Patent Publication Number: US-2007100409-A1

Title: Method for accessing the coronary microcirculation and pericardial space

Description:
RELATED APPLICATIONS  
      The present application is a division of co-pending U.S. utility patent application Ser. No. 10/497,763, entitled METHOD AND APPARATUS FOR ANCHORING OF PACING LEADS, which is a U.S. national stage application filed under 35 U.S.C. § 371 based on PCT Application No. PCT/US03/37045, entitled METHOD AND APPARATUS FOR ANCHORING OF PACING LEADS, filed Nov. 17, 2003, which in turn claims priority pursuant to 35 U.S.C. § 119(e) to U.S. Provisional Patent Applications Ser. No. 60/426,773, filed on Nov. 15, 2002; Ser. No. 60/476,487, filed on Jun. 6, 2003; Ser. No. 60/479,399, filed on Jun. 18, 2003; and Ser. No. 60/464,437, filed on Apr. 22, 2003. All of the referenced related applications are hereby fully incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The invention relates to the field of cardiology and in particular to apparatus and methods for pacemaker implantations.  
      2. Description of the Prior Art  
      In many cases pacemaker introducers are precurved for steerability and use in the coronary sinus. Being precurved, such introducers cannot be rotated for the purpose of setting a screw-in anchor into myocardium, since their distal ends wobble uncontrollably while being rotated. It is nevertheless advantageous to anchor an introducer when similarly implanting or anchoring the much more flexible pacemaker lead. If the pacemaker lead is not supported by a fixed-in-place introducer, the pacemaker lead itself can either push back and displace the introducer with the result that the pacemaker lead is implanted in the wrong place, or the pacemaker lead simply “spaghettis” or unpredictably folds on itself rather than being controllably driven in or implanted into the myocardial position selected by the surgeon.  
      Pacing of the left ventricle  14  diagrammatically shown in  FIG. 1  is conventionally performed by placement or implantation of a wire or lead  10  in the coronary venous system  12  as diagrammatically shown in the cutaway view of the coronary vein  16  in  FIG. 2 . However, not every location of the wall of the left ventricle  14 , which needs to be paced, is accessible to a lead through the coronary venous system  12  as can be readily appreciated by the vascular anatomy depicted of the coronary venous system  12  and coronary arterial system  18  depicted in the simplified perspective view of  FIG. 2 .  
     BRIEF SUMMARY OF THE INVENTION  
      The invention is an introducer having a distal end comprising an anchor provided on the distal end of the introducer for attachment of the distal end of the introducer into tissue. The anchor attaches at or near the surface of a body cavity, for example in the vascular space, or more particularly in the cardial space. When the introducer is anchored in the cardial space a pacemaker lead is guided through the introducer and anchored therein while the introducer is anchored within cardial space.  
      The invention is directed to anchoring introducers and leads throughout the vascular space, including anchoring into anyone of the walls of the heart chambers, into any vascular location, and into body cavities, usually closely related to the vascular system such as the pericardial space. The anchoring can be realized through a plurality of different means such as screw anchors, barbed anchors, piercing tools with barbs or distal inflatable balloons, grabbing tools or suction anchors.  
      In one embodiment the invention is defined as a method of implanting a pacemaker lead into the pericardial space or microvasculature of a heart comprising the steps of: disposing an elongate instrument into the venous system of the heart; exiting the venous system; disposing the elongate instrument or a different elongate instrument into the pericardial space or microvasculature at a predetermined location; and implanting a pacemaker lead at the predetermined position.  
      The step of implanting a pacemaker lead at the predetermined position comprises the step of implanting the lead in a position adjacent to, on or in the surface of the left ventricle.  
      Preferably, the step of implanting a pacemaker lead at the predetermined position comprises the step of implanting the lead in a position of optimized pacing efficacy.  
      In one embodiment the step of disposing an elongate instrument or a different elongate instrument into the pericardial space or microvasculature at a predetermined location comprises the step of disposing the elongate instrument or a different elongate instrument through the microvasculature into the pericardial space.  
      In another embodiment the step of disposing an elongate instrument or a different elongate instrument into the pericardial space or microvasculature comprises the step of disposing the elongate instrument or a different elongate instrument into a first venous bed.  
      In another embodiment the step of disposing an elongate instrument or a different elongate instrument into the pericardial space or microvasculature comprises the step of disposing the elongate instrument or a different elongate instrument into the vascular mesh.  
      In still another embodiment the step of disposing an elongate instrument or a different elongate instrument into the pericardial space or microvasculature comprises the step disposing the elongate instrument or a different elongate instrument from the first venous bed, through the vascular mesh into a second venous bed.  
      The method further comprises the step of anchoring the implanted pacemaker lead in the pericardial space or microvasculature.  
      In one embodiment the step of implanting the pacemaker lead comprises implanting the pacemaker lead in the microvasculature and further comprises the step of dilating the microvasculature prior to implanting the pacemaker lead therein.  
      In another embodiment the step of exiting the venous system comprises the step of puncturing a vein in the venous system.  
