Cut helix for lead fixation

Abstract

The present invention relates to a lead device including a distal fixation helix for anchoring the lead tip in a patient's tissue (e.g., cardiac tissue, particularly septal tissue). The fixation helix includes a cutting portion for cutting tissue circumferentially about the fixation helix when the fixation helix is ​​screwed into the tissue, in addition to puncturing the tissue with the distal end of the fixation helix (30). This supports longitudinal insertion of the lead tip having the fixation helix into the tissue. This facilitates and smooths insertion and longitudinal advancement of the lead tip into the tissue by pre-cutting the tissue circumferentially at and / or around and / or within the fixation helix during the screwing operation into the tissue.

Description

[Technical Field]

[0001] The present invention relates to the field of, but is not limited to, fixation structures for lead devices (e.g., electrode catheters) for cardiac pacing systems such as left bundle branch pacing (LBBP), cardiac resynchronization, or tachycardia ("tachy") systems. [Background technology]

[0002] Different electrical activation sequences in cardiac pacing can have different consequences on the mechanical pumping efficiency of the stimulated heart. Optimal pumping efficiency requires rapid and uniform contraction of the ventricles.

[0003] Traditional pacing sites, such as the right ventricular apex (RVA), may provide stable lead positioning at low displacement rates but are less effective at optimizing left ventricular (LV) contraction (which accounts for approximately 80% of the cardiac mass). Chronic RVA pacing can adversely affect left ventricular function by inducing iatrogenic left bundle branch block (LBBB), which can have profound effects on left ventricular hemodynamics. This observation led to a reevaluation of traditional approaches and the investigation of alternative pacing sites to achieve more physiologic ventricular activation patterns and avoid adverse effects.

[0004] LBBP has emerged as an alternative method of physiological pacing to achieve LV electrical synchrony, particularly in patients with infranodal atrioventricular block and / or LBBB. The proximal LBBB passes through the LV septum and fan-out, providing a wider pacing target compared with the His bundle. LBBP techniques using the transseptal approach (i.e., pacing the LV from the RV) have been developed. LBBP has been reported to have a low pacing threshold and large R waves, and because it targets the distal conduction system, there is a theoretically low risk of distal conduction block.

[0005] After determining the initial site of LBBP location on the right surface of the ventricular septum, the pacing lead (i.e., the helical fixation element or electrode at the lead tip) is screwed into the left ventricular (LV) septum, for example, by puncturing the tissue with the distal tip of the helical fixation element (fixation helix). The depth of the LBBP lead into the LV septum can be determined by observing changes in the V1 lead notch, sheath angiography, the fulcrum sign, and / or impedance monitoring. The pacing lead is slowly advanced with torque to the determined depth (e.g., approximately 6–8 mm) while avoiding septal perforation. Finally, LBB capture is confirmed based on acceptable pacing parameters. This confirmation can be based on at least one of the following: the morphology of the RBBB pattern after pacing, recording of LBB potentials, LVAT stimulation peaks that shorten rapidly with increasing output or remain shortest and constant at low and high outputs, selective and non-selective LBBP, recording of retrograde His potentials or orthodromic LBB potentials during pacing.

[0006] Common features of the implantation or placement process include transvenous access, transseptal placement of the pacing lead into the left ventricular (LV) septal subendocardium in the LBB region, and confirmation of LBB capture.

[0007] The tips of pacing or tachycardia leads are typically designed to avoid the risk of septal perforation. They may also be equipped with a soft tip (e.g., made of silicone) to increase the stopping surface. That is, when a helical fixation element or electrode (hereinafter referred to as a "helix") engages (e.g., screws into) (cardiac) tissue, the tissue presses against the soft tip, preventing the helix from rotating and advancing further through the tissue. The length of the helix may be limited to an effective length of, for example, about 2 mm.

