Abstract:
An apparatus and method for Cardiac Resuscitation of an arrested heart, for Percutaneous Internal Direct Epicardial Defibrillation, Cardioversion and Pacing with electrodes placeable directly into the chest cavity onto the epicardium via a device entering the chest in a specific area of the anterior chest wall via blunt dissection rapidly creating a passage of negligible size in the chest wall for the introduction of the electrodes, without the need for thoracotomy or for sternotomy and without requiring the use of sharp surgical instruments and without causing pneumothorax. Due to its rapidity of implementation, its safety and simplicity of application, the device can be used by Paramedics in the field at the scene of a cardiac arrest, where the resuscitation efforts are more likely to succeed, for internal direct epicardial defibrillation, cardioversion and pacing.

Description:
FIELD OF INVENTION  
         [0001]    This invention relates to electrical cardiac therapy devices, specifically to emergency defibrillators, cardioverters and pacemakers.  
         BACKGROUND-DESCRIPTION OF PRIOR ART  
         [0002]    Electrical therapy is nowadays commonly used in cardiac therapy, specially in cardiac resuscitation. Defibrillation, cardioversion and pacemaker therapy play a major role in cardiac resuscitation. Defibrillators and cardiac pacemakers are indeed common devices in the emergency armamentarium. Electrical therapy has proved over the last two decades to be indeed often lifesaving in cardiac arrest settings. Cardiac arrest can results from a variety of cardiac arrythmias all amenable to electrical therapy. These arrythmias include ventricular fibrillation, ventricular tachycardia, ventricular asystole and high degree heart blocks. A defibrillator is a device that administers a controlled electrical shock to patients to terminate a cardiac arrhythmia. The technique of administering the electrical shock is usually referred to as defibrillation if it used to terminate Ventricular Fibrillation or pulseless Ventricular tachycardia. and referred to Cardioversion if it is administered for other cardiac arrythmias, typically atrial fibrillation, atrial flutter, or ventricular tachycardia. Typically, in defibrillation the electrical shock is unsynchronized with the cardiac cycle while in cardioversion the electrical shock is delivered in synchronization with the cardiac cycle, at a specific electrical stage of the cardiac cycle.  
           [0003]    The defibrillator basically consists of a charging circuit that gradually builds electrical energy to a preset level on a storage circuit. The storage electrical energy is then delivered to the patient through a discharge circuit. The electrical stored energy is delivered via conductive paddles applied to the chest or back of a patient in the External Defribillator. Another type of Defibrillator is the Automatic Implantable Cardioverter-Defibrillator which consists of a pulse generator with both sensing and shocking electrodes. In the Automatic Implantable Defribillator the shocking electrodes are usually two epicardial patches placed in anteroposterior position over the heart surface or one epicardial patch and another electrode, the so called transvenous spring electrode, placed in the right ventricular apex, all implanted by thoracotomy or sternotomy i.e. by surgical opening of the chest. Rarely direct epicardial defibrillation. i.e. defibrillation with two epicardial paddles applied directly over the heart in anteroposterior position is implemented, the indications being traumatic cardiac arrest, open chest surgery or, extremely rarely, in medical cardiac arrest during open chest cardiac massage.  
           [0004]    The energy required for Direct or Internal Defibrillation of the heart in these cases is by far less than the energy required with External Defibrillation. Due the fact the paddles are directly applied over the heart obviously the impedance, i.e. the resistance to current flow, is greatly reduced in respect to the commonly used External Defibrillators. There are indications that Direct or Internal Defibrillation is more effective that External Defibrillation. Unfortunately due the fact that Direct or Internal Defibrillation can be carried out only in patients victim of cardiac arrest via thoracotomy, i.e. via the surgical opening of the chest, its applications are severely limited and, practically, it can be carried out only in case of traumatic cardiac arrest or in patients whose heart arrested during cardiac surgery in the operating room. Due to the fact that Direct or Internal Defibrillation via thoracotomy cannot obviously be carried out in the field at the site of a cardiac arrest nor in most cases in Emergency Departments as thoracotomy is a highly invasive procedure with high morbidity and mortality, the usefulness of Direct of Internal Defibrillation is restricted to a very small number of patients leaving out the greater majority of patients victim of cardiac arrest.  
           [0005]    Pacemakers are medical devices that deliver an electrical stimulus through electrodes to the heart causing electrical depolarization and subsequent cardiac contraction. Emergency cardiac pacing is required in patients whose primary problem is cardiac impulse formation and /or conduction such as hemodynamically compromising unstable bradycardia, high degree of heart block, bradysistolic cardiac arrest and also refractory tachycardias. Emergency Temporary Cardiac Pacemakers are named according to the location of the electrodes and the pathway the electrical stimulus travels to the heart. They are named: Transcutaneous when the electrodes are placed on the skin of the anterior chest wall and back of a patient, Transvenous when the electrode tip is positioned in the right ventricle or right atrium or both, Transthoracic when the electrodes are placed through the anterior chest wall into the myocardium, i.e. the heart muscle, Epicardial when the electrodes are placed on the surface of the heart, Transesophageal when the electrodes are positioned within the esophagus.  
           [0006]    As Internal Defibrillation, Epicardial pacing, i.e. cardiac pacing with the electrodes placed directly onto the epicardium or through the epicardium, is almost exclusively carried out during open chest surgery for resuscitation of patients with penetrating chest trauma. Despite dramatic improvement has been reported following epicardial pacing, its application is restricted to only an handful of patient due to the obligate requirement of opening surgically the chest for placing the pacing electrodes onto the heart surface.  
