Patent Publication Number: US-2006009828-A1

Title: Bipolar cardiac pacing wire with auxiliary pole

Description:
Related Application  
      The present application claims priority to French Application No. 04 04850 filed May 5, 2004.  
     TECHNICAL FIELD  
      This invention relates to bipolar cardiac pacing wires having an external temporary auxiliary pacing pole that allows the casing of the pacemaker to be replaced without the necessity of interrupting the pacing of the heart.  
     SUMMARY OF THE INVENTION  
      The goal of the invention is to simplify the design of cardiac pacing wires and to make access to the auxiliary pacing pole easier and more efficient.  
      To this end, the object of the invention is a bipolar cardiac pacing wire with colinearly coiled leads and with an auxiliary pole, the auxiliary pole being connected to one of the two connectors linking the wire to the pacemaker casing by a third lead colinearly coiled with the two leads of the wire.  
      This colinear arrangement of the three leads of the wire is an elegant solution to the placement of the three leads and their connections, especially as regards the lead assigned to the auxiliary pacing pole which is shunted to the most suitable location of the wire, for example to the junction between the cord of the wire and the tip of the connection to the pacemaker casing.  
      The pacing wire maintains a reduced diameter due to the colinearity of the three leads over the entirety of the common path, and it has high reliability.  
      The auxiliary lead is preferably connected to the wire connector, which is coupled to the distal pacing electrode, but it could be connected to the other connector coupled to the proximal electrode.  
      The invention likewise relates to structures of the auxiliary pacing pole that are suited to this new type of pacing wire.  
      Other characteristics and advantages will become apparent from the following description of embodiments of the invention, given by way of example only and with reference to the attached drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a schematic diagram depicting the pacing wire in accordance with the invention;  
       FIG. 2  depicts the manner in which the distal electrode of the lead of the auxiliary pole and one of the two leads of the pacing wire are connected to the connector;  
       FIG. 3  depicts an alternative connection of the lead of the auxiliary pole;  
       FIG. 4  depicts the branching zone of the wire with its auxiliary pole;  
       FIG. 5  depicts how the wire in use;  
       FIG. 6  depicts a first embodiment of the auxiliary pole; and  
       FIGS. 7 and 8  depict a second embodiment of the auxiliary pole.  
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS  
      In  FIG. 1 , a bipolar pacing wire in accordance with the invention is annotated  1 , with its tip  2  for connection to the pacemaker casing (not shown), showing a first connector D for connecting the pacemaker to distal electrode E D  of the wire and a second connector P for connection to proximal electrode E P .  
      The two leads of wire  1  are conventional and are of the colinear type, that is, two leads having the same diameter wound in closed interleaved coil.  
      For this reason the leads are composed of a central conductive core, wrapped in an insulating sheath, the colinearity making it possible to significantly reduce the diameter of wire  1 , for example, to 1.7 mm instead of 2.3 mm for conventional wires with two spiral coaxial leads of different diameters.  
       FIG. 1  shows three colinear leads labeled  1 ,  2  and  3  respectively. Lead no. 1 is the lead of the auxiliary pole and is thus electrically connected to connector D in the embodiment of  FIG. 1 . The other end of conductor no. 1 emerges from the common winding and is insulated at A, this end A being electrically connected to auxiliary pole P A  (not shown in  FIG. 1 ).  
      Lead no. 2 is likewise electrically connected to connector D; however, its other end will be connected to distal electrode E D , as shown in  FIG. 1 .  
      Lead no. 3 is the lead of the wire connecting connector P to proximal electrode E P .  
       FIG. 2  shows one mode of electrical connection between connector D composed of a metal tubular sleeve, within which two colinear leads no. 1 and no. 2 are located, and of which ends E 1  and E 2  are soldered to a supported sleeve fitted in the internal space to the leads, and whose head  5  closes the end of sleeve D, the head being laser-welded to the sleeve.  
       FIG. 3  shows a version of the connection of auxiliary lead (no. 3), which is connected by one end to connector P and by the other end to auxiliary pole P A .  
