Abstract:
An electrode probe for medical applications includes a tubular, flexible probe body, an electrode mounted at the distal end of the probe body, and an electrical supply line within the probe body and extending to the electrode. At least a portion of the distal end section of the probe body can be transformed into a radially broadened collar, preferably owing to relative motion between the electrical supply line and the probe body. Where a screw-in electrode is used, the distal end section may be deformed into a radially broadened collar when the electrode is screwed into the body tissue, owing to forces exerted by the body tissue onto the distal end section, and/or owing to forces exerted by the screw-in electrode on the distal end section via a thrust bearing.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority under 35 USC §119(e) to U.S. Provisional Patent Application 61/219,434 filed 23 Jun. 2009, the entirety of which is incorporated by reference herein. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates generally to medical probes, with a preferred version of the invention relating more specifically to an implantable electrode probe with a tubular, flexible probe body, an electrode mounted at the distal end of the probe body, and an electrical supply line guided in the probe body to the electrode. 
       BACKGROUND OF THE INVENTION 
       [0003]    Electrode probes are routinely used, for example, as coronary pacemaker electrodes. They are variously described in patent literature, with examples being the patent publications DE 10 2005 039 040 A1, DE 198 00 697 A1, DE 20 2006 020 517 U1 and EP 88730200.8. 
         [0004]    Probes that can be implanted in the body, especially electrode probes, should have a probe diameter as small as possible to ensure comfortable passage through the insertion site and blood vessels up to the desired implant site, and to better enable the use of small insertion tools. However, probes with small diameter increase the danger of causing unwanted perforation of body tissue at the implant site. 
         [0005]    As known in the field, active ingredients can be administered by the probe, particularly an electrode probe, at the implant site. For example, in U.S. Pat. No. 5,571,163 A and U.S. Pat. No. 5,324,324 A1 it is proposed that the electrode tip be coated with anti-inflammatory medications in order to locally counteract the tissue irritation caused by the probe. In the case of electrode probes with a relatively small probe diameter, the small probe surface disadvantageously limits the area available for administering the active ingredient. Additionally, if the same amount of active ingredient is to be used on a smaller probe diameter, the reservoir of active ingredient extends over a larger length of the probe so that portions of the active ingredient are released at a relatively far distance from the implant site, which can reduce the therapeutic utility of the active ingredient. 
         [0006]    Therefore, there is a desire for a solution to the competing objectives of obtaining an optimal electrode probe diameter for ease of implantability of the probe, and a suitable configuration for local discharge of active ingredient by the probe. 
       SUMMARY OF THE INVENTION 
       [0007]    An objective of the invention is to provide an implantable electrode probe that has a small probe diameter in order to better ensure comfortable implantation, but also offers high safety against perforation, and also makes efficient discharge of active ingredient possible at the implant site, i.e. at locations at which the probe can irritate tissue. The invention involves an electrode probe for medical applications—e.g., a coronary pacemaker electrode, an electrode for nerve stimulation, an electrode for the measurement of brain potential, or the like—includes a tubular, flexible probe body; an electrode mounted at the distal end of the probe body (for example, a tip electrode); and an electrical supply line that is guided in the body of the probe. One or more electrical contacts can be mounted along the probe body. At least a part of the distal end section of the probe body—preferably at a part directly next to the electrode—can be transformed by a displacement mechanism between a first radially narrower condition and a second radially broader condition. In the second condition, the distal end section of the probe body is radially broadened in relation to the remainder of the probe body and the electrode. 
         [0008]    The electrode probe can thus be implanted with a thin distal end section, allowing more comfortable passage through the insertion gateway and blood vessels owing to the smaller radial dimension of the distal end section of the probe body. On the other hand, the distal end section of the probe body can be radially broadened at the implant site, thereby deterring tissue perforation and also providing a relatively large surface for local discharge of an active ingredient at the implant site. In addition, because of the spatial proximity (or contact) of the broadened area at the distal end section to the implant site, the active ingredient can be discharged directly at the site of the tissue irritation, achieving high therapeutic efficiency. Moreover, compared to a distal end section of the probe body that is not broadened, a greater amount of active ingredient can be provided at or close to the implant site. 
