U.S. patent application number 11/596650 was filed with the patent office on 2008-03-06 for electrophysiology system for mapping and ablating arrhythmias.
Invention is credited to Ding Sheng He, David MacAdam.
Application Number | 20080058794 11/596650 |
Document ID | / |
Family ID | 35450613 |
Filed Date | 2008-03-06 |
United States Patent
Application |
20080058794 |
Kind Code |
A1 |
MacAdam; David ; et
al. |
March 6, 2008 |
Electrophysiology System for Mapping and Ablating Arrhythmias
Abstract
An electrophysiology system for mapping and/or ablating tissue
includes a catheter having a plurality of electrically active
sites. The system includes a controller providing a user interface
through which the plurality of sites may be controlled. The sites
may be accessed individually or in groups. In addition, the order
and timing of the accessing of specific electrically active sites
may be controlled in a manual or automated fashion.
Inventors: |
MacAdam; David; (Millbury,
MA) ; He; Ding Sheng; (Tyngsboro, MA) |
Correspondence
Address: |
WOLF GREENFIELD & SACKS, P.C.
600 ATLANTIC AVENUE
BOSTON
MA
02210-2206
US
|
Family ID: |
35450613 |
Appl. No.: |
11/596650 |
Filed: |
May 17, 2005 |
PCT Filed: |
May 17, 2005 |
PCT NO: |
PCT/US05/17080 |
371 Date: |
July 23, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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60571781 |
May 17, 2004 |
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60571843 |
May 17, 2004 |
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60571821 |
May 17, 2004 |
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Current U.S.
Class: |
606/34 ;
607/122 |
Current CPC
Class: |
A61B 5/283 20210101;
A61B 2018/00839 20130101; A61B 2018/00214 20130101; A61B 18/1492
20130101 |
Class at
Publication: |
606/034 ;
607/122 |
International
Class: |
A61B 18/12 20060101
A61B018/12 |
Claims
1. A computer-readable medium comprising computer-executable
instructions for controlling an electrophysiology system of the
type having a catheter with a plurality of electrically active
sites, the computer-executable instructions for performing acts of:
(a) providing at least one display area through which a user may
specify a set of the electrically active sites to be used in
sensing signals from a heart; (b) providing at least one display
area through which a user may specify a set of the electrically
active sites to be used in sending stimulation signals to the
heart; and (c) providing at least one display area through which a
user may specify a set of the electrically active sites to be used
in sending an ablation signal to the heart.
2. The computer-readable medium of claim 1, wherein the act (a)
comprises providing at least one display area having a graphical
representation of the plurality of electrically active sites.
3. The computer-readable medium of claim 2, wherein providing a
graphical presentation of each of the plurality of electrically
active sites comprises displaying on a computer display a control
associated with the plurality of electrically active sites.
4. The computer-readable medium of claim 1, wherein the act (a)
comprises providing at least one display area in response to a user
selection of a passive mapping mode.
5. The computer-readable medium of claim 1, wherein the act (c)
comprises providing at least one display area in response to the
user activating a control to place the electrophysiology system in
a ablation mode.
6. A computer-readable medium comprising computer-executable
instructions for controlling an electrophysiology system of the
type having a catheter with a plurality of electrically active
sites, the computer-executable instructions for performing acts of:
(a) for each of a plurality of sets of electrically active sites,
receiving from a user a specification of the electrically active
sites in the set; (b) receiving from the user a specification of a
specified order of the plurality of sets; and (c) for each of the
sets, successively in the specified order, controlling the
electrophysiology system to access the electrically active sites of
the set.
7. The computer-readable medium of claim 6, wherein the act (a)
comprises the acts of: (i) providing a graphical user interface
displaying a visual representation of the catheter and the
plurality of electrically active sites; and (ii) receiving user
input through the graphical user interface specifying selected ones
of the electrically active sites.
8. The computer-readable medium of claim 6, wherein the act (b)
comprises the acts of: (i) providing a graphical user interface
with a selection area associated with each of the plurality of
sets; (ii) receiving a plurality of successive user inputs
indicating a selection area; and (iii) deriving the specified order
of sets from an order in which the user accesses the specification
areas.
9. The computer-readable medium of claim 8, wherein the act (c)
comprises controlling the electrophysiology system to access the
electrically active sites of the set as each of the plurality of
successive user inputs is received.
10. The computer-readable medium of claim 8, wherein the act (c)
comprises the acts of: (i) recording the order of the plurality of
user inputs at a first time; and (ii) at a second time, later than
the first time, for each of the sets, successively in the recorded
order, controlling the electrophysiology system to access the
electrically active sites of the set.
11. The computer readable medium of 10, wherein the computer
executable instructions additionally perform the act of: (d)
capturing an ECG waveform in synchronization with successive
accesses for each of the sets of electrically active sites.
12. In an electrophysiology system having a catheter with a
plurality of electrically active sites and a computer having a
graphical user interface including a display and a user interface
selection device, a method of providing and selecting from a menu
on the display, comprising the acts of: (a) displaying on the
display a graphical representation of each of the plurality of
electrically active sites on the catheter; (b) receiving at least
one selection signal indicative of the user interface selection
device pointing at a graphical representation of a selected one of
the plurality of electrically active sites; and (c) controlling the
electrophysiology system to selectively access at least one of the
electrically active sites based on the at least one selection
signal.
13. The electrophysiology system of claim 12, wherein the act (c)
comprises controlling the electrophysiology system to selectively
apply a stimulus signal to at least one of the electrically active
sites based on the at least one selection signal.
14. The electrophysiology system of claim 12, wherein the act (c)
comprises controlling the electrophysiology system to selectively
apply a pace mapping signal.
15. The electrophysiology system of claim 13, wherein the act (c)
comprises controlling the electrophysiology system to selectively
apply an ablation signal.
16. The electrophysiology system of claim 13, wherein the method
additionally comprises the act of: (d) capturing data in
conjunction with the selective access of the at least one of the
electrically active sites.
17. The electrophysiology system of claim 12, wherein: the method
additionally comprises the act of (d) receiving a user input
specifying an operating mode of the system; and the act (c)
comprises selectively driving or receiving a signal through at
least one of the electrically active sites based on the user input
specifying an operating mode.
Description
RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. .sctn.
119(e) to U.S. Provisional Application Ser. No. 60/571,781,
entitled "MAPPING AND ABLATION METHOD AND APPARATUS FOR THE
TREATMENT OF IDIOPATHIC VENTRICULAR TACHYCARDIA ORIGINATING FROM
RVOT OR LVOT," filed on May 17, 2004, which is herein incorporated
by reference in its entirety, and U.S. Provisional Application Ser.
No. 60/571,843, entitled "MAPPING AND ABLATION METHOD AND APPARATUS
FOR THE TREATMENT OF IDIOPATHIC VENTRICULAR TACHYCARDIA," filed on
May 17, 2004, which is herein incorporated by reference in its
entirety. This application claims priority under 35 U.S.C. .sctn.
119(e) to U.S. Provisional Application Ser. No. 60/571,821,
entitled "METHOD AND APPARATUS FOR MAPPING AND/OR ABLATION OF
CARDIAC TISSUE," filed on May 17, 2004, which is herein
incorporated by reference in its entirety.
