Abstract:
A pericardiocentesis apparatus and method for accessing the pericardial space. The invention consists of inserting a percutaneous tube whose tip has a hole which is positioned over and contacts the anterior pericardium. Introducing a vacuum within said tube forms a pericardial bleb within that hole. A guided needle within the tube is advanced to puncture the pericardial bleb while avoiding contact with the epicardium. A hollow filament or electrocardial lead or flexible guide wire within said needle can then be advanced into said pericardial cavity. The guide wire may be used to guide a intrapericardial catheter into the pericardial space for injection or infusion of selected therapeutic agents into the pericardial space to treat various heart and blood vessel diseases. Controlled drug release material(s) can be injected through said needle for the slow and/or sustained delivery of said therapeutic agents into said pericardial cavity.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation application of U.S. Ser. No. 9/158,024 filed Sep. 21, 1998, now U.S. Pat. No. 6,162,195, now which is a divisional application of U.S. Ser. No. 08/484,299 filed Jun. 7, 1995, now U.S. Pat. No. 5,827,216, which applications are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to methods and apparatus for accessing the pericardial space for medical treatment of the heart. 
     Knowledge of the pericardium dates back to the time of Galen (129-200 A.D.) the Greek physician and anatomist who gave the pericardium its name. The pericardial sac surrounds the heart like a glove enfolds a hand, and the pericardial space is naturally fluid-filled. The normal pericardium functions to prevent dilatation of the chambers of the heart, lubricates the surfaces of the heart, and maintains the heart in a fixed geometric position. It also provides a barrier to the spread of infection from adjacent structures in the chest, and prevents the adhesion of surrounding tissues to the heart. See generally, Holt J P:  The normal pericardium, Amer J Cardiol  26:455,1970; Spodick D H:  Medical history of the pericardium, Amer J Cardiol  26:447,1970. The normal pericardial space is small in volume and the fluid film within it is too thin to functionally separate the heart from the pericardium. It has been observed that when fluid is injected into the pericardial space it accumulates in the atrioventricular and interventricular grooves, but not over the ventricular surfaces [Shabetai R:  Pericardial and cardiac pressure, Circulation  77.1, 1988]. 
     Pericardiocentesis, or puncture of the pericardium, heretofore has been indicated for (1) diagnosis of pericardial disease(s) by study of the pericardial fluid, (2) withdrawal of pericardial fluid for the treatment of acute cardiac tamponade, and (3) infusion of therapeutic agents for the treatment of malignant effusion or tumors. During 1994, it is estimated that approximately 12,000 pericardiocentesis procedures were performed in the United States and that less than 200 of these patients underwent therapy with the intrapericardial injection of drugs. At present, intrapericardial injection of drugs is clinically limited to the treatment of abnormal pericardial conditions and diseases, such as malignant or loculated pericardial effusions and tumors. Drugs that have been injected into the pericardial space include antibiotic (sclerosing) agents [Wei J, et al:  Recurrent cardiac tamponade and large pericardial effusions: Management with an indwelling pericardial catheter, Amer J Cardiol  42:281,1978; Davis S, et al:  Intrapericardial tetracycline for the management of cardiac tamponade secondary to malignant pericardial effusion, N Engl J Med  299:1113,1978; Shepherd F, et al:  Tetracycline sclerosis in the management of malignant pericardial effusion, J Clin Oncol  3:1678,1985; Maher E, et al:  Intraperi-cardial instillation of bleomycin in malignant pericardial effusion, Amer Heart J  11:613,1986; van der Gaast A, et al:  Intrapericardial instillation of bleomycin in management of malignant pericardial effusion, Eur J Cancer Clin Oncol  25:1505,1989; Imamura T, et al:  Intrapericardial instillation of OK -432  for the management of malignant pericardial effusion, Jpn J Med  28:62,1989, Cormican M, et al:  Intraperi-cardial bleomycin for the management of cardiac tamponade secondary to malignant pericardial effusion, Brit Heart J  63:61,1990; Mitchell M, et al:  Multiple myeloma complicated by restrictive cardiomyopathy and cardiac tamponade , Chest 103:946, 1993], antineoplastic drugs [Terpenning M, et al:  Intrapericardial nitrogen mustard with catheter drainage for the treatment of malignant effusions, Proc Amer Assoc Cancer Res  (abstr) 20:286,1979; Markman M, et al:  Intrapericardial instillation of cisplatin in a patient with a large malignant effusion, Cancer Drug Delivery  1:49,1985; Figoli F, et al:  Pharmacokinetics of VM  26  given intrapericardially or intravenously in patients with malignant pericardial effusion, Cancer Chemotherapy Pharmacol  20:239, 1987; Fiorentino M, et al:  Intrapericardial instillation of platin in malignant peri - cardial effusion, Cancer  62:1904,1988], radioactive compound [Martini N, et al:  Intra-pericardial instillation of radioactive chronic phosphate in malignant pericardial effusion, AJR  128:639,1977], and a fibrinolytic agent [Cross J, et al:  Use of streptokinase to aid in drainage of postoperative pericardial effusion, Brit Heart J  62:217,1989]. 
