Implantable medical lead with shield

Abstract

The present disclosure describes implantable medical leads and medical device systems utilizing the same. In some examples, an implantable medical lead includes a first defibrillation electrode and a second defibrillation electrode configured to deliver anti-tachyarrhythmia shocks, and a pacing electrode disposed between the first and second defibrillation electrodes and configured to deliver pacing pulses that generate an electric field in proximity to the pacing electrode. The implantable medical lead further includes a shield disposed between the first and second defibrillation electrodes and over a portion of an outer surface of the pacing electrode, wherein the shield is configured to block the electric field in a direction from the pacing electrode away from a heart.

Description

[0001] This application claims the benefits of U.S. Application Serial No. 17 / 185,784, filed February 25, 2021, and U.S. Provisional Application Serial No. 62 / 982,790, filed February 28, 2020, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to implantable medical leads, and more specifically, to implantable medical leads having one or more structures to reduce the likelihood of irritation to unintended tissues. Background Technology

[0003] Malignant tachyarrhythmias, such as ventricular fibrillation (VF), are uncoordinated contractions of the myocardium in the ventricles of the heart and are the most common arrhythmia in patients with cardiac arrest. If such arrhythmia lasts longer than a few seconds, it can lead to cardiogenic shock and the cessation of effective blood circulation. Therefore, sudden cardiac death (SCD) can occur within minutes.

[0004] In patients at high risk of VF, the use of implantable systems, such as implantable cardioverter-defibrillator (ICD) systems, has been shown to be beneficial in preventing SCD. Implantable systems, such as pacemakers with or without cardioversion or defibrillation capabilities, can also treat other cardiac dysfunctions, such as bradycardia and heart failure. These implantable systems may include an electrical device configured to deliver treatment via electrodes. Treatment may include electric shock and / or antitachycardia pacing (ATP). Implantable systems may also be configured to deliver cardiac pacing for example, to treat bradycardia or for cardiac resynchronization therapy (CRT).

[0005] An implantable system may include one or more implantable medical leads. The distal portion of the implantable medical lead may include one or more electrodes and may be positioned at a target location within the patient's body for delivering electrical therapy and / or electrical sensing via the electrodes. The proximal end of the lead may be coupled to the implantable system. The implantable system may also include one or more shell electrodes, sometimes referred to as canister electrodes, for delivering therapy and / or sensing.

[0006] Due to the inherent surgical risks of attaching and replacing implantable medical leads directly within or on the heart, subcutaneous implantable systems have been designed, in which the implantable system and lead are located subcutaneously on the lateral side of the thorax. It has also been proposed that the distal portion of the lead of the implantable system be implanted within the thorax but not in contact with the heart, for example, under the sternum. Furthermore, it has been proposed that the distal portion of the lead of the implantable system be implanted within extracardiac vessels within the thorax, such as the internal thoracic vein (ITV), intercostal veins, epigastric wall veins, or azygos vein, hemiazygos vein, and accessory hemiazygos vein.

[0007] Implantable medical leads are also used to deliver treatment to tissues other than the heart. Implantable medical leads can be used to position one or more electrodes within or near target nerves, muscles, or organs to deliver electrical stimulation to these tissues. For example, implantable medical leads can be positioned in the epidural space to deliver spinal cord stimulation, or near other nerves such as the pelvic nerves or renal nerves to deliver nerve stimulation. Summary of the Invention

[0008] Compared to electrodes placed on or inside the heart, delivering pacing pulses using extravascular leads requires significantly higher energy levels to capture the heart. Furthermore, conventional pacing electrodes placed outside the blood vessel can divert most of the electric field generated by the pacing pulse away from the heart. This diverted electric field can stimulate extracardiac tissues, such as the phrenic nerve, nerve endings in the intercostal region, or other sensory or motor nerves. Similar problems can occur when electrodes are implanted in extracardiac vessels within the thoracic cavity, such as the ITV, intercostal veins, epigastric veins, or the azygos, hemiazygos, and accessory hemiazygos veins, or when electrodes are implanted in other extracardiac locations.

[0009] This disclosure describes implantable medical leads and implantable systems utilizing leads, such as ICD systems. More specifically, this disclosure describes implantable medical leads including a shield configured to block the electric field from pacing pulses, for example, by blocking or reducing the electric field in the direction away from the pacing electrodes, such as in the forward direction. In this way, the shield can reduce the likelihood that pacing pulses delivered via the pacing electrodes will stimulate extracardiac tissues such as sensory or motor nerves, which can reduce pain or other sensations associated with capturing such tissues. Furthermore, the shield can direct the electric field toward the heart, allowing pacing pulses of lower energy levels to capture the heart compared to what might be necessary without the shield. Lower energy pacing pulses can also reduce the likelihood of pacing pulses delivered via the pacing electrodes stimulating extracardiac tissues and can result in less power consumption of the ICD, and thus extend the lifespan of the ICD.

[0010] Although this document is primarily described in the context of ICD systems, various aspects of the technology disclosed herein can be applied to implantable systems other than ICD systems, including, but not limited to, bradycardia or CRT pacemaker systems. Therefore, implantable medical leads with one or more shielding elements can be used in contexts other than ICD systems, including both cardiac and non-cardiac applications. As an example, an implantable medical lead with a shielding element above a portion of the electrode surface can be used with an external pacemaker system that does not have defibrillation capabilities. As another example, an implantable medical lead with a shielding element above a portion of the electrode surface can prevent the electric field generated by the delivery of nerve stimulation by the electrodes in a direction away from the target nerve. In this way, the shielding element can direct nerve stimulation to the intended tissue and reduce the likelihood of nerve stimulation stimulating unintended tissue.

[0011] In one example, the implantable medical lead includes: a first defibrillator electrode and a second defibrillator electrode configured to deliver an anti-tachyarrhythmic shock; and a pacing electrode disposed between the first and second defibrillator electrodes, configured to deliver pacing pulses that generate an electric field in the vicinity of the pacing electrode. The implantable medical lead further includes a shield disposed between the first and second defibrillator electrodes, above a portion of the outer surface of the pacing electrode, and extending laterally away from the pacing electrode, wherein the shield is configured to block the electric field in the direction from the pacing electrode away from the heart.

[0012] In another example, an implantable cardioverter defibrillator (ICD) system includes an implantable medical lead as described above and an ICD configured to deliver pacing pulses via pacing electrodes.

[0013] In another example, the method of implanting an implantable medical lead as described above includes advancing the implantable medical lead to a location within the patient's body and rotatably orienting the distal portion of the implantable medical lead such that the shield is opposite the pacing electrode to the heart.

[0014] In another example, a method of manufacturing an implantable medical lead as described above includes attaching a shield to the surface of a pacing electrode, and subsequently assembling the shield and the pacing electrode onto the implantable medical lead.

[0015] The present invention is intended to provide an overview of the subject matter described herein. It is not intended to provide an exclusive or exhaustive explanation of the systems, apparatus, and methods described in detail in the accompanying drawings and description below. Further details of one or more examples are set forth in the accompanying drawings and description below. Other features, objects, and advantages will become apparent from the description and drawings provided below, as well as the statements made therein. Attached Figure Description

[0016] Figure 1A A frontal view of a patient with an intrathoracic implanted extracorporeal ICD system.

[0017] Figure 1B A side view of a patient with an intrathoracic implanted extracorporeal ICD system.

[0018] Figure 1C A transverse view of a patient with an intrathoracic implanted extracorporeal ICD system.

[0019] Figure 2 A conceptual diagram illustrating the distal portion of an example implantable medical lead, including a shielding element.

[0020] Figures 3A-3CA conceptual diagram illustrating an example shielding device for implantable medical leads.

[0021] Figure 4 A flowchart illustrating an example technique for implanting an implantable medical lead, including a shielding element.

[0022] Figure 5 A flowchart illustrating an example technique for manufacturing implantable medical leads, including shielding components.

[0023] Figure 6 A conceptual diagram illustrating the distal portion of an example implantable medical lead that includes multiple shielding elements.

[0024] Figure 7 A conceptual diagram illustrating the distal portion of an implantable medical lead, which includes multiple shielding elements.