         [0009]    Throughout this document, the term “axial” will generally be used to describe directions along the length of the electrode body (inner tube), and the term “radial” will generally be used to describe directions perpendicular to the length of the electrode body. 
         [0010]    In a preferred version of the electrode probe, the electrode mounted at the distal end of the probe body is mechanically coupled at least in an axial direction with the distal end section of the probe body, for example, by being connected with and/or engaged behind the distal end section, and the electrical supply line to the electrode is displaceable in an axial direction relative to the probe body. The distal end section of the probe body is designed in such a way that at least a part of the distal end section can be deformed into a radially broadened collar by a force that is transmitted by the electrode to the distal end section (for example, by manually effecting relative motion between the electrical supply line and the probe body). The distal end section is resiliently flexible and/or elastic to effect the deformation into the broadened state. Thus, the electrode probe can be implanted at the implant site with a non-broadened distal end section, and by then generating relative motion between the electric supply line and the probe body, the distal end section can be radially broadened. 
         [0011]    In an advantageous version of the electrode probe, a casing surrounds at least a portion of the probe body, and is mechanically coupled to the distal end section in such a way that the distal end section can be deformed into the radially broadened collar as a result of relative motion between the electrical supply line and the casing (as by pushing the collar forwardly with respect to the supply line, and/or by pulling the supply line rearwardly with respect to the casing). 
         [0012]    The electrode may be designed as a screw-in electrode for screwing into body tissue, for example, heart tissue, whereby rotation of the electrical supply line can displace the electrode between a passive setting within the probe body and an active setting at least partially outside of the probe body. Screw-in anchoring of an electrode is known, for example, from DE 20 2006 020 517 U1. At least a portion of the distal end section of the probe body is deformable into a radially broadened collar upon screwing the electrode into body tissue as the result of forces exerted on the deformable distal end section. Thus, the collar is formed in the distal end section of the probe body during screwing in of the electrode. The electrode probe can be positioned at the implant site with a non-broadened distal end section, and the distal end section can be radially broadened by screwing the electrode into the body tissue. 
         [0013]    A screw-in electrode as described above can be displaced between the passive setting and the active setting by cooperating with a thrust bearing (“pitch provider”) mounted in the area of the distal end section at the probe body, during rotation of the supply line. Such a pitch provider is described in the aforementioned DE 20 2006 020 517 U1. The distal end section is designed in such a way that it can be deformed into a radially broadened collar by interaction between the screw-in electrode and the thrust bearing upon rotation of the supply line. The collar can thereby be easily and automatically formed in the distal end section of the probe body by rotating the supply line, with the collar being formed by the pressure exerted by the body tissue on the distal end section, and by the force transmitted by the thrust bearing to the distal end section. The electrode probe can therefore be positioned at the implant site with a non-broadened distal end section which is then radially broadened during anchoring by screwing the electrode into the body tissue, and by the transmission of force to the thrust bearing. 
         [0014]    In an advantageous version of the electrode probe, at least a portion of the distal end section of the probe body bears through-holes which define lamellae (e.g., strips or fingers) extending in the axial direction, and which deploy into a radially broadened state. This can achieve simple formation of the collar with a relatively large radial broadened area. 
         [0015]    In another advantageous version of the electrode probe, the distal end section of the probe body has several broadening components on its outer surface that can be displaced between a passive setting in which they abut the outer surface at the distal end section, and an active setting in which they extend from the distal end section in the radial direction. The broadening components may be coupled with a mechanical pre-loading tool, for example, a spring tool, that pre-loads the components into their active setting. A sleeve-shaped insertion tool can be used to force the broadening elements into their passive position, and after implantation, the insertion tool can be removed from the implanted electrode probe to move the broadening elements into their active setting. 