[0008] However, the challenge with the puncture process in the septum or other tissues lies in optimizing the helix's advancement performance with respect to the energy / force required for puncture and designing a lead that allows for controlled and safe advancement without increasing the lead's complexity. To do so, it must be kept in mind that the inner surfaces of the RV and LV cavities are "covered" with a thin, tough skin (membrane or lining) called the "endothelium." This means that the endothelium is much more difficult to puncture than the inner part of the septum. Summary of the Invention

[0009] SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrode catheter system that addresses the above-mentioned problems encountered in connection with LBBP or other pacing methods and improves the efficiency of the puncture process.

[0010] This object is achieved by a fastening element according to claim 1.

[0011] The proposed lead device includes a lead tip, which includes a distal fixation helix for fixing the lead tip to a patient's tissue (e.g., cardiac tissue, particularly septal tissue), and the fixation helix is ​​provided with a cutting portion for cutting tissue circumferentially (circumferentially) around the fixation helix in addition to puncturing it with the distal tip when the fixation helix is ​​screwed into tissue, thereby supporting longitudinal insertion of the lead tip having the fixation helix into tissue.

[0012] Therefore, by pre-cutting the tissue circumferentially at and / or around and / or within the fixation helix during the screwing operation into tissue, the insertion and longitudinal advancement (movement) of the lead tip into the tissue is facilitated and smoothed.

[0013] According to a first option, the cutting portion can include two adjacent turns of the fixation helix with a closed intermediate gap in the longitudinal direction between the two adjacent turns. During the act of screwing the fixation helix into tissue, the tissue is tightly compressed between the two adjacent turns with the closed gap, resulting in a scissors-like cutting effect in the circumferential direction of the fixation helix. This allows for a simple and cost-effective realization of an additional cutting effect.

[0014] According to a second option, which can be combined with the first option, two adjacent turns of the fixation helix can be provided on the proximal portion of the fixation helix, such that the distal portion of the fixation helix serves to aid in longitudinal advancement of the lead device via a threading operation.

[0015] According to a third option, which can be combined with the first or second option, at least one of two adjacent turns of the fixation helix can include a cross-sectional shape with a sharp edge toward the opposite adjacent turn, such that the sharp edge increases pressure on the tissue and provides a better cutting effect.

[0016] According to a fourth option, which can be combined with any of the first through third options, a conical insert can be secured to the distal end of the lead tip and surrounded by the fixation helix, the conical insert compressing tissue within the fixation helix outward toward the adjacent cutting turn during longitudinal advancement, thereby increasing the cutting area and facilitating insertion of the lead tip into tissue.

[0017] According to a fifth option, which can be combined with any of the first through third options, a conical screw can be fixed to the distal end of the lead tip and surrounded by a fixation helix. The conical screw presses tissue within the fixation helix outward toward the adjacent cutting turn during longitudinal advancement, thereby increasing the cutting area and facilitating insertion of the lead tip into the tissue. Furthermore, the conical screw supports longitudinal advancement by its surface threads.

[0018] According to a sixth option, which can be combined with any of the first to third options, the cutting portion can include a cutting wire (or other filament or thin rod) disposed between adjacent turns of the fixation helix. During the operation of screwing the fixation helix into tissue, the tissue is cut circumferentially by the cutting wire as the fixation helix rotates. This ensures an additional cutting effect.

[0019] According to a seventh option, which can be combined with any of the first to third options, the cutting portion can include a blade element disposed within the fixation helix. During the operation of screwing the fixation helix into tissue, the tissue is cut in the circumferential direction of the fixation helix by the inner blade. This can further reliably achieve an additional cutting effect.

[0020] According to an eighth option, which can be combined with any of the first to sixth options, the lead tip can include a first electrode formed by a fixation helix and an inter-electrode section between the fixation helix and the proximal anode, such that the inter-electrode section can be designed according to the requirements of the puncture process.

