IMPLANTABLE HEART ASSIST DEVICES AND METHODS
Field of the Invention
The present invention generally relates to devices used to
physically support the heart and, alternatively, also actively assist the
pumping action of the heart.
Background of the Invention
The treatment of heart failure over the long term is a difficult
problem. At the same time, weak cardiac muscle function is becoming an
increasing problem. Patients are surviving longer and more patients are
surviving myocardial infarcts leading to a large pool of patients who are
inadequately served by current medical practice. Drug treatment to
increase the strength of mycardial contraction has been unsuccessful over
the long term. Recently, biventricular pacing (rather than the usual
univentricular pacing) has been tried and this offers some promise in
selected patients but is unlikely to solve the problem.
Devices will therefore remain the mainstay of treatment for
terminal heart failure. Conventional methods have been unable to inject
adequate energy into the cardiovascular system. Past attempts with the
Jarvic heart or other replacement systems have met with problems such as
failure due to thromboembolism. The patient is typically connected to a
bulky internal or external controller and power supply for the heart
replacement system. The inside of the artificial heart exposes a large
artificial surface area to the flow of blood and clots develop as a result.
These clots eventually break off and lodge in the brain leading to strokes or
resulting in ischemic injury to other body organs. It has also been
postulated that long-term exposure of blood to large artificial surfaces sets
up a chronic inflammatory reaction which may predispose the patient to
infection.
Currently, there are two major areas of development. A
simplified system involves cannulation of the left ventricle or atrium with a
tube-like structure and pumping of blood from this source into the aorta. A
blood propeller system is located within the tubing of this system. A drive
system powers the pump. The drive system can be located outside the
patient, or can be implanted within the patient. If implanted, energy may be
transmitted by induction coils from outside the body to the device. This
device requires considerable residual cardiac function to operate. The heart
must beat adequately to perform some function and usually only the left
ventricle is supported by the device. Thus, right ventricular function must
be adequate for survival.
The second and more complex pump is a totally implantable
heart. The patient's heart is entirely removed or both ventricles are
cannulated and artificial left and right ventricles are attached by a surgeon.
The patient has a large surface exposed to the flow of blood as the blood
comes in contact with the artificial ventricles, the connection tubes and the
valves. Blood clotting, hemolysis and degradation of blood become
problems in this situation.
For an entire generation, attempts have been made to create a
heart assist device which leaves the native heart in place and squeezes the
native heart. The blood is thus exposed only to the patient's natural tissue.
Clotting on natural tissue is extremely rare. Pneumatically and electrically
driven devices have been evaluated, but these devices have not reached
clinical application. These devices have wrapped around the entire heart
and squeezed both the left and right ventricles. Unfortunately, this does
not mimic the way the heart contracts.
U.S. Patent No. 4,925,443 illustrates a heart assist device
including a tension band which is surgically placed within an interventricular
muscle wall in order to compensate for weakness of the interventricular
muscle wall or septum. An operating mechanism then opens and closes a
pair of pressure plates to compress the left ventricle. The drawback to this
device, however, is that the interventricular wall or septum experiences
significant trauma due to the surgical implantation of the band within the
wall or septum itself. Especially in cases in which the interventricular wall
is already weakened, such trauma could severely damage the heart.
Another proposed device is disclosed in U.S. Patent No.
5,1 19,804. With this device, the heart is placed within a cup having a
vacuum source connected to hold the cup in position around the heart and
having a pulsed pressure system to alternately apply relatively high positive
and negative pressures to provide systolic and diastolic effects on the heart.
This system, however, squeezes the entire heart muscle at one time and
will tend to cause weaker portions of the heart to bulge outward while
stronger portions of the heart muscle retain a normal shape. Therefore, the
contraction applied to the heart muscle is not a natural one, but one that is
dictated by the particular heart problems of the patient.
Another ventricular assist device is disclosed in U.S. Patent
No. 4,685,446. This device utilizes an inflatable balloon secured to the end
of a catheter and inserted into the left ventricle. The balloon is inflated
during left ventricular systole and then deflated in a repeating manner.
Unfortunately, this device will also tend to cause weakened portions of the
heart muscle to bulge around the left ventricle rather than causing the
intended function of expelling blood from the ventricle. Thus, the ejection
fraction of blood can be deficient with this device as well.
