Patent Publication Number: US-2023144070-A1

Title: Connector of an implantable medical device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is the United States National Phase under 35 U.S.C. § 371 of PCT International Patent Application No. PCT/EP2021/059441, filed on Apr. 12, 2021, which claims the benefit of European Patent Application No. 20170571.2, filed on Apr. 21, 2020, the disclosures of which are hereby incorporated by reference herein in their entireties. 
    
    
     TECHNICAL FIELD 
     The present invention concerns a connector of an implantable medical device according to the preamble of claim  1 . 
     BACKGROUND 
     A connector of this kind is connectable to a mating connector of an assembly to be connected to the implantable medical device along an insertion direction. The connector comprises a contacting device for making electrical contact with an electrical contact element of the mating connector, wherein the contacting device comprises a housing and a contact spring arranged in the housing. 
     An implantable medical device may, for example, be formed by a pulse generator of a stimulation system, for example, a pacemaker or defibrillation system or a neuro-stimulation system. Such a pulse generator can, for example, be implanted subcutaneously into a patient, wherein electrodes are usually connectable to the pulse generator for implantation at a location of interest, for example, in the heart of a patient, in order to cause stimulation at the location of interest. 
     For connecting an assembly, for example, an electrode, to an implantable medical device, for example, a pulse generator, a connector is used which can be mated with an associated mating connector to establish an electrical connection between the assembly and the implantable medical device. Generally, high demands for such medical connectors for use on medical devices exist. Connectors should be biocompatible. In addition, connectors must be able to provide for a good electrical connection with high conductivity and low, essentially invariable electrical resistance. The connection of an assembly, for example, an electrode, to an implantable medical device should be simple and convenient, with a reliable and safe connection during operation. 
     Conventional connectors for use on implantable medical devices, such as known from U.S. Publication No. 2003/0157846 A1 or U.S. Publication No. 2005/0234521 A1, usually have a contacting device, in which a contact spring in the form of an annular helical spring is enclosed in a housing and is elastically deformable in such a way that a mating connector in the form of a contact pin can be inserted into an insertion opening formed by the housing and surrounded circumferentially by the contact spring in order to make contact with the housing via the contact spring. In U.S. Publication No. 2005/0234521 A1, herein, coil turns of the contact spring are arranged at a skewed angle, which allows the coil turns of the contact spring to slide in a scraping fashion along the mating connector when the mating connector is mated to the connector, in this way scraping off any oxide film potentially present on the mating connector to improve an electrical contact between the mating connector and the connector. Such contact springs are also referred to as canted coil springs. 
     To provide a biocompatible connector, a contact spring of a contacting device is made, for example, of a platinum or iridium material. Platinum or iridium usually has a low elasticity, which makes it necessary to form the contact spring such that it may be deformed within a range of elasticity, while allowing a repeated connection of a connector to a corresponding mating connector with a low risk of failure of the contact spring, especially when taking into account the usual sizes for medical connectors in the millimeter range. 
     The present disclosure is directed toward overcoming one or more of the above-mentioned problems, though not necessarily limited to embodiments that do. 
     SUMMARY 
     It is an objective of the instant invention to provide a connector of an implantable medical device that may provide for a reliable connection to an associated mating connector. 
     At least this objective is achieved by a connector comprising the features of claim  1 . 
     Accordingly, the contacting device forms a multiplicity of head sections for electrically contacting the electric contact element of the mating connector, a multiplicity of first foot sections electrically contacting the housing and a multiplicity of second foot sections electrically contacting the housing, the first foot sections being arranged at a first axial position and the second foot sections at a second axial position different than the first axial position, when viewed along the insertion direction. 
     The contact spring forms head sections for electrically contacting the electrical contact element of the mating connector. If the connector is mated with the mating connector along the insertion direction, the contact element of the mating connector comes into contact with the contact spring of the contacting device, such that an electrical contact in between the contact element of the mating connector and the contact spring is established. By means of its foot sections, herein, the contact spring is in abutment and hence in electrical contact with the housing of the contacting device, such that via the contact spring an electrical connection in between the contact element of the mating connector and the housing of the connector is established, once the connector is mated with the mating connector. 
