Patent Publication Number: US-2023140572-A1

Title: Rotatable lead connectors

Description:
RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application Ser. No. 63/263,502, filed Nov. 3, 2021, the entire contents of each of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     This disclosure generally relates to medical devices, and more specifically, testing implantable medical leads during implantation procedures. 
     BACKGROUND 
     Various types of implantable medical leads have been implanted for treating or monitoring one or more conditions of a patient. Such implantable medical leads may be adapted to allow medical devices to monitor or treat conditions or functions relating to heart, muscle, nerve, brain, stomach endocrine organs or other organs and their related functions. Implantable medical leads include electrodes and/or other elements for physiological sensing and/or therapy delivery. Implantable medical leads allow the sensing/therapy elements to be positioned at one or more target locations for those functions, while the medical devices electrically coupled to those elements via the leads are at different locations. 
     Implantable medical leads may be implanted at target locations selected to detect a physiological condition of the patient and/or deliver one or more therapies. For example, implantable medical leads may be delivered to locations within an atria or ventricle to sense intrinsic cardiac signals and deliver pacing or antitachyarrhythmia shock therapy from a medical device coupled to the lead. In other examples, implantable medical leads may be tunneled to locations adjacent a spinal cord or other nerves for delivering pain therapy from a medical device coupled to the lead. Implantable medical leads may include anchoring components to secure a distal end of the lead at the target location. 
     SUMMARY 
     In general, this disclosure is directed to devices and techniques that facilitate guiding a distal electrode fixation of an implantable medical lead, e.g., in situ or in real time, to a desired position on and/or depth within tissue, e.g., position on the endocardial surface or depth within cardiac tissue, such as the intraventricular septum, or other cardiac tissue. Electrical signals, e.g., real-time electrical signals, sensed via the distal electrode, such as pacing impedance, signals indicative of pacing capture, or electrogram signals, may be used to determine whether a current position/depth is adequate. In the case of the His-Purkinje conduction system (HPCS), for example, the presence of HPCS features (e.g., features indicative of the electrical activity of the HPCS) in the cardiac electrogram may indicate an adequate distal electrode position. 
     In some cases, the whole implantable medical lead or a portion thereof is rotated during the implantation procedure. However, a test device used to collect signals from the distal electrode and its associated cabling may not be configured to rotate with the lead. For example, rotation of the lead may cause the cabling of the test device to become tangled, potentially interfering with the implantation procedure. 
     An implantable medical lead according to this disclosure may be configured such that different portions of the implantable medical lead are rotatable relative to one another. For example, the implantable medical lead may include a rotational electrical coupling configured to allow electrical communication between the test device and an electrode of the implantable medical lead during rotation. The rotational electrical coupling may comprise a first conductive component configured to be electrically connected to the electrode, and a second conductive component configured to be electrically connected to the test device. The rotational electrical coupling is configured to facilitate rotation of the first conductive component relative to the second conductive component. In this manner, an implantable medical lead according to this disclosure may allow a test device to remain connected to a portion of the rotational electrical coupling (e.g., the second conductive component) while implanting/fixing the lead by rotating the lead body without cables associated with the test device becoming tangled. In some examples, one or both of the first and second conductive components is included as part of a lead electrical connector configured to couple the implantable medical lead to an implantable medical device (e.g., an IS-1 connector). 
     In some cases, rotation of the medical lead (e.g., to advance the distal electrode into tissue) may introduce artifacts or other noise into these signals used to determine whether its position/depth is adequate. For example, relative rotation of portions of a conductive path between the electrode and the test device may introduce such noise, e.g., due to make/break events occurring during the relative rotation. The noise may corrupt the signals such that the adequacy of the position/depth of the electrode cannot be determined during rotation. Consequently, the implanting physician may need to frequently stop rotating to test a position before resuming rotation, which may increase the time and effort needed for the implantation procedure. 
     A lead according to the present disclosure may include features to maintain an electrical connection between the first and second conductive components during rotation of the implantable medical lead and, in some examples, to reduce the presence of noise in signals sensed by the distal electrode. For example, the rotational electrical coupling may include an elastically deformable element, such as a spring, beams, or fingers, configured to maintain the second conductive component in abutment and electrical contact with the first conductive component as the medical lead moves during rotation. These features may allow an implanting physician to observe electrical signals, or data derived therefrom, during rotation of the implantable medical lead, which may reduce the time and effort needed to identify an adequate implant position/depth for the distal electrode. 
