Cutting type spiral part for lead fixation

Abstract

The invention relates to a lead device comprising a lead tip having a distal fixation helix for fixing the lead tip at tissue of a patient, such as heart tissue, in particular ventricular septal tissue, where the fixation helix comprises a cutting portion for cutting the lead tip into the tissue when the fixation helix is screwed into the tissue. In addition to puncturing through the distal tip of the stationary helix (30), the tissue is cut in the circumferential direction of the stationary helix to assist in longitudinal insertion of the lead tip having the stationary helix into the tissue. Therefore, since the tissue is pre-cut in the circumferential direction at and / or around and / or within the fixation helix during the operation of screwing in the tissue, insertion and longitudinal advancement of the lead tip into the tissue can be facilitated and smoothed.

Description

Technical Field

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

[0002] Different electrical activation sequences of cardiac pacemakers can result in different mechanical pump efficiencies in the stimulated heart. Rapid and uniform ventricular contractions are desired to optimize pump efficiency.

[0003] Although traditional pacing sites such as the right ventricular apex (RVA) provide a stable lead position with low displacement, they are not very effective in optimizing left ventricular (LV) contraction, which represents approximately 80% of cardiac mass. Long-term RVA pacing may have deleterious effects on LV function by inducing iatrogenic left bundle branch block (LBBB), which strongly impacts LV hemodynamic performance. This observation has prompted a reevaluation of traditional approaches and the investigation of alternative pacing sites to achieve more physiologic ventricular activation patterns and avoid deleterious effects.

[0004] Left bundle branch pacing (LBBP) has emerged as an alternative method for providing physiologic pacing to achieve left ventricular (LV) electrical synchronization, particularly in patients with infranodal atrioventricular (AV) block and / or left bundle branch block (LBBB). The proximal left bundle branch (LBB) crosses the LV septum and fans out, creating a wider target area for pacing compared with the His bundle. A LBBP technique has been developed using a transseptal approach (ie, pacing the LV from the right ventricle (RV)). LBBP is reported to have a low pacing threshold and large R-wave amplitude, and because it targets the distal conduction system, it theoretically has a lower risk of distal block.

[0005] After the initial position of the left bundle branch pacing LBBP position has been determined to be at the right surface of the ventricular septum, the pacing lead (i.e., the spiral fixation element or electrode at the lead tip) is screwed into the left ventricular LV septum, for example by piercing the tissue with the distal tip of the spiral fixation element (fixation spiral). The depth of implantation of the left bundle branch pacing LBBP lead into the left ventricular LV septum can be determined by at least one of the following: observing changes in the notch in the V1 lead, sheath angiography, fulcrum sign, and impedance monitoring. The pacing lead is slowly advanced to the determined depth (e.g., approximately 6 mm to 8 mm) by applying torque while avoiding any perforation of the ventricular septum. Finally, left bundle branch LBB capture is confirmed based on acceptable pacing parameters. The confirmation method can be based on at least one of the following: a pacing morphology of a right bundle branch block (RBBB) pattern, a recording of a left bundle branch (LBBB) potential, a stimulation peak of a left ventricular activation time (LVAT) that abruptly shortens with increasing output or remains at a minimum and constant at low and high outputs, selective left bundle branch pacing (LBBP) and non-selective left bundle branch pacing (LBBP), and a recording of a retrograde His potential or an antegrade left bundle branch (LBBB) potential during pacing.

[0006] Common features of the implantation or placement procedure include a transvenous approach, transseptal placement of the pacing lead into the subendocardial LV septum of the left ventricle at the LBBB region, and confirmation of LBBB capture.

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

[0008] However, one challenge with puncturing the ventricular septum or other tissues is optimizing the helical advancement properties with respect to the energy / force required for puncture and the lead design, so that well-controlled and safe advancement can be achieved without increasing the complexity of the lead. To this end, it is important to remember that the inner surface of the cavities of the right ventricle (RV) and left ventricle (LV) is "covered" with a thin, strong skin (membrane or lining) called the "endothelium," which is more difficult to puncture than the interior of the ventricular septum. Summary of the Invention

[0009] An object of the present invention is to provide an electrode catheter system that addresses the above-mentioned challenges associated with left bundle branch pacing (LBBP) or other pacing methods and improves the efficiency of the puncture procedure.