           [0007]    No epicardial electrical therapy device, Defibrillator or Cardiac pacer is known to have the electrodes placed onto the heart surface without the surgical opening of the chest.  
         OBJECTS OF THE PRESENT INVENTION  
         [0008]    As above pointed out, there are studies documenting the dramatically superior efficacy of epicardial pacing versus the transcutaneous pacing, and there are strong indications that epicardial defibrillation carried out within a reasonable time of onset of a cardiac arrest is effective and indeed more effective than the presently normally used method of external defibrillation.  
           [0009]    At present time, epicardial defibrillation and or epicardial pacing can only be carried out via surgical opening of the chest with sharp instruments. Such a procedure, besides being associated with high morbidity and mortality, has the unavoidable drawback of having to be carried out only in operating rooms and rarely in Emergency Departments. Due to the invasiveness character of the procedure, epicardial defibrillation and or pacing is presently rarely carried out and only in cases when open chest cardiac massage via thoracotomy is carried out.  
           [0010]    It is an object of the present invention to provide an electric cardiac therapy device for defibrillation, cardioversion and pacing with at least one electrode being placeable directly onto the heart surface via introduction into the chest cavity with means of blunt dissection of the chest wall without surgically opening the chest.  
           [0011]    It is an object of the present invention to provide an electric cardiac therapy device for defibrillation, cardioversion and pacing with at least one electrode being placeable directly onto the heart surface via introduction into the chest cavity without the requirement of surgically opening the chest.  
           [0012]    The fundamental and unique feature of gaining access to the chest cavity and to the heart without surgically opening the chest, via blunt means for dissection and blunt means for entry into the chest cavity for the purpose of epicardial defibrillation and or pacing is not known in any prior art.  
           [0013]    The ability of gaining access to the chest cavity via blunt means for dissection and blunt means for entry into the chest cavity is critical in rendering epicardial defibrillation, cardioversion and pacing a procedure that can be practically implemented in large number of patients. The procedure can be carried out in patients in the field at the scene of a cardiac arrest where resuscitative efforts are more likely to succeed.  
           [0014]    It is an object of the present invention to provide an electric cardiac therapy device for defibrillation, cardioversion and pacing with at least one electrode being placeable directly onto the heart surface, such electrode placement being carried out safely via blunt means of dissection in a specific area of the chest wall without causing injuries to the chest wall structures, to the heart and to the other intrathoracic organs and without causing pneumothorax, i.e. collapsing of the lung.  
           [0015]    It is an object of the present invention to provide an electric cardiac therapy device for defibrillation, cardioversion and pacing with at least one electrode being placeable directly onto the heart surface rapidly and safely at the site of the cardiac emergency situation.  
           [0016]    Buckman and Badellino disclosed in their Pat. No. 5,484,391, No. 5,571,074 and No. 5,582,580, a method and apparatus for direct cardiac defibrillation and pacing associated with their disclosed direct manual cardiac compression device. The device of Buckman and Badellino is disclosed to be inserted into the chest cavity onto the heart via opening the chest via surgical means, precisely making an incision in the skin of an intercostal space and surgically separating the intercostal space for the purpose of inserting the device. The apparatus and method disclosed by Buckman and Badellino, although it presents some advantages over the open chest cardiac massage and over the implementation of epicardial defibrillation and or pacing via thoracotomy, still has the unavoidable drawback of having to be carried out by way of a surgical opening of the chest with a surgical knife with all the complications associated with the surgical opening of the chest and with the unavoidable disadvantage of having to be implemented only in a hospital setting, and not at the scene of a cardiac arrest where resuscitative efforts are more likely to succeed.  
           [0017]    It is an object of the present invention to provide an epicardial device for electrical cardiac therapy that can be used in association with all the cardiac resuscitation devices for percutaneous direct cardiac massage disclosed by Zadini et Al. in their issued Pat. No. 5/466,221, in their copending patent application Ser. No. 08/100,573 filed on Jul. 30, 1993 allowed and abandoned, in their copending patent application Ser. No. 08/600,306, a Continuation of patent application Ser. No 08/100,573, filed Feb. 12, 1996, now allowed, and in their copending patent application Ser. No. 08/555,589 filed on Nov. 13, 1995 and now pending. All the above references have the very important common feature of placing an expandable member into the chest cavity in front of the heart for the purpose of compressing and decompressing the heart via means of blunt dissection through the chest wall and blunt entry into the chest cavity. No other known resuscitation device or methods of cardiac resuscitation has the feature of placing the cardiac compression-decompression member for direct cardiac massage into the chest cavity by means of blunt dissection of the chest wall and blunt entry into the chest cavity.  
           [0018]    No other cardiac resuscitation device is known to have the feature of being operated safely effectively and swiftly at the scene of the cardiac arrest where the chances of survival are greater.  
           [0019]    The combination of the epicardial percutaneous device for electrical cardiac therapy with the cardiac resuscitation device for percutaneous direct cardiac massage makes epicardial defibrillation, cardioversion or pacing a practical procedure usable in conjunction and concurrently with direct cardiac massage as the arrested heart may respond to either electrical therapy or direct cardiac compression-decompression. As pointed out above, at present epicardial defibrillation and or pacing can only be carried out via surgical opening of the chest with sharp instruments. Such a procedure, besides being associated with high morbidity and mortality, has the unavoidable drawback of having to be carried out only in operating rooms and rarely in Emergency Department. Due to the invasiveness character of the procedure epicardial defibrillation and or pacing is presently rarely carried out and only in cases when open chest cardiac massage via thoracotomy is carried out.  