     The shape of the contact spring herein diverts from the shape of a regular helically wound spring. In particular, the contact spring forms different foot sections, first foot sections being arranged at a first axial position and second foot sections being arranged at a second axial position, with reference to the insertion direction. The first foot sections and the second foot sections hence are axially displaced with respect to each other, such that a contacting abutment in between the contact spring and the housing of the contacting device is established via different foot sections at axially different positions. 
     The foot sections hence are placed at axially different positions. The foot sections herein, in one embodiment, may be joined with each other via the head sections, such that the contact spring may form an opening in between the first foot sections and the second foot sections, the contact spring extending within a surface of revolution, the surface having a U-shape or a horseshoe-shape in space and being rotated about a center axis to form the contact spring. 
     In one embodiment, the contact spring has a meandering shape. The contact spring may, for example, be formed by a continuous wire or may be cut from surface element, such as a planar plate element or a hollow tubing, the foot sections and the head sections being formed by adjoining, meandering sections of the contact spring. 
     In one embodiment, the contact spring extends along a direction of extension, wherein the head sections are aligned along the direction of extension. The direction of extension may, for example, extend longitudinally, the contact spring hence forming a longitudinal, straight element, particularly after forming of the contact spring but before assembly of contact spring and housing. In other words, a straight formed contact spring has to be formed in to an annular form before assembly with the housing. Alternatively, the direction of extension may be curved, for example, about a center axis, the contact spring hence forming a ring element which may be a circumferentially closed or may be circumferentially opened in that ends of the contact spring are not fixedly connected to each other. 
     In one embodiment, the head sections are aligned with each other along the direction of extension. The head sections hence are spaced with respect to each other along the direction of extension, wherein the head sections may be spaced at equal distances or at unequal distances. 
     In one embodiment, the first foot sections and the second foot sections alternate, when viewed along the direction of extension, a first foot section in each case being followed by a second foot section and vice versa. The first foot sections and the second foot sections thus are interleaved, when viewed along the direction of extension, a first foot section at its first axial position being followed by a second foot section at the second axial position, such that the foot sections are staggered along the direction of extension and in addition are axially displaced with respect to each other along the insertion direction. 
     In one embodiment, the head sections are curved about the direction of extension. Each head section herein may connect a first foot section at the first axial position to a second foot section at the second axial position, such that the first foot sections and the second foot sections are linked via the head sections, the head sections hence bridging the first foot sections at the first axial position on a first side of the contact spring and the second foot sections at the second axial position on a second side of the contact spring. Due to their curved shape, the head sections may come into abutment with a contact element of a mating connector once the mating connector is connected with the connector, such that an electrical contact in between the contact element of the mating connector and the contact spring and via the contact string to the housing may be established. 
     In one embodiment, the contact spring extends about the insertion opening, such that a contact element of a mating connector may be received radially within the contact spring for contacting with the head sections of the contact spring for establishing an electrical connection in between the mating connector and the contacting device of the connector. 
     Herein, the head sections beneficially face towards the center axis, such that the head sections may abut and hence electrically contact with the contact element of the mating connector once the mating connector is inserted into the insertion opening of the contacting device. 
     In one embodiment, each head section extends within an associated skewed plane which forms a skewed angle to the direction of extension. The head section may be curved within the skewed plane, wherein due to the orientation of the skewed plane the head section is arranged at a skewed angle with respect to the direction of extension of the contact spring and hence, if the contact spring extends circumferentially about a center axis and is formed by a surface of revolution, to a radial direction with respect to the center axis. Due to the skewed orientation of the head sections, the head sections may be tilted and thus radially moved under elastic tensioning of the contact spring when the mating connector is plugged into the connector, such that, when the connector is mated with the mating connector, the head sections are elastically tensioned by elastic deformation of the contact spring and thus bear with elastic tension against the contact element of the mating connector when the connector and the mating connector are mated with each other. 
     The skewed orientation of the head sections thus provides a defined elasticity at the contact spring. The inclined position of the head sections in addition allows achieving a beneficial contact between the head sections and the contact element of the mating connector. 
     In one embodiment, each of the first foot sections and/or each of the second foot sections are curved about an associated rotational axis which extends substantially along the insertion direction. The foot sections hence comprise a curvature, the curvature providing for a turn in a plane substantially perpendicular to the insertion direction. The foot sections herein may provide for a deformation zone in which the contact spring is elastically deformable when mating the connector with a corresponding mating connector, the foot sections hence defining a rotational axis for the head sections about which neighboring head sections may be tilted with respect to each other. Particularly, each foot section may act as a counter-bearing or common rotation axis for two neighboring head sections, particularly such that both head sections move substantially parallel when the mating connector is plugged into the connector. 
