U.S. patent application number 10/280653 was filed with the patent office on 2004-04-29 for ablation catheters.
This patent application is currently assigned to The Regents of the University of Michigan. Invention is credited to Morady, Fred, Oral, Hakan.
Application Number | 20040082947 10/280653 |
Document ID | / |
Family ID | 32106987 |
Filed Date | 2004-04-29 |
United States Patent
Application |
20040082947 |
Kind Code |
A1 |
Oral, Hakan ; et
al. |
April 29, 2004 |
Ablation catheters
Abstract
The present invention relates generally to multifunctional
catheters for performing ablation procedures, and more particularly
to ablation catheters utilized in the treatment of atrial
fibrillation and other cardiac disorders. The present invention
eliminates many of the problems associated with previous ablation
catheters by providing an ablation treatment not dependent upon
continuous lesions.
Inventors: |
Oral, Hakan; (Ann Arbor,
MI) ; Morady, Fred; (Ann Arbor, MI) |
Correspondence
Address: |
MEDLEN & CARROLL, LLP
Suite 350
101 Howard Street
San Francisco
CA
94105
US
|
Assignee: |
The Regents of the University of
Michigan
Ann Arbor
MI
|
Family ID: |
32106987 |
Appl. No.: |
10/280653 |
Filed: |
October 25, 2002 |
Current U.S.
Class: |
606/41 ;
606/47 |
Current CPC
Class: |
A61B 2018/00214
20130101; A61B 2018/1435 20130101; A61B 18/1492 20130101 |
Class at
Publication: |
606/041 ;
606/047 |
International
Class: |
A61B 018/18 |
Claims
We claim:
1. A device comprising: i) an elongate catheter body, wherein said
elongate catheter body comprises a proximal end and a distal end,
and ii) a spiral tip; wherein said spiral tip is configured for
tissue ablation; said spiral tip is mounted at said distal end of
said elongate catheter body; said spiral tip is capable of
expansion and contraction.
2. The device of claim 1, wherein said device comprises conductive
coils on said spiral tip.
3. The device of claim 2, wherein said conductive coils comprise at
least one conductive coil measuring 2-20 millimeters in size.
4. The device of claim 1, wherein said device comprise conductive
plates on said spiral tip.
5. The device of claim 4, wherein said distribution comprises at
least one conductive plate measuring 2-20 millimeters in size.
6. The device of claim 1, wherein said spiral tip is positioned
perpendicularly to said distal end of said elongate catheter
body.
7. The device of claim 1, wherein said spiral tip comprises a
plurality of loops.
8. The device of claim 7, wherein said plurality of loops comprises
at least one complete loop.
9. The device of claim 7, wherein said loops are separated by
gaps.
10. The device of claim 9, wherein said gaps measure less than 5
millimeters.
11. The device of claim 1, wherein said spiral tip is peripherally
mounted at said distal end of said elongate catheter body.
12. The device of claim 1, wherein said spiral tip is configured to
create spiral lesions in body tissue.
13. The device of claim 1, further comprising iii) a handle,
wherein said handle is attached to proximal end of said elongate
catheter body.
14. The device of claim 13, wherein said handle is configured to
control expansion and contraction of said spiral tip.
15. The device of claim 1, wherein said device further comprises an
energy source configured to permit emission of energy from said
spiral tip.
16. A device comprising: i) an elongate catheter body, wherein said
elongate catheter body comprises a proximal end and a distal end,
and ii) an umbrella tip body; said umbrella tip body comprises a
central post, and a plurality outer arms; wherein said umbrella tip
body is configured for tissue ablation; wherein said umbrella tip
body is mounted at said distal end of said elongate catheter
body.
17. The device of claim 16, wherein said central post extends from
distal end of said elongate catheter body.
18. The device of claim 16, wherein said plurality of outer arms
attach at distal and proximal ends of said central post.
19. The device of claim 16, wherein said device comprises
conductive coils on said plurality of outer arms.
20. The device of claim 19, wherein said conductive coils comprise
at least at least one conductive coil measuring 4-10 millimeters in
size.
21. The device of claim 16, wherein said device comprises
conductive plates on said plurality of outer arms.
22. The device of claim 21, wherein said conductive plates comprise
at least one conductive plate measuring 2-20 millimeters in
size.
23. The device of claim 16, wherein said umbrella tip is configured
to create radial lesions in body tissue.
24. The device of claim 16, further comprising iii) a handle;
wherein said handle is attached to proximal end of said elongate
catheter body.
25. The device of claim 24, wherein said handle is configured to
control expansion and contraction of said umbrella tip body.
26. The device of claim 16, wherein said device further comprises
an energy source configured to permit emission of energy from said
umbrella tip body.
27. A method of treating body tissue comprising the steps of: a)
providing a device comprising: i) an elongate catheter body,
wherein said elongate catheter body comprises a proximal end and a
distal end; and ii) a spiral tip, wherein said spiral tip is
configured for tissue ablation; said spiral tip is mounted at said
distal end of said elongate catheter body; said spiral tip is
capable of expansion and contraction; and b) inserting the catheter
through a major blood vessel; and c) guiding the catheter to a
target location; and d) positioning the spiral tip with said target
location; and e) releasing energy from said spiral tip into said
target location.
28. The method of claim 27, wherein said energy is radio-frequency
energy.
29. The method of claim 27, wherein said major blood vessel is
selected from the group comprising jugular vein, femoral vein,
femoral artery.
30. The method of claim 27, wherein said target location is a
location within a mammalian organism.
31. The method of claim 27, wherein said target location is a
mammalian organ.
32. The method of claim 27, wherein said target location is a
tumor.
33. The method of claim 27, wherein said method is used to treat
atrial fibrillation.
34. The method of claim 33, wherein said target location is an
atrium of the heart.
35. The method of claim 27, wherein said method is used to treat
cardiac arrhythmias.
36. The method of claim 35, wherein said target location is a
heart.
37. A method of treating body tissue comprising the steps of: a)
providing a device comprising: i) an elongate catheter body,
wherein said elongate catheter body comprises a proximal end and a
distal end; and ii) an umbrella tip; said umbrella tip comprises a
central post, and a plurality of outer arms; said umbrella tip is
configured for tissue ablation; said umbrella tip is mounted at
said distal end of said elongate catheter body; and b) inserting
the catheter through a major blood vessel; and c) guiding the
catheter to a target location; and d) positioning the umbrella tip
with said target location; and e) releasing energy from said
umbrella tip into said target location.
38. The method of claim 37, wherein said energy is radio-frequency
energy.