[0021] According to a ninth option, which can be combined with the eighth option, the ratio of the first outer diameter of the fixation helix to the second outer diameter at the distal end of the inter-electrode portion is set between 0.8 and 1, the first outer diameter is set between 1 and 1.8 mm, the lead tip length is set between 8 and 15 mm, and the fixation helix length is set between 1.5 and 5 mm, thereby allowing the dimensions of the lead tip to be designed to facilitate insertion of the lead tip into tissue during the puncture process.

[0022] According to a tenth option, which can be combined with the eighth or tenth option, the inter-electrode portion (between the proximal end of the helix and the distal end of the anode) can have a conical shape, which facilitates insertion of the lead tip into tissue during the puncture process.

[0023] According to an eleventh option, which can be combined with any of the first through tenth options, the body of the lead device can have a core-radial structure, which reduces the bulk and stiffness of the lead device and makes it easier to insert the lead tip, including the fixation helix, into tissue.

[0024] According to a twelfth option, which can be combined with any of the first through eleventh options, at least the distal end of the lead tip housing, surrounding the proximal end of the fixation helix, is tapered to provide a sharp leading edge that acts as a complementary axial cutting portion, thereby further supporting the puncture procedure with a complementary cutting effect.

[0025] It will further be understood that a preferred embodiment of the invention may also be any combination of the dependent claims or the above embodiments with the respective independent claim.

[0026] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter. [Brief explanation of the drawings]

[0027] [Figure 1] 1 shows a schematic representation of a heart with a lead device placed for ventricular septal trans-LBB pacing. [Figure 2] 1A and 1B are schematic side views of a lead tip including a conventional fixation helix; [Figure 3A] 1A and 1B schematically illustrate a cross-sectional view of a lead tip including a truncated helix according to one embodiment prior to penetration of the lead tip into the septum. [Figure 3B]3B shows a schematic cross-sectional view of the lead tip including the truncated helix of FIG. 3A after the lead tip has penetrated the septum. [Figure 4] 10A and 10B show schematic side views of a more detailed example of a lead tip including a truncated helix, with the lead tip housing partially cut away. [Figure 5] 10A and 10B schematically illustrate a cross-sectional view of a lead tip including a cutting helix and a conical insert according to another embodiment. [Figure 6] 10A and 10B schematically illustrate cross-sectional views of a lead tip including a cut helix and a conical thread according to a further embodiment; [Figure 7] 10A and 10B schematically illustrate cross-sectional views of a lead tip including a cutting helix and a single-sided sharp cutting portion according to a further embodiment. [Figure 8] 10A and 10B schematically illustrate cross-sectional views of a lead tip including a cutting helix and a double-sharp cutting portion according to a further embodiment. [Figure 9] 10A and 10B are schematic perspective views of a lead device including a fixation helix including a cutting wire, according to a further embodiment; [Figure 10] 10A and 10B are schematic diagrams illustrating a perspective view of a lead device including a fixation helix surrounding an internal cutting blade according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0028] Various embodiments of the present invention are described below based on an improved lead device (e.g., electrode catheter) that includes a fixation helix. While the present invention is particularly advantageous in the context of transseptal pacing, such as LBBP, the invention is not limited thereto and may be used in combination with other pacing types and / or sites in other applications requiring placement of a lead device within body tissue.

[0029] It should be noted that throughout this disclosure, the accompanying drawings only show elements, parts, components, and / or devices related to the proposed lead device and deployment procedure. Other elements, parts, components, and / or devices are omitted for the sake of brevity. Furthermore, components designated with the same reference numeral or number are intended to have the same or at least similar functionality, and therefore, their functionality will not be described again below.

[0030] Additionally, throughout this disclosure, "proximal" and "distal" are terms used to refer to the distance from the operating end (reference point) of the lead device where the physician or other user controls the screwing process, with proximal being closer to the operating end and distal being further away from the operating end.

