U.S. patent application number 15/005221 was filed with the patent office on 2016-05-19 for pacing and sensing vectors.
The applicant listed for this patent is Cardiac Pacemakers, Inc.. Invention is credited to Russell E. Anderson, Jeffrey E. Stahmann, Bruce Alan Tockman, Rene H. Wentkowski, Randy Westlund.
Application Number | 20160136433 15/005221 |
Document ID | / |
Family ID | 44278102 |
Filed Date | 2016-05-19 |
United States Patent
Application |
20160136433 |
Kind Code |
A1 |
Stahmann; Jeffrey E. ; et
al. |
May 19, 2016 |
PACING AND SENSING VECTORS
Abstract
A method for allowing cardiac signals to be sensed and pacing
pulse vectors to be delivered between two or more electrodes. In
one embodiment, cardiac signals are sensed and pacing pulse vectors
are delivered between at least one of a first left ventricular
electrode and a second left ventricular electrode. Alternatively,
cardiac signals are sensed and pacing pulse vectors are delivered
between different combinations of the first and second left
ventricular electrodes and a first supraventricular electrode. In
addition, cardiac signals are sensed and pacing pulse vectors are
delivered between different combinations of the first and second
left ventricular electrode, the first supraventricular electrode
and a conductive housing. In an additional embodiment, a first
right ventricular electrode is used to sense cardiac signals and
provide pacing pulses with different combinations of the first and
second left ventricular electrodes, the first supraventricular
electrode and the housing.
Inventors: |
Stahmann; Jeffrey E.;
(Ramsey, MN) ; Tockman; Bruce Alan; (Scandia,
MN) ; Westlund; Randy; (River Falls, WI) ;
Wentkowski; Rene H.; (KAMP, DE) ; Anderson; Russell
E.; (Hopkins, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Cardiac Pacemakers, Inc. |
St. Paul |
MN |
US |
|
|
Family ID: |
44278102 |
Appl. No.: |
15/005221 |
Filed: |
January 25, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14290510 |
May 29, 2014 |
9278221 |
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15005221 |
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|
13075244 |
Mar 30, 2011 |
8798744 |
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14290510 |
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|
11554146 |
Oct 30, 2006 |
7945325 |
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13075244 |
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09779754 |
Feb 8, 2001 |
7130682 |
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11554146 |
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Current U.S.
Class: |
607/17 |
Current CPC
Class: |
A61N 1/36514 20130101;
A61N 1/3622 20130101; A61N 1/3712 20130101; A61N 1/365 20130101;
A61N 1/368 20130101 |
International
Class: |
A61N 1/365 20060101
A61N001/365; A61N 1/368 20060101 A61N001/368 |
Claims
1. (canceled)
2. A system, comprising: a sensing circuit configured to sense
cardiac signals; a stimulation circuit configured to generate and
deliver electrostimulation to a left ventricle of a heart; and a
control circuit coupled to the sensing circuit and the stimulation
circuit, the control circuit configured to program a pacing vector
for delivering the electrostimulation to the left ventricle of the
heart; wherein the control circuit is configured to alert the
pacing vector based on the sensed cardiac signals.
3. The system of claim 2, wherein: the sensed cardiac signals
include an intrinsic cardiac activity; and the control circuit is
configured to select a first pacing vector if the intrinsic cardiac
activity fails to satisfy a specified condition, or to select a
second pacing vector if the intrinsic cardiac activity satisfies
the specified condition.
4. The system of claim 2, wherein: the sensed cardiac signals
include an evoked cardiac activity sensed during the
electrostimulation according to the pacing vector; and the control
circuit is configured to alter from a first pacing vector to a
second pacing vector in response to the evoked cardiac activity
satisfying a specified condition.
5. The system of claim 2, comprising an implantable medical device
that includes at least a portion of one or more of the sensing
circuit, the stimulation circuit, or the control circuit.
6. The system of claim 4, wherein: the first pacing vector includes
a first anode and a first cathode each selected from two or more
electrodes on a first lead adapted to be positioned at or near a
left ventricle; or the second pacing vector includes a second anode
and a second cathode each selected from the two or more electrodes
on the first lead.
7. The system of claim 4, wherein: the first pacing vector includes
a first cathode selected from two or more electrodes on a first
lead adapted to be positioned at or near a left ventricle, and a
first anode selected from one or more electrodes on a second lead
adapted to be positioned at or near a region different from the
left ventricle; or the second pacing vector includes a second
cathode selected from the two or more electrodes on the first lead,
and a second anode selected from the one or more electrodes on the
second lead.
8. The system of claim 7, wherein the second lead is adapted to be
positioned at one of a supraventricular region, a right atrium, or
a right ventricle.
9. The system of claim 2, wherein: the sensing circuit is
configured to sense cardiac signals according to a first sensing
vector that includes a first combination of electrodes each
selected from two or more electrodes on a first lead or one or more
electrodes on a second lead; the control circuit, in response to
the sensed cardiac signals satisfying a specified condition, is
configured to: alter from the first sensing vector to a second
sensing vector that includes a second combination of electrodes
each selected from the two or more electrodes on the first lead or
the one or more electrodes on the second lead, the second
combination different from the first combination by at least one
electrode; and configure the sensing circuit to sense the cardiac
signals according to the second sensing vector.
10. The system of claim 9, wherein the first lead is adapted to be
positioned at or near a left ventricle, and the second lead is
adapted to be positioned at or near one of a supraventricular
region, a right atrium, or a right ventricle.
11. The system of claim 10, wherein the first or the second
combination of electrodes includes a first electrode selected from
the two or more electrodes on the first lead, and a second
electrode selected from the one or more electrodes on the second
lead.
12. The system of claim 10, wherein the first or the second
combination of electrodes includes first and second electrodes both
selected from two or more electrodes on the second lead adapted to
be positioned at the right ventricle.
13. A method for providing electrostimulation to a heart using an
implantable medical device, the method comprising: programming,
using a programming device, a pacing vector for delivering
electrostimulation to a left ventricle of a heart; sensing cardiac
signals with the implantable medical device; and altering the
pacing vector based on the sensed cardiac signals.
14. The method of claim 13, wherein the sensed cardiac signals
include an intrinsic cardiac activity, the method comprising:
selecting a first pacing vector if the intrinsic cardiac activity
fails to satisfy a specified condition; or selecting a second
pacing vector if the intrinsic cardiac activity satisfies the
specified condition.
15. The method of claim 13, wherein the sensed cardiac signals
include an evoked cardiac activity sensed during the
electrostimulation according to the pacing vector, and wherein
altering the pacing vector includes altering from a first pacing
vector to a second pacing vector in response to the evoked cardiac
activity satisfying a specified condition.
16. The method of claim 15, wherein: the first pacing vector
includes a first anode and a first cathode each selected from two
or more electrodes on a first lead adapted to be positioned at or
near a left ventricle; or the second pacing vector includes a
second anode and a second cathode each selected from the two or
more electrodes on the first lead.