      Connector D is always connected to distal electrode E D  via lead no. 1 and lead P is connected to proximal electrode E P  via lead no. 2.  
      Thus the colinear coils have, in the two connection modes of  FIGS. 1 and 3 , a section which is common to the three leads between connector P and outlet point A of the branch connector, and a section common to the two leads between said output A and the electrodes of the pacing wire. Conversely, in the zone between connectors D and P, there are two leads (nos. 1 and 2) in  FIG. 1  for a single lead (no. 1) in  FIG. 3 .  
       FIG. 4  shows the branching of the wire routing the branching lead (output A) to auxiliary pacing pole P A . The branching is achieved at the junction of the cord of the wire to tip  2  for connection to the casing and is implemented by a sleeve  6  made of insulating material such as silicone.  
      The electrical connection between end A of auxiliary lead and pole P A  is implemented by a stripped spiral lead  7 , connected to end A by a connecting conductive plug  8  and covered by a silicone insulating sheath  9 .  
       FIG. 5  shows how auxiliary pole P A  is used. A conductive stylet  10  is inserted into pole P A  so as to come into contact with lead  7  of branch  11 . An alligator clip  12  for example is attached to stylet  10  and is electrically connected to an external pacemaker  5  (not shown).  
       FIG. 6  shows a first embodiment of auxiliary pole P A . The end of lead  7  is forcibly inserted at least partially into a sleeve  13  of electrically insulating material, which is itself partially inserted into a second sleeve  14  of electrically insulating material.  
      Sleeve  14  on one end includes a cylindrical housing  15  partially occupied by sleeve  13 , the remainder of the housing being occupied by a closure member  16  of silicone or the like. The other end of sleeve  15  defines a cylindrical housing  17  which holds a closure member  18  made of silicone or the like which is identical to closure member  16 .  
      Between two housings  15  and  17  a conduit  19  of reduced diameter is arranged coaxially to them.  
      Closure members  16  and  18  have a shape that facilitates the insertion of stylet  10  of  FIG. 5 .  
      Input closure member  18  has a central shell  21 , which is surrounded by a more massive annular part  22  that defines a cavity  23  with the shape of a truncated cone for guiding the insertion of stylet  10  in the direction of the central shell  21  having a diameter slightly greater than that of guide channel  19 . Shell  21  can be pre-perforated or pre-split.  
      Thus, the penetration of stylet  10  into connecting tip  14  is perfectly guided and the end of the stylet is perfectly centered on the axis of lead  7 .  
      Stylet  10  is fitted to the interior of the lead  7  over a certain distance and is kept perfectly stationary relative to the tip by the pressure of the material of the two closure members  16  and  18  that are traversed. Thus the physical contact between the stylet and the lead is guaranteed to be reliable and effective in electrical terms, while having an optimum seal at the level of tip  14  due to double closure members ( 16 ,  18 ).  
       FIGS. 7 and 8  show a second embodiment of auxiliary pole P A .  
      The end (auxiliary pole side) of branching lead  7  is shown at  24 .  
      This end  24  is soldered to a stainless steel wire  25  on which a likewise stainless steel tube  26  can slide, the latter itself mounted so as to be able to slide in an insulating sleeve  27  to which the insulating sheath  9  is welded.  
      Tube  26  can be actuated using a knob  28 , which is integral with tube  26 .  
      A wiper seal housed in a chamber  30  installed on the end of sleeve  27  is shown at  29  and an O-ring which is placed between tube  26  and knob  28  and which is able to slide into chamber  30  is shown at  31 . This device ensures the seal of the auxiliary pole when knob  28  is in the pushed-in position ( FIG. 7 ) which blocks chamber  30 .  
       FIG. 8  shows knob  28  in the output position, thus exposing the part of tube  26  on which alligator clip  12  of  FIG. 5  can be attached.  
      The invention is not limited to the illustrated example and can be applied especially to a pacing wire for which an adapter is inserted either between tip  2  and the casing of the pacemaker or between wire  1  and the implanted proximal and distal electrodes.