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WO2024209225A1 - Hélice de fixation extensible pour fixation d'électrode - Google Patents

Hélice de fixation extensible pour fixation d'électrode Download PDF

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Publication number
WO2024209225A1
WO2024209225A1 PCT/IB2023/000182 IB2023000182W WO2024209225A1 WO 2024209225 A1 WO2024209225 A1 WO 2024209225A1 IB 2023000182 W IB2023000182 W IB 2023000182W WO 2024209225 A1 WO2024209225 A1 WO 2024209225A1
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WO
WIPO (PCT)
Prior art keywords
fixation helix
pacing
section
pacing device
tissue
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/IB2023/000182
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English (en)
Inventor
Jean-François Ollivier
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sorin CRM SAS
Original Assignee
Sorin CRM SAS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sorin CRM SAS filed Critical Sorin CRM SAS
Priority to CN202380097838.4A priority Critical patent/CN121057603A/zh
Priority to PCT/IB2023/000182 priority patent/WO2024209225A1/fr
Publication of WO2024209225A1 publication Critical patent/WO2024209225A1/fr
Anticipated expiration legal-status Critical
Pending legal-status Critical Current

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/18—Applying electric currents by contact electrodes
    • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/372—Arrangements in connection with the implantation of stimulators
    • A61N1/375—Constructional arrangements, e.g. casings
    • A61N1/37518—Anchoring of the implants, e.g. fixation
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/02—Details
    • A61N1/04—Electrodes
    • A61N1/05—Electrodes for implantation or insertion into the body, e.g. heart electrode
    • A61N1/056—Transvascular endocardial electrode systems
    • A61N1/057—Anchoring means; Means for fixing the head inside the heart
    • A61N1/0573—Anchoring means; Means for fixing the head inside the heart chacterised by means penetrating the heart tissue, e.g. helix needle or hook
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/18—Applying electric currents by contact electrodes
    • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/362—Heart stimulators
    • A61N1/365—Heart stimulators controlled by a physiological parameter, e.g. heart potential
    • A61N1/36507—Heart stimulators controlled by a physiological parameter, e.g. heart potential controlled by gradient or slope of the heart potential
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/18—Applying electric currents by contact electrodes
    • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/372—Arrangements in connection with the implantation of stimulators
    • A61N1/375—Constructional arrangements, e.g. casings
    • A61N1/3756—Casings with electrodes thereon, e.g. leadless stimulators

Definitions

  • the invention relates to the field of fixation structures for pacing devices (e.g., electrode catheters and/or leadless electrode devices) for cardiac pacing systems, such as but not limited to, left bundle branch (LBB) pacing, cardiac resynchronization or tachycardia (“tachy”) systems.
  • pacing devices e.g., electrode catheters and/or leadless electrode devices
  • cardiac pacing systems such as but not limited to, left bundle branch (LBB) pacing, cardiac resynchronization or tachycardia (“tachy”) systems.
  • LBB left bundle branch
  • tachy tachycardia
  • RVA right ventricular apex
  • LV left ventricle
  • LBBB left bundle branch block
  • LBBP Left bundle branch pacing
  • a helical fixation element or a pacing electrode is screwed into the LV septum, e.g., by puncturing the tissue with the distal tip of the helical fixation element (fixation helix).
  • the insertion depth into the LV septum may be determined by at least, the observed changes in the notch in VI lead, sheath angiography, fulcrum sign, and impedance monitoring.
  • the pacing electrode is slowly progressed to a determined depth into the septum (e.g., approximately 8 to 12 mm) by the application of a torque, meanwhile avoiding the perforation of the LV side of the septum.
  • LBB capture is confirmed based on acceptable pacing parameters.
  • Such confirmation may be based on at least one of a paced morphology of an RBBB pattern, a recording of an LBB potential, a stimulus-peak of the LVAT that shortens abruptly with increasing output or remains shortest and constant at low and high outputs, a selective LBBP and a non-selective LBBP, and a recording of a retrograde His potential or anterograde LBB potential during pacing.
  • the inner surface of the cavities of the RV and LV are "covered” with a thin robust skin (membrane or lining) named the “endothelium”, which is much harder to puncture than the inner section of the septum.
