Abstract:
A conductive coil arrangement, in particular for electrode catheters for cardiac therapy, including a multipolar conductive coil having a plurality of coradially interwoven individual coil wires and a contact zone in which at least one individual coil wire from the conductive coil can be connected to a contact element for electrical contacting. The at least one individual coil wire to be contacted is routed outwardly out of the wire interconnection of the conductive coil with a radial direction component. The remainder of the conductive coil is routed further centrally axially through the contact zone.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application claims the benefit of co-pending U.S. Provisional Patent Application No. 61/569,797, filed on Dec. 13, 2011, which is hereby incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a conductive coil arrangement, in particular for electrode catheters for cardiac therapy, comprising a multipolar conductive coil having a plurality of coradially interwoven individual coil wires, and a contact zone in which at least one individual coil wire from the conductive coil can be connected to a contact element for electrical contacting. The present invention furthermore relates to an electrode catheter device in which such a conductive coil arrangement is used. 
     BACKGROUND 
     Regarding the background of the invention, it should be noted that a complex, rigid mechanism has been used over a long distance, as is known, to electrically and mechanically connect the individual coil wires of coradial, multipolar conductive coils. An example thereof is a connection of individual coil wires to a ring electrode of an electrode catheter, as shown in an older application published under U.S. Publication No. 2012/0053668, with simultaneous passage of a single coil wire through said ring electrode. 
     Furthermore, electrode supply leads having a so-called multiple-lumen design are known, wherein the supply leads are designed as so-called cords. They are connected to a multipolar plug, such as the type used by the Applicant herein, as known, having the name “DF-4”. The electrode catheters are based on a multiple-lumen tube which guides electrically conductive cords or coils from the top electrodes and ring electrodes to the connecting plug in a plurality of axes extending parallel to the longitudinal axis of the tube. The contact ends of the cords or coils, which extend toward one another, and the contact elements in the plug have an axial orientation with respect to one another, and are therefore relatively easily accessible for a related electrical connection. 
     The connection of conductive coils to components to be contacted has previously been carried out preferably by placing the particular coil end or individual wires on shoulders or projections of contact sleeves, wherein the electrical connection is achieved by way of form-fitting or bonding methods such as, for example, crimping, welding, soldering, etc. It is also known to weld the coil in a bore extending through the sleeve. According to a further known connection type—preferably for non-weldable material combinations—the coil end is connected between two sleeves, by way of crimping, for example. The structure comprises a lower sleeve (rigid), contact wires located there between, and a crimping sleeve over it, which is plastically deformed to achieve a form-fit connection and, therefore, an electrical contact. This connection principle also functions with individual wires or cords. In this case, a coil is not located between the sleeves and, instead, radially or axially incoming wires or cords, which extend out of the coil connection of the catheter body, are folded and/or deformed to fit. Likewise, it is possible to insert these individual wires or cords into bores or sleeves for contacting, and to connect them in a bonded or form-fit manner (e.g., by welding or crimping). 
     The usability of these usual techniques for the connection of coil wires is limited in many regards, in particular with regard to the connection of the individual coil wires of coradial multiple coils at axially extending contact elements of plugs. 
     Proceeding from the problems of the prior art mentioned above, an objective of the present invention is to improve a conductive coil arrangement of the initially stated type in such a way that a structurally simple, universally applicable connection to contact elements of highly diverse types is made possible. 
     The present invention is directed toward overcoming one or more of the above-identified problems. 
     SUMMARY 
     A problem is solved according to a rough, basic concept in that the at least one individual coil wire of the multipolar conductive coil, which is to be contacted, is routed outwardly out of the wire interconnection of the conductive coil using a radial directional component, and the remainder of the conductive coil is routed further centrally axially through the contact zone. 
     Due to this design according to the present invention, a coradial coil is therefore transformed into radially offset individual coil wires which can then be better contacted. This separation is possible for an arbitrary number of conductors from the multipolar interconnection of coradial conductive coils. 
     According to a preferred embodiment of the present invention, the conductive coil, which is routed centrally axially further through the contact zone, is an individual coil wire, wherein the remaining, radially outwardly extending individual coil wires of the conductive coil are each in the form of individual contact coils which are disposed axially parallel and are preferably distributed equidistantly around the periphery. The latter can also have a smaller outer diameter relative to the outer diameter of the conductive coil, in a preferred manner. 
     The preferred embodiments noted above have an advantage that the typical properties of a coil, such as, for example, elasticity and insensitivity to fluctuations in bending stress, can be retained in a short installation space. By way of the reduction of the outwardly extending individual contact coils, the total outer diameter of the conductive coil arrangement can be reduced significantly in the region of the contact zones. 
