Intrapericardial assist method

A surgical method for assisting cardiac function utilizes a balloon initially in a collapsed configuration. The balloon is inserted onto an intrapericardial space about a patient's heart and is disposed about one portion of the patient's heart. The method further includes inflating the balloon in the intrapericardial space to compress one portion of the patient's heart. A lower end portion of the patient's heart is separately compressed by an additional instrumentality to reduce ventricular volume.

FIELD OF THE INVENTION
 This invention relates to a method for improving cardiac function. More
 particularly, this invention relates to an intrapericardial assist
 procedure. The invention is useful in assisting a patient's heart in its
 pumping function, even where there is congestive heart failure. This
 invention also relates to a method for assisting a patient's heart in its
 pumping function.
 BACKGROUND OF THE INVENTION
 When a patient's heart stops, for example, in the operating room,
 cardiopulmonary resuscitation (CPR) is required. In that procedure the
 chest is violently pounded at the region of the sternum to compress the
 chest and thereby compress the heart between the sternum and the spine.
 This compression forces blood out of the ventricles through the one-way
 valves of the heart. When the pressure on the heart is released, the heart
 expands and blood is sucked into the heart.
 For all its violence, CPR is a delicate procedure in that it must be
 performed correctly in order to have the desired result of starting the
 stopped heart. A problem with CPR is that, whether or not it is performed
 correctly, CPR invariably results in cracked ribs, a fractured sternum and
 destroyed costo-chondral (cartilage) junctions. Thus even if a patient
 survives CPR, he is usually injured.
 Another serious cardiac condition arises in people who have experienced
 heart attacks. In such persons, a portion of the heart muscle is
 frequently destroyed by the attack. Although nerves passing through the
 damaged heart tissue are not destroyed to the point of ceasing function,
 the operation of the nerves may be significantly impaired. Conduction of
 nerve impulses may be delayed. This delay in signal transmission over the
 impaired nerves results in a delay in heart muscle contraction in those
 parts of the heart controlled by the impaired nerves. This condition is
 observed as a "bundle branch block" in an electrocariogram.
 Reviving a patent after cardiac arrest is made more difficult when the
 patient suffers from congestive heart failure. Congestive heart failure
 occurs, inter alia, where there has been a heart attack or an infection.
 In either case, the pumping action of the heart is impaired. In another
 malfunction, left ventricular hypertrophy, the myocardium of the left
 ventricle becomes thickened to the point of interfering with effective
 heart contraction. Hypertrophy of the left ventricular muscle arises from
 a sticky heart valve or aortic stenosis. The increase in left ventricular
 pressure resulting from increased resistance to blood flow out of the left
 ventricle gradually induces an increase in the size of the myocardium
 about the left ventricle. This left ventricular hypertrophy is a dangerous
 condition, particularly where the individual suffers from coronary artery
 disease. The larger heart muscle requires greater blood flow and is
 therefore more sensitive to even temporary reductions in that flow. Such a
 reduction in blood flow occurs, for example, when the afflicted individual
 exercises.
 A surgical procedure for treating congestive heart failure, developed by a
 doctor in Brazil, involves removing a triangular portion of a patient's
 heart. In this operation, approximately one-third of the patient's left
 ventricular muscle is removed. The result is that the smaller heart pumps
 more efficiently. This technique of course requires open heart surgery,
 with its attendant expense and extended convalescence.
 OBJECTS OF THE INVENTION
 An object of the present invention is to provide a method and/or an
 associated device for assisting cardiac function.
 A more particular object of the present invention is to provide such a
 method and/or device which is less traumatic than conventional manual
 heart resusitation techniques.
 Another particular object of the present invention is to provide such a
 method and/or device wherein the device is implanted into the
 intrapericardial space.
 A further object of the present invention is to provide such a method
 and/or device which can compensate for or take into account congestive
 heart failure.
 Another object of the present invention is to provide such a method and/or
 device which is of simple construction.
 A further, more particular, object of the present invention is to provide
 such a method and/or device which is implemented at least partially
 automatically.
 These and other objects of the present invention will be apparent from the
 drawings and detailed descriptions herein.