[0010] This object is achieved by a fixing element as claimed in claim 1 .

[0011] The proposed lead device includes a lead tip having a distal fixing spiral portion for fixing the lead tip to the patient's tissue (for example, cardiac tissue, especially ventricular septum tissue), wherein the fixing spiral portion includes a cutting portion for, when the fixing spiral portion is screwed into the tissue, in addition to puncturing through the distal tip of the fixing spiral portion, also cutting the tissue along the circumferential (annular) direction of the fixing spiral portion to assist the longitudinal insertion of the lead tip with the fixing spiral portion into the tissue.

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

[0013] According to a first alternative, the cutting portion can include two adjacent turns of the fixation helix with a closed intermediate gap in the longitudinal direction. During the movement of the fixation helix into the tissue, the tissue is strongly compressed between the two adjacent turns with the closed gap, which results in a scissor-like cutting effect along the circumference of the fixation helix. This provides a simple and cost-effective way to achieve 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 in a proximal portion of the fixation helix. Thus, the distal portion of the fixation helix serves to assist in longitudinal advancement of the lead device by a screw-in operation.

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

[0016] According to a fourth option, which may be combined with any of the first to third options, a tapered insert may be fixed at the distal end of the lead tip and surrounded by the fixation helix. During longitudinal advancement, the tapered insert presses tissue within the fixation helix outward toward adjacent cutting turns, thereby increasing the cutting area and facilitating insertion of the lead tip into the tissue.

[0017] According to a fifth option, which can be combined with any of the first to third options, a tapered screw can be fixed at the distal end of the lead tip and surrounded by a fixed helical portion. During longitudinal advancement, the tapered screw presses tissue within the fixed helical portion outward toward adjacent cutting turns, thereby increasing the cutting area and facilitating insertion of the lead tip into tissue. Furthermore, the tapered screw's threads on the screw surface assist in longitudinal advancement.

[0018] According to a sixth option, which can be combined with any of the first to third options, the cutting portion may include a cutting wire (or other thin wire or rod) arranged between adjacent turns of the fixation helix. During the movement of threading the fixation helix into the tissue, as the fixation helix rotates, the cutting wire cuts the tissue circumferentially. This provides a reliable means of achieving an additional cutting effect.

[0019] According to a seventh embodiment, which can be combined with any of the first to third embodiments, the cutting portion may include a blade element disposed within the fixed helical portion. During the movement of the fixed helical portion into the tissue, the internal blade cuts the tissue along the circumference of the fixed helical portion. This provides another reliable means of achieving an additional cutting effect.

[0020] According to an eighth embodiment, which can be combined with any of the first to sixth embodiments, the lead tip may include a first electrode formed by a fixed helical portion and an inter-electrode portion between the fixed helical portion and the proximal anode. Thus, the inter-electrode portion can be designed according to the requirements of the puncture procedure.

[0021] According to a ninth embodiment, which can be combined with the eighth embodiment, a ratio between a first outer diameter of the fixing helical portion and a 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 mm and 1.8 mm, the length of the lead tip is set between 8 mm and 15 mm, and the length of the fixing helical portion is set between 1.5 mm and 5 mm. Thus, the dimensions of the lead tip can be designed to facilitate insertion of the lead tip into tissue during a puncture procedure.

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

[0023] According to an eleventh option which can be combined with any one of the first to tenth options, the main body of the lead device can have a co-radial structure. This structure realizes a smaller and less rigid lead device, which further facilitates insertion of the lead tip having the fixed helical portion into tissue.

[0024] According to a twelfth embodiment, which can be combined with any one of the first to eleventh embodiments, at least the distal end of the housing of the lead tip surrounds the proximal end of the fixed helical portion, and at least the distal end of the housing of the lead tip is tapered to provide a sharp leading end that serves as a complementary axial cutting portion. Thus, the complementary cutting effect further assists the puncture process.