BACKGROUND OF INVENTION
[0002] 1. Field of Invention
[0003] The invention relates generally to medical devices for
performing mapping and ablation procedures. More particularly, the
invention relates to a system for mapping and/or ablating cardiac
walls.
[0004] 2. Discussion of Related Art
[0005] The human heart is a very complex organ, which relies on
both muscle contraction and electrical impulses to function
properly. The electrical impulses travel through the heart walls,
first through the atria and then the ventricles, causing the
corresponding muscle tissue in the atria and ventricles to
contract. Thus, the atria contract first, followed by the
ventricles. This order is essential for proper functioning of the
heart.
[0006] Over time, the electrical impulses traveling through the
heart can begin to travel in improper directions, thereby causing
the heart chambers to contract at improper times. Such a condition
is generally termed a cardiac arrhythmia, and can take many
different forms. When the chambers contract at improper times, the
amount of blood pumped by the heart decreases, which can result in
premature death of the person.
[0007] Techniques have been developed which are used to locate
cardiac regions responsible for the cardiac arrhythmia, and also to
disable the short-circuit function of these areas. According to
these techniques, electrical energy is applied to a portion of the
heart tissue to ablate that tissue and produce scars which
interrupt the reentrant conduction pathways or terminate the focal
initiation. The regions to be ablated are usually first determined
by endocardial mapping techniques. Mapping may be active or
passive. Active mapping, sometimes called "pace mapping," typically
involves percutaneously introducing a catheter having one or more
electrodes into the patient, passing the catheter through a blood
vessel (e.g. the femoral vein or artery) and into an endocardial
site (e.g., the atrium or ventricle of the heart), and deliberately
inducing an arrhythmia so that a continuous, simultaneous recording
can be made with a multichannel recorder at each of several
different endocardial positions. Passive mapping techniques
typically involve sensing electrical signals from the electrodes on
the catheter.
[0008] When an arrythormogenic focus or inappropriate circuit is
located, as indicated in the electrocardiogram recording, it is
marked by various imaging or localization means so that cardiac
arrhythmias emanating from that region can be blocked by ablating
tissue. An ablation catheter with one or more electrodes can then
transmit electrical energy to the tissue adjacent the electrode to
create a lesion in the tissue. One or more suitably positioned
lesions will typically create a region of necrotic tissue which
serves to disable the propagation of the errant impulse caused by
the arrythromogenic focus. Ablation is carried out by applying
energy to the catheter electrodes. The ablation energy can be, for
example, RF, DC, ultrasound, microwave, or laser radiation.
[0009] Atrial fibrillation together with atrial flutter are the
most common sustained arrhythmias found in clinical practice.
Current understanding is that atrial fibrillation is frequently
initiated by a focal trigger from the orifice of or within one of
the pulmonary veins. Though mapping and ablation of these triggers
appears to be curative in patients with paroxysmal atrial
fibrillation, there are a number of limitations to ablating focal
triggers via mapping and ablating the earliest site of activation
with a "point" radiofrequency lesion. One way to circumvent these
limitations is to determine precisely the point of earliest
activation. Once the point of earliest activation is identified, a
lesion can be generated to electrically isolate the trigger with a
lesion; firing from within those veins would then be eliminated or
unable to reach the body of the atrium, and thus could not trigger
atrial fibrillation.
[0010] Another method to treat focal arrhythmias is to create a
continuous, annular lesion around the ostia (i.e., the openings) of
either the veins or the arteries leading to or from the atria, thus
"corralling" the signals emanating from any points distal to the
annular lesion. Conventional techniques include applying multiple
point sources around the ostia in an effort to create such a
continuous lesion. Such a technique is relatively involved, and
requires significant skill and attention from the clinician
performing the procedures.
[0011] Another source of arrhythmias may be from reentrant circuits
in the myocardium itself. Such circuits may not necessarily be
associated with vessel ostia, but may be interrupted by means of
ablating tissue either within the circuit or circumscribing the
region of the circuit. It should be noted that a complete "fence"
around a circuit or tissue region is not always required in order
to block the propagation of the arrhythmia; in many cases simply
increasing the propagation path length for a signal may be
sufficient. Conventional means for establishing such lesion
"fences" include a multiplicity of point-by-point lesions, dragging
a single electrode across tissue while delivering energy, or
creating an enormous lesion intended to inactivate a substantive
volume of myocardial tissue.
[0012] U.S. Pat. No. 6,315,778 B1, entitled "Apparatus For Creating
A Continuous Annular Lesion," which is herein incorporated by
reference, discloses a medical device which is capable of ablating
a ring of tissue around the ostia of either veins or arteries
leading to or from the atria. The medical device includes a
protrusion that inserts into an ostium, thereby allowing electrodes
to contact tissue near the ostium.
[0013] In some instances, it is desirable to perform mapping and/or
ablation procedures on a cardiac wall (or other tissue) that is not
located near an ostium. In such a scenario, the lack of a
protrusion may help to allow electrodes of a device contact the
cardiac wall or other tissue. In other cases, mapping and/or
ablation may be desired at several locations around an ostium and
it would be helpful to be able to position electrodes without
concern for a protrusion that may hinder contact between electrodes
and the cardiac wall.
[0014] Another type of arrhythmia is Ventricular tachycardia.
Ventricular tachycardia (VT) usually arises in diseased myocardium.
However, VT can occur in the absence of structural heart disease,
or at least in hearts in which current diagnostic techniques fail
to identify any anatomic or functional abnormalities. These
arrhythmias have been termed "idiopathic VTs". The mechanisms
underlying idiopathic VT are varied and include reentry and
triggered activity due to delayed after depolarizations.
[0015] Idiopathic VTs that arise from the right to left ventricular
outflow tract (RVOT VT and LVOT VT) have been reported. Thus RVOT
VT and LVOT VT patients could be treated with RF ablation. However,
the success rate of ablation therapy for treatment of VT is
affected by many factors, such as the inability to induce
tachycardia to permit mapping, and the presence of deep, often
septal sites of origin that are resistant to RF ablation with
conventional ablation catheters, usually a 4-mm ablation catheter.
Treating VT in the area of the outflow track with ablation therapy
has been difficult.
SUMMARY OF INVENTION
[0016] Embodiments of the present invention encompass apparatus and
methods for mapping electrical activity within the heart.
Embodiments of the present invention also encompass methods and
apparatus for creating lesions in the heart tissue (ablating) to
create a region of necrotic tissue which serves to disable the
propagation of errant electrical impulses caused by an arrhythmia.
The apparatus and methods described herein also may be used for
mapping and ablating of tissue other than heart tissue.
[0017] In one aspect, the invention relates to a computer-readable
medium comprising computer-executable instructions for controlling
an electrophysiology system of the type having a catheter with a
plurality of electrically active sites. The computer-executable
instructions performing acts of providing at least one display area
through which a user may specify a set of the electrically active
sites to be used in sensing signals from the heart; providing at
least one display area through which a user may specify a set of
the electrically active sites to be used in sending stimulation
signals to the heart; and providing at least one display area
through which a user may specify a set of the electrically active
sites to be used in sending an ablation signal to the heart.
[0018] In another aspect, the invention relates to a
computer-readable medium comprising computer-executable
instructions for controlling an electrophysiology system of the
type having a catheter with a plurality of electrically active
sites. The computer-executable instructions for performing acts of,
for each of a plurality of sets of electrically active sites,
receiving from a user a specification of the electrically active
sites in the set; and receiving from the user a specification of a
specified order of the plurality of sets; and for each of the sets,
successively in the specified order, controlling the
electrophysiology system to access the electrically active sites of
the set.