 SUMMARY OF THE INVENTION
 The present invention is directed to a surgical method for assisting
 cardiac function and utilizes a balloon which is initially in a collapsed
 configuration. Pursuant to the present invention, the balloon together
 with another preferably implantable device is inserted into a patient
 inside the pericardium. More particularly, the balloon is positioned in
 the intrapericardial space. The secondary device is employed to close off
 the lower end portions of the patient's ventricles, the balloon being used
 to contract or compress the remaining portion of the patient's heart to
 squeeze blood from the reduced-size ventricles.
 The secondary device may operate in compression to contract the lower
 portion of the patient's heart. In that case, the secondary device is also
 inserted at least partially into the pericardium and positioned about the
 lower portion of the patient's heart. Specific forms of the secondary
 device are an anciliary balloon and a pronged or fingered element.
 Alternatively, the secondary device may operate by tension. In that case,
 the secondary device may be deployed intravenously. A catheter is inserted
 into a ventricle and a wire ejected from the catheter. The wire is pushed
 into the myocardium and tension is placed on the wire to pull generally
 opposing walls of the heart together, thereby reducing the volume of the
 ventricles at their lower ends.
 Where two balloons are used to carry out the cardiac assist method of the
 present invention, one of the balloons is disposed about one portion of
 the patient's heart and the other of the balloons about another portion of
 the patient's heart. The method further includes differentially inflating
 the balloons in the intrapericardial space to differentially compress the
 different portions of the patient's heart. More specifically, one balloon
 is placed about a lower part of the patient's heart and is inflated and
 maintained in an inflated configuration, while the other balloon is placed
 about a higher portion of the patient's heart and periodically or
 repeatedly inflated and alternately deflated to push blood from the
 patient's ventricles in pulsatile fashion.
 The insertion of the balloons may be implemented in a minimally invasive
 manner by using a hypodermic type needle. The needle is inserted through a
 skin surface and into the intrapericardial space, and the balloons are
 injected in collapsed configurations into the intrapericardial space. It
 is to be noted, however, that the present method may be utilized in open
 surgical procedures as well as in minimally invasive procedures.
 Where an intrapericardial assist device in accordance with the present
 invention comprises a pair of balloons connected to one another, the
 balloons have predetermined sizes and shapes in an expanded configuration
 so that the balloons are capable of being disposed in a patient's
 intrapericardial space about the patient's heart. The device further
 comprises a first pressure source operatively connected to one of the
 balloons for controllably pressurizing the one of the balloons and a
 second pressure source operatively connected to the other of the balloons
 for controllably pressurizing the other of the balloons. Preferably, the
 balloon which is repeatedly inflated and alternately deflated has a
 configuration of a cuff in an expanded configuration. The balloon which is
 positioned about the lower end of the patient's heart may have a
 substantially cup-shaped configuration conforming to the lower end of the
 patient's heart. One or more spring elements exemplarily in the form of
 ribs may be connected to the balloons for automatically unfurling the
 balloons from a folded collapsed configuration to an unfolded collapsed
 configuration.
 A method and device in accordance with the present invention is capable of
 compensating for differential action of an individual's heart. The method
 and device are effective when a chamber of the individual's heart
 experiences excessive pressure levels owing, for example, to a sticky
 valve or aortic stenosis.

DESCRIPTION OF THE PREFERRED EMBODIMENTS
 As illustrated in FIG. 1, an intrapericardial assist or resuscitation
 assembly comprises an alternately inflatable and collapsible balloon 12 in
 the form of a cuff. Cuff 12 has an elongate tube 14 extending to a valve
 device 16 which is connected to a suction source or vacuum generator 18
 and to a source 20 of pressurized fluid such as water, saline solution or
 a gas such as air. In response to signals from a control unit 22, valve
 device 16 periodically connects cuff 12 to pressure source 20 and
 alternately to suction source 18, whereby cuff 12 is rapidly and
 forcefully inflated with a predetermined periodicity.
 Control unit 22 may be provided with setting knobs (not illustrated) for
 varying the rate and maximum pressure that is applied to the cuff upon
 proper disposition thereof in the intrapericardial space about the heart.
 As illustrated in FIGS. 1 and 2, cuff 12 has an arcuate, generally C-shaped
 configuration in its expanded or inflated state. Cuff 12 has a pair of
 major C-shaped walls 24 and 26 defining a pressurization chamber 28.
