U.S. patent application number 12/411033 was filed with the patent office on 2009-10-01 for robust high power and low power cardiac leads having integrated sensors.
This patent application is currently assigned to Medtronic, Inc.. Invention is credited to Thomas D. Brostrom, Scott J. Davis, Yaling Fan, Douglas D. Nippoldt, Richard J. O'Brien, Michael A. Schugt.
Application Number | 20090248107 12/411033 |
Document ID | / |
Family ID | 40599928 |
Filed Date | 2009-10-01 |
United States Patent
Application |
20090248107 |
Kind Code |
A1 |
Nippoldt; Douglas D. ; et
al. |
October 1, 2009 |
Robust High Power and Low Power Cardiac Leads Having Integrated
Sensors
Abstract
A lead of an implantable medical device system that includes a
sensor coupled to a lead body and extending from a proximal end to
a distal end, and a distal lead adaptor having a first arm
extending distally from the distal end of the sensor to a first arm
end, a second arm extending distally from the distal end of the
sensor to a second arm end, and a third arm extending between the
first arm end and the second arm end, wherein the first arm, the
second arm, and the third arm form an open portion. The sensor
includes a first portion extending from a top to a bottom, and from
a proximal end to a distal end, a second portion engaged against
the first portion and extending from a top to a bottom, the top of
the second portion extending from a proximal end to a distal end, a
first flange extending proximally relative to the proximal end of
the top of the second portion to a first flange end, and a second
flange extending distally relative to the distal end of the top of
the second portion to a second flange end, wherein the first flange
end is aligned with the proximal end of the first portion and the
second flange end is aligned with the distal end of the first
portion.
Inventors: |
Nippoldt; Douglas D.;
(Centerville, MN) ; Brostrom; Thomas D.; (Wayzata,
MN) ; O'Brien; Richard J.; (Hugo, MN) ;
Schugt; Michael A.; (Saint Paul, MN) ; Davis; Scott
J.; (Maple Grove, MN) ; Fan; Yaling; (Savage,
MN) |
Correspondence
Address: |
MEDTRONIC, INC.
710 MEDTRONIC PARKWAY NE
MINNEAPOLIS
MN
55432-9924
US
|
Assignee: |
Medtronic, Inc.
Minneapolis
MN
|
Family ID: |
40599928 |
Appl. No.: |
12/411033 |
Filed: |
March 25, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61207854 |
Mar 25, 2008 |
|
|
|
61207860 |
Mar 25, 2008 |
|
|
|
Current U.S.
Class: |
607/36 ;
607/119 |
Current CPC
Class: |
A61B 5/02152 20130101;
A61B 5/02158 20130101; A61B 2562/187 20130101; A61B 2562/0247
20130101; A61N 1/056 20130101 |
Class at
Publication: |
607/36 ;
607/119 |
International
Class: |
A61N 1/375 20060101
A61N001/375; A61N 1/05 20060101 A61N001/05 |
Claims
1. A lead of an implantable medical device system, comprising: an
elongated lead body; a sensor coupled to the lead body and
extending from a proximal end to a distal end; a distal lead
adaptor having a first arm extending distally from the distal end
of the sensor to a first arm end, a second arm extending distally
from the distal end of the sensor to a second arm end, and a third
arm extending between the first arm end and the second arm end,
wherein the first arm, the second arm, and the third arm form an
open portion, wherein the sensor comprises: a first portion
extending from a top to a bottom, and from a proximal end to a
distal end; a second portion engaged against the first portion and
extending from a top to a bottom, the top of the second portion
extending from a proximal end to a distal end; a first flange
extending proximally relative to the proximal end of the top of the
second portion to a first flange end; and a second flange extending
distally relative to the distal end of the top of the second
portion to a second flange end, wherein the first flange end is
aligned with the proximal end of the first portion and the second
flange end is aligned with the distal end of the first portion.
2. The lead of claim 1, further comprising a flexible member having
a proximal end formed to receive the first arm, the second arm, and
the third arm when the proximal end of the flexible member is
positioned against the proximal end of the sensor.
3. The lead of claim 2, further comprising a medical adhesive
positioned within the open portion formed by the first arm, the
second arm and the third arm, the medical adhesive adhering to a
silicone portion of the flexible member and forming an adhesive
wedge abutting the first arm, the second arm and the third arm to
prevent longitudinal movement of the sensor from the flexible
member.
4. The lead of claim 1, wherein the proximal end of the top of the
second portion extends a first length from the distal end of the
top of the second portion and the first flange end extends a second
length greater than the first length from second flange end.
5. The lead of claim 1, further comprising: a first coil extending
through a first lumen extending through the lead body to the
proximal end of the first portion; and a second coil extending
through a second lumen extending through the lead body and the
second portion.