[0025] Figure 8 A conceptual diagram illustrating the distal portion of an implantable medical lead, which includes a shielding element.

[0026] Figure 9 A conceptual diagram illustrating a portion of the distal part of another implantable medical lead, including a shield.

[0027] Figure 10 A functional block diagram of the electronic components of the instance ICD. Detailed Implementation

[0028] As used herein, relational terms such as “first” and “second”, “above” and “below”, “front” and “rear” may be used only to distinguish one entity or element from another, without requiring or implying any physical or logical relationship or order between such entities or elements.

[0029] Now refer to the attached drawings where the same reference indicators refer to the same components. Figure 1A -C shows a conceptual diagram illustrating various views of an example of an implantable cardioverter defibrillator (ICD) system 8. The ICD system 8 includes an ICD 9 connected to an implantable medical lead 10. Figure 1A A frontal view of a patient with an implanted extravascular ICD system 8. Figure 1B A side view of a patient with an implanted extravascular ICD system 8. Figure 1C A transverse view of a patient with an implanted extravascular ICD system 8.

[0030] The ICD 9 may include a hermetically sealed housing forming components that protect the ICD 9. The housing of the ICD 9 may be formed of a conductive material, such as titanium or a titanium alloy, which may serve as housing electrodes (sometimes referred to as can electrodes). In some embodiments, the ICD 9 may be formed to have or may include multiple electrodes on the housing. The ICD 9 may also include a connector assembly (also referred to as a connector block or plug) containing an electrical feedthrough through which an electrical connection is made between the conductor of the lead 10 and electronic components contained within the housing of the ICD 9. As will be further described in detail herein, the housing may house one or more processors, memories, transmitters, receivers, sensors, sensing circuitry, therapeutic circuitry, power supplies, and other suitable components. The housing is configured for implantation in a patient, such as patient 12.

[0031] ICD-9 is implanted outside the left thoracic cavity, such as under the skin and outside the thoracic cavity (subcutaneous or submuscular). In some cases, ICD-9 may be implanted between the left posterior axillary line and the left anterior axillary line. However, as described later, ICD-9 may be implanted in other extrathoracic locations.

[0032] Lead 10 may include an elongated lead body 13, the distal portion 16 of which is sized for implantation in an extracardiac location near the heart, such as within the thoracic cavity. Figure 1A As described in -C, or outside the thoracic cavity. For example, the lead 10 may extend from the ICD 9 toward the center of the patient's trunk, for example, toward the patient's xiphoid process 23, subcutaneously and extrathoracically (e.g., subcutaneously or submuscularly) to the outside of the thoracic cavity. At a location near the xiphoid process 23, the lead body 13 may be bent or otherwise rotated and extended upwards. The bending may be pre-formed and / or the lead body 13 may be flexible to facilitate bending. Figure 1A In the example described in -C, the lead body 13 extends upward within the thorax below the sternum in a direction substantially parallel to the sternum.

[0033] In one instance, the distal portion 16 of the lead 10 may be located substernal, such that the distal portion 16 of the lead 10 extends substantially upward along the posterolateral aspect of the sternum within the anterior mediastinum 36. The anterior mediastinum 36 may be considered to be laterally defined by the pleura 39, posteriorly defined by the pericardium 38, and anteriorly defined by the sternum 22. In some cases, the anterior wall of the anterior mediastinum 36 may also be formed by the transverse thoracic muscle and one or more costal cartilages. The anterior mediastinum 36 contains a large amount of loose connective tissue (such as celluloid), adipose tissue, some lymphatic vessels, lymph nodes, substernal muscle tissue (e.g., transverse pectoral muscles), thymus, branches of the internal thoracic artery, and the ITV.

[0034] In another example, the lead body 13 may extend upwards to the outside of the thorax (rather than within the thorax), for example, subcutaneously or submuscularly above the sternum / sternum. The lead 10 may be implanted in other locations, such as above the sternum, offset to the right of the sternum, or laterally tilted from the proximal or distal end of the sternum. In other examples, the lead 10 may be implanted within extracardiac vessels within the thorax, such as the ITV, intercostal veins, epigastric veins, or azygos vein, hemiazygos vein, and accessory hemiazygos vein. In some examples, the orientation of the distal portion 16 of the lead 10 may differ from that of other vessels. Figure 1A-1C The orientation described herein may be orthogonal to or otherwise transverse to the sternum 22 and / or below the heart 26. In such instances, the distal portion 16 of the lead 10 may be at least partially within the anterior mediastinum 36.

[0035] The lead body 13 may have a generally tubular or cylindrical shape and may define a diameter of approximately 3-9 Frenchies (Fr). However, lead bodies with diameters less than 3 Fr and greater than 9 Fr may also be used. In another configuration, the lead body 13 may have a flat, strip-like, or paddle-like shape along at least a portion of its length, having a solid woven filament or mesh structure. In such examples, the width across the lead body 13 may be between 1 and 3.5 mm. Other lead body designs may be used without departing from the scope of this application.

[0036] The lead body 13 may be formed of a non-conductive material comprising silicone, polyurethane, fluoropolymers, mixtures thereof, and other suitable materials, and shaped to form one or more cavities (not shown); however, the technology is not limited to this type of construction. The distal portion 16 may be manufactured to be biased into a desired configuration, or alternatively, manipulated by a user into a desired configuration. For example, the distal portion 16 may be made of a malleable material, allowing a user to manipulate the distal portion into a desired configuration that remains unchanged until manipulated into a different configuration.

[0037] The lead body 13 may include a proximal end 14 and a distal portion 16, the distal portion containing electrodes configured to deliver electrical energy to the heart or sense electrical signals from the heart. The distal portion 16 can be anchored to a desired location within the patient's body, such as substernal or subcutaneous, for example, by suturing the distal portion 16 to the patient's muscle, tissue, or bone at the xiphoid process entry site. In some instances, the distal portion 16 may be anchored to the patient or by using rigid serrations, tips, barbs, clips, screws, and / or other protruding elements or flanges, discs, compliant serrations, flaps, porous structures such as mesh elements, and metallic or non-metallic scaffolds that promote tissue growth for engagement, bioadhesive surfaces, and / or any other non-puncture elements.

[0038] The lead body 13 defines a substantially linear portion 20 when it bends or curves near the xiphoid process 23 and extends upward. Figure 1A ).like Figure 1A As shown, at least a portion of the distal portion 16 may define a wavy configuration distal to the substantially linear portion 20. Specifically, the distal portion 16 may define a wavy pattern, such as a zigzag, zigzag, sinusoidal, serpentine, or other pattern, as it extends toward the distal end of the lead 10. In other configurations, the lead body 13 may not have a substantially linear portion 20 as it extends upwards, but may begin a wavy configuration immediately after bending.

[0039] The distal portion 16 includes one or more defibrillation electrodes configured to deliver an anti-tachyarrhythmia, such as cardioversion / defibrillation, shock to the heart 26 of the patient 12. In some instances, the distal portion 16 includes a plurality of defibrillation electrodes spaced apart from each other along the length of the distal portion 16. Figure 1A-1C In the illustrated example, the distal portion 16 contains two defibrillation electrodes 28a and 28b (collectively referred to as “defibrillation electrodes 28”).

[0040] The defibrillation electrode 28 may be disposed around or within the lead body 13 of the distal portion 16, or alternatively, may be embedded within the wall of the lead body 13. In one configuration, the defibrillation electrode 28 may be a coil electrode formed of a conductor. The conductor may be formed of one or more conductive polymers, ceramics, metal-polymer composites, semiconductors, metals, or metal alloys, including, but not limited to, combinations of platinum, tantalum, titanium, niobium, zirconium, ruthenium, indium, gold, palladium, iron, zinc, silver, nickel, aluminum, molybdenum, stainless steel, MP35N, carbon, copper, polyaniline, polypyrrole, and other polymers. In another configuration, each of the defibrillation electrodes 28 may be a flat strip electrode, a paddle electrode, a braided or woven electrode, a mesh electrode, a directional electrode, a patch electrode, or another type of electrode configured to deliver a cardioversion / defibrillation shock to the heart 26 of the patient 12.

