Device for cardiac conduction system pacing

Abstract

The present disclosure relates generally to pacing of a patient's cardiac conduction system, and more particularly to providing adaptive cardiac conduction system pacing therapy and to determining selective or non-selective capture of the cardiac conduction system by the cardiac conduction system pacing therapy. The adaptive cardiac conduction system pacing therapy can adjust AV and VV delays based on various signals and metrics, and can switch between cardiac conduction system pacing therapy alone and cardiac conduction system pacing therapy in combination with traditional left ventricular pacing therapy.

Description

[0001] This disclosure relates generally to pacing of a patient’s cardiac conduction system, and more specifically to providing adaptive cardiac conduction system pacing therapy and to determining whether cardiac conduction system pacing therapy selectively or non-selectively captures the cardiac conduction system.

[0002] Implantable medical devices (IMDs), such as pacemakers or implantable cardioverter defibrillators, deliver therapeutic stimulation to a patient's heart, thereby improving the quality of life for millions of patients with heart disease. Conventional pacing techniques involve pacing one or more of the four chambers of the patient's heart (left atrium (LA) 33, right atrium (RA) 26, left ventricle (LV) 32, and right ventricle (RV) 28), all of which are shown in [the diagram / illustration]. Figure 1 In this context, a common, routine therapeutic pacing technique for treating slow heart rates known as bradycardia involves delivering an electrical pulse to the tissues of the patient's right ventricle. In response to the electrical pulse, both the right and left ventricles contract. However, because the pulse travels from the right ventricle through the left ventricle, the heartbeat process can be significantly delayed. The electrical pulse travels through muscle cells called myocytes. Myocyte-to-myocellular conduction can be very slow. This delayed electrical pulse can cause the left ventricle to become out of sync with the right ventricle.

[0003] Over time, the left ventricle can become significantly less efficient at pumping blood into the body. In some patients, heart failure may develop, making the heart too weak to pump blood effectively. Heart failure can be a frustrating diagnosis because, for example, 50% of patients with heart failure have a life expectancy of only 5 years. To avoid the potential development of heart failure, some doctors have considered alternative pacing methods involving the heart's conduction system. The heart's conduction system is like a "superhighway," which can be described as rapidly conducting electrical impulses, while pacing myocardial tissue conducts electrical impulses slowly, like "traveling on a dirt road."

[0004] The cardiac conduction system includes the sinoatrial node (SA node) 1, internodal tracts 2, 4, and 5 (i.e., anterior internodal tract 2, middle internodal tract 4, and posterior internodal tract 5), atrioventricular node (AV node) 3, His bundle 13 (also known as the atrioventricular bundle or His bundle), and right bundle branch 8b and left bundle branch 8a. Figure 1The aortic arch 6 and the Backmann bundle 7 are also shown. The SA node, located at the junction of the superior vena cava and the right atrium, is considered the heart's natural pacemaker because it continuously and repeatedly fires electrical impulses. These impulses travel through the muscle of the right atrium 26 to the left atrium 33 to induce synchronous atrial contractions. The impulses are also delivered via the internodal tract to the atrioventricular (AV) node 3, the only connection between the atria and ventricles. Conduction through the AV node tissue takes longer than through the atrial tissue, resulting in a delay between atrial contraction and the onset of ventricular contraction. The AV delay, the delay between atrial and ventricular contraction, allows the atria to empty blood into the ventricles. The valves between the atria and ventricles then close before ventricular contraction is induced by the branches of the His bundle 13. The His bundle 13 is located in the membranous atrioventricular septum near the tricuspid annulus. The His bundle 13 divides into a right bundle branch 8b and a left bundle branch 8a, and is formed by specialized fibers called "Purkinje fibers" 9. Purkinje fiber 9 can be described as rapidly conducting action potentials along the ventricular septum (VS), rapidly extending the depolarization wavefront through the remaining ventricular myocardium, and generating coordinated contractions of the ventricular myocardium.

[0005] While cardiac conduction system pacing is increasingly being used as an alternative to conventional pacing techniques, it has not been widely adopted for several reasons. For example, the cardiac conduction system pacing electrode must be positioned at a precise target location (e.g., within approximately 1 mm) within a portion or region of the cardiac conduction system, such as the His bundle, which can be difficult. Furthermore, adjusting cardiac conduction system pacing during treatment delivery can be challenging. Additionally, determining whether cardiac conduction system pacing is selective (i.e., pacing only the cardiac conduction system) or non-selective (i.e., pacing both the cardiac conduction system and myocardial tissue) can also be challenging. There is a desire to develop novel cardiac conduction system pacing systems, devices, and methods that overcome some of the drawbacks associated with previously performed cardiac conduction system pacing. Summary of the Invention

[0006] This disclosure relates generally to pacing cardiac conduction systems, such as the His-Purkinje system, for example, comprising the His bundle, left bundle branch, and right bundle branch. Specifically, this document describes exemplary apparatus and methods for providing adaptive cardiac conduction system pacing therapy that can selectively deliver pacing therapy in conjunction with conventional left ventricular pacing therapy. Such adaptive cardiac conduction system pacing therapy can determine and adjust the AV delay and VV delay (between cardiac conduction system pacing therapy and conventional left ventricular pacing therapy) based on near-field or far-field signals to provide effective cardiac therapy to the patient. Furthermore, such adaptive cardiac conduction system pacing therapy can switch between cardiac conduction system pacing therapy alone and cardiac conduction system pacing therapy combined with conventional left ventricular pacing therapy to provide effective cardiac therapy to the patient.

[0007] Exemplary devices and methods can be described as employing a three-chamber device solution for patients with indications for cardiac resynchronization therapy. This solution may include a standard right atrial lead, a 3830 or 3830D lead for pacing the His bundle or left bundle branch (LBB) region, and a left ventricular lead. Exemplary devices and methods may use one or more procedures for adaptive left ventricular pacing based on the efficacy of left ventricular activation from pacing the His bundle / LBB region. Such procedures may “adapt” between pacing the His bundle or LBB region only and pacing the His bundle or LBB region incorporating left ventricular pacing based on electrocardiographic efficacy metrics to pre-activate the left ventricle via conduction system pacing.

