Multi-electrode leads, including directional electrodes

Abstract

The present invention relates to a multi-electrode lead device that includes an inter-electrode section between a first distal electrode and a second proximal electrode. The inter-electrode section includes two or more additional surface electrodes ("directional" surface electrodes) arranged axially to achieve a narrow circumferential and elongated right bundle branch pacing region for directional pacing. Therefore, multiple lead models are not required to measure septal wall thickness for different anatomical structures and / or pre-operative testing. Furthermore, the pacing direction of the additional directional surface electrodes, and thus pacing efficiency, can be optimized / adjusted by rotating the lead device around its longitudinal axis.

Description

[Technical Field]

[0001] The present invention relates to the field of lead devices (e.g., electrode catheters) for cardiac pacing systems, such as, but not limited to, 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 for delivering 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 fans 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 LBBP location on the right surface of the interventricular 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, the stimulation peak of LVAT which shortens rapidly with increasing output or remains 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 subendocardial layer in the LBB region, and confirmation of LBB capture.

[0007] However, due to the variability of patient anatomy, there may be some variability in the interventricular thickness of the left ventricular (LV) septum, which can vary from approximately 10 mm to approximately 20 mm. In addition to the uncertainty of overall septal thickness, the location of the LBB conduction fibers deep within the septal tissue also varies between patients, typically located near the left ventricular border of the septum, approximately 1–5 mm away. To ensure successful left ventricular capture at the lowest capture threshold, the distal electrode of the lead may need to be positioned as close as possible to the LBB fibers while avoiding the risk of penetrating the septum and entering the left ventricular cavity.

[0008] Furthermore, in the case of combined LBB and RBB pacing, control of both LBB and RBB must be achieved by correctly positioned LV and RV cathodes, respectively. The delivered electrical pulses must be designed to consume low energy. From a geometrical point of view, this means that at least a portion of the RV cathode must be as close as possible to the RBB fibers, and at least a portion of the LV cathode must be as close as possible to the LBB fibers. Summary of the Invention

[0009] The object of the present invention is to provide a lead device that is designed to be usable while ensuring low energy consumption regardless of differences in the septal structure (particularly its thickness) of patients or device recipients (hereinafter referred to as ``various anatomical structures'').

[0010] This object is achieved by a lead device as claimed in claim 1.

[0011] The proposed lead device includes an inter-electrode section between a first distal electrode and a second proximal electrode, which includes two or more additional surface electrodes ("directional" surface electrodes) arranged axially to reduce the circumferential area (or width) for directional pacing and to obtain an elongated (right bundle branch) pacing area.

[0012] In a bipolar lead containing a first and second electrode (e.g., an anode and at least one cathode), one electrical channel conducts electrical pacing pulses toward the lead tip and the distal first electrode (e.g., the cathode), while the other channel completes the circuit back to the pacemaker via the proximal second electrode (e.g., the anode). Myocardial capture requires that the local current density (i.e., the ratio of pacing current (electrons) to pacing area) be minimized at the contact area (exposed area) of the first electrode (cathode). A smaller exposed area increases current density and also increases resistance, thereby reducing current and extending battery life.

[0013] It should be noted that the present invention can also be used in conjunction with a unipolar lead, in which case the second electrode (e.g., the anode) is located on or corresponds to the housing of a pacing device (e.g., an implantable pacemaker), and the inter-electrode portion can extend from the first electrode to the pacing device. In this case, a connector (e.g., an IS1 connector) including a single connecting electrode or terminal can be used at the proximal end of the lead device.

[0014] Thus, two or more additional directional surface electrodes with reduced circumferential widths reduce energy / battery consumption by reducing the exposed area and increasing current density, while also elongating the joint longitudinal electrode length to expand the pacing area. From a geometric perspective, this means, for example, that in various anatomical structures of the septum, at least a portion of one of the two or more directional surface electrodes can be positioned near the RBB fibers, while at the same time, at least a portion of the LV electrode can be positioned near the LBB fibers. Therefore, multiple lead models for different anatomical structures and / or preoperative testing to measure septal wall thickness are not required. Furthermore, the pacing direction of the directional pacing electrode closest to the LBB fibers, and thus pacing efficiency, can be optimized / adjusted by rotating the lead device around its longitudinal axis.

