U.S. patent application number 10/897504 was filed with the patent office on 2005-01-06 for cardiac stimulating apparatus having a blood clot filter and atrial pacer.
Invention is credited to Pappu, Ramesh.
Application Number | 20050004641 10/897504 |
Document ID | / |
Family ID | 23138789 |
Filed Date | 2005-01-06 |
United States Patent
Application |
20050004641 |
Kind Code |
A1 |
Pappu, Ramesh |
January 6, 2005 |
Cardiac stimulating apparatus having a blood clot filter and atrial
pacer
Abstract
An apparatus is provided for reducing the formation and
migration of blood clots from an atrial appendage, such as the left
atrial appendage, to the blood vessel system of a patient. The
apparatus comprises an atrial pacer to treat non-rheumatic atrial
fibrillation (NRAF) of an atrial appendage so that the formation
blood clots within the atrial appendage is decreased or eliminated.
In addition, the apparatus includes a blood clot filter supported
by the atrial pacer proximate the atrial appendage and the atrium
to reduce the migration of blood clots from the atrial appendage
into the blood vessel system of a patient.
Inventors: |
Pappu, Ramesh; (Cherry Hill,
NJ) |
Correspondence
Address: |
DANN, DORFMAN, HERRELL & SKILLMAN
1601 MARKET STREET
SUITE 2400
PHILADELPHIA
PA
19103-2307
US
|
Family ID: |
23138789 |
Appl. No.: |
10/897504 |
Filed: |
July 23, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10897504 |
Jul 23, 2004 |
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10163021 |
Jun 4, 2002 |
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60295683 |
Jun 4, 2001 |
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Current U.S.
Class: |
607/122 |
Current CPC
Class: |
A61N 1/39622 20170801;
A61N 1/3621 20130101; A61N 1/3962 20130101 |
Class at
Publication: |
607/122 |
International
Class: |
A61N 001/05 |
Claims
What is claimed is:
1. A cardiac stimulating apparatus comprising: a stimulator
comprising an end for making at least one of sensing and
stimulating contact with a wall of a heart, said stimulator
comprising at least one of a sensor and a stimulator; and a
filtration device mounted to said stimulator distal the end thereof
and adapted for deterring movement of emboli through the filtration
device.
2. The cardiac stimulating apparatus according to claim 1 wherein
the filtration device comprises a plurality of spokes.
3. The cardiac stimulating apparatus according to claim 2 wherein
the spokes include tines to attach the filtration device to the
heart.
4. The cardiac stimulating apparatus according to claim 1 wherein
the spokes extend generally radially outwardly from the
stimulator.
5. The cardiac stimulating apparatus according to claim 1 wherein
the filtration device comprises a mesh.
6. The cardiac stimulating apparatus according to claim 1 wherein
the filtration device includes at least one of an expandable mesh
and a plurality of expandable spokes.
7. The cardiac stimulating apparatus according to claim 6 wherein
said one of said expandable mesh and said plurality of expandable
spokes are collapsible to be disposed near the stimulator for
implantation into the heart through a catheter.
8. The cardiac stimulating apparatus according to claim 1 wherein
stimulator includes a control unit adapted to be disposed external
to the heart.
9. The cardiac stimulating apparatus according to claim 8 wherein
the control unit is adapted to be in wireless communication with
the sensor.
10. The cardiac stimulating apparatus according to claim 8 wherein
the control unit is adapted to be in wireless communication with
the stimulator.
11. The cardiac stimulating apparatus according to claim 1 wherein
the stimulator is adapted to apply a stimulating signal to the
heart wall and the sensor is adapted to be in sensing contact with
the heart wall.
12. The cardiac stimulating apparatus according to claim 1
comprising: i) a charger adapted to be disposed external to a
patient's body for providing a power signal in the form of
electromagnetic energy; and ii) an energizer adapted to be disposed
internal to a patient's body for receiving the power signal
provided by the generator unit to energize said stimulator.
13. The cardiac stimulating apparatus according to claim 12 wherein
the generator unit comprises a first coil for transmitting the
power signal and the energizing unit comprises a second coil for
receiving the power signal.
14. A cardiac stimulating apparatus comprising: a stimulator
comprising an elongated body adapted at one end thereof for making
at least one of sensing and stimulating contact with a wall of an
atrial appendage of a heart, said stimulator comprising an atrial
sensor and an atrial stimulator disposed in said elongated body;
and a filtration device mounted to said elongated body distal the
one end thereof and adapted for deterring movement of emboli
between the atrial appendage and an atrium of the heart.