  • the tips of pacing or tachy leads are typically designed to avoid a risk of perforation of the septum. They may also be equipped with a soft tip (made of e.g. Silicone) to increase a stop surface. That is, when the helical fixation element or electrode (called “helix” hereinafter) is engaged with (e.g., screwed into) the (cardiac) issue, this tissue is pushed against the soft tip to stop the helix from rotation and further progression within the tissue.
  • the length of the helix may be limited, e.g., to an active length of about 2 mm.
  • a lead-based LBBP technique common features of implantation or placement processes include transvenous access, transseptal placement of the pacing lead into the LV septal sub-endocardium in the LBB region, and confirmation of capture of the LBB as referred to above.
  • a leadless medical device e.g., capsule
  • a leadless medical device e.g., capsule
  • a helix is implanted into the apex region, more preferably into the lower septum to limit the risk of perforation of the thin apex.
  • the typical length of the capsule is 35 mm including the helix (2 mm).
  • This capsule may be delivered through a vascular catheter introduced by a femoral access.
  • delivering the leadless device e.g., capsule
  • to the upstream first third of the septum is a challenging process because it requires access via a sharp turn or bend before engaging the tissue. This challenge becomes worse as the length of the leadless capsule (including the helix) increases.
  • another detrimental effect of placing and leaving the leadless capsule at this location results from permanent mechanical interactions of the implanted capsule with a tricuspid leaflet, which may create blood flow perturbation.
  • a pacing device as claimed in claim 1, a method of manufacturing a fixation helix, as claimed in claim 11, and a method of manufacturing a lead pacing device, as claimed in claim 14.
  • placement and insertion of the proposed pacing device into the patient's tissue requires less space, both prior to and after insertion, and reduces unwanted mechanical interactions due to the provision of its expandable section that extends when the fixation helix is screwed into the tissue, which thereby reduces the space required during insertion and allows a placement of the device in a bent state (i.e., a state of a curved or bent configuration) for minimal unwanted adverse mechanical interactions.
  • the expandable section of the fixation helix may be at least partially arranged (or its turns may be wound/shifted) around the housing of the pacing device.
  • the fixation helix is partially placed around or shifted over the housing (i.e., its turns are wound around the housing)
  • this provides the possibility of a device with a shorter longitudinal length, at least when the device is in its initial unexpanded resting state, as compared to presently available devices.
  • the provision of the fixation helix located/wound around the housing of the pacing device e.g., capsule
  • creates a structured surface which promotes and supports fibrotic tissue growth that can contribute towards the long-term attachment stability of the device inside the ventricle.
  • helical turns of the expandable section may be isolated by an insulating coverage, and at least one helical turn of the rigid section may be non-insulated to form a pacing electrode.
  • the distal portion of the fixation helix can be used as a pacing electrode, so that no additional pacing electrode and corresponding wiring is required.
  • the fixation helix may comprise at least two separated helical wire structures with respective helical turns that alternate in the axial direction of the fixation helix, wherein a first one of the helical wire structures comprises the rigid section, and wherein a second one of the helical wire structures comprises at least one non-insulated helical turn arranged proximal to the rigid section and forms a second pacing electrode.
  • two pacing electrodes can be provided on the fixation helix to allows for a dual pacing mode.
  • the expandable section may comprise a sub-section with a predetermined bending characteristic that (inherently) forces the pacing device towards the surface of the patient's tissue (to which the device is attached, such that the device rests substantially parallel against the septum wall) when the fixation helix has been screwed into the patient's tissue.
  • a predetermined bending characteristic that (inherently) forces the pacing device towards the surface of the patient's tissue (to which the device is attached, such that the device rests substantially parallel against the septum wall) when the fixation helix has been screwed into the patient's tissue.
  • the predetermined bending characteristic of the sub-section may be caused by a sectionally increased cross-sectional width of helical turns of the sub-section in the axial direction of the fixation helix.
  • the predetermined bending characteristic can be easily provided by forming helical turns with a desired shape, e.g., by a simple three-dimensional laser cutting process.
  • the sub-section may comprise helical turns with varying cross-sectional width in the radial direction of the fixation helix.
  • a pacing electrode may be provided at a distal end of the housing of the pacing device.