      In still another embodiment the step of exiting the venous system comprises the step of entering the vasculature communicated with the venous system.  
      In yet another embodiment the step of exiting the venous system comprises the step of exiting the vasculature and entering the pericardial space.  
      The step of disposing the elongate instrument or a different elongate instrument into the pericardial space or microvasculature at a predetermined location comprises the step of disposing an introducer, catheter, guidewire, balloon, dilator, needle and/or lead.  
      The invention is also defined as apparatus or a surgical kit of instruments for performing each of the foregoing steps separately or in any combination.  
      The invention is still further defined as an apparatus for implanting a pacemaker lead into heart tissue comprising an inner introducer which is steered into the heart; a first anchor provided on a distal end of the introducer; a pacemaker lead telescopically disposed through the inner introducer; and a second anchor provided on a distal end of the pacemaker lead.  
      The first anchor has an inner diameter large enough to permit telescopic disposition therethrough of the second anchor and pacemaker lead.  
      The apparatus may in some embodiments further comprise an outer biased introducer through which the inner introducer is telescopically disposed and steered to an implantation site.  
      In one embodiment the pacemaker lead is rotatable within the inner introducer and where the second anchor screws into the heart tissue at an implantation site and wherein the first anchor maintains the inner introducer in position while the second anchor screws into the heart tissue at the implantation site. The first anchor can be disengaged from the heart tissue at the implantation site, after the second anchor is implanted without dislodgement of the second anchor and pacemaker lead.  
      In a first embodiment the first anchor is a screw anchor with a first sense of screw advancement and where the second anchor is a screw anchor with a second sense of screw advancement opposite to the first sense of screw advancement.  
      In all embodiments it is possible that the outer introducer and inner introducer are separable, including sliceable, splittable, peelable, or tearable.  
      In yet another embodiment the second anchor is rotatable on and captured by the inner introducer and drivable by an elongate instrument. In this case the apparatus further comprises the elongate instrument and a lumen defined through the inner introducer through which the elongate instrument is disposed. The second anchor is typically, but not necessarily telescopically disposable from the distal end of the inner introducer.  
      The apparatus may further comprise a plurality of first anchors coupled to the inner introducer.  
      The invention contemplates that the inner, or outer both introducers may biased.  
      In an illustrated embodiment the first anchor comprising a fish-hook anchor.  
      The first anchor may be movably coupled to the inner introducer and is deployed when the inner introducer is telescopically advanced out of the distal end of the outer introducer. The first anchor is resiliently dispose within the inner introducer and automatically resiliently deployed when the inner introducer is telescopically advanced out of the distal end of the outer introducer. In one implementation the apparatus further comprises a wire coupled to the first anchor and which is operative when manipulated to rotate the anchor to extend out of or be retracted in the inner introducer. The first anchor is resiliently biased to be normally retracted within the inner introducer and where the wire is operated by applying a tensile force to rotate the first anchor to an extended configuration out of the inner introducer.  
      In still a further embodiment the apparatus further comprises an elongate instrument and a lumen defined through the inner introducer through which the elongate instrument is disposed, the first anchor being a piercing tool coupled to a distal end of the elongate instrument and having at least one barb disposed thereon. The first anchor comprises a plurality of barbs on the piercing tool, which may take the form of a plurality of stiff angled fibers disposed on the piercing tool.  
      In another embodiment the first anchor comprises a hollow needle with an inflatable tip balloon.  
      In still another embodiment the first anchor comprises a bimetallic wire which can be differentially tensioned and curved to form a temporary distal hook.  
      In all of the embodiments the apparatus may further comprise a hemostatic valve coupled to the inner introducer.  
      In yet more embodiments the first anchor is a suction device. In one example, the suction device comprises a suction cavity defined in the inner introducer with a peripheral lip to assist in allowing a suction attachment to the heart tissue. The suction cavity may be positioned on a lateral surface of the inner introducer.  
      The inner introducer has a lumen and the suction device comprises a means for providing suction to the lumen and communicating the suction to the distal orifice of the lumen at the distal tip of the inner introducer. The means for communicating the suction to the distal orifice of the lumen at the distal tip of the inner introducer comprises a central lumen defined through the inner introducer through which central lumen the pacemaker lead is disposed. In another embodiment the lumen is an auxiliary lumen defined through the inner introducer and where the means for communicating the suction to the distal orifice of the lumen at the distal tip of the inner introducer comprises a communication of the lumen with the distal orifice of the lumen at the distal tip of the inner introducer.  
      While the apparatus and method has or will be described for the sake of grammatical fluidity with functional explanations, it is to be expressly, understood that the claims, unless expressly formulated under 35 USC 112, are not to be construed as necessarily limited in any way by the construction of “means” or “steps” limitations, but are to be accorded the full scope of the meaning and equivalents of the definition provided by the claims under the judicial doctrine of equivalents, and in the case where the claims are expressly formulated under 35 USC 112 are to be accorded full statutory equivalents under 35 USC 112. The invention can be better visualized by turning now to the following drawings wherein like elements are referenced by like numerals. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a side cross sectional view of the distal end of an outer introducer comprised of a conventional precurved or biased outer introducer with an unbiased or flexible, but rotationally stiff inner telescopic introducer.  
