Systems and methods for treating cardiac arrhythmias

Abstract

A leadless pacing device may include a housing having a proximal end and a distal end, and one or more electrodes supported by the housing. The housing may include a body portion and a head portion. A distal extension may extend distally from the head portion of the housing, the distal extension portion including one or more electrodes. The head portion may include a guidewire port, and a guidewire lumen may extend from the guidewire port through the head portion of the housing and through the distal extension portion. A fixing member may extend from the head portion of the housing, wherein the fixing member has a helical configuration in a relaxed state and is configured to plastically deform into a straightened configuration in response to an axial withdrawal force applied thereto.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority under 35 U.S.C. §119 to U.S. Provisional Application No. 62 / 826,507, filed on March 29, 2019, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] The present disclosure relates to medical devices and methods for making and / or using medical devices. More specifically, the present disclosure relates to leadless cardiac devices and methods, such as leadless pacing devices and methods, and delivery devices and methods for such leadless devices. Background Art

[0004] A wide variety of medical devices have been developed for medical uses, such as cardiac uses. Some of these devices include catheters, leads, pacemakers and the like, as well as delivery devices and / or systems for delivering such devices. These devices can be manufactured by any of a variety of different manufacturing methods and can be used according to any of a variety of methods. Of the known medical devices, delivery systems and methods, each has certain advantages and disadvantages. There is a continuing need to provide alternative medical devices and delivery devices and alternative methods for making and using medical devices and delivery devices. Summary of the invention

[0005] The present disclosure provides alternatives for the design, materials, manufacturing methods, and uses of medical devices, including cardiac sensing and pacing devices and delivery devices.

[0006] The first example is a leadless pacing device for delivering electrical stimulation to a patient's heart. The leadless pacing device includes a housing having a central longitudinal axis. The housing includes a body portion and a head extending distally from the body portion. A fixation member extends from the head portion. A distal extension is connected to the head portion and extends distally of a distal end of the head portion. The fixation member has a helical configuration in a relaxed state and is configured to elongate to a straight configuration in response to an axial force applied thereto.

[0007] Alternatively or additionally to any of the above examples, the fixation member is configured to extend to the straightened configuration in response to an axial force applied thereto in the range of 0.1 lbf to 1.0 lbf.

[0008] Alternatively or additionally to any of the above examples, the fixation member plastically deforms to the straightened configuration in response to the axial force.

[0009] Alternatively or additionally to any of the above examples, the fixing member is formed of a platinum-iridium material.

[0010] Alternatively or additionally to any of the above examples, the securing member extends at least partially around an exterior surface of the head.

[0011] Alternatively or additionally to any of the above examples, the leadless pacing device includes a drug ring positioned at least partially around the head.

[0012] Alternatively or additionally to any of the above examples, the drug collar is at least partially positioned between the securing member and an exterior surface of the head.

[0013] Alternatively or additionally to any of the above examples, the drug collar is secured to the head by one or both of a medical grade adhesive and an interface comprising polyetheretherketone.

[0014] Alternatively or additionally to any of the above examples, the head extends distally of a distal tip of the fixation member.

[0015] Alternatively or additionally to any of the above examples, the fixation member comprises a helical anchor extending to the distal tip.

[0016] Alternatively or additionally to any of the above examples, the fixation member includes: a proximal portion embedded in the proximal portion of the head; a helical coil portion surrounding an outer surface of the distal portion of the head and spaced radially outward from the outer surface; and a distal tip forming a terminal end of the fixation member. The distal tip is positioned proximal to the distal end of the head.

[0017] Another example is a method of removing a leadless pacing device from a coronary sinus of a patient's heart. The method includes advancing a positioning device through the patient's vasculature to a leadless pacing device, the leadless pacing device being at least partially positioned in the patient's coronary sinus. The positioning device then engages the leadless pacing device and applies a force to the leadless pacing device via the positioning device to remove a helical fixation anchor of the leadless pacing device from tissue surrounding the coronary sinus. The leadless pacing device and positioning device are then withdrawn from the patient's coronary sinus and vasculature.

[0018] Alternatively or additionally to any of the above examples, the applied force is a rotational force.

[0019] Alternatively or additionally to any of the above examples, the applied force is a longitudinal force.

[0020] Alternatively or additionally to any of the above examples, the helical fixation anchor is plastically deformed into a straightened configuration.

[0021] Another example is a method for positioning a leadless pacing device in the coronary sinus of a patient's heart. The method includes advancing a guide wire into the patient's coronary sinus and then advancing the leadless pacing device over the advanced guide wire. The leadless pacing device includes a housing. The housing has a body portion and a head extending distally from the body portion. The leadless pacing device also includes a fixation member extending from the head that is configured to engage tissue near the patient's coronary sinus. The leadless pacing device is rotated in the coronary sinus to engage the fixation member with tissue near the patient's coronary sinus and secure the leadless pacing device against a wall of the coronary sinus that forms a wall of a chamber of the patient's heart.

[0022] Alternatively or additionally to any of the above examples, the leadless pacing device is advanced over the advanced guidewire while positioned within a lumen of a delivery sheath. The method further includes rotating the housing while the leadless pacing device is positioned in the coronary sinus and within the lumen of the delivery sheath until a terminal end of the fixation member faces a wall of the coronary sinus, the wall of the coronary sinus forming a wall of a chamber of the patient's heart.

[0023] Alternatively or additionally to any of the above examples, advancing the fixation member when the terminal end of the fixation member faces a wall of the coronary sinus forming a wall of a patient's heart chamber will advance the fixation member distally out of the lumen of the delivery sheath.

[0024] Alternatively or additionally to any of the above examples, the rotating step causes tissue to be positioned between the fixation member and the head.

[0025] Alternatively or additionally to any of the above examples, the fixation member is penetrated into the left atrial muscle of the patient's heart.

[0026] The above summary of some embodiments is not intended to describe each disclosed embodiment or every implementation of the present disclosure. The following figures and detailed description more particularly illustrate some of these embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present disclosure may be more fully understood when the following detailed description is considered in conjunction with the accompanying drawings, in which:

[0028] Figure 1 is a schematic diagram of an example leadless pacing device implanted in the heart;

[0029] Figure 2 is a side view of an exemplary implantable leadless pacing device;

[0030] Figure 3 is a schematic block diagram of an exemplary implantable leadless pacing device;

[0031] Figure 4 It is along Figure 3 A schematic cross-sectional view taken along line 4-4 in FIG.

[0032] Figure 5 is a cross-sectional side view of a distal portion of an exemplary implantable leadless pacing device;

[0033] Figure 6 is a cross-sectional side view of a distal portion of an exemplary implantable leadless pacing device having a strain relief feature;

[0034] Figure 7-13 is a view of an example helical coil for a securing member, the helical coil having an exposed conductive surface;

[0035] Fig.14 is a schematic diagram of an exemplary implantable leadless pacing device in a heart;

[0036] Figures 15A-15B is a schematic diagram of an exemplary implantable leadless pacing device in a heart;

[0037] Fig.16 is a side view of a distal end portion of an exemplary implantable leadless pacing device having a communication line;

[0038] Fig.17 is a side view of a distal end portion of an exemplary implantable leadless pacing device having a communication line at a strain relief feature;

[0039] Fig.18 is a perspective view of a distal end portion of an exemplary implantable leadless pacing device having a drug collar;

[0040] Fig.19 is a side view of a distal end portion of an exemplary implantable leadless pacing device having a drug collar;

[0041] Fig. 20 is a side view of a distal end portion of an exemplary implantable leadless pacing device having a drug collar;

[0042] Fig.21 is a side view of a distal end portion of an exemplary implantable leadless pacing device having a drug loop at a strain relief feature;

[0043] Fig. 22 is a side view of an exemplary implantable leadless pacing device having a housing with a two-part second portion; and

[0044] Figure 23-31 is a series of schematic diagrams illustrating delivery of an exemplary implantable leadless pacing device into and removal from a patient's heart.

[0045] Although the present disclosure is subject to various modifications and alternative forms, specific cases thereof have been illustrated in the drawings by way of example and will be described in detail. However, it should be understood that it is not intended to limit aspects of the present disclosure to the specific embodiments described. On the contrary, it is intended to cover all variations, equivalents, and alternatives that fall within the spirit and scope of the present disclosure. DETAILED DESCRIPTION

[0046] For the following defined terms, these definitions shall apply, unless a different definition is given in the claims or elsewhere in this specification.

[0047] All numerical values ​​are assumed herein to be modified by the term "about", whether or not explicitly indicated. The term "about" generally refers to a range of numbers that would be considered equivalent to the recited value (i.e., having the same function or result) by a person skilled in the art. In many cases, the term "about" may include numbers that are rounded to the nearest significant figure.

[0048] The recitation of numerical ranges by endpoints includes all numbers within that range (eg, 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

[0049] As used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally employed in its sense to include "and / or" unless the content clearly dictates otherwise.

[0050] It should be noted that references in the specification to "an embodiment", "some embodiments", "other embodiments", etc. indicate that the described embodiments may include one or more specific features, structures and / or characteristics. However, such a description does not necessarily mean that all embodiments include the specific features, structures and / or characteristics. Additionally, when specific features, structures and / or characteristics are described in connection with one embodiment, it should be understood that such features, structures and / or characteristics may also be used in connection with other embodiments, regardless of whether there is an explicit description, unless otherwise explicitly stated to the contrary.

[0051] The following detailed description should be read with reference to the drawings, in which similar structures in different drawings are numbered identically.The drawings, which are not necessarily drawn to scale, depict illustrative embodiments and are not intended to limit the scope of the disclosure.

[0052] The following description should be read with reference to the drawings, in which similar elements in different drawings are numbered identically. The description and drawings, which are not necessarily drawn to scale, illustrate illustrative embodiments and are not intended to limit the scope of the disclosure.

[0053] A cardiac pacemaker provides electrical stimulation to cardiac tissue to cause the heart to contract and thereby pump blood through the vascular system. Conventional pacemakers typically include electrical leads extending from a pulse generator implanted subcutaneously or submuscularly to electrodes positioned adjacent to the inner or outer wall of a cardiac chamber. As an alternative to conventional pacemakers, self-contained or leadless cardiac pacemakers have been proposed. Leadless cardiac pacemakers are small packages that are typically fixed to an intracardiac implantation site in or around a cardiac chamber. The small package typically includes bipolar pacing / sensing electrodes, a power source (e.g., a battery), and associated electronic circuitry (for controlling the pacing / sensing electrodes), and thereby provides electrical stimulation to cardiac tissue and / or senses a physiological condition. In some cases, a leadless cardiac pacemaker may include proximal and / or distal extensions extending from the small package, wherein the extensions may include one or more pacing / sensing electrodes. The package can be delivered to the heart using a delivery device that can be advanced through the femoral vein, into the inferior vena cava, into the right atrium, and into the coronary sinus and blood vessels extending through and / or to the coronary sinus. Accordingly, it may be desirable to provide a cardiac pacing device and a delivery device that facilitates advancement through the vasculature.

[0054] The leadless pacing devices described herein can detect and treat arrhythmias, and more specifically, deliver electrical stimulation therapy to the right atrium, left atrium, right ventricle, and / or left ventricle of a patient's heart. For example, one or more devices can be implanted on or within a patient's heart, and one or more devices can be configured to deliver electrical stimulation therapy to one or more chambers of the patient's heart and / or treat one or more types of detected arrhythmias according to one or more treatment procedures. Some example electrical stimulation therapies include bradycardia therapy, cardiac resynchronization therapy (CRT), anti-tachycardia pacing (ATP) therapy, defibrillation and / or cardioversion therapy, and the like. Some example arrhythmias include atrial fibrillation or atrial flutter, ventricular fibrillation, and tachycardia.

[0055] Although various features of the leadless pacing device are described in detail herein, alternative and / or additional features of the exemplary leadless pacing device are discussed in the following: U.S. patent application Ser. No. 15 / 924,985, filed on Mar. 19, 2018, entitled “SYSTEMS AND METHODS FOR TREATING CARDIA ARRHYTHMIAS,” which is incorporated herein by reference for all purposes; U.S. patent application Ser. No. 15 / 925,189, filed on Mar. 19, 2018, entitled “SYSTEMS AND METHODS FOR TREATING CARDIA ARRHYTHMIAS,” which is incorporated herein by reference for all purposes; U.S. patent application Ser. No. 15 / 925,146, filed on Mar. 19, 2018, entitled “SYSTEMS AND METHODS FOR TREATING CARDIA ARRHYTHMIAS,” which is incorporated herein by reference for all purposes; and U.S. patent application Ser. No. 15 / 925,194, filed on Mar. 19, 2018, entitled “SYSTEMS AND METHODS FOR TREATING CARDIA ARRHYTHMIAS,” which is incorporated herein by reference for all purposes. AND METHODS FOR TREATING CARDIAARRHYTHMIAS” which is incorporated herein by reference for all purposes. Hereinafter, these references incorporated by reference are referred to as “the incorporated references herein.”