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

[0026] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In the following figures:

[0028] Figure 1 A heart is schematically shown with a lead set placed for ventricular transseptal left bundle branch (LBB) pacing;

[0029] Figure 2 Schematically illustrates a side view of a lead tip with a conventional fixed helix;

[0030] Figure 3A Schematically illustrates a cross-sectional view of a lead tip having a cutting helical portion before the lead tip is penetrated into the interventricular septum SEP according to one embodiment;

[0031] Figure 3B Schematically shows Figure 3A a cross-sectional view of a lead tip having a cut spiral portion after the lead tip is penetrated into the ventricular septum;

[0032] Figure 4 schematically illustrates a side view of a more detailed example of a lead tip having a cut helical portion, wherein a portion of the lead tip housing is cut away;

[0033] Figure 5 schematically illustrates a cross-sectional view of a lead tip having a cutting helical portion and a tapered insert according to another embodiment;

[0034] Figure 6 schematically illustrates a cross-sectional view of a lead tip having a cutting helical portion and a tapered screw according to yet another embodiment;

[0035] Figure 7 schematically illustrates a cross-sectional view of a lead tip having a cutting helical portion and a single-sided sharp cutting portion according to yet another embodiment;

[0036] Figure 8schematically illustrates a cross-sectional view of a lead tip having a cutting helical portion and bilaterally sharp cutting portions according to yet another embodiment;

[0037] Figure 9 Schematically illustrates a perspective view of a lead device having a fixation helix according to yet another embodiment, wherein the fixation helix comprises a cutting wire;

[0038] Figure 10 Schematically depicts a perspective view of a lead device having a fixation helix surrounding an inner cutting blade according to another embodiment. DETAILED DESCRIPTION

[0039] Various embodiments of the present invention will now be described with respect to an improved lead assembly (e.g., an electrode catheter) having a fixed helical portion. Although the present invention is particularly advantageous in the context of transseptal pacing, such as left bundle branch pacing (LBBP), the present invention is not limited thereto and may also be used in conjunction with other pacing types and / or locations for other applications requiring placement of a lead assembly within body tissue.

[0040] It should be noted that throughout this disclosure, only those elements, parts, components, and / or devices that are relevant to the proposed lead device and placement procedure are shown in the accompanying drawings. For the sake of brevity, other elements, parts, components, and / or devices are omitted. In addition, components represented by the same reference numerals or numbers are intended to have the same or at least similar functions, so that the functions of these components will not be described again below.

[0041] Furthermore, throughout this disclosure, "proximal" and "distal" are terms used to denote the distance from the operating end (reference point) of the lead device, where the physician or other user controls the screwing process. The proximal end is closer to the operating end, while the distal end is further away (by a greater distance) from the operating end.

[0042] Figure 1 A schematic diagram illustrates a heart with a lead assembly 200 inserted, wherein a pacing lead tip 20 is placed for ventricular transseptal left bundle branch pacing (LBBP). Thus, the left ventricle (LV) can be paced from the right ventricle (RV) via a ventricular transseptal approach (as a guide for catheter delivery). The placement of the pacing lead tip 20 can be performed based on the above-described procedure. Left bundle branch pacing (LBBP) can be defined as capturing the left bundle branch (LBB) (i.e., the left main bundle or its proximal bundle), typically at low output (e.g., <1.0 V / 0.4 ms) to achieve septal myocardial capture.

[0043] In normal heart function, the heartbeat is initiated by the heart itself. This occurs at the sinoatrial node (SAN), located at the top of the right atrium (RA) and determining the rate at which the heart contracts. Electrical impulses from the SAN are conducted through the muscular walls of the two atria. These impulses cause the atria to contract. The impulses are then transmitted to another node within the heart, the atrioventricular node (AVN). This node is located in the lower part of the right atrium (RA). Once the impulse from the SAN reaches the AVN, it is transmitted to conducting fibers that travel down the central wall of the heart. The impulses are then shunted and travel upward along the left ventricle (LV) and right ventricle (RV), causing them to contract simultaneously (ventricular contraction).