[0041] In one configuration, the defibrillation electrodes 28 are spaced approximately 0.25–4.5 cm apart, and in some cases 1–3 cm apart. In another configuration, the defibrillation electrodes 28 are spaced approximately 0.25–1.5 cm apart. In yet another configuration, the defibrillation electrodes 28 are spaced approximately 1.5–4.5 cm apart.

[0042] exist Figure 1A-1CIn the configuration shown, the defibrillator 28 spans a large portion of the distal portion 16. The length of each of the defibrillator 28 may be between approximately 1-10 cm, between approximately 2-6 cm, or between approximately 3-5 cm. However, according to the art of this disclosure, lengths greater than 10 cm and less than 1 cm may be utilized. The total length of the defibrillator electrodes on the distal portion 16, such as the length of two combined defibrillator electrodes 28, may vary according to several variables. In one example, the total length may be between approximately 5-10 cm. However, in other embodiments, the defibrillator electrodes 28 may have a total length of less than 5 cm and greater than 10 cm. In some cases, the defibrillator electrodes 28 may have substantially the same length, or alternatively, different lengths.

[0043] The defibrillator electrodes 28 may be electrically connected to one or more conductors, which may be disposed within the body wall of the lead body 13 or within one or more insulating cavities (not shown) defined by the lead body 13. In an example configuration, each of the defibrillator electrodes 28 is connected to a common conductor, such that voltage can be applied simultaneously to all defibrillator electrodes 28 to deliver an anti-tachyarrhythmic shock to the heart 26. In other configurations, the defibrillator electrodes 28 may be attached to individual conductors, such that each defibrillator electrode 28 can be voltage-applied independently of the other defibrillator electrodes 28. In this case, the ICD 9 or lead 10 may include one or more switches or other mechanisms to electrically connect the defibrillator electrodes together as a common polarity electrode, such that voltage can be applied simultaneously to all defibrillator electrodes 28 in addition to being able to be applied independently.

[0044] The distal portion 16 may also include one or more pacing and / or sensing electrodes configured to deliver pacing pulses to the heart 26 and / or sense the electrical activity of the heart 26. Such electrodes may be referred to as pacing electrodes, sensing electrodes, or pacing / sensing electrodes. Figure 1A-1C In the illustrated example, the distal portion 16 includes two pacing / sensing electrodes 32a and 32b (collectively referred to as "pacing / sensing electrodes 32").

[0045] In the illustrated example, the pacing / sensing electrode 32b is positioned between the defibrillation electrodes 28, for example, within the gap between the defibrillation electrodes, and the pacing / sensing electrode 32a is positioned closer along the distal portion 16 than the proximal defibrillation electrode 28a. In some examples, more than one electrode 32 may be present within the gap between the defibrillation electrodes 28. In some examples, the electrode 32 is additionally or alternatively located distal to the distal defibrillation electrode 28b.

[0046] In one example, the distance between the nearest defibrillator electrode 28 and electrode 32 is greater than or equal to approximately 2 mm and less than or equal to approximately 1.5 cm. In another example, electrode 32 may be spaced from the nearest defibrillator electrode 28 by greater than or equal to 5 mm and less than or equal to 1 cm. In yet another example, electrode 32 may be spaced from the nearest defibrillator electrode 28 by greater than or equal to 6 mm and less than or equal to 8 mm.

[0047] Electrode 32 may be configured to deliver low-voltage electrical pulses to the heart or to sense cardiac electrical activity, such as cardiac depolarization and repolarization. Therefore, electrode 32 may be referred to herein as pacing / sensing electrode 32. In one configuration, electrode 32 is a ring electrode. However, in other configurations, electrode 32 may be any of a variety of different types of electrodes, including ring electrodes, short coil electrodes, paddle electrodes, hemispherical electrodes, or directional electrodes. Each of electrode 32 may be the same as or a different type of electrode than the other electrode 32. Electrode 32 may be electrically isolated from adjacent defibrillation electrodes 28 by including an electrically insulating layer of material between electrode 32 and adjacent defibrillation electrodes 28. Each electrode 32 may have its own separate conductor, such that a voltage can be applied to or sensed via each electrode independently of the other electrode 32.

[0048] Electrode 28 is referred to as a defibrillation electrode, and electrode 32 as a pacing / sensing electrode, as they can have different physical structures to achieve different functions. Defibrillation electrode 28 can be larger than pacing / sensing electrode 32, for example, having a larger surface area, and can therefore be configured to deliver anti-tachyarrhythmic shocks with relatively higher voltages than pacing pulses. The relatively smaller size of pacing / sensing electrode 32 can provide advantages over defibrillation electrode for delivering pacing pulses and sensing intrinsic cardiac activity, such as a lower pacing capture threshold and / or better sensing signal quality. However, defibrillation electrode 28 can be used to deliver pacing pulses and / or sense the electrical activity of the heart, as in combination with pacing / sensing electrode 32.

[0049] exist Figure 1A-1C In the configuration shown, each electrode 32 is substantially aligned along a main longitudinal axis (“x”). In one example, the main longitudinal axis is defined by a portion of an elongated body 12, such as a substantially linear portion 20. In another example, the main longitudinal axis is defined relative to the patient’s body, such as along the anterior midline (or sternal midline), one of the sternal lines (or lateral sternal line), the left parasternal line, or other lines.

[0050] In one configuration, the midpoint of each electrode 32a and 32b is along the main longitudinal axis "x", such that when the distal portion is implanted in the patient, each electrode 32a and 32b is positioned at at least substantially the same horizontal level. In some instances, the longitudinal axis "x" may correspond to the patient's caudal axis, and a horizontal axis orthogonal to the longitudinal axis "x" may correspond to the patient's medial or lateral axis. In other configurations, the electrode 32 may be positioned at any longitudinal or horizontal position along the distal portion 16, located between, proximal to, or distal to the defibrillation electrodes 28. Figure 1A In the example illustrated, electrode 32 is positioned along the wavy configuration of the distal portion 16 at a location closer to the heart 26 of the patient 12 than defibrillation electrode 28 (e.g., at the peak of the wavy configuration toward the left side of the sternum). Figure 1A As illustrated, for example, electrodes 32 are substantially aligned with each other along the left sternal line. Figure 1A In the example illustrated, the defibrillator 28 is positioned with peaks in a wavy configuration extending toward the right side of the sternum away from the heart. This configuration places the pacing / sensing electrode 32 closer to the heart than the electrode 28 to facilitate cardiac pacing and sensing at a relatively low amplitude.

[0051] In some instances, when the distal portion 16 is implanted outside the cardiovascular system, the pacing / sensing electrode 32 and the defibrillation electrode 28 may be positioned in a common plane. In other configurations, the wavy arrangement may not be substantially positioned in a common plane. For example, the distal portion 16 may define a concavity or curvature.

[0052] The proximal end 14 of the lead body 13 may include one or more connectors 34 to electrically couple the lead 10 to the ICD 9. The ICD 9 may also include a connector assembly containing an electrical feedthrough through which an electrical connection is made between the one or more connectors 34 of the lead 10 and electronic components contained within the housing. The housing of the ICD 9 may house one or more processors, memories, transmitters, receivers, sensors, sensing circuitry, therapeutic circuitry, power supplies (capacitors and batteries), and / or other components. The components of the ICD 9 may generate and deliver electrical therapy, such as antitachycardia pacing, cardioversion or defibrillation shocks, post-shock pacing, and / or bradycardia pacing.

[0053] The wavy configuration of the distal portion 16 and the inclusion of electrodes 32 between the defibrillator electrodes 28 provide multiple therapeutic vectors for delivering electrical therapy to the heart. For example, at least a portion of the defibrillator electrodes 28 and one of the electrodes 32 may be positioned above the right ventricle or any chamber of the heart, such that pacing pulses and anti-tachyarrhythmic shocks can be delivered to the heart. The housing of the ICD9 may be charged to or used as a polarity different from that of one or more defibrillator electrodes 28 and / or electrodes 32, such that electrical energy can be delivered to the heart between the housing and the defibrillator electrodes 28 and / or electrodes 32.

