Multi-electrode implantable medical device (IMD)

Abstract

An implantable medical device (IMD) includes a plurality of deep cusps configured to advance into a septum of a patient’s heart in different directions not parallel to the longitudinal axis of the implantable medical device, each of the plurality of deep cusps being configured to deliver cardiac pacing to cardiac tissue distal to the cardiac chamber in which the IMD is implanted, and one or more shallow electrodes that can engage the septum, wherein the one or more shallow electrodes are configured to deliver cardiac pacing to the cardiac chamber in which the IMD is implanted.

Description

Technical Field

[0001] This disclosure relates to medical device systems, such as multi-electrode implantable medical devices (IMDs), which are designed to deliver pacing pulses directly or indirectly to selected cardiac tissue, such as the His bundle of a patient's heart. Background Technology

[0002] In some instances, implantable pacemakers include a pulse generator device with one or more flexible, elongated leads coupled to it. The pulse generator device can be implanted in a subcutaneous pouch remote from the patient's heart, and each of the one or more leads extends from the device to a corresponding electrode, which is coupled to the lead and located at the pacing site in the endocardium or epicardium. Relatively compact implantable medical devices (IMDs), sometimes referred to as wireless pacemakers or intracardiac pacemakers, have also been developed, entirely contained within a relatively compact package configured for implantation, for example, within a chamber of the patient's heart, adjacent to the pacing site. Summary of the Invention

[0003] This disclosure describes fixation mechanisms and electrode configurations for IMDs, such as relatively compact IMDs, and IMDs including elongated implantable medical leads. As used herein, the term "IMD" may refer to the entire IMD itself or a portion thereof. As an example, this disclosure may use the term "IMD" to refer to the entirety of a relatively compact IMD suitable for implantation within a patient's heart cavity. As another example, this disclosure may use the term "IMD" to refer to the distal portion of an elongated lead that can be secured to target tissue (e.g., cardiac tissue) to sense electrical data from pacing pulses or neural stimulation pulses or to deliver electrical data from pacing pulses or neural stimulation pulses to the target tissue. For example, the electrode configurations of this disclosure are suitable for the distal portion of an elongated lead and for a relatively compact IMD suitable for intravascular implantation.

[0004] The electrode configuration disclosed herein provides multiple electrode options for applying pacing therapy to target cardiac tissue outside the heart chambers of the implanted IMD, for example, pacing therapy applied via the His bundle. In contrast, currently available lead designs require clinicians (e.g., implant physicians) to place the lead electrodes as physically as possible close to the His bundle to deliver His pacing therapy.

[0005] Various embodiments of this disclosure relate to lead or compact IMD designs utilizing one or more fixation components as electrodes. By using one or more fixation components as electrodes, the configurations of this disclosure utilize the placement of the fixation components in the atrial septum, interventricular septum, or atrioventricular septum of the heart to control pacing therapy using one or more electrodes physically positioned close to target cardiac tissue, such as the His bundle. The fixation components / electrodes of this disclosure include helical fixation components, serrated components, and one or more of various other examples. When deployed, the fixation components of this disclosure can provide improved tissue fixation, improved penetration to selected depths within tissue (e.g., any of the septa / diaphragms listed above), improved electrode contact with selected tissue, and more precise application of pacing therapy to the His bundle or other target cardiac tissue.

[0006] In one instance, this disclosure relates to an IMD comprising a plurality of deep cusps and one or more shallow electrodes. The deep cusps are configured to advance into a septum of a patient's heart in different directions not parallel to the longitudinal axis of the implantable medical device, wherein each of the plurality of cusps is configured to deliver cardiac pacing to cardiac tissue distal to the cardiac chamber in which the IMD is implanted. One or more shallow electrodes may engage with the septum. Some or all of the one or more shallow electrodes are configured to deliver cardiac pacing to the cardiac chamber in which the IMD is implanted.

[0007] In another instance, this disclosure relates to an IMD comprising a deep electrode and a plurality of shallow cusps. The deep electrode is configured to be advanced into the septum of a patient's heart. The shallow cusps can engage with the septum. A subset of the shallow cusps can be selected to form one or more return electrodes configured in series with a helical lead electrode to deliver pacing therapy to a target site within the septum.

[0008] In another example, a method includes advancing an inner lead that can move within the lumen of an outer lead toward a target site on the patient's heart; engaging the target site with an electrode at the distal end of the inner lead; and advancing the outer lead toward the target site on the patient's heart such that multiple deep serrations at the distal end of the outer lead pierce the septum of the target site on the heart.

[0009] Details of one or more examples are set forth in the accompanying drawings and the following description. Other features, objects, and advantages will be apparent from the description and drawings, as well as from the claims. Attached Figure Description

[0010] Figure 1 This is a conceptual diagram illustrating a portion of an example medical device system configured to implant a relatively compact implantable medical device at a target implantation site.

[0011] Figure 2A This is a conceptual plan view illustrating an example of a relatively compact IMD including an electrode configuration according to the technology of this disclosure.

[0012] Figure 2B Diagram Figure 2A The example dimension of the implementation of IMD shown is illustrated.

[0013] Figure 2C Diagram Figure 2A and 2B The image shows an overhead view of the IMD.

[0014] Figure 2D It is a diagram illustrating the implantation at the target site. Figure 2A-2C The diagram shown is a conceptual representation of an IMD.

[0015] Figures 3A-3F Various examples of IMDs including various electrode configurations are illustrated according to aspects of this disclosure.

[0016] Figures 4A-4F It is a diagram illustrating the process of... Figures 3A-3F The graph shows the electric field change at the His bundle as a function of the angular scan in the computer modeling simulation of the IMD configuration shown.

[0017] Figure 5A and 5B An example IMD that can be configured as a lead-in-lead system according to aspects of this disclosure is illustrated.