[0056] Figure 1 is a conceptual diagram of an illustrative system for delivering electrical stimulation therapy to a patient's heart, including delivering electrical stimulation therapy to the right atrium, left atrium, right ventricle, and / or left ventricle of the patient's heart. Figure 1 An illustrative leadless pacing device 20 is shown implanted in and around the heart 10. Figure 1 The heart 10 is shown showing the right atrium 11, the left atrium 12, the right ventricle 13, the left ventricle 14, the coronary sinus 15, the coronary sinus ostium 16, the great cardiac vein 17 and the septum 18. Figure 1 In FIG. 1 , the coronary sinus 15 and the great cardiac vein 17 are shown with dashed lines because these features are on the posterior side of the heart 10 and are generally visible from the back. Figure 1 Although the leadless pacing device 20 is shown implanted and extending into the coronary sinus 15 and from Figure 115, wherein at least a portion of the leadless pacing device 20 is typically not visible in the view of the embodiment of the present invention, but for clarity, the entire leadless pacing device 20 is shown in solid lines. In some cases, about 50% of the length of the housing 22 of the leadless pacing device 20 is inserted into the coronary sinus 15, with the proximal end region of the housing 22 positioned in the right atrium 11. In some cases, about 25%-75% of the distal-most portion of the length of the housing 22 of the leadless pacing device 20 can be inserted into the coronary sinus 15, with the remaining proximal end region of the housing 22 positioned in the right atrium 11.

[0057] exist Figure 1 In an example of the leadless pacing device 20, the leadless pacing device 20 includes a housing 22 having a proximal end and a distal end and a distal extension 24 extending distally of the distal end of the housing 22. However, in some cases, the distal extension 24 may not be included and / or one or more other distal and / or proximal extensions may be included. The housing 22 can be a single part, or can have a first part 22a (e.g., a can or body), a second part 22b (e.g., a head or molded part), and / or one or more other parts. It is conceivable that the housing 22 does not have to have the same cross-sectional shape along its entire length. When implanted, the housing 22 can be completely or partially disposed within the coronary sinus 15 of the patient's heart 10, and the distal extension 24 can be completely or partially disposed within a blood vessel extending from the coronary sinus 15 (e.g., the great cardiac vein 17, the anterior interventricular vein, and / or other lateral descending vessels).

[0058] The housing 22 can have any size suitable for implantation at a target location within the patient's heart 10. In one example, the housing 22 can have a cross-sectional diameter or area sufficient to fit within the coronary sinus 15. The size of the coronary sinus 15 can vary between about 0.24 inches (6 mm) to about 0.6 inches (15 mm) in humans. In different embodiments, the diameter of the housing 22 can range from about 0.1 inches (2.54 mm) to about 0.4 inches (10 mm). These dimensions can allow the housing 22 to be implanted in coronary sinuses of different sizes while still allowing adequate blood flow through the coronary sinus 15.

[0059] The shell 22 may have one or more textures on its outer surface. In some cases, the texture of the shell 22 may include a first texture that facilitates the stability of the shell 22 at a certain position in the patient's body and a second texture that facilitates the passage of blood through the shell 22. In an example in which the shell 22 can be configured to be placed in the patient's coronary sinus 15, the first side of the shell 22 intended to be adjacent to and / or contact the excitable myocardial tissue may have a textured surface (e.g., with a rough texture) to facilitate stabilizing the shell 22 in the intended position, and the second side of the shell 22 intended to be adjacent to and / or contact the fat or pericardial tissue may have a smooth surface relative to the textured first side of the shell 22 to facilitate the passage of blood and / or other fluids through the shell 22 in the coronary sinus 15. The textured surface may be textured by sandblasting, bead blasting, sodium bicarbonate blasting, electropolishing, deposition, and / or one or more other texturing techniques. The smooth surface may be smooth from polishing, applying a protective layer or coating, and / or one or more other smoothing techniques.

[0060] In some embodiments, the leadless pacing device 20 can additionally include one or more electrodes. In one example, the housing 22 of the leadless pacing device 20 can support a first electrode 26 and a second electrode 28, and the distal extension 24 can support a distal electrode or multiple electrodes. In some cases, the distal extension 24 can include multiple electrodes (e.g., a first proximal ring electrode 30, a second proximal ring electrode 32, a third proximal ring electrode 34, a distal ring electrode 36, and / or one or more other electrodes). Although the electrodes described can be shown as ring electrodes, other electrode types can be used depending on the application.

[0061] In some cases, the first electrode 26 can be formed on, along, and / or from the first portion 22a of the housing 22, and the second electrode 28 can be formed on, along, and / or from a fixation member 50 (described in more detail below) extending from the housing 22. In one example, the first portion 22a of the housing 22 can be at least partially formed of a conductive material, and an exposed surface of such conductive material can at least partially form the first electrode 26. Additionally or alternatively, the second electrode 28 can be formed by one or more exposed conductive surface portions of the fixation member 50, which can be exposed to the patient's heart tissue.

[0062] Although the electrodes 26, 28 are shown as being positioned at the first portion 22a of the housing 22 and at the fixation member 50 extending from the second portion 22b of the housing, respectively, in some cases, the number and location of electrodes supported by the housing 22 can vary depending on the application. For example, the leadless pacing device 20 can have electrodes disposed only on or supported by one of the first housing portion 22a or the second housing portion 22b, or one electrode on or supported by the first housing portion 22a and another electrode on or supported by the second housing portion 22b, wherein the leadless pacing device 20 includes two housing portions. It may be desirable to configure the electrodes on the housing 22 at various longitudinal locations of the housing 22 to facilitate establishing good contact between the electrodes and the wall of the coronary sinus 15. In some cases, the leadless pacing device 20 may not have any electrodes disposed on the housing 22. Alternative and / or additional electrode configurations for the leadless pacing device 20 are discussed in the references incorporated herein.

[0063] In one example configuration of electrodes 26, 28 supported by the housing 22, the first electrode 26 positioned on the first portion 22a of the housing 22 may be an anode electrode, and the second electrode 28 positioned at the fixing member 50 may be a cathode electrode. However, since the electrodes may be bipolar electrodes, the first electrode 26 in the example configuration may be changed to a cathode electrode, and the second electrode 28 in the example configuration may be changed to an anode electrode. The polarity of the paired bipolar electrodes may be switched regardless of the position of the electrodes.

[0064] When provided, the electrodes of the leadless pacing device 20 can be used to deliver electrical stimulation to the heart 10, and / or sense one or more physiological signals. In some cases, the leadless pacing device 20 can use one or more of the electrodes (e.g., electrodes 26-36 or other electrodes) to communicate with one or more other devices (such as, but not limited to, one or more other leadless cardiac pacemakers and / or implantable cardioverter-defibrillators). In some cases, the leadless pacing device 20 can communicate using conducted communication techniques, and communication signals can be delivered and / or received through one or more of the electrodes (e.g., electrodes 26-36 or other electrodes). Additionally or alternatively, the leadless pacing device 20 may include one or more communication lines (e.g., see Figures 15A-15B and 16), wherein the communication line is configured to operate as an antenna for wirelessly communicating with one or more other devices and / or receiving electrical power from the one or more other devices, as discussed in more detail below.

[0065] In some cases, housing 22 can include a proximal member 38 (e.g., a docking hub or other member) that extends generally from a proximal end of housing 22. Figure 1 In the example shown, the proximal member 38 can extend proximally from the first portion 22a of the housing 22. During implantation, the proximal member 38 can be releasably coupled to a positioning device ( Figure 1 When coupled, the movement of the positioning device can be transferred to the housing 22, thereby allowing a user (such as a physician) to manipulate the housing 22 to an appropriate position within the heart 10, such as into or near the coronary sinus 15. The positioning device can have the ability to manipulate the housing 22 longitudinally and / or rotationally.

[0066] In some cases, the leadless pacing device 20 can be delivered from a delivery catheter ( Figure 1 The leadless pacing device 20 can be delivered by a delivery catheter (not shown), and the portion of the delivery catheter surrounding the housing 22 can conform to the housing 22 to establish a secure connection between the delivery catheter and the housing 22. When the leadless pacing device 20 is in place, the delivery catheter can be retracted, or the positioning device can be used to push the housing 22 out of the delivery catheter and / or otherwise adjust the position of the leadless pacing device 20. Additionally or alternatively, the positioning device can apply a rotational torque to the housing 22 to anchor the leadless pacing device 20 to the cardiac tissue. In some cases, the elongated member used to adjust the position of the leadless pacing device 20 can have an interlocking mechanism (e.g., the interlocking mechanism 100 described below, or other suitable interlocking mechanisms). For example, the elongated member for adjusting the position of the leadless pacing device 20 can include, but is not limited to: an elongated member having a magnetic distal end configured to establish a magnetic connection with the housing 22 or the proximal member 38; an elongated member having a gripping mechanism at the distal end configured to grip the housing 22 or the proximal member 38; an elongated member having a snare mechanism at the distal end configured to engage the housing 22, and / or other suitable elongated members configured to interact with the leadless pacing device 20 to adjust the position of the leadless pacing device 20. Although not shown in the figures, the proximal member 38 can further include a tether anchor, which can facilitate the coupling of the tether to the tether anchor during delivery to allow the user to pull the housing 22 back into the delivery catheter for further positioning. In some cases, the tether can be a suture, and the suture can be coupled to the tether anchor by embracing the tether anchor. To release the tether from the housing 22, the user may simply cut the tether or pull on one end of the tether until the tether untangles itself from the tether anchor.

[0067] Although the distal extension 24 is Figure 1, but in some cases, the leadless pacing device 20 may not include the distal extension 24. In the case where the leadless pacing device 20 includes the distal extension 24, the distal extension 24 can be extended from the distal end of the housing 22 (e.g., the second portion 22b of the housing 22, such as Figure 1 In addition, when included, distal extension 24 can extend into coronary sinus 15 and be secured within coronary sinus 15. In some cases, distal extension 24 can extend through coronary sinus 15 and into great cardiac vein 17 (as shown). Figure 1 ) or in one or more other blood vessels extending from the coronary sinus 15 or the great cardiac vein 17.

[0068] The distal extension 24 may include a proximal end 24a and a distal end 24b. The distal end 24b of the distal extension 24 may include one or more engagement members, but this is not required and the engagement members may be omitted from the distal extension 24. When included, the engagement members may help secure the distal end 24b of the distal extension 24 within the coronary sinus 15 or the great cardiac vein 17. The engagement members may include one or more distal extension anchors (e.g., tines, spiral coils, claws, or other anchors) made of silicon, a biocompatible polymer, a biocompatible metal, another biocompatible material, a shape memory material (e.g., nitinol or other shape memory materials), and / or a bioabsorbable material. Bioabsorbable materials may be employed to facilitate removal of the leadless pacing device 20 from a patient because endothelial growth may otherwise occur on the distal extension anchors.

[0069] In some cases, when included, the engagement member can include one or more electrodes or wire loops and can function as an antenna to communicate with and / or receive electrical energy from one or more other devices. For example, the leadless pacing device 20 can receive energy transfer and / or communicate via electrodes and / or wire loops of the engagement member 41 using inductive and / or conductive communication techniques.

[0070] As mentioned above, distal extension 24 may include one or more electrodes (e.g., electrodes 30-36). In some of these cases, electrodes 30-36 may be disposed proximal to distal end 24b of distal extension 24 and distal to housing 22, whereas in other cases, one or more of the electrodes on distal extension 24 may span a length of distal extension 24 (e.g., the entire length or a portion of the length).

[0071] In some cases, the electrodes on the distal extension 24 can be used to deliver electrical stimulation to the heart 10. For example, the leadless pacing device 20 can deliver electrical stimulation to the left ventricle 14 of the heart 10 via a group of one or more of the electrodes (e.g., from the electrodes 30-36 or other groups of electrodes). In some cases, the leadless pacing device 20 can deliver electrical stimulation to the left ventricle 14 of the heart 10 simultaneously or with a delay (e.g., via multi-electrode pacing) using two or more of the electrodes 30-36. In some additional or alternative cases, the leadless pacing device 20 can use one or more of the electrodes 30-36 to communicate with one or more other devices (e.g., the electrodes 30-36 can be used as antennas). For example, the leadless pacing device 20 can receive energy transfer and / or communicate using inductive or conductive communication techniques via one or more of the electrodes 30-36.

[0072] The electrodes 26-36 and / or other electrodes on the leadless pacing device 20 can be capable of sensing electrical signals, providing electrical stimulation signals, or sensing electrical signals and providing electrical stimulation signals. Signal processing, communication, and / or therapy pulse generation can occur at any portion of the leadless pacing device (where appropriate processing modules can be located). In one example, signal processing, communication, and therapy pulse generation for the electrodes of the leadless pacing device 20 (e.g., the electrodes 26-36 and / or other electrodes) can occur in a module within the housing 22 or supported by the housing 22, but this is not required.

[0073] The electrodes 26-36 and / or other electrodes of the leadless pacing device 20 can be configured to perform near-field and / or far-field sensing of cardiac activation events. "Near-field" sensing of cardiac activation events refers to sensing cardiac activation events that originate from a local chamber where the corresponding electrode is located (e.g., the same chamber where the electrode is sensing). "Far-field" sensing of cardiac activation events refers to sensing cardiac activation events that originate from a chamber other than the local chamber where the corresponding electrode is located. For example, if an electrode of the leadless pacing device 20 is located in the coronary sinus 15 and the electrode is adjacent to a wall of the coronary sinus 15 that forms the wall of the right atrium 11, the electrode is sensing a right atrial activation event in the near field, and is sensing a left atrial activation event, a left ventricular activation event, and a right ventricular activation event in the far field.

