U.S. patent application number 09/816542 was filed with the patent office on 2001-11-22 for temporary atrial cardioversion catheter.
This patent application is currently assigned to DAIG CORPORATION. Invention is credited to Coyle, Michael J., Hofstad, Michael L., Kroll, Mark W., Ockuly, John D., Scott, Steven E..
Application Number | 20010044645 09/816542 |
Document ID | / |
Family ID | 22839900 |
Filed Date | 2001-11-22 |
United States Patent
Application |
20010044645 |
Kind Code |
A1 |
Hofstad, Michael L. ; et
al. |
November 22, 2001 |
Temporary atrial cardioversion catheter
Abstract
A coronary sinus catheter includes a distal electrode portion
with optimally-spaced and sized ring electrodes and a proximal
electrode portion with at least one optimally-spaced and sized
larger surface electrode. The catheter has all or some of the
following features. First, at least one ring electrode of the
distal electrode portion includes a first diameter less than a
second diameter of at least one, more proximally disposed, ring
electrode of the distal electrode portion. Second, at least one
ring electrode of the distal electrode portion includes a first
width less than a second width of at least one, more proximally
disposed, ring electrode of the distal electrode portion. Third,
the distal electrode portion includes at least two ring electrodes
and the proximal shock electrode includes at least two larger
surface coil electrodes. Fourth, the catheter further includes a
collapsible section, adjacent the proximal electrode portion, to
facilitate positioning of the catheter within the right atrium.
Inventors: |
Hofstad, Michael L.;
(Minnetonka, MN) ; Ockuly, John D.; (Robbinsdale,
MN) ; Coyle, Michael J.; (Minneapolis, MN) ;
Kroll, Mark W.; (Minnetonka, MN) ; Scott, Steven
E.; (Chanhassen, MN) |
Correspondence
Address: |
Scott R. Cox
Suite 2200
400 West Market
Louisville
KY
40202
US
|
Assignee: |
DAIG CORPORATION
14901 DEVEAU PLACE
MINNETONKA
MN
|
Family ID: |
22839900 |
Appl. No.: |
09/816542 |
Filed: |
March 23, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09816542 |
Mar 23, 2001 |
|
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|
09224257 |
Dec 30, 1998 |
|
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|
6219582 |
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Current U.S.
Class: |
607/122 ;
604/532 |
Current CPC
Class: |
A61N 1/056 20130101;
A61N 2001/0585 20130101 |
Class at
Publication: |
607/122 ;
604/532 |
International
Class: |
A61N 001/05; A61M
025/00 |
Claims
What is claimed:
1. An atrial cardiovascular catheter comprising: an elongate
flexible member including: an electrically active distal portion
defining a first diameter; and an electrically active intermediate
portion spaced proximally from the distal portion and defining a
second diameter greater than the first diameter.
2. The catheter of claim 1 and further including a first coil
electrode proximal portion spaced about 6 to about 10 centimeters
proximally from the intermediate portion.
3. The catheter of claim 2 and further comprising: a second coil
electrode proximal portion having a length of about 6 centimeters
and being spaced about 6 to about 10 centimeters proximally from a
proximal end of the first coil electrode proximal portion.
4. The catheter of claim 3 wherein the elongate flexible member
further defines: a collapsible section for permitting an acute
angle to be formed between adjacent sections of the catheter on
opposite sides of the collapsible section.
5. The catheter of claim 4 wherein the collapsible section is
disposed distal to the first coil electrode proximal portion.
6. The catheter of claim 1 wherein the first diameter is about 6
French size and the second diameter is about 7 French size.
7. The catheter of claim 1 wherein the distal portion includes at
least one ring electrode and the intermediate portion includes at
least one ring electrode.
8. The catheter of claim 7 wherein the ring electrodes in the
distal portion have a first width that is less than a second width
of the ring electrodes in the intermediate portion.
9. The catheter of claim 8 wherein the first width is about 1
millimeter and the second width is about 2 millimeters.
10. The catheter of claim 9 wherein the first coil electrode
proximal portion has a third width different than the first and the
second width.
11. The catheter of claim 1 wherein the distal portion includes
four rings.
12. The catheter of claim 11 wherein the four rings are defined as
a first set of two rings and a second set of two rings wherein the
rings of the first set, and the rings of the second set, are spaced
apart from each other about 2 millimeters, and the first set is
located more distally than the second set and the proximal ring of
the first set is located about 8 millimeters from the distal ring
of the second set.
