Delivery systems and methods for left ventricular pacing

Abstract

A method for delivering a pacing lead may include positioning a potential implantation site adjacent to or within a Koch's triangle region of a patient's heart. The method may include advancing a pacing lead to the potential implantation site. The pacing lead has an elongated body and a fixation element coupled to a distal portion and attachable to a right atrial endocardium adjacent to or within the Koch's triangle region. The method may include implanting the pacing lead at the potential implantation site in a basal and / or septal region of the left ventricular myocardium of the patient's heart to reach the left ventricle or sense electrical activity of the left ventricle. The pacing lead may include a lumen configured to receive a guidewire. A sheath of a delivery system for delivering the pacing lead may include two or more bends to facilitate implantation of the pacing lead at the implantation site.

Description

[0001] This application claims the benefit of U.S. Provisional Application Serial No. 62 / 783,479, filed on December 21, 2018, which is incorporated by reference in its entirety.

[0002] The present technology generally relates to medical device methods and systems, such as methods and systems for the implantation and use of implantable medical devices.

[0003] The cardiac conduction system comprises the sinoatrial (SA) node, the atrioventricular (AV) node, the bundle of His, the bundle branches, and the Purkinje fibers. The heartbeat is initiated in the SA node, which can be described as the natural "pacemaker" of the heart. The electrical pulses caused by the SA node cause the atrial myocardium to contract. The electrical pulses or electrical impulses or signals are conducted to the ventricles through the AV node, which inherently delays conduction to allow the atria to stop contracting before the ventricles begin to contract, thereby providing proper AV synchrony. The electrical pulses are conducted from the AV node to the ventricular myocardium through the bundle of His, the bundle branches, and the Purkinje fibers.

[0004] Patients with conduction system abnormalities, such as AV node poor conduction or SA node dysfunction, can receive an implantable medical device (IMD), such as a pacemaker, to restore a more normal heart rhythm and AV synchronization. Some types of IMDs, such as pacemakers, implantable cardioverter-defibrillators (ICDs), or cardiac resynchronization therapy (CRT) devices provide therapeutic electrical stimulation to the patient's heart through electrodes positioned on one or more implantable endocardial, epicardial, or coronary venous leads in or near the heart. Therapeutic electrical stimulation can be delivered to the heart in the form of pulses or shocks for pacing, cardioversion, or defibrillation. In some cases, the IMD can sense the intrinsic depolarization of the heart and control the delivery of therapeutic stimulation to the heart based on the sensing.

[0005] Delivering therapeutic electrical stimulation to the heart can be used to address cardiac conditions, such as ventricular dyssynchrony, which may occur in a patient. Ventricular dyssynchrony can be described as a lack of synchrony or a difference in the timing of contraction of the left and right ventricles of the heart. Significant differences in contraction timing can reduce cardiac efficiency. CRT delivered to the heart by an IMD can enhance cardiac output by resynchronizing the electromechanical activity of the heart's ventricles. CRT can include "three-chamber pacing" when pacing the right atrium, right ventricle, and left ventricle.

[0006] In addition to cardiac pacing, cardiac arrhythmias may also be treated by delivering shock therapy for cardioversion or defibrillation from, for example, an ICD that can sense the patient's cardiac rhythm and classify the rhythm according to an arrhythmia detection scheme to detect episodes of tachycardia or fibrillation. Detected arrhythmias may include ventricular tachycardia (VT), rapid ventricular tachycardia (FVT), ventricular fibrillation (VF), atrial tachycardia (AT), and atrial fibrillation (AT). Anti-tachycardia pacing (ATP) may be used to treat ventricular tachycardia (VT) to substantially terminate many monomorphic rapid rhythms.

[0007] Dual-chamber medical devices are available that contain electrodes carried by a transvenous atrial lead that can be placed in the right atrium and electrodes carried by a transvenous ventricular lead that can be placed in the right ventricle via the right atrium. The dual-chamber medical device itself is typically implanted in a subcutaneous pouch, and the transvenous lead is threaded into the subcutaneous pouch. The dual-chamber medical device can sense both atrial and ventricular electrical signals, and can provide both atrial pacing and ventricular pacing as needed to promote normal heart rhythm and AV synchrony. Some dual-chamber medical devices can treat atrial arrhythmias and ventricular arrhythmias.

[0008] It has been proposed or suggested that intracardiac medical devices such as leadless pacemakers be implanted completely within the patient's heart, thereby eliminating the need for transvenous leads. A leadless pacemaker may include one or more electrodes on its housing to deliver therapeutic electrical signals and / or sense intrinsic depolarization of the heart. An intracardiac medical device may provide cardiac therapy functions, such as sensing and pacing, within a single chamber of the patient's heart. Single-chamber intracardiac devices may also treat atrial or ventricular arrhythmias or fibrillation. Some leadless pacemakers are not intracardiac and may be positioned outside the heart, and in some instances, may be anchored to the heart wall via a fixation mechanism.

[0009] In some patients, a single chamber device may adequately meet the patient's needs. In other patients, single chamber sensing and therapy may not fully address cardiac conduction disease or abnormalities in all patients (e.g., patients with some forms of AV dyssynchrony or tachycardia). In addition to ICD functionality in some cases, dual chamber sensing and / or pacing functionality may be used to restore a more normal heart rhythm. Summary of the invention

[0010] The technology of the present disclosure generally relates to methods and systems for delivering an implantable medical device for left ventricular pacing to an implantation site, for example, adjacent to or within the triangle of Koch region of a patient's heart. In some embodiments, the implantation site can be accessed using the coronary sinus system of the patient's heart. The delivery system can include a sheath having two or more bends to facilitate delivery of a pacing lead to the implantation site. The pacing lead can include a lumen, the size of which can be appropriately set to accommodate a guidewire. The pacing lead can also include a fixation element attached to cardiac tissue. Specifically, the pacing lead can be configured to attach to an implantation site in the right atrial endocardium adjacent to or within the triangle of Koch region in the right atrium of the patient's heart.

[0011] In one aspect, the present disclosure provides a method for delivering a pacing lead, comprising: positioning a potential implantation site adjacent to or within a Koch's triangle region in the right atrium of a patient's heart. The method also comprises advancing a pacing lead to the potential implantation site. The pacing lead comprises an elongated body extending from a proximal portion to a distal portion, and a fixation element coupled to the distal portion and attachable to the right atrial endocardium adjacent to or within the Koch's triangle region in the right atrium of the patient's heart. The method also comprises implanting the pacing lead at the potential implantation site to deliver cardiac therapy to the left ventricle or sense electrical activity of the left ventricle in a basal region, a septal region, or a basal-septal region of the left ventricular myocardium of the patient's heart.

[0012] On the other hand, the present disclosure provides a pacing lead delivery system, comprising: a sheath having an elongated body defining a lumen extending between a proximal portion and a distal portion; a guidewire capable of being at least partially disposed in the lumen of the sheath; a needle-tipped dilator configured to advance over the guidewire and engage tissue in a potential implantation site; and a pacing lead having an elongated body and a fixation element, the elongated body extending from the proximal portion to the distal portion, the fixation element being coupled to the distal portion and attachable to an implantation site in the right atrial endocardium adjacent to or within the Koch's triangle region in the right atrium of a patient's heart to deliver cardiac therapy to the left ventricle or sense electrical activity in the basal region, septal region, or basal-septal region of the left ventricular myocardium of the patient's heart.

[0013] On the other hand, the present disclosure provides a pacing lead comprising an elongated body defining a lumen extending from a proximal portion to a distal portion, the lumen being configured to receive a guide wire; and a left ventricular electrode capable of being implanted through the right atrial endocardium from tissue adjacent to or within the Koch's triangle area of ​​the right atrium to deliver cardiac therapy to the left ventricle or sense electrical activity of the left ventricle in a basal region, a septal region, or a basal-septal region of the left ventricular myocardium of the patient's heart.

[0014] On the other hand, the present disclosure provides a pacing lead delivery system, comprising a sheath having an elongated body defining a lumen extending between a proximal portion and a distal portion; a guidewire that can be at least partially disposed in the lumen of the sheath and is configured to engage tissue in a potential implantation site; and a pacing lead having an elongated body and a fixation element, the elongated body extending from the proximal portion to the distal portion, the fixation element being coupled to the distal portion and attachable to an implantation site in the right atrial endocardium adjacent to or within the Koch's triangle area in the right atrium of the patient's heart to reach the left ventricle or sense electrical activity in the left ventricle in a basal region, a septal region, or a basal-septal region of the left ventricular myocardium of the patient's heart.

[0015] The details of one or more aspects of the disclosure are set forth in the drawings and description below. Other features, objects, and advantages of the techniques described in this disclosure will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is used with, for example Figure 29-34 Conceptual diagram of an illustrative cardiac therapy system including an intracardiac medical device implanted in a patient's heart and a separate medical device positioned outside of the patient's heart for use in conjunction with an illustrative method.

[0017] Figure 2-4 is used with, for example Figure 29-34 Conceptual diagram of an illustrative cardiac therapy system including a medical device including leads having electrodes implanted in a patient's heart for use in conjunction with an illustrative method of

[0018] Figure 5 yes Figure 1 A magnified conceptual illustration of an intracardiac medical device and the anatomy of a patient's heart.

[0019] Figure 6 is used with, for example Figure 1-4 and Figure 16-28Conceptual diagram of a patient's heart diagram in a standard 17-segment view of the left ventricle showing various electrode implant locations for use with an illustrative system and device.

[0020] Figure 7 is used with, for example Figure 1-4 and Figure 16-28 A perspective view of an intracardiac medical device having a distal fixation and electrode assembly including a distal housing-based electrode implemented as a ring electrode for use with illustrative systems and devices of the present invention.

[0021] Figure 8 can be surrounded by, for example Figure 1-4 and Figure 16-28 A block diagram of illustrative circuitry within the housing of a medical device to provide the functions and therapies described herein.

[0022] Fig. 9 is used with, for example Figure 1-4 and Figure 16-28 A perspective view of another illustrative intracardiac medical device for use with the illustrative systems and devices of FIG.

[0023] Fig.10 is used with, for example Figure 1-4 and Figure 16-28 A flow chart of an illustrative method of using an atrial motion detector to detect atrial activity for use with an illustrative system and apparatus.

[0024] Fig.11 is used with, for example Figure 1-4 and Figure 16-28 An illustrative system and apparatus are used together with a flow chart of an illustrative method of detecting heart sounds for representing physiological response information.

[0025] Fig.12 is used with, for example Figure 1-4 and Figure 16-28 An illustrative system and apparatus are used together with a flow chart of an illustrative method of detecting bioimpedance for representing physiological response information.

[0026] Fig.13 is used with, for example Figure 1-4 and Figure 16-28 Figure 2 is a diagram of an illustrative system including an electrode device, a display device, and a computing device for use with illustrative systems and apparatus.

[0027] Figure 14-15 is used with, for example Figure 1-4 and Figure 16-28 A diagram of an illustrative external electrode device for measuring trunk-surface potential used in conjunction with an illustrative system and apparatus.

[0028] Figure 16-25 is shown for example Figure 1-4 Illustrative systems and apparatus of Figure 29-34 Illustration of various configurations of a pacing lead delivery system for use with the method.

[0029] Fig.26 is a right anterior oblique section of the patient's heart and Figure 16-25 Illustration of an illustrative pacing lead delivery system.

[0030] Fig. 27 is a top view of the patient's heart and a cross-sectional view of the Fig.26 The same positioning shown in Figure 16-25 Illustration of an illustrative pacing lead delivery system.

[0031] Fig.28 is shown for example Figure 1-4 Illustrative systems and apparatus and Figure 16-25 Illustration of an illustrative pacing lead delivery system for use with a target implantation zone in a patient's heart.

[0032] Fig.29 is to use, for example Figure 1-4 Illustrative systems and apparatus and Figure 16-28 A flow chart of an illustrative pacing lead delivery system method.

[0033] Fig.30 is used with, for example Fig.29 An illustrative method is used together with a flow chart of an example of a method for locating a potential implantation site.

[0034] Fig.31 is used with, for example Fig.29 The illustrative method is used together with a flow chart of an additional example of a method for locating a potential implantation site.

[0035] Fig.32 is used with, for example Fig.29 An illustrative method is used together with a flow chart of an example of a method for preparing an implantation site.

[0036] Fig.33 is used with, for example Fig.29 An illustrative method is used together with a flow chart of another example of a method for preparing an implantation site.

[0037] Fig.34 is used with, for example Fig.29 The illustrative method is used together with a flow chart of an additional example of a method for preparing an implantation site. DETAILED DESCRIPTION

[0038] The technology disclosed herein generally relates to delivering an implantable medical device to provide cardiac therapy using the cardiac conduction system or the left ventricular myocardium. Specifically, the delivery system and technology can be used to implant an implantable medical device from the Koch triangle area or the coronary sinus through the right atrium to the left ventricle (e.g., atrium to ventricle or VfA). In some embodiments, the various techniques described herein can be applied to His bundle or bundle branch pacing applications using the cardiac conduction system. Various non-limiting examples of cardiac therapy include single-chamber or multi-chamber pacing (e.g., dual-chamber or triple-chamber pacing), atrioventricular synchronous pacing, asynchronous pacing, triggered pacing, cardiac resynchronization pacing or tachycardia-related therapy. Although implantable medical devices such as pacemakers or ICDs are referenced herein, the methods and processes can be used together with any medical device, system or method related to the patient's heart. Various other applications will become apparent to those skilled in the art who benefit from the present disclosure.

[0039] It may be beneficial to provide an implantable medical device delivery system and technique to position electrodes or the cardiac conduction system for sensing or pacing the left ventricular myocardium. It may also be beneficial to provide a delivery system and technique to deliver an implantable medical device adjacent to or within the Koch's triangle, for example using the endocardium and / or the cardiac conduction system at an appropriate angle for left ventricular pacing.

[0040] As used herein, the term "capture" generally refers to obtaining information or data, such as that related to imaging. The term "capture" in the context of pacing (e.g., effectively capturing the heart from pacing) refers to determining whether an expected response in response to a stimulus is sensed, such as sensing expected electrical activity in response to an electrical pulse delivered to a portion of the heart.

[0041] As used herein, the term "effective" generally refers to conditions that are sufficient to perform a particular function for one of ordinary skill in the art. For example, when electrical or mechanical activity of the left ventricle is sensed and determined, effective pacing of the left ventricle may result in capture of the left ventricle to provide the desired cardiac therapy.

[0042] The present disclosure provides a technique for delivering an implantable medical device for left ventricular pacing to an implantation site, for example, adjacent to or within a Koch's triangle region of a patient's heart. In some embodiments, the coronary sinus system of the patient's heart can be used to access the implantation site. Specifically, a delivery system and technique can be used to deliver a pacing lead to an implantation site. The delivery system can include a sheath having two or more bends to facilitate delivery of the pacing lead to the implantation site. The pacing lead can include a lumen, the size of which can be appropriately set to accommodate a guidewire. The pacing lead can also include a fixing element attached to cardiac tissue. Specifically, the pacing lead can be configured to attach to an implantation site in the right atrial endocardium adjacent to or within a Koch's triangle region in the right atrium of the patient's heart.

[0043] In some embodiments, the tissue piercing electrode can be implanted in the basal region, septal region, or basal-septal region of the left ventricular myocardium of the patient's heart from the Koch triangle region of the right atrium through the right atrial endocardium and the central fiber body. In a leadless implantable medical device, the tissue piercing electrode can extend leadlessly from the distal region of the housing of the device, and the right atrial electrode can be connected to the housing (e.g., a portion of the housing or positioned on the outside of the housing) without a lead. A right atrial motion detector may be within the implantable medical device. In a leaded implantable medical device, one or more of the electrodes can be connected to the housing using an implantable lead. When the device is implanted, the electrodes can be used to sense electrical activity in one or more atria and / or ventricles of the patient's heart. The motion detector can be used to sense mechanical activity in one or more atria and / or ventricles of the patient's heart. Specifically, the activity of the right atrium and left ventricle can be monitored, and optionally, the activity of the right ventricle can be monitored. The electrodes can be used to deliver cardiac therapy, such as single chamber pacing for atrial fibrillation, atrioventricular synchronous pacing for bradycardia, asynchronous pacing, triggered pacing, cardiac resynchronization pacing for ventricular asynchrony, anti-tachycardia pacing, or shock therapy. Shock therapy can be initiated by an implantable medical device. A separate medical device (e.g., an extravascular ICD, which can also be implanted) can be in operational communication with the implantable medical device and can deliver an electric shock in response to a trigger such as a signaling pulse (e.g., a trigger, signaling, or a unique electrical pulse) provided by the device.

[0044] Generally, electrical or mechanical activity can be sensed, determined, acquired or monitored using various techniques available to those of ordinary skill in the art having the benefit of this disclosure. As used herein, the term "monitoring" generally refers to sensing, acquiring or receiving data or information that can be used (e.g., processed or stored).

[0045] The present disclosure also provides techniques for delivering and implanting a medical device, for example, in the Koch's triangle region in the right atrium. Various devices can be used to identify the general location of the Koch's triangle region, which can be described as an implantation site. A flexible lead or other probe can be advanced to a potential implantation site and used to identify the precise location of an implanted medical device (e.g., an electrode, a wire, a lead, or an intracardiac device). Specifically, the techniques of the present disclosure can be used to implant a device to provide synchronized pacing to an asynchronous patient, and to provide dual-chamber pacing to a bradycardic patient with moderate heart failure.

[0046] Figure 1-4 It is shown that one can use, for example Figure 29-34 1 and 2. Examples of various cardiac therapy systems for delivering a medical device to an implantation site are shown in the method implanted in FIG. 1. In these views, the left ventricle (LV) is generally positioned behind the right ventricle (RV).

[0047] Although the present disclosure describes both leadless and leaded implantable medical devices, reference is first made to a conceptual diagram of a cardiac therapy system 2. Figure 1 , the cardiac therapy system includes an intracardiac medical device 10 that can be configured for single-chamber or dual-chamber therapy and implanted in a patient's heart 8. In some embodiments, the device 10 can be configured for single-chamber pacing, and can, for example, switch between single-chamber pacing and multi-chamber pacing (e.g., dual-chamber or triple-chamber pacing). As used herein, "intracardiac" refers to a device that is configured to be completely implanted within a patient's heart, for example, to provide cardiac therapy. The device 10 is shown implanted in the right atrium (RA) of the patient's heart 8 at a target implantation area 4. The device 10 may include one or more fixation members 20 that anchor the distal end of the device against the atrial endocardium in the target implantation area 4. The target implantation area 4 may be located between the bundle of His 5 (bundle of His) and the coronary sinus 3, and may be adjacent to the tricuspid valve 6. Device 10 may be described as an atrium-to-ventricle (VfA) device that may sense or provide therapy to one or both ventricles (e.g., the right ventricle, the left ventricle, or both ventricles, as appropriate) while typically being placed in the right atrium. Specifically, device 10 may include a tissue-piercing electrode that may be implanted in the basal region, septal region, or basal-septal region of the left ventricular myocardium of the patient's heart from the Koch triangle region of the right atrium through the right atrial endocardium and the central fiber body.

[0048] The device 10 can be described as a leadless implantable medical device. As used herein, "leadless" refers to a device that has no leads extending from the patient's heart 8. In other words, a leadless device can have leads that do not extend from the outside of the patient's heart to the inside of the patient's heart. Some leadless devices can be introduced through a vein, but once implanted, the device does not have or may not include any transvenous leads and can be configured to provide cardiac therapy without the use of any transvenous leads. Further, specifically, the leadless VfA device does not use leads to be operably connected to electrodes in the ventricle when the housing of the device is positioned in the atrium. In addition, the leadless electrodes can be coupled to the housing of the medical device without the use of leads between the electrodes and the housing.