[0018] Figure 6 This is a flowchart illustrating an example technique for a lead system for implantation of leads according to aspects of this disclosure. Detailed Implementation

[0019] This disclosure describes an implantable medical device (IMD) with an electrode configuration that allows clinicians to select electrodes to target pacing pulses to selected cardiac tissue, such as the His bundle (hereinafter, "HB") of a patient's heart. The HB is a collection of cardiomyocytes specifically designed for electrical conduction. As part of the heart's electrical conduction system, the HB transmits electrical pulses from the atrioventricular node (located between the atria and ventricles) via its bundle branches. These transmitted pulses indirectly provide electrical conduction to the ventricles, causing depolarization of the ventricular myocardium, which then contracts periodically. For ventricular depolarization to occur (i.e., "capture"), pacing via the HB must have a sufficient electric field strength, for example, exceeding one volt per centimeter or one hundred volts per meter (1 V / cm or 100 V / m).

[0020] Although this article primarily describes the case of targeting the hepatic ventricular (HB), the electrode configurations described herein can be used for any target cardiac tissue that is relatively deeper or relatively distant from the wall tissue of the chamber to which the IMD is implanted. Examples include using an IMD implanted within the atrium (e.g., the right atrium) to target the HB, right bundle branch (RBB), left bundle branch (LBB), or other ventricular tissue. Other examples include using an IMD implanted within the ventricle (e.g., the right ventricle) to target the HB or other cardiac tissue. Targeting portions of the cardiac conduction system, such as the HB and bundle branches, for pacing can be termed conduction system pacing.

[0021] The electrode configurations of this disclosure can be implemented in an IMD comprising a housing coupled to one or more elongated leads, or in a relatively compact IMD small enough to be implanted in a chamber of a patient's heart. In an example of this disclosure implemented in an IMD having a housing coupled to one or more elongated leads, the "housing" may also be referred to as a "canister," and the "elongated leads" may refer to a corresponding lead with an electrode at its distal end. According to several configurations of this disclosure, the distal electrode is positioned within the septum of the patient's heart, for example, relatively close to the hepatic bladder (HB). One or more return electrodes are positioned relative to the septum-embedded electrode, allowing clinicians to use a combination of the distal electrode and one or more return electrodes to direct pacing therapy to the HB. Typically, the distal electrode embedded in the septum at implantation is described as being positioned at the distal end of the IMD or on a lead coupled to the IMD. The electrodes of the IMD can be configured to sense electrical signals from tissue and / or deliver electrical therapy to tissue, such as to the HB of the patient's heart, after IMD implantation.

[0022] Some electrode configuration examples according to this disclosure additionally or alternatively include a plurality of distal electrodes. The distal electrodes may be configured such that their electrically active portions, such as distal ends, are spaced apart from each other in cardiac tissue. Some configurations of this disclosure include exposed electrically active portions at locations along the serrations, not limited to the distal ends of the serrations. In this way, the likelihood of at least one distal electrode being close to or located within target tissue can be increased, and / or multiple target tissues can be sensed or stimulated. In some instances, the distal electrodes can be individually controlled to deliver electrical stimulation, and the IMD can select one or more of the distal electrodes for stimulating target tissues. In some instances, the plurality of distal electrodes include a plurality of serrations extending from the distal end of the IMD or lead in different directions, such as by bending to extend.

[0023] Exemplary fixation components for an IMD, such as those for securing a relatively compact IMD housing or guide distal end to cardiac tissue in which it is implanted, may include a base and multiple fixation tips. In some instances, the fixation tips may function as return electrodes. In some instances, the fixation tips may function as electrodes for pacing and sensing within the implantation chamber, such as atrial pacing and sensing.

[0024] In this disclosure, example systems, devices, and techniques are described with reference to delivering electrodes of an IMD configured as a cardiac pacemaker to a target site (i.e., HB) in a patient's heart. However, it should be understood that the example systems, devices, and techniques of this disclosure are not limited to delivering such IMD electrodes to this specific target site in the heart. For example, the example systems, devices, and techniques described herein can be used to deliver other medical devices, such as sensing devices, neurostimulation devices, medical leads, etc. Furthermore, the example systems, devices, and techniques described herein can be used to deliver any such IMD to other locations within a patient's body. In short, the example systems, devices, and techniques described herein can find useful applications in the delivery of a variety of implantable medical devices for the delivery of treatment or patient sensing to a patient.

[0025] Figure 1 This is a conceptual diagram illustrating a portion of an exemplary medical device system 100 configured to implant a relatively compact implantable medical device 200 (“IMD 200”) at a target implantation site 102. In some instances, such as Figure 1 As illustrated, the target implantation site 102 may comprise an appendage or triangle in the Koch region of the right atrium (RA) of the patient's heart 104. In some instances, the target implantation site 102 may comprise other parts of the heart 100, such as the interventricular septum or other locations within the patient's body. The medical device system 100 may include a delivery tool 106 configured to accommodate and controllably deploy a relatively compact IMD 200. In some instances, a clinician may move the medical device system 100 to the target implantation site 102. For example, with the IMD loaded therein, a clinician may guide the delivery tool 106 upward through the inferior vena cava (IVC) and into the RA of the heart 104. In some instances, other pathways or techniques may be used to guide the delivery tool 106 to other target implantation sites within the patient's body.

[0026] Figure 2A This is a conceptual plan view illustrating an example of a relatively compact IMD 200 including an electrode configuration according to the technology of this disclosure. Figure 2A It was described as illustrating a "plan" because Figure 2AThe diagram illustrates the projection of the IMD 200 onto a horizontal plane. The IMD 200 includes a housing 204 extending from the proximal end to the distal end along a longitudinal axis 206. The housing 204 may be formed of a biocompatible and biostable metal such as titanium. In some instances, the housing 204 may comprise a hermetically sealed enclosure. The housing 204 may include a non-conductive coating and define the return electrode 211 as the uncoated portion of the housing 204. The IMD 200 may include any suitable dimensions. In some instances, the outer diameter of the IMD 200 (e.g., the outer diameter of the housing 204) may be between approximately 10 Frenchimes (Fr) and approximately 30 Fr, such as approximately 20 Fr.