[0031] FIG. 1 shows a schematic diagram of a heart with a lead device 200 inserted, with the pacing lead tip 20 positioned for ventricular septal LBBP, which allows pacing of the RV from the LV via a ventricular septal approach as a guide for catheter insertion. The placement of the pacing lead tip 20 can be performed based on the procedures described above. LBBP can be defined as capture of the LBB (i.e., the left bundle trunk or its proximal bundle), typically capturing the septal myocardium with low power (e.g., <1.0 V / 0.4 ms).

[0032] In normal cardiac function, the heart beat is initiated within the heart by the sinoatrial node (SAN) at the top of the right atrium (RA), which determines the rate at which the heart contracts. The SAN sends out electrical impulses that are transmitted through the muscular walls of both atria. These impulses cause atrial contraction. The impulses then travel to another node within the heart, the atrioventricular node (AVN), located at the bottom of the right atrium (RA). When the impulse from the sinoatrial node (SAN) reaches the atrioventricular node (AVN), it is transmitted to conduction fibers that travel down the central wall of the heart. The impulse then branches and travels up the left ventricle (LV) and right ventricle (RV), which contract simultaneously (ventricular systole).

[0033] Important elements of the cardiac conduction system reside within the interventricular septum 24. The bundle of His travels through the subendocardium for approximately 1 cm along the right side of the septum 24, where it bifurcates into the LBB and RBB. The LBB (RBB) continues along the right side of the septum 24, where it crosses to the left side and bifurcates anteriorly and posteriorly.

[0034] Under normal conditions, cardiac rhythm is controlled by excitation from the sinoatrial node (SAN). Abnormal sinus rhythms can lead to arrhythmias. Arrhythmia refers to abnormalities in the rate, rhythm, site of origin, and conduction of the heart's electrical impulses. When specific conduction fibers within the ventricles are damaged, the repolarization wave must then travel along slower intermuscular pathways to reach the ventricles. Typical disorders associated with pathologies involving different conducting bundle branches include LBBB and RBBB. An electrocardiogram (ECG) obtained from an implanted lead device can be used to measure and record the heart's electrical activity, thus providing important information about cardiac function. The ECG has been used as a standard diagnostic tool for analyzing arrhythmias.

[0035] The following embodiments of the proposed lead device are configured to minimize the adverse effects of inserting the lead device through the septum 24 (e.g., to prevent permanent arterial damage) by minimizing the puncture area and / or incorporating a cutting mechanism including an improved fixation helix.

[0036] The body of the lead device may be configured to improve slipperiness with a guide catheter used to navigate the lead device (e.g., through a blood vessel) to a target area. This may be achieved, for example, by using a reduced diameter polyurethane (PU) material to reduce the effort required to advance the lead body through the guide catheter and the lead tip 20 through the septum 24.

[0037] Suitable lead device designs, whether for tachycardia or bradycardia, can include multilumen, coaxial, and coradial configurations, and can provide a central lumen for passage of a stylet. Coaxial leads have an inner conductor that runs along the length of the lead to a cathode, which is a tip electrode (helix) arranged in a coil configuration that provides a central lumen for passage of, for example, a stylet during implantation.

[0038] Co-radial bipolar leads address some of the drawbacks of coaxial leads, such as the bulk and stiffness of their four-layer design, through a novel conductor-insulator technology. In this technology, a single coil extends the length of the lead (also containing a central lumen to allow for stylet insertion) and consists of two parallel, alternating conductor strands, one of which is connected to the cathode and the other to the anode. Each conductor strand can be individually coated with an adhesive layer, such as ethylene tetrafluoroethylene (ETFE) fluoropolymer insulation, which serves to insulate the strands from each other despite their intertwined nature. The single, two-element coil may be surrounded by a single outer insulating cover.

[0039] Multilumen, coaxial, or coradial leads may optionally include a fixed, non-telescopic helix to minimize size, although telescoping helices may also be used in conjunction with the described embodiments.

[0040] Additionally, the proposed lead system can be configured to provide improved torque transmission, i.e., the ability to safely and accurately transmit torque to the helix (e.g., torque throughout the lead body), and stylet-driven compatibility (e.g., via push-to-drive) for ease of handling. In one example, a core radial lead can be provided that includes a compatible screw-in stylet (screw-driven stylet).