       FIG. 2  is a side cross sectional view of the distal end of a second embodiment of the telescopic introducer, which is comprised of a biased introducer through which the pacemaker lead with the distal anchor is implanted.  
       FIG. 3  is a side cross sectional view of the distal end of a third embodiment of telescopic introducer which is comprised of a prebiased introducer through which the pacemaker lead with the distal anchor is implanted.  
       FIG. 4  is directed to another embodiment where an outer biased introducer is used to steer to the approximate site in the heart.  
       FIG. 5  is a simplified diagrammatic side cross section view of a human heart: illustrating the pericardial space.  
       FIG. 6  is a simplified diagrammatic, partially cut-away side view of a human heart illustrating the vascular system of the heart.  
       FIG. 7  is a simplified diagram of the venous vascular mesh on the ventricular surface.  
       FIG. 8  is a simplified diagrammatic side cross section view of in enlarged scale of the region in circular dotted outline in  FIG. 3  illustrating dilation of the microvasculature with a balloon.  
       FIG. 9  is a simplified diagrammatic side cross section view of  FIG. 4  showing the disposition of a catheter into the microvasculature.  
       FIG. 10  is a simplified diagrammatic side cross section view of  FIG. 5  showing the disposition of a guidewire and introducer into the microvasculature.  
       FIG. 11  is a simplified diagrammatic side cross section view of  FIG. 5  showing the disposition of a pacemaker lead into the microvasculature.  
       FIG. 12  is a simplified diagrammatic side view of the disposition of an elongate instrument from a first venous bed through the venous vascular mesh and implantation in a second venous drainage area.  
       FIG. 13  is a simplified side cross-sectional view of a heart having a chamber into which an introducer with a suction anchor has been endovascularly disposed.  
       FIG. 14  is an enlarged simplified side cross-sectional view of the distal tip of the introducer of  FIG. 13 .  
       FIG. 15  is a side elevational view of the distal tip of the introducer of  FIG. 14 .  
       FIG. 16  is a diagrammatic side cross-sectional view of another embodiment of a suction anchor where the suction is provided to the distal orifice of catheter either through main lumen between the clearance of lumen and pacemaker lead or through an auxiliary lumen defined in the catheter with a distal communication with lumen at or near orifice.  
       FIG. 17  is a diagrammatic side cross-sectional view of an embodiment wherein suction is provided only through the axial lumen.  
       FIG. 18  is a diagrammatic side cross-sectional view of an embodiment wherein a grabbing tool is provided as the anchor through the axial lumen.  
    
    
      The invention and its various embodiments can now be better understood by turning to the following detailed description of the preferred embodiments which are presented as illustrated examples of the invention defined in the claims. It is expressly understood that the invention as defined by the claims may be broader than the illustrated embodiments described below.  
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       FIG. 1  is a side cross sectional view of the distal end of an outer introducer  10  comprised of a conventional precurved or biased outer introducer  12  with an unbiased or flexible, but rotationally stiff inner telescopic introducer  14 . Alternatively, inner introducer  14  may be biased. Telescopic inner introducer  14  is provided at or near its distal end with a conventional screw-in anchor  16 . Anchor  16  has an inner diameter which is large enough so that when pacemaker lead  18  is telescopically disposed through a axial lumen  42  in inner introducer  14  with its corresponding distal anchor  20 , distal anchor  20  can be telescopically disposed through anchor  16  during fixation into the myocardium without engaging anchor  16 . Being in the preferred embodiment unbiased, inner introducer  14  easily stays on- position at the location defined by the distal end of outer introducer  12  when inner: telescopic introducer  14  is rotated. When pacemaker lead  18  is then rotated and anchored, the support of anchored introducer  14  keeps pacemaker lead  18  supported and similarly on-position at the location defined by the distal end of outer introducer  12 .  
      Once pacemaker lead  18  is implanted, inner introducer  14  can then be unscrewed without dislodging anchor  20  and removed. To enhance the compatibility of adjacent implantations of anchor  20  coaxially inside anchor  16 , anchor  20  and anchor  16  can be provided with helicity of opposite senses. For example, if anchor  20  is a right-hand screw, anchor  16  is provided as a left-hand screw. In this manner, when anchor  16  is unscrewed, it is rotated clockwise when viewed from the proximal end of introducer  10 . Any clockwise rotation transmitted by anchor  16  in any way to anchor  20  thereby serves to screw in or tighten anchor  20 .  
      It must be understood that introducers  12  and  14  may be sliceable, tearable, peelable, or separable in any way now known or later devised, so that they are easily removed over any pacemaker hub or connector (not shown) at the proximal end of pacemaker lead  18 .  