39. The method of claim 37, wherein said major blood vessel is
selected from the group comprising jugular vein, femoral vein,
femoral artery.
40. The method of claim 37, wherein said target location is a
location within a mammalian organism.
41. The method of claim 37, wherein said target location is a
mammalian organ.
42. The method of claim 37, wherein said target location is a
tumor.
43. The method of claim 37, wherein said method is used to treat
atrial fibrillation.
44. The method of claim 43, wherein said target location is an
atrium of the heart.
45. The method of claim 37, wherein said method is used to treat
cardiac arrhythmias.
46. The method of claim 45, wherein said target location is a
heart.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to catheters for
performing targeted tissue ablation in a subject. In particular,
the present invention provides devices comprising wire tipped and
umbrella tipped ablation catheters, and methods for treating
conditions (e.g., cardiac arrhythmias) with these devices.
BACKGROUND OF THE INVENTION
[0002] Mammalian organ function typically occurs through the
transmission of electrical impulses from one tissue to another. A
disturbance of such electrical transmission may lead to organ
malfunction. One particular area where electrical impulse
transmission is critical for proper organ function is in the heart.
Normal sinus rhythm of the heart begins with the sinus node
generating an electrical impulse that is propagated uniformly
across the right and left atria to the atrioventricular node. The
atrioventricular node in return causes the atria to contract.
Atrial contraction leads to the pumping of blood into the
ventricles in a manner synchronous with the pulse.
[0003] Atrial fibrillation refers to a type of cardiac arrhythmia
where there is disorganized electrical conduction in the atria
causing rapid uncoordinated contractions which result in
ineffective pumping of blood into the ventricle and a lack of
synchrony. During atrial fibrillation, the atrioventricular node
receives electrical impulses from numerous locations throughout the
atria instead of only from the sinus node. This overwhelms the
atrioventricular node into producing an irregular and rapid
heartbeat. As a result, blood pools in the atria that increases a
risk for blood clot formation. The major risk factors for atrial
fibrillation include age, coronary artery disease, rheumatic heart
disease, hypertension, diabetes, and thyrotoxicosis. Atrial
fibrillation affects 7% of the population over age 65.
[0004] Atrial fibrillation treatment options are limited. Lifestyle
change only assists individuals with lifestyle related atrial
fibrillation. Medication therapy assists only in the management of
atrial fibrillation symptoms, may present side effects more
dangerous than atrial fibrillation, and fail to cure atrial
fibrillation. Electrical cardioversion attempts to restore sinus
rhythm but has a high recurrence rate. In addition, if there is a
blood clot in the atria, cardioversion may cause the clot to leave
the heart and travel to the brain or to some other part of the
body, which may lead to stroke. What are needed are new methods for
treating atrial fibrillation and other conditions involving
disorganized electrical conduction.
SUMMARY OF THE INVENTION
[0005] The present invention relates generally to catheters for
performing targeted tissue ablation in a subject. In particular,
the present invention provides devices comprising wire tipped and
umbrella tipped ablation catheters, and methods for treating
conditions (e.g., cardiac arrhythmias) with these devices.
[0006] In some embodiments, the present invention provides a device
(e.g., for performing at least one function at an internal site in
a subject), comprising an elongate catheter body. The elongate
catheter body may comprise a proximal end, a distal end, and a
spiral tip, wherein the spiral tip is configured for tissue
ablation. In addition, the spiral tip may be mounted at the distal
end of the elongate catheter body. The spiral tip may be capable of
expansion and contraction. In further embodiments, the spiral tip
may be mounted either centrally or peripherally with the elongate
catheter body. In preferred spiral top embodiments, the spiral tip
will be configured to create spiral lesions in targeted body
tissue.
[0007] In other embodiments, the device may comprise conductive
coils on the spiral tip. In particular embodiments, the conductive
coils may comprise at least one conductive coil measuring 2-20
millimeters in size. Alternatively, in some embodiments the device
may comprise conductive plates on the spiral tip. In particular
embodiments, at least one such conductive plate may measure 2-20
millimeters in size.
[0008] Embodiments with a spiral tip may have the spiral tip
positioned perpendicularly to the distal end of the elongate
catheter body. In addition, in some embodiments, the spiral tip may
comprise a plurality of loops. In further embodiments the spiral
tip may have at least one complete loop. In other embodiments, the
spiral tip loops may be separated by gaps. In particular
embodiments, such gaps may measure less than 10 millimeters.
[0009] Some embodiments may also comprise a handle attached to the
proximal end of the elongate catheter body. In further embodiments,
the handle may be configured to control expansion or contraction of
the spiral tip as well as flexion and extension of the catheter
tip. In yet other embodiments, the device will further comprise an
energy source configured to permit emission of energy from the
spiral tip.
[0010] In some embodiments, the present invention provides an
elongate catheter body, wherein the elongate catheter body
comprises a proximal and distal ends, and an umbrella tip body. In
some embodiments, the umbrella tip body may comprise a central
post, and a plurality outer arms. In preferred embodiments, the
umbrella tip body is configured for tissue ablation. In other
embodiments, the umbrella tip body may be mounted at the distal end
of the elongate catheter body.
[0011] In some embodiments, the present invention provides a
central post extending from distal end of said elongate catheter
body. In other embodiments, the plurality of outer arms may attach
at distal and proximal ends of the central post.
[0012] In other embodiments, the device may comprise conductive
coils on the outer arms. In particular embodiments, the conductive
coils may comprise at least one conductive coil measuring 2-20
millimeters in size. In other embodiments, the conductive coils may
comprise at least one conductive coil measuring 4-8 millimeters in
size. Alternatively, in some embodiments the device may comprise
conductive plates on the outer arms. In particular embodiments, at
least one such conductive plate may measure 2-20 millimeters in
size. In other embodiments, the conductive plates may comprise at
least one conductive plate measuring 4-8 millimeters in size. In
preferred embodiments, the umbrella tip may be configured to create
radial lesions in body tissue.
[0013] Some embodiments may also comprise a handle attached to the
proximal end of the elongate catheter body. In further embodiments,
the handle may be configured to control expansion or contraction of
the umbrella tip body as well as flexion and extension of the
catheter tip. In yet other embodiments, the device will further
comprise an energy source configured to permit emission of energy
from the umbrella tip body.
[0014] In some embodiments, the present invention provides a method
of treating body tissues. In such embodiments, the method comprises
the steps of providing a device, and detailed treatment steps. In
other embodiments, the present invention provides a radio-frequency
energy source.
