
appreciated that any feature of any of these electrode heads may be
used by any of the other electrode heads as well, where
appropriate.
[0079] Certain components are illustrated in relation to each of
the electrode heads of FIGS. 5-13. Each is shown in conjunction
with a body 92 having an outer section 94 and an inner section 96,
and the space therebetween may be characterized as a lumen. This
body 92 has a length dimension that extends along a reference axis
98. Although the reference axis 98 is illustrated as being linear,
the body 92 will typically be flexible for being directed through a
bodily passageway and as shown in FIG. 4. An electrical conduit 100
of any appropriate type (e.g., a wire or cable) is schematically
illustrated and extends along the body 92 for electrical
interconnection with an electrically conductive/dissipative portion
of the relevant electrode head. An arrow 102 indicates a direction
of fluid flow between the inner section 96 and outer section 94 of
the body 92 (e.g., a wet electrode configuration), while
representative fluid flow arrows may be illustrated regarding the
exiting of this fluid flow through the electrode head. Any
appropriate way of providing a fluid flow to the relevant electrode
head may be utilized. Moreover, each of the electrode heads may be
utilized without any fluid flow (e.g., in a dry electrode
configuration).
[0080] The tissue electrode system 90 of FIG. 5 includes an
electrode head 104 that incorporates a fabric section 106. The
fabric section 106 again may be disposed over a core (e.g., core 24
from FIG. 1A, core 114 introduced below in relation to FIG. 6A),
may be in the form of a hollow structure, or may be in the form of
a solid structure. Various other representative electrode head
configurations that incorporate fabric for controlling/affecting
the exchange of electrical energy with tissue will now be addressed
in relation to the embodiments of FIGS. 6-13.
[0081] The tissue electrode system 110 of FIG. 6A includes an
electrode head 112. There are two main components of the electrode
head 112--a fabric section 118 and a core 114. Generally, the
fabric section 118 is disposed about the core 114 over only a
portion of its length. As such, a tip 116 of the core 114 is
exposed. This tip 116 is illustrated as having a rounded
configuration. Other configurations may be appropriate for the tip
116 as well. The discussion presented above with regard to the core
24 is equally applicable to the core 114, and will not be repeated.
In accordance with the foregoing, the fabric section 118 could also
cover the tip 116 of the core 114, and the fabric section 118 could
be used without the core 114. The length or amount of the core 114
that is exposed may be modified from that illustrated in FIG. 6A as
well. Finally, segments of exposed portions of the core 114 could
be spaced along the reference axis 98 (e.g., by having the fabric
section 118 be wrapped about the core 114 at a plurality of
locations that are spaced along the reference axis 98). Each of
these permutations is applicable to the various embodiments
disclosed herein, with the exception of the FIG. 12A
embodiment.
[0082] The fabric section 118 used by the electrode head 112
includes what may be characterized as a plurality of first yarn or
thread segments 120 that are electrically conductive or
electrically dissipative, as well as what may be characterized as a
plurality of the second yarn or thread segments 122 that are
electrically non-conductive. Generally, the various first yarn
segments 120 are disposed in one orientation, while the various
non-conductive second yarn segments 122 are disposed in a different
orientation. Further in this regard and for the illustrated
embodiment, the first yarn segments 120 extend at least generally
linearly or axially along the length dimension of the electrode
head 112 (e.g., at least generally parallel with the reference axis
98, or so as to define the warp of the fabric section 118), while
the non-conductive second yarn segments 122 are disposed or wrapped
about the reference axis 98 and thereby cross or intersect with the
first yarn segments 120 (e.g., so as to define the weft of the
fabric section 118). The various first yarn segments 120 and the
various second yarn segments 122 are woven together to define the
fabric section 118 (e.g., illustrated by the squiggly lines
defining the first yarn segments 120).
[0083] The tissue electrode system 130 of FIG. 6B is illustrated as
a variation of the tissue electrode system 110 of FIG. 6A, although
the stepped configuration of its electrode head 132 may be used by
any of the tissue electrode systems disclosed herein with the
exception of the FIG. 12A embodiment. There are two main components
of the electrode head 132--a fabric section 138 and a core 114. The
fabric section 138 used by the electrode head 132 includes what may
be characterized as a plurality of first yarn or thread segments
140 that are electrically conductive or electrically dissipative
(e.g., in accordance with the first yarn segments 120 discussed
above in relation to FIG. 6A), as well as what may be characterized
as a plurality of the second yarn or thread segments 142 that are
electrically non-conductive (e.g., in accordance with the second
yarn segments 122 discussed above in relation to FIG. 6A).