6. The lead of claim 5, wherein the first coil is a communication
bus coil and the second coil is a torque coil.
7. The lead of claim 1, wherein the sensor comprises a pressure
sensor for sensing changes in pressure along the sensor.
8. The lead of claim 5, wherein the first lumen and the second
lumen are spaced apart to define a plane through a center axis
extending through the first and the second lumen, the center axis
being perpendicular to a longitudinal direction extending between
the proximal end and the distal end of the sensor.
9. An implantable medical device system, comprising: a device
housing; a lead having an elongated lead body and a connector to
electrically couple the lead to the housing; a sensor coupled to
the lead body and extending from a proximal end to a distal end; a
distal lead adaptor having a first arm extending distally from the
distal end of the sensor to a first arm end, a second arm extending
distally from the distal end of the sensor to a second arm end, and
a third arm extending between the first arm end and the second arm
end, wherein the first arm, the second arm, and the third arm form
an open portion, wherein the sensor comprises: a first portion
extending from a top to a bottom, and from a proximal end to a
distal end; a second portion engaged against the first portion and
extending from a top to a bottom, the top of the second portion
extending from a proximal end to a distal end; a first flange
extending proximally relative to the proximal end of the top of the
second portion to a first flange end; and a second flange extending
distally relative to the distal end of the top of the second
portion to a second flange end, wherein the first flange end is
aligned with the proximal end of the first portion and the second
flange end is aligned with the distal end of the first portion.
10. The implantable medical device system of claim 9, further
comprising a flexible member having a proximal end formed to
receive the first arm, the second arm, and the third arm when the
proximal end of the flexible member is positioned against the
proximal end of the sensor.
11. The implantable medical device system claim 10, further
comprising a medical adhesive positioned within the open portion
formed by the first arm, the second arm and the third arm, the
medical adhesive adhering to a silicone portion of the flexible
member and forming an adhesive wedge abutting the first arm, the
second arm and the third arm to prevent longitudinal movement of
the sensor from the flexible member.
12. The implantable medical device system claim 9, wherein the
proximal end of the top of the second portion extends a first
length from the distal end of the top of the second portion and the
first flange end extends a second length greater than the first
length from second flange end.
13. The implantable medical device system of claim 9, further
comprising: a first coil extending through a first lumen extending
through the lead body to the proximal end of the first portion; and
a second coil extending through a second lumen extending through
the lead body and the second portion.
14. The implantable medical device system of claim 13, wherein the
first coil is a communication bus coil and the second coil is a
torque coil.
15. The implantable medical device system of claim 9, wherein the
sensor comprises a pressure sensor for sensing changes in pressure
along the sensor.
16. The implantable medical device system of claim 13, wherein the
first lumen and the second lumen are spaced apart to define a plane
through a center axis extending through the first and the second
lumen, the center axis being perpendicular to a longitudinal
direction extending between the proximal end and the distal end of
the sensor.
Description
RELATED APPLICATION
[0001] This application claims the benefit of and priority to U.S.
Provisional Application Ser. No. 61/207,854, filed Mar. 25, 2008,
entitled, "Robust High Power and Low Power Cardiac Leads Having
Integrated Sensors," and U.S. Provisional Application Ser. No.
61/207,860, filed Mar. 25, 2008, entitled "Integrated Conductive
Pressure Sensor Capsule With Custom Molded Unitary Overlay, the
contents of which are incorporated by reference herein in their
entirety.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0002] Cross-reference is hereby made to the commonly assigned
related U.S. Applications, attorney docket number P0022633.02,
entitled "ROBUST HIGH POWER AND LOW POWER CARDIAC LEADS HAVING
INTEGRATED SENSORS", to Nippoldt and P0022633.04, entitled "ROBUST
HIGH POWER AND LOW POWER CARDIAC LEADS HAVING INTEGRATED SENSORS",
to Nippoldt, both incorporated herein by reference in their
entireties.
FIELD
[0003] The present disclosure relates to medical electrical leads
having one or more sensors coupled to a portion thereof which are
cooperatively designed with desired mechanical properties to reduce
strain on and signal artifacts from said one or more sensors.
BACKGROUND
[0004] Implantable cardiac leads having sensors in addition to
exposed coil, tip, and/or ring electrodes used to deliver
electrical stimulation to myocardial tissue and/or to sense
electrical cardiac activity as well as monitor one or more
physiologic parameters. Such leads include elongated electrical
conductors and are fabricated of a biocompatible polymeric
material, for example, polyurethane or silicone. Sensors have
previously been coupled to cardiac leads. Since the leads are
coupled to the myocardium they must possess flexibility and
strength. If the sensor or sensors is disposed near the distal end
of the lead the forces from the contractions can directly impinge
on the sensor surface possibly causing damage and signal artifacts.