15. The cardiac stimulating apparatus according to claim 14 wherein
the filtration device comprises a plurality of spokes.
16. The cardiac stimulating apparatus according to claim 15 wherein
the spokes include tines to attach the filtration device to the
atrial appendage.
17. The cardiac stimulating apparatus according to claim 14 wherein
the spokes extend generally radially outwardly from the
stimulator.
18. The cardiac stimulating apparatus according to claim 14 wherein
the filtration device comprises a mesh.
19. The cardiac stimulating apparatus according to claim 14 wherein
the filtration device includes at least one of an expandable mesh
and a plurality of expandable spokes.
20. The cardiac stimulating apparatus according to claim 19 wherein
said one of said expandable mesh and said plurality of expandable
spokes are collapsible to be disposed near the stimulator for
implantation into the atrial appendage through a catheter.
21. The cardiac stimulating apparatus according to claim 14 wherein
the stimulator includes a control unit adapted to be disposed
external to the heart.
22. The cardiac stimulating apparatus according to claim 21 wherein
the control unit is adapted to be in wireless communication with
the sensor.
23. The cardiac stimulating apparatus according to claim 21 wherein
the control unit is adapted to be in wireless communication with
the stimulator.
24. The cardiac stimulating apparatus according to claim 14 wherein
the stimulator is adapted to apply a stimulating signal to the wall
of the atrial appendage and the sensor is adapted to be in sensing
contact with a wall of the atrial appendage.
25. The cardiac stimulating apparatus according to claim 14
comprising: i) a charger adapted to be disposed external to a
patient's body for providing a power signal in the form of
electromagnetic energy; and ii) an energizer adapted to be disposed
internal to a patient's body for receiving the power signal
provided by the generator unit to energize said stimulator.
26. The cardiac stimulating apparatus according to claim 25 wherein
the generator unit comprises a first coil for transmitting the
power signal and the energizing unit comprises a second coil for
receiving the power signal.
Description
RELATED APPLICATIONS
[0001] This is a continuation application of U.S. application Ser.
No. 10/163,021, filed Jun. 4, 2002, which in turn claims the
benefit of priority of U.S. Provisional Application No. 60/295,683,
filed on Jun. 4, 2001, the entire contents of which application(s)
are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates generally to a device that
deters migration of emboli from an atrial appendage into the
vascular system of a patient, and more particularly to a device
that includes a filter to deter such migration and a pacer to deter
the formation of emboli such as blood clots within the atrial
appendage.
BACKGROUND OF THE INVENTION
[0003] Non-rheumatic atrial fibrillation (NRAF) is associated with
thromboembolic complications such as strokes. For example, when a
thrombus or embolus occludes a vessel supplying blood to the brain,
a stroke may result causing temporary or lasting paralysis of a
part of the body or, in severe cases, death. Blockage of other
blood vessels can occur as well causing attendant health concerns,
including heart attack or gangrene. Presently, a five percent risk
of stroke per year in a largely aging population causes NRAF to be
a significant health concern. Given the potentially irreversible
and destructive nature of such blood vessel occlusion, safe and
effective methods are needed to eliminate embolic material like
blood clots from the vascular system, some of which may be formed
within an atrial appendage of the heart.
[0004] The left atrial appendage forms a small protrusion which is
attached to the lateral wall of the left atrium between the mitral
valve and the root of the left pulmonary vein and normally
contracts along with the left atrium. Atrial fibrillation is a
cardiac condition wherein the atria beat faster than the
ventricles, causing the ventricles to contract irregularly and
consequently eject less blood into the vascular system. A major
problem associated with atrial fibrillation is pooling of blood in
the left atrial appendage.
[0005] During NRAF the left atrial appendage may not fully
contract, leaving stagnant blood within the left atrial appendage.
In turn, the stagnant blood may create a condition favorable to the
formation of blood clots within the left atrial appendage. Such
clots may travel from the left atrial appendage into the left
atrium and into the vascular system, thereby increasing the danger
of stroke or cardiac blockage.
[0006] Traditional treatments to mitigate the risks posed by blood
clots include the use of anticoagulants to dissolve the clots. For
example, recently published results from stroke prevention trials
suggest that prophylaxis with anticoagulation is beneficial to
patients with non-rheumatic, non-valvular atrial fibrillation.