[0027] The IMD 200 may include electronic circuitry, including one or more sensing circuits (e.g., for sensing cardiac signals), therapeutic delivery circuitry (e.g., for generating cardiac pacing pulses), and processing circuitry for controlling the functionality of the IMD 200, and may include deep fangs 208 and shallow fangs 210. As used herein, a "fang" refers to an elongated element extending from the distal end of the housing 204, which may be linear or non-linear. In various embodiments according to this disclosure, the "fang" may have resilient or hyperelastic properties and, in some cases, may be configured to pierce and potentially penetrate or pass through target tissue. In some embodiments, the deep fangs 208 and / or shallow fangs 210 may be coupled to or integrated with a base fixedly attached to or at the distal end of the IMD 200.

[0028] In some instances, one or both of the deep fangs 208, when activated, can serve as distal electrodes. In their respective deformed states, the deep fangs 208 extend a greater distance from the distal end of the housing 204 along the longitudinal axis 206 than the shallow fangs 210 extend a greater distance from the distal end of the housing 204 along the longitudinal axis 206. When deployed in target tissue (e.g., a cardiac septum), in their respective deployed states (e.g., relaxed or deformed), the deep fangs 208 can extend into the target tissue to a greater depth than the shallow fangs 210. In some instances, the deep fangs 208, in their respective deployed states, can pierce or penetrate the entire thickness of the target tissue, possibly from the implantation chamber of the IMD 200 to the cardiac chamber opposite the septum, while the shallow fangs 210, in their respective deployed states, can partially pierce the septum without reaching the chamber opposite the septum from the implantation chamber of the IMD 200.

[0029] Each deep tooth 208 may include a conductor, such as a conductive material having a non-conductive coating, such as polytetrafluoroethylene (PTFE), a portion of which, such as the distal end of the deep tooth, is exposed to the tissue in which the deep tooth 208 is embedded when the IMD 200 is implanted. The electronic circuitry of the IMD 200 may be configured to generate electrical pulses for treatment and deliver these pulses to the tissue adjacent to the deep tooth 208 via an electrode formed from a portion of the deep tooth 208, through the tissue, and back to electrode 211. Each deep tooth 208 may include one or more portions, such as an elastically deformable material pre-designed as one or more curved portions and one or more optional substantially straight portions. The deep teeth 208 and shallow teeth 210 may be formed with a pre-defined deployment shape and may be hyperelastic, for example, made of a nickel-titanium alloy, Nitinol.

[0030] The distal electrode portion of the deep cannula 208 may be spaced apart from the distal end 213 of the housing 204 and may be coupled to sensing and therapeutic delivery circuitry via one or more conductors of a sealed feedthrough assembly (not shown). In some instances, the IMD 200 includes a retrieval structure 212 fixedly attached to or integrally formed therewith the proximal end 214 of the housing 204. The retrieval structure 212 may be configured to temporarily tether the IMD 200 to a delivery catheter or retrieval catheter, such as delivery tool 106. In some instances, the retrieval structure 212 may be configured to connect to a tethering assembly, such as those described in Provisional U.S. Patent Application 62 / 844,674 entitled “TETHER ASSEMBLIES FOR MEDICAL DEVICE DELIVERY SYSTEMS”, the entire contents of which are incorporated herein by reference.

[0031] The shallow cusps 210 can be configured to maintain contact between the deep cusps 208 and tissue at the target implantation site (e.g., target implantation site 102). The shape of each shallow cusp 210 and, in some cases, the deep cusps 208 can be selected to control deployment, tissue fixation, and / or tissue detachment. For example, the shape of the respective cusps may include multiple preset curves on the respective cusp, the curvature (e.g., radius) of each preset curve on the respective cusp, the length of each preset curve, the length of optional straight segments between preset curves, the width of the respective cusp or a segment thereof (e.g., one or more tapered portions), the thickness of the respective cusp, multiple incisions along the length of the respective cusp, the shape of the incisions, or any combination thereof.

[0032] The shallow tooth 210 may include one or more portions. For example, the shallow tooth 210 may include an elastically deformable material pre-defined as one or more curved portions and one or more optional substantially straight portions. In some instances, the shallow tooth 210 defines a strip configured to deform along a plane perpendicular to the longitudinal axis 206 and resist torsion outside that plane. In some instances, the shallow tooth 210 may include two or more curved portions (e.g., joints), as described in Provisional U.S. Patent Application 62 / 825,233 entitled “FIXATION COMPONENTS FOR IMPLANTABLE MEDICAL DEVICES,” the entire contents of which are incorporated herein by reference. For example, one or both shallow teeth 210 may be identical or substantially similar to the tooth described in U.S. Patent Application 62 / 825,233.

[0033] The shallow cusp 210 is configured to have target deflection stiffness and target deployment stiffness. The target deflection stiffness may include a measure of the resistance to forces applied to the IMD 200 in the proximal direction when the deep cusp 208 engages with tissue at the target site 102. In some instances, the target deflection stiffness can be selected such that the shallow cusp 210 can deflect by a predetermined amount, thereby enabling the shallow cusp 210 to be visualized under fluorescence fluoroscopy.

[0034] In some instances, the target deflection stiffness can range from about 0.2 N to about 0.8 N, such as about 0.3 N to about 0.6 N. The deployment stiffness can be included in the IMD 200 from the delivery tool 106 ( Figure 1 The target deployment stiffness is a measure of the force exerted by the shallow cusp 210 as it moves from the deformed configuration to the undeformed configuration when the distal opening 108 of the deep cusp 208 extends to allow the free end of the deep cusp 208 to penetrate the atrial or ventricular myocardium. In some instances, the target deployment stiffness can range from approximately 0.6 N to approximately 1.2 N. Figure 2A Marker 219 is also shown, which in some instances may be a radiopaque marker. Marker 219 is visible through medical imaging such as fluorescence fluoroscopy and allows clinicians to view and adjust the rotational orientation of the IMD 200 to achieve the desired trajectory and / or desired path of the deep canine 208 to the target tissue.