If one or more electrodes are disposed distal to a sensor, one or
more electrical conductors must pass by or through the sensor
thereby increasing the complexity of the sensor assembly and
possibly changing the dimension of the sensor package. The
resulting package can thus have differing strain sensitivity that
adds signal artifacts and reduces long term stability of the sensor
disposed therein. A need thus exists for a cooperatively designed
sensor packaging and lead body that increases mechanical
reliability, operating life and improves long term sensor
stability.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIGS. 1A-1B are plan views of a medical electrical lead
according to embodiments of the disclosure.
[0006] FIG. 1C is a plan view of a medical electrical lead
according to an embodiment of the disclosure.
[0007] FIG. 1D is a schematic diagram of an implantable medical
device system utilizing a pressure sensing lead according to an
embodiment of the disclosure.
[0008] FIG. 2 is a perspective view of a distal portion of a
pressure sensing lead according to an embodiment of the
disclosure.
[0009] FIG. 3 is a cross-sectional view of a portion of a lead body
wherein two major elongated lumens, a sensor lumen and a torque
coil lumen are spaced apart and disposed whereby they define a
plane which promotes a bending direction perpendicular to the
defined plane.
[0010] FIG. 4 is a cross-sectional view of the lumens depicted in
FIG. 3 and the accompanying components disposed therein; namely, a
sensor communication bus coil, a torque coil as well as two high
energy cables (SVC cable and RV coil) and a low energy pacing cable
(ring cable).
[0011] FIG. 5A is a side view of a sensor of a medical electrical
lead according to an embodiment of the disclosure.
[0012] FIG. 5B is a perspective view of the sensor of FIG. 5A.
[0013] FIGS. 6A, 6B and 6C depict alternate view of the sensor
depicted in FIGS. 5A and 5B; namely, an elevational side view, a
plan view and a cross-sectional view.
[0014] FIG. 7 is a perspective view illustrating the relatively
thicker back portion of the sensor wherein the back portion
includes two longitudinal bores for receiving an elongated
conductor and a torque coil, respectively.
[0015] FIG. 8 is a perspective view of a sensor according to an
embodiment of the disclosure.
[0016] FIG. 8A is a plan view of a proximal end of the sensor of
FIG. 8.
[0017] FIG. 9 is a perspective view of a distal end of a sensor
lead according to an embodiment of the disclosure.
[0018] FIG. 10 is a cross-sectional view of a distal end of a
sensor lead according to an embodiment of the disclosure.
[0019] FIG. 11 is a cross-sectional elevational view of an
embodiment of the lead body having just two coils and one separate
cable.
[0020] FIG. 12 is a cross-sectional elevational view of an
embodiment of the lead body having just a single sensor bus coil
and one separate cable.
[0021] FIG. 13 is a cross-sectional elevational view of an
embodiment of the lead body having just two coils and one separate
cable.
[0022] FIG. 14 is a cross-sectional elevational view of an
embodiment of the lead body having a flattened cross-sectional
appearance and two coils and three separate cables.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0023] In the following detailed description, references are made
to illustrative embodiments for methods and apparatus including
very small sensors coupled to medical electrical leads. This
disclosure provides enhanced mechanical resiliency to very small
sensors coupled to medical electrical leads that are cooperatively
designed and fabricated.
[0024] One of the challenges in placing small sensors on a cardiac
lead is to make sure that the sensor only responds to the desired
physical parameter. The heart is a dynamic environment and cardiac
leads flex as the heart beats. The flexing of the cardiac lead
transmits forces to a sensor placed on the lead and, if not managed
appropriately, will induce a strain-related output signal artifact
from the sensor. The disclosure is directed to a cooperative
cardiac lead and sensor assembly wherein the sensor package or
capsule is mechanically strengthened in at least one specific
bending axis. The lead is then designed and constructed so that the
lead has a desired bending orientation. This can be accomplished
via a variety of different ways. One is to attach or couple
different mechanical structures about the longitudinal axis of the
lead (e.g., a pair of parallel cables in one portion while coils
are used in another). Another is to form one or more lumens within
the lead body that cause the lead body to bend in the desired
direction (e.g., ovoid-shaped lumen or lumens, V- or U-shaped
lumens). Of course a combination of structure and lumen can be used
to achieve the desired bending characteristic(s) for the lead.
Also, one or more portions of the lead body can be selectively
managed with lumens and/or structures; for example, only the distal
portion or only the distal and intermediate portion and the
like.
[0025] The necessary electrical conductors for a given cardiac
application may, or may not, provide a preferred bending
orientation of the lead body that is compatible with the robust
axis of the sensor. According to the invention, lumens, cables or
the like can be introduced into the lead body to provide the sensor
lead with the optimum preferred bending axis.