17. The method of claim 15, wherein: the first pacing vector
includes a first cathode selected from two or more electrodes on a
first lead adapted to be positioned at or near a left ventricle,
and a first anode selected from one or more electrodes on a second
lead adapted to be positioned at or near a region different from
the left ventricle; or the second pacing vector includes a second
cathode selected from the two or more electrodes on the first lead,
and a second anode selected from the one or more electrodes on the
second lead.
18. A method for providing electrostimulation to a heart using an
implantable medical device, the method comprising: programming,
using a programming device, a stimulation vector for delivering
electrostimulation to a left ventricle of a heart and a sensing
vector for sensing cardiac signals; sensing cardiac signals with
the implantable medical device; altering the sensing vector based
on the sensed cardiac signals.
19. The method of claim 18, wherein altering the sensing vectors
includes altering from a first sensing vector to a second sensing
vector in response to the sensed cardiac signals satisfying a
specified condition, wherein the first sensing vector includes a
first combination of electrodes and the second sensing vector
includes a second combination of electrodes, the first and second
combinations of electrodes each selected from two or more
electrodes on a first lead or one or more electrodes on a second
lead, the second combination different from the first combination
by at least one electrode.
20. The method of claim 18, wherein altering the pacing vector
includes altering from a first pacing vector to a second pacing
vector in response to the sensed cardiac signals satisfying a
specified condition, and wherein: the first pacing vector includes
a first anode and a first cathode each selected from two or more
electrodes on a first lead adapted to be positioned at or near a
left ventricle; and the second pacing vector includes a second
anode and a second cathode each selected from the two or more
electrodes on the first lead.
21. The method of claim 18, wherein altering the pacing vector
includes altering from a first pacing vector to a second pacing
vector in response to the sensed cardiac signals satisfying a
specified condition, and wherein: the first pacing vector includes
a first cathode selected from two or more electrodes on a first
lead adapted to be positioned at or near a left ventricle, and a
first anode selected from one or more electrodes on a second lead
adapted to be positioned at or near a region different from the
left ventricle, and the second pacing vector includes a second
cathode selected from the two or more electrodes on the first lead,
and a second anode selected from the one or more electrodes on the
second lead.
Description
CLAIM OF PRIORITY
[0001] This application is a continuation of U.S. patent
application Ser. No. 14/290,510, filed on May 29, 2014, which
continuation of U.S. patent application Ser. No. 13/075,244, filed
on Mar. 30, 2011, now issued as U.S. Pat. No. 8,798,744, which is a
continuation of U.S. patent application Ser. No. 11/554,146, filed
on Oct. 30, 2006, now issued as U.S. Pat. No. 7,945,325, which is a
continuation of U.S. patent application Ser. No. 09/779,754, filed
on Feb. 8, 2001, now issued as U.S. Pat. No. 7,130,682, the benefit
of priority of each of which is hereby claimed, and each of which
is hereby incorporated by reference herein in its entirety.
TECHNICAL FIELD
[0002] The present invention relates to implantable medical
devices, and more particularly to sensing and delivering energy
pulses to and from the coronary vasculature.
BACKGROUND
[0003] Cardiac pulse generator systems include a battery powered
pulse generator and one or more leads for delivering pulses to the
heart. Current pulse generators include electronic circuitry for
determining the nature of an irregular rhythm, commonly referred to
as arrhythmia, and for timing the delivery of a pulse for a
particular purpose. The pulse generator is typically implanted into
a subcutaneous pocket made in the wall of the chest. Insulated
wires called leads attached to the pulse generator are routed
subcutaneously from the pocket to the shoulder or neck where the
leads enter a major vein, usually the subclavian vein. The leads
are then routed into the site of pacing, usually a chamber of the
heart. The leads are electrically connected to the pulse generators
on one end and are electrically connected to the heart on the other
end. Electrodes on the leads provide the electrical connection of
the lead to the heart. The leads are used to sense cardiac signals
from the heart and to deliver electrical discharges from the pulse
generator to the heart.
[0004] The electrodes are typically arranged on a lead body in two
ways or categories. A pair of electrodes which form a single
electrical circuit (i.e., one electrode is positive and one
electrode is negative) positioned within the heart is a bipolar
arrangement. The bipolar arrangement of electrodes requires two
insulated wires positioned within the lead. When one electrode is
positioned in or about the heart on a lead and represents one pole
and the other electrode representing the other pole is the pulse
generator housing, this arrangement is known as a unipolar
arrangement. The unipolar arrangement of electrodes requires one
insulated wire positioned within the lead.
[0005] In general, the heart can be divided into two sides, a right
side and a left side. Each side serves a specific function. The
right side of the heart receives blood from the body and pumps it
into the lungs to exchange gases. The left side of the heart
receives the oxygenated blood from the lungs and pumps it to the
brain and throughout the body.
[0006] Typically, pacing and defibrillation leads are positioned
within the right chambers of the heart, or positioned within the
coronary vasculature so as to position one or more electrodes
adjacent a left ventricular region of the heart. From their
positions within or adjacent to the ventricular chambers, the
electrodes on the leads are used to sense cardiac signals and to
deliver energy pulses in either a bipolar or a unipolar fashion.
This sensing and pacing, however, is accomplished only within or
across the chamber in which the lead is implanted. Thus, there
exists a need in the art for providing additional options in
sensing and delivering electrical energy pulses to a patient's
heart.
SUMMARY
[0007] The present subject matter provides for an apparatus and
method for allowing cardiac signals to be sensed and pacing pulse
vectors to be programmed for being delivered between two or more
electrodes. In one embodiment, the present subject matter allows
for cardiac signals to be sensed and pacing pulse vectors to be
delivered between at least one of a first left ventricular
electrode and a second left ventricular electrode in a left
ventricular region. In an additional embodiment, cardiac signals
are sensed and pacing pulse vectors are delivered between different
combinations of the first and/or second left ventricular electrodes
in a left ventricular region and a first supraventricular electrode
in a right atrial region. In addition, cardiac signals are sensed
and pacing pulse vectors are delivered between different
combinations of the first and/or second left ventricular electrodes
in a left ventricular region and a right ventricular electrode in a
right ventricular region. In addition, the housing of the apparatus
is conductive so as to allow cardiac signals to be sensed and
pacing pulse vectors to be delivered between different combinations
of the first and second left ventricular electrodes, the first
supraventricular electrode, the right ventricular electrode and the
housing.