[0008] An exemplary implantable medical device may include multiple implantable electrodes for sensing and pacing a patient's heart. The multiple electrodes may include a left ventricular electrode capable of being positioned near the patient's left ventricle and a cardiac conduction system electrode capable of being positioned near a portion of the patient's cardiac conduction system. The device may also include a computing device with processing circuitry. The computing device may be operatively coupled to the multiple implantable electrodes and configured to initiate cardiac conduction system pacing therapy to the patient's cardiac conduction system using the cardiac conduction system electrode and to monitor the patient's local electrical activity using the left ventricular electrode during the delivery of cardiac conduction system pacing therapy using the cardiac conduction system electrode. The computing device may also be configured to switch between delivering cardiac conduction system pacing therapy to the patient's cardiac conduction system using the cardiac conduction system electrode and delivering left ventricular pacing therapy to the patient's left ventricle using the left ventricular electrode in response to the monitored local electrical activity.

[0009] An exemplary method may include: delivering cardiac conduction system pacing therapy to a patient's cardiac conduction system using a portion of an implanted cardiac conduction system electrode placed near the patient's cardiac conduction system; and monitoring the patient's local electrical activity using a left ventricular electrode placed near the patient's left ventricle during the delivery of cardiac conduction system pacing therapy using the cardiac conduction system electrode. The exemplary method may also include, in response to the monitored local electrical activity, switching between delivering cardiac conduction system pacing therapy to the patient's cardiac conduction system using the cardiac conduction system electrode and delivering left ventricular pacing therapy to the patient's left ventricle using the left ventricular electrode.

[0010] An exemplary implantable medical device may include multiple implantable electrodes for sensing and pacing a patient's heart. The multiple electrodes may include a left ventricular electrode capable of being positioned near the patient's left ventricle and a cardiac conduction system electrode capable of being positioned near a portion of the patient's cardiac conduction system. The device may also include a computing device with processing circuitry. The computing device may be operatively coupled to the multiple implantable electrodes and configured to determine a pacing AV delay used in delivering cardiac conduction system pacing therapy using the cardiac conduction system electrode. The pacing AV delay is the time interval between an atrial event and the delivery of cardiac conduction system pacing therapy. The computing device may also be configured to determine a pacing VV delay used in delivering cardiac conduction system pacing therapy using the cardiac conduction system electrode and in delivering left ventricular pacing therapy using the left ventricular electrode. The pacing VV delay is the time interval between the delivery of left ventricular pacing therapy and the delivery of cardiac conduction system pacing therapy. The computing device may also be configured to deliver cardiac conduction system pacing therapy using the pacing AV delay, or to deliver cardiac conduction system pacing therapy and left ventricular pacing therapy using both the pacing AV delay and the pacing VV delay.

[0011] An exemplary method may include using a cardiac conduction system electrode implanted near a portion of a patient's cardiac conduction system to determine a pacing AV delay used in delivering cardiac conduction system pacing therapy. The pacing AV delay is the time interval between an atrial event and the delivery of cardiac conduction system pacing therapy. The exemplary method may also include determining a pacing VV delay used in delivering cardiac conduction system pacing therapy using a cardiac conduction system electrode and in delivering left ventricular pacing therapy using a left ventricular electrode implanted near the patient's left ventricle. The pacing VV delay is the time interval between the delivery of left ventricular pacing therapy and the delivery of cardiac conduction system pacing therapy. The exemplary method may also include using a pacing AV delay to deliver cardiac conduction system pacing therapy, or using both a pacing AV delay and a pacing VV delay to deliver both cardiac conduction system pacing therapy and left ventricular pacing therapy.

[0012] Left bundle branch (LBB) pacing is important for treating bradycardia and heart failure, and for correcting left bundle branch block (HF-LBBB) in patients. The LBB can be considered the optimal region for physiological pacing. However, distinguishing between selective and non-selective capture of the LBB can be important for titrating optimal pacing at the LBB. Selective capture includes capture of the left bundle branch without local myocardial capture and is closer to physiological or normal activation of the left bundle branch compared to non-selective pacing. Non-selective pacing also involves cell-to-cell stimulation of the septum and can provide a slower global activation pathway than selective pacing. The illustrated devices and methods can utilize near-field electrogram-based diagnostic devices to differentiate between selective and non-selective capture, which may be important for long-term monitoring of the efficacy of left bundle branch pacing. When the goal is selective capture, if non-selective capture is detected, one or more pacing parameters (e.g., pacing output, vector, etc.) can be adjusted to achieve selective capture.

[0013] This article describes exemplary devices and methods for providing cardiac conduction system pacing therapy and determining whether such cardiac conduction system pacing therapy selectively or non-selectively captures the cardiac conduction system. Selective capture cardiac conduction system pacing therapy can be defined as pacing therapy that delivers pacing therapy only to the cardiac conduction system without directly delivering pacing therapy to the myocardium or muscular cardiac tissue. In other words, selective cardiac conduction system pacing therapy paces only the cardiac conduction system. Non-selective capture cardiac conduction system pacing therapy can be defined as pacing therapy that delivers pacing therapy to both the cardiac conduction system and directly to the myocardium or muscular cardiac tissue. In other words, non-selective cardiac conduction system pacing therapy paces both the cardiac conduction system and the myocardium or muscular cardiac tissue. Exemplary devices and methods using near-field signals can determine whether the delivered cardiac conduction system pacing therapy is selective or non-selective, which may help deliver effective cardiac treatment to patients.

[0014] An exemplary implantable medical device may include multiple implantable electrodes for sensing and pacing a patient's heart and a computing device with processing circuitry. The computing device may be operatively coupled to the multiple implantable electrodes and configured to initiate delivery of pacing therapy to the patient's heart, monitor near-field signals using the multiple implantable electrodes during a sensing period adjacent to the left bundle branch after delivery of pacing therapy, generate a derivative signal based on the near-field signals, and determine, based on the derivative signal, whether the pacing therapy selectively or non-selectively captures the cardiac conduction system.

[0015] An exemplary method may include: delivering pacing therapy to a patient’s heart using one or more of a plurality of implantable electrodes; monitoring near-field signals in a sensing period adjacent to the left bundle branch using the plurality of implantable electrodes after delivery of pacing therapy; generating a derivative signal based on the near-field signals; and determining whether the pacing therapy is selective.

[0016] The above overview is not intended to describe every embodiment or every implementation of this disclosure. A more complete understanding will become apparent and understood by taking into account the accompanying drawings and the following detailed description and claims. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the patient's heart (existing technology).

[0018] Figure 2A This is a conceptual diagram illustrating an exemplary treatment system (e.g., a three-chamber implantable medical device) configured to deliver treatment to a patient's heart using an implantable medical device (IMD) via His bundle or bundle branch pacing leads and leads placed in the right ventricle or right atrium.

[0019] Figure 2B This is a schematic diagram showing an exemplary His bundle or bundle branch pacing lead located in the His bundle in a cross-sectional view of the heart.