[0054] When voltage is applied to each defibrillator 28, each defibrillator may have the same polarity as each of the other defibrillator 28, allowing a shock to be delivered from all defibrillation shocks together. In instances where the defibrillator 28 is electrically connected to a common conductor within the lead body 13, this is the only configuration of the defibrillator 28. However, in other instances, the defibrillator 28 may be coupled to individual conductors within the lead body 13, and thus may each have a different polarity, allowing electrical energy to flow between the defibrillator 28, or between one of the defibrillator 28 and one of the pacing / sensing electrodes 32 or the housing electrode, to provide anti-tachyarrhythmic shocks, pacing therapy, and / or sensing cardiac depolarization. In this case, the defibrillator 28 may still be electrically coupled together, for example, via one or more switches within the ICD 9, to have the same polarity.

[0055] In some instances, the distal portion 16 of the lead 10 may include one or more shields. These shields may be configured to prevent the electric field from delivering electrical therapy via the electrodes, for example, from pacing pulses, in a direction away from the heart, such as in the forward direction. In this way, the shields reduce the likelihood that the electric field will stimulate extracardiac tissues, such as sensory or motor nerves. Furthermore, the shields can direct the electric field toward the heart, allowing lower energy levels of pacing pulses to capture the heart compared to what might be necessary without shielding. Lower energy pacing pulses also reduce the likelihood that pacing pulses delivered via the pacing electrodes will stimulate extracardiac tissues and can result in less power consumption for the ICD 9, and thus extend the ICD's lifespan. It should be understood that various aspects of the techniques disclosed herein can be applied to implantable systems other than the ICD 9, including, but not limited to, bradycardia pacemaker systems. For example, a lead without defibrillation electrodes may include one or more shields and may be used with pacemaker systems that do not have defibrillation capabilities.

[0056] Figure 2 A conceptual diagram illustrating an example configuration of the distal portion 16 of an implantable medical lead 10. (See diagram below.) Figure 2 As explained, the wavy configuration of the distal portion 16 may include multiple peaks along the length of the distal portion. Figure 2 In the illustrated example, the distal portion contains three peaks 24a, 24b, and 24c (collectively referred to as "peak 24"). However, other configurations may contain any number of peaks 24.

[0057] The wavy configuration can define an interpeak distance 35, the length of which along the distal portion 16 can be variable or constant. In the configuration illustrated in Figures 1-2, the wavy configuration defines a basic sinusoidal configuration with a constant interpeak distance 35 of approximately 2.0–5.0 cm. The wavy configuration can also define an interpeak width 37, the length of which along the wavy configuration can also be variable or constant. In the configuration illustrated in Figures 1-2, the wavy configuration defines a basic sinusoidal shape with a constant interpeak width 37 of approximately 0.5–2.0 cm. However, in other cases, the wavy configuration can define other shapes and / or patterns, such as S-shapes, waveforms, etc.

[0058] The defibrillator 28 may extend along, for example, a large portion of the wavy configuration disposed on or covering the distal portion 16, for example, along at least 80% of the wavy portion. The defibrillator 28 may extend along more or less 80% of the wavy configuration. As another example, the defibrillator 28 may extend along at least 90% of the wavy configuration.

[0059] The defibrillator electrode 28a extends from the proximal end to the peak 24b along a substantial portion of the wavy arrangement of the distal portion 16, for example, along a substantial portion of the first "wave" associated with the peak 24a, and the defibrillator electrode segment 28b extends from the peak 24b to the distal end of the wavy arrangement along a substantial portion of the wavy arrangement, for example, along a substantial portion of the second "wave" associated with the peak 24c. In the example illustrated in Figures 1-2, a portion of the wavy arrangement on which the defibrillator electrode 28 is not disposed is the gap between the defibrillator electrodes 28a and 28b on the peak 24b where the electrode 32b is disposed.

[0060] As by Figure 2 As illustrated, the distal portion 16 of lead 10 may include a shield 30. In the illustrated example, similar to the pacing / sensing electrode 32b, the shield 30 is positioned between the defibrillation electrodes 28a and 28b, for example, on the wavy peak 24b of the distal portion 16. The shield 30 covers or is otherwise disposed on a portion of the outer surface of the pacing / sensing electrode 32b. The shield 30 does not cover the entire outer surface of the pacing / sensing electrode 32b.

[0061] The pacing pulse delivered by the ICD 9 via the pacing / sensing electrode 32b generates an electric field near the electrode that "diffuses" from the electrode surface toward one or more other electrodes used to deliver the pacing pulse. The shield 30 blocks the electric field in the direction from the electrode toward the shield and allows it to diffuse in the direction from the electrode away from the shield. In this way, The shield 30 is configured to give the pacing / sensing electrode 32b directionality. .

[0062] like Figure 2As described, the shield 30 may extend laterally away from the pacing / sensing electrode 32b, for example, in a substantially planar manner, such that the dimension of the shield 30 in the plane is larger than the dimension of the pacing / sensing electrode 32b in the plane. In this way, the shield 30 may additionally (or more effectively) limit the diffusion direction, such as the radial angle, of the electric field generated by the pacing pulse from the pacing / sensing electrode 32b. The plane in which the shield 30 extends laterally from the pacing / sensing electrode 32b may be the same plane extending from the wavy peak 24, or a substantially parallel plane. In some instances, such as those described by… Figure 2 As described, the shield 30 extends symmetrically from the pacing / sensing electrode 32b, for example, symmetrical about the longitudinal and / or transverse axes of the pacing / sensing electrode 32b, such that the pacing / sensing electrode 32b is substantially centered in the plane within the outer contour of the shield 30.

[0063] The portion of the shield 30 on the outer surface of the pacing / sensing electrode 32b may be referred to as the "forward portion" of the outer surface of the pacing / sensing electrode 32b, because this portion can be positioned further forward within the patient's body when the distal portion 16 of the lead 10 is implanted. When the shield 30 is positioned above the forward portion of the outer surface of the pacing / sensing electrode 32b, the shield 30 can be positioned forward relative to the central longitudinal axis of the pacing / sensing electrode 32b. Figure 1A-1C As explained, when the shield 30 is positioned above the forward portion of the outer surface of the pacing / sensing electrode 32b and the distal portion 16 is implanted into the patient, the shield 30 can prevent the electric field in the direction away from the heart 26, referred to as the forward direction.

[0064] The shield 30 may be electrically insulating. In some instances, the shield 30 comprises a polymer, such as polyurethane. In some instances, the shield 30 is configured to fold or wrap around the pacing / sensing electrode 32b for delivery via the cavity of the implantation tool, and is configured to elastically defold or unfold to a relaxed state upon release from the cavity, for example, as shown in the image. Figure 2 The state is shown. In some instances, the shield 30 includes an elastic or hyperelastic polymer or metal structure, such as a nitinol structure, to facilitate the deployment of the shield 30, support the hinges of the shield 30, and / or support the shield 30 in a deployed, relaxed configuration. The deployed and / or hinged configuration can be substantially planar, such as... Figure 2 As described herein, it may also be non-planar. For example, the portion of the shield 30 that is laterally spaced further away from the pacing / sensing electrode 32b may be positioned further back, for example, in a cup or bowl shape, compared to the portion closer to the electrode.

[0065] Such support structures may be partially or completely embedded within the main material of the shield 30, or attached to one or more outer surfaces of the shield 30. In some instances, the support structures are circumferentially positioned around the periphery of the shield 30, for example, at a maximum lateral distance from the shield. However, other support structure locations are also possible. For example, one or more support structures may extend radially or laterally from the electrode, for example, from near the electrode to near the periphery of the shield.

[0066] Figures 3A-3C This is a conceptual diagram illustrating the view of the shield 30 of the implantable medical lead 10. Specifically, Figure 3A This describes the "top" view in the forward direction. Figure 3B Describe the side view, and Figure 3C In order to be in Figure 3B The cross-sectional view taken by line AA in the figure.

[0067] like Figure 3A and 3B As described, the shield 30 may extend from the distal end 41a of the proximal defibrillator 28a to the proximal end 41b of the distal defibrillator 28b in the direction of the longitudinal axis "x" of the distal portion 16. In some embodiments, the shield 30 may extend over part or all of one or both of the defibrillator electrodes 28. In some embodiments, the shield 30 may not extend to one or both of the defibrillator electrodes 28, thus leaving a gap between the shield and the defibrillator electrodes.