Despite the intuitively attractive nature of heart assist devices,
no device has ever been clinically proven. Attention to some physiologic
details will make the difference. The left ventricle is a thick-walled
structure which propels blood into the systemic circulation at high pressure.
The left ventricle is shaped as a truncated cone. During systole
(contraction) this cone shortens along its length and narrows around its
circumference. By this narrowing and shortening action, the internal
volume of the left ventricular cavity decreases and blood is expelled. In a
healthy heart, 60% to 70% of the blood volume (that is, the ejection
fraction) is expelled on each beat. As the heart fails, the cavity enlarges,
the heart wall thins and progressively smaller fractions of blood are expelled
on each beat. In other words, the heart shortens and narrows much less
during each beat.
The right ventricle has been described as a bellows pump. It
wraps around and attaches to the circumference of the outside of the left
ventricular wall. The outside wall of the right ventricle is considerably
thinner than the wall of the left ventricle and also contracts against a lower
pressure. The energy consumption of the right ventricle is therefore much
lower than that of the left ventricle. The right ventricle expels blood when
the muscle shortens and reduces the diameter of the crescent shaped cavity
which is located between the outside wall the interventricular wall or
septum shared with the left ventricle.
It is not surprising that merely squeezing the left and right
ventricles with a device wrapped around both ventricles has not been
successful. With previous devices, the left ventricle does not shorten from
base to apex. There is also limited short axis shortening because the device
does not squeeze the left ventricle in isolation, but with the right ventricle.
To be effective the left ventricle requires more controlled compression.
Generally, blood must be expelled from the ventricle in a more controlled
and complete manner.
Summary of the Invention
The present invention is generally directed toward heart
support and assist devices including fully passive restraints, combinations
of passive and active devices and fully active devices for assisting with
heart contractions. Passive restraints generally include an external support
member, which may be a strap, web or mesh, sheathing or other member
configured to extend around the outside of the heart coupled with an
internal support member extending within at least one of the ventricles and
against one side of the interventricular septum. This type of passive
restraining system can assist the heart muscle by supporting those portions
of the muscle necessary to produce efficient contractions either naturally or
with another active assist device. This support is provided in a manner that
minimizes trauma to the heart muscle. Additional internal tensile members,
such as cables, may be connected to the external tensile member or
members longitudinally and/or transversely through one or both ventricles.
These cables will assist with long axis and short axis shortening of the
heart muscle during each contraction.
Combinations of passive and active devices may include, for
example, external support members, in the form of straps, sheaths, wraps,
mesh elements or webs, etc., combined with a blood pump connected for
fluid communication directly with the left ventricle, right ventricle or both.
Alternatively, a fluid inflatable bladder may be placed between the external
tensile member and the outside surface of the heart to provide compression
to one or both of the ventricles to assist in pumping blood through the
heart. Finally, an active contraction device may integrate an external tensile
member system with a powered actuator device to provide cyclical
compression of the heart muscle through a pulling action on the tensile
member or members.
ln another aspect, the invention is directed to a heart assist
device generally including a plurality of flexible tensile members adapted to
be wrapped circumferentially about the heart of a patient. At least one
tensile member is configured to extend around the left ventricle and a
second tensile member is configured to extend around the right ventricle. A
support member is configured to be received within the right ventricle
against the interventricular septum and coupled to at least one of the first
and second tensile members. This support member may be a portion of at
least one of the tensile members or may be a separate member connected
to at least one of the tensile members. At least one powered actuator may
be operatively connected with the first and second tensile members and
operates to pull the tensile members respectively against the left and right
ventricles to expel blood therefrom.
More preferably, the heart assist device includes a plurality of
tensile members configured to extend around the left ventricle and a
plurality of tensile members configured to extend around the right ventricle.
Each tensile member is secured at least indirectly to the support member.
The support member is preferably a plate covered with a biocompatible
material for inhibiting blood clotting. The actuator pulls the tensile members
extending around the left ventricle against the outside surfaces of the heart
and pulls the support member or plate against the interventricular septum in
an opposing direction. The tensile members extending around the right
ventricle are pulled against the left ventricle in an independent fashion.
One preferred embodiment of the invention may include a
plurality of pulley members coupled with the tensile members and operating
to allow a single powered actuator, such as an electric or pneumatic
actuator, to pull multiple tensile members. Alternatively, multiple powered
actuators may be used to independently pull the various tensile members.