[0015] In particular embodiments, the device may comprise an
elongate catheter body, wherein the elongate catheter body
comprises a proximal end and a distal end, and also a spiral tip,
wherein the spiral tip may be configured for tissue ablation, the
spiral tip mounted at the distal end of the elongate catheter body,
and is capable of expansion and contraction.
[0016] In other particular embodiments, the device may comprise an
elongate catheter body, wherein the elongate catheter body
comprises a proximal end and a distal end, and also an umbrella tip
body, wherein the umbrella tip body may be configured for tissue
ablation, the umbrella tip body is mounted at the distal end of the
elongate catheter body, and the umbrella tip body is capable of
expansion and contraction. In still further embodiments, the
umbrella tip may comprise a central post, and a plurality of outer
arms.
[0017] In some embodiments, the detailed treatment steps may
comprise the inserting of the catheter through a major vein or
artery, the guiding of the catheter to the selected body tissue
site by appropriate manipulation through the vein or artery, the
guiding of the catheter to the selected body tissue site, the
positioning of the device with the selected body tissue; and the
releasing of energy from the device into the body tissue.
[0018] In particular embodiments, the detailed treatment steps may
be specific for treating atrial fibrillation, and comprise the
inserting of the catheter through a major vein or artery, the
guiding of the catheter into the atria of the heart by appropriate
manipulation through the vein or artery, the guiding of the
catheter to the target atrial region, the positioning the device
with the targeted atrial region; and a releasing of energy from the
device into the targeted atrial region.
[0019] In still further embodiments, the detailed treatment steps
may be specific for treating cardiac arrhythmias, and comprise the
inserting of the catheter through a major vein or artery, the
guiding of the catheter into the heart by appropriate manipulation
through the vein or artery, the guiding of the catheter to the
targeted heart region, the positioning of the device with the
targeted heart region; and the releasing of energy from the device
into the targeted heart region.
DESCRIPTION OF THE FIGURES
[0020] FIG. 1 shows one wire tip ablation catheter embodiment.
[0021] FIG. 2 shows one embodiment of the wire tip ablation
catheter.
[0022] FIG. 3 shows one embodiment of the wire tip ablation
catheter utilizing conductive plates.
[0023] FIG. 4 shows one embodiment of the wire tip ablation
catheter utilizing conductive coils.
[0024] FIG. 5 shows one embodiment of the umbrella tip ablation
catheter.
[0025] FIG. 6 shows one embodiment of the umbrella tip ablation
catheter.
[0026] FIG. 7 shows one embodiment of the umbrella tip ablation
catheter.
[0027] FIG. 8 shows one embodiment of the umbrella tip ablation
catheter.
[0028] FIG. 9 shows one embodiment of the umbrella tip ablation
catheter.
[0029] FIG. 10 shows one embodiment of the umbrella tip ablation
catheter.
[0030] FIG. 11 shows one embodiment of the umbrella tip ablation
catheter.
GENERAL DESCRIPTION OF THE INVENTION
[0031] The present invention provides catheters for performing
targeted tissue ablation in a subject. In particular, the present
invention provides devices comprising wire tipped and umbrella
tipped catheter ablation devices, and methods for treating
conditions (e.g., super ventricular tachycardia with these
devices.
[0032] As described above, the normal functioning of the heart
relies on proper electrical impulse generation and transmission. In
certain heart diseases (e.g., atrial fibrillation) proper
electrical generation and transmission are disrupted. In order to
restore proper electrical impulse generation and transmission, the
catheters of the present invention may be employed.
[0033] In general, catheter ablation therapy provides a method of
treating cardiac arrhythmias. Physicians make use of catheters to
gain access into interior regions of the body. Catheters with
attached ablating devices are used to destroy targeted tissue. In
the treatment of cardiac arrhythmias, a specific area of cardiac
tissue emitting or conducting erratic electrical impulses is
initially localized. A user (e.g., a physician) will direct a
catheter through a main vein or artery into the interior region of
the heart that is to be treated. The ablating element is next
placed near the targeted cardiac tissue that is to be ablated. The
physician directs an energy source from the ablating element to
ablate the tissue and form a lesion. In general, the goal of
catheter ablation therapy is to destroy cardiac tissue suspected of
emitting erratic electric impulses, thereby curing the heart of the
disorder. For treatment of atrial fibrillation currently available
methods have shown only limited success and/or employ devices that
are not practical.
[0034] The ablation catheters of the present invention allow the
generation of lesions of appropriate size and shape to treat
conditions involving disorganized electrical conduction (e.g.,
atrial fibrillation). The ablation catheters of the present
invention are also practical in terms of ease-of-use and risk to
the patient. In general, no catheter technique has been shown to
have a high efficacy in treatment of persistent atrial
fibrillation. Catheters that generate linear or curvilinear lesions
in the left or right atrial tissue have a very limited efficacy.
Moreover, the procedure length and the incidence of complications
are significantly high with current approaches. Another approach
utilizes encircling of the left atrial tissue by point-by-point
applications. An additional approach utilizes encircling of the
left atrial tissue by point-by-point applications of
radio-frequency energy. However, to generate complete circles this
approach is time consuming and has limited efficacy. The present
invention addresses this need with, for example, wire tip and
umbrella ablation catheters and methods of using these ablation
catheters to create spiral or radial lesions in the endocardial
surface of the atria by delivery of energy (e.g., radio-frequency).
The lesions created by the wire tipped and umbrella tipped ablation
catheters are suitable for inhibiting the propagation of
inappropriate electrical impulses in the heart for prevention of
reentrant arrhythmias.
[0035] Definitions
[0036] To facilitate an understanding of the invention, a number of
terms are defined below.
[0037] As used herein, the terms "subject" and "patient" refer to
any animal, such as a mammal like livestock, pets, and preferably a
human. Specific examples of "subjects" and "patients" include, but
are not limited, to individuals requiring medical assistance, and
in particular, requiring atrial fibrillation catheter ablation
treatment.
[0038] As used herein, the terms "catheter ablation" or "ablation
procedures" or "ablation therapy," and like terms, refer to what is
generally known as tissue destruction procedures. Ablation is often
used in treating several medical conditions, including abnormal
heart rhythms. It can be performed both surgically and
non-surgically. Non-surgical ablation is typically performed in a
special lab called the electrophysiology (EP) laboratory. During
this non-surgical procedure a catheter is inserted into the heart
and then a special machine is used to direct energy to the heart
muscle. This energy either "disconnects" or "isolates" the pathway
of the abnormal rhythm (depending on the type of ablation). It can
also be used to disconnect the electrical pathway between the upper
chambers (atria) and the lower chambers (ventricles) of the heart.