[0041] 2 schematically illustrates a side view of a lead tip 20 including a conventional fixation helix 30 having an effective length L, which is threaded into cardiac tissue by simply puncturing the tissue with the distal tip of the fixation helix 30. The lead device can be used for stimulation of the left and / or right bundle branches. The lead device can include an elongate body extending between a proximal end (not shown) configured for connection to, for example, an implantable pulse generator, and the distal end of the fixation helix 30. The elongate body can also include a lumen extending between the proximal and distal ends.

[0042] In at least some of the following embodiments, with regard to the design of the distal end (distality) of the lead device, the ratio of the outer diameter of the helix 30 to the outer diameter of the housing of the lead tip 20 may be greater than 70%, ideally 100%, and an equal profile distality may be provided to avoid an anterior stop surface for better insertion.

[0043] Additionally, the helix 30 may be made of a rigid material to avoid deformation of the helix during screwing, while a fixed helix (i.e., a lock between the helix 30 and the lead body) can simplify handling (i.e., no parasite tools are required for a retractable system).

[0044] Additionally, adapting the distance between the fixed helix and the proximal second cathode for bilateral pacing provides design flexibility to accommodate different septal thicknesses in different individuals.

[0045] The distal design of the lead device can be further configured to allow the lead tip 20 to be smoothly and predictably advanced into the septum until the helix (cathode) 30 reaches the desired location in the left ventricle (LV), i.e., near the LBB without completely perforating the septum, so that the helix 30 does not protrude into the left ventricle (LV).

[0046] Additionally, the lead device design can be configured to minimize the energy / torque required to perform septal puncture, for example, by providing a specialized distal tapered lead tip 20 with a conical shape in the interelectrode section (between the proximal helix end and the distal anode end).

[0047] In some cases, at least a proximal portion of fixation helix 30 may be insulated, while at least one turn at the distal end of fixation helix 30 may be uninsulated. One or more turns of fixation helix 30 (e.g., inside the lumen of the elongate body) may be covered with a dielectric or other insulating material. Removing the proximal portion or turn of fixation helix 30 may minimize impedance interference that may result from the spacing between the proximal electrode (not shown) and fixation helix 30.

[0048] The fixation helix 30 can be attached (e.g., welded) to a driver (not shown). The driver may include a circumferential coil or other non-planar, regular or irregular surface structure, ensuring good adhesion between the driver and the surrounding material of the lead body in the inter-electrode region (between the proximal helix end and the distal anode end), resulting in a simple, rigid, and durable lead tip 20 structure with fewer parts and improved long-term reliability. The driver is fixedly supported on the lead body and includes a threaded stylet function that is mechanically and electrically connected to a matching threaded stylet adapter for insertion of the mating end (engagement portion) of a separate threaded stylet, allowing the helix to be rotationally driven via the driver. The electrical connection between the fixation helix 30 and the threaded stylet allows electrical signals sensed by the fixation helix 30 at the target area to be transmitted via the threaded stylet to a signal analyzer, which can be used to monitor proper placement of the fixation helix 30 without cutting during the threading operation, enabling one-step operation.

[0049] The conical shape of the lead tip 20 can be determined based on dimensional parameters, for example, the outer diameter Da of the proximal anode, the outer diameter DI of the distal section of the lead tip 20, the outer diameter Dh of the fixation helix 30, the length L of the fixation helix 30, and the overall length Lt of the lead tip 20, including the fixation helix 30 and the tapered portion of the lead body (e.g., surrounding the driver) between the fixation helix 30 and the proximal anode.

[0050] In an example, the Dh / DI ratio can be set between 0.8 and 1, Dh can be set between 1 and 1.55 mm (preferably 1.40 mm), Da can be set between 1.25 mm and 1.94 mm (preferably 1.66 mm), Lt can be set between 8 and 15 mm, and L can be set between 2 and 5 mm.