     In some examples, an implantable medical lead comprises: a lead body extending from a proximal portion of the implantable medical lead to a distal portion of the implantable medical lead; an electrode at the distal portion of the implantable medical lead; and a lead electrical connector at the proximal portion of the implantable medical lead, wherein the lead electrical connector is configured to establish electrical communication between a test device and the electrode; and a rotational electrical coupling, wherein at least a portion of the rotational electrical coupling is mechanically supported by the lead electrical connector, and wherein the rotational electrical coupling comprises: a first conductive component electrically connected to the electrode; and a second conductive component electrically connected to the first conductive component, wherein the second conductive component is configured to establish electrical communication with the test device, and wherein the first conductive component and the second conductive component are configured to rotate relative to each other. 
     In some examples, a system comprises: a medical device; a test device; an implantable medical lead electrically connected to the medical device, the implantable medical lead comprising: a lead body extending from a proximal portion of the implantable medical lead to a distal portion of the implantable medical lead; an electrode at the distal portion of the implantable medical lead; and a lead electrical connector at the proximal portion of the implantable medical lead, wherein the lead electrical connector is configured to establish electrical communication between the test device and the electrode; and a rotational electrical coupling, wherein at least a portion of the rotational electrical coupling is mechanically supported by the lead electrical connector, and wherein the rotational electrical coupling comprises: a first conductive component electrically connected to the electrode; and a second conductive component electrically connected to the first conductive component, wherein the second conductive component is configured to establish electrical communication with the test device, and wherein the first conductive component and the second conductive component are configured to rotate relative to each other. 
     In some examples, a method comprises: rotating, by an implantable medical lead, to advance an electrode, for implantation in patient tissue, of the implantable medical lead, wherein the implantable medical lead comprises: a lead body extending from a proximal portion of the implantable medical lead to a distal portion of the implantable medical lead; an electrode at the distal portion of the implantable medical lead; and a lead electrical connector at the proximal portion of the implantable medical lead, wherein the lead electrical connector is configured to establish electrical communication between a test device and the electrode; and a rotational electrical coupling, wherein at least a portion of the rotational electrical coupling is mechanically supported by the lead electrical connector, and wherein the rotational electrical coupling comprises: a first conductive component electrically connected to the electrode; and a second conductive component electrically connected to the first conductive component, wherein the second conductive component is configured to establish electrical communication with the test device, and first conductive component and the second conductive component are configured to rotate relative to each other; and receiving, by the test device, signals sensed via the electrode during the rotation of the implantable medical lead. 
     The summary is intended to provide an overview of the subject matter described in this disclosure. It is not intended to provide an exclusive or exhaustive explanation of the systems, device, and methods described in detail within the accompanying drawings and description below. Further details of one or more examples of this disclosure are set forth in the accompanying drawings and in the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a conceptual diagram illustrating an example medical device system, including an example implantable medical lead, for delivering conduction system pacing to a patient. 
         FIG.  2    is a conceptual diagram illustrating an example system for testing the implantable medical lead of  FIG.  1    during an implantation procedure, the example system including a rotational electrical coupling to connect the implantable medical lead to a test device. 
         FIG.  3    is a cross-sectional diagram illustrating an example rotational electrical coupling. 
         FIG.  4    is a conceptual diagram illustrating another example rotational electrical coupling. 
         FIG.  5    is a cross-sectional diagram illustrating yet another example rotational electrical coupling. 
         FIG.  6    is a flow diagram illustrating an example technique for testing an implantable medical lead during an implantation procedure using a rotational electrical coupling. 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1    is a conceptual diagram illustrating an example medical device system  10  for delivering HPCS pacing to a heart  12  of a patient  14 . As illustrated by example system  10  in  FIG.  1   , system  10  may include an implantable medical device (IMD)  16  with cardiac pacing capabilities. IMD  16  is connected to an implantable medical lead  22  (“lead  22 ”) that includes a lead body  23  extending from a proximal portion  24  of lead  22  (“lead proximal portion  24 ”) to a distal portion  27  of lead  22  (“lead distal portion  27 ”). Lead proximal portion  24  may be operably coupled to IMD  16 . Although primarily described herein with respect to HPCS, the techniques of this disclosure may be applied to other regions of the heart, such as a left bundle branch (LBB) or a right bundle branch (RBB). Furthermore, although primarily described herein in the context of cardiac pacing, the techniques of this disclosure may be applied to non-cardiac contexts, such as neurostimulation. 