[0008] In one embodiment, the apparatus includes an implantable
pulse generator to which is attached a first lead and a second
lead. The first lead includes a first supraventricular electrode
adapted to be positioned in a right atrial region, and the second
lead includes the first and second left ventricular electrodes that
are both adapted to be positioned adjacent a left ventricular
region. The electrodes on the first and second leads are coupled to
the implantable pulse generator and to control circuitry within the
implantable pulse generator. In one embodiment, the control
circuitry includes a pacing output circuit that is programmable to
control delivery of pacing pulses between combinations of the first
and/or second left ventricular electrodes in the left ventricular
region and the first supraventricular electrode in the right atrial
region. In an additional embodiment, the pacing output circuit is
programmable to control delivery of pacing pulses between
combinations of the first and/or second left ventricular electrodes
in the left ventricular region and the right ventricular electrode
in the right ventricular region.
[0009] Examples of the pacing vectors include delivering pacing
pulses from the first left ventricular electrode as a cathode to
the first supraventricular electrode as an anode. Alternatively,
pacing pulses are delivered from the first and/or second left
ventricular electrode as a cathode to the right ventricular
electrode as an anode. In addition, the pacing output circuit
delivers the pacing pulse between the first left ventricular
electrode and the second left ventricular electrode in a left
ventricular region and the first supraventricular electrode. In
addition, the control circuitry includes an extended bipolar cross
chamber sensor that receives a cardiac signal sensed between the
first left ventricular electrode and the first supraventricular
electrode. Alternatively, the cardiac signal is sensed between the
second left ventricular electrode and the first supraventricular
electrode. Cardiac signals sensed between other combinations of the
electrodes, including electrodes in the right ventricle, are also
possible.
[0010] In one embodiment, the first lead further includes a right
ventricular electrode adapted to be positioned in a right
ventricular region. Cardiac signals are sensed and pacing pulse
vectors are delivered from various combinations of the right
ventricular electrode, the first supraventricular electrode, the
first and second left ventricular electrodes and the housing. For
example, the control circuitry directs the pacing output circuit to
deliver pacing pulses from the first left atrial electrode as an
anode to the right ventricular electrode as a cathode.
Alternatively, the pacing output circuit controls delivery of
pacing pulses between the first left ventricular electrode, or the
second left ventricular electrode and the conductive housing. In an
additional embodiment, the pacing output circuit controls delivery
of pacing pulses between the first left ventricular electrode and
the second left ventricular electrode and the right ventricular
electrode, where the first and second left ventricular electrodes
are common. Alternatively, the pacing output circuit controls
delivery of pacing pulses between the first left ventricular
electrode and the second left ventricular electrode and the right
ventricular electrode and the housing of the implantable pulse
generator, where the first and second left ventricular electrodes
are common and the right ventricular electrode and the housing are
common. In addition, the control circuitry allows for a cardiac
signal to be sensed between one of the first and second electrodes
and the right ventricular electrode and for pacing pulses to be
delivered between one, or both, of the first and second electrodes
and the right ventricular electrode.
[0011] Other combinations of sensing and pacing vectors are
possible, as will be more fully described below.
BRIEF DESCRIPTION OF THE FIGURES
[0012] FIG. 1 is one embodiment of an apparatus according to the
present subject matter that is implanted into a heart, from which
segments have been removed to show detail;
[0013] FIG. 2 is one embodiment of an apparatus according to the
present subject matter that is implanted into a heart, from which
segments have been removed to show detail;
[0014] FIG. 3 is a block diagram of electronic control circuitry
for one embodiment of an apparatus according to the present subject
matter;
[0015] FIG. 4 is one embodiment of an apparatus according to the
present subject matter that is implanted into a heart, from which
segments have been removed to show detail;
[0016] FIG. 5 is one embodiment of an apparatus according to the
present subject matter that is implanted into a heart, from which
segments have been removed to show detail;
[0017] FIG. 6 is a flow chart of a method according to one
embodiment of the present subject matter;
[0018] FIG. 7 is a flow chart of a method according to one
embodiment of the present subject matter;
[0019] FIG. 8 is a flow chart of a method according to one
embodiment of the present subject matter;
[0020] FIG. 9 is a flow chart of a method according to one
embodiment of the present subject matter; and
[0021] FIG. 10 is a block diagram of electronic control circuitry
for one embodiment of an apparatus according to the present subject
matter.
DETAILED DESCRIPTION
[0022] In the following detailed description, reference is made to
the accompanying drawings which form a part hereof, and in which is
shown by way of illustration specific embodiments in which the
invention may be practiced. These embodiments are described in
sufficient detail to enable those skilled in the art to practice
the invention, and it is to be understood that other embodiments
may be utilized and that structural changes may be made without
departing from the scope of the present invention. Therefore, the
following detailed description is not to be taken in a limiting
sense, and the scope of the present invention is defined by the
appended claims and their equivalents.
[0023] Traditional pacemakers allow for pacing and sensing vectors
from within single cardiac chambers. These vectors are typically
referred to as "unipolar" and "bipolar", depending upon the
relative proximity of the electrodes being used in the pacing
and/or sensing. Unipolar and/or bipolar sensing and pacing can be
performed within either the atrial chambers or the ventricular
chambers of the heart.
[0024] FIG. 1 provides an illustration of unipolar and bipolar
pacing and sensing vectors. In FIG. 1, there is shown an
implantable pulse generator 100 coupled to a first cardiac lead 104
and a second cardiac lead 108. Each of the first cardiac lead 104
and the second cardiac lead 108 includes a proximal end (110 for
the first lead 104 and 112 for the second lead 108) and a distal
end (114 for the first lead 104 and 116 for the second lead 108).
The first lead 104 further includes right ventricular electrodes
that include a first right ventricular electrode 118 and a second
right ventricular electrode 120. The first electrode 118 is shown
positioned at the distal end 114 (at the tip of the lead) and the
second electrode 120 is spaced proximal the first electrode 118 to
allow for both electrodes to be positioned in the right ventricle
122. The second lead 108 further includes a first atrial
sensing/pacing electrode 126 and a second atrial sensing/pacing
electrode 128. The first electrode 126 is shown positioned at the
distal end 116 (at the tip of the lead) and the second electrode
128 is spaced proximal the first electrode 126 to allow for both
electrodes to be positioned in the right atrium 130. The cardiac
leads 104 and 108 further include insulated conductors that extend
between each of the electrodes and connectors at the proximal ends
110 and 112 of the first and second leads 104 and 108. The
connectors allow each of the electrodes (118, 120, 126 and 128) to
be coupled to electronic control circuitry within the implantable
pulse generator 100.
[0025] The electronic control circuitry is used to sense cardiac
signals and to deliver pacing pulses through the electrodes. A
bipolar vector for a chamber is only available when a lead with at
least two electrodes is implanted in, or near, a chamber of the
heart. In FIG. 1, each of the first lead 104 and the second lead
108 are shown with at least two electrodes implanted within a
chamber of the heart. With respect to the first lead 104, the
electronic control circuitry is used to sense and/or pace either in
a unipolar or a bipolar mode. Vector line 134 indicates either a
unipolar pacing pulse or a unipolar cardiac signal between one of
the first or second electrodes 118 or 120 and the housing 136 of
the implantable medical device 100. In an alternative embodiment,
vector line 138 indicates a bipolar pacing pulse or a bipolar
cardiac signal sensed between the first and second electrodes 118
and 120 on the first lead 104.