[0035] Figure 2B The diagram shows Figure 2A The example dimension of the implementation of IMD 200 shown is illustrated. For ease of illustration, the deep cusp 210B is not shown in... Figure 2B As shown in the image. Figure 2BAn atrial electrode 215 is shown, which in various instances can be configured to enable atrial pacing and / or sensing. In some instances, shallow serrations 210 may be used additionally or alternatively as an atrial electrode. Deep serrations 208A may extend from the atrial electrode 215 to a length represented by distance 221B, and may extend from the distal end 213 of the housing 204 to a length represented by distance 221A. In various instances, distance 221B may be in the range of two to fifteen millimeters (mm), and distance 221A may be in the range of three to seventeen millimeters.

[0036] Figure 2C A top view or end view of the IMD 200 is shown. Figure 2C In the example shown, IMD 200 includes four shallow teeth 210 equidistantly spaced around the perimeter of IMD 200, but other numbers and spacings of shallow teeth may also be considered. Deep teeth 208A and 208B are spaced apart from each other by a distance 217, which can be expressed in angular units (e.g., degrees). In some examples, the distance 217 can range from 30 to 180 degrees. Figure 2C The number and arrangement of the deep cusps 208 shown are a non-limiting example, and in other examples consistent with this disclosure, the IMD 200 may include a greater number of deep cusps 208 and / or different positions of the deep cusps 208 around the longitudinal axis 206 of the IMD 200. In one non-limiting example, the deep cusps 208 may include four deep cusps evenly distributed circumferentially.

[0037] Figure 2D This is a conceptual diagram illustrating the implantation of an IMD 200 at the target implantation site 102. (Example) Figure 2D As shown in the implantation location, the distal end of each shallow cusp 210 can exit the atrial endocardial surface 18, allowing tissue engagement within the curved portion of each shallow cusp 210. When the shallow cusps 210 engage with the atrial myocardium 19, the deep cusps 208 pierce the tissue at the target implantation site 102 and advance through the atrial myocardium 19 and central fibrous body 16 to position the tip electrode 42 within the ventricular myocardium 14, as shown. Figure 2D As shown. The undeformed structure of the shallow cusp 210 prevents the deep cusp 208 from dislodging from the ventricular myocardium 14. If necessary, the deep cusp 208 can be recaptured using a catheter, such as an IMD 200 comprising the deep cusp 208 and the shallow cusp 210, or it can be recaptured in another manner.

[0038] The length of the deep cusps 208 is chosen such that the tip electrode of each deep cusp 208 reaches a sufficient depth in the tissue layer (e.g., ventricular myocardium) to serve as a stimulation electrode relative to HB or other target tissues, without having to puncture into adjacent cardiac chambers. In various embodiments, the length of the deep cusps 208 may be at least 3 mm but less than 20 mm, less than 15 mm, less than 10 mm, or up to 8 mm.

[0039] In some instances, the corresponding stimulating electrode (tip electrode) of the deep cusp 208 and the distal tip of the shallow cusp 210 can extend approximately equidistantly from the distal end of the housing 204. In this case, as the IMD 200 is advanced away from the distal opening, the distal electrode of the deep cusp 208 and the distal tip of the shallow cusp 210 will simultaneously pierce the tissue at the target implantation site 102. Manual pressure applied proximally to the housing 204 via the advancement tool provides the longitudinal force required to pierce the cardiac tissue at the target implantation site 102.

[0040] In other instances, when the IMD 200 is held in its extended position within the receiver, the distal end of the shallow cusp 210 can extend from the proximal base by a greater length than the deep cusp 208. In this case, the distal end of the shallow cusp 210 first pierces the tissue (before the distal electrode of the deep cusp 208), and as the shallow cusp 210 elastically bends or returns to its bent position, it can pull the IMD 200 toward the atrial endocardial surface 18. This pulling force generated by the shallow cusp 210 contributes a longitudinal force that drives the tip electrode of the deep cusp 208 into the tissue at the target implantation site 102 and pushes the tip electrode toward the pacing site near the HB. In some instances, the pulling force generated by the shallow cusp 210 can drive the tip electrode of the deep cusp 208 into the cardiac tissue to the desired depth for HB pacing, thereby reducing the total amount of implantation force required.

[0041] In other instances, the length of the deep electrode 208 can be greater than the distance the distal ends of the shallow cusps 210 extend when held in the extended position. In this case, the distal electrode of the deep cusp 208 first pierces the atrial endocardium and is partially advanced into the tissue layer before the distal ends of the shallow cusps 210 enter the endocardial tissue. For example, the distal electrode of the deep cusp 208 can be at least partially advanced through the atrial myocardium, and the shallow cusps 210 can be used to increase the longitudinal force driving the distal electrode of the deep cusp 208 through the central fibrous body and into the ventricular myocardium by pulling the IMD 200 toward the atrial endocardial surface when the shallow cusps 210 elastically return to their normally curved position. Distance 227 shows the distance between the distal ends of the deep cusps 208 after implantation. In embodiments where the deep cusps 208 are designed to be spaced apart to disperse during or immediately after implantation, distance 227 can be greater than Figure 2CThe distance 217 is shown. The shallow cusps 210 can be angularly spaced within a range of 40 degrees to 180 degrees.

