Multi-electrode lead with directional electrodes

Abstract

The present invention relates to a multi-electrode lead device comprising an inter-electrode portion between a distal first electrode and a proximal second electrode wherein the inter-electrode portion comprises two or more additional surface electrodes ("directional" surface electrodes) having a reduced circumferential width for directional pacing, and arranged in an axial sequence to obtain an elongated right bundle branch pacing region. Thus, there is no need for multiple lead models for different anatomical structures and / or preoperative examinations to measure the ventricular septal wall thickness. Further, the pacing direction of the additional directional surface electrode may be optimized / adjusted by rotating the lead device about its longitudinal axis, thus optimizing / adjusting the pacing efficiency of the additional directional surface electrode.

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) systems, cardiac resynchronization or tachycardia ("fast heartbeat") 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 contractions of the heart's ventricles are required to optimize pump efficiency.

[0003] Conventional pacing sites, such as the right ventricular apex (RVA), provide stable lead positions with low displacement but are not very effective for optimizing left ventricular (LV) contraction, which represents approximately 80% of heart mass. Long-term RVA pacing can have deleterious effects on LV function by inducing iatrogenic left bundle branch block (LBBB), which can strongly impact LV hemodynamic performance. This finding has prompted a reexamination of conventional approaches and the exploration of alternative pacing sites to achieve more physiological ventricular activation patterns and avoid deleterious effects.

[0004] LBBP has emerged as an alternative method for providing physiologic pacing to achieve LV electrical synchronization, particularly in patients with infranodal atrioventricular block and / or LBBB. Compared with the bundle of His, the proximal left bundle branch (LBB) traverses the LV septum and fans out to create a wider target area for pacing. A LBBP technique has been developed that utilizes 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 carries a lower risk of distal block.

[0005] After the initial location of the LBBP position has been determined to be at 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 LV septum, for example, by piercing 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 at least one of the following methods: observing changes in the V1 lead notch, sheath angiography, a pivot 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, LBB capture is confirmed based on acceptable pacing parameters. This confirmation can be based on at least one of the following: pacing morphology in a right bundle branch block (RBBB) pattern, recording of the LBB potential, a left ventricular activation time (LVAT) stimulus peak that abruptly shortens with increasing output or remains minimal and constant at low and high outputs, selective LBBP and non-selective LBBP, and recording of retrograde His potential or anterograde LBB potential during pacing.

[0006] Common features of the implantation or placement procedure include a transvenous approach, transseptal placement of the pacing lead into the LV septal subendocardium in the region of the LBB, and confirmation of LBB capture.

[0007] However, variations in patient anatomy may explain some of the variability in the interventricular thickness of the LV septum, which can vary from approximately 10 mm to approximately 20 mm. In addition to the uncertainty in overall septal thickness, the location of the LBB conducting fibers deep within the septal tissue is also variable between patients, often closer to the left ventricular border of the septum, for example, approximately 1 mm to 5 mm from the left ventricular border of the septum. To ensure successful left ventricular capture at the lowest capture threshold, the distal electrode of the lead may need to be deployed as close to the LBB fibers as possible while avoiding the risk of penetrating the septum and entering the left ventricular cavity.

[0008] Furthermore, in the case of combined LBB and right bundle branch (RBB) pacing, control of both the LBB and RBB is required through accurate positioning of the LV and RV cathodes, respectively. The delivered electrical pulses need to be designed with low energy consumption. Geometrically, this means that at least one segment of the RV cathode needs to be as close as possible to the RBB fibers, and at least one segment of the LV cathode needs to be as close as possible to the LBB fibers. Summary of the Invention

[0009] An object of the present invention is to provide a lead device that is configured to be used in patients or device recipients despite the differences in the anatomical structure of the ventricular septum (in particular the thickness of the ventricular septum) of the patients or device recipients (hereinafter referred to as "various anatomical structures") while ensuring low energy consumption.

[0010] This object is achieved by a lead device according to claim 1 .

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

[0012] In a bipolar lead having a first electrode and a second electrode (e.g., an anode and at least one cathode), one electrical channel conducts the electrical pacing pulse toward the lead tip and distal first electrode (e.g., cathode), and another channel completes the circuit back to the pacemaker via the proximal second electrode (e.g., anode). Myocardial capture requires a minimum local current density (i.e., the ratio between pacing current (electrons) and paced area) at the contact area (exposed area) of the first electrode (cathode). A smaller exposed area results in increased current density and increased resistance, which preserves battery life because the current is reduced.