     Intrapericardial drug delivery has not been clinically utilized for heart-specific treatments where pericardial pathology is normal, because the pericardial space is normally small and very difficult to access without invasive surgery or risk of cardiac injury by standard needle pericardiocentesis techniques. The pericardiocentesis procedure is carried out by experienced personnel in the cardiac catheterization laboratory, with equipment for fluoroscopy and monitoring of the electrocardiogram. Electrocardiographic monitoring of the procedure using the pericardial needle as an electrode is commonly employed [Bishop L H, et al.  The electrocardiogram as a safeguard in pericardiocentesis , JAMA 162:264,1956; Neill J R, et al:  A pericardiocentesis electrode, N Engl J Med  264:711,1961; Gotsman MS, et al:  A pericardiocentesis electrode needle, Br Heart J  28:566,1966; Kerber R E, et al:  Electrocardiographic indications of atrial puncture during pericardiocentesis, NEngl JMed  282:1142,1970]. An echocardiographic transducer with a central lumen has also been used to guide the pericardiocentesis needle [Goldberg B B, et al:  Ultrasonically guided pericardiocentesis, Amer J Cardiol  31:490,1973]. Complications associated with needle pericardiocentesis include laceration of a coronary artery or the right ventricle, perforation of the right atrium or ventricle, puncture of the stomach or colon, pneumothorax, arrhythmia, tamponade, hypotension, ventricular fibrillation, and death. The complication rates for needle pericardiocentesis are increased in situations where the pericardial space and fluid effusion volume is small (i.e., the pericardial size is more like normal). 
     Chin et al have described a method and apparatus for accessing the pericardial space for the insertion of implantable defibrillation leads [US. Pat. No. 5,071,428]. The method required gripping the pericardium with a forceps device and cutting the pericardium with a scalpel (pericardiotomy) under direct vision through a subxiphoid surgical incision. 
     A method for the intrapericardial injection of angiogenic agents has been reported [Uchida Y, et al:  Angiogenic therapy of acute myocardial infarction by intrapericardial injection of basic fibroblast growth factor and heparan sulfate, Circulation AHA Abstracts— 1994]. While the method was not described in detail, it generally involved the percutaneous transcatheter bolus injection of drugs into the pericardial cavity via the right atrium. The major limitation of this method is that the right atrial wall is crossed which could lead to bleeding into the pericardial space. In addition, the method involved the bolus injection of drugs rather than long-term delivery via a catheter or controlled release material. 
     SUMMARY OF THE INVENTION 
     A principal object of the invention is to provide a method and apparatus for accessing the pericardial space without invasive surgery and to reduce the risk of injury to the heart during pericardial catheterization. 
     A more specific object of the invention is to provide an apparatus with the means to create a needle puncture through the wall of the pericardium without puncture of the heart. 