The tensile members, pulleys and other actuating structure may be
contained in a suitable jacket or sheath positioned around the heart.
In accordance with another aspect of the invention, at least
one internal tensile member is provided and configured to be connected
lengthwise within the left ventricle between the mitral valve of the heart
and the apex of the left ventricle. The internal tensile member inhibits
lengthening of the ventricle when the powered actuator or actuators pull
the tensile members to compress the left and right ventricles. As further
options, transverse, internal tensile members may be connected within the
left ventricle between the outside wall thereof and the interventricular
septum to control widthwise expansion. Also, one or more internal tensile
members may be utilized in the right ventricle for similar purposes.
As additional aspects of the invention, the tensile members
may be contained in sleeves to prevent cutting of the heart by the tensile
members during use. Also, a plurality of coronary obstruction preventing
members may be used between the tensile members and the coronary
arteries on the outside of the heart for preventing the coronary arteries from
being compressed and obstructed by the tensile members.
The present invention also generally contemplates methods for
assisting the pumping action of the heart. In a preferred embodiment, the
method includes inserting an anchor member within the right ventricle and
against the interventricular septum; encircling the outside of the right and
left ventricles with respective tensile members; coupling the tensile
members with the anchor member; and compressing the right and left
ventricles by pulling the tensile members against the outside of the heart.
Other methods will be apparent to those of ordinary skill based on a full
review of this disclosure.
In various aspects of the invention, a basic device for assisting
a heart may comprise a plurality of flexible, external tensile members
adapted to be wrapped circumferentially around the heart of a patient.
Preferably, this includes at least a first external tensile member configured
to extend around the left ventricle and a second external tensile member
configured to extend around the right ventricle. In accordance with the
invention, an internal support member is configured to be received within at
least one of the left and right ventricles and against the interventricular
septum. This support member is coupled either directly or indirectly to at
least one of the first and second external tensile members. The internal
support member may comprise a portion of one or more of the external
tensile members or may be a separate member, such as a plate, coupled
with the external tensile members. The external tensile members are
preferably flat straps or other similar structures that will not harm the
outside of the patient's heart, and may be formed from any biocompatible
material. In various embodiments, the support members may be implanted
either partially or completely through one or more catheters.
In another embodiment of the invention, at least one of the
first and second external tensile members may be configured generally in a
spiral shape to facilitate the application of compression to the heart. In this
embodiment, for example, one or more coils of the spiral may extend into
one of the ventricles of the heart and bear against one side of the
interventricular septum to form a support member as described above. An
actuator is used to draw the spiral-shaped external tensile member into a
tighter, coiled shape to actively compress or passively support one or both
ventricles of the heart.
In another embodiment of the invention, the first and second
external tensile members are configured as first and second halves of a cup.
The cup is configured to envelop the patient's heart and comprises first and
second shells with at least a first bladder configured for disposition between
one of the shells and an outside surface of the heart. As with the other
embodiments, one or more support members extend between opposite
sides of the cup and within one or both ventricles of the heart to bear
against the interventricular septum. A pump is provided for selectively
inflating and deflating the bladder to apply compression to at least one of
the left and right ventricles. In the preferred embodiment, a bladder is
connected within each of the shells associated with the cup for
compressing both of the ventricles. The support member or members are
connected at a position generally between the first and second halves of
the cup such as by being retained in place by the same connectors used to
affix each half of the cup together. The cup may be formed in one, two or
more pieces and, again, is formed from any suitable biocompatible material
or materials as with all of the implantable components of each embodiment.
Various objectives, features and advantages of the invention
will become more readily apparent to those of ordinary skill in the art upon
review of the following detailed description taken in conjunction with the
the accompanying drawings.