           [0020]    Due to its ability of being implemented with minimal invasiveness and safely without damaging intrathoracic organs including the heart owing to the features of gaining access to the chest cavity by blunt dissection and blunt entry, the potentially highly effective emergency procedure of epicardial defibrillation and/or pacing with the present invention can be implemented even at the scene of a cardiac arrest by trained personnel such as paramedics at the earliest time when its usefulness is greater.  
           [0021]    Again, the fundamental and unique feature of gaining access to the chest cavity and to the heart via blunt means for dissection of the chest wall and blunt means for entry into the chest cavity for the purpose of epicardial defibrillation and or pacing is not known in any prior art.  
           [0022]    It is important to point out that gaining access to the chest cavity with a sufficiently small size blunt means through the “trigonum sine pleura”, which is an area in the inner aspect of the anterior thoracic wall void of lung tissue and of its lining, i.e. pleura, guarantees, among the others, the unique advantage, in respect of methods of surgically opening the chest, of not causing the complication known as pneumothorax, i.e. collapse of the lung, which is an unavoidable complication when the chest is opened surgically.  
           [0023]    The ability of gaining access to the chest cavity via blunt means for dissection and blunt means for entry into the chest cavity is critical in offering the significant dual advantage of rendering two potentially highly effective procedures such as direct heart massage and direct epicardial electrical therapy concurrently practically implementable in large number of patients. Both procedures can be carried out in patients in the field at the scene of cardiac arrest where resuscitative efforts are more likely to succeed.  
       
    
    
     DRAWING FIGURES  
       [0024]    [0024]FIG. 1 shows a cross sectional view of an embodiment of the device with its stem tip within the chest cavity prior to deployment of the two electrodes on the epicardium.  
         [0025]    [0025]FIG. 2 shows a view of the two deployed electrodes on the epicardium ready for electrical therapy.  
         [0026]    [0026]FIG. 3 shows a cross sectional view of the thoracic cavity with the two electrodes deployed and positioned on the epicardium.  
         [0027]    [0027]FIG. 4 shows a cross sectional view of the thoracic cavity with an alternative form of the device of FIGS.  1  to  3  showing its single epicardial electrode and its other electrode applied on the skin of the back of the patient.  
         [0028]    [0028]FIG. 5 shows a cross sectional view of an alternative form of the electrical therapy device of FIG. 1 to  4  in combination with a percutaneous direct cardiac massager at rest, ready to be used..  
         [0029]    [0029]FIG. 6 shows a cross sectional view of a detail of the device of FIG. 5.  
         [0030]    [0030]FIG. 7 shows a cross sectional view of another detail of device of FIG. 5.  
         [0031]    [0031]FIG. 8 shows a cross sectional view of a chest of a patient with the device of FIG. 5 in use after penetration of its tip into the chest cavity and at an intermediate inflation stage of the expandable member.  
         [0032]    [0032]FIG. 9 shows a cross sectional view of a chest of a patient with the expandable member of device of FIG. 5 fully expanded.  
         [0033]    [0033]FIG. 10 shows a view of a device for opening a passage through the chest wall and entering the chest cavity by blunt dissection to enable the insertion of the electrodes into the chest cavity onto the epicardium.  
         [0034]    [0034]FIG. 11 shows the electrical component of the device of FIG. 10.  
         [0035]    [0035]FIG. 12 shows a schematic cross sectional view of an alternative form of the electrical therapy device of FIGS.  1  to  4  in combination with an alternative form of the percutaneous direct cardiac massager illustrated in FIGS. 5 through 9 at an initial stage of operation.  
         [0036]    [0036]FIG. 13 shows the device of FIG. 12 at a further stage of operation. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0037]    In that form of the present invention chosen for purpose of illustration an epicardial percutaneous device for electrical cardiac therapy indicated generally at 1200′ is shown in FIG. 1.  
         [0038]    As shown in FIG. 1, which is a cross sectional view of the device, the device, generally indicated at 1200′, is composed of two main components, stem member  1202 ′ and a set of two pairs of diverging electrode-ribs  1216 ′. Stem member  1202 ′, of general cylindrical hollow shape, comprises hollow stem  1203 ′, distal end or stem tip  1201 ′ and proximal end  1205 ′. Proximal end  1205 ′ of stem member  1202 ′, is securely connected to handle  1206 ′. Within hollow stem  1203 ′ is slideably mounted rod  1210 ′. Rod  1210 ′ is of generally cylindrical shape having an array of notches  1209 ′ on its proximal segment for engagement with locking tab  1246 ′, as it will be described below. Proximal ends  1231 ′ of diverging electrode-ribs  1216 ′ are firmly attached to distal end  1218 ′ of rod  1210 ′. Hollow stem  1203 ′ is formed with longitudinal slit  1213 ′ for handle arm  1212 ′ of handle  1211 ′. Longitudinal slit  1213 ′ has proximal end  1219 ′ and distal end  1220 ′. Locking means or tab  1246 ′ with flexible arm  1229 ′ is fastened via pin  1243 ′ to hollow stem  1203 ′ and has arrest tooth  1245 ″ engaging opening  1242 ′ in hollow stem  1203 ′. Tab  1246 ′ has handle  1208 ′ for manual release of locking tab  1246 ′.  
