Implantable medical lead and fixation assembly therefor

Abstract

The invention is directed a fixation assembly for a medical lead providing better energy dissipation during MRI conditions. The fixation assembly comprises an elongated body extending between a distal end and a proximal end, wherein the fixation assembly further comprises at least one electrode and / or at least one radiopaque marker, wherein the elongated body comprises at least one energy dissipating element located in close proximity to the at least one radiopaque marker and / or the at least one electrode, wherein the material of the at least one energy dissipating element exhibits a permittivity that is equal to or greater than 4 F / m.

Description

[0001] Applicant: BIOTRONIK SE & Co. KG

[0002] Date: 18.08.2025

[0003] Our Reference: 24.035P-WO

[0004] Implantable medical lead and fixation assembly therefor

[0005] The invention generally relates to a fixation assembly of an implantable medical lead and a respective implantable medical lead for electrical therapy like bradycardia and / or conduction system pacing (CSP).

[0006] Medical leads implanted in a patient’s body for electrical cardioversion or pacing of the heart are generally known in the art. In particular, electrically transmissive leads may be implanted in or about the heart to reverse (i.e., defibrillate or cardiovert) certain life-threatening arrhythmias or to stimulate contraction (pacing) of the heart. Electrical energy is transmitted from a pulse generator which is electrically connected to the lead. Such transmitted electrical energy is applied to the heart via the lead to return the heart to normal rhythm or to stimulate the heart. Leads have also been used to sense conditions, materials or events (generally referred to as "sense" or "sensing") in the body, such as electrical potential in the atrium or ventricle of the heart. For that such medical lead may be connected to a sensing device using a connector assembly at the proximal end of the medical lead. Alternatively, the sensed signals may be transmitted to and processed by the pulse generator, and, for example, used for pacing control. Further, medical leads may be in connection with spinal cord stimulation (SCS), deep brain stimulation (DBS) or neurostimulation devices.

[0007] Implantable medical leads represent the electrical link between the stimulation signal generator or processing unit for measured signals and the patient’s body tissue which is to be treated or sensed. Accordingly, the medical lead must be reliably mechanically and electrically connected to the patient’s body tissue at a pre-defined target location. For that, a medical lead often comprises a fixation assembly, which may be located at a distal end section of the lead, wherein an electrode, for example, formed as a helical wire mounted at its distal end. Such helical wire (helix) penetrates into and thereby electrically connects to the target tissue (e.g. the heart’s septum) when the lead tip is pressed against the tissue and is rotated. The helical structure pulls the lead tip into the tissue at the target position. Accordingly, such fixation supports the implantation and prevents the lead from dislocation.

[0008] During implantation of a medical lead, a very high degree of precision is necessary, when an electrode is to be placed at the target location within the patient’s body, for example at the HIS bundle for a conduction system pacing.

[0009] Therefore, different imaging techniques are used during implantation and subsequent monitoring. Typically, Magnetic Resonance Imaging (MRI) and X-ray techniques are used to provide the health care practitioner (HCP) with the instantaneous information about the lead position with respect to the target location, for example, the HIS bundle of the human heart.

[0010] MRI uses strong alternating electromagnetic fields at radio frequencies (e.g. 64 MHz or 128 MHz) to obtain graphic information about structures inside the body, i.e. organs or blood flow. MRI can be used to take detailed images of any part of the body (e.g. head, joints, abdomen, legs, etc.) without X-ray exposure and provides a good soft tissue contrast. X-ray imaging utilizes high-energy electromagnetic radiation. When directed at a human body, a portion of the X-rays will be absorbed depending on the density and / or the type of material through which they are directed. Accordingly, X-rays are used to create an instantaneous 2- dimensional absorption image of a patient’s body section and are therefore often used to monitor implantation processes. A radiopaque marker attached to a specific position at a medical device is commonly used to visualize the relevant section of such device.