[0015] The substrate or body of the elongated surface electrode (i.e., the combination of the pacing surface and insulating surface) can be constructed as a single physical component, thereby maintaining a lead design with a desired stiffness gradient in the region that is inserted into the septum. Stiffness gradients can lead to changes in the bending of the lead tip, increasing the risk of breakage. Thus, multiple pacing surfaces can be disposed (e.g., implanted) on the elongated surface electrode, all electrically connected to each other and to a single terminal or electrode on a connector at the proximal end of the lead device. Because the pacing surface can be constructed as a single mechanical element, it can be configured to continuously provide the desired stiffness to protect the lead tip. This avoids the (sharp) stiffness gradients that would occur in the presence of multiple individual electrodes, which could potentially damage the lead tip during the puncture process. This also allows the total pacing surface of the elongated surface electrode to be spread over a longer axial distance, increasing the likelihood that a portion of the elongated surface electrode will be as close as possible to the tissue region to be stimulated (e.g., RBB) in various anatomical structures (e.g., septal thickness) and achieving the desired cumulative reduced pacing surface (e.g., 2-8 mm). 2 ) and / or maintaining good electrical performance. The pacing surface may be continuous or discontinuous along the axial and / or circumferential length of the elongate surface electrode, and thus may be composed of one or more separate pacing surface regions that may be electrically connected to one another.

[0016] According to the first option, the additional surface electrodes may be connected to only one (i.e., a single) pacing input terminal of the proximal lead connector, allowing for connection to the additional surface electrodes using a simple and robust structure including a standard connector (e.g., an IS4 connector).

[0017] According to a second option, which can be combined with the first option, the additional surface electrode can be formed by a single conductive element partially covered with an electrically insulating coating, which can simplify and robust the construction and manufacture of the lead device.

[0018] According to a third option that can be combined with any one of the first and second options, the additional surface electrodes can include a first additional surface electrode and a second additional surface electrode that have an angular width of substantially a semicircle and are located in opposite circumferential regions of the inter-electrode portion, thereby achieving a simple and robust structure with opposite pacing directions.

[0019] According to a fourth option, which can be combined with either one of the first and second options, the additional surface electrodes can include three or four additional surface electrodes with an angular width of less than one-quarter of a circle, thereby enabling three or four pacing directions and increasing the flexibility and efficiency of the pacing effect while keeping energy / battery consumption low.

[0020] According to a fifth option, which can be combined with any one of the first to fourth options, the distal first electrode can be formed with a fixation helix, which allows the first electrode to be used to screw the lead tip into the tissue of the septum.

[0021] According to a sixth option, which can be combined with any one of the first to fifth options, the second proximal electrode can be an anode, allowing all electrodes to be located at the lead tip and easily connected to a proximal connector (e.g., a standard IS4 connector).

[0022] According to a seventh option, which can be combined with the fifth or sixth options, 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 can be set between 0.8 and 1, the first outer diameter can be set between 1 and 1.8 mm, the length of the elongated surface electrode can be set between 7 and 11 mm, and the length of the fixation helix can be set between 1.5 and 5 mm. These dimensions facilitate the process of screwing the lead tip into tissue.

[0023] According to an eighth option, which can be combined with any one of the first to seventh options, the inter-electrode portion can have a conical shape, which reduces resistance when the lead tip enters tissue during the screwing process.

[0024] According to a ninth option, which can be combined with any one of the first to eighth options, the body of the lead device can have a co-radial structure, which allows for a less bulky and less stiff lead design.

[0025] According to a tenth option, which can be combined with any one of the first to ninth options, the axial distance between the distal end of the fixation helix and the distal end of the additional surface electrode can be in the range of 7 mm to 12 mm, the cumulative axial length of the additional surface electrode can be in the range of 7 mm to 11 mm, and the axial distance between the distal end of the additional surface electrode and the distal end of the proximal second electrode can be in the range of 10 mm to 20 mm.

[0026] According to an eleventh option, which can be combined with any one of the first to tenth options, the additional surface electrodes are configured such that the resulting cumulative size of the limited active electrode surface is 2 mm 2 ~8mm 2 This allows for good electrical performance while maintaining current consumption and thereby extending the device life.

[0027] 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.