[0026] In one embodiment a coaxial sensor communication coil (for
bidirectional communication) is disposed in a lumen parallel to
another similarly-sized cable (e.g., a torque coil used to advance
an active fixation coil for insertion into adjacent tissue) so that
the lead body is mechanically constrained in one dimension (i.e.,
laterally across the pair of coils) and not constrained in another
(i.e., longitudinally perpendicular to the coils). In another
embodiment, the lead body is pre-formed via a heat treatment or
annealing treatment on one or more sides so that the stiffened axis
of the sensor is aligned with the pre-formed bending direction of
the lead body. In lieu of or in addition to pre-forming or
pre-bending the lead body the biocompatible material of the lead
body can have a differing modulus so that it is essentially softer
on one side thereby causing the lead body to flex, or bend, toward
the softer side. In another embodiment, the lead body can be formed
so that it is not iso-diametric or circular in cross section, that
is, the lead body is designed to have a relatively flattened
cross-section.
[0027] The sensor package is then cooperatively designed so that it
has a mechanically robust axis aligned with the not constrained
bending direction of the lead body. In the case that a stylet or
wire needs to be advanced beyond the sensor package, a receiving
bore or partial bore needs to be designed in the package.
Accordingly, the package needs to be designed to accommodate the
bore and the related structural impact needs to be considered.
Thus, one aspect of the foregoing involves aligning the package so
that the lead body bends in the direction of maximum stiffness of
the package. In one embodiment an internal longitudinal torque coil
used for advancing a helical member at the distal tip of the lead
promotes fixation of the lead to tissue. Also a coaxial
communications bus couples to the sensor and these two relatively
major components of the lead body (i.e., the torque coil and the
communications bus) define a desired bending direction (in the
direction perpendicular to the plane of the two coils).
[0028] Another embodiment of the invention includes more than one
sensor coupled to the lead body. For example, a pair of pressure
sensors coupled so that one sensor is adapted to reside in the
right ventricle and one sensor is adapted to reside in the right
atrium. In a variation on this embodiment, both of the sensors are
designed according to the disclosure to have a mechanically robust
axis aligned with the not constrained bending direction of the lead
body to impart a desired bending direction associated with the
specific sensor, resulting in the lead body having two different
preferred bending directions. This aspect of the invention allows
each sensor to more likely have its sensing surface facing toward
the blood residing in its respective chamber and away from the
chamber tissue.
[0029] In one embodiment a medical electrical lead is provided that
includes an elongated lead body formed of a biocompatible material
that has a desired longitudinal bending direction in at least one
of a proximal end portion, an intermediate portion and a distal
portion. The lead body includes at least one elongated conductor
disposed within the lead body that couples to a physiologic sensor
coupled to the conductor and is adapted to measure a parameter and
provide a signal through said conductor. The sensor is disposed in
a biocompatible sensor package that possesses a longitudinal
strain-insensitive axis that aligns with the desired physical
bending direction of the lead body.
[0030] Thus, the disclosure provides methods and structures for
deliberately introducing design features in a lead body to create a
preferential bending direction to accommodate the most
strain-insensitive bending axis of a sensor or sensors coupled to
the lead. That is, the lead and sensor system can be cooperatively
designed to provide one or more axes of bending and enhanced
mechanical strength, respectively. Such a system can be fabricated
according to the invention without compromising the performance
characteristics of a manually deployable cardiac therapy delivery
lead.
[0031] FIGS. 1A-B are plan views of medical electrical leads
according to alternate embodiments of the present invention. FIG.
1A illustrates lead 10 including a lead body first portion 11, a
lead body second portion 12 and a sensor assembly 15 coupled in
between first portion 11 and second portion 12; first portion 11
includes a first high voltage defibrillation electrode 19 and
second portion 12 includes a second high voltage defibrillation
electrode 190 and a low voltage tip electrode 16. FIG. 1 B
illustrates lead 100 including a lead body first portion 110, a
lead body second portion 120 and sensor assembly 15 coupled in
between first portion 110 and second portion 120; in this
embodiment, first portion 110 includes first high voltage
defibrillation electrode 19 and a second high voltage
defibrillation electrode 191 while second portion includes a low
voltage ring electrode 17 and low voltage tip electrode 16. Any
appropriate low voltage and high voltage electrode designs known to
those skilled in the art may be incorporated into embodiments of
the present invention, therefore the present invention is not
limited to the forms of these electrodes illustrated in FIGS. 1A-B.