  • a proximal second pacing electrode can be provided for allowing a dual pacing mode.
  • an axially extending X-ray marker may be provided at a side portion of the housing of the pacing device.
  • the pacing device may be a leadless device for bundle branch pacing.
  • the size of the pacing device can be better adapted to individual space requirements in the RV of the patient.
  • the sub-section with the predetermined bending characteristic may be formed during manufacturing of the fixation helix by using a laser tube cutting process or thermal treatment to obtain the predetermined bending characteristic.
  • the predetermined bending characteristic can be easily controlled during the manufacturing of the fixation helix or the pacing device.
  • Fig. 1 shows schematically a heart in which respective placements of a lead device and a leadless device for ventricular trans-septal LBB pacing are schematically indicated;
  • Fig. 2 shows schematically a cross-sectional side view of a leadless device with an expandable fixation helix according to a first embodiment prior to penetration of the expandable fixation helix into the septum
  • Fig. 3 shows schematically a cross-sectional side view of a leadless device with the expandable fixation helix of Fig. 2 after penetration of the expandable fixation helix into the septum;
  • Fig. 4 shows schematically a cross-sectional side view of a leadless device with an expandable fixation helix according to a second embodiment with a multiple helix wire structure after penetration of the expandable fixation helix into the septum;
  • Fig. 5 shows schematically a cross-sectional side view of a leadless device with a pre-bent expandable fixation helix according to a third embodiment in a bent state after penetration of the expandable fixation helix into the septum;
  • Fig. 6 shows schematically a cross-sectional side view of a leadless device with an expandable fixation helix with longitudinally varying radial thickness according to a fourth embodiment after penetration of the expandable fixation helix into the septum.
  • a leadless medical pacing device e.g., capsule
  • expandable fixation helix e.g., expandable fixation helix
  • the present invention is particularly advantageous within the context of leadless pacing devices for transseptal pacing such as LBBP, the invention is not limited thereto and may also be used in connection with pacing leads and/or other pacing types and/or sites for other applications that require placement of a pacing device within a body tissue.
  • proximal and distal are terms that are used to indicate distances from an operating end (reference point) of the lead device, where the physician or other user controls the screwing process. Proximal is closer to the operating end, while distal is further away (at a greater distance) from the operating end.
  • leadless refers to a medical device (e.g., a pacing device) being devoid of any lead(s) extending out from it that is/are attachable to a patient's heart.
  • a medical device e.g., a pacing device
  • Some leadless devices may be introduced through a vein, but once implanted, such devices are free of, or may not include, any transvenous lead and may be configured to provide cardiac therapy without using any transvenous lead.
  • axial direction or length refers to the longitudinal axis of the pacing device.
  • Fig. 1 shows schematically a heart with an inserted lead device 200, where the pacing lead tip 20 is placed for ventricular transseptal LBBP. Additionally, for comparison reasons, a leadless device (capsule) 400 is shown prior to insertion of its helix 300 into the septum 24. Thereby, the LV can be paced from the RV by a ventricular transeptal approach.
  • the placement of the pacing lead tip 20 may be performed based on the procedure briefly explained above.
  • LBBP may be defined as capture of the LBB (i.e., left bundle trunk or its proximal fascicles), usually with septal myocardium capture at low output (e.g., ⁇ 1.0 V/0.4 ms).
  • the pacing lead tip 20 and the leadless device 400 are not intended to be used together. They can be used as alternatives depending on the situation/condition of the patient.
  • the heartbeat starts in the heart itself due to the sinoatrial node (SAN) which is found at the top (i.e., towards the neck/head region of the body) of the right atrium (RA) and sets the rate at which the heart contracts. It sends out electrical impulses that are carried through the muscular walls of both atria. These impulses cause atrial systole. The impulse is then passed to another node within the heart - the atrioventricular node (AVN). This node is in the lower part of the RA within the subendocardial layer of the heart wall of the interatrial septum that separates the RA from the left atrium (LA). Once the impulse from the SAN reaches the AVN, the impulse is passed to conducting fibers which travel down the central wall of the heart. The impulse then splits and travels up the LV and RV causing them to contract simultaneously (ventricular systole).