Brief Description of the Drawings
Figure 1 is a perspective view showing one embodiment of the
invention in an illustrative manner coupled to a patient's heart;
Figure 2 is a partially fragmented perspective view showing
the heart assist device of Figure 1 coupled to the patient's heart;
Figure 3 is a cross sectional view taken generally along line
3-3 of Figure 2;
Figure 3A is a cross sectional view similar to Fig. 3, but
illustrating optional inflatable bladders for providing a pump assist to the
heart;
Figure 4 is perspective view illustrating an embodiment with a
single powered actuator for operating the heart assist device through the
use of pulleys;
Figure 5 is a perspective view similar to Figure 4, but showing
independent powered actuators;
Figure 6 is a perspective view of another alternative assist
device comprising a spiral-shaped external tensile member;
Figure 7 is an exploded perspective view illustrating another
alternative heart assist device comprised of a split cup and inflatable
bladder system;
Figure 8 is a perspective view of another alternative heart
assist device used to directly pump blood into one or more heart chambers;
Figure 9 is a fragmented perspective view of the heart with
another embodiment of a passive heart support device implanted around
the left ventricle;
Figure 10 is a perspective view of a passive heart support
device similar to Figure 9 but having alternative internal support members;
Figure 1 1 is a transverse, cross sectional view of a heart with
another alternative passive support device;
Figure 12 is a cross sectional view showing an initial step of
implanting a catheter-implanted heart support device;
Figure 12A is a fragmented perspective view showing one
embodiment of a catheter-implanted heart support device;
Figure 13A is a schematic, cross sectional view of the heart
during a later step of implanting the catheter-implanted support device;
Figure 13B is a cross sectional view similar to Figure 13A, but
illustrating the fully implanted, catheter-implanted passive support device;
Figure 14A is a transverse, cross sectional view of a heart
schematically illustrating another catheter-based implantation method of a
passive support device;
Figure 14B is a cross sectional view similar to Figure 14A, but
illustrating a later point in the implantation procedure;
Figure 14C is a cross sectional view similar to Figures 14A
and 1 4B, but illustrating the fully implanted support device;
Figure 1 5 is a partially sectioned, perspective view of a heart
with another alternative passive support device affixed around the left
ventricle;
Figure 1 6 is a schematic, perspective view showing the heart
in cross section and another alternative passive support device; and
Figure 1 7 is a schematic, cross sectional view of the heart
shown in Figure 1 6 with the device fully implanted around the left ventricle.
Detailed Description of the Preferred Embodiments
Figure 1 illustrates a heart assist device 10 constructed in
accordance with the invention and schematically illustrated implanted
within a patient 1 2 in surrounding relation to the patient's heart 1 4. A
power supply 1 6, such as an electric or pneumatic power supply, is
operatively connected to heart assist device 10 for reasons to be discussed
below. As generally shown in Figure 2, heart 14 has four chambers. The
right atrium 1 8 receives blood flowing through veins in the patient's body.
The right ventricle 20 pumps the blood to the lungs of the patient through
the pulmonary artery 22. The left atrium 24 receives oxygenated blood
flowing back from the patient's lungs through the pulmonary vein and the
left ventricle 28 pumps this blood out through the aorta 30 to the patient's
body. The right and left ventricles 20, 28 compress simultaneously during
this pumping action and, in a normal heart, anywhere between about 50%
and 80% of the blood in these chambers will be expelled as described
above. In a heart weakened, for example, due to heart attack or other
conditions, the efficiency of the heart will be reduced and, therefore, heart
assist device 10 will be used to increase the pumping action or expulsion of
blood from the right and left ventricles 20, 28. An interventricular septum
32 separates the right and left ventricles 20, 28.
As further shown in Figures 2 and 3, device 1 0 preferably
comprises a plurality of flexible tensile members 40a through 40f. In this
embodiment, a flexible tensile member 40a is adapted to be wrapped
circumferentially around left ventricle 28, as is another flexible tensile
member 40b. A tensile member 40c may interconnect tensile members
40a and 40b as shown. A similar system is shown with tensile members
40d, 40e and 40f extending along the outside of right ventricle 20. Each
of these tensile members is effectively connected to the other to form an
integrated unit by connection to an internal support anchor member 42. In
this embodiment, support member 42 comprises a plate surgically inserted
into right ventricle 20 and bearing against interventricular septum 32. Plate
42 may comprise a plate of rigid or semi-rigid polymeric material or metallic
material covered in a biocompatible material adapted to resist blood
clotting. Once plate 42 is implanted through a suitable incision into right
ventricle 20, flexible tensile members 40a, 40b, 40d and 40e may be
sutured thereto as shown in Figure 2. Alternatively, one of the pairs of
tensile members may be secured to plate 42, while the other pair is secured
to the first pair.