         [0039]    Stem tip  1201 ′ is of general spheroid, elliptical cross section or ovoid shape. The roundness of the stem tip  1201 ′ confers the important feature of bluntness to stem tip  1201 ′ and, as it will be described below, it will consent to gain access to the chest cavity by dissecting the chest wall by blunt dissection, which is critical in avoiding injuries to the structures of the chest wall and to the intrathoracic organs, such as the heart. Stem tip  1201 ′ has openings  1238 ′ for passage of electrode-ribs  1216 ′.  
         [0040]    Stem end or tip  1201 ′, firmly attached to distal segment  1233 ′ of hollow stem  1203 ′ of stem member  1202 ′ is of greater width than contiguous distal segment  1233 ′.  
         [0041]    Electrode-ribs  1216 ′ are made of resilient material such as steel or suitable medical grade plastic. If made of steel they require insulating coat. Also, fiberoptic cables can run with electrode-ribs  1216 ′ within hollow stem  1203 ′, or alternatively electrode-ribs  1216 ′ can be made of suitably resilient fiberoptic material to provide endoscopic also visualization of the intrathoracic organs such as the heart and the epicardium for confirmation of proper positioning of pads or webs  1222 ′ on the epicardium. All electrode-ribs  1216 ′ are connected at their respective proximal ends  1225 ′ to distal end  1218 ′ of rod  1210 ′, slideable, as already described, within hollow stem  1203 ′ of stem member  1202 ′.  
         [0042]    As best seen in FIGS. 2 and 3, electrode-ribs  1216 ′ are in a set of two pairs and each rib has distal blunt end  1215 ′. Each pair of electrode-ribs  1216 ′ has, in correspondence of their distal segment, web  1222 ′ of grossly triangular shape, made of electrical conductive material. As best seen in FIG. 3, web  1222 ′ has an epicardial contacting and conducting surface  1260 ′ and an electrically insulated opposite surface  1261 ′. Webs  1222 ′ function as electrodes for transmitting electrical current to the heart for defibrillation, cardioversion and pacing, and also function as sensors of cardiac electrical activity and also can function as sensors of epicardial contact pressure.  
         [0043]    An insulated electrically conductive cable  1270 ′ is connected to each web  1222 ′ and is mounted along electrode-ribs  1216 ′ within hollow stem  1203 ′ to exit through opening  1207 ′ formed in hollow stem  1203 ′ to be connected to an external electrical therapy device such as a defibrillator-cardioverter, a cardiac pacing device or to an electrocardiographic monitoring device.  
         [0044]    Prior to use each pair of electrode-ribs  1216 ′ is retained in their entire length within hollow stem  1203 ′ and forced to bunch together very close one to another, against their resiliency which urges them to diverge outwardly one from another in correspondence of their distal segments.  
         [0045]    Description of operation of device of FIGS.  1  to  4 .  
         [0046]    The operator makes a small superficial incision in the patient′s skin on the anterior chest wall preferably in the left parasternal region along the left parasternal border, in a skin area corresponding to the intrathoracic anatomical area designated as “trigonum sine pleura”, i.e. “triangle without pleura”. Usually such area corresponds to the fourth and fifth intercostal space. However anatomical variants are possible where the trigonum sine pleura extends to contiguous intercostal spaces. Access to the chest cavity can also be gained through the subxyphoideal region.  
         [0047]    A skin incision, approximately ⅜″ long or less, is carried out on the very superficial layer of the skin, to a depth comprised ordinarily between {fraction (1/16)}″ to ⅛″ for the purpose of overcoming the resistance of the skin encountered by the blunt tip  1201 ′ of the device in entering the chest wall of a patient. The superficial skin incision is carried out with a suitable surgical instrument such as a lancet or the tip of a surgical knife preferably provided with an arrest to prevent deeper penetration.  
         [0048]    Spheroidally shaped tip  1201 ′ of device  1200 ′ is then inserted by the operator into the skin incision. Operator then carefully gradually advances the device through the chest wall  107  by blunt dissection by holding the device by hand in close proximity of the chest wall  107  and forcing the device downward through the chest wall thickness. By such method the device can only be advanced in steps of predetermined amount equal to the distance between the chest wall and the hand of the operator holding the device in proximity of the chest wall. In such a fashion the device is indeed advanced through the chest wall in a gradual stepwise manner toward the chest cavity. A number of more sophisticated mechanisms of gradual advancement of the blunt stem tip through the chest wall, achieving a high degree of safety and effectiveness, can be used, such as the mechanisms disclosed by Zadini et Al. in their issued Pat. No. 5/466,221, copending patent application Ser. No. 08/100,573 filed on Jul. 30, 1993 allowed and abandoned, copending patent application Ser. No. 08/600,306, a Continuation of patent application Ser. No. 08/100,573, file Feb. 12, 1996, now allowed, and copending patent application Ser. No. 08/555,589 filed on Nov. 13, 1995 and now pending.  
         [0049]    Stem member  1202 ′ is advanced by blunt dissection through the thickness of chest wall  107  until blunt entry of the means which opens the passage through the chest wall, i.e. stem tip  1201 ′, is gained into chest cavity  110 . Being stem tip  1201 ′ of hollow stem  1203 ′ of a greater width than distal contiguous segment  1233 ′ of hollow stem  1203 ′, the stem tip  1201 ′ allows the operator of the device, upon entry of tip  2001 ′ into the chest cavity  110 , to tactually sense entry of the blunt distal stem end  1201 ′ into the chest cavity by the sudden fall of resistance to forward and sideways movement of stem tip  1201 ′, said resistance to forward and sideways movements being present during passage of said stem tip  1201  ′ through chest wall  107 , due to constraint exerted by chest wall tissues upon stem tip  1502  during its passage through chest wall  107 .  