[0084] There are two discrete portions of the fabric section 138
and which may be characterized as electrode segments 144a and 144b
that are disposed in end-to-end relation. Each of the electrode
segments 144a, 144b includes the noted first yarn segments 140 and
the second yarn segments 142. Generally, the outer diameter of the
electrode segment 144a is different than the outer diameter of the
electrode segment 144b. In the illustrated embodiment, the outer
diameter of the electrode segment 144a (the distally disposed
portion of the fabric section 138) is smaller than the outer
diameter of the electrode segment 144b (the proximally disposed
portion of the fabric section 138).
[0085] The tissue electrode system 150 of FIG. 7 includes an
electrode head 152 that in turn incorporates a fabric section 158.
Instead of being wrapped around a core 114, the fabric section 158
is wrapped around itself or wrapped into a desired configuration
(cylindrical in the illustrated embodiment, and as indicated by the
spiral on the exposed, distal end of the electrode head 152). The
fabric section 158 used by the electrode head 152 includes what may
be characterized as a plurality of first yarn or thread segments
160 that are electrically conductive or electrically dissipative,
as well as what may be characterized as a plurality of the second
yarn or thread segments 162 that are electrically non-conductive.
Generally, the various first yarn segments 160 are disposed in a
common orientation with at least some of the non-conductive second
yarn segments 162 (e.g., disposed in at least generally parallel
relation). In this regard, the first yarn segments 160 and some of
the non-conductive second yarn segments 162 extend at least
generally linearly or axially along the length dimension of the
electrode head 152 (e.g., at least generally parallel with the
reference axis 98, or so as to define the warp of the fabric
section 158). Furthermore, some of the non-conductive second yarn
segments 162 are disposed or wrapped about the reference axis 98
and thereby cross or intersect with the first yarn segments 160 and
those second yarn segments 162 that are similarly oriented (e.g.,
so as to define the weft of the fabric section 158). The various
first yarn segments 160 and the various second yarn segments 162
are woven together to define the fabric section 158 (e.g.,
illustrated by the squiggly lines defining the first yarn segments
160). Although a pair of non-conductive second yarn segments 162 is
illustrated as being disposed between adjacent pairs of first yarn
segments 160, the commonly oriented first yarn segments 160 and
non-conductive second yarn segments 162 may be arranged in any
appropriate pattern, for instance to achieve a desired electrical
field (e.g. the similarly oriented first yarn segments 160 and
second non-conductive yarn segments 162 could be disposed in
alternating relation).
[0086] The tissue electrode system 170 of FIG. 8 includes an
electrode head 172. There are two main components of the electrode
head 172--a fabric section 178 and a core 114. The fabric section
178 used by the electrode head 172 includes what may be
characterized as a plurality of first yarn or thread segments 180
that are electrically conductive or electrically dissipative, as
well as what may be characterized as a plurality of the second yarn
or thread segments 182 that are electrically non-conductive.
Generally, the various first yarn segments 180 are disposed in one
orientation, while the various non-conductive second yarn segments
182 are disposed in a different orientation. In this regard, the
first yarn segments 180 are disposed or wrapped about the reference
axis 98 at one angle. Furthermore, the non-conductive second yarn
segments 182 are disposed or wrapped about the reference axis 98 at
a different angle than the first yarn segments 180, but still cross
or intersect with the first yarn segments 180. The fabric section
178 illustrates that a first set of non-conductive second yarn
segments 182 are wrapped about the reference axis 98 at one angle
and that a second set of non-conductive second yarn segments 182
are wrapped about the reference axis 98 at an opposite angle. This
may not be required in all instances. In any case, the various
first yarn segments 180 and the various second yarn segments 122
are woven together to define the fabric section 178 (e.g.,
illustrated by the squiggly lines defining the first yarn segments
180).
[0087] The tissue electrode system 190 of FIG. 9A includes an
electrode head 192 that in turn incorporates an electrically
conductive or electrically dissipative fabric section or layer 198
and an electrically non-conductive section or layer 204. The fabric
section 198 and non-conductive section 204 are disposed in
interfacing relation and wrapped together into a desired
configuration (at least generally cylindrical in the illustrated
embodiment), with the fabric section 198 defining an exterior
sidewall surface for the electrode head 192. Stated another way,
the radially outermost portion of the fabric section 198 is
disposed radially outwardly from the radially outermost portion of
the non-conductive section 204, where a distance in the radial
dimension is measured from the reference axis 98. Although the
non-conductive section 204 may be in the form of a fabric, the
non-conductive section 204 may be formed from any appropriate type
of non-conductive material or combination of materials, and may be
of any appropriate form or construction.