       FIG. 2  is a side cross sectional view of the distal end of a second embodiment of telescopic introducer  10  which is comprised of a biased introducer  22  through which pacemaker lead  18  with distal anchor  20  is implanted. A parallel lumen  32  is defined in the wall of introducer  22  through which a torsional wire  30  is disposed. Wire  30  has a termination  28  which is or can be coupled with a captive screw  34  which has a distal anchor  24 . It is contemplated that screw  34  will be retained within lumen  32  until deployment, at which time it is then distally extended by being pushed by wire-  30  and then rotated by wire  30  to fix anchor  24  into the adjacent myocardium. In this embodiment, anchors  20  and  24  are not telescopic, but are deployed in parallel.  
      It is to be understood that instead of a captive screw  34 , wire  30  and anchor  24  may be integral and simply delivered through auxiliary lumen  32 . A plurality of such auxiliary lumens  32  and wire  30 /anchor  24  combinations may be provided and employed in a radial pattern at the distal end of introducer  22 .  
       FIG. 2  is described above as a nontelescopic system. However, it must be understood as shown in  FIG. 2  that introducer  22  may be biased or unbiased and similarly telescopically disposed through an axial lumen  44  of a biased outer introducer  12 . As in the case of  FIG. 1 , the outer introducer  12  is used to steer inner introducer  22  to the approximately vicinity of the implantation site, inner introducer  22  is telescopically advanced out of introducer  12  and anchored in place. Pacemaker lead  18  is then telescopically advanced in lumen  42  and implanted using anchor  20 .  
       FIG. 3  is a side cross sectional view of the distal end of a third embodiment of telescopic introducer  10  which is comprised of a prebiased introducer  36  through which pacemaker lead  18  with distal anchor  20  is implanted. The distal portion or end of introducer  36  is provided with one or more barbless hooks or “fish hooks”, which are normally resiliently retained within recesses defined in the wall of introducer  36 . Hooks  38  can be deployed by pulling tension wires  40  coupled to hooks  38  to rotate hooks  38  out of the recesses in introducer  36  to a position where they may penetrate radially adjacent myocardium or vascular tissue. Once hooks  38  are deployed by pulling on wires  40 , pacemaker  18  is anchored from the end of anchored introducer  36 . Once pacemaker lead  18  is anchored, the tension on wires  40  is released, allowing springs or other resilient means attached to hooks  38  to return them to their undeployed configuration with recesses within introducer  36 .  
      Again it must be understood that while the embodiment of  FIG. 3  is described above as a nontelescopic system, in another embodiment introducer  36  may be a prebiased on unbiased telescopic introducer disposed through axial lumen  44  in a biased outer introducer  12 . As in the case of  FIG. 1 , the outer introducer  12  is used to steer inner introducer  36  to the approximately vicinity of the implantation site, inner introducer  36  is telescopically advanced out of introducer  12  and anchored in place. Pacemaker lead  18  is then telescopically advanced in lumen  42  and implanted using anchor  20 . Thus, the parallel-lumen screw anchors of and hooks as shown in  FIGS. 2 and 3  respectively can be substituted for the distal screw anchor  16  and single lumen introducer  14  of  FIG. 1 .  
       FIG. 4  is directed to another embodiment where outer biased introducer  12  is used to steer to the approximate site in the heart. Inner biased or unbiased introducer  36  is then telescopically disposed through axial lumen  44  in introducer  12  and position near or adjacent to a position on the heart wall  52  where pacemaker implantation is to occur. In the illustrated embodiment implantation is made into the intra-atrial septum  52  from the right atrium. A wire  48  is disposed in a parallel or auxiliary lumen  46  in inner introducer  36  and extends distally from the end of introducer  36 . The distal end of wire  48  is or is fitted with a solid needle  54  which is able to puncture and to be forced through the smooth wall of intra-atrial septum  52 . Wire  48  is further arranged or fitted with one or more flexible barbs, such as a plurality of flexible, but stiff fibers or filaments  50 , which are biased to angle proximally on wire  48  like a brush. Needle  54  and filaments  50  can thus easily be advanced distally and pushed through intra-atrial septum  52  to serve as a temporary anchor of inner introducer  36  to intra-atrial septum.  52 . Needle  54  may penetrate entirely through intra-atrial septum  52  into the left atrium. Wire  48  resists backing out or being pulled out of septum  52  by means of the proximally directed bias of filaments  50  which act as barbs. However, the anchoring strength is not so great that wire  48  cannot be later manually withdrawn taking needle  54  and filaments  50  with it.  