[0026] With respect to the second lead 108, the electronic control
circuitry is used to sense and/or pace either in a unipolar or a
bipolar mode. Vector line 140 indicates either a unipolar pacing
pulse or a unipolar cardiac signal between one of the first or
second electrodes 126 or 128 and the housing 136 of the implantable
medical device 100. In an alternative embodiment, vector line 144
indicates a bipolar pacing pulse or a bipolar cardiac signal sensed
between the first and second electrodes 126 and 128 on the second
lead 108. Different combinations of unipolar and bipolar sensing
and pacing from each of the first lead 104 and the second lead 108
are programmed into the electronic control circuitry through the
use of a medical device programmer 150.
[0027] In addition to the sensing and pacing vectors described
above, it has been found that additional sensing and pacing vectors
within and/or between cardiac chambers have benefits to providing
treatment to a patient. In one embodiment, the present subject
matter allows for additional sensing and/or pacing vectors between
(e.g., left ventricular chamber and right ventricular chamber, left
ventricular chamber and right atrial chamber, left atrial chamber
and right atrial chamber) and within cardiac chambers when one or
more cardiac leads are implanted in the left atrium and/or left
ventricular region in addition to leads being implanted in the
right ventricle and/or right atrium.
[0028] FIG. 2 shows one embodiment of an apparatus 200 according to
the present subject matter. In FIG. 2, the apparatus 200 includes a
first lead 204 and a second lead 226. The first lead 204 has a
proximal end 205 and a distal end 206 and includes a lead connector
207 having one or more connector terminals and a lead body 208. In
one embodiment, examples of the lead connector 207 and connector
terminals include, but are not limited to, LV-1, IS-1 UNI or IS-1
BI. Other lead connectors and connector terminals are possible. The
lead 204 releasably attaches to an implantable pulse generator
210.
[0029] In one embodiment, the lead 204 is adapted to be inserted
into and positioned within the right ventricle 214 and the right
atrium 215 of the heart 216. The lead 204 includes right
ventricular electrodes that include a first right ventricular
electrode 218 and a second right ventricular electrode 219. In one
embodiment, the first and second right ventricular electrodes 218
and 219 are adapted to be positioned in the right ventricular
region 214. In an additional embodiment, the first right
ventricular electrode 218 is a defibrillation coil electrode and
the second right ventricular electrode 219 is a distal tip
sensing/pacing electrode. In addition to the first and second right
ventricular electrodes, the first lead 204 further includes
additional electrodes, such as a first supraventricular electrode
220, where the first supraventricular electrode 220 is a
defibrillation coil electrode.
[0030] One example of the first lead 204 is an endocardial lead
sold under the trademark ENDOTAK (Cardiac Pacemaker, Inc./Guidant
Corporation, St. Paul, Minn.), which is a tripolar, endocardial
lead featuring a porous tip electrode. In one embodiment, the tip
electrode 219 is placed in the apex of the right ventricle and
serves as the cathode for intracardiac right ventricular
electrogram rate sensing and pacing. Additionally, the two
defibrillation coil electrodes serve as either an anode or a
cathode for rate sensing and/or morphology sensing and for
defibrillation. The present subject matter, however, uses the
electrodes as either anodes or cathodes depending upon the
programmed pacing and sensing vector direction.
[0031] The lead connector 207 electrically connects electrodes 218,
219 and 220 via conductors within the lead body 208 to the
implantable pulse generator 210. The implantable pulse generator
210 contains control circuitry that receive cardiac signals sensed
with the electrodes and generates pacing pulses to be delivered
with the electrodes. The electronic control circuitry within the
implantable pulse generator 210 also analyzes and detects certain
types of arrhythmias and provides pacing pulses, cardioversion
and/or defibrillation pulses to correct for them.
[0032] The apparatus 200 further includes a second lead 226, where
the second lead 226 has a lead body 230 having a proximal end 232,
a distal end 234 and includes a lead connector 235 having one or
more connector terminals. In one embodiment, examples of the lead
connector 235 and connector terminals include, but are not limited
to, LV-1, IS-1 UNI or IS-1 BI. Other lead connectors and connector
terminals are possible.
[0033] The second lead 226 further includes a first left
ventricular electrode 236 and a second left ventricular electrode
238, where both the first and second left ventricular electrodes
236 and 238 are adapted to be positioned adjacent the left
ventricle 240 via the coronary vasculature. In one embodiment, the
first and second left ventricular electrodes 236 and 238 are
pacing/sensing electrodes, where the first electrode 236 and the
second electrode 238 are ring electrodes that either completely or
partially encircles lead body 230. Alternatively, the second
electrode 238 is a tip electrode positioned at the distal end 234
of the lead 226.
[0034] In one embodiment, the second lead 226 is adapted to be
inserted through the coronary sinus vein 242 and through the great
cardiac vein, or other coronary branch vein, to position the
ventricular electrodes 236 and 238 adjacent the left ventricle 240
of the heart 216. In an alternative embodiment, the second lead 226
is an epicardial lead, where the electrodes on the lead 226 are
positioned epicardially adjacent the left ventricle of the
heart.
[0035] The lead 226 is releasably attached to the implantable pulse
generator 210, where the connector terminals couple the ventricular
electrodes 236 and 238 via lead conductors to the electronic
control circuitry within the implantable pulse generator 210. The
control circuitry within the implantable pulse generator 210
receives cardiac signals sensed through the use of the electrodes
236 and 238 and generates pacing pulses to be delivered through the
use of the electrodes.
[0036] Sensing and pacing with electrodes 218, 219, 220, 236 and
238 and the housing of the implantable pulse generator 210 is a
programmable feature of the control circuitry within the pulse
generator 210. In one embodiment, programming the sensing and
pacing vectors is accomplished through the use of a medical device
programmer 239. The medical device programmer 239 is used to
program specific pacing and sensing vectors that use one or both
electrodes 236 and 238 in conjunction with different combinations
of electrodes 218, 219, 220 and the housing of the implantable
pulse generator 210.
[0037] In one embodiment, either of the ventricular electrodes 236
or 238 is used in unipolar sensing and pacing between the electrode
(236 or 238) and the housing 210. Examples of these sensing and
pacing vectors are shown generally at 250. In one example, the
control circuitry of the pulse generator 210 is programmed to
switch from unipolar sensing and pacing between one of the two
electrodes 236 or 238 and the housing to unipolar sensing and
pacing between the other electrode of 236 or 238 and the housing.
In an additional embodiment, both ventricular electrodes 236 and
238 are used in unipolar sensing and pacing between the electrodes
236 and 238 and the housing 210. Alternatively, a bipolar sensing
and pacing vector occurs between the two electrodes 236 and 238,
where either 236 or 238 is the anode and the other electrode is the
cathode.