[0019] In a further aspect, the invention relates to a method of
providing and selecting from a menu on a display in an
electrophysiology system having a catheter with a plurality of
electrically active sites and a computer having a graphical user
interface, the method involves: displaying on the display a
graphical representation of each of the plurality of electrically
active sites on the catheter; receiving at least one selection
signal indicative of the user interface selection device pointing
at a graphical representation of a selected one of the plurality of
electrically active sites; and controlling the electrophysiology
system to selectively access at least one of the electrically
active sites based on the at least one selection signal.
BRIEF DESCRIPTION OF DRAWINGS
[0020] The accompanying drawings are not intended to be drawn to
scale. In the drawings, like components that are illustrated in
various figures are represented by a like numeral. For purposes of
clarity, not every component may be labeled in every drawing. In
the drawings:
[0021] FIG. 1 illustrates an overview of an electrophysiology
system in accordance with one embodiment of the present
invention;
[0022] FIG. 2 illustrates a braided conductive member in an
undeployed state that may be used in one embodiment of the
invention;
[0023] FIG. 3 illustrates a braided conductive member in a
partially expanded state that may be used in one embodiment of the
invention;
[0024] FIG. 4 illustrates a braided conductive member in an
inverted state that may be used in one embodiment of the
invention;
[0025] FIG. 5 illustrates a braided conductive member in an
inverted state where a distal end of the braided conductive member
does not protrude distally from the inverted braided conductive
member that may be used in one embodiment of the invention;
[0026] FIG. 6 illustrates a braided conductive member including
support elements that may be used in one embodiment of the
invention;
[0027] FIG. 7 illustrates a braided conductive member that may be
used in another embodiment of the invention;
[0028] FIG. 8 illustrates an alternate embodiment of the braided
conductive member that may be used in another embodiment of the
invention;
[0029] FIG. 9 illustrates the use of irrigation that may be used in
one embodiment of the invention;
[0030] FIG. 10 illustrates the use of irrigation that may be used
in another embodiment of the invention;
[0031] FIG. 10A is an enlarged cross-sectional view of a filament
used in the braided conductive member illustrated in FIG. 10;
[0032] FIG. 11 illustrates one embodiment of a method of using a
catheter and the braided conductive member;
[0033] FIG. 12 is a sketch showing the electrophysiology system of
FIG. 1 in greater detail;
[0034] FIGS. 13A and 13B are sketches of graphical user interfaces
in embodiments of the electrophysiology system of FIG. 12; and
[0035] FIG. 14 is a flow chart of a method of operation of the
electrophysiology system of FIG. 12.
DETAILED DESCRIPTION
[0036] This invention is not limited in its application to the
details of construction and the arrangement of components and acts
set forth in the following description or illustrated in the
drawings. The invention is capable of other embodiments and of
being practiced or of being carried out in various ways. Also, the
phraseology and terminology used herein is for the purpose of
description and should not be regarded as limiting. The use of
"including," "comprising," or "having," "containing", "involving",
and variations thereof herein, is meant to encompass the items
listed thereafter and equivalents thereof as well as additional
items.
System Overview
[0037] Reference is now made to FIG. 1, which illustrates an
overview of an electrophysiology system, such as may be used for
mapping and/or ablation to detect and treat cardiac arrhythmia. The
system includes a catheter 10 having a shaft portion 12, a control
handle 14, a connector portion 16, and a braided conductive member
28. A controller 8 is connected to connector portion 16 via cable
6. Ablation energy generator 4 may be connected to controller 8 via
cable 3. A recording device 2 may be connected to controller 8 via
cable 1. When used in an ablation application, controller 8 is used
to control ablation energy provided to catheter 10 by ablation
energy generator 4. When used in a mapping application, controller
8 is used to process signals coming from catheter 10 and to provide
these signals to recording device 2. Although illustrated as
separate devices, recording device 2, ablation energy generator 4,
and controller 8 could be incorporated into a single device or two
devices.
[0038] In this description, various aspects and features of
exemplary embodiments of the present invention will be described.
These aspects and features are discussed separately for clarity.
One skilled in the art will appreciate that the features may be
selectively combined in a device depending upon the particular
application. Furthermore, any of the various features may be
incorporated in a system and associated method of use for either
mapping and/or ablation procedures.
Catheter Overview
[0039] Reference is now made to FIGS. 2-5, which illustrate a
catheter that may be used in the electrophysiology system of FIG.
1. Embodiments of the present invention generally include a
catheter and methods of its use for mapping and ablation in
electrophysiology procedures.
[0040] FIG. 2 illustrates braided conductive member 28 in an
unexpanded state. In this embodiment, the unexpanded state of the
braided conductive member is an undeployed configuration. Braided
conductive member 28 is, in one embodiment of the invention, a
plurality of interlaced, electrically conductive filaments 34 which
are attached at a distal end 18 with a cap 24 and also at a
proximal end 19 with an anchoring element 32. Of course any
suitable element or method may be used to attach or anchor
filaments 34.
[0041] FIG. 3 illustrates braided conductive member 28 in a
partially expanded state. Each of FIGS. 2 and 3 show a state in
which braided conductive member 28 is completely everted.
[0042] FIG. 4 illustrates braided conductive member 28 in a first
deployed configuration option which may be used to locate braided
conductive member 28 at an ostium. In FIG. 4, distal end 18 of
braided conductive member 28 is partially inverted. The terms
"partially invert" and "partially inverted", for purposes herein,
refer to a configuration in which portions of filaments are
retracted within the braided conductive member such that they are
at least partially surrounded by other portions of filaments. A
tip, or other portions of the braided conductive member may
protrude distally from any distally-facing surface of the braided
conductive member when the braided conductive member is partially
inverted.
[0043] FIG. 5 illustrates braided conductive member 28 in a second
deployed configuration option which may be used to effect contact
between an annular surface of braided conductive member 28 and a
cardiac wall (see, for example, FIG. 11) other cardiac tissue, or
other target tissue. In FIG. 5, the distal tip of braided
conductive member 28 is inverted. The terms "invert" or "inverted",
for purposes herein, refer to a configuration in which the distal
tip or distal end of the braided conductive member is retracted
such that the distal tip does not protrude distally from a
distally-facing surface of the braided conductive member. For
purposes herein, the terms "evert" or "everted" refer to a
configuration in which the distal tip or distal end of the braided
conductive member protrudes distally from any distally-facing
annular surface that is present. An everted configuration does not,
however, require that a distally-facing annular surface be present.
In some embodiments, such as the embodiment illustrated in FIG. 2,
the braided conductive member is fully elongated in an everted
configuration. The term "completely everted", when referring to a
distal region of a braided conductive member, refers to a
configuration in which no portion of the distal region of the
braided conductive member is inverted within itself.
[0044] A braided conductive member adjustment element, such as a
cable 22, is attached to distal end 18 of braided conductive member
28. Cable 22 may extend through a lumen (not shown) in shaft
portion 12 and through the interior of braided conductive member
28. Cable 22 may be attached to distal end 18 of braided conductive
member 28 using cap 24, an anchor band, or any suitable attachment
or anchoring element or method known in the art. At the control
handle end, cable 22 may be attached to a control element, such as
a slide actuator for example, that allows a user to retract and
advance cable 22. It should be noted that cable 22 is a separate
element from cables 1, 3 and 6. Of course, braided conductive
member adjustment element need not be a cable as any suitable
element for adjusting the braided conductive member may be used.