Although FIGS. 1A-B illustrate first portion 11, 110 including at
least one electrode, first lead body portions according alternate
embodiments of the present invention need not include any
electrodes. Furthermore, according to alternate embodiments, a
second lead body portion, i.e. portions 12, 120, may include one or
more fluid infusion ports positioned for example where tip
electrode 16 or ring electrode 17 are positioned.
[0032] FIGS. 1A-B further illustrate lead body first portion 11,
110 joined to a sensor connector leg 130, via a first transition
sleeve 13, and to electrode connector legs 140, via a second
transition sleeve 14; connector legs 130 and 140 are adapted to
electrically couple a sensor of sensor assembly 15 and electrodes
16, 17, 19 and 190/191, respectively to an IMD in a manner well
known to those skilled in the art.
[0033] FIG. 1C is a plan view of a medical electrical lead
according to an embodiment of the disclosure. As illustrated in
FIG. 1C, lead 25 may include a lead body portion 27 extending from
a connector 29 to a sensor 102 as described herein. Lead also
includes a ring electrode 35 distal to the sensor 102, a right
ventricular (RV) electrode 37 and a superior vena cava (SVC)
electrode 39 positioned proximal to the sensor 33. Connector 29 of
lead 25 includes a connector leg 41 having a connector ring 43 for
electrically coupling the sensor 102 to circuitry within an IMD
housing, and a second connector leg 45 having a first connector
ring 47, a second connector ring 49, a third connector ring 51 and
a fourth connector ring 53 for electrically coupling the SVC
electrode 39, RV electrode 37, ring electrode 33 a helical tip
electrode 16, respectively, to corresponding circuitry within IMD
housing via conductors (not shown) extending between the electrodes
and the connector rings.
[0034] FIG. 1D is a schematic diagram of an implantable medical
device system utilizing a pressure sensing lead according to an
embodiment of the disclosure. As illustrated in FIG. 1D, an
implantable medical device system 300 that utilizes sensor 102
includes any one of sensor leads described above, such as sensor
lead 25, for example, and an implantable medical device housing
302. Housing 302 contains circuitry (not shown) for operating the
implantable medical device, as is known in the art, and includes a
header 304 for receiving connector rings 43-53 to electrically
couple the lead 25, including sensor 102, to the circuitry
contained in housing in a known fashion.
[0035] FIG. 2 is a perspective view of a distal portion of a
pressure sensing lead according to an embodiment of the disclosure.
As illustrated in FIG. 2, a sensor 102 according to the embodiments
of the disclosure includes a sensor body 60 having sensor membrane
201 positioned within a cutout portion 61 of the sensor body 60.
The membrane 201 extends laterally between a first side 135 and a
second side 137, and extends longitudinally (perpendicular to the
lateral extension) between a first end 139 and a second end 141
distal along the lead body 27 relative to the first end 139.
[0036] Undesirable deflection of sensor membrane 201 of pressure
sensor 102 may occur as a result of fluctuations in the level of
pressure present in a cardiac chamber. In order to best sense such
deflections, minimize signal artifacts, and limit stress upon the
sensor 102, it is desirable to ensure that the membrane 201 sweeps
in the lateral direction extending between the first side 135 and
the second side 137 (along the axis defined by arrow 106), rather
than in the longitudinal direction extending between the first end
139 and the second end 141 when coupled to myocardial tissue.
[0037] Adjacent to the sensor 102 is optional pacing and sensing
ring electrode 113. Coupled to the sensor 102 is a relatively
flexible member 110 coupling from the ring electrode 113 to
optional extendable and retractable helix sub-assembly 108 used to
fixate the tip of lead 100 to adjacent myocardial tissue. A
proximal sensor lead portion 104 includes optional right
ventricular (RV) coil electrode 130' used for high energy
defibrillation therapy delivery. Proximal to the RV coil electrode
130' is an optional second pressure sensor 102' having a sensing
membrane 201'. Lead 100 may include an optional superior vena cava
(SVC) coil electrode can be coupled to the lead 100 proximal to the
second pressure sensor 102'.
[0038] Although not depicted in FIG. 2, within the lead body 27 in
the proximal sensor lead portion 104 a set of electrical conductors
reside within a multi-lumen structure. For example, if the sensor
lead 100 is designed only for sensing, two coils will extend at
least to the sensor 102. The first, a torque coil 129, resides in a
lumen and is used during implantation (to enhance the so-called
"pushability" of the lead 100). The second, a co-axial
communication bus coil 127 (see FIG. 4) resides in a different
lumen for carrying signals to and from the circuitry of sensor 102.
As noted above, the two coils can be used to establish a desired
bending direction for the body of the lead 100 and the sensor 102
(i.e., in a lateral direction extending between the first side 135
and the second side 137 of the sensor membrane 201). This desired
bending direction results from the slight compressive load placed
upon the lead 100 shortly after implantation.