     IMD  16  senses electrical signals attendant to the depolarization and repolarization of heart  12 , e.g., a cardiac EGM, via electrodes on lead  22  and/or the housing of IMD  16 . IMD  16  may also deliver therapy in the form of electrical signals, e.g., cardiac pacing, to heart  12  via electrodes located on lead  22 . In the illustrated example, lead  22  includes a distal electrode  25 A at lead distal portion  27  and a proximal electrode  25 B located proximally of distal electrode  25 A (collectively, “electrodes  25 ”). In other examples, lead  22  may include more or fewer electrodes  25 , such as examples in which lead  22  includes only electrode  25 A. In some cases, lead  22  may include one or more sensors  21  at distal portion  27 . 
     Lead  22  extends into heart  12  of patient  14  to sense electrical activity of heart  12  and/or deliver electrical stimulation to heart  12 . In the example shown in  FIG.  1   , lead  22  extends through one or more veins (not shown), the superior vena cava (not shown), and right atrium  26 , and into right ventricle  28 . System  10  may include additional leads coupled to IMD  16 , such as a left ventricular (LV) lead that extends through one or more veins, the vena cava, right atrium  26 , and into the coronary sinus to a region adjacent to the free wall of left ventricle  32  of heart  12 , and/or a lead that extends into right atrium  26 . 
     Lead  22 , e.g., distal electrode  25 A, is positioned to provide pacing to the HPCS. Providing HPCS pacing is sometimes referred to as “His-Purkinje pacing.” In the illustrated example, lead  22  is positioned to provide pacing to His-Purkinje  20  between an atrioventricular bundle (not shown) and branches of Purkinje fibers  30 . In other examples, lead  22  and distal electrode  25 A may be implanted at positions to provide pacing to other portions of the HPCS, such as the LBB or RBB. 
     Distal electrode  25 A may be carried by a distal end of lead  22 . In addition to being electrically active, distal electrode  25 A may be configured to grasp tissues at or near a target site and substantially secure a distal end of lead  22  to the target site. In other words, distal electrode  25 A may be configured to substantially maintain an orientation of lead  22  with respect to the target site by penetrating tissue. Distal electrode  25 A may include one or more fixation tines of any shape, including, but not limited to, helically shaped fixation tines. For example, distal electrode  25 A may take the form of a fixed helix, a tine tip electrode, etc. 
     Electrode  25 B may take the form of a ring electrode electrically insulated from electrode  25 A. In some examples, distal electrode  25 A may be positioned within the cardiac tissue such that pacing stimulation delivered via distal electrode  25 A activates the HPCS. During an implantation procedure for lead  22 , an implanting physician may position a distal end of lead  22  at a desired location, and fix distal electrode  25 A distally from the distal end of lead  22  to a desired depth within the cardiac tissue, e.g., the intraventricular myocardium. 
     Lead  22  includes a lead electrical connector  29  (sometimes referred to herein as “connector  29 ” or “lead connector  29 ”), such as an IS-1 connector, configured to establish electrical communication between IMD  16  and electrodes  25 . Connector  29  is configured to electrically communicate with circuitry of IMD  16 . Connector  29  includes one or more conductors (not shown) configured to electrically communicate with electrodes  25 . In some examples, each of electrodes  25 A and  25 B is electrically coupled to a respective conductor within connector  29  and thereby coupled to circuitry within IMD  16 . In examples, connector  29  is configured such that electrical communication with distal electrode  25 A and proximal electrode  25 B occurs substantially independently to, e.g., facilitate correct placement of electrodes  25  and/or obtain a better electrical signal (lower threshold, lower impedance, etc.). 
       FIG.  2    is a conceptual diagram illustrating an example system  40  for testing lead  22  during an implantation procedure. As illustrated by the example of  FIG.  2   , system  40  includes a test device  44  that is connected to lead  22  via a cable  46 . More particularly, cable  46  includes a distal cable connector  42 , e.g., an alligator clip, configured to selectively physically and electrically connect cable  46  to lead connector  29 , although other selective or permanent connections between test device  44  and lead connector  29  are possible. System  40  also includes an auxiliary electrode  48 , which may be attached externally to patient  14 , e.g., via an adhesive patch. Auxiliary electrode  48  may be connected to test device  44  via a cable  50 . 