[0013] Note that the present invention can also be used in conjunction with unipolar leads. In this case, the second electrode (e.g., the anode) can be provided at or correspond 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 having a single connecting electrode or terminal (e.g., an IS1 connector) can be used at the proximal end of the lead device.

[0014] Thus, the additional two or more directional surface electrodes with reduced circumferential width provide a reduced exposed area by achieving increased current density, thereby achieving low energy / battery consumption, and also extending the longitudinal electrode length of the connector to increase the pacing area. From a geometrical perspective, this means that, for example, for various anatomical structures of the interventricular septum, at least one segment of one of the two or more directional surface electrodes can be placed close to the RBB fibers, while at least one segment of the LV electrode is placed close to the LBB fibers. Therefore, multiple lead phantoms for different anatomical structures and / or preoperative examinations are not required to measure the interventricular septal wall thickness. In addition, the limited pacing direction of the directional pacing electrode closest to the LBB fibers can be optimized / adjusted by rotating the lead assembly about its longitudinal axis, thereby optimizing / adjusting the pacing efficiency of the directional pacing electrode.

[0015] The substrate or body of the elongated surface electrode (i.e., the combination of the pacing surface and the insulating surface) can be configured as a single physical component to maintain a lead design with a desired stiffness variation (stiffness gradient) in the region to be inserted into the ventricular septum. The stiffness variation results in a change in the flexion of the lead tip and an increased risk of breakage. Therefore, multiple pacing surfaces can be arranged (e.g., embedded) on the elongated surface electrode, which can all be electrically connected together and connected to a single terminal or electrode of a connector at the proximal end of the lead device. Since the single terminal or electrode can be constructed as a single mechanical element, the single terminal or electrode can be configured to provide a desired amount of continuous stiffness to protect the lead tip. If there were many separate electrodes, this would create a (sudden) stiffness gradient at each separate electrode, which could damage the lead tip during the puncture process, which can be avoided. Furthermore, the total pacing surface of the elongated surface electrode can thereby span a longer axial distance to maintain good electrical performance by at least one of: increasing the probability of having portions of the elongated surface electrode as close as possible to the tissue region to be stimulated (e.g., RBB) for various anatomical structures (e.g., thickness of the interventricular septum), and maintaining a desired reduced cumulative pacing surface (e.g., 2 mm). 2 Up to 8mm 2 ). The pacing surface can be continuous or discontinuous along the axial and / or circumferential length of the elongated surface electrode, and thus, the elongated surface electrode can be composed of one or more separate pacing surface areas that can be electrically connected together.

[0016] According to a first option, the additional surface electrode can be connected to only one (ie, single) pacing input terminal of the proximal lead connector. Thus, a simple and robust structure with a standard connector (eg, an IS4 connector) can be used to connect the additional surface electrode.

[0017] According to a second option which can be combined with the above-mentioned first option, the additional surface electrode can be formed by a single conductive element which is partially covered by an electrical insulator cover.Thereby, the structure and manufacture of the lead device can be simplified and made robust.

[0018] According to a third option, which can be combined with either of the first and second options, the additional surface electrodes may include a first additional surface electrode and a second additional surface electrode, each of the first additional surface electrode and the second additional surface electrode having an angular width that is substantially semicircular and located on opposite regions of the circumference of the inter-electrode portion. This allows for a simple and robust structure with opposite pacing directions.

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

[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 by a fixation helix, whereby the first electrode can be used to screw the lead tip into the tissue of the ventricular septum.

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

[0022] According to a seventh option that can be combined with the fifth option or the sixth option, a ratio between a first outer diameter of the fixation helix and a 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 mm and 1.8 mm, the length of the elongated surface electrode can be set between 7 mm and 11 mm, and the length of the fixation helix can be set between 1.5 mm 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 may have a conical shape. The conical shape reduces resistance when the lead tip enters tissue during screwing.

[0024] According to a ninth option which can be combined with any one of the first to eighth options, the main body of the lead device may have a coradial structure. The coradial structure enables the lead device to be designed to be smaller in size and less rigid.