[0038] In one embodiment, the electrodes 236 and 238 are used in
sensing and pacing between the left and right ventricles of the
heart. For example, one or both of the two electrodes 236 or 238 is
used to sense cardiac signals and provide pacing pulses between the
electrode(s) 236 and/or 238 and the first supraventricular
electrode 220. In one embodiment, this pacing sensing vector is
shown generally at 252. Alternatively, one or both of the two
electrodes 236 and/or 238 is used to sense cardiac signals and
provide pacing pulses between the electrode(s) 236 and/or 238 and
the first right ventricular electrode 218. In one embodiment, this
pacing sensing vector is shown generally at 254. In addition, one
or both of the two electrodes 236 and/or 238 is used to sense
cardiac signals and provide pacing pulses between the electrode(s)
236 and/or 238 and the second right ventricular electrode 219. In
one embodiment, this pacing sensing vector is shown generally at
255. Pacing and sensing vectors 252, 254 and 255 are referred to
herein as "extended" bipolar pacing/sensing vector, as the pacing
and sensing occurs between implanted electrodes across a larger
portion of the heart than is typical with a traditional bipolar
pacing/sensing vector.
[0039] In one embodiment, electrodes 218, 219, 220, 236 and 238 are
created from either platinum, platinum-iridium alloys or alloys
which can include cobalt, iron, chromium, molybdenum, nickel and/or
manganese. In addition, the second right ventricular electrode 219
and the second left ventricular electrode 238 are porous
electrodes. Alternatively, the second right ventricular electrode
219, the first left ventricular electrode 236, and the second left
ventricular electrode 238 are ring electrodes that either partially
or fully encircle their respective lead bodies, 208 or 230, as
previously discussed. In addition, the second right ventricular
electrode 219 further includes a helical screw for positive
fixation of the lead 204.
[0040] In one embodiment, the lead bodies 208 and 230 are formed of
a biocompatible polymer such as silicone rubber and/or
polyurethane. The lead bodies 208 and 230 further includes one or
more lumens which are adapted to receive a stylet, or guidewire,
for guiding and implanting the leads 204 and 226. In one
embodiment, the lead bodies 208 and 230 include a lumen that
extends from an opening at the proximal end of the lead to the
distal end of the lead to allow the lead to be controlled through
the use of the stylet, or guidewire. In one embodiment, the stylet
lumen is formed from a lead conductor extending from the connector
terminal and the proximal end of the lead, 204 and 226 to a distal
most electrode on the lead (e.g., the second right ventricular
electrode 219 and the second left ventricular electrode 238).
[0041] FIG. 3 shows one embodiment of control circuitry 300, as
previously mentioned, for an implantable pulse generator 302. In
the present embodiment, the implantable pulse generator 302 is
adapted to receive the first and second leads (e.g., 204 and 226),
as discussed.
[0042] The control circuitry 300 is contained within a hermetically
sealed housing 304. The housing 304 is electrically conductive and
acts as a reference electrode in unipolar pacing and sensing, as
will be described below. The pulse generator 302 further includes a
connector block 306 that receives the connector terminals of the
cardiac leads, such as 204 and 226. The connector block 306
includes contacts 308, 310, 312, 314 and 316 that connect
electrodes 220, 218, 219, 238 and 236, respectively, to sense
amplifiers 320 and 326.
[0043] In one embodiment, an output from amp 320 is shown coupled
to a right ventricular activity sensor 328 to allow for a bipolar
cardiac signal to be sensed from the right ventricle 214 (FIG. 2)
between the first right ventricular electrode 218 and the second
right ventricular electrode 219 via switch matrix 332. In this
embodiment, the extended bipolar cross chamber sensing is
accomplished by the controller 340 configuring the switch matrix
332 such that the left ventricular activity sensor 334 receives an
extended bipolar cardiac signal sensed between the second left
ventricular electrode 238 and the first right ventricular electrode
218. Alternatively, the left ventricular activity sensor 334
receives the extended bipolar cardiac signal sensed between the
first left ventricular electrode 236 and the first right
ventricular electrode 218. The left ventricular activity sensor 334
also receives extended bipolar cardiac signal sensed between the
second left ventricular electrode 238 and the first
supraventricular electrode 220, in addition to an extended bipolar
cardiac signal sensed between the first left ventricular electrode
236 and the first supraventricular electrode 220. In addition, the
left ventricular activity sensor 334 receives the extended bipolar
cardiac signal sensed between the first and second left ventricular
electrodes 236 and 238 and the first right ventricular electrode
218. Alternatively, the left ventricular activity sensor 334
receives the extended bipolar cardiac signal sensed between the
first and second left ventricular electrodes 236 and 238 and the
second right ventricular electrode 219. Which combination of
extended bipolar cardiac signals are sensed depends upon the
sensing vectors programmed into the switch matrix 332 by control
circuitry 300. FIG. 3 also shows the output from amp 326 coupled to
a left ventricular activity sensor 334 to allow for a bipolar
cardiac signal to be sensed from the left ventricle 240 (FIG. 2)
between the first and second left ventricular electrodes 236 and
238.
[0044] The control circuitry 300 further includes a controller 340,
where the controller 340 receives the cardiac signals from the
sensing circuits 328 and 334 and analyzes the cardiac signals to
determine when and if to deliver electrical energy pulses to the
heart. In one embodiment, the controller 340 is a microprocessor,
however, other circuitry under the control of software and/or
firmware may be used as the controller 340.
[0045] In one embodiment, the controller 340 implements one or more
analysis protocols stored in a memory 344 to analyze one or more of
the sensed cardiac signals and to provide pacing, cardioversion
and/or defibrillation therapy to one or more chambers of the heart
under certain predetermined conditions. Memory 344 is also used to
store one or more sensed cardiac signals to be downloaded to a
medical device programmer 348 for analysis. In one embodiment, the
control circuitry 300 communicates with the medical device
programmer 348 through a receiver/transmitter 350, where cardiac
signals, programs and operating parameters for the programs for the
implantable medical device are transmitted and received through the
use of the programmer 348 and the receiver/transmitter 350. Power
for the control circuitry is supplied by a battery 354.
[0046] The controller 340 further controls a pace output circuit
360 and a defibrillation output circuit 364 to provide pacing,
cardioversion and/or defibrillation therapy to one or more chambers
of the heart under certain predetermined conditions. In one
embodiment, the pace output circuit 360 is coupled to contacts 308,
310, 312, 314 and 316 via switch matrix 332 to allow for bipolar
pacing between electrodes 218 and 219, and extended bipolar pacing
between electrodes 236 and/or 238 and 218, 219 or 220, as
previously described. In an additional, extended bipolar pacing and
sensing occurs between electrodes 236 and 238, electrically coupled
in common, and electrode 218, 219 or 220. In one embodiment,
electrodes 236 and/or 238 are the cathode and electrodes 218, 219
and/or 220 are used as the anode in the extended bipolar pacing and
sensing. Alternatively, electrodes 236 and/or 238 are the anode and
electrodes 218, 219 and/or 220 are used as the cathode in the
extended bipolar pacing and sensing. In an additional embodiment,
when bipolar pacing occurs between electrodes 218 and 219,
electrode 218 is the cathode and electrode 219 is the anode.