[0042] Figure 3A Another example IMD 300, including electrode configuration, is illustrated according to aspects of this disclosure. Figure 3A In one example, the IMD 300 includes a helical lead electrode 222, connected in series with a loop return electrode 226, to provide pacing for the HB 224. In a computer-modeled simulation, a peak electric field was observed using the helical lead electrode 222, embedded in the diaphragm and positioned close to the HB 224, with the loop return electrode 226 located in the corresponding chamber of the heart and as close to the diaphragm as possible. In this computer-modeled simulation, the center of the helical lead electrode 222 was located 0.25 inches from the center of the HB 224. A peak therapeutic electric field of 0.0557 V / cm (or 5.57 V / m) was observed at the HB 224 when 1 V was applied to the helical lead electrode 222 and 0 V was applied to the loop return electrode 226.

[0043] Figure 3B Another embodiment of the IMD 400 according to aspects of this disclosure is illustrated. Figure 3B In the embodiment shown, the IMD 400 includes, as Figure 3A The helical lead electrode 222 shown delivers His pacing and a segmented return electrode (also known as a “segmented loop electrode”) in series to the HB 224. This segmented return electrode includes electrode segments 426A, 426B, and 426C (collectively, “electrode segments 426”). Clinicians can configure the helical lead electrode 222 and one or more electrode segments 426 to direct the electric field to the HB 224.

[0044] exist Figure 3B In the example shown, each corresponding electrode segment 426 covers 60 degrees of the circumference of the IMD 400, with a 60-degree gap between each pair of segments 426. In a computer-modeled simulation, the active electrode segments 426 of the segmented return electrode are rotated around the helical center to observe the peak electric field in the HB 224 bundle, where 1V is applied to the helical lead electrode 222 with angular steps of 5 degrees over a 360-degree region. The peak electric field obtained in this computer-modeled simulation is 0.0508V / cm (or 5.08V / m) when the active electrode segment 426 is closest to the HB 224.

[0045] Figure 3C Another embodiment of the IMD 500 according to aspects of this disclosure is illustrated. Figure 3C In the illustrated embodiment, the IMD 500 includes a spiral lead electrode 222, such as Figure 3A and 3BAs shown, it transmits His pacing and tooth return electrode 526 in series to HB 224. Figure 3C The diagram illustrates two toothed electrodes, namely toothed return electrodes 526A and 526B. The IMD 500 also includes a third toothed return electrode, which... Figure 3C Not visible in the view of the IMD 500 shown. In various instances, the IMD 500 may include any number of toothed return electrodes 526 with any spacing between them.

[0046] In the illustrated example, the pointed return electrodes 526 are spaced at equal angles (i.e., spaced 120 degrees apart around the circumference of the distal end of the IMD 500). Figure 3C In the computer-modeled simulation of the IMD 500 configuration shown, all three serrated return electrodes 526 capture the diaphragm and penetrate 0.88 mm into the diaphragm wall, located 250 mils from HB 224. In the computer-modeled simulation, the active serrated return electrodes 526 are oriented 180 degrees to HB 224. When the active serrated return electrodes 526 are closest to HB 224, a peak electric field of 0.5134 V / cm (or 51.34 V / m) is obtained by applying 1 V to the spiral lead electrode 222 and using 5-degree angular steps over a 360-degree region.

[0047] In another computer-modeled simulation, three serrated return electrodes 526 were placed on the diaphragmatic wall of the heart to prevent bundle damage to HB 224 that could occur during diaphragmatic puncture placement. The computer-modeled simulation of this placement showed a significantly reduced electric field strength in HB 224 (compared to diaphragmatic puncture placement). In this simulation, a peak electric field of 0.123 V / cm (or 12.3 V / m) was observed at HB 224 with a 1 V applied by the helical lead electrode 222. These results represent approximately 25% of the electric field strength calculated in the computer-modeled simulation, where the serrated return electrodes 526 were positioned to puncture the diaphragm.

[0048] Figure 3D Another embodiment of the IMD 600 according to aspects of this disclosure is illustrated. Figure 3D In the illustrated embodiment, the IMD 200 includes a spiral lead electrode 222, such as Figures 3A-3C As shown, it delivers His pacing to HB 224 in series with one or more of the total six toothed return electrodes 526. For ease of illustration, in Figure 3D In the middle, only the four pointed return electrodes 526 are marked with reference numbers (526A-526D).

[0049] and Figure 3C Compared to the implementation shown, Figure 3DThe illustrated implementation of the IMD 600 includes double the number of toothed return electrodes 526. In some instances, the toothed return electrodes 526 are grouped into sets of two electrically common toothed return electrodes, forming three total electrode sets connected in series with the helical lead electrode 222. The six toothed return electrodes 526 are equidistantly spaced (from an angular viewpoint), with a 60-degree interval between each pair of adjacent toothed return electrodes 526 along the circumference of the distal end of the IMD 600. Using... Figure 3D With the configuration shown, clinicians can capture a beam of HB 224 anywhere within a half-inch diameter circle around the distal end of the IMD 600. Figure 3D The peak electric field observed in the configuration shown is 0.457 V / cm (or 45.7 V / m). The toothed return electrode 526 can be used as follows... Figure 3C and 3D The diagram shows a convex shape relative to the outer surface of the diaphragm.

[0050] Figure 3E A view of another embodiment of the IMD 700 according to aspects of this disclosure is shown. Figure 3E In the illustrated embodiment, the IMD 200 includes, as shown below: Figures 3A-3D The spiral lead electrode 222 shown, in series with one or more of the three inverted toothed return electrodes 726A-726C (collectively referred to as "toothed return electrodes 726"), delivers His pacing to HB 224. Figure 3E The IMD 700 shown is designed to address situations where the serrations may not be desired to penetrate the septum wall, given the possibility that the serrations could damage HB 224 or one or more of its branches. To prevent such potential His bundle damage in these cases, Figure 3E The design of the IMD 700 shown includes an inverted toothed return electrode 726 that contacts the diaphragm in such a way that the bottom edge of the umbrella may rest on a flat or substantially flat surface.