         [0016]    The outer surface of the distal end section of the probe body can be provided with at least one active ingredient to be discharged into the body tissue, as by providing the active ingredient as a coating of the outer surface of the distal end section. This can achieve targeted local discharge of active ingredient near or in contact with the body tissue at the implantation site, whereby the therapeutic effectiveness of the discharged active ingredient is improved. 
         [0017]    The distal end section of the probe body may include a discharge device connected with at least one active ingredient reservoir for discharging at least one active ingredient into the body tissue. This can also achieve targeted local discharge of active ingredient near or in contact with the body tissue at the implant site. 
         [0018]    Alternatively or additionally, the electrode may be provided with a discharge device connected with at least one active ingredient reservoir for discharging at least one active ingredient into the body tissue at the implantation site. This can also provide targeted local discharge of active ingredient near or rather in contact with the body tissue at the implant site to enhance the therapeutic effectiveness of the discharged active ingredient. The active ingredient reservoir(s) can be compressed by a displaceable piston or other tool in order to effect transport of the active ingredient from the active ingredient reservoir to the discharge device. The compression means for compressing the active ingredient reservoir may be displaceable by coupling a swellable material to the compression means. A wall of the compartment for housing the swellable material may have one or more permeable openings for admitting liquid for swelling the swellable material. The available area of the liquid-admitting openings may be varied as the compression means displaces, such that the rate of swelling (and thus the motion of the compression means) may be varied with the position of the compression means. 
         [0019]    Where a reservoir of active ingredient is provided, it is useful if the reservoir is housed in the probe body. 
         [0020]    If a discharge device for discharging at least one active ingredient is used, it can be useful if the reservoir of active ingredient is in fluid connection with an electrically operated pump for supplying the active ingredient to the active ingredient discharge device. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0021]    Exemplary versions of the invention are now explained in detail with reference to the accompanying drawings, wherein the same or functionally similar elements are labeled with the same legend. Shown are: 
           [0022]      FIG. 1A-1B  schematic perspective views of an exemplary first version of the electrode probe; 
           [0023]      FIG. 2A-2C  schematic perspective views of a variation of the first exemplary version of the electrode probe; 
           [0024]      FIG. 3A-3D  schematic views of a second exemplary version of the electrode probe; 
           [0025]      FIG. 4A-4C  schematic views of a third exemplary version of the electrode probe; 
           [0026]      FIG. 5A-5D  schematic views of a variation of the second or third exemplary version of an electrode probe; 
           [0027]      FIG. 6A-6F  schematic views of variants of the electrode tip for use in further designs of the electrode probe. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0028]    A first exemplary version of the electrode probe is schematically illustrated in  FIGS. 1A and 1B . An electrode probe  1  designed, for example, for use as a heart pacemaker electrode, includes a tubular bendable probe body  2  with a distal end section  3  and a proximal end section  4 , wherein the latter may include a standard connection (not shown) for connecting electrode probe  1  with a heart pacemaker (also not shown). The axial direction of the probe body  2  is defined by its direction of extension (its length), whereas the radial direction of the probe body is oriented perpendicular to its length. 
         [0029]    At a facing surface  5  or otherwise on the distal end section  3  of the probe body  2 , an at least substantially half-spherical tip electrode  6  is engaged radially about the distal end of the probe body  2 , so that a force can be transmitted in the axial direction between the tip electrode  6  and the distal end  3  of the probe body  2 . The probe body  2  forms a lumen housing an interior conductor  7 , and a first isolation sleeve  8  made of an insulating material surrounds the conductor  7 , wherein the conductor  7  and sleeve  8  can jointly be considered to be the “inner part” of the probe body  2 . The interior conductor  7 , which may be provided as a wire helix or in other forms, makes contact with the tip electrode  6  as an electrical supply line. 