[0044] The vital components of the cardiac conduction system are located within the ventricular septum 24. The bundle of His runs subendocardially along the right side of the ventricular septum 24 for approximately 1 cm before branching into the left and right bundle branches (LBB). The left bundle branch (LBB) continues downward on the right side of the ventricular septum 24, while the left bundle branch (LBB) crosses to the left and divides into anterior and posterior portions.

[0045] Under normal circumstances, impulses from the sinoatrial node (SAN) control the heart rhythm. Abnormalities in sinus rhythm lead to arrhythmias, which are abnormalities in the rate, rhythm, site of origin, and conduction of the heart's electrical impulses. When a disorder occurs in specific intraventricular conduction fibers, the repolarization wave must reach the ventricles via slower muscle-to-muscle conduction. Typical conditions associated with conditions involving different branches of the conduction bundles include left bundle branch block (LBBB) and right bundle branch block (RBBB). An electrocardiogram (ECG) obtained from an inserted lead device can be used to measure and record the heart's electrical activity and therefore provide important information about heart function. The ECG has been used as a standard diagnostic tool for analyzing arrhythmias.

[0046] The following embodiments of the proposed lead device are configured to minimize any adverse effects upon insertion of the lead device through the ventricular septum 24 (e.g., to prevent permanent damage to the artery) by reducing the puncture area and / or introducing a cutting mechanism with an improved fixation helix.

[0047] The body of the lead device can be configured to improve slidability in contact with a guide catheter used to guide the lead device (e.g., through a blood vessel) to a target area. This can be achieved by using, for example, a polyurethane (PU) material with a reduced diameter to enable easier advancement of the lead body through the guide catheter and advancement of the lead tip 20 through the interventricular septum 24.

[0048] Suitable designs for lead sets can have multi-lumen, coaxial, and co-radial configurations, functioning as both tachycardia and bradycardia leads, and can provide a central lumen for stylet passage. A coaxial lead has an inner conductor that extends down the length of the lead to a tip electrode (helix), i.e., the cathode, arranged in a coil configuration that provides a central lumen, for example, to allow a stylet to pass through the central lumen during implantation.

[0049] The co-radial bipolar lead addresses some of the shortcomings of the coaxial lead in terms of bulk and stiffness of its four-layer design by providing a new conductor and insulator technology, in which a single coil extends down the length of the lead (again with a central lumen to allow insertion of a stylet) and consists of two parallel, alternating conductor strands, one 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 insulates each strand from the other despite the strands being wound together. The single two-part coil can be surrounded by a single outer insulating cover.

[0050] Optionally, the multi-lumen or coaxial or co-radial leads include a fixed, non-retractable helical portion to minimize size. However, a retractable helical portion may also be used in conjunction with the described embodiments.

[0051] In addition, the proposed lead system can be configured to provide improved torqueability, i.e., the ability to safely and accurately transmit torque to the helical portion (e.g., full lead body torque), and stylet drive compatibility to simplify operation (e.g., by push-to-drive). In one example, a co-radial lead can be provided with a compatible screw-type stylet (screwdriver stylet).

[0052] Figure 2 A side view of a lead tip 20 having a conventional fixation helix 30 is schematically shown, the conventional fixation helix 30 having an effective length L that is screwed into cardiac tissue simply by piercing the tissue with the distal tip of the fixation helix 30. The lead device can be used to stimulate the left and / or right bundle branches. The lead device can, for example, include an elongated body extending between a proximal end (not shown) configured to be connected to an implantable pulse generator and a distal end located at the fixation helix 30. The elongated body can also include a lumen extending between the proximal and distal ends.

[0053] In at least some of the following embodiments, with respect to the design of the distal end (distal side) of the lead device, the ratio between the outer diameter of the helical portion 30 and the outer diameter of the housing of the lead tip 20 can be greater than 70%, ideally greater than 100%, wherein an isoprofil distality can be provided to avoid the presence of a front stop surface for better insertion.