     A further object of the invention is to provide an apparatus with a lumen to be used for the introduction of other elements and materials into the pericardium for site-specific drug delivery to the heart and coronary arteries, or the introduction of implantable defibrillator or other cardioregulatory electrodes into the pericardial space. 
     Still another object of the invention is to provide a method for advancing a catheter into the pericardial space for the withdrawal of pericardial fluid and/or the intrapericardial injection or infusion of bioactive therapeutic agents to treat diseases of the heart and coronary arteries. 
     Yet another object of the invention is to provide an apparatus having a simple mode of operation which may be used to pass a guide wire and catheter into the pericardial space without the need for invasive surgery. 
     The present invention provides apparatus and method for nonsurgical access to the pericardial space through a needle puncture of the anterior pericardium (pericardiocentesis) in a manner reducing risk of injury to the heart, provides a lumen for introduction of substances into the pericardial space through the pierced pericardium, and allows introduction of a catheter into the pericardial space so accessed, thereby to enable the withdrawal of pericardial fluid and/or the intrapericardial injection or infusion of bioactive therapeutic agents to treat diseases of the heart and coronary arteries in a site specific manner, or to allow the introduction of implantable defibrillator electrodes into the pericardial space. 
     An apparatus of the present invention for percutaneously accessing the intrapericardial space comprises an elongated outer tubular body having a closed distal end, an aperture in a sidewall adjacent the closed end, and a proximal portion for applying a vacuum thereto. An elongated inner tubular body has a distal end sealingly extending into the outer tubular body from a proximal end external to the outer tubular body, creating a first passage between the first and inner tubular bodies. A piercing body is disposed in a distal portion of the outer tubular body adjacent the aperture. The piercing body has a sharp distal end and a lumen extending through it from a proximal end of it to a sidewall opening in it adjacent such sharp distal end. The proximal end of the piercing body is connected to the distal end of the inner tubular body, thereby creating a conduit leading from outside the outer tubular body to the piercing body sidewall opening. The piercing body is longitudinally moveable in the outer tubular body to an extent permitting the distal end of the piercing body to traverse the aperture of the outer tubular body and appose the sidewall opening of the piercing body and the aperture of the outer tubular body. Means providing a passage are laterally adjacent the piercing body for permitting flow communication from the aperture of the outer tubular body to the passage between the tubular bodies, under influence of an applied vacuum, regardless of the longitudinal location of the piercing body in the distal portion of the outer tubular body. 
     The invention further constitutes a method for accessing a pericardial space, which comprises percutaneously inserting the distal portion of an elongated outer tubular body containing an aperture in a sidewall adjacent the distal end, locating such distal portion over the pericardium substantially parallel thereto with the aperture facing the pericardium surface, applying a vacuum to the tubular body remotely from the distal portion to draw a portion of the pericardium away from the surface of the heart into the aperture in a capture position, advancing a piercing element contained in the tubular body adjacent the aperture in a direction substantially parallel to the heart to pierce the portion of the pericardium captured in the opening, and retracting the piercing element to leave a hole in the pericardium. 
     The method of this invention further includes delivering a substance through the tubular body and into the pericardial space through the hole created in the pericardium. The substance suitably may be formed or formless. Suitably a formed substance is the distal portion of a filament. The filament may be electro- or photo-conductive, for example, a defibrillator electrode; it may be solid, such as a guidewire; or it may be hollow, such as a catheter. Alternatively the substance may be formless, such as a liquid, paste or gel, and may be bioactive as a cardiovascular drug. 
     Where the substance is a filament, the method further comprises withdrawing the tubular body and the piercing body over the filament, leaving the filament distal portion in place in the pericardial space with a proximal portion inclusive of the proximal end of the filament remaining external to the body of the patient. Where the filament is electro- or photo-conductive, the invention further comprises accessing the proximal portion of the filament to regulate the heart. Where the filament is hollow, this method thereby provides an indwelling catheter to the pericardial space. 