[0074] exist Figure 1In an example in which the leadless pacing device 20 is implanted in the coronary sinus 15 and a blood vessel extending from the coronary sinus 15 (e.g., the great cardiac vein 17), a first electrode 26 (e.g., a proximally located electrode supported by the shell 22) can be positioned in the coronary sinus 15 adjacent to the right atrium 11, a second electrode 28 (e.g., a distally located electrode supported by the shell 22) can be positioned in the coronary sinus 15 adjacent to the left atrium 12, and electrodes 30-36 supported by the distal extension 24 can be positioned in the great cardiac vein 17 and / or branches of the great cardiac vein 17, so that the electrodes 30-36 are positioned adjacent to the left atrium 12 and / or the left ventricle 14. In this implant structure, the first electrode 26 can sense the near-field signal of an atrial activation event (P wave) in the right atrium 11 and provide a pacing pulse to the cardiac tissue of the right atrium 11, the second electrode 28 can sense the near-field signal of an atrial activation event (P wave) in the left atrium 12 and provide a pacing pulse to the cardiac tissue of the left atrium 12, and the electrodes 30-36 supported by the distal extension 24 can sense the near-field signal of a ventricular activation event (R wave) originating from the atrium and conducted in the left ventricle 14 through the atrioventricular node and the His-Purkinje pathway, and provide a pacing pulse to the cardiac tissue of the left ventricle 14.

[0075] Additionally or alternatively, the electrodes 26-36 or other electrodes of the leadless pacing device 20 can sense signals by far-field sensing. For example, the electrodes 26, 28 that can be supported by the housing 22 can sense far-field ventricular activation activity (R wave), and the electrodes 30-36 supported by the distal extension 24 can sense far-field atrial activation activity (P wave). However, such sensed signals may be attenuated and delayed and / or the amplitude and duration may be insufficient to reliably sense atrial and ventricular activation activity, and the signals sensed by near-field sensing may need to be considered when considering the signals sensed by far-field sensing.

[0076] In some cases, the leadless pacing device 20 can be implanted as a single device (e.g., without one or more other leadless pacing devices or one or more implantable cardioverter-defibrillators) that can provide electrical stimulation to the right atrium 11, the left atrium 12, the right ventricle 13, and / or the left ventricle 14 as needed. For example, the leadless pacing device 20 can be configured to deliver electrical stimulation to treat atrial fibrillation or atrial flutter according to a treatment program. However, in other cases, the leadless pacing device 20 can be implanted together with one or more other implantable cardioverter-defibrillators and / or one or more other leadless pacing devices implanted at one or more different locations in and / or around the heart 10.

[0077] In one example of using the leadless pacing device 20, the leadless pacing device 20 can be part of a single or multiple device system for delivering cardiac resynchronization therapy (CRT) to the heart 10. In these examples, the leadless pacing device 20 can sense ECG signals in one or both of the right atrium 11 and the left atrium 12. Once the leadless pacing device 20 senses the ECG signals propagating through the right atrium 11 and / or the left atrium 12, the leadless pacing device 20 can deliver a pacing pulse to the left ventricle 14 after a delay period (e.g., AV delay). The length of the delay period can be determined or selected so that the leadless pacing device 20 can deliver a pacing pulse to the left ventricle 14 when the propagated ECG signals reach the right ventricle 13 and cause the right ventricle 13 to contract. In this way, the leadless pacing device 20 can operate to provide synchronized contraction of the right ventricle 13 and the left ventricle 14. In some additional cases, the leadless pacing device 20 can adjust the delay period based on the sensed heart rate. For example, when the leadless pacing device 20 senses an increase in heart rate, the leadless pacing device 20 can shorten the length of the delay period. Conversely, when the leadless pacing device 20 senses a decrease in heart rate, the leadless pacing device 20 can lengthen the delay period.

[0078] As discussed, the leadless pacing device 20 can deliver pacing pulses to the right atrium 11 and / or the left atrium 12 via the coronary sinus 15. In these embodiments, the leadless pacing device 20 can start counting the delay period at the time when the leadless pacing device 20 delivers the pacing pulse to the right atrium 11 and / or the left atrium 12, or shortly thereafter. As with the previous embodiments, this can cause synchronized contractions of the right ventricle 13 and the left ventricle 14. In the case where the leadless pacing device 20 is part of a system with an additional leadless pacing device within the right ventricle 13, the leadless pacing device 20 can transmit a trigger signal to the additional leadless pacing device after the leadless pacing device 20 delivers the pacing pulse to the right atrium 11 and / or the left atrium 12. After receiving the trigger, the additional leadless pacing device can deliver the pacing pulse to the right ventricle 13 after its own delay period. In at least some of these examples, the delay period of the additional leadless pacing device can be consistent with the delay period of the leadless pacing device 20, such that both the additional leadless pacing device and the leadless pacing device 20 synchronously deliver pacing pulses to the right ventricle 13 and the left ventricle 14. However, in other embodiments, the delay period of the additional leadless pacing device can be different from the delay period of the leadless pacing device 20, such as by desynchronizing the conduction of the right ventricle 13 and the left ventricle 14 so as to cause the right ventricle 13 and the left ventricle 14 to contract synchronously.

[0079] Figure 2is a schematic diagram of an exemplary leadless pacing device 20. The exemplary leadless pacing device 20 can include a housing 22 having a first housing portion 22a and a second housing portion 22b, sometimes with a distal extension 24 extending distally of the housing 22. The housing 22 can be a unitary housing or can include two or more housing portions (e.g., the first portion 22a, the second portion 22b, and / or one or more other housing portions) in which one or more components of the leadless pacing device 20 are housed. The housing 22 can generally include a biocompatible material, such as a biocompatible metal and / or polymer, and can hermetically seal the components of the leadless pacing device 20 from fluids and tissues of the patient's body when implanted in the patient's body.

[0080] Figure 2 The housing 22 shown can have a generally rectilinear elongated shape extending along a central longitudinal axis parallel to line A. In some cases, the housing 22 (including the first body portion 22a and / or the head or second portion 22b) can be generally cylindrical having a circumferential surface extending around the central longitudinal axis of the housing 22. Figure 2 , both the first portion 22a and the second portion 22b extend along a central longitudinal axis and parallel to line A. However, the housing 22 can have one or more other suitable shapes, including but not limited to having curved or angled portions to facilitate engagement of tissue of the patient's heart by electrodes of the leadless pacing device 20. Additional or alternative shape configurations of the housing 22 are discussed in the references incorporated herein. In some of these configurations, the second portion 22b (i.e., the head) can extend along a central longitudinal axis parallel to line A, while the proximal portion 22a can extend along a longitudinal axis that is inclined relative to the central longitudinal axis and line A. In other cases, the first portion 22a can extend along a central longitudinal axis parallel to line A, while the distal portion 22b can extend along a longitudinal axis that is inclined relative to the central longitudinal axis and line A.

[0081] As described above, the leadless pacing device 20 can have one or more electrodes, such as electrodes 26, 28, and / or other electrodes, which in the illustrated example are supported by the housing 22 (e.g., a first electrode can be formed from a conductive material of the first portion 22a of the housing, and a second electrode 28 can be formed from a conductive portion of a fixation member 50 supported by the second portion 22b of the housing 22). It is contemplated that the housing 22 can have a different number of electrodes, or no electrodes at all, in some cases.

[0082] In the case where the housing 22 includes two or more parts, the first part 22a can be the body and the second part 22b can be the head. The first part 22a can be made of a biocompatible metal material or other materials suitable for encapsulating the electronic components of the leadless pacing device 20 and / or used as the first electrode 26. The second part 22b (i.e., the head) can be made of a biocompatible polymer or other material. In some cases, the second part 22b can be made of a polymer and molded on the distal end of the first part 22a of the housing 22 and / or on a component extending from the first part 22a by an overmolding process, or communicate with a component housed in the first part 22a of the housing 22 (for example, the fixing member 50 is electrically connected to a power source housed by the first housing part 22a). For example, when the second part 22b is formed by a molding technique, the distal extension 24 can be connected to the housing 22 by molding the second part 22b on the proximal end of the distal extension 24.

[0083] In some cases and as described above, the housing 22 can include a proximal member 38 (e.g., a docking hub) extending from the proximal end of the first portion 22a of the housing 22. In some cases, the proximal member 38 can have an extension 46 having a first outer diameter and protruding from the housing 22, wherein the proximal end of the extension 46 can be connected to or form an appendage 48 having a second diameter. Figure 2 In the example shown in FIG. 4 , the second outer diameter of the appendage 48 may be greater than the first outer diameter of the extension 46 , but other suitable configurations are also contemplated.

[0084] During implantation, refer to Figure 23-31 Discussed in more detail, the positioning device can be releasably coupled to the proximal member 38. When coupled, the movement of the positioning device can be transferred to the housing 22, thereby allowing the user to longitudinally position and / or rotate the leadless pacing device 20 during implantation. In some cases, instead of or in addition to the extension 46 and the appendage 48, the proximal member 38 can include one half of an interlocking mechanism, and the positioning device can have a second half of the interlocking mechanism that can be releasably coupled to the interlocking mechanism of the proximal member 38. The interlocking mechanism can be configured to establish a magnetic connection, a keyed connection, and / or other suitable connection. Additional and / or alternative positioning devices and interlocking mechanisms are described in the references incorporated herein.

[0085] In some cases, the housing 22 can include a fixation member 50, and / or the fixation member 50 can extend from the housing 22. The fixation member 50 can include a distal tip 57 and can be configured to maintain the leadless pacing device 20 within the coronary sinus 15 when the leadless pacing device 20 is implanted within the coronary sinus 15 of the heart 10. The fixation member 50 can be or can include one or more anchors (e.g., tines, a spiral coil, claws, or other anchors) made of silicon, a biocompatible polymer, a biocompatible metal, another biocompatible material, a shape memory material (e.g., nitinol or other shape memory material), and / or a bioresorbable material. The bioresorbable material can be employed to facilitate removal of the leadless pacing device 20 from the patient because tissue growth may otherwise occur on the anchors.

[0086] In one example of the fixing member 50, the fixing member 50 may be a helical coil or an anchor, such as Figure 2 5, which has a distal end terminating at a distal tip 57. In some cases, the fixing member 50 in the helical coil can have an outer diameter in the range of about 0.25 to about 0.275 inches and a pitch of about 0.075 inches. In one example, the fixing member 50 in the helical coil can have an outer diameter of about 0.247 inches or about 0.25 inches, and the helical coil can have a pitch of about 0.050 inches so as to surround the helical coil at least one turn, but the fixing member 50 in the shape of a helical coil can have one or more different diameters and / or different suitable pitches, but this is not required.

[0087] The helical coil of the fixation member 50 can be fixed to the housing 22 by any suitable means. In one example, a proximal portion of the fixation member 50 (e.g., a proximal portion of the helical coil) can be embedded (e.g., molded) within the second portion 22b of the housing 22, and a distal portion of the fixation member 50 (e.g., a distal portion of the helical coil) can extend from the second portion 22b and can be configured to engage cardiac tissue of the patient when the leadless pacing device is positioned in the patient. The distal portion of the fixation member 50 can be configured to extend about 0.5 turns, about 0.75 turns, about 1.0 turns, about 1.25 turns, about 1.5 turns, 0.5 to 2.0 turns, 0.75 to 1.5 turns, 1.0 to 1.25 turns, and / or other suitable numbers of turns around the second portion 22b of the housing 22. When the second portion 22b of the housing 22 is formed by an overmolding process, the proximal portion of the fixation member 50 can be embedded within the second portion 22b during the overmolding process. Other techniques for embedding and / or securing the securing member 50 within the second portion 22b may be used as desired.

[0088] In some cases, the helical coil of the fixation member 50 may terminate at a distal tip 57 that is located at or proximal to the distal end of the second portion 22b of the housing 22. For example, the distance D of the second portion 22b of the housing 22 may extend distally of the distal tip 57, such as Figure 2 0.005 inches. In other cases, the distal tip 57 can be flush with the distal end of the distal portion 22b.

[0089] In some cases, the helical coil of the fixation member 50 can terminate at a distal tip 57 that is positioned at or distal to the distal end of the second portion 22b of the housing 22. For example, the distal tip 57 can be positioned distal to the distal end of the second portion 22b of the housing 22 by a distance that is in the range of about 0.005 inches to about 0.030 inches, in the range of about 0.005 inches to about 0.015 inches, and / or in the range of other suitable distances. In one example, the distal tip 57 can be positioned distal to the distal end of the second portion 22b of the housing 22 by a distance of about 0.005 inches.

[0090] In a relaxed equilibrium state, the distal tip 57 of the fixing member 50 can extend tangentially from the outer circumference of the spiral portion of the fixing member 50 so that the distal tip 57 extends radially outward beyond the circumferential surface of the shell 22, such as radially outward beyond the circumferential surface of the first portion 22a and / or the second portion 22b of the shell 22.

[0091] When the fixation member 50 is in the form of a spiral coil and / or other configuration, the fixation member 50 can be at least partially constructed of a material configured to puncture and engage cardiac tissue, the material being electrically conductive, radiopaque, and / or flexible and / or having shape memory properties. Examples of such materials can include, but are not limited to, stainless steel, nickel-cobalt alloys (e.g., MP35N or other suitable nickel-cobalt alloys), platinum-iridium alloys (e.g., alloys of 70% platinum and 30% iridium, alloys of 80% platinum and 20% iridium, and / or other suitable platinum-iridium alloys), titanium (e.g., Grade 1 hardened titanium; Grade 1 annealed titanium, and / or other suitable titanium), nickel-titanium alloys (e.g., nitinol and / or other suitable nickel-titanium alloys), suitable precious metals, combinations of these materials (e.g., a material combination having a nickel-titanium alloy core layer and a platinum-iridium alloy outer layer), and / or other suitable materials. In some cases, the material forming the fixation member 50 can be a radiopaque material to facilitate alignment of the fixation member 50 with the target location. The fixation member 50 in the form of a helical coil can be formed of a material (e.g., wire or other suitable material) having a certain diameter (e.g., maximum cross-sectional distance) that is suitable for puncturing and engaging cardiac tissue, conducting electricity, and / or being flexible or bendable. Examples of suitable diameters include, but are not limited to, 0.001-0.100 inches, 0.010-0.020 inches, 0.014-0.016 inches, and / or other suitable diameters. In one example of a fixation member 50, the fixation member 50 can be at least partially formed of an alloy of 80% platinum and 20% iridium with a diameter of 0.015 inches, but this is not required.