For individuals requiring heart surgery, ablation can be performed
during coronary artery bypass or valve surgery.
[0039] As used herein, the term "wire tip body" refers to the
distal most portion of a wire tip catheter ablation instrument. A
wire tip body is not limited to any particular size. A wire tip
body may be configured for energy emission during an ablation
procedure.
[0040] As used herein, the term "spiral tip" refers to a wire tip
body configured into the shape of a spiral. The spiral tip is not
limited in the number of spirals it may contain. Examples include,
but are not limited to, a wire tip body with one spiral, two
spirals, ten spirals, and a half of a spiral.
[0041] As used herein the term "umbrella tip body" refers to the
distal most portion of an umbrella tip catheter ablation
instrument. An umbrella tip body is not limited to any particular
size. An umbrella tip body may be configured for energy emission
during an ablation procedure.
[0042] As used herein, the term "lesion," or "ablation lesion," and
like terms, refers to tissue that has received ablation therapy.
Examples include, but are not limited to, scars, scabs, dead
tissue, and burned tissue.
[0043] As used herein, the term "spiral lesion" refers to an
ablation lesion delivered through a wire tip ablation catheter.
Examples include, but are not limited to, lesions in the shape of a
wide spiral, and a narrow spiral.
[0044] As used herein, the term "umbrella lesion" or "radial
lesion," and like terms, refers to an ablation lesion delivered
through an umbrella tip ablation catheter. Examples include, but
are not limited to, lesions with five equilateral prongs extending
from center point, lesions with four equilateral prongs extending
from center point, lesions with three equilateral prongs extending
from a center point, and lesions with five non-equilateral prongs
extending from center point.
[0045] As used herein, the term "conductive coil" refers to
electrodes capable of emitting energy from an energy source in the
shape of a coil. A conductive coil is not limited to any particular
size or measurement. Examples include, but are not limited to,
densely wound copper, densely wound platinum, and loosely wound
silver.
[0046] As used herein, the term "conductive plate" refers to
electrodes capable of emitting energy from an energy source in the
shape of a plate. A conductive plate is not limited to any
particular size or measurement. Examples include, but are not
limited to, copper plates, silver plates, and platinum plates.
[0047] As used herein, the term "energy" or "energy source," and
like terms, refers to the type of energy utilized in ablation
procedures. Examples include, but are not limited to,
radio-frequency energy, microwave energy, cryo-energy energy (e.g.,
liquid nitrogen), or ultrasound energy.
[0048] As used herein, the term "maze procedure," "maze technique,"
"maze ablation," and like terms, refer to what is generally known
as a cardiac ablation technique. Small lesions are made at a
specific location in the heart in a manner so as to create a
"maze." The maze is expected to prevent propagation of electrical
impulses.
[0049] As used herein, the term "central post" refers to a chamber
capable of housing small items. The central post is made from a
durable material. A central post is not limited to any particular
size or measurement. Examples include, but are not limited to,
polyurethane, steel, titanium, and polyethylene.
[0050] As used herein, the term "outer arms" refers to a shaft
capable of interfacing with electrodes and a central post. An outer
arm is not limited to any size or measurement. Examples include,
but are not limited, to titanium shafts, polyurethane shafts, and
steel shafts.
[0051] As used herein, the term "outer arm hinge" refers to a joint
(e.g., junction, flexion point) located on an outer arm. The degree
of flexion for an outer arm hinge may range from 0 to 360
degrees.
DETAILED DESCRIPTION OF THE INVENTION
[0052] The present invention provides structures that embody
aspects of the ablation catheter. The present invention also
provides tissue ablation systems and methods for using such
ablation systems. The illustrated and preferred embodiments discuss
these structures and techniques in the context of catheter-based
cardiac ablation. These structures, systems, and techniques are
well suited for use in the field of cardiac ablation.
[0053] However, it should be appreciated that the invention is
applicable for use in other tissue ablation applications. For
example, the various aspects of the invention have application in
procedures for ablating tissue in the prostrate, brain, gall
bladder, uterus, and other regions of the body, using systems that
are not necessarily catheter-based.
[0054] The multifunctional catheters of the present invention have
advantages over previous prior art devices. FIGS. 1-11 show various
preferred embodiments of the multifunctional catheters of the
present invention. The present invention is not limited to these
particular configurations.
[0055] Wire Tip Ablation Catheters
[0056] FIG. 1 illustrates an ablation catheter embodiment including
broadly an elongate catheter body 10 (e.g., hollow tube) extending
from a handle 11. Elongate catheter body 10 permits the housing of
items that assist in the ablation of subject tissue (e.g., human
tissue and other animal tissue, such as cows, pigs, cats, dogs, or
any other mammal). The elongate catheter body 10 may range in size
so long as it is not so small that it cannot carry necessary
ablation items, and not so large so that it may not fit in a
peripheral major vein or artery. The elongate catheter body 10
includes an elongate sheath 12 (e.g., protective covering). The
elongate sheath 12 may be made of a polymeric, electrically
nonconductive material, like polyethylene or polyurethane. In
preferred embodiments, the elongate sheath 12 is formed with the
nylon based plastic Pbax, which is braided for strength and
stability. In additional embodiments, the elongate sheath 12 is
formed with hypo tubing (e.g., stainless steel, titanium). The
elongate sheath 12 houses a conducting wire 13 (e.g., standard
electrical wire) and a thermal monitoring circuit 19. The
conducting wire extends from the handle 11 through the distal
opening 14. In addition, the conducting wire 13 is wrapped with a
steering spring 15. The conducting wire 13 is flexible so that it
may be flexed to assume various positions (e.g., curvilinear
positions). The steering spring 15 is controlled through
manipulation of the handle 11, as discussed below. The conducting
wire 13 is also capable of transmitting energy (e.g.,
radio-frequency energy) from an energy source 16 (e.g.,
radio-frequency energy generator).
[0057] A thermal monitoring circuit 19 (e.g., thermocouple) is
coupled with the conducting wire 13 and extends from the handle 11
through the umbrella tip body 25. The thermal monitoring circuit 19
connects with energy source cable 23 within handle 11. Regulation
of the thermal monitoring circuit 19 is achieved through the energy
source 16. In some embodiments, the present invention utilizes the
thermal monitoring circuit described in U.S. Pat. No. 6,425,894
(herein incorporated by reference), whereby a thermocouple is
comprised of a plurality of thermal monitoring circuits joined in
series. The thermal monitoring circuits are thermoconductively
coupled to the electrodes. In some embodiments, the thermal
monitoring circuit employs two wires to travel through the
elongated catheter body in order to monitor a plurality of
electrodes.