[0039] In other configurations, for example if the sensor lead 100
is designed for sensing pressure and cardiac activity and/or pacing
a heart, then the torque coil used during implant can be
electrically coupled to the tip electrode (e.g., helix of helical
sub-assembly 108 ) and optionally another elongated cable-type
conductor can be routed to the ring electrode 113. In this
configuration, the desired bending direction remains the same due
to the two coils orientation relative to the sensor membrane
201.
[0040] Also depicted in FIG. 2 is an optional second sensor 102'
having a sensor membrane 201' which can have an arbitrary
orientation relative to sensor member 201, applying the principles
described and depicted herein. That is, in the event that the
second sensor 102' is intended to sense pressure within the right
atrium (RA), the relative orientation of the two sensors 102, 102'
can be different or changed during fabrication of the lead 100 to
promote a different lateral motion for the sensor 102' (as depicted
by arrow 106'). If the second sensor 102' is adapted to sense RA
pressures, then in addition to having lateral motion of the
membrane 201' relative to the lead 100, the membrane 201' should
face away from the nearest wall of the RA. Also, the second sensor
102' can utilize the same digital sensor protocol carried upon the
sensor communication bus as the first sensor 102.
[0041] FIG. 3 is a cross-sectional view of a portion of a lead body
104 wherein two major elongated lumens 111,112 (denoted as a sensor
bus lumen and a torque coil lumen) are spaced apart and disposed
whereby they define a plane through the center axis of each, which
promotes the desired bending direction, i.e., in a direction
extending laterally between the first side 135 and the second side
137 of the membrane 201, perpendicular to the longitudinal
direction extending between the first end 139 and the second end
141 of the membrane 201.
[0042] As depicted, the lead body portion 27 may also have one or
more additional smaller-diameter lumens 108, 114, 116 configured to
receive an SVC cable, an RV cable, and a ring electrode cable
lumen, respectively. The lead body 104 is sheathed in an overlay
tubing 120 and the penta-lumen is nominally fabricated of Silicone
(e.g., MED-4755 made by Nusil Technology of Carpinteria, Calif.).
As depicted, the major lumens 111, 112 are designed to promote the
desired bending direction (indicated generally by arrow 106 of FIG.
3).
[0043] FIG. 4 is a cross-sectional view of the lumens depicted in
FIG. 3 and the accompanying components disposed therein; namely, a
sensor communication bus coil 127 having an inner sensor bus cable
124 and an outer sensor bus coil 122, a torque coil 129 having an
optional covering 128, as well as two high energy cables (SVC cable
126 and RV cable 130) and a low energy pacing and sensing cable
(ring cable) 132. The sensor bus coil 122, the sensor bus cable
124, and the torque coil 129 define a plane through the axial
center of each, which promotes the desired bending direction
extending laterally between the first side 135 and the second side
137 of the membrane 201, perpendicular to the longitudinal
direction extending between the first end 139 and the second end
141 of the membrane 201.
[0044] FIGS. 5A and 5B depict an embodiment of a sensor package 200
designed and constructed out of titanium according to one form of
the disclosure. For example, sensor package 200 may be formed using
a suitable titanium alloy, such as Ti 6AI-4V, for example, although
other alloys and other materials could suffice. FIG. 5A is a
perspective view of the sensor package 200 and FIG. 5B is an
elevational side view of the sensor package 200 illustrating an
embodiment wherein a relatively thin membrane 201 is used to sense
pressure fluctuations on one side of the sensor package 200, and a
relatively thicker back housing portion 207 provides an axis of
relative stiffness to the sensor package 200 (which is generally
perpendicular to the sensor package 200 depicted in FIG. 5B (i.e.,
perpendicular to the drawing sheet). In practice the axis of
stiffness is designed so that it is aligned with providing the
desired lateral bending direction of the membrane 201 as that
provided by the twin coils described above (and other structures
and/or lumens described below in relation to FIGS. 11-14).
[0045] As illustrated in FIG. 5A and 5B, back housing portion 207
extends from a top portion 217 to a bottom portion 219, with a
proximal end 234 of the top portion 217 extending from a proximal
end 213 to a distal end 215. A first bore 204 is formed adjacent to
the top portion 217 in back housing portion 207 for receiving the
torque coil 129 so that the torque coil 129 extends through the
sensor 102 from the proximal end to the distal end of the sensor
102 so as to be parallel to the membrane 201.
[0046] Sensor 102 further includes a distal adapter 206 located at
the distal end of the sensor 102 that is utilized to mechanically
couple the distal end of the sensor 102 and a proximal end of the
flexible distal end portion 110 (depicted in FIG. 3) in a way to
further provide the above-described desired lateral bending
direction to the membrane 201, as described below. Sensor 102
further includes an integrated circuit 201'' adapted to at least of
one of convey signals and calculate pressure applied to the
membrane 201.