[0088] The tissue electrode system 210 of FIG. 9B includes an
electrode head 212 that in turn incorporates a plurality of
concentrically disposed annular sections or layers 214a-e. Adjacent
pairs of the annular sections 214a-e are disposed in interfacing
relation in the illustrated embodiment, although a standoff could
be disposed between at least one of the adjacent pairs of the
annular sections 214a-e at one or more locations along the
reference axis 98. At least one of the annular sections 214a-e is
in the form of an electrically conductive or electrically
dissipative fabric. Any number of the annular sections 214a-e could
be in the form of an electrically conductive or electrically
dissipative fabric. One or more of the annular sections 214a-e
could also be in the form of an electrically non-conductive
material (e.g., fabric). Any arrangement of electrically
conductive/dissipative fabric and electrically non-conductive
materials could be used for the various annular sections
214a-e.
[0089] The tissue electrode system 220 of FIG. 10 includes an
electrode head 222. There are two main components of the electrode
head 222--a fabric section 224 and a core 114. Generally, the
electrical conductivity of the fabric section 224, the hydraulic
conductivity of the fabric section 224, or both, is graded or
changes proceeding along the reference axis 98. In one embodiment,
the electrical conductivity of the fabric section 224 decreases
proceeding in the direction of the arrow A (and graphically
depicted by the density of the shading provided for the fabric
section 224). This variation of the electrical conductivity of the
fabric section 224 may be realized in any appropriate manner. For
instance, the porosity of the fabric section 224 may change
proceeding along the reference axis 98. Threads of different
filament count, yarns of different thread count, or both may be
used to define the fabric section 224 and achieve the conductivity
gradient as well. Similarly, the noted variation of the hydraulic
conductivity of the fabric section 224 may be realized in any
appropriate manner as well. A graded hydraulic conductivity may be
achieved by modifying the porosity of the electrode head 222 and/or
incorporating an anisotropically conductive fabric into the
electrode head 222.
[0090] The tissue electrode system 230 of FIG. 11A includes an
electrode head 232. There are two main components of the electrode
head 232--an electrically conductive or electrically dissipative
fabric section or electrode segment 238 and an electrically
non-conductive section or electrode segment 242 that are disposed
in end-to-end relation. Although the non-conductive section 242 may
be in the form of a fabric, the non-conductive section 242 may be
formed from any appropriate type of non-conductive material or
combination of materials, and may be of any appropriate form or
construction. In any case, the non-conductive section 242 is
distally disposed in relation to the fabric section 238. In the
illustrated embodiment, a distal end 244 of the electrode head 232
is defined by the non-conductive section 242. Stated another way,
the non-conductive section 242 defines a distal tip of the
electrode head 232 in the illustrated embodiment. Although the
non-conductive section 242 could be in the form of a solid
structure to define a solid distal end 244, the non-conductive
section 242 could be defined by a wrapped configuration at least
generally in accordance with the foregoing (e.g., to provide a
distal end 244 have the type of configuration illustrated in FIG.
7).
[0091] The distally disposed non-conductive section 242 provides a
standoff between the target tissue and the fabric section 238 in
the case of the electrode head 232 of FIG. 11A. A conductive fluid
may be directed to the electrode head 232 as noted above (e.g.,
through a flow path between the outer section 94 and inner section
96 of the body 92, and at least generally in the direction
indicated by the arrow 102). This conductive fluid may carry a
current from the fabric section 238 of the electrode head 232 to
the target tissue, thereby creating the effect of a virtual
electrode.
[0092] The tissue electrode system 250 of FIG. 11B includes an
electrode head 252. There are two main components of the electrode
head 252--an electrically conductive or dissipative fabric section
or electrode segment 258 and an electrically non-conductive section
or electrode segment 262 that are disposed an end-to-end relation.
Although the non-conductive section 262 may be in the form of a
fabric, the non-conductive section 262 may be formed from any
appropriate type of non-conductive material or combination of
materials, and may be of any appropriate form or construction. In
any case, the fabric section 258 is distally disposed in relation
to the non-conductive section 262. In the illustrated embodiment, a
distal end 264 of the electrode head 252 is defined by the fabric
section 258, and is only schematically illustrated in FIG. 11B.
This distal end 264 could be at least generally in accordance with
the distal end shown in FIG. 7, or could be in the form of an
appropriately shaped distal end of a core with the fabric section
258 being disposed thereabout. It should be appreciated that the
fabric section 258 may also be characterized as defining a distal
tip of the electrode head 232 in the illustrated embodiment.