 Embedded in walls 24 and 26 are spring elements or ribs 30 and 32 which
 can be bent into a curled configuration (see FIG. 3) but which tend to
 resume their C-shaped expanded configurations when cuff 12 is placed into
 an intrapericardial space during a cardiopulmonary resuscitation
 procedure.
 As illustrated in FIGS. 3 and 4, prior to a cardiopulmonary resuscitation
 procedure, cuff 12 is folded and inserted in a collapsed configuration
 inside a hollow hypodermic type needle 34. Needle 34 is provided at a
 distal end 36 with an aperture 38 for the ejection of folded and collapsed
 cuff 12 by a distally directed stroke of a plunger member 40 upon a
 disposition of distal end 36 into an intrapericardial space during a
 cardiopulmonary resuscitation procedure. Distal end 36 is also provided
 with an electrical sensor for detecting the surface of the heart, as is
 conventional in known intrapericardial sampling needles.
 Distal end 36 of intrapericardial needle 34 is inserted into the
 intrapericardial space through the skin under the patient sternum.
 FIG. 5 shows the placement of cuff 12 in an intrapericardial space between
 a heart HT and the associated surrounding parietal pericardium PP. The
 diagram also shows the superior vena cava SVC, the pulmonary artery PA,
 the ascending aorta AA, and other veins and arteries.
 As depicted in FIG. 6, an inflatable intrapericardial cuff 42 may be
 provided with a plurality of longitudinally extending ribs 44 and a
 plurality of transversely extending expansion ribs 46. Each rib 46 has a
 memory whereby the rib may be bent for insertion and retrieval from a
 patient's intrapericardial space, but tends to assume a pre-established
 configuration (FIG. 6) upon insertion of the cuff 42 into an
 intrapericardial space or cavity.
 In another cuff insertion procedure depicted in FIGS. 7A-7C, a sharp distal
 tip 48 of an intrapericardial needle 50 is inserted through a patient's
 skin SS under the sternum ST. A dilating device 52 comprising a plurality
 of longitudinal ribs 54 interconnected by stretchable membranes 56
 surrounds needle 50 during the insertion procedure. Upon the insertion of
 distal tip 48 into the intrapericardial cavity at the patient's heart,
 dilating device is slid in the distal direction so that a distal end
 portion thereof is disposed or inserted into the intrapericardial cavity.
 Needle 50 is then removed, as shown in FIG. 7B.
 Upon the removal of needle 50 from the patient, leaving dilating device 52
 partially inserted into the patient's intrapericardial cavity, the
 dilating device may be expanded, for example, by the insertion of a series
 of increasing large elongate rigid dilators (not shown). Then, cuff 12 or
 42 is inserted in a folded collapsed collapsed configuration into the
 intrapericardial cavity through the expanded dilating device 52, as shown
 in FIG. 7C. An inserter (not illustrated) may be used for pushing the cuff
 through dilating device 52.
 The general use and structure of dilating device 52 is described in detail
 in allowed U.S. patent application Ser. No. 851,097 filed Mar. 13, 1992
 and U.S. patent application Ser. No. 893,991 filed Jun. 5, 1992. The
 disclosures of those applications are hereby incorporated by reference.
 As depicted in FIG. 8, an intrapericardial assist device comprises an
 electrode carrier in the form of an inflatable balloon 60 adapted for
 juxtaposition to a patient's heart in an intrapericardial space, as
 discussed hereinabove with reference to FIG. 5. The electrode-carrying
 balloon 60 has an inwardly facing surface 62 adapted for contact with the
 patient's heart. An array of electrical contacts or electrode wires 64 is
 disposed on contact surface 62 of balloon 60 for conducting electrical
 energy to the patient's heart upon an insertion of balloon 60 into the
 intrapericardial space. Current transmission elements or leads 66 are
 operatively connected to electrical contacts 64 for delivering electrical
 energy thereto from a voltage source 68. A hose 70 extends to balloon 60
 for maintaining the balloon in an inflated state and thereby maintaining
 the balloon's contact surface 62 in adequate engagement with the patient's
 heart during the application of electrical energy to the heart via voltage
 source 68, transmission leads 66 and electrical contacts or electrodes 64.
 Balloon 60 is a collapsible member with a configuration of a slotted cuff
 in an expanded configuration. Balloon 60 has a predetermined size and
 shape in the expanded configuration so that it is disposable in the
 intrapericardial space in juxtaposition to the patient's heart.