For example, a sheath may be used to push the braided conductive
member over the distal tip of the braided conductive member to
invert braided conductive member 28.
[0045] In operation, moving cable 22 in the proximal direction
causes braided conductive member 28 to compress longitudinally
and/or to expand radially, as shown in FIG. 3. Further proximal
movement of cable 22 causes a portion of braided conductive member
28 to invert as shown in FIG. 4. Even further proximal movement of
cable 22 may retract distal end 18 such that distal end 18 is
encircled by a portion of braided conductive member 28. In some
embodiments, distal end 18 may be surrounded or partially
surrounded by a portion of braided conductive member 28 that does
not form a circle.
[0046] In some embodiments, a certain amount of movement of cable
22 in the proximal direction may occur without user actuation due
to the bias of the braided conductive member 28. For example,
braided conductive member 28 may be longitudinally extended beyond
a relaxed state by radially compressing braided conductive member
28 with a sheath 33 (see FIG. 2). Upon retraction of sheath 33,
braided conductive member 28 may radially expand a certain amount
due to its filament winding structure, or due to elastic or spring
elements attached to the filaments. In further embodiments, cable
22 may be used to urge braided conductive member 28 back into a
longitudinally extended state by pushing on cap 24 or other distal
attachment portion.
[0047] By retracting distal end 18 of braided conductive member 28
at least a certain distance in the proximal direction, a braided
conductive member annular surface 30 may be formed in a plane that
is substantially perpendicular to a distal end 26 of shaft portion
12, as illustrated in FIG. 4. Retracting distal end 18 further
removes the projection of distal end 18 beyond annular surface 30,
as illustrated in FIG. 5, which may allow annular surface 30 to be
placed in contact with a cardiac wall or other cardiac tissue. If
braided conductive member 28 is only partially inverted and distal
end 18 projects beyond annular surface 30 in the distal direction,
it may hinder efforts to contact cardiac tissue with the annular
surface. In some embodiments, however, it may be desirable to
maintain a portion of distal end 18 projecting from braided
conductive member 28 so that braided conductive member 28 may be
positioned relative to an ostium by inserting distal end 18 into
the ostium. In some embodiments, the annular surface may be
arranged such that it is contactable to a substantially flat area
of tissue that has no ostia, even though an element may protrude
distally from the annular surface. For example, a highly flexible
element, such as a touch sensor, may protrude distally from the
inverted braided conductive member and the annular surface would
still be arranged such that it is contactable to a substantially
flat area of tissue that has no ostia. The touch sensor may be a
bend sensor that is positioned on the distal tip of the braided
conductive member and protrudes slightly from the distally-facing
surface when the braided conductive member is put into a deployed
configuration. The bend sensor bends upon encountering a tissue
wall and signals the controller that it has bent. The flexibility
of the bend sensor allows the braided conductive member to contact
the wall.
[0048] For purposes herein, a "surface" of braided conductive
member 28 refers to a plurality of interlaced conductive elements,
such as filaments or wires, even though the interlaced elements may
not fully occupy the space considered to be the surface. In some
embodiments, wires or other conductive elements may be attached to
or embedded in a flexible support material such that a solid
surface is present.
[0049] The annular surface formed by inverting the braided
conductive member 28 may have electrodes spaced around the entire
annular surface. In other embodiments, electrodes may be positioned
only on a portion or portions of the ring-shaped surface.
[0050] As illustrated in FIGS. 2-5, a sheath 33 may be provided.
Sheath 33 serves to protect shaft portion 12 and braided conductive
member 28 during manipulation through the patient's vasculature. In
addition, sheath 33 may shield braided conductive member 28 from
the patient's tissue in the event ablation energy is prematurely
delivered to the braided conductive member 28.
[0051] Sheath 33 may be advanced and retracted over shaft portion
12 in any suitable manner. Control handle 14 may be used to effect
the advancement or retraction of sheath 33. U.S. Pat. Nos.
5,383,852, 5,462,527, and 5,611,777, which are herein incorporated
by reference in their entireties, illustrate examples of control
handles that can control sheath 33. As described in these patents,
control handle 14 may include a slide actuator which is axially
displaceable relative to the handle. The slide actuator may be
connected to sheath 33 to retract sheath 33 to expose braided
conductive member 28 once the distal end of the catheter has been
positioned within the heart or other target location.
[0052] Braided conductive member 28 may be shape or biased such
that when sheath 33 is retracted, braided conductive member 28
expands slightly in the radial direction. In other embodiments,
braided conductive member 28 may maintain its longitudinally
extended shape until cable 22 or other adjustment element is pulled
in the proximal direction to longitudinally compress braided
conductive member 28. In still other embodiments, braided
conductive member 28 may maintain a radial size similar to its
relaxed state radial size when distal tip 18 is moved proximally,
or even when braided conductive member 28 is inverted.
[0053] Braided conductive member 28 is, in one embodiment of the
invention, a plurality of interlaced, electrically conductive
filaments 34. In some embodiments, braided conductive member 28 is
a wire mesh. The filaments 34 are preferably formed of metallic
elements having relatively small cross sectional diameters, such
that the filaments are flexible and the braided conductive member
can be expanded radially outwardly. In one embodiment, the
filaments may be round in cross-section, having a dimension on the
order of about 0.001-0.030 inches in diameter. Alternatively, the
filaments may have flat sides in cross-section, with thicknesses on
the order of about 0.001-0.030 inches, and widths on the order of
about 0.001-0.030 inches. The filaments may be formed of
nitinol-type wire or other shaped memory alloys. Alternatively, the
filaments may include non-metallic elements woven with metallic
elements, with the non-metallic elements providing support to
and/or separation of the metallic elements. A multiplicity of
individual filaments 34 may be provided in braided conductive
member 28, for example three hundred or more filaments. Instead of
a multiplicity or plurality of filaments, a smaller number of
filaments, or even only one continuous filament may be arranged to
form braided conductive member 28. For purposes herein, the terms
"filaments" or "plurality of filaments" may refer to one continuous
filament that is interlaced with itself to form a braided
conductive member.
[0054] Each of the filaments 34 may be electrically isolated from
each other by an insulation coating. This insulation coating may
be, for example, a polyamide type material. In one manner of
forming an electrode, a portion of the insulation on the filaments
forming an outer circumferential surface of braided conductive
member 28 is removed. This arrangement allows each of the filaments
34 to form an isolated electrode, not in electrical contact with
any other filament, that may be used for mapping and ablation. In
some embodiments, an electrode may contact a coated section of
another filament. Alternatively, specific electrodes may be
permitted to contact each other to form a preselected grouping.
Methods of removing insulation from filaments 34 are disclosed in
PCT Publication No. WO 02/087437, which is herein incorporated by
reference in its entirety. The insulation may also be removed in a
preferential manner so that a particular portion of the
circumferential surface of a filament 34 is exposed. In this
manner, when braided conductive member 28 is radially expanded, the
stripped portions of filaments may preferentially face an intended
direction of mapping or ablation.