[0051] When deploying IMD 700 (if according to...) Figure 3E As shown in the design and fabrication, the inverted serrated return electrode 726 can contact the diaphragm or other endocardial tissue without penetrating into the tissue. In performance computer modeling simulations, the inverted serrated return electrode is confined within a circle with a diameter of 600 mils outside the diaphragmatic wall. When 1 V is applied to the helical lead electrode 222, a peak electric field of 2.016 V / cm (or 201.6 V / m) is observed at HB224. For a single inverted serrated return electrode 726, the useful angle treatment coverage is approximately 70 degrees.

[0052] Figure 3F Another embodiment of the IMD 800 according to aspects of this disclosure is illustrated. Figure 3FIn the embodiment shown, the IMD 800 includes, as Figures 3A-3E The spiral lead electrode 222 shown, connected in series with a total of six inverted toothed return electrodes 726, delivers His pacing to HB 224. For ease of illustration, in Figure 3F In the middle, only four inverted toothed return electrodes 726, namely toothed return electrodes 726A-726D, are marked with reference numbers.

[0053] and Figure 3E Compared to the implementation shown, Figure 3F The illustrated implementation of the IMD 800 includes double the number of toothed return electrodes. In some instances, the inverted toothed return electrodes 726 are grouped into sets of two electrically common inverted toothed return electrodes 726, forming three total electrode sets that can be used in combination with the spiral lead electrode 222. Using as... Figure 3F The configuration shown allows clinicians to capture a beam of HB 224 anywhere within a half-inch diameter circle. With Figure 3F The peak electric field observed in the configuration shown is approximately 1.7 V / m (or 170 V / cm). Simulation results from computer modeling indicate that an angular spacing of less than 60 degrees between adjacent inverted toothed return electrodes 726 is beneficial for reducing the null depth (described in further detail below). The toothed return electrodes 726 can be configured as follows: Figure 3C and 3D The diagram shows a concave shape relative to the outer surface of the diaphragm.

[0054] exist Figures 3A-3F In each of these, the spiral electrode 222 represents a deep electrode, while the corresponding return electrode represents a shallow electrode. The deep electrode is configured to extend from the distal end of the corresponding IMD a greater distance than the shallow electrode extends from the distal end of the corresponding IMD. When deployed in a target tissue (e.g., a cardiac septum), the deep electrode can extend into the target tissue to a greater depth than the shallow electrode in its respective deployment state (if applicable). In some instances, the deep electrode can pierce or penetrate the entire thickness of the target tissue, possibly from the implantation chamber of the IMD to the cardiac chamber opposite the septum, while the shallow electrode (in its respective deformed state, if applicable) may partially pierce the septum without reaching the chamber opposite the septum from the implantation chamber of the IMD.

[0055] Figure 4A It is a diagram illustrating the process of... Figure 3B The graph shows the electric field change at HB 224 as a function of angle scan in a computer-modeled simulation of the IMD 400 configuration, where the segmented return electrode includes electrode segment 426. (See above regarding...) Figure 3BAs described, when the active electrode (i.e., the active segment 426 of the segmented return electrode) is closest to HB 224, the peak electric field obtained in the computer modeling simulation is 0.0508 V / cm (or 5.08 V / m).

[0056] Figure 4B It is a diagram in the context of Figure 3C The graph shows the electric field change at HB 224 as a function of angle scan in a computer-modeled simulation of the IMD 500 configuration shown, which has three pointed return electrodes 526. (See above regarding...) Figure 3C As described, when the active tooth return electrode 526 is closest to HB 224, the peak electric field obtained in the computer modeling simulation is 0.5134 V / cm (or 51.34 V / m). Figure 4B The curves show that for each toothed return electrode 526, there is a spatial radial section of approximately 60 degrees around it, which shows a significant improvement in the peak electric field in HB 224.

[0057] Figure 4C This diagram illustrates the situation when the toothed return electrode 526 is placed in non-invasive contact with the diaphragm. Figure 3C The graph shows the electric field change at HB 224 as a function of angle scan in a computer-modeled simulation of the IMD500 configuration shown, which has three pointed return electrodes 526. According to... Figure 3C The alternative placement of the IMD 500, designed and manufactured in this way, shows a significant reduction in the electric field strength in the HB224, where 1V is applied to the spiral lead electrode 224. (See above regarding...) Figure 3C As described, when 1V is applied to the spiral lead electrode 222, with the toothed return electrode making only non-invasive contact with the diaphragm, a peak electric field of 0.123V / cm (or 12.3V / m) is observed at HB 224. These results are approximately 25% of the electric field strength calculated in computer-modeled simulations where the toothed return electrode 526 is positioned to pierce the diaphragm.

[0058] Figure 4D It is a diagram in the context of Figure 3D The graph shows the electric field change at HB 224 as a function of angle scan in a computer-modeled simulation of the IMD 600 configuration shown, which has six pointed return electrodes 526. Figure 3D The peak electric field observed in the configuration shown is 0.457 V / cm (or 45.7 V / m), as... Figure 4D The peak value is shown in the curve graph.

[0059] Figure 4E It is a diagram in the context of Figure 3EThe graph shows the electric field change at HB 224 as a function of angle scan in a computer-modeled simulation of the IMD 700 configuration shown, which has three inverted toothed return electrodes 726 positioned in non-invasive contact with the diaphragm. A peak electric field of 2.016 V / cm (or 201.6 V / m) was observed at HB 224 when 1 V was applied to the helical lead electrode 222. The useful angular therapeutic coverage of a single inverted toothed return electrode 726 is approximately 70 degrees with respect to the return electrode.

[0060] Figure 4F It is a diagram in the context of Figure 3F The graph shows the electric field change at HB 224 as a function of angle scan in a computer-modeled simulation of the IMD 800 configuration shown, which has six inverted pointed return electrodes 726. Figure 3F The peak electric field observed in the configuration shown is approximately 1.7 V / m (or 170 V / cm), as... Figure 4F The peak value is shown in the curve graph. Figure 4F In the curve diagram, there are two different peaks with zero position (~0.4v / m or 40v / cm) between the inverted tooth pairs. Therefore, an angular spacing of less than 60 degrees can help reduce the zero position depth.