     As illustrated in  FIG.  2   , lead  22  includes a rotational electrical coupling  51  (sometimes referred to herein as “coupling  51 ”), which may be partially or wholly within lead connector  29 . Rotational electrical coupling  51  is configured such that different portions of lead  22  are rotatable relative to one another, while providing an electrical connection between test device  44  and distal electrode  25 A. Rotational electrical coupling  51  may comprise a first conductive component configured to be electrically connected to distal electrode  25 A, and a second conductive component configured to be electrically connected to test device  44 . The first conductive component and the second conductive component may be configured to rotate relative to each other. 
     Lead  22  may include a conductor  52  electrically connected to distal electrode  25 A and a conductor  54  electrically connected to proximal electrode  25 B. As will be discussed in greater detail below, conductor  52  is electrically connected to rotational electrical coupling  51 . Cable  46  includes a conductor  56  which is electrically connected or connectable to both rotational electrical coupling  51  and lead connector  29  via cable connector  42 , and test device  44 . When lead  22 , coupling  51 , cable  46 , and test device  44  are connected, conductors  52  and  56  electrically connect distal electrode  25 A to test device  44 . Auxiliary electrode  48  is also connected or connectable to test device  44  via a conductor  58  of cable  50 . In the illustrated example, coupling  51  via cable  46  is configured to electrically connect one electrode of lead  22 , distal electrode  25 A, to test device  44  in a unipolar configuration. In other examples, coupling  51  and test device  44  may be connected to both electrodes  25  of lead  22  in a bipolar configuration, and auxiliary electrode  48  and cable  50  may be omitted. 
     Test device  44  receives one or more signals sensed using distal electrode  25 A with auxiliary electrode  48  acting as a reference electrode. In some examples, test device  44  measures a pacing impedance signal using distal electrode  25 A. In some examples, test device  44  receives a cardiac electrogram signal sensed using distal electrode  25 A with auxiliary electrode  48  acting as a reference electrode. An implanting physician may use the signals and/or values derived from the signals to determine whether a current position/depth of distal electrode  25 A is adequate for sensing and therapy delivery by IMD  16  via distal electrode  25 A. In the case of HPCS pacing, for example, the presence of HPCS features in the cardiac electrogram (e.g., features indicative of the electrical activity of the His bundle or bundle branches) may indicate an adequate position/depth of distal electrode  25 A. 
     In some cases, lead  22 , or a portion thereof, is rotated during the implantation procedure. However, test device  44  and cables  46  and  50  may not be able to rotate with lead  22 . Furthermore, rotation of lead  22  may introduce artifacts or other noise into the signals used to determine whether its position/depth is adequate. For example, relative rotation of portions of the conductive pathway may introduce such noise, e.g., due to make/break events occurring during the relative rotation. The noise may corrupt the signals such that the adequacy of the position/depth of electrode  25 A cannot be determined during rotation. As described in greater detail below, rotational electrical coupling  51 , e.g., including first and second conductive components, may allow relative rotation of lead  22  and cable  46 , and mitigate noise associated with such rotation. 
       FIG.  3    is a cross-sectional diagram of an example configuration of a rotational electrical coupling  51 A. In accordance with techniques of this disclosure, rotational electrical coupling  51 A may facilitate rotation of lead  22  relative to test device  44  by including a portion of a conductive pathway that is rotationally fixed, like test device  44 , and another portion of the conductive pathway that is rotatable with lead  22 . Furthermore, rotational electrical coupling  51 A may include features to mitigate noise that could otherwise be introduced into the signals received by test device  44  via electrodes  25  during rotation of lead  22 . 
     Rotational electrical coupling  51 A may be configured to establish electrical communication between distal electrode  25 A and, via lead connector  29 , test device  44 . Lead  22  may mechanically support rotational electrical coupling  51 A, and test device  44  may be in electrical contact with rotational electrical coupling  51 A (e.g., via cable  46 ). In some cases, electrical contact between test device  44  and rotational electrical coupling  51 A may be due to test device  44  being attached, fixed, or otherwise secured to rotational electrical coupling  51 A or a portion of lead connector  29  electrically coupled to rotational electrical coupling  51 A. As shown in  FIG.  3   , rotational electrical coupling  51 A includes a first conductive component  60 A and a second conductive component  64 A. 