As shown in Figure 2, tensile members 40a through 40f may
comprise flexible cables contained within a sheath or sleeve of
biocompatible material. Internal flexible tensile members 44, 46, 48, 50
may be used to control the movements of the heart muscle as device 10 is
used to assist with the pumping action as described further below. Two
tensile members 44, 46 may be secured between the annulus 52 of mitral
valve 54 and the apex 56 of left ventricle 28. A button 58 may be used at
the apex for securement purposes and may bear against the intersections of
tensile members 40c, 40f. Transverse internal tensile members 48, 50
may extend crosswise as best shown in Figure 3 between the outer wall of
left ventricle 28 and the interventricular septum 32. Tensile members 48,
50 may be secured to any of the outer tensile members, as well as to plate
42 at opposite ends, or may be secured to the walls of the heart itself.
Similar internal tensile members may be used in the right ventricle, although
this is not preferred for the reason that it may not be necessary as the
motion of the right ventricle is primarily in a direction toward the
interventricular septum. Also, it will be understood that tensile members
44, 46 may be secured in other ways within left ventricle 28, such as by
being secured to an annuloplasty ring or to a replacement mitral valve.
Figure 3A illustrates an alternative passive/active heart assist
device 1 0' taking the form of a modified version of device 1 0 shown in
Figures 2 and 3. Device 1 0' includes various elements having like
reference numerals in Figure 3, but adds an inflatable bladder 47 which
may be positioned between flexible tensile member 40a and the outside
wall of left ventricle 28. Bladder 47 is connected through a suitable
conduit 49 to a fluid pump which may direct air or other fluid into bladder
47 in a cyclical manner. Inflation and subsequent deflation of bladder 47
will contract left ventricle 28 against the support provided by internal
support member 42 to expel blood and subsequent deflation will allow left
ventricle 28 to expand and refill with blood. Alternatively, an internal
bladder 53 may be provided and cyclically inflated and deflated, as shown,
to expel blood from left ventricle 28 and allow subsequent refilling of the
ventricle with blood. Bladder 53 would likewise be supplied with air or
other appropriate fluid through a catheter from a suitable pump device (not
shown).
As further shown in Figure 4, a series of pulley members 60
may be used with a single actuator 62, such as an electric solenoid or
pneumatic actuator having a reciprocating element 62a attached to a series
of cables or tensile members 63 extending through pulley members 60.
Actuator 62 may be contained in a suitable pouch 64 or other containment
structure and springs 66, 68 may be used to control the amount of
compression applied by cables or tensile members 63. As reciprocating
member 62 moves inwardly in the direction of the arrow in Figure 4, cables
or tensile members 63 will move under tension and cause simultaneous
compression of the right and left ventricles.
Figure 5 illustrates an embodiment similar to Figure 4, but
using multiple actuators 70, 72, 74 for independently applying compression
to heart 14. Actuator 70 applies transverse compression to an upper
portion of heart 14, while actuator 72 applies transverse compression to a
lower portion of heart 14. Actuator 74 applies compression in a lengthwise
direction. As with the other embodiments, suitable flexible tensile
members, such as cables extending over or within straps, are provided to
apply the compression upon operation of actuators 70, 72, 74.
Figure 6 illustrates another alternative heart support and assist
device 80 formed by a generally spiral shaped tensile member 82 extending
around heart 14. Tensile member 82 preferably comprises an outer hollow
member 84 and an inner movable cable 86 connected at one end to a
suitable actuator 88 affixed to a jacket 90 and at an opposite end being
rigidly affixed by a connector 92 to jacket 90. An upper end of jacket 90
may be suitably connected to heart 14, as through stitching 94. As shown
in Figure 6, two coils of the spiral tensile member 82 extend into right
ventricle 20 and bear against interventricular septum 32 before exiting
heart 14 and again extending around the outside of jacket 90. The
remaining upper and lower sets of coils extend around the outside of jacket
90. This configuration is intended to compress both the right and left
ventricles 20, 28 of heart 14, while focusing on left ventricle 28, which is
the ventricle with which most heart patients experience problems.
Actuator 88 may be a conventional linear electric actuator that cyclically
pulls on cable 86 in concert with the patient's own natural heart rhythm or
as activated by a conventional pacing device which sets the patient's heart
rhythm. It will also be appreciated that this type of generally spiral-shaped
support device may be used in a passive manner without an active pump
assist function. The spiral shape can be used for adjusting the tightness of
tensile member 82 against the heart for achieving the proper amount of
support.