[0020] Figure 3A This is a conceptual diagram illustrating an exemplary treatment system (e.g., a dual-chamber implantable medical device) configured to deliver treatment to the heart of a patient with atrial fibrillation using an IMD via His bundle or bundle branch pacing leads and leads placed in the left ventricle.

[0021] Figure 3B This is a schematic diagram showing an example of a His bundle or bundle branch pacing lead located in the His bundle in a cross-sectional view of a heart using an IMD.

[0022] Figure 4 This is a conceptual diagram illustrating an example of a treatment system (e.g., a dual-chamber implantable medical device) configured to deliver treatment to a patient's heart using an IMD via His bundle or bundle branch pacing leads and leads placed in the left ventricle.

[0023] Figure 5 It is shown Figure 2A as well as Figures 3A to 4 A functional block diagram illustrating an example configuration of an implantable medical device.

[0024] Figure 6 yes Figures 1 to 5 A block diagram illustrating an exemplary method of adaptive cardiac conduction system pacing therapy that can be employed by the device.

[0025] Figure 7 It is certain Figure 6 A block diagram illustrating an exemplary process for AV delay.

[0026] Figure 8 It is certain Figure 6 A block diagram illustrating the VV delay method.

[0027] Figure 9 Is it to switch to Figure 6 A block diagram illustrating the combination of methods in cardiac conduction system and left ventricular pacing therapy.

[0028] Figure 10 It is a block diagram illustrating an exemplary method for determining whether pacemaker therapy has selectively captured the cardiac conduction system.

[0029] Figure 11 It is a block diagram illustrating the exemplary process of determining whether cardiac conduction system pacing therapy selectively or non-selectively captures the cardiac conduction system.

[0030] Figure 12A An electrocardiogram showing the left bundle branch capture by the selective cardiac conduction system was depicted.

[0031] Figure 12B An electrocardiogram showing the capture of the left bundle branch by the non-selective cardiac conduction system was depicted. Detailed Implementation

[0032] In the following detailed description of exemplary embodiments, reference is made to the accompanying drawings, which form part of this embodiment, and which illustrate specific embodiments that can be practiced by way of illustration. It should be understood that other embodiments may be utilized, and the structural scope may be changed, without departing from (e.g., still falling within) the scope of this disclosure herein.

[0033] Reference Figures 1 to 1 2. Description of exemplary apparatus and methods. It will be apparent to those skilled in the art that elements or processes of one embodiment can be used in combination with elements or processes of other embodiments, and that possible embodiments of such apparatus and methods using combinations of features set forth herein are not limited to those shown in the figures and / or the specific embodiments described herein. Furthermore, it will be appreciated that the embodiments described herein may include many elements that are not necessarily shown to scale. Still further, it will be appreciated that the timing of the processes and the size and shape of the various elements herein may be modified but still fall within the scope of this disclosure, although certain timings, one or more shapes and / or sizes, or element types may be preferred over others.

[0034] Figures 2A to 2BThis is a conceptual diagram illustrating an exemplary treatment system 10 that can be used to provide treatment to the heart 12 of a patient 14. The patient 14 is typically a person, but not necessarily a person. The treatment system 10 includes an IMD 16 coupled to leads 18, 20, 23 and a programmer 24. The IMD 16 may be an implantable pacemaker, cardioverter-defibrillator, and / or defibrillator that provides electrical signals to the heart 12, for example, via electrodes coupled to one or more of leads 18, 20, 23. Other non-limiting examples of the IMD 16 include: pacemakers with medical leads, implantable cardioverter-defibrillators (ICDs), intracardiac devices, leadless pacemakers (LPDs), subcutaneous ICDs (S-ICDs), and subcutaneous medical devices (e.g., neurostimulators, insertable monitoring devices, etc.).

[0035] Leads 18, 20, and 23 extend into the heart 12 of the patient 14 to sense the electrical activity of the heart 12 and / or deliver electrical stimulation to the heart 12. Figure 2A In the example shown, the right ventricle (RV) lead 18 extends through one or more veins (not shown), the superior vena cava (not shown), and the right atrium (RA) 26, and enters the right ventricle 28. The left ventricle (LV) coronary sinus lead 20 extends through one or more veins, the vena cava, the right atrium 26, and enters the coronary sinus 30, reaching the region adjacent to the free wall of the left ventricle 32 of the heart 12. The cardiac conduction system pacing lead 23 (e.g., His bundle or bundle branch pacing lead) extends through one or more veins and the vena cava, and enters the right atrium 26 of the heart 12 to pace the cardiac conduction system (e.g., Koch's triangle, septal wall, left bundle branch, right bundle branch, His bundle, etc.). In some embodiments, the cardiac conduction system pacing lead 23 may be positioned within approximately 1 mm of the Koch's triangle, septal wall, His bundle, or one or two bundle branches.

[0036] As used herein, cardiac conduction system pacing therapy refers to any pacing therapy configured to deliver pacing therapy (e.g., pacing pulses) to a cardiac conduction system, including, for example, the His bundle, left bundle branch, right bundle branch, etc. As used herein, the term "activation" refers to a sensed or paced event. For example, atrial activation can refer to an atrial sensing or event (As) or atrial pacing or atrial pacing artifact (Ap). Similarly, ventricular activation can refer to a ventricular sensing or event (Vs) or ventricular pacing or a ventricular pacing artifact (Vp), which can be described as a ventricular stimulation pulse. In some embodiments, activation intervals from As or Ap to Vs or Vp and from Vp to Vs can be detected. Specifically, activation intervals can include the pacing (Ap or Vp) to ventricular interval (LV or RV sensing) or the atrial sensing (As) to ventricular sensing interval (LV or RV sensing).

[0037] An example of a cardiac conduction system pacing therapy lead 23 (e.g., a His lead) could be SELECTSURE. ™ 3830. SELECTSURE ™ For a description of the 3830, please refer to the Medtronic model SELECTSURE. ™ 3830 Manual (2013). SELECTSURE ™ 3830 includes two or more conductors, with or without lumens.

[0038] The elongated conductor of the lead extends through the sealed feedthrough assembly and resides within the insulating tubular member of the lead, electrically connecting an electrical pulse generator (retained within the housing) to the helical tip electrode or cardiac conduction system electrode of the cardiac conduction system pacing therapy lead 23. The conductor may be formed of one or more conductive wires, such as MP35N alloy known to those skilled in the art, in a coiled or cable configuration, and the insulating tubular member may be any suitable medical-grade polymer, such as polyurethane, silicone rubber, or mixtures thereof. According to one exemplary embodiment, the flexible lead body extends a predetermined length (e.g., about 10 cm to about 20 cm, or about 15 cm to 20 cm) from the proximal end of the housing to the other end. The lead body is smaller than about 7 French (FR), but typically ranges from about 3 FR to 4 FR. In one or more embodiments, a lead body of about 2 FR to about 3 FR is used.