      With inner introducer  36  temporarily anchored to intra-atrial septum  52 , pacemaker lead  18  with its distal screw anchor  20  is distally extended from axial lumen  42  in introducer  36  and screwed into intra-atrial septum  52 . The anchored inner introducer  36  provides enough purchase or support to allow anchor  20  to be screwed into intra-atrial septum  52  without pacemaker lead  18  backing off or simply bending and collapsing against septum  52 . The stiffness, degree of bias and number of filaments  50  are chosen to provide enough anchoring force that inner introducer  36 , which is frictionally coupled to wire  48  in lumen  46 , cannot be backed out by the reaction force applied to pacemaker! lead  18 , which is frictionally coupled to inner introducer  36  in lumen  42 , by the screwing action of anchor  20  of pacemaker lead  18  into septum  52 . Once pacemaker lead  18  is firmly anchored into or through septum  52 , wire  48 , filaments  50  and needle  54  can be pull out by applying sufficient tension to wire  48  from its proximal end. It must be understood that while the temporary anchoring of wire  48  is shown by means of a plurality of filaments  50 , there are many other equivalent ways by which temporary anchoring of wire  48  can be achieved. For example, needle  54  may be hollow and carry a small inflatable and deflatable tip balloon, or wire  48  and/or needle  54  may be a bimetallic wire which can be differentially tensioned and curved to form a temporary distal hook by means of an electrical current and ohmic heating of the bimetallic wire, or simply by exposure to the body heat.  
       FIG. 18  is another embodiment similar to  FIG. 4  in which instead of the elongate tool or wire  48  in lumen  46  a stylet or other tool  56  is used which is terminated with a grabbing tool  58 . In the illustrated embodiment grabbing tool  58  comprises a set of pincers with one or two movable jaws which are manipulated by stylet  56  to open and close, as well as to be telescopically disposable in lumen  46 . The mechanism used to manipulate tool  58  may be any type of actuation device now known or later devised for actuating one or more opposing jaws, such as a hollow wire with an inner telescoping solid core wire with one jaw fixed to the hollow wire and the second jaw rotated about the first jaw and coupled to the core wire to rotate the second jaw about its pivot point on the first jaw. Alternatively, grabbing tool  58  may have one jaw fixed to the distal end of introducer  36  with the second jaw rotatable about a pivot point also fixed to the distal end of introducer  36  or the first jaw. The two jaws may be resiliently biased to a closed position. Style  56  then takes the form of a tension wire  56  to rotate the second jaw relative to the first jaw to open and close the grabbing tool  58 . In any embodiment grabbing tool  58  is operative to temporarily pinch, seize, or grab hold of some heart or vascular tissue to temporarily fix introducer  36  in place. In the case where stylet  56  is telescopically slid able within lumen  46 , style  56  can be vascularly disposed and grabbing tool  58  actuated to fix it to a location. Introducer  36  is then guided into position over anchored stylet  56  until the distal end of introducer  36  is proximate to or adjacent the tissue site to which the lead  18  is to be implanted. Stylet  56  may then be longitudinally fixed to introducer  36 , such as by a proximal locking or pinching device (not shown), and then lead  18  implanted in a conventional manner with introducer  36  securely but temporarily fixed into position.  
      While this disclosure is directed to the anchoring of a catheter or introducer, it must be expressly understood that the disclosed catheter or introducer includes within its scope any sliceable, splittable, peelable, tearable or separable catheter or introducer. now known or later devised, as well as catheters or introducers, which cannot be separated in any of these manners. In addition, whether or not a hemostatic valve is associated with the catheter or introducer of the invention, and if so, whether or not the hemostatic valve is separable or not, together with or separately from the catheter or introducer, is all expressly included within the scope of the disclosed invention.  
      For example, splittable valves of the type disclosed in Lee, “Splittable Hemostatic Valve and Sheath and the Method for Using the Same”, U.S. Pat. No. 5,125,904 (1992) and 5,312,355 (1994), which are incorporated herein by reference, are included. Catheters and introducers are included of the type as disclosed in: Kurth, “Permanent Catheter with an Exterior Balloon Valve and Method of Using the Same,” U.S. Pat. No. 5,792,118 (1998), “Method and Apparatus for Insertion of Elongate Instruments Within a Body Cavity,” U.S. patent application Ser. No. 09/708,150 (2000), “A Temporarily Secured Guidewire and Catheter for Use in the Coronary Venous System and Method of Using the Same,” U.S. patent application Ser. No. 10/365,890 (2003), “A Method and Apparatus for a Suction-Anchored Introducer for Pacemaker Implantation,” U.S. Provisional Patent Application Ser. No. 60/464,437 (2003), “Method and Apparatus for Implantation of Left Ventricular Pacing Leads Between the Epicardium and Pericardium,” U.S. Provisional Patent Application Ser. No. 60/426,773 (2002), and “A Tool for Placement of Dual Angioplasty Wires in the Coronary Sinus Vasculature,” U.S. Provisional Patent Application Ser. No. 60/408,385 (2002); Worley et.al., “Introducer for Accessing the Coronary Sinus of a Heart,” U.S. patent application Ser. No. 10/139,551 (2002), “A Telescopic, Peel-Away Introducer and Method of Using the Same,” U.S. patent application Ser. No. 10/139,554 (2002), “A Telescopic, Peel-Away Introducer and Method of Using the Same,” U.S. patent application Ser. No. 10/139,554 (2002), “A Telescopic Introducer with a Compound Curvature for Inducing Alignment and Method of Using the Same”, U.S. patent application Ser. No. 10/202,158; and Kurth et.al; I “Introducer and Hemostatic Valve Combination and Method of Using the Same,” U.S. patent application Ser. No. 10/234,686 (2002), “A Compression Fitting for an Introducer Coupled to a Hemostatic Valve,” U.S. patent application Ser. No. 10/277,476 (2002), which are all incorporated herein by reference.  