[0061] Figure 5A and 5B The diagram illustrates an IMD 900, which can be configured as a lead-in-lead system according to aspects of this disclosure. The lead-in-lead system allows leads to be translated or rotated relative to each other to facilitate capture of desired portions of the patient's heart, such as the septal tissue near HB 224, or other specific capture targets. As the lead-in-lead system functions, the IMD 900 can provide a customized implantation plan for each patient.

[0062] The IMD 900 includes an outer lead 902 and an inner lead 906. The inner lead 906 extends through the lumen of the outer lead 902 (not shown). The IMD 900 includes various conductors (not shown) operatively coupled to electrodes. Any suitable conductor benefiting from this disclosure can be used to extend the implantable leads 902 and 906 through the IMD 900 using any suitable technique.

[0063] Multiple deep teeth 926A-926C (collectively referred to as "deep teeth 926") extend distally from the distal end 904 of the outer lead 902. The deep teeth 926 may be formed similarly to any deep teeth described herein and function similarly (e.g., as electrodes). The deep teeth 926 may be fixedly attached to the outer lead 902, or may be configured to be recessed into and extend from the distal end 904 of the outer lead 902. A shallow lead electrode 222, for example, in a helical form in the illustrated example, is coupled to the inner lead 906.

[0064] The IMD 900 can be delivered to the implantation site via a delivery catheter and / or sheath (not shown), which limits the deep cusps 926 to a pre-deployed configuration, e.g., extending distally substantially parallel to the longitudinal axis of the IMD 900. Upon advancement from the delivery catheter and / or sheath, the deep cusps 926 can be released into a pre-configured unfolding configuration and unfold laterally to each other as they penetrate cardiac tissue. The shallow lead electrode 222 can be screwed into or otherwise advanced into the cardiac tissue of the chamber in which the IMD 900 is implanted. In some example implantation procedures, the shallow lead electrode 222 can be engaged first, utilizing this fixation stability to allow for easier implantation of the deep cusps (or “deep-penetrating cusps”) 926. In some instances, the IMD 900 can be implanted using a corresponding procedure where the initial fixation step utilizes an inner / outer lead with fixation cusps instead of… Figure 5A and 5B The shallow lead electrode 222 shown is implemented in a spiral embodiment.

[0065] Figure 6 This is a flowchart illustrating an example technique for a lead system for implantation of leads according to aspects of this disclosure. Figure 6 Example techniques are in Figure 5A and 5B This is described in the context of IMD 900, but may be applied to other lead systems. According to Figure 6 In one instance, a delivery catheter or sheath for guiding the IMD 900 to a target implantation site in the heart is advanced to the target implantation site (1002). In some instances, the catheter is advanced to the target site, where the IMD 900 is positioned within its delivery lumen. In other instances, the catheter advances over a guidewire and the IMD 900 then advances through the lumen of the catheter.

[0066] according to Figure 6In some instances, the inner lead 906 is advanced to the target implantation site (1004). In some instances, the IMD 900 can be delivered with the inner lead 906 already advanced to the distal end of the delivery catheter, while in others, the inner lead 906 can be retracted from the distal end of the delivery catheter, for example, to protect patient tissue from the influence of electrode 222 during navigation to the target implantation site. Electrode 222 engages the target implantation site (1006). For example, the inner lead 906 can be advanced and rotated to advance electrode 222 away from the distal end of the delivery catheter and screw electrode 222 into the tissue at the target implantation site.

[0067] according to Figure 6 In one example, the deep cusp 926 is advanced away from the distal end of the delivery catheter, through the tissue at the target implantation site, and into deeper tissues, such as tissues near the hepatic hood (HB) or other conduction system tissues of the heart (1008). For example, the external lead 902 can advance over the internal lead 906 to advance the deep cusp 926 beyond the distal opening. As discussed herein, the deep cusps 926 can be constrained by the delivery catheter and achieve an unfolded shape as they are advanced from the catheter into the tissue, including being spaced apart from each other.

[0068] The following examples illustrate the techniques described herein.

[0069] Example 1A: An implantable medical device (IMD) includes: a plurality of deep cusps configured to advance into a septum of a patient's heart in different directions not parallel to the longitudinal axis of the implantable medical device, wherein each of the plurality of deep cusps is configured to deliver cardiac pacing to cardiac tissue distal to a cardiac chamber in which the IMD is implanted; and one or more shallow electrodes that can engage the septum, wherein the one or more shallow electrodes are configured to deliver cardiac pacing to the cardiac chamber in which the IMD is implanted.

[0070] Example 2A: The IMD according to Example 1A, wherein one or more shallow electrodes are configured to deliver atrial pacing therapy.

[0071] Example 3A: The IMD according to Example 1A, wherein one or more deep cusps are configured to deliver ventricular pacing therapy.

[0072] Example 4A: The IMD according to any one of Examples 1A-3A, wherein the deep cusps are configured to advance into the diaphragm up to the ventricular myocardium of the patient's heart.

[0073] Example 5A: The IMD according to any one of Examples 1A-4A, wherein the plurality of deep cusps are configured to deliver cardiac pacing to the His bundle (HB) of the patient's heart.

[0074] Example 6A: The IMD according to Example 5A, wherein the plurality of deep cusps are configured to deliver cardiac pacing to at least one of the left bundle branch (LBB) or right bundle branch (RBB) of the HB of the patient's heart.

[0075] Example 7A: The IMD according to any one of Examples 1A-6A, wherein the plurality of deep serrations are configured to be advanced into the diaphragm by piercing the diaphragm.

[0076] Example 8A: According to any one of Examples 1A-7A, the IMD wherein the plurality of shallow electrodes can be engaged with the diaphragm by piercing the diaphragm.