[0028] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. [Brief explanation of the drawings]

[0029] [Figure 1]1 shows a schematic representation of a heart with a lead device placed for ventricular septal trans-LBB pacing. [Figure 2] Schematically shows a side view of a lead device according to a first embodiment, including a first cathode formed by a fixed helix and a second elongated cathode array formed by two directional surface electrodes with limited exposure. [Figure 3] 2 shows a schematic cross-sectional front view of the elongated second cathode structure of the first embodiment; [Figure 4] Schematically shows a side view of a lead device according to a second embodiment, including a first cathode formed by a fixed helix and a second elongated cathode array formed by three directional surface electrodes with limited exposure. [Figure 5] 10A and 10B show schematic cross-sectional front views of elongated second cathode structures of a second embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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. This allows for pacing of the RV from the LV via a ventricular septal approach, as a guide for catheter delivery. 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 bundles / fibers), typically capturing the septal myocardium with low power (e.g., <1.0 V / 0.4 ms).

[0034] In normal cardiac function, the heartbeat is initiated within the heart by the sinoatrial node (SAN), located at the top of the right atrium (RA), which determines the heart's contraction rate. 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).

[0035] Important elements of the cardiac conduction system reside within the septum 24. The bundle of His courses through the subendocardium for approximately 1 cm along the right side of the septum 24, where it bifurcates into the LBB and RBB. The RBB continues along the right side of the septum 24, and the LBB crosses to the left side, where it bifurcates anteriorly and posteriorly.

[0036] 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.

[0037] In embodiments, the lead tip of a pacing or tachycardia lead is designed to avoid the risk of septal perforation. These lead tips may also be equipped with a soft tip (e.g., made of silicone) to increase the stopping surface. That is, when the helical fixation element or electrode (hereinafter referred to as the "helix") engages (e.g., threads) with (cardiac) tissue, the tissue presses against the soft tip, preventing the helix from rotating and further advancing within the tissue. The length of the helix may be limited to an effective length, e.g., about 2 mm. The lead and / or helix should be designed to optimize the energy / force required for penetration and allow for a well-controlled and safe advancement without increasing the complexity of the lead.

[0038] Additionally, according to embodiments, 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.

[0039] Suitable lead device designs according to embodiments, for either tachycardia or bradycardia leads, can have multi-lumen, 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.

[0040] Co-radial bipolar leads address some of the drawbacks of coaxial leads, such as the bulkiness and stiffness of their four-layer design, through new conductor and 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.

[0041] 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.

[0042] Additionally, the proposed multi-electrode lead device according to embodiments can be configured to provide improved torque transmission, i.e., the ability to safely and accurately transmit torque to the helix (e.g., torque across the entire 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).

[0043] The following embodiments of the proposed multi-electrode lead device are designed to be usable in multiple, varied anatomies with different septal thicknesses and / or RBB and / or LBB fiber structures and to comply with applicable standards (e.g., International Standard IS4, which allows for up to four independent electrical leads). This is achieved by providing two or more additional elongated surface electrode arrangements with reduced circumferential lengths (directional surface electrodes) between a distal first electrode (e.g., a spiral cathode) and a proximal second electrode (e.g., a surface anode) to provide directional pacing characteristics in a corresponding limited angular region around the lead tip 20. The reduced circumferential length of the directional surface electrodes reduces the exposed pacing surface of the elongated second electrode arrangement, increasing current density (i.e., reducing the pacing area of ​​the pacing current). The increased current density reduces the amount of power delivered to the additional elongated surface electrode arrangements, thereby reducing energy / battery consumption. More specifically, in addition to the first cathode formed by the helix, a second cathode can be formed by an additional longitudinally elongated electrode arrangement with a reduced exposed surface area, allowing for increased current density.Embodiments relate to various options for designing the directional surface electrodes of the additional elongated electrode arrangement, for example, by varying at least one of the number, size, and angular coverage of the directional surface electrodes.

[0044] An elongated secondary cathode arrangement containing one or more directional surface electrodes allows for more flexible two-sided pacing (e.g., for simultaneous pacing of the LBB and RBB) for various anatomical structures. This allows the multi-electrode lead to accommodate various septal wall thicknesses, for example. To reach effective pacing thresholds, the entire exposed conductive surface of the elongated cathode arrangement must be in physical contact with tissue, exposing a limited pacing surface.

