This application to the Patent Cooperation Treaty PTC, is based on a priority application in the U.S. Ser. No. 07/902.007 by Eitan Sobel filed on 22.06.92 now abandoned, and incorporated by reference in its entirety into a continuation-in-part application submitted in the U.S. on 30.04.93 for AN IMPLANTABLE CONDUCTING SYSTEM FOR THE HEART.

BACKGROUND - DESCRIPTION OF PRIOR ART

Living excitable cells are characterized by membrane electrical activity, which is basically a movement of different ions across the membrane, and the creation of an action potential, which can propagate along a cell, and induce an action potential in an adjacent cell. Without this intrinsic property of excitability, cell behaves like a long cable, in which there is a decay of the electrical voltage along the cell at a length constant called lambda, at which the voltage is 1/e (about a third) of its initial value. Lambda value depends on the type and size of the cell, and may varies considerably.

Special electrodes are implanted today for various artificial stimulation purposes. So far, two types of electrodes are known: point electrodes and area electrodes. Localized stimulation can be done either by point electrodes or by area electrodes, and consists of direct stimulation of a portion of a target tissue, while other portions of the target tissue get their stimuli by the "domino effect", in which the excitation of the cells that were directly stimulated by the electrodes is transmitted to neighboring cells, which get their stimuli from a "second hand" source, and their excitation is transmitted to other cells down the line. In contrast, generalized stimulation is almost always done with large area electrodes, which deliver high levels of energy sufficient enough to create global or near global excitation. Direct cell excitation requires a stimulation voltage above a threshold level. The stimulation voltage is directly related to the energy delivered, and inversely related to the surface area of the electrode.

AMOUNT OF ENERGY DELIVERED \/\ STIMULATION VOLTAGE

SURFACE AREA OF THE ELECTRODE

Point electrodes are usually build as a screw-in electrode. A point electrode is described by U.S. patent 4,876,109 by Mayer et al. (1989), in which the electrode penetrate the tissue surface, and is in a direct contact with the cardiac muscle cells. Large area electrodes, that are placed on the skin, are used today by external defibrillators. The more advanced i plantable defibrillators use area electrodes that are placed around the heart in the pericardial space as described by U.S. patent 4,030,509 by Helman et al. (1977). Another U.S patent 5,033,477 by Chin et al. (1991) describes a new method of implanting area electrodes with minimal amount of surgery. In the proposed procedure, the surgeon inserts electrodes via guide wires. The electrodes coil in the pericardial space in the form of a spring, and create a crimpble button, which is in a direct contact with the heart wall. The electrodes described by Chin et. al. are essentially another type of area electrodes, and therefore, suffer from all the disadvantages of area electrodes as mentioned below. Other newer types of area electrodes are found in newer generation of defibrillators, which have one of the electrodes placed in the target tissue cavity - the heart chambers as described by U.S. patent 5,014,696 by Mehra (1991). This electrode is a type of an area electrode, as the energy is transmitted via the blood tissue in the cavity to the target tissue - the heart wall, and the surface area of the endocardium is in fact the surface area of this electrode.

These types of electrodes suffer from a number of disadvantages: Point or Screw-in electrodes

1. The area directly stimulated via the point electrodes is small. Stimulation of other areas depends on the "domino effect".

2. Low levels of energy, such as the subthreshold levels of energy, do not cause excitation of cells. Therefore, there is no "domino effect", and the neighboring areas may not get any stimuli, as the stimulation voltage quickly diminished over a very short distance, depending on the lambda factor.

3. Suprathreshold stimuli require overcoming the resistance of the tissue around the point electrode. This concentration of energy in a very small area is responsible for macrophages and neutrophils degranulation with secondary fibrosis, tissue damage, and therefore, more resistance around the electrodes.

Area electrodes

1. Area electrodes can not deliver direct stimuli in an accurate manner to specific areas.

2. Therefore, higher levels of energy are needed to stimulate an unstable area.

3. The high levels of energy delivered through area electrodes, almost exclude their usage for delivering subthreshold levels of stimulation.

4. In most cases, there is a significant limitation in the proximity achieved by area electrodes to a target tissue.

5. Other non-target tissues may get an unnecessary stimuli, which may result in unnecessary damage.

The structures and materials used for different electrodes varies considerably. For example, U.S. patent 4,279,256 by Bucalo describes a nerve stimulation method by injectable electrode comprising of a plurality of electrically conductive bodied that are suspended in viscus substance for the purpose of nerve stimulation. Bucalo describes an area or rather a point electrode for a nerve, however, the characteristics of the medium used in his invention can be used for the conducting paths in the current invention. DESCRIPTION OF THE INVENTION: Definitions:

1. A target tissue. This term relates to the goals of the implantable conducting system. It is the tissue that will have an important and pivotal role in its operation. The implantable conducting system was designed to stimulate the target tissue, or to sense an impulse, and to be able to transmit it. The implantable conducting system was intended to have substantial treatment and diagnostic advantages for the target tissue. For example, U.S. patent 5,014,696 by Mehra (1991) describes an intracardiac electrode, of which the target tissue is the heart wall.