     Particularly, the whole contact spring, i.e., each part of contact spring including head and foot section, is configured to be deformed under elastic tensioning of the contact spring when the mating connector is plugged into the connector. 
     In one embodiment, each first foot section is joined via a first leg to one of the head sections and via a second leg to another of the head sections. The first foot sections hence are linked to adjoining head sections via legs, wherein the legs may, in one embodiment, be arranged such that they are not parallel with respect to each other. The legs may be arranged with respect to each other such that they extend from the associated foot section and are arranged at a skewed angle with respect to one another so that they approach one another (taper) towards the adjoining head sections. 
     The first leg and the second leg, for example, may be arranged in a common first plane which extends substantially perpendicular to the insertion direction. The first plane herein may be placed at the first axial position such that the legs are arranged at the same axial position as the first foot sections. 
     Alternatively or in addition, in one embodiment, each second foot section is joined via a third leg to one of the head sections and via a fourth leg to another of the head sections. 
     The second foot sections hence are linked to adjoining head sections via legs, wherein the legs may, in one embodiment, be arranged such that they are not parallel with respect to each other. The legs may be arranged with respect to each other such that they extend from the associated foot section and are arranged at a skewed angle with respect to one another so that they approach one another (taper) towards the adjoining head sections. 
     The third leg and the fourth leg, for example, may be arranged in a common second plane which extends substantially perpendicular to the insertion direction. The second plane herein may be placed at the second axial position such that the legs are arranged at the same axial position as the second foot sections. 
     The housing can be used, for example, to establish an electrical connection to an electrical assembly of the implantable medical device, for example, by connecting an electrical line to the housing. 
     A connector of the type described may be located on an implantable medical device in the form of a pulse generator of a stimulation system, for example, a pacemaker or defibrillation system or a neuro-stimulation system. Such a pulse generator can, for example, be implanted subcutaneously in a patient, wherein an electrical assembly can be connected to a pulse generator, for example, an electrode, which is to be implanted at a location of interest, for example, in the heart of a patient, in order to cause a stimulation at the location of interest. 
     Additional features, aspects, objects, advantages, and possible applications of the present disclosure will become apparent from a study of the exemplary embodiments and examples described below, in combination with the Figures and the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The idea underlying the present invention shall subsequently be explained in more detail with reference to the embodiments shown in the figures. Herein: 
         FIG.  1    shows a view of the human heart with an implanted stimulation system; 
         FIG.  2    shows a schematic view of a terminal block of a pulse generator of the stimulation system; 
         FIG.  3    shows a perspective view of an embodiment of a contacting device of a connector for electrically contacting with a contact element of a mating connector; 
         FIG.  4    shows a front view of the contacting device; 
         FIG.  5    shows a perspective view of a contact spring of the contacting device; 
         FIG.  6    shows a front view of the contact spring; 
         FIG.  7    shows a side view of the contact spring; 
         FIG.  8    shows a partially cut view of the contacting device; 
         FIG.  9 A  shows a front view of the contacting device, with a mating connector mated with the contacting device; 
         FIG.  9 B  shows a sectional view along line A-A as shown in  FIG.  9 A ; 
         FIG.  10    shows a view of a part for forming the contact spring, in an intermediate step during manufacturing; 
         FIG.  11    shows a view of the part of  FIG.  10   , after bending foot sections relative to head sections; 
         FIG.  12    shows a bottom view of the party according to  FIG.  11   ; 
         FIG.  13    shows a side view of the part according to  FIG.  11   ; 
         FIG.  14    shows a front view of the part according to  FIG.  11   ; 
         FIG.  15    shows a view of a part for forming the contact spring, in another embodiment; and 
         FIG.  16    shows a front view of the part according to  FIG.  15   . 
     
    
    
     DETAILED DESCRIPTION 
     In the following, embodiments of the instant invention are described with reference to the figures. In the figures, components having like functions are denoted using the same reference signs. 
     It shall be noted that the embodiments described herein are not to be understood as restrictive for the present invention, but merely serve the purpose of illustration. 