  • SAN sinoatrial node
  • RA right atrium
  • the His bundle travels in the sub-endocardium down the right side of the septum 24 for about 1cm before dividing into the LBB and RBB.
  • the LBB continues down the right side of the septum 24, while the LBB crosses to the left side and splits into anterior and posterior divisions.
  • excitation from the SAN controls the heart rhythm.
  • An abnormality in the sinus rhythm leads to arrhythmia, which refers to abnormalities in the rate, rhythm, site of origin, and conduction of the cardiac electrical pulse.
  • arrhythmia refers to abnormalities in the rate, rhythm, site of origin, and conduction of the cardiac electrical pulse.
  • ECG electrocardiogram
  • the pacing device for bundle pacing is a leadless device that does not use a lead to operably connect to an electrode disposed proximate to the septum when a housing of the device is positioned in the atrium.
  • the helix may be leadlessly coupled to the housing of the leadless device without using a lead between the electrode and the housing.
  • the leadless device i.e., an implemented medical pacing device
  • the leadless device may sense electrical signals attendant to the depolarization and repolarization of heart via the helix.
  • the leadless device may provide pacing pulses to the heart based on the electrical signals sensed within heart.
  • the configurations of electrodes at the helix used by the leadless device for sensing and pacing may be unipolar or bipolar.
  • the leadless device may also provide defibrillation therapy and/or cardioversion therapy via electrode(s), based on a detected arrhythmia of the heart, such as fibrillation of ventricles, e.g., by delivering a defibrillation therapy to the heart in the form of electrical pulses.
  • the leadless device may be programmed to deliver a progression of therapies, e.g., pulses with increasing energy levels, until a fibrillation of heart is stopped. To achieve this, the leadless device may detect fibrillation employing one or more fibrillation detection techniques known in the art.
  • the leadless device may comprise an intracardiac housing including a sensing circuit operably coupled to an electrode (i.e., the helix) and configured to sense one or both of an atrial event and a ventricular event using the electrode.
  • the housing of the leadless device my include an electrical pulse generator coupled to a bundle pacing electrode (i.e., the helix), the electrical pulse generator configured to generate and deliver electrical bundle-branch stimulation pulses based on one or both of atrial and ventricular events to the patient's heart using the bundle pacing electrode.
  • the housing of the leadless device may also include a communication interface configured to receive control signals.
  • the leadless device may further include a controller disposed in the housing and operatively coupled to the pulse generator to control delivery of bundle-branch pacing pulses to the patient's heart in response to the received control signals.
  • the leadless device may be programmed by a handheld computing device or a computer workstation or a mobile phone, which may include a user interface that receives input from a user.
  • the user interface may include, for example, a keypad and a display, which may for example, be a cathode ray tube (CRT) display, a liquid crystal display (LCD) or light emitting diode (LED) display.
  • the keypad may take the form of an alphanumeric keypad or a reduced set of keys associated with particular functions.
  • a peripheral pointing device such as a mouse or a touchscreen, may be provided, via which a user may interact with the user interface.
  • a user may select one or more optimized parameters, e.g., AV delay and/or VV delay.
  • Fig. 1 indicates an exemplary location for an implantation of a leadless device 400 for LBBP, prior to the insertion of its helix 300 into the septum 24.
  • the required angulation/position prior to puncturing the septum 24 is not achievable, since the total length of the leadless system (leadless pacing device 400 with its permanently protruding helix 300) is not compatible with the normal anatomy of the patient's heart. Implantation may thus cause too much interaction with the (free) wall of the RV. This will lead to a huge interference between the leadless device 400 and the tricuspid valve which is located between the heart's two right chambers (RVs).
  • the tricuspid valve consists of three thin flaps of tissue (called cusps, or leaflets). These valve flaps open to let blood flow from the upper right chamber of the RV to the lower right chamber of the RV.
  • the above non-compatible dimensions may also seriously penalize the implantation procedure or even may not permit the implantation of the leadless device 400 at the desired site.
  • the total rigid length of the leadless device 400 may not be compatible with the flexibility required for the delivery system to navigate through a desired blood vessel (e.g., a tortuous vein).