[0054] Furthermore, the helical portion 30 may be made of a rigid material to avoid deformation of the helical portion during screwing, while a fixed helical portion (ie, locking between the helical portion 30 and the lead body) may simplify handling (ie, no parasitic tools are required for a retractable system).

[0055] Furthermore, the distance between the fixed helix and the proximal second cathode can be adjusted to accommodate individual differences in interventricular septal thickness among patients, thus providing design flexibility for bilateral pacing.

[0056] The distal design of the lead device can also be configured to enable the lead tip 20 to be smoothly and predictably advanced into the ventricular septum until the spiral portion (cathode) 30 reaches the desired position at the left ventricle (LV) chamber, i.e., close to the left bundle branch (LBB), and does not completely penetrate the ventricular septum so that the spiral portion 30 does not protrude into the left ventricle (LV) chamber.

[0057] In addition, the design of the lead assembly can be configured to minimize the energy / torque required to perform transseptal puncture. For example, this can be achieved by providing a dedicated distal tapered lead tip 20 having a tapered shape for the inter-electrode portion (between the proximal helical end and the distal anode end).

[0058] In some cases, at least the proximal portion of fixation helix 30 can be insulated, and at least one turn at the distal end of fixation helix 30 can be non-insulated. One or more turns of fixation helix 30 (e.g., within the lumen of the elongated body) can be covered with a dielectric or other insulating material. Eliminating the proximal portion or turns of fixation helix 30 can minimize impedance interference that may be caused by the spacing between the proximal electrode (not shown) and fixation helix 30.

[0059] The fixed helical portion 30 can be mounted (e.g., welded) on a driver (not shown), which may include a surrounding coil or other non-flat regular or irregular surface structure to ensure that the surrounding material of the lead body adheres well to the driver in the inter-electrode portion (between the proximal helical portion end and the distal anode end), thereby obtaining a simple, rigid and durable structure of the lead tip 20 with a small number of components to improve long-term reliability. The driver can be fixedly supported in the lead body and mechanically and electrically connected to a screw-in stylet adapter that is adapted to be inserted into the coupling end (joining portion) of a separate screw-in stylet having a screwdriver function so that the helical portion can be rotationally driven via the driver. Due to the electrical connection between the fixed helical portion 30 and the screw-in stylet, the electrical signal sensed by the fixed helical portion 30 at the target area can be transmitted to a signal analyzer via the screw-in stylet and used to monitor the correct placement of the fixed helical portion 30 during the screw-in operation without any disconnection, thereby enabling single-step operation.

[0060] For example, the tapered shape of the lead tip 20 can be based on dimensional parameters of an outer diameter Da of the proximal anode, an outer diameter Dl of the distal segment of the lead tip 20, an outer diameter Dh of the fixed helix 30, a length L of the fixed helix 30, and a total length Lt of the lead tip 20, which includes the fixed helix 30 and a tapered portion of the lead body located between the fixed helix 30 and the proximal anode (e.g., surrounding the driver).

[0061] In an example, the rate Dh / Dl can be set between 0.8 and 1, and Dh can be set between 1 mm 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 mm and 15 mm, and L can be set between 2 mm and 5 mm.

[0062] The specific tapered shape proposed with the aforementioned size range ensures that the lead tip with the fixed helical portion 30 can be used to penetrate tissue in the target area in a controlled and smooth manner, thereby providing a tapered profile that minimizes the energy required to perform the penetration.

[0063] In the following embodiments, the structure of the fixed spiral is enhanced by providing an additional cutting function, which is used to cut tissue in the circumferential direction of the spiral when torque is applied to the lead tip, so as to promote the translation (longitudinal movement) of the lead tip and the spiral during the rotational puncture process and make the translation (longitudinal movement) of the lead tip and the spiral smooth. Thus, a cutting spiral is obtained. More specifically, the cutting portion or element of the cutting spiral, or the cutting portion or element at the cutting spiral is configured to locally dissect tissue located within, at or around the cutting spiral during the rotation and longitudinal movement of the cutting spiral into the tissue and / or expand the tissue opening for the lead tip body. Therefore, when the cutting spiral is screwed into the tissue, the rotary drilling or puncture process performed by the tip at the distal end of the cutting spiral is assisted by the additional circumferential cutting process, so that the energy / torque required to perform tissue puncture can be significantly reduced.