 Preferably, one or more spring elements in the form of elongate ribs, e.g.
 30, 32 (FIG. 2) or 44, 46 (FIG. 6), are connected to balloon 60 for
 automatically unfurling the balloon from a folded collapsed insertion
 configuration to an expanded use configuration.
 The means for maintaining contact surface 62 of balloon 60 in engagement
 with the patient's heart during a cardiac jump start as described herein
 includes inflation componentry 72 operatively connected to balloon 60 via
 hose 70. Inflation componentry 72 includes a valve device 74 which is
 connected to a suction source or vacuum generator 76 and to a source 78 of
 pressurized fluid such as water, saline solution or a gas such as air or
 carbon dioxide. In response to signals from a control unit 80 such as a
 specially programmed microprocessor, pressure source 78 and valve device
 74 pressurize balloon 60 to a predetermined pressure during an electrical
 cardiac stimulation procedure, whereby contacts or electrodes 64 are
 maintained in electrically conductive contact with a patient's heart.
 Alternatively, during mechanical heart stimulation as described herein,
 control unit 80 activates valve device 74 to periodically connect balloon
 60 to pressure source 78 and alternately to suction source 76, whereby
 balloon 60 is rapidly and forcefully inflated with a predetermined
 periodicity.
 Control unit 80 is provided with setting knobs 82 for enabling a
 preselection of an inflation pressure of balloon 60 and for varying the
 rate and maximum pressure that is applied to balloon 60 upon proper
 disposition thereof in the intrapericardial space about the heart.
 As further depicted in FIG. 8, a plurality of sensor electrodes 84 is
 disposed on contact surface 62 of balloon 60 for monitoring natural
 voltages of a cardiac cycle. Sensor electrodes 84 are connected to EKG
 processing circuitry 86 via leads 88. According to conventional signal
 processing techniques, circuitry 86 generates a signal indicative of the
 patient's heart activity and displays the signal via a cathode ray tube
 (CRT) or video screen 90. Sensor electodes 84 and EKG processing circuitry
 facilitate the monitoring of heart activity during a heart resuscitation
 or beat regularization procedure as described below.
 In a surgical method for reactivating a malfunctioning heart, e.g., a
 stopped heart or a dangerously arrythmic heart, balloon 60 is inserted
 into an intrapericardial space about the patient's heart, as discussed
 above with reference to FIGS. 5 and 7A-7C. Upon deployment of balloon 60
 in the intrapericardial space, the balloon is inflated to place electrodes
 64 in electrically conductive contact with the heart. Then, a
 defibrillating type voltage produced by a generator 92 of voltage source
 68 is conducted via leads 66 and electrodes 64 to the patient's heart.
 Upon the conduction of the defibrillating type voltage to the patient's
 heart, heart action is monitored via electrodes 84, processing circuitry
 86 and CRT 90 for a predetermined period. If it is determined at that
 juncture that the patient's heart has started but with an insufficiently
 strong action, input provided to control unit 80 via setting knobs 82
 induces that unit to control valve device 74 so as to inflate balloon 60
 forcefully in synchronism with a heart contraction. Synchronism may be
 achieved, for instance, by providing control unit 80 with input from a
 blood pressure and pulse sensor 94 (including, e.g., a separate pressure
 cuff). Alternatively, if balloon 60 is sufficiently inflated, control unit
 80 may receive input from EKG processing circuitry 86. In either case,
 control unit or microprocessor 80 determines when a heart contraction is
 about to occur and opens valve device 74 to induce a flow of pressurizing
 fluid along hose 70 to balloon 60. The placement of a compressive pressure
 on the heart to thereby increase pumping action may alternatively be
 initiated manually by providing a triggering signal to control unit 80 via
 setting knobs or input 82.
 Balloon 60 may be at least partially deflated upon conduction of the
 defibrillating type voltage to the heart and prior to the monitoring of
 the heart action. The deflation may be only partial in the event that the
 heart action is monitored via sensor electrodes 84 and EKG processing
 circuitry 86. The deflation may be greater where the cardiac activity is
 determined via a conventional EKG device separate from balloon 60 and
 electrodes 84.