  • the following embodiments of the proposed pacing device are configured to minimize any adverse impact of placement and insertion of the lead device at/through the septum (e.g., to facilitate feeding of the lead device and reduce mechanical interactions e.g. with the tricuspid leaflet) by providing an expandable fixation helix that expands during the screwing process and/or is bendable after insertion to thereby address and mitigate the above problems.
  • Fig. 2 shows schematically a cross-sectional side view of a leadless device (capsule (CP)) 40 with a long expandable fixation helix 30 according to a first embodiment prior to penetration of the expandable fixation helix into the septum 24.
  • CP leadless device
  • a permanent firm connection (e.g., by welding, crimping etc.) may be established.
  • a non-movable/non-expandable proximal extremity of the helix 30 may be mechanically fixed to the housing of the leadless device 40 and may then be connected to internal electronic circuitry, e.g., via a feed-through technology which may also ensure hermetical sealing of the housing.
  • the expandable fixation helix 30 is mounted over (e.g., slipped on, pushed on, its turns are wound around or wrapped around) the cylindrical housing (body) of the leadless device 40.
  • the overall length of the leadless device 40 including the expandable fixation helix 30 can be substantially reduced prior to insertion of the helix 30 into the septum 24, so that less space is required during placement.
  • the expandable fixation helix 30 includes a first section (SI) of at least one helical turn 34 with a non-elastic geometry or characteristic (at least in the axial direction of the helix 30), an opened gap (distance) between the helical turns 34 and sharpened extremity (not shown) for easy puncturing of the heart tissue at the septum 24 of the patient's heart.
  • the length of the first section may range from 0.5 to 3 mm.
  • the first section is thus configured to achieve engagement (puncturing, engagement) of the tip portion of the expandable fixation helix 30 with the heart tissue and advancement of the expandable fixation helix 30 through the septum wall and into the septum tissue through a screwing process.
  • the first section may thus be made of a rigid material to avoid deformation of the helix during screwing.
  • the helical turns 34 of the first section are not insulated by any non-conductive coverage or isolation.
  • the surface of the helical turns 34 of the first portion may be coated with classic TiN (Titanium nitride). It is noted that the expandable fixation helix 30 may optionally be made of two different materials.
  • the distal first section (SI) may be made of classic platinum-iridium (Pt-lr) 90/10 or 80/20, as the first section (SI) is intended to act as an electrode (cathode) which may need surface coating (e.g., TiN) to optimize the electrical performances.
  • the distal first section (SI) may be configured to provide X-ray visibility to help the physician to precisely locate the cathode within the width of the septum 24.
  • the expandable fixation helix 30 includes a longer second section (S2) with an elastic characteristic (at least in the axial direction of the helix 30), which is configured to be firmly connectable to the leadless device 40 at its proximal extremity to ensure permanent and reliable electrical connection to a pacing output of the leadless device 40.
  • the length of the second section may range from 4 to 25 mm.
  • the helical turns 32 of the second section may include an insulated surface (indicated in Fig. 2 as a bold covering of the cross section of the helical turns 32) to prevent a non-desired an electrode functionality in this embodiment.
  • the insulated surface may be achieved by covering the helical turns 34 by a dielectric or other insulative material.
  • the second section of the expandable fixation helix 30 may be made from an elastic material such as Nitinol to sustain a high level of elastic deformation and fatigue resistance and allow for X-ray visibility.
  • the leadless device 40 may comprise an additional RV cathode (CRV) implemented as a conducting electrode 50 placed on (e.g., mounted at or integrated into) the housing of the leadless device 40 at the distal front for independent LV/RV pacing and controlling a delay between stimulation of both chambers.
  • RV RV cathode
  • the expandable fixation helix 30 may be made using e.g. laser tube cutting to allow a "wire" structure of the helical turns 32 with variable cross section wire along the helix structure.
  • Laser tube cutting is a process and technique used to cut tubes, structural shapes, or channels. The process will cut these items to the length needed. It can also cut out holes or designs in the tubing. It is a precise cutting technique. It can also be used on a wide variety of materials in all shapes and sizes. Laser tube cutting equipment comes in a variety of types that can handle different cutting needs. A 3-axis laser tube cutter cuts in three dimensions.