[0025] According to the tenth option, which can be combined with any one of the first to ninth options, the axial distance between the distal end of the fixed helical portion 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 may be combined with any one of the first to tenth options, the additional surface electrodes may be configured to obtain a 2 mm 2 Up to 8mm 2The cumulative size of the resulting limited active electrode surface is within the range of . Thus, good electrical performance can be achieved while maintaining current consumption and thus extending the lifetime of the device.

[0027] 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.

[0028] 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

[0029] In the following figures:

[0030] Figure 1 A heart is schematically shown with a lead set placed for ventricular transseptal LBB pacing;

[0031] Figure 2 Schematically shows a side view of a lead device according to a first embodiment, the lead device having a first cathode formed by a fixed helical portion and an elongated second cathode arrangement formed by two limited exposed directional surface electrodes;

[0032] Figure 3 schematically illustrates a cross-sectional front view of the elongated second cathode structure of the first embodiment;

[0033] Figure 4 schematically illustrates a side view of a lead assembly according to a second embodiment, the lead assembly having a first cathode formed by a fixed helical portion and an elongated second cathode arrangement formed by three limited exposed directional surface electrodes; and

[0034] Figure 5 A cross-sectional front view of an elongated second cathode structure of a second embodiment is schematically shown. DETAILED DESCRIPTION

[0035] 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 transseptal pacing such as 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.

[0036] It should be noted that throughout this disclosure, only those elements, parts, components, and / or devices that are relevant to the proposed lead assembly and placement procedures 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.

[0037] Furthermore, throughout this disclosure, "proximal" and "distal" are terms used to indicate the distance from the operating end (reference point) of the lead device, where a physician or other user controls the screwing process. Proximal is closer to the operating end, while distal is further away (at a greater distance) from the operating end.

[0038] Figure 1 A heart is schematically shown with a lead assembly 200 inserted, wherein a pacing lead tip 20 for ventricular transseptal LBBP is positioned. 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. LBBP can be defined as capture of the LBB (i.e., the left main bundle or its proximal branches / fibers), typically accompanied by capture of the ventricular septal myocardium under low-output conditions (e.g., <1.0 V / 0.4 ms).

[0039] In normal heart function, the heartbeat is initiated by the heart itself thanks to the sinoatrial node (SAN), located at the top of the right atrium (RA) and determining the rate of heart contraction. The SAN generates electrical impulses that 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 RA. Once the impulse from the SAN reaches the AVN, it is transmitted to conducting fibers that run down the central wall of the heart. The impulses are then shunted and propagated upward along the LV and RV, causing both to contract simultaneously (ventricular contraction).

[0040] Important components of the cardiac conduction system are located within the ventricular septum 24. The bundle of His extends approximately 1 cm below the endocardium along the right side of the ventricular septum 24 before branching into the LBB and RBB. The RBB continues downward on the right side of the ventricular septum 24, while the LBB crosses the left side and divides into anterior and posterior parts.

[0041] Under normal circumstances, the heart rhythm is controlled by stimulation from the SAN. Abnormalities in sinus rhythm result in arrhythmias, which are abnormalities in the rate, rhythm, site of origin, and conduction of the heart's electrical impulses. When a disturbance occurs in the conduction fibers within a particular ventricle, the repolarization wave must travel via slower muscle-to-muscle conduction to reach the ventricles. Typical disturbances associated with conditions involving different conduction bundle branches include LBBB and RBBB. An electrocardiogram (ECG) obtained from an inserted lead device can be used to measure and record the heart's electrical activity, thereby providing important information about heart function. The ECG has been used as a standard diagnostic tool for analyzing arrhythmias.

[0042] In an embodiment, the lead tip of the pacing or tachycardia lead is designed to avoid the risk of ventricular septal perforation. The pacing or tachycardia lead can also be equipped with a soft tip (e.g., made of silicone) to increase the stop surface. That is, when the spiral fixation element or electrode (hereinafter referred to as the "spiral portion") engages with (cardiac) tissue (e.g., screws into the tissue), the tissue is pushed against the soft tip to prevent the spiral portion from rotating and advancing further within the tissue. The length of the spiral portion can be limited to an effective length of, for example, about 2 mm. The lead and / or the spiral portion needs to be designed to optimize the energy / force required for puncture and to enable good control and safe advancement without increasing the complexity of the lead.