[0051] This particular cone shape proposed in the above size range allows a lead tip including a fixed helix 30 to penetrate tissue in a target area in a controlled and smooth manner, providing a cone profile that minimizes the energy required to effect the penetration.

[0052] In the following embodiments, the structure of the fixation helix is ​​enhanced by providing an additional cutting function that cuts tissue circumferentially around the helix when torque is applied to the lead tip, facilitating and smoothing translation (longitudinal movement) of the lead tip and helix during the rotational puncture process. This results in a cutting helix. More specifically, the cutting portion or cutting element of the cutting helix is ​​configured to locally incise tissue located within, on, or around the cutting helix and / or enlarge a tissue opening for the lead tip body while the cutting helix rotates and moves longitudinally through the tissue. As a result, when the cutting helix is ​​screwed into tissue, the rotational drilling or puncture process by the tip at the distal end of the cutting helix is ​​supported by an additional circumferential cutting process, thereby significantly reducing the energy / torque required to puncture tissue.

[0053] In one embodiment, the cutting portion can be formed by reducing or narrowing the distance or width of the longitudinal gap section between adjacent turns in the proximal portion of the cutting helix. During threading of the helix into tissue, rotation translates into longitudinal advancement of the lead tip into the tissue. Because the cutting effect of the reduced or narrowed gap section occurs in a portion of the helix proximal to the moving section of the helix (e.g., the proximal end), helix mobility for tip advancement (longitudinal advancement due to threading) is maintained. The reduced or narrowed gap section of the helix functions as a pair of rotating scissors. This section is exposed to the engaged tissue as a result of the rotational movement of the lead tip during threading of the helix into tissue, locally cutting the tissue.

[0054] FIG. 3A schematically illustrates a cross-section of the lead tip 20 including a cut helix 30 according to one embodiment prior to puncturing the lead tip 20 from the RV to the septum (SEP). The rotational screwing action is indicated by the semicircular arrows around the lead tip 20. Conventionally, the screwing action is performed clockwise to engage and attach to tissue. Additionally, the straight arrows on the cut helix 30 point to the cut or dissected portion of the cut helix, where the gap width between adjacent turns of the helix is ​​reduced, e.g., to zero. The distal portion of the cut helix 30 with the conventional gap width forms the motile section.

[0055] As the helix 30 is screwed further into the tissue, the tissue gripped by the distal portion (movement section) of the cutting helix 30 moves towards the cutting or dissecting section of the cutting helix 30 where the gripped tissue is subjected to high axial pressure between the rigid (substantially non-deformable metal wire sections) as the gap width decreases, effectively resulting in the tissue cutting process.

[0056] 3B shows a schematic cross-sectional view of the lead tip 20 with the cutting helix 30 of FIG. 3A after penetration of the lead tip 20 into the septum. Penetration of the lead tip 20 into the septum is facilitated by an additional / auxiliary circular cut of tissue around the circumference of the cutting helix 30.

[0057] This auxiliary cutting process continues throughout the puncture process until the physician stops the rotation of the lead device with a drive that may be located at the proximal end or, if a stylet is used, at the distal end.

[0058] 4 shows a schematic side view of a more detailed example of the lead tip 20, including the truncated helix 30, with the lead tip housing 22 partially cut away. The lead tip housing 22 can be designed, for example, with a particular conical shape having the dimensions described above, or any other shape suitable for the puncture process. Thus, the lead tip design of FIG. 4 can be used for LBBP-type applications.

[0059] The distal end of the housing 22 can be tapered, if desired, to provide a thin or sharp leading end to function as a complementary axial cutting portion (e.g., scissors). The housing 22 also covers the proximal section of the cutting helix 30 (where a drive device (not shown) can be attached) and limits the total electrical surface of the cutting helix 30 (e.g., to maintain electrical performance). The housing 22 can be made of a plastic material such as polyetheretherketone (PEEK), which has high biocompatibility and an extremely rigid mechanical structure that supports the cutting effect without the risk of localized deformation.