[0049] The device 10 may include a dart electrode assembly 12 that defines or has a straight axis extending from a distal region of the device 10. The dart electrode assembly 12 may be placed or at least configured to be placed through the atrial myocardium and the central fiber body and into the ventricular myocardium 14 or along the ventricular septum without passing completely through the ventricular endocardial or epicardial surface. The dart electrode assembly 12 may carry or include an electrode at the distal region of the axis so that the electrode may be positioned within the ventricular myocardium for sensing ventricular signals and delivering ventricular pulses (e.g., depolarizing the left ventricle to cause contraction of the left ventricle). In some instances, the electrode at the distal region of the axis is a cathode electrode provided for use in a bipolar electrode pair for pacing and sensing. Although the implantation area 4 shown may enable one or more electrodes of the dart electrode assembly 12 to be positioned in the ventricular myocardium, it should be recognized that devices having aspects disclosed herein may be implanted in other locations, as appropriate, for multi-chamber pacing (e.g., dual-chamber or triple-chamber pacing), single-chamber pacing with multi-chamber sensing, single-chamber pacing and / or sensing, or other clinical therapies and applications.

[0050] It should be understood that although the device 10 is described herein as including a single dart electrode assembly, the device 10 may include more than one dart electrode assembly that is placed or configured to be placed through the atrial myocardium and central fiber body and into the ventricular myocardium 14 or along the ventricular septum without passing completely through the ventricular endocardial or epicardial surfaces. In addition, each dart electrode assembly may carry or include more than a single electrode at the distal region of the shaft or at other regions along the shaft (e.g., the proximal region or the central region).

[0051] The cardiac therapy system 2 may also include a separate medical device 50 (in Figure 1), the separate medical device can be positioned outside the patient's heart 8 (e.g., subcutaneously) and can be operably connected to the patient's heart 8 to deliver cardiac therapy thereto. In one instance, the separate medical device 50 can be an extravascular ICD. In some embodiments, the extravascular ICD can include a defibrillation lead that includes or carries a defibrillation electrode. A therapy carrier can be present between the defibrillation electrode on the defibrillation lead and the housing electrode of the ICD. In addition, one or more electrodes of the ICD can also be used to sense electrical signals related to the patient's heart 8. The ICD can be configured to deliver shock therapy including one or more defibrillation or cardioversion shocks. For example, if an arrhythmia is sensed, the ICD can send pulses through the electrical leads to shock the heart and restore its normal rhythm. In some instances, the ICD can deliver shock therapy without placing electrical leads in the heart or attaching wires directly to the heart (subcutaneous ICD). An example of an extravascular subcutaneous ICD that may be used with the system 2 described herein may be described in U.S. Patent No. 9,278,229 (Reinke et al.), issued on March 8, 2016, which is incorporated herein by reference in its entirety.

[0052] In the case of shock therapy (e.g., a defibrillation shock provided by a defibrillation electrode of a defibrillation lead), a separate medical device 50 (e.g., an extravascular ICD) can include a control circuit that uses a therapy delivery circuit to generate a defibrillation shock having any of a variety of waveform characteristics (including leading edge voltage, slope, energy delivered, pulse phase, etc.). The therapy delivery circuit can, for example, generate a monophasic, biphasic, or multiphasic waveform. In addition, the therapy delivery circuit can generate a defibrillation waveform with different amounts of energy. For example, the therapy delivery circuit can generate a defibrillation waveform that delivers a total of between approximately 60-80 joules (J) of energy for subcutaneous defibrillation.

[0053] The individual medical device 50 may further include a sensing circuit. The sensing circuit may be configured to obtain an electrical signal sensed by one or more combinations of electrodes, and process the obtained signal. The components of the sensing circuit may include analog components, digital components, or a combination thereof. The sensing circuit may, for example, include one or more readout amplifiers, filters, rectifiers, threshold detectors, analog-to-digital converters (ADCs), etc. The sensing circuit may convert the sensed signal into a digital form, and provide the digital signal to the control circuit for processing and / or analysis. For example, the sensing circuit may amplify the signal from the sensing electrode, and may convert the amplified signal into a multi-bit digital signal by the ADC, and then provide the digital signal to the control circuit. In one or more embodiments, the sensing circuit may also compare the processed signal with a threshold value to detect the presence of atrial or ventricular depolarization (e.g., P wave or R wave) and indicate the presence of atrial depolarization (e.g., P wave) or ventricular depolarization (e.g., R wave) to the control circuit.

[0054] The device 10 and the separate medical device 50 can cooperate to provide cardiac therapy to the patient's heart 8. For example, the device 10 and the separate medical device 50 can be used to detect tachycardia, monitor tachycardia, and / or provide tachycardia-related therapy. For example, the device 10 can communicate wirelessly with the separate medical device 50 to trigger shock therapy using the separate medical device 50. As used herein, "wireless" refers to an operational connection or connection between the device 10 and the separate medical device 50 without the use of metal conductors. In one example, wireless communication can use a unique, signaling, or triggering electrical pulse provided by the device 10 that is conducted through the patient's tissue and can be detected by the separate medical device 50. In another example, wireless communication can use a communication interface (e.g., an antenna) of the device 10 to provide electromagnetic radiation that propagates through the patient's tissue and can be detected, for example, using a communication interface (e.g., an antenna) of the separate medical device 50.

[0055] refer to Figure 2, the cardiac therapy system 402 can include a leaded medical device 408, the leaded medical device including one or a single implantable lead 410 having a tissue-piercing electrode assembly 12 coupled to a distal region of the lead and implanted within the patient's heart 8. The housing 420 of the leaded medical device 408 can be implanted and positioned outside the patient's heart 8 and is configured to calibrate pacing therapy and / or deliver pacing therapy. The lead 410 can include a right atrial electrode, and the device 408 can be used as a device with a dual channel (e.g., pacing and / or sensing in both the right atrium and the left ventricle). In some embodiments, the lead 410 may not include a right atrial electrode. In other words, the leaded medical device 408 can be a single-channel device that can be used for asynchronous, triggered, or other types of single-channel pacing. The leaded medical device 408 can use the lead 410 to puncture the tissue-piercing electrode assembly 12, for example, as described with respect to Figure 1 The same or similar approaches described herein sense activity or deliver pacing to the left ventricle (LV) when implanted.

[0056] refer to Figure 3 The cardiac therapy system 404 may include a leaded medical device 418 similar to Figure 2 The leaded medical device 408 is a device 418, except that the device 418 includes two implantable leads 410, 412. Specifically, the implantable lead 412 can include an electrode (e.g., a right atrial electrode) coupled to a distal region of the lead 412 and can be implanted in a different location than the lead 410. In some embodiments, the lead 412 is implanted in a different region of the right atrium. In some embodiments, each lead 410, 412 can contribute to one channel of the dual channel device 418. For example, the lead 410 can be a tissue piercing electrode of the tissue piercing electrode assembly 12, for example, as described with respect to Figure 1 The same or similar manner described above can sense activity or deliver pacing to the left ventricle (LV) when implanted, and lead 412 can sense activity or deliver pacing to the right atrium (RA).

[0057] refer to Figure 4 The cardiac therapy system 406 may include a leaded medical device 428 similar to Figure 3The leaded medical device 418 includes three implantable leads 410, 412, 414, except that the device 428 includes three implantable leads 410, 412, 414. Specifically, the implantable lead 414 can include an electrode (e.g., a right ventricular electrode) coupled to a distal region of the lead 414, and can be implanted in a different location than the leads 410, 412. As shown, the implantable lead 414 extends from the right atrium (RA) to the right ventricle (RV) through the tricuspid valve 6. In some embodiments, the lead 414 is implanted in the region of the right ventricle. In some embodiments, each lead 410, 412, 414 can contribute one channel to the multi-channel device 428. For example, the lead 410 can be located in the tissue piercing electrode assembly 12, for example, as described with respect to Figure 1 In the same or similar manner as described, when implanted to sense activity or deliver pacing to the left ventricle (LV), lead 412 can sense activity from delivering pacing to the RA, and lead 414 can sense activity or deliver pacing to the RV.

[0058] In some embodiments, the pacing delay (e.g., RV-LV pacing delay, or more generally, VV pacing delay) between the RV electrode on lead 414 for pacing the RV and the LV electrode on lead 410 for pacing the LV can be calibrated or optimized, for example, using a separate medical device such as an electrode device (e.g., an ECG strip). Various methods can be used to calibrate or optimize the VV delay. In some embodiments, the medical device 428 can be used to test pacing at multiple different VV delays. For example, the RV can be paced approximately 80, 60, 40, and 20 milliseconds (ms) before the LV, and the LV can be paced approximately 80, 60, 40, and 20 milliseconds before the RV, as well as pacing the RV-LV simultaneously (e.g., a VV pacing delay of approximately 0 milliseconds). The medical device 428 can then be configured, for example, to automatically select a VV pacing delay that, when used for pacing, corresponds to the minimum electrical dyssynchrony measured using the electrode device. Test pacing at different VV pacing delays may be performed using a specific AV delay (eg, a nominal AV delay set by medical device 428) or with a predetermined optimal AV delay based on patient characteristics.

[0059] Figure 5 yes Figure 1 1 and an enlarged conceptual diagram of an intracardiac medical device 10 and the anatomical structure of a patient's heart 8. Specifically, the device 10 is configured to sense electrical activity and / or deliver pacing therapy. The intracardiac device 10 may include a housing 30. The housing 30 may define the internal components of the device 10 (e.g., in combination with Figure 8The housing 30 may be formed of a hermetically sealed internal cavity in which the sensing circuitry, therapy delivery circuitry, control circuitry, memory, telemetry circuitry, other optional sensors, and power supplies (generally described) reside. The housing 30 may be formed of a conductive material including titanium or a titanium alloy, stainless steel, MP35N (a non-magnetic nickel-cobalt-chromium-molybdenum alloy), a platinum alloy, or other biocompatible metal or metal alloy. In other examples, the housing 30 may be formed of a non-conductive material including ceramic, glass, sapphire, silicone, polyurethane, epoxy, acetyl copolymer plastic, polyetheretherketone (PEEK), a liquid crystal polymer, or other biocompatible polymer.

[0060] In at least one embodiment, the housing 30 can be described as extending between a distal region 32 and a proximal region 34 in a generally cylindrical shape to facilitate catheter delivery. In other embodiments, the housing 30 can be prismatic or any other shape to perform the functions and utilities described herein. The housing 30 can include, for example, a delivery tool interface member 26 at the proximal region 34 for engaging with a delivery tool during implantation of the device 10.

[0061] All or a portion of the housing 30 may be used as an electrode during cardiac therapy, for example, in sensing and / or pacing. In the illustrated example, the housing-based electrode 24 is shown as being externally connected to a proximal portion of the housing 30 (e.g., closer to the proximal region 34 than the distal region 32). When the housing 30 is formed of a conductive material (e.g., a titanium alloy or other examples listed above), portions of the housing 30 may be electrically insulated by a non-conductive material (e.g., a coating of parylene, polyurethane, silicone, epoxy, or other biocompatible polymers) to expose one or more discrete areas of the conductive material to define the proximal housing-based electrode 24. When the housing 30 is formed of a non-conductive material such as a ceramic, glass, or polymer material, a conductive coating or layer such as titanium, platinum, stainless steel, or alloys thereof may be applied to one or more discrete areas of the housing 30 to form the proximal housing-based electrode 24. In other examples, the proximal housing-based electrode 24 may be a component mounted or assembled to the housing 30, such as a ring electrode. The proximal housing-based electrode 24 may be electrically coupled to the internal circuitry of the device 10 , for example, through the conductive housing 30 , or through electrical conductors when the housing 30 is a non-conductive material.

[0062] In the illustrated example, the proximal housing-based electrode 24 is positioned closer to the housing proximal region 34 than the housing distal region 32, and is therefore referred to as a "proximal housing-based electrode" 24. However, in other examples, the housing-based electrode 24 may be positioned at other locations along the housing 30, for example, further away from the illustrated location.

[0063] At the distal region 32, the device 10 can include a distal fixation and electrode assembly 36, which can include one or more fixation members 20 and one or more dart electrode assemblies 12 of equal or unequal length. In one example, a single dart electrode assembly 12 includes a shaft 40 extending distally away from the housing distal region 32, and one or more electrode elements, such as a tip electrode 42, at or near the free distal region of the shaft 40. The tip electrode 42 can have a conical or hemispherical distal tip with a relatively narrow tip diameter (e.g., less than about 1 millimeter (mm)) for penetrating and passing through tissue layers without the use of a sharp tip or a needle tip with a sharp or beveled edge.

[0064] The shaft 40 of the dart electrode assembly 12 can normally be a straight member and can be rigid. In other embodiments, the shaft 40 can be described as being relatively rigid, but still having limited flexibility in the lateral direction. In addition, the shaft 40 can be non-rigid to allow some lateral bending to occur with heart movement. However, in a relaxed state, when not subjected to any external force, the shaft 40 can maintain a straight position as shown to space the tip electrode 42 from the housing distal region 32 by at least the height 47 of the shaft 40. In other words, the dart electrode assembly 12 can be described as being elastic.

[0065] The dart electrode assembly 12 can be configured to pierce one or more tissue layers to position the tip electrode 42 within a desired tissue layer (e.g., ventricular myocardium). As such, the height 47 or length of the shaft 40 can correspond to the expected pacing site depth, and the shaft 40 can have a relatively high compressive strength along its longitudinal axis to resist bending in a lateral or radial direction when pressed against the implantation region 4. If a second dart electrode assembly 12 is employed, its length may not be equal to the expected pacing site depth and may be configured to act as an indifferent electrode for delivering pacing energy to tissue. A longitudinal axial force may be applied to the tip electrode 42, such as by applying a longitudinal thrust to the proximal region 34 of the housing 30, to advance the dart electrode assembly 12 into tissue within the target implantation region. The shaft 40 may be described as being longitudinally non-compressible and / or elastically deformable in a transverse or radial direction when subjected to a transverse or radial force to allow, for example, temporary bending with tissue movement, but may return to its normal straight position when the transverse force is reduced. When the shaft 40 is not exposed to any external forces or is only exposed to forces along its longitudinal center axis, the shaft 40 may maintain a straight linear orientation as shown.

[0066] One or more fixation members 20 can be described as having one or more "tines" in a normal curved position. The tines can be maintained in a distally extending position within the delivery tool. The distal tips of the tines can penetrate the cardiac tissue to a limited depth and then elastically bend proximally back to the (shown) normal curved position once they are released from the delivery tool. Further, the fixation member 20 can include, for example, one or more aspects described in U.S. Patent No. 9,675,579 (Grubac et al.), issued on June 13, 2017, and U.S. Patent No. 9,119,959 (Rys et al.), issued on September 1, 2015, each of which is incorporated herein by reference in its entirety.

[0067] In some examples, the distal fixation and electrode assembly 36 includes a distal shell-based electrode 22. In the case of using the device 10 as a pacemaker for multi-chamber pacing (e.g., dual-chamber or triple-chamber pacing) and sensing, the tip electrode 42 can be used as a cathode electrode paired with the proximal shell-based electrode 24 that acts as a return anode electrode. Alternatively, the distal shell-based electrode 22 can act as a return anode electrode paired with the tip electrode 42 for sensing ventricular signals and delivering ventricular pacing pulses. In other examples, the distal shell-based electrode 22 can be a cathode electrode for sensing atrial signals and delivering pacing pulses to the atrial myocardium in the target implant area 4. When the distal shell-based electrode 22 acts as an atrial cathode electrode, the proximal shell-based electrode 24 can act as a return anode paired with the tip electrode 42 for ventricular pacing and sensing, and can act as a return anode paired with the distal shell-based electrode 22 for atrial pacing and sensing.

[0068] As shown in this illustration, in some pacing applications, the target implantation area 4 is along the atrial endocardium 18, typically below the AV node 15 and the bundle of His 5. The dart electrode assembly 12 can at least partially define a height 47 or length of the shaft 40 to pass through the atrial endocardium 18 in the target implantation area 4, through the central fiber body 16, and into the ventricular myocardium 14 without penetrating the ventricular endocardial surface 17. When the height 47 or length of the dart electrode assembly 12 is fully advanced into the target implantation area 4, the tip electrode 42 can be placed within the ventricular myocardium 14, and the distal housing-based electrode 22 can be positioned in close contact with or in close proximity to the atrial endocardium 18. In various examples, the dart electrode assembly 12 can have a total combined height 47 or length of the tip electrode 42 and the shaft 40 of about 3 mm to about 8 mm. The diameter of the shaft 40 can be less than about 2 mm, and can be about 1 mm or less, or even about 0.6 mm or less.

[0069] The device 10 may include an acoustic or motion detector 11 within the housing 30. The acoustic or motion detector 11 may be operably coupled to a control circuit 80 ( Figure 8 )、Sensing circuit 86( Figure 8 ) or therapy delivery circuit 84 ( Figure 8 ). In some embodiments, the acoustic or motion detector 11 may be used with Figure 10-12 The acoustic or motion detector 11 can be used together with the method 600, 650 or 800 shown in . The acoustic or motion detector 11 can be used to monitor mechanical activity, such as atrial mechanical activity (e.g., atrial contraction) and / or ventricular mechanical activity (e.g., ventricular contraction). In some embodiments, the acoustic or motion detector 11 can be used to detect right atrial mechanical activity. Non-limiting examples of the acoustic or motion detector 11 include an accelerometer or a microphone. In some embodiments, the mechanical activity detected by the acoustic or motion detector 11 can be used to supplement or replace the electrical activity detected by one or more of the electrodes of the device 10. For example, the acoustic or motion detector 11 can be used in addition to the proximal shell-based electrode 24 or as an alternative to the proximal shell-based electrode.

[0070] The acoustic or motion detector 11 may also be used for rate response detection or to provide a rate responsive IMD. Various techniques related to rate response may be described in U.S. Pat. No. 5,154,170 (Bennett et al.), entitled "Optimization for rate responsive cardiac pacemaker," issued Oct. 13, 1992, and U.S. Pat. No. 5,562,711 (Yerich et al.), entitled "Method and apparatus for rate-responsive cardiac pacing," issued Oct. 8, 1996, each of which is incorporated herein by reference in its entirety.

[0071] In various embodiments, an acoustic or motion detector 11 (or motion sensor) can be used as a HS sensor and can be implemented as a microphone or a 1-axis, 2-axis, or 3-axis accelerometer. In one embodiment, the acoustic sensor is implemented as a piezoelectric crystal mounted within the implantable medical device housing and responsive to mechanical motion associated with heart sounds. The piezoelectric crystal can be a dedicated HS sensor or can be used for multiple functions. In the illustrative embodiment shown, the acoustic sensor is embodied in the form of a piezoelectric crystal, which is also used to generate a patient alarm signal in the form of a perceptible vibration of the IMD housing. When an alarm condition is detected, the control circuit 80 can cause the patient alarm control circuit system to generate an alarm signal by activating the piezoelectric crystal.

[0072] The control circuitry may be used to control whether the piezoelectric crystal is used in a "listen mode" to sense HS signals through the HS sensing circuitry, or in an "output mode" to generate a patient alarm. During patient alarm generation, the HS sensing circuitry may be temporarily disconnected from the HS sensor by the control circuitry.