[0011] Today’s medical leads typically contain metal components such as electrodes and radiopaque markers, in particular at their distal end section. However, when such a metal component is exposed to the high frequency electromagnetic fields used during MRI the metal component and thereby the medical lead heat up. Heat dissipation by blood flow is usually not sufficient and the bodily tissue being in contact with the respective section of the medical lead may be damaged.

[0012] 24.035P-WO / 18.08.2025 In order to enhance heat dissipation during MRI, state of the art medical leads comprise at their distal end section precious radiopaque components extending over a larger surface area for increased heat dissipation. The disadvantages of such expensive design are a less precise X-ray localization due to the large component’s extension, an increased probability of oversensing in case metal parts are in loose contact with the therapeutic path and a need for additional electrical isolation to avoid loss of current. Further, the energy dissipation is limited by the size of the lead tip.

[0013] Accordingly, an object of the proposed invention is to provide a fixation assembly having reduced heat generation under MRI conditions in order to protect human tissue during MRI scanning while maintaining the medical lead’s X-ray visibility, e.g. for implantation monitoring.

[0014] The above-mentioned object is solved by a fixation assembly having the features of claim 1 and by an implantable medical lead having the features of claim 12.

[0015] The object is solved by a fixation assembly for a medical lead, wherein the fixation assembly comprises an elongated body extending between a distal end and a proximal end, wherein the fixation assembly may be located at a distal end section of the medical lead, wherein the fixation assembly further comprises at least one electrode and / or at least one radiopaque marker, wherein the elongated body further comprises at least one energy dissipating element located in close proximity to the at least one radiopaque marker and / or the at least one electrode, wherein the material of the at least one energy dissipating element (hereinafter also referred to as “the energy dissipating element”) exhibits a permittivity that is equal to or greater than 4 F / m.

[0016] In one embodiment, the fixation assembly is used for an implantable medical lead and is designed to enhance the safety and functionality of medical leads used in various therapeutic applications, such as pacemaking or Bradycardia therapy. This assembly is notably beneficial for applications within the human body, where precise positioning and reduced risk of tissue damage during MRI operations are paramount. The medical lead comprises at

[0017] 24.035P-WO / 18.08.2025 least an electric connector at its proximal end and a fixation assembly at its distal end which is described in the following in more detail.

[0018] The fixation assembly comprises an elongated body and at least one electrode at the distal and / or the proximal end of the fixation assembly and / or at least one radiopaque marker. The elongated body may have a solid or tube-like hollow cylindrical and / or hollow conical form and may extend along a longitudinal axis, wherein in one embodiment, an electrode may project from the distal tip of the elongated body. The outer surface of the body may be straight or may comprise steps. The at least one electrode and / or the at least radiopaque marker may be supported by or integrated within the body. Further, the body may have an inner lumen guiding an electrode and a cable-like conductor connecting this electrode to the electrical connector at the proximal end of the medical lead. Further electrical conductors may extend within the body electrically connecting the electrical connector and the respective electrode.

[0019] In one embodiment, an electrode located at the distal tip of the elongated body may have a helical shape (i.e. a helical wire forming an electrode, in the following short helix). The helix may be electrically connected through the medical lead to the electrical connector at the proximal end of the medical lead by the conductor. During implantation, the helix (movable relative to the fixation body) may be at least partially retracted within the inner lumen of the body of the fixation assembly and may be fully extended from the distal tip of the elongated body at the target position for implantation within the target tissue. Alternatively, the helix may be fixedly attached to the distal tip of the fixation body such that it projects from the distal tip of the elongated body. The helix is a wire that is a three-dimensional, spiraling wire curve that wraps around a cylinder or cone. Different geometric shapes and properties of a helix can be used according to the individual properties at the patient’s target location. Unlike a circle that lies flat in a single plane, the helix extends into three dimensions, moving upwards or downwards along an axis as it circles around. The axis of the helix is the central line around which the helix spirals. The helix axis can be straight or curved. The pitch of the helix is the distance between two corresponding points on adjacent turns, measured parallel to the axis. The helix may be a uniform helix (i.e. having a constant pitch) meaning the

[0020] 24.035P-WO / 18.08.2025 spacing between each turn is the same throughout the length of the helix. The cross section of the wire used for the helix may be circular, square, triangular or any other suitable form.