         [0050]    A number of more sophisticated mechanisms for sensing entry of the stem tip into the chest cavity, achieving a high degree of safety and effectiveness can be used, such as the mechanisms disclosed by Zadini et Al. in their issued Pat. No. 5/466,221, in their copending patent application Ser. No. 08/100,573 filed on Jul. 30, 1993 allowed and abandoned, in their copending patent application Ser. No. 08/600,306, a Continuation of patent application Ser. No. 08/100,573, file Feb. 12, 1996, now allowed, and in their copending patent application Ser. No. 08/555,589 filed on Nov. 13, 1995 and now pending.  
         [0051]    When the operator has ascertained penetration of stem tip  1201 ′ of stem member  1202 ′ into chest cavity  110 , she or he advances slideable rod  1210 ′ relatively to hollow stem  1203 ′ by holding still with one hand, hollow stem  1203 ′ by its distal segment, and acting upon handle  1211 ′ with his or her other hand so as to move rod  1210 ′ downwardly, toward chest cavity  110 . The purpose of holding hollow stem  1203 ′ still and firmly by its distal segment is to avoid accidental unduly advancement of the device towards the heart. Rod handle  1211 ′ is then advanced to place webs  1222 ′ on the proper position on the epicardium. Being distal end  1218 ′ of rod  1210 ′ connected to proximal ends  1225 ′ of electrode-ribs  1216 ′, the downward movement of rod  1210 ′ will result with ejection end exit of electrode-ribs  1216 ′ through openings  1238 ′ of stem tip  1201 ′. Rod  1210 ′ is retained in the chosen position by engagement of arrest tooth  1245 ″ of locking tab  1246 ′ on one of notches  1209 ′ of rod  1210 ′. Engaged arrest tooth  1245 ″ of locking tab  1246 ′ will prevent backward and forward displacement of electrode-ribs  1216 ′. Upon ejection of distal segments of ribs  1216 ′ from stem tip  1201 ′, electrode-ribs  1216 ′ as best seen in FIG. 2, will diverge outwardly one from another due, as already described, as a result of their resiliency.  
         [0052]    Webs or pads  1222 ′ of each electrode ribs  1216 ′ pair will unfold and spread between each pair of electrode-ribs to provide an electrode of conductive surface of suitable size in contact with the heart.  
         [0053]    As soon as deployed, webs or pads  1222 ′ are placed in contact with the epicardium by downward resiliency of the ribs and or by the operator pressing downward on handle  1206 ′ of device  1200 ′.  
         [0054]    The distance between pads  1222 ′ on the epicardium can be suitably adjusted by the operator acting upon handle  1211 ′ to advance or withdraw rod  1210 ′ slideable within hollow stem  1203 ′ to the desired position secured by tooth  1245 ″ of tab  1246 ′ which releasably engages notches  1209 ′ of rod  1210 ′.  
         [0055]    The device can also be rotated by the operator around its longitudinal axis in order to position pads  1222 ′ on the desired epicardial areas.  
         [0056]    Insulated electrically conductive cable  1270 ′ are connected for use to a defibrillator, a cardioconverter or a pacer to enable percutaneous epicardial defibrillation, cardioversion or pacing. Sensing of cardiac electrical activity is provided by webs or pads  1222 ′.  
         [0057]    Conductive surface  1260 ′ of web  1222 ′ can be provided with accessories such as miniature or micro needles of conductive material arranged in a brush like fashion capable of penetrating through the epicardial lining into the myocardium to provide a type of myocardial electrode for myocardial defibrillation, cardioversion or pacing.  
         [0058]    At completion of the electrical resuscitative efforts electrode-ribs  1216 ′ are withdrawn by withdrawing handle  1211 ′ of rod  1210 ′, after manual release of locking tab  1246 ′ by action on handle  1208 ′ to disengage tooth  1245 ″ from notches  1209 ′ of rod  1210 ′.  
         [0059]    [0059]FIG. 4 shows an alternative form, generally indicated at  1600 ′, of device  1200 ′ of FIG. 1 through  3 . Structurally, alternative form  1600 ′ differs from device  1200 ′ in having only one pair of electrode-ribs which carries only one epicardial pad/sensor  4000 . The single pad/sensor  4000  is positioned on the epicardium, while another pad/sensor  4002  is positioned on the skin of the back of the patient. Stem tip  1201 ′ has opening  1272 ′ to allow exit of electrode-ribs pair  1216 ′. Access to chest cavity is gained precisely in the same way as with device  1200 ′ of FIGS. 1 through 3. Insulated electrically conductive cable  1270 ′ connected to epicardial pad  4000  as well as insulated electrically conductive cable  1280 ′ connected to external pad  4002  on the skin of the back of the patient, are connected for use to a defibrillator, a cardioconverter or a pacer to enable percutaneous epicardio-to-cutaneous defibrillation, cardioversion or pacing. Sensing of cardiac electrical activity can be provided by pads  4000  and  4002 .  
         [0060]    In FIGS. 5 through 9 is shown an alternative form, generally indicated at  1070 , of device  1200 ′, of FIGS.  1  to  3 , in which the defibrillating, pacing/sensing electrodes are applied to the expandable member of a cardiac resuscitation device for percutaneous direct cardiac massage. Such percutaneous direct cardiac massager is disclosed by Zadini et Al. in their issued Pat. No. 5/466,221, in their copending patent application Ser. No. 008/100,573 filed on Jul. 30, 1993 allowed and abandoned, in their copending patent application Ser. No. 08/600,306, a Continuation of patent application Ser. No. 08/100,573, file Feb. 12, 1996, now allowed, and in their copending patent application Ser. No. 08/555,589 filed on Nov. 13, 1995 and now pending.  