[0093] The tissue electrode system 270 of FIGS. 12A-B includes an
electrode head 272. There are two main components of the electrode
head 272--a base 280 and a plurality of electrode segments 278 that
extend from the base 280. Generally, the electrode segments 278 are
each in the form of a cantilever, having a fixed end (e.g., at the
base 280) and a distally-disposed free end. At least some of the
electrode segments 278 are disposed in different orientations. This
is subject to a number of characterizations. One is that at least
some of the electrode segments 278 are disposed in non-parallel
relation. Another is that at least some of the electrode segments
diverge relative to the reference axis 98 proceeding from the base
280 toward their respective distal end. Another is that the
plurality of electrode segments 278 collectively define a splayed
configuration.
[0094] Although the electrode segments 278 could be formed from any
appropriate material, in one embodiment each of the electrode
segments 278 includes or are defined by an electrically conductive
or electrically dissipative fabric. The electrode segments 278 may
be of any appropriate size, shape, and/or configuration. For
instance, each electrode segment 278 could be in the form of a
single thread segment or a single yarn segment, for instance in
accordance with FIGS. 12A-B. Another option would be for each of
the fabric sections 278 to be in the form of a fabric section, such
as the fabric sections 278a illustrated in FIG. 12C.
[0095] The various electrode segments 278 may be disposed in any
appropriate arrangement. Each of the various electrode segments 278
may be equally spaced from each other. Two or more different
spacings between adjacent electrode segments 278 may be utilized as
well. In one embodiment, the electrode head 292 utilizes an at
least substantially constant density for the various electrode
segments 278. Another embodiment utilizes a varied density for the
various electrode segments 278.
[0096] The tissue electrode system 290 of FIG. 13 includes an
electrode head 292, that in turn includes an electrically
conductive or electrically dissipative fabric section 298. The
electrode head 292 further includes one or more sensors 300. Three
sensors 300 are illustrated in relation to the electrode head 292,
although any number of sensors 300 may be utilized and may be
disposed at any appropriate location. Each sensor 300 may be of any
appropriate size, shape, configuration, and/or type, and
furthermore may provide any appropriate function or combination of
functions. For instance, a sensor 300 may be provided to monitor
temperature (e.g., an electrode head-tissue interface temperature),
a sensor 300 may be provided to monitor pressure (e.g., a pressure
being exerted by the electrode head 292 on the tissue), or a sensor
300 may be used for situ lesion identification and characterization
(e.g., using fiber optics, ultrasound, or both). One or more of
these sensors 300 may be utilized by any of the electrode heads
disclosed herein.
[0097] The electrode heads described herein may be used with any
appropriate type of electrode. For instance, each of these
electrode heads may be integrated with a catheter electrode.
Another option is for each of these electrode heads to be used by a
ground patch or the like that interfaces with the patient's skin
(e.g., interfaces with an exterior surface of the patient). Each
such electrode head may also provide any appropriate function or
combination of functions. One embodiment has the electrode head
providing an active function, such as tissue ablation or tissue
mapping. Another embodiment has the electrode head configured for a
passive function, such as for use by a return electrode. Each
electrode head may direct electrical energy to a single location
(e.g., for spot tissue ablation), or may apply electrical energy to
tissue while being moved relative to the tissue (e.g., to create a
linear lesion).
[0098] Each of the electrode heads disclosed herein may be used in
a dry electrode configuration, or alternatively in a wet electrode
configuration. With regard to a wet electrode configuration, any
appropriate fluid may be utilized. In one embodiment, the fluid is
electrically conductive. Representative fluids for a wet electrode
configuration include without limitation saline, radioopaque
solutions, and liquid drugs. Any appropriate flow rate may be
provided to any of the electrode heads disclosed herein as well. In
one embodiment, a flow rate of no more than about 30 ml/minute may
be provided to any of the electrode heads disclosed herein, and
which may be suitable based upon the use of one or more fabric
sections.
[0099] Although various embodiments of this invention have been
described above with a certain degree of particularity, those
skilled in the art could make numerous alterations to the disclosed
embodiments without departing from the spirit or scope of this
invention. All directional references (e.g., upper, lower, upward,
downward, left, right, leftward, rightward, top, bottom, above,
below, vertical, horizontal, clockwise, and counterclockwise) are
only used for identification purposes to aid the reader's
understanding of the present invention, and do not create
limitations, particularly as to the position, orientation, or use
of the invention. Joinder references (e.g., attached, coupled,
connected, and the like) are to be construed broadly and may
include intermediate members between a connection of elements and
relative movement between elements. As such, joinder references do
not necessarily infer that two elements are directly connected and
in fixed relation to each other unless otherwise noted. It is
intended that all matter contained in the above description or
shown in the accompanying drawings shall be interpreted as
illustrative only and not limiting. Changes in detail or structure
may be made without departing from the spirit of the invention as
defined in the appended claims.
* * * * *