[0058] The distal opening 14 is the distal terminus of the elongate
catheter body 10. At the distal opening 14, the conducting wire 13
exits the elongate sheath 12. While the majority of the conducting
wire 13 is housed within the elongate sheath 12, the distal portion
is housed within the wire tip sheath 17. The wire tip sheath 17
begins at the distal opening 14 and extends throughout the wire tip
body 18. The wire tip sheath 17 may be made of a polymeric,
electrically nonconductive material (e.g., polyethylene or
polyurethane). In preferred embodiments, the wire tip sheath 17 is
formed with peek insulator (e.g., high temperature thermo-plastic).
A thermal monitoring circuit 19 is coupled with the conducting wire
13 and extends from the handle 11 through the wire tip body 18. The
thermal monitoring circuit 19 connects with energy source cable 23
within handle 11.
[0059] The wire tip sheath 17 permits the wire tip body 18 to be
molded or shaped into a desired position. In preferred embodiments,
the wire tip body 18 may be shaped into a unique shape (e.g.,
spiral).
[0060] In the preferred embodiment described FIGS. 1-4, the wire
tip body 18 is in the shape of a spiral. The spiral on a wire tip
body 18 may be peripheral to or central to the elongate catheter
body 10. The spiral wire tip body 18 is central if the spiral
interfaces with the distal opening 14 at the spiral center point,
and peripheral if the spiral interfaces with the distal opening 14
at the spiral exterior point. The embodiment described in FIG. 1
presents a spiral wire tip body 18 that is peripheral to the
elongate catheter body 10. Alternatively, the embodiment described
in FIG. 2 presents a spiral wire tip body 18 that is central to the
elongate catheter body. A wire tip body 18 in the shape of a spiral
may comprise any number of complete rotations (e.g., complete
spirals). In the embodiment described in FIGS. 1 and 2, the spiral
wire tip body 18 consists of two and one half complete rotations.
Alternatively, the embodiment described in FIG. 3 presents a spiral
with only two complete rotations. The distance inbetween the
spirals on the wire tip body 18 may assume any measurement.
[0061] Tissue ablation occurs on the wire tip body 18. Various
conductive elements (e.g., coils or plates) may be distributed
along the wire tip body 18. The energy utilized within a catheter
ablation instrument is released through the conductive elements.
The number of conductive elements on the wire tip body 18 permit a
determined energy release and resulting ablation lesion.
[0062] The conductive elements used in the preferred embodiment
described in FIGS. 1, 2 and 4 are conductive coils 20. Each
conductive coil 20 is an electrode that is comprised of a densely
wound continuous ring of conductive material, (e.g., silver,
copper). In preferred embodiments, the conductive coil 20 is made
from platinum. The conductive coils 20 are fitted (e.g., pressure
fitting) about the wire tip body 18. In preferred embodiments, a
conductive coil 20 is soldered onto a conductive metal (e.g.,
copper, copper with silver) and swaged onto the wire tip body 18.
Additional embodiments may utilize an adhesive seal in addition to
swaging in fixing conductive coils 20 to the wire tip body 18. A
conductive coil 20 may range in size from 0.1 mm to 20 mm. In
preferred embodiments, a conductive coil 20 ranges in size from 2
to 8 mm. The conductive coils 20 interact with the conducting wire
13 and emit the energy carried by the conductive wire 13.
[0063] Conductive coils 20 may be arranged in many different
patterns (e.g., staggered) along the wire tip body 18. Such
patterns may involve repeating sets of conductive coils 20 (e.g.,
set of 3 coils-3 coils-3 coils, etc.) or nonrepeating sets (e.g.,
set of 3 coils-5 coils-2 coils, etc.). In addition, the pattern of
conductive coils 20 may simply involve only one coil instead of
sets. The pattern of conductive coils 20 arranged in the preferred
embodiment presented in FIGS. 1, 2 and 4 consist of a repeating set
of four conductive coils 20 separated by a gap. In general, the gap
may range in size from 0.1 mm to 100 mm, and is nonconductive. In
the embodiments demonstrated in FIGS. 1, 2 and 4, the gap size is 5
mm. Within a repeating arrangement of conductive coils 20, the
spaces in between the conductive coils 20 are also nonconductive
and may range in size from 0.01 mm to 100 mm.
[0064] The conductive elements used in the preferred embodiment
described in FIG. 3 are conductive plates 21. Each conductive plate
21 is an electrode that is comprised of a solid ring of conductive
material (e.g., platinum). The conductive plates 21 are fitted
(e.g., pressure fitting) about the wire tip body 18. Additional
embodiments may utilize an adhesive seal in addition to swaging in
fixing conductive plates 21 to the wire tip body 18. A conductive
plate 21 may range in size from 0.1 mm to 20 mm. The conductive
plates 21 interact with the conducting wire 13 and emit the energy
carried by the conductive wire 13.
[0065] Conductive plates 21 may be arranged in many different
patterns (e.g., repeating sets) along the wire tip body 18. Such
patterns may involve a repeating series of conductive plates 21
separated by spaces (e.g., plate-space-plate-space-plate; etc.) or
a random series (e.g., space-space-plate-plate-plate-space-plate;
etc.). In addition, the pattern of conductive plates 21 may simply
involve only one short or extended conductive plate 19. The pattern
arranged in the preferred embodiment presented in FIG. 3 consists
of four conductive plates 21 separated by nonconductive gaps. In
general, the gaps may range in size from 0.1 mm to 100 mm. In the
FIG. 4 embodiment, the gap size is 5 mm.
[0066] The pattern of conductive elements arranged on the wire tip
body 18 need not be restricted to only a certain type. Indeed, the
present invention envisions a wire tip body 18 with varied patterns
of different conductive elements (e.g.,
coil-gap-plate-plate-gap-coil-coil; etc.).
[0067] The wire tip body 18 may be expanded or contracted through
manipulation of the handle 11. In preferred embodiments, the handle
11 connects with the conducting wire 13 with the steering spring 15
attached onto it. The conducting wire 13 attaches onto a lever 22
inside the handle 11. Extension of the lever 22 causes a
contraction in the steering spring 15 attached to the conducting
wire 13 resulting in a constricting of the wire tip body 18.
Alternatively, constriction of the lever 22 causes the steering
spring 15 to expand.
[0068] An alternative embodiment utilizes the steering method
described in U.S. Pat. No. 5,318,525 (herein incorporated by
reference). In that embodiment, a catheter tip is deflected by
means of a shapable handle coupled to pull wires fastened to the
distal end of the deflectable tip. A core wire extends from the
handle to the distal tip, providing fine positioning of the
deflectable tip by applying torque through the core wire to the
tip. A spring tube is further provided in the deflectable tip for
improved torque transmission and kink-resistance. The catheter has
an electrode at the distal end of the deflectable tip for
positioning at a target site and applying RF power to accomplish
ablation.
