Multi-electrode lead with elongated 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 an elongated surface electrode for right bundle pacing, the elongated surface electrode having a reduced exposed area and at least one non-exposed portion, the elongated surface electrode is connected to a single pacing input terminal of the proximal lead connector to achieve increased current density. Elongated surface electrodes with reduced exposed regions reduce energy consumption by achieving increased current density and provide increased right beam branch pacing regions for various anatomical structures.

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 an elongated surface electrode (i.e., having an increased longitudinal length) for right bundle branch pacing, the elongated surface electrode having a reduced exposed area and at least one non-exposed portion to provide an increased right bundle branch pacing area at an increased current density, and wherein the elongated surface electrode is connected to only one (i.e., a single) pacing input terminal of the proximal lead connector.

[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 elongated surface electrode with reduced exposed area is designed to reduce energy consumption by achieving increased current density and provide an increased right bundle branch pacing area. Geometrically, this means that for various septal anatomy, at least one segment of the elongated RV cathode can be placed proximal to the RBB fibers, while at least one segment of the LV cathode can be placed proximal to the LBB fibers. Consequently, multiple lead phantoms for different anatomies and / or preoperative testing are not required to measure septal wall thickness.

[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 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 non-exposed portion may include an electrically insulating cover. The electrically insulating cover serves to reduce the exposed area of ​​the elongated surface electrode, thereby providing an elongated electrode that better conforms to various anatomies while providing increased current density to reduce energy / battery consumption.

[0017] According to a second option, the electrically insulating cover may be arranged in the recess of the elongated surface electrode.Thus, by embedding the electrically insulating cover in the recess, an elongated surface electrode with a reduced exposed area may be manufactured in a reliable and robust manner.

[0018] According to a third option, the elongated surface electrode may comprise a helical electrode pattern wound around the lead body of the lead set. This option provides a straightforward way to reduce the size of the exposed area by simply arranging the helical electrode pattern around the lead body of the lead set in the inter-electrode portion.

[0019] According to a fourth option, the spiral electrode pattern may be arranged around or at least partially embedded in an insulating coating of the lead body.The insulating coating ensures that uncovered portions of the lead body are isolated and thus not exposed.

[0020] According to a fifth option, the non-exposed portion may comprise at least one cut-away portion not covered by the electrically insulating cover. Thus, the elongated surface electrode may be manufactured as a single cylindrical element, and the exposed area may be reduced by simply cutting away the desired portion (e.g., by laser ablation) to increase the current density now provided by the electrode (which thus has a smaller exposed surface area), thereby reducing energy / battery consumption.

[0021] According to a sixth option, a plurality of cutouts may be distributed on the surface of the elongated surface electrode. This measure ensures that the current density is more evenly distributed on the surface of the elongated surface electrode.

[0022] According to a seventh option, which can be combined with any one of the first to sixth 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.

[0023] According to an eighth option, which can be combined with any one of the first to seventh 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).

[0024] According to a ninth option that can be combined with the seventh option or the eighth 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.

[0025] According to a tenth option which can be combined with any one of the first to ninth options, the inter-electrode portion may have a conical shape. The conical shape reduces resistance when the lead tip enters tissue during screwing.

[0026] According to an eleventh option which may be combined with any one of the first to tenth 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.

[0027] According to the twelfth option which can be combined with any one of the first to eleventh options, the axial distance between the distal end of the fixing helical portion and the distal end of the slender surface electrode can be in the range of 7 mm to 12 mm, the axial length of the slender surface electrode can be in the range of 7 mm to 11 mm, and the axial distance between the distal end of the slender surface electrode and the distal end of the proximal second electrode can be in the range of 10 mm to 20 mm.

[0028] According to a thirteenth option which may be combined with any one of the first to twelfth options, the elongated surface electrode may be configured to obtain a 2 mm 2 Up to 8mm 2 The size of the resulting limited active electrode surface is within the range of . Thus, good electrical performance can be achieved while maintaining the current consumption and thus extending the lifetime of the device.

[0029] 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.

[0030] 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

[0031] In the following figures:

[0032] Figure 1 A heart is schematically shown with a lead set placed for ventricular transseptal LBB pacing;

[0033] Figure 2 schematically illustrates a side view of a lead assembly according to a first embodiment having a first cathode formed by a fixed helical portion and a second cathode formed by an elongated electrode structure having an outer covering for limited exposure;

[0034] Figure 3 schematically shows a cross-sectional view of an elongated electrode structure of a first embodiment;

[0035] Figure 4 schematically illustrates a side view of a lead assembly according to a second embodiment having a first cathode formed by a fixed helical portion and a second cathode formed by an elongated helical electrode structure wrapped around the body of the lead assembly to achieve limited exposure;

[0036] Figure 5 schematically shows a cross-sectional view of the elongated spiral electrode structure of the second embodiment; and

[0037] Figure 6 Schematically shown is a side view of a lead assembly according to a third embodiment having a first electrode formed by a fixation helix and a second cathode formed by an elongated electrode structure with cut-away portions for limited / reduced exposure. DETAILED DESCRIPTION

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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).