[0039] Cardiac conduction system pacing therapy can be performed via other leads. Another exemplary lead, including two or more pacing electrodes, can be used to deliver multi-site pacing pulses to the His bundle or one or two bundle branches. Multi-site pacing can be delivered simultaneously or sequentially, as described and illustrated in U.S. Patent Publication No. 2016 / 0339248, filed April 21, 2016, entitled “EFFICIENT DELIVERY OF MULTI-SITEPACING,” the disclosure of which is incorporated herein by reference in its entirety.

[0040] Because electrodes in multi-site or multi-point stimulation may be very close to each other, it may be important to detect and verify the effective capture of individual electrodes during the delivery of such treatments. Delivery of multi-site pacing pulses may include delivering pacing pulses to a first tissue site and a second tissue site, respectively, through a first pacing electrode and a second pacing electrode, all of which may occur within the same cardiac cycle.

[0041] Specifically, a lead different from the LV coronary sinus lead 20, configured to perform multi-site pacing, can be placed in the ventricular septum, with a first (distal) electrode located on the left side of the ventricular septum for left bundle branch pacing, and a second (proximal) electrode located on the right side of the ventricular septum for right bundle branch pacing. The inter-electrode distance can be defined as the distance between the first and second electrodes, or the distance between the electrodes. In some embodiments, the inter-electrode distance is at least about 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, or 8 mm. In some embodiments, the inter-electrode distance is at most about 15 mm, 14 mm, 13 mm, 12 mm, 11 mm, or 10 mm. For example, the inter-electrode distance can range from about 6 mm to 12 mm. Once pacing is delivered, both the left and right bundle branches can be stimulated, causing the two ventricles to be naturally or nearly naturally synchronized. Conversely, in conventional CRT, the ventricles may be described as not naturally synchronized.

[0042] A single lead comprising two (or more) pacing electrodes (e.g., cathodes) can deliver cathode pacing outputs at two separate locations (e.g., left bundle branch and right bundle branch), thus enabling simultaneous activation of both bundle branches.

[0043] While His bundle pacing is a primary candidate for physiological pacing, it can be difficult to implant, may have a relatively high pacing threshold, and may have an unstable long-term pacing threshold in patients with conduction disorders. Bundle branch pacing can bypass pathological areas and can have a low and stable pacing threshold. In some embodiments, only one bundle branch can be paced using pacing leads. One aspect of this disclosure provides simultaneous pacing of two bundle branches (e.g., bi-bundle branch pacing), which mimics the inherent activation propagation via the His bundle-Purkinje conduction system, e.g., pacing activation propagates through both bundle branches to both ventricles for synchronized contraction. On the other hand, conventional His bundle pacing typically paces the His bundle close to the bundle branch. In some embodiments, the IMD 16 may include one, two, or more electrodes located in one or more bundle branches configured for bundle branch pacing. In some embodiments, the IMD 16 may be an intracardiac pacemaker or a leadless pacing device (LPD).

[0044] As used herein, "leadless" refers to a device without leads extending from the patient's heart 12. In other words, the leads of a leadless device may not extend from the outside of the patient's heart to the inside. Some leadless devices can be introduced through a vein, but once implanted, the device has no or may not include any transvenous leads and can be configured to provide cardiac therapy without the use of any transvenous leads. In one or more embodiments, when the device housing is positioned in the atrium, the LPD for bundle pacing does not use leads to be operatively connected to an electrode positioned close to the diaphragm. Leadless electrodes can be coupled to the housing of the medical device without the use of leads between the electrode and the housing.

[0045] IMD 16 can be connected via an electrode to at least one of leads 18, 20, 23. Figures 2A to 2B (Not shown) to sense electrical signals accompanying depolarization and repolarization of the heart 12. In some examples, the IMD 16 delivers pacing pulses to the heart 12 based on the electrical signals sensed within the heart 12. The electrodes of the IMD 16 for sensing and pacing can be configured as unipolar or bipolar. The IMD 16 can also deliver defibrillation and / or cardioversion therapy via electrodes located on at least one of leads 18, 20, 23. The IMD 16 can detect arrhythmias of the heart 12, such as fibrillation of ventricles 28 and 32, and deliver defibrillation therapy to the heart 12 in the form of electrical pulses. In some examples, the IMD 16 can be programmed to deliver a therapeutic process, such as pulses with increasing energy levels, until the fibrillation of the heart 12 ceases. The IMD 16 can employ one or more fibrillation detection techniques known in the art to detect fibrillation.

[0046] In some examples, programmer 24 ( Figure 1 The programmer 24 can be a handheld computing device, a computer workstation, or a mobile phone. The programmer 24 may include a user interface that receives input from the user. The user interface may include, for example, a keypad and a display, which may be, for example, a cathode ray tube (CRT) display, a liquid crystal display (LCD), or a light-emitting diode (LED) display. The keypad may take the form of a numeric keypad associated with specific functions or a reduced set of keys. The programmer 24 may additionally or alternatively include a peripheral pointing device, such as a mouse, via which the user can interact with the user interface. In some embodiments, the display of the programmer 24 may include a touchscreen display, and the user can interact with the programmer 24 via the display. Through a graphical user interface on the programmer 24, the user can select one or more optimization parameters.

[0047] Furthermore, various pacing settings can be adjusted or configured based on various sensing signals. For example, various near-field and far-field signals can be sensed by one or more electrodes of the IMD 16 and / or other devices operatively coupled to it. For example, the VP to QRS end or offset within the near-field or far-field signals can be used to adjust or configure the AV delay for cardiac conduction system pacing therapy. Additionally, for example, the QRS within the near-field or far-field signals can be used to adjust or configure the VV delay between cardiac conduction system pacing therapy and conventional left ventricular pacing therapy. Furthermore, the left bundle branch ECG after the blanking period following ventricular pacing can be analyzed to determine whether cardiac conduction system pacing therapy is selective or non-selective. Therefore, near-field and / or far-field electrical signals can be used to detect QRS complexes. For example, far-field electrical signals can be sensed in a far-field electrogram (EGM) monitored by the IMD 16 and corresponding leads or a separate device (such as a subcutaneously implanted device). The QRS duration is the time from the detection of the Q wave until the end of the S wave.