       FIG.  1    shows a schematic view of the heart H of a patient with an implanted stimulation system, for example, in the form of a so-called CRT system. The stimulation system  1  comprises a pulse generator  10  to which electrodes  11 ,  12 ,  13  are connected. The pulse generator  10  is implanted together with the electrodes  11 ,  12 ,  13  in the patient in such a way that the electrodes  11 ,  12 ,  13  extend from the pulse generator  10  through the upper vena cava V to the heart H and to different stimulation locations in the heart H. 
     In the example shown, three electrodes  11 ,  12 ,  13  are connected to the pulse generator  10 . The pulse generator  10 , for example, is implanted subcutaneously in the area of the patient&#39;s collarbone. From the pulse generator  10  the electrodes  11 ,  12 ,  13  extend in such a way that the electrodes  11 ,  12 ,  13  come to rest with their distal ends  110 ,  120 ,  130 , for example, in the right atrium RA (electrode  11  with the distal end  110 ), in the left ventricle LV (electrode  12  with the distal end  120 ) and in the right ventricle RV (electrode  13  with the distal end  130 ) and thus a stimulation may take place at different stimulation locations in the heart H via stimulation pulses generated by the pulse generator  10  and fed to the electrodes  11 ,  12 ,  13 . 
     In cardiac resynchronization therapy, for example, stimulation takes place in the left is ventricle LV and in the right ventricle RV, so that stimulation can bring about synchronicity of ventricular activity. In this way, the pumping capacity of the heart H is to be increased in patients with chronic cardiac insufficiency. 
     As schematically shown in an embodiment in  FIG.  2   , the pulse generator  10  has a housing  100  in which electrical and electronic components in the form of a control device  105  and a power supply device  106  in the form of a battery are enclosed and encapsulated. 
     A terminal block  101  is arranged on the housing  100  and has connectors  102 ,  103 ,  104  in the form of socket connectors, into which electrodes  11 ,  12 ,  13  with associated mating connectors  112 ,  122 ,  132  in the form of plugs can be inserted in order to establish an electrical connection between the electrodes  11 ,  12 ,  13  and the connectors  102 ,  103 ,  104  and thus the pulse generator  10 . 
     The connectors  102 ,  103 ,  104 , for example, are standardized and are designed as IS-1 or IS4 connections according to ISO 27186:2010. 
     The connectors  102 ,  103 ,  104  each have electrical contacting devices  2  for electrically contacting with contact elements  3  of mating connectors  112 ,  122 ,  132 , wherein a first connector  102 , for example, may have two contacting devices  2  and the other two connectors  103 ,  104  each may have four contacting devices  2 . The connector  102  is thus designed as a two-pole connection, while the other connectors  103 ,  104  are designed as four-pole connections. 
     Depending on the design of the connectors  102 ,  103 ,  104 , the mating connectors  112 ,  122 ,  132  of electrodes  11 ,  12 ,  13  are designed as IS-1 plugs (mating connector  112 ) or IS4 plugs (mating connectors  122 ,  132 ), for example, and have two electrical contact elements  3  (two-pole mating connector  112 ) or four electrical contact elements  3  (four-pole mating connectors  122 ,  132 ). 
     The contacting devices  2  of the connectors  102 ,  103 ,  104  and the contact elements  3  of the mating connectors  112 ,  122 ,  132  are designed in such a way that a pair-wise electrical contact is established between the respectively associated contacting devices  2  and contact elements  3  when the respective connector  102 ,  103 ,  104  and mating connector  112 ,  122 ,  132  are mated with each other. Each contacting device  2  thus serves to establish an electrical connection with an associated contact element  3  of a mating connector  112 ,  122 ,  132  when the mating connector  112 ,  122 ,  132  is mated with an associated connector  102 ,  103 ,  104 . 
       FIGS.  3  to  9 A,  9 B  show an embodiment of a contacting device  2  which has a substantially annular shape and forms an insertion opening  22  into which an associated mating connector  112 ,  122 ,  132  can be inserted along an insertion direction E, which is aligned with a center axis M concentric with the contacting device  2 , so that a contact element  3  arranged on the mating connector  112 ,  122 ,  132  comes to lie radially inside the contacting device  2 . 
