U.S. patent application number 12/476823 was filed with the patent office on 2009-09-24 for sensing cardiac contractile function.
Invention is credited to Jiang Ding, Yinghong Yu, Qingsheng Zhu.
Application Number | 20090240159 12/476823 |
Document ID | / |
Family ID | 21712009 |
Filed Date | 2009-09-24 |
United States Patent
Application |
20090240159 |
Kind Code |
A1 |
Yu; Yinghong ; et
al. |
September 24, 2009 |
SENSING CARDIAC CONTRACTILE FUNCTION
Abstract
Systems and methods for detecting and measuring cardiac
contractile function of a heart using an acceleration sensor unit
inserted within the heart, such as within a vein of the cardiac
wall are disclosed. The systems and methods involve detecting the
occurrence of electrical events within the patient's heart by
inserting and positioning an implantable lead having an electrode
near a cardiac wall as well as detecting mechanical events within
the patient's heart by then inserting and positioning a cardiac
motion sensor unit through the inner lumen of the implantable lead.
Furthermore, the systems and methods do not require dedicated leads
and may be used with preexisting implantable leads.
Inventors: |
Yu; Yinghong; (Shoreview,
MN) ; Ding; Jiang; (Shoreview, MN) ; Zhu;
Qingsheng; (Wexford, PA) |
Correspondence
Address: |
SCHWEGMAN, LUNDBERG & WOESSNER/BSC-CRM
PO BOX 2938
MINNEAPOLIS
MN
55402
US
|
Family ID: |
21712009 |
Appl. No.: |
12/476823 |
Filed: |
June 2, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11254344 |
Oct 20, 2005 |
7567838 |
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12476823 |
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|
10004686 |
Dec 5, 2001 |
6980866 |
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11254344 |
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|
10008397 |
Dec 6, 2001 |
6993389 |
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10004686 |
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Current U.S.
Class: |
600/513 |
Current CPC
Class: |
A61N 2001/0585 20130101;
A61N 1/3627 20130101; A61N 1/36514 20130101; A61N 1/36542
20130101 |
Class at
Publication: |
600/513 |
International
Class: |
A61B 5/0402 20060101
A61B005/0402 |
Claims
1. A cardiac apparatus comprising: a first lead including an inner
lumen, wherein the first lead includes a first conductor configured
to sense cardiac electrical activity; a second lead including a
second conductor configured to sense cardiac electrical activity,
wherein the first lead is disposed within the second lead; and a
sensing device configured to sense cardiac wall movement, the
sensing device disposed within the inner lumen of the first
lead.
2. The cardiac apparatus of claim 1, wherein the sensing device
includes a cardiac motion sensor including an accelerometer.
3. The cardiac apparatus of claim 1, wherein the first lead is
substantially concentrically disposed within the second lead.
4. The cardiac apparatus of claim 1, wherein the sensing device is
configured to fit within a vein of the cardiac wall.
5. The cardiac apparatus of claim 1, comprising a connector device
configured to connect the sensing device to an electronic
device.
6. The cardiac apparatus of claim 5, wherein the electronic device
includes an implantable device.
7. The cardiac apparatus of claim 5, wherein the connector device
is configured to fix the sensing device relative to the inner
lumen.
8. The cardiac apparatus of claim 5, wherein the sensing device
includes a cardiac motion sensor coupled to the connector device by
an elongate body.
9. The cardiac apparatus of claim 8, wherein the elongate body
includes an electrical conductor.
10. The cardiac apparatus of claim 1, wherein the sensing device is
removably disposed within the inner lumen.
11. The cardiac apparatus of claim 10, wherein the first lead is
configured to remain implanted with the sensing device removed from
within the inner lumen.
12. A cardiac system comprising: a first lead including an inner
lumen, wherein the first lead includes a first conductor configured
to sense cardiac electrical activity; a second lead including a
second conductor configured to sense cardiac electrical activity,
wherein the first lead is disposed within the second lead; and a
sensing device configured to sense cardiac wall movement, the
sensing device disposed within the inner lumen of the first lead,
the sensing device comprising: a cardiac motion sensor configured
to generate a signal indicative of cardiac wall movement; and a
connector device configured to fix the sensing device relative to
the inner lumen.
13. The cardiac system of claim 12, comprising an electronic device
coupled to the connector device of the sensing device, wherein the
electronic device is configured to receive from the cardiac motion
sensor the signal indicative of cardiac wall movement.