[0060] FIG. 5 shows a schematic cross-sectional view of a lead tip 20 including a cutting helix 30 and a conical insert 40 according to another embodiment.

[0061] The conical insert 40 can be removably or non-removably fixed (e.g., screwed, glued, press-fit, molded, etc.) to the lead tip 30 within the cutting helix 30, can be made of metal or other rigid material, and can support the cutting process by moving tissue within the cutting helix 30 radially toward the cutting portion (rotary scissors).

[0062] The conical insert 40 may be rotationally symmetrical, which facilitates manufacturing.

[0063] 6 shows a schematic cross-sectional view of a lead tip 20 including a cutting helix 30 and a conical thread 42, according to a further embodiment. Similar to the conical insert of FIG. 5, the conical thread 42 can be made of metal or other rigid material. In addition to its tissue guidance function, the conical thread 42 also provides axial movement functionality to support the moving portion of the cutting helix 30.

[0064] The conical thread 42 can be produced by threading the conical insert 40 of FIG. 5 or by machining a locally thin conical thread (fillet) into the conical insert 40 .

[0065] FIG. 7 shows a schematic cross-sectional view of a lead tip 20 including a cutting helix 30 and a single-sided sharp cutting portion according to a further embodiment.

[0066] In the embodiment of FIG. 7, the cross-sectional profile or shape of the cutting turn 32 of the cutting helix 30 at the minimum gap or gapless cut portion (i.e., where the gap between adjacent turns is closed) is modified to provide a sharp edge facing the closed adjacent turn, thereby increasing the sharpness of the scissors-like cut portion and locally improving the cutting effect.

[0067] The sharp shape of the cutting turns 32 may be oriented primarily in the axial direction. This sharp design can be achieved by locally forming a sharp section of the wire and then coiling the wire to obtain the cutting helix 30 with the cutting turns 32.

[0068] FIG. 8 shows a schematic cross-sectional view of a lead tip 20 according to a further embodiment having a cutting helix 30 and a double-sided sharp cutting portion, with adjacent cutting turns 32, 34 having opposing sharp edges.

[0069] Adjacent cutting turns 32, 34 have two opposing sharp profiles facing each other, further increasing the cutting pressure on the tissue during the screwing process.

[0070] FIG. 9 shows a schematic perspective view of a lead device according to a further embodiment in which the cutting function or cutting portion of the cutting helix is ​​realized by a thin wire 60 (or other filament or thin rod) that can be welded between the two proximal windings of the cutting helix, thereby locally incising tissue as the helix is ​​threaded into the tissue.

[0071] Figure 10 shows a schematic perspective view of a lead device according to another embodiment, in which the cutting function or cutting portion of the cutting helix is ​​achieved by an additional cutting blade 70 at the lead tip of the lead device. To better illustrate the shape of the cutting blade 70, the right portion of Figure 10 shows an exploded configuration of the lead device with the helix removed.

[0072] The additional cutting blade 70 is configured to minimize the energy / force required to penetrate the septal tissue by locally incising tissue located within the helix as the cutting helix rotates and moves longitudinally through the tissue, thereby enlarging the tissue opening in the lead body. The elliptical shape of the blade 70 can be configured with sharp side edges in the rotational direction to cut the tissue. However, the shape of the blade 70 can also be provided in other shapes (e.g., triangular, rectangular, etc.). In the configuration of FIG. 10, the blade 70 is protected within the helix.

[0073] Alternatively, other cutting elements of other shapes may be provided around or within the screw helix.

[0074] In all the above embodiments of Figures 3 to 10, a special puncture design (eg, cone shape) of the lead tip 20 with the above dimensions can be applied.