     This invention suitably employs an elongated inner tubular body having a distal end sealingly extending into the percutaneously inserted outer tubular body from a proximal end external to the outer tubular body. The piercing element suitably comprises a body having a sharp distal end and a lumen extending therethrough from a proximal end thereof to a sidewall opening therein adjacent such sharp distal end, the proximal end of the piercing body being connected to the distal end of the inner tubular body, thereby creating a conduit leading from externally of the outer tubular body to the piercing body sidewall opening, the piercing body being longitudinally moveable in the outer tubular body to an extent permitting the distal end thereof to traverse the aperture and appose the piercing body sidewall opening and the aperture. In this embodiment, the substance is delivered through the so provided conduit into the pericardial space through the hole created in the pericardium. 
     In this latter aspect, where the substance is the distal portion of a filament, the step of delivering comprises advancing a filament distal portion through the inner tubular body and through the pericardium portal into the pericardial space. Where the filament is a guidewire, the method of this invention further comprises withdrawing the first and inner tubular bodies and the piercing body over the guidewire, leaving the distal portion of said guidewire in place in the pericardial space, advancing the leading end of a catheter over said guidewire into said pericardial space, and then withdrawing said guidewire to leave said catheter end in said pericardial space. A bioactive substance may then be delivered into the pericardial space through this catheter. 
     Preferably the distal end of the tubular body is radio-opaque. Suitably the apparatus further comprises an electroconductive terminal adjacent said aperture and a terminal lead electroconductively communicating said terminal exteriorly of outer tubular body remotely from said distal end of said outer tubular body. 
    
    
     The nature, objects, and advantages of the present invention will become more apparent to those skilled in the art when viewed in light of the following detailed description and accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a longitudinal, centerline sectional, side-graphical outline or schematic view of the invention illustrating a preferred embodiment of the pericardiocentesis apparatus for nonsurgical intrapericardial access. 
     FIG. 2 is a side schematic view of the distal end portion of the invention. 
     FIG. 3 is a bottom schematic view of the distal end portion of the invention. 
     FIG. 4 is a longitudinal, centerline sectional, side schematic view of the distal end of the invention. 
     FIG. 5 is a longitudinal, centerline sectional, side schematic view of the distal end of the invention showing the needle in the fully retracted (sheathed) position. 
     FIG. 6 is cross sectional view of FIG. 5, taken along the line  6 — 6  of FIG.  5 . 
     FIG. 7 is a longitudinal, centerline sectional, side schematic of the distal end of the invention showing the needle in the fully advanced (extended) position. 
     FIGS. 8 to  12  are longitudinal, centerline sectional, side schematic view of the distal end of the invention and the pericardium, sequentially illustrating the steps of practicing the present invention to first capture the pericardium, then puncture it with a needle (pericardiocentesis), and then insert a intrapericardial guide wire. 
     FIG. 8 is a longitudinal, centerline sectional, side schematic view of the distal end of the invention illustrating its position over the anterior surface of the pericardium. 
     FIG. 9 is a longitudinal, centerline sectional, side schematic view of the distal end of the invention illustrating capture of the pericardium with suction and formation of the pericardial bleb. 
     FIG. 10 is a longitudinal, centerline sectional, side schematic view of the distal end of the invention illustrating the needle in the fully advanced (extended) position with puncture of the pericardial bleb. 
     FIG. 11 is a longitudinal, centerline sectional, side schematic view of the distal end of the invention illustrating insertion of the guide wire through the needle into the pericardial space. 
     FIG. 12 is a side schematic view of the pericardium after removal of the invention illustrating the intrapericardial guide wire. 
     FIG. 13 is a side schematic view of the distal portion of the invention illustrating an embodiment of the intrapericardial access apparatus with a modified distal head. 
     FIG. 14 is a front schematic view of the distal portion of the invention illustrating an embodiment of the intrapericardial access apparatus with a modified distal head. 
     FIG. 15 is a side view of the distal portion of the invention illustrating an embodiment of the intrapericardial access apparatus with an electrode modification. 
     FIG. 16 is a bottom-view of the distal portion of the invention illustrating an embodiment of the intrapericardial access apparatus with an electrode modification. 