     First conductive component  60 A and second conductive component  64 A may be configured to rotate relative to each other. For example, first conductive component  60 A, but not second conductive component  64 A, may be rotationally fixed to lead body  23 . In this way, lead body  23 , and thus first conductive component  60 A, may rotate relative to second conductive component  64 A while second conductive component  64 A maintains electrical communication between first conductive component  60 A and test device  44 . 
     In the illustrated example of  FIG.  3   , second conductive component  64 A includes a pin  63  and a cap  62  that are secured to each other (e.g., crimped, welded etc.). Pin  63  may extend from a distal portion  66  to a proximal portion  68 . Pin  63  may carry cap  62  and may be stationary relative (e.g., rotationally fixed) to cap  62  as first conductive component  60 A rotates relative to second conductive component  64 A. 
     Cap  62  may be electrically connected to pin  63 . In examples, cap  62  and pin  63  are electrically connected by physical contact with each other, e.g., being adjacent to each other and/or physically abutted to each other. Cap  62  of second conductive component  64 A may also be electrically connected to test device  44 , e.g., via cable  46  and distal cable connector  42 . As such, cap  62  and pin  63  may be configured to establish and maintain electrical communication between first conductive component  60 A and test device  44 . In some cases, cap  62  is positioned on proximal portion  68  of pin  63 . In such examples, cap  62  may define a recess configured to receive proximal portion  68 . IMD  16  may be electrically connected to cap  62 . 
     First conductive component  60 A is electrically connected to second conductive component  64 A; in addition, first conductive component  60 A is electrically connected to a connector  29 . Connector  29  is configured to establish electrical communication between circuitry of IMD  16  and electrodes  25 . Lead proximal portion  24  may mechanically support connector  29 . Connector  29  may include a lead electrical connector body  34  (“connector body  34 ”) configured to house at least a portion of one or more conductors (e.g., conductors  52 ,  54 ) to which electrodes  25  may be electrically connected. In examples, the one or more conductors include a conductive cable  36  (“cable  36 ”) extending from IMD  16  and into lead electrical connector body  34 . Distal portion  66  of pin  63  may be positioned within lumen  39  of connector body  34 . Proximal portion  68  of pin  63  may extend beyond a proximal end  70  of connector body  34 . 
     First conductive component  60 A may include a sleeve  38  of connector  29 . Sleeve  38  may be electrically connected to cable  36  and configured to electrically communicate with electrode  25 A via cable  36 . In examples, sleeve  38  is crimped, welded, or otherwise secured to cable  36 . In turn, first conductive component  60 A may be rotationally fixed to connector body  34 . Sleeve  38 , and at least a portion of cable  36 , may be disposed within a lumen  39  defined by an inner surface of connector body  34 . That is, connector body  34  may mechanically support sleeve  38 . 
     In examples, first conductive component  60 A is in abutment with second conductive component  64 A to establish electrical communication without being secured (e.g., rotationally fixed) to second conductive component  64 A. Thus, second conductive component  64 A of rotational electrical coupling  51 A may be electrically connected to electrode  25 A and with circuitry of IMD  16  via first conductive component  60 A. At least a portion of second conductive component  64 A may be positioned proximal to first conductive component  60 A. For example, cap  62  may be proximal to sleeve  38 . 
     In examples, connector body  34  houses an electrically insulative bearing  72  (“insulative bearing  72 ”) defining a channel configured to receive at least a portion of rotational electrical coupling  51 A. Insulative bearing  72  may be formed from polyether ether ketone (PEEK) or other insulative materials. Insulative bearing  72  may be configured to facilitate rotation of at least a portion of rotational electrical coupling  51 A. In examples, the channel defined by insulative bearing  72  is configured to receive distal portion  66  of pin  63 . The channel may be configured to enable second conductive component  64 A to substantially freely rotate within the channel. For instance, the inner surface of insulative bearing  72  defining the channel may be smooth such that any contact between insulative bearing  72  and second conductive component  64 A does not substantially resist rotation of second conductive component  64 A. In examples, insulative bearing  72  is bonded or otherwise secured to sleeve  38  (and, in turn, first conductive component  60 A). In examples, insulative bearing  72  is bonded or otherwise secured to connector body  34 . 