[0055] Further, in some embodiments some of filaments 34 may be
used for mapping or electrical measurement, while others of
filaments 34 may be used for ablation. The mapping and ablation
filaments may be activated independently or may be activated
concurrently. One application of dedicating some filaments for
mapping and others for ablation is using a single braided
conductive member 28 to both form a lesion and measure the quality
of the lesion. Such an arrangement can avoid a change of catheters
during a medical procedure. Temperature sensors (not shown) also
may be included on catheter shaft 12 or braided conductive member
28.
[0056] A wire (not shown) may run from each of the filaments 34 to
connector portion 16 via conductors (not shown). A multiplexer or
switch box (see, for example, switch matrix 1230, FIG. 12) may be
connected to the conductors so that each filament 34 may be
controlled individually. This function may be incorporated into
controller 8. In some embodiments, a number of filaments 34 may be
grouped together for mapping and ablation. Alternatively, each
individual filament 34 may be used as a separate mapping channel
for mapping individual electrical activity at a single point. Using
a switch box or multiplexer to configure the signals being received
by filaments 34 or ablation energy sent to filaments 34 results in
a large number of possible combinations of filaments for detecting
electrical activity during mapping procedures and for applying
energy during an ablation procedure.
[0057] Catheter 10 may also have a reference electrode (not shown)
mounted on shaft 12 so that the reference electrode is located
outside the heart during unipolar mapping operations.
[0058] Individual control of the electrical signals received from
filaments 34 allows catheter 10 to be used for bipolar
(differential or between filament) type mapping as well as unipolar
(one filament with respect to a reference electrode) type
mapping.
[0059] Catheter 10 may be a steerable device, in some embodiments,
in that the distal end 26 may be deflected by an actuator contained
within control handle 14. Control handle 14 may include a rotatable
thumb wheel which can be used by a user to deflect distal end 26 of
the catheter. The thumb wheel (or any other suitable actuating
device) is connected to one or more pull wires (not shown) which
extend through shaft portion 12 and connect to distal end 18 of the
catheter at an off-axis location, whereby tension applied to one or
more of the pull wires causes the distal portion of the catheter to
curve in a predetermined direction or directions. U.S. Pat. Nos.
5,383,852, 5,462,527, and 5,611,777 illustrate various embodiments
of control handle 14 that may be used for steering catheter 10.
[0060] In some embodiments, a proximal portion of braided
conductive member 28 includes support elements to aid in
maintaining the shape and/or structural integrity of portions of
braided conductive member 28 when distal end 18 is moved in the
proximal direction. For example, support elements may include
support filaments 34' that are stronger, thicker or more rigid at
their proximal ends than at their distal ends, as illustrated in
FIG. 6. In other embodiments, splines 35 or other non-filament
elements may be included, such as by interlacing support elements
among filaments 34, as illustrated in FIG. 7. In still further
embodiments, support elements which are not interlaced with
filaments 34 may be included. In some embodiments, support elements
attach to a proximal anchoring element 32 at a first end and to cap
24 or filaments 34 at a second end.
[0061] Referring to FIG. 7, an embodiment of the invention having a
longitudinally asymmetrically shaped braided conductive member 28
is illustrated. In this embodiment, a maximum diameter 36 of
braided conductive member 28 is located closer to distal end 18
than to proximal anchoring element 32. In one embodiment, maximum
diameter 36 is longitudinally located more than two-thirds of the
way from the proximal anchoring location to the distal attachment
location. As cable 22 is drawn in the proximal direction to move
cap 24, splines 35 support the more proximal region of braided
conductive member 28.
[0062] Reference is now made to FIG. 8 which illustrates another
shape of braided conductive member 28. As described above regarding
various embodiments of the invention, braided conductive member 28
may be generally radially symmetrical. However, certain anatomical
structures may have complex three-dimensional shapes that are not
easily approximated by a geometrically symmetrical mapping or
ablation structure. To successfully contact these types of
anatomical structures, braided conductive member 28 can be
"preformed" to a close approximation of that anatomy, and yet still
be flexible enough to adapt to variations found in specific
patients. Alternatively, braided conductive member 28 can be of
sufficient strength (as by choice of materials, configuration,
etc.) to force the tissue to conform to variations found in
specific patients. For example, FIG. 8 illustrates braided
conductive member 28 disposed about shaft 12 in an off-center or
non-concentric manner such that braided conductive member 28 is
radially asymmetrically-shaped. In addition, braided conductive
member 28 may also be constructed so that the annular surface of
the braided conductive member in its expanded configuration is a
non-circular surface so as to improve tissue contact. FIG. 8
illustrates an example of this type of configuration where the
braided conductive member 28 is constructed and arranged to be
non-concentric with respect to a longitudinal axis of braided
conductive member 28 and also, in its expanded configuration, to
have an asymmetric shape. In some embodiments, the asymmetric
expanded configurations and the eccentricity of braided conductive
member 28 with respect to the longitudinal axis can be produced by
providing additional structural supports in braided conductive
member 28, for example, by adding nitinol wire, ribbon wire,
splines, and so on. Other suitable methods of creating the
eccentric and/or asymmetric shape include: varying the winding
pitch; varying individual filament size and/or placement; deforming
selective filaments in braided conductive member 28; and any other
suitable method known to those skilled in the art.
[0063] An asymmetrically-shaped braided conductive member may allow
for the formation of a ring-shaped surface that is disposed at an
angle to general longitudinal direction of the braided member
and/or the distal end of the catheter. The angled surface may
permit better contact with certain tissue areas. In still other
embodiments, inverting the braided conductive member may form a
non-planar surface. For example, differing filament diameters may
allow for the formation of a ring-shaped surface which includes a
section that is substantially perpendicular to the catheter and a
section that is disposed at an angle to the catheter. The angle of
the surface relative to the catheter may change continuously across
the surface in still other embodiments.
[0064] In some embodiments of the present invention, catheter 10
may be coated with a number of coatings that enhance the operating
properties of braided conductive member 28. The coatings may be
applied by any of a number of techniques and the coatings may
include a wide range of polymers and other materials.
[0065] Braided conductive member 28 may be coated to reduce its
coefficient of friction, thus reducing the possibility of thrombi
adhesion to the braided conductive member as well as the
possibility of vascular or atrial damage. These coatings can be
combined with insulation (if present) on the filaments that make up
braided conductive member 28. These coatings may be included in the
insulation itself, or the coatings may be applied over the
insulation layer.
[0066] Braided conductive member 28 also may be coated to increase
or decrease its thermal conduction, which can improve the safety or
efficacy of the braided conductive member 28. This change in
thermal conduction may be achieved by incorporating thermally
conductive elements or thermally insulating elements into the
electrical insulation of the filaments that make up braided
conductive member 28, or by adding a coating to the assembly.
Polymer mixing, IBAD, or similar technology could be used to add
Ag, Pt, Pd, Au, Ir, Cobalt, and others into the insulation or to
coat braided conductive member 28.
[0067] In some embodiments, radioopaque coatings or markers may be
used to provide a reference point for orientation of braided
conductive member 28 when viewed during fluoroscopic imaging. The
materials that provide radiopacity include, for example, Au, Pt,
Ir, and others known to those skilled in the art. These materials
may be incorporated and used as coatings as described above.
[0068] Antithrombogenic coatings, such as heparin and BH, can also
be applied to braided conductive member 28 to reduce
thrombogenicity to prevent blood aggregation on braided conductive
member 28. These coatings can be applied by dipping or spraying,
for example.