[0021] In one embodiment, the electrode may have a ring-like form, wherein the electrode may be attached to the outer surface of the elongated body or integrated within the outer surface of the body. Such electrode is electrically connected through the body of the fixation assembly and the medical lead to the electrical connector at the proximal end of the medical lead.

[0022] The at least one radiopaque marker ensures X-ray visibility of the fixation assembly or of its electrodes during implantation and / or further monitoring. The at least one radiopaque marker comprises an X-ray absorbing metal, for example at least one metal of the group comprising Iridium and Platinum. The at least one radiopaque marker is, for example, positioned close to the distal tip of the elongated body. The at least one radiopaque marker may be integrated within or may be attached to the elongated body, for example at its outer or inner surface.

[0023] The at least one energy dissipating element comprises a material having a permittivity of at least 4 F / m, for example a permittivity of at least 10 F / m is even more beneficial. The permittivity is the absolute permittivity describing the electric polarizability of the (dielectric) material of the energy dissipating element. Further, according to the invention, the at least one energy dissipating element is located in close proximity to the at least one radiopaque marker and / or the at least one electrode. This configuration allows a reduced generation of MRI-induced heat caused by high-frequency magnetic fields. For example, the at least one energy dissipating element consists of a thermoplastic polymer or of matrix material comprising a thermoplastic polymer with at least one additive. The thermoplastic polymer may comprise at least one material of the group comprising Polyether ether ketone (PEEK), Acrylonitrile butadiene styrene (ABS), Polyamide (Nylon), Polypropylene (PP), Polycarbonate (PC), Polyester, Polyester sulfone (PES), Polyoxymethylene (POM) and Polytetrafluoroethylene (PTFE); and the additive may comprise at least one material of the group comprising Barium sulfate, Titanium dioxide, Carbon, Barium sulfate, Titanium Dioxide, Zinc oxide, Metal titanates as Barium Titanate and Calcium titanate, lead-free piezoelectric composites as Barium-calcium zirconate titanate. The additive may have the form of Fibers, Threads, Particles, Granulates, Sintered beads and / or Slurries. The weight

[0024] 24.035P-WO / 18.08.2025 percentage of the at least one additive may vary, for example, between 5% and 30% of the energy dissipating material, e.g., between 10% to 25% of the energy dissipating material.

[0025] In one embodiment, besides reduced MRI-induced heat generation, the at least one energy dissipating element further exhibits a high thermal conductivity, which enables increased heat dissipation away from the human tissue. This material property is mainly provided by the used additives. For example, the thermal conductivity of the energy dissipating material lies in the range of 0.1 - 50 W / m / K, while a range of 15 - 31 W / m / K is even more beneficial for heat dissipation.

[0026] Besides the material properties of the energy dissipating element, its form and / or positioning with respect to the at least one electrode and / or at least one radiopaque marker of the fixation assembly affect its energy dissipating effect. The at least one energy dissipating element is located in proximity to the at least one radiopaque marker and / or the at least one electrode, for example, the energy dissipating element is located directly adjacently to the at least one radiopaque marker and / or the at least one electrode or may have a maximum distance of 15mm, in particular 5 mm, in longitudinal direction (i.e. the direction of the longitudinal axis of the body) and / or a maximum distance of 3.33 mm, in particular 1 mm, in axial direction (direction perpendicular to the longitudinal direction) to the at least one radiopaque marker and / or the at least one electrode.

[0027] In one embodiment the material of the at least one energy dissipating element exhibits an electric conductivity of at least 1 pS / m, for example an electric conductivity of at least 8 pS / m is even more beneficial. The increased electrical conductivity leads to a decrease of the amount of heat generated by static electric induction. The above-mentioned materials may be configured such that they exhibit this property, as well.