     According to a development of the present invention related to the outwardly extending individual coils, contact pins inserted coaxially therein are provided as contact elements for the electrical connection of the particular individual coil wires. Since the contact pins are then positioned in the axially parallel direction, they can be easily coupled to cooperating contact elements of a connecting plug for the conductive coil arrangement. 
     The above-mentioned basic concept of the conductive coil arrangement according to the present invention can also be developed further, according to an alternative embodiment, in such a way that the conductive coil routed centrally axially through the contact zone comprises an individual coil wire, although, in deviation from the above-mentioned variant, the remaining individual coil wires of the conductive coil are disposed with the ends thereof projecting radially, each being connected to a contact element. Contact blocks or contact sleeves can be used for the latter. In association with contact blocks, the ends of the individual coil wires can each be inserted into respective connection bores or contact blocks in the radial direction or offset in the peripheral direction, where they are preferably secured by way of, for example, crimping, welding and/or soldering. When contact sleeves are used, contacting can take place by way of wall slots in the sleeve walls by inserting the ends of the wires therein the radial direction and securing them using typical contact fixing techniques. This measure is a structurally, particularly simple, reliable, and extremely compact variant for the separation of coil wires of the coradial conductive coil and the contacting thereof. 
     According to a further development of the subject matter of the present invention, the contact elements, such as the individual coil wires, contact blocks and/or sleeves, are distributed equidistantly around the circumference of the conductive coil arrangement in a common axial position which therefore overlaps at least partially. This arrangement permits a space-saving electrical connection of the conductive coil across a short axial length and a small diameter since the individual coil wires are contacted in the same axial plane region. 
     Further preferred embodiments of the present invention relate to the connection of the conductive coil arrangement to further-extending connection elements, such as plugs. For example, a so-called terminal block is provided in the contact zone, in or at which the contact elements of the individual coil wires are secured. This terminal block is a defined transition piece from the conductive coil arrangement to a multipolar plug connection element, wherein the contact elements of the individual coil wires secured in the terminal block are disposed in the plug connection element in accordance with the positions of the contact poles. The contacting of the individual coil wires of the conductive coil therefore takes place in a particularly efficient manner, since the contact elements can be positioned in accordance with the requirements of the particular plug connection unit. Alternatively, additional electrical contact elements, which are connected to the contact members of the individual coil wires, can also be disposed in the terminal block. These contact elements are then coupled to the particular plug element in an electrode catheter arrangement. 
     The various concepts of a conductive coil arrangement explained above can be implemented advantageously in an electrode catheter arrangement, the basic configuration of which comprises an elongated, tube-type catheter body. With the aid of the conductive coil arrangement according to the present invention, by using a corresponding terminal block, a plug which is known per se, such as, for example, a stated DF4/IS4 plug having axially disposed contacts, can be connected and, therefore electrically connected, to individual coil wires incoming radially out of the interconnection of the conductive coil. The plug element can therefore be multipolar in design, preferably having at least four poles. The coradial conductive coil can then comprise individual coil wires in an appropriate number, preferably four, interwoven in a coradial manner. 
     According to a particularly preferred embodiment, the conductive coil and the terminal block can undergo final assembly as a prefabricated module with the plug element. 
     The plug and the incoming electrical leads can therefore withstand tensile forces and can be interconnected electrically and mechanically in a manner that is insensitive to fluctuating bending stress. This takes place in minimal installation space, wherein an individual or multiple coil wire can also be guided centrally axially through the contact zone. The terminal block can therefore serve simultaneously with the central guide opening, which is also provided, to route a mandrel or guide wire, which are used as an implantation aid in the implantation of the electrode catheter. 
     In summary, the present invention and the preferred variants thereof provide a large number of advantages over the prior art, some of which are listed below as a summary:
         The basic use of the coradial coil technique over cords avoids the problem of damage caused by forces and relative motions, in particular in the connection region at a plug.   Coil wires have better fluctuating bending stress properties than cords, and are better able to withstand tensile forces. It is therefore possible to avoid complex, coiled transfer pieces for relieving the tensile load on the cords.   Compared to cords, a conductive coil has better stability against radially acting forces, such as, for example, pinching at the catheter head.   Contact transfer within a very small installation space, as defined by the DF4/IS4 plug standard, for example, can therefore be achieved between a plug element and the conductive coil arrangement.   A type of modular system can be constructed in that the conductive coil arrangement having a corresponding terminal block forms a module that can be combined with a corresponding plug element as another module.       