[0047] In addition to the extended bipolar sensing and pacing,
electrode 236 and/or 238 are used in conjunction with the
conductive housing 304 of the implantable pulse generator to allow
for unipolar sensing and pacing between either of electrodes 236 or
238 and the housing 304. In an additional embodiment, the described
polarity of the electrodes used in the bipolar pacing and sensing
is reversed to allow for additional options in providing therapy to
a patient.
[0048] The different combinations of the pacing and sensing vectors
are programmable features that are selected and implemented in the
implantable pulse generator 302 through the use of the medical
device programmer 348. Thus, different combinations of pacing and
sensing vectors (as described above) are selected and programmed
based on each patient's specific needs. In addition, the
programmable nature of the sensing and pacing vectors described
herein allows for one or more of the sensing and/or pacing vectors
to be altered based on sensed cardiac signals and the response to
the pacing pulses delivered to the patient's heart.
[0049] FIG. 4 shows an additional embodiment of an apparatus 400
according to the present subject matter. In FIG. 4, the apparatus
400 includes a first lead 204, as described above for FIG. 2. FIG.
4 further includes a second lead 404, where the second lead 404
includes a plurality of electrodes. In one embodiment, the second
lead 404 includes a first left ventricular electrode 408, a second
left ventricular electrode 412 and a third left ventricular
electrode 416.
[0050] Lead 404 includes a lead connector 418 having connector
terminals for coupling the electrodes 408, 412 and 416 via
conductors within the lead body to the control circuitry within the
implantable pulse generator 420. In one embodiment, the electrodes
408, 412 and 416 are adapted to be positioned adjacent the left
ventricle 430 via the coronary vasculature. In one embodiment, the
first, second and third left ventricular electrodes 408, 412 and
416 are pacing/sensing electrodes, where the electrodes are all
ring electrodes that either completely or partially encircles lead
body, or are a combination of ring electrodes and distal tip
electrode positioned at the distal end of the lead 404. In
addition, the lead body of the lead 404 forms a helix that is
adapted to allow for the electrodes 408, 412 and 416 to better
contact the cardiac tissue adjacent the left ventricle of the
heart.
[0051] In one embodiment, the first and second left ventricular
electrodes 408 and 412 are electrically connected in common, where
pacing and sensing signals occur between combinations of the first
and second left ventricular electrodes 408 and 412, in common, and
the third left ventricular electrode 416. In an alternative
embodiment, the first and second left ventricular electrodes 408
and 412 both have the same electrical polarity (e.g., anode or
cathode), but are not electrically coupled in common. Thus, each
electrode 408 and 412 is electrically isolated, but has the same
electrical polarity. The control circuitry within the implantable
pulse generator 420 then controls each electrode for delivering
pacing signals and sensing cardiac signals to the heart. In one
embodiment, this allows the control circuitry to individually
adjust the output of one or both the electrodes 408 and 412 based
on the pacing threshold of the patient.
[0052] In an additional embodiment, the control circuitry is
programmable to select and switch between sensing unipolar cardiac
signal and/or delivering unipolar pacing pulses between each
electrodes 408, 412 or 416 and the housing of the implantable pulse
generator 420. Additionally, the control circuitry is also
programmable to select and switch between sensing extended bipolar
signals and/or delivering extended bipolar pacing pulses between
each electrodes 408, 412 or 416 and either the first right
ventricular electrode 218, the second right ventricular electrode
219 or the first supraventricular electrode 220.
[0053] FIG. 5 shows an additional embodiment of an apparatus 500
according to the present subject matter. In FIG. 5, the apparatus
500 includes the first lead 104, as described above for FIG. 1, and
lead 226, as described above for FIG. 2. This embodiment allows for
combinations of electrodes 118, 120 of the first lead 104 and
electrodes 236 and 238 of the second lead 226 to be programmed to
sense cardiac signals and/or deliver pacing pulses between any
number of electrode combinations. For example, extended bipolar
cardiac signals are sensed between and/or pacing pulses are
delivered between electrode 236 and electrode 118 and/or 120,
and/or extended bipolar cardiac signals are sensed between and/or
pacing pulses are delivered between electrode 238 and electrode 118
and/or 120. The control circuitry of the implantable pulse
generator 504 is programmable to select and switch between sensing
unipolar cardiac signal and/or delivering unipolar pacing pulses
between each electrodes 118, 120, 236 or 238 and the housing of the
implantable pulse generator 504. Additionally, the control
circuitry is also programmable to select and switch between sensing
unipolar cardiac signal and/or delivering unipolar pacing pulses
between each electrodes 236 and 238 and either electrode 118 or
120.
[0054] In an additional embodiment, the connector blocks of any of
the implantable pulse generators described above can further
include a reference electrode for use in sensing unipolar cardiac
signals and delivering unipolar pacing pulses between any of the
aforementioned electrodes (e.g., 118, 120, 218, 219, 220, 236, 238,
408, 412 or 416). An example of the connector block electrode is
shown in FIG. 5 at 510.
[0055] FIG. 6 shows one embodiment of a method 600 according to one
aspect of the present subject matter. At 610, a first cardiac lead
having at least a first supraventricular electrode is implanted
within a heart. In one embodiment, the first supraventricular
electrode is positioned within the right atrium of the heart and/or
a major vein leading to the right atrium. At 620, a second cardiac
lead having at least a first left ventricular electrode and a
second left ventricular electrode is implanted within a heart. In
one embodiment, the first and second left ventricular electrodes
are positioned in a left ventricular region of the heart.
[0056] Specific examples of the first supraventricular electrode
and the first and second left ventricular electrodes were presented
above. These examples, however, are not intended to be limiting and
different examples of the first supraventricular electrode and the
first and second left ventricular electrodes are possible. These
additional examples include, but are not limited to, the first
supraventricular electrode taking the form of a pacing/sensing
electrode, such as a ring electrode. Additionally, one or both of
the left ventricular electrodes can take the form of a coil
electrode that can be used in conjunction with any of the
aforementioned structures for the first supraventricular or
ventricular electrodes.
[0057] At 630, pacing pulse vectors and sensing vectors are
programmed between one or more of the first left ventricular
electrode and the second left ventricular electrode, and the first
supraventricular electrode in the right atrial region. At 640,
pacing pulses are delivered between the first and/or second left
ventricular electrode in the left ventricular region and the first
supraventricular electrode in the right atrial region, according to
the programmed pacing pulse vectors. In one embodiment, the first
and/or second left ventricular electrode is used as the cathode,
while the first supraventricular electrode is used as the anode. In
an alternative embodiment, the first supraventricular electrode is
used as the cathode, while the first and/or the second left
ventricular electrode is used as the anode.