[0043] Furthermore, according to embodiments, the body of the lead device can be configured to improve slidability in contact with a guide catheter used to guide the lead device to a target area (e.g., through a blood vessel). This can be achieved by using, for example, a polyurethane (PU) material with a reduced diameter, so that the lead body can be advanced through the guide catheter with limited force and the lead tip 20 can be advanced through the interventricular septum 24.

[0044] Suitable designs of lead devices according to embodiments can have multi-lumen, coaxial and co-radial structures, functioning as both tachycardia and bradycardia leads, and can provide a central lumen for the passage of a stylet. The inner conductor of a coaxial lead extends down the length of the lead to a tip electrode (helical portion), i.e., the cathode, and is arranged in a coil configuration that provides, for example, a central lumen through which a stylet can pass when implanted.

[0045] 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 enable insertion of a stylet) 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 of, for example, ethylene tetrafluoroethylene (ETFE) fluoropolymer insulation that serves to insulate each strand from the other, even though the two strands are wound together. The single bipolar coil can be surrounded by a single outer insulating cover.

[0046] Multi-lumen or coaxial or co-radial leads optionally 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.

[0047] Furthermore, the proposed multi-electrode lead device according to an embodiment can be configured to provide improved torque conductivity (i.e., the ability to safely and accurately transmit torque to the helical portion (e.g., full lead body torque)) and stylet drive compatibility for ease of handling (e.g., by push-to-drive). In an example, a co-radial lead can be provided with a compatible threaded stylet (screwdriver stylet).

[0048] The following embodiments of the proposed multi-electrode lead device are configured to be usable in a variety of different anatomies having different thicknesses of the ventricular septum and / or RBB and / or LBB fiber structures, and are compatible with applicable standards (e.g., International Standard IS4, which can be used for up to four separate wires). This is achieved by providing an additional elongated surface electrode arrangement in the inter-electrode portion between the distal first electrode (e.g., the helical cathode) and the proximal second electrode (e.g., the surface anode), the elongated surface electrode arrangement having two or more surface electrodes (directional surface electrodes) having a reduced circumferential length to provide directional pacing characteristics in a corresponding limited angular segment around the lead tip 20. The reduced circumferential length of the directional surface electrodes results in a reduction in the exposed pacing surface of the elongated second electrode arrangement for increased current density (i.e., a reduced pacing area for pacing current). The increased current density enables a reduction in the amount of power supplied to the additional elongated surface electrode arrangement, thereby reducing energy / battery consumption. More specifically, in addition to the first cathode formed by the spiral portion, the second cathode can be formed by an additional longitudinally elongated electrode arrangement having a reduced exposed surface for increasing current density. Embodiments relate to different 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 coverage angle of the directional surface electrodes.

[0049] The elongated second cathode arrangement with one or more directional surface electrodes enables two more flexible pacing sites or sides for various anatomies (e.g., for simultaneous LBB pacing and RBB pacing). Thus, a multi-electrode lead can be adapted to various ventricular septal wall thicknesses, for example. To achieve an effective pacing threshold, the total exposed conductive surface of the elongated cathode arrangement needs to physically contact the tissue and expose a limited pacing surface.

[0050] The two pacing electrodes (ie, the first cathode and the additional elongated second cathode arrangement) may be electrically independent by using at least one of different timing, different thresholds, different impedances, and the like.

[0051] Figure 2 Schematically shows a side view of a multi-electrode lead device 200 with a lead tip according to a first embodiment, wherein the multi-electrode lead device has a first cathode (C LV ) and a second cathode arrangement (C RV1 , C RV2 ), the surface electrodes 208a and 208b have a limited circumferential width and are arranged in longitudinal (axial) sequence (ie, longitudinally (axially) adjacent positions) to provide an elongated longitudinal pacing area.