         [0061]    Device  1070 , as shown in FIG. 5, is composed of five main components: a support case or member generally indicated at  1072 , a stem member or unit generally indicated at 1074, an intermediate member generally indicated at 700, an inflating-deflating means or device generally indicated at 1008′ and an epicardial unit for electrical cardiac therapy generally indicated at 2000.  
         [0062]    As best shown in FIG. 5, the support case  1072  is hollow and is of a generally tubular, cylindrical shape having a top wall  1073 , a body  801  and a distal end  5 , including a narrow neck  6  and a flat, circular base  7 . The base  7  is preferably formed of transparent material to enable the operator to better visualize the actual position of the tip  1502  of device  1070  on the anterior chest wall of the patient. Also, base  7  is formed with a central opening  31  to allow passage therethrough of stem  602  of the stem member  1074 , as more fully described below.  
         [0063]    The support case  1072  has a generally hollow cylindrical body  801  encircling the intermediate member  700  and the stem member  1074 .  
         [0064]    As better shown in FIGS. 5 and 6, lever  854  encircles with its expanded head  857  support member  1072  at its midportion and is held in that midportion by the presence of two annular rails  898  and  899 . Lever  854  carries a dog support  858  to which a dog  851  is pivotally secured via a pin  856  and is provided with dog arrest  859  for dog  851 . Dog  851  projects through opening  853  of support member  1072  and reaches for ratcheting engagement teeth  744  of annular rack  742  mounted on the intermediate member  700 .  
         [0065]    As shown in FIG. 5, tab  1080  is mounted on outer surface of support member  1072  and is composed of pin  1082  and flexible arm  1084 . Pin  1082  of tab  1080  is secured to support case  1072  and engages through opening  864  annular recess  865 .  
         [0066]    The intermediate member  700  is interposed between the stem member  1074  and the support case  1072  and is of generally cylindrical shape, with the female threaded portion  641  located approximately midway of the length of support member  1072 , and has an annular rack  742  extending about the exterior of the middle of the intermediate member  700 , provided with a plurality of outwardly projecting teeth  744 .  
         [0067]    Stem member  1074  has a generally hollow cylindrical shape and comprises body  613  and hollow stem  602 .  
         [0068]    Stem member  1074  is closed at its proximal end by top wall  1075 . Body  613  of stem member  1074  is provided with a male threaded portion  603  which mates with the female threaded portion  641  of the intermediate member  700  as described above. Hollow stem  602  communicates with lower end  615  of body  613  and projects through the base  7  of the support case  1072  to communicate with stem tip  1502 .  
         [0069]    Spring or resilient member  280  is located within lower segment of support case  1072 , encircles hollow stem  602  and bears against lower end  615  of support member  1074  to urge stem member  1074  upward.  
         [0070]    Distal end  1012  of hose  1014  of inflating-deflating means  1008  passes through longitudinal slit  1010  of support case  1072  and is connected to stem  602  at window  1016 . Longitudinal slit  1010  formed on wall of support case  1072  permits that insertion of distal end  1012  of hose  1014  into stem  602  is maintained in use upon sliding of stem  602  in respect of support case  1072 . Three ways shut off valve  1018  is located at connection between distal end  1012  of hose  1014  and stem  602 .  
         [0071]    Inflating-deflating means or device  1008  is generally cylindrical in shape with top wall  1022 , bottom wall  1024  and lateral pleated walls  1026 . Resilient member or spring  1028  is contained within device  1008  to maintain lateral wall  1026  distended in its resting position prior to use. It is obvious that manually operated inflating deflating device  1008  may be substituted by a power operated inflating-deflating device.  
         [0072]    As best seen in FIG. 7, stem tip  1502  is composed of two parts: proximal part  1504  shaped as an inverted cup firmly attached to the distal end of stem  602  of stem member  1074 , and distal part or convex apex  1506 . Convex apex  1506  is firmly attached to inner hollow stem  1508  which is telescopically slideable in airtight fashion within hollow stem  602  and has proximal opening  1522  Convex apex has circular edge  1510  adapted to fit together with circular edge  1512  of circular opening  1514  of proximal part  1504  of stem tip  1502  to form together a spheroidally shaped stem tip  1502 . Inner hollow stem  1508  has at least one distal opening  1516  within stem end  1502  in flow communication with expandable member or balloon  1520  which is partially or fully contained in a contracted status within stem end  1502 . Hollow inner stem  1508  also provides lateral stability to expandable member  1520  upon its expansion in operation and also provides the device with means of direction, and allows the operator to have full control on the direction to be given to the expandable member in respect to the position of the heart during compression-decompression.  
         [0073]    As best seen in FIGS. 8 and 9, device  1074  is provided with two electrode-pads or patches  2001  mounted on the heart contacting surface of expandable member  1520 . The two pads  2001  are pliable to allow to be folded within stem end  1502  and/or in distal segment of hollow stem member  1508  together with balloon  1520  and to be deployed upon expansion of balloon  1520 . Each pad  2001  is connected via coiled cable  2002  within stems  1508  and stem  602  to air-sealingly exit through stem  602  and then through the wall of support case  1072  to be connected to an electrical therapy device such as a defibrillator/cardioconverter, to a pacer or to an electrocardiographic monitoring device.  