[0045] The two pacing electrodes (i.e., the first cathode and the additional elongated second cathode array) can be electrically independent by using at least one of different timing, different thresholds, and different impedances, etc.

[0046] FIG. 2 shows a schematic side view of a multi-electrode lead device 200 including a lead tip according to a first embodiment, including a first cathode (C L y) is formed by a fixed helix 30 and a second cathode array (C R y1, C R y2) has a limited circumferential width and is formed by two separate surface electrodes 208a and 208b arranged in longitudinal (axial) order (i.e., adjacent longitudinal positions), thereby providing an elongated longitudinal pacing region.

[0047] The lead tip of the lead device 200 includes a fixation helix 30 (threaded into cardiac tissue) having an effective length a, which is inserted by puncturing cardiac tissue (septal tissue) with the distal tip of the fixation helix 30. The lead device 200 can be used to stimulate the LBB and RBB. The lead device 200 can include an elongate body extending between a proximal end including a connector 220 configured to connect to, for example, an implantable pulse generator, and a distal end located at the fixation helix 30. The elongate body can also include a lumen extending between the proximal and distal ends.

[0048] In at least some of the following embodiments, with regard to the design of the distal end (distality) of the lead device 200, the ratio between the outer diameter of the helix 30 and the outer diameter of the lead tip housing may be greater than 70%, ideally 100%, and an equal profile distality may be provided to avoid an anterior stop surface for better insertion.

[0049] Additionally, the helix 30 may be made of a rigid material to avoid deformation of the helix 30 during screwing, but a fixed helix 30 (i.e., a lock between the helix 30 and the lead body) can simplify handling (i.e., no parasite tools are required for the retractable system).

[0050] Additionally, design flexibility is provided by adapting the distance b between the fixation helix 30 and the proximal elongated second cathode array for bilateral pacing and / or the longitudinal length c of the elongated second cathode array to the desired range of septal thicknesses for different individuals.

[0051] The distal design of the lead device 200 can be further configured to allow the lead tip to be advanced smoothly and predictably 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).

[0052] Additionally, the design of the lead device 200 can be configured to minimize the energy / torque required to perform septal puncture. This can be accomplished by providing a specialized distal tapered lead tip (not shown) with a cone-shaped interelectrode section having an axial or longitudinal length e between the proximal end of the helix 30 and the distal end of the proximal anode (A) 206. The distal end of the anode 206 is located a longitudinal distance d from the distal end of the elongated second cathode.

[0053] 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.

[0054] The fixation helix 30 can be attached (e.g., welded) to a driver (not shown). The driver may include a surrounding coil or other non-planar, regular or irregular surface structure (not shown), which ensures good adhesion between the driver and the surrounding material of the lead body between the proximal end of the fixation helix 30 and the distal end of the anode 206, resulting in a simple, rigid, and durable lead tip structure with fewer parts and improved long-term reliability. The driver (not shown) is fixedly supported on the lead body and mechanically and electrically connected to a matching threaded stylet adapter (not shown) for insertion of the mating end (engagement portion) of a separate threaded stylet, which can rotate the fixation helix 30 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, allowing for monitoring proper placement of the fixation helix 30 without cutting during the threading operation, enabling one-step operation.

[0055] The conical shape of the lead tip can be determined based on dimensional parameters, for example, the outer diameter Da of the proximal anode 206, the outer diameter DI of the distal section of the lead tip, the outer diameter Dh of the fixation helix 30, the length a of the fixation helix 30, and the overall length Lt (e.g., e4-d4-b) of the lead tip, 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 206.

[0056] In an example, the ratio Dh / DI can be set between 0.8 and 1, the ratio 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), the length a of the fixed helix 30 can be set between 2 mm and 5 mm, the difference ba can be set between 5 mm and 7 mm, the longitudinal length c of the elongated second cathode can be set between 7 mm and 11 mm, the distance d can be set between 10 mm and 20 mm, and the longitudinal length e of the anode 206 can be set between 5 mm and 10 mm.

[0057] The 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.