[0073] Examples of other embodiments of acoustic sensors that may be suitable for implementation with the presently disclosed techniques may be generally described in U.S. Pat. No. 4,546,777 (Groch et al.), U.S. Pat. No. 6,869,404 (Schulhauser et al.), U.S. Pat. No. 5,554,177 (Kieval et al.), and U.S. Pat. No. 7,035,684 (Lee et al.), each of which is incorporated herein by reference in its entirety.

[0074] Various types of acoustic sensors may be used. The acoustic sensor may be any implantable or external sensor that responds to one or more of the heart sounds generated as previously described, and thereby produces an analog electrical signal that is related in time and amplitude to the heart sounds. The analog signal may then be processed by the HS sensing module (which may include digital conversion) to obtain HS parameters such as amplitude or relative time intervals derived by the HS sensing module or control circuit 80. The acoustic sensor and HS sensing module may be incorporated into an IMD capable of delivering CRT or another cardiac therapy being optimized, or may be implemented in a separate device that communicates wired or wirelessly with the IMD or in an external programmer or computer used during a pacing parameter optimization procedure as described herein.

[0075] Figure 6300 (e.g., a top-down view) of a patient's heart showing a left ventricle 320 and a right ventricle 322 in a standard 17-segment view. The diagram 300 includes a plurality of zones 326 corresponding to different regions of a human heart. As shown, the zones 326 are numbered 1-17 (e.g., corresponding to the 17 segments of the left ventricle of a human heart). The zones 326 of the diagram 300 may include a basal anterior zone 1, a basal anterior septal zone 2, a basal inferolateral zone 3, a basal inferolateral zone 4, a basal inferolateral zone 5, a basal anterolateral zone 6, a mid-anterior zone 7, a mid-anterior septal zone 8, a mid-inferolateral septal zone 9, a mid-inferolateral zone 10, a mid-inferolateral zone 11, a mid-anterolateral zone 12, an apical anterior zone 13, an apical septal zone 14, an apical inferolateral zone 15, an apical lateral zone 16, and an apex zone 17. Also shown are the inferior and anterior septal regions of the right ventricle 322, as well as the right bundle branch (RBB) and left bundle branch (LBB).

[0076] In some embodiments, any of the tissue piercing electrodes of the present disclosure can be implanted in the basal region, septal region, or basal-septal region of the left ventricular myocardium of the patient's heart. Specifically, the tissue piercing electrode can be implanted from the Koch triangle region of the right atrium through the right atrial endocardium and the central fiber body.

[0077] Once implanted, the tissue-piercing electrode can be positioned at a target implantation region 4 such as the basal region, septal region, or basal-septal region of the left ventricular myocardium. Figure 1-5 ). Referring to FIG. 300 , the basal region includes one or more of the basal anterior region 1, the basal anterior septal region 2, the basal inferior septal region 3, the basal inferior region 4, the mid-anterior region 7, the mid-anterior septal region 8, the mid-inferior septal region 9, and the mid-inferior region 10. Referring to FIG. 300 , the septal region includes one or more of the basal anterior septal region 2, the basal anterior septal region 3, the mid-anterior septal region 8, the mid-inferior septal region 9, and the apical septal region 14.

[0078] In some embodiments, when implanted, the tissue-piercing electrode can be positioned in the basal-septal region of the left ventricular myocardium. The basal septal region can include one or more of the basal anterior septal region 2, the basal inferior septal region 3, the mid-anterior septal region 8, and the mid-inferior septal region 9.

[0079] In some embodiments, when implanted, the tissue-piercing electrode can be positioned in the inferior / posterior basal septal region of the left ventricular myocardium. In some cases, the inferior / posterior basal septal region can be described as the inferior / posterior basal septal region. In some embodiments, the tissue-piercing electrode can be positioned in the posterior superior bulge of the left ventricle. In some embodiments, when implanted, the tissue-piercing electrode can be positioned in the high inferior / posterior basal-septal region of the left ventricular myocardium. The inferior / posterior basal septal region of the left ventricular myocardium can include a portion of one or more of the inferior basal septal region 3 and the middle-lower septal region 9 (e.g., only the inferior basal septal region, only the middle-lower septal region, or both the inferior basal septal region and the middle-lower septal region). For example, the inferior / posterior basal septal region can include an area 324 generally shown as a dashed line boundary. As shown, the dashed line boundary indicates the approximate location of the inferior / posterior basal septal region, which may be slightly different in shape or size depending on the specific application.

[0080] Figure 7 3 is a perspective view of a device 10 capable of calibrating pacing therapy and / or delivering pacing therapy. As shown, the distal fixation and electrode assembly 36 includes a distal shell-based electrode 22 implemented as a ring electrode. When the fixation member tines 20a, 20b, and 20c of the fixation member 20 engage the atrial tissue, the distal shell-based electrode 22 can be positioned in close contact or in operational proximity to the atrial tissue. The elastically deformable tines 20a, 20b, and 20c can extend distally during delivery of the device 10 to the implantation site. For example, when the device 10 is advanced out of the delivery tool, the tines 20a, 20b, and 20c can pierce the atrial endocardial surface and bend back to its normal curved position (as shown) when the tines 20a, 20b, and 20c are no longer constrained in the delivery tool. When the tines 20a, 20b, and 20c are bent back to their normal position, the fixation member 20 can pull the distal fixation member and electrode assembly 36 toward the atrial endocardial surface. When the distal fixation member and electrode assembly 36 is pulled toward the atrial endocardium, the tip electrode 42 can be advanced through the atrial myocardium and the central fiber body and into the ventricular myocardium.The distal housing-based electrode 22 can then be positioned against the atrial endocardial surface.

[0081] The distal shell-based electrode 22 may include a ring formed of a conductive material such as titanium, platinum, iridium, or alloys thereof. The distal shell-based electrode 22 may be a single continuous ring electrode. In other examples, portions of the ring may be coated with an electrically insulating coating, such as polyparaxylene, polyurethane, silicone, epoxy, or other insulating coating, to reduce the conductive surface area of ​​the ring electrode. For example, one or more sectors of the ring may be coated to separate two or more conductive exposed surface areas of the distal shell-based electrode 22. Reducing the conductive surface area of ​​the distal shell-based electrode 22, such as by covering portions of the conductive ring with an insulating coating, may increase the electrical impedance of the distal shell-based electrode 22, and thereby reduce the current delivered during pacing of pulses to capture myocardium (e.g., atrial myocardial tissue). Lower current consumption may save a power source of the device 10, such as one or more rechargeable or non-rechargeable batteries.

[0082] As described above, the distal housing-based electrode 22 can be configured as an atrial cathode electrode for delivering pacing pulses to atrial tissue at the implant site in conjunction with the proximal housing-based electrode 24 as a return anode. The electrodes 22 and 24 can be used to sense atrial P waves for controlling atrial pacing pulses (delivered in the absence of a sensed P wave) and for controlling atrial synchronized ventricular pacing pulses delivered using the tip electrode 42 as a cathode and the proximal housing-based electrode 24 as a return anode. In other examples, the distal housing-based electrode 22 can be used as a return anode in conjunction with the cathode tip electrode 42 for ventricular pacing and sensing.

[0083] Figure 8 is a block diagram of a circuit system, which may be enclosed in a housing 30 ( Figure 7 ) to provide the functionality of calibrating pacing therapy and / or delivering pacing therapy using the device 10 according to one example, or the circuit system is enclosed in any other medical device described herein (e.g., Figure 2 Device 408, Figure 3 Device 418, Figure 4 Device 428 or Fig. 9 The medical device 50 ( Figure 1-4) may include some or all of the same components that may be configured in a similar manner. The electronic circuit system enclosed within the housing 30 may include software, firmware, and hardware that collaboratively monitor atrial and ventricular electrocardiographic signals, determine when cardiac therapy is needed, and / or deliver electrical pulses to the patient's heart according to programmed therapy modes and pulse control parameters. The electronic circuit system may include control circuitry 80 (e.g., including processing circuitry), memory 82, therapy delivery circuitry 84, sensing circuitry 86, and / or telemetry circuitry 88. In some instances, the device 10 includes one or more sensors 90 (e.g., patient activity sensors) for generating signals related to a patient's physiological function, state, or condition for determining the need for pacing therapy and / or controlling the pacing rate. For example, one sensor 90 may include an inertial measurement unit (e.g., an accelerometer) for measuring motion.

[0084] The power supply 98 can provide power as needed to the circuitry of the device 10 including each of the components 80, 82, 84, 86, 88, 90. The power supply 98 can include one or more energy storage devices, such as one or more rechargeable or non-rechargeable batteries. The connection between the power supply 98 and each of the components such as the sensors 80, 82, 84, 86, 88, 90 can be understood from the overall block diagram presented to a person of ordinary skill in the art (not shown). For example, the power supply 98 can be coupled to one or more charging circuits included in the therapy delivery circuit 84 to provide power for charging the holding capacitors included in the therapy delivery circuit 84, which are discharged at appropriate times under the control of the control circuit 80 to deliver pacing pulses, for example, according to a dual chamber pacing mode (such as DDI (R)). The power supply 98 can also be coupled to components of the sensing circuit 86 (such as readout amplifiers, analog-to-digital converters, switching circuitry, etc.), sensors 90, telemetry circuits 88, and memory 82 to provide power to various circuits.

[0085] The functional blocks shown represent the functions included in the device 10 and may include any discrete and / or integrated electronic circuit components that implement analog and / or digital circuits that are capable of producing the functions attributed to the medical device 10 herein. The various components may include processing circuit systems (such as application specific integrated circuits (ASICs), electronic circuits, processors (shared, dedicated or group) and memory) that execute one or more software or firmware programs, combinational logic circuits, state machines, or other suitable components or combinations of components that provide the described functions. The specific form of software, hardware and / or firmware used to implement the functions disclosed herein will be determined primarily by the specific system architecture employed in the medical device and the specific detection and therapy delivery methods employed by the medical device.

[0086] The memory 82 may include any volatile, nonvolatile, magnetic, or electrically non-transitory computer-readable storage medium, such as a random access memory (RAM), a read-only memory (ROM), a nonvolatile RAM (NVRAM), an electrically erasable programmable ROM (EEPROM), flash memory, or any other memory device. In addition, the memory 82 may include a non-transitory computer-readable medium storing instructions that, when executed by one or more processing circuits, cause the control circuit 80 and / or other processing circuit systems to calibrate pacing therapy and / or perform single-chamber, dual-chamber, or triple-chamber calibrated pacing therapy (e.g., single-chamber or multi-chamber pacing) or other cardiac therapy functions attributed to the device 10 (e.g., sensing or delivering therapy). The non-transitory computer-readable medium storing instructions may include any of the media listed above.

[0087] The control circuit 80 can communicate with the therapy delivery circuit 84 and the sensing circuit 86, for example, via a data bus, to sense cardiac electrical signals and control the delivery of cardiac electrical stimulation therapy in response to sensed cardiac events (e.g., P and R waves, or their absence). The tip electrode 42, the distal shell-based electrode 22, and the proximal shell-based electrode 24 can be electrically coupled to the therapy delivery circuit 84 to deliver electrical stimulation pulses to the patient's heart, and to the sensing circuit 86 for sensing cardiac electrical signals.

[0088] The sensing circuit 86 may include an atrial (A) sensing channel 87 and a ventricular (V) sensing channel 89. The distal shell-based electrode 22 and the proximal shell-based electrode 24 may be coupled to the atrial sensing channel 87 to sense atrial signals, such as a P wave accompanying atrial myocardial depolarization. In instances where two or more optional distal shell-based electrodes are included, the sensing circuit 86 may include a switch circuit system for selectively coupling one or more of the available distal shell-based electrodes to the cardiac event detection circuit system included in the atrial sensing channel 87. The switch circuit system may include a switch array, a switch matrix, a multiplexer, or any other type of switch device suitable for selectively coupling components of the sensing circuit 86 to selected electrodes. The tip electrode 42 and the proximal shell-based electrode 24 may be coupled to the ventricular sensing channel 89 to sense ventricular signals, such as an R wave accompanying a ventricular myocardial depolarization.

[0089] Each of the atrial sensing channel 87 and the ventricular sensing channel 89 may include a cardiac event detection circuit system for detecting P waves and R waves, respectively, from cardiac electrical signals received by the corresponding sensing channel. The cardiac event detection circuit system contained in each channel of the channels 87 and 89 may be configured to amplify, filter, digitize and rectify the cardiac electrical signals received from the selected electrodes to improve the signal quality for detecting cardiac electrical events. The cardiac event detection circuit system within each channel 87 and 89 may include one or more sense amplifiers, filters, rectifiers, threshold detectors, comparators, analog-to-digital converters (ADCs), timers, or other analog or digital components. The cardiac event sensing thresholds, such as the P wave sensing threshold and the R wave sensing threshold, may be automatically adjusted by each corresponding sensing channel 87 and 89 under the control of the control circuit 80, for example, based on the timing intervals and sensing thresholds determined by the control circuit 80, stored in the memory 82, and / or controlled by the hardware, firmware, and / or software of the control circuit 80 and / or the sensing circuit 86.

[0090] Upon detecting a cardiac electrical event based on a sensing threshold crossing, the sensing circuit 86 can generate a sensed event signal that is transmitted to the control circuit 80. For example, the atrial sensing channel 87 can generate a P-wave sensed event signal in response to a P-wave sensing threshold crossing. The ventricular sensing channel 89 can generate an R-wave sensed event signal in response to an R-wave sensing threshold crossing. The sensed event signal can be used by the control circuit 80 to set an escape interval timer that controls a base time interval for scheduling cardiac pacing pulses. Depending on the specific programmed pacing mode, the sensed event signal can trigger or inhibit pacing pulses. For example, a P-wave sensed event signal received from the atrial sensing channel 87 can cause the control circuit 80 to inhibit a scheduled atrial pacing pulse and schedule a ventricular pacing pulse at a programmed atrioventricular (AV) pacing interval. If an R-wave is sensed before the AV pacing interval expires, the ventricular pacing pulse can be inhibited. If the AV pacing interval expires before control circuit 80 receives an R-wave sensed event signal from ventricular sensing channel 89, control circuit 80 may use therapy delivery circuit 84 to deliver a scheduled ventricular pacing pulse synchronized with the sensed P-wave.

[0091] In some instances, the device 10 can be configured to deliver a variety of pacing therapies, including bradycardia pacing, cardiac resynchronization therapy, post-shock pacing, and / or tachycardia-related therapies (such as ATP), among others. For example, the device 10 can be configured to detect non-sinus tachycardia and deliver ATP. The control circuit 80 can determine cardiac event time intervals, such as the PP intervals between consecutive P-wave sensed event signals received from the atrial sensing channel 87, the RR intervals between consecutive R-wave sensed event signals received from the ventricular sensing channel 89, and the PR and / or RP intervals received between the P-wave sensed event signals and the R-wave sensed event signals. These intervals can be compared to the tachycardia detection intervals to detect non-sinus tachycardia. Tachycardia can be detected in a given cardiac chamber based on a threshold number of tachycardia detection intervals detected.

[0092] The therapy delivery circuit 84 may include an atrial pacing circuit 83 and a ventricular pacing circuit 85. Each pacing circuit 83, 85 may include charging circuitry, one or more charge storage devices (e.g., one or more low voltage holding capacitors), an output capacitor, and / or switching circuitry that controls when the one or more holding capacitors are charged and discharged across the output capacitor to deliver pacing pulses to a pacing electrode vector coupled to the respective pacing circuit 83, 85. The tip electrode 42 and the proximal housing-based electrode 24 may be coupled to the ventricular pacing circuit 85 as a bipolar cathode and anode pair to deliver ventricular pacing pulses, for example, upon expiration of an AV or VV pacing interval set by the control circuit 80 for providing atrial synchronized ventricular pacing and a substantially lower ventricular pacing rate.

[0093] The atrial pacing circuit 83 can be coupled to the distal shell-based electrode 22 and the proximal shell-based electrode 24 to deliver atrial pacing pulses. The control circuit 80 can set one or more atrial pacing intervals according to a programmed lower pacing rate or a temporarily lower rate set according to a pacing rate indicated by a rate-responsive sensor. If the atrial pacing interval expires before a P-wave sensed event signal is received from the atrial sensing channel 87, the atrial pacing circuit can be controlled to deliver an atrial pacing pulse. The control circuit 80 starts an AV pacing interval in response to the delivered atrial pacing pulse to provide synchronized multi-chamber pacing (e.g., dual-chamber or triple-chamber pacing).

[0094] The holding capacitors of the atrial or ventricular pacing circuits 83, 85 may be charged to a programmed pacing voltage amplitude and discharged for a programmed pacing pulse width by the therapy delivery circuit 84 in accordance with control signals received from the control circuit 80. For example, a pacing timing circuit included in the control circuit 80 may include a programmable digital counter that is set by a microprocessor of the control circuit 80 for controlling basic pacing time intervals associated with various single-chamber or multi-chamber pacing (e.g., dual-chamber or triple-chamber pacing) modes or anti-tachycardia pacing sequences. The microprocessor of the control circuit 80 may also set the amplitude, pulse width, polarity, or other characteristics of the cardiac pacing pulses that may be based on programmed values ​​stored in the memory 82.

[0095] The device 10 may include other sensors 90 for sensing signals from the patient for use in determining the need for and / or controlling the electrical stimulation therapy delivered by the therapy delivery circuit 84. In some examples, the sensor indicating the need for increased cardiac output may include a patient activity sensor, such as an accelerometer. An increase in the patient's metabolic demand due to increased activity as indicated by the patient activity sensor may be determined by the control circuit 80 for use in determining the sensor-indicated pacing rate.

[0096] Control parameters utilized by control circuit 80 for sensing cardiac events and controlling the delivery of pacing therapy may be programmed into memory 82 via telemetry circuit 88, which may also be described as a communication interface. Telemetry circuit 88 includes a transceiver and antenna for communicating with an external device such as a programmer or home monitor using radio frequency communications or other communication protocols. Control circuit 80 may use telemetry circuit 88 to receive downlink telemetry from an external device and to send uplink telemetry to an external device. In some cases, telemetry circuit 88 may be used to transmit / receive communication signals to / from another medical device implanted in a patient.

[0097] Fig. 9 7 is a three-dimensional perspective view of another leadless intracardiac medical device 710 that can be configured for calibrating pacing therapy and / or delivering pacing therapy for single-chamber or multi-chamber heart therapy (e.g., dual-chamber or triple-chamber heart therapy) according to another example. The device 710 can include a housing 730 having an outer sidewall 735 extending from a housing distal region 732 to a housing proximal region 734, shown as a cylindrical outer sidewall. The housing 730 can enclose an electronic circuit system configured to perform a single-chamber or multi-chamber heart therapy, including atrial and ventricular cardiac electrical signal sensing and pacing of the atrial chamber and the ventricular chamber. A delivery tool interface member 726 is shown on the housing proximal region 734.

[0098] The distal fixation and electrode assembly 736 may be coupled to the housing distal region 732. The distal fixation and electrode assembly 736 may include an electrically insulating distal member 772 coupled to the housing distal region 732. The tissue-piercing electrode assembly 712 extends away from the housing distal region 732, and the plurality of non-tissue-piercing electrodes 722 may be directly coupled to the insulating distal member 772. The tissue-piercing electrode assembly 712 extends in a longitudinal direction away from the housing distal region 732 and may be coaxial with the longitudinal center axis 731 of the housing 730.