14. The cardiac system of claim 13, wherein the electronic device
includes an implantable device.
15. The cardiac system of claim 13, wherein the sensing device is
fixed relative to the inner lumen when the connector device is
coupled to the electronic device.
16. The cardiac system of claim 13, wherein the sensing device
includes an elongate body connecting the cardiac motion sensor to
the connector device.
17. The cardiac system of claim 16, wherein the elongate body is
configured to transmit the signal indicative of cardiac wall
movement from the cardiac motion sensor to the electronic
device.
18. The cardiac system of claim 12, wherein the sensing device
includes an elongate body connecting the cardiac motion sensor to
the connector device.
19. The cardiac system of claim 12, wherein the sensing device is
removably disposed within the inner lumen.
20. The cardiac system of claim 12, wherein the first lead is
substantially concentrically disposed within the second lead.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 11/254,344, filed Oct. 20, 2005, which is a divisional of U.S.
patent application Ser. No. 10/004,686, filed Dec. 5, 2001, now
issued as U.S. Pat. No. 6,980,866, which is a divisional of
co-pending U.S. patent application Ser. No. 10/008,397, filed Dec.
6, 2001, now issued as U.S. Pat. No. 6,993,389, said applications
are incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention relates to cardiac sensing devices.
More specifically, the present invention relates to insertable
acceleration sensor units that provide signals representative of
cardiac mechanical activity.
BACKGROUND
[0003] Implantable cardiac sensing and stimulating devices are
generally used to manage a variety of heart arrhythmias and
conduction system blockages. Heart arrhythmias, such as bradycardia
and tachycardia, often prevent the heart from pumping an adequate
amount of blood. When the body does not receive enough
oxygen-carrying blood, symptoms such as fatigue, shortness of
breath, dizziness, and unconsciousness may occur. Furthermore,
conduction system blockages in the heart cause slow, asynchronous
contractions that reduce the pumping efficiency and lower cardiac
output. Implantable cardiac sensing and stimulating devices must be
capable of detecting such arrhythmias and decreased pumping
efficiency due to conduction system blockages, and the implantable
device should respond to the detected arrhythmia or low pumping
efficiency by providing therapeutic electrical stimulation.
[0004] Accurate measurement of cardiac activity is needed to
deliver effective therapy by an implantable cardiac sensing and
stimulating device. Many cardiac sensing and stimulating devices
that detect and distinguish among cardiac sensing and stimulating
devices that detect and distinguish among cardiac arrhythmias
monitor heart rate, which is usually accomplished by measuring
cardiac electrical activity. Furthermore, the functions of the
conduction system and synchronization of cardiac wall contractions
are assessed by measuring and analyzing cardiac electrical
activity. However, electrical activity is not a sufficiently
accurate representation of the mechanical function of the heart.
Thus, using only electrodes to sense cardiac mechanical activity
can have some disadvantages in some circumstances.
[0005] Some implantable cardiac sensing and stimulating devices
include implantable leads with built-in accelerometers to measure
cardiac mechanical movement representative of cardiac contractile
function. However, built-in accelerometers typically require a
dedicated implantable lead, which tends to be bulky and hard to
handle. Furthermore, these conventional leads with built-in
accelerometers are too large to fit within a vein of a cardiac wall
and require invasive installation procedures.
[0006] Thus, it is desirable to provide an improved sensing method
and system for accurately detecting and monitoring cardiac
mechanical activities. Further, it is desirable to provide an
improved sensing method and system that has the ability to be
implanted without a dedicated lead, such as within a preexisting
implantable lead that may be positioned within a vein of a cardiac
wall.
SUMMARY
[0007] As embodied and broadly described herein, the present
invention relates to a method for detecting and measuring cardiac
contractile functions using a signal representative of cardiac wall
acceleration provided by an acceleration sensor unit. The method
involves introducing the acceleration sensor unit into a vein of
the cardiac wall and positioning the sensor so that it responds to
the acceleration of the cardiac wall and provides a signal
representative of the cardiac wall acceleration. The method further
involves connecting the acceleration sensor unit to an electronic
device.
[0008] Moreover, the present invention also relates to another
method for detecting and measuring cardiac contractile functions
using a signal representative of cardiac wall acceleration provided
by an acceleration sensor. This method involves inserting a guide
element along the inner lumen of an implantable lead. The method
also involves introducing the implantable lead into a vein of the
cardiac wall. The method further involves positioning the
implantable lead within the vein using the guide element and then
removing the guide element from the inner lumen of the implantable
lead. Finally, the method involves inserting the acceleration
sensor unit along the inner lumen of the implantable lead.