  • the expandable fixation helix 30 may be made using classic coiling of one or more insulated wires (as used e.g. for inner conductors of lead devices with a coiling of 4 to 6 individual wires).
  • the above-mentioned variable cross section enables easier firm and permanent connection between the proximal extremity or end of the expandable fixation helix 30 and the pacing output of the leadless device 40.
  • Fig. 3 shows schematically a cross-sectional side view of the leadless device 40 with the expandable fixation helix 30 of Fig. 2 after penetration of the expandable fixation helix 30 into the septum 24.
  • Fig. 3 shows the LV cathode (CLV) formed by the helical turn(s) 34 of the nonexpandable first section of the expandable fixation helix 30 that has reached the pacing area for LBBP.
  • CLV LV cathode
  • This is achieved through the expansion (elongation) of the second section S2 in the axial direction during advancement of the expandable fixation helix through the septum (S) 24 by a screwing motion, wherein the helical turns 32 of the second section of the expandable fixation helix 30 are configured to slide distally in the axial direction over the surface of the housing of the leadless device 40.
  • an extra safety insulation layer can be added onto the housing of the leadless device 40 to reinforce the electrical insulation and increase the abrasion resistance of the housing.
  • a variable cross section wire can be created along the helical structure of the expandable fixation helix 30.
  • an optional full cylinder structure 38 can be created. Thereby, proper electrical connection to the pacing output terminal of the leadless device 40 can be provided.
  • the laser tube cutting process can be controlled to create a variable cross section wire along the helical structure of the expandable fixation helix 30 to obtain two sub-sections S2b and S2a of the elastic second section with different bending characteristics, as explained later in more detail in connection with Fig. 5.
  • Fig. 4 shows schematically a cross-sectional side view of a leadless device 40 with an expandable fixation helix 30 according to a second embodiment with a multiple helix wire structure after penetration of the expandable fixation helix into the septum 24.
  • the multiple helix wire structure can be made using e.g. the laser tube cutting process and comprises at least two coiled/helical wires of same diameter that form the expandable fixation helix 30.
  • first helical turns 32 of a first helical wire and second helical turns 36 of a second helical wire are alternately and slidably wound around the housing of the leadless device 40.
  • the distal end portion of the first helical wire is connected to the non-expandable first section of the expandable fixation helix 30 with the at least one non-insulated helical turn 34 that forms the LV cathode (CLV).
  • CLV LV cathode
  • the distal end portion of the second helical wire with helical turns 36 is connected to at least one expandable and non-insulated helical turn 35 that forms an RV cathode (CRV).
  • RV cathode a RV cathode
  • two electrodes LV cathode and RV cathode
  • LV cathode and RV cathode can be embedded or integrated in the expandable fixation helix 30.
  • the elastic second section of the expandable fixation helix 30 may comprise at least two sub-sections S2a and S2b of different bending characteristics.
  • Fig. 5 shows schematically a cross-sectional side view of a leadless device 40 with a pre-bent expandable fixation helix 30 according to a third embodiment in a bent state after penetration of the expandable fixation helix 30 into the septum 24.
  • the exemplary laser tube cutting process allows creation of a variable cross section of the helical wire along the structure of the expandable fixation helix 30.
  • different predetermined bending characteristics can be created in sub-section 2a and 2b of the expandable fixation helix 30, allowing the leadless device 40 to lay/rest onto or at the wall of the septum 24 at the RV with its central axis parallel to the plane of the surface of the septum.
  • the housing of the leadless device 40 no longer interacts with the tricuspid pillars and/or leaflets after placement of the leadless device 40 and insertion of the expandable fixation helix 30.
  • Fig. 5 depicts a position that the leadless device 40 may adopt post attachment / tissue penetration.
  • a substantial portion of the helical turns 32 of the flexible second section will no longer be located around the housing of the leadless device 40, as they will have axially moved/slipped off the housing in a distal direction, thus freeing a substantial portion of the second sub-section S2b of the expandable fixation helix 30 from the housing.
  • this second sub-section S2b is configured to have a predetermined (inherent) bending characteristic, it aids to rotate the longitudinal axis of the device housing towards the surface of the septum (S), which may be a rotation of about 90 degrees.