[0069] In other embodiments, the method of catheter manipulation
described in U.S. 2001/0044625 A1 (herein incorporated by
reference) is utilized, whereby a control element within the handle
is able to flex and deflex the distal tip. Additional embodiments
utilize the method of catheter manipulation described in U.S. Pat.
No. 6,241,728 (herein incorporated by reference), whereby three
handle manipulators permit a distal tip to be deflected
longitudinally, radially, and in a torqued position. A further
embodiment utilizes the method of catheter manipulation described
in U.S. 2001/0029366 A1 (herein incorporated by reference), whereby
a rotating cam wheel permits the steering of a distal tip in any
direction. However, other mechanisms for steering or deflecting the
distal end of a catheter according to the present invention may
also be employed. For example, the steering and deflection
mechanism as set forth in U.S. Pat. No. 5,487,757 may also be
employed to deflect the distal tip of the catheter, as well as any
other known deflection/steering mechanism. Similarly, a sliding
core wire for adjustment of the radius of curvature of the catheter
when deflected may also be employed, as also disclosed in U.S. Pat.
No. 5,487,757.
[0070] In alternative embodiments, the wire tip body 18 may be
expanded or contracted though computer assisted manipulation. In
other embodiments, the wire tip body 18 may be manipulated through
use of magnetic fields.
[0071] The terminus of the conducting wire attaches to an energy
source cable 23 that establishes a connection with the energy
source 16.
[0072] Depictions of various degrees of contraction or expansion of
the wire tip body 18 in the shape of a spiral are presented in
FIGS. 2, 3 and 4. In the fully contracted position, the regions
between the spirals on the wire tip body 18 decreases while the
spacing in between the conductive elements remains intact. As the
wire tip body 18 becomes more expanded, the regions in between
spirals on the wire tip body 18 increases, and the spacing in
between the conductive elements remains intact.
[0073] The proximal origin of the conducting wire 13 maybe located
at the distal end of the handle 11. At the proximal origin of the
conducting wire 13, the conducting wire 13 is connected with an
energy source 16 (e.g., radio-frequency energy). Embodiments of the
present invention may utilize numerous forms of energy (e.g.,
radio-frequency energy, liquid nitrogen, saline). In one
embodiment, liquid nitrogen is utilized as an energy source 16
(such embodiments employ a hollow tube that travels throughout the
catheter to deliver N.sub.2 gas) that freezes a particular tissue
region. In an additional embodiment, the energy source 16 utilized
is a saline irrigation system, whereby saline is flushed out
through a mesh of electrodes carrying an electric current.
[0074] In preferred embodiments, radio-frequency energy is utilized
as the energy source 16. Various radio-frequency energy generators
are commercially available. A large (20.times.10 cm) ground patch
24 is attached to the patient's back to complete the circuit. The
current travels from the tip of the heart to the patch. The amount
of energy utilized may be controlled by adjusting the power output
of the energy source 16. Four parameters may are regulated through
the energy source 16: power output, impedance, temperature, and
duration of energy application.
[0075] The precise pattern of conductive elements assorted on the
wire tip body 18 along with the shaped configuration of the wire
tip body 18 permits a unique type of ablation lesion ranging from
long and thin to large and deep in shape. In addition, numerous
types of ablation lesions are possible for each catheter ablator
embodiment through manipulation o the wire tip body 18.
[0076] Umbrella Tip Ablation Catheters
[0077] FIGS. 5-11 illustrate ablation catheter embodiments
including broadly an elongate catheter body 10 (e.g., hollow tube)
extending from a handle 11. The elongate catheter body 10 includes
an elongate sheath 12 (e.g., protective covering). The elongate
sheath 12 houses a conducting wire 13 (e.g., standard electrical
wire) and a thermal monitoring circuit 19. The conducting wire
extends from the handle 11 through the distal opening 14. The
conducting wire 13 is also capable of transmitting energy (e.g.,
radio-frequency energy) from an energy source 16 (e.g.,
radio-frequency energy generator).
[0078] A thermal monitoring circuit 19 (e.g., thermocouple) may be
coupled with the conducting wire 13 and extend from the handle 11
through the umbrella tip body 25. The thermal monitoring circuit 19
is connects with energy source cable 23 within handle 11.
Regulation of the thermal monitoring circuit 19 is achieved through
the energy source 16. In some embodiments, the present invention
utilizes the thermal monitoring circuit described in U.S. Pat. No.
6,425,894 (herein incorporated by reference), whereby a
thermocouple is comprised of a plurality of thermal monitoring
circuits joined in series. The thermal monitoring circuits
thermoconductively coupled to the electrodes. The thermal
monitoring circuit will require only two wires to travel through
the elongated catheter body in order to monitor a plurality of
electrodes.
[0079] The distal opening 14 is the distal terminus of the elongate
catheter body 10. The most distal portion of this embodiment is the
umbrella tip body 25. The umbrella tip body 25 consists of a
central post 26, a plurality of outer arms 27, the conductive wire
13, and conductive elements (e.g., coils).
[0080] The central post 26 extends from the distal opening 14. The
central post 26 is a chamber (e.g., hollow tube) capable of housing
small items (e.g., wire). The central post 26 may be made from
electrically nonconductive materials (e.g., polyurethane, plastic,
or polyethylene). The length of the central post 26 may range from
0.1 mm to 100 mm, and its diameter from 0.001 mm to 100 mm. The
central post 26 may be formed into numerous shapes. In the
preferred embodiments described in FIGS. 5-11, the central post 26
is in the shape of an extended cylindrical rod.
[0081] One function of the central post 26 is to house the
conducting wire 13. At the distal opening 14, the conducting wire
13 exits the elongate sheath 12. While the majority of the
conducting wire 13 is housed within the elongate sheath 12, the
distal portion is housed within the central post 26.
[0082] The outer arms 27 extend from the base of the central post
26 through the top of the central post 27. An outer arm 27 is a
shaft (e.g., post) made from an electrically nonconductive material
(e.g., polyurethane, polyethylene). The length of an outer arm 27
may range from 0.1 mm to 100 mm, and its diameter from 0.001 mm to
100 mm. In some embodiments, along the outside of an outer arm 27
is a thermal monitoring circuit 19, which is able to detect
temperature and maintain temperature.