[0048] As used herein, the term "far-field" electrical signal refers to the result of measuring cardiac activity using sensors or electrodes located outside the region of interest. For example, an ECG signal measured from electrodes located outside a patient's heart is an example of a far-field electrical signal of the patient's heart. Similarly, far-field electrical signals representing the electrical activity of a patient's cardiac chambers can be measured from sensors or electrodes located in adjacent chambers.

[0049] As used herein, the term "near-field" electrical signal refers to the result of measuring cardiac activity using sensors or electrodes located near the region of interest. For example, the EGM signal measured from an electrode located on the left side of a patient's ventricular septum is an example of the near-field electrical signal of the patient's left ventricular ventricular septum.

[0050] R-wave timing is the time at which the QRS complex is detected. Typically, R-wave timing includes the time using the maximum first derivative (or maximum R-wave value) of the rising edge of the R-wave. R-wave timing is also used in device channel marking to indicate R-wave duration or ventricular activation time.

[0051] Pacing-RV sensing or pacing-LV sensing (e.g., pacing to RV sensing or pacing to LV sensing) is the time interval from pacing (or pacing artifact) to RV or LV sensing. For example, if pacing-RV sensing is much longer than pacing-LV sensing, this could indicate that LV activation occurs much earlier than RV activation (hence the longer pacing-RV sensing), and RV pacing can be delivered synchronously with bundle pacing, so RV activation and LV activation can occur approximately simultaneously.

[0052] Users such as physicians, technicians, or other clinicians can interact with programmer 24 to communicate with IMD 16. For example, users can interact with programmer 24 to retrieve physiological or diagnostic information from IMD 16. Medtronic AMPLIAMRI™ CRT-D SURESCAN ™ An exemplary IMD 16 is described in the DTMB2D1 manual, which is incorporated herein by reference in its entirety. Users can also interact with programmer 24 to program IMD 16, for example, by selecting values ​​for the IMD's operational parameters.

[0053] The IMD 16 and the programmer 24 can communicate wirelessly using any technology known in the art. Examples of communication technologies may include, for example, low-frequency or radio-frequency (RF) telemetry, but other technologies are also contemplated. In some examples, the programmer 24 may include a programming lead that can be placed close to the patient's body near the IMD 16 implantation site to improve the quality or safety of communication between the IMD 16 and the programmer 24.

[0054] Figure 3A This is a conceptual diagram illustrating the IMD 16 and leads 18, 20, and 23 of the treatment system 10 in more detail. The three-chamber IMD 16 can be used for cardiac rhythm therapy and defibrillation or cardioversion therapy (CRT-D). Leads 18, 20, and 23 can be electrically connected to a stimulator, sensing module, or other modules of the IMD 16 via connector block 34. In some examples, the proximal ends of leads 18, 20, and 23 may include electrical contacts that are electrically connected to corresponding electrical contacts within connector block 34. Additionally, in some examples, leads 18, 20, and 23 can be mechanically connected to connector block 34 by means of retaining screws, connecting pins, or another suitable mechanical coupling mechanism.

[0055] Each of leads 18, 20, and 23 includes an elongated, insulated lead body that carries several concentric coiled conductors separated from each other by a tubular insulating sheath. In the illustrated example, an optional pressure sensor 38 and bipolar electrodes 40 and 42 are located near the distal end of lead 18. Additionally, bipolar electrodes 44 and 46 are located near the distal end of lead 20, and bipolar electrodes 48 and 50 are located near the distal end of lead 23. Figure 3AIn this embodiment, pressure sensor 38 is disposed within the right ventricle 28. Pressure sensor 38 can respond to absolute pressure within the right ventricle 28 and can be, for example, a capacitive or piezoelectric absolute pressure sensor. In other examples, pressure sensor 38 can be located in other regions of the heart 12 and can monitor pressure in one or more of these other regions, or pressure sensor 38 can be located elsewhere within or near the cardiovascular system of the patient 14 to monitor cardiovascular pressure associated with the mechanical contraction of the heart. Optionally, a pressure sensor in the pulmonary artery communicating with IMD 16 can be used.

[0056] Electrodes 40, 44, and 48 may be in the form of ring electrodes, and electrodes 42, 46, and 50 may be in the form of extendable and / or fixed spiral-tipped electrodes respectively mounted within insulated electrode heads 52, 54, and 56. Each of electrodes 40, 42, 44, 46, 48, and 50 may be electrically connected to a corresponding coil conductor in the coil conductor within the lead body of its associated lead 18, 20, and 23, and thereby connected to a corresponding electrical contact in an electrical contact at the proximal end of lead 18, 20, and 23.

[0057] Electrodes 40, 42, 44, 46, 48, and 50 can sense electrical signals accompanying depolarization and repolarization of the heart 12. These electrical signals are conducted to the IMD 16 via corresponding leads 18, 20, and 23. In some examples, the IMD 16 also delivers pacing pulses via electrodes 40, 42, 44, 46, 48, and 50 to induce depolarization of the cardiac tissue of the heart 12. In some examples, such as... Figures 3A to 3B As shown, the IMD 16 includes one or more housing electrodes, such as housing electrode 58, which may be integrally formed with or otherwise coupled to the outer surface of the hermetically sealed housing 60 of the IMD 16. In some examples, housing electrode 58 may be defined by an uninsulated portion of the outward-facing portion of the housing 60 of the IMD 16. Electrode 50 may be used for pacing and / or sensing of the His bundle or bundle branch tissues. Further separation between the insulating and non-insulated portions of the housing 60 may be used to define two or more housing electrodes. In some examples, housing electrode 58 substantially encompasses the entire housing 60. Any of electrodes 40, 42, 44, 46, 48, 50 may be used in conjunction with housing electrode 58 for unipolar sensing or pacing, or for bipolar sensing with two electrodes in the same pacing lead. In one or more embodiments, housing 60 may encapsulate a stimulation generator that generates cardiac pacing pulses and defibrillation or cardioversion shocks (see [link to relevant documentation]). Figure 5 ), and a sensing module for monitoring the patient's heart rhythm.

[0058] Leads 18, 20, and 23 may also include elongated electrodes 62, 64, and 66, which may be in the form of coils. The IMD 16 can deliver a defibrillation shock to the heart 12 via any combination of the elongated electrodes 62, 64, and 66 and the housing electrode 58. Electrodes 58, 62, 64, and 66 can also be used to deliver cardioversion pulses to the heart 12. Electrodes 62, 64, and 66 may be made of any suitable conductive material, such as, but not limited to, platinum, platinum alloys, or other materials known to be suitable for use in implantable defibrillation electrodes.