         [0030]    An exterior conductor  9 , which can also be designed (for example) in the form of a wire helix, is surrounded by an isolation sleeve  10  (only partially shown) and extends as an electrical supply line to make contact with a ring electrode  11  located proximal to the distal end section  3 . As illustrated in  FIG. 1A , for example, the exterior conductor  9  can be spiraled onto a block  13  that lies between the distal end  3  and the proximal end  4  of the probe body  2 . The exterior conductor  9  and the second isolation sleeve  10  can jointly be considered to be the “exterior part” of the probe body  2 . 
         [0031]    The interior part of the probe body  2  (the conductor  7  and/or sleeve  8 , as defined above) is displaceable relative to the exterior part of the probe body  2  (the exterior conductor  9  and/or the second isolation sleeve  10 ) in an area between the distal end section  3  and the proximal end section  4 . At the distal end section  3  of the probe body  2 , the tip electrode  6  is connected with the probe body  2 . At the area of the proximal section  4 , the interior part of the probe body  2  may be connected to the exterior part of the probe body  2 . 
         [0032]    In the area of the distal end section  3 , a number of anchor elements  12  are distributed circumferentially about the exterior surface of the probe body  2 . These anchor elements  12  may take the form of tips (“tines”), and may be oriented at an angle of, for example, approximately 30° to the proximal end section  4  of the probe body  2 . The anchoring elements  12  may serve in a known manner for so-called passive anchoring of the electrode probe  1  in the ventricular trabecular meshwork. 
         [0033]    As is shown in  FIG. 1B , and as indicated by an arrow in the axial direction, the distal end section  3  of the probe body  2  can be deformed by displacing the exterior part (exterior conductor  9  and/or the second isolation sleeve  10 ) in a distal direction relative to the interior part of the probe body  2  (the conductor  7  and/or sleeve  8 ) into a circular collar  14 , which radially broadens the probe body  2  and tip electrode  6 . The collar  14  is directly next to tip electrode  6 . The distal end section  3  of the probe body  2  is designed to be correspondingly resilient for this purpose. 
         [0034]    The exterior surface of the distal end section  3  of the probe body  2  is preferably coated with at least one pharmaceutically active substance (active ingredient), which can be discharged to the surrounding coronary tissue. The active ingredient might only be applied to that part of collar  14  that is aligned toward the coronary tissue. For purposes of dispensing the active ingredient, the distal end section  3  is preferably formed of (for example) a biocompatible polymer such as (again for example) silicone rubber and polyurethane, or of a material that can be resorbed and which releases the active ingredient on a delayed basis during decomposition. In principle, the distal end section  3  can be coated with any active ingredient, with preferred ingredients being anti-inflammatory steroids (glucocorticoids), especially alclomethason, amcinonide, beclomethasone, betamethasone, budenoside, ciclesonide, clobetasol, clobetasone, clocortolone, cloprednol, cortisol, cortisone, deflazacort, desonide, desoximethasone, dexamethasone, diflorasone, diflucortolone, fludroxycortide, flumetasone, flunisolide, fluocinolon, fluocinonide, fluocortin, fluocortolone, fluorometholone, fluprednides, fluticasone, halcinonide, halometasone, hydrocortisone, medrysone, methylprednisolone, mometasone, prednicarbate, prednisolone, prednisone, prednylides, rimexolone, tixocortol, triamcinolone, as well as derivatives thereof. Derivatization can be performed especially as aceponate, acetate, acetate-propionate, acetonide, benzoate, buteprate, butyrate, butyrate-propionate, diacetate, dihydrogenphosphate, dipropionate, ethyl carbonate propionate, hydrogensuccinate, hexacetonide, isonicotinate, palmitate, phosphate, pivalate, propionate, sodiumphosphate and valerate. The active ingredient can be dissolved or suspended in a matrix. A possible dose is, for example, in the range of 0.01 to 1,000 mg. 