Figure 7 illustrates another alternative heart assist device 100
comprised of a cup having two halves 102, 104 which together receive a
patient's heart 14. Each half 102, 104 is respectively comprised of an
outer shell and innerinflatable bladder combination 106, 108 and 1 10, 1 12.
One or more internal support members 1 14, 1 16 extend generally between
halves 102, 104 through heart 14. Support members 1 14, 1 16 are
intended to extend through one or both of the left and right ventricles (not
shown) of heart 14 and bear against the interventricular septum (not
shown), as with the support members used in other embodiments of the
invention. This provides support for the interventricular septum during
compression of the heart without a significant amount of trauma to the
heart muscle. Support members 1 14, 1 1 6 may, for example, be one or
more rigid plates or flexible straps, or other suitable support members.
Respective connectors 1 18, 120 may be provided to affix halves 102, 104
together. In this illustrative example, connectors 1 18 extend through holes
1 14a, 1 16a in support members 1 14, 1 16 and into connectors 1 20 of half
104 to connect device 100 firmly against heart 14. Additional connectors
or other means may be used to ensure that device 100 remains in position
around heart 14. Once in position, bladders 108, 1 12 may be cyclically
inflated and deflated to compress the left and right ventricles of heart 14
while the opposite side of one or each of the ventricles is supported by
members 1 14, 1 16. A pump 124 may be connected to bladders 108, 1 12
for selectively inflating and deflating bladders 108, 1 12 with an appropriate
fluid, such as air or liquid. Again, pump 124 may be activated in
correspondence with the patient's heart rhythm, such as through the use of
a conventional electrical pacing device.
Figure 8 illustrates another alternative heart assist device 130
comprised of a flexible strap system 132 configured for disposition around
a patient's heart 14 and connected with a suitable internal support member
134 for bearing against one side of the interventricular septum within one
of the heart's ventricles, as previously discussed. In this embodiment, at
least one pump 136 is directly connected through a suitable conduit, such
as a catheter 138, to one of the ventricles of heart 14. For example, pump
136 may be connected to the left ventricle of heart 14 for directly pumping
blood into the left ventricle to assist with the movement of blood through
heart 14. Likewise, another pump 140 may be directly connected to the
right ventricle of heart 14 through another conduit 142 for assisting with
blood flow through the right ventricle. Pumps 136 and 140 may obtain
blood from any suitable vessel within the patient's body.
Figure 9 illustrates a passive heart support device 1 50 shown
implanted on a heart 14 and, specifically, around left ventricle 28. Support
device 1 50 includes a flexible mesh or web material 1 52 serving as an
external support member around left ventricle 28 and a plurality of internal
support members 1 54, 1 56, 1 58 extending through right ventricle 20 and
against interventricular septum 32. Internal support members 1 54, 1 56,
1 58 may be attached to mesh or web element 1 52 in numerous ways,
such as by stitching or other quicker connection means. At least one end
of internal support members 1 54, 1 56, 1 58 will be detached from mesh or
web element 1 52 for extension through right ventricle 20 during
implantation and then adjusted for tightness on heart 14 and secured to
mesh or web element 1 52 preferably at an opposite side of the heart. If
necessary, an external sheath 1 60, which may be elastic in nature, may
receive heart 1 4 after attaching device 1 50, as a further securement
means. Sheath 1 60 may include an open end 1 62 and a closed end 1 64.
Figure 10 illustrates an alternative device 1 50', which is
similar to device 1 50, and includes a mesh or web element 1 52 for
supporting an external portion of the heart. A plurality of internal support
members 1 62a, 1 62b and 1 64a, 1 64b are connected to opposite sides of
mesh element 1 52. Device 1 50', for example, may be introduced into a
patient's chest through a relatively small port hole and, using catheter-
based devices, internal support elements 1 62a, 1 62b and 1 64a, 1 64b may
be secured across the interventricular septum as generally shown in Figure
9.
Figure 1 1 illustrates another alternative passive support device
1 70 comprising an external support portion 1 72, which may again be
another flexible mesh or web element 1 72 and internal support member
1 74, 1 76. In this embodiment, support member 1 76 extends only partially
along the interventricular septum 32 and internal support member 1 74
extends through septum 32 and connects with external support member
1 72 at one end and internal support member 1 76 at an opposite end.