[0028] In one embodiment the radiopaque elements may exhibit a predefined form, for example a ring-like structure. This ring-like structure may be over-molded over a pre-defined section of the elongated body. The ring-like shape enables X-ray visibility of the medical lead for each rotational state during implantation. The position and geometry of the at least one ringlike radiopaque marker is characterized by its distance with respect to the distal tip of the

[0029] 24.035P-WO / 18.08.2025 fixation assembly, its thickness and its dimension in longitudinal direction. For example, it may have a distance of at least 0.1 mm from the distal tip of the elongated body, a layer thickness between 0.05 mm and 1.5 mm and a dimension between 0.1 mm and 2 mm in longitudinal direction.

[0030] In one embodiment, the energy dissipating element constitutes at least a section of the elongated body itself, wherein the elongated body is a basically tube-like element that supports the at least one radiopaque marker and / or the at least one electrode, for example, in the area where the at least one energy dissipating element forms at least a section of the elongated body, for example the distal end section of the elongated body. In one embodiment, the energy dissipating element may extend proximally to a ring-shaped electrode integrated within the elongated body. The at least one electrode and / or the at least one radiopaque marker may be directly supported by the energy dissipating element constituting a section of the body, for example, the energy dissipating element may form an inner or outer support (in axial direction) to the at least one electrode and / or the at least one radiopaque marker. Such configuration allows close proximity between the at least one energy dissipating element on one hand and the at least one radiopaque marker and / or at least one electrode on the other hand. Especially beneficial is the fact that a large area may be covered by the at least one energy dissipating element which increases its effect. In addition, the production process of this configuration is easy as the different elements of the fixation assembly may be provided by molding. In case the energy dissipating element constitutes at least a section of the elongated body, its maximum outer radial extension and its minimal inner radial extension shall coincide with the corresponding values of the elongated body, forming a continuous inner and outer surface. Regardless, recesses, cuts and other structural elements may be incorporated into the energy dissipating element.

[0031] In one embodiment the at least one electrode and / or at least one radiopaque marker form a positive-locking connection to the elongated body. In one embodiment, the energy dissipating element is located in this area. The energy dissipating element may either be positioned between the contact surfaces of above-mentioned positive-locking connection or provides the positive-locking connection since it constitutes the elongated body at this connection area. Thereby, a reliable connection of the at least one electrode and / or the

[0032] 24.035P-WO / 18.08.2025 radiopaque marker and the body is provided. In the case the energy dissipating element constitutes the positive-locking connection, additionally a very close proximity and therefore an effective energy dissipation is realized. In one embodiment, the at least one radiopaque marker is produced by molding thereby providing a low-cost manufacturing method.

[0033] In one embodiment, the at least one energy dissipating element forms a ring-like section of the elongated body and is located directly adjacently or spaced a pre-determined distance apart in longitudinal direction of the elongated body to the at least one electrode and / or the at least one radiopaque marker. In this embodiment such close proximity of metal parts and energy dissipating material is an effective way of heat reduction, allowing for a maximized energy dissipating effect at MRI conditions.

[0034] In one embodiment, the at least one energy dissipating element forms a cover tube section covering a conductor for the at least one electrode, wherein the conductor with the cover tube is located within an inner lumen of the elongated body. The tubular embodiment is not exhaustive, other shapes of a cover layer for the conductor such as, for example, an elliptical cross section or a rectangular cross section are possible, as well. By this configuration particularly the heat production by currents induced by the inner electrical conductor can be reduced.

[0035] In one embodiment, the at least one energy dissipating element is located directly adjacently to a flexible section of the elongated body. Such flexible section may be located between a distal end section of the fixation assembly and an electrode accommodated proximally from the distal end section. This embodiment may reduce heat dissipation generated from the distal end section comprising, for example, a radiopaque marker and / or another electrode, and the electrode located proximal from the distal end section at the same time.

[0036] The energy dissipating element may comprise a dimension in longitudinal direction of at least 0.1 mm, for example between 0.5 mm and 1.5 mm as well as a thickness (dimension in radial direction) of at leastO.Ol mm, for example, of at least 0.08 mm for providing a considerable heat dissipation during MRI conditions and / or a combination of at least two

[0037] 24.035P-WO / 18.08.2025 energy dissipating elements as explained above or below accommodated at a single fixation assembly.