[0077] Example 9A: According to the IMD of Example 8A, wherein the plurality of shallow electrodes include corresponding shallow serrations, which, when in a deformed state, pierce the diaphragm to a first depth, the first depth being less than a second depth into which the plurality of deep serrations are configured to advance into the diaphragm.

[0078] Example 10A: According to any one of Examples 1A-9A, the plurality of shallow electrodes can be engaged with the diaphragm by non-invasive physical contact with the outer surface of the diaphragm.

[0079] Example 11A: According to any one of Examples 1A-10A, each of the plurality of deep cusps can be individually selected to deliver cardiac pacing in combination with at least one subset of the plurality of shallow electrodes.

[0080] Example 12A: According to any one of Examples 1A-11A, the IMD wherein the spacing between adjacent deep cusps in the plurality of deep cusps is in the range of 30 degrees to 180 degrees.

[0081] Example 1B: An implantable medical device (IMD) includes: a deep electrode configured to be advanced into a septum of a patient's heart; and a plurality of shallow cusps that can engage with the septum, a subset of the plurality of shallow cusps being selectable to form one or more return electrodes configured to deliver pacing therapy to a target site within the septum in series with a helical lead electrode.

[0082] Example 2B: The IMD according to Example 1B, wherein the deep electrode includes a spiral lead electrode.

[0083] Example 3B: The IMD according to Example 1B, wherein the pacing therapy includes ventricular pacing therapy.

[0084] Example 4B: The IMD according to any one of Examples 1B-3B, wherein the deep electrode is configured to be advanced into the diaphragm up to the ventricular myocardium of the patient's heart.

[0085] Example 5B: IMD according to any one of Examples 1B-4B, wherein the target site includes the His bundle (HB) of the patient's heart.

[0086] Example 6B: The IMD according to Example 5B, wherein the deep electrode is configured to deliver cardiac pacing to at least one of the left bundle branch (LBB) or right bundle branch (RBB) of the patient's heart HB.

[0087] Example 7B: The IMD according to any one of Examples 1B-6B, wherein the deep electrode is configured to be advanced into the diaphragm by piercing the diaphragm.

[0088] Example 8B: According to the IMD of Example 7B, the plurality of shallow serrations can engage with the diaphragm by piercing the diaphragm.

[0089] Example 9B: According to the IMD of Example 8B, wherein the plurality of shallow serrations, when in a deformed state, pierce the diaphragm to a first depth, the first depth being less than the second depth to which the deep electrode pierces the diaphragm.

[0090] Example 10B: According to any one of Examples 1B-7B, the plurality of shallow serrations can be engaged with the diaphragm by non-invasive physical contact with the outer surface of the diaphragm.

[0091] Example 11B: The IMD according to Example 10B, wherein the plurality of shallow serrations are protruding relative to the outer surface of the diaphragm when in the corresponding deformed position.

[0092] Example 12B: The IMD according to Example 10B, wherein the plurality of shallow serrations are recessed relative to the outer surface of the diaphragm when in the corresponding deformed position.

[0093] Example 13B: According to any one of Examples 1B-12B, the plurality of shallow cusps comprises a total of three (3) shallow cusps.

[0094] Example 14B: The IMD according to any one of Examples 1B-12B, wherein the plurality of shallow cusps comprises a total of six (6) shallow cusps.

[0095] Various examples of this disclosure have been described. Consider any combination of the described systems, operations, or functions. These and other examples are within the scope of the following claims.

Claims

1. An implantable medical device (IMD) comprising: Multiple deep cusps are configured to advance into the septum of a patient’s heart in different directions not parallel to the longitudinal axis of the implantable medical device, wherein each of the multiple deep cusps is configured to deliver cardiac pacing to cardiac tissue distal to the cardiac chamber in which the IMD is implanted. and One or more shallow electrodes are configured to transition from a deformed state to an undeformed state to engage with the diaphragm, wherein the one or more shallow electrodes are configured to deliver cardiac pacing to the cardiac chamber implanted in the IMD.

2. The implantable medical device of claim 1, wherein the one or more superficial electrodes are configured to deliver atrial pacing therapy, and the deep canines are configured to deliver ventricular pacing therapy.

3. The implantable medical device according to claim 1 or 2, wherein the deep cusps are configured to be advanced into the diaphragm to the ventricular myocardium of the patient's heart.

4. The implantable medical device according to claim 1 or 2, wherein the plurality of deep cusps are configured to deliver cardiac pacing to at least one of the left bundle branch (LBB), right bundle branch (RBB), or His bundle (HB) of the patient's heart.

5. The implantable medical device according to claim 1 or 2, wherein the one or more shallow electrodes can be engaged with the septum by puncturing the septum.

6. The implantable medical device of claim 5, wherein the one or more shallow electrodes include a plurality of shallow serrations, wherein, in the undeformed state, the shallow serrations are configured to pierce the septum to a first depth, the first depth being less than a second depth to which the plurality of deep serrations are configured to advance into the septum.

7. The implantable medical device of claim 1 or 2, wherein the one or more shallow electrodes comprise a plurality of shallow electrodes that can be engaged with the diaphragm by non-invasive physical contact with the outer surface of the diaphragm.

8. The implantable medical device of claim 1 or 2, wherein each of the plurality of deep cusps can be individually selected to combine with at least one of the one or more shallow electrodes to deliver the cardiac pacing.

9. The implantable medical device according to claim 1 or 2, wherein the spacing between adjacent deep cusps in the plurality of deep cusps is in the range of 30 degrees to 180 degrees.

10. The implantable medical device according to claim 1 or 2, further comprising: Includes an external lead for the lumen, wherein the plurality of deep serrations extend from the distal end of the external lead; and An inner lead configured to move within the lumen of the outer lead, wherein one or more shallow electrodes are located at the distal end of the inner lead.

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