[0052] The lead tip of the lead device 200 includes a fixed helical portion 30 having an effective length a, and the fixed helical portion 30 is screwed into the cardiac tissue (ventricular septal tissue) by piercing the tissue with the distal tip of the fixed helical portion 30. The lead device 200 can be used to stimulate the LBB and RBB. The lead device 200 can, for example, include a slender body extending between a proximal end having a connector 220 and a distal end located at the fixed helical portion 30, and the connector 220 is configured to dock with an implantable pulse generator. The slender body can also include a lumen extending between the proximal end and the distal end.

[0053] In at least some of the following embodiments, with respect to the design of the distal end (distal) of the lead device 200, the ratio / ratio between the outer diameter of the helical portion 30 and the outer diameter of the housing of the lead tip can be greater than 70%, ideally greater than 100%, wherein a constant profile distal design can be provided to avoid the presence of a front stop surface, thereby enabling better insertion.

[0054] Furthermore, the helical portion 30 may be made of a rigid material to avoid deformation of the helical portion 30 during screwing, while securing the helical portion 30 (ie, the lock between the helical portion 30 and the lead body) may simplify handling (ie, the retractable system does not require parasitic tools).

[0055] Additionally, design flexibility may be provided by adjusting the distance b between the fixation helical portion 30 and the proximal elongated second cathode arrangement for bilateral pacing, and / or adjusting the longitudinal length c of the elongated second cathode arrangement to accommodate the desired range of ventricular septal thicknesses in different individuals.

[0056] The distal design of the lead device 200 can also be configured to enable the lead tip to smoothly and predictably advance into the ventricular septum until the spiral portion (cathode) 30 reaches the desired position at the LV chamber, i.e., approaching the LBB without completely perforating the ventricular septum so that the spiral portion 30 does not protrude into the LV chamber.

[0057] In addition, the design of the lead assembly 200 can be configured to minimize the energy / torque required to perform septal puncture. This can be achieved by providing a dedicated distal tapered lead tip (not shown) having a conically shaped inter-electrode portion between the proximal end of the helical portion 30 and the distal end of the proximal anode (A) 206, the proximal anode (A) 206 having an axial or longitudinal length e. The distal end of the anode 206 is located a longitudinal distance d from the distal end of the elongated second cathode.

[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 caused by the spacing between the proximal electrode (not shown) and fixation helix 30.

[0059] The fixing helix 30 can be mounted (e.g., welded) on a driver (not shown), which can include a surrounding coil or other non-flat regular or irregular surface structure (not shown) to ensure good adhesion of the surrounding material of the lead body to the driver between the proximal end of the fixing helix 30 and the distal end of the anode 206, thereby obtaining a simple, rigid and durable structure of the lead tip with a small number of components to improve long-term reliability. The driver (not shown) can be fixedly supported in the lead body and mechanically and electrically connected to a matching threaded stylet (not shown) adapter to enable the insertion of a coupling end (engaging portion) of a separate threaded stylet having a screwdriver function, thereby enabling the fixing helix 30 to be rotationally driven via the driver. Due to the electrical connection between the fixing helix 30 and the threaded stylet, the electrical signal sensed by the fixing helix 30 at the target area can be transmitted to a signal analyzer via the threaded stylet and used to monitor the correct positioning of the fixing helix 30 during the screwing operation without any disconnection, thereby achieving a single-step operation.

[0060] The conical shape of the lead tip can be based, for example, on dimensional parameters of an outer diameter Da of the proximal anode 206, an outer diameter Dl of the distal segment of the lead tip, an outer diameter Dh of the fixed helix 30, a length a of the fixed helix 30, and a total length Lt of the lead tip (e.g., e+d+b), wherein the lead tip includes the fixed helix 30 and a conical portion of the lead body located between the fixed helix 30 and the proximal anode 206 (e.g., surrounding the driver).

[0061] In an example, the rate / ratio 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), the length a of the fixing spiral 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.