[0068] Figure 3A and 3C This describes the shield 30 that extends laterally away from the pacing / sensing electrode 32b. For example... Figure 3A As shown, the shielding element 30 may be substantially circular in the plane in which it extends. In other examples, the shielding element 30 may have other shapes, such as oval or rectangular.

[0069] The length 44 of the shield 30 is greater than the length 45 of the pacing / sensing electrode 32b, such as at least twice the length of the pacing / sensing electrode 32b. The width 46 of the shield 30 is greater than the width 47 of the pacing / sensing electrode 32b, such as at least twice the width 47 of the pacing electrode. In some instances, the shield 30 extends beyond the pacing / sensing electrode 32b by a distance 48 in its width direction, for example, in a direction orthogonal to its longitudinal axis. In some instances, the distance 48 is at least 5 mm, at least 7 mm, or at least 9 mm. One or both of the length 44 and width 46 of the shield 30 may be at least 15 mm, such as approximately 20 mm. In instances where the shield 30 is circular, the diameter of the shield 30 may be at least 15 mm, such as approximately 20 mm.

[0070] like Figure 3AAs described, shielding member 30 includes multiple radiopaque markers, including radiopaque marker 42a and radiopaque marker 42b (collectively referred to as "radiopaque marker 42"). Shielding member 30 may include any number of radiopaque markers or none. Radiopaque markers 42 may be distributed symmetrically on shielding member 30, for example, relative to pacing / sensing electrode 32b. Radiopaque markers 42 may be positioned on shielding member 30 to allow a user to visualize at least one of the location or orientation of the shielding member within the patient's body by recognizing the radiopaque markers in fluoroscopy or other images. Radiopaque markers 42 may differ from each other in one or more ways, such as size, shape, or orientation, to allow, for example, a physician to distinguish radiopaque markers 42, thereby facilitating visualization of the orientation of shielding member 30. For example, one of the radiopaque markers 42 positioned on shielding member 30 may be larger than the others, allowing a physician to determine the orientation of shielding member 30 based on the position of the larger radiopaque marker (e.g., relative to the others of radiopaque marker 42).

[0071] like Figure 3A and 3B As described herein, the distal portion 16 of lead 10 may include lead body portion 40a and lead body portion 40b (collectively referred to as "lead body portion 40"). Lead body portion 40 extends between a corresponding one of pacing / sensing electrode 32b and defibrillation electrode 28. Lead body portion 40 may provide a relatively flat or smooth surface transition between the outer contour of pacing / sensing electrode 32b and the outer contour of defibrillation electrode 28. Conductors coupled to electrodes 32b and 28b may extend through lead body portion 40a, and conductors coupled to electrode 28b may extend through lead body portion 40b. Lead body portions 40a and 40b may be formed of one or more polymers and may be the same as or different from other portions of shield 30 and / or lead body 13.

[0072] like Figure 3C As described, the pacing / sensing electrode 32b may define a cavity 53, for example, it may be annular, and a conductor coupled to the electrode 28b may extend through the cavity 53. Although in Figure 3C The description is circular, but the pacing / sensing electrode 32 may have other shapes, including partial or segmented circular or arc-shaped, wherein one or more electrodes or electrode segments extend less than 360 degrees around the circumference of the lead.

[0073] Since the shield 30 only covers the forward portion of the outer surface 43 of the pacing / sensing electrode 32b, the depth 49 of the shield 30 can be less than the depth 51 of the pacing / sensing electrode 32b, such as less than half the depth of the electrode. Although described as substantially constant, the depth 49 of the shield 30 can vary. For example, the depth 49 can increase towards the pacing / sensing electrode 32b and / or decrease towards the edge of the shield, for example, to provide a smooth or otherwise desired transition between the shield 30 and the pacing / sensing electrode 32b and / or between the shield 30 and the patient's tissue. Furthermore, although the defibrillator electrode 28, the pacing / sensing electrode 32b, and the lead body portions 40a and 40b are in... Figure 3B The diagram shows a substantially equal depth (e.g., circumference) to the depth 49 of the shield 30, but in other instances, the depth 49 of the shield 30 may be similar to the depth of the lead body portions 40a and 40b, and the pacing / sensing electrode 32b may extend outward from the lead body portions 40a and 40b and the shield 30, for example, due to having a greater depth or offset from the longitudinal axis defined by the lead body portions 40a and 40b.

[0074] like Figure 3C As described, the pacing pulse delivered by the ICD 9 via the pacing / sensing electrode 32b generates an electric field 55 near the electrode, which "diffuses" from the outer surface 43 of the electrode. The shield 30 reduces and / or blocks the electric field in the direction from the electrode toward the shield, and allows diffusion in the direction from the electrode away from the shield. In this way, the shield 30 is configured to give the pacing / sensing electrode 32b directionality.

[0075] Figure 4 A flowchart illustrating an example technique for implanting an implantable medical lead, including a shielding element. Figure 4 This is described in relation to the implantable medical lead 10 and the shielding element 30. However, Figure 4 The technique can be used to implant other leads that contain one or more shielding elements.

[0076] Medical practitioners can use implantation tools to implant the distal portion 16 of the implantable medical lead 10 under the sternum or in other extravascular locations. In some instances, such as by... Figure 4As illustrated, a medical practitioner or assistant may fold or wrap the shield 30 around the pacing / sensing electrode 32b so that it can be installed within the cavity (or channel) of the implantation tool, and introduce the distal portion 16 of the lead 10 into the cavity (50). In some instances, the distal portion 16 may be loaded into the cavity and packaged in sterile packaging, for example, by the manufacturer of the lead 10 and / or the implantation tool prior to the implantation procedure. The cavity of the implantation tool may be cylindrical, or may otherwise have a profile that matches the outer contour of the distal portion 16. The wavy configuration of the distal portion 16 may be straightened within the cavity. In one instance, the cavity may include a sheath. This disclosure contemplates configurations other than those of the cavity of the implantation tool that include the shield 30 for release.

[0077] In some instances, a medical practitioner may introduce the implantable tool into the patient via a subxiphoid incision and advance the tool to an extravascular location. Advancement to the extravascular location may occur before or after the lead 10 is loaded onto the tool. In either case, the distal portion 16 of the lead 10 is positioned at the extravascular location (52) using the implantable tool, for example, by advancing it through a lumen or while it is in a lumen. In one embodiment, the implantable tool may comprise a tunneling tool having a rod or other tunneling member and a sheath configured to rest on the rod.

[0078] according to Figure 4 In one example, a medical practitioner removes the distal portion 16 of the lead 10 from the implantation tool to release the shield (54). In the case of an implantation tool comprising a sheath with a cavity, the medical practitioner can release the shield by withdrawing the sheath proximally from the patient and / or by tearing the sheath. In other embodiments, the implantation tool or the sheath of the implantation tool may be formed with a channel or other recess accessible via a longitudinal opening to receive the distal portion 16 of the lead 10 containing the shield 30, and the medical practitioner can release the shield by laterally separating the distal portion 16 of the lead 10 from the channel or other recess of the sheath or implantation tool. When the shield 30 does not have a cavity, the shield 30 may transition from a folded or wrapped configuration to an unfolded configuration, for example, it may be elastically deformable to a folded or wrapped configuration and released to an unfolded configuration, which may be a relaxed configuration. In some instances, the lead 10 may include a fluid, a balloon, a spring, or other actuable mechanism to transition the shield 30 to the unfolded configuration.

[0079] Medical practitioners may use, for example, fluoroscopy or other medical imaging to visualize the shield 30 inside the patient to identify radiopaque markings (56). If necessary, the medical practitioner may rotatably orient the distal portion 16 of the lead 10 such that the shield 30 is positioned forward relative to the pacing / sensing electrode 32b (58).

[0080] Figure 5A flowchart illustrating an example technique for manufacturing implantable medical leads, including shielding components. Figure 5 This is described in relation to the implantable medical lead 10 and the shielding element 30. However, Figure 5 The technique can be used to implant other leads that contain one or more shielding elements.