  • Fig. 5 also depicts a way of achieving this predetermined (inherent) bending characteristic or property of the second sub-section S2b, wherein one side of the distal portion of the second sub-section S2b that forms the outside boundary of the intended bend has a longer cross section (LCS) in the axial direction than its counterparts forming the inside boundary of the intended bend.
  • LCS cross section
  • the predetermined bending characteristics may also be achievable by predetermined thermal treatment of predetermined portions of the section sub-section S2b of the expandable fixation helix 30.
  • the placement of the leadless device 40 with the bent state/orientation close to (parallel to) the septum wall may be advantageously used for placing a sectional electrode pattern 60 as RV cathode (CRV) at a side portion of the proximal end of the leadless device 40, which contacts the septum wall of the RV when the expandable fixation helix 30 is in said bent state.
  • RV cathode RV cathode
  • the pacing surface of the sectional electrode pattern 60 can be reduced (e.g., half peripheral section) because the contact point after the act of bending is predetermined.
  • the placement of the leadless device 40 in the bent state provides a further advantage in that the turns of the fixation helix 30 are twisted/wound around the housing of the leadless device 40 creates a structured surface which can support fibrotic tissue growth.
  • fibrotic tissue growth around the leadless device 40 will be promoted faster and stronger due to the tissue reaction being enforced by the intermittent physical contact (due to beating of the heart) of the leadless device 40, which will create a better fixation of the leadless device 40 at the tissue of the heart (e.g., septum). More specifically, fibroblasts and other cells deposit components of the extracellular matrix, such as collagen, form a 'scar' over the damaged area.
  • an axially elongated X-ray marker 70 of an X-ray-detectable material may be provided at (e.g., attached to or integrated in) the housing of the leadless device 40 at to indicate the bending direction of the leadless device 40 e.g. before releasing the leadless device 40 from a delivery catheter used for placement of the leadless device in the RV. It is noted that the axially elongated X-ray marker 70 could as well be provided in the other embodiments to indicate the axial direction of the leadless device 40 after placement.
  • the role of the X-ray marker could be achieved by the sectional electrode pattern 60 as well, so that the X-ray marker 70 could be dispensed with.
  • Fig. 6 shows schematically a cross-sectional side view of a leadless device 40 with an expandable fixation helix 30 with longitudinally varying radial thickness according to a fourth embodiment after penetration of the expandable fixation helix into the septum 24.
  • the second sub-section S2b of the expandable fixation helix 30 may comprise helical turns 32, 33 with different cross-sectional widths in the radial direction R of the leadless device 40.
  • a proximal portion of the second sub-section S2b comprises first helical turns 33 with larger radial width
  • a distal portion of the second sub-section S2b comprises second helical turns 32 with smaller radial width to thereby achieve desired mechanical properties along the expandable fixation helix 30.
  • the expansion rate of the proximal portion would be less than that of the distal portion, so that the axial length of the leadless device 40 could be reduced to reduce space requirements within the RV.
  • the puncturing process may be facilitated due to a restraining effect provided by a thicker cross-sectional width along the second sub-section S2b, which shortens the section that can be easily inserted into the septum.
  • the spring effect of the second sub-portion S2b may be increased (or decreased) to maintain physical contact of the RV cathode (CRV) with the tissue on the RV side.
  • variable radial cross sections of the helical turns along the axial direction may also be feasible (e.g., achieved by laser tube cutting with an original tube with multiple outer diameters along its axial length) to reach different mechanical properties along the expandable fixation helix 30.
  • the housing of the leadless device 40 may be made with plastic material like polyetheretherketon (PEEK) due to its high biocompatible properties and extremely rigid mechanical structure.
  • the housing of the leadless device 40 may be made of titanium (to achieve e.g. X-ray transparency, weldability, desired mechanical and biological properties etc.) and coated with an insulation coating like parylene or ethylene tetrafluoroethylene (ETFE).
  • PEEK polyetheretherketon
  • ETFE ethylene tetrafluoroethylene
  • a pacing device e.g., including but not limited to a leadless device
  • a fixation helix for fixing the pacing device at a patient's tissue
  • the fixation helix comprises an expandable portion that extends when the fixation helix is screwed into the tissue, to thereby reduce the space required during insertion and allow a placement of the pacing device in a bent state for minimal unwanted mechanical interaction.