[0059] Pressure sensor 38 can be connected to one or more coil conductors within lead 18. Figure 3A In this embodiment, pressure sensor 38 is located on lead 18 further away from elongated electrode 62. In other examples, pressure sensor 38 may be positioned closer to elongated electrode 62, rather than distal to electrode 62. Furthermore, in other examples, pressure sensor 38 may be coupled to another of leads 20, 23, or to leads other than those carrying stimulation and sensing electrodes 18, 20, 23. Additionally, in some examples, pressure sensor 38 may be a stand-alone device implanted within heart 12 (such as within a septum separating right ventricle 28 from left ventricle 32, or within a septum separating right atrium 26 from left atrium 33). In such examples, pressure sensor 38 may communicate wirelessly with IMD 16.

[0060] Figure 3B IMD 16 is shown connected to leads 18, 20, 22, and 23. Right atrial (RA) lead 22 may extend through one or more veins and the vena cava and enter the right atrium 26 of heart 12. RA lead 22 may be connected to the three-chamber IMD 16, for example, using a Y-connector. IMD 16 can be used for cardiac rhythm therapy and defibrillation or cardioversion therapy (CRT-D). RA lead 22 may include electrodes that are the same as or similar to the electrodes of leads 18, 20, and 23, such as loop electrodes 40, 44, and 48, extendable spiral-tipped electrodes 42, 46, and 50, and / or elongated electrodes 62, 64, and 66 in coil form.

[0061] Figures 2A to 4 The configuration of the treatment system 10 shown is merely an example. In other examples, the treatment system may include epicardial leads and / or patch electrodes to replace or supplement it. Figures 2A to 4The transvenous leads 18, 20, 22 and / or cardiac conduction system pacing lead 23 shown herein, or other configurations shown, described, or incorporated herein by reference. Additionally, the IMD 16 does not need to be implanted in the patient 14. In examples where the IMD 16 is not implanted in the patient 14, the IMD 16 can deliver defibrillation shocks and other treatments to the heart 12 via percutaneous leads extending through the skin of the patient 14 to various locations inside or outside the heart 12.

[0062] In other examples of treatment systems that provide electrical stimulation to the heart 12, such systems may include any suitable number of leads coupled to the IMD 16, and each lead may extend to any location within or near the heart 12. Other examples of treatment systems may include, for instance, […]. Figures 2A to 4 The three transvenous leads shown are located, as well as another lead located in or near the left atrium 33. Figure 1 For example, other examples of treatment systems may include a single lead extending from IMD 16 into the right atrium 26 or the right ventricle 28, or two leads extending into one of the corresponding right ventricle 28 and right atrium 26. Figures 3A to 3B An example of this type of treatment system is shown. If treatment delivery requires four leads, the IS-1 connector can be used in conjunction with a Y-shaped adapter 25 extending from the RA port of the connector. The Y-shaped adapter allows two separate leads (e.g., a right atrial lead and a bundle pacing bundle lead) to extend from the two separate legs of the “Y”, while a single leg inserts into the connector block 34 on the IMD 16.

[0063] Figure 4 This is a concept diagram illustrating another example of the treatment system 70. Figure 4 The treatment system 70 shown can be used to provide defibrillation and pacing pulses to the heart 12. The treatment system 70 is similar to... Figures 2A to 2B or Figures 3A to 3B The treatment system 10 includes two leads 18 and 23 instead of three leads. The treatment system 70 can utilize an IMD 16 configured to deliver or perform dual-chamber pacing. Leads 18 and 23 are implanted in the right ventricle 28 and right atrium 26 to pace one or more portions of the cardiac conduction system, such as the His bundle or one or two bundle branches, respectively.

[0064] The cardiac conduction system pacing lead 23 can be in the form of a helical electrode (also known as a helical electrode) and can be positioned near, adjacent to, or within a region or part of the cardiac conduction system, such as the ventricular septum, Koch's triangle, His bundle, left and right bundle branch tissues, and / or right bundle branch tissues. The cardiac conduction system pacing lead 23 can be configured as a bipolar or quadripolar lead for use with a pacemaker device, a CRT-P device, or a CRT-ICD.

[0065] Figure 5 This is a functional block diagram of an exemplary configuration of the IMD 16, including a processor 80, a memory 82, a stimulation generator 84 (e.g., an electrical pulse generator or signal generation circuit), a sensing module 86 (e.g., a sensing circuit), a telemetry module 88, and a power supply 90. One or more components of the IMD 16, such as the processor 80, may be housed within the housing of the IMD 16 (e.g., within the housing of a pacemaker). The telemetry module 88, the sensing module 86, or both may be included in a communication interface. The memory 82 includes computer-readable instructions that, when executed by the processor 80, cause the IMD 16 and the processor 80 to perform various functions attributed to the IMD 16 and the processor 80 herein. The memory 82 may include any volatile, non-volatile, magnetic, optical, or electrical medium, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), electrically erasable programmable ROM (EEPROM), flash memory, or any other digital medium.

[0066] Processor 80 may include any one or more of the following: microprocessor, controller, digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), or equivalent discrete or integrated logic circuitry. In some examples, processor 80 may include multiple components (such as any combination of one or more microprocessors, one or more controllers, one or more DSPs, one or more ASICs, or one or more FPGAs) and other discrete or integrated logic circuitry. The functionality of processor 80 attributable to this document may be embodied in software, firmware, hardware, or any combination thereof. Processor 80 controls stimulation generator 84 to deliver stimulation therapy to heart 12 according to one or more selected treatment programs (e.g., optimization of AV delay, VV delay, VV delay, etc.), which may be stored in memory 82. Specifically, processor 80 may control stimulation generator 84 to deliver electrical pulses having amplitude, pulse width, frequency, or electrode polarity specified by the selected one or more treatment programs.