[0092] In some cases, a fixation member 50 having a helical coil configuration can have the ability to straighten or elongate from a helical configuration when the fixation member 50 engages tissue and an axial force is applied to the leadless pacing device 20. In some cases, the fixation member 50 can plastically deform and elongate from its helical configuration to a straightened configuration when subjected to an axial force. Such a configuration of the fixation member 50 can facilitate removal of the leadless pacing device 20 from an implantation location within the coronary sinus 15 and can reduce the risk of damage to the patient by the fixation member 50 due to puncture or abrasion. In some cases, the amount of force required to elongate the fixation member from a relaxed helical configuration can depend on the material type and / or the thickness of the material. Example amounts of force required to extend (e.g., plastically deform) the fixation member 50 from a relaxed helical configuration to an extended, straight configuration can be set within a range of approximately 0.1-1.0 pounds-force (lbf), within a range of approximately 0.1-0.5 lbf, approximately 0.25 lbf, approximately 0.50 lbf, less than approximately 1.0 lbf, and / or other suitable amounts of force so that the axial force is applied without causing undue trauma to the patient but with sufficient force so that the fixation member 50 is not inadvertently extended.

[0093] In at least some examples, fixation member 50 can be configured to at least partially maintain housing 22 in a desired position relative to the lumen of coronary sinus 15. For example, when fixation member 50 is in the helical anchor configuration, fixation member 50 can engage cardiac tissue of the patient and press at least a portion of housing 22 (e.g., second portion 22b) against a wall of coronary sinus 15 that forms a wall of a chamber of heart 10 (e.g., by positioning a portion of the wall of coronary sinus 15 between fixation member 50 and second portion 22b of housing 22).

[0094] Although one fixing member 50 is shown on the housing 22, the housing 22 may support one or more additional fixing members that are axially spaced apart from the fixing member 50 shown in the figures. In other cases, the housing 22 may not include the fixing member 50.

[0095] In some cases, as described above, the fixation member 50 can include or form one or more electrodes (e.g., the second electrode 28 or other suitable electrodes), and / or can act as an antenna to communicate with and / or receive electrical energy from one or more other devices. For example, the leadless pacing device 20 can receive energy transfer and / or communicate through the electrodes of the fixation member 50 using inductive and / or conductive communication techniques.

[0096] In at least some cases, the housing 22 can have a guidewire port 54 extending through a side of the housing 22 (e.g., an opening leading to the outside of a side of the housing 22), wherein the side extends from a first end to a second end of the housing 22. In some cases, the guidewire port 54 can be disposed in or near the second portion 22b of the housing 22 and can be configured to receive a guidewire. In the case where the leadless pacing device 20 includes a distal extension 24, the distal extension 24 can include a corresponding guidewire port extending to the outside of a distal tip of a distal end 24b of the distal extension 24. In this case, the guidewire can be placed along the great cardiac vein 17 (or other blood vessel in communication with the coronary sinus 15). The leadless pacing device 20 can be routed on the guidewire by threading the distal extension 24 onto the proximal end of the guidewire and then advancing the leadless pacing device 20 on the guidewire until it is in place. In embodiments where the leadless pacing device 20 does not include a distal extension 24, the housing 22 can include a second guidewire port.

[0097] When included by the leadless pacing device 20, the distal extension 24 can extend from the housing 22 at any suitable angle. In some instances, the distal extension 24 can extend from the housing 22 at an angle A relative to a line A, where the line A can be a line along or parallel to a central longitudinal axis of the housing 22. The angle A can be an oblique angle such that the distal extension 24, in a natural or equilibrium state (where no external force is applied to bend or flex the distal extension 24), extends from the second portion 22b of the housing 22 at an angle that is not parallel to the central longitudinal axis of the housing 22 and / or the central longitudinal axis of the second portion 22b of the housing 22. In other words, in the equilibrium state, the base portion of the distal extension 24 can be affixed or fastened to the second portion 22b at the oblique angle A, which can be securely or fixedly mounted to the second portion 22b of the housing 22 in a fixed orientation relative to the second portion 22b of the housing 22. For example, the base portion of the distal extension 24 can be away from or otherwise directly extend from the distal end of the second portion 22b at an oblique angle A in the equilibrium state, so that the central longitudinal axis of the base portion of the distal extension 24 is oriented at the oblique angle A relative to the central longitudinal axis of the housing 22, and the base portion may include a portion extending into and surrounded by the second portion 22b (e.g., molded or fixed within the second portion 22b). For example, in some cases, the oblique angle A can be in the range of 10 degrees to 50 degrees, in the range of 10 degrees to 40 degrees, in the range of 10 degrees to 30 degrees, in the range of 15 degrees to 35 degrees, or in the range of about 20 degrees to 25 degrees. When the distal extension 24 extends at an oblique angle relative to the line A, the configuration can facilitate passing a guidewire through the distal extension 24 by aligning the guidewire lumen portion of the distal extension 24 with the guidewire lumen portion of the housing 22, so that a bend in the guidewire lumen at the proximal end of the distal extension 24 can be alleviated and / or eliminated. Thus, the distal extension 24 may extend distally from the second portion 22 b of the housing 22 toward a circumferential side of the housing 22 that is opposite (eg, 180 degrees opposite) the guidewire port 54 positioned on the circumferential surface of the second portion 22 b of the housing 22 .

[0098] Distal extension 24 can be a thin, elongated, and flexible member, particularly relative to housing 22. For example, distal extension 24 can be between two and ten times the length of housing 22. Additionally and as described above, distal extension 24 can have one or more engagement members. In some cases, when included, the engagement member can be disposed at or near distal end 24b of distal extension 24. In some cases, distal extension 24 can include one or more electrodes (e.g., electrodes 30-36).

[0099] As discussed above, electrodes 30-36 and / or other electrodes may be disposed proximate distal end 24b of distal extension 24, or may be dispersed (eg, longitudinally spaced apart from one another) along the length of distal extension 24, such as Figure 2 . Other configurations and / or constructions of the electrodes on the distal extension 24 are also conceivable and may be employed. In one example configuration of electrodes (e.g., employing electrodes 30-36), each of the electrodes may be a ring electrode, and electrode 36 (e.g., a distal ring electrode) may be disposed on the distal extension 24 near the distal end of the distal extension 24, electrode 34 (e.g., a third proximal ring electrode) may be spaced forty (40) millimeters proximal to electrode 36, electrode 32 (e.g., a second proximal ring electrode) may be spaced ten (10) millimeters proximal to electrode 34, and electrode 30 (e.g., a first proximal ring electrode) may be spaced ten (10) millimeters proximal to electrode 32. This configuration of electrodes 30-36 may be aligned with the left atrium 12 when the distal extension 24 is inserted into the great cardiac vein 17 or other blood vessel to allow the leadless pacing device 20 to sense and / or pace the left atrium 12 of the patient's heart 10. In some cases, distal extension 24 may be biased to form a certain shape, such as a helical coil or one or more loops.

[0100] Figure 3 is a schematic block diagram of one or more electronic modules that can be housed within the housing 22 of the leadless pacing device 20. In some instances, the leadless pacing device 20 can include an energy storage module 56 (e.g., a power supply for supplying / providing a supply voltage), a processing module 58, a communication module 60, a pulse generator module 62, an electrical sensing module 64, and / or a mechanical sensing module 66. Figure 3 Also shown are conductors 68 - 72 , which may extend from one or more of the modules 56 , 58 , 60 , 62 , 64 , and / or to one or more electrodes (eg, electrodes 26 - 36 or other electrodes).

[0101] although Figure 3Only three conductors are shown in FIG. 2 , but a different conductor can extend from the module in the housing 22 to each of the electrodes of the leadless pacing device 20. Additionally or alternatively, one or more conductors can be provided to facilitate communication and / or power transfer between the electronic module of the leadless pacing device 20 and one or more other electrical devices. Accordingly, in at least some cases, all of the electronic components and energy storage modules of the leadless pacing device 20 can be housed within the housing 22, with only one or more conductors extending to the electrodes. In one example, conductor 68 can extend to a first electrode 26 supported by the housing 22, conductor 70 can extend to a second electrode 28 supported by the housing 22 (e.g., to a tail 81 of the fixation member 50 and / or other suitable element in electrical communication with the second electrode 28), and conductor 72 can represent a conductor extending to electrodes 30-36 on the distal extension, wherein a single conductor can extend to each electrode 30-36 and a conductor extending to the distal ring electrode 36 can be wound along and / or around the lumen 76 of the distal extension 24 until the conductor reaches the distal ring electrode 36. Additionally or alternatively, as desired, other conductors may be coiled around lumen 76. Each conductor extending to an electrode may be electrically isolated from the other conductors, and in some cases, each conductor may extend through its own lumen to the associated electrode, but this is not required.

[0102] exist Figure 3 In the example shown in , the communication module 60 can be electrically connected to the electrodes 26-36 and can be configured to deliver communication signals such as electrical communication pulses to the patient's tissue to communicate with other devices such as sensors, programmers, other medical devices and / or the like. The electrical communication pulse as used herein can be any modulated signal that transmits information to another device by itself or in combination with one or more other modulated signals. In some embodiments, the electrical communication pulse can be limited to a subthreshold signal that does not cause cardiac capture but still transmits information. The electrical communication pulse can be delivered to another device located inside or outside the patient's body. The communication module 60 can be additionally configured to sense electrical communication pulses delivered by other devices that can be located inside or outside the patient's body. Descriptions of additional and / or alternative components or features of the communication module 60 are described in the references incorporated herein.

[0103] The pulse generator module 62 can be configured to generate electrical stimulation pulses and deliver the electrical stimulation pulses to the patient's tissue via one or more of the electrodes 26-36 to achieve one or more electrical stimulation therapies. Electrical stimulation pulses as used herein are intended to include any electrical signal that can be delivered to the patient's tissue for the purpose of treating any type of disease or abnormality. The pulse generator module 62 may include one or more capacitor elements and / or other charge storage devices to assist in generating and delivering appropriate electrical stimulation pulses. In the illustrated embodiment, the pulse generator module 62 may use energy stored in the energy storage module 56 to generate electrical stimulation pulses. Descriptions of additional and / or alternative components or features of the pulse generator module 62 are described in the references incorporated herein.

[0104] The electrical sensing module 64 can be electrically connected to one or more electrodes 26-36, and the electrical sensing module 64 can be configured to receive electrocardiographic signals conducted through the electrodes 26-36. In some embodiments, when the leadless pacing device 20 has been implanted in the coronary sinus 15 and / or a blood vessel extending therefrom, the electrocardiographic signals can represent local information (e.g., near-field information) from a chamber where or around the electrodes of the leadless pacing device 20 are located. Descriptions of additional and / or alternative components or features of the electrical sensing module 64 are described in the references incorporated herein.

[0105] Mechanical sensing module 66 may include or be electrically connected to various sensors, such as accelerometers, blood pressure sensors, heart sound sensors, blood oxygen sensors, and / or other sensors that measure one or more physiological parameters of the heart and / or the patient. Mechanical sensing module 66, when present, may collect signals from the sensors indicative of the various physiological parameters. Both electrical sensing module 64 and mechanical sensing module 66 may be connected to processing module 58 and may provide signals representative of sensed electrocardiographic and / or physiological signals to processing module 58. Although relative to Figure 3 Described as separate sensing modules, however, in some embodiments, the electrical sensing module 64 and the mechanical sensing module 66 may be combined into a single module. Descriptions of additional and / or alternative components or features of the mechanical sensing module 66 are described in the references incorporated herein.

[0106] The processing module 58 can be configured to control the operation of the leadless pacing device 20. For example, the processing module 58 can be configured to receive near-field and / or far-field ECG signals from the electrical sensing module 64 and / or physiological signals from the mechanical sensing module 66. Based on the received near-field and / or far-field signals, the processing module 58 can determine, for example, the occurrence and type of arrhythmia (e.g., when atrial and / or ventricular events occur). The processing module 58 can further receive information from the communication module 60. In some embodiments, the processing module 58 can additionally use such received information to determine the occurrence and type of arrhythmia. Based on the determined arrhythmia (e.g., the determined atrial and / or ventricular cardiac events), the processing module 58 can control the pulse generator module 62 to generate electrical stimulation pulses according to one or more electrical stimulation therapies to treat the determined arrhythmia. In addition to controlling the pulse generator module 62 to generate different types of electrical stimulation pulses and in different sequences, in some embodiments, the processing module 58 can also control the pulse generator module 62 to generate various electrical stimulation pulses with varying pulse parameters. In some embodiments, the processing module 58 can further control the communication module 60 to send information to other devices. In still other cases, the processing module 58 can control a switching circuit by which the communication module 60 and the pulse generator module 62 deliver electrical communication pulses and / or electrical stimulation pulses to the patient's tissue. In additional cases, the processing module 58 can include a memory circuit, and the processing module 58 can store information on and read information from the memory circuit. In other cases, the leadless pacing device 20 can include a separate memory circuit (not shown) that communicates with the processing module 58 so that the processing module 58 can read information from and write information to the separate memory circuit. Descriptions of additional and / or alternative components or features of the processing module 58 are described in the references incorporated herein.