13. The catheter of claim 12 wherein the first set of rings of the
distal portion define an angle of about 30 to 50 degrees relative
to the second set of rings of the distal portion.
14. The catheter of claim 1 wherein the intermediate portion
includes six rings defined as a first set of two rings, a second
set of two rings, and a third set of two rings wherein the rings of
each set are spaced apart about 2 millimeters, and the first set is
located more distally than the second set and the proximal ring of
the first set is located about 3 millimeters from the distal ring
of the second set, and the proximal ring of the second set of rings
is located about 8 millimeters from the distal ring of the third
set of rings.
15. The catheter of claim 1 wherein the distal portion and the
intermediate portion each include at least one ring electrode and
each of the rings is connected to a conductor that extends from the
ring to a proximal end of the catheter for electrical connection to
a control unit external of a body of a patient.
16. The catheter of claim 15 wherein the control unit is
selectively operable in a first mode in which the conductors are
selectively connected together to electrically connect the rings in
series and in a second mode in which the conductors are controlled
independently to operate each ring independently.
17. The catheter of claim 1 wherein the elongate flexible member
defines a fluid lumen throughout its length and has at least one
distal port in communication with the lumen.
18. The catheter of claim 1 wherein a first curve forms a junction
between the distal portion and the intermediate portion and has a
radius of curvature of about 7 to about 11 centimeters with an arc
of about 30 to about 50 degrees and a second curve defines the
intermediate portion and has a radius of curvature of about 0.5
centimeters to about 2 centimeters with an arc of about 45 to about
90 degrees.
19. An atrial cardiovascular catheter comprising: an elongate
flexible member including a distal portion with at least one first
ring electrode having a first width and at least one second ring
electrode having a second width greater than the first width.
20. An atrial catheter for electrophysiology, pacing, or
cardioversion comprising: an elongate flexible member including: a
distal portion including at least one ring electrode; an
intermediate portion spaced proximally from the distal portion and
including at least one ring electrode; a first proximal coil
electrode segment being spaced proximally from the intermediate
portion; and a second proximal coil electrode segment being spaced
proximally from the first proximal coil electrode segment.
21. An atrial catheter for electrophysiology, pacing, or
cardioversion comprising: an elongate flexible member including: a
ring electrode segment with a distal portion defining a first
diameter and including at least two rings each having a width of
about 1 millimeter and a proximal portion defining a second
diameter greater than the first diameter and including at least two
rings each having a width of about 2 millimeters; and a first coil
electrode segment having a width of about 6 centimeters and being
spaced proximally about 6 to about 10 centimeters from the most
proximal ring of the proximal portion; and a second coil electrode
segment having a width of about 6 centimeters and being spaced
proximally about 6 to about 10 centimeters from the proximal end of
the first coil segment.
22. A method of cardiovascular diagnosis and therapy comprising:
inserting an elongate flexible catheter into the vascular system of
a patient; advancing an electrically active distal portion of the
catheter into the right atrium until the electrically active distal
portion is within a coronary sinus of the patient; positioning a
first electrode coil proximal segment within the right atrium
against a wall of the right atrium; and activating an electrical
signal through the electrically active distal portion and the first
electrode coil proximal segment to electrically excite the
patient's heart for cardioversion.
23. The method of claim 22 and further comprising: positioning a
second electrode coil proximal segment within a superior vena cava;
and activating the electrical signal through the second proximal
electrode simultaneously with electrical activation of the
electrically active distal portion and first electrode coil segment
to electrically excite the patient's heart for cardioversion.
24. The method of claim 23 wherein the activating step further
comprises: selectively activating the electrically-active distal
portion and the second coil electrode proximal segment as a first
pole of a bipolar system and the first coil electrode proximal
segment as a second pole of the bipolar system.
25. The method of claim 22 wherein the activating step further
comprises: applying the electrical signal to the patient's heart
independently through multiple ring electrodes of the
electrically-active distal portion for monitoring.
26. The method of claim 22 wherein the activating step further
comprises: applying the electrical signal to the patient's heart
through multiple ring electrodes of the electrically-active distal
portion electrically connected in series for defibrillation.
27. The method of claim 22 wherein the positioning step further
comprises: selectively bending a first collapsible segment of the
catheter distal to the first electrode coil proximal segment to
force the first coil segment against a wall of a right atrial
appendage of the right atrium and selectively bending a second
segment proximal to the first electrode coil proximal segment to
position a second proximal coil electrode segment within the
superior vena cava.