[0083] An outer arm 27 may be flexible or rigid. In the preferred
embodiments described in FIGS. 5-11, the outer arms 27 are
flexible. The degree of flexibility may range from 0 to 360
degrees. There are several types of outer arm 27 flexibility. The
outer arm 27 flexibility displayed in FIGS. 5-11 arises from an
outer arm hinge 28 located at the outer arm's 27 midpoint and
permits a degree of flexibility from 0 to 180 degrees.
[0084] One function of the outer arms 27 is to interact with the
central post 26. The central post 26 and each outer arm 27 firmly
connect (e.g., adhere) at the top of the central post 26. The outer
arms 27 also interface (e.g., connect) at the base of the central
post 26. The outer arm 27 connections at the base of the central
post 26 may or may not also connect with the central post 27. In
the preferred embodiments described in FIGS. 5-11, the outer arms
27 interface together at the distal opening 14 at a distal opening
ring 29. The distal opening ring 29 does not connect to the central
post 26, but rather connects to the distal opening 14.
[0085] Umbrella tip bodies 26 may present a plurality of outer arms
27. The embodiments described in FIGS. 5, 10 and 11 display an
umbrella tip 26 with five outer arms 27. The embodiments described
in FIGS. 6 and 7 display an umbrella tip body 26 with three outer
arms 27. The embodiments described in FIGS. 8 and 9 display an
umbrella tip body 26 with four outer arms 27. There may be any
range of distances in between each outer arm 27 on an umbrella tip
26. In the embodiments displayed in FIGS. 5-11 the distances in
between each outer arm 27 are equilateral.
[0086] Conductive elements (e.g., plates) are distributed along the
outer arms 27. The energy utilized within a catheter ablation
instrument is released through the conductive elements. The number
of conductive elements an outer arm 27 permits a determined energy
release and resulting ablation lesion.
[0087] The conductive elements used in the preferred embodiments
described in FIGS. 5, 6, 8, and 10 are conductive coils 20. Each
conductive coil 20 is an electrode that is comprised of a densely
wound continuous ring of conductive material, (e.g., silver,
copper). In preferred embodiments, the conductive coil 20 is made
from platinum. The conductive coils 20 are fitted (e.g., pressure
fitting) about the wire tip body 18. In preferred embodiments, a
conductive coil 20 is soldered onto a conductive metal (e.g.,
copper, copper with silver) and swaged onto the umbrella tip body
25. Additional embodiments may utilize an adhesive seal in addition
to swaging in fixing conductive coils 20 to the umbrella tip body
25. A conductive coil 20 may range in size from 0.1 mm to 20 mm.
The conductive coils 20 interact with the conducting wire 13 and
emit the energy carried by the conductive wire 13.
[0088] Conductive coils 20 may be arranged in many different
patterns (e.g., staggered) along an outer arm 27. Such patterns may
involve repeating sets of conductive coils 20 (e.g., set of 3
coils-3 coils-3 coils, etc.) or nonrepeating sets (e.g., set of 3
coils-5 coils-2 coils, etc.). The pattern of conductive coils 20
may simply involve only one coil instead of sets. In addition, an
umbrella tip body 26 may vary the patterns of conductive coils 20
on each outer arm 27 to achieve an even more unique ablation
lesion. The pattern of conductive coils 20 arranged in the
preferred embodiment presented in FIGS. 5, 6, 8, and 10 consist of
two sets of four conductive coils 20 separated by a gap on each
outer arm 27 located near the distal ending. In general, the gaps
may range in size from 0.1 mm to 100 mm, and is nonconductive.
Within a repeating arrangement of conductive coils 20, the spaces
in between the conductive coils 20 are also nonconductive and may
range in size from 0.01 mm to 100 mm.
[0089] The conductive elements used in the preferred embodiment
described in FIGS. 7, 9, and 11 are conductive plates 21. Each
conductive plate 21 is an electrode that is comprised of a solid
ring of conductive material, (e.g., platinum). The conductive
plates 21 are fitted (e.g., pressure fitting) about an outer arm
27. A conductive plate 21 may range in size from 0.1 mm to 20 mm.
The conductive plates 19 interact with the conducting wire 13 and
emit the energy carried by the conductive wire 13.
[0090] Conductive plates 21 may be arranged in many different
patterns (e.g., repeating sets) along an outer arm 27. Such
patterns may involve a repeating series of conductive plates 21
separated by spaces (e.g., plate-space-plate-space-plate; etc.) or
a random series (e.g., space-space-plate-plate-plate-space-plate;
etc.). The pattern of conductive plates 21 may simply involve only
one short or extended conductive plate 21. In addition, an umbrella
tip body 26 may vary the patterns of conductive plates 21 on each
outer arm 27 to achieve an even more unique ablation lesion. The
pattern arranged in the preferred embodiment presented in FIGS. 7,
9, and 11 consists of one conductive plates 21 on each outer arm 27
located near the distal ending.
[0091] The pattern of conductive elements arranged on the umbrella
tip body 26 need not be restricted to only a certain type. Indeed,
the present invention contemplates an umbrella tip 26 with varied
patterns of different conductive elements (e.g., outer arm 1:
coil-plate-plate-coil; outer arm 2: plate-plate-coil; outer arm 3:
coil-coil; etc.).
[0092] An umbrella tip 26 may be expanded or contracted through
manipulation of the handle 11. In one type of embodiment, the base
of the central post 26 interfaces (e.g., adheres) with the
conducting wire 14. The distal opening 14 is wide enough for the
central post 26 to slide in and out of the elongate catheter body
10. Contraction of the umbrella tip 26 occurs when the central post
26 is extended out of the elongate catheter body 10. Expansion of
the umbrella tip 26 occurs when the central post 26 is extended
into the elongate catheter body 10.
[0093] Extension or retraction of the umbrella tip body 26 is
manipulated through the handle 11. In preferred embodiments, the
handle 11 connects with the conducting wire 13 and steering spring
15. The conducting wire 13 attaches onto a lever 22 inside the
handle 11. Extension of the lever 22 causes the central post 26 to
extend outside of the elongate catheter body 10. As the central
post 26 extends outside the elongate catheter body 10, the outer
arms 27 reduce the degree of flexion. Retraction of the lever 22
causes the central post 26 to withdraw inside the elongate catheter
body 10. As the central post 26 withdraws into the elongate
catheter body 10, the outer arms 27 increase the degree of
flexion.
[0094] An umbrella tip catheter may utilize numerous alternative
steering embodiments, some of which are described above in relation
to wire tip ablation catheters.
[0095] The terminus of the conducting wire attaches to an energy
source cable 23 which establishes a connection with the energy
source 16.