     FIG. 17 is an illustration of the heart illustrating the placement of the pericardial access apparatus of the invention inserted subxiphoidally. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 1, an introducer apparatus  100  for percutaneously accessing the intrapericardial space and constructed in accordance with this invention, comprises a distal end portion  102  which is attached to and may be considered a distal extension of first elongate outer tubular body  104  which in turn is attached to a connector portion  106 , which may be considered a proximal extension of tubular body  104 . Connector portion  106  has a side branch  108  which in turn is connected to a vacuum supply  116 . A second or inner elongate tubular body  112  having a distal end  111  and a proximal end  113  extends into first or outer tubular body  104  including connector portion  106  from outside outer tubular body  104 , creating a passage  120  between first and inner tubular bodies  104  and  112 . Passage  120  is an annulus where first and inner tubular bodies  104  and  112  are circular in cross section. At the end of connector  106  is a seal or gasket  110  which seals passage  120  inside of the tubular body  104  and connector portion  106  from ambient pressure while still permitting inner tubular body  112  to move in and out of connector portion  106 . Loaded within tubular body  112  is a guide wire  114 . 
     The distal end portion  102  is illustrated in FIG. 2 with a close-up side-view. The bottom-view of FIG. 2 is illustrated in FIG. 3. A centerline sectional side-view of FIG. 2 is illustrated in FIG.  4 . The distal end portion  102  of introducer apparatus  100  is radio-opaque, rigid, and contains an axial passage  120  which is part of a continuous passage  120  in segments  106  and  108  of outer body  104 . The passage  120  in distal portion  102  terminates axially at a closure or end portion  121 . A radial bore  122  in tubular body sidewall  119  adjacent closure end  121  intersects, suitably orthogonally, passage  120  and creates a cavity at  122  entered by aperture  123 . A needle carrier block  126  is arranged and moveable longitudinally in passage  120  without occluding flow communication of fluid from aperture  123  toward branch  108  under influence of vacuum source  116 . A needle  124  having an axial lumen  125  is carried in needle carrier  126  and attached to the needle carrier using a set screw  128 . Needle  124  has a sharp leading or distal end  127  extending distally from carrier  126  and a trailing or proximal end  129  extending proximately from carrier  126 . Needle  124  includes a sidewall lateral opening  131  adjacent sharp leading end  127  and positioned to be apposed to or alignedly juxtaposed over aperture  123  of radial bore  122  in passage  120  when needle carrier  126  is advanced in tubular body distal portion  102 . At sidewall opening  131 , lumen  125  accesses cavity  122  where piercing of pericardium  144  occurs. Distal end  111  of the second or inner tubular body  112  is axially connected to the trailing end  129  of needle  124 , as shown in FIG.  2 . This connection creates a conduit leading from externally of outer tubular body  104  through inner tubular body  112  and axial lumen  125  to needle sidewall opening  131 . This enables access to the pericardial space through sidewall opening  131  after pericardium  144  is pierced. In FIGS. 1-11 this conduit is occupied by guidewire  114 . The purpose of lumen  125  and the conduit leading through inner tube  112  is not to supply a vacuum to withdraw fluid. That is the purpose of passage  120 , and passage  120  is much larger in cross section than lumen  125 . Suitably the ratio of cross sectional areas of passage  120  to lumen  125  exceeds about  5  and may be up to about  200 , more preferably from about  5  to about  100 , the larger the number, the greater the vacuum force available. However, the vacuum force applied need be only sufficient to acquire and draw a bleb of pericardium into cavity  122  for piercing so that whatever is to be introduced through needle  124  can be delivered into the pericardial space so accessed. 