[0058] In addition to providing pacing pulses between the first
and/or second left ventricular electrode and the first
supraventricular electrode, sensing vectors between the first left
ventricular electrode and/or the second left ventricular electrode,
and the first supraventricular electrode are sensed at 650
according to the programmed sensing vector. In one embodiment, the
cardiac signal is sensed where the first and/or second left
ventricular electrode is an anode and the first supraventricular
electrode is a cathode. In an alternative embodiment, the cardiac
signal is sensed where the first supraventricular electrode is an
anode and the first and/or second left ventricular electrode is a
cathode. In an additional embodiment, the housing of an implantable
pulse generator is conductive and is used in an electrode in common
with the first supraventricular electrode, as previously
discussed.
[0059] FIG. 7 shows one embodiment of a method 700 according to one
aspect of the present subject matter. At 710, a first cardiac lead
having at least a right ventricular electrode is implanted within a
heart. In one embodiment, the right ventricular electrode is either
a defibrillation electrode, such as the first right ventricular
electrode 218, or a pace/sense electrode, such as the second right
ventricular electrode 219. These examples, however, are not
intended to be limiting and different examples of the right
ventricular electrode are possible. In one embodiment, the right
ventricular electrode is positioned within the right ventricle of
the heart.
[0060] At 720, a second cardiac lead having at least a first left
ventricular electrode and a second left ventricular electrode is
implanted within a heart. In one embodiment, the first and second
left ventricular electrodes are positioned in a left ventricular
region of the heart. In one embodiment, the first and second left
ventricular electrodes are as previously described. These examples,
however, are not intended to be limiting and different examples of
the first and second left ventricular electrodes are possible. For
example, one or both of the left ventricular electrodes can take
the form of a coil electrode that can be used in conjunction with
any of the aforementioned structures for the supraventricular or
ventricular electrodes.
[0061] At 730, pacing pulse vectors and sensing vectors are
programmed between one or more of the first and second left
ventricular electrodes, and the right ventricular electrode. At
740, pacing pulses are delivered between the first and/or second
left ventricular electrode and the right ventricular electrode,
according to the programmed pacing pulse vectors. In one
embodiment, the first and/or second left ventricular electrode is
used as the cathode, while the right ventricular electrode is used
as the anode. In an alternative embodiment, the right ventricular
electrode is used as the cathode, while the first and/or the second
left ventricular electrode is used as the anode.
[0062] In addition to providing pacing pulses between the first
and/or second left ventricular electrode and the right ventricular
electrode, sensing vectors between one, or both, of the first and
second left ventricular electrodes and the right ventricular
electrode are sensed at 750 according to the programmed sensing
vector. In one embodiment, the cardiac signal is sensed where the
first and/or second left ventricular electrode is an anode and the
right ventricular electrode is a cathode. In an alternative
embodiment, the cardiac signal is sensed where the right
ventricular electrode is an anode and the first and/or second left
ventricular electrode is a cathode. In an additional embodiment,
the housing of an implantable pulse generator is conductive and is
used in an electrode in common with the right ventricular
electrode, as previously discussed.
[0063] FIG. 8 shows one embodiment of a method 800 according to one
aspect of the present subject matter. At 810, a first cardiac lead
having at least a first supraventricular electrode and a first
ventricular electrode is implanted within a heart. In one
embodiment, the first supraventricular electrode is positioned
within the right atrium of the heart, while the first ventricular
electrode is positioned within the right ventricle of the heart. In
one embodiment, the right ventricular electrode is either a
defibrillation electrode, such as the first right ventricular
electrode 218, or a pace/sense electrode, such as the second right
ventricular electrode 219. These examples, however, are not
intended to be limiting and different examples of the right
ventricular electrode are possible. At 820, a second cardiac lead
having at least a first left ventricular electrode and a second
left ventricular electrode is implanted within a heart. In one
embodiment, the first and second left ventricular electrodes are
positioned in a left ventricular region of the heart.
[0064] Specific examples of the first supraventricular and
ventricular electrodes and the first and second left ventricular
electrodes were presented above. These examples, however, are not
intended to be limiting and different examples of the first
supraventricular and ventricular electrodes and the first and
second left ventricular electrodes are possible. These additional
examples include, but are not limited to, the first
supraventricular or ventricular electrode taking the form of a
pacing/sensing electrode, such as a ring electrode. Additionally,
one or both of the left ventricular electrodes can take the form of
a coil electrode that can be used in conjunction with any of the
aforementioned structures for the first supraventricular or
ventricular electrodes.
[0065] At 830, pacing pulse vectors and sensing vectors are
programmed between one or more of the first left ventricular
electrode and/or the second left ventricular electrode, and the
first supraventricular electrode in the right atrial region and the
right ventricular electrode in the right ventricle. At 840, pacing
pulses are delivered between either the first and/or second left
ventricular electrode and the first supraventricular electrode
and/or the first right ventricular electrode, according to the
programmed pacing pulse vectors. In one embodiment, the first
and/or second left ventricular electrode is used as the cathode,
while the first supraventricular and/or the right ventricular
electrode is used as the anode. In an alternative embodiment, the
first supraventricular and/or right ventricular electrode is used
as the cathode, while the first and/or the second left ventricular
electrode is used as the anode.
[0066] In addition to providing pacing pulses between the first
and/or second left ventricular electrode and the first
supraventricular electrode and/or right ventricular electrode,
sensing vectors between one or both of the first and/or second left
ventricular electrodes, and the first supraventricular and/or the
right ventricular electrode are sensed at 850 according to the
programmed sensing vector. In one embodiment, the cardiac signal is
sensed where the first and/or second left ventricular electrode is
an anode and the first supraventricular electrode and/or the right
ventricular electrode is a cathode. In an alternative embodiment,
the cardiac signal is sensed where the first supraventricular
electrode and/or the right ventricular electrode is an anode and
the first and/or second left ventricular electrode is a cathode. In
an additional embodiment, the housing of an implantable pulse
generator is electrically conductive and used as an electrode in
common with the first supraventricular electrode and/or the right
ventricular electrode, as previously discussed.
[0067] FIG. 9 shows one embodiment of a method 900 according to an
additional aspect of the present subject matter. At 910, a first
cardiac lead having at least a first right ventricular electrode
and a second right ventricular electrode is implanted within a
heart. In one embodiment, the first and second right ventricular
electrodes are positioned within the right ventricle of the heart.
Specific examples of the first and second right ventricular
electrodes were presented above, where the first right ventricular
electrode is a defibrillation coil electrode positioned in a right
ventricular region, and the second right ventricular electrode is a
pacing/sensing electrode located at or near the distal tip of the
lead and positioned in an apex of the right ventricular region. At
920, a pacing level pulse is delivered from a first ventricular
defibrillation electrode as a cathode to a first ventricular
pacing/sensing electrode as an anode.