Current therapeutic interventions include anticoagulation with
coumedin. In addition, therapeutic interventions include the use of
atrial rate regulating medications. However, both of these
treatment approaches pose potential complications such as internal
bleeding, as well as other negative side effects caused by the rate
regulating therapeutic agents.
[0007] In addition to pharmacological treatments, complex radical
surgical methods are available to treat atrial fibrillation. Such
treatments include, for example, atrial incisions or removal of the
left atrial appendage, which have been attempted in a limited,
experimental way. Such approaches are highly invasive and pose a
risk of mortality to the patient. Thus, a pressing need exists for
means by which the formation of blood clots the left atrial
appendage is substantially deterred while preventing the migration
of any blood clots which may form from entering the vascular
system.
[0008] U.S. Pat. No. 6,152,144 to Lesh et al., for example,
discloses a device and method for obliterating or occluding a body
cavity or passageway. Specifically, the patent to Lesh is directed
to a device and method for obliterating or occluding the left
atrial appendage of a patient's heart. In one embodiment, Lesh et
al. disclose a frame structure having a barrier or mesh material
disposed over it to act as a barrier to the passage of embolic
material.
[0009] However, Lesh et al. do not disclose a device or method
suited to treat atrial fibrillation, or other arrhythmias of the
heart, to thereby prevent the formation of clots in the left atrial
appendage. As such, the barrier embodiment of Lesh et al. permits
ongoing formation of clots within the left atrial appendage, which
may eventually occlude the barrier material to prevent fluid flow
as well as embolic material flow through the occluded barrier. Such
a situation may present a health concern as the left atrial
appendage contracts and the blood enclosed therein is unable to
exit the left atrial appendage. Such contraction may result in an
increased pressure in the left atrial appendage capable of
weakening the wall of the left atrial appendage. Additionally, as
the barrier embodiment of Lesh et al. does not prevent the
formation of clots, it is possible that the volume of the left
atrial appendage may eventually be filled with coagulated blood.
Thus, filtering alone poses possible added health concerns.
[0010] Regarding the treatment of atrial fibrillation, it is known
to use a pacemaker, for example, as disclosed in U.S. Pat. No.
6,178,351 B1 to Mower. Mower discloses a pacemaker that is capable
of pacing the atria from multiple sites, but does not address
prevention of migration of embolic material within the vascular
system. Moreover, neither Mower nor Lesh suggests combining a pacer
with an embolic barrier for use in the heart.
[0011] Accordingly, there is a need for an apparatus for mitigating
the risks associated with emboli originating in the left atrial
appendage and also for reducing the tendency of such emboli, such
as blood clots, to form therein.
SUMMARY OF THE INVENTION
[0012] An apparatus is provided for deterring the formation and
migration of blood clots from an atrial appendage, such as a left
or right atrial appendage, into the blood vessel system, i.e.
vascular system, of a patient. In particular, an apparatus of the
present invention comprises an atrial pacer to treat non-rheumatic
atrial fibrillation (NRAF) or other arrhythmias of an atrial
appendage so that the formation of blood clots within such atrial
appendage is decreased or eliminated. In addition, the apparatus
provides a blood clot filter to deter the migration of blood clots
from an atrial appendage into the blood vessel system of a
patient.
[0013] More specifically, the apparatus comprises a filter for
reducing the transport of emboli from an atrial appendage to an
atrium of the heart. The filter is formed to provide a structure
suitable for separating blood clots from the blood and for reducing
passage of blood clots from the atrial appendage into the atrium
and general circulation. In accordance with one aspect of the
invention, the filter can take the form of a plurality of spokes
extending outwardly from the atrial pacer. In another aspect, the
filter can take the form of a mesh having pores sized to deter the
passage of blood clots.
[0014] In accordance with another aspect of the invention, the
apparatus comprises an atrial pacer which supports the filter
between an atrial appendage and the atrium. The atrial pacer is
adapted to be in contact with a wall of the atrial appendage so the
atrial pacer may detect and reduce atrial fibrillation in the
atrial appendage. The pacer also includes a sensor which may form
an integral part of the atrial pacer for sensing fibrillation in
the atrial appendage. In an alternative arrangement, the sensor may
be adapted to be positioned externally to the heart. In this
external arrangement, a lead wire may be provided between the
sensor and the atrial wall, to provide sensing contact between the
sensor and the atrial wall. The atrial pacer also comprises a
stimulator for stimulating the atrial appendage. The simulator may
take the form of an electrode for making electrical contact with
the wall of the atrial appendage to apply stimulating signals to
the atrial appendage. The stimulator may be activated in response
to a signal from the sensor indicating the presence of NRAF, or
other arrythmias, in the atrial appendage.