[0099] The distal tissue piercing electrode assembly 712 can include an electrically insulating shaft 740 and a tip electrode 742 (e.g., a tissue piercing electrode). In some examples, the tissue piercing electrode assembly 712 is a movable fixing member including a helical shaft 740 and a distal cathode tip electrode 742. The helical shaft 740 can extend from a shaft distal region 743 to a shaft proximal region 741, which can be directly coupled to an insulating distal member 772. The helical shaft 740 can be coated with an electrically insulating material, such as polyparaxylene or other examples listed herein, to avoid sensing or stimulating cardiac tissue along the length of the shaft. The tip electrode 742 is at the shaft distal region 743 and can act as a cathode electrode for delivering ventricular pacing pulses and sensing ventricular electrical signals using a proximal housing-based electrode 724 as a return anode when the tip electrode 742 is advanced into the ventricular tissue. The proximal housing-based electrode 724 can be a ring electrode of the external housing 730 and can be defined by an uninsulated portion of the longitudinal sidewall 735. Other portions of the housing 730 that do not serve as electrodes may be used in conjunction with Figure 7 An electrically insulating material coating is described.

[0100] The use of two or more tissue-piercing electrodes (e.g., any type of tissue-piercing electrodes) that penetrate into the LV myocardium can be used for more localized pacing capture and can mitigate ventricular pacing spikes that affect capture of atrial tissue. In some embodiments, the plurality of tissue-piercing electrodes can include two or more dart-type electrode assemblies (e.g., Figure 7 The multiple tissue piercing electrodes may also be used for bipolar or multipolar pacing.

[0101] In some embodiments, the one or more tissue piercing electrodes (e.g., any type of tissue piercing electrode) that penetrate into the LV myocardium can be multipolar tissue piercing electrodes. The multipolar tissue piercing electrodes can include one or more electroactive elements and electro-isolating elements, which can enable bipolar or multipolar pacing from the one or more tissue piercing electrodes.

[0102] A plurality of non-tissue piercing electrodes 722 may be provided along the periphery of the insulating distal member 772, which is located at the periphery of the tissue piercing electrode assembly 712. The insulating distal member 772 may define a distally facing surface 738 of the device 710 and a circumferential surface 739 of the device 710 circumscribing the longitudinal sidewall 735 of the housing. The non-tissue piercing electrodes 722 may be formed of a conductive material such as titanium, platinum, iridium, or alloys thereof. In the illustrated embodiment, six non-tissue piercing electrodes 722 are radially spaced at equal distances along the periphery of the insulating distal member 772. However, two or more non-tissue piercing electrodes 722 may be provided.

[0103] The non-tissue piercing electrodes 722 can be discrete components that are each held within a corresponding recess 774 in the insulating member 772 that is sized and shaped to match the non-tissue piercing electrodes 722. In other examples, the non-tissue piercing electrodes 722 can each be an uninsulated exposed portion of a single-piece member mounted within or on the insulating distal member 772. The intermediate portion of the single-piece member that is not used as an electrode can be insulated by the insulating distal member 772, or if the intermediate portion is exposed to the surrounding environment, it can be coated with an electrically insulating coating, such as parylene, polyurethane, silicone, epoxy, or other insulating coating.

[0104] When tissue-piercing electrode assembly 712 is advanced into cardiac tissue, at least one non-tissue-piercing electrode 722 may be positioned against, in close contact with, or in operational proximity to the surface of cardiac tissue to deliver pulses and / or sense cardiac electrical signals generated by the patient's heart. For example, when tissue-piercing electrode assembly 712 is advanced into atrial tissue and through the central fiber body until distal tip electrode 742 is positioned in direct contact with ventricular tissue (e.g., ventricular myocardium and / or portions of the ventricular conduction system), non-tissue-piercing electrode 722 may be positioned in contact with right atrial endocardial tissue for pacing and sensing in the atrium.

[0105] The non-tissue piercing electrode 722 may be coupled to a therapy delivery circuit 84 and a sensing circuit 86 enclosed by a housing 730 (see Figure 8), to be used in conjunction with the proximal housing-based electrode 724 as a return anode as a cathode electrode for delivering atrial pacing pulses and sensing atrial electrical signals (e.g., P waves). The switch circuitry contained in the sensing circuit 86 can be activated under the control of the control circuit 80 to couple one or more of the non-tissue piercing electrodes to the atrial sensing channel 87. The distal non-tissue piercing electrodes 722 can be electrically isolated from each other so that each individual electrode of the electrodes 722 can be individually selected by the switch circuitry contained in the therapy delivery circuit 84 to serve as an atrial cathode electrode, either individually or in combination of two or more of the electrodes 722. The switch circuitry contained in the therapy delivery circuit 84 can be activated under the control of the control circuit 80 to couple one or more of the non-tissue piercing electrodes 722 to the atrial pacing circuit 83. Two or more of the non-tissue piercing electrodes 722 can be selected at one time to serve as multiple atrial cathode electrodes.

[0106] Certain non-tissue piercing electrodes 722 may be selected for atrial pacing and / or atrial sensing based on atrial capture threshold testing, electrode impedance, P-wave signal strength in the cardiac electrical signal, or other factors. For example, a single non-tissue piercing electrode 722 or any combination of two or more individual non-tissue piercing electrodes may be selected to serve as a cathode electrode that provides an optimal combination of low pacing capture threshold amplitude and relatively high electrode impedance to achieve reliable atrial pacing using minimal current consumption from the power supply 98.

[0107] In some cases, when the tissue-piercing electrode assembly 712 anchors the housing 730 at the implantation site, the distal-facing surface 738 can uniformly contact the atrial endocardial surface. In such cases, all of the electrodes 722 can be selected together to form an atrial cathode. Alternatively, every other electrode in the electrodes 722 can be selected together to form a multi-point atrial cathode with a higher electrical impedance, which is still evenly distributed along the distal-facing surface 738. Alternatively, a subset of one or more electrodes 722 along one side of the insulating distal member 772 can be selected to provide pacing at a desired location that achieves the lowest pacing capture threshold due to the relative position of the electrodes 722 to the atrial tissue being paced.

[0108] In other cases, depending on the positioning and orientation of the tissue piercing electrode assembly 712 into the heart tissue, the distally facing surface 738 can be oriented at an angle relative to the adjacent endocardial surface. In this case, one or more of the non-tissue piercing electrodes 722 can be positioned to be in closer contact with the adjacent endocardial tissue than other non-tissue piercing electrodes 722, which can be angled away from the endocardial surface. By providing multiple non-tissue piercing electrodes along the periphery of the insulating distal member 772, the angles of the tissue piercing electrode assembly 712 and the housing distal region 732 relative to the heart surface (e.g., the right atrial endocardial surface) may not necessarily be substantially parallel. Anatomical and positioning differences may cause distal-facing surface 738 to be angled or tilted relative to the endocardial surface, however, multiple non-tissue piercing electrodes 722 distributed along the periphery of insulating distal member 772 increase the likelihood of good contact between one or more electrodes 722 and adjacent cardiac tissue, thereby facilitating acceptable pacing thresholds and reliable cardiac event sensing using at least a subset of multiple electrodes 722. Contact or fixation circumferentially along the entire periphery of insulating distal member 772 may not be required.

[0109] The non-tissue piercing electrodes 722 are shown as each comprising a first portion 722a extending along a distally facing surface 738 and a second portion 722b extending along a circumferential surface 739. The first portion 722a and the second portion 722b can be continuous exposed surfaces such that the active electrode surface is wrapped around a peripheral edge 776 of the insulative distal member 772 that joins the distally facing surface 738 and the circumferential surface 739. The non-tissue piercing electrodes 722 can include one or more of the electrodes 722 along the distally facing surface 738, one or more electrodes along the circumferential surface 739, one or more electrodes each extending along both the distally facing surface 738 and the circumferential surface 739, or any combination thereof. The exposed surface of each of the non-tissue piercing electrodes 722 can be flush with the corresponding distally facing surface 738 and / or circumferential surface. In other examples, each of non-tissue-piercing electrodes 722 may have a raised surface that protrudes from insulative distal member 772. However, any raised surface of electrodes 722 may define a smooth or rounded non-tissue-piercing surface.

[0110] The distal fixation and electrode assembly 736 can seal the distal region of the housing 730 and can provide a basis for mounting the electrode 722 thereon. The electrode 722 can be referred to as a housing-based electrode. The electrode 722 can be carried by no shaft or other extension that extends an active electrode portion (such as a distal tip electrode 742 located at the distal tip of a helical shaft 740 extending away from the housing 730) away from the housing 730. Other examples of non-tissue-piercing electrodes coupled to the distal-facing and / or circumferential surfaces of the insulative distal member presented herein include a distal housing-based ring electrode 22 ( Figure 7 ), around the assembly 36 ( Figure 7 ) circumferentially extending distal shell-based ring electrodes, button electrodes, other shell-based electrodes, and other circumferential ring electrodes. Any non-tissue piercing electrodes located at the periphery of the central tissue piercing electrode directly connected to the distal insulating member can be provided to serve as cathode electrodes for delivering pacing pulses to adjacent cardiac tissue, individually, collectively, or in any combination. When ring electrodes, such as the distal ring electrode 22 and / or circumferential ring electrodes are provided, portions of the ring electrodes can be electrically insulated by a coating to provide a plurality of distributed non-tissue piercing electrodes along the distal-facing surface and / or circumferential surface of the insulating distal member.

[0111] The non-tissue piercing electrodes 722 and other examples listed above are expected to provide more reliable and effective atrial pacing and sensing than tissue piercing electrodes provided along the distal fixation and electrode assembly 736. The atrial cavity wall is relatively thin compared to the ventricular cavity wall. The tissue piercing atrial cathode electrode may extend too deep into the atrial tissue, resulting in unintentional, continuous or intermittent capture of the ventricular tissue. Due to the ventricular signal having a greater signal strength in the cardiac electrical signal received via the tissue piercing atrial cathode electrode that is physically closer to the ventricular tissue, the tissue piercing atrial cathode electrode may interfere with the sensed atrial signal. The tissue piercing electrode assembly 712 can be firmly anchored in the ventricular tissue to stabilize the implantation position of the device 710 and provide reasonable certainty that the tip electrode 742 is sensing and pacing in the ventricular tissue while the non-tissue piercing electrode 722 is reliably pacing and sensing in the atrium. When the device 710 is implanted in the target implant area 4 (e.g., such as Figure 1, ventricular septum), the tip electrode 742 can reach the left ventricular tissue to pace the left ventricle, while the non-tissue-piercing electrode 722 provides pacing and sensing in the right atrium. The length of the tissue-piercing electrode assembly 712 from the distal-facing surface 738 can be in the range of about 4 to about 8 mm to reach the left ventricular tissue. In some cases, the device 710 can achieve four-chamber pacing by delivering atrial pacing pulses from the atrial pacing circuit 83 through the non-tissue-piercing electrode 722 in the target implant area 4 to achieve bi-atrial (right atrium and left atrium) capture, and delivering ventricular pacing pulses from the ventricular pacing circuit 85 through the tip electrode 742 that advances from the target implant area 4 into the ventricular tissue to achieve bi-ventricular (right ventricle and left ventricle) capture.

[0112] Fig.10 shows an example using Figure 5 An illustrative method 600 of detecting atrial activity using an acoustic or motion detector 11 of a patient's heart, which atrial activity can be used to represent physiological response information. Specifically, method 600 can include detecting atrial contraction based on an analysis of a motion signal (e.g., provided by motion detector 11) that can be performed by an IMD implanted in the patient's heart. In some embodiments, the motion signal can be provided by an IMD implanted in a ventricle (e.g., right ventricle) of the patient's heart. Method 600 can include starting an atrial contraction detection delay period 630 when a ventricular activation event is identified. Method 600 can include starting an atrial contraction detection window 632 when the atrial contraction delay period expires. Method 600 can include analyzing the motion signal within the atrial contraction detection window.

[0113] The method 600 may include filtering the motion signal within the atrial contraction detection window; rectifying the filtered signal; and generating a derivative signal of the filtered and rectified motion signal within the atrial contraction detection window 634. The method 600 may include determining whether the magnitude of the derivative signal within the atrial contraction detection window exceeds a threshold 636. In response to determining that the magnitude of the derivative signal within the atrial contraction detection window exceeds the threshold (YES in 636), the method 600 may proceed to detecting atrial contraction 638. Otherwise (NO in 636), the method 600 may return to filtering, rectifying, and generating the derivative signal 634. Various techniques for using a motion detector that provides a motion signal can be described in U.S. Pat. No. 9,399,140 (Cho et al.), entitled “Atrial contraction detection by a ventricular leadless pacing device for atrio-synchronous ventricular pacing,” issued on July 26, 2016, which is incorporated herein by reference in its entirety.

[0114] As about Fig.11 As described, heart sounds (HS) can be detected and used to represent physiological response information. As described herein, the amplitude and / or relative time interval of one or more of the S1 to S4 heart sounds can be used to optimize the patient's hemodynamic response to CRT or other cardiac therapies including cardiac pacing and / or neural stimulation to achieve hemodynamic benefits. The first heart sound S1 corresponds to the beginning of ventricular systole. Ventricular systole begins when the action potential is conducted through the atrioventricular node (AV node) and rapidly depolarizes the ventricular myocardium. This event is distinguished by the QRS complex wave on the ECG. When the ventricle contracts, the pressure in the ventricle begins to rise, so that when the ventricular pressure exceeds the atrial pressure, the mitral valve and tricuspid valve between the ventricle and the atrium suddenly close. This valve closure can generate S1. S1 typically has a duration of about 150 milliseconds and a frequency of approximately about 20Hz to 250Hz. The amplitude of S1 can provide an alternative measure of LV contractility. Therefore, an increase in the S1 amplitude can be positively correlated with an improvement in LV contractility. Other measurements, such as the pre-ejection period measured from QRS onset to S1, can also be used as an alternative index of myocardial contractility.

[0115] Separation of mitral and tricuspid valve closure due to ventricular dyssynchrony can be observed as separate M1 and T1 peaks in the S1 signal. The merging of M1 (mitral valve closure sound) and T1 (tricuspid valve closure sound) can be used as an indicator of improved ventricular synchrony.

[0116] Typically, after the QRS complex of the ECG and the closure of the mitral valve, left ventricular pressure (LVP) rises sharply and continues to increase during the ventricular systole until the aortic and pulmonary valves open, ejecting blood into the aorta and pulmonary arteries. During the ejection phase, ventricular contraction typically continues to increase blood pressure in the ventricles and aorta and pulmonary arteries. As contraction decreases, blood pressure decreases until the aortic and pulmonary valves close.

[0117] The second heart sound S2 can be generated by closing the aortic and pulmonary valves near the end of the ventricular systolic period and the beginning of the ventricular diastolic period. Therefore, S2 can be related to the diastolic pressure in the aorta and the pulmonary artery. S2 usually has a duration of about 120ms and a frequency of about 25 to 350Hz. The time interval between S1-S2, that is, the S1 to S2 time interval can represent the contraction time interval (STI) corresponding to the ventricular isovolumetric contraction phase (pre-ejection phase) and the ejection phase of the cardiac cycle. This S1-S2 time interval can provide an alternative measure of stroke volume. In addition, the ratio of the pre-ejection phase (Q-S1) to the S1-S2 time can be used as an index of myocardial contractility.

[0118] The third heart sound S3 is associated with early passive diastolic filling of the ventricles, and the fourth heart sound S4 can be associated with late active filling of the ventricles due to atrial contraction. Typically, the third sound is difficult to hear in normal patients using a stethoscope, and the fourth sound is not usually heard in normal patients. During an examination using a stethoscope, the presence of the third and fourth heart sounds can indicate a pathological condition. The S3 and S4 heart sounds can be used to optimize pacing parameters due to their association with the diastolic function of the heart. Typically, these sounds will be minimized or disappear when optimal pacing parameters are identified. Other aspects of the S1 to S4 heart sounds and their timing that can be used in cardiac pacing parameter optimization are known to those of ordinary skill in the art.

[0119] Fig.11 800 is a flowchart of a method for optimizing pacing control parameters using heart sounds, according to one embodiment. The disclosed method may include one or more of the blocks shown in flowchart 800. Other examples of optimizing cardiac therapy using heart sounds are generally described in U.S. Pat. No. 9,643,0134, entitled “System and method for pacing parameter optimization using heart sounds,” issued May 9, 2017, which is incorporated herein by reference in its entirety.

[0120] The pacing parameter optimization method can be initiated at box 802. The optimization process can be initiated in response to a user command received via an external programmer. The user can initiate the HS-based optimization procedure using an external programmer or a networked computer at the time of initial IMD implantation or during an in-office follow-up visit, or during a remote patient monitoring session. Additionally or alternatively, the process shown in flowchart 800 can be an automated process that is initiated periodically or in response to sensing a need for therapy delivery or therapy adjustment based on sensed physiological signals (which can include sensed HS signals).

[0121] At box 804, a pacing control parameter to be optimized is selected. The control parameter may be a timing-related parameter, such as an AV interval or a VV interval. A pacing vector is another control parameter that may be selected for optimization at box 804. For example, when using a multipolar lead such as a coronary sinus lead, multiple bipolar or unipolar pacing vectors may be selected for pacing in a given cardiac chamber. The pacing site associated with a particular pacing vector may have a significant impact on the hemodynamic benefit of the pacing therapy. As such, a pacing vector is one pacing control parameter that may be optimized using the methods described herein.

[0122] A pacing sequence is initiated at box 806 using the initial parameter settings for the test parameters selected at box 804. In one embodiment, the AV interval is being optimized and ventricular pacing is delivered at the initial AV interval setting. It should be understood that the initial AV interval setting can be selected at box 806 by first measuring the intrinsic AV interval of a patient with intact AV conduction (i.e., no AV block). The initial AV interval can be a default pacing interval, a last programmed AV interval, or a minimum or maximum AV interval to be tested. Alternatively, if the VV interval is selected for optimization, the intrinsic interventricular conduction time can be measured first, and the paced VV interval can be iteratively adjusted starting with a VV interval that is longer, shorter, or approximately equal to the intrinsic VV conduction time.

[0123] An iterative process for adjusting the selected test parameter to at least two different settings is performed. The parameters can be adjusted to the different settings in any desired order (e.g., ascending, descending, random, etc.). For example, during adjustment of the AV interval, an initial AV interval can be set to be just longer than or approximately equal to the measured intrinsic AV conduction time, and then the initial AV interval is iteratively reduced to a minimum AV interval test setting. During pacing using each pacing parameter setting, an HS signal is acquired at box 808. At box 812, the iterative process advances to the next test parameter setting until all test parameter settings have been applied and an HS signal has been recorded for each setting, as determined at box 810.

[0124] HS signals may be acquired for multiple cardiac cycles to enable ensemble averaging or averaging of HS parameter measurements acquired from separate cardiac cycles. It should be understood that amplification, filtering, rectification, noise removal techniques, or other signal processing steps may be used to improve the signal-to-noise ratio of the HS signal, and that these steps may be different for each of the acquired heart sounds, which may include any or all types of heart sounds.

[0125] At box 814, for each test parameter setting, at least one HS parameter measurement is determined from the recorded HS signal. For example, an IMD processor contained in the programmer or an external processor, or a combination of both, can perform the HS signal analysis described herein. In one embodiment, at box 814, S1 and S2 are recorded and HS parameters are measured using the S1 and S2 signals. For example, the amplitude of S1, the V-S2 interval (wherein the V event can be a V paced or sensed R wave), and the S1-S2 interval are measured. The presence of S3 and / or S4 can be additionally noted, or these signals can be measured to determine the relevant parameters. HS signal parameters are determined for at least two different test parameter settings (e.g., at least two different AV intervals, two or more different VV intervals, or two or more different pacing vectors).