[0064] In one embodiment, a cutting portion can be produced by reducing or closing the distance or width of the longitudinal gap segment between adjacent turns at the proximal portion of the cutting spiral. During the process of screwing the spiral into the tissue, the rotation is converted into the longitudinal advancement of the lead tip in the tissue. Since the cutting effect brought about by the reduced or closed gap portion is provided at a part of the spiral (e.g., the proximal end), and this part is closer to the proximal side than the spiral motion segment, the spiral motion for the tip advancement (longitudinal advancement by screwing) is retained. The reduced or closed gap segment of the spiral acts as a pair of rotating scissors. This segment is exposed to the engaged tissue and, during the screwing of the spiral into the tissue, is locally cut due to the rotational motion of the lead tip.

[0065] Figure 3A Schematically shows a cross-sectional view of a lead tip 20 with a cutting helical portion 30 according to one embodiment before the lead tip 20 is penetrated from the right ventricle RV into the interventricular septum (SEP). The rotational screw-in motion is indicated by the semicircular arrows around the lead tip 20. Typically, the screw-in motion is clockwise for engaging and attaching with tissue. In addition, the straight arrow at the cutting helical portion 30 points to the cutting or dissecting portion of the cutting helical portion, where the gap width between adjacent turns of the helical portion is reduced to zero, for example. The distal portion of the cutting helical portion 30 with a conventional gap width forms the motion segment.

[0066] As the spiral portion 30 is further screwed into the tissue, the tissue grasped by the distal portion (movement section) of the cutting spiral portion 30 will move toward the cutting or dissecting section of the cutting spiral portion 30. In the cutting or dissecting section, when the gap width is reduced, the grasped tissue will be subjected to high axial pressure between the rigid (essentially non-deformable wire sections), thereby effectively achieving the tissue cutting process.

[0067] Figure 3B Schematically shows Figure 3A FIG. 2 is a cross-sectional view of a lead tip 20 having a cutting spiral portion 30 after the lead tip 20 is penetrated into the ventricular septum. Due to the additional / auxiliary annular cutting of tissue around the cutting spiral portion 30, penetration of the lead tip 20 into the ventricular septum is facilitated.

[0068] The auxiliary cutting process will continue during the entire puncture process until the doctor stops the rotation of the lead device, which can be performed at the proximal end or, if a stylet is used, at the driver located at the distal end.

[0069] Figure 4 A side view of a more detailed example of a lead tip 20 having a cut spiral portion 30 with a partially cut away lead tip housing 22 is schematically shown. The lead tip housing 22 can be designed to have a specific tapered shape, such as with the dimensions described above, or any other shape suitable for the puncture procedure. Figure 4 The lead tip design can be used for left bundle branch pacing (LBBP) type applications.

[0070] The distal end of the housing 22 is optionally tapered to obtain a thinned or sharpened front end that acts as a complementary axial cutting portion (e.g., scissors). The housing 22 also covers the proximal section of the cutting helical portion 30 (in which the driver (not shown) can be attached) to limit the total electrical surface of the cutting helical portion 30 (e.g., to maintain electrical performance). The housing 22 can be made of a plastic material such as polyetheretherketone (PEEK) due to its high biocompatibility and extremely rigid mechanical structure to assist the cutting effect without any risk of local deformation.

[0071] Figure 5 A cross-sectional view of a lead tip 20 having a cutting helical portion 30 and a tapered insert 40 according to another embodiment is schematically shown.

[0072] The tapered insert 40 is removably or non-removably secured (e.g., screwed, glued, press-fitted, molded, etc.) to the lead tip 30 within the cutting helical portion 30 and may be made of metal or other rigid material to assist in the cutting process by driving tissue within the cutting helical portion 30 radially outward toward the cutting portion (rotating scissors).