[0015] A control unit adapted to be positioned externally to the
heart may optionally be provided for controlling the atrial pacer.
The control unit may communicate with the sensor and/or the
stimulator using a lead wire or wireless technology. In addition,
the sensor may be disposed within the control unit. For example, in
the arrangement where the sensor is positioned externally to the
heart, the sensor may be incorporated within the control unit.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The foregoing summary and the following detailed description
of the preferred embodiments of the present invention will be best
understood when read in conjunction with the appended drawings, in
which:
[0017] FIG. 1 is a schematic perspective view showing an exemplary
device of the present invention having a mesh filter;
[0018] FIG. 2 is a schematic perspective view showing an exemplary
device of the present invention having a filter which includes a
plurality of spokes;
[0019] FIG. 3 is a schematic view of the exemplary device shown in
FIG. 1 disposed within a left atrial appendage;
[0020] FIG. 4 is a schematic view of the exemplary device shown in
FIG. 2 disposed within a left atrial appendage;
[0021] FIG. 5 is a schematic block diagram of a first exemplary
configuration of an atrial pacer of the present invention having a
control unit which includes a sensor and lead wire for detecting a
selected condition of the heart;
[0022] FIG. 6 is a block diagram of a second exemplary
configuration of an atrial pacer of the present invention having a
control unit for communication with stimulator and sensor;
[0023] FIG. 7 is a block diagram of a rechargeable configuration of
an atrial pacer of the present invention;
[0024] FIG. 8 is a schematic view of the exemplary device shown in
FIG. 1 with the filter collapsed against the body of the device;
and
[0025] FIG. 9 is a schematic view of the exemplary device shown in
FIG. 2 with the spokes collapsed against the body of the
device.
DETAILED DESCRIPTION OF THE INVENTION
[0026] A cardiac stimulating apparatus 10, 100 is provided for
substantially reducing the formation of blood clots in an atrial
appendage of a heart, such as the left atrial appendage 210, and
reducing the migration of such clots into the blood vessel system
of a patient. The apparatus 10, 100 comprises a filtration device
28, 124 to reduce migration of embolic material, such as blood
clots or the like. In addition, the apparatus 10, 100 includes an
atrial pacer 12, 112 to treat arrythmias, such as non-rheumatic
atrial fibrillation (NRAF), of the left atrial appendage 210 to
deter the formation blood clots within the left atrial appendage
210. FIGS. 1-4 depict the general structure of a cardiac
stimulating apparatus of the present invention, illustrating the
cooperation between the atrial pacer 12, 112 and the filtration
device, such as filter 28 or spokes 124.
[0027] Turning now to FIGS. 1 and 3, an embodiment of the present
invention is shown in which a cardiac stimulating apparatus 10
comprises an atrial pacer 12 having an elongated generally tubular
body 14 having first and second opposing ends 18, 30. The first end
18 of the atrial pacer 12 is adapted to contact the wall of the
left atrial appendage 210 to support the cardiac stimulating
apparatus 10 within the left atrial appendage 210. The first end 18
may include a sensing device 22 optionally disposed therein to
detect NRAF or other arrhythmias in the left atrial appendage 210.
In such a configuration, the sensing device 22 is adapted to be in
sensing contact with the wall of the left atrial appendage 210. The
first end 18 of the atrial pacer 12 also includes a stimulating
device 23 for stimulating the left atrial appendage 210 in response
to detection of NRAF by a detector, such as sensing device 22. The
stimulating device 23 includes an electrode adapted to be in
electrical contact with the wall of the atrial appendage 210 for
applying stimulating signals to the atrial appendage 210. By
application of an appropriate stimulating signal, NRAF can be
reduced or eliminated thereby reducing the tendency of blood within
the left atrial appendage 210 to form blood clots. The sensing
device 22 and stimulating device 23 may comprise components known
for use in atrial pacers.