     In the shown embodiment, the contacting device  2  comprises a housing  20  which receives a contact spring  21  for contacting with a contact element  3  of a mating connector  112 ,  122 ,  132 . The shape of the contact spring  21  diverts from the shape of a regular, helically wound spring in that it forms head sections  210  facing towards the center axing M of the contacting device  2  and foot sections  211 ,  212  placed radially outside of the head sections  210 , the foot sections  211 ,  212  being axially displaced along the center axis M with respect to one another. 
     While the head sections  210  facing radially inwards serve to contact with a contact element  3  of a mating connector  112 ,  122 ,  132  inserted along the insertion direction E into the contacting device  2 , as illustrated in  FIG.  3   , the contact spring  21  by means of the foot sections  211  abuts with the housing  20  and hence is in electrical contact with the housing  20 . 
     As visible from  FIG.  3    in view of  FIG.  8   , first foot sections  211  are arranged at a first axial side of a ring section  204  protruding radially inwards inside the housing  20 , and second foot sections  212  are arranged at a second side of the ring section  204 . The foot sections  211 ,  212  hence are axially displaced, wherein each foot section  211 ,  212  is in abutment with the housing  20  and hence electrically contacts the housing  20 . 
     As visible from  FIG.  3    in view of, for example,  FIG.  5    and  FIG.  8   , the contact spring  2  extends along a surface of revolution, the surface of revolution being formed by a U shape or a horseshoe shape which is revolved in space about the center axis M. In particular, the contact spring  21  extends along a surface which is opened at a side facing radially outwards. 
     Referring now to  FIG.  6   , the contact spring  21  extends along a direction of extension C, the direction of extension C being curved about the center axis M along a circle about the center axis M. The head sections  210  are aligned along the direction of extension C, wherein the head sections  210  are equally spaced with respect to each other and face radially inwards. 
     As visible from  FIG.  6    in view of  FIG.  5   , the head sections  210  are curved about the direction of extension C, such that the head sections  210  have a rounded shape. 
     Each head section  210  herein links a first foot section  211  at a first axial side of the contact spring  21  to a second foot section  212  at a second axial side of the contact spring  21 . Each foot section  211 ,  212  is curved about an associated axis of rotation A, the first foot sections  211  being arranged in a first plane P 1  at a first axial position, as illustrated in  FIG.  7   , and the second foot sections  212  being arranged within a second plane P 2  at a second axial position. The first foot sections  211  and the second foot sections  212  hence are axially displaced with respect to each other. 
     Because each foot section  211 ,  212  is curved about an associated axis of rotation A, it provides for a turn within the associated plane P 1 , P 2 . Each first foot section  211  herein, as visible from  FIG.  5   , via an associated pair of legs  213 ,  214  is linked to adjoining head sections  210 . Each second foot section  212  is joined to adjoining head sections  210  via an associated pair of legs  215 ,  216 . 
     As visible from  FIG.  6   , the legs  213 ,  214 ,  215 ,  216  of each pair of legs adjoining a foot section  211 ,  1212  do not extend in parallel to one another, but taper towards the head sections  210 . 
     As visible from  FIG.  5    in view of  FIG.  6   , the first foot sections  211  and the second foot sections  212 , in addition to being axially displaced along the center axis M, are staggered along the direction of extension C, such that each first foot section  211  at the first axial position is followed by a second foot section  212  at the second axial position, as in particular visible from  FIG.  6   . 
     In addition, as visible from  FIG.  6   , the head sections  210  each extend within a skewed plane B being arranged at a skewed angle α with respect to the direction of extension C and a radial direction R. Due to the skewed arrangement of the head sections  210  and the legs  213 ,  214 ,  215 ,  216  adjoining the head sections  210  at either axial side of the contact spring  21 , the head sections  210  may be elastically moved radially outwards when inserting a mating connector  112 ,  122 ,  132  into the insertion opening  22  formed by the contacting device  2 , such that the contact spring  21  is elastically deformed by bending the head sections  210  and the adjoining legs  213 ,  214 ,  215 ,  216  and the head sections  210  come to rest under elastic pretension on the contact element  3  of the mating connector  112 ,  122 ,  132 . 