         [0035]    The electrode probe  1  schematically shown in  FIGS. 1A and 1B  can be implanted in straightforward fashion with a “thin”, i.e. un-broadened distal end section  3 , of the probe body  2 . After implantation, deformation can take place, for example, by manual displacement of the exterior part of the distal end section  3  in a distal direction relative to the interior part, thereby deforming the distal end section  3  to define the ring-shaped collar  14 , with the radial broadening providing effective protection against perforation of the coronary tissue. As a result of the circular collar  14 , at least one active ingredient, particularly a steroid, can be discharged near to or in contact with the coronary tissue, whereby high therapeutic effectiveness of the applied dosage can be achieved. 
         [0036]    It is also possible to apply a cladding to the probe body  2  that is connected with the distal end section  3  of the probe body  2 , whereby displacement of the distal end section  3  in a proximal direction forms the circular collar  14  relative to the interior part. Fixation of the collar  14  into its expanded form could be accomplished by affixing the interior and exterior parts of the probe body  2  together, as by use of a crimping/fixation sleeve (not shown) to which electrode probe  1  is mounted near the pacemaker pocket. 
         [0037]    It would also be possible to create a spring tool consisting of, for example, nitinol in the distal end section  3  of the collar  14 , whereby the electrode probe  1  is implanted with an insertion tool which is removed after the implantation so that the collar  14  can expand subject to the effect of the spring tool. 
         [0038]      FIGS. 2A to 2C  respectively show schematic perspective views of a variant of the first exemplary version of the electrode probe  1 . In order to avoid unnecessary repetition, only the differences with the exemplary version shown in  FIGS. 1A and 1B  are now discussed.  FIGS. 2A and 2B  show a perspective lateral view of the distal part of the probe body  2 , and  FIG. 2C  is a view of the same from the front. 
         [0039]    The distal end section  3  of the probe body  2  is provided with a number of axial strips or lamellae  16  distributed in the circumferential direction. To form the lamellae  16 , slots  15  are defined along the distal section  3 . If the exterior piece is then displaced in a distal direction relative to the interior piece, the lamellae  16  then protrude to form the collar  14 . Based on the lamellar structure of the distal end section  3 , the collar  14  can be generated via application of a relatively small force, and the lamellae  16  can be deformed into a relatively broad collar  14  in the radial direction. As indicated by the arrow in  FIG. 2B , by rotating the probe body  2  in a circumferential direction, it can also be achieved that not only the exterior surfaces  17  of the lamellae  16  of the collar  14  but also the interior surfaces  18  come in contact with the coronary tissue. If the interior surfaces  18  of the lamellae  16  are coated with an active ingredient, the surface of the collar  14  that is used for discharging active ingredient to the myocardium can thereby be enlarged in order to improve the therapeutic efficiency of the active ingredient. 
         [0040]      FIGS. 3A to 3D  schematically illustrate the distal part of the second exemplary version of the electrode, with  FIG. 3A  showing an axial cross section view, and  FIGS. 3B-3D  respectively showing perspective views of the distal part of the probe body  2 . 
         [0041]    In  FIGS. 3A to 3D , the electrode mounted at the distal end of the probe body  2  is designed in the form of a corkscrew-like (i.e. helical) electrode  19  for screwing into the myocardium  21 . The screw-in electrode  19  is rotatably mounted in the lumen of the probe body  2  and connected with interior conductor  7 , which has sufficient torsion stiffness that it may transmit torsion to the screw-in electrode  19  for screwing into the myocardium  21 . The screw-in electrode  19  acts jointly with a thrust bearing  20  (pitch-provider), which is mounted on an interior side of distal end section  3  of the probe body  2 . If the interior conductor  7  is rotated, the screw-in electrode  19  can be displaced between a passive position shown in  FIG. 3A , in which it is located within the probe body  2 , and an active position shown in  FIG. 3B , in which it is in part positioned outside of the probe body  2 . When screw-in electrode  19  is rotated out of the probe body  2  it exerts a force in the axial direction toward the proximal end  4  of the probe body  2 . The mechanism for activating the screw-in electrode  19  is known in the field, for example, from DE 20 2006 020 517 U1. 