[0126] At box 818, a trend is determined for each HS parameter determined at box 810 as a function of the pacing parameter test settings. In one embodiment, a trend is determined for each of the V-S2 interval, the S1 amplitude, and the S1-S2 interval. Other embodiments may include determining the separation of the M1 and T1 sounds during the S1 signal. Based on the trend of one or more HS parameters relative to the varying pacing control parameters, at box 820, the processor may automatically identify the optimal pacing parameter settings. Additionally or alternatively, at box 822, the HS trends are reported and displayed on an external device such as a programmer or at a remote networked computer.

[0127] If the pacing parameter tested is, for example, a pacing site or a pacing vector when positioning a multipolar electrode along a cardiac chamber (e.g., a quadripolar lead along the LV), the pacing site or vector can be selected based on maximizing a HS-based surrogate for ventricular contractility. In one embodiment, the amplitude of S1 is used as a surrogate for ventricular contractility, and the pacing site or vector associated with the maximum S1 is identified at block 820 as the optimal pacing vector setting.

[0128] Determining the trend of each HS parameter at block 818 may include determining whether the V-S2 interval trend exhibits an abrupt change in slope, such as from a substantially flat trend to a decreasing trend. The AV interval associated with the abrupt change in the V-S2 interval trend may be identified as the optimal AV interval setting. The optimal AV interval may be further identified based on other HS trends, such as the maximum S1 amplitude and / or the maximum S1-S2 interval.

[0129] In some embodiments, the automatically identified optimal pacing parameter settings may also be automatically programmed in the IMD at block 824. In other embodiments, a clinician or user reviews the reported HS data and the suggested one or more pacing parameter settings and may accept the suggested settings or select another setting based on the HS data.

[0130] The HS sensing module or circuit system can be operably coupled to the control circuit 80 ( Figure 8 ) and is configured to receive analog signals from a HS sensor for sensing one or more of these heart sounds. For example, the HS sensing module may include one or more "channels" configured to specifically sense specific heart sounds based on the frequency, duration, and timing of the heart sounds. For example, the ECG / EGM sensing circuit system can be used by the control circuit 80 to set the HS sensing window used by the HS sensing module for sensing heart sounds. The HS sensing module may include one or more sensing amplifiers, filters, and rectifiers for optimizing the signal-to-noise ratio of the heart sound signal. Separate and unique amplification and filtering characteristics can be provided for sensing each of the S1 to S4 sounds to improve signal quality as needed.

[0131] Bioimpedance or intracardiac impedance can be measured and used to represent physiological response information. For example, any IMD in the IMD described herein can measure intracardiac impedance signals by injecting current and measuring the voltage between electrodes (e.g., selected electrodes) of an electrode vector configuration. For example, the IMD can measure impedance signals by injecting current (e.g., non-pacing threshold current) between a first electrode (e.g., RV electrode) and an electrode in the RV positioned near the tricuspid valve and measuring the voltage between the first electrode and the second electrode. Another vector that can be used is from the LV electrode to the RV electrode. It will be recognized that other vector pair configurations can be used for stimulation and measurement. Impedance can be measured between any set of electrodes covering the tissue or cardiac chamber of interest. Therefore, an individual can inject current and measure voltage to calculate impedance on the same two electrodes (bipolar configuration), or inject current and measure voltage on two separate pairs of electrodes (e.g., one pair for current injection, and one pair for voltage sensing), so it is a quadruple configuration. For a quadruple electrode configuration, the current injection electrode and the voltage sensing electrode can be in a straight line (or closely parallel) with each other, and the voltage sensing electrode can be located within the current sensing field. For example, if a current is injected between the SVC coil electrode and the RV tip electrode, the voltage sensing can be between the RV coil electrode and the RV ring electrode. In such embodiments, the VfA lead can be used for LV cardiac therapy or sensing. The impedance vector can be configured to include a specific anatomical region of interest, such as the atria or ventricles.

[0132] The illustrative methods and / or apparatus described herein can monitor one or more electrode vector configurations. In addition, multiple impedance vectors can be measured simultaneously and / or periodically relative to one another. In at least one embodiment, the illustrative methods and / or apparatus can use impedance waveforms to obtain selection data (e.g., find applicable reference points to allow measurements to be extracted from such waveforms, etc.) to optimize CRT.

[0133] As used herein, the term "impedance signal" is not limited to the raw impedance signal. It should be noted that the raw impedance signal may be processed, normalized, and / or filtered (e.g., to remove artifacts, noise, static electricity, electromagnetic interference (EMI), and / or extraneous signals) to provide an impedance signal. In addition, the term "impedance signal" may include various mathematical derivatives thereof, including the real and imaginary parts of the impedance signal, an impedance-based conductance signal (i.e., the inverse or reciprocal of the impedance), and the like. In other words, the term "impedance signal" may be understood to include a conductance signal, i.e., a signal that is the inverse of the impedance signal.

[0134] In one or more embodiments of the methods and / or devices described herein, various patient physiological parameters (e.g., intracardiac impedance, heart sounds, cardiac cycle intervals such as RR intervals, etc.) can be monitored to obtain selected data to optimize CRT (e.g., setting AV and / or VV delays, such as by using and / or measuring the first-order derivative of impedance dZ / dt to optimize cardiac contractility, selecting a pacing site, selecting a pacing vector, lead placement, or assessing pacing capture from an electrical and mechanical perspective (e.g., electrical capture may not mean mechanical capture, and heart sounds and impedance can help assess whether electrical stimulation has captured the heart by looking at mechanical information from heart sounds and impedance), selecting an effective electrode vector configuration for pacing, etc.). For example, an intracardiac impedance signal between two or more electrodes can be monitored to provide such optimization.

[0135] Fig.12 An example of a method 850 for obtaining selection data for one of the device parameter options (e.g., one of the selectable device parameters that can be used to optimize CRT, such as potential AV delay that can be an optimal parameter) is shown. Other examples of using heart sounds to optimize cardiac therapy are generally described in U.S. Patent No. 9,707,399, entitled "Cardiac resynchronization therapy optimization based on intracardiac impedance and heart sounds," issued on July 18, 2017, which is incorporated herein by reference in its entirety.

[0136] As shown, pacing therapy is delivered using one of a plurality of device options (box 852) (e.g., the plurality of device parameter options may be selected, determined, and / or calculated AV delays, such as percentages of intrinsic AV delay, e.g., 40% intrinsic AV delay, 50% intrinsic AV delay, 60% intrinsic AV delay, 70% intrinsic AV delay, 80% intrinsic AV delay, etc.). For the device parameter option for pacing (box 852), selection data is acquired at each of a plurality of electrode vector configurations (e.g., intracardiac impedance is monitored over a plurality of cardiac cycles and selection data is extracted using such impedance signals). As indicated by decision box 854, if selection data has not yet been acquired from all desired electrode vector configurations, a loop for acquiring selection data is repeated (e.g., the loop shown by boxes 858, 860, 862, and 864). If selection data has been acquired from all desired electrode vector configurations, therapy is delivered using another different device parameter option (box 856), and the loop is repeated. Fig.12method 850 (e.g., for different device parameter options) until selection data has been acquired for all of the different device parameter options (e.g., selection data is collected at each electrode vector configuration in a plurality of electrode vector configurations for each of the different device parameter options).

[0137] As shown in a repeating loop of acquiring selected data for each of the desired electrode vector configurations (e.g., blocks 858, 860, 862, and 864), one of a plurality of electrode vector configurations is selected for acquiring selected data (block 858). For the selected electrode vector configuration, a time reference point associated with at least a portion of the systolic portion of at least one cardiac cycle and / or a time reference point associated with at least a portion of the diastolic portion of at least one cardiac cycle is acquired (block 860) (e.g., such as using heart sounds, analyzing minimum and maximum values ​​of an impedance signal, applying an algorithm based on a physiological parameter such as an RR interval, etc.). For example, a time reference point associated with the systolic and / or diastolic portion of the cardiac cycle may be acquired, a time reference point associated with one or more defined segments within the systolic and / or diastolic portion of the cardiac cycle may be acquired, and / or a time reference point within or associated with one or more points and / or portions of the systolic and / or diastolic portion of the cardiac cycle may be acquired. Still further, for example, time reference points may be acquired that are associated with only the systolic portion or only the diastolic portion of the cardiac cycle, time reference points may be acquired that are associated with one or more defined segments only within the systolic portion or the diastolic portion of the cardiac cycle, and / or time reference points may be acquired within or associated with one or more points and / or portions of only the systolic portion or only the diastolic portion of the cardiac cycle. In other words, reference points may be acquired that are associated with both the systolic and diastolic portions of the cardiac cycle or with only one of such portions of the cardiac cycle. Furthermore, for example, such reference points may represent or indicate measurement windows and / or time periods (e.g., intervals, points, etc.) at or during which intracardiac impedance may be measured for the analysis described herein.

[0138] In approximately the same time frame (e.g., approximately simultaneously with the acquired reference points), an intracardiac impedance signal is acquired at the selected electrode vector configuration (block 862). Using the acquired reference points and the acquired intracardiac impedance signal, measurements from the impedance signal are extracted based on the temporal reference points (block 864) (e.g., an integral of the impedance signal in a measurement window defined between the reference points, a maximum slope of the impedance signal in a measurement window defined between the reference points, the time between the reference points, the maximum impedance at the reference points, etc.). One or more of such measurements may be comparable to expected values ​​for such measurements, thereby allowing a determination to be made as to whether the measurements may indicate that a device parameter option may be an effective device parameter for optimizing therapy (e.g., a scoring algorithm may be used to determine whether a device parameter option may be an optimal parameter based on whether a plurality of such measurements meet certain criteria or thresholds).

[0139] Determine measurement data for each device parameter in the device parameter options for at least one cardiac cycle (e.g., Fig.12 In one or more embodiments, such measurement data is acquired for a plurality of cardiac cycles. The cardiac cycle during which the measurement data is acquired can be any suitable cardiac cycle. In one or more embodiments, the selected cardiac cycle during which the measurement data is acquired is based on a respiratory cycle. In at least one embodiment, the measurement data is acquired during a cardiac cycle that occurs at the end of a respiratory cycle (e.g., near the end of exhalation).

[0140] Fig.13 An illustrative system 100 is depicted that includes an electrode device 110, a display device 130, and a computing device 140. The electrode device 110 as shown includes a plurality of electrodes that are incorporated into or contained within a band that is wrapped around the chest or torso of a patient 120. The electrode device 110 is operably connected to the computing device 140 (e.g., via one or wired electrical connections, wirelessly, etc.) to provide electrical signals from each of the electrodes to the computing device 140 for analysis, evaluation, etc. An illustrative electrode device may be described in U.S. Patent No. 9,320,446, issued on April 26, 2016, entitled “Bioelectric Sensor Device and Methods,” which is incorporated herein by reference in its entirety. In addition, reference will be made to Figure 14-15 Illustrative electrode device 110 is described in further detail.

[0141] Although not described herein, the illustrative system 100 may further include an imaging device. The imaging device may be any type of imaging device configured to image at least a portion of a patient in a non-invasive manner or provide an image of at least a portion of the patient. For example, the imaging device may provide an image of the patient without using any components or parts that can be positioned within the patient's body, except for non-invasive tools such as contrast solutions. It should be understood that the illustrative systems, methods, and interfaces described herein may further use imaging devices to provide non-invasive assistance to a user (e.g., a physician) to calibrate and / or deliver VfA pacing therapy, to position and place a device to deliver VfA cardiac pacing therapy, and / or to position or select a pacing electrode or pacing vector close to the patient's heart in conjunction with an assessment of atrial to ventricular pacing therapy for atrial to ventricular pacing therapy.

[0142] For example, the illustrative systems, methods, and interfaces can provide image-guided navigation that can be used to navigate leads including leadless devices, electrodes, leadless electrodes, wireless electrodes, catheters, etc. within a patient's body, while also providing noninvasive cardiac therapy assessments that include determining whether atrial to ventricular (VfA) pacing settings are optimal, or determining whether one or more selected parameters (e.g., selected position information (e.g., position information for targeting an electrode to a specific location in the left ventricle)) are optimal. Illustrative systems and methods using imaging devices and / or electrode devices may be described in U.S. Patent Publication No. 2014 / 0371832, filed on June 12, 2013, and entitled “Implantable Electrode Location Selection,” U.S. Patent Publication No. 2014 / 0371833, filed on June 12, 2013, and entitled “Implantable Electrode Location Selection,” U.S. Patent Publication No. 2014 / 0323892, filed on March 27, 2014, and entitled “Systems, Methods, and Interfaces for Identifying Effective Electrodes,” U.S. Patent Publication No. 2014 / 0323893, filed on March 27, 2014, and entitled “Systems, Methods, and Interfaces for Identifying Optical-Electrical Vectors,” and U.S. Patent Publication No. 2014 / 0371834, filed on March 27, 2014, and entitled “Systems, Methods, and Interfaces for Identifying Optical-Electrical Vectors,” and U.S. Patent Publication No. 2014 / 0371835, filed on June 12, 2013, and entitled “Systems, Methods, and Interfaces for Identifying Optical-Electrical Vectors,” and U.S. Patent Publication No. 2014 / 0371836, filed on June 12, 2013, and entitled “Systems, Methods, and Interfaces for Identifying Vectors), each of which is incorporated herein by reference in its entirety.

[0143] Illustrative imaging devices can be configured to capture x-ray images and / or any other alternative imaging modalities. For example, the imaging device can be configured to use the following captured images or image data: isocentric fluoroscopy, biplane fluoroscopy, ultrasound, computed tomography (CT), multi-slice computed tomography (MSCT), magnetic resonance imaging (MRI), high frequency ultrasound (HIFU), optical coherence tomography (OCT), intravascular ultrasound (IVUS), two-dimensional (2D) ultrasound, three-dimensional (3D) ultrasound, four-dimensional (4D) ultrasound, intraoperative CT, intraoperative MRI, etc. Further, it should be understood that the imaging device can be configured to capture multiple continuous images (e.g., continuously) to provide video frame data. In other words, multiple images extracted over time using the imaging device can provide video frames or motion pictures, data. In addition, images can also be obtained and displayed in two dimensions, three dimensions, or four dimensions. In a more advanced form, the four-dimensional surface reproduction of the heart or other areas of the body can also be achieved by combining cardiac data or other soft tissue data from images captured by MRI, CT or echocardiography modalities or preoperative image data. Image datasets from hybrid modalities (such as positron emission tomography (PET) combined with CT, or single photon emission computed tomography (SPECT) combined with CT) can also provide functional image data superimposed on the anatomical data, for example, for navigating a therapeutic device approaching a target location within the heart or other region of interest (e.g., such as a location within the left ventricle, including a selected location within the high posterior base and / or septal region of the left ventricular cavity).

[0144] Systems and / or imaging devices that may be used in conjunction with the illustrative systems and methods described herein may be described in U.S. Patent Application Publication No. 2005 / 0008210 to Evron et al., published on January 13, 2005, U.S. Patent Application Publication No. 2006 / 0074285 to Zarkh et al., published on April 6, 2006, U.S. Patent Application Publication No. 2011 / 0112398 to Zarkh et al., published on May 12, 2011, U.S. Patent Application Publication No. 2013 / 0116739 to Brada et al., published on May 9, 2013, U.S. Patent Application Publication No. 2013 / 0116739 to Brada et al., published on December 27, 2005, No. 6,980,675 to Okerlund et al., issued October 23, 2007; No. 7,286,866 to Okerlund et al., issued December 11, 2011; No. 7,308,297 to Reddy et al., issued December 11, 2011; No. 7,308,299 to Burrell et al., issued December 11, 2011; No. 7,321,677 to Evron et al., issued January 22, 2008; No. 7,346,381 to Okerlund et al., issued March 18, 2008; No. 7,454,247 to Burrell et al., issued November 18, 2008; No. 8, Vass et al., U.S. Pat. No. 7,499,743, issued on March 3, 2009, U.S. Pat. No. 7,565,190, issued on July 21, 2009, U.S. Pat. No. 7,587,074, issued on September 8, 2009, U.S. Pat. No. 7,599,730, issued on October 6, 2009, Vass et al., U.S. Pat. No. 7,613,500, issued on November 3, 2009, Zarkh et al., U.S. Pat. No. 7,742,629, issued on June 22, 2010, Okerlund et al., issued on June 29, 2010, No. 7,747,047 to und et al., U.S. Patent No. 7,778,685 to Evron et al., issued on August 17, 2010, U.S. Patent No. 7,778,686 to Vass et al., issued on August 17, 2010, U.S. Patent No. 7,813,785 to Okerlund et al., issued on October 12, 2010, U.S. Patent No. 7,996,063 to Vass et al., issued on August 9, 2011, U.S. Patent No. 8,060,185 to Hunter et al., issued on November 15, 2011, and U.S. Patent No. 8,401,786 to Verard et al., issued on March 19, 2013.No. 616, each of which is incorporated herein by reference in its entirety.

[0145] The display device 130 and the computing device 140 can be configured to display and analyze data, such as electrical signals (e.g., electrocardiogram data), cardiac information representing one or more of mechanical heart function and electrical heart function (e.g., only mechanical heart function, only electrical heart function, or both mechanical heart function and electrical heart function), etc. The cardiac information can include, for example, electrical heterogeneity information or electrical asynchrony information, alternative electrical activation information or data, etc., which is generated using electrical signals acquired, monitored, or collected by the electrode device 110. In at least one embodiment, the computing device 140 can be a server, a personal computer, or a tablet computer. The computing device 140 can be configured to receive input from the input device 142 and transmit output to the display device 130. In addition, the computing device 140 may include a data storage device that may enable access to processing programs or routines and / or one or more other types of data, such as for calibrating and / or delivering pacing therapy to drive a graphical user interface configured to assist a user in non-invasively assisting in the placement of a targeted pacing device, and / or for evaluating pacing therapy at the location (e.g., the location of an implanted electrode for pacing, the location of pacing therapy delivered by a particular pacing vector, etc.).

[0146] The computing device 140 may be operatively coupled to the input device 142 and the display device 130, e.g., to transfer data to and from each of the input device 142 and the display device 130. For example, the computing device 140 may be electrically coupled to each of the input device 142 and the display device 130 using, e.g., an analog electrical connection, a digital electrical connection, a wireless connection, a bus-based connection, a network-based connection, an Internet-based connection, etc. As further described herein, a user may provide input to the input device 142 to manipulate or modify one or more graphical depictions displayed on the display device 130, and to view and / or select one or more pieces of information related to cardiac therapy.

[0147] Although, as depicted, the input device 142 is a keyboard, it is to be understood that the input device 142 may include any device capable of providing input to the computing device 140 to perform the functions, methods, and / or logic described herein. For example, the input device 142 may include a mouse, a trackball, a touch screen (e.g., a capacitive touch screen, a resistive touch screen, a multi-touch touch screen, etc.), etc. Similarly, the display device 130 may include any device capable of displaying information to a user, such as a graphical user interface 132, which includes cardiac information, text instructions, a graphical depiction of electrical activation information, a graphical depiction of the anatomical structure of the human heart, an image or graphical depiction of a patient's heart, a graphical depiction of a leadless pacing device used to calibrate and / or deliver pacing therapy, a graphical depiction of a leadless pacing device positioned or placed to provide VfA pacing therapy, a graphical depiction of the location of one or more electrodes, a graphical depiction of a human torso, an image or graphical depiction of a patient's torso, a graphical depiction or actual image of implanted electrodes and / or leads, etc. Further, the display device 130 may include a liquid crystal display, an organic light emitting diode screen, a touch screen, a cathode ray tube display, etc.