[0073] The tapered insert 40 may be rotationally symmetric, which facilitates its manufacture.

[0074] Figure 6 Schematically shows a cross-sectional view of a lead tip 20 having a cutting helical portion 30 and a tapered screw 42 according to yet another embodiment. Figure 5 The tapered insert of the tapered screw 42 can be made of metal or other rigid materials. In addition to the tissue guiding function, the tapered screw 42 also provides an axial motion function, which assists the moving part of the cutting spiral portion 30.

[0075] Available through Figure 5 The tapered screw 42 is manufactured by cutting threads on the tapered insert 40 or by machining a local fine tapered thread (radius) on the tapered insert 40 .

[0076] Figure 7 Schematically shown is a cross-sectional view of a lead tip 20 having a cutting helical portion 30 and a single-sided sharp cutting portion according to yet another embodiment.

[0077] exist Figure 7 In an embodiment, the cross-sectional profile or shape of the cutting turns 32 of the cutting spiral portion 30 at the cutting portion with minimal gap or no gap (i.e., the gap between adjacent turns is closed) is modified to provide a sharp edge facing the closed adjacent turns, thereby increasing the sharpness of the scissor-like cutting portion to locally improve the cutting effect.

[0078] The sharp shape of the cutting turns 32 may be oriented mainly in the axial direction. The sharp design may be achieved by locally forming a sharp section of the wire and subsequently forming the wire into a coiled shape to obtain the cutting helical portion 30 with the cutting turns 32.

[0079] Figure 8 A cross-sectional view of a lead tip 20 having a cutting helical portion 30 and a double-sided sharp cutting portion according to yet another embodiment is schematically shown, wherein adjacent cutting turns 32, 34 have opposing sharp edges.

[0080] With adjacent cutting turns 32, 34, two opposing sharp profiles face each other, further increasing the cutting pressure on the tissue during the screwing process.

[0081] Figure 9 A perspective view of a lead device according to yet another embodiment is schematically shown, wherein the cutting function or cutting portion of the cutting spiral portion is implemented by a filament 60 (or other thin wire or thin rod), which can be welded between two proximal coils of the cutting spiral portion to locally dissect tissue when the spiral portion is screwed into the tissue.

[0082] Figure 10 1 shows a schematic perspective view of a lead device according to yet another embodiment, in which the cutting function or cutting portion of the cutting spiral portion is realized by an additional cutting blade 70 at the lead tip of the lead device. In order to better illustrate the shape of the cutting blade 70, Figure 10 The right side portion shows the disassembled configuration of the lead device with the helical portion removed.

[0083] The additional cutting blade 70 is configured to minimize the energy / force required to perform puncture of the tissue of the ventricular septum by topically dissecting tissue located within the helical portion and thereby enlarging the tissue opening for the lead body during rotational and longitudinal movement of the cutting helical portion into the tissue. The oval shape of the blade 70 can be configured to have (more) sharp sides in the direction of rotation for cutting through tissue. However, any other shape of blade 70 can be provided (e.g., triangular, rectangular, etc.). Figure 10 In the configuration, the blade 70 is protected inside the helical portion.

[0084] Alternatively, other cutting element(s) having other shapes may be provided around or within the helical portion.

[0085] In Figures 3 to Figure 10 In all of the above embodiments, a special puncture design (eg, a tapered shape) of the lead tip 20 having the above dimensions may be applied.

[0086] In summary, a lead device has been described, which includes a lead tip having a distal fixing spiral portion for fixing the lead tip to patient tissue, wherein the fixing spiral portion includes a cutting portion (exposed to the tissue) for cutting the tissue along the circumferential direction of the fixing spiral portion when the fixing spiral portion is screwed into the tissue, in addition to puncturing through the distal tip of the fixing spiral portion, to assist in longitudinal insertion of the lead tip having the fixing spiral portion into the tissue.