28. The method of claim 27 wherein the inserting and advancing step
further comprises: positioning a guide catheter within the vascular
system so that its distal end is within the right atrium and its
proximal end protrudes external to the patient's body; inserting
the catheter into the proximal end of the guide catheter and
advancing the catheter through the guide catheter until the distal
portion of the catheter exits the distal end of the guide catheter
into the right atrium; and wherein the step of selectively bending
of the catheter proximal to the first coil electrode segment
further includes: forcing the distal end of the guide catheter
distally within the right atrium to cause the selective bending of
the catheter proximal to the first coil electrode segment.
29. The method of claim 22 wherein the advancing and positioning
steps further comprise: selectively increasing rigidity of the
catheter adjacent a first collapsible segment of the catheter that
is distal to the first electrode coil proximal segment of the
catheter; selectively decreasing rigidity of the catheter adjacent
the first collapsible segment of the catheter prior to selectively
bending the first collapsible segment of the catheter distal to the
first electrode coil proximal segment to force the first coil
segment against a wall of a right atrial appendage of the right
atrium.
30. The method of claim 29 wherein the step of selectively
increasing rigidity involves disposing a guide wire within the
catheter adjacent the first collapsible segment of the
catheter.
31. The method of claim 30 wherein the step of selectively
decreasing rigidity involves disposing a distal end of the guide
wire proximal to the first collapsible segment of the catheter so
that the guide wire is no longer adjacent the first collapsible
segment.
32. A method of cardiovascular diagnosis and therapy comprising:
positioning an electrically active distal portion of a catheter
within a coronary sinus of a patient and a first electrode coil
proximal segment of the catheter within the right atrium against a
wall of a right atrial appendage; and activating an electrical
signal through the electrically active distal portion and through
the first electrode coil segment to electrically-excite the
patient's heart for cardioversion.
33. An atrial catheter for electrophysiology, pacing, or
cardioversion comprising: a ring electrode segment having: a distal
portion defining a first diameter and including at least two rings
with each ring having a first width; a proximal portion defining a
second diameter greater than the first diameter and including at
least two rings, each ring having a second width different than the
first width; and a coil electrode segment having a width
substantially greater than the first and the second width and being
spaced proximal about 6 to about 10 centimeters from the most
proximal of the proximal ring portion.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to cardiovascular catheters.
In particular, the present invention relates to a catheter for
temporary placement in the coronary sinus and right atrium for
atrial cardioversion.
[0002] Electrophysiology (EP) catheters are well recognized and
important tools for performing a variety of functions such as
recording the heart's electrical signals, pacing the heart, or
cardioverting the heart. For recording electrical activity in the
heart, EP catheters are used to record intracardiac electrograms.
When positioned in the heart, an EP catheter records the electrical
activity between a pair of electrodes at the distal end of the
catheter to provide a recordation of the electrical activity of a
localized area of the heart near the electrode pair. By using
multiple EP catheters positioned in the heart, one can map the
sequence of myocardial depolarization as an electrical impulse
traverses the heart.
[0003] EP catheters may also be used for pacing and/or
cardioversion. For pacing, a pulse of electrical current is carried
by the catheter from an external pacemaker to the heart where it
causes cardiac cells near the catheter's electrodes to depolarize.
The depolarization of these cardiac cells is then propagated across
the heart as if the impulse arose from the heart itself. For
cardioversion, a high energy electrical charge is applied to the
heart using an EP catheter causing instant and rapid depolarization
of all cardiac cells in an attempt to restore the heart to normal
sinus rhythm.
[0004] Current EP catheters include distal portions having a
variety of ring electrodes, tip electrodes, coil electrodes, and
large surface electrodes. Moreover, some systems include multiple
EP catheters. Despite the variety of catheter components and
combinations of these components on one or more EP catheters, no
prior art catheter(s) has yet achieved an optimal arrangement of
electrically-active components for a coronary sinus catheter for
atrial cardioversion.
SUMMARY OF THE INVENTION
[0005] The present invention provides a coronary sinus catheter
including a distal electrode portion with optimally-spaced and
sized ring electrodes and a proximal electrode portion with at
least one optimally-spaced and sized larger surface electrode. This
catheter reduces energy thresholds for efficacious atrial
defibrillation and allows for strategically-placed, multiple
defibrillation vectors with a single catheter. The catheter further
includes at least two distal curve portions to facilitate placement
of the distal electrode portion within the coronary sinus and the
proximal electrode portion within the right atrium and/or other
vessels.