[0038] In one embodiment the radiopaque marker comprises a first ring-like section and a second ring-like section spaced a pre-determined distance apart in longitudinal direction of the elongated body, wherein a X ray transparent element, e.g. a X ray ring-like element, is located in longitudinal direction between the first ring-like section and the second ring-like section of the radiopaque marker. The X ray transparent element may comprise at least one material of the group comprising thin walled metals as aluminum, stainless steel and / or titanium; and / or thermoplastic materials as Polyether ether ketone (PEEK), Acrylonitrile butadiene styrene (ABS), Polyamide (Nylon), Polypropylene (PP), Polycarbonate (PC), Polyester, Polyester sulfone (PES), Polyoxymethylene (POM) and / or Polytetrafluoroethylene (PTFE). The heat dissipating element itself can also be the Xray transparent element. This embodiment allows a good visibility of the radiopaque marker for positioning during implantation as it forms a specific pattern (two ring-like, spaced apart sections). For providing sufficient heat dissipation this radiopaque marker may directly be accommodated on a section of the elongated body, which constitutes an energy dissipating element. Furthermore, such fixation assembly may be cost-efficiently produced, e.g. by molding.

[0039] In one embodiment, a retractable fixation element extends from the distal end of the elongated body. The fixation element may be retracted during implantation within the elongated body of the fixation assembly and extended from the elongated body at the target location for fixation of the medical lead within the patient’s tissue. The fixation element may form an electrode at the same time for sensing and / or stimulation and / or may have a helical form for reliable fixation within the target tissue. In the extended state, the fixation element may still be surrounded at its proximal end by the elongated body thereby providing close proximity so that heat can be dissipated at MRI conditions.

[0040] In one embodiment the elongated body comprises at least one electrically insulating layer. The at least one electrically insulating layer electrically separates the electrode(s) and the radiopaque element as well as the conductor(s) supplying the electrical energy to the

[0041] 24.035P-WO / 18.08.2025 electrode(s). The electrically insulating layer comprises at least one material of the group comprising thermoplastic materials as Polyether ether ketone (PEEK), Acrylonitrile butadiene styrene (ABS), Polyamide (Nylon), Polypropylene (PP), Polycarbonate (PC), Polyester, Polyester sulfone (PES), Polyoxymethylene (POM), Polytetrafluoroethylene (PTFE); and / or semi-crystalline polymer, thermosets, elastomer (PEEK, PU, PA, LSR).

[0042] By addressing the specific challenges associated with heat dissipation during MRI conditions and ensuring high precision in lead positioning during implantation, this invention marks a substantial improvement over existing technologies for medical leads, especially in the field of conduction system pacing (CSP) or bradycardic therapy. Additionally, the medical lead may be used for defibrillation, deep brain stimulation or neurostimulation.

[0043] Further, the problem is solved by an implantable medical lead comprising an electrical connector at its proximal end and a fixation assembly located at a distal section of the medical lead. The electrical connector is configured to electrically and mechanically connect the medical lead to the pulse generator and / or sensing / data processing device. The electrical connector and the fixation assembly are mechanically connected by an elongated intermediated part which may comprise an electrically insulating outer layer and at least one electric conductor electrically connecting the at least one electrode of the fixation assembly to the respective port at the electrical connector. The intermediate part may additionally comprise at least one electrode and a respective electrical connector.

[0044] The present invention will now be described in further detail with reference to the accompanying schematic drawings, wherein

[0045] Fig. 1 shows an embodiment of an implantable medical lead with a first embodiment of a fixation assembly in a side view,

[0046] Fig. 2 depicts the embodiment of a fixation assembly of Fig. 1 in a side view,

[0047] Fig. 3 shows a second embodiment of a fixation assembly in a side view and partially in a longitudinal section,

[0048] 24.035P-WO / 18.08.2025 Fig. 4 depicts a third embodiment of a fixation assembly in a longitudinal section, and

[0049] Fig. 5 shows a fourth embodiment of a fixation assembly in a longitudinal section.