[0028] Extending outwardly from the elongated generally tubular
body 14, a filtration device is provided to deter the migration of
blood clots from the left atrial appendage 210 into the left atrium
200 of the heart. As shown in FIG. 1, an embodiment of the
filtration device may take the form of a mesh-like or sieve-like
filter 28. The filter 28 may have a generally conical shape as
shown, for example, with the narrower end of the conical filter 28
attached to the atrial pacer 12 proximate to the first end 18 of
the atrial pacer 12. Alternatively, the filter 28 may be attached
to the atrial pacer 12 at any point along the elongated body 14.
The filter 28 may have any shape suited to substantially fill the
opening defined by the intersection of the left atrial appendage
210 and the left atrium 200, such as a portion of a sphere, flat
sheet, or other shape.
[0029] The mesh-like material of the filter 28 may be formed from a
metal, such as a stainless-steel, for example. Alternatively, the
filter 28 may be formed from a polymeric material, such as a Nylon
or Dacron mesh. Other suitable materials such as PTFE or polyamides
may also be used. In particular, it is preferable that the filter
28 be formed of a resilient material capable of being collapsed
about the body 14 of the atrial pacer 12, as shown in FIG. 8, to
facilitate introduction of the cardiac stimulating device 10 into a
patient, for example, via a catheter. The resilient material is
chosen such that upon removal of the cardiac stimulating device 10
from the catheter, the filter 28 expands to a desired shape and
size to permit the opening of the left atrial appendage 210 to be
substantially sealed. Regardless of the material from which the
filter 28 is formed, the filter 28 is formed to provide pores
having a transverse dimensions of about 1 mm or other size
sufficiently small to prevent the passage of blood clots or other
thromboembolic material of like or greater size. In particular, it
may be desirable for the pore size to have a transverse dimension
up to about 0.1 mm.
[0030] The wider end of the filter 28 includes a rim portion 20
which defines the base of the filter 28. The rim portion 20 is
sized to circumscribe the opening between the left atrial appendage
210 and left atrium 200, so that emplacement the cardiac
stimulating device 10 in the left atrial appendage 210 generally
positions the rim portion 20 near the opening left atrial appendage
210 so as to form and maintain a seal therewith. To effect and
maintain such a seal, the rim portion 20 may be formed of or
covered by a soft polymer material. The rim portion 20 may have a
transverse dimension of about 2 to 40 mm, preferably about 25 to 35
mm. The transverse dimension of the rim portion 20 should be
selected with regard to the size of the left atrial appendage
opening, which may vary among patients, especially those patients
having heart disease related conditions.
[0031] The rim portion 20 may also include a plurality of holes
through which sutures may be placed to anchor the rim portion 20
proximate to the opening of the left atrial appendage 210.
Alternatively or additionally, the rim portion 20 may have a
spring-like action which causes the rim portion 20 to expand
generally radially outward from the longitudinal axis of the atrial
pacer 12, so that the rim portion 20 applies pressure against a
region proximate the opening of the left atrial appendage 210 to
form a seal proximate the opening of the left atrial appendage 210.
For example, the rim portion 20 may be formed of a shape memory
metal, such as NiTi, having a memorized shape larger than that of
the opening of the left atrial appendage 210 to supply the radially
outward pressure on the opening. The filter 28 is attached to the
atrial pacer 12 at such a location so as to permit the rim portion
20 to substantially form a seal within the left atrial appendage
opening and to permit the first end 18 of the atrial pacer 12 to
contact the wall of the atrial appendage 210.
[0032] Referring now to FIGS. 2 and 4, an alternative embodiment of
the cardiac stimulating apparatus 100 is shown where the filtration
device comprises a plurality of spokes 124 extending generally
radially outwardly from the atrial pacer 112, to deter the
migration of blood clots from the left atrial appendage 210 of the
heart to the left atrium 200 of the heart. The atrial pacer 112 of
the alternative embodiment comprises an elongated generally tubular
body 114 having first and second ends 118, 130, a stimulating
device 123, and an optional sensing device 122 similar to like
components 23 and 22 described above with regard to the previous
embodiment.