[0042] 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).

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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).

[0051] The following embodiments of the proposed multi-electrode lead device are configured to be usable for 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 elongated pacing electrode structure having an increased longitudinal width and a reduced exposed pacing surface to reduce battery consumption. More specifically, in addition to the first cathode formed by the helical portion, a second cathode is formed by a longitudinally elongated electrode structure having a reduced exposed surface to increase current density. These embodiments relate to different options for reducing the exposed surface of the elongated electrode structure by, for example, providing a partial covering by an insulating coating, an electrode pattern having a reduced surface, and / or one or more cut-out portions in the conductive electrode surface.

[0052] The elongated second cathode enables two more flexible pacing sites or sides for various anatomical structures (e.g., for simultaneous LBB and RBB pacing). Thus, the multi-electrode lead is adaptable to various ventricular septal wall thicknesses. To achieve an effective pacing threshold, the exposed conductive surface of the elongated cathode needs to physically contact the tissue and expose a limited pacing surface.

[0053] The two pacing electrodes can be electrically independent by using at least one of different timing, different thresholds, different impedances, etc.

[0054] 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 (C RV1 , C RV2 ), the elongated electrode structures 208a-208c have an outer electrically insulating cover 208c to achieve limited exposure.

[0055] 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.

[0056] 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.

[0057] 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).

[0058] Additionally, design flexibility may be provided by adjusting the distance b between the fixation helical portion 30 and the proximal elongated second cathode for bilateral pacing and / or adjusting the longitudinal length c of the elongated second cathode to accommodate the desired range of ventricular septal thicknesses in different individuals.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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).

[0064] 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.

[0065] 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.

[0066] exist Figure 2 and the subsequent Figure 4 and Figure 6 In 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, 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 an elongated second cathode (C for RV pacing) RV1 、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.

[0067] 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.

[0068] exist Figure 2In an embodiment of the present invention, the elongated second cathode is constructed as a single long and (optionally) flexible cathode that is connected via a single internal (internal) connection to a wire or line that is connected to the most proximal one of the three circumferential connector electrodes 202 of the connector 220. Thus, a simple and robust design can be achieved.

[0069] The elongated second cathode includes a first annular exposed area 208a at the proximal end of the elongated second cathode and a second annular exposed area 208b at the distal end of the elongated second cathode. In an example, the sum of the total exposed areas of the two annular exposed areas 208a and 208b may be 4 mm 2 Up to 8mm 2 In order to reduce the overall size of the exposed area of ​​the elongated second cathode, a central portion of the elongated second cathode is coated with an electrically insulating cap 208c.

[0070] Figure 3 A cross-sectional view of an elongated electrode structure of a first embodiment is shown.

[0071] The elongated second cathode is formed from a conductive material into a single, cylindrically shaped mechanical component. The elongated second cathode includes a recessed portion in an insulating central section into which an electrically insulating cap 208c is embedded by depositing an insulating material (e.g., a parylene coating or other insulating coating). This provides two exposed cathode regions (cathodes) 208a and 208b, both connected to the same internal lead, simplifying the internal design and providing a robust electrode structure. The reduced exposed area increases current density during pacing, thereby enabling reduced energy / battery consumption.

[0072] 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 a second cathode (C RV )209, the elongated helical electrode structure has a longitudinal length c and is wrapped around the body of the lead device 200 to achieve limited exposure.

[0073] The elongated second cathode 209 is connected to the most proximal of the three circumferential connector electrodes 202 via a single internal wire or line. The helical electrode structure of the elongated second cathode provides a larger longitudinal length c to better accommodate different ventricular septal anatomy while reducing the exposed surface to reduce energy / battery consumption. The helical electrode structure of the elongated second cathode can be patterned as a single coil or multiple coils connected together.

[0074] Figure 5 A cross-sectional view of an elongated spiral electrode structure of a second embodiment is shown.