[0067] In some embodiments, the RA lead 22 may be operatively coupled to an electrode 61 that can be used to monitor or pace RA. The stimulation generator 84 may be electrically coupled to electrodes 40, 42, 44, 46, 48, 50, 58, 61, 62, 64, and 66, for example, via conductors of the respective leads 18, 20, 22, 23 or, in the case of housing electrodes 58, via electrical conductors disposed within the housing 60 of the IMD 16. The stimulation generator 84 may be configured to generate electrical stimulation therapy and deliver it to the heart 12. For example, the stimulation generator 84 may deliver a defibrillation shock to the heart 12 via at least two of electrodes 58, 62, 64, and 66. The stimulation generator 84 may deliver pacing pulses via ring electrodes 40, 44, 48 respectively coupled to leads 18, 20, and 23 and / or via helical electrodes 42, 46, or 50 respectively connected to leads 18, 20, or 23. Cardiac conduction system pacing therapy can be delivered via cardiac conduction system leads 23 connected to the atrial, RV, or LV connection ports of connector block 34. In some embodiments, cardiac conduction system pacing therapy can be delivered via leads 18 and / or 23. In some examples, the stimulation generator 84 delivers pacing, cardioversion, or defibrillation stimulation in the form of electrical pulses. In other examples, the stimulation generator 84 can deliver one or more of these types of stimulation in the form of other signals, such as sine waves, square waves, or other substantially continuous time signals.

[0068] The stimulation generator 84 may include a switching module, and the processor 80 may use the switching module to select, for example via a data / address bus, which of the available electrodes is used to deliver a defibrillation shock or pacing pulse. The switching module may include a switch array, a switch matrix, a multiplexer, or any other type of switching device suitable for selectively coupling stimulation energy to the selected electrode.

[0069] Sensing module 86 monitors signals from at least one of electrodes 40, 42, 44, 46, 48, 50, 58, 61, 62, 64, or 66 to monitor the electrical activity of heart 12, such as via electrocardiogram (ECG) signals and / or electrogram (EGM). Sensing module 86 may also include a switching module to select which of the available electrodes will be used to sense cardiac activity. In some examples, processor 80 may select the electrode acting as a sensing electrode via the switching module within sensing module 86, for example, by providing a signal via a data / address bus. In some examples, sensing module 86 includes one or more sensing channels, each of which may include an amplifier. In response to a signal from processor 80, the switching module may couple the output from the selected electrode to one of the sensing channels.

[0070] In some examples, one channel of the sensing module 86 may include an R-wave amplifier that receives signals from electrodes 40, 42 for pacing and sensing in the right ventricle 28 of the heart 12. Another channel may include another R-wave amplifier that receives signals from electrodes 44, 46 for pacing and sensing near the left ventricle 32 of the heart 12. In some examples, the R-wave amplifier may take the form of an automatic gain control amplifier that provides an adjustable sensing threshold based on the R-wave amplitude of the measured heart rate.

[0071] Additionally, in some examples, one channel of the sensing module 86 may include a P-wave amplifier that receives signals from electrodes 48, 50 used for pacing and sensing in the right atrium 26 of the heart 12. In some examples, the P-wave amplifier may take the form of an automatic gain control amplifier that provides an adjustable sensing threshold based on the P-wave amplitude of the measured heart rate. Examples of R-wave and P-wave amplifiers are described in U.S. Patent No. 5,117,824, entitled “APPARATUS FORMONITORING ELECTRICAL PHYSIOLOGIC SIGNALS,” issued June 2, 1992, to Keimel et al. Other amplifiers may also be used. In addition, in some examples, one or more sensing channels of sensing module 86 may be selectively coupled to housing electrode 58 or elongated electrode 62, 64 or 66 together with or in place of one or more electrodes 40, 42, 44, 46, 48 or 50, for example for unipolar sensing of R wave or P wave in any of the chambers 26, 28 or 32 of heart 12.

[0072] In some examples, the sensing module 86 includes a channel comprising an amplifier having a relatively wider passband than an R-wave amplifier or a P-wave amplifier, or a high-resolution amplifier having a relatively narrow passband for His bundle or bundle branch potential recording. Signals from selected sensing electrodes chosen for coupling to this broadband amplifier can be provided to a multiplexer and subsequently converted by an analog-to-digital converter into multi-bit digital signals for storage as an electrogram (EGM) in memory 82. In some examples, such storage of the EGM in memory 82 can be under the control of direct memory access circuitry. The processor 80 can employ digital signal analysis techniques to characterize the digitized signals stored in memory 82 to detect and classify the patient's heart rhythm from the electrical signals. The processor 80 can detect and classify the patient 14's heart rhythm by employing any of the numerous signal processing methods known in the art.

[0073] If the IMD 16 is configured to generate pacing pulses and deliver them to the heart 12, the processor 80 may include a pacemaker timing and control module, which may be embodied in hardware, firmware, software, or any combination thereof. The pacemaker timing and control module may include dedicated hardware circuitry such as an ASIC, separate from other processor 80 components such as a microprocessor, or a software module executed by components of the processor 80 that may be a microprocessor or an ASIC. The pacemaker timing and control module may include a programmable counter that controls the basic time interval associated with DDD, VVI, DVI, VDD, AAI, DDI, DDDR, VVIR, DVIR, VDDR, AAIR, DDIR, and other monoventricular and biventricular pacing modes. In the aforementioned pacing modes, “D” may indicate biventricular, “V” may indicate ventricle, “I” may indicate suppression pacing (e.g., no pacing), and “A” may indicate atrium. The first letter in the pacing mode may indicate the paced chamber, the second letter may indicate the chamber in which an electrical signal is sensed, and the third letter may indicate the chamber that provides a response to the sensed signal.

[0074] The intervals defined by the pacemaker timing and control module may include atrial and ventricular pacing escape intervals, refractory periods during which sensed P and R waves are ineffective for timing the restart of the escape interval, and the pulse width of the pacing pulse. As another example, the pacemaker timing and control module may define blanking periods and provide signals from sensing module 86 to blank one or more channels, such as amplifiers, for a period of time during and after the delivery of electrical stimulation to heart 12. The duration of these intervals may be determined by processor 80 in response to data stored in memory 82. The pacemaker timing and control module may also determine the amplitude of the cardiac pacing pulse.

[0075] During pacing, the escape interval counter within the pacemaker timing / control module can be reset upon sensing R and P waves. The stimulation generator 84 may include pacemaker output circuitry, selectively coupled, for example, via a switching module to any combination of electrodes 40, 42, 44, 46, 48, 50, 58, 61, 62, or 66 suitable for delivering bipolar or monopolar pacing pulses to one of the chambers of the heart 12. The processor 80 can reset the escape interval counter when pacing pulses are generated by the stimulation generator 84, thereby controlling the basic timing of cardiac pacing functions, including anti-tachyarrhythmia pacing.