[0069] As noted above, the filament 34 of braided conductive member
28 may be constructed of metal wire materials. These materials may
be, for example, MP35N, nitinol, or stainless steel. Filaments 34
may also be composites of these materials in combination with a
core of another material such as silver or platinum. The
combination of a highly conductive electrical core material with
another material forming the shell of the wire allows the
mechanical properties of the shell material to be combined with the
electrical conductivity of the core material to achieve better
and/or selectable performance. The choice and percentage of core
material used in combination with the choice and percentage of
shell material used can be selected based on the desired
performance characteristics and mechanical/electrical properties
desired for a particular application.
[0070] There may be times during ablation or mapping procedures
when catheter 10 passes through difficult or tortuous vasculature.
During these times, it may be helpful to have a guiding sheath (not
shown) through which to pass catheter 10 so as to allow easier
passage through the patient's vasculature.
Irrigation
[0071] It is known that for a given electrode side and tissue
contact area, the size of a lesion created by radiofrequency (RF)
energy is a function of the RF power level and the exposure time.
At higher powers, however, the exposure time can be limited by an
increase in impedance that occurs when the temperature at the
electrode-tissue interface approaches 100.degree. C. One way of
maintaining the temperature less than or equal to this limit is to
irrigate the ablation electrode with saline to provide convective
cooling so as to control the electrode-tissue interface temperature
and thereby prevent an increase in impedance. Accordingly,
irrigation of braided conductive member 28 and the tissue site at
which a lesion is to be created can be provided in the present
invention. FIG. 9 illustrates the use of an irrigation manifold
within braided conductive member 28. An irrigation manifold 100 is
disposed along shaft 12 inside braided conductive member 28.
Irrigation manifold 100 may be one or more polyimide tubes. Within
braided conductive member 28, the irrigation manifold splits into a
number of smaller tubes 102 that are woven into braided conductive
member 28 along a respective filament 34. A series of holes 104 may
be provided in each of the tubes 102. These holes can be oriented
in any number of ways to target a specific site or portion of
braided conductive member 28 for irrigation. Irrigation manifold
100 runs through catheter shaft 12 and may be connected to an
irrigation delivery device outside the patient used to inject an
irrigation fluid, such as saline, for example, such as during an
ablation procedure.
[0072] The irrigation system can also be used to deliver a contrast
fluid for verifying location or changes in vessel diameter. For
example, a contrast medium may be perfused prior to ablation and
then after an ablation procedure to verify that there have been no
changes in the blood vessel diameter. The contrast medium can also
be used during mapping procedures to verify placement of braided
conductive member 28. In either ablation or mapping procedures,
antithrombogenic fluids, such as heparin can also be perfused to
reduce thrombogenicity. FIG. 10 illustrates another way of
providing perfusion/irrigation in catheter 10. As illustrated in
FIG. 10, the filaments 34 that comprise braided conductive member
28 may be composed of a composite wire 110. The composite wire 110
includes a lumen 114 containing an electrically conductive wire 112
that is used for delivering ablation energy in an ablation
procedure or for detecting electrical activity during a mapping
procedure. Composite wire 110 also contains a perfusion lumen 116.
Perfusion lumen 116 is used to deliver irrigation fluid or a
contrast fluid as described in connection with FIG. 9. Once braided
conductive member 28 has been constructed with composite wire 110,
the insulation 118 surrounding wire filament 112 can be stripped
away to form an electrode surface. Holes can then be provided in
perfusion lumen 116 to then allow perfusion at targeted sites along
the electrode surface. As with the embodiment illustrated in FIG.
9, the perfusion lumens can be connected together to form a
manifold which manifold can then be connected to, for example,
perfusion tube 120 and connected to a fluid delivery device.
Methods of Use
[0073] Reference is now made to FIG. 11 which illustrates how a
catheter according to certain embodiments of the present invention
may be used in endocardial applications.
[0074] In an endocardial procedure, shaft portion 12 is introduced
into a patient's heart 150. Appropriate imaging guidance (direct
visual assessment, camera port, fluoroscopy, echocardiographic,
magnetic resonance, etc.) can be used. FIG. 11 in particular
illustrates shaft portion 12 being placed in the left atrium of the
patient's heart, though a catheter using a braided conductive
member 28 is well suited for mapping and ablating in other
structures, such as ventricles, particularly near the ventricular
outflow tract. Once shaft portion 12 reaches the patient's left
atrium, sheath 33 may be retracted and braided conductive member 28
may be inverted to its deployed state, where, in the illustrated
embodiment, braided conductive member 28 forms a cone-type shape
including a distally-facing, ring-shaped surface. External pressure
may be applied along shaft portion 12 to achieve the desired level
of contact between braided conductive member 28 and the cardiac
tissue. In one embodiment, mapping of electrical impulses may be
achieved with braided conductive member 28. In another embodiment,
energy is applied to the cardiac tissue in contact with braided
conductive member 28 to create an annular lesion. The energy used
may be RF (radiofrequency), DC, microwave, ultrasonic, cryothermal,
optical, etc.
[0075] In some embodiments, the braided conductive member may be
configured such that it forms a distally-facing, ring-shaped
surface before the braided conductive member is introduced to the
heart.
Controller
[0076] FIG. 12 shows further details of an embodiment of the
controller 8 of FIG. 1. In this embodiment, the controller includes
a computer 1210. Computer 1210 has a display 1216 through which
computer 1210 may provide a graphical user interface through which
a user may input commands or receive information gathered by the
electrophysiology system. For example, the user interface allows a
user to operate the system to apply electrical signals to braided
conductive member 28 during a method of diagnosing or treating an
arrhythmia.
[0077] Computer 1210 may be used in the performance of procedures
and data processing operations, such as are described in copending
patent applications, such as an application entitled METHODS FOR
PROCESSING ELECTROCARDIAC SIGNALS HAVING SUPERIMPOSED COMPLEXES
published as US 2002-0091330 A1 on Jul. 11, 2002; an application
entitled SOFTWARE CONTROLLED ELECTROPHYSIOLOGY DATA MANAGEMENT
published as US 2002-0065459 A1 on May 30, 2002; an application
entitled MULTI-COLOR DISPLAY OF CLOSELY PROXIMATE AND OVERLAPPING
CARDIAC SIGNALS, published as WO 2005/008418 A2 on Jan. 27, 2005,
all of which are hereby incorporated by reference.
[0078] Computer 1210 may be a standard computer, such as is widely
used in business settings, with a standard operating system that
executes desired application programs. Such a computer may be
equipped with data acquisition and control boards, as are known in
the art, to receive data and control other components of a system.
Alternatively, computer 1210 may be a custom designed computer
having a form factor and other characteristics customized for use
in an electrophysiology laboratory. Such a computer may contain one
or more general purpose or special purpose processors that may be
integrated with data acquisition and control hardware. However, the
specific construction of computer 1210 is not a limitation of the
invention.
[0079] Computer 1210 includes user input devices which may include
a touch pad, a touch screen, a pointing wheel, buttons and/or other
devices. In the illustrated embodiment, computer 1210 includes a
keyboard 1212 and a mouse 1214 that serve as user input devices.