[0033] The spokes 124 each comprise a first end 125 attached to the
elongated body 114 of the atrial pacer 112 and a second end 127 of
the spokes 124 for engaging a region of the heart in the vicinity
of the left atrial appendage 210. The second end 127 of the spokes
124 may terminate in a hook-like tine 126 formed to anchor the
spokes 124 and retain the atrial pacer 112 within the left atrial
appendage 210. In addition, all or some of the second ends 127 of
the spokes 124 may include a hole suitable for placing a suture
therethrough for attachment to the left atrial appendage 210. The
number of spokes 124 employed should be sufficiently numerous to
create interstices between the spokes 124 sufficiently small to
deter the passage of embolic material through the interstices.
[0034] The first ends 125 of the plurality a spokes 124 may be
attached to the body 114 of the atrial pacer 112 at a common
distance from the first end 118 of the atrial pacer 112.
Alternatively, the first ends 125 of the plurality of spokes 124
may be attached to the body 114 of the atrial pacer 112 at varying
distances from the first end 118 of the atrial pacer 112. Providing
spokes 124 at a variety of distances from the first end 118 of the
atrial pacer 112 may be useful to create a tortuous path to deter
the flow of embolic material. For example, a first set of spokes
124 may have first ends 125 adjoining the atrial pacer 112 at a
common distance from the first end 118 around the circumference of
the atrial pacer 112. A second set of spokes may have first ends
adjoining the atrial pacer 112 at a further distance from the first
end 118 of the atrial pacer 112 than the first set of spokes 124.
In addition, the second set of spokes may be oriented
circumferentially to overlap with the interstices formed among the
first set of spokes 124, as viewed from the first end 118 of the
atrial pacer 112. Likewise, additional set of spokes 124 may be
included to effect additional blockage of embolic material flow.
Moreover, some or all of the spokes 124 may extend outwardly from
the atrial pacer 112 along non-radial directions, to enhance
blockage of embolic material.
[0035] The spokes 124 may be formed of any suitable material such
as a metal or polymeric material like those described above with
regard to the mesh-like filter 28. It is also desirable that the
spokes 124 be sufficiently pliable to permit the spokes 124 to be
disposed along the body 114 of the atrial pacer 112, as shown in
FIG. 9, while the cardiac stimulating device 100 is placed into a
patient via a catheter.
[0036] In addition, it is desirable that the spokes 124 be
sufficiently resilient so that they expand away from the body 114
of the atrial pacer 112 once removed from the catheter, permitting
the spokes 124 to engage the wall of left atrial appendage 210. In
addition, the spokes 124 are formed sufficiently long and disposed
at an angle away from the body 114 of the atrial pacer 112 to cause
the second ends 127 of the spokes 124 to be biased against the wall
of the left atrial appendage 210 to retain the cardiac stimulating
device 100 in position. For example, the spokes 125 may have a
length to allow the second ends 127 of the spokes 124 to terminate
proximate the left atrial appendage opening. The spokes 124 are
attached to the atrial pacer 112 at such a location as to permit
the spokes 124 to partially occlude the opening of the left atrial
appendage and to permit the first end 118 of the atrial pacer 112
to contact the wall of the atrial appendage 210.
[0037] In each of the above embodiments, the atrial pacer 12, 112
may include a power source 16, 116, such as a rechargeable battery,
within the generally elongated body 14, 114 along with appropriate
circuitry known for the operation of atrial sensing and stimulating
devices. Alternatively or additionally, the cardiac stimulating
device 10, 100 may include a lead wire 32, 132 to provide power
and/or a control signal to the atrial pacer 12, 112 from a remote
device. A control unit for use external to the left atrial
appendage 210, or external to a patient's body, may be provided for
housing circuitry of the atrial pacer 12, 112. Providing such a
control unit may also be desirable, since inclusion of control
circuitry therein may permit the atrial pacer 12, 112 to have a
smaller overall the size.
[0038] Referring to FIGS. 5-7, three exemplary embodiments are
shown of device arrangements which include remote control and/or
power supply units. In particular, with regard to FIG. 5, a control
unit 302 is shown for controlling and powering the stimulator 308
of an atrial pacer. The stimulator 308 may correspond to the
stimulating devices 23, 123 depicted in FIGS. 1 and 2 as described
above. In the configuration of FIG. 5, a sensor 304 is incorporated
in a remotely located control unit 302 rather than in the elongated
body 14, 114 of the atrial pacer 12, 112. The sensor 304 is in
sensing contact with the left atrial appendage 210 via lead wire
306 to detect NRAF in the atrial appendage 210. Hence, for this
configuration the sensing device 22, 122 described above as being
disposed within the first end 18, 118 of the atrial pacer 12,112 is
not required to be disposed therein.