[0075] In summary, a lead device has been described that includes a distal fixation helix for anchoring the lead tip in a patient's tissue. The fixation helix includes a cutting portion (exposed to the tissue) for cutting tissue circumferentially around the fixation helix in addition to puncturing the distal tip of the fixation helix when the fixation helix is ​​screwed into the tissue, thereby supporting longitudinal insertion of the lead tip with the fixation helix into the tissue.

[0076] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered by way of example or illustration only and not by way of limitation. The invention is not limited to the disclosed embodiments. The invention is applicable to various types of lead devices (e.g., bradycardia or tachycardia lead devices having multi-lumen, coaxial, or coradial configurations) and is applicable to applications in the field of cardiac pacing or sensing systems.

[0077] The proposed lead device, including the truncated helix, can be configured to fit or be compatible with IS1, IS4 (low voltage) or DF4 (high voltage) connectors.

[0078] As another option, the cutting helix 30 of Figures 3, 4, 7 and 8 can be combined with an additional cutting wire 60 of Figure 9 and / or an additional blade 70 of Figure 10 at the distal end of the lead device.

[0079] Other variations of the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. The above description details particular embodiments of the present invention. However, no matter how detailed the foregoing appears in the text, it will be understood that the invention can be embodied in various ways and is therefore not limited to the disclosed embodiments. It should be noted that the use of a particular term in describing a particular feature or aspect of the present invention does not mean that the term is to be redefined herein to include the specific characteristics of the feature or aspect of the invention to which it pertains.

Claims

1. A lead device including a lead tip (20), The lead tip (20) includes a distal fixation helix (30) for fixing the lead tip (20) to the patient's tissue, and the fixation helix (30) includes a cutting portion for cutting the tissue in a circumferential direction of the fixation helix (30) in addition to puncturing the tissue with the distal tip of the fixation helix (30) when the fixation helix (30) is screwed into the tissue, thereby supporting longitudinal insertion of the lead tip (20) having the fixation helix (30) into the tissue. Lead device.

2. 2. The lead device of claim 1, wherein the cut portion includes two exposed adjacent turns (32, 34) of the stationary helix (30), with the longitudinally closed intermediate gap between the two adjacent turns.

3. The lead device of claim 2 , wherein the two adjacent turns (32, 34) of the fixation helix (30) are located in a proximal portion of the fixation helix (30).

4. 4. The lead device of claim 2, wherein at least one of the two adjacent turns of the fixation helix includes a cross-sectional shape having a sharp edge toward the opposite adjacent turn.

5. The lead device of any one of claims 2 to 4, further comprising a conical insert (40) secured to a distal end of the lead tip (20) and surrounded by the fixation helix (30).

6. The lead device of any one of claims 2 to 4, further comprising a conical thread (42) secured to a distal end of the lead tip (20) and surrounded by the fixation helix (30).

7. The lead device of claim 1 , wherein the cutting portion includes a blade element (70) disposed within the fixation helix (30).

8. The lead device of claim 1 , wherein the cutting portion includes a cutting wire (60) disposed between adjacent turns of the fixation helix (30).

9. 9. The lead device of claim 1, wherein the lead tip (20) includes a first electrode formed by the fixation helix (30) and an inter-electrode portion between the fixation helix (30) and a proximal anode.

10. 10. The lead device of claim 9, wherein a ratio of a first outer diameter of the fixation helix (30) to a second outer diameter at a distal end of the inter-electrode portion is set between 0.8 and 1, the first outer diameter is set between 1 and 1.8 mm, the length of the lead tip (20) is set between 8 and 15 mm, and the length of the fixation helix (30) is set between 1.5 and 5 mm.

11. 11. The lead device of claim 9 or 10, wherein the inter-electrode portion has a conical shape.

12. The lead device of claim 1 , wherein the body of the lead device has a co-radial structure.

13. 13. The lead device of claim 1, wherein at least a distal end of the housing (22) of the lead tip (20), surrounding the proximal end of the fixation helix (30), is tapered to form a sharp leading edge that functions as a complementary axial cutting portion.

Images