[0058] In the specific example shown in FIG. 2 and subsequently FIG. 4 , the connector 220 at the proximal end of the lead device 200 includes four independent connector electrodes (terminals), including three circumferential connector electrodes 202 and one axial connector electrode 204. This connector design is compatible with a standard IS4 connector and is configured to provide connection for up to four electrical lines or wires of the lead device 200. In the specific example, three of the four connector electrodes are used to connect to the anode 206, the elongated second cathode array 208a, 208b, and the first cathode of the fixation helix 30. The axial connector electrode 204 is connected to the first connector electrode (CC) that connects to the fixation helix 30 (cathode CLV for left ventricular (LV) pacing) via a first line. L The first electrode (CCM) of the circumferential connector electrode 202 corresponds to the surface electrode 208a (CCM) of the elongated second cathode array (for RV pacing) via a second line. R y1) and 208b(C R y2). Finally, the second electrode (CA) of the circumferential connector electrode 202 connects to the anode (A) via a third line.

[0059] Alternatively, an unused fourth of the four connector electrodes can be used to connect to either of two surface electrodes 208a, 208b of the elongated second cathode array, whereby the two surface electrodes 208a, 208b are connected to different connector electrodes and thus driven by different pacing signals, providing enhanced pacing control capabilities.

[0060] The anode 206 has a large surface area (e.g., 40 mm 2 ) can be used as a sensing electrode and can be structured as a single electrode or two electrodes.

[0061] In the embodiment of FIG. 2, the elongated second cathode array is formed by two separate directional surface electrodes 208a, 208b with different pacing directions, which may be connected via a common, single internal connection to a wire or line connecting to the most proximal of the three circumferential connector electrodes 202 of the connector 220. These surface electrodes may be formed, for example, by a single cylindrical mechanical element (conductive electrode) partially coated with an insulating coating (e.g., a parylene coating or other electrically insulating coating) to provide two separate exposed electrode surfaces. Alternatively, the single mechanical element may include two conductive surface elements and a connecting portion connecting the two elements, with only the connecting portion covered by the insulating coating. This may result in a simple and robust design.

[0062] Thus, the elongated second cathode array includes a first exposed area (first directional surface electrode 208a) formed as a ring segment in a proximal portion (e.g., proximal half) of the elongated second cathode array, and a second exposed area (second directional surface electrode 208b) formed as a ring segment in a distal portion (e.g., distal half) of the elongated second cathode array. In one example, the total exposed area of ​​the two exposed ring segment areas is 4 mm 2 ~8mm 2 can have the value

[0063] FIG. 3 shows a cross-sectional front view of the elongated electrode structure of the first embodiment, with a radial cut plane intersecting the second directional surface electrode 208b.

[0064] As can be seen in Figure 3, the angular widths of the ring segments of the first and second directional surface electrodes 208a, 208b cover approximately 180° in opposite directions around the lead tip. As indicated by the arrows in Figure 3, the superior electrode 208a directs the pacing effect in the superior direction in Figure 3, and the inferior electrode 208b directs the pacing effect in the inferior direction in Figure 3. The two exposed ring segment electrode areas (cathodes) 208a and 208b can be connected to the same internal wire, simplifying the internal design and providing a robust electrode structure. The smaller exposed area allows for increased current density during pacing, thereby reducing energy / battery consumption.

[0065] 4 is a schematic side view of a multi-electrode lead device according to a second embodiment. The multi-electrode lead device includes a first cathode (C L y) and an elongated second cathode array formed by three separate directional surface electrodes 209a-209c having a longitudinal length c and different pacing directions, which can be connected via a common single internal connection to a wire or line that connects to the most proximal of the three circumferential connector electrodes 202 of the connector 220. The first connector electrode (CCM 204) connects via a first line to the fixation helix 30 (cathode Ctv for LV pacing). The first electrode (CCM) of the circumferential connector electrode 202 connects via a second line to the three directional surface electrodes 209a (Ctv) of the elongated second cathode array (for RV pacing). R v1), 209b(C R y2), and 208c(C R y3). Finally, the second electrode (CA) of the circumferential connector electrodes 202 connects to the anode (A) via a third line.