Mouse 1214 may serve as a user interface selection device that
works in cooperation with a graphical user interface presented on
display 1216. A user may use known motions, such as moving mouse
1214 to place a cursor over an object appearing as part of the
graphical user interface and "clicking" on the object to invoke a
function associated with that object.
[0080] Computer 1210 typically includes at least some form of
computer readable media. Computer readable media can be any
available media that can be accessed by Computer 1210. By way of
example, and not limitation, computer readable media may comprise
computer storage media and communication media. Computer storage
media includes volatile and nonvolatile, removable and
non-removable media implemented in any method or technology for
storage of information such as computer readable instructions, data
structures, program modules or other data. Computer storage media
includes, but is not limited to, RAM, ROM, EEPROM, flash memory or
other memory technology, CD-ROM, digital versatile disks (DVD) or
other optical storage, magnetic cassettes, magnetic tape, magnetic
disk storage or other magnetic storage devices, or any other medium
which can be used to store the desired information and which can
accessed by Computer 1210. Communication media typically embodies
computer readable instructions, data structures, program modules or
other data in a modulated data signal such as a carrier wave or
other transport mechanism and includes any information delivery
media. Combinations of the any of the above should also be included
within the scope of computer readable media.
[0081] Computer-readable media may contain computer-executable
instructions that cause computer 1210 to generate signals that
control operation of the electrophysiology system or to gather and
process data from the system. Computer-executable instructions may
be in multiple forms, such as program modules, executed by one or
more computers or other devices. Generally, program modules include
routines, programs, objects, components, data structures, etc. that
perform particular tasks or implement particular abstract data
types. Typically the functionality of the program modules may be
combined or distributed as desired in various embodiments.
[0082] The computer-executable instructions may program computer
1210 to perform multiple functions as are known in the art or are
as described in greater detail herein. Computer 1210 may, for
example, issue control signals to configure braided conductive
member 28 to perform specific operations. Braided conductive member
28 includes multiple electrically active sites. In use, the
electrically active sites may be used to apply electrical signals
or measure signals from a heart or other structure in contact with
a surface of braided conductive member 28. Such electrically active
sites may, for example, be formed by stripping insulation from
conductive filaments forming braided conductive member 28. Braided
conductive member 28 may be configured by connecting selected ones
of the conducting filaments 34 to specific components of the
electrophysiology system. Switch matrix 1230 allows these
connections to be made under control of computer 1210.
[0083] In the illustrated embodiment, the electrophysiology system
includes an RF generator 124 that may be used to generate an RF
signal for ablation. RF generator 124 may be connected through
switch matrix 1230 to cable 6, which contains wires that connect to
the electrically conductive filaments 34. Switch matrix 1230 may be
controlled by computer 1210 to connect RF generator 124 to any one
or more of the electrically conductive filaments 34. In this
embodiment, RF controller 1242 is used to extract information from
connections made through catheter 10. For example, controller 1242
may detect impedances and temperates at the catheter to monitor an
ablation process. RF controller 1242 may also be used to control
the power level applied. For example, controller 1242 may provide a
lower power while the system of FIG. 12 is configured for pace
mapping and a higher power when the system is configured for
ablation.
[0084] Similarly, recording device 2 is coupled through switch
matrix 1230 to cable 6. In this way, computer-executable
instructions associated with computer 1210 may configure, at any
time, each of the electrically active sites to provide a stimulus
signal to apply an ablation signal, to take a measurement or to
perform no function.
[0085] Computer 1210 may also receive inputs from other components
of the electrophysiology system. For example, computer 1210 is
shown connected to a navigation system 1250. Navigation system 1250
may be a navigation system as is known in the art. Such a system
may output values representing the position of a catheter during a
mapping or ablation procedure. Computer 1210 may also receive
inputs from ECG system 1260. Such a system may be used in a pace
mapping procedure. During pace mapping, stimulus signals provided
to the heart through catheter 10 may be detected externally through
ECG system 1260. Computer 1210, may use this information to
determine whether the applied stimulus triggered a response that is
similar to the ECG measured for a patient during an arrhythmia
episode.
[0086] Computer 1210 provides a user interface on display 1216 that
may facilitate the use of electrophysiology system as pictured in
FIG. 12, particularly one that includes a catheter that can be
configured. In particular, braided conductive member 28 provides a
substrate on which multiple electrically active sites are mounted.
In use, the catheter is configured by selectively accessing groups
of the electrically active sites.
[0087] FIGS. 13A and 13B illustrate an embodiment in which a
graphical user interfaced is used in configuring a catheter. The
graphical user interface allows the electrically active sites to be
accessed in one of multiple ways. Each electrically active site may
be accessed individually. Alternatively, the electrically active
sites may be formed into groups. The groups may then be accessed
individually or may be accessed according to a pattern specified by
a user.
[0088] Turning to FIG. 13A, a window 1310 such as may appear on
display 1216 is illustrated. Window 1310 includes a menu bar 1330
that allows a user to specify the operating mode of the
electrophysiology system in which the site groupings specified are
used. In this example, the electrophysiology system may be used for
passive mapping, pace mapping or ablation. Accordingly, menu bar
1330 includes a control 1332, allowing the user to specify a
configuration for passive mapping procedures. Window 1310 likewise
includes controls 1334 and 1336 which allow the user to specify a
site group for pace mapping procedures and ablation procedures,
respectively. Window 1310 includes graphical component 1320
representing the catheter. The individual electrically active sites
are indicated by controls such as those indicated at 1322A and
1322B. In this embodiment, each electrically active site has a
corresponding control displayed in window 1310.
[0089] In the mode displayed in FIG. 13A, a user may access an
electrically active site individually. Any suitable method may be
used to receive user input indicating a selection of a specific
electrically active site. In the illustrated embodiment,
traditional "point and click" commands are used. A user may
manipulate mouse 1214 or other user input selection device attached
to computer 1210 to position a curser 1340 over the control
indicating the selective electrically active site. By "clicking"
the mouse or otherwise indicating a selection, the user may specify
that the electrically active site corresponding to the control be
accessed.
[0090] Such a user interface may be implemented using programming
techniques as are known in the art. For example, traditional
software systems with graphical user interfaces associate program
elements with controls appearing on a computer display. When a user
selects a specific control, the software associated with the
control is executed. In the example of FIG. 13A, selecting a
control representing an electrically active site may, for example,
execute software on computer 1210 that sends a signal to switch
matrix 1230 to connect that electrically active site to RF
generator 1240. However, the specific action taken in response to a
user selection of an electrically active site may depend on the
operating mode selected. For example, when the user has selected a
passive mapping operating mode through menu choice 1332, the
software executed in response to this selection may connect the
selectively active site to recording device 2.
[0091] FIG. 13B shows an alternative user interface that may be
used to access electrically active sites in groups. FIG. 13B shows
a window 1350 that may, for example, appear on display 1216 as part
of a graphical user interface presented to an operator of the
electrophysiology system of FIG. 12. Window 1350 includes multiple
controls, each representing a group of electrically active sites on
a catheter that is used in connection with the electrophysiology
system. In the illustrated example controls 1351, 1352 and 1353 are
shown, representing three subgroups of electrically active sites
that have been defined. However, the number of groups is not a
limitation on the invention. Computer 1210 may be programmed to add
or remove controls as subgroups of electrically active sites are
defined.