     As indicated above, rotational electrical coupling  51 A may include features to mitigate noise that could otherwise be introduced into the signals received by test device  44  via distal electrode  25 A during rotation of lead  22 . For example, rotational electrical coupling  51 A may comprise a material selected for adequate conduction and relatively lower friction, such as tin, gold, silver, or copper. In some examples, rotational electrical coupling  51 A may comprise the material, e.g., be coated with the material. In some examples, rotational electrical coupling  51 A may consist essentially of the material, e.g., may include other materials that do not materially affect the properties rotational electrical coupling  51 A, such as properties related to electrical conduction and friction. 
       FIG.  4    is a conceptual diagram, illustrating an example rotational electrical coupling  51 B that includes a first conductive component  60 B and a second conductive component  64 B. As shown in  FIG.  4   , first conductive component  60 B defines one or more fingers  80 A- 80 C (collectively, “fingers  80 ”). An inner surface  82  of second conductive component  64 B, for example an inner surface of pin  63 , may be configured to be in abutment with fingers  80 . In some examples, inner surface  82  of second conductive component  64 B may define one or more protrusions  84  configured to be in abutment with fingers  80 . First conductive component  60 B and second conductive component  64 B may be dimensioned such that when first conductive component  60 B is inserted into second conductive component  64 B, first conductive component  60 B and second conductive component  64 B compress fingers  80  against protrusions  84  to establish electrical contact. Fingers  80  may be elastically deformable such that fingers  80  are urged into contact with inner surface  82  and/or protrusions  84 . 
       FIG.  5    is a cross-sectional diagram of an example rotational electrical coupling  51 C. As shown in  FIG.  5   , rotational electrical coupling  51 C includes a first conductive component  60 C and a second conductive component  64 C. First conductive component  60 C and second conductive component  64 C are in electrical contact. In the illustrated example, rotational electrical coupling  51 C is configured such that first conductive component  60 C rotates relative to second conductive component  64 C. That is, first conductive component  60 C may be in abutment with, but not secured to, second conductive component  64 C. In the example of  FIG.  5   , first conductive component  60 C of rotational electrical coupling  51 C may correspond to pin  63 , and second conductive component  64 C of rotational electrical coupling  51 C may correspond to cap  62 . 
     First conductive component  60 C may be secured to connector  29 . For example, first conductive component  60 C may be crimped onto sleeve  38 , bonded to insulative bearing  72 , etc. As a result, first conductive component  60 C may be configured to rotate relative to second conductive component  64 C as connector body  34  (and lead body  23 ) rotates relative second conductive component  64 C. 
     Rotational electrical coupling  51 C may include a conductive element  86  configured to maintain first conductive component  60 B in electrical communication with second conductive component  64 B as first conductive component  60 B rotates relative to second conductive component  64 B. As shown in  FIG.  5   , first conductive component  60 C may define a recess at a section  92  in which conductive element  86  may be positioned. In this way, conductive element  86  may be positioned between first conductive component  60 C and second conductive component  64 C such that conductive element  86  is in electrical contact with an outer surface  88  of first conductive component  60 C and an inner surface  90  of second conductive component  64 C. 
     In examples, conductive element  86  includes one or more ball bearings configured to be in abutment with outer surface  88  of first conductive component  60 C and inner surface  90  of second conductive component  64 C. The ball bearings may be formed from steel or any other suitable material (e.g., a conductive metal). The ball bearings may surround the shaft of first conductive component  60 C at section  92 . 
     In some cases, conductive element  86  includes an elastically deformable element, such as a spring, one or more beams, etc. In such cases, first conductive component  60 C and second conductive component  64 C may compress the elastically deformable element positioned between them to establish electrical contact. In examples where conductive element  86  is a spring, conductive element  86  may be in the shape of a ring surrounding a shaft of first conductive component  60 C at section  92 . The elastically deformable element may be configured to be in abutment with outer surface  88  of first conductive component  60 C and inner surface  90  of second conductive component  60 C. The elastically deformable element may be formed from steel or any other suitable material (e.g., a conductive metal). In examples where conductive element  86  includes one or more beams, the beams may be configured to facilitate electrical contact between first conductive component  60 C and second conductive component  64 C, e.g., as described in U.S. Pat. No. 4,764,132. 