[0047] In addition to the back housing portion 207 and the distal
adaptor 206, sensor 102 includes a lead adapter 209 that is
designed to further provide the above-described desired lateral
bending direction to the membrane 201, as described below. In
particular, sensor capsule 200 includes a feedthrough adaptor 208.
A feedthrough pin 203 extends outward from the proximal end of the
sensor 102 and through the feedthrough adaptor 208. During the
connecting of the distal end 210 of the lead body to the sensor
102, a lead adaptor pin 205 located at the distal end 210 of the
lead body 100 is electrically connected to the feedthrough pin 203
to enable electrical connection of the inner sensor bus coil 124 of
the communication bus coil 127 via the sensor bus lumen 111 to the
sensor capsule 200.
[0048] FIGS. 6A, 6B and 6C depict alternate views of the sensor
package 200 depicted in FIGS. 5A and 5B; namely, an elevational
side view, a plan view and a cross-sectional view. The bores 202,
204 of relatively thicker back portion 207 and the generally
circular cross-sectional shape of the sensor 102 are depicted in
FIG. 6C. The proximal and distal adapter 209, 206 are also
depicted.
[0049] FIGS. 7 and 8 are perspective views of a sensor according to
an embodiment of the disclosure. FIG. 8A is a plan view of a
proximal end of the sensor of FIG. 8. In the embodiment of FIG. 7,
the relatively thicker back housing portion 207 of the sensor
package 200 includes two longitudinal bores 202, 204 for receiving
an elongated conductor coupled to a distal ring electrode 113 and a
torque coil 129, respectively (See FIGS. 1A-1C). The bores 202, 204
are depicted having an open longitudinal portion but such a portion
is not required to practice the foregoing (see FIG. 8). In fact,
the collar of the open portion of bores 202, 204 can extend
radially outward from a position approximately from the maximum
diameter of each respective bore. A portion of the pressure sensor
integrated circuit 201'' is also depicted in FIG. 7 disposed within
the package 200.
[0050] In the embodiment of FIG. 8, the relatively thicker back
housing portion 207 of the sensor package 200 includes only a
single longitudinal bore 204 for receiving a torque coil 129 that
extends to the tip electrode 16.
[0051] As illustrated in FIGS. 5, 7 and 8, a membrane portion 220
of sensor 102 includes the membrane 201 and sensor circuitry 201.
The membrane portion 220 extends from a top portion 222 to a bottom
portion 224, the top portion 222 having the cutout portion 61
formed therein for exposing the membrane 201 to changes in pressure
around the sensor 102. The membrane portion 220 extends from a
proximal end 226 to a distal end 230. The proximal end 226 is
located adjacent to a distal end 228 of the lead adaptor 209 and
the distal end 230 is located proximal and adjacent to a proximal
end 232 of the distal adaptor 206 of the sensor 102.
[0052] In addition, the bottom portion 219 of the back housing 207
includes a first flange 240 extending proximally relative to the
proximal end 213 of the top portion 217 of the back housing 207,
and a second flange 242 extending distally relative to the distal
end 215 of the top portion 217 of the back housing 207. The first
flange 240 extends proximally from the proximal end 213 of the back
housing 207 to a first flange end 236 positioned distal and
adjacent to the distal end 228 of the lead adaptor 209.
[0053] Similarly, the second flange 242 extends distally from the
distal end 215 of the back housing 207 to a second flange end 238
positioned proximal and adjacent to the proximal end 232 of the
distal adaptor 206 of the sensor 102. In this way, the top portion
217 of the back housing 207 extends a first length from the
proximal end 217 to the distal end 215, while the bottom portion
219 extends a second length, greater than the first length, from
the first flange end 236 to the second flange end 238. In addition,
the second length associated with the bottom portion 219 of the
back housing 207 is approximately equal to a length of the bottom
224 of the membrane portion 220 so that the bottom 224 of the
membrane portion 220 is positioned to be aligned with and adjacent
to the bottom 219 of the back housing 207, with the bore 204 for
receiving the torque coil 129 being aligned with the lead adaptor
209 along a plane 107 (see FIG. 4) extending through a center axis
275 of both the bore 204 and the lead adaptor 209 (the plane 107
being substantially perpendicular to the above-described desired
lateral direction) to promote the desired bending direction of the
membrane 201, described above. Both the membrane portion 220 and
the back housing 207 are semi-circular in shape to form the
substantially circular shape of the sensor 102.