[0006] The catheter has all or some of the following features.
First, at least one ring electrode of the distal electrode portion
includes a first diameter less than a second diameter of at least
one, more proximally disposed, ring electrode of the distal
electrode portion. Second, at least one ring electrode of the
distal electrode portion includes a first width less than a second
width of at least one, more proximally disposed, ring electrode of
the distal electrode portion. Third, the distal electrode portion
includes a first, hook-type distal curve and a second, smoother
proximal curve. Fourth, the distal electrode portion includes at
least two ring electrodes and the proximal electrode portion
includes at least two larger surface coil electrodes. Fifth, the
catheter further includes a collapsible section, adjacent the
proximal electrode portion, to facilitate positioning of the
catheter within the right atrium.
[0007] With these features, a coronary sinus catheter of the
present invention is uniquely adapted to deliver electrical signals
for monitoring and defibrillation of the right atrium and coronary
sinus region.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a schematic plan view of a catheter of the present
invention.
[0009] FIG. 2 is a sectional view of the catheter of FIG. 1 taken
along lines 2-2.
[0010] FIG. 3 is a schematic drawing of the catheter of FIG. 1 as
deployed in the coronary sinus and right atrium.
[0011] FIG. 4 is a schematic plan view of another embodiment of a
catheter of the present invention.
[0012] FIG. 5 is an enlarged sectional view of a portion of the
catheter of FIG. 4.
[0013] FIG. 6 is a schematic drawing of a catheter of an alternate
embodiment of the present invention deployed in the coronary sinus,
right atrium, and superior vena cava.
[0014] FIG. 7 is an sectional view of a portion of the catheter of
FIG. 4 with an optionally deployed guide wire.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] A temporary atrial cardioversion system 10 is shown
generally in FIG. 1. System 10 includes catheter 11, adapter 12,
and control unit 14. Catheter 11 includes elongate flexible body 18
extending between distal end 20 and proximal end 22. Catheter 11
also includes distal electrode portion 24 and proximal electrode
portion 26, separated by non-conductive region 28, as well as first
curve 30 and second curve 34.
[0016] Distal electrode portion 24 includes first pair of distal
ring electrodes 35, second pair of distal ring electrodes 36, as
well as third, fourth, and fifth pairs of proximal ring electrodes
38, 40, and 42, respectively. Transition region 50 is located
between distal ring pair 36 and proximal ring pair 38.
[0017] Adapter 12 further includes manifold 60, cable 62, and
connector 64, as well as fluid lumen 66, connector 68, and stop
cock 70. Control unit 14 includes connector 80, switch 82, and
defibrillation circuitry (not shown) as is known in the art.
[0018] Examining distal electrode portion 24 in greater detail, the
rings of each ring electrode pairs 35, 36, 38, 40, and 42 are
spaced apart from each other about 2 millimeters. Each individual
ring of ring electrode pairs 35 and 36 has a width of about 1
millimeter, while each ring of ring electrode pairs 38, 40, and 42
has a width of about 2 millimeters. Ring electrode pairs 35, 36,
38, 40, and 42 are spaced apart a distance (L1) of about 8
millimeters from each other pair along catheter body 18. Transition
region 50 is located proximally about 1 inch from distal tip
20.
[0019] A portion of distal electrode portion 24 that is distal to
transition region 50, and which includes distal ring electrode
pairs 35 and 36, has a diameter of about 6 French. The portion of
distal electrode portion 24 that is proximal to transition region
50, and which includes proximal ring electrode pairs 38, 40, and
42, has a diameter of about 7 French. The smaller diameter portion
facilitates advance of catheter 11 into the coronary sinus 106 (and
cardiac vein), as seen in FIG. 3, while the larger diameter portion
increases the strength of catheter 11 in more proximal regions. The
larger diameter of proximal ring electrode pairs 38, 40, 42
decreases defibrillation thresholds while their larger width of 2
millimeters (compared to a 1-millimeter width of distal ring pairs
35, 36) increases the current passing through them. Transition
region 50 forms a transition between the smaller diameter distal
portion and the larger diameter proximal portion of distal
electrode portion 24.
