U.S. patent application number 11/081284 was filed with the patent office on 2005-07-21 for catheter system for delivery of therapeutic compounds to cardiac tissue.
Invention is credited to Lesh, Michael D..
Application Number | 20050159727 11/081284 |
Document ID | / |
Family ID | 22278040 |
Filed Date | 2005-07-21 |
United States Patent
Application |
20050159727 |
Kind Code |
A1 |
Lesh, Michael D. |
July 21, 2005 |
Catheter system for delivery of therapeutic compounds to cardiac
tissue
Abstract
This is a method and an apparatus for the treatment or
introduction of contrast fluids into tissue, particularly cardiac
tissue. The apparatus includes a catheter having an elongated
flexible body and a tissue infusion apparatus including a hollow
infusion needle configured to secure the needle into the tissue
when the needle is at least partially inserted into the tissue to
help prevent inadvertent removal of the needle from the tissue.
This permits the selected treatment or contrast fluid to be
confined to a specific site. The catheter may also include a
visualization assembly including a transducer at the distal end of
the body.
Inventors: |
Lesh, Michael D.; (Mill
Valley, CA) |
Correspondence
Address: |
MORRISON & FOERSTER LLP
425 MARKET STREET
SAN FRANCISCO
CA
94105-2482
US
|
Family ID: |
22278040 |
Appl. No.: |
11/081284 |
Filed: |
March 15, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11081284 |
Mar 15, 2005 |
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10639896 |
Aug 12, 2003 |
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10639896 |
Aug 12, 2003 |
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09797483 |
Feb 28, 2001 |
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6716196 |
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09797483 |
Feb 28, 2001 |
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08403553 |
Mar 14, 1995 |
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08403553 |
Mar 14, 1995 |
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08100086 |
Jul 30, 1993 |
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Current U.S.
Class: |
604/522 ;
604/264 |
Current CPC
Class: |
A61M 25/0147 20130101;
A61M 25/0133 20130101; A61B 2017/00243 20130101; A61M 25/0084
20130101; A61B 2018/1435 20130101; A61M 25/0136 20130101; A61N 7/02
20130101; A61B 2018/00815 20130101; A61B 2017/3488 20130101; A61B
2018/1425 20130101; A61B 2090/3784 20160201; A61B 2017/22082
20130101; A61B 2018/00273 20130101; A61B 17/22 20130101 |
Class at
Publication: |
604/522 ;
604/264 |
International
Class: |
A61M 031/00 |
Claims
1-77. (canceled)
78. A catheter system for delivery of a therapeutic compound to
cardiac tissue through the endocardium comprising: a) an elongated
catheter body for advancing into the heart, the catheter body
having a proximal end, a distal end and an internal longitudinal
lumen; the internal lumen of the catheter body being fluidly
coupled to a fluid delivery port for receiving a gene therapy
agent; and a hollow penetrating structure for inserting into
cardiac tissue, the penetrating structure being mounted to the
distal end of the catheter body and having an internal lumen
fluidly coupled to the internal lumen of the catheter body, and b)
a source of said gene therapy agent wherein said gene therapy agent
is deliverable into the cardiac tissue through said penetrating
structure.
79. The catheter system of claim 78 wherein the gene therapy agent
comprises a modified gene.
80. The catheter system of claim 78 wherein the gene therapy agent
comprises an antisense polynucleotide.
81. The catheter system of claim 80 wherein the antisense
polynucleotide is introduced using a retroviral vector.
82. A method for delivering a gene therapy agent to a cardiac
tissue delivery site comprising the steps: a) selecting a cardiac
tissue delivery site; b) selecting the gene therapy agent for
delivery; and c) selecting a catheter system comprising an
elongated catheter body having a proximal end, a distal end an
internal longitudinal lumen; and a needle mounted to the distal end
of the catheter body and fluidly coupled to the internal lumen of
the catheter body; the internal lumen of the catheter body being
fluidly coupled to a fluid delivery port for receiving the gene
therapy agent under pressure.
83. The method of claim 82 further comprising the step of at least
partially inserting the needle into the cardiac tissue delivery
site.
84. A catheter system for delivery of a therapeutic compound to
cardiac tissue through the endocardium comprising: a) an elongated
catheter body for advancing into the heart, the catheter body
having a proximal end, a distal end and an internal longitudinal
lumen; the internal lumen of the catheter body being fluidly
coupled to a fluid delivery port for receiving a gene therapy
agent; and a hollow penetrating structure for inserting into and
attaching to cardiac tissue, the penetrating structure being
mounted to the distal end of the catheter body and having an
internal lumen fluidly coupled to the internal lumen of the
catheter body, and b) a source of said gene therapy agent wherein
said gene therapy agent is deliverable into the cardiac tissue
through said penetrating structure.
85. A method for delivering a gene therapy agent to a cardiac
tissue delivery site comprising the steps: a.) selecting a cardiac
tissue delivery site; b.) selecting the gene therapy agent for
delivery; and c.) selecting a catheter system comprising an
elongated catheter body having a proximal end, a distal end
attachable to the cardiac tissue delivery site and an internal
longitudinal lumen; the internal lumen of the catheter body being
fluidly coupled to a fluid delivery port for receiving the gene
therapy agent under pressure and delivering it into the cardiac
tissue delivery site.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. Ser. No.
08/403,553, filed Mar. 14, 1995, which in turn is a continuation of
U.S. Ser. No. 08/100,086, filed Jul. 30, 1993, the contents of both
are hereby incorporated by reference into the present
disclosure.
BACKGROUND OF THE INVENTION
[0002] Abnormal heart beats or cardiac arrhythmias can cause
significant morbidity and mortality. These arrhythmias arise from a
variety of causes, including atherosclerotic heart disease,
ischemic heart disease, metabolic or hemodynamic derangements,
rheumatic heart disease, cardiac valve disease, certain pulmonary
disorders and congenital etiologies. The normal heart rate is about
60 to 100 beats per minute. Arrhythmias refer to tachycardias at
rates exceeding 100 beats per minute for a duration of at least 3
beats. Sometimes no treatment is required, such as in the
tachycardia following a physiologic response to stress or exercise.
However, in some cases, treatment is required to alleviate symptoms
or to prolong the patient's life expectancy.
[0003] A variety of treatment modalities exist, including electric
direct current cardioversion, pharmacologic therapy with drugs such
as quinidine, digitalis, and lidocaine, treatment of an underlying
disorder such as a metabolic derangement, and ablation by either
percutaneous (closed chest) or surgical (open chest) procedures.
Treatment by ablation involves destruction of a portion of cardiac
tissue which is functioning abnormally electrically.
[0004] Normally the heart possesses an intrinsic pacemaker function
in the sinoatrial (SA) node which is in the right atrium, adjacent
to the entrance of the superior vena cava. The right atrium is one
of four anatomic chambers of the heart. The other chambers are the
right ventricle, the left atrium, and the left ventricle. The
superior vena cava is a major source of venous return to the heart.
The SA node is an area of specialized cardiac tissue called
Purkinje cells and which usually measures roughly III centimeters
by about 2 k millimeters. An electrical impulse normally exits from
the SA node and travels across the atrium until it reaches the
atrioventricular (AV) node. The AV node is located in the right
atrium near the ventricle.
[0005] Emerging from the AV node is a specialized bundle of cardiac
muscle calls which originate at the AV node in the interatrial
septum. This "bundle of His" passes through the atrioventricular
junction and later divides into left and right branches which
supply the left and right ventricles. The left and right bundles
further give rise to branches which become the so called distal
His-Purkinje system which extends throughout both ventricles.
[0006] Thus in a normal situation an impulse originates
intrinsically at the SA node, transmits through the atrium and is
modified by the AV node. The AV node passes the modified impulse
throughout the left and right ventricles via the His-Purkinje
system to result in a coordinated heartbeat at a normal rate.
[0007] Many factors affect the heart rate in addition to the
intrinsic conduction system. For example, normally the heart rate
will respond to physiologic parameters such as stress, exercise,
oxygen tension and vagal influences. Additionally, there are
multiple causes for an abnormal heartbeat such as an abnormal
tachycardia One group of such causes relates to abnormalities in
the heart's conduction system. For example, ectopic or abnormally
positioned nodes may take over the normal function of a node such
as the SA or AV node. Additionally, one of the normal nodes may be
diseased such as from ischemic heart disease, coronary artery
disease or congenital reasons. Similarly, a defect can exist in an
important part of the conduction system such as the bundle of His
or one of the bundle branches supplying the ventricles.
[0008] Treatment of abnormal tachycardias arising from ectopic foci
or so-called ectopic pacemakers can include pharmacologic therapy
or ablative therapy. The ablative therapy may be accomplished by
percutaneous insertion of a catheter or by an open surgical cardiac
procedure.
[0009] Cardiac arrhythmias may be abolished by ablating the tissue
responsible for the genesis and perpetuation of the arrhythmias.
Steerable ablation catheters using radio frequency (RF) energy are
known. The RF energy can be directed to the area to be ablated and
causes destruction of tissue by heat. In addition, direct infusion
of ethanol has been performed during open heart surgery. Ethanol
has also been infused into coronary arteries to ablate a focus such
as a ventricular arrhythmia focus or the AV node. Unfortunately
this tends to result in a fairly large region of cardiac tissue
death or myocardial infarction. With transarterial infusion there
is difficulty in precisely controlling the location and extent of
the ablation.
[0010] Thus, the prior art lacks catheters useful for direct
endocardial infusion of sclerosing agents at the precise location
of tachycardia The present invention addresses these and other
needs.
SUMMARY OF THE INVENTION
[0011] The present invention is directed to methods and devices for
delivery of desired compounds (e.g., ablation liquids) to cardiac
and other tissue using a novel hollow infusion needle. The needle
is typically used to inject an ablation liquid endocardially to
produce a more circumscribed lesion than that possible using prior
art infusion techniques. The needle is designed such that it can be
imbedded in and secured to the tissue to be treated.
[0012] Although ablation of cardiac tissue is a preferred use of
the catheters of the invention, they can be used to inject desired
compositions for a wide variety of uses. Virtually any therapeutic
compound can be delivered intracardially using the catheters of the
invention. For instance, the catheters can be used to deliver
compositions comprising modified genes to cardiac or other tissue
for use in gene therapy protocols. Methods for introducing a
variety of desired polynucleotides to target cells using, for
example, retroviral vectors are well known. Examples of sequences
that may be introduced include antisense polynucleotides to control
expression of target endogenous genes. In addition, genes encoding
toxins can be targeted for delivery to cancer cells in tumors. In
other embodiments, homologous targeting constructs can be used to
replace an endogenous target gene. Methods and materials for
preparing such constructs are known by those of skill in the art
and are described in various references. See, e.g., Capecchi,
Science 244:1288 (1989).
[0013] Other uses include intramyocardial delivery of isolated
cells or cell substitutes. These approaches typically involve
placement of the desired cells on or within matrices or membranes
which prevent the host immune system from attacking the calls but
allow nutrients and waste to pass to and from the calls (see,
Langer et al., Science 260:920-925 (1993)). For instance, sinus
node cells can be implanted in a desired location to treat
disorders in impulse formation and/or transmission that lead to
bradycardia.
[0014] For use in ablation of cardiac tissue, the catheters of the
invention have an elongated flexible body and a tissue ablation
assembly having a tissue ablation tip, at the distal end of the
body. The distal end of the catheter is introduced into a cardiac
chamber (or other body region) including the tissue to be ablated.
The catheter may be equipped for standard arrhythmia mapping, for
example multiple electrodes may be present on the outside of the
catheter for recording endocardial electrograms. Alternatively, the
catheter may include a visualization assembly at the distal end of
the body. The visualization assembly is used to position the tip of
the catheter adjacent the tissue to be ablated. Catheters
comprising visualization and ablation means are described in
copending application, Attorney Docket No. 2307F-449, which is
incorporated herein by reference.
[0015] The tissue ablation assembly comprises a hollow infusion
needle which can be extended or withdrawn from the distal end of
the catheter. The hollow infusion needles of the invention have a
securing element configured to engage tissue when the needle is at
least partially inserted into the tissue to stop recoil and help
prevent inadvertent removal of the needle from the tissue. The
securing element can be configured into the form of corkscrew or
threads surrounding a straight needle. Alternatively, the securing
element can be configured as a plurality of pre-curved needles,
which curve towards or away from the longitudinal axis of the
catheter. The pre-curved needles can also be used to deliver
ablation compounds of desired. Other structures, such as barbs,
could also be used as the securing element. The hollow infusion
needle is preferably a corkscrew-shaped needle, with a tight curl.
The distance between turns is preferably about 0.5 mm or less. Such
a needle allows the practitioner to inject through layers by slowly
extending the needle, injecting, extending farther and injecting
again.
[0016] When used to ablate tissue the catheter can be used with a
conventional ablation compounds such as alcohol (e.g., ethanol),
collagen, phenol, carbon dioxide and the like. The solution may
comprise various components for other purposes as well. For
instance, an echocontrast agent for echo imaging may be included.
Collagen can also be bound to an iodinated molecule to make it
radiodense. Alternatively, when used for gene therapy protocols,
the catheters of the invention can be used to introduce desired
polynucleotides to the target tissue.
[0017] When performing a percutaneous or closed chest cardiac
ablation procedure using the catheters of the invention,
fluoroscopy can be used to visualize the chambers of the heart.
Fluoroscopy uses roentgen rays (X-rays) and includes use of a
specialized screen which projects the shadows of the X-rays passing
through the heart. Injectable contrast agents to enhance the
fluoroscopic picture are well known in the art and are not
described in detail here.
[0018] Typically, the catheter is placed in an artery or a vein of
the patient depending on whether the left (ventricle and/or atrium)
or right (ventricle and/or atrium) side of the heart is to be
explored and portions thereof ablated. Frequently an artery or vein
in the groin such as one of the femoral vessels is selected for
catheterization. The catheter is passed via the blood vessel to the
vena cava or aorta, also depending on whether the right or left
side of the heart is to be catheterized, and from there into the
appropriate atrium and/or ventricle.
[0019] The catheter is generally steerable and it is positioned
against an endocardial region of interest. As mentioned above, the
catheter typically includes a means for sensing the electrical
impulses originating in the heart. Thus, the electrode catheter can
provide a number of electrocardiogram readings from different areas
of the internal aspects of the heart chambers. These various
readings are correlated to provide an electrophysiologic map of the
heart including notation of normal or abnormal features of the
heart's conduction system. Once the electrophysiologic map is
produced, an area may be selected for ablation.
[0020] Typically, before final ablation, the suspect area is
temporarily suppressed or deadened with a substance such as
lidocaine or iced saline solution. Subsequently the area is
remapped and the heart reevaluated to determine if the temporary
measure has provided some electrophysiologic improvement If
improvement has occurred, then the clinician may proceed with
permanent ablation typically using ethanol.
[0021] In one aspect, the present invention provides the novel
combination of tissue ablation and tissue imaging in a single
catheter to permit ablation of tissue to be properly accomplished
by the correct selection of the ablation site and monitoring and
controlling the ablation of the tissue being destroyed. The
invention is preferably used with imaging ultrasonic transceivers
in an ablation catheter to provide real time assessment of lesion
volume and to monitor the tissue being ablated. Alternatively, one
or more A-mode ultrasonic crystals can be used. As used herein, a
visualization means of the invention may be either an imaging or an
A-mode ultrasonic device. One or more transponder can also be used
to assist in localizing the catheter tip.
[0022] Other features and advantages of the invention will appear
from the following description in which the preferred embodiments
have been set forth in detail in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is an overall view of a catheter made according to
the invention;
[0024] FIG. 2 is an enlarged, simplified cross-sectional view of
the distal end of the flexible body of FIG. 1;
[0025] FIG. 3 is an enlarged, schematic cross-sectional view of the
distal end of the flexible body of FIG. 1 illustrating the general
locations of the tip electrode, ultrasonic transducer, and ring
electrodes;
[0026] FIG. 4 is an overall view of an alternative catheter made
according to the invention;
[0027] FIG. 5 is an enlarged, simplified cross-sectional view of
the tip and the catheter of FIG. 4, shown with a hollow needle
retracted;
[0028] FIG. 6 is an external view of the tip of FIG. 5 with the
hollow needle extended;
[0029] FIG. 7 is an enlarged view of the needle driver and infusion
port mounted to the handle of FIG. 4.
[0030] FIG. 8 is an enlarged, simplified cross-sectional view of
the tip of a catheter with a hollow needle retracted.
[0031] FIG. 9 illustrates the handle assembly of a catheter of the
invention.
[0032] FIG. 10A is an enlarged, simplified cross-sectional view of
the tip of a catheter with the anchoring needles and hollow needle
in the retracted position.
[0033] FIG. 10B is an enlarged, simplified cross-sectional view of
the tip of a catheter with the anchoring needles and hollow needle
in the extended position.
[0034] FIG. 11A is an enlarged, simplified cross-sectional view of
the tip of a catheter with the anchoring/infusion needles in the
extended position.
[0035] FIG. 11B is an end view of catheter tip in FIG. 11A.
[0036] FIG. 12 is an and view of a catheter tip with 10
anchoring/infusion needles.
[0037] FIG. 13A is an enlarged, simplified cross-sectional view of
the tip of a catheter showing the triggering mechanism with the
anchoring/infusion needles in the retracted position.
[0038] FIG. 13B is an enlarged, simplified cross-sectional view of
the tip of a catheter showing the triggering mechanism with the
anchoring/infusion needles in the extended position.
[0039] FIG. 14 illustrates the handle assembly of a catheter of the
invention showing the trigger for releasing and retracting the
anchoring needles.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0040] FIG. 1 illustrates a catheter 2 having a handle 4 from which
a flexible body 6 extends. Flexible body 6 extends from one end 8
of handle 4 while ultrasonic cable 10 and a combination
electrode/thermistor cable 12 extend from the other end 14 of
handle 4. Distal end 16 of flexible body 6 is steerable, as
suggested by the dashed lines 18 in FIG. 1, in a conventional
manner using a steering lever 20 mounted to handle 4. Lever 20
which controls one or more steering cables 22, see FIG. 2, as is
conventional. Distal end 16 has an RF transmitting tip 24 secured
thereto. Transmitting tip 24 is connected to an appropriate RF
energy source, not shown, through lead 26 which extends along
flexible body 6, through handle 4 and through combined cable
12.
[0041] Tip 24 has a pair of axially extending bores 28,30 formed
from its distal end 32. Bore 28 is used to house an ultrasonic
transducer 34 while bore 30 is used to house a thermistor 36.
Transducer 34 is surrounded by a thermal insulating sleeve 38,
typically made of insulating material such as polyimide. The base
40 of transducer 34 has a lead 41 extending from transducer 34,
along flexible body 6, through handle 4 and through ultrasonic
cable 10. The ultrasonic transducer comprises a piezoelectric
crystal capable of operating at a standard frequency, typically
from about 5 to about 50 MHz The crystal is formed from standard
materials such as barium titanate, cinnabar, or zirconate-titanate.
The transducer 34 generates an ultrasonic pulse in response to
electrical impulses delivered through lead 41. Ultrasonic echoes
are then received by the ultrasonic transducer 34 which generates
electrical signals which are delivered to the receiving unit (not
shown). The transducer is connected to conventional transmitting
and receiving units which include the circuitry necessary for
interpreting the ultrasonic information and displaying the
information on a visual display. Signal processing may take
advantage of change in tissue density or texture as correlated with
lesion depth. The ultrasonic signal can be visualized on a two
dimensional echocardiograph or using non-imaging A-mode.