[0107] The energy storage module 56 can provide power to the leadless pacing device 20 for its operation. In some embodiments, the energy storage module 56 can be a non-rechargeable lithium-based battery. In other embodiments, the non-rechargeable battery can be made of other suitable materials. In some embodiments, the energy storage module 56 can include a rechargeable battery. In still other embodiments, the energy storage module 56 can include other types of energy storage devices, such as supercapacitors. Descriptions of additional and / or alternative components or features of the energy storage module 58 are described in the references incorporated herein.

[0108] The tail portion 81 (which can be an integral part of the fixation member 50) can take any suitable configuration and can be configured to be viewed as a radiopaque marker in an image of the patient while the leadless pacing device 20 is being inserted into the patient, being implanted in the patient, being implanted in the patient, and / or being removed from the patient. The tail portion 81 of the fixation member 50 can include a radially extending portion 81a and a proximally extending portion 81b.

[0109] In some instances, the radially extending portion 81a can be positioned proximal to the helical portion of the fixation member 50 such that the radially extending portion 81a is disposed between the helical portion of the fixation member 50 and the proximally extending portion 81b. Alternatively, the proximally extending portion 81b can be positioned proximal to the helical portion of the fixation member 50 such that the proximally extending portion 81a is disposed between the helical portion of the fixation member 50 and the radially extending portion 81b. Thus, the radially extending portion 81a can be positioned at a distal end of the proximally extending portion 81b (e.g., as shown in the figures), or the radially extending portion 81a can be positioned at a proximal end of the proximally extending portion 81b. Furthermore, the radially extending portion 81a can extend radially inwardly any suitable distance from the inner diameter of the helical coil forming the fixation member 50 so that the radially extending portion 81a can be observed in an image of an end view of the leadless pacing device 20 within a patient. Example distances that the radially extending portion 81a may extend include appropriate distances that are less than or greater than the distance from the inner diameter of the helical coil forming the fixation member 50 to the central axis of the second portion 22b of the housing 22. Such distances may include, but are not limited to, distances in the range of about 0.010 inches to about 0.1235 inches, about 0.010 inches to about 0.10 inches, about 0.010 inches to about 0.050 inches, about 0.015 inches to about 0.045 inches, and / or other appropriate ranges. In some examples, the radially extending portion 81a may extend inward from the inner diameter of the helical coil forming the fixation member 50 by about 0.015 inches, about 0.030 inches, or about 0.045 inches.

[0110] The proximally extending portion 81b can extend proximally from the helical coil portion of the fixation member 50 and / or the radially extending portion 81a any suitable distance so that the proximally extending portion 81b is observed in an image of a side view of the leadless pacing device 20 in a patient. Example distances that the proximally extending portion 81b can extend include, but are not limited to, less than about 0.045 inches, about 0.045 inches, or greater than about 0.045 inches. In some cases, the proximally extending portion 81b can extend the entire length of the second portion 22b of the housing 22. In some cases, the proximally extending portion 81b can have a length of about 0.015 inches to about 0.2 inches, about 0.015 inches to about 0.1 inches, about 0.015 inches to about 0.05 inches, about 0.03 inches to about 0.2 inches, about 0.03 inches to about 0.1 inches, or about 0.03 inches to about 0.05 inches.

[0111] Figure 4 A schematic cross-sectional view is shown along Figure 3 4-4 in FIG. 4 and extends through the second portion 22b of the housing 22, the guidewire lumen 74 of the housing 22 (e.g., as discussed in more detail below), the conductor 72, and the proximally extending portion 81b of the tail 81. The helical coil portion of the fixation member 50, the distal tip 57 of the fixation member 50, and the radially extending portion 81a of the tail 81 have been added in dashed lines. Figure 4 20 to indicate the relative locations of components of leadless pacing device 20 and to indicate that these components are not typically located along the Figure 3 For clarity, the cross-section along the line 4-4 is removed. Figure 3 It can be seen in the cross section taken along line 4-4, but Figure 4 Other components not shown.

[0112] In some instances, one or more of the radially extending portion 81 a of the tail 81 and the proximally extending portion 81 b of the tail 81 can be positioned at a circumferential position that is circumferentially aligned with the circumferential position of the distal tip 57 of the fixation member 50, or at another predetermined angular orientation that is different from the circumferential position of the distal tip 57. Such alignment of one or both of the radially extending portion 81 a and the proximally extending portion 81 b with the distal tip 57 can facilitate positioning the distal tip 57 for puncturing into myocardial tissue adjacent to the patient's coronary sinus 15 by providing variously sized radiopaque components of the leadless pacing device 20 that can be at known positions relative to the distal tip 57 and that can be seen in images of the patient.

[0113] Figure 5FIG. 2 shows a partial schematic cross-sectional view of the second portion 22b of the housing 22 and the proximal end 24a of the distal extension 24, wherein the first portion 22a of the housing 22 is not shown in the cross section. Figure 5 2, the guidewire port 54 in one side of the second portion 22b of the housing 22 is at the proximal end of a guidewire lumen 74 formed through the second portion 22b of the housing 22. The guidewire lumen 74 can extend through the second portion 22b of the housing 22 to the proximal end of a lumen 76 of the distal extension 24, wherein the lumen 76 communicates with the lumen 74. The guidewire port 54, the guidewire lumen 74, and the guidewire lumen 76 extending through the distal extension 24 can form a passage for receiving a guidewire to facilitate following the leadless pacing device 20 along the guidewire to a target location. In some cases, the leadless pacing device 20 can follow the guidewire using a rapid exchange technique, in which the wire is reversed through a distal guidewire port in the distal extension 24 (e.g., at the distal end of the distal extension 24), which communicates with the lumen 76 and passes through the lumen 76, the guidewire lumen 74, and the guidewire port 54. Other guidewire following techniques can be employed.

[0114] The guidewire lumen 74 extending through the second portion 22b of the housing 22 can be formed in any manner. In one example and when the second portion 22b can be formed by an overmolding process, a core material can be inserted into an overmold, the distal extension 24 can be positioned in the overmold so as to be aligned with the core material and extend from the overmold at an oblique angle A relative to line A, a molding material (e.g., polyurethane resin, silicon, and / or other biocompatible molding materials suitable for an overmolding process) can be applied, and once the overmolding material solidifies, the core material can be removed from the overmolding material to form a guidewire lumen 74 and a guidewire port 54 that communicate with the guidewire lumen 76 of the distal extension 24. This positioning of the guidewire port 54 and the guidewire lumen 74 in the second portion 22b of the housing 22 can facilitate hermetically sealing the components of the first portion 22a of the housing 22 within the first portion 22a and establishing an integral guidewire lumen with a smooth transition between the guidewire lumens 74 and 76.

[0115] The guide wire port 54 may be formed along any portion of the housing 22. Figure 5As shown in , the guidewire port 54 can be located between the proximal end of the second portion 22b of the housing 22 and the second electrode 28 positioned within the second portion 22b of the housing 22. In some cases, the guidewire port 54 can be formed at a side of the housing 22 that is circumferentially opposite the location of the distal end of the fixation member 50, but this is not required in all cases. This configuration of the guidewire port 54 and the distal end of the fixation member 50 relative to each other can facilitate contact between the first and second electrodes 26, 28 and the target location within the patient's body. For example, a guidewire will want to follow the maximum radius of curvature as much as possible, and because the patient's coronary sinus 15 extends around the heart 10, a guidewire inserted into the coronary sinus can naturally follow along the outer wall of the coronary sinus (e.g., the wall opposite the wall of the coronary sinus that forms the chamber wall of the heart 10) because the guidewire is able to follow a larger radius of curvature than it would otherwise be able to follow. Thus, in this example, when the guide wire port 54 is positioned on the side of the second portion 22b of the shell 22 opposite to the distal end of the fixing member 50 and the fixing member 50 extends a full circle around the second portion 22b of the shell 22, the guide wire port 54 can be adjacent to the wall of the coronary sinus 15, which is separated from the wall of the coronary sinus 15 that forms the chamber of the heart 10, so that the first and second electrodes 26, 28 can be positioned adjacent to the wall of the coronary sinus 15 (which forms the wall of the chamber of the heart 10) and can better contact the wall of the coronary sinus 15 (which forms the wall of the chamber of the heart 10) than when the guide wire port 54 is positioned elsewhere.

[0116] like Figure 5 As shown, the second portion 22b of the housing 22 can have a first diameter proximal portion 22b having a first diameter and a second diameter distal portion 22b'' having a second diameter. Although not required, in some cases, such as Figure 5As shown in , the second diameter of the second diameter portion 22b' can be less than the first diameter of the first diameter portion 22b'. In some cases, the first diameter of the proximal portion 22b' can be substantially equal to the diameter of the first portion 22a of the housing 22. Example diameters of the first diameter include, but are not limited to, diameters in the range of about 6.0 mm (0.236 inches) to about 7.0 mm (0.276 inches), diameters less than about 0.393 inches (e.g., about 30 French (Fr)) or less, and / or other suitable diameters. In one example, the first diameter can be about 6.5 mm (0.256 inches). Example diameters of the second diameter include, but are not limited to, diameters in the range of about 4 mm (0.157 inches) to about 6 mm (0.236 inches), about 4.5 mm (0.177 inches) to about 5.5 mm (0.217 inches), about 5.0 mm (0.197 inches) to about 5.2 mm (0.206 inches), diameters less than about 5.7 mm (0.226 inches) or less, and / or other suitable diameters. In one example, the first diameter can be about 6.5 mm (0.256 inches) and the second diameter can be about 5.2 mm (0.206 inches).

[0117] The fixation member 50 may extend at least partially around the outer circumference of the second portion 22b of the housing 22 and be spaced therefrom (e.g., at least partially around and spaced from the second diameter distal portion 22b'' or other suitable portion of the second portion 22b of the housing 22). In some cases, when the fixation member 50 extends at least partially around the outer circumference of the second portion 22b of the housing 22, the gap or space S may be positioned between the circumference at the inner diameter of the fixation member 50 and the outer circumference of the distal portion of the second portion 22b. Although not required, the fixation member 50 may be configured such that the space S spans a distance suitable for receiving a portion of the myocardial tissue radially between the second portion 22b of the housing 22 and the fixation member 50 when the fixation member 50 engages the myocardial tissue. Example distances that the space S may span may include, but are not limited to, a distance between about 0.001 inches and about 0.006 inches, a distance between about 0.002 inches and about 0.004 inches, or other suitable distances. In one case, the space S may span a distance of about 0.003 inches.

[0118] Figure 6 A partial schematic cross-sectional view of the second portion 22b of the housing 22 and the proximal end 24a of the distal extension 24 is shown, similar to FIG. Figure 5, but having a strain relief portion 77 extending distally from the distal end of the second portion 22 b of the housing 22 along the outer surface of the distal extension 34. When included in the leadless pacing device 20, the strain relief portion 77 can have flexibility that varies along its length and can facilitate the transition from the more rigid second portion 22 b of the housing 22 to the less rigid distal extension 24. This transition in stiffness can facilitate navigation through the tortuous vasculature of the patient.

[0119] In some cases, the strain relief portion 77 can have a taper extending distally and can extend distally a suitable distance from the second portion 22b of the housing 22. In one example, the strain relief portion 77 can extend from about 1.0 to about 4.0 centimeters (cm) from the second portion 22b of the housing 22, extend from 1.0 to 3.5 cm from the second portion 22b of the housing 22, and / or extend other suitable distances. Furthermore, in addition or alternatively to the strain relief portion 77 including a taper, the strain relief portion 77 can include a spring, one or more materials having a desired hardness or hardness gradient, and / or other mechanisms for establishing different flexibility along the length of the strain relief portion 77. In one example, the strain relief portion 77 can include one or more materials along its length, wherein the one or more materials can have different hardnesses to establish a transition in stiffness or hardness gradient along the length of the strain relief portion 77.

[0120] like Figure 6 As shown, the strain relief portion 77 can be asymmetrically positioned about the distal extension 34 to facilitate rotation of the leadless pacing device 20 including the distal extension 24. Figure 6 , but another example of an asymmetrically configured strain relief 77 may include a strain relief 77 that covers only a single half or other suitable portion of the circumference of the distal extension 24, such that the strain relief 77 surrounds less than the entire circumference of the distal extension 24 (e.g., covers a half or a portion of the distal extension 24 that is angled toward the second portion 22b of the housing 22). Alternatively, the strain relief 77 may be positioned symmetrically around the distal extension 34. In other cases, the strain relief 77 may be omitted.

[0121] The strain relief portion 77 can be formed from one or more components and / or one or more suitable materials. In one example, the strain relief portion 77 can be formed from silicone or other suitable materials. In some cases, the material used to form the strain relief portion 77 can receive a marker, such as a serial number, a company logo, and / or other suitable markers, which may or may not need to be provided on the leadless pacing device 20. Additionally or alternatively, the strain relief portion 77 can be formed while the second portion 22b of the housing 22 is formed using an overmolding process. In this case, the strain relief portion 77 can be formed as a part of the second portion 22b of the housing 22. Alternatively, the strain relief portion 77 can be formed from a component separate from the material forming the second portion 22b of the housing 22.