[0066] Alternatively, an unused fourth of the four connector electrodes may be used to connect to one of the three surface electrodes 209a-209c of the elongated second cathode array, whereby one of the three directional surface electrodes 209a-209c is connected to a different connector electrode and thus driven by a different pacing signal, providing enhanced pacing control. As another alternative, the proximal connector 220 may include a fifth connector electrode (not shown) that may be used to connect an additional one of the three surface electrodes 209a-209c of the elongated second cathode array, whereby each of the three directional surface electrodes 209a-209c is connected to a different connector electrode and thus driven by a dedicated pacing signal, providing even more enhanced pacing control.

[0067] The three directional surface electrodes 209a-209c can be formed, for example, by a single cylindrical mechanical element (conductive electrode) that is partially coated with an insulating coating (e.g., a parylene coating or other electrically insulating coating) to provide three separate exposed electrode surfaces. Alternatively, the single mechanical element may include three conductive surface elements and connecting portions connecting two of the three conductive surface elements, with only the connecting portions covered with the insulating coating. This allows for a simple and robust design.

[0068] Thus, the elongated second cathode array includes a first exposed area (first directional surface electrode 209a) formed as a ring segment in a proximal portion (e.g., proximal third) of the elongated second cathode array, a second exposed area (second directional surface electrode 209b) formed as a ring segment in a central portion (e.g., central third) of the elongated second cathode array, and a third exposed area (third directional surface electrode 209c) formed as a ring segment in a distal portion (e.g., distal third) of the elongated second cathode array. In one example, the total exposed area of ​​the three exposed ring segment areas is 4 mm 2 ~8mm 2Note that unlike the example of Figure 4, the three directional surface electrodes 209a-209c can be arranged at equal or unequal angles around the circumference of the lead tip.

[0069] FIG. 5 shows a cross-sectional front view of the elongated electrode structure of the first embodiment, with a radial cut plane intersecting the third directional surface electrode 209c.

[0070] As can be seen in Figure 5, the angular width of each ring segment of the first through third directional surface electrodes 209a-209c is less than 90° in different directions of the lead tip. As indicated by the arrows in Figures 4 and 5, the first directional surface electrode 209a directs the pacing effect in the superior direction in Figures 4 and 5, the second directional surface electrode 209b directs the pacing effect in the lateral direction in Figures 4 and 5, and the third directional surface electrode 209c directs the pacing effect in the inferior direction in Figures 4 and 5. The three exposed ring segment electrode areas (cathodes) 209a-209c are connected to the same internal wire, simplifying the internal design and achieving a robust electrode structure. The small exposed area increases current density during pacing, thereby reducing energy / battery consumption.

[0071] As shown by the dotted line in FIG. 5, a fourth directional surface electrode can be placed opposite the second directional surface electrode 209b to direct the pacing effect to the other (opposite) side of FIGS. 4 and 5, thereby evenly distributing the directional surface electrodes around the circumference of the lead tip.

[0072] Throughout the above-described embodiments, the directional surface electrodes 208a, 208b, 209a-209c may be rectangular ring segments and may be substantially equally spaced around the circumference of the lead tip. Alternatively, other shapes (e.g., oval, circular, triangular, etc.) may be provided, and / or four or more adjacent (consecutive) directional surface electrodes may be provided in the axial direction. The electrode patterns of the directional surface electrodes may or may not overlap each other in the axial and / or circumferential directions of the lead tip. This allows for continuous or stepped varying current densities along the axial and / or circumferential directions of the lead tip. This varying current density can be used to control pacing efficiency during the puncture process through the helix.

[0073] This reduces the total exposed area of ​​the elongated second cathode array, and by connecting all directional surface electrodes of the elongated second cathode array to a single internal wire or line, it simplifies the internal design and provides a robust electrode structure. The reduced exposed area increases current density during pacing, reducing energy / battery consumption. Furthermore, the limited angular range of the directional surface electrodes provides a directional pacing effect, which can be controlled by the rotational movement of the lead tip, directing pacing to the desired tissue region, improving pacing efficiency.

[0074] As an example applicable to all of the above embodiments, the directional surface electrode may be 2 to 8 mm 2 The electrode surface area can be configured to maintain a limited active electrode surface size in the range of .