[0075] The lead body 211 of the lead assembly 200 can be coated with an insulating coating 210 (e.g., silicone or polyurethane backfill) to reduce the exposed surface (pacing surface), and the spiral pacing coil (or other pattern) 209 is arranged around the insulating coating 210 or partially embedded in the insulating coating 210. Thus, a single long and flexible second cathode is obtained, which can be connected to a wire or line connected to the connector 220 via a single internal connection to achieve a simple and robust design. In an example, the total exposed surface area of ​​the spiral elongated second cathode 209 can be 4 mm 2 Up to 8mm 2 The total length is in the range of 2mm to 10mm.

[0076] Figure 6 A side view of a multi-electrode lead device according to a third embodiment is shown having a first cathode formed by a fixation helix 30 and an elongated second cathode 212 formed by an elongated electrode structure having a cut-away portion 213 for limited / reduced exposure.

[0077] Likewise, the elongated second cathode 212 can be made of a conductive material as a single cylindrical mechanical component. The elongated second cathode includes a cutout portion 213, which can be open (free of conductive material) or filled with an insulating material to reduce the overall size of the exposed surface, thereby increasing current density to reduce energy / battery consumption.

[0078] The cutouts may have an elongated rectangular shape and may be arranged at substantially equal distances around the circumference of the elongated second cathode 212. Alternatively, other shapes (elliptical, circular, slit-shaped, etc.) may be provided and / or more than one cutout may be provided in the axial direction. As another alternative, identical smaller cutouts of different shapes may be distributed over the surface of the elongated second cathode 212. As another alternative, one or more cutouts may be arranged to extend in the circumferential direction of the elongated second cathode 212 to cover a major portion of the circumference of the elongated second cathode 212 or different angular portions thereof.

[0079] Thus, the total exposed area of ​​the elongated second cathode 212 can be reduced while the elongated second cathode 212 is connected to a single internal lead or wire 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.

[0080] As an example applicable to all the above embodiments, the elongated second cathode 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 8mm2 within the range between.

[0081] One or more electrode patterns of the elongated 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 assembly 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 an elongated surface electrode for right bundle branch pacing, the elongated surface electrode having a reduced exposed area and at least one non-exposed portion to achieve increased current density, wherein the elongated surface electrode is connected to a single pacing input terminal of a proximal lead connector. The elongated surface electrode with a reduced exposed area reduces energy consumption by achieving increased current density and provides an increased right bundle branch pacing area for various anatomies.

[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 structure can be configured to be adapted or adaptable to an IS1, IS4 (low voltage), or DF4 (high voltage) connector. The multi-electrode lead device can be used in conjunction with a leadless pacemaker, which will have an elongated second cathode 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. Therefore, 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); wherein the inter-electrode portion comprises an elongated surface electrode (208a-c; 209; 212) for right bundle branch pacing, the elongated surface electrode (208a-c; 209; 212) having a reduced exposed area (208a, 208b) and at least one non-exposed portion (208c; 213); and Wherein, the elongated surface electrodes (208a-c; 209; 212) are connected to only one pacing input terminal of the proximal lead connector (220).

2. The lead device (200) according to claim 1, wherein: The non-exposed portion includes an electrically insulating cover (208c).

3. The lead device (200) according to claim 2, wherein: The electrically insulating cover (208c) is disposed in a recess of the elongated surface electrode (208a-c).

4. The lead device (200) according to claim 1, wherein: The elongated surface electrode comprises a spiral electrode pattern (209) wound around a lead body (211) of the lead device (200).

5. The lead device (200) according to claim 4, wherein: The spiral electrode pattern (209) is arranged around the isolation coating (210) of the lead body (211) or is at least partially embedded in the isolation coating of the lead body.

6. The lead device (200) according to claim 1, wherein: The non-exposed portion includes at least one cut-away portion (213).

7. The lead device (200) according to claim 6, wherein: A plurality of the cutout portions (213) are distributed on the surface of the elongated surface electrode (212).

8. 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).

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

10. The lead device (200) according to claim 8, 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.

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

12. The lead device (200) according to any one of the preceding claims, wherein The main body (211) of the lead device (200) has a co-radial structure.

13. The lead device (200) according to any one of the preceding claims, wherein An axial distance between the distal end of the fixing helical portion (30) and the distal end of the elongated surface electrode (208a-c; 209; 212) is in the range of 7 mm to 12 mm, an axial length of the elongated surface electrode (208a-c; 209; 212) is in the range of 7 mm to 11 mm, and an axial distance between the distal end of the elongated surface electrode (208a-c; 209; 212) and the distal end of the proximal second electrode (206) is in the range of 10 mm to 20 mm.

14. The lead device (200) according to any one of the preceding claims, wherein The elongated surface electrodes (208a-c; 209; 212) are configured to obtain a 2 Up to 8mm 2 The size of the resulting limited active electrode surface is within the range of .

Images