2. A non-target tissue. This term relates to the goals of the implantable conducting system. This tissue may be a bystander, and may even serve as a mediator, but this tissue is not the tissue that the implantable conducting system was designed for. Although, it may be used in the operation, it is not a crucial element, and has no intended advantage from it. For example, in U.S. patent 5,014,696 by Mehra (1991) describes an intracardiac electrode, of which the non-target tissue is the blood, which serves as a mediator.

3. Along. A path along a tissue can mean adjacent, beside, adjoining, on. atop, or buried within a target tissue.

4. Conductive medium. It is a material able to transmit energy impulses from and to a target tissue.

5. Disruption of continuity. A gap in the continuity of the target tissue created by a scar, fibrotic tissue, area with ischemia, or the like.

6. Tropism, Hypertrophy, Atrophy Tropism is the growth of a tissue in response to stimulation. Hypertrophy is an exaggerate growth response. Atrophy is a no growth response, and even a decrease in tissue mass.

Artificial conducting system represents a new concept of thoughts, that can not be easily accomplished with the current available electrodes. It is composed of conductive medium, in the form of an elongated path along a target tissue. The stimulation along a "line" or a "path" across a distance in a target tissue is new, and offers tremendous advantages. Moreover, the stimulation can be done in a certain direction along the path. In addition, the system offers a spectrum of direct contact and a spectrum of energies, that can be delivered by the system. Proximity to the target tissue is an important aspect of the system, and it is preferred, that the conductive medium is embodied by the target tissue cells. Finally, in contrast to the arbitrary location of most of the known electrodes, this system can be implanted in specific locations, which were chosen for a direct stimulation.

The techniques and materials for implanting the artificial conducting system are numerous. One way to implant these electrodes is by using Bucalo's injectable substrate (U.S. patent 4,279,256),

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comprising of a plurality of electrically conductive bodied, or similarly, by using conductive tinctures, liquids or colloids. This medium can be injected similar to a "tattoo" . Some other possible methods of creating conducting paths can use elongated bodies, cone shaped bodies, staples, nails, needles, wires and the like. The conducting system can potentiate the capabilities of impulses generator devices, and enable the development of different new devices. These new devices offer reduced energy expenditure, with less tissues damage. Reduced energy delivery will cause less foreign body reaction, less resistance, while the effectiveness of the stimulation will be augmented.

The most striking advantage is the ability of the artificial conducting system to deliver subthreshold stimuli along a path or a distance, leading to unexpected results. Subthreshold stimuli do not cause cells excitation, and therefore, do not initiate propagation of an action potential in the "do ini effect". Subthreshold stimuli are used today for increasing conductivity and for terminating various ventricular and supraventricular arrhythmias. U.S. patent 5,083,564 by Scherlag describes increased conductivity in the AV block, by delivering subthreshold stimuli to the AV node. Scherlag uses a state of the art screw-in lead electrode catheter, that is placed in a specific locations, such as near the His bundle. This way, increased conductivity in the His bundle or the AV junction is achieved . Alternatively, a better method of increasing conductivity can be achieved by using artificial conducting paths. The subthreshold stimuli can be transmitted along a path to a longer distances, achieving better accuracy and better results.

Subthreshold stimuli are used today for terminating various arrhythmias. Unfortunately, a high failure rate is reported with the current available electrodes, especially in ventricular tachycardia, when the reentrant sequence may encircle large segments of the heart wall. Alternatively, a better method of delivering subthreshold stimuli across the length of the critical areas is utilizing artificial conducting paths. Utilizing subthreshold stimuli in a reliable fashion can prevent the delivering of some unnecessary defibrillations to the heart. Subthreshold stimuli can be applied before the deterioration of an unstable rhythm to a malignant arrhythmia, resulting in a major

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improvement in the quality of life of the patients. Artificial conducting paths are also useful for delivering suprathreshold stimuli. Combining these electrodes to special "field pacers" devices will enable one to "pace" elongated fields in different target tissues. Although it requires more energy per impulse than the known point electrodes, conducting paths have many advantages and unexpected results, and can not be compared to point electrodes. For example, in atrial fibrillation, artificial conducting system can terminate the fibrillation, and ensure atrial contraction, while a regular pacer with a state of the art point electrode does not have a significant effect on the diseased atrium. Another way of achieving the same goal with less energy expenditure, may be using a regular pacer with a point electrode coinciding with conducting system stimulated at subthreshold level of energy.