[0096] The proximal origin of the conducting wire 13 may be located
at the distal end of the handle 11. At the proximal origin of the
conducting wire 13, the conducting wire 13 is connected with an
energy source 16. Embodiments of the present invention may utilize
numerous forms of energy (e.g., radio-frequency energy, ultrasound,
laser, liquid nitrogen, saline-mediated).
[0097] In preferred embodiments, radio-frequency energy is utilized
as the energy source 16. Various radio-frequency energy generators
are commercially available. A large (20.times.10 cm) ground patch
24 is attached to the patient's back to complete the circuit. The
current travels from the tip of the heart to the patch. The amount
of energy utilized may be controlled by adjusting the power output
of the energy source 16. Four parameters may are regulated through
the energy source 16: power output, impedance, temperature, and
duration of energy application.
[0098] The precise pattern of conductive elements assorted on an
umbrella tip 26, along with the varying degrees of central post 26
expansion or contraction, permits a unique type of ablation lesion
ranging from long and thin to large and deep in shape.
[0099] Alternative Embodiments
[0100] The present invention is not limited to wire tip or umbrella
tip embodiments. It is contemplated that fragmented ablation
lesions may be created with alternative designs. For example,
zig-zag distal bodies, cross-hatch patterns, or other shapes may be
utilized so long as the ablation lesion that is created is
effective in prevention propagation electrical impulses.
[0101] Uses
[0102] The multifunctional catheter of the present invention has
many advantages over the prior art. The heart has four chambers, or
areas. During each heartbeat, the two uppers chambers (atria)
contract, followed by the two lower chambers (ventricles). A heart
beats in a constant rhythm--about 60 to 100 times per minute at
rest. This action is directed by the heart's electrical system. An
electrical impulse begins in an area called the sinus node, located
in the upper part of the right atrium. When the sinus node fires,
an impulse of electrical activity spreads through the right and
left atria causing them to contract, forcing blood into the
ventricles. Then the electrical impulses travel in an orderly
manner to another area called the atrioventricular (AV) node and
HIS-Purkinje network. The AV node is the electrical bridge that
allows the impulse to go from the atria to the ventricles. The
HIS-Purkinje network carries the impulses throughout the
ventricles. The impulse then travels through the walls of the
ventricle, causing them to contract. This forces blood out of the
heart to the lungs and the body. Each electrical circuit has a
wavelength. The wavelength is equivalent to the product of the
impulse's conduction velocity and the impulse's effective
refractory period.
[0103] Atrial fibrillation is the most common type of irregular
heartbeat. In atrial fribrillation, an electrical impulse does not
travel in an orderly fashion through the atria. Instead, many
impulses begin and spread through the atria and compete for a
chance to travel through the AV node. Such aberrant electrical
impulses may originate from tissues other than the heart's
electrical system.
[0104] One method of treatment for atrial fibrillation is ablation
therapy. It is estimated that for initiation of atrial
fibrillation, premature depolarizations from any cardiac structure
is necessary. However, for perpetuation of atrial fibrillation both
a continuous/continual surge of premature depolarizations and an
atrial substrate capable of maintaining multiple reentrant circuits
of atrial fibrillation are necessary. The goal of ablation therapy
is to eliminate the premature depolarizations that trigger atrial
fibrillation, and also to modify the atrial tissue such that the
minimum wavelength of a reentrant electrical circuit will not be
able to fit into the atrial tissue.
[0105] Procedurally, to eliminate triggers, a specific and
localized area of interest (e.g., area of pulmonary vein connecting
with atria, alternate group of cells emitting electrical impulses
on their own) is targeted. A catheter with an ablation instrument
is directed through a major vein or artery to the targeted location
in the left atrium. Through the ablation instrument,
radio-frequency is released onto the targeted location. A resulting
scar or lesion is created.
[0106] To modify the atrial substrate "maze" patterns of ablation
lesions are created. The intent is to create continuous lesions
without any connecting gaps.
[0107] The major shortcoming of present ablation techniques is an
inability to avoid gaps in the maze ablation process. The heart
walls have extremely complex curvatures making the creation of a
continuous ablation maze nearly impossible. The typical result is
an ablation maze containing numerous gaps. It is important to avoid
the presence of gaps within the ablation maze because aberrant
electrical impulses are able to propagate through them resulting in
secondary arrhythmias. As such, gaps become reentrant circuits, and
the atrial fibrillation is capable of continuing and different
arrhythmias such as atrial flutter may also occur. In addition,
creation of maze like lesions in atrium is extremely time consuming
and is associated with a significant complication rate.
[0108] The present multifunctional catheter overcomes the gap
problem faced in the prior art by not relying upon continuous
lesions. The present invention creates spiral or umbrella shaped
ablation lesions with very small gaps between the ablation lesions.
Each gap is not large enough to allow an electrical impulse to
propagate through it. The ablation tips of the present invention
(e.g., wire tip or umbrella tip) have a relatively small surface
area (e.g., 10-25 mm in diameter). In addition, the tips are
pliable and soft, and yet have good support form the shaft. Thus,
when the tip is pushed against the atrial wall, most, if not all,
of the surface will form good contact without the risk of
perforation as it is not a pointed catheter tip. Strategic
placement of such ablation lesions essentially decreases the
effective atrial mass that an aberrant electrical impulse may
propagate through. This represents a significant improvement over
the prior art because no longer will the laborious and often
unsuccessful creation of ablation lesion mazes be necessary. It is
also possible to use the ablation approach described in this
disclosure in conjunction with ablation strategies that target
elimination of triggers such as a pulmonary vein isolation
procedure.
[0109] The present ablation catheters may be utilized in treating
cardiac disorders including, but not limited to, atrial
fibrillation, multifocal atrial tachycardia, inappropriate sinus
tachycardia, atrial tachycardia, ventricular tachycardia,
ventricular tachycardia, and WPW. In addition, the present ablation
catheter may be utilized in several other medical treatments (e.g.,
ablation of solid tumors, destruction of tissues, assistance in
surgical procedures, kidney stone removal).
[0110] All publications and patents mentioned in the above
specification are herein incorporated by reference. Various
modifications and variations of the described devices,
compositions, methods, systems, and kits of the invention will be
apparent to those skilled in the art without departing from the
scope and spirit of the invention. Although the invention has been
described in connection with specific preferred embodiments, it
should be understood that the invention as claimed should not be
unduly limited to such specific embodiments. Indeed, various
modifications of the described modes for carrying out the invention
that are obvious to those skilled in art are intended to be within
the scope of the following claims.
* * * * *