[0122] Figure 7-13 Various schematic diagrams of an illustrative fixation member 50 in a spiral coil configuration are shown, the spiral coil configuration exposing different portions of the spiral coil to form electrical contact with the patient's cardiac tissue. In some cases, the exposed portion of the spiral coil can be defined by coating the unexposed portion of the spiral coil (e.g., non-conductive). In some cases, the spiral coil can be formed of a conductive material, and the unexposed portion of the spiral coil can be covered with a dielectric material or other suitable insulating material. Examples of such materials include, but are not limited to, poly(p-xylene) polymers (e.g., parylene, parylene C, etc.), titanium nitride, iridium oxide (IrOx), aluminum oxide, and / or other suitable dielectric materials. In some cases, the portion of the spiral coil used to receive the coating material can be surface modified (e.g., etched, sandblasted, and / or other suitable surface modifications) to promote adhesion of the coating material to the metal forming the spiral coil of the fixation member 50. In addition, although the accompanying drawings show the material forming the fixation member 50 as a round wire with a distal end 57, the material forming the fixation member 50 can be a flat wire with a distal end and / or can have one or more other suitable structures.

[0123] In some cases, a mask may be formed on a portion of the fixing member 50 that is to be exposed (eg, as described below with reference to Figure 7-13The exposed portion 51 discussed above is disposed on the fixed member 50 to form an electrical contact with the patient's cardiac tissue (e.g., the portion of the fixed member 50 that forms the second electrode 28), so that when the fixed member 50 receives the coating material, the masked portion of the fixed member 50 is not covered by the coating material or is otherwise exposed to form the second electrode 28 on or along the fixed member 50. In some cases, the portion of the fixed member 50 that is exposed to form an electrical contact with the patient's cardiac tissue can include any suitable total area of ​​the fixed member 50. For example, the portion of the fixed member 50 that is exposed to form an electrical contact with the patient's cardiac tissue can have a total area in the range of about 0.078 inches to about 0.315 inches, in the range of about 0.137 inches to about 0.158 inches, and / or other suitable total areas of the fixed member 50.

[0124] Figure 7 is a schematic top view and Figure 8 are schematic side views showing a fixation member 50 having a distal tip 57 and an exposed portion 51 at the last quarter turn of the helical coil forming the fixation member 50, wherein the remainder of the helical coil may be an unexposed portion 53 covered in an insulating and / or dielectric material layer 55. The distal tip 57 can be formed at the distal end of the helical coil, which has been straightened to facilitate the distal tip 57 to pierce the patient's heart wall, extending along a lateral side of the implanted leadless pacing device 20. The distal tip 57 can have a sharp tip and / or edge configured to pierce and engage the patient's heart wall. Figure 7 and 8 The exposed portion 51 in the embodiment extends over the top half of the outer surface of the material forming the spiral coil. However, at the last quarter turn of the spiral coil, the exposed portion 51 may extend over a different half or other portion of the outer surface of the material forming the last quarter turn of the spiral coil, so that Figure 7 and 8 The exposed portion 51 in the figure may be rotated 90 degrees, 180 degrees, 270 degrees, and / or other appropriate amounts.

[0125] Fig. 9 is a schematic top view and Fig.10 are schematic side views showing a fixing member 50 having a distal tip 57 and an exposed portion 51 at the second to last quarter turn of the helical coil forming the fixing member 50, wherein the remainder of the helical coil may be an unexposed portion 53 covered in a layer 55 of insulating and / or dielectric material. Fig. 9 and 10The exposed portion 51 in the embodiment extends on the inner half of the outer surface of the material forming the spiral coil. However, at the second to last quarter turn of the spiral coil, the exposed portion 51 may extend on a different half or other portion of the outer surface of the material forming the second to last quarter turn of the spiral coil, so that Fig. 9 and 10 The exposed portion 51 in the figure may be rotated 90 degrees, 180 degrees, 270 degrees, and / or other appropriate amounts.

[0126] Fig.11 is a schematic side view showing a fixation member 50 having a distal tip 57 and an exposed portion 51 at the distal tip 57 of the fixation member 50. Fig.11 In the embodiment, all portions of the helical coil forming the fixation member 50 except for the distal tip 57 may be an unexposed portion 53 of the fixation member 50 , which is covered with a layer 55 of an insulating and / or dielectric material.

[0127] Fig.12 is a schematic top view showing a fixation member 50 having a distal tip 57 and having an exposed portion 51 defined by an angle B, wherein the angle B may extend from the distal tip 57 of the fixation member 50 (e.g., as Fig.12 , where angle B extends from a possible radial position of the distal end 57 if the material of the helical coil forming the fixation member 50 is not straightened) to a position proximal to the distal end 57. Angle B can have any suitable value. In some cases, angle B can be in a range of, for example, about 5 to 45 degrees, about 5 to 60 degrees, about 5 to 90 degrees, about 5 to 180 degrees, or about 5 to 360 degrees. In some cases, angle B can be determined at least in part based on the desired size of the exposed portion 51 and / or the desired size of the unexposed portion 53 covered with the insulating and / or dielectric material layer 55. Although angle B is shown as having one end at the distal end 57, this is not required and angle B can extend between any two radial sections along the helical coil forming the fixation member 50. In addition, Fig.12 The exposed portion 51 in the angle B may extend over the top half of the outer surface of the material forming the helical coil. However, the exposed portion 51 of the helical coil at angle B may extend over a different half or other portion of the outer surface of the material forming the helical coil at angle B, such that Fig.12 The exposed portion 51 in the figure may be rotated 90 degrees, 180 degrees, 270 degrees, and / or other appropriate amounts.

[0128] Fig.13is a schematic top view showing a fixation member 50 having a distal tip 57 and having exposed portions 51 at different intervals defined by angles C and D, wherein angle C can define the width of the exposed portion and angle D can define the width of an unexposed portion 53 covered by a layer of insulating and / or dielectric material 55. Angle C and angle D can have any suitable values, including but not limited to the same value or different values. In some cases, angle C and / or angle D can be in a range of approximately 2 to 10 degrees, approximately 2 to 30 degrees, approximately 2 to 45 degrees, approximately 5 to 10 degrees, approximately 10 to 30 degrees, or approximately 10 to 45 degrees. In some cases, angle C can be determined at least in part based on a desired size of the exposed portion 51, and angle D can be determined at least in part based on a desired size of the unexposed portion 53. Fig.13 In the embodiment, the exposed portions 51 and the unexposed portions 53 alternate throughout the turns of the helical coil forming the fixing member 50, but may alternate at any other suitable radial distance around the helical coil. Fig.13 The exposed portion 51 in the helical coil may extend over the top half of the outer surface of the material forming the helical coil. However, the exposed portion 51 of the helical coil may extend over a different half or other portion of the outer surface of the material forming the exposed portion 51 of the helical coil defined by the angle C, such that Fig.13 The exposed portion 51 in the figure may be rotated 90 degrees, 180 degrees, 270 degrees, and / or other appropriate amounts.

[0129] Fig.14 1 is a schematic partial cross-sectional view of the right atrium 11, the left atrium 12, and the coronary sinus 15, wherein the leadless pacing device 20 is inserted into the coronary sinus 15, which is at least partially defined by a portion 82 of a wall defining the coronary sinus 15 (which is spaced apart from a wall defining the atria of the heart 10), a wall 84 of the left atrium 12, and a wall 85 of the right atrium 11. In one example, as Fig.14 As shown, the fixation member 50 can engage tissue forming the wall 84 of the left atrium 12 so that the leadless pacing device 20 is in good electrical contact with a wall defining at least one chamber of the heart 10. In this example, when the fixation member 50 engages the wall 84 forming the left atrium 12, the second electrode 28 that can be supported or formed by the fixation member 50 can be in good electrical contact with the tissue forming the wall 84 of the left atrium 12 because the fixation member 50 is inserted into such tissue, and the first electrode 26 that can be supported or formed by the first portion 22a of the housing 22 can be in good electrical contact with tissue forming the wall 85 of the right atrium 11 because the fixation member 50 engages the tissue of the heart 10. In addition, when the fixation member 50 engages the tissue of the heart 10, the distal extension 24 can be inserted into a blood vessel extending from the coronary sinus 15.

[0130] Fig.15A and 15B A schematic end view of a leadless pacing device 20 positioned within the coronary sinus 15 of the heart 10 is shown, wherein the leadless pacing device 20 is viewed from a distal end view, and the heart 10 and the coronary sinus 15 are located in cross-section. Although the walls defining the coronary sinus 15 are shown in cross-section, for purposes of clarity, the walls defining the coronary sinus 15 are not shown in shading. Fig.15A The leadless pacing device 20 is schematically illustrated within the coronary sinus 15 before the fixation member 50 engages the wall 84 defining the left atrium 12. Additionally, at a location where the fixation member 50 extends from the second portion 22b of the housing 22, the second portion 22b of the housing 22 can define a stop 23 configured to limit insertion of the fixation member 50 into the tissue to a predetermined insertion amount (e.g., to limit rotation of the leadless pacing device 20 when the fixation member 50 engages the tissue). The predetermined insertion amount can be substantially equal to the length of the fixation member 50 extending from the stop 23 to the distal end of the fixation member 50. Although the stop 23 is not substantially equal to the length of the fixation member 50 extending from the stop 23 to the distal end of the fixation member 50, the stop 23 can be substantially equal to the length of the fixation member 50 extending from the stop 23 to the distal end of the fixation member 50. Fig.15A and 15B The stopper 23 is shown as being formed by the housing 22 (e.g., a molded portion forming the second portion 22b of the housing 22), but the stopper 23 can be formed by a change in the diameter or coil of the fixation member 50, and / or be constructed from one or more other suitable components. In some cases, the stopper 23 can be or can be formed without a gradually inclined shoulder, so that if the leadless pacing device 20 is rotated beyond a predetermined amount, the stopper 23 prevents gradual entry and tearing or rupture of the wall of the heart 10. In one example, the stopper 23 can be formed by the second portion 22b of the housing 22 or the fixation member 50 and form a generally flat surface, which can be generally perpendicular to the central axis, which extends through the material (e.g., wire material) forming the helical coil of the fixation member 50. However, in other cases, the stopper 23 can have a taper or gradually expanding width. In addition, although it can be seen that the fixing member 50 extends a full circle from the second portion 22b of the shell 22 and the stop 23, so that the predetermined rotation amount can be a full circle of the leadless pacemaker 20, as needed, more or less of the fixing member 50 can be exposed from the second portion 22b of the shell 22, so that the predetermined rotation amount can be correspondingly greater than or less than a full circle.

[0131] As viewed from the distal end of the leadless pacing device 20, the helical fixation member 50 can helically extend in a counterclockwise direction to the distal tip 57. Thus, with the distal tip 57 of the fixation member 50 pointing toward the upper portion of the coronary sinus, counterclockwise rotation of the leadless pacing device, as viewed from the distal end of the housing 22 along the axis of the housing 22 toward the proximal end of the housing 22, will cause the distal tip 57 to engage the luminal surface of the coronary sinus 15 and puncture into cardiac tissue (e.g., left atrial muscle).

[0132] In addition, if Fig.15A As shown, the distal tip 57 can extend radially beyond the outer diameter of the housing 22 to facilitate engagement of the distal tip 57 with heart tissue.

[0133] Fig. 15B A leadless pacing device 20 is shown positioned in the coronary sinus 15 and relative to Fig.15A 84. The radial position of the leadless pacing device 20 shown in FIG. 84 is approximately one full rotation. As the leadless pacing device 20 rotates and the fixation member 50 engages the wall 84, the stop 23 can engage the wall 84 at an entry point adjacent to the fixation member 50 to limit and / or prevent continued rotational movement of the leadless pacing device 20. In addition, as the fixation member 50 engages tissue of the wall 84, a portion of the wall 84 can be squeezed or otherwise positioned between the fixation member 50 and a portion of the second portion 22 b of the housing 22 around which the fixation member extends when the fixation member 50 does not engage the wall of the patient's heart 10.

[0134] Fig.16 and 17 A schematic partial side view of a leadless pacing device 20 is shown illustrating the second portion 22b of the housing 22, the proximal end 24a of the distal extension 24, and a communication line 79 that communicates with a conductor electrically connected to an electronic module within the first portion 22a of the housing 22. The communication line 79 may be shown in phantom to indicate that the line may be embedded within the material forming the second portion 22b of the housing 22. The communication line 79 may be any suitable type of communication line. In one example, the communication line 79 may be an inductive communication antenna. The communication line 79 may facilitate communication with one or more other electronic devices via a wireless protocol including, but not limited to, radio frequency (RF), near field communication (NFC), Bluetooth, Bluetooth low energy (BLE), and / or other suitable wireless protocols. Furthermore, although in Fig.16 and 17 Only a single communication line 79 is shown in FIG. 1 , but more than a single communication line 79 may be used to facilitate communications via one or more communication protocols, or no communication line may be provided.

[0135] like Fig.16As shown, the communication line 79 can be wrapped around and / or within the second portion 22b of the housing 22. When the communication line 79 is supported by the second portion 22b of the housing 22, the communication line 79 can be at least partially embedded in the housing 22 during a forming process (e.g., an overmolding process or other suitable forming process) of forming the second portion 22b of the housing 22. Alternatively or additionally, the communication line 79 can be positioned at and / or fastened in the second portion 22b of the housing 22 in one or more other suitable ways.