Support members 1 74 and 1 76 may be separate members which are
connected together or may be a single integral member, as shown.
Additional support members 1 78, 1 80, shown in phantom, may be
optionally used in addition to or as an alternative to internal support
member 1 74.
Figures 1 2, 1 2A and 1 3A-B illustrate a partially catheter-based
implantation device and method. Specifically, a catheter 1 90 having a
sharpened portion 1 92 is introduced from a vein 1 94, for example,
originating in the groin of the patient. Catheter 1 90 enters right atrium 1 8
and pierces through wall 1 8a into right ventricle 20. A heart support
device 200 may comprise a cable which, for example, may include a sheath
(not shown) and which acts as both an external and internal support
members for heart 1 4. Catheter 1 90 may be used to introduce opposite
ends of support device 200 through opposite walls of right ventricle 20, as
shown in Figure 1 3A. Piercing member 1 92 may, for example, extend to
fully pierce through the wall of the heart, or device 200 itself may pierce
through the wall of heart 14. Device 200 includes two looped ends 202,
204 with at least one of these ends being collapsible in the form of a
tightening noose. In the embodiment shown, this is end 204. A tool 210
may be introduced through a small port hole in the patient's chest and
includes a hook member 212. Tool 210 extends through loop 204 and
hook 212 may be used to grasp looped end 202 to pull it through looped
end 204. Looped end 204 is then tightened as shown in Figure 13B so
that an internal portion 200a of device 200 lies against septum 32 within
right ventricle 20 and another portion 200b of device 200 lies on the
external surface of heart 14 adjacent left ventricle 28.
Figures 14A and 14B illustrate another alternative embodiment
of the invention in the form of a completely catheter-based fixation method
using first and second flexible gripper members 220, 222 which may be
introduced through the same catheter (not shown) or separate catheters
(not shown). Gripper members 220, 222 include jaws 220a, 222a which
may be actuated to grip the ends of a support member 230. Support
member 230 includes respective ends 230a, 230b retained between jaws
220a and 222a. As with the previous embodiment, gripper members 220,
222 may be introduced into right ventricle 20, pierced through the heart
wall 14a adjacent septum 32 and directed around the outside of left
ventricle 28. Support member 230 includes ratchet-type connector ends
230a, 230b which may be connected together as shown in Figure 14B
with end 230b being inserted into end 230a and retained by the teeth on
end 230b. Jaws 220a, 222a release ends 230a, 230b and then are used
to grip the opposite end 230a, 230b after engagement to allow pulling of
the ends 230a, 230b in opposite directions for tightening and locking
device 230 around left ventricle 28. It will be appreciated that other forms
of the device, as well as other forms of the connecting and locking
elements may be used as well. Also, other portions of the heart may be
supported and this type of catheter-based insertion method and device may
be used in conjunction with other supporting and/or assisting devices.
Figure 1 5 illustrates another alternative heart support device
240 comprised of three flexible support members 242, 244, 246 extending
around the outside of left ventricle 28. Portions 242a, 244a and 246a
extend through the wall of the heart into right ventricle 20 and connect
with a support plate 248 lying against septum 32.
Figures 1 6 and 1 7 illustrate another alternative passive heart
support device 250 comprising a substantially rigid annular member having
two ends (not shown) affixed to one another by a connector 252. Two
inwardly projecting portions 254, 256 exert pressure selectively to small
areas of the heart muscle. Specifically, for example, portions 254, 256
may be positioned to exert selective support to the papillary muscle regions
of the heart, or to other weakened areas of the heart depending on the
particular needs of the patient. Support member 250 is rigid enough to
provide such support in a manner that prevents undesirable, outward
bulging of the heart muscle. As apparent from Fig. 1 6, device 250 may
also be configured to extend only around the outside surface of the heart.
While the present invention has been illustrated by a
description of preferred embodiments and while these embodiments have
been described in some detail, it is not the intention of the Applicants to
restrict or in any way limit the scope of the appended claims to such detail.
Additional advantages and modifications will readily appear to those skilled
in the art. The various features and concepts of the invention may be used
alone or in numerous combinations within each embodiment or between the
embodiments depending on the needs and preferences of the user. This
has been a description of the present invention, along with the preferred
methods of practicing the present invention as currently known. However,
the invention itself should only be defined by the appended claims, wherein
we claim: