IMPLANTABLE CARDIAC ASSIST DEVICE WITH A PHASED ELECTRODE ARRAY
The present invention provides a fully implantable cardiac massage apparatus having a phased electrode array. The cardiac massage apparatus of the invention can provide both “active” contraction of the heat, wherein the device electrically stimulates the heart to contract, or “passive” contraction of the heart, wherein the device squeezes the heart in a coordinated fashion so that the heart is massaged in a natural fashion from the apex to the base of the heart.
This application is a continuation-in-part application of U.S. patent application Ser. No. 10/829,573 filed Apr. 22, 2004, which claims priority to U.S. Provisional Patent Application Ser. No. 60/464,766, filed Apr. 23, 2003, the applications being incorporated herein by reference, in their entirety.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENTNone
FIELD OF THE INVENTIONThe present invention relates to therapeutic devices to work in conjunction with a diseased or failing heart to satisfy the hemodynamic needs of a patient. More particularly, the invention relates to a fully implantable device for assisting a heart to pump blood by intermittently applying pressure to at least a portion of the ventricular surface of the heart (if not the entire surface), preferably both the atrial and ventricular surfaces, at predetermined or possibly pre-programmed intervals to assist the heart to provide adequate hemodynamic output by sensing demand of the human body. In short, the present invention assists the maintenance of, or reestablishes, the normal contraction sequence of a healthy heart.
The present device is designed to restore to normal the electrical excitation pathways and mechanical contraction sequence of the failing heart. Where necessary, this restores the normal spread of electrical excitation pathways with a phased array electrical stimulation coupled with a phased array mechanical compression to restore the normal excitation/contraction sequence to a failing heart.
BACKGROUND OF THE INVENTIONThe human heart is a very complex organ that relies on both mechanical and electrical operation in order to perform properly. As with any complex mechanism, problems can and often do arise, with the heart. For example, areas of the ventricle may lose their normal excitation pathways causing some parts of the ventricle to not contract when they are supposed to, losing, thereby, the circular compression and allowing some areas to “bulge.” This decreases efficiency. These areas of heart muscle are intrinsically contracting mechanically, but lack the correct electrical input. In addition, in some failing hearts the muscle of the heart no longer contracts the ventricles to a sufficient extent. Insufficient ventricular contraction can produce a dangerous reduction in the amount of blood flow.
Numerous attempts have been made to assist these diseased or failing hearts by applying external pressure directly to the heart. One such example is direct manual compression of the heart by a person's hand during open chest cardiopulmonary resuscitation. Often, however, the patient requires cardiac or circulatory support or assist for extended periods of time, such as hours, days, weeks, or for the rest of the patient's life. Thus, manual manipulation of the heart is not a solution to the problem in most cases.
Mechanical devices have been developed to apply external pressure directly to the heart. Some of these devices utilize an inflatable liner that surrounds the heart. For example, U.S. Pat. No. 5,119,804 Anstadt discloses a cup that is provided with an elastomeric liner. The heart is held in place within the liner, which is cyclically inflated and deflated to apply external pressure to the heart. While this device provides an improvement in hemodynamics for a diseased or failing heart, the device is not fully implantable. U.S. Pat. No. 5,131,905 Grooters and U.S. Pat. No. 6,238,334 Easterbrook, III et al. are further examples of external (as opposed to implantable) cardiac assist devices.
U.S. Pat. No. 6,464,655 Shahinpoor, at FIG. 6d and FIG. 7, illustrates an embodiment of the “Electrically-Controllable Multi-Fingered Resilient Heart Compression Device” disclosed therein. In the embodiment shown artificial muscles, specifically electro-active polymers, are used to create “soft fingers” that can be directly electrically powered and computer controlled by wires. See eg., U.S. Pat. No. 6,464,655 at column 8, lines 19-38,: The teachings of Shahinpoor are specifically incorporated by reference herein.
Another shortcoming inherent in the prior art devices results from the fact that relatively high pressures are applied almost exclusively to the central portion of the ventricles' outer surfaces. This causes the heart to deform into an unnatural, generally hourglass, shape and may even eventually cause trauma (e.g., bruises) to the heart, especially if one of the prior art devices is operated for an extended period of time.
SUMMARY OF THE INVENTIONThe present invention provides a fully implantable cardiac massage apparatus having a phased electrode array. The cardiac massage apparatus of the invention can provide both “active” contraction of the heat, wherein the device electrically stimulates the heart to contract, or “passive” contraction of the heart, wherein the device squeezes the heart in a coordinated fashion so that the heart is massaged in a natural fashion from the apex to the base of the heart.
The cardiac massage apparatus comprises a chamber array, the array comprising a series or locus of spaced-apart, fluidically coupled, chambers or helices. In one embodiment the array comprises helically-wound chambers, helices, or loops located closely adjacent or on the epicardium. The array further has fluid input and output ports. The chambers or helices collectively define an interior surface which closely conforms to the exterior surface of a heart when implanted. In another embodiment the array can be comprised of a series of spaced apart chambers that are vertically oriented with respect to the heart. In one embodiment the array fluid input port is located adjacent to the apex of the heart to be massaged and the fluid output port is located adjacent to the base of the heart to be massaged.
The cardiac massage apparatus also comprises a phased electrode array comprising a series of electrodes, the electrodes in contact with the heat and capable of providing electronic stimulation to the heart and capable of sensing cardiac output data of the heart. In one embodiment the electrodes are located in the interior surface of the chambers of the chamber array, in another embodiment they are separate from the chambers of the chamber array. The electrodes of the phased electrode array can also be connected to a phased electrode array controller means. The phased electrode array controller means is an electronically-powered microprocessor and can be a separate component, or be integral to either the cardiac activity sensor/input means or a controller means for the chamber array. The phased electrode array controller means controls the electrical discharge of the electrodes so that a coordinated electrical stimulation of the heart can be obtained to restore the hearts normal contraction sequence bringing about a normalization of the active phase of contraction
The cardiac massage apparatus of the present invention can also include coupled valve means, pump means, the chamber controller means, and the cardiac activity sensor/input means. The valve means is fluidly or hydraulically coupled to the chamber array input port and output port and, in turn, is coupled to the pump means. The pump means and valve means are both electronically coupled to the chamber controller means. In one aspect, the chamber controller means is an electronically-powered microprocessor. The chamber controller means of the present invention is adapted to actuate the pump means and valve means so that fluid is pumped substantially continuously through the input port while intermittently cycling the discharge. In this manner the fluidly-coupled chambers or helices are inflated and deflated starting at the apex of the heart and continuing toward the base of the heart to create a rhythmic cardiac massage which substantially imitates the natural contraction sequence of the heart.
A cardiac massage apparatus of the present invention further includes a cardiac activity sensor/input means which monitors or senses cardiac output. The cardiac activity sensor/input means sends the cardiac output data to both the phased electrode array controller means and the chamber controller means. Depending on the cardiac output data, the phased electrode array controller means and the chamber controller means can determine, based on preprogrammed parameters for cardiac output data, whether the cardiac massage apparatus needs to trigger either an “active” contraction of the heart by signaling the activation of the phased electrode array, or a “passive” contraction of the heart by having the chamber array contracting in a controlled fashion around the heart.
In a further embodiment, the massage apparatus can include a separately-implanted source of electrical energy such as, for example, a rechargeable battery and an optional fluid reservoir.
BRIEF DESCRIPTION OF THE DRAWINGSSome of the features and advantages of the invention having briefly been stated, others will appear from the detailed description which follows, when taken in connection with the accompanying drawings in which:
Before the embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including”, “having” and “comprising” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items and equivalents thereof.
DETAILED DESCRIPTION OF THE INVENTION The present invention provides a cardiac massage apparatus that provides assistance to a heart. The cardiac massage apparatus does not interfere with the normal contraction pattern or rhythm of the heart as long as the “normal” pattern provides sufficient cardiac output of blood (e.g., from about 1.5 to about 3 liters per minute) to sustain and support the activities in which the patient wishes to engage. As shown in
One embodiment of the present invention is shown in
Also shown in
Pump 112 causes a fluid, preferably an incompressible, low viscosity, biocompatible fluid such as saline to flow into the individual helices 108 starting at the heart's apex 102 and flowing toward its base 104. (It is conceivable that compressed gas could be used to activate the helices or chambers according to this invention). This creates a wave form or wave front which travels from the apex toward the base which causes the heart (specifically the ventricles) to contract in rhythmic fashion. This contraction wave form tends to mimic normal cardiac depolarization but with enhanced or accelerated fluid blood flow from the ventricles. The speed of pump 112 (which preferably is either a kinetic or centrifugal pump, a peristaltic or positive displacement pump but may be of any type including axial turbine or a radial pump) is coordinated with pressure regulator 110 to create a sequence or series of wave forms or pulses of fluid in chambers 108 causing at least the ventricles (but preferably both the ventricles and the atria) to be rhythmically massaged or compressed. In this manner cardiac output is substantially enhanced with the assistance of this device. A device of this invention has the capability of assisting left and right ventricles (i.e., compressing or massaging) essentially simultaneously or sequentially.
The intensity of the compression step can be adjusted by adjusting pump speed and pressure regulator 110 timing. The intensity of the compression step can also be adjusted by the selection of stiffness and diameter of the bladder or tube elements used to create the array 106. The number of chambers 108 wrapped around heart 100 and their separation distance (discussed above), also determines the intensity and extent of assist provided to the heart. One skilled in the art will appreciate that some amount of experimentation regarding bladder characteristics may be needed to optimize the natural pumping efficiency of the heart using a device of this invention.
The cardiac assist device also contains a phased electrode array 490 having a series of electrodes 500. The electrodes 500 can be positioned on the interior (facing the heart) of the tubing array 106 as shown or can be placed adjacent the heart in other positions. The electrodes 500 are electronically connected to a phased electrode array controller means 502 by means of wires 506. In one embodiment the electrodes can also be connected to a cardiac activity sensor/input means 115. To aid in the clarity of the drawing the wires 506 to only a few of the electrodes 500 are shown, though all the electrodes have such wires. The phased electrode array controller means 502 is suitably a microprocessor and is programmed to receive input information as to the status and performance characteristics of heart 100. The controller 502 can receive this information from feedback from the electrodes 500 themselves and/or from the cardiac activity sensor/input means 115 by way of the connection 504. In another embodiment, the phased electrode controller means can be the same microprocessor (i.e. same part) used for the controller 114 for the tubing array, and can also be the same microprocessor as the sensing/input means. Assuming heart 100 is providing adequate cardiac output i.e., it is beating sufficiently frequently, with sufficient efficiency, the assist system shown in the
It also is to be appreciated that the physiological factor (or factors) observed or monitored by sensor/input means 115 to provide input to control means 114 may include many (if not all) of the parameters normally observed appurtenant to electrical sensing and/or pacing of the heart. Thus general body activity, oxygen saturation, pulse, peak-to-peak T-wave separation and numerous other indicia of cardiac activity may be observed in order to trigger e.g., via the microprocessor 114, the use of the present device. Appropriate input leads, whether internal or external to the heart, are selected depending upon the parameter(s) of cardiac activity selected to be observed or monitored. To some extent, the overall placement and configuration of the chamber array may be modified in view of the physiologic factor or factors chosen to be monitored.
It is possible that the sensor/input means 115 can have sensors separate from the electrodes 500 that measure cardiac output i.e., blood flow or blood volume, directly. Various sensors e.g., cardiac sensing/pacing leads, which measure cardiac output directly or indirectly, are available from Medtronic, Inc., in Fridley, Minn., U.S.A. Cardiac output also can be measured using a sensor inserted into an artery at the wrist.
It also is within the contemplation of this invention that the input 115 to control means 114 could be the output from a cardiac pacemaker. Integration of the present device with a cardiac pacemaker would provide the advantage of e.g., fewer organ-electrode interfaces. It follows, of course, that a sophisticated pacemaker may control the pump and pressure regulator without the need for a second implanted control means (i.e., in the absence of control means 114).
It is understood that the device shown in
Referring to
Referencing
The Bourdon tube 402 arrangement is constructed to apply pressure in a coordinated and physiologic pattern about the heart in order to apply pressure to the needed location and timing sequence to aid the failing heart. A Bourdon tube 402 is a curved and partially flattened tube that tends to straighten out in proportion to thermal pressure. The unique feature of this is that the material properties of the Bourdon tube 402 in the non-pressurized state return to the “relaxed” or “non-compressive” state. Therefore when the Bourdon 402 tube is in a pressurized state from the input of fluid from pump 112, the tubes 402 contract the heart, and when they are not in a pressurized state, the tubes 402 recoil away from heart, facilitating the refilling of heart passively.
These Bourdon tubes 402 have a lining with the electrodes 500 positioned in a phased array to be able to electrically stimulate/pace the heart in a specific time and location if indicated to get the heart to “actively” contract on its own as needed
The present invention has the advantage of providing cardiac assistance or enhancement without creating the kind of blood/device interfaces characteristic of artificial hearts, implanted blood pumps, and other such mechanical, fluid-circulating assist therapies. Thus, blood/interface artifacts, e.g., damage to blood constituents, thrombus creation, and coagulation do not result because the present invention uses only the normal cardiac endothelium to interface with blood.
The present invention is also broadly applicable to cardiac muscle infirmities which are evidenced by weakened cardiac muscle wall and muscle aneurysms or bulges. Such muscular infirmities are evidenced by dyskinetic cardiac muscle segments (i.e., wall segments which do not reliably contract, and hypokinetic segments i.e., wall segments which contract too slowly. Utilization of the present invention with its cardiac cupping or enveloping structure tends to mitigate or eliminate these phenomena. Thus, in one aspect, the present invention is a method of mitigation of cardiac muscle infirmities including dyskinesia and hypokinesia, which method involves the steps of providing a heart-shaped, cup apparatus; deploying the cup apparatus so that it substantially envelopes a patient's heart evidencing muscle infirmities, the apparatus being located so as to provide exterior support thereto; and anchoring the cup apparatus to the patient's heart.
All patents, publications and references cited herein are hereby fully incorporated by reference. In the case of conflict between the present disclosure and the incorporated patents, publications and references, the present disclosure should control.
While the present invention has now been described and exemplified with some specificity, those skilled in the art will appreciate the various modifications, including variations, additions, and omissions that may be made in what has been described. Accordingly, it is intended that these modifications also be encompassed by the present invention and that the scope of the present invention be limited solely by the broadest interpretation that lawfully can be accorded the appended claims.
Claims
1. An implantable cardiac massage apparatus for providing assistance to a heart having an apex and a base, the apparatus comprising:
- a chamber array, the array comprising a series of spaced-apart, fluidically coupled chambers, the array having fluid input and output ports, wherein the input ports are located near the apex of the heart and the output ports are located near the base of the heart, and the chambers defining an inside surface which closely conforms to the external surface of a heart and;
- pressure regulator means, the pressure regulator means being fluidly coupled to the array input port and output port, the pressure regulator means also being fluidically coupled to;
- pump means, the pump means and the pressure regulator means being electronically coupled to;
- controller means, the controller means being adapted to actuate the pump means and the pressure regulator means so that fluid is pumped substantially continuously by the pump means to the input port and the pressure regulator means intermittently inflates and deflates the chambers starting at the apex of the heart to create a rhythmic message of the heart from its apex to its base thereby substantially imitating the natural contraction of the heart, the controller means being further adapted to receive sensor information input from a cardiac activity/sensor means;
- a phased electrode array comprising a series of electrodes, the electrodes in contact with the heart and capable of providing electronic stimulation to the heart;
- a phased electrode array controller means, the phased electrode array controller means being adapted to control the discharge of electrical stimulation of the phased electrode array; and
- wherein the cardiac activity/sensor means, the cardiac activity/sensor means being adapted to sense cardiac activity and input sensor information to the controller means and to input sensor information to the phased electrode array controller.
2. The apparatus of claim 1 which further includes an implantable reservoir means fluidly coupled to the chamber array.
3. The apparatus of claim 1 which further includes an implantable source of electrical energy electronically coupled to the pump means.
4. The apparatus of claim 1 electronically coupled to the controller means.
5. An apparatus of claim 1 wherein the pressure regulator means comprises a relief valve.
6. An apparatus of claim 1 wherein the pump means comprises a kinetic pump or axial turbine.
7. A method of mechanically assisting a heart comprising the steps of:
- deploying an apparatus of claim 1 about the external surface of the heart;
- activating the apparatus by energizing the controller means and in turn the pump means so as to cause fluid to flow through the apparatus;
- pulsing fluid flow through the apparatus by operating the pressure regulator means the fluid flow starting at the apex of the heart and passing to the base of the heart thereby rhythmically massaging the heart from the apex toward its base to enhance the heart's fluid output in a manner similar to unassisted cardiac discharge.
8. An implantable cardiac massage apparatus for providing assistance to a heart having an apex and a base, the apparatus comprising:
- a chamber array, wherein the chamber array comprises elastic Bourdon tubes, the array comprising a series of spaced-apart, fluidically coupled chambers the array having fluid input and output ports, and the chambers defining an inside surface which closely conforms to the external surface of a heart and;
- pressure regulator means, the pressure regulator means being fluidly coupled to the array input port and output port, the pressure regulator means also being fluidically coupled to;
- pump means, the pump means and the pressure regulator means being electronically coupled to;
- controller means, the controller means being adapted to actuate the pump means and the pressure regulator means so that fluid is pumped by the pump means to the input port and the pressure regulator means intermittently inflates and deflates the chambers starting at the apex of the heart to create a rhythmic message of the heart from its apex to its base thereby substantially imitating the natural contraction of the heart, the controller means being further adapted to receive sensor information input from a cardiac activity/sensor means;
- a phased electrode array comprising a series of electrodes, the electrodes in contact with the heart and capable of providing electronic stimulation to the heart;
- a phased electrode array controller means, the phased electrode array controller means being adapted to control the discharge of electrical stimulation of the phased electrode array; and
- wherein the cardiac activity/sensor means, the cardiac activity/sensor means being adapted to sense cardiac activity and input sensor information to the controller means and to input sensor information to the phased electrode array controller means.
9. An implantable cardiac massage apparatus for providing assistance to a heart having an apex and a base, the apparatus comprising:
- a helically wound tubing formed into an array, the array having a fluid input port located near the apex of the heart and a fluid output port located near the base of the heart, and the array defining an inside surface which closely conforms to the external surface of a heart and;
- pressure regulator means, the pressure regulator means being fluidly coupled to the array input port and output port, the pressure regulator means also being fluidically coupled to;
- pump means, the pump means and the pressure regulator means being electronically coupled to;
- controller means, the controller means being adapted to actuate the pump means and the pressure regulator means so that fluid is pumped substantially continuously by the pump means to the input port and the pressure regulator means intermittently inflates and deflates the helically wound tubing starting at the apex of the heart to create a rhythmic message of the heart from its apex to its base thereby substantially imitating the natural contraction of the heart, the controller means being further adapted to receive sensor information input from a cardiac activity/sensor means;
- a phased electrode array comprising a series of electrodes, the electrodes in contact with the heart and capable of providing electronic stimulation to the heart;
- a phased electrode array controller means, the phased electrode array controller means being adapted to control the discharge of electrical stimulation of the phased electrode array; and
- wherein the cardiac activity/sensor means, the cardiac activity/sensor means being adapted to sense cardiac activity and input sensor information to the controller means and to input sensor information to the phased electrode array controller means.
Type: Application
Filed: Oct 9, 2006
Publication Date: Jul 19, 2007
Inventors: Edward Coleman (Green Bay, WI), Gerard Coleman (Galveston, TX), William Neill (Elm Grove, WI)
Application Number: 11/539,763
International Classification: A61N 1/362 (20060101);