[0136] like Fig.17 As shown, when the strain relief portion 77 is included in the leadless pacing device 20, the communication line 79 can extend within the strain relief portion 77 around the distal extension 24. When the communication line 79 is supported by the strain relief portion 77, the communication line 79 can be at least partially embedded in the strain relief portion 77 during a forming process (e.g., an overmolding process or other suitable forming process) of forming the strain relief portion 77 around the distal extension 24. Alternatively or additionally, the communication line 79 can be wrapped around the proximal end 24a (e.g., by wrapping the proximal end 24a at the Fig.17 At least a portion of the distal extension 24 is shown as a dashed line, indicating that such a portion may be covered by the strain relief portion 77), and then the strain relief portion 77 may be applied thereto to protect the communication line 79. When the communication line 79 is embedded in the strain relief portion 77 or otherwise located within the strain relief portion, the communication line 79 may act as a reinforcement in the strain relief portion 77, and when the communication line 79 is wrapped around the proximal end 24a of the distal extension 24, the communication line 79 acts as a reinforcement for the distal extension. In addition, the communication line 79 may be positioned at the strain relief portion 77 and / or the distal extension 24 in one or more other suitable manners, and / or fastened in the strain relief portion 77 and / or the distal extension 24.

[0137] In some cases, the leadless pacing device 20 can include a drug eluting component or feature configured to release one or more drugs over time. The sustained-release drug can be any suitable drug, including but not limited to drugs suitable for blocking cell proliferation to prevent fibrosis, drugs suitable for promoting cell proliferation, and / or other suitable drugs. An example of a drug eluting component or feature can include but is not limited to a drug collar configured to elute a drug suitable for blocking cell proliferation so as to prevent fibrosis. An example of a drug to be eluted is dexamethasone acetate and / or other similar or different suitable drugs. Figure 18-21 Various schematic diagrams of the leadless pacing device 20 are shown including a drug loop 89. Alternatively or additionally, the drug eluting component or feature can employ one or more other suitable configurations, including, but not limited to, an adhesive that is mixed with the drug to be eluted, applied to a portion of the leadless pacing device 20, and cured.

[0138] Fig.18 A schematic perspective view of a leadless pacing device 20 having a drug collar 89 extending around a second portion 22b of the housing 22 is shown. In some cases, the drug collar 89 can be configured on the second portion 22b of the housing 22 such that the fixation member 50 extends from the stop 23 of the second portion 22b of the housing 22 and extends at least partially around the drug collar 89. When the drug collar 89 is so positioned, the fixation member 50 can be configured to capture tissue from the patient's heart wall between the fixation member 50 and the drug collar 89. In some cases, when the leadless pacing device 20 is implanted, the drug collar can be configured to prevent or reduce cell growth at or around the fixation member 50 and / or housing 22. In one example, the drug collar 89 can be configured on the leadless pacing device 20 so as to be adjacent to a site of trauma when the fixation member 50 enters the patient's heart tissue (e.g., the drug collar 89 can be configured on the housing 22 so as to be adjacent to a puncture point on the patient's heart wall caused by the fixation member 50 entering the heart wall).

[0139] In some cases, drug collar 89 may be formed as a single-piece ring, such as Fig.18 Alternatively, the drug collar may be formed from one or more portions that are adjacent to each other or spaced apart from each other.

[0140] Fig.19 2 is a schematic side view of a leadless pacing device 20 having a drug collar 89 extending around a second portion 22 b of a housing 22, as shown in FIG. Fig.19 , wherein the drug collar 89 and the second portion 22b of the housing 22 (about which the drug collar 89 is positioned) are shown in cross-section. Fig.19 As shown, the drug collar 89 may be coupled to the second portion 22b of the housing 22 by a medical grade adhesive applied to one or more sides of the drug collar 89 facing the second portion 22b of the housing 22, and / or one or more sides of the second portion 22b of the housing 22 facing the drug collar 89. One or more suitable medical grade adhesives may be used as desired, including but not limited to medical grade silicone.

[0141] Fig. 20 2 is a schematic side view of a leadless pacing device 20 having a drug loop 89 extending around a second portion 22 b of a housing 22, wherein the drug loop 89 and the second portion 22 b of the housing 22 (around which the drug loop 89 is positioned) are shown in cross-section. Fig. 20As shown, the drug collar 89 can be coupled to the second portion 22b of the housing 22 by positioning and / or applying a coupling material interface 91 between one or more sides of the drug collar 89 and one or more sides of the second portion 22b of the housing 22. In some cases, the coupling material interface 91 can be L-shaped, but this is not required. The coupling material interface 91 can be composed of one or more suitable materials, including but not limited to polyetheretherketone (PEEK).

[0142] Although Fig.19 and 20 Accordingly, the drug collar 89 is shown coupled to the housing 22 using an adhesive and a coupling material interface, but other techniques for coupling the drug collar 89 to the housing 22 are also contemplated. In one example, the drug collar 89 may be coupled to the housing 22 during the formation of the second portion 22b of the housing 22 using an overmolding process by positioning the drug collar 89 at a desired location when the molding material forming the second portion 22b is cured. Other techniques for coupling the drug collar 89 to the housing 22 are also contemplated.

[0143] Fig.21 is a schematic side view of a leadless pacing device 20 having a strain relief 77 and a drug loop 89 extending around the strain relief 77, wherein the drug loop 89 is shown in cross-section. Although not required, the strain relief 77 can include a recess 102 or other suitable features for receiving the drug loop 89. In some cases, the recess 102 can extend completely or at least partially around the strain relief 77, and can be sized so that the drug loop 89 received in the recess 102 can be flush with the outer surface of the strain relief. Other configurations of the recess 102 or other suitable features for receiving the drug loop 89 are contemplated. The drug loop 89 can be coupled to the strain relief 77 by a medical grade adhesive applied to one or more sides of the drug loop 89 facing the strain relief 77, and / or one or more sides of the strain relief 77 facing the drug loop 89. One or more suitable medical grade adhesives can be used as desired, including but not limited to medical grade silicone. As desired, drug collar 89 may be coupled to and / or constructed about strain relief 77 in one or more other suitable manners.

[0144] Fig. 22 2 is a schematic side view of a leadless pacing device 20, in which the second portion 22b of the housing 22 can be constructed of a first sub-portion 93 (e.g., a first head portion) and a second sub-portion 95 (e.g., a second head portion). The first sub-portion 93 can be directly connected to or directly connected to the second sub-portion 95, and / or a third sub-portion 101 can be employed to facilitate connecting the first sub-portion 93 to the second sub-portion 95.

[0145] The first subsection 93 may include conductors 70 and 72 extending from the first portion 22a of the housing 22, such as Fig. 22 , and / or one or more other suitable components or features. In addition to other features, the second subsection 95 may include a guidewire port 54, a guidewire lumen 74 of the second portion 22b of the housing 22, a distal extension 24, at least a portion of a guidewire lumen 76 of the distal extension 24, a fixation member 50 (e.g., forming a second electrode 28 and having a distal tip 57) Fig. 22 As shown), and / or one or more other suitable components or features. Alternatively or additionally, one or more components or features of the first subsection 93 or the second subsection 95 can be positioned within the other of the first subsection 93 or the second subsection 95.

[0146] One or both of the first subsection 93 and the second subsection 95 may be preformed and may be configured to engage and couple with each other. In some cases, the first subsection 93 may be formed on the first portion 22a of the housing 22 (e.g., via an overmolding process or other suitable technique), or supported by and / or coupled to the first portion of the housing, and may include a first connector 97 configured to engage (e.g., mechanically and / or electrically) the second subsection 95.

[0147] The second subsection 95 may be formed via an overmolding process or other suitable technique and may include a second connector 99 configured to engage (e.g., mechanically and / or electrically) the first connector 97 so as to be supported by the first subsection 93. The first connector 97 and the second connector 99 are schematically shown in Fig. 22 In some cases, one of the first connector 97 and the second connector 99 can be a female connector, and the other of the first connector 97 and the second connector 99 can be a male connector configured to be received by the first connector to establish a plug-in mechanical and / or electrical connection between the first subsection 93 and the second subsection 95.

[0148] To facilitate permanent engagement between the first connector 97 and the second connector 99, the first connector 97 and the second connector 99 may be welded or otherwise bonded to one another. Alternatively or additionally, one or more other suitable portions of the first subsection 93 and the second subsection 95 may be welded or otherwise bonded to one another to facilitate establishing a permanent connection between the first subsection 93 and the second subsection 95.

[0149] When included, the third subsection 101 can be configured to couple (e.g., mechanically and / or electrically) the first subsection 93 and the second subsection 95 in a permanent or non-permanent manner. In one example, the third subsection 101 can be molded on and / or otherwise receive or extend around the first and second connectors 97 and 99, wherein the first and second connectors 97 and 99 are spaced apart from each other. Alternatively or additionally, the third subsection 101 can be molded on and / or otherwise receive or extend around the first and second connectors 97 and 99, wherein the first and second connectors 97 and 99 can be pre-connected to each other (e.g., connected before applying the third subsection 101). In addition, the third subsection 101 can include an electrical connector and, when pre-formed, can act as a female or male plug configured to connect with the first and second connectors 97 and 99 to establish a mechanical and / or electrical connection between the first subsection 93 and the second subsection 95.

[0150] When included, the third subsection 101 can be formed via an overmolding process or other appropriate technique. In some cases, the third subsection 101 can be a preformed component constructed from a suitable biocompatible metal and / or polymer material. The third subsection 101, whether overmolded, preformed, or formed by one or more other appropriate techniques, can include one or more electrical connectors configured to connect electrical components of the first subsection 93 (or in communication with the first subsection 93) to electrical components of the second subsection 95 (or in communication with the second subsection).

[0151] When the first subsection 93 and the second subsection 95 are coupled to each other (e.g., directly and / or through the third subsection 101), the electrical components of the subsection 93 can be electrically coupled to the second subsection 95. In one example, the conductors 70, 72 and / or other conductors of the first subsection 93 can be connected to wires and / or other conductive components carried or supported by the second subsection 95 via plug connections (not shown) and / or other suitable connection methods, which are engaged when the first subsection 93 and the second subsection 95 are mechanically coupled. Other types of electrical, mechanical and / or electromechanical connections can be made to facilitate electrically connecting the first subsection 93 of the second portion 22b of the housing 22 and / or the electrical components of the first portion 22a of the housing 22 to the second subsection 05 of the second portion 22b of the housing 22.

[0152] Figure 23-31An exemplary use (e.g., implantation and removal) of a leadless pacing device 20 within the heart 10 is shown. Although the illustrated method includes gaining access to the patient's heart 10 through the inferior vena cava, access to the heart 10 may additionally or alternatively be gained through the superior vena cava and / or other approaches. Figure 23-31 The view of the heart 10 is similar to Figure 1 The view shown in .

[0153] Figure 23-31 The dashed lines shown in the figure illustrate some features that may be covered by one or more other features and are generally not visible from the view shown. The features in dashed lines are shown to assist in describing the disclosed concepts. In addition, for clarity, features within the coronary sinus 15 are shown in solid lines, even though these features are generally not visible from the view shown.

[0154] In some embodiments, the leadless pacing device 20 can be implanted in the heart 10 by inserting a guide wire (e.g., Fig.23 The first guidewire 94 may have a diameter of 0.035 inches and / or one or more other suitable diameters to provide access to the heart 10. The first guidewire 94 may be provided through an opening in the patient's skin that extends into an artery or vein (e.g., a femoral vein or other blood vessel) that has been dilated by an introducer or other device having a dilation feature (e.g., using a Fig.24 8 and catheter 80 are shown, and a first guidewire 94 is advanced to reach and / or through the inferior vena cava or other body vessels.

[0155] In some cases, the first guide wire 94 can have one or more radiopaque markers disposed on an end of the first guide wire 94. Such radiopaque markers can allow the first guide wire 94 to be more easily observed by one or more medical imaging systems when the first guide wire 94 is manipulated into position with respect to the heart 10. In some embodiments, the radiopaque markers can be spaced a known distance from one another. In such embodiments, by counting the number of radiopaque markers between two features within the heart 10, the distance between the two features can be determined. In some embodiments, the leadless pacing device 20 can be manufactured in various sizes, or various portions of the leadless pacing device 20, such as the housing 22 and the distal extension 24, can be manufactured in various sizes and lengths. By determining the distances between different features of the patient's heart 10, such as the distance between the coronary sinus ostium 16 and the septum 18 in the right atrium 11, Fig.23 As shown in FIG. 1 , an appropriately sized housing 22 or distal extension 24 may be selected for a particular patient.

[0156] After measuring the distances between various features of the heart 10, or in embodiments where such measurements are not required, the catheter 80 (e.g., introducer) and dilator 86 may be manipulated into the heart 10 over the first guidewire 94, as shown. Fig.24 As shown. In some cases, the catheter 80 can be steerable, and the dilator 86 can be positioned at or near the distal end of the catheter 80 (e.g., at or near the distal tip). The dilator 86 can be configured to engage the ostium 16 of the coronary sinus 15, and dilate and / or insert into the coronary sinus 15 so that the catheter 80 and / or the leadless pacing device 20 can be received therein. Alternatively or additionally, the catheter 80 can have a preformed bend at or near the distal end of the catheter 80. In this case, the dilator 86 can be inserted through the distal end of the catheter 80 to straighten the distal end of the catheter 80 during insertion of the catheter into the heart 10. Then, when the distal end of the catheter 80 is within the heart, such as within the right atrium 11, the dilator 86 can be withdrawn, so that the distal end of the catheter 80 is bent so as to face and / or extend into the coronary sinus 15, and guide the first guide wire 94 toward and / or into the coronary sinus 15.

[0157] Fig.25 The catheter 80 and the first guide wire 94 are shown, which are bent and inserted into the coronary sinus 15 after the dilator 86 is withdrawn through the catheter 80. In some cases, after the catheter 80 is bent toward the coronary sinus 15, the first guide wire 94 can be advanced into the coronary sinus, and the catheter 80 can be advanced along the first guide wire 94 and into the coronary sinus 15.