[0050] A typical configuration of a medical lead 100 used for CSP or bradycardia therapy is shown in Fig. 1. It comprises an electrical connector 110 at its proximal end and a first embodiment of a fixation assembly 200 at its distal end extending to the distal tip of the medical lead. The purpose of the medical lead 100 is to facilitate the entirety of required functions, including but not limited to power supply, fixation at a target tissue of a patient as well as sensing and / or stimulating via electrodes 213, 214 provided at the fixation assembly 200.

[0051] The fixation assembly 200 comprises a distal electrode 213 in form of a retractable helix a ring-like proximal electrode 214, and an elongated tubular body 210 having a longitudinal axis 211 (see Fig. 2). An energy dissipating element 217 constitutes a ring-like section of the elongated body 210 located between the distal electrode 213 and the proximal electrode 214 in longitudinal direction (the longitudinal direction extends along the longitudinal axis 211) and having a dimension of, for example, 4 mm in longitudinal direction. The distal electrode 213 forms a fixation element for reliable fixation of the medical lead 100 within the target tissue of the patient. The distance of the distal electrode 213 and the energy dissipating element 217 is, for example, 3 mm whereas the distance of the proximal electrode 214 and the energy dissipating element 217 is 4 mm, both in longitudinal direction. The energy dissipating element 217 consists of, for example, PEEK (e.g. KetaSpire® KT 880 BK 95) or a matrix of PEEK (approx. 70 wt %) and an additive of Carbon fibers (approx. 30 wt %), e.g. KetaSpire® KT 880 CF 30. The material of the energy dissipating element 217 has a permittivity of 6 F / m and an electric conductivity of 8 pS / m. The above values for permittivity and electric conductivity apply to the materials mentioned with regard to below embodiments, as well.

[0052] The electrically conducting electrodes 213, 214 are prone to MRI induced heat. The energy dissipating element 217 is positioned to reduce heat production under MRI conditions and dissipates heat in longitudinal direction away from the distal electrode 213 and the proximal

[0053] 24.035P-WO / 18.08.2025 electrode 214, wherein the distal electrode 213 is in contact with human tissue in the implanted state. The thickness of the energy dissipating element reflected by the wall thickness of the elongated body 210 is, for example, 0.15 mm.

[0054] A second embodiment of a fixation assembly 300 is shown in Fig. 3. Third and fourth embodiments of the fixation assembly 400, 500 are shown in Fig. 4 to 5, the second to fourth embodiments are constructed in part similarly to the embodiment of Fig. 1 and 2. In the following, the differences of the respective fixation assembly from the first embodiment are indicated. With regard to the embodiments it is noted that components of the fixation assembly embodiments which correspond to each other and comprise the same composition and function have identical ones and tens digits but a different hundreds digit. It is referred to the respective explanation of these components relative to the other embodiments.

[0055] The fixation assembly 300 comprises a first energy dissipating element 317a that constitutes a ring-like section of the tubular body 310 similarly to the first embodiment of the fixation assembly 300. However, the first energy dissipating element 317a of this embodiment is overmolded by two ring-like radiopaque markers 315 at its outer surface, wherein the radiopaque markers 315 have a dimension of 0.7 mm in longitudinal direction, a wall thickness of 0.1 mm and a distance of 2.8 mm in longitudinal direction. The radiopaque markers 315 consist of, for example, Platinum Iridium alloy. The radiopaque markers 315 allow precise X-ray localization. They are positioned directly on the section of the elongated body 310 forming the first energy dissipating element 317a to exploit its energy dissipating properties. This fixation assembly embodiment further comprises a second energy dissipating element 317b forming a cover tube section covering an electrical conductor for a distal electrode 313. The second energy dissipating element 317b may consist of an extruded or braided carbon fiber reinforced PEEK. Its dimension in longitudinal direction is, for example, 15 mm and its wall thickness, e.g., 0.1 mm. The second energy dissipating element 317b is located in the inner lumen of the elongated body 310 shielding the conductor from MRI induction. Additionally, this second energy dissipating element’s 317b electric conductivity also reduces the heat induced by the conductor. The second energy dissipating element 317b is located under or at a flexible section of the fixation assembly 300 that is

[0056] 24.035P-WO / 18.08.2025 formed between the distal electrode 313 and a proximal electrode 314. The proximal electrode 314 may function as a sensing electrode.