[0148] The processing programs or routines stored and / or executed by the computing device 140 may include programs or routines for computational mathematics, matrix mathematics, dispersion determination (e.g., standard deviation, variance, range, interquartile range, mean absolute difference, mean absolute deviation, etc.), filtering algorithms, maximum determination, minimum determination, threshold determination, moving window algorithms, decomposition algorithms, compression algorithms (e.g., data compression algorithms), calibration algorithms, image construction algorithms, signal processing algorithms (e.g., various filtering algorithms, Fourier transforms, fast Fourier transforms, etc.), normalization algorithms, comparison algorithms, vector mathematics, or any other processing required to implement one or more of the illustrative methods and / or processes described herein. The data stored and / or used by the computing device 140 may include, for example, electrical signal / waveform data from the electrode device 110, deviation signals, windowed deviation signals, locations or portions of various signals, electrical activation times from the electrode device 110, graphics (e.g., graphical elements, icons, buttons, windows, dialog boxes, drop-down menus, graphic areas, graphic regions, 3D graphics, etc.), graphical user interfaces, results of one or more processing programs or routines employed in accordance with the present disclosure (e.g., electrical signals, cardiac information, etc.), or any other data necessary to perform one and / or more processes or methods described herein.

[0149] In one or more embodiments, the illustrative systems, methods, and interfaces may be implemented using one or more computer programs executed on a programmable computer (e.g., a computer including, for example, processing capabilities, data storage devices (e.g., volatile or non-volatile memory and / or storage elements), input devices, and output devices). The program code and / or logic described herein may be applied to input data to perform the functionality described herein and generate desired output information. The output information may be applied as input to one or more other devices and / or methods as described herein or to be applied in a known manner.

[0150] Any programmable language (e.g., a high-level program and / or object-oriented programming language suitable for communicating with a computer system) may be used to provide one or more programs for implementing the systems, methods, and / or interfaces described herein. For example, any such program may be stored on any suitable device, such as a storage medium, that can be read by a general or special program running on a computer system (e.g., including a processing device) for configuring and operating the computer system to execute the program described herein when read by a suitable device. In other words, in at least one embodiment, the illustrative system, method, and / or interface may be implemented using a computer-readable storage medium configured with a computer program, wherein the storage medium so configured causes the computer to operate in a specific and predefined manner to perform the functions described herein. In addition, in at least one embodiment, the illustrative system, method, and / or interface may be described as being implemented by logic (e.g., object code) encoded in one or more non-transitory media, the logic comprising code for execution, and when executed by a processor, operable to perform operations such as the methods, processes, and / or functions described herein.

[0151] The computing device 140 can be, for example, any fixed or mobile computer system (e.g., a controller, a microcontroller, a personal computer, a microcomputer, a tablet computer, etc.) and can generally be described as including a processing circuit system. The exact configuration of the computing device 140 is not limiting, and substantially any device that can provide suitable computing power and control capabilities (e.g., graphics processing, etc.) can be used. As described herein, a digital file can be any medium (e.g., volatile or non-volatile memory, CD-ROM, punch card, magnetic recordable medium such as a disk or tape, etc.) containing digital bits (e.g., encoded in binary, ternary) that can be read and / or written by the computing device 140 described herein. Moreover, as described herein, a file in a user-readable format can be any representation of data (e.g., ASCII text, binary numbers, hexadecimal numbers, decimal numbers, graphics, etc.) that can be presented on any medium (e.g., paper, display, etc.) that can be read and / or understood by a user.

[0152] In view of the above, it will be apparent that the functions described in one or more embodiments of the present disclosure may be implemented in any manner known to those skilled in the art. Thus, the computer language, computer system, or any other software / hardware to be used to implement the processes described herein should not limit the scope of the systems, processes, or programs described herein (e.g., the functions provided by such systems, processes, or programs).

[0153] The electrical activation time of the patient's heart can be used to assess the patient's cardiac condition and / or to calibrate, deliver, or assess atrium-to-ventricle (VfA) cardiac therapy to be delivered or being delivered to the patient. Figure 13-15 The electrode device 110 shown in FIG. 1 is used to monitor or determine surrogate electrical activation information or data of one or more regions of the patient's heart. The illustrative electrode device 110 can be configured to measure body surface potentials of the patient 120 , and more specifically, to measure torso-surface potentials of the patient 120 .

[0154] like Fig.14 , an illustrative electrode device 110 may include a collection or array of electrodes 112, a strip 113, and an interface / amplifier circuit system 116. In at least one embodiment, portions of an electrode collection may be used, wherein the portions correspond to specific locations on a patient's heart. Electrodes 112 may be attached or coupled to strips 113, and strips 113 may be configured to wrap around the torso of a patient 120 such that electrodes 112 surround the patient's heart. As further illustrated, electrodes 112 may be positioned around the patient 120, including posterior, lateral, posterior lateral, anterolateral, and anterior locations of the torso of the patient 120.

[0155] Further, the electrodes 112 may be electrically connected to the interface / amplifier circuitry 116 via a wired connection 118. The interface / amplifier circuitry 116 may be configured to amplify signals from the electrodes 112 and provide the signals to the computing device 140. Other illustrative systems may use a wireless connection (e.g., as a data channel) to transmit signals sensed by the electrodes 112 to the interface / amplifier circuitry 116, and in turn to the computing device 140. For example, the interface / amplifier circuitry 116 may be electrically coupled to each of the computing device 140 and the display device 130 using, for example, an analog electrical connection, a digital electrical connection, a wireless connection, a bus-based connection, a network-based connection, an Internet-based connection, etc.

[0156] Despite Fig.14In some examples, the electrode device 110 includes a strip 113, but in other examples, any of a variety of mechanisms (e.g., tape or adhesive) can be used to assist in the spacing and placement of the electrodes 112. In some examples, the strip 113 can include elastic, tape strips, or cloth. In other examples, the electrodes 112 can be placed separately on the torso of the patient 120. Further, in other examples, the electrodes 112 (e.g., arranged in an array) can be part of or positioned within a patch, vest, and / or other means of securing the electrodes 112 to the torso of the patient 120.

[0157] The electrodes 112 can be configured to surround the heart of the patient 120 and record or monitor electrical signals associated with the depolarization and repolarization of the heart after the signals have propagated through the torso of the patient 120. Each of the electrodes 112 can be used in a monopolar configuration to sense a torso-surface potential that reflects the cardiac signal. The interface / amplifier circuit system 116 can also be connected to a return electrode or an indifferent electrode (not shown) that can be used in combination with each electrode 112 for monopolar sensing. In some instances, there can be about 12 to about 50 electrodes 112 spatially distributed around the torso of the patient. Other configurations can have more or fewer electrodes 112.

[0158] The computing device 140 may record and analyze electrical activity (e.g., trunk-surface potential signals) sensed by the electrodes 112 and amplified / conditioned by the interface / amplifier circuitry 116. The computing device 140 may be configured to analyze the signals from the electrodes 112 to provide anterior and posterior electrode signals as will be further described herein and in lieu of cardiac electrical activation times, e.g., representing actual or local electrical activation times of one or more regions of the patient's heart. The computing device 140 may be configured to analyze the signals from the electrodes 112 to provide anterior septal electrode signals as will be further described herein and in lieu of cardiac electrical activation times, e.g., representing actual or local electrical activation times of one or more anterior septal regions of the patient's heart, e.g., for use in calibrating, delivering, and / or evaluating VfA pacing therapy. Further, the electrical signal measured at the left anterior surface location of the patient's torso may represent or replace the electrical signal of the left anterior left ventricular region of the patient's heart, the electrical signal measured at the left lateral surface location of the patient's torso may represent or replace the electrical signal of the left lateral left ventricular region of the patient's heart, the electrical signal measured at the left posterior surface location of the patient's torso may represent or replace the electrical signal of the posterior left ventricular region of the patient's heart, and the electrical signal measured at the posterior surface location of the patient's torso may represent or replace the electrical signal of the left posterior ventricular region of the patient's heart. In one or more embodiments, the measurement of activation time may be performed by measuring the time period between the onset of cardiac depolarization (e.g., the onset of a QRS complex) and an appropriate reference point (e.g., a peak, minimum, minimum slope, maximum slope, zero crossing, threshold crossing, etc.).

[0159] Additionally, computing device 140 may be configured to provide a graphical user interface depicting alternative electrical activation times obtained using electrode device 110. The illustrative systems, methods, and / or interfaces may non-invasively use electrical information collected using electrode device 110 to assess a patient's cardiac condition and / or to calibrate, deliver, or assess VfA pacing therapy to be delivered or being delivered to a patient.

[0160] Fig.15 Another illustrative electrode device 110 is shown that includes a plurality of electrodes 112 that are configured to surround the heart of a patient 120 and record or monitor electrical signals associated with depolarization and repolarization of the heart after the signals have propagated through the torso of the patient 120. The electrode device 110 can include a vest 114 to which the plurality of electrodes 112 can be attached or to which the electrodes 112 can be coupled. In at least one embodiment, the plurality of electrodes 112 or an array of the electrodes can be used to collect electrical information, such as surrogate electrical activation times.

[0161] and Fig.14 Similar to the electrode device 110, Fig.13The electrode device 110 may include an interface / amplifier circuit system 116 electrically coupled to each of the electrodes 112 via a wired connection 118 and configured to transmit signals from the electrodes 112 to a computing device 140. As shown, the electrodes 112 may be distributed over the torso of the patient 120, including, for example, the anterior surface, the lateral surface, the posterolateral surface, the anterior lateral surface, and the posterior surface of the torso of the patient 120.

[0162] The vest 114 can be formed of fabric, wherein the electrodes 112 are attached to the fabric. The vest 114 can be configured to maintain the positioning and spacing of the electrodes 112 on the torso of the patient 120. Further, the vest 114 can be marked to assist in determining the position of the electrodes 112 on the surface of the torso of the patient 120. In one or more embodiments, the vest 114 can include about 17 or more front electrodes that can be positioned near the front torso of the patient, and about 39 or more rear electrodes that can be positioned near the front torso of the patient. In some instances, although there can be about 25 electrodes 112 to about 256 electrodes 112 distributed around the torso of the patient 120, other configurations can have more or fewer electrodes 112.

[0163] As described herein, the electrode device 110 can be configured to measure electrical information (e.g., electrical signals) representing different regions of the patient's heart. For example, activation times of different regions of the patient's heart can be estimated from surface electrocardiogram (ECG) activation times measured using surface electrodes proximate to surface regions corresponding to different regions of the patient's heart. In at least one instance, activation times of an anterior septum region of the patient's heart can be estimated using surface ECG activation times measured using surface electrodes proximate to surface regions corresponding to an anterior septum region of the patient's heart. That is, a portion of a set of electrodes 112, rather than the entire set, can be used to generate activation times corresponding to specific locations of the patient's heart corresponding to portions of the electrode set.

[0164] The illustrative systems, methods, and interfaces may be used to provide non-invasive assistance to a user in assessing a patient's cardiac health or status and / or assessing a cardiac therapy such as atrium-to-ventricle (VfA) pacing therapy (e.g., currently delivered to a patient during or after implantation) using the electrode device 110. In addition, the illustrative systems, methods, and interfaces may be used to assist a user in configuring or calibrating a cardiac therapy (e.g., VfA pacing therapy) to be delivered or being delivered to a patient.

[0165] VfA pacing can be described as providing synchronized homogeneous activation of the ventricles of the heart. As an example, patients with atrioventricular (AV) block or prolonged AV timing that may lead to heart failure, who otherwise have a complete (e.g., normal) QRS, can benefit from VfA pacing therapy. In addition, as an example, VfA pacing can provide beneficial activation for heart failure patients with intrinsic ventricular conduction disorders. In addition, proper placement of VfA pacing can provide optimal ventricular activation for such patients. In addition, for left ventricular (LV) resynchronization of heart failure patients with left bundle branch block (LBBB), it can be found that VfA pacing makes it easier to access the left ventricular endocardium without exposing a leadless device, or cause endocardial blood pooling. At the same time, in the example, this can help to engage portions of the conduction system to potentially correct LBBB and effectively resynchronize the patient.

[0166] Multiple external electrodes (such as Figure 13-15 The electrical activity can be monitored by a plurality of electrodes during VfA pacing therapy or in the absence of VfA pacing therapy. The monitored electrical activity can be used to evaluate VfA pacing therapy for a patient. The electrical activity monitored using the described ECG strip can be used to evaluate at least one pacing setting for VfA pacing therapy on the heart. As an example, the pacing setting can be any one parameter or a combination of parameters, including but not limited to electrode positioning, pacing polarity, pacing output, pacing pulse width, timing of VfA pacing relative to the atrium (A), pacing rate, etc. In addition, as an example, the position of the leadless device or pacing lead can include a position in the left ventricle, which enters the high posterior base and / or septum (HPBS) region of the left ventricular cavity through the right atrium or is in close proximity to it. In addition, pacing in or in close proximity to the HPBS region can be selective (e.g., involving stimulation of a specific region of only the HPBS), or non-selective (e.g., combined pacing at the position of the HPBS and other atrial and / or ventricular septal regions).

[0167] In addition, the monitored electrical activity can be used to construct a surface isochronal map of ventricular activation during VfA pacing therapy or in the absence of VfA pacing therapy. The monitored electrical activity and / or ventricular activation map can be used to generate electrical heterogeneity information (EHI). The electrical heterogeneity information can include a measure of determining electrical heterogeneity. The measure of electrical heterogeneity can include a measure of the standard deviation of activation times ((SDAT)) of the electrodes on the left side of the patient's torso and / or a measure of the average left ventricular activation time (LVAT) of the electrodes on the left side of the patient's torso. The measure of LVAT can be determined based on electrodes on both the anterior and posterior surfaces that are closer to the left ventricle. The measure of electrical heterogeneity information can include a measure of the average right ventricular activation time (RVAT) of the electrodes on the right side of the patient's torso. The measure of RVAT can be determined based on electrodes on both the anterior and posterior surfaces that are closer to the right ventricle. The measure of electrical heterogeneity may include a measure of the mean total activation time (mTAT) obtained from multiple electrode signals on both sides of the patient's torso, or it may include other measures (e.g., standard deviation, interquartile range, difference between the latest activation time and the earliest activation time) that reflect the range or dispersion of activation times on multiple electrodes located on the right side of the patient's torso or the left side of the patient's torso, or a combination of both the right and left sides of the patient's torso. The measure of electrical heterogeneity information may include a measure of the anterior septal activation time (ASAT) of electrodes on the torso that are in close proximity to the anterior septal portion of the heart.

[0168] Electrical heterogeneity information (EHI) may be generated during delivery of VfA pacing therapy with one or more VfA pacing settings. Electrical heterogeneity information may be generated using a measure of electrical heterogeneity. As an example, the measure of electrical heterogeneity may include one or more of SDAT, LVAT, RVAT, mTAT, and ASAT. In at least one embodiment, only ASAT may be determined and further used, and / or the weight of ASAT may be greater than other values.

[0169] One or more pacing settings associated with VfA pacing therapy can be evaluated. The pacing settings can include multiple pacing parameters. If the patient's cardiac condition improves, if the VfA pacing therapy effectively captures the desired portion of the left ventricle (e.g., the high posterior basal and / or septal regions), and / or if the measure of electrical heterogeneity improves by a certain threshold compared to the baseline rhythm or therapy, then the multiple pacing parameters can be optimal. In at least one embodiment, determining whether the pacing settings are optimal can be based on at least one measure of electrical heterogeneity generated from electrical activity during VfA pacing (and, in some embodiments, during natural conduction or in the absence of VfA pacing). The at least one measure can include one or more of SDAT, LVAT, RVAT, mTAT, and ASAT.

[0170] In addition, if the measure of electrical heterogeneity is greater than or less than a particular threshold, and / or if the location of the pacing therapy used to excite the left ventricle induces a particular stimulation pattern of muscle fibers in the heart, then the plurality of pacing parameters may be optimal. In addition, if the measure of electrical heterogeneity indicates correction of left bundle branch block (LBBB), and / or if the measure of electrical heterogeneity indicates full engagement of the Purkinje system, etc., then the plurality of pacing parameters may be optimal. As an example, a measure of electrical heterogeneity of ASAT less than or equal to a threshold (e.g., a threshold of 30 milliseconds) and LVAT less than or equal to a threshold (e.g., a threshold of 30 milliseconds) may indicate correction of LBBB, and thus the pacing settings may be optimal. As an example, a measure of electrical heterogeneity of RVAT less than or equal to a threshold (e.g., a threshold of 30 ms), an ASAT less than or equal to a threshold (e.g., a threshold of 30 ms), and a measure of electrical heterogeneity of LVAT less than or equal to a threshold (e.g., a threshold of 30 ms) may indicate full engagement of the Purkinje system, and thus the pacing settings may be optimal.

[0171] Pacing settings may be determined to be optimal in response to VfA pacing therapy using pacing settings that are acceptable, beneficial, indicate that the patient's native cardiac conduction system has been fully engaged, indicate correction of a ventricular conduction disorder (e.g., left bundle branch block), etc. Pacing settings may include one or more of: pacing electrode positioning (including one or more of depth, angle, number of turns of a screw-based fixation mechanism, etc.), voltage, pulse width, intensity, pacing polarity, pacing vector, pacing waveform, pacing timing delivered relative to intrinsic or paced atrial events or relative to intrinsic His bundle potentials, and / or pacing position, etc. Pacing vectors may include any two or more pacing electrodes, such as a tip electrode for delivering VfA pacing therapy to a can electrode, a tip electrode for delivering to a ring electrode, etc. A pacing position may refer to the position of any of one or more pacing electrodes positioned using a lead, a leadless device, and / or any device or apparatus configured to deliver VfA.

[0172] The pacing settings for VfA pacing therapy may be adjusted. In at least one embodiment, the pacing settings may be adjusted in response to a pacing setting that is not optimal. In at least one embodiment, the pacing settings may be adjusted in response to a pacing setting that is within an optimal range, but to determine whether the pacing settings may be positioned within the optimal range that is more beneficial, more useful, more practical, etc. for VfA pacing therapy. The pacing settings may be adjusted to find an optimal amount of electrical heterogeneity.

[0173] In one or more embodiments, a determination as to whether a pacing setting is optimal can be made based on a particular measure of electrical heterogeneity using an ECG strip. In at least one instance, the pacing setting can be adjusted at intervals associated with changes in the measure of electrical heterogeneity until the measure of electrical heterogeneity is equal to or close to the particular measure value. For example, adjustments to the pacing setting can cause the measure of electrical heterogeneity to approach a particular threshold measure of electrical heterogeneity, and as the measure approaches the particular threshold, the rate at which the pacing setting is adjusted can be slowed. In other words, when the measure of electrical heterogeneity is farther from the particular threshold measure, the pacing setting can be adjusted more quickly; and when the measure of electrical heterogeneity is close to the particular threshold measure, the pacing setting can be adjusted more slowly until the measure of electrical heterogeneity is at the particular threshold measure.

[0174] Various techniques for monitoring electrical activity from patient tissue using an electrode device having multiple external electrodes that can be used with the devices, systems, and methods described herein are disclosed in U.S. patent application serial number 15 / 934,517, entitled “Evaluation of Ventricle from Atrium Pacing Therapy,” filed on March 23, 2018, which is incorporated herein by reference in its entirety.