     Further features, aspects, objects, advantages, and possible applications of the present invention will become apparent from a study of the exemplary embodiments and examples described below, in combination with the figures, and the appended claims. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       Further features, details, and advantages of the present invention will become apparent from the description of exemplary embodiments, which follows, and with reference to the attached drawings. The figures show: 
         FIG. 1  shows a perspective view of a conductive coil arrangement in a first embodiment; 
         FIGS. 2-4  show perspective views of a conductive coil arrangement having a plug element coupled thereto, in a second embodiment in basic degrees of cut-out; 
         FIGS. 5-6  show a perspective view of a conductive coil arrangement having a connected plug element in a third and fourth embodiment; 
         FIG. 7  shows a perspective view of a conductive coil arrangement comprising a terminal block; 
         FIG. 8  shows the arrangement according to  FIG. 7 , comprising a cover cap; 
         FIG. 9  shows an axial section of the arrangement according to  FIG. 8 , with plug element attached; and 
         FIGS. 10-11  show perspective views of the arrangement according to  FIG. 9 , from two different viewing angles in the preassembled state. 
     
    
    
     DETAILED DESCRIPTION 
     The conductive coil arrangement shown in  FIG. 1  comprises a four-poled, coradial conductive coil  1  in which the four individual coil wires  2 . 1  to  2 . 4  are interwoven coradially as a unit, i.e., in the manner of a four-turn thread. The conductive coil  1  terminates in a contact zone, labelled in entirety with reference number  3 , in which the individual coil wires  2 . 1  to  2 . 4  are connected to corresponding contact elements in a manner to be explained in greater detail hereafter. 
     In the contact zone  3 , one individual coil wire  2 . 1  is routed further centrally axially through the contact zone  3  without the pitch of the coil winding or the diameter thereof being changed. The remaining three individual coil wires  2 . 2  to  2 . 4  are released from the coil interconnection and are routed outwardly with equal offset of 120° in the peripheral direction at a slant relative to one another, i.e., with a radial directional component and an axial directional component. The stripped ends  4  of the individual coil wires  2 . 1  to  2 . 4  are wound, as individual contact coils, with a diameter a which is markedly smaller than the outer diameter A of the conductive coil arrangement, to form a contact coil  5 , all being oriented in the axially parallel direction. As contact elements for the electrical contacting of the individual coil wires  2 . 2  to  2 . 4 , coaxial contact pins  6  are inserted and mechanically fixed into the contact coils  5  thereof. The latter can be achieved in a structurally simple manner by the spring force of the contact coils  5  and a corresponding oversize of the contact pin  6  relative to the inner diameter of the contact coils  5 . An additional fixation with the aid of a soldering or welding point or the like, for example, can also be provided for safety reasons. The contact pins  6  can be connected in the axial direction using the contact elements, which are not depicted in greater detail herein, of a plug element, for example, and the conductive coil arrangement can therefore be connected to a plug element. 
       FIGS. 2-4  show, in various basic degrees of cut-out, a further embodiment of a conductive coil arrangement in which the conductive coil  1  is connected to a plug element  7 . As shown clearly in  FIG. 2 , the one individual coil wire  2 . 1  is guided further coaxially and, although, in contrast to the embodiment according to  FIG. 1 , is wound as a unit in the further section and is stripped at the end  8  thereof. 
     The remaining individual coil wires  2 . 2  to  2 . 4  are shortened and moved away from the conductive coil  1 , projecting outwardly in the radial direction. Due to the perspective view, only the two ends  4  of the individual coil wires  2 . 3  and  2 . 4  are visible in  FIGS. 2-3 . 
     The conductive coil  1  widened in this manner is then provided with an insulating tube  9  which terminates before the stripped end  8  of the central individual coil wire  2 . 1 . The stripped ends  4  of the remaining individual coil wires  2 . 2  to  2 . 4  project in the radial direction outwardly through the insulating tube  9 . 
     As shown in  FIG. 4 , elongated, cuboid contact blocks  10  are inserted onto these stripped ends  4 , and are mechanically and electrically connected to the ends  4  using typical contact connection measures of joining technology, such as, for example, crimping, welding, soldering, and the like. The contact blocks  10  comprise bores  11  which extend axially parallel, and into which contact pins of the plug element  7  are inserted and can be connected mechanically and electrically to the contact blocks  10  by way of the usual joining methods mentioned above. 
     The central individual coil wire  2 . 1  is inserted into a corresponding receptacle  12  of the plug element  7  and is likewise connected there mechanically and electrically to a central contact pole of the plug element  7  in a suitable manner. 
     Due to the flexibility of the conductive coil, the transition to the plug element  7  shown can be achieved in a manner that transfers tensile force, is insensitive to fluctuating bending stress, and is compact. 