         [0042]    If the electrode probe  1  is anchored at the implant site by screwing in electrode  19  into coronary tissue  21 , the tissue exerts a proximally-oriented counter-force upon the distal facing surface  5  of the distal end section  3  of the probe body  2 . Likewise, upon rotating screw-in electrode  19  out of the probe body  2 , the thrust bearing  20  exerts a proximally-oriented force on the distal end section  3 . Both effects contribute to deformation of the distal end section  3  into a radially broadened collar  14  during the screwing in of screw-in electrode  19 , as illustrated in  FIGS. 3B-3D .  FIG. 3D  shows electrode probe  1  anchored in coronary tissue  21 , with the collar  14  having a two-dimensional area abutting the coronary tissue  21 . The distal end section  3  is provided with sufficient deformability to make formation of a collar possible. 
         [0043]    The electrode probe  1  illustrated in  FIGS. 3A and 3D  can thus be implanted in a comfortable manner with a cylindrical distal end section  3  of the probe body  2 , and with the screw-in electrode  19  being housed in the lumen of the probe body  2  (see  FIG. 3A ). When the electrode  19  is screwed in at the implant site to anchor the electrode probe  1 , the distal end section  3  of the probe body  2  radially enlarges as it axially shortens, forming circular collar  14  that radially broadens probe body  2 . The face of the collar  14  abuts the surface of the coronary tissue  21  (see  FIG. 3D ). The collar  14  thus provides perforation protection, deterring perforation of the coronary tissue  21  by electrode probe  1 . 
         [0044]    By coating an exterior surface  22  ( FIGS. 3C-3D ) of the collar  14  that faces the coronary tissue  21  with an active ingredient (for example, a steroid), the active ingredient can be discharged to the site of tissue irritation by being targeted locally to the area  22  in direct contact with the coronary tissue  21 , so that high therapeutic efficiency can be achieved. 
         [0045]      FIGS. 4A to 4C  show the distal part of a third exemplary version of the electrode probe, wherein  FIGS. 4A and 4B  respectively show an axial cross section and  FIG. 4C  shows a perspective view of the distal part of electrode probe  1 . 
         [0046]    In  FIG. 4A , at the tubular distal end section  3  of the probe body  2 , extensions defined as finger-like lamellae  45  are radially distributed about the probe and hingedly mounted at the outermost tip of the probe, and abut the probe tip along their lengths. As a result of screwing in the electrode  19  at the implantation site, a sleeve  46  (pitch-provider) slides in the direction of arrow  47  under the lamellar extensions  45 , whereby the extensions  45  swing radially upright in the direction of arrow  48 . The radially upright extensions—shown at  49  in FIGS.  4 B and  4 C—abut the coronary tissue after installation of the probe. The sleeve  46  which slides under extensions  45  to deploy them can be shaped distally like a cone to ease slipping the sleeve  46  under the lamellae  45 . The exteriors of the extensions  45  can be coated with an active ingredient. 
         [0047]    Alternatively, by displacing the exterior part over the interior part (as discussed above with respect to  FIGS. 1A  and B), a sleeve  46  which is firmly connected with the displaceable exterior piece can be slid under the lamellae  45 , whereby these are put upright in the radial direction. 
         [0048]      FIGS. 5A to 5D  schematically illustrate another feature which may be incorporated in the foregoing probes. Here not only collar  14  (which is not shown for sake of simplicity), but also the screw-in electrode  19 , may discharge at least one active ingredient. The electrode  19  has an internal passageway  25  connected to an opening  26  of a reservoir  23 . A distal section  29  of the electrode  19  serves to anchor the electrode probe  1  in coronary tissue  21 , and it bears pores  30  that open into the passageway  25 . An active ingredient can be discharged through these pores  30  to the surrounding area, particularly when the electrode probe  1  is anchored to the coronary tissue  21 . 