 To further instill a regular heart beat, a pacemaker type periodic voltage
 is produced by a generator 96 included, together with generator 92, in
 voltage source 68. The pacemaker type voltage is applied to the patient's
 heart via contacts or electrodes 64 upon an inflation of balloon 60
 sufficient to ensure electrically conductive engagement between the heart
 tissues and the electrodes. Control unit 80 regulates the pressurization
 of balloon 60 via valve device 74 and pressure source 78.
 The pacemaker type voltage may be applied after a defibrillating procedure
 as described hereinabove and after periodic cuff inflation to strengthen
 the heart beat. Control unit 80 determines by the activation of a switch
 98 (FIG. 9) whether a defibrillating type voltage or a pacemaker voltage
 is applied to the cardiac tissues.
 As described hereinabove with reference to FIGS. 7A-7C, the insertion of
 balloon 60 into the intrapericardial space may be implemented using
 hypodermic type needle 34. Needle 34 is inserted through a skin surface
 and into the intrapericardial space, balloon 60 being injected in the
 collapsed configuration through the needle into the intrapericardial
 space. As further discussed hereinabove with reference to FIGS. 7A-7C,
 dilating device 52 may be provided for facilitating the insertion of
 balloon 60 into the intrapericardial space. Needle 50 is partially
 inserted through the skin surface and into the intrapericardial space and
 a distal end portion of dilating device 52 is placed into the
 intrapericardial space via the needle upon the partial insertion thereof
 into the intrapericardial space. Dilating device 52 is subsequently
 expanded and balloon 60 inserted into the intrapericardial space through
 the expanded dilating device.
 As illustrated in FIG. 10, a modified intrapericardial assist device 100
 comprises a balloon 102 having a predetermined size and shape in an
 expanded configuration so that the balloon is capable of being disposed in
 an intrapericardial space about a heart. Inflation componentry including a
 tubular member 104 and a reversible pump 106 is operatively connected to
 balloon 102 for inflating the balloon from an unfolded collapsed insertion
 configuration to the expanded configuration. Also, a feed or drip tube 108
 is operatively connected to balloon 102 for delivering a lubricant 110
 from a reservoir 112 to an external surface 114 of balloon 102 upon
 disposition of the balloon in the intrapericardial space. A manifold 116
 may be provided in or along balloon 102 for delivering the lubricant 110
 to a plurality of apertures or outlets 118 along surface 114. Lubricant
 110 may take the form of a saline solution provided with corticosteroids
 for inhibiting or even preventing the formation of adhesions in the
 pericardial space.
 The lubricating componentry of FIG. 10 may be incorporated into any of the
 embodiments discussed above. Conversely, componentry from the above
 embodiments may be added to the embodiment of FIG. 10. For example, assist
 device 100 may include, as shown in FIG. 2, spring elements or ribs 30 and
 32 which can be bent into a curled configuration (see FIG. 3) but which
 tend to resume their C-shaped expanded configurations when cuff 12 is
 placed into an intrapericardial space during a cardiopulmonary
 resuscitation procedure. Spring elements or ribs 30 and 32 (FIG. 2)
 automatically unfurl balloon 102 (FIG. 10) from a folded collapsed
 configuration to an unfolded collapsed configuration.
 Reversible pump 106 automatically and periodically inflates and alternately
 deflates balloon 102 upon a disposition thereof into the intrapericardial
 space. Pump 106 may include the elements illustrated in FIG. 1, namely,
 control unit 22, valves 16, suction source 18 and pressure source 20.
 As discussed above with reference to FIG. 8, an array of electrical
 contacts or electrode wires 64 (FIG. 8) may be disposed on an inner
 contact surface 120 of balloon 102 (FIG. 10) for conducting electrical
 energy to the patient's heart upon an insertion of balloon 102 into the
 intrapericardial space. The delivery of lubricant 110 (FIG. 10) to the
 intrapericardial space is useful in the embodiment of FIG. 8, where a hose
 70 extends to balloon 60 for maintaining the balloon in an inflated state
 and thereby maintaining the balloon's contact surface 62 in adequate
 engagement with the patient's heart during the application of electrical
 energy to the heart via voltage source 68, transmission leads 66 and
 electrical contacts or electrodes 64. Where balloon 60 must be maintained
 in the pericardial space for an extended period, a saline solution
 provided with corticosteroids is advantageously delivered to the
 intrapericardial space for at least inhibiting the formation of adhesions.