The new artificial conducting system can operate at defibrillators' levels of energy, and result in a "localized defibrillator" , which delivers energies directly to electrically unstable areas of the heart. Delivering more energy via a larger system can cause global or near global excitation, and result in a "global / near global defibrillator". In addition, it is possible to combine different devices into one device, which is able to deliver a spectrum of energies from subthreshold to global stimulation. Another important aspect of the conducting system is an ability to sense and record electrical activity from different paths. This ability is an equivalent to constant electrophysiologic studies (EPS) that can transmit information to internal or external devices, and be used by physicians for better analysis of arrhythmic events. Artificial conducting track may be able to influence conduction without an energy source. It is known that the energy created by cardiac muscle fibers can be sensed and transmitted via electric wires. Therefore, it may be possible to transfer a high percentage of the cells own energy via special artificial conducting paths designed to have only minimal resistance and excellent conductivity. This technology can accomplish all the expectations of this invention without using an artificial energy source. Artificial conducting system has an effect on cardiac function by means of stimulating dysfunctioning areas of the heart, and restoring contraction. The above mentioned "field pacer" device is

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an example for restoring atrial contraction, and improving of cardiac function. The same is true for any dysfunctioning area of the heart. Creating artificial conducting system along the left ventricle or any other chamber, with or without special devices, can increase conduction along the implantable conducting paths. Ensuring simultaneous contraction of a chamber can significantly increase ejection fraction, and increase output. This effect is in a contrast to the poorly synchronized contraction of the diseased heart with poor left ventricular ejection fraction and decreased cardiac output.

Other benefits such as changing tissue anatomy, improving organization of muscle fibers, creating compensatory tropism of contracting fibers, and increasing blood flow to the target tissue can also be expected. Alternatively, implanting the system may also break close loops of stimuli, and may prevent unnecessary hypertrophy of cardiac muscle in certain hypertrophic cardiomyopathies. In addition, the known effect of increased vascularization in the vicinity of pacers' point electrodes can be used with the current invention for treating and preventing ischemia.

OBJECTS AND ADVANTAGES

Accordingly, the objects and advantages of the invention can be summarized:

A) Using the artificial conducting system, which has a spectrum of paths' lengths in direct contact with a target tissue, with impulse generator devises, which are able to deliver a spectrum of energies, thereby creating a spectrum of stimulations such as:

1. Subthreshold stimuli.

2. Field pacing.

3. Localized defibrillation.

4. Global or near global defibrillation.

B) The artificial conducting system may have additional theoretical advantages and functions, such as:

1. Artificial conducting track may be able to function without an energy source.

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2. Artificial conducting system may have a long term effect on the anatomy, the organization and the tropism of target tissue.

3. Artificial conducting system may be used to induce vascularization and increase in blood flow to the stimulated areas.

4. Artificial conducting system can be connected directly to devices via "wires", however, other indirect connection like induction of an impulse from a distance, which is a well known phenomena in electricity, may be utilized.

5. This technology may be applied to other organs such as bladder, which may help in bladder emptying, or other organs and tissues such as stomach, bowels, skeletal muscles, nerves and brain.

C) Indications for implanting artificial conducting system are:

1. Increasing conductivity.

2. Decreasing conductivity by creating refractoriness.

3. Overcoming conduction blocks.

4. Connecting or crossing different target areas.

5. Terminating various arrhythmias.

6. Sensing and recording the electrically unstable areas.

7. Restoring contraction of organs and chambers.

8. Ensuring simultaneous contraction.

9. Increasing performance and efficiency of contraction.

10. Compensating function by preventing atrophy of unaffected areas, improving organization of fibers, and creating compensatory tropism of the contracting fibers.

11. Preventing unnecessary hypertrophy.

12. Increasing vascularization and blood flow.

D) The conducting system has the advantages of:

1. Reducing energy expenditure.

2. Proximity to the target tissue.

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3. Possible limited stimulation only to selective areas.