     Due to the rounded shape of the head sections  210 , the head sections  210  may easily slide onto the contact elements  3  of the mating connector  112 ,  122 ,  132 , when inserting the mating connector  112 ,  122 ,  132  in the insertion direction E into the insertion opening  22  of the contacting device  2 . Due to the skewed arrangement of the head sections  210  and due to the elastic pretensioning forces caused by deformation of the contact spring  21  when inserting the mating connector  112 ,  122 ,  132 , the head sections  210  may scrape through an oxide layer potentially present on the contact element  3 , such that an electrical contact with the contact element  3  is improved. 
     Referring now to  FIG.  8   , the housing  20  is formed by a housing part  200  which is fixedly connected to a housing cover  201 . Herein, the housing part  200  forms, on a circumferential outer wall, the ring section  204  facing radially inwards. 
     For fabricating the contacting device  2 , the contact spring  21  is arranged within the housing part  200  prior to fixing the housing cover  201  to the housing part  200 , wherein after insertion of the contact spring  21  into the housing part  200  the housing cover  201  is arranged on the housing part  200  and is fixed to connected to the housing part  200 , for example, by gluing or welding. 
     The contact spring  21  may be formed from a continuous wire, which is bent to assume a meandering shape, as a visible, for example, from  FIG.  5   . The continuous wire herein may be circumferentially closed in that ends of the wire are connected to each other, wherein alternatively the continuous wire may be circumferentially opened in that the ends of the wire are not connected to each other. 
     In an alternative embodiment, as shown in  FIG.  10   , a part forming the contact spring  21  may be cut, for example, using laser cutting, from a plate-like element, such that in an intermediate state during fabrication a planar element is formed as shown in  FIG.  10   . By bending the foot sections  211 ,  212  with respect to the head sections  210 , as shown in FIGS.  11  to  14 , the contact spring  21  is formed, which prior to inserting it into the housing  20  extends straight along a longitudinal direction. 
     For placing the contact spring  21  on the housing  20 , the contact spring  21  may be bent such that the contact spring  21  assumes an annular shape, as visible from  FIGS.  3  to  9 A,  9 B , wherein prior to inserting the contact spring  21  into the housing  20  ends of the contact spring  21  may be fixedly connected to each other, or alternatively the ends may be left open such that the contact spring  21  is circumferentially opened. 
     In yet another embodiment, shown in  FIGS.  15  and  16   , the contact spring  21  may be cut, for example, using laser cutting, from a hollow tube element, such that after cutting the contact spring  21  extends straight along a longitudinal direction, as visible from  FIG.  15   . In this embodiment, legs linking the foot sections  211 ,  212  to the head sections  210  are curved, corresponding to the curvature of the hollow tube element from which the contact spring  21  is cut. 
     In either case, the contact spring  21  may, for example, be made from a platinum or iridium material to obtain a biocompatible connector  102 ,  103 ,  104 . 
     The idea underlying the present invention is not limited to the embodiments described above, but may be implemented in entirely different ways. 
     A connector of the type described herein can be used on an implantable medical device that is, for example, part of a stimulation system or another system. In general, a connector can be used, e.g., on a therapeutic system or on a diagnostic system, for example, a sensor system or a recording system, wherein such a connector can be used to provide for a connection for an electrode or another (electrical) assembly. 
     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, including the end points. 
     LIST OF REFERENCE NUMERALS 
     
         
           1  Stimulation system 
           10  Implantable medical device (pulse generator) 
           100  Housing 
           101  Terminal block 
           102 - 104  Connector 
           105  Controller 
           106  Energy supply device 
           11  Sub-assembly (electrode) 
           110  Distal end 
           111  Proximal end 
           112  Mating connector 
           12  Sub-assembly (electrode) 
           120  Distal end 
           121  Proximal end 
           122  Mating connector 
           13  Sub-assembly (electrode) 
           130  Distal end 
           131  Proximal end 
           132  Mating connector 
           2  Contacting device 
           20  Housing 
           200  Housing part 
           201  Housing cover 
           202 ,  203  Side wall 
           204  Ring section 
           21  Contact spring 
           210  Head sections 
           211 ,  212  Foot sections 
           213 - 216  Legs 
           22  Insertion opening 
           3  Electrical contact element 
         α Skewed angle 
         A Rotational axis 
         B Skewed plane 
         C Direction of extension 
         E Insertion direction 
         H Heart 
         LA Left atrium 
         LV Left ventricle 
         M Center axis 
         P 1 , P 2  Plane 
         R Radial direction 
         RA Right atrium 
         RV Right ventricle 
         V Upper vena cava