       FIG. 5  shows a detailed variant of the embodiment according to  FIG. 4 . In this case, the radially projecting ends  4  of the individual coil wires  2 . 2  to  2 . 4  are inserted laterally with an offset  13  in the peripheral direction into a corresponding receiving hole  14  in the contact blocks  10  and are fixed therein. For the rest, reference is made to the description of  FIG. 4  with regard to the contact blocks  10  and the connection thereto to the plug element  7 . 
     A further alternative embodiment of the connection of a plug element  7  to a conductive coil  1  is shown in  FIG. 6 . The conductive coil  1  comprises four individual coil wires  2 . 1  to  2 . 4  which are prepared in a manner analogous to the intermediate production steps shown in  FIGS. 2 and 3 . Reference can be made to the description therein this regard. 
     In this embodiment according to  FIG. 6 , the radially projecting ends  4  of the individual coil wires  2 . 2  to  2 . 4  are fastened in contact sleeves  15  which, in turn, are disposed axially parallel equidistantly in the circumferential direction. The connection between the stripped ends  4  of the individual coil wires  2 . 2  to  2 . 4  with the contact sleeves  15  takes place by way of slots  17  formed in the end-face edges  16  of the contact sleeves  15  in a longitudinal axial plane, in which the ends  4  can be fastened once more by way of the joining methods mentioned above. 
     The contact sleeves  15  are electrically and mechanically connected to the corresponding contact poles of the plug element  7 . In the same manner, the central individual coil wire  2 . 1  is coupled by way of a receptacle  12  to the plug element  7  and is connected to a central pole thereof. 
       FIG. 7  shows an exemplary embodiment of a conductive coil arrangement, in which the contact elements in the form of contact sleeves  15 , which are connected as in  FIG. 6 , of the radially outwardly extending individual coil wires  2 . 2  to  2 . 4  and the central receptacle  12  for the central individual coil wire  2 . 1  are fixed in a terminal block  18 . The latter is made of an insulating material and corresponds by way of the cylindrical shape thereof—as shown herein—in the outer diameter to a plug element  7  via which the terminal block  18  is coupled to the plug element  7  mechanically and, via the contact elements, electrically to the plug element  7 , as shown in  FIG. 9  and as explained in greater detail below. 
       FIG. 8  shows the conductive coil  1  with terminal block  18  according to  FIG. 7 , wherein one more insulating cover cap  19  encloses the space in which the slots  17  in the contact sleeves  15  are disposed with the stripped ends  4  of the individual coil wires  2 . 2  to  2 . 4 . These contact points are therefore mechanically protected and electrically insulated to the outside. 
     The above-mentioned embodiment illustrated in  FIG. 9  shows the conductive coil arrangement comprising the conductive coil  1  and the terminal block  18  with the cover cap  19  in a configuration assembled together with the plug element  7 . The plug element  7  comprises contact pins  20 , which are aligned axially with the contact sleeves  15 , for the particular plug pole, which are inserted into the inner opening  21  of the contact sleeves  15  and are mechanically and electrically connected therewith. The central individual coil wire  2 . 1  is mechanically and electrically connected by way of the stripped end thereof to the central contact pole  22 . The overall result is a connection of the four-pole conductive coil  1  to a plug element having one central pole and three axially parallel contact poles  22  distributed equidistantly in the peripheral direction, only one of which is visible in  FIG. 9 , with the associated contact sleeve  15 . It is furthermore pointed out that the terminal block is provided with a centrally continuous guide opening  24  for a guide wire or a mandrel as an implantation aid. 
       FIGS. 10-11  explicitly show that the conductive coil  1  can be preassembled with a corresponding insulating tube  9  and a terminal block  18  as a modular assembly, just like the plug element  7  with three contact pins  20  thereof and the central contact pole  22 . The final assembly takes place simply by inserting the plug element  7  into the terminal block  18  of the conductive coil  1  with mechanical and electrical connection to the contact sleeves  15 . 
     One more variant is shown in  FIG. 11  with regard to the contact connection between the central contact pole  22  of the plug element  7  and the central individual coil wire  2 . 1 . The latter is provided with a contact pin  23  on the end  8  thereof, which can be connected to the contact pole  22  in a structurally particularly simple manner by way of mutual insertion. 
     It will be apparent to those skilled in the art that numerous modifications and variations of the described examples and embodiments are possible in light of the above teachings of the disclosure. The disclosed examples and embodiments are presented for purposes of illustration only. Other alternate embodiments may include some or all of the features disclosed herein. Therefore, it is the intent to cover all such modifications and alternate embodiments as may come within the true scope of this invention, which is to be given the full breadth thereof. Additionally, the disclosure of a range of values is a disclosure of every numerical value within that range.