[0087] Although the present invention has been described and illustrated in detail in the drawings and the foregoing description, such description and illustration are to be considered illustrative or exemplary rather than restrictive. The present invention is not limited to the disclosed embodiments. The present invention is applicable to various types of lead devices (e.g., bradycardia or tachycardia lead devices having a multi-lumen structure, a coaxial structure, or a co-radial structure) and applications in the field of cardiac pacing or sensing systems.

[0088] The proposed lead device with a cut helical portion may be configured to be suitable for or adapted to an IS1, IS4 (low voltage) or DF4 (high voltage) connector.

[0089] As another option, Figure 3 Figure 4 、 Figure 7 and Figure 8 The cutting spiral portion 30 may be combined with a Figure 9 Additional cutting wire 60 and / or Figure 10 Additional blade 70.

[0090] By studying the drawings, the disclosure and the appended claims, those skilled in the art can understand and implement other variations to the disclosed embodiments when practicing the claimed invention. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. It is indisputable that the fact that certain measures are cited in mutually different dependent claims does not indicate that the combination of these measures cannot be effectively utilized. The foregoing specific embodiments describe some embodiments of the present invention in detail. However, it will be understood that no matter how detailed the foregoing appears in text, the present invention can be practiced in many ways and is therefore not limited to the disclosed embodiments. It should be noted that when describing certain features or aspects of the present invention, the use of a particular term should not be understood as implying that the term is redefined herein to be limited to including any particular characteristics of the feature or aspect of the invention associated with the term.

Claims

1. A lead device comprising a lead tip (20), the lead tip having a distal fixing helical portion (30) for fixing the lead tip (20) to a patient's tissue, wherein: The fixing spiral portion (30) includes a cutting portion for cutting the tissue along the circumferential direction of the fixing spiral portion (30) when the fixing spiral portion (30) is screwed into the tissue, in addition to puncturing through the distal tip of the fixing spiral portion (30), so as to assist the lead tip (20) having the fixing spiral portion (30) to be longitudinally inserted into the tissue.

2. The lead device according to claim 1, wherein: The cutting portion includes two exposed adjacent turns (32, 34) of the fixing helical portion (30), with a closed intermediate gap between the two adjacent turns in the longitudinal direction.

3. The lead device according to claim 2, wherein: Two adjacent turns (32, 34) of the fixation helix (30) are provided in a proximal portion of the fixation helix (30).

4. The lead device according to claim 2 or 3, wherein: The cross-sectional shape of at least one of the two adjacent turns (32, 34) of the fixing helical portion (30) has a sharp edge facing the opposite adjacent turn.

5. The lead device according to any one of claims 2 to 4, further comprising a tapered insert (40) fixed at the distal end of the lead tip (20) and surrounded by the fixing helical portion (30).

6. The lead device according to any one of claims 2 to 4, further comprising a tapered screw (42) fixed at the distal end of the lead tip (20) and surrounded by the fixing helical portion (30).

7. The lead device according to claim 1, wherein: The cutting portion includes a blade element (70) disposed within the fixed helical portion (30).

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

9. A lead assembly according to any one of the preceding claims, wherein: The lead tip (20) includes a first electrode formed by the fixed helical portion (30) and an inter-electrode portion between the fixed helical portion (30) and a proximal anode.

10. The lead device according to claim 9, wherein: A ratio between a first outer diameter of the fixing helical portion (30) and a 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 mm and 1.8 mm, the length of the lead tip (20) is set between 8 mm and 15 mm, and the length of the fixing helical portion (30) is set between 1.5 mm and 5 mm.

11. The lead device according to claim 9 or 10, wherein: The inter-electrode portion has a tapered shape.

12. A lead assembly according to any one of the preceding claims, wherein: The main body of the lead device has a co-radial structure.

13. A lead assembly according to any one of the preceding claims, wherein: At least the distal end of the housing (22) of the lead tip (20) surrounds the proximal end of the fixing helical portion (30), and at least the distal end of the housing of the lead tip is tapered to obtain a sharp front end serving as a complementary axial cutting portion.

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