      Consider now pacemaker anchoring in the pericardial space. As shown in the diagrammatic view of  FIG. 5  the human heart  128  is contained within a conical sac of serous membrane called the pericardial sac or simply the pericardium  124  that encloses the heart and the roots of the great blood vessels of humans and vertebrates in general. The epicardium  126  is the visceral part of the pericardium  124  that closely envelops the heart. In between the epicardium  126  and the outer surface of the cardiac muscle and vasculature is a space lying above the coronary vasculature  112 ,  118  called the pericardial space  122 . This pericardial space  122  may be void or partially filled with a lubricious fluid. In diseased states the pericardium may contain a substantial amount of fluid.  
      A pacemaker lead is implanted in a heart into the pericardial space, on or in the epicardium or in the microvasculature by: disposing an elongate instrument into the venous system of the heart; puncturing the system at a predetermined position or entering the microvasculature of the venous system; disposing the elongate instrument into the pericardial space, epicardium or in the microvasculature at a predetermined location in the pericardial space, epicardium or in the microvasculature; and implanting a pacemaker lead at the predetermined position. It should be clear that the lead can be implanted either into the pericardial space or into the vascular mesh in or on the heart wall surface just adjacent to the pericardial space.  
      The step of implanting a pacemaker lead at the predetermined position comprises implanting the lead in a position on the surface of the left ventricle in a position of optimized pacing efficacy through the venous microvasculature on the ventricular surface or in the pericardial space.  
      In one embodiment the elongate instrument may be disposed into a first venous bed through the vascular mesh and subsequently into a second venous drainage bed for optimal positioning at or near the ventricular surface or adjacent pericardial space.  
      In either case the implanted pacemaker lead is then anchored in the venous microvasculature on the ventricular surface or in the pericardial space.  
      The microvasculature may also be dilated prior to implanting the pacemaker lead in order to allow for access of the guiding instrument or lead.  
      Consider first implantation of a lead into the pericardial space  122 . In this embodiment the invention is directed to a method and apparatus in which a wire, catheter, lead, introducer or other instrument  110  is endovascularly disposed by conventional means into the coronary venous system  112  to a point  120  in the coronary venous system  112  where a puncture of the venous system  112  may take place as depicted in  FIG. 6 .  
      At this point  120 , the coronary vein  116  is punctured or otherwise opened to allow the disposition of the wire, catheter, lead, introducer or other instrument  110  to be disposed through the vein  116  and then inserted, steered or disposed in the pericardial space  122  to the desired location on the heart&#39;s surface, or in this case in the vicinity of the left ventricle  130 . Once in position it is anchored by conventional means in the pericardial space  122 .  
      There are many means whereby the incision or puncture through the wall of vein  116  may be accomplished. A hollow or solid needle  134  shown in  FIGS. 7 and 8  can be disposed through a catheter  110  and positioned at the venous site  120  selected. Advancement of the needle  134  beyond the distal tip of the catheter  110  allows the needle to puncture the vein  116  at the desired location  120 . The vein  116  may also be punctured employing cutting or puncturing probes using ohmic heating, laser light, radiofrequency or microwave heating, ultrasonic or other energy sources, a balloon or blunt probe may also be used to open the vein into the pericardial space.  
      Once the vein  116  is punctured confirmation must be obtained that entry into the pericardial space  122  is accomplished. This can be practiced by injecting a contrast agent through the puncture site  120  into the pericardial space  122 , obtaining an ultrasound image of the field of operation, or inserting a guidewire or other radio opaque means into the puncture site  120  for fluoroscopic confirmation.  
      With confirmation of entry into the pericardial space  122  a guidewire or probe  138  is then advanced into the space  122  through catheter  110 , which may be removed  18  and then followed, if desired, by an introducer or other introducing instrument  140  which is steerable or otherwise navigable to the desired location in the pericardial space  122  adjacent to or proximal to the desired location in the left ventricular wall as shown in  FIG. 10 .  
      Finally, a pacing lead  142  is then brought or disposed at the desired location using the introducer or other introducing instrument  140  or the pacing lead  142  itself may be self-guiding as shown in  FIG. 11 . It is contemplated that once the desired location has been accessed; the pacing lead  142  will be anchored to the site in a conventional manner. Conventional anchoring means  144  can be employed or a mechanism with is optimized to the special environment of the pericardial space can be employed. In the case of patients who have cardiac bypass surgery, the pericardial space  22  often includes adhesive tissues, which provide a naturally adhesive or embedding tissue field and a pericardial-epicardial anchor  144  may not be required or is of less concern.  