 In assisting a malfunctioning heart with the intrapericaardial assist
 device 100 of FIG. 10, balloon 102 is inserted into an intrapericardial
 space about a heart disposed in the space. Subsequently, balloon 102 is
 inflated in the intrapericardial space to place a compressive pressure on
 the heart sufficient to force blood from the heart. In addition, lubricant
 110 is fed to the intrapericardial space after insertion of balloon 102
 into the space. Lubricant 110 is fed to the intrapericardial space by
 dripping the lubricant via gravity flow along feed tube 108. The inserting
 of balloon 102 into the intrapericardial space is accomplished via a
 hypodermic type needle 34 (FIGS. 3 and 4), as discussed above with
 reference to FIGS. 7A-7C. The insertion may be accomplished under direct
 vision, where a distal end of an endoscope (not shown) is inserted into
 the intrapericardial space.
 It is to be noted that an intrapericardial assist balloon as described
 hereinabove can be used not only where a heart is stopped but also where
 the heart is functioning poorly. For example, where a patient is a
 candidate for a heart transplant, a cardiac assist balloon as disclosed
 herein may be implanted into the intrapericardial space for an extended
 period of time while the patient awaits for a donor heart.
 As illustrated in FIG. 11, an intrapericardial assist device comprises a
 pair of alternately inflatable and collapsible balloons 160 and 162
 connected to one another so that the balloons together take on a cuff
 configuration 164 in an inflated or expanded state, as shown in FIG. 11.
 Balloons 160 and 162 are connected via respective tubes 166 and 168 to
 respective pressure sources 170 and 172.
 As illustrated in FIG. 12, pressure sources 170 and 172 each include a
 valve component 174 and 176. Valve components 174 and 176 are each
 connected to a common suction source or vacuum generator 178 and to a
 source 180 of pressurized fluid such as water, saline solution or a gas
 such as air. In response to signals from a control unit 182, valve
 components 174 and 176 periodically connect balloons 160 and 162 to
 pressure source 180 and alternately to suction source 178, whereby
 balloons 160 and 162 are rapidly and forcefully inflated with a
 predetermined periodicity.
 It is to be noted that control unit 182 operates valve components 174 and
 176 so as to vary the onset, the duration, and/or the rate of fluid flow
 to balloons 160 and 162. This measure of control enables unit 182 to
 differentially infate balloons 160 and 162, for example, to different
 maximum pressures. Such a mode of operation is desirable when a patient is
 afflicted with a sticky heart valve, aortic stenosis, or other condition
 leading to different pressures in the two ventricles.
 Control unit 182 may be provided with setting knobs (not illustrated) for
 varying the rates and maximum pressures that are applied to balloons 160
 and 162 upon proper disposition thereof in the intrapericardial space
 about the heart.
 Spring elements or ribs 184 and 188 are disposed in walls of balloons 160
 and 162 for unfurling balloons 160 and 162 from a folded or furled
 configuration to an expanded configuration upon a placement of cuff 164
 into an intrapericardial space.
 The deployment of cuff 164 and accordingly balloons 160 and 162 is
 implemented according to the procedure described hereinabove with
 reference to FIGS. 3 and 4. The embodiment of FIGS. 11 and 12 may
 incorporate any of the various features described hereinabove with respect
 to FIGS. 1-10.
 FIG. 13 illustrates a medical device 208 for use in performing surgery as
 discussed below with reference to FIGS. 14A through 14D to improve cardiac
 function in part by reducing the effective volume of the ventricles and in
 part by repeatedly exerting a compressive force on the reduced-volume
 ventricles to force blood out of the ventricles during a systolic phase of
 a cardiac cycle. The compressive device of FIG. 13 includes a cardiac
 clamp 210 in the form of a plurality of elongate prongs or tines 212
 connected in a substantially circular or oval configuration to a base 214.
 Prongs 212 have an inherent spring bias which tends to spread the prongs
 into a conical configuration as depicted in FIGS. 13 and 14B. Prongs 212
 are each provided with at least one tooth 216 which faces inwardly
 relative to the spread-open conical configuration.