[0020] Non-conductive region 28, which separates distal electrode
portion 24 from proximal electrode portion 26, has a length (L2) of
approximately 6 to 10 centimeters extending from the most proximal
ring of ring electrode pair 42 to a distal end of proximal
electrode portion 26. However, the length of non-conductive region
28 can vary between 6 and 10 centimeters to accommodate varying
patient anatomies.
[0021] Proximal electrode portion 26, preferably has a length (L3)
of about 6 centimeters and is preferably formed of a wound platinum
coil wire to provide a low-impedance path for a cardioversion
shock. However, other large surface non-coil electrodes can be
used. Proximal electrode portion 26 preferably has a diameter of
about 7.5 French to further reduce impedance.
[0022] Manifold 60 is connected to, and is in communication with,
proximal end 22 of catheter body 18. In particular, manifold 60
includes a multi-lumen structure for permitting passage of
conductive components of cable 62 and fluid within lumen 66 to pass
through manifold 60 for communication with corresponding lumens
within catheter body 18. As will be described in greater detail
below with reference to FIG. 2, at least one fluid lumen and
multiple conductors from conductive cable 62 extend through
catheter body 18 for communication with appropriate ring electrode
pairs 35, 36, 38, 40, and 42 and fluid ports. Conductive cable 62
extends proximally from manifold 60 for communication with
connector 64, which is removably securable to a reciprocating,
multiple conductor pin connector 80 of control unit 14. Fluid lumen
66 also extends proximally from manifold 60 for fluid communication
with stop cock 70 and connector 68, which is adapted for removable
connection to a fluid-injection source (not shown). For example,
fluid lumen 66 can be used for delivering radiopaque fluid to
permit guidance of catheter 11 under fluoroscopy or for delivery of
drugs within the vascular system. Stop cock 70 selectively
regulates passage of fluid through fluid lumen 66.
[0023] Control unit 14 includes known circuitry for
electrophysiology, pacing, and cardioversion/defibrillation.
Control unit 14 further includes switch 82 for selecting at least a
cardioversion mode and a monitoring/diagnostic mode for operating
catheter 11 within a cardiovascular system. Control unit 14 permits
operating ring electrode pairs 35, 36, 38, 40, and 42 independently
for cardiac mapping or pacing, or together in series to act as a
single electrode for defibrillation/cardioversion.
[0024] Catheter body 18 is shown in cross section in FIG. 2. In
particular, catheter body 18 includes fluid lumen 90 defined by
inner wall 91 and conductor lumen 92 defined by both inner wall 92
and outer wall 94. A plurality of conductors 96 extend through a
length of lumen 92 within catheter body 18 from catheter proximal
end 22 to catheter distal end 20 for connection to a corresponding
ring of ring electrode pairs 35, 36, 38, 40, 42 or proximal
electrode coil 26. The arrangement shown in FIG. 2 is merely an
example as many configurations of a fluid lumen and multiple
conductor/conductor lumens can be used to pass fluid and electrical
current from proximal end 22 of catheter 11 to distal end 20.
[0025] In operation, as shown in FIG. 3, catheter 11 is deployed
within a cardiovascular system for placement within right atrium
102 of heart 100. Heart 100 further includes right ventricle 104,
and coronary sinus/cardiac vein 106. Catheter 11 is advanced
through the vascular system of the patient using a guide catheter
(not shown) as known in the art until catheter distal end 20 enters
right atrium 102. Catheter 11 is then further maneuvered using
fluoroscopy (by delivering radiopaque fluid via fluid lumen 90) so
that catheter distal end 20 enters coronary sinus 106 to permit
advancement of distal electrode portion 24 within coronary
sinus/cardiac vein 106. Catheter 11 is advanced into this position
as known in the art and as described in commonly-assigned Lurie, et
al., U.S. Pat. No. 5,423,772, titled: CORONARY SINUS CATHETER,
which is expressly incorporated by reference herein in its
entirety.
[0026] Catheter 11 is positioned with distal electrode portion 24
within coronary sinus 106 and non-conductive region 23 extending
across the right atrium so that proximal electrode coil portion 26
is adjacent to and/or is forced against a wall of right atrium 102
as shown. Control unit 14 (see FIG. 1) is manipulated to activate
ring electrode pairs 35, 36, 38, 40, and 42 of distal electrode
portion 24 within coronary sinus/cardiac vein 106 to obtain
diagnostic information about cardiac electric pathways of the
heart. In this mode, each ring of the ring electrode pairs 35, 36,
38, 40, and 42 operates independently. However, when it is desired
to defibrillate right atrium 102, switch 82 on control unit 14 is
used to select the defibrillation mode for control unit 14 thereby
causing ring electrode pairs 35, 36, 38, 40, and 42 to be
electrically-connected in series to act as one large electrode.