[0076] In some examples, processor 80 can operate as an interrupt-driven device and respond to interrupts from the pacemaker timing and control module, where the interrupts may correspond to the occurrence of sensed P and R waves and the generation of cardiac pacing pulses. Any necessary mathematical calculations are performed by processor 80, and any updates to values ​​or intervals controlled by the pacemaker timing and control module of processor 80 may occur after such interrupts. A portion of memory 82 may be configured to hold multiple recirculation buffers capable of holding a series of measured intervals that can be analyzed by processor 80 in response to the occurrence of pacing or sensing interrupts to determine whether the patient's heart 12 is currently exhibiting an atrial or ventricular tachyarrhythmia.

[0077] Telemetry module 88 includes a means for communicating with another device such as programmer 24. Figure 2A This refers to any suitable hardware, firmware, software, or any combination thereof for communication. Under the control of processor 80, telemetry module 88 can receive downlink telemetry from programmer 24 and transmit uplink telemetry to programmer via an antenna that may be internal and / or external. Processor 80 can provide, for example, the data to be transmitted uplink to programmer 24 and control signals for the telemetry circuitry within telemetry module 88 via an address / data bus. In some examples, telemetry module 88 can provide the received data to processor 80 via a multiplexer.

[0078] The various components of the IMD 16 are connected to a power source 90, which may include a rechargeable or non-rechargeable battery. A non-rechargeable battery may be selected to last for several years, while a rechargeable battery may be inductively charged from an external device, for example, on a daily or weekly basis.

[0079] The exemplary device and method described herein can provide adaptive cardiac conduction system pacing therapy. When used in conjunction with cardiac conduction system pacing therapy, this exemplary adaptive cardiac conduction system pacing therapy can provide the timing configuration for both cardiac conduction system pacing and conventional left ventricular pacing. Furthermore, this exemplary adaptive cardiac conduction system pacing therapy can also provide switching from cardiac conduction system pacing therapy alone to a combination of cardiac conduction system pacing therapy and conventional left ventricular pacing therapy.

[0080] Figure 6 Depicting what can be made by Figures 1 to 5 The device utilizes an exemplary method 200 for adaptive cardiac conduction system pacing therapy. As shown, method 200 can determine the pacing AV delay 210 used in delivering cardiac conduction system pacing therapy using cardiac conduction system electrodes. The pacing AV delay is the time interval between a sensed or paced atrial event (e.g., atrial depolarization, a P wave on an electrocardiogram, etc.) and the delivery of cardiac conduction system pacing therapy (e.g., delivery of a pacing pulse to the cardiac conduction system).

[0081] Various exemplary procedures can be used to determine the pacing AV delay. Figure 7 Depicting the determination Figure 6 An exemplary procedure for AV delay 210. Figure 7 The process 210 may include measuring the intrinsic AV delay 212 using cardiac conduction system electrodes. Cardiac conduction system electrodes are electrodes configured to deliver cardiac conduction systems (e.g., electrodes located on cardiac conduction system leads 23 as described herein). The intrinsic AV delay is the time interval between a sensed intrinsic or spontaneous atrial event (e.g., atrial depolarization, a P wave on an electrocardiogram, etc.) and a sensed intrinsic or spontaneous ventricular event (e.g., depolarization of the left ventricle or both ventricles, an R wave on an electrocardiogram, etc.).

[0082] When testing various pacing AV delays, the measured intrinsic AV delay can be used. For example, process 210 may include delivering cardiac conduction system pacing therapy 214 to a patient's cardiac conduction system using cardiac conduction system electrodes at multiple different pacing AV delays less than the intrinsic AV delay. In this example, the multiple different pacing AV delays may be based on various percentages of the intrinsic AV delay. Each different percentage may be referred to as an AV delay percentage. For example, the multiple different pacing AV delays may range from about 20% to about 90% of the intrinsic AV delay. For example, the multiple different pacing AV delays may include a range of pacing AV delays based on different AV delay percentages spaced 5% or more apart from each other. In at least one embodiment, the multiple different pacing AV delays may include 20%, 30%, 40%, 50%, 60%, 70%, and 80% of the intrinsic AV delay.

[0083] Cardiac conduction system pacing therapy can be delivered for one or more cardiac cycles at each different pacing AV delay (or each different percentage of AV delay) to provide, for example, data of an appropriate sample size for evaluation. Process 210 can also monitor far-field electrical activity 216 during delivery of cardiac conduction system pacing therapy. Far-field electrical activity can be monitored by any electrode positioned outside the region of interest for cardiac conduction system pacing therapy. In at least one embodiment, far-field electrical activity can be monitored by a loop electrode positioned on a left ventricular lead located in the coronary sinus. In at least one embodiment, far-field electrical activity can be monitored by an external electrode disposed on the patient's torso skin.

[0084] Then, one of the multiple different pacing AV delays 218 can be selected based on the far-field electrical activity monitored during cardiac conduction system pacing therapy delivery at multiple different pacing AV delays. More specifically, one or more metrics can be derived or determined from the far-field electrical activity that can be used to determine the most effective or optimal pacing AV delay for cardiac conduction system pacing therapy. In at least one embodiment, the time period between cardiac conduction system pacing therapy delivery and the end of ventricular depolarization (e.g., QRS offset) can be determined for each of the multiple different pacing AV delays. The pacing AV delay or AV delay percentage that provides the shortest time period between cardiac conduction system pacing therapy delivery and the end of ventricular depolarization can then be selected.

[0085] As described herein, it should be understood that the selected pacing AV delay can be a percentage of the inherent AV delay, which may be referred to as the AV delay percentage. For example, the selected AV delay percentage could be 70% of the inherent AV delay. In this way, the inherent AV delay can be periodically measured by pausing any cardiac pacing treatment, and the pacing AV delay can be adjusted accordingly based on the selected AV delay percentage.

[0086] Therefore, process 210 can yield a selected AV delay for delivering cardiac conduction system pacing therapy. Method 200 may also include determining the VV delay 220 for cardiac conduction system and left ventricular pacing therapy. The VV delay can be the time interval between the delivery of cardiac conduction system pacing therapy and the delivery of left ventricular pacing therapy.

[0087] Various exemplary procedures can be used to determine the pacing VV delay 220. Figure 8 Depicting the determination Figure 6 An exemplary procedure for VV delay 220. Figure 8 The process 220 can deliver cardiac conduction system pacing therapy to the patient's cardiac conduction system at a selected AV delay and deliver left ventricular pacing therapy 222 at multiple different pacing VV delays. In this example, the multiple different pacing VV delays can include different time value ranges. For example, the multiple different pacing VV delays can be between about -80 milliseconds (ms) and about 80 ms. In other words, left ventricular pacing can be delivered between about 80 ms before and about 80 ms after the delivery of cardiac conduction system pacing therapy. For example, the multiple different pacing VV