 Device 208 further includes an inner tubular member 218 in which clamp 210
 is disposed in a collapsed configuration at the onset of a surgical
 procedure. More specifically, clamp 210 is disposed inside a distal end
 portion of tubular member 218 prior to an ejection of the clamp by a
 distally directed motion of a rod 220. Prior to use, rod 220 may be
 disposed outside of tubular member 218. It is preferable, however, that
 rod be disposed partially inside tubular member 218 during initial
 deployment thereof during a cardiac operation as discussed below.
 An elastic band 222 is disposed about tubular member 218 at the distal end
 thereof. A second tubular member 224 surrounds tubular member 218 for
 pushing band 222 off of the distal end of tubular member 218 as discussed
 below.
 As illustrated in FIG. 14A, a distal end portion of tubular member 218 is
 inserted through parietal pericardium PP into an intrapericardial space IP
 surrounding a patient's heart HT. Tubular member 218 may be deployed in an
 open heart surgical operation or alternatively in a minimally invasive
 operation. In the latter case, tubular member is inserted through a
 thoracoscopic cannula or trocar sleeve 226.
 Tubular member 218 is inserted from below the heart HT so that the distal
 end is pointed upwardly substantially parallel to the septum (not shown).
 After a proper positioning of tubular member 218, rod 220 is pushed in the
 distal direction, towards an apical portion AP of the heart HT to eject
 clamp 210, as shown in FIG. 14A. Upon the ejection of clamp 210, prongs
 212 automatically spread open under their inherent spring bias to form a
 conical configuration. The entire instrument assembly is then moved
 towards heart HT so that the opened clamp 210 surrounds apical portion AP,
 as illustrated in FIG. 14B. Subsequently, inner tubular member 218 is
 pushed forward, over clamp 210, as depicted in FIG. 14C. Prongs 212 are
 pressed inwardly in a camming type action so that teeth 216 bite into the
 myocardium of heart HT and anchor clamp 210 thereto. Continued forward or
 distal motion of inner tubular member 218 relative to clamp 210 serves to
 compress apical portion AP of heart HT, as shown in FIG. 14C. To some
 extent, prongs 212 pivot about the connecting points to base 214 in
 response to the camming action of tubular member 218.
 After the positioning and partial closure of clamp 210 about the apical
 portion AP of heart HT, outer tubular member 224 is shifted in the distal
 direction toward heart, while clamp 210 and inner tubular member 218 are
 maintained in position about apical heart portion AP. This relative motion
 serves to slide or push elastic band 222 off of tubular member 218 and
 onto the closed clamp 210. As illustrated in FIG. 14D, band 222 is left in
 place on clamp 210 to hold pongs 212 in a partially closed configuration
 compressing apical portion AP of heart HT and reducing the volume of both
 ventricles of the heart. The reduced volume makes the pumping action of
 the heart more efficient and improves blood circulation in individuals
 suffering from congestive heart failure or left ventricular hypertrophy.
 As further illustrated in FIG. 14D, a cuff-shaped balloon 228 is positioned
 in the intrapericardial space IP generally above the closed clamp 210. A
 tube 230 extends from balloon 228 to a pressure source (not illustrated).
 The structure, function and deployment of balloon 228 are as discussed
 above, for instance, with reference to FIGS. 1-10. In most cases, balloon
 228 is repeatedly and forcibly inflated to squeeze blood from the
 ventricles (not shown)of heart HT to assist in pulsatile blood
 circulation.
 As illustrated in FIG. 15, a cardiac assist device 232 comprises a first
 balloon 234 and a second balloon 236. Balloons 234 and 236 are optionally
 connected to one another and positioned in an intrapericardial space (not
 shown) in a single deployment or insertion operation. Balloon 234 assumes
 a generally cup shape in an inflated configuration, while balloon 236
 assumes a generally cylindrical configuration when inflated. Balloons 234
 and 236 are formed with slots or gaps 238 and 240 for purposes of
 facilitating disposition about heart HT. Tubes 242 and 244 extend from
 balloons 234 and 236 to respective pressure sources 246 and 248. Pressure
 source 248 periodically or repeatedly inflates and alternately deflates
 balloon 236 during a cardiac assist operation, while pressure source 246
 functions to inflate balloon 234 and to maintain that balloon in its
 expanded configuration during the cyclic inflation and deflation of
 balloon 236.