Using control unit 14, a defibrillation electrical signal is
applied through distal electrode portion 24, acting as a cathode,
and proximal electrode portion 26, acting as an anode. As shown in
FIG. 3, this arrangement produces a defibrillation vector through
the atrial septum and a portion of the exterior atrial walls.
Control unit 14 also can be operated so that distal electrode
portion 24 acts as the anode, and proximal electrode portion 26
acts as the cathode to direct the defibrillation vector in an
opposite direction.
[0027] Catheter 11 of the present invention provides numerous
advantageous features. Distal electrode portion 24 includes ring
electrode pairs 35, 36, having a narrower first width and a smaller
first diameter than ring electrode pairs 38, 40, 42. This
arrangement in the more distal portions of catheter 11 enhances
entry and positioning of catheter 11 into the coronary
sinus/cardiac vein 106 and application of current in the coronary
sinus/cardiac vein 106. In particular, the smaller diameter portion
of distal electrode portion 24 is thinner and more flexible,
allowing further penetration into the distal coronary sinus and
cardiac vein while its narrower ring electrodes (1-millimeter
width) reduce the current that passes through the more fragile
distal coronary sinus and cardiac vein. In contrast, the larger
diameter portion of distal electrode portion 24 is thicker and less
flexible, increasing strength in catheter 11, while its larger
diameter ring electrodes decreases defibrillation thresholds and
its greater width ring electrodes increase the current passing
through them into the cardiac tissue.
[0028] An alternate embodiment of a temporary atrial cardioversion
catheter of the present invention is shown generally in FIG. 4.
System 110 includes catheter 111, adapter 112, and control unit
114. Catheter 111 includes flexible catheter body 118, distal end
122 and proximal end 123, with distal electrode portion 124 and
proximal electrode portion 126 separated by non-conductive portion
155. Catheter body 118 includes first curve 130, second curve 132,
collapsible region 134, and transition region 150. Distal electrode
portion 124 includes distal ring electrode pairs 135 and 136, as
well as proximal ring electrode pairs 138, 140, and 142. Proximal
electrode section 126 includes first coil electrode 152 and second
coil electrode 154, separated by non-conductive region 155.
Non-conductive region 155 has a length of approximately 6 to 10
centimeters, while coil electrodes 152 and 154 each have a length
of about 6 centimeters. System 110 further includes manifold 160,
conductive cable 162, connector 164, as well as fluid lumen 166,
connector 168 and stop cock 170.
[0029] Except for the addition of collapsible region 134 and a
second, more proximal coil electrode 154, catheter 111 and system
110 have substantially the same features and attributes as catheter
11 and system 10, as described in connection with FIGS. 1-3.
However, these added features of collapsible region 134 and coil
electrode 154 greatly affect the manner of operation of catheter
111, as compared to catheter 11.
[0030] Catheter 111 includes a lumen structure substantially
similar to that shown in FIG. 2 for catheter 11. However, as shown
in FIG. 5, collapsible region 134 includes outer catheter wall 180
(for illustrative purposes, an inner catheter wall like wall 91 in
FIG. 2 is not shown) that is corrugated or thinner, and/or that
omits reinforcing material in the catheter wall sufficient to
permit the catheter to be bent more easily at that location. In one
example, catheter body 118 has a mutli-layer wall that includes a
braided reinforcing material that extends the length of catheter
body 118 except at collapsible region 134, where the braid is
interrupted or omitted over the length of collapsible region 134.
Alternatively, collapsible region 134 is defined by a bond member
that is free of reinforcing material and that is secured between
two separate braided shafts of the catheter which extend distally
and proximally, respectively, from the bond member to define
catheter body 118.