[0009] In another embodiment, the present invention relates to a
method for creating an acceleration sensor. This method involves
providing an implantable lead and inserting a cardiac motion sensor
along the inner lumen of the implantable lead. This method also
involves positioning the cardiac motion sensor within the lumen of
the implantable lead so that the cardiac motion sensor remains
mobile along the longitudinal axis of the implantable lead.
[0010] Further, the present invention also relates to a system for
detecting and measuring cardiac contractile functions. This system
includes an acceleration sensing means disposed at the cardiac wall
for providing a signal representative of acceleration of the
cardiac wall. This system also includes a conductor means molded
into an elongated insulator body for transmitting a signal
representative of acceleration of the cardiac wall from the
acceleration sensing means to the electronic sensing means. This
system further includes a connector means for electrically linking
the conductor means to the electronic sensing means.
[0011] The present invention also relates to another system for
detecting and measuring cardiac contractile functions. This system
includes an acceleration sensing device disposed at the cardiac
wall for providing a signal representative of acceleration of the
cardiac wall. The system also includes a conductor device molded
into an insulated elongate body for transmitting a signal
representative of acceleration of the cardiac wall from the
acceleration sensing device to the electronic device. This system
further includes a connector device for electrically linking the
conductor device to the electronic device.
[0012] Advantages of the invention will be set forth in part in the
description which follows or may be learned by practice of the
invention. It is to be understood that both the foregoing general
description and the following detailed description are exemplary
and explanatory only and are not restrictive of the invention, as
claimed.
DESCRIPTION OF DRAWINGS
[0013] FIG. 1 is a schematic representation of a typical human
heart with acceleration sensor units in accordance with embodiments
of the present invention;
[0014] FIG. 2 depicts an acceleration sensor unit in accordance
with an embodiment of the present invention;
[0015] FIG. 3 illustrates an implantable lead incorporating a guide
element and an acceleration sensor unit in accordance with an
embodiment of the present invention;
[0016] FIG. 4 is a flow chart representing an exemplary method into
which an embodiment of the present invention may be
incorporated.
DETAILED DESCRIPTION
[0017] Various embodiments of the present invention will be
described in detail with reference to the drawings, wherein like
reference numerals represent like parts and assemblies through the
several views. Reference to various embodiments does not limit the
scope of the invention, which is limited only by the scope of the
claims attached hereto.
[0018] Embodiments of the present invention allow detection and
measurement of cardiac contractile functions by an acceleration
sensor unit inserted within the heart, such as within a vein of the
cardiac wall. These embodiments also provide systems and methods
that may be used without requiring a dedicated lead for the
acceleration sensor. Further, these embodiments provide systems and
methods that may be used with preexisting leads. Certain of these
embodiments also provide systems and methods that may be removed
from implantable leads without disturbing the position of the
implantable lead within the heart 100.
[0019] FIG. 1 is a schematic representation of a typical human
heart with acceleration sensor units in accordance with embodiments
of the present invention. In FIG. 1, the heart 100 comprises the
upper heart chambers, the right atrium area 106 and left atrium
area 102, and the lower heart chambers, the right ventricle area
108 and left ventricle area 104. The coronary sinus 110 extends
from the opening in the right atrium 106 laterally around the atria
to form the great cardiac vein that extends further inferiorly into
branches of the great cardiac vein. An electronic device 22 having
leads 24, 26 is implanted in a human body (not shown) with portions
of the implantable leads 24 and 26 inserted into the heart 100
and/or veins of the heart 100. The device 22 is used to detect and
analyze electrical cardiac signals and signals indicative of
cardiac wall acceleration produced by the heart 100 and to provide
electrical energy to the heart 100 under certain predetermined
conditions to treat arrhythmias or conduction system blockages. As
shown, the electronic device 22 may be an implantable cardiac
resynchronization device for establishing synchronization of
ventricular wall contractions, such as for patients with a left
bundle branch blockage.
[0020] The implantable leads 24 and 26 comprise elongate bodies,
both having a proximal end, 32 and 36 respectively, and a distal
end, 35 and 38 respectively. The implantable leads 24 and 26
further include one or more pacing/sensing electrodes 50, 52
respectively and/or one or more acceleration sensor units 46, 44.