 FIGS. 16A through 16F illustrate an alternative procedure for reducing
 ventricular volume in a cardiac assist operation. As shown in FIG. 16A, a
 catheter 250 is inserted through a patient's vascular system into one of
 the ventricles LV and RV of the patient's heart HT, for example, the right
 ventricle RV. Catheter 250 has a leading end portion 252 which is
 steerable to enable a directing of a mouth opening 254 toward a sidewall
 SW1 of the patient's myocardium MYO. As shown in FIG. 16B, a wire 256 is
 ejected from catheter 250 through mouth opening 254 into and partially
 through myocardial sidewall SW1 upon a positioning of the mouth opening
 adjacent to the sidewall. Wire 256 is provided at a leading end with a
 plurality of barbs or arrow heads 258 preventing a withdrawal of the wire
 along its insertion path through myocardial sidewall SW1. Upon an
 embedding of barbs 258 in myocardial sidewall SW1, catheter 250 is
 manipulated to steer leading end portion 252 towards cardiac septum SPM,
 as illustrated in FIG. 16C. Then a second wire 260 is ejected from
 catheter 250 through mouth opening 254 and septum SPM into and partially
 through an opposing myocardial sidewall SW2, as depicted in FIG. 16D. Wire
 260 is provided at a leading end with a plurality of barbs or arrow heads
 262 preventing a detachment of the wire from myocardial sidewall SW2. Upon
 an embedding of barbs 262 in myocardial sidewall SW2, catheter 250 and
 wires 256 and 260 are manipulated to twist wires 256 and 260 about one
 another, as indicated by an arrow 264 and wire coils 266 in FIG. 16E. This
 twisting action exerts tension on wires 256 and 260 and is performed until
 sidewalls SW1 and SW2 are drawn sufficiently close to one another, as
 shown in FIG. 16F, to effectively reduce the volumes of ventricles RV and
 LV. Wires 256 and 260 are thereafter severed by any practicable technique
 including but not limited to shearing, laser cutting, etc. A cuff-shaped
 balloon 268 may then be deployed and operated as discussed above with
 reference to FIGS. 1-10, 14D and 15.
 A cardiac assist device as described above may additionally be provided
 with an ultrasonic sensor for use in monitoring blood flow in and/or from
 the ventricles upon deployment of the cardiac assist device. The
 ultrasonic (Doppler) sensor may be attached to the cardiac assist device,
 for instance, to the pulsating balloon.
 Although the invention has been described in terms of particular
 embodiments and applications, one of ordinary skill in the art, in light
 of this teaching, can generate additional embodiments and modifications
 without departing from the spirit of or exceeding the scope of the claimed
 invention. For example, there are alternative methods for inserting a
 balloon type cardiac assist device into the intrapericardial space. Such
 alternative methods include placing the balloon(s) through a laparoscopic
 cannula inserted either through the rib cage and alongside the sternum, or
 below the rib cage and above the diaphragm. The installation of an
 intrapericardial assist device may be accomplished nearly under direct
 vision, through a small incision beneath the ribs, without splitting any
 ribs.
 Furthermore, other mechanisms for closing a compressive device about a
 lower end of a patient's heart will be apparent to those skilled in the
 art. Such mechanisms will generally contemplate the conversion of an
 axially directed force to a compressive force. In one alternative design,
 instead of pushing tubular member 218 about the expanded clamp 210, a
 screw mechanism may be used to close, and possibly open, prongs 212. In
 another alternative design, a cup-shaped clamp has a plurality of relative
 movable leaves, as in a mechanical iris.
 It is to be noted, in addition, that device 208 may be used to place clamp
 210 about a part of the heart HT other than apical portion AP. Thus,
 device 208 may approach the heart HT from a different direction, for
 example, where it is desired to reduce the effective volume of the left
 ventricle only.
 Prongs 212 may be spring biased to close clamp 210. In that case, the
 inserting instrument is adapted to spread prongs 212 into a opened
 configuration in opposition to the action of inherent spring forces. When
 the opening force is removed, the clamp squeezes the hear muscle and
 compresses a portion of the heart.
 A catch may be provided on prongs 212 for holding band 222 on clamp 210
 after the disposition of band about the clamp.
 Accordingly, it is to be understood that the drawings and descriptions
 herein are profferred by way of example to facilitate comprehension of the
 invention and should not be construed to limit the scope thereof.