[0057] Fig. 4 shows a third embodiment of the fixation assembly 400 having a tubular elongated body 410 with a distal section constituting a first energy dissipating element 417a, a flexible member 416 and a proximal electrode 414. The proximal electrode 414 may function as a sensing electrode. The flexible member 416 forms a form-locking connection with the first energy dissipating element 417a and a form-locking connection with the proximal electrode 414 by a U-shaped stepped structure. At the interface of the flexible member 416 and the proximal electrode 414 a third energy dissipating element 417d is provided by a stepped layer created by overmolding the proximal electrode 414 using carbon fiber reinforced PEEK. The position of the third energy dissipating element 417d is not limited to the interface between the flexible member 416 and the proximal electrode 414 but may be extended to another section of the proximal electrode 414 and the flexible member 416. The layer thickness of the third energy dissipating element 417d is, for example, 0.05 mm and its dimension in longitudinal direction is, for example, 1 mm.

[0058] Within an inner lumen of the elongated body 410, a distal helical electrode 413 is accommodated at a distal end of a conductor 419 electrically connecting the distal electrode 413 to the electrical connector at the proximal end of the medical lead. The conductor 419 is covered by a cover tube 417b as a second energy dissipating element shielding the conductor 419 during MRI conditions. The second energy dissipating element 417b may consist of a Carbon fiber reinforced PEEK.

[0059] The first energy dissipating element 417a, the second energy dissipating element 417b and the third energy dissipating element 417d provide a very effective energy dissipation during MRI conditions.

[0060] A fourth embodiment of the fixation assembly 500 is shown in Fig. 5. In contrast to all previous embodiments the whole elongated body 510 constitutes an energy dissipating element 517 from its proximal end to its distal tip consisting of Carbon fiber reinforced PEEK, where a helical distal electrode 513 protrudes from the elongated body 510. The

[0061] 24.035P-WO / 18.08.2025 energy dissipating element 517 is over-molded with a radiopaque marker 515 comprising a first (distal) ring-like section 515a and a second (proximal) ring-like section 515b that are spaced a pre-defined distance of, for example, 1.4 mm apart in longitudinal direction. An X ray transparent (ring-like) element 518 is located in longitudinal direction between the first ring-like section 515a and the second ring-like section 515b. The dimensions of the first ring-like section 515a and the second ring-like section 515b are, for example, 0.7 mm in longitudinal direction. This embodiment allows for an effective energy dissipation produced by the radiopaque marker 515 and cost-effective manufacturing of the fixation assembly 500. Additionally, because of its particular structure, the radiopaque marker 515 provides a good visibility during implantation under X ray radiation. The layer thickness of the first and second ring-like section 515a, 515b and of the X ray transparent element 518 is, for example, 0.1 mm.

[0062] 24.035P-WO / 18.08.2025 List of Reference Numbers

[0063] 100 medical lead

[0064] 110 electrical connector 200, 300, 400, 500 fixation assembly

[0065] 210, 310, 410, 510 elongated body

[0066] 211 longitudinal axis

[0067] 213, 313, 413, 513 distal electrode

[0068] 214, 314, 414 proximal electrode 217, 317a, 317b, 417a, 417b, 417d, 517 energy dissipating element

[0069] 315, 515 radiopaque marker

[0070] 416 flexible member

[0071] 419 conductor

[0072] 515a, 515b ring-like section of radiopaque marker 515 518 X ray transparent element