4. Possible ability to induce stimuli in a target tissue from a distance.

5. Minimizing unnecessary stimuli to non-target areas.

6. Less tissue damage to target and non-target tissues.

7. Increasing cardiac function.

8. Preventing and treating ischemia.

9. Improvement of quality of life.

DESCRIPTION AND FUNCTION OF THE DRAWING

Figure 1 describes an implantation of an artificial conducting medium via a catheter 27, using a special needle 28 to inject or to tattoo a conducting medium 29, in the form of a plurality of conductive particles into the heart wall 30, where it forms a conductive path 31. The conductive medium can be suspended in a suitable substance means 32, which can be conducting colloid, drugs, that prevent foreign body reaction, or the like. Figure 2 describes an implantation of cone shape particles 33 into the heart wall 34 via a catheter 35. The conductive medium can be suspended in a suitable substance means 36. Figure 3 describes an implantation of special staples 37 via a catheter 38, creating another form of an artificial conducting path in the heart wall 39. Figure 4 describes an implantation of an artificial conducting path via a catheter 40, firing special wires or pins 41 into the heart wall 42. Figure 5 describes an implantation of an artificial conducting path via a catheter 43, injecting special nails 44 into the heart wall 45. Figure 6 describes a special catheter 46 for the implantation an elongated wire 47 in the heart wall 48, which serve as an artificial conducting path. Figure 7 shows an elongated wire 49, which is attached to a target tissue 50. Figure 8 demonstrates multiple elongated wires 51, which are placed on the heart walls 52 forming a "basket" type electrode. Figure 9 describes an unipolar electrode 53 connected via a wire 54 to a device 55. Figure 10 describes bipolar electrodes 56 and 57, which most significantly stimulate the area in between the electrodes. These electrodes (56, 57) are connected via wires 58 and 59 to a device 60. Figure 11 describes a linear electrode

61, which presents a voltage gradient along its path, and is connected by a wire 62 to a device 63. Figure 12 describes multiple conducting paths type electrode 64 connected by a wire 65 to a device 66. Figure 13 shows a zone 67, with attached multiple conducting paths 68. These conducting paths 68 join together and create conducting path 69 attached to area 70. Figure 14 is similar to figure 13, however, an area 71 contains an area-type electrode 72, which is connected to conducting path 73 attached to area 74. Figure 15 shows an electrode 75 connected by a wire 76 to a device 77. A spectrum of direct stimulations are represented by areas 78 to 82, wherein area 78 can represent subthreshold level of stimulation, area 79 can represent "field pacing" level of stimulation, and area 80 to 82 can represent different defibrillation levels of stimulation. Figure 16 presents a possible finding during electrophysiologic studies (EPS), in which a region of slow conductivity or a scar 83 facilitate the development of a reentrant circuit 84. In this case, the implantation of the conducting path can be done in area 85 across the scar 83. Figure 17 shows an ectopic focus 86 found during electrophysiologic studies (EPS), which is responsible for the development of arrhythmogenic impulses 87. In this case, the implantation of the conducting paths can be done across the abnormal area 88. Figure 18a and figure 18b are an upper view and a lateral view of a target tissue respectively. A portion of the target tissue 89 is separated by a scar 90 or an ischemic area 90 from an adjacent portion of the target tissue 91. A conducting path 92 is bridging between the two portions of the same target tissue. Figure 19 shows two target tissues. A nerve 93 and a muscle 94 are separated by a small gap 95. A conducting path 96 is bridging between the two target tissues. Figure 20 represents a stimulation method to increase conductivity along the AV node 97, the His Bundle 98, and the Purkinje fibers 99. A device 100 and a wire 101 shown in the figure may be similar to the device suggested by scherlag (U.S. patent 5,083,564), but an electrode 102 is new, and consists of artificial conducting path 102. Figure 21 represents an heart with a diseased atrium 103. A pacer like device 104 is connected via a wire 105 to artificial conducting systems 106 and 107, which deliver "field pacing" levels of energy. Similarly, device 104 can be subthreshold stimulator, which can increase

conductivity in the atrium by delivering subthreshold levels of energy via the conducting paths 106, 107, while a device 108, a wire 109 and a point electrode 110 can be used as a regular pacer. Figure 22 represents an arrhythmogenic heart with a region of slow conductivity 111 or a scar 111. Creating artificial conducting system 112, and connecting these paths to a device 113, will enable the delivering of various levels of energy. Lower levels of energies can prevent and treat the arrhythmias at earlier stages. At low levels of energy the device 113 becomes a "subthreshold stimulator", and at higher levels of energy it becomes a "field pacer" and a "localized or a global/near global defibrillator". Figure 23 represents an heart with a region of slow conductivity or a scar 114. Creating an artificial conducting system 115 may prevent arrhythmias by itself, without an energy source device. Figure 24 represent a possible short term effect of the artificial conducting system on heart function. The contraction of a chamber in drawing 116 to 120 is ineffective, since it shifts blood from one side of the chamber to the other. Figure 25 is in contrast to figure 24. The contraction in drawing 121 to 125 is simultaneous, and therefore effective, with better ejection fraction and cardiac output. Figure 26 represent a possible usage of the invention in a muscular structure. The artificial conducting system 126 is implanted in the urinary bladder 127, and connected via a wire 128 to a device 129. Triggering a switch 130, which can be beneath the skin, will operate the system, and can create a contraction in the urinary bladder 127.

SUMMERY, CONCLUSION, RAMIFICATION AND SCOPE

The invention is a new elongated type of electrode implanted along a target tissue. Although, the technologies and the mediums of the electrodes may vary, this type of electrode has unprecedented advantages in the treatment of the heart and other organs diseases. Thus, the scope of this invention should be determined by the claims and their legal equivalents, rather than by the examples given.

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