[0039] The control unit 302 further includes control circuitry 310
for processing the signal detected by the sensor 304 and
controlling the stimulator 308 in response to the detected signal.
For example, when the control circuitry 310 receives a signal from
the sensor 304 indicative of NRAF of the left atrial appendage 210,
the control circuitry delivers a control signal to the stimulator
308 to cause the stimulator 308 to stimulate the left atrial
appendage 210 to alleviate the NRAF. Hence, by correcting NRAF,
formation of blood clots in the left atrial appendage 210 is
reduced by limiting the presence of stagnant blood in the left
atrial appendage 210. The control unit 302 communicates with the
stimulator 308 via an optional lead wire 309 or via wireless
communication.
[0040] Wireless communication can be effected via optional antennas
314, 315 connected to the control unit 302 and the stimulator 308,
respectively. The antenna 315 of the stimulator 308 may be
disposed, for example, at the second end 30, 130 of the atrial
pacer 12, 112. The control unit 302 may include a power source 312
to power the control unit 302 and to optionally power the
stimulator 308 via lead wire 307.
[0041] Referring to FIG. 6, a further embodiment of the present
invention is shown which is substantially similar to that shown in
FIG. 5. The embodiment of FIG. 6 differs from FIG. 5 in that the
control unit 402 of FIG. 6 does not include a sensor. Instead, a
sensor 404 is provided in the elongated body 14, 114 of the atrial
pacer 12, 112 along with a stimulator 408. Such a sensor 404 may
correspond to the sensing devices 22, 122 shown in FIGS. 1 and 2
and described above. Since the sensor 404 and stimulator 408 are
both disposed within the body 14, 114 of the atrial pacer 12, 112,
the sensor 404 and stimulator 408 may communicate directly with
each other so that the stimulator 408 may stimulate left atrial
appendage 210 in response to the detection of NRAF by the sensor
404. Alternatively, to minimize the size of the atrial pacer,
control circuitry may be provided in a remote control unit 402 to
receive data from the sensor 404, to process such data, and control
the stimulator 408 in response to such data. Communication between
the control unit 402 and the stimulator 408 and sensor 404 may be
effected via an optional lead wire 409 or via wireless
communication using optional antennas 414, 415, in a similar manner
to that described above with regard to the embodiment of FIG.
5.
[0042] In addition, as shown in FIG. 7, the atrial pacer 512 may be
configured to be recharged by a remote charger 506. In such an
embodiment, the atrial pacer 512 includes a first electrical coil
502 electrically coupled to an energizer unit 516, such as a
battery, of the atrial pacer 512. The recharger 506 has a
corresponding second electrical coil 504 which may be
electromagnetically coupled to the first coil 502 to transmit
electromagnetic energy thereto from the charger 506, through the
patient's skin 508, and thence into the energizer unit 516 of the
atrial pacer 512.
[0043] After insertion of the cardiac stimulating device 10, 100
into the heart so that the filtration device 28, 126 expands and
sensing device 22, 122 or sensor 304, 404 is placed in sensing
contact with the left atrial appendage 210, the cardiac stimulating
device 10, 100 monitors for the presence of NRAF. Upon detection of
NRAF, the stimulator 23, 123 applies a correcting stimulating
electrical signal to the left atrial appendage 210 in response to
the detected NRAF condition. By such treatment of the left atrial
appendage 210 to minimize NRAF, the formation of blood clots
attributable to NRAF is minimized. In addition, the presence of the
filtration device 28, 126 provides continuous filtration of the
blood exiting the left atrial appendage 210, so as to prevent the
egress of emboli therefrom.
[0044] These and other advantages of the present invention will be
apparent to those skilled in the art. Accordingly, it will be
recognized by those skilled in the art that changes or
modifications may be made to the above-described embodiments
without departing from the broad inventive concepts of the
invention. For example, the atrial pacer could be replaced and/or
adapted to function as a ventricular defibrillator to treat
ventricular tachycardia. Likewise, the atrial pacer could be
replaced by a device that functions as a combined atrial pacer and
ventricular defibrillator. It should therefore be understood that
this invention is not limited to the particular embodiments
described herein, but is intended to include all changes and
modifications that are within the scope and spirit of the invention
as set forth in the claims.
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