[0073] 24.035P-WO / 18.08.2025

Claims

Claims1. A fixation assembly (200, 300, 400, 500) for a medical lead (100), wherein the fixation assembly (200, 300, 400, 500) comprises an elongated body (210, 310, 410, 510) extending between a distal end and a proximal end, wherein the fixation assembly (200, 300, 400, 500) further comprises at least one electrode (213, 214, 313, 314, 413, 414, 513) and / or at least one radiopaque marker (315, 515), wherein the elongated body (210, 310, 410, 510) comprises at least one energy dissipating element (217, 317a, 317b, 417a, 417b, 417d, 517) located in close proximity to the at least one radiopaque marker (315, 515) and / or the at least one electrode (213, 214, 313, 314, 413, 414, 513), wherein the material of the at least one energy dissipating element (217, 317a, 317b, 417a, 417b, 417d, 517) exhibits a permittivity that is equal to or greater than 4 F / m.

2. The fixation assembly (200, 300, 400, 500) of claim 1, wherein the material of the at least one energy dissipating element (217, 317a, 317b, 417a, 417b, 417d, 517) exhibits an electric conductivity of at least 1 pS / m.

3. The fixation assembly (200, 300, 400, 500) of any one of the previous claims, wherein the at least one energy dissipating element (217, 317a, 417a, 417d, 517) constitutes at least a section of the elongated body (210, 310, 410, 510), wherein the elongated body (210, 310, 410, 510) is a basically tube-like element supporting the at least one radiopaque marker (315, 515) and / or the at least one electrode (213, 214, 313, 314, 413, 414, 513), for example, in the area where the at least one energy dissipating element (217, 317a, 317b, 417d, 517) forms at least a section of the elongated body (210, 310, 410, 510).

4. The fixation assembly (300, 400, 500) of any one of the previous claims, wherein the at least one electrode (414)and / or the at least one radiopaque marker (315, 515) forms a positive-locking connection to the elongated body (310, 410, 510), for example in the area where the at least one energy dissipating element (417d) forms at least a24.035P-WO / 18.08.2025section of the elongated body (410), wherein the at least one electrode ( 14) and / or the at least one radiopaque marker (315, 515) is, for example, produced by molding.

5. The fixation assembly (200, 300, 400, 500) of any one of the previous claims, wherein the at least one energy dissipating element (217, 317a, 417a, 517) forms a ring-like section of the elongated body (210, 310, 410, 510) and is located directly adjacently or spaced a pre-determined distance apart in longitudinal direction of the elongated body (210, 310, 410, 510) to the at least one electrode (213, 214, 313, 314, 413, 414, 513) and / or the at least one radiopaque marker (315, 515).

6. The fixation assembly (200, 300, 400) of any one of the previous claims, wherein the at least one energy dissipating element (317b, 417b) forms a cover tube section covering a conductor for the at least one electrode (213, 313, 413), wherein the conductor with the cover tube is located within an inner lumen of the elongated body (210, 310, 410).

7. The fixation assembly (300) of any one of the previous claims, wherein the at least one energy dissipating element (317b) is located directly adjacently to a flexible section of the elongated body (310).

8. The fixation assembly (500) of any one of the previous claims, wherein the radiopaque marker (515) comprises a first ring-like section (515a) and a second ring-like section (515b) spaced a pre-determined distance apart in longitudinal direction of the elongated body (510), wherein a X ray transparent element (518) is located in longitudinal direction between the first ring-like section (515a) and the second ringlike section (515b) of the radiopaque marker (515).

9. The fixation assembly (200, 300, 400, 500) of any one of the previous claims, wherein a retractable fixation element extends from the distal end of the elongated body (210, 310, 410, 510).24.035P-WO / 18.08.202510. The fixation assembly (200, 300, 400, 500) of claim 9, wherein the fixation element forms the at least one electrode (213, 313, 413, 513) and / or has a helical form.

11. The fixation assembly (200, 300, 400, 500) of any one of the previous claims, wherein the elongated body (210, 310, 410, 510) comprises at least one electrically insulating layer.

12. An implantable medical lead (100) comprising an electrical connector (110) at its proximal end and a fixation assembly (200, 300.

400. 500) located at a distal section of the medical lead (100) according to any one of the previous claims.24.035P-WO / 18.08.2025

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