[0081] according to Figure 5 In some embodiments, the shield 30 is attached to the forward portion (60) of the surface 43 of the pacing / sensing electrode 32b. In some embodiments, the shield 30 is a separately molded element that is attached to the pacing / sensing electrode 32b using an adhesive. In other embodiments, the shield 30 is molded onto the pacing / sensing electrode 32b. In some embodiments, molding the shield 30 onto the pacing / sensing electrode 32b further includes molding the lead body portion 40a to the proximal end of the pacing / sensing electrode 32b and molding the lead body portion 40b to the distal end of the pacing / sensing electrode 32b; for example, the shield 30 and the lead body portion 40 can be molded as a single piece of common material. The pacing / sensing electrode 32b and the shield 30 (and in some cases the lead body portion 40) can then be assembled as a unit onto the lead 10 (62). The lead 10 can then optionally be overmolded (64).

[0082] Figure 6 This is a conceptual diagram illustrating the distal portion 116 of an example implantable medical lead that includes multiple shielding elements. The distal portion 116 is similar to the distal portion 16 of lead 10, and the same numbered elements in the distal portion 116 are similar to those in the distal portion 16. For example, the distal portion 116 includes defibrillation electrodes 128a and 128b and pacing / sensing electrodes 132a and 132b, and defines a wave-like configuration similar to that of the distal portion 16.

[0083] like Figure 6 As illustrated, the distal portion 116 includes a first shield 130a over the forward portion of the surface of the pacing / sensing electrode 132a and a second shield 130b over the forward portion of the surface of the pacing / sensing electrode 132b. Shields 130a and 130b may be the same as or different from each other. In some instances, each of shields 130a and 130b may be the same as or substantially similar to shield 30 as described herein with respect to Figures 1-5, for example, it may include any combination of one or more of the features described above with respect to shield 30.

[0084] Figure 7This is a conceptual diagram illustrating the distal portion 216 of another example of an implantable medical lead, which includes multiple shielding elements. The distal portion 216 is similar to the distal portion 16 of lead 10, and the same numbered elements in the distal portion 216 are similar to those in the distal portion 16. For example, the distal portion 216 includes defibrillation electrodes 228a and 228b and pacing / sensing electrodes 232a and 232b, and defines a wave-like configuration similar to that of the distal portion 16.

[0085] like Figure 7 As illustrated, the distal portion 216 includes a plurality of shielding elements, including shielding elements 230a and 230b (collectively referred to as “shielding elements 230”). Shielding elements 230 may be the same as or different from each other. In some instances, each of the shielding elements 230 may be the same as or substantially similar to the shielding element 30 described herein with respect to Figures 1-5, for example, it may include any combination of one or more of the features described above with respect to shielding element 30.

[0086] like Figure 7 As illustrated, shielding 230 may collectively cover the forward portion of the outer surface of each of electrodes 228 and 232. In some instances, defibrillator electrode 228 may be used to deliver pacing pulses, and shielding 230 may provide the same directionality of the electric field near defibrillator electrode 228 as described with respect to pacing sensing electrode 232. (Using as...) Figure 7 The multiple shields 230 arranged as described herein can provide the directionality of the electric field, while allowing the distal portion 216 to be straightened for implantation and then to take the illustrated wavy configuration during implantation.

[0087] Figure 8 This is a conceptual diagram illustrating another example of an implantable medical lead, the distal portion 316, including a shield. Elements of the same number in the distal portion 316 are similar to those in the distal portion 16. For example, the distal portion 316 includes defibrillation electrodes 328a and 328b, and pacing / sensing electrodes 332a and 332b. However, unlike the distal portion 16, the distal portion 316 is defined in a straight or substantially straight configuration, rather than a wavy configuration. Figure 8 As illustrated, the distal portion 316 includes a single shield 330 that covers the forward portion of the outer surface of each of electrodes 228 and 232. Shield 330 may be the same as or substantially similar to shield 30 described herein with respect to Figures 1-5, for example, it may include any combination of one or more of the features described above with respect to shield 30.

[0088] Although the distal portion of the example implantable medical leads described herein typically includes two defibrillation electrodes and two pacing / sensing electrodes, with one pacing / sensing electrode located between the defibrillation electrodes and the other proximal to the defibrillation electrode, any shielding described herein may be included as part of implantable medical leads with different configurations. For example, some implantable medical leads may include a single defibrillation electrode and one or more pacing / sensing electrodes located distal to and / or proximal to the defibrillation electrode. In other instances, implantable medical leads containing one or more stimulating electrodes that are not necessarily used for cardiac pacing do not include a defibrillation electrode. In any such instance, one or more shielding elements configured as described herein may be located above a portion of the surface of one or more electrodes.

[0089] Figure 9 This is a conceptual diagram illustrating a portion of the distal portion 516 of another implantable medical lead, including a shield. The distal portion 516 may resemble the distal portion 16 of lead 10, and elements of the same number in the distal portion 516 may resemble those in the distal portion 16. For example, the distal portion 516 includes defibrillation electrodes 528a and 528b (collectively referred to as “defibrillation electrodes 528”) and a pacing / sensing electrode 532.

[0090] The distal portion 516 also includes a lead body portion 540 extending from defibrillator electrode 528a to defibrillator electrode 528b. The lead body portion 540 may provide a relatively flat or smooth surface transition between the outer contours of the defibrillator electrodes 528. The lead body portion 540 may be formed of an insulating material, and conductors coupled to electrodes 532 and 528b may extend through the lead body portion 540.

[0091] In the Figure 9 In the illustrated example, the pacing / sensing electrode 532 is located within a recessed portion 570 of the lead body portion 540. The lead body portion 540 with the recessed portion 570 covers the forward portion of the surface of the pacing / sensing electrode 532 and blocks the electric field, at least in the forward direction. Although in Figure 9 Not shown, but the distal portion 516 may additionally include a shield 30 or any other shield as described herein above the forward portion of the surface of the pacing / sensing electrode 532 to block the electric field in the forward direction.

[0092] Figure 10This is a functional block diagram configuring examples of the electronic components and other components of the ICD 9. The ICD 9 includes a processing circuitry 402, a sensing circuitry 404, a therapeutic delivery circuitry 406, a sensor 408, a communication circuitry 410, and a memory 412. In other examples, the ICD 9 may contain more or fewer components. The described circuitry and other components may be implemented together on shared hardware components or separately as discrete but interoperable hardware or software components. The depiction of different features is intended to highlight different functional aspects and does not necessarily imply that such circuitry and other components must be implemented by separate hardware or software components. Rather, the functionality associated with one or more modules or circuitry and components may be performed by separate hardware or software components or integrated within shared or separate hardware or software components.

[0093] Sensing circuitry 404 may be electrically coupled to some or all of the electrodes 416, which may correspond to any of the defibrillation, pacing / sensing, and shell electrodes described herein. Sensing circuitry 404 is configured to acquire and process signals sensed via one or more combinations of electrodes 416.

[0094] The components of the sensing circuit system 404 can be analog components, digital components, or a combination thereof. The sensing circuit system 404 may, for example, include one or more sensing amplifiers, filters, rectifiers, threshold detectors, analog-to-digital converters (ADCs), etc. The sensing circuit system 404 can convert the sensed signal into digital form and provide the digital signal to the processing circuit system 402 for processing or analysis. For example, the sensing circuit system 404 can amplify the signal from the sensing electrode and convert the amplified signal into a multi-bit digital signal via an ADC. The sensing circuit system 404 can also compare the processed signal with a threshold to detect the presence of atrial or ventricular depolarization (e.g., P wave or R wave) and indicate the presence of atrial depolarization (e.g., P wave) or ventricular depolarization (e.g., R wave) to the processing circuit system 402. Figure 10 As shown, the ICD 9 may additionally include one or more sensors 408, such as one or more accelerometers, which may be configured to provide signals to the processing circuitry system 402 indicating other parameters of the patient, such as activity or posture.

[0095] The processing circuitry system 402 can process signals from the sensing circuitry system 404 to monitor the electrical activity of the heart 26 of the patient 12. The processing circuitry system 402 can store the signals obtained through the sensing circuitry system 404, along with any generated EGM waveforms, marker channel data, or other data derived based on the sensed signals, in memory 412. The processing circuitry system 402 can analyze the EGM waveforms and / or marker channel data to detect arrhythmias (e.g., bradycardia or tachycardia). In response to the detection of a cardiac event, the processing circuitry system 402 can control the treatment delivery circuitry system 406 to deliver the desired treatment to treat the cardiac event, such as a defibrillation shock, cardioversion shock, ATP, post-shock pacing, or bradycardia pacing.