[0175] Positioning an implant site adjacent to or within the Koch's triangle area can be facilitated using various delivery systems and techniques disclosed herein. Various delivery systems and techniques can be used to deliver a pacing lead comprising a tissue-piercing electrode to an implant site adjacent to or within the Koch's triangle area. Specifically, some delivery systems and techniques can be used to deliver a pacing lead to a target implantation zone in the coronary sinus adjacent to the Koch's triangle area (e.g., near the coronary sinus ostium).

[0176] In some embodiments, the pacing leads of the present disclosure delivered to the implantation site may have a Figure 1-4 The pacing lead may include an elongated body defining a lumen extending from a proximal portion to a distal portion.

[0177] A left ventricular (LV) electrode can be coupled to the elongated body, the LV electrode being implantable from tissue adjacent to or within a Koch's triangle region of the right atrium (RA) through the right atrial endocardium and the central fiber body. The LV electrode can be configured to deliver cardiac therapy to the left ventricle or sense electrical activity of the left ventricle in a basal and / or septal region of the left ventricular myocardium of the patient's heart. The LV electrode can be configured to pierce tissue in an implantation site adjacent to or within a Koch's triangle region of the right atrium of the patient's heart to secure a pacing lead to the implantation site.

[0178] A right atrial (RA) electrode may also be coupled to an elongated body of the pacing lead that is proximal to the LV electrode and positionable within the RA. The RA electrode may be configured to deliver cardiac therapy to the right atrium of the patient's heart or sense electrical activity in the right atrium of the patient's heart.

[0179] Figure 16-25 Various configurations of pacing lead delivery system 500 are shown. Fig.16 A pacing lead delivery system 500 is shown that can be used to deliver a pacing lead to an implantation site adjacent to or within the Koch's triangle region. As shown, the delivery system 500 can include a sheath 502 extending from a proximal portion 504 (e.g., a proximal portion) to a distal portion 506 (e.g., a distal portion). The sheath 502 can include an elongated body that defines a lumen extending between the proximal portion 504 and the distal portion 506. The lumen of the sheath 502 can be configured to receive a guidewire. The lumen can be configured to receive a guidewire of one or more sizes (e.g., one or more diameters).

[0180] The sheath 502 of the delivery system 500 can be deflectable, have a fixed bend, or any combination of these. The deflectable sheath can be formed of any flexible or semi-rigid material (e.g., biocompatible) suitable for use during implantation. The fixed bend sheath can be formed of any rigid or semi-rigid material (e.g., biocompatible) suitable for use during implantation, such that one or more bend segments can be described as being substantially fixed or unchanging.

[0181] The sheath 502 may define or include one, two, three or more curved segments. In some embodiments, the sheath 502 has two or more bends or curved segments. In the illustrated embodiment, the sheath 502 of the delivery system 500 has a first curved segment 532 and a second curved segment 534. The first curved segment 532 may be used to reach the coronary sinus ostium or Koch's triangle region from the outside of the patient's heart. The second curved segment 534 may be used to point or orient the distal portion 506 of the sheath 502 toward the membrane septum adjacent to the LV (e.g., the septal wall). For example, the second curved segment 534 may be used to point the distal end of the sheath 502 toward the Koch's triangle region or the region inside the coronary sinus just near the coronary sinus ostium (e.g., adjacent to the Koch's triangle region). In some embodiments, the first curved segment 532 may have a fixed bend, and the second curved segment 534 may have a fixed bend, and the second curved segment may be telescopic relative to the first curved segment.

[0182] The curved segments can be deflectable, fixed, or a combination of both. For example, the first curved segment 532 can have a fixed bend, and the second curved segment 534 can be deflectable. In some embodiments, the deflectable curved segment can be configured to telescope. For example, the first curved segment 532 (e.g., an outer sheath or catheter) can be a separate piece from the second curved segment 534 (e.g., an inner sheath or catheter), and the second curved segment can be configured to telescope or adjust within the lumen of the first curved segment 532. In some embodiments, the second curved segment 534 can be configured to be adjustable by rotating, for example, up to 360 degrees relative to the first curved segment 532.

[0183] The curved segments can have the same or different curvatures. For example, in some embodiments, the first curved segment 532 can define a first radius of curvature and the second curved segment 534 can define a second radius of curvature that is less than the first radius of curvature. In some embodiments, the first curved segment 532 can be aligned with a first plane, and the second curved segment 534 can be aligned with a second plane having an orientation different from the first plane. For example, the first plane can be orthogonal to the second plane. In some embodiments, the first curved segment 532 can be adjustable (e.g., rotatable or retractable) relative to the second curved segment 534. Typically, the curvature of the sheath 502 can be defined based on the target implant site.

[0184] Various other components of the pacing lead delivery system 500 may be the same or similar to aspects described in U.S. Patent No. 6,132,456, issued October 17, 2000, entitled "Arrangement for Implanting Endomyocardial Leads," which is incorporated herein by reference in its entirety.

[0185] Fig.17 A close-up view of the distal portion 506 of the sheath 502 and the second curved portion segment 534 of the sheath is shown. As shown, the needle-tipped dilator 508 extends or projects distally from the distal portion 506 of the sheath 502. The needle-tipped dilator 508 can extend at least partially through the lumen of the sheath 502. The needle-tipped dilator 508 can be configured to form an opening in tissue at a potential implantation site. In some embodiments, the needle-tipped dilator 508 or a portion of the needle-tipped dilator 508 can be conductive (e.g., active). The needle-tipped dilator 508 can be used to engage tissue at a potential implantation site, and electrical stimulation can be monitored or delivered to the potential implantation site, which can facilitate determining whether the potential implantation site is acceptable.

[0186] Fig.18A -C shows various configurations near the distal portion 506 of the sheath 502. Fig.18A A needle-tipped dilator 508 is shown extending distally out of the sheath 502. The needle-tipped dilator 508 may be configured to be received within the lumen of the sheath 502. A guidewire 510 may also be received within the lumen of the sheath 502 and optionally within the lumen of the needle-tipped dilator 508.

[0187] The needle tip dilator 508 can include a needle portion 512 and a dilator portion 514. In some embodiments, the needle tip dilator 508 can be formed from a single integral piece. In other embodiments, the needle portion 512 and the dilator portion 514 can be separately formed pieces that cooperatively act as a needle tip dilator. For example, the needle portion 512 can be received within the lumen of the dilator portion 514 and can be separated or freely translated in the longitudinal direction (e.g., aligned with the length of the sheath when received). In some embodiments, the needle portion 512, the dilator portion 514, or both can be conductive (e.g., active) or insulated (e.g., passive).

[0188] The needle-tipped dilator 508 may define or include a lumen extending from a proximal portion to a distal portion of the needle-tipped dilator. In some embodiments, the lumen of the needle-tipped dilator 508 may be configured to advance over a guidewire 510 or a guidewire 511. As shown, the diameter of the guidewire 511 may be greater than the diameter of the guidewire 510.

[0189] Fig.18B-C shows a pacing lead 516 extending distally out of the sheath 502. The pacing lead 516 can be freely translated in the longitudinal direction relative to the sheath 502, the guidewire 510, or both. At least the pacing lead 516 can be rotatable relative to the sheath 502, the guidewire 510, or both. In general, the pacing lead 516 can be made of Fig.18B The guide wire 510 shown in Fig.18C The lumen of the sheath 502 shown in , or both, are guided to the implantation site.

[0190] The pacing lead 516 can include an elongated body extending from a proximal portion to a distal portion. As shown, the pacing lead 516 can also include a fixation element 518 coupled to the distal portion of the pacing lead. The fixation element 518 can be configured to attach to an implantation site in the right atrial endocardium adjacent to or within the Koch's triangle region in the right atrium of the patient's heart. Any suitable fixation structure can be used for the fixation element 518. In the illustrated embodiment, the fixation element 518 is a spiral attachment element.

[0191] In some embodiments, fixation element 518 may also serve as a LV electrode (e.g., a tissue-piercing electrode having a spiral shape). In other embodiments, fixation element 518 may be formed separately from the LV electrode (e.g., if the LV electrode is a dart-shaped electrode). For example, fixation element 518 may be placed proximal to the LV electrode along pacing lead 516.

[0192] Although not shown here, the pacing lead 516 may include an atrial electrode, such as a right atrium (RA) electrode, a left atrium (LA) electrode, or both. The RA electrode may be positioned adjacent to the fixation element 518, the LV electrode, or both, or at a distance proximal to the fixation element, the LV electrode, or both. The RA electrode may be positioned on the pacing lead 516 so that the RA electrode is positioned adjacent to the RA when the LV electrode is implanted. The LA electrode may be positioned adjacent to the fixation element 518, the LV electrode, or both, or at a distance proximal to the fixation element, the LV electrode, or both. The LA electrode may be positioned on the pacing lead 516 so that the LA electrode is positioned adjacent to the proximal portion of the coronary sinus when the LV electrode is implanted. The RA electrode, the LA electrode, or both may be used to sense or pace the corresponding portion of the atrium of the patient's heart. In some embodiments, the RA electrode, the LA electrode, or both may be used to provide timing and coordination information about atrial activity.

[0193] like Fig.18BAs shown in , the pacing lead 516 can include a lumen extending through the elongated body. The lumen of the pacing lead 516 can be configured to receive the guidewire 510. In some embodiments, the lumen of the pacing lead 516 may not accommodate the size or diameter of the guidewire 511, which may affect the selected implantation method.

[0194] Fig.19 A distal portion 506 of the sheath 502 is shown having a guidewire 511 received within and extending out of a lumen of a needle-tipped dilator 508. As shown, the needle-tipped dilator 508 is received within and extends out of the lumen of the sheath 502.

[0195] Fig. 20 5 is an illustration of a distal portion 506 of a sheath 502 having a guidewire 510 received within and extending out of a lumen of the sheath 502. As shown, a guidewire 511 ( Fig.19 ) can have a diameter greater than the diameter of the guide wire 510.

[0196] Figure 21-25 The use of a guide wire 510 (see Fig. 20 ) configurations. Fig.21 A distal portion 506 of the sheath 502 is shown containing a needle-tipped dilator 508 and a guidewire 510 in a position that may be used for advancement toward a potential implantation site.

[0197] Fig. 22 A distal portion 506 of the sheath 502 is shown, which has a guidewire 510 that is retracted or pulled back into the lumen of the needle-tipped dilator 508. This positioning can be used to test potential implant sites using the needle portion 512. In some embodiments, the needle portion 512 can be inserted into the tissue to test the response to the electrical pulse and / or sense electrical activity at one or more depths within the tissue. If the implant site is acceptable, the dilator portion 514, the guidewire 510, or both can be further pushed into the tissue to create a hole in the tissue that can be used to accommodate a pacing lead. For example, when the guidewire is formed to be semi-rigid or rigid (e.g., hard) so that the guidewire can be pushed into the tissue without the need for the needle-tipped dilator 508 to be pushed into the tissue, the guidewire 510 can be used. In some embodiments, the guidewire 510 can be used instead of the needle-tipped dilator 508 for one or more functions described herein.

[0198] Fig.23A proximal portion 504 of the sheath 502 is shown, containing a guidewire 510 and a needle-tipped dilator 508. As illustrated, the needle-tipped dilator 508 may be removed from the sheath 502 and guidewire 510 in a proximal direction, for example, after determining that a potential implantation site is acceptable.

[0199] Fig.24 The proximal portion 504 of the sheath 502 is shown, which contains the guidewire 510 and the pacing lead 516. As shown, the needle tip dilator 508 ( Fig.23 ) may be exchanged with pacing lead 516. Guidewire 510 may be described as an exchange lead or exchange length lead that may have sufficient length to facilitate such an exchange.

[0200] The guidewire 510 may remain at least partially disposed in the lumen of the sheath 502. In some embodiments, the distal end of the guidewire 510 may be positioned in the hole in the implantation site formed by the needle-tipped dilator 508. The pacing lead 516 may be advanced distally over the guidewire 510 toward the implantation site.

[0201] In another embodiment (not shown), the guidewire 510 can be removed in a proximal direction from the sheath 502 and the needle-tipped dilator 508. The distal portion 506 of the sheath 502 can be positioned in the hole formed by the needle-tipped dilator 508 in the implantation site. The pacing lead 516 can be advanced distally through the lumen of the sheath 502 to the implantation site.

[0202] Fig.25 A distal portion 506 of a sheath 502 is shown with a pacing lead 516 extending distally out of the lumen of the sheath and a guidewire 510 extending distally out of the lumen of the pacing lead. This positioning can be used to advance the pacing lead 516 to an implantation site.

[0203] Once the pacing lead 516 reaches the implantation site, the pacing lead (e.g., the LV electrode of the pacing lead) can be used to test the tissue at the site. Testing the implantation site can include delivering electrical pulses (e.g., stimulation), sensing or detecting electrical activity (e.g., intrinsic activity or response to electrical pulses), or both. If the implantation site is acceptable, the pacing lead 516 can be fixed to the implantation site, and the guidewire 510 and the sheath 502 can be retracted.

[0204] Various methods can be used with Figure 16-25 The pacing lead delivery system 500 described in is used together with the pacing lead delivery system 500 described in to implant a pacing lead adjacent to or in the Koch triangle area. Figure 26-34 Various techniques are shown that can be used to perform the delivery.

[0205] Figure 26-27 The pacing lead delivery system 500 is shown advanced to an implantation site. Fig.26 A right anterior oblique section view of a patient's heart 8 is shown. Fig. 27 A top cross-sectional view is shown. In some embodiments, the delivery system 500 can be configured to position the LV electrode of the pacing lead less than or equal to 3 centimeters (cm), 2 cm, 1 cm, or even 0.5 cm from the right atrium into the coronary sinus. The first curved segment 532 can be used to position the delivery system 500 near the Koch's triangle area, and the second curved segment 534 can be used to orient the distal portion to an implantation site adjacent to or within the Koch's triangle area. As shown, the implantation site is adjacent to the Koch's triangle area (e.g., in the coronary sinus 3 near the coronary sinus ostium).

[0206] Fig. 27 The pacing lead delivery system 500 is shown relative to the aortic valve 540, the pulmonary valve 542, the right coronary artery 544, the tricuspid valve 6, the mitral valve 546, the coronary sinus 3, and the great coronary vein 548.

[0207] Fig.28 A target implantation zone 550 is shown in the coronary sinus near the coronary sinus ostium adjacent to the Koch's triangle region. The target implantation zone 550 is beneath the mitral valve 546 within the coronary sinus on the LV wall. The angle of implantation into the target implantation zone 550 can be selected to deliver the LV electrode of the pacing lead to the basal region, septal region, or basal-septal region of the left ventricular myocardium.

[0208] Fig.29 The present invention shows a pacing lead delivery system (such as pacing lead delivery system 500 ( Figure 16-28 )) method 900. Method 900 may include locating a potential implantation site 902. In some embodiments, the potential implantation site may be located adjacent to or within a region of Koch's triangle in the right atrium of the patient's heart. Method 900 may include advancing a pacing lead to the potential implantation site 904. The pacing lead may include an elongated body extending from a proximal portion to a distal portion and a fixation element coupled to the distal portion and attachable to a right atrial endocardium adjacent to or within a region of Koch's triangle in the right atrium of the patient's heart, for example to deliver cardiac therapy to the left ventricle or sense electrical activity of the left ventricle in a basal region, a septal region, or a basal-septal region of the left ventricular myocardium of the patient's heart.

[0209] Method 900 may include positioning a pacing lead at a potential implantation site 906. In some embodiments, implanting a pacing lead may include implanting a left ventricular electrode coupled to the distal portion of the pacing lead from tissue adjacent to or within the Koch's triangle region of the right atrium through the right atrial endocardium and optionally the central fibrous body to deliver cardiac therapy to the left ventricle or sense the electrical activity of the left ventricle in the basal and / or septal regions of the left ventricular myocardium of the heart of the patient. For example, when implanted through the coronary sinus, the right fibrous trigone and the membranous septum may not be penetrated by the left ventricular electrode. In some embodiments, the left ventricular electrode may be described as being implanted from tissue adjacent to or within the Koch's triangle region of the right atrium through the right atrial endocardium and the central fibrous body. In some embodiments, implanting a pacing lead may include positioning the right atrial electrode of the pacing lead proximal to the fixation element to deliver cardiac therapy to the right atrium of the heart of the patient or sense the electrical activity of the right atrium of the heart of the patient.

[0210] Fig.30 An example of a method for locating a potential implantation site 902 is shown. The method 902 may include inserting a guidewire into a lumen of a sheath 912. The method 902 may include advancing the guidewire or sheath to an implantation site 914, such as into the coronary sinus of the patient's heart to an area beneath the mitral valve near the ostium of the coronary sinus.

[0211] Method 902 can include advancing a needle-tipped dilator 916, for example, over a guidewire and through a lumen of a sheath to the coronary sinus. Method 902 can also include engaging tissue in a potential implantation site 918, for example, adjacent to or within a Koch's triangle region in a right atrium of a heart of a patient, with the needle-tipped dilator.

[0212] Method 902 may include testing a potential implant site adjacent to or within a Koch's triangle in the right atrium of the patient's heart using a needle tip dilator 920. Method 902 may also include determining whether the potential implant site is acceptable 922, for example, based on the testing using the needle tip dilator.

[0213] Fig.31 Another example of a method for locating a potential implantation site 902 is shown. The method 902 can include determining whether the site is acceptable 922. In response to the site being unacceptable, the method 902 can include withdrawing a needle-tipped dilator 926, for example, from tissue in the potential implantation site. The method 902 can also include locating a new potential implantation site 928, for example, adjacent to or within the Koch's triangle region in the right atrium of the patient's heart.

[0214] In response to the site being acceptable, method 902 can include using a needle-tipped dilator, for example, to form an opening in tissue 930 in the potential implantation site. Method 902 can also include preparing an implantation site for a pacing lead, for example, based on the size of the guidewire. For example, an implantation method 940 ( Fig.32 ) can be used with a guidewire having a large diameter (e.g., 0.035 inches), while another implantation method 950 ( Fig.33 ) can be used for guidewires with smaller diameters (e.g., 0.014 inches).

[0215] Fig.32 An example of a method for preparing an implantation site 940 is shown. The method 940 may include advancing a guide wire to a potential implantation site 942. The method 940 may also include advancing a sheath over a guide wire 944, for example, into an opening formed by a needle-tipped dilator in tissue in the potential implantation site. In some embodiments, the sheath may be advanced as far as possible into the opening.

[0216] The method 940 can include, for example, withdrawing the needle-tipped dilator 946 through the lumen of the sheath. The guidewire can also be withdrawn through the lumen of the sheath. The method 940 can also include advancing the pacing lead to the potential implantation site 948, for example, while the pacing lead is at least partially disposed in the lumen of the sheath so that the sheath guides the pacing lead to the potential implantation site.

[0217] Fig.33 Another example of a method for preparing an implantation site 950 is shown. The method 950 can include advancing a guidewire into an opening formed by a needle-tipped dilator in tissue, for example, in an implantation site 952. The method 950 can include withdrawing the needle-tipped dilator 954, for example, over the guidewire so that the pacing lead is guided by the guidewire to the implantation site.

[0218] The method 950 can include exchanging the needle tip dilator with the pacing lead 956. The method 950 can also include advancing the pacing lead 958 to the implantation site, for example, over a guidewire.

[0219] Fig.34 Another example of a method for preparing an implant site 960 is shown, which may follow method 940 or method 950. Method 960 may include testing the implant site using a pacing lead 962, for example, after the pacing lead has been guided to the implant site by a sheath or guidewire. Method 960 may also include determining whether a potential implant site is acceptable 964, for example, based on the testing performed using the pacing lead.