  • the fixation helix may have a non-symmetrical configuration around its longitudinal axis, e.g., with respect to its circumferential shape and/or the cross-section of its turnings.
  • the width of the turns may be thinner on one side than on the opposite side.
  • Suitable designs of lead devices may have a multi-lumen, coaxial and coradial structure, both as tachycardia leads or bradycardia leads, and a central lumen for a stylet passage may be provided.
  • Coaxial leads have an inner conductor that extends down the length of the lead to the tip electrode (helix), the cathode, arranged in a coil configuration that provides a central lumen e.g. to allow for passage of a stylet at implantation.
  • Coradial bipolar leads address some of the disadvantages of coaxial leads with respect to the bulk and stiffness of their four-layer design, by providing a new conductor and insulator technology where a single coil extends down the length of the lead (again with a central lumen to allow for stylet insertion) and consists of two parallel, alternating conductor strands, one of which connects to the cathode and the other to the anode.
  • Each conductor strand may be individually coated with a bonded layer of e.g. ethylene tetrafluoroethylene (ETFE) fluoropolymer insulation that serves to insulate each strand from the other, despite being intertwined.
  • ETFE ethylene tetrafluoroethylene
  • the single, two-component coil may be surrounded by a single, outer insulation covering.
  • the multi-lumen or coaxial or coradial leads may optionally comprise a fixed, non-retractable helix to minimize size.
  • a retractable helix may also be used in connection with the described embodiments.
  • the proposed lead system may be configured to provide improved torquability, i.e., an ability to transmit torque safely and accurately to the helix (e.g., full lead body torque) and stylet-driven compatibility to ease the handling (e.g., by push transmission).
  • improved torquability i.e., an ability to transmit torque safely and accurately to the helix (e.g., full lead body torque) and stylet-driven compatibility to ease the handling (e.g., by push transmission).
  • a coradial lead with compatible screwing stylet screwing stylet
  • the proposed lead device with expandable fixation helix may be configured to be adapted or adaptable to IS1, IS4 (low voltage) or DF4 (high voltage) connectors.

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Abstract

L'invention concerne un dispositif de stimulation (par exemple, une capsule sans fil) qui comprend une hélice de fixation distale pour fixer le dispositif de stimulation au niveau du tissu d'un patient, l'hélice de fixation comprenant une partie extensible qui s'étend lorsque l'hélice de fixation est vissée dans le tissu, pour ainsi réduire l'espace requis pendant l'insertion et permettre un placement du dispositif de stimulation dans un état plié pour une interaction mécanique non désirée minimale.
PCT/IB2023/000182 2023-04-06 2023-04-06 Hélice de fixation extensible pour fixation d'électrode Pending WO2024209225A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN202380097838.4A CN121057603A (zh) 2023-04-06 2023-04-06 用于电极固定的可扩展固定螺旋体
PCT/IB2023/000182 WO2024209225A1 (fr) 2023-04-06 2023-04-06 Hélice de fixation extensible pour fixation d'électrode

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/IB2023/000182 WO2024209225A1 (fr) 2023-04-06 2023-04-06 Hélice de fixation extensible pour fixation d'électrode

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WO2024209225A1 true WO2024209225A1 (fr) 2024-10-10

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11338145B2 (en) * 2018-01-17 2022-05-24 Cardiac Pacemakers, Inc. Current steering to achieve spatial selectivity for his bundle pacing
US11351385B2 (en) * 2017-09-14 2022-06-07 Sorin Crm Sas Attachment means for implantable cardiac device
US11464987B2 (en) * 2019-11-19 2022-10-11 Cardiac Pacemakers, Inc. Implantable medical device and delivery catheter apparatus system and method

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11351385B2 (en) * 2017-09-14 2022-06-07 Sorin Crm Sas Attachment means for implantable cardiac device
US11338145B2 (en) * 2018-01-17 2022-05-24 Cardiac Pacemakers, Inc. Current steering to achieve spatial selectivity for his bundle pacing
US11464987B2 (en) * 2019-11-19 2022-10-11 Cardiac Pacemakers, Inc. Implantable medical device and delivery catheter apparatus system and method

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