     FIG. 5 is identical to FIG. 4 except that the needle carrier  126  and retaining screw  132  are not sectioned. Needle carrier  126 , aside from providing a mechanism to mount needle  124  in proper alignment to a platform, also moves between two travel limiters arranged in tubular body distal portion  102  proximately of aperture  123  for limiting longitudinal movement of needle carrier  126  and hence needle  124  in tubular body distal portion  102  toward and away from closed distal end  121 . Carrier  126  includes along an outer surface a longitudinal recess or groove  134  having a blind distal end  138  and an open proximal end  139 . An interior protrusion such as a set screw  132  is mounted on tubular body  102  and extends transversely radially inward, as illustrated in FIG. 6, to protrude into groove  134 . At the fully retracted or proximal position of needle holder  126 , set screw  132  contacts the blind end  138  of groove  134 . Another limiter comprises a constriction  140  at stop  136  in tubular body distal portion  102  distal to and narrower than needle carrier  126  that prevents further distal movement of needle holder  126  past the proximal portion of constriction  140  at stop  136 , as shown in FIG. 7, fixing the fully extended or distal position of needle holder  126  in tubular body  102 . As illustrated in FIGS. 5 and 7 the tip of needle  124  in the fully retracted position (FIG. 5) is limited by protrusion  132  and does not violate the boundary of bore  122 . In the fully extended position (FIG. 7) limited by constriction  140  at stop  136 , needle  124  extends significantly into bore  122 . 
     Instead of this arrangement to control travel, both ends of groove  134  can be blind, with travel being limited by the stop; or a constriction can be furnished both distally and proximally of carrier  126 . Indeed, the travel limiter for the fully extended position of needle  124  and needle carrier  126  suitably is provided by end closure  121  of distal portion  102  of outer tube  104 . However, the embodiment illustrated is of simple construction and is satisfactory. 
     FIG. 6 is section  6 — 6  of FIG.  5 . As seen in FIG. 6, needle carrier  126  is relieved in an upper of its body, providing a passage  130  laterally adjacent carrier  126  permitting flow communication from aperture  123  to the portion of passage  120  proximal of carrier  126 , regardless of the longitudinal location of needle carrier  126  in the distal portion of outer tubular body  102 . Subambient pressure provided by vacuum source  116  results in ambient gas flow from aperture  123  of the tubular body distal portion  102 , through passage  120 , around needle carrier  126  at passage  130 , inside the annulus portion of passage  120  to side branch  108 , to the vacuum source  116 . Instead of relief of the outside periphery of carrier  126 , other means of passage of fluid flow past carrier  126  may be employed, including longitudinal grooves along the periphery of carrier body  126  or separate channels external to the inner periphery of tubular body  104  accessed through openings into the passage  120  located beyond the limit of travel of carrier  126 . 
     Second or inner tubular body  112 , containing the guide wire  114 , is sealed from subambient pressure via seal  110  on connector  106 . 
     FIGS. 8 to  10  more particularly illustrate sequentially the inventive method for puncture of the pericardial wall. At the start of the procedure, a small subxiphoid incision is made in the skin. The method of the present invention for pericardiocentesis is then carried out through the following steps. 
     The tubular body device  104 , with radio-opaque distal end  121 , is inserted through the subxiphoid incision and advanced percutaneously, with the aid of fluoroscopy, over the diaphragm into the mediastinal space and is positioned so that the aperture  123  on the tubular body distal end  102  is over the anterior surface of the pericardial sac  144  (FIG.  8 ). Also shown in section is the wall of the ventricle  146  and the intrapericardial space  148 . 
     Vacuum supply  116 , connected to the branch portion  108  of outer tubular body  104 , is then energized and air is evacuated from the distal portion  102  of tubular body  104  and the side opening  122  which is in contact with the pericardium  144 . Once captured by suction, the pericardial sac  144  stretches to form a “bleb”  150  through aperture  123  into side opening  122  (FIG.  9 ). 
     After pericardial bleb  150  forms, as shown in FIG. 10, the operator may then advance needle  124 , which is sheathed inside distal end  102  of outer tubular body  104  and aligned by movable needle holder  126 . This is done by advancing inner tubular body  112  (FIG. 1) until needle holder  126  encounters stop  136 . This forward movement causes needle  124  to sequentially prick and then puncture the pericardial bleb  150 . The bleb  150  is pierced by needle  124  without contact or injury to the heart  146  since bleb  150  and needle  124  are isolated within cavity  122 . 