[0031] In operation, as shown in FIG. 6, catheter 111 is inserted
into the right atrium and coronary sinus 106 in a manner similar to
that described in connection with FIG. 3. In particular, catheter
111 is maneuvered so that distal electrode portion 124 extends
within coronary sinus 106 (and cardiac vein) with nonconductive
portion 128 extending across right atrium 102. However, as shown in
FIG. 6, guide catheter 200 plays a prominent role in positioning
catheter 111 within right atrium 102. Using distal end 202 of guide
catheter 202, coil electrode 152 is forced toward the right atrial
appendage of right atrium 102 with collapsible region 134
facilitating the bending of catheter 11 into this position. By
further distally advancing distal end 202 of guide catheter 200, a
temporary bend in catheter body 118 is also forced at location 210,
just proximal to coil 154 to cause the remaining proximal portion,
including non-conductive region 152, to extend upwardly through
right atrium so that proximal coil electrode 154 extends within the
superior vena cava.
[0032] With catheter 111 placed in this arrangement within right
atrium 102, as shown in FIG. 6, control unit 114 is activated so
that ring electrode pairs 135, 136, 138, 140, and 142 of distal
electrode portion 124 are electrically connected in series as one
large electrode. Next, a defibrillation electrical signal is
applied to catheter 111, producing two defibrillation vectors A and
B, originating from coil electrode 152 (acting as an anode),
directed simultaneously both to coil electrode 154 and to ring
electrode pairs 135, 136, 138, 140, and 142 of distal electrode
portion 124 (both acting as cathodes).
[0033] Deploying catheter 111 in this manner permits a simultaneous
application of two defibrillation vectors A and B to more
effectively defibrillate the right atrium to terminate atrial
defibrillation. This three-electrode arrangement reduces energy
thresholds for achieving efficacious atrial defibrillation as
compared to a two electrode arrangement. Moreover, while FIG. 6
illustrates first coil electrode 152 acting as an anode and distal
electrode portion 24 with second coil electrode 154 acting as a
cathode, control unit 114 can be operated to selectively designate
the polarity of first and second electrode coil segments 152, 154
and distal electrode portion 24 to produce other cathode/anode
combinations.
[0034] During advancement of catheter 111 into and through guide
catheter 200 and right atrium 102, a relatively stiff guide wire or
stylet 250 is optionally removably disposed within an inner lumen
252 (like lumen 91 of catheter 11 as shown in FIG. 2) of catheter
111 as shown in FIG. 7 for maintaining sufficient rigidity in
collapsible region 134 during positioning of catheter 111. In
particular, guide wire 250 selectively extends both proximally and
distally of collapsible region 134 to maintain the desired rigidity
during placement of catheter 111 within coronary sinus 106 and
adjacent the right atrial appendage of right atrium 102. Just prior
to selective bending of collapsible region 134 (see FIG. 6), a
distal end of guide wire 250 is positioned proximally relative to
collapsible region 134 to permit the selective bending step to
occur. Guide wire 250 has a length sufficient to extend proximally
from distal regions of catheter 111, such as collapsible region
134, to manifold 160. Accordingly, guide wire 250 extends
proximally outward from manifold 160 through a lumen within
manifold 160 (not shown) that is in communication with inner lumen
252 and fluid lumen 166 so that guide wire 250 can extend
proximally outward from lumen 166 for manipulation. Of course, a
proximal end of lumen 166 can be adapted as necessary, as known to
those skilled in the art, to permit insertion, removal, and
manipulation of guide wire 250 through lumen 166. Finally, catheter
111 optionally can includes other inner lumen configurations to
permit the use of guide wire 250 and/or injection of a fluid (e.g.,
radiopaque fluid or medicants).
[0035] A catheter of the present invention provides numerous
advantageous features. This catheter of the present invention
includes a distal electrode portion having a smaller first diameter
portion and a larger, second diameter more proximal portion. This
arrangement, in the more distal portions of the catheter, allows
further penetration of the catheter into the coronary sinus/cardiac
vein 106. Narrower ring electrodes in the most distal portions of
the catheter reduce the current that passes through the more
fragile distal coronary sinus and cardiac vein. In contrast, wider
ring electrodes in the larger diameter proximal portion increases
the current passing into the cardiac tissue.
[0036] Moreover, a three-electrode catheter of the present
invention, in which the group of ring electrodes and the two
proximal coil electrodes are activated in various cathode/anode
combinations, reduces the energy thresholds for achieving atrial
defibrillation. Finally, the catheter of the present invention
optionally includes a collapsible section adjacent one of the
electrodes to ease placement of the adjacent electrode against a
wall of the right atrium.
[0037] Although the present invention has been described with
reference to preferred embodiments, workers skilled in the art will
recognize that changes may be made in form and detail without
departing from the spirit and scope of the invention.
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