[0158] The dilator 86 can be configured with a conical tapered tip such that advancing the catheter 80 and dilator 86 into the coronary sinus 15 expands the inner diameter of the coronary sinus 15. In another example, the dilator 86 can be rounded, or can have a more abrupt taper than a conical taper. Other dilator configurations are contemplated, and any configuration suitable for dilating the coronary sinus 15 can be employed. Thus, if it is necessary for the coronary sinus 15 to be dilated to receive the leadless pacing device 20, the dilator 86 and / or the distal end or distal tip of the catheter 80 can be advanced through the ostium 16 of the coronary sinus 15 to dilate the coronary sinus 15 an amount sufficient to receive the leadless pacing device 20. In addition and or alternatively to the catheter 80 and / or dilator 86, one or more other catheters, dilators, or introducers can be used to facilitate dilation, insertion, and / or otherwise access to the coronary sinus 15.

[0159] Fig.25The catheter 80 and the first guide wire 94 are shown, which are bent and inserted into the coronary sinus 15 after the dilator 86 is withdrawn through the catheter 80. In some cases, after the catheter 80 is bent toward the coronary sinus 15, the first guide wire 94 can be advanced into the coronary sinus, and the catheter 80 can be advanced along the first guide wire 94 and into the coronary sinus 15.

[0160] Once the coronary sinus 15 has been cannulated and the catheter 80 inserted therein, the first guide wire 94 may then be removed from the catheter 80, as shown. Fig.26 In some cases, a second guide wire 96 may be inserted into the catheter 80 and manipulated all the way through the coronary sinus 15 and into the great cardiac vein 17 or other blood vessels extending from the coronary sinus 15, such as Fig. 27 Second guidewire 96 may have a diameter of approximately 0.014 inches and / or other suitable diameters for traveling through blood vessels of heart 10 and / or blood vessels extending around heart 10 (e.g., for traveling through great cardiac vein 17 and / or other blood vessels extending from or to great cardiac vein 17).

[0161] Fig.28 The leadless pacing device 20 and catheter 80 are shown positioned within a delivery / retrieval catheter 88 within the coronary sinus 15, with the distal extension 24 following over a second guidewire 96 into the great cardiac vein or other cardiac vessel. The second guidewire 96 can exit a guidewire port of the housing 22 and extend along an exterior of the proximal portion 22a of the housing 22. The first portion 22a of the housing 22 of the leadless pacing device 20 and the proximal member 38 can be extended proximally out of the coronary sinus 15 into the right atrium 11 via an interlock mechanism 100 and a positioning device 98 connected to the proximal member 38. The leadless pacing device 20 can be advanced to this position by pushing the leadless pacing device 20 and the delivery / retrieval catheter 88 with the positioning device 98 over the second guidewire 96 and through the catheter 80 while the interlock mechanism 100 is connected to the proximal member 38. Alternatively, only one of the catheter 80 or the second guidewire 96 can be employed to position the leadless pacing device 20 and the delivery / retrieval catheter 88. Moreover, it is conceivable that the leadless pacing device 20 can be positioned with neither the catheter 80 nor the second guide wire 96. In some cases, the interlock mechanism 100 can be connected to or can engage the proximal member 38 until it is positively or intentionally released or disconnected via interaction with the proximal end of the positioning device 98.

[0162] Once the leadless pacing device 20, delivery / retrieval catheter 88, and catheter 80 have been positioned within the coronary sinus 15 proximal to the target location, the leadless pacing device 20 within the delivery / retrieval catheter 88 can be rotated to position the distal tip 57 of the fixation member 50 at a desired location for piercing and engaging the patient's cardiac tissue forming the wall of the chamber (e.g., at a position similar to Fig.15A The orientation of the leadless pacing device 20 within the coronary sinus 15 and / or within the delivery / retrieval catheter 88 can be adjusted via interaction with the proximal end of the positioning device 98, and / or can be adjusted in different suitable ways. In some cases, the orientation of the leadless pacing device 20 within the coronary sinus 15 and / or within the delivery / retrieval catheter 88 can be adjusted by adjusting the position of the leadless pacing device 20 in the longitudinal direction and / or by rotating the leadless pacing device 20 in the direction of arrow A and / or arrow B using the positioning device 98.

[0163] In some cases, the rotational position and / or longitudinal position of the distal tip 57 may be known or identifiable from one or more radiopaque markers, and the known rotational position and / or longitudinal position may be employed to locate the distal tip 57. In one example, the distal tip 57 may be or may include a radiopaque marker that is identifiable on one or more imaging systems to facilitate proper alignment of the distal tip 57 of the fixation member 50. Alternatively or additionally, the fixation member 50 may include one or more other radiopaque features (e.g., the tail 81 and / or other suitable radiopaque features), and / or the leadless pacing device 20 may include one or more radiopaque markers having a known relationship to the distal tip 57, which may be used to locate the distal tip 57 at a desired position. In one example, the distal tip 57 may have a first circumferential position, and the tail 81 of the fixation member 50 may have a second circumferential position oriented at a predetermined angle to the first circumferential position, which may be used to facilitate rotational alignment of the distal tip 57 with target tissue of the heart. While the distal tip 57 remains within the lumen of the delivery / retrieval catheter 88 to prevent the distal tip from inadvertently puncturing tissue, a rotation of the leadless pacing device 20 can be performed to rotationally align the distal tip 57 with the target tissue of the heart, and thereafter the fixation member 50 can be deployed out of the distal end of the delivery / retrieval catheter. Alternatively or additionally, after the distal tip of the fixation member 50 is deployed out of the distal end of the delivery / retrieval catheter, the leadless pacing device 20 can be rotated in the opposite direction of the helical anchor of the fixation member to prevent the distal tip from inadvertently puncturing tissue.

[0164] Once the leadless pacing device 20 is in place, the catheter 80 and the second guide wire 96 can be retracted and the leadless pacing device 20 can be further rotated using the positioning device 98 (e.g., in the direction of arrow A and / or other appropriate directions) so that the distal tip 57 and the fixation member 50 engage tissue forming a wall of a chamber of the heart 10 (e.g., in a manner similar to Fig. 15B In some cases, the leadless pacing device 20 can be oriented so that the distal tip 57 initially punctures the left atrial muscle. Once the fixation member 50 engages the tissue forming the wall of the heart 10, the positioning device 98 and the delivery / removal catheter 88 can be retracted and, optionally, removed from the heart 10. Fig.29 An example of how the leadless pacing device 20 may be positioned is shown after the positioning device 98, the delivery / retrieval catheter 88, the catheter 80, and the second guide wire 96 have been retracted and the fixation member 50 has engaged tissue forming the wall of the heart 10. Although the housing 22 of the leadless pacing device 20 is shown extending along the right atrium 11 and the left atrium 12 in the coronary sinus 15, the housing 22 of the leadless pacing device 20 may be positioned completely along the right atrium 11 or completely along the left atrium 12 within the coronary sinus 15. In some instances, the housing 22 of the leadless pacing device 20 may be positioned along both the right atrium 11 and the left atrium 12 such that at least a portion of the first electrode 26 is in contact with tissue of the right atrium 11 and at least a portion of the second electrode 28 is in contact with tissue of the left atrium 12. In this case, the leadless pacing device 20 can be programmed to sense and / or pace one or more of the right atrium 11 and the left atrium 12 with the corresponding electrodes 26, 28 or other electrodes because the electrodes are bipolar.

[0165] In some instances, the implanted leadless pacing device 20 can be removed from the coronary sinus 15 and / or the positioning of the implanted leadless pacing device 20 can be adjusted. Fig.30 A delivery / retrieval catheter 88 and a retrieval device 78 (e.g., a positioning device, which may or may not be the positioning device 98 or may or may not be similar to the positioning device 98) are shown inserted into the coronary sinus 15, wherein the retrieval device 78 engages the proximal member 38 of the leadless pacing device 20 via an interlocking mechanism (e.g., an interlocking mechanism similar to the interlocking mechanism 100 and / or other suitable interlocking mechanisms). Once the retrieval device 78 has engaged the proximal member 38 of the leadless pacing device 20, the retrieval device 78 can apply a force to the leadless pacing device to rotate the leadless pacing device in the direction of arrow B or other suitable direction. The rotation of the leadless pacing device 20 can cause the fixation member 50 to be at least partially withdrawn from engagement with tissue forming a wall of a chamber of the heart 10.

[0166] Additionally or alternatively to rotating the leadless pacing device 20 in the direction of arrow B, a force can be applied to the leadless pacing device 20 in the direction of arrow C (e.g., in the longitudinal direction). While the fixation member 50 is still engaged with tissue of the heart, applying a force to the leadless pacing device 20 in the longitudinal direction of arrow C can cause the fixation member 50 to elongate (e.g., straighten and / or elongate in one or more other suitable manners), such as Fig.30 1 and can facilitate removal of fixation member 50 from tissue of heart 10. Depending on the material construction employed, an axial force in the range of about 0.1-1.0 lbf, in the range of about 0.1-0.5 lbf, at least about 0.25 lbf, at least about 0.50 lbf, at least about 0.25 lbf but less than about 1.0 lbf, and / or other suitable forces can be employed to elongate fixation member 50. In some cases, by applying an axial force in the direction of arrow C, fixation member 50 can be plastically deformed into a straightened configuration for removal from tissue.

[0167] After the fixation member 50 has been completely removed from the tissue of the heart 10, as shown in FIG. Fig.31 As shown, via relative movement of the retrieval device 78 and the delivery / retrieval catheter 88, the delivery / retrieval catheter 88 can be advanced over a portion or all of the leadless pacing device 20. Once covered by the delivery / retrieval catheter 88, the leadless pacing device 20 can be completely withdrawn from the coronary sinus 15 and the patient's heart 10 by applying further force in direction C, and / or repositioned within the coronary sinus 15 and / or a vessel in communication with the coronary sinus 15 by applying a rotational force in direction A to reengage the fixation member 50 with myocardial tissue adjacent to the coronary sinus 15 (e.g., to improve positioning of electrodes of the leadless pacing device 20 and / or for one or more other appropriate reasons).

[0168] In some cases, an introducer sheath (e.g., catheter 80 or other suitable sheath) can be inserted into the patient's vasculature (e.g., in the coronary sinus 15) and positioned over the leadless pacing device 20 and / or at least a portion of a delivery / retrieval catheter to facilitate withdrawal of the leadless pacing device 20 from the coronary sinus 15. In such cases, the introducer sheath can be positioned at a location covering the proximal end of the leadless pacing device 20, and the delivery / retrieval catheter 80 and / or retrieval device 78 can be advanced through the introducer sheath to the leadless pacing device 20 at least partially covered by the introducer sheath. Positioning of the introducer sheath over the proximal end of the leadless pacing device 20 can include deflecting a distal end portion of the introducer sheath into the coronary sinus 15 and guiding the introducer sheath over the proximal end of the leadless pacing device 20. Deflection and guidance of the introducer sheath may be achieved by manipulating one or more control features adjacent the proximal end of the introducer sheath, and / or the introducer sheath may have a pre-formed curve configured to bend toward the coronary sinus 15 .

[0169] It will be appreciated by those skilled in the art that the present disclosure may be embodied in various forms in addition to the specific embodiments described and contemplated herein. For example, as described herein, various embodiments include one or more modules described as performing various functions. However, other embodiments may include additional modules that separate the described functions into more modules than the modules described herein. Additionally, other embodiments may integrate the described functions into fewer modules.

[0170] Although various features may have been described with respect to less than all embodiments, the present disclosure contemplates that those features may be included on any embodiment. Furthermore, although the embodiments described herein may omit some combinations of various described features, the present disclosure contemplates embodiments that include any combination of each described feature. Therefore, deviations may occur in form and detail without departing from the scope and spirit of the present disclosure as described in the appended claims.

Claims

1. A leadless pacing device for delivering electrical stimulation to a patient's heart, the leadless pacing device comprising: A housing having a central longitudinal axis, the housing comprising: The body part; and a head extending distally from the body portion; a securing member extending from the head; a distal extension connected to the head and extending distally of a distal end of the head; and The fixation member has a helical configuration in a relaxed state and is configured to elongate to a straightened configuration in response to an axial force applied thereto.

2. The leadless pacing device of claim 1, wherein: The fixation member is configured to extend to the straightened configuration in response to an axial force applied thereto in the range of 0.1 lbf to 1.0 lbf.

3. The leadless pacing device according to claim 1 or 2, wherein: The fixation member plastically deforms to the straightened configuration in response to the axial force.

4. The leadless pacing device according to claim 1 or 2, wherein: The fixing member is formed of a platinum-iridium material.

5. The leadless pacing device according to claim 1 or 2, wherein: The securing member extends at least partially around an exterior surface of the head.

6. The leadless pacing device of claim 5, further comprising: A drug collar is positioned at least partially around the head.

7. The leadless pacing device of claim 6, wherein: The drug collar is at least partially positioned between the securing member and an exterior surface of the head.

8. The leadless pacing device according to claim 6 or 7, wherein: The drug collar is secured to the head by one or both of a medical grade adhesive and an interface comprising polyetheretherketone.

9. The leadless pacing device according to claim 1 or 2, wherein: The head extends distally of the distal end of the fixation member.

10. The leadless pacing device of claim 9, wherein: The fixation member includes a helical anchor extending to the distal tip.

11. The leadless pacing device of claim 1 , wherein: The fixing member comprises: a proximal portion embedded within the proximal portion of the head; a helical coil portion surrounding and spaced radially outwardly from an outer surface of a distal portion of the head; and a distal tip forming a terminal end of the fixation member; Wherein the distal tip is positioned proximal to the distal end of the head.

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