     At this point the needle can be withdrawn to leave a hole in the pericardium for access in any of the ways generally described above. FIGS. 11-12 illustrate the aspect of the invention in which a guidewire is introduced into the pericardial space through the hole that was created in the pericardium. 
     After the hole is created in the pericardium, and with needle  124  in the fully advanced position at stop  136 , the vacuum system is deactivated and a flexible guide wire  114  preloaded in needle  124  is then pushed through needle  124  into the pericardial space  148  between the heart  146  and pericardium  144  (FIG.  11 ). The needle is then retracted and the apparatus  100  is percutaneously removed from the patient leaving guide wire  114  in intrapericardial space  148  as illustrated in FIG.  12 . Guide wire  114  facilitates access to the interior of the pericardium. 
     Referring now to FIG. 17, there is illustrated a human heart  200  and ventricle  146  showing the epicardial coronary arteries  202 , the pericardial sac  144  enveloping heart  200 , and pericardial space  148  containing pericardial fluid  206  bathing (exaggerated for purposes of illustration) heart  200  within pericardial sac  144 . One of the coronary arteries  202  is indicated to be stenosed at  203 . Below heart  200  is the diaphragm musculature  208 . In the chest of the patient in front of heart  200  is the sternum  210  and the lower extension thereof called the xiphoid process  211 . Shown percutaneously inserted below xiphoid process  211  is introducer  100  of this invention which has been advanced to a position over pericardium  144  with stabilizer portion  160  maintaining distal potion  102  of outer tube  104  substantially parallel to pericardium  204 , assuring that aperture  123  and radial cavity  122  (not visible, but see FIGS. 8-11) are substantially normal to the pericardium for lifting a portion or bleb  150  of pericardium  144  into cavity  123  for needle piercing and hole creation substantially parallel to the heart to avoid risk of puncture of the heart. In FIG. 17, guidewire  114  has been advanced through the hole created in the pericardium. 
     After guidewire  114  has been advanced into the pericardial space, a catheter may then be percutaneously advanced over guide wire  114  into the pericardial space for the withdrawal of fluid, and/or the intrapericardial injection or infusion of therapeutic agents, or the intrapericardial insertion of implantable materials. 
     As mentioned before, the invention involves only in part the ability to introduce a guidewire and thereby a catheter into the pericardial space. The facility of the conduit provided by lumen  125  in flow communication with the lumen of inner tubular body  112  exiting outside outer tubular body  104  at its proximal end  111  at segment  106  gives a channel for fluids, pastes, gels, particles and solids passage directly to the pericardial space for administration of fluid or implant therapeutic agents to the heart or for implantation of electro- or photo-conductive cardioregulatory apparatus, suitably filamentary devices such as defibrillator electrodes, which, after withdrawal of apparatus  100 , can be accessed outside the patients body and connected to body exterior devices for regulation or monitoring of the heart. Apparatus  100  may be supplied for use with this device channel empty, and when access is gained to pericardial space  146  as has been described, the agents to be delivered to the pericardial space can be pumped, injected or infused directly through this access channel to exit needle side opening  131  (still within pericardial space  146 ) and enter the pericardial space. Alternatively, apparatus  100  can be furnished preloaded with a filament in needle  125  which can be advanced into the pericardial space after it is accessed with apparatus  100 . The filament may itself be hollow and serve as a catheter for in-dwelling administration of therapeutic agents after removal of apparatus  100 . The filament can be solid, as in the instance of a guidewire or electro- or photo-conductive cardioregulation lead. 