[0042] Base 40 of transducer 34 is sealed with a UV potting
adhesive 42, such as Tough Medical Bonder made by Loctite, to
provide both thermal and electrical insulation. The catheter also
comprises an ultrasonic transponder 44, shown schematically in FIG.
3, spaced about 2.5 mm from RF transmitting tip 24 at the distal
end 16 of body 6. Transponder 44 is used to help in localization of
the catheter tip as is known in the art and described in Langberg
et al., JACC 12: 218-223 (1988). In alternate embodiments, multiple
transponders can be used to help with assessing catheter tip
orientation as well.
[0043] In the embodiment of FIGS. 1-3, the ablation apparatus
exemplified by the use of RF transmitting tip 24. In addition to
tip electrode 24, catheter 2 also includes three ring electrodes
46, 47,48 positioned in a proximal direction, that is towards
handle 4 relative to tip electrode 24 and transducer 44. Electrodes
4648 (spaced 2.5 ma apart) are used to record electrical signals
produced by the heart (electrocardiograms) for endocardial mapping
using a multichannel EKG machine as is known n e art. Thermistor 36
is coupled to combination cable 12 through a lead 50 extending from
thermistor 36, to flexible body 6, through handle 4 and into
combination cable 12. Thermistor 36 is used to provide information
about the temperature of the tissue at the distal end 32 of tip
24.
[0044] Separately, the above-discussed apparatus used to create
ultrasonic visualization of the tissue to be ablated is generally
conventional. An discussed above, the ultrasonic visualization
means may be used for either imaging or A-mode. One such ultrasonic
imaging system is sold by Cardiovascular Imaging systems of
Sunnyvale, Calif. Similarly, the RF ablation system, used to ablate
the tissue, is also generally conventional, such as is sold, for
example, by EP Technologies of Sunnyvale, Calif. What is novel is
incorporating both the imaging and ablation structure into a single
catheter which permits real time visualization and accurate
positioning of the RP transmitter tip 24 with the precise location
to be ablated. The amount or volume of tissue ablated can thus be
constantly monitored during the procedure so that neither too
little nor too much tissue is ablated for maximum control and
effectiveness. The use of temperature monitoring using thermistor
36 is also generally conventional as well, but not in conjunction
with an ultrasonic imaging assembly. Instead of using RF energy to
ablate the tissue, microwave radiation, laser energy, cryoblation
or endocardial injection/infusion, for example, can be used in
conjunction with ultrasonic transducer 34.
[0045] The use of catheter 2 proceeds generally as follows. Distal
end 16 of body 6 is directed to the appropriate site using
conventional techniques and steering lever 20. Visualization of the
tissue to be ablated and localization of the tip 24 is provided by
ultrasonic transducer 34, ultrasonic transponder 44, and associated
leads and cables coupled to a conventional ultrasonic imagining
console, not shown. When tip 24 is at the site of the tissue to be
ablated, RF generator, not shown, coupled to combination cable 12,
is activated to produce RF radiation at tip 24 to ablate the
tissue. The ablation is monitored by ultrasonic transducer 34 as
well as thermistor 36 to help ensure that the proper volume of
tissue is ablated. When the proper volume of tissue is ablated,
body 6 is removed from the patient. Instead of the use of catheter
2 including an RF transmitter tip 24, the catheter could use an
ablation fluid infusion tip similar to that shown in FIGS. 4-7.
Also, preparatory to the ablation sequence, the suspect area can be
temporarily suppressed or deadened using catheter 60 using
lidocaine or iced saline solution, as discussed in the Background
section above.
[0046] Referring the reader now to FIGS. 4-7, a catheter 60 is
shown. catheter 60 includes a handle 62 from which a flexible body
64 extends. Handle 62 includes a steering lever 65 and combination
infusion port 66 and needle driver 68 at the distal end 70 of
handle 62. A pair of cables 72 extend from the proximal end 74 of
handle 62. The distal end 76 of flexible body 64 has a tip assembly
78 mounted thereto. Tip assembly 78 includes mapping electrodes So
connected to wires 82 which extend down flexible body 64, through
handle 62 and to cables 72. Mapping electrodes 80 provide the user
with a nonvisual indication of where tip assembly is by monitoring
the electro-activity of the heart muscle, as is conventional.