[0220] Based on the determination, in response to the implant site being unacceptable 966, method 960 can include locating a new potential implant site 968. Method 960 can return to testing with a needle tip dilator or pacing lead.

[0221] In response to the implantation site being acceptable 966, the method 960 can include securing the pacing lead in the implantation site 970. After the pacing lead is implanted and deemed acceptable, the sheath or guidewire can be removed and only the pacing lead can remain at the implantation site. Specifically, the LV electrode can be positioned in the basal region, septal region, or basal-septal region of the left ventricular myocardium via an area adjacent to or within the Koch's triangle.

[0222] In some embodiments, an imageable material (e.g., a radiopaque material) can be used to form part or all of some components of the delivery system to guide the distal portion of the delivery system to an implantation site adjacent to or within the Koch's triangle area to position the LV electrode in the basal region, septal region, or basal-septal region of the left ventricular myocardium. For example, the distal portion of the sheath can be at least partially formed of an imageable material. Various examples of imageable materials and imageable components (e.g., imageable members) are described in U.S. patent application serial number 16 / 227,774, entitled "Implantable Medical Device Delivery for Cardiac Therapy," filed on December 20, 2018, which is incorporated herein by reference in its entirety.

[0223] Illustrative Embodiments

[0224] Although the present disclosure is not so limited, an understanding of various aspects of the present disclosure will be gained through a discussion of the illustrative embodiments provided below. Various modifications to the illustrative embodiments, as well as additional embodiments of the present disclosure, will become apparent herein.

[0225] In illustrative embodiment A1, a method for delivering a pacing lead includes positioning a potential implantation site adjacent to or within a Koch's triangle area in the right atrium of a patient's heart; advancing a pacing lead to the potential implantation site, the pacing lead comprising an elongated body and a fixation element, the elongated body extending from a proximal portion to a distal portion, the fixation element coupled to the distal portion and attachable to the right atrial endocardium adjacent to or within the Koch's triangle area in the right atrium of the patient's heart; and implanting the pacing lead at the potential implantation site to deliver cardiac therapy to the left ventricle and sense electrical activity of the left ventricle in a basal region, a septal region, or a basal-septal region of the left ventricular myocardium of the patient's heart.

[0226] In illustrative embodiment A2, a method includes a method according to any A embodiment, the method including implanting a left ventricular electrode connected to the distal portion of the pacing lead from tissue adjacent to or within the Koch triangle area of ​​the right atrium through the right atrial endocardium and optionally the central fiber body to deliver cardiac therapy to the left ventricle in the basal region, the septal region, or the basal-septal region of the left ventricular myocardium of the patient's heart and sense the electrical activity of the left ventricle.

[0227] In illustrative embodiment A3, a method includes the method according to any A embodiment, the method further including positioning an atrial electrode of the pacing lead adjacent to or proximal to the fixation element to deliver cardiac therapy to the atrium of the patient's heart or to sense electrical activity in the atrium of the patient's heart.

[0228] In illustrative embodiment A4, a method includes the method according to any A embodiment, wherein locating the potential implantation site includes: optionally, inserting a guidewire into a lumen of a sheath; advancing the guidewire and the sheath into the coronary sinus of the patient's heart; advancing a needle-tipped dilator over the guidewire and through the lumen of the sheath to the coronary sinus; engaging tissue in the potential implantation site adjacent to or within the Koch's triangle area in the right atrium of the patient's heart with the needle-tipped dilator; testing the potential implantation site adjacent to or within the Koch's triangle area in the right atrium of the patient's heart using the needle-tipped dilator; and determining whether the potential implantation site is acceptable based on the testing performed using the needle-tipped dilator.

[0229] In illustrative embodiment A5, a method includes the method according to embodiment A4, the method further comprising: withdrawing the needle-tipped dilator from tissue in the potential implantation site in response to determining that the potential implantation site is unacceptable; and optionally, positioning a new potential implantation site adjacent to or within the Koch's triangle area in the right atrium of the patient's heart.

[0230] In illustrative embodiment A6, a method includes the method of embodiment A4 or A5, further comprising forming an opening in tissue in the potential implantation site using the needle-tipped dilator in response to determining that the potential implantation site is acceptable.

[0231] In illustrative embodiment A7, a method includes the method according to any A embodiment, the method further comprising preparing the potential implantation site for the pacing lead based on the size of the guidewire.

[0232] In illustrative embodiment A8, a method includes the method according to embodiment A7, wherein preparing the potential implantation site for the pacing lead includes: advancing the guide wire to the potential implantation site; advancing a sheath over the guide wire and into an opening formed by a needle-tipped dilator in tissue in the potential implantation site; and withdrawing the needle-tipped dilator and the guide wire through the lumen of the sheath, wherein the pacing lead is advanced to the potential implantation site when the pacing lead is able to be at least partially positioned in the lumen of the sheath.

[0233] In illustrative embodiment A9, a method includes the method according to embodiment A7, wherein preparing the potential implantation site for the pacing lead includes: advancing the guide wire into an opening formed by a needle-tipped dilator in tissue in the potential implantation site; retracting the needle-tipped dilator over the guide wire; and exchanging the needle-tipped dilator with the pacing lead, wherein the pacing lead is advanced over the guide wire to the potential implantation site.

[0234] In illustrative embodiment A10, a method includes the method of any of embodiments A4 to A9, wherein the needle tip dilator includes a dilator portion and a needle portion detachable from the dilator portion.

[0235] In illustrative embodiment A11, a method includes the method according to any A embodiment, the method further including: testing the potential implantation site using the pacing lead; determining whether the potential implantation site is acceptable based on the test performed using the pacing lead; and fixing the pacing lead in the potential implantation site in response to determining that the potential implantation site is acceptable based on the test performed using the pacing lead.

[0236] In illustrative embodiment B1, a pacing lead delivery system includes a sheath comprising an elongated body defining a lumen extending between a proximal portion and a distal portion; a guidewire capable of being at least partially disposed in the lumen of the sheath; a needle-tipped dilator configured to advance over the guidewire and engage tissue in a potential implantation site; and a pacing lead comprising an elongated body and a fixation element extending from the proximal portion to the distal portion, the fixation element being coupled to the distal portion and attachable to an implantation site in the right atrial endocardium adjacent to or within a Koch's triangle region in the right atrium of a patient's heart to deliver cardiac therapy to the left ventricle and sense electrical activity in the basal region, septal region, or basal-septal region of the left ventricular myocardium of the patient's heart.

[0237] In illustrative embodiment B2, a system includes the system of any B embodiment, wherein the elongated body defines a lumen extending between the proximal portion and the distal portion, the lumen being configured to receive the guidewire.

[0238] In illustrative embodiment B3, a system includes the system of any B embodiment, wherein the fixation element of the pacing lead includes a helical attachment element.

[0239] In illustrative embodiment B4, a system includes the system of embodiment B3, wherein the pacing lead is freely rotatable relative to the sheath, the guidewire, or both.

[0240] In illustrative embodiment B5, a system includes the system of any B embodiment, wherein the sheath includes a fixed bend configured to extend using the coronary sinus to the implantation site adjacent to or within the Koch's triangle area in the right atrium of the patient's heart.

[0241] In illustrative embodiment B6, a system includes the system of any B embodiment, wherein the sheath is deflectable and includes a first curved portion segment and a second curved portion segment distal to the first curved portion segment, the first curved portion segment and the second curved portion segment being configured to extend through the coronary sinus to the implantation site adjacent to or within the Koch's triangle area in the right atrium of the patient's heart.

[0242] In illustrative embodiment B7, a system includes the system of embodiment B6, wherein the first curved segment has a first radius of curvature, and the second curved segment has a second radius of curvature that is smaller than the first radius of curvature.

[0243] In illustrative embodiment B8, a system includes the system of embodiment B6 or B7, wherein the first curved portion segment is aligned with a first plane and the second curved portion segment is aligned with a second plane having a different orientation than the first plane.

[0244] In illustrative embodiment B9, a system includes the system of any of embodiments B6 to B8, wherein the first curved portion segment is adjustable relative to the second curved portion segment.

[0245] In illustrative embodiment B10, a system includes the system of any B embodiment, wherein the needle-tipped dilator or the guidewire is configured to form an opening in tissue in the potential implantation site.

[0246] In illustrative embodiment B11, a system includes the system of embodiment B10, wherein the sheath is configured to be inserted into the opening in tissue formed by the needle-tipped dilator to guide the pacing lead to the potential implantation site.

[0247] In illustrative embodiment B12, a system includes the system of embodiment B10, wherein the guidewire is configured to be inserted into the opening in tissue formed by the needle-tipped dilator to guide advancement of the pacing lead to the potential implantation site.

[0248] In illustrative embodiment C1, a pacing lead includes an elongated body defining a lumen extending from a proximal portion to a distal portion, the lumen being configured to receive a guide wire; and a left ventricular electrode connected to the elongated body, the left ventricular electrode being implantable through the right atrial endocardium from tissue adjacent to or within the Koch's triangle area of ​​the right atrium to deliver cardiac therapy to the left ventricle and sense electrical activity of the left ventricle in a basal region, a septal region, or a basal-septal region of the left ventricular myocardium of the patient's heart.

[0249] In illustrative embodiment C2, a pacing lead includes the pacing lead according to any C embodiment, further including an atrial electrode connected to the slender body, the atrial electrode being proximal to the left ventricular electrode and capable of being positioned within the atrium to deliver cardiac therapy to the atrium of the patient's heart or to sense electrical activity in the atrium of the patient's heart.

[0250] In illustrative embodiment C3, a pacing lead includes the pacing lead according to any C embodiment, wherein the left ventricular electrode is configured to pierce tissue in an implantation site adjacent to or within the Koch triangle area of ​​the right atrium of the patient's heart to secure the pacing lead to the left ventricular myocardium.

[0251] In illustrative embodiment C4, a pacing lead includes the pacing lead according to any C embodiment, wherein the left ventricular electrode includes a helical attachment element.

[0252] In illustrative embodiment D1, a pacing lead delivery system includes a sheath comprising an elongated body defining a lumen extending between a proximal portion and a distal portion; a guidewire that can be at least partially disposed in the lumen of the sheath and is configured to engage tissue in a potential implantation site; and a pacing lead comprising an elongated body and a fixation element, the elongated body extending from the proximal portion to the distal portion, the fixation element being coupled to the distal portion and attachable to an implantation site in the right atrial endocardium adjacent to or within a Koch's triangle region in the right atrium of a patient's heart, to reach the left ventricle in a basal region, a septal region, or a basal-septal region of the left ventricular myocardium of the patient's heart and sense electrical activity of the left ventricle.

[0253] In illustrative embodiment D2, a system includes the system of any D embodiment, wherein the elongated body defines a lumen extending between the proximal portion and the distal portion, the lumen being configured to receive the guidewire.

[0254] Thus, various embodiments of delivery systems and methods for left ventricular pacing are disclosed. Although reference is made herein to a collection of drawings that form part of the present disclosure, at least one of ordinary skill in the art will understand that various adaptations and modifications of the embodiments described herein are within the scope of or do not depart from the scope of the present disclosure. For example, various aspects of the embodiments described herein may be combined with one another in a variety of ways. Therefore, it should be understood that, within the scope of the appended claims, the claimed invention may be practiced in a manner other than as expressly described herein.

[0255] It should be understood that the various aspects disclosed herein can be combined in different combinations other than those specifically presented in the specification and drawings. It should also be understood that, according to examples, the actions or events of any process or method described herein can be performed in different orders, can be added, merged, or completely excluded (for example, all described actions and events may not be necessary for performing the technology). In addition, for the purpose of clarity, although certain aspects of the present disclosure are described as being performed by a single module or unit, it should be understood that the technology of the present disclosure can be performed by a combination of units or modules associated with, for example, a medical device.

[0256] In one or more examples, the described techniques may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored as one or more instructions or codes on a computer-readable medium and executed by a hardware-based processing unit. A computer-readable medium may include a non-transitory computer-readable medium, which corresponds to a tangible medium, such as a data storage medium (e.g., RAM, ROM, EEPROM, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and can be accessed by a computer).

[0257] Instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general-purpose microprocessors, application-specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuit systems. Therefore, the term "processor" as used herein may refer to any of the aforementioned structures or any other physical structure suitable for implementing the described technology. Moreover, the technology may be fully implemented in one or more circuits or logic elements. It should be understood that each block of the block diagram and the combination of these blocks may be implemented by a device for performing the functions shown.

[0258] All references and publications cited herein are expressly incorporated by reference in their entirety for all purposes unless in any respect directly contradicted by this disclosure.

[0259] Unless otherwise specified, all scientific and technical terms used herein have the meanings commonly used in the art. The definitions provided herein are to facilitate understanding of certain terms frequently used herein and are not meant to limit the scope of the present disclosure.

[0260] Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims may be understood as being modified by the terms “exactly” or “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and the appended claims are approximations that may vary depending on the desired properties sought to be obtained by one skilled in the art utilizing the teachings disclosed herein or, for example, within the typical range of experimental error.

[0261] Numerical ranges recited by endpoints include all numbers subsumed within the range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5) and any range within the range. As used herein, the term "at most" or "not greater than" a number (e.g., at most 50) includes the number (e.g., 50), and the term "not less than" a number (e.g., not less than 5) includes the number (e.g., 5).

[0262] The terms "coupled" or "connected" refer to elements being directly connected to each other (directly in contact with each other) or indirectly connected (having one or more elements between the two elements and connecting them). Both terms can be modified by "operatively" and "operably", which are used interchangeably to describe that the connection or connection is configured to allow the components to interact to perform at least some function.

[0263] Terms related to orientation, such as "above" and "below" are used to describe the relative positioning of components and are not meant to limit the orientation of the contemplated embodiments. For example, an embodiment described as having a "top" and a "bottom" also includes embodiments thereof rotated in all directions unless the context clearly indicates otherwise.

[0264] Reference to "one embodiment," "an embodiment," "certain embodiments," or "some embodiments" or the like means that a particular feature, configuration, composition, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Thus, the appearances of these phrases in various places do not necessarily refer to the same embodiment of the present disclosure. Furthermore, in one or more embodiments, the particular features, configurations, compositions, or characteristics may be combined in any suitable manner.

[0265] The words "preferred" and "preferably" refer to embodiments of the present disclosure that may provide certain benefits in certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. In addition, the description of one or more preferred embodiments does not mean that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the present disclosure.

[0266] As used in this specification and the appended claims, the singular forms "a," "an," and "the" encompass embodiments having plural referents, unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally used in its sense to include "and / or," unless the content clearly dictates otherwise.

[0267] As used herein, "have", "having", "include", "including", "comprise", and the like are used in their open-ended sense and generally mean "including but not limited to". It will be understood that "consisting essentially of", "consisting of", and the like are encompassed by "comprising", and the like.

[0268] The term "and / or" means one or all of the listed elements or a combination of at least two of the listed elements.

[0269] The phrases "at least one," "including at least one," and "one or more" following a list refer to any one of the items in the list and any combination of two or more items in the list.

Claims

1. A pacing lead delivery system, comprising: a sheath comprising an elongated body defining a lumen extending between a proximal portion and a distal portion; a guidewire capable of being at least partially disposed within the lumen of the sheath; a needle-tipped dilator configured to be advanced over the guidewire and engage tissue in a potential implantation site; as well as A pacing lead comprising an elongated body extending from a proximal portion to a distal portion, the fixation element coupled to the distal portion and attachable to an implantation site in the right atrial endocardium adjacent to or within the Koch's triangle region in the right atrium of a patient's heart to deliver cardiac therapy to the left ventricle in a basal region, a septal region, or a basal-septal region of the left ventricular myocardium of the patient's heart and sense electrical activity of the left ventricle.

2. The pacing lead delivery system of claim 1, wherein the elongated body defines a lumen extending between the proximal portion and the distal portion, the lumen being configured to receive the guidewire.

3. A pacing lead delivery system according to claim 1 or 2, wherein the fixation element of the pacing lead comprises a spiral attachment element.

4. A pacing lead delivery system according to claim 3, wherein the pacing lead is capable of freely rotating relative to the sheath, the guide wire, or both.

5. A pacing lead delivery system according to any of the preceding claims, wherein the sheath includes a fixed bend configured to extend using the coronary sinus to the implantation site adjacent to or within the Koch's triangle area in the right atrium of the patient's heart.

6. A pacing lead delivery system according to any one of claims 1 to 4, wherein the sheath is deflectable and includes a first curved portion segment and a second curved portion segment distal to the first curved portion segment, the first curved portion segment and the second curved portion segment being configured to extend through the coronary sinus to the implantation site adjacent to or within the Koch's triangle area in the right atrium of the patient's heart.

7. The pacing lead delivery system of claim 6, wherein the first curved portion segment has a first radius of curvature, and the second curved portion segment has a second radius of curvature that is smaller than the first radius of curvature.

8. A pacing lead delivery system according to claim 6 or 7, wherein the first curved portion segment is aligned with a first plane and the second curved portion segment is aligned with a second plane having an orientation different from the first plane.

9. The pacing lead delivery system of any one of claims 6 to 8, wherein the first curved portion segment is adjustable relative to the second curved portion segment.

10. The pacing lead delivery system of any of the preceding claims, wherein the needle-tipped dilator or the guidewire is configured to form an opening in tissue in the potential implantation site.

11. The pacing lead delivery system of claim 10, wherein the sheath is configured to be inserted into the opening in tissue formed by the needle-tipped dilator to guide the pacing lead to the potential implantation site.

12. The pacing lead delivery system of claim 10, wherein the guidewire is configured to be inserted into the opening in tissue formed by the needle-tipped dilator to guide advancement of the pacing lead to the potential implantation site.

13. A pacing lead, comprising: an elongated body defining a lumen extending from a proximal portion to a distal portion, the lumen being configured to receive a guidewire; as well as A left ventricular electrode is connected to the slender body and can be implanted through the right atrial endocardium from tissue adjacent to or within the Koch's triangle area of ​​the right atrium to deliver cardiac therapy to the left ventricle and sense electrical activity of the left ventricle in the basal region, septal region, or basal-septal region of the left ventricular myocardium of the patient's heart.

14. The pacing lead of claim 13, further comprising an atrial electrode coupled to the elongated body, the atrial electrode being proximal to the left ventricular electrode and being positionable within the atrium to deliver cardiac therapy to the atrium of the patient's heart or to sense electrical activity in the atrium of the patient's heart.

15. The pacing lead of claim 13 or 14, wherein the left ventricular electrode is configured to pierce tissue in an implantation site adjacent to or within a Koch's triangle area of ​​the right atrium of the patient's heart to secure the pacing lead to the left ventricular myocardium.

16. The pacing lead of any one of claims 13 to 15, wherein the left ventricular electrode comprises a helical attachment element.

17. A pacing lead delivery system, comprising: a sheath comprising an elongated body defining a lumen extending between a proximal portion and a distal portion; a guidewire capable of being at least partially disposed within the lumen of the sheath and configured to engage tissue in a potential implantation site; as well as A pacing lead comprising an elongated body extending from a proximal portion to a distal portion, the fixation element being coupled to the distal portion and attachable to an implantation site in the right atrial endocardium adjacent to or within the Koch's triangle region in the right atrium of the patient's heart, to reach the left ventricle in the basal region, septal region, or basal-septal region of the left ventricular myocardium of the patient's heart and sense electrical activity of the left ventricle.

18. The pacing lead delivery system of claim 17, wherein the elongated body defines a lumen extending between the proximal portion and the distal portion, the lumen being configured to receive the guidewire.

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