[0092] FIG. 13B shows one way in which electrically active sites
may be assigned to each of the subgroups. A drop down list box 1360
is shown in connection with control 1353 corresponding to one of
the groups of electrically active sites. In this example, drop down
list 1360 includes an entry for each possible electrically active
site that may be added to the third subgroup. For simplicity of
illustration only entries 1361 and 1362 are numbered. Each entry
such as 1361 and 1362 includes a checkbox such as 1371 or 1372. The
check box may itself be a control through which a user using the
graphical user interface may provide input. By "clicking" on the
checkbox, a user may specify that a site belongs to the group. By
"clicking" on a checkbox that is already checked, the user may
specify that a site should be removed from the group.
[0093] A drop down list box may be associated with each of the
controls 1351, 1352 and 1353 may be accessed in any suitable way.
Where a multi-button mouse is used, the drop down list such as drop
down list 1360, for example, may be accessed by pressing the right
button on the mouse when curser 1340 is positioned over a control
such as 1353. However, any suitable method of assigning
electrically active sites to groups, including receiving text
input, may be used.
[0094] Once groups of electrically active sites have been defined,
the groups may be used in controlling the electrophysiology system.
For example, accessing one of the controls through the user
interface, such as by "clicking" on one of the controls 1351, 1352
or 1353, may cause all of the electrically active sites defined to
be in the group to be accessed. In a pace mapping mode, accessing a
group may cause all of the electronically active sites in that
group to be connected to RF generator 1240 through switch matrix
1230. In passive mapping mode, accessing a group may cause each of
the electrically active sites in that group to be connected through
switch matrix 1232 to recording device 2.
[0095] Once groups of electrically active sites have been defined,
groups may be accessed in an order and with the timing specified by
the user. One way for a user to specify the timing and access to
groups of sites is by manipulating curser 1340 to indicate one of
the controls such as 1351, 1352, or 1353 associated with a group.
The user may manually use a selection device, such as a button on
mouse 1214, to select the control. Upon selecting a control, the
electrically active sites in the group associated in the group
associated with that control may be accessed. In this way, the
groups will be accessed in an order specified by the user at times
specified by the user.
[0096] Computer 1210 may alternatively be programmed to provide an
alternative method for a user to specify the order and timing of
access to groups of electrically active sites. For example,
computer 1210 may implement a user interface in which the controls
such as control 1351, 1352, and 1353 are movable objects on the
graphical user interface. In this embodiment, the user may specify
the order of access to the groups by moving the controls into a
desired order.
[0097] The user may specify timing of access to the groups in any
suitable way. For example, computer 1210 may provide a user
interface with an input section (not shown), through which the user
may specify a time when each group of electrically active sites is
accessed. Alternatively, computer 1210 may receive inputs that
specify the duration for which each group is accessed or the delay
between accesses of successive groups. The information about
ordering and timing of access to the groups, regardless of how
specified by the user, creates a form of program that may be
executed by the electrophysiology system of FIG. 12. Accordingly,
window 1350 includes a control 1370 that the user may access.
Access and control 1370 may, for example, invoke a program that
accesses groups of electrically active sites in the order and with
the timing specified by the user. Such a function may be used in
the course of a mapping procedure to gather data intended to
identify the focus of an arrhythmia. Alternatively, such a
procedure may be used in connection with an ablation procedure
where the focus of the arrhythmia has been identified and a
specific pattern of applied RF energy has been selected for
treating the arrhythmia.
[0098] Turning now to FIG. 14, a process of accessing groups of
electrically active sites is illustrated. The process of FIG. 14
may, for example, be implemented by software programmed in computer
1210. The process begins at block 1410 where a group is specified.
A group may be specified by input from a user. The user input may
be obtained through a graphical user interface as depicted in FIGS.
13A and 13B. However, any suitable method of specifying a group may
be used.
[0099] The process illustrated in FIG. 14 continues to decision
block 1412. If it is determined at decision block 1412 that further
groups remain to be specified, processing loops back to step
1410.
[0100] When there are no further groups to specify, processing
continues to block 1414. At block 1414, the electrophysiology
system waits until the programmed time for the first group to be
processed is reached. At the programmed time, processing proceeds
to block 1416. At block 1416 the electrophysiology system is
configured for the group being processed. In the example of FIG.
12, configuration may include providing control information to
switch matrix 1230. Other devices within the electrophysiology
system may likewise be controlled to obtain the desired
configuration.
[0101] At block 1418, the desired function of the electrophysiology
system is applied. In this block, the function may be applied by
providing an RF signal of the appropriate magnitude or by making a
measurement from each of the electrically active sites in the
subgroup, depending on the specific operating mode of the
system.
[0102] The process proceeds to decision block 1420. At decision
block 1420 it is determined if there are more groups of
electrically active sites to be processed. If more groups remain,
processing returns to block 1414. The process waits at block 1414
until the time for processing the next group. At that time, the
process in blocks 1416, 1418, and decision block 1420 is
repeated.
[0103] In this way, the electrophysiology system allows a user to
control a catheter with electrically multiple active sites.
Flexible control is provided to allow the user to access these
sites singly or in groups and in a manual or automated fashion.
Such control capability when combined with a catheter that has
multiple electrically active sites on a substrate that may cover a
relatively large area, speeds procedures performed with the
electrophysiology system.
[0104] For example, the above described U.S. Published application,
US 2002/0065459-A1, entitled "SOFTWARE CONTROLLED ELECTROPHYSIOLOGY
DATA MANAGEMENT" describes the use of a roving catheter. That
patent application describes managing discrete data capture
requests throughout the course of an electrophysiology procedure. A
catheter as described above having a plurality of electrically
active sites that may be selected in groups may be used in place of
a roving catheter. Rather than repositioning a roving catheter
between independent data capture events, different groups of the
electrically active sites may be selected without moving the
catheter. The selection of groups may be made in response to manual
user inputs or may be performed programmatically based on a
predefined sequence for accessing groups of electrically active
sites.
[0105] As another example, published U.S. Patent Application US
2002/0091330-A1, entitled "METHODS FOR PROCESSING ELECTROCARDIAC
SIGNALS HAVING SUPERIMPOSED COMPLEXES" describes a reference ECG
waveform compared to an ECG waveform captured during pace mapping.
As part of such a method, a quality of match indicator is computed.
For pace mapping, the heart is stimulated with a roving
intercardiac catheter. A catheter having a plurality of
individually accessible electrically active sites as described
above may be used to perform such a procedure without moving a
roving catheter. Rather, stimulus may be provided to the heart in a
predictable, defined manner by selecting groups of the electrically
active sites on a single catheter.
[0106] More generally the catheter and controller described above
may be used in any procedure where accessing different locations is
desired. The access may be to sense signals in a passive mapping
procedure. Alternatively, the access may be to supply signals, such
as in a pace mapping or ablation process. Regardless of the
specific purpose of the access, allowing access in a predictable,
defined manner is advantageous. It avoids the random "hit and miss"
approach that characterizes many current procedures in which
locations in the heart are accessed through manipulation of a tip
of a catheter.
[0107] Having thus described several aspects of at least one
embodiment of this invention, it is to be appreciated that various
alterations, modifications, and improvements will readily occur to
those skilled in the art. Such alterations, modifications, and
improvements are intended to be part of this disclosure, and are
intended to be within the spirit and scope of the invention.
Accordingly, the foregoing description and drawings are by way of
example only.
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