Electrodes So are electrically isolated from the remainder of tip
assembly 78 by an insulating sleeve 84.
[0047] A hollow needle 86 is slidably mounted within a second
insulating sleeve 88 housed within insulating sleeve 84. The needle
may be formed from standard metal alloys such as titanium alloy,
stainless steel, and cobalt steel. The needle 86 is a
corkscrew-shaped needle used to inject ablating liquid into tissue
and secure the needle to the tissue. Other designs of hollow
needles, including the use of barbs on a straight or curved needle,
can be used as well. While hollow needle 86 is shown sued with a
generally conventional mapping electrode type of catheter, it could
be used with an ultrasonic visualization assembly as shown in FIGS.
1-3, as well as other types of visualization assemblies.
[0048] A central bore 90 of hollow needle 86 is coupled to infusion
port 66 by an infusion fluid tube 92 which extends along flexible
body 64, through needle driver 68 and to infusion port 66. Threaded
needle driver 68 is connected to a tip extension 94 so that
rotating needle driver 68 causes tip extension 94 to rotate about
the axis 95 of needle 86 and to move axially within flexible body
64. This causes hollow needle 86 to rotate about axis 95 and to
move axially within sleeve 88 from the retracted position of FIG. 5
to the extended position of FIG. 6.
[0049] Rotating needle driver 68 also rotates hollow needle 86 so
that it bores into the tissue to be ablated. When properly in
position, an appropriate liquid, such as ethanol, can be infused
into the tissue to be ablated through infusion port 66, infusion
fluid tube 92, hollow needle 86, and into the tissue. Since the tip
100 of hollow needle 86 is buried within the tissue to be ablated,
the operator is assured that the ablation liquid is delivered to
the proper place while minimizing ablation of surrounding
tissue.
[0050] Turning now to FIG. 8, the distal end 102 of a catheter of
the present invention is shown. The hollow corkscrew infusion
needle 104 is movably positioned within flexible distal tube 106.
The flexible tube 106 allows movement of the distal end 102 in
response to the steering mechanism 112. The steering mechanism 112
is conventional and functions as is known in the art. The distal
end 102 also comprises mapping electrodes 108 which monitor electro
activity of the heart muscle as described above. The mapping
electrodes are connected through signal wires 111 to standard
multichannel EKG machine as is known in the art.
[0051] The braided torque tube 114 is connected to the inside
diameter of the infusion needle 104 and provides means for rotating
the infusion needle 104 about the longitudinal axis 105 of the
catheter and moving the needle 104 axially within the distal tube
106. The braided torque tube 114 consists of standard flexible
tubing overlapped with a wire braid which stiffens the tube and
allows torquing of the tube to rotate the needle 104.
[0052] FIG. 9 shows the handle assembly 115 of a catheter of the
present invention. The braided torque tube 114 is connected to an
infusion needle advance/retract knob 116 by which the user controls
axial movement of the infusion needle 104. A female luer lock
infusion port is positioned on the advance/retract knob 116. A
standard strain relief means 118 prevents kinking of the flexible
tube 119. Also provided is a handle 120 secured to the catheter
through front handle support 122 and rear handle support 124. The
handle assembly 115 is attached to a standard steering/mapping
catheter handle 130 as is conventional and signal wires 132 are
connected to the appropriate receiving units.
[0053] FIGS. 10A through 10C show the distal end 134 of a catheter
comprising an infusion needle 136 connected to a braided torque
tube 138 as described above. The distal tube 142 also comprises an
elastomeric seal 152 made from standard materials well known to
those of skill in the art. The elastomeric seal 152 provides a seal
for the distal tube 142 and prevents blood from flowing into the
lumen of the catheter. Typically, the infusion needle 136 is coated
with a compound such as mold release, to facilitate movement of the
needle through the elastomeric seal 152.