     The present application is assigned to the assignee of U.S. patent application Ser. No. 08/264,458 filed Jun. 23, 1994, incorporated herein by reference, which describes a method of treating the coronary arteries of the heart that comprises application of therapeutic substances to the exterior surface of the heart. As already mentioned, fluid injected into the pericardial space accumulates in the atrioventricular and interventricular grooves. Since the epicardial coronary arteries are located in the grooves of the heart, a bioactive therapeutic substance delivered into the pericardial space through the methodology and device of this invention can accumulate and be concentrated over the coronary blood vessels. Intrapericardial drug delivery applications include injection/infusion of liquid drug preparations via a catheter placed according to this invention (“free drugs”), and delivery of constrained release materials for controlled drug release and time-based (long term) pharmacologic therapy, using the method and apparatus of this invention. Such constrained release materials suitably include implants and may comprise biopolymers, biodegradable fibers, liposomes, biodegradable polymeric microspheres, pastes, and gels. Thus this invention provides methods and means for accessing the pericardial space and delivery of a biodegradable drug loaded fiber which releases drug into the pericardial fluid for extended periods of time, for delivery of drug loaded liposomes or drug release microspheres (biodegradable polymer) to accumulate in the ventricular grooves and provide localized drug delivery to the coronary arteries, and for delivery of a drug loaded fibrin biopolymer or drug release gel which can be squeezed into the ventricular sulcus sites providing coronary artery site specific drug delivery. Depending on the viscosity of the substances used, regional site-specific treatment to a particular portion of the coronary circulation can be achieved by injecting the drug delivery material into the pericardium at a particular location using the apparatus of this invention. 
     Cardiovascular drugs for intrapericardial delivery can include vasodilator, antiplatelet, anticoagulant, thrombolytic, anti-inflammatory, antiarrhythmic, inotropic, antimitotic, angiogenic, antiatherogenic and gene therapy agents. Reference is made to co-pending U.S. patent application Ser. No. 08/264,458 filed Jun. 23, 1994 for a description of the methodology of treatment of cardiovascular disease by drugs placed in the pericardial space. 
     FIG. 13 illustrates an embodiment of the present invention in which distal end  121  of the outer tubular body  104  comprises a stabilizer portion  160 . FIG. 14 is a front view of FIG.  13 . Stabilizer portion  160  is axially fixed to distal portion  102  of body  104 , and is frontally ramped in a gently upward slope as indicated by  164 , and narrows vertically from bottom to top as seen in FIG.  14 . This frontal sloping eases entry under the sternum during insertion of the tubular body  104 . Longitudinal grooves  162  along the upper surface of nose  160  help strip or otherwise remove fatty tissue on the pericardial surface away from the device, as well as provide a means of orienting the apparatus  100  to the surface of the pericardium. FIG. 14 indicates two downwardly shaped longitudinal nodes  166  which create a longitudinal concavity  168  between them. This concavity keeps the pericardium from bunching as the device is moved over it. 
     FIG. 15 illustrates an embodiment of the present invention which includes an electroconductive terminal adjacent aperture  123  of outer tubular body distal portion  102  and a terminal lead electroconductively communicating exteriorly outer tubular body remote from distal portion  102 . FIG. 16 is a bottom view of FIG. 15. A ring  170 , which is electrically conductive around side opening entrance  123 , communicates to an electrically conductive strip  172  which is a part of tubular body  102 . FIG. 15 indicates part of the tubular body  104 , cut away to show the addition of a wire  174  or equivalent which is attached to the electrically conductive material  172 . The purpose of this device enhancement is to measure the electrocardiogram (EKG) signal from the heart  146  and pericardium  144 , and transmit this signal back to the proximal end of the invention  100  where it is coupled to a EKG display monitor. Coupling of the invention  100  to a EKG monitor adds further information that the device is contacting the pericardium  144 . Thus this invention further comprising monitoring the electrocardial signal of the heart to determine contact of aperture  123  of tubular body with the pericardium during said percutaneous insertion step. 
     The vacuum in tubular body  104  may also be monitored to detect a decrease in vacuum pressure marking capture of a bleb portion  150  of pericardium in aperture  123  and lateral opening  122 . 
     From the foregoing detailed description, it is believed apparent that the present invention provides a method and apparatus for accessing the pericardial space by needle puncture (pericardiocentesis) without the need for invasive surgery and with a reduced risk of injury to the heart. It should be understood that the invention is not intended to be limited to the specifics of the described preferred embodiments, but is defined by the accompanying claims.