[0062] The proposed specific tapered shape having the aforementioned size range ensures that the lead tip having 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] exist Figure 2 and subsequently Figure 4In the specific example shown in FIG, the connector 220 at the proximal end of the lead set 200 includes four separate connector electrodes (terminals), namely, three circumferential connector electrodes 202 and one axial connector electrode 204. The connector design corresponds to a standard IS4 connector and is configured to provide connections for up to four wires or conductors of the lead set 200. In the specific example, three of the four connector electrodes are used to connect to the anode 206, the elongated second cathode arrangement 208a, 208b, and the first cathode at the fixed helix 30. The axial connector electrode 204 corresponds to the cathode C connected to the fixed helix 30 (for LV pacing) via the first wire. LV ) of the first connector electrode (CC LV ) 204. The first circumferential connector electrode (CC) in the circumferential connector electrodes 202 RV ) is connected via a second wire to a surface electrode 208a (C) of an elongated second cathode arrangement (for RV pacing) RV1 ) and 208b(C RV2 Finally, the second circumferential connector electrode (CA) in the circumferential connector electrodes 202 is connected to the anode (A) via a third wire.

[0064] Alternatively, an unused fourth of the four connector electrodes can be used to connect to one of the two surface electrodes 208a, 208b of the elongated second cathode arrangement, so that the two surface electrodes 208a, 208b are connected to different connector electrodes and can therefore be driven by different pacing signals to provide enhanced pacing control functionality.

[0065] Anode 206 can be used as anode with a large surface (e.g., 40 mm 2 ) sensing electrode, and can be a structure as a single electrode or two electrodes.

[0066] exist Figure 2 In an embodiment of the present invention, the elongated second cathode arrangement is formed by two separate directional surface electrodes 208a, 208b having different pacing directions, which can be connected to a wire or line via a common single internal (internal) connection, which is connected to the most proximal one of the three circumferential connector electrodes 202 of the connector 220. They can be formed, for example, by a single mechanical element (conductive electrode) having a cylindrical shape, which is partially coated with an insulating covering (e.g., a parylene coating or other electrically insulating coating) to provide two separated exposed electrode surfaces. Alternatively, the single mechanical element can include two conductive surface elements and a connecting portion connecting the two elements, wherein only the connecting portion is covered by the insulating covering. Thereby, a simple and robust design can be achieved.

[0067] Thus, the elongated second cathode arrangement includes a first exposed area (first directional surface electrode 208a) shaped as a ring segment at a proximal portion (e.g., proximal half) of the elongated second cathode arrangement and a second exposed area (second directional surface electrode 208b) shaped as a ring segment at a distal portion (e.g., distal half) of the elongated second cathode arrangement. In an example, the sum of the total exposed area of ​​the two exposed ring segment areas may be 4 mm 2 Up to 8mm 2 .

[0068] Figure 3 A cross-sectional front view of the elongated electrode structure of the first embodiment is shown, wherein a radial cutting plane intersects the second oriented surface electrode 208b.

[0069] from Figure 3 It can be seen that the angular widths of the ring segments of the first directional surface electrode 208a and the second directional surface electrode 208b cover substantially 180° in opposite directions of the lead tip. Figure 3 As shown by the arrow in FIG. Figure 3 The lower surface electrode 208b directs the pacing effect in the upward direction of Figure 3 The two exposed ring segment electrode areas (cathode) 208a and 208b can be connected to the same internal lead to simplify the internal design and provide a robust electrode structure. The reduced exposed area increases the current density during pacing, thereby enabling reduced energy / battery consumption.

[0070] Figure 4 The figure schematically shows a side view of a multi-electrode lead device according to a second embodiment, wherein the multi-electrode lead device has a first cathode (C LV ) and an elongated second cathode arrangement, the first cathode (C LV ) is formed by a fixed helical portion 30, an elongated second cathode arrangement having a longitudinal length c and formed by three separate directional surface electrodes 209a to 209c having different pacing directions, which can be connected via a common single internal connection to a lead or wire connected to the most proximal one of the three circumferential connector electrodes 202 of the connector 220. The first connector electrode (CC LV ) 204 is connected to the fixed helical portion 30 (cathode C for LV pacing) via a first wire LV ). The first circumferential connector electrode (CC) in the circumferential connector electrodes 202 RV ) are connected via a second wire to three directional surface electrodes 209a (C) of an elongated second cathode arrangement (for RV pacing) RV1 )、209b(C RV2) and 208c(C RV3 Finally, the second circumferential connector electrode (CA) in the circumferential connector electrodes 202 is connected to the anode (A) via a third wire.