      No restrictions or limitations are envisioned as being included which would in any way reduce the scope of the means whereby the wire, catheter, lead or other instrument  110 ,  138 ,  140 , or  142  may be steered, by which the vein  116  is punctured, by which the vein is sealed around the wire, catheter, lead, other instrument,  110 ,  138 ,  140 , or  142  or implanted pacing lead,  142  or by which the implanted pacing lead  142  is anchored at the desired location.  
      Consider now the implantation of a lead into the vascular mesh. Ventricular surface of the heart has disposed therein and/or thereon a microvasculature  132  as diagrammatically shown in  FIG. 7  between the arterial system  118  and venous system  112  forming what comprises a vascular mesh. The vascular mesh is comprised of a multiplicity of small vessel radiating from the more distal portions of the coronary venous system. The vascular mesh subdivides into smaller and smaller multi-branched vessels and ultimately communicates to the capillary system in the heart walls. Blood drains from the heart muscle into the vascular mesh and then into the coronary veins. Generally, a flow path can be found through the vascular mesh communicating one vessel of the coronary venous system with another vessel of the coronary venous system.  
      The microvasculature  132  may also be opened or dilated with a balloon  136  or blunt instrument that opens the distal microvasculature  132  to allow for a catheter or other instrument  110  to be advanced. The balloon  136  may be withdrawn, or a central channel through a balloon catheter  110  may be used to with draw needle  134 , so that another catheter, lead or other instrument  110  can be deployed into the microvasculature  132 .  
      In one embodiment access to the venous system  112  through the coronary sinus is accomplished using a fine, flexible 0.014 inch guidewire  138 . The guidewire  138  is steered through a selected venous path to the very end of a venous bed  146  shown in,  FIG. 12 . At the end of a venous bed  146 , the vascular system  112 ,  118  communicates with an adjacent vascular bed through a vascular mesh  132  located on the epicardium  126  and also communicating with one or more other venous beds  146 ′. Theoretically, a path can be traced through the vascular mesh  32  between any two venous beds  146  and  146 ′ in the entire cardiac vascular system  112 ,  118 . In theory the wire  138  can be advanced through the vascular mesh  132  into an adjacent or another venous bed  146  and ultimately looping back to the coronary sinus.  
      In this manner the wire  138  can be then steered from a first venous bed  146  to a selected position in a second venous bed  146 ′, which position  146  might be accessible or easily accessible through the coronary sinus and the second venous bed  146 ′,  20  accessible as a practical matter only by a path through the coronary sinus  112 , the first venous bed  146 , the vascular mesh  132  and into the second venous bed  146 ′. Therefore, the ideal or desired position for a pacing lead  142  becomes accessible even if located in the second venous bed  146 ′ through the first venous bed  146 .  
      The pacemaker lead  142  is anchored in its position by virtue of its frictional engagement or intimacy with the terminal end of the first venous bed  146  and with the vascular mesh  132 . If necessary, the end of the first venous bed  146  and the vascular mesh  132  can be opened by positioning an angioplasty balloon  136  on the guidewire  138  at the position of terminal constriction of the first and second venous beds  146 ,  146 ′ and in the vascular mesh  132 . This allows for the easy passage then of a pacemaker lead  142  through the terminal constriction of the first and second venous beds  146 ,  14 ′ and the vascular mesh  132 . In some cases an introducer  140  may be disposed through the terminal constriction of the first and second venous beds  146 ,  146 ′ and the vascular mesh  132  and employed to deliver the pacemaker lead  142 . Removal of the introducer  140  leaves the lead  142  anchored in position in the second venous bed  146 ′ by virtue of its embedment in the terminal constriction of the first and second venous beds  146 ,  146 ′ and/or the vascular mesh  132 .  
      Similarly, if the ideal or desired position for a pacing lead  142  happens not to lie in the vicinity of any venous bed, then direct access from the first venous bed  146  through the vascular mesh  32  can be achieved, using a pericardial-epicardial anchor  144  on the pacemaker lead tip. Use of the angioplasty balloon  136  as described above opens up access to the vascular mesh  132  and allows a steerable introducer  140  or lead  142  to then be selectively placed in the vascular mesh.  
      It is further possible that use of the balloon  136  may be used to intentionally rupture the microvasculature  132  allowing the lead  142  to then enter the pericardial  21  space  122  and become anchored therein as described above in a manner similar to venous puncture.  
       FIG. 13  is a simplified side cross-sectional view of a heart  210  having a chamber  212  into which an introducer  214  has been endovascularly disposed. Introducer  214  may be employed in an body cavity or portion of the vascular system. Introducer  214  has a suction anchor portion  218  on its distal end identified in the dotted portion of  FIG. 13  and which is shown in enlarged simplified side cross-sectional view in  FIG. 14 .  