         [0074]    As best shown in FIG. 5, cables  2002  are conveniently coiled within hollow stem  602  to not oppose, by uncoiling, the sliding, occurring during use, of inner hollow stem  1508  within hollow stem  602 .  
         [0075]    A fiberoptic cable can be inserted into hollow stems  602  and  1508  to reach transparently made convex apex  1506  of stem tip  1502  to provide visualization of chest cavity organ and confirm proper positioning of the device tip  1502 . As connecting cable  2002 , the fiberoptic cable can exit stem  602  in an air sealingly fashion to be connected to an optical monitoring device. The fiberoptic cable can be withdrawn once the proper position of the tip  1502  has been ascertain to allow free passage of air or gas for the inflation-deflation of balloon  1520 . Hollow stem  602 , with its extension  1508 , can also be used as pathway for the administration of medication directly to the heart.  
         [0076]    Description of operation of device of FIGS.  5  to  9 .  
         [0077]    After a small superficial incision is made on the anterior chest wall, which could be as small as one centimeter in length, to allow that blunt end or spheroidally shaped stem tip  1502  wins the skin resistance, in the left parasternal region in a location of the skin corresponding to the intrathoracic anatomical area designated as “trigonum sine pleura”, blunt tip  1502  of the device is engaged into the skin incision and is advanced by blunt dissection through the thickness of the chest wall by the operator.  
         [0078]    The operator ratchets the lever  854  laterally, while keeping the base  7  of the support case  1074  pressing steadily against the patient&#39;s chest. This action causes dog  851  to drive the teeth  744  on rack  742  to rotate the intermediate member  700 . Since the operator is preventing rotation of the stem member  1074 , and since intermediate member  700  is prevented from advancing by pin  1082  projecting through opening  864  and engaging annular recess  865  of intermediate member  700 , the rotation of intermediate member  700  will cause threads  641  to interact with threads  603  of the stem member  1074  to force stem member  1074  to advance stem tip  1502  through the chest wall structure  107  until stem tip  1502  penetrates chest cavity  110 . The gradual and controlled slow advancement of stem  1074  will result in penetration of stem tip  1502  into chest cavity  110 . Once the passage of relatively broad stem end  1502  is completed, and relatively narrow stem  602  is engaged in the chest wall hole formed by stem end  1502 , the operator will immediate tactually sense entry of blunt stem tip  1502  into chest cavity  110  by the sudden fall of resistance to forward and sideways movements, said resistance to forward and sideways movements being present during passage of said stem tip  1502  through chest wall  107 , due to constraint exerted by chest wall tissues upon stem tip  1502  during its passage through chest wall  107 . Blunt stem tip  1502  is therefore advanced through the thickness of chest wall  107  by blunt dissection until it enters the chest cavity by blunt dissection. Upon receipt of this signal, the operator will cease to actuate the lever  854 .  
         [0079]    The choice of the “trigonum sine pleura” prevents the insurgence of pneumothorax, i.e. collapsing of the lungs, which inevitably occurs every time the pleural cavity is entered. With regard to the occurrence of pneumothorax, due to the fact that the “trigonum sine pleura” is a substantially restricted area, the choice of such area is only meaningful if the passage opened through the chest wall is significantly small, as it can be achieved with all the embodiments described in this invention. Being the width of this area invariably small, ordinarily in the range of less than two/two and a half centimeter, it is critical that the heart compressing member which has to be passed through the chest wall to enter the chest cavity is contracted to a comparably small size, i.e. less than the width of the “trigonum sine pleura”.  
         [0080]    As pointed out above, upon entry of blunt stem tip  1502  into the chest cavity, the operator will be alerted of the occurred entry of stem tip  1502 . Balloon  1520  will then be inflated by the operator as follows. The operator will open valve  1018 , then will compress pneumatic source or inflating-deflating device  1008 . Air or suitable gas such as CO2 will flow into hollow inner stem through opening  1522  of inner hollow stem  1508  and will exit through distal opening  1516  located within stem tip  1502  to enter balloon  1520  enabling inflation of balloon or expandable member  1520 . As balloon  1520  begins to inflate, as seen in FIG. 8, hollow inner stem  1508 , being telescopically slideable within hollow stem  602 , will be dragged forward with convex apex  1506  to which is firmly attached, being convex apex  1516  of stem tip  1502  being firmly attached to the heart contacting surface of balloon  1520 .  
         [0081]    [0081]FIG. 9 shows balloon or expandable member or inflatable-deflatable member  1520  inflated to the required pressure to achieve cardiac compression.  
         [0082]    As shown in FIGS. 8 and 9 pads  2001  will contact the epicardium as soon as balloon  1520  begins to inflate. Besides providing guidance to the direction of compression and decompression of the heart, telescopically sliding hollow stems  602  and  1508  provide also guidance for proper placement of pads  2001  on the epicardium. The device at this point can be used by the operator both for direct compression of the heart and for electrical therapy. With this device both operations can be conveniently carried out simultaneously.  
         [0083]    As for device  1600 ′, in an alternative form here not illustrated but easily inferable from device  1070 , device  1070  can be provided with a single epicardial pad while the other pad is positioned externally on the skin of the back of the patient. The epicardial pad can be either attached to the balloon or to stem tip convex apex  1506 .  
         [0084]    [0084]FIGS. 10 and 11 show an alternative form of device  1200 ′ of FIGS. 1 through 4 in which the means for opening a passage via blunt dissection through the chest wall are physically separated from the device component used for electrical therapy.  