[0071] Alternatively, an unused fourth of the four connector electrodes can be used to connect to one of the three surface electrodes 209a to 209c of the elongated second cathode arrangement, such that one of the three directional surface electrodes 209a to 209c is connected to a different connector electrode and can therefore be driven by a different pacing signal to provide enhanced pacing control functionality. As another alternative, the proximal connector 220 can include a fifth connector electrode (not shown) that can be used to connect to another of the three surface electrodes 209a to 209c of the elongated second cathode arrangement, such that each of the three directional surface electrodes 209a to 209c is connected to a different connector electrode and can therefore be driven by its own dedicated pacing signal to provide further enhanced pacing control functionality.

[0072] The three directional surface electrodes 209a to 209c can be formed, for example, from 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 three separate exposed electrode surfaces. Alternatively, the single mechanical element can include three conductive surface elements and a connecting portion that each connects two of the three conductive surface elements, wherein only the connecting portion is covered by the insulating coating. This allows for a simple and robust design.

[0073] Thus, the elongated second cathode arrangement includes a first exposed area (first directional surface electrode 209a) shaped as a ring segment at a proximal portion (e.g., proximal third) of the elongated second cathode arrangement, a second exposed area (second directional surface electrode 209b) shaped as a ring segment at a central portion (e.g., central third) of the elongated second cathode arrangement, and a third exposed area (third directional surface electrode 209c) shaped as a ring segment at a distal portion (e.g., distal third) of the elongated second cathode arrangement. In one example, the sum of the total exposed areas of the three exposed ring segment areas may be 4 mm 2 Up to 8mm 2 .

[0074] Note that with Figure 4 Unlike the example of FIG. 2 , the three directional surface electrodes 209 a to 209 c may be arranged at equal or unequal angular distances around the circumference of the lead tip.

[0075] Figure 5A cross-sectional front view of the elongated electrode structure of the first embodiment is shown, wherein a radial cutting plane intersects the third oriented surface electrode 209c.

[0076] from Figure 5 It can be seen that the angular width of each of the ring segments of the first to third directional surface electrodes 209a to 209c covers less than 90° in different directions of the lead tip. Figure 4 and Figure 5 As shown by the arrow in FIG. 1 , the first directional surface electrode 209a is Figure 4 and Figure 5 The second directional surface electrode 209b is located in the upper direction of the Figure 4 and Figure 5 The pacing effect is directed in the sideways direction, and the third directional surface electrode 209c is at Figure 4 and Figure 5 The three exposed ring segment electrode areas (cathode) 209a to 209c can be connected to the same internal lead to simplify the internal design and provide a robust electrode structure. The reduced exposed area increases the current density during pacing, thereby enabling reduced energy / battery consumption.

[0077] like Figure 5 As shown by the dotted shape in FIG, the fourth directional surface electrode can be arranged opposite to the second directional surface electrode 209b to guide the pacing effect to Figure 4 and Figure 5 in the other (opposite) lateral direction of the lead tip, thereby providing an even distribution of directional surface electrodes around the circumference of the lead tip.

[0078] Throughout the above embodiments, the directional surface electrodes 208a, 208b, 209a to 209c can be annular segments having a rectangular shape and can be arranged at substantially equal distances around the circumference of the lead tip. Alternatively, other shapes (ovals, circles, triangles, etc.) can be provided and / or more than four adjacent (sequential) directional surface electrodes can be provided in the axial direction. The electrode patterns of the directional surface electrodes can overlap or not overlap in the axial and / or circumferential directions of the lead tip. Thereby, a continuously or gradually varying current density can be achieved along the axial and / or circumferential directions of the lead tip. Such varying current density can be used to control pacing efficiency during the puncture process through the helical portion.

[0079] Thus, the total exposed area of ​​the elongated second cathode arrangement can be reduced, while all of the directional surface electrodes of the elongated second cathode arrangement can be connected to a single internal lead or wire to simplify the internal design and provide a robust electrode structure. The reduced exposed area increases current density during pacing, thereby enabling reduced energy / battery consumption. In addition, the limited angular coverage of the directional surface electrodes provides a directional pacing effect that can be controlled by rotational movement of the lead tip to enhance pacing efficiency by directing pacing to a desired tissue area.

[0080] As an example applicable to all the above embodiments, the directional surface electrodes may be configured such that the finite size of the active electrode surface remains constant, which is between 2 mm and 1 mm. 2 Up to 8mm 2 within the range between.