[0054] Also included in this embodiment is a set of spring loaded
pre-curved anchoring needles 144 positioned near the outer edge of
the distal tube 142. The anchoring needles are attached to a
shuttle 150 and compression spring 146 which are triggered through
pull wires 148 through a trigger device on the handle. The function
of the trigger device is shown more fully in FIGS. 13A, 13B and
14.
[0055] FIG. 10B shows the extended anchoring needles 144 after the
triggering device has released the shuttle 150 and compression
spring 146. This mechanism permits the distal end of the catheter
to be attached in an almost instantaneous fashion and eliminates
the effects of cardiac motion on the attachment procedure.
[0056] FIG. 10C is an end view of the distal end 134 showing the
position of the pre-curved anchoring needles 144 after release. In
the embodiment shown here, the anchoring needles 144 are curved
towards the longitudinal axis of the catheter. The anchoring
needles 114, however, can be curved towards or away from the
longitudinal axis.
[0057] FIGS. 11A and 11B show a further embodiment of the catheter
comprising anchoring needles 162 which are used for infusion as
well as anchoring. In this embodiment, the needles 162 are
connected to infusion channel 160 through which the ablation liquid
or other compound is delivered to the infusion needles 162. The
infusion needles 162 are shown in the extended position after the
shuttle 166 and compression spring 164 have moved the needles 162
axially through the distal tube 156. As with other embodiments, map
electrodes 154 can be used to create an electro physiological map
of the tissue. Braided tube 158 is used to anchor the compression
spring 164. The infusion needles are curved outward as well as
inward in this embodiment (FIG. 11B).
[0058] FIG. 12 is an end view of the distal end 168 of a catheter
of the invention showing the arrangement of infusion needles 170 in
which five needles project away from the longitudinal axis and five
project toward the axis.
[0059] FIGS. 13A and 13B illustrate the trigger assembly by which
the pre-curved needles 200 are released from the distal end 202 of
the catheters of the present invention. FIG. 13A shows the
pre-curved needles 200 in the retracted position within the
flexible distal tube 204. The pre-curved needles 200 are attached
to the shuttle 206 which is held in place by three trigger tabs
208, two of which are illustrated in FIG. 13A. The trigger tabs 208
are permanently fixed to the front stop 210 and pre-loaded against
the inner diameter 212 of the distal tube 204.
[0060] As in the other embodiments disclosed above, the pre-curved
needles 200 are fluidly connected to infusion channel 214, which
enters the flexible distal tube distal 204, through braided tube
211. Map electrodes 216 are used to create an electro physiological
map of the heart as described.
[0061] FIG. 13B shows the pre-curved needles 200 in the extended
position after the trigger tabs 208 have been pulled towards the
longitude axis of the catheter by the trigger pull wires 220. Once
the trigger tabs 208 have been pulled towards the longitude axis,
the shuttle 206 is released and the compression spring 222 drives
the shuttle 206 and needles 200 rapidly towards the distal tip of
the catheter. The inertia of the catheter body prevents the tip
from withdrawing and needles 200 are subsequently driven into the
target tissue. FIG. 13B also shows the position of the trigger tabs
208 an the inner diameter of the shuttle 206 after the shuttle 206
has moved forward. After use the shuttle pull wires 218 are
activated to pull the pre-curved needles 200 to the retracted
position.
[0062] FIG. 14A shows the handle assembly 230 comprising a handle
body 232 from which this position and ablation tip steering lover
234. The handle body 232 comprises a needle trigger 236 Which is
shown in both the cocked and fired (dashed lines) positions. The
distal end of the trigger wires 238 are attached between the distal
end 240 and the pivot point 242 to insure the wires 238 are pulled
when the lever is pulled. The retractor 244 is shown in the cocked
and fired (dashed lines) positions, as well. The pull wires 244 are
attached between the pivot point 246 and the distal end of the
retractor 248 as for the trigger. The handle assembly includes a
lead 250 which allows for connection to appropriate ablation
compound as described above.
[0063] Modification and variation can be made to the disclosed
embodiments without departing from the subject of the invention as
defined in the following claims.
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