         [0085]    The means for opening the passage through the chest wall or chest wall blunt dissector, generally indicated at  4500 , is composed of handle  4502 , stem  4504  and dissecting blunt tip  4506 . Handle  4502  is of generally cylindrical hollow shape having proximal end  4508  and distal end  4510  and is firmly connected by distal end  4510  to hollow stem  4504  of smaller diameter than handle  4502 . Dissecting blunt tip of generally spheroidal shape is firmly attached to distal end  4512  of hollow stem  4504 . Stem tip  4506  can be provided with opening  4514  in communication with the interior of hollow stem  4504  and handle  4502  for passage of electrode-ribs  4520 . Electrode ribs  4520  are in all similar to electrode ribs  1216 ′ of FIGS.  1  to  4  in design and operation.  
         [0086]    In use chest wall blunt dissector  4500  is operated precisely as device  1200 ′ of FIGS.  1  to  4  up to the point when the operator has sensed entry of the blunt tip  4506  into the chest cavity. Upon reaching the chest cavity by blunt dissection with chest wall blunt dissector  4500 , the operator introduces and advances electrode-ribs  4520  into hollow handle  4502  through hollow stem  4504 , through openings  4514  of tip  4506  of chest wall blunt dissector  4500  to properly place pads  4522  of electrode ribs  4520  onto the epicardium ready for use.  
         [0087]    Alternatively chest wall blunt dissector  4500  can be withdrawn from the chest, once it has gained access into the chest cavity by creating a hole through the chest wall, to leave a passage for the subsequent step of introducing electrod-ribs  4520 .  
         [0088]    For this purpose chest wall blunt dissector can be made solid rather than hollow.  
         [0089]    [0089]FIGS. 12 and 13 show an alternative form of the Epicardial Percutaneous Device for Electrical Cardiac Therapy of FIGS. 1 through 4 in combination with an alternative form of the Cardiac Resuscitation Device for Percutaneous Direct Cardiac Massage illustrated in FIGS. 5 through 9. This type of Cardiac Resuscitation Device for Percutaneous Direct Cardiac Massage has been fully disclosed by Zadini et Al. in their issued Pat. No. 5/466,221, in their copending patent application Ser. No. 08/100,573 filed on Jul. 30, 1993 allowed and abandoned, in their copending patent application Ser. No. 08/600,306, a Continuation of patent application Ser. No. 08/100,573, file Feb. 12, 1996, now allowed, and in their copending patent application Ser. No. 08/555,589 filed on Nov. 13, 1995 and now pending. Applicants here disclose the most important features in combination with the Epicardial Percutaneous Device for Electrical Cardiac Therapy. As shown in FIG. 12, which is a cross sectional schematic view of the device, generally indicated at 1, is composed of support case  2 , of generally cylindrical shape, and stem unit  100  coaxially slideable within support case  2 , and electrical unit  110 . Stem unit or member  100  has, proximally, handle  111  for manipulation of the device and, distally, stem  102  with blunt stem tip or end  104 , of general spheroidal shape, which houses, with the device at rest, expandable member or balloon  105 . Within stem unit  100  is contained in its proximal segment pneumatic container  129  for inflation of balloon  105  as it will be explained below. Lever  17  acts upon stem unit  100  to permit gradual controlled advancement of blunt stem tip  104  of stem  102  into the chest cavity through chest wall  107 . The numerous mechanisms of advancement, manual and automatic, as well as other safety features of the Cardiac Resuscitation Device for Percutaneous Direct Cardiac Massage have already been described at length in the above mentioned patents and, although they are important features for the design and operation of the Epicardial Percutaneous Device for Electrical Cardiac Therapy, they have been omitted here because they are not essential for the understanding of the use of the Epicardial Percutaneous Device for Electrical Cardiac Therapy. In use, as for the device  1070  of FIGS. 5 through 9, the operator, after the initial skin incision in the same areas of the anterior chest wall used for all the previously described devices, inserts stem tip or end  104  of device  1  into the incision. He or she then acts upon lever  17  which, as above indicated, advances stem tip  104  through the thickness of the chest wall  107 . Stem tip  104 , during its advancement, creates a passage through the thickness of chest wall  107  via blunt dissection, and enters bluntly and safely due to its blunt features into chest cavity in front of the heart. At this point, as shown in FIG. 12, balloon or expandable member  105  is automatically inflated to a fully inflated status as shown in FIGS. 12 and 13 by pneumatic container  129 . Unlike device  1070  in which cardiac compression is achieved by alternating inflation and deflation of the balloon, in this alternative form the balloon  105  is fully inflated to a predetermined shape and size and maintained in such expanded status in order to provide a sufficiently rigid heart contacting surface for direct cardiac massage. As shown in FIG. 13, the operator by acting upon handle  111  will press stem unit  100  downward causing compression of the heart and, by releasing the downward pressure on handle  111 , will cause decompression and blood refilling of the heart.  
         [0090]    Conductive pliable or foldable or contractible pads  120  of electrical unit  110 , connected to a defibrillator, cardioverter or pacer, or to an electrocardiographic monitoring device via cable  121 , will contact the epicardium when balloon  105  will begin to inflate. The device at this point can be used by the operator both for direct compression of the heart and for electrical therapy. As in device  1070  of FIGS. 5 through 9 both operations can be conveniently carried out simultaneously. As for device  1070  of FIG. 5 through  9 , the device can be provided with fiberoptic means of visualization for ascertaining of proper positioning of the electrical pads on the epicardium.