     The likelihood of noise in the signals received by test device  44  from electrodes  25  may be reduced as the consistency of electrical and physical contact between first conductive component  60 A- 60 C and second conductive component  64 A- 64 C during relative rotation increases. Thus, these features, e.g., the material and geometric properties of first conductive component  60 A- 60 C, second conductive component  64 A- 64 C, and/or conductive element  86  may allow an implanting physician to observe relatively noise-free signals, or data derived therefrom, during rotation of lead  22 , which may reduce the time and effort need to identify an adequate implant position/depth for electrodes  25 . 
       FIG.  6    is a flow diagram illustrating an example technique for testing lead  22  during an implantation procedure using rotational electrical coupling  51 A. Rotational electrical coupling  51 A will be described for the example of  FIG.  6   , but any devices herein, or combinations of devices, may perform similar techniques of  FIG.  6   . According to the example of  FIG.  6   , test device  44  may be electrically connected to rotational electrical coupling  51 A ( 600 ). In some examples, test device  44  comprises distal cable connector  42  or other connector configured to engage a portion of rotational electrical coupling  51 A, such as first conductive component  60 A. In this way, distal electrode  25 A of lead  22  is electrically connected to test device  44  via rotational electrical coupling  51 A as described herein. 
     Distal portion  27  of lead  22  may be positioned adjacent to cardiac tissue, e.g., the intraventricular septum, at a desired location for sensing and delivery of therapy by IMD  16 , e.g., for HPCS pacing. With distal electrode  25 A electrically connected to test device  44  and located as desired relative to the cardiac tissue, test device  44  may begin to measure impedance and sense a cardiac EGM via distal electrode  25 A ( 602 ). Once initiated, the measurement and sensing by test device  44  may be substantially continuous, e.g., at a sampling rate during a period of time that includes a plurality of cardiac cycles and a plurality of positions/depths of distal electrode  25 A. While test device  44  measures or senses one or more signals, lead  22  or a portion thereof may be rotated to advance distal electrode  25 A within cardiac tissue ( 604 ). In some cases, distal electrode  25 A may additionally be repositioned to different entry points of and trajectories through cardiac tissue. 
     Based on an output of test device  44  that is based on the one or more signals obtained via distal electrode  25 A, the implanting physician may determine whether a current position/depth of distal electrode  25 A is adequate for the sensing and delivery of therapy by IMD  16  ( 606 ). If the current position/depth is not adequate (NO of  606 ), then the physician may continue to rotate lead  22  relative to tissue of heart  12  while test device  44  continues to acquire one or more signals via distal electrode  25 A. If the current position/depth is adequate (YES of  606 ), then the physician may end that portion of an implantation procedure for IMD  16  and lead  22  ( 608 ). 
     The techniques described in this disclosure may be implemented, at least in part, in hardware, software, firmware or any combination thereof. For example, various aspects of the described techniques may be implemented within one or more processors or processing circuitry, including one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or any other equivalent integrated or discrete logic circuitry, as well as any combinations of such components. The term “processor” or “processing circuitry” may generally refer to any of the foregoing logic circuitry, alone or in combination with other logic circuitry, or any other equivalent circuitry. A control unit including hardware may also perform one or more of the techniques of this disclosure. 
     Such hardware, software, and firmware may be implemented within the same device or within separate devices to support the various operations and functions described in this disclosure. In addition, any of the described units, circuits or components may be implemented together or separately as discrete but interoperable logic devices. Depiction of different features as circuits or units is intended to highlight different functional aspects and does not necessarily imply that such circuits or units must be realized by separate hardware or software components. Rather, functionality associated with one or more circuits or units may be performed by separate hardware or software components or integrated within common or separate hardware or software components. 
     The techniques described in this disclosure may also be embodied or encoded in a computer-readable medium, such as a computer-readable storage medium, containing instructions that may be described as non-transitory media. Instructions embedded or encoded in a computer-readable storage medium may cause a programmable processor, or other processor, to perform the method, e.g., when the instructions are executed. Computer readable storage media may include random access memory (RAM), read only memory (ROM), programmable read only memory (PROM), erasable programmable read only memory (EPROM), electronically erasable programmable read only memory (EEPROM), flash memory, a hard disk, a CD-ROM, a floppy disk, a cassette, magnetic media, optical media, or other computer readable media. 
     Various examples have been described. These and other examples are within the scope of the following claims.