[0096] Therapeutic delivery circuitry 406 is configured to generate electrical therapy and deliver it to the heart 26. Therapeutic delivery circuitry 406 may include one or more pulse generators, capacitors, and / or other components capable of generating and / or storing energy for delivery as pacing therapy, defibrillation therapy, cardioversion therapy, cardiac resynchronization therapy, other therapy, or combinations thereof. In some cases, therapeutic delivery circuitry 406 may include a first set of components configured to provide pacing therapy and a second set of components configured to provide defibrillation therapy. In other cases, therapeutic delivery circuitry 406 may utilize the same set of components to provide both pacing and defibrillation therapy. In still other cases, therapeutic delivery circuitry 406 may share some of the defibrillation and pacing therapy components while using other components only for defibrillation or pacing. Processing circuitry 402 may control therapeutic delivery circuitry 406 to deliver the generated therapy to the heart 26 via one or more combinations of electrodes 416. Although Figure 10 Not shown, but the ICD 9 may include a switching circuit system that can be configured by the processing circuit system 402 to control which of the electrodes 416 are connected to the treatment delivery circuit system 406 and the sensing circuit system 404.

[0097] The communication circuitry system 410 includes any suitable hardware, firmware, software, or any combination thereof for communicating with another device, such as a clinician programmer, a patient monitoring device, etc. For example, the communication circuitry system 410 may include suitable modulation, demodulation, frequency conversion, filtering, and amplifier components for transmitting and receiving data via an antenna.

[0098] The various components of the ICD 9 may include any one or more processors, controllers, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or equivalent discrete or integrated circuit systems, including analog circuit systems, digital circuit systems, or logic circuit systems. Processing circuit system 402 may include fixed-function circuit systems and / or programmable processing circuit systems. The functions attributed to processing circuit system 402 herein may be embodied in software, firmware, hardware, or any combination thereof.

[0099] Memory 412 may contain computer-readable instructions that, when executed by processing circuitry system 402 or other components of ICD 9, cause one or more components of ICD 9 to perform various functions belonging to those components of this disclosure. Memory 412 may contain any volatile, non-volatile, magnetic, optical, or electrical medium, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), static non-volatile RAM (SRAM), electrically erasable programmable ROM (EEPROM), flash memory, or any other non-volatile computer-readable storage medium.

[0100] The lead and system described herein can be used at least partially within the substernal space, for example, in the anterior mediastinum of a patient, to deliver an extravascular ICD system. The implanter (e.g., a physician) can use any of a variety of implantation tools, such as a tunneling rod, a sheath, or other tools that can pass through a diagrammatic attachment and form a tunnel in the substernal location, to implant the distal portion of the lead into the thoracic cavity. For example, the implanter may make an incision near the center of the patient's trunk, for example, and introduce the implantation tool into the substernal location through the incision. The implantation tool is advanced upwards along the posterior sternum from the incision in the substernal location. The distal portion of the lead is introduced into the tunnel via the implantation tool (e.g., via the sheath). The distal portion is relatively straight as it is advanced through the substernal tunnel. A pre-formed or shaped wavy configuration is sufficiently flexible to be straightened as the lead is guided through the sheath or other cavities or channels of the implantation tool. Once the distal portion is in place, the implantation tool is withdrawn toward the incision and removed from the patient's body, leaving the lead in place along the substernal path. When the implantation tool is withdrawn, the distal end of the lead exhibits its pre-formed wavy configuration, and the shield transitions to its unfolded configuration.

[0101] In some instances, the distal portion of the lead may be orthogonal to or otherwise transverse to the sternum and / or below the heart orientation, rather than extending upward along the sternum. In such instances, according to any of the examples described herein, the lead may include one or more shielding elements that cover a portion of the outer surface of one or more electrodes, such as forward and / or downward portions. One or more such shielding elements may block the electric field in a direction away from the heart, which may be forward and / or downward.

[0102] In this way, the following terms can be achieved in various aspects of the technology.

[0103] Clause 1: An implantable medical lead comprising: a first defibrillator electrode and a second defibrillator electrode configured to deliver an anti-tachyarrhythmic shock; a pacing electrode disposed between the first defibrillator electrode and the second defibrillator electrode, the pacing electrode being configured to deliver a pacing pulse that generates an electric field in the vicinity of the pacing electrode; and a shield disposed between the first defibrillator electrode and the second defibrillator electrode, above a portion of the outer surface of the pacing electrode and extending laterally away from the pacing electrode, wherein the shield is configured to block the electric field in the direction from the pacing electrode to the heart.

[0104] Clause 2: The implantable medical lead as described in Clause 1, wherein the length of the shield is greater than the length of the pacing electrode.

[0105] Clause 3: The implantable medical lead as described in Clause 2, wherein the length of the shield is at least twice the length of the pacing electrode.

[0106] Clause 4: An implantable medical lead according to any one of Clauses 1 to 3, wherein the shielding extends from the distal end of the proximal electrode of the first defibrillator and the second defibrillator to the proximal end of the distal electrode of the first defibrillator and the second defibrillator.

[0107] Clause 5: An implantable medical lead according to any one of Clauses 1 to 4, wherein the width of the shield is greater than the width of the pacing electrode.

[0108] Clause 6: The implantable medical lead as described in Clause 5, wherein the width of the shield is at least twice the width of the pacing electrode.

[0109] Clause 7: An implantable medical lead according to any one of Clauses 1 to 6, wherein the shield extends at least 5 mm beyond the pacing electrode in each direction orthogonal to the longitudinal axis of the pacing electrode.

[0110] Clause 8: An implantable medical lead according to any one of Clauses 1 to 7, wherein the shield is symmetrical about the longitudinal axis of the pacing electrode.

[0111] Clause 9: An implantable medical lead according to any one of Clauses 1 to 8, wherein the diameter of the shield is greater than 15 mm.

[0112] Clause 10: The implantable medical lead as described in Clause 9, wherein the diameter of the shield is approximately 20 mm.

[0113] Clause 11: An implantable medical lead according to any one of Clauses 1 to 10, wherein the shielding is electrically insulated.

[0114] Clause 12: An implantable medical lead according to any one of Clauses 1 to 11, wherein the shielding comprises a polymer.

[0115] Clause 13: An implantable medical lead according to any one of Clauses 1 to 12, wherein the shielding comprises polyurethane.

[0116] Clause 14: An implantable medical lead according to any one of Clauses 1 to 13, wherein the shield is configured to be folded or wrapped around the pacing electrode for delivery via a cavity of the implantation tool, and is configured to resiliently defold or unfold into an open configuration upon release from the cavity.

[0117] Clause 15: An implantable medical lead according to any one of Clauses 1 to 14, wherein the shielding includes at least one radiopaque marker spaced laterally from the pacing electrode.

[0118] Clause 16: The implantable medical lead as described in Clause 15, wherein the shielding comprises a plurality of radiopaque markers symmetrically distributed relative to the pacing electrode.

[0119] Clause 17: An implantable medical lead according to any one of Clauses 1 to 16, wherein the distal portion of the implantable medical lead defines a wave configuration comprising a first peak extending in a first direction, a second peak extending in the first direction, and a third peak extending in a second direction opposite to the first direction between the first peak and the second peak, and wherein at least a portion of a first defibrillator electrode is disposed on the first peak, at least a portion of a second defibrillator electrode is disposed on the second peak, and at least a portion of a pacing electrode is disposed on the third peak.

[0120] Clause 18: Implantable medical leads as described in Clause 17, wherein the wavy configuration defines a basic sinusoidal configuration.

[0121] Clause 19: An implantable medical lead according to any one of Clauses 1 to 18, wherein the shielding is planar.

[0122] Clause 20: An implantable medical lead according to any one of Clauses 1 to 18, wherein the shielding is non-planar.

[0123] Clause 21: The implantable medical lead as described in Clause 20, wherein a portion of the shield that is more posteriorly spaced away from the pacing electrode is positioned further back than a portion closer to the pacing electrode.