The implantable lead 26 is passed through a vein into the right
atrium chamber 106 of the heart 100, into the coronary sinus 110
and then inferiorly in the great cardiac vein in a basal region to
extend the electrode 52 located at the distal end 38 onto the
cardiac wall alongside the left atrium chamber 102 of the heart
100. In an alternative embodiment, the implantable lead 26 may be
extended further into the coronary sinus 110 and anterior and/or
lateral veins extending therefrom to extend the electrode 52
located at the distal end 38 onto the cardiac wall alongside the
left ventricle chamber 104 of the heart 100. In one embodiment, the
implantable lead 26 is fixed in place by a distal fixation
mechanism 70 comprising a plurality of fixation tines well known in
the art. When the implantable lead 26 is positioned within the
coronary sinus 110, an acceleration sensor unit 44 is passed
through the inner lumen 28 of the implantable lead 26 to extend the
cardiac motion sensor 42, such as an accelerometer, of the
acceleration sensor unit 44 alongside preferably either the left
ventricle chamber 104 or left atrium chamber 102 of the heart 100.
The acceleration sensor unit 44 may be removed from the inner lumen
28 of the implantable lead 26 without removing the implantable lead
26 from the coronary sinus 110 of the heart 100.
[0021] In an additional embodiment, the implantable lead 24 is
passed into the right atrium chamber 106 of the heart 100 and
through the tricuspid valve into the right ventricle 108 where the
electrode 50, located at the distal end 35, is fixed in place in
the interventricular septum by a distal attachment mechanism 62.
The distal attachment mechanism 62 may be a wire shaped into a
helical cork-screw like projection, a plurality of fixation tines
projecting away from the peripheral surface of the implantable lead
24, or other structures for attaching the lead 24. Such distal
attachment mechanisms are well known in the art and are intended to
embed the distal end of the lead 24 in the tissue of the heart.
When the implantable lead 24 is fixed in place, an acceleration
sensor unit 46 is passed through the inner lumen 20 of the
implantable lead 24 to extend the cardiac motion sensor 40 located
at the distal end of the acceleration sensor unit 46 to the
interventricular septum. The acceleration sensor unit 46 may be
later removed from the inner lumen 20 of the implantable lead 24,
if necessary, without removing the implantable lead 24 from the
interventricular septum of the heart 100.
[0022] The implantable device 22 may detect electrical events as
well as mechanical events within the heart 100. The electrodes 50,
52 placed into the heart 100, including the electrode in the
coronary sinus vein branch 110, sense the naturally occurring
depolarization of the cells as the electrical wave travels past the
electrode 50, 52 down the surface of the heart 100 from the atrium
area to the ventricle area. The acceleration sensor units 44, 46
inserted through the inner lumens 20, 28 of the implantable leads
24, 26 sense the cardiac contractile functions by providing a
signal indicative of cardiac wall acceleration.
[0023] The illustrated types and locations of implantable leads 24,
26, electrodes 50, 52 and acceleration sensor units 44, 46 are
merely exemplary. It will be understood that one or more other
types of endocardial and epicardial leads, electrodes and
acceleration sensor units located in or about the right and left
chambers of the heart 100 as well as the coronary sinus 110 can be
substituted for those illustrated in FIG. 1 described above.
[0024] FIG. 2 illustrates an example of an acceleration sensor unit
in accordance with the present invention. In FIG. 2, the
acceleration sensor unit 44 comprises a cardiac motion sensor 42
and a connector 45 coupled together by an elongate body 41. The
elongate body 41 comprises two electrical conductors 43, 47
encompassed by an insulator 49 extending longitudinally. The
electrical conductors 43, 47 electrically connect the cardiac
motion sensor 42 located at the distal end of the acceleration
sensor unit 44 with the connector 45 located at the proximal end of
the acceleration sensor unit 44. In one embodiment, the insulator
49 of the elongate body 41 is an implantable polyurethane, silicone
rubber or other implantable flexible polymer. At the distal end of
the acceleration sensor unit 44, the electrical conductors 43, 47
connect with the cardiac motion sensor 42. At the proximal end of
the acceleration sensor unit 44, the electrical conductors 43, 47
connect with the connector 45. Standard electrical bipolar or
unipolar connectors may be used as the connector 45, which provides
mechanical and electrical connections to the electronic device 22.
The electrical conductors 43, 47 transmit the signal indicative of
cardiac wall motion from the cardiac motion sensor 42 to the
electronic device 22.