         [0049]    The active ingredient reservoir  23  is defined by the housing wall  24 , a piston  27 , and an opposing distal facing surface  32 . An active ingredient  31 —for example, a steroid—can be discharged from the reservoir  23  through the pores  30  in the screw-in electrode  19 . The piston  27  can be displaced within the housing wall  24  in the axial direction, and can be bounded on its side opposite the reservoir  23  with a swellable material  34  ( FIG. 5A ) such as cellulose, alginate, starch, or their derivatives or similar materials. The swellable material  34  is housed in a compartment  28  formed within the housing wall  24  adjacent the piston  27 . The active ingredient reservoir  23  and the compartment  28  for the swellable material  34  are housed in the lumen of the probe body  2 . 
         [0050]    As illustrated in  FIGS. 5B and 5C , the swellable material  34  can be made to swell upon contact with a liquid, e.g., blood, to displace the piston  27  in the axial direction. As a result, the active ingredient reservoir  23  is compressed and the active ingredient  31  is pressed through the pores  30  for discharge from the screw-in electrode  19 . The housing wall  24 , or rather the outer casing  35  of the probe body  2 , may be provided with a number of openings  36  ( FIG. 5D ) to allow fluid to reach the swellable material  34 . The openings  36  can be distributed in such a way that the sum of the diameters of the openings  36  along the direction of motion of the piston  27  is dependent on the position of the piston  27 , such that fluid inflow changes in a controlled manner as the piston  27  moves. 
         [0051]    Alternatively, the expanding compartment  28  could be loaded pneumatically or hydraulically with a pump. It would alternatively or additionally be possible to provide a non-pressurized passive diffuse discharge of active ingredient from the active ingredient reservoir  23 , or discharge via an electrical potential, for example by an iontophoretic transport. Within the active ingredient reservoir  23 , the active ingredient  31  can be present alone or embedded into a (possibly swellable) matrix. 
         [0052]    In  FIGS. 6A to 6F , schematic views of several variants are illustrated. Here, both the collar  14  (not shown for sake of simplicity) and the tip electrode  6  are designed to discharge at least one active ingredient. The tip electrode  6  is provided with a cavity  36  that serves as an active ingredient reservoir, and which is connected in a fluid-conveying manner to a fluid pump. The active ingredient can be discharged through the fluid pump by the tip electrode  6 . 
         [0053]    In the variant shown in  FIG. 6A , at the distal end of cavity  36 , a gasket  37  is located with two sealing lips  38  pre-loaded to close, and which can be pushed apart (in the direction of the arrows) against the loading force by the pressurization of the fluid transported by the fluid pump. This opens a passage  39  for discharge of the active ingredient to the surrounding area. 
         [0054]    In the variant shown in  FIG. 6B , the cavity  36  is provided with an open distal end  40 , so that the fluid active ingredient can be discharged to the surrounding area upon the application of corresponding pressurization by the fluid pump. 
         [0055]    In the variant shown in  FIG. 6C , the distal end of cavity  36  is provided with a membrane  41  so that upon pressurization of the fluid pump, the active ingredient can be discharged to the surrounding area. The membrane  41  can (for example) be a porous membrane, or a closed membrane that allows diffusion of active ingredient. 
         [0056]    In the variant shown in  FIG. 6D , a gasket  42  similar to the lips  38  of  FIG. 6A  is mounted at a distance from the distal end of cavity  36 . Upon pressurization of the fluid transported by the fluid pump, the gasket  42  may open in order to discharge active ingredient through the open distal end  40  of cavity  36 . 
         [0057]    In the variant shown in  FIG. 6E , the distal end of cavity  36  is provided with a stopper  43  of a sintered material that is suitable for discharging active ingredient so that upon pressurization by the fluid pump, an active ingredient can be discharged to the surrounding area. 