[0054] FIG. 9 is a perspective view of a distal end of a sensor
lead according to an embodiment of the disclosure. As illustrated
in FIGS. 8 and 9, distal adaptor 206 extends from the proximal end
232 to a distal end 250, the proximal end 232 being positioned
adjacent to both the distal end 230 of membrane portion 220 and the
second flange end 238 of the back housing 207. Distal adaptor 206
includes a first arm 252 that ends distally from the proximal end
238 of distal adaptor 206 to a first arm end 254, and a second arm
256 that extends distally from the proximal end 238 of distal
adaptor 206 to a second arm end 258. A third arm 260 extends
between the first arm end 254 and the second arm end 258 so that
the first arm 252, the second arm 256, and the third arm 260 form
an open portion 262. The third arm 260 has a semi-circular shape
that conforms to the semi-circular shape of the distal end 230 of
the membrane portion 220 of the sensor 102.
[0055] FIG. 10 is a cross-sectional view of a distal end of a
sensor lead according to an embodiment of the disclosure. As
illustrated in FIGS. 8-10, a proximal end 264 of flexible member
110 is formed to receive the first arm 254, second arm 258 and
third arm 260 of the distal adaptor 206 when the proximal end 264
of the flexible member 110 is positioned against the proximal end
232 of the distal adaptor 206. Once arms 254, 258 and 260 are
positioned within the proximal end 264 of flexible member 110 and
the proximal end 232 of the distal adaptor is engaged against the
distal end 230 of the membrane portion 220 and the distal end 238
of the second flange 242 of the back housing 207, a medical
adhesive 268 is injected and backfilled within open portion 262 and
adheres to the silicone portion 270 of flexible member 110
positioned along the inner side 272 and the outer side 274 of the
arms 254, 258 and 260. As a result, by positioning the adhesive 268
within open portion 262 to be secured against the silicone portion
270 both along the inner side 272 and the outer side 274 of the
distal adaptor 206, an adhesive wedge is formed that engages
against an inner wall 277 formed by the first arm 254, the second
arm 258 and the third arm 260 that minimizes longitudinal movement
of the distal adaptor 206, thus securing the distal adaptor 206
within the flexible member 110.
[0056] FIG. 11 is a cross-sectional elevational view of an
embodiment of the lead body having just two coils and one separate
cable 132. One coil is the torque coil 129 which can be insulated
with an polymer-based material 128 (especially where the coil 129
passes through the bore 204 of the titanium sensor package 200. The
other coil is the sensor bus coil 122 having sensor bus cable 124
insulated from and located within the coil 122.
[0057] FIG. 12 is a cross-sectional elevational view of an
embodiment of the lead body having just a single sensor bus coil
122 and one separate cable 132. In addition, to increase
"pushability" and to increase the likelihood that the lead body
will bend in the desired direction, a pair of structure and/or
lumens 81, 83 can be disposed alongside at least a portion of the
coil 122. That is, one or both of the items 81, 83 tend to promote
bending of the lead in the desired direction. The items 81, 83 can
be coupled directly to sensor package 200 or can terminate proximal
of the package 200. The items 81, 83 can comprise one or more
elongated segments of resilient material, such a polymer or the
like.
[0058] FIG. 13 is a cross-sectional elevational view of an
embodiment of the lead body having just two coils and one separate
cable 132. In addition, to increase "pushability" and to increase
the likelihood that the lead body will bend in the desired
direction, a structure and/or lumen 85 can be disposed alongside at
least a portion of the coil 122, such as a U-shaped structure or
lumen depicted in FIG. 13. Of course, a variety of other shaped
structures of lumen shapes can be utilized to achieve the
advantages of the invention. That is, the item 85 tends to promote
bending of the lead in the desired direction. The item 85 can be
coupled directly to sensor package 200 or can terminate proximal of
the package 200. The item 85 can comprise one or more elongated
segments of resilient material, such a polymer or the like, or
alternating segments of material and open lumen space.
[0059] FIG. 14 is a cross-sectional elevational view of an
embodiment of the lead body having a flattened cross-sectional
appearance and two coils 122', 128' and three separate cables 126,
130, 132. As with prior embodiments, the coils tend to promote the
lead to bend in the desired direction. In addition, the flattened
cross-sectional shape of the lead body further encourages it to
bend as desired thereby reducing signal artifacts and promoting
operating stability of the pressure sensor and lead system.
[0060] It will be understood that specifically described
structures, functions and operations set forth in the
above-referenced patents can be practiced in conjunction with the
present invention, but they are not essential to its practice. It
is therefore to be understood, that within the scope of the
appended claims, the invention may be practiced otherwise than as
specifically described without actually departing from the spirit
and scope of the present invention. For example, the sensor could
comprise an accelerometer (single- or multi-axis) which for any of
a number of reasons might need to have reduced structure on one or
more sides thereof thus becoming susceptible to the objects solved
herein.
* * * * *