[0124] Clause 22: An implantable medical lead according to any one of Clauses 1 to 21, wherein the shielding includes at least one support structure configured to facilitate at least one of deployment or hinge of the shielding.

[0125] Clause 23: Implantable medical leads as described in Clause 22, wherein the support structure comprises nitinol.

[0126] Clause 24: An implantable medical lead as described in Clause 22 or 23, wherein the support structure is located on the periphery of the shield.

[0127] Clause 25: An implantable medical lead according to any one of Clauses 1 to 24, further comprising a lead body portion having a groove, wherein the pacing electrode is recessed within the groove of the lead body portion.

[0128] Clause 26: An implantable medical lead according to any one of Clauses 1 to 25, wherein the pacing electrode comprises a first pacing electrode and the shield comprises a first shield, the implantable medical lead comprises a second pacing electrode; and a second shield disposed above a portion of the outer surface of the second pacing electrode and extending laterally away from the second pacing electrode, wherein the second shield is configured to block the electric field in the direction from the second pacing electrode away from the heart.

[0129] Clause 27: An implantable medical lead according to any one of Clauses 1 to 26, further comprising a plurality of shields distributed along the length of the distal portion of the implantable medical lead.

[0130] Clause 28: An implantable medical lead according to any one of Clauses 1 to 27, wherein the portion of the surface of the pacing electrode is a forward portion, and the shield is configured to block the electric field in the forward direction from the pacing electrode.

[0131] Clause 29: An implantable medical lead according to any one of Clauses 1 to 27, wherein the portion of the surface of the pacing electrode is a downward portion, and the shield is configured to block the electric field in the downward direction from the pacing electrode.

[0132] Clause 30: An implantable cardioverter defibrillator (ICD) system comprising an implantable medical lead according to any one of Clauses 1 to 29; and an ICD configured to generate pacing pulses.

[0133] Clause 31: A method of manufacturing an implantable medical lead according to any one of Clauses 1 to 29, comprising positioning the distal portion of the implantable medical lead at a location within a patient's body; and rotatably orienting the distal portion of the implantable medical lead such that the shield is opposite the pacing electrode to the heart.

[0134] Clause 32: The method according to Clause 31 further includes visually identifying a plurality of radiopaque markers of the shield to visualize at least one of the location or orientation of the shield within the patient's body.

[0135] Clause 33: The method described in Clause 31 or 32 further comprises removing the implantable medical lead from the cavity of the implantation tool to release the shield from a wound or folded configuration to an open configuration.

[0136] Clause 34: The method according to any one of Clauses 31 to 33, wherein rotatably orienting the distal portion comprises rotatably orienting the distal portion such that the shield is positioned forward relative to the pacing electrode.

[0137] Clause 35: The method according to any one of Clauses 31 to 33, wherein rotatably orienting the distal portion comprises rotatably orienting the distal portion such that the shield is positioned downward relative to the pacing electrode.

[0138] Clause 36: A method of manufacturing an implantable medical lead according to any one of Clauses 1 to 29, comprising attaching a shield to the surface of a pacing electrode; and subsequently assembling the shield and the pacing electrode into the implantable medical lead.

[0139] Clause 37: The method according to Clause 36, wherein attaching the shield to the surface of the pacing electrode comprises molding the shield onto the pacing electrode.

[0140] Clause 38: The method according to Clause 37, wherein molding the shield onto the pacing electrode further comprises molding a first lead body portion onto the distal end of the pacing electrode and molding a second lead body portion onto the proximal end of the pacing electrode.

[0141] Those skilled in the art will understand that this application is not limited to the content specifically shown and described above. Furthermore, unless otherwise stated above, it should be noted that all figures are not drawn to scale.

Claims

1. An implantable medical lead, comprising: First defibrillation electrode and second defibrillation electrode, the first and second defibrillation electrodes being configured to deliver an anti-tachyarrhythmic shock; A pacing electrode is disposed between a first defibrillation electrode and a second defibrillation electrode, the pacing electrode being configured to deliver a pacing pulse that generates an electric field in the vicinity of the pacing electrode; and Shielding components The shielding element is disposed above a portion of the outer surface of the pacing electrode. When deployed, the shield extends laterally away from the pacing electrode. The shielding element is configured to, in the deployed configuration, block the electric field in the direction from the pacing electrode away from the heart. The shielding element is disposed between the first defibrillation electrode and the second defibrillation electrode. The shielding component mentioned above: Extending above only a portion of the first defibrillator electrode, wherein this portion of the first defibrillator electrode includes the end of the first defibrillator electrode closest to the pacing electrode, and Extending above only a portion of the second defibrillator, which includes the end of the second defibrillator closest to the pacing electrode.

2. The implantable medical lead according to claim 1, wherein the length of the shield is greater than the length of the pacing electrode.

3. The implantable medical lead according to claim 1 or 2, wherein the shielding extends from the distal end of the proximal electrode of the first defibrillator and the second defibrillator to the proximal end of the distal electrode of the first defibrillator and the second defibrillator.

4. The implantable medical lead according to claim 1 or 2, wherein the width of the shield is greater than the width of the pacing electrode.

5. The implantable medical lead according to claim 1 or 2, wherein the shielding is electrically insulating.

6. The implantable medical lead of claim 1 or 2, wherein the shield is configured to fold or wrap around the pacing electrode for delivery via a cavity of the implantation tool, and is configured to resiliently defold or unfold to an open configuration upon release from the cavity.

7. The implantable medical lead according to claim 1 or 2, The distal portion of the implantable medical lead defines a wavy configuration comprising a first peak extending in a first direction, a second peak extending in the first direction, and a third peak extending between the first and second peaks in a second direction opposite to the first direction. At least a portion of the first defibrillator electrode is disposed on the first peak, at least a portion of the second defibrillator electrode is disposed on the second peak, and at least a portion of the pacing electrode is disposed on the third peak.

8. The implantable medical lead according to claim 1 or 2, wherein the shielding includes at least one support structure configured to facilitate at least one of deployment or hinge of the shielding.

9. The implantable medical lead of claim 8, wherein the support structure comprises nitinol.

10. The implantable medical lead according to claim 1 or 2, further comprising a lead body portion including a groove, wherein the pacing electrode is recessed within the groove of the lead body portion.

11. The implantable medical lead according to claim 1 or 2, wherein the pacing electrode includes a first pacing electrode, and the shielding member includes a first shielding member, the implantable medical lead comprising: Second pacing electrode; and A second shield is disposed above a portion of the outer surface of the second pacing electrode and extends laterally away from the second pacing electrode, wherein the second shield is configured to block the electric field in the direction from the second pacing electrode away from the heart.

12. The implantable medical lead according to claim 1 or 2, further comprising a plurality of shielding elements distributed along the length of the distal portion of the implantable medical lead.

13. The implantable medical lead of claim 1 or 2, wherein the portion of the surface of the pacing electrode is a downward portion, and the shield is configured to block the electric field in the downward direction from the pacing electrode.

14. An implantable medical system comprising: Implantable medical devices, including: The outer shell; and A therapeutic delivery circuitry system, located within the housing and configured to generate anti-tachyarrhythmic shocks and pacing pulses; and The implantable medical lead according to any one of claims 1 to 13.

15. A method for manufacturing an implantable medical lead according to any one of claims 1 to 14, the method comprising: A shield is attached to the surface of a pacing electrode, wherein the pacing electrode is configured to deliver a pacing pulse that generates an electric field in the vicinity of the pacing electrode, and wherein the shield is configured to block the electric field in the direction away from the pacing electrode. and The shield and the pacing electrode are then assembled onto the implantable medical lead comprising a first defibrillator electrode and a second defibrillator electrode, wherein the first and second defibrillator electrodes are configured to deliver anti-tachyarrhythmic shocks, wherein the pacing electrode is assembled such that it is disposed between the first and second defibrillator electrodes, wherein the shield is assembled such that it is disposed between the first and second defibrillator electrodes, above a portion of the outer surface of the pacing electrode and extending laterally away from the pacing electrode, and wherein the shield is configured to block the electric field in the direction from the pacing electrode away from the heart.

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