[0075] The electrode pattern of a directional surface electrode can be created by selective insulating coating (e.g., a parylene coating, which provides high insulation and good biocompatibility), achieved, for example, by mechanical masking of the remaining limited pacing surface and / or selective laser ablation (localized removal of insulating coating) of a fully coated electrode surface (using numerical control) and / or laser texturing to add surface material.

[0076] In summary, we have described a multi-electrode lead device that includes an inter-electrode section between a first distal electrode and a second proximal electrode. This inter-electrode section includes two or more additional surface electrodes arranged axially to achieve a narrow, elongated pacing region (e.g., an RBB pacing region) for directional pacing. Therefore, multiple lead models for different anatomies and / or pre-operative testing to measure tissue dimensions (e.g., septal wall thickness) are not required. Furthermore, the pacing direction and, therefore, the pacing efficiency of the directional surface electrodes can be optimized / adjusted by rotating the lead device about its longitudinal axis.

[0077] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are by way of example only and not 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 also applicable to applications in the field of cardiac pacing or sensing systems.

[0078] The proposed multi-electrode lead device 200 with an elongated electrode arrangement can be configured to fit or be adaptable to an IS4 (low voltage) connector, a DF4 (high voltage) connector, or other connector types. The device can be used in combination with a leadless pacemaker that can deliver biventricular synchronous pacing pulses, with the elongated second cathode array contacting the right ventricular (RV) septal branch and the first cathode (helix) passing through the septum to the left ventricular septum, eliminating the need for additional hardware.

[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 invention. However, no matter how detailed the foregoing description 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 invention does not imply that the term 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 (200) for left bundle branch pacing and / or right bundle branch pacing, the lead device (200) comprising: a distal first electrode (30) adapted to be inserted into the septum of the heart by puncture and used for said left bundle branch pacing; a second proximal electrode (206); an inter-electrode portion between the distal first electrode (30) and the proximal second electrode (206); the inter-electrode portion includes two or more additional surface electrodes (208a, 208b; 209a-209c) arranged axially to reduce the circumferential area and obtain an elongated pacing area for directional pacing; A lead device (200).

2. The lead device (200) of claim 1, wherein the additional surface electrodes (208a, 208b; 209a-209c) are connected to only one pacing input terminal of the proximal lead connector (220).

3. The lead device (200) of claim 1 or 2, wherein the additional surface electrodes (208a, 208b; 209a-209c) are formed by a single conductive element partially covered by an insulating coating.

4. 4. The lead device of claim 1, wherein the additional surface electrodes include a first additional surface electrode and a second additional surface electrode, both of which have an angular width of substantially half a circle and are located in opposite circumferential regions of the inter-electrode portion.

5. The lead device (200) of any one of claims 1 to 3, wherein the additional surface electrodes include three or four additional surface electrodes (209a-209c) having an angular width of less than one-quarter of a circle.

6. The lead device (200) of any one of claims 1 to 5, wherein the distal first electrode is formed by a fixation helix (30).

7. The lead device (200) of any one of claims 1 to 6, wherein the proximal second electrode is an anode (206).

8. 7. The lead device of claim 6, wherein a ratio between a first outer diameter of the fixation helix and a second outer diameter of the distal end of the inter-electrode portion is set to 0.8 to 1, the first outer diameter is set to 1 to 1.8 mm, the length of the elongated surface electrode is set to 7 to 11 mm, and the length of the fixation helix is ​​set to 1.5 to 5 mm.

9. The lead device (200) of any one of claims 1 to 8, wherein the inter-electrode portion has a conical shape.

10. The lead device (200) of any one of claims 1 to 9, wherein the body of the lead device (200) has a co-radial structure.

11. 11. The lead device (200) of claim 1, wherein the axial distance between the distal end of the fixation helix (30) and the distal end of the additional surface electrodes (208a, 208b; 209a-209c) is in the range of 7-12 mm, the cumulative axial length of the additional surface electrodes (208a, 208b; 209a-209c) is in the range of 7-11 mm, and the axial distance between the distal end of the additional surface electrodes (208a, 208b; 209a-209c) and the distal end of the proximal second electrode (206) is in the range of 10-20 mm.

12. The additional surface electrodes (208a, 208b; 209a-209c) are arranged such that the resulting cumulative size of the limited active electrode surface is between 2 and 8 mm ２ The lead device (200) of any one of claims 1 to 11, configured to be in the range of

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