      Introducer  214  is provided with an axial lumen  226  through which a pacemaker lead  228  is or can be disposed. As shown in  FIG. 13  pacemaker lead  228  has a tissue anchor or screw  216  on its distal end for attachment or embedding into the wall of heart  210 . Any type of distal or other anchoring device now known or later devised may be used with pacemaker lead  228  without departing from the spirit and scope of the invention. In general, regardless whatever type of anchoring device  216  is used with pacemaker lead  228 , it tends to push against pacemaker lead  228  and hence against introducer  210  and tends to dislodge or move introducer  210  away from its intended implantation position or configuration.  
      To provide for a noninvasive or nontraumatic anchoring of the distal end of introducer  210 , the invention provides a suction anchor  218  for the distal end of introducer  210  as best shown in  FIG. 14 . Introducer  210  has its distal portion formed so that there is a suction cavity  220  defined therein and opening on one side of introducer  210 . A lumen  222  communicates with cavity  220  and provides a means of providing and maintaining a suction on cavity  220 . The periphery of cavity  220  is provided with a circumscribing lip  224  to facilitate sealing and suction attachment to the wall of heart  210 , even when there are slight irregularities in the wall&#39;s surface as best seen in the side elevational view of  FIG. 15 . The amount of suction applied to cavity  220  is controlled proximally by the surgeon by means of a suction pump (not shown). Introducer  214  is therefore able to temporarily attach itself to a body cavity wall like a sucker fish without traumatic damage to the tissue where attachment is realized. Nevertheless, the degree of attachment is secure, but can be selectively and quickly released.  
      A preferred embodiment is shown in the diagrammatic side cross-sectional view of  FIG. 16  wherein the suction is provided to the distal orifice  234  of catheter  214  either through main lumen  226  between the clearance of lumen  226  and pacemaker lead  218  or through an auxiliary lumen  230  defined in catheter  214  with a distal communication with lumen  226  at or near orifice  234 . To clarify these alternative embodiments,  FIG. 17  is a diagrammatic side cross-sectional view of an embodiment wherein suction is provided only through axial lumen  226 . In either case the suction is provided at the distal orifice  234  of catheter  214  which is position into contact with tissue or heart wall  232 . As seen in  FIG. 16  the suction may draw some to the tissue  236  of wall  232  into orifice  234  and seal directly with wall  232 . Anchor  216  may then be advanced in lumen  226  through orifice  234  and fixed in a conventional manner into tissue  236 . Continuous suction is applied to lumen  226  during the fixation operation so that tissue  236  of wall  232  is kept in position in or adjacent to orifice  234 . After conventional fixation of lead  228  is achieved, the suction is terminated, tissue  236  released, and catheter  214  is removed.  
      The embodiments of  FIGS. 13-15  may require an additional cylindrical introducer to enable the device to be smoothly introduced through the tissue planes and inserted into the vascular system due to the irregularities in outline of the suction anchor on the distal tip of the catheter. While any structures departing from a smooth cylindrical envelope can be made of very soft or pliable materials, they may nonetheless present some resistance to easy introduction. On the other hand the embodiments of  FIGS. 16 and 17  are preferred in that they are completely and smoothly cylindrical in their outer envelope and therefore are adaptable to over the wire techniques without the necessity for an additional introducer. The distal most end of catheter  214  may be modified to include forward extending lips or any other structure which would be beneficial in establishing a suction seal with the tissue.  
      Many alterations and modifications may be made by those having ordinary skill in the art without departing from the spirit and scope of the invention. Therefore, it must be understood that the illustrated embodiment has been set forth only for the purposes of example and that it should not be taken as limiting the invention as defined by the following claims. For example, notwithstanding the fact that the elements of a claim are set forth below in a certain combination, it must be expressly understood that the invention includes other combinations of fewer, more or different elements, which are disclosed in above even when not initially claimed in such combinations.  
      The words used in this specification to describe the invention and its various embodiments are to be understood not only in the sense of their commonly defined meanings, but to include by special definition in this specification structure, material or acts beyond the scope of the commonly defined meanings. Thus if an element can be understood in the context of this specification as including more than one meaning, then its use in a claim must be understood as being generic to all possible meanings supported by the specification and by the word itself.  
      The definitions of the words or elements of the following claims are, therefore, defined in this specification to include not only the combination of elements which are literally set forth, but all equivalent structure, material or acts for performing substantially the same function in substantially the same way to obtain substantially the same result. In this sense it is therefore contemplated that an equivalent substitution of two or more elements may be made for any one. of the elements in the claims below or that a single element may be substituted for two or more elements in a claim. Although elements may be described above as acting in certain combinations and even initially claimed as such, it is to be expressly understood that one or more elements from a claimed combination can in some cases be excised from the combination and that the claimed combination may be directed to a subcombination or variation of a subcombination.  
      Insubstantial changes from the claimed subject matter as viewed by a person with ordinary skill in the art, now known or later devised, are expressly contemplated as being equivalently within the scope of the claims. Therefore, obvious substitutions now or later known to one with ordinary skill in the art are defined to be within the scope of the defined elements.  
      The claims are thus to be understood to include what is specifically illustrated and described above, what is conceptionally equivalent, what can be obviously substituted and also what essentially incorporates the essential idea of the invention.