[0068] FIG. 10 shows an additional embodiment of control circuitry
1000, as previously mentioned, for an implantable pulse generator
1002. In the present embodiment, the implantable pulse generator
1002 is adapted to receive the first and second leads (e.g., 204
and 226, 204 and 404, 104 and 226), as previously discussed.
[0069] The control circuitry 1000 is contained within a
hermetically sealed housing 1004. The housing 1004 is electrically
conductive and acts as a reference electrode in unipolar pacing and
sensing, as will be described below. The pulse generator 1002
further includes a connector block 1006 that receives the connector
terminals of the cardiac leads, such as 204 and 226, 204 and 404,
or 104 and 226. In one embodiment, the connector block 1006
includes contacts 1008, 1010, 1012, 1014 and 1016 that connect
electrodes 220, 218, 219, 238 and 236, respectively, to sense
amplifiers 1020, 1022, 1024 and 1026.
[0070] In one embodiment, an output from amp 1020 is shown coupled
to a right ventricular activity sensor 1028 to allow for a bipolar
cardiac signal to be sensed from the right ventricle 214 (FIG. 2)
between the first right ventricular electrode 218 and the second
right ventricular electrode 219. In addition, an output from amps
1022 and 1024 is shown coupled to an extended bipolar cross chamber
sensor 1030. In this embodiment, the extended bipolar cross chamber
sensor 1030 receives an extended bipolar cardiac signal sensed
between the second left ventricular electrode 238 and the first
right ventricular electrode 218. Alternatively, the extended
bipolar cross chamber sensor 1030 receives the extended bipolar
cardiac signal sensed between the first left ventricular electrode
236 and the first right ventricular electrode 218. The extended
bipolar cross chamber sensor 1030 also receives extended bipolar
cardiac signal sensed between the second left ventricular electrode
238 and the first supraventricular electrode 220, in addition to an
extended bipolar cardiac signal sensed between the first left
ventricular electrode 236 and the first supraventricular electrode
220. In addition, the extended bipolar cross chamber sensor 1030
receives the extended bipolar cardiac signal sensed between the
first and second left ventricular electrodes 236 and 238 and the
first right ventricular electrode 218. Alternatively, the extended
bipolar cross chamber sensor 1030 receives the extended bipolar
cardiac signal sensed between the first and second left ventricular
electrodes 236 and 238 and the second right ventricular electrode
219. Which combination of extended bipolar cardiac signals are
sensed depends upon the sensing vectors programmed into the control
circuitry 1000. FIG. 10 also shows an output from amp 1026 coupled
to a left ventricular activity sensor 1034 to allow for a bipolar
cardiac signal to be sensed from the left ventricle 240 (FIG. 2)
between the first and second left ventricular electrodes 236 and
238.
[0071] The control circuitry 1000 further includes a controller
1040, where the controller 1040 receives the cardiac signals from
the sensing circuits 1028, 1030 and 1034 and analyzes the cardiac
signals to determine when and if to deliver electrical energy
pulses to the heart. In one embodiment, the controller 1040 is a
microprocessor, however, other circuitry under the control of
software and/or firmware may be used as the controller 1040.
[0072] In one embodiment, the controller 1040 implements one or
more analysis protocols stored in a memory 1044 to analyze one or
more of the sensed cardiac signals and to provide pacing,
cardioversion and/or defibrillation therapy to one or more chambers
of the heart under certain predetermined conditions. Memory 1044 is
also used to store one or more sensed cardiac signals to be
downloaded to a medical device programmer 1048 for analysis. In one
embodiment, the control circuitry 1000 communicates with the
medical device programmer 1048 through a receiver/transmitter 1050,
where cardiac signals, programs and operating parameters for the
programs for the implantable medical device are transmitted and
received through the use of the programmer 1048 and the
receiver/transmitter 1050. Power for the control circuitry is
supplied by a battery 1054.
[0073] The controller 1040 further controls a pace output circuit
1060 and a defibrillation output circuit 1064 to provide pacing,
cardioversion and/or defibrillation therapy to one or more chambers
of the heart under certain predetermined conditions. In one
embodiment, the pace output circuit 1060 is coupled to contacts
1008, 1010, 1012, 1014 and 1016 to allow for bipolar pacing between
electrodes 218 and 219, and extended bipolar pacing between
electrodes 236 and/or 238 and 218, 219 or 220, as previously
described. In an additional, extended bipolar pacing and sensing
occurs between electrodes 236 and 238, electrically coupled in
common, and electrode 218, 219 or 220. In one embodiment,
electrodes 236 and/or 238 are the cathode and electrodes 218, 219
and/or 220 are used as the anode in the extended bipolar pacing and
sensing. Alternatively, electrodes 236 and/or 238 are the anode and
electrodes 218, 219 and/or 220 are used as the cathode in the
extended bipolar pacing and sensing. In an additional embodiment,
when bipolar pacing occurs between electrodes 218 and 219,
electrode 218 is the cathode and electrode 219 is the anode.
[0074] In addition to the extended bipolar sensing and pacing,
electrode 236 and/or 238 are used in conjunction with the
conductive housing 1004 of the implantable pulse generator to allow
for unipolar sensing and pacing between either of electrodes 236 or
238 and the housing 1004. In an additional embodiment, the
described polarity of the electrodes used in the bipolar pacing and
sensing is reversed to allow for additional options in providing
therapy to a patient.
[0075] The different combinations of the pacing and sensing vectors
are programmable features that are selected and implemented in the
implantable pulse generator 1002 through the use of the medical
device programmer 1048. Thus, different combinations of pacing and
sensing vectors (as described above) are selected and programmed
based on each patient's specific needs. In addition, the
programmable nature of the sensing and pacing vectors described
herein allows for one or more of the sensing and/or pacing vectors
to be altered based on sensed cardiac signals and the response to
the pacing pulses delivered to the patient's heart.
[0076] In addition to the apparatus and methods described for
providing pacing and sensing across ventricular regions of the
heart, the present subject matter can also be used in a system
having electrodes implanted in and around the supraventricular
region of the heart. So, the present subject matter could be used
to sense and pace bipolarly across the right and left atrium of the
heart.
[0077] In addition to the apparatus and methods for providing
pacing and sensing across the regions of the heart using two left
ventricular electrodes, the present subject matter can also use a
cardiac lead having a plurality of left ventricular electrodes,
such as those shown and described in the example of FIG. 4.
[0078] It is to be understood that the above description is
intended to be illustrative, and not restrictive. Many other
embodiments will be apparent to those of skill in the art upon
reading and understanding the above description. It should be noted
that embodiments discussed in different portions of the description
or referred to in different drawings can be combined to form
additional embodiments of the present invention. The scope of the
invention should, therefore, be determined with reference to the
appended claims, along with the full scope of equivalents to which
such claims are entitled.
* * * * *