[0025] In accordance with the present invention, a preferred
embodiment of the cardiac motion sensor 42 is constructed as an
accelerometer that is particularly sized for incorporation within a
vein of a cardiac wall of the heart 100. In another embodiment, the
cardiac motion sensor 42 is constructed as an accelerometer that is
particularly sized for incorporation in an implantable lead within
a vein of a cardiac wall of the heart 100. Suitable accelerometers
include, for example, the miniaturized accelerometer provided by
Ball Semiconductor Inc. (see U.S. Pat. No. 6,197,610) and others
that has a diameter of approximately 1 millimeter. The cardiac
motion sensor 42 can be an accelerometer formed by any available
technology such as piezoelectric, piezoresistive, capacitive,
inductive, or magnetic. The cardiac motion sensor 42 detects and
measures cardiac wall motion and provides a signal representative
of cardiac wall acceleration to the electrical conductors 43, 47
which then transmit the signal to the electronic device 22.
[0026] FIG. 3 illustrates an implantable lead 26 incorporating a
guide element 60 and an acceleration sensor unit 44 in accordance
with the present invention. The implantable lead 26 comprises a
cylindrical lead 34 with a conductor used for sensing cardiac
electrical activity and delivering stimulation to the cardiac wall.
The cylindrical lead 34 is concentrically encompassed by a second
cylindrical lead 30 possessing a similar conductor, and the
cylindrical lead 34 has an inner lumen 28. The conductor of the
cylindrical lead 34 and second cylindrical lead 30 may be an
electrically conductive metal, as known in the art, formed into an
insulated coil configuration such as the Guidant EASYTRAK lead, or
in other configurations such as a woven conductor. Moreover, the
cylindrical lead 34 and second cylindrical lead 30 may have tapered
distal ends.
[0027] The implantable lead 26 is adapted to receive a guide
element 60 along the inner lumen 28 of the implantable lead 26 for
stiffening and shaping the implantable lead 26 during the insertion
of the implantable lead 26 into the heart 100. Preferable guide
elements include, for example, standard percutaneous transluminal
coronary angioplasty guide wires. Once the guide element 60 is used
to position the implantable lead 26 within the heart 100 or veins
of the heart 100, the guide element 60 is removed from the inner
lumen 28 of the implantable lead 26.
[0028] In an embodiment of the present invention, acceleration
sensor unit 44 is passed through the inner lumen 28 extending along
the longitudinal axis of the implantable lead 26 after the
implantable lead 26 is positioned within the heart 100, such as
within the coronary sinus 110. The acceleration sensor unit 44 is
extended into the implantable lead 26 to optimally position the
cardiac motion sensor 42 of the acceleration sensor unit 44. For
example, the sensor 42 may be positioned adjacent to the left
atrium chamber 102 or left ventricle chamber 104 of the heart 100.
Once an optimal position for the cardiac motion sensor 42 is
achieved, the acceleration sensor unit 44 is fixed relative to the
longitudinal axis of the inner lumen 28 of the implantable lead 26
by connecting connector 45 to the electronic device 22. In this
embodiment, the connector 45 may be disconnected from the
electronic device 22, and the acceleration sensor unit 44 may be
removed from the inner lumen 28 of the implantable lead 26 without
removing the implantable lead 26 from the heart 100.
[0029] FIG. 4 illustrates the steps representing a method into
which the present invention may be incorporated. At Step 200, a
guide element 60 is inserted along the inner lumen 28 of an
implantable lead 26. At Step 205, the implantable lead 26 is
introduced into the heart 100, such as within the coronary sinus
vein 110 of a cardiac wall. At Step 210, the implantable lead 26 is
positioned within the heart 100, such as within the coronary sinus
vein 110, using the guide element 60. At Step 215, once the
implantable lead 26 has been sufficiently positioned within the
heart 100, the guide element 60 is removed from the inner lumen 28
of the implantable lead 26. At Step 220, the acceleration sensor
unit 46 is inserted along the inner lumen 28 of the implantable
lead 26. Subsequently, should it be necessary, the acceleration
sensor unit 46 may be removed from the lead 26 while the lead 26
remains installed in the heart 100.
[0030] While the invention has been particularly shown and
described with reference to preferred embodiments thereof, it will
be understood by those skilled in the art that various other
changes in the form and details may be made therein without
departing from the spirit and scope of the invention.
* * * * *