         [0058]    In the variant shown in  FIG. 6F , the distal end of cavity  36  is provided with a cover  44  of wire gauze, so that upon pressurization by the fluid pump, an active ingredient can be discharged to the surrounding area. 
         [0059]    In the variants shown in  FIGS. 6A to 6F , the discharge of active ingredient can be controlled by a fluid pump housed in the coronary pacemaker. Such a fluid pump can be supplied by the power supply of the coronary pacemaker, and controlled by the electronic control unit of the coronary pacemaker. In such an arrangement, the discharge of active ingredient can be adjusted to the current status of the inflammation. It is also possible to discharge several active ingredients for which a number of cavities  36  might be provided in the tip electrode  6 . It would also be possible to provide one or more reservoirs for active ingredient in the coronary pacemaker that are connected to at least one fluid-conveying cavity  36 . While the variants shown in  FIGS. 6A to 6F  are described in connection with the tip electrode  6 , these can equally be incorporated into a screw-in electrode  19 . 
         [0060]    The active ingredient used in the invention is preferably selected from the following classes of medications: antimicrobial, antimitotic, antimyotic, antineoplastic, antiphlogistic, antiproliferative, antithrombotic and vasodilatory substances. 
         [0061]    Especially preferred active ingredients are triclosan, cephalosporin, aminoglycoside, nitrofurantoin, penicillins such as dicloxacillin, oxacillin as well as sulfonamide, metronidazol, 5-fluoruracil, cisplatin, vinblastine, vincristine, epothilone, endostatin, verapamil, statins such as mevastatin, cerivastatin, atorvastatin, simvastatin, fluvastatin, pitavastatin, pravastatin, rosuvastatin as well as lovastatin, angiostatin, angiopeptin, taxane as well as paclitaxel, immunosuppressives or immunomodulators as well as, for example, rapamycin or its derivatives such as biolimus, everolimus, deforloimus, novolimus, methotrexat, colchicine, flavopiridol, suramin, cyclosporin A, clotrimazole, flucytosin, griseofulvin, ketoconazole, miconazole, nystatin, terbinafine, steroides, sulfasalazine, heparin and its derivatives, urokinase, ppac, argatroban, aspirin, abciximab, synthetic antithrombin, bivalirudin, enoxoparin, hirudin, r-hirudin, protamine, prourokinase, streptokinase, warfarin, flavonoids such as 7,3′,4′-trimethoxyflavone, sartane as well as dipyramidol, trapidil, and nitroprusside. 
         [0062]    The active ingredients can be used individually, or combined in equal or various concentrations. 
         [0063]    As has been explained above in regards to the exemplary versions, the invention provides perforation protection via a radially broadened structure in the distal end section of the probe body adjacent the electrode that is mounted at the distal end of the electrode probe. Therapeutically efficient, local discharge of active ingredients at the site of tissue irritation can be achieved by the discharge of active ingredients via the radially broadened structures, and/or via the electrode mounted at the distal end of the electrode probe. Particularly when a screw-in electrode is used, traumatization of the coronary tissue can occur as a result of the insertion of the screw-in electrode, particularly at the tissue surrounding the implant. As a result of a discharge of anti-inflammatory active ingredients by the screw-in electrode, the active ingredients are placed at the target location. In addition to faster application, higher concentrations of active ingredients can be achieved in the target tissue, as the diffusion from the endocardium into the myocardium takes place on a delayed basis. Extraction of the released active ingredient by the circulation of blood in the heart is also prevented. Extraction of the released active ingredients tend to be most pronounced in the first days after the implantation, as the tip of the electrode is still exposed or not yet grown in. At the same time, however, inflammation is at its peak. 
         [0064]    It will be apparent to those skilled in the art that numerous modifications and variations of the described examples and versions are possible in light of the foregoing discussion. The disclosed examples and versions are presented for purposes of illustration only. Therefore, it is the intent to cover all modifications and alternate versions that are literally or equivalently encompassed by the following claims.