[0081] One or more electrode patterns of directional surface electrodes can be produced by selective insulating covering (e.g., a polyparaxylene coating with high insulation and good biocompatibility), which is achieved, for example, by surface mechanical masking of the limited pacing surface to be retained and / or by (numerically controlled) selective laser ablation of the fully coated electrode surface (local removal of the insulating covering) and / or by laser texturing to add surface material.

[0082] In summary, a multi-electrode lead device has been described that includes an inter-electrode portion between a distal first electrode and a proximal second electrode, wherein the inter-electrode portion includes two or more additional surface electrodes having a reduced circumferential width for directional pacing and arranged in an axial sequence to obtain an elongated pacing region (e.g., an RBB pacing region). Thus, multiple lead phantoms for different anatomies and / or preoperative examinations to measure tissue dimensions (e.g., septal wall thickness) are not required. Furthermore, the pacing direction of the directional surface electrodes can be optimized / adjusted by rotating the lead device about its longitudinal axis, thereby optimizing / adjusting the pacing efficiency of the directional surface electrodes.

[0083] Although the present invention has been described and illustrated in detail through the accompanying 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 can be applied to various types of lead devices (e.g., bradycardia or tachycardia lead devices having multi-lumen, coaxial, or co-radial structures) and applications in the field of cardiac pacing or sensing systems.

[0084] The proposed multi-electrode lead device 200 with an elongated electrode arrangement can be configured to be adapted for or adaptable to an IS4 (low voltage) or DF4 (high voltage) connector or other connector types. The multi-electrode lead device can be used in conjunction with a leadless pacemaker that would have an elongated second cathode arrangement that contacts the RV septal tributary and a first cathode (helical portion) that is able to cross the interventricular septum and therefore must reach the LBB and deliver synchronized pacing pulses to both ventricles. Thus, no additional hardware is required.

[0085] Other variations to the disclosed embodiments may be understood and implemented by those skilled in the art in practicing the claimed invention by studying 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" or "an" does not exclude a plurality. The 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 foregoing description details certain embodiments of the invention. However, it will be understood that, no matter how detailed the foregoing appears in the text, the invention may be practiced in many ways and is therefore not limited to the disclosed embodiments. It should be noted that the use of a particular term in describing certain features or aspects of the invention should not be understood as implying that the term is redefined herein to be limited to including any particular characteristic of the features or aspects of the invention with which the term is associated.

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) configured to be inserted into the ventricular septum of the heart by puncture and used for left bundle branch pacing; a proximal second electrode (206); and 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) having a reduced circumferential area for directional pacing and arranged in an axial sequence to obtain an elongated pacing region.

2. The lead device (200) according to 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) according to 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 cover.

4. The lead device (200) according to any one of the preceding claims, wherein The additional surface electrodes (208a, 208b) include a first additional surface electrode (208a) and a second additional surface electrode (208b), both of which have an angular width that is substantially semicircular and are located on opposite areas of the circumference of the inter-electrode portion.

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

6. The lead device (200) according to any one of the preceding claims, wherein The distal first electrode is formed by a fixed helical portion (30).

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

8. The lead device (200) according to claim 6, wherein: A ratio between a first outer diameter of the fixing helical portion (30) and 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 mm and 1.8 mm, the length of the elongated surface electrodes (208a-c; 209; 212) is set between 7 mm and 11 mm, and the length of the fixing helical portion (30) is set between 1.5 mm and 5 mm.

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

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

11. The lead device (200) according to any one of the preceding claims, wherein The axial distance between the distal end of the fixed spiral portion (30) and the distal end of the additional surface electrode (208a, 208b; 209a-209c) is in the range of 7mm to 12mm, the cumulative axial length of the additional surface electrodes (208a, 208b; 209a-209c) is in the range of 7mm to 11mm, and the axial distance between the distal end of the additional surface electrode (208a, 208b; 209a-209c) and the distal end of the proximal second electrode (206) is in the range of 10mm to 20mm.

12. The lead device (200) according to any one of the preceding claims, wherein The additional surface electrodes (208a, 208b; 209a-209c) are configured to obtain 2 Up to 8mm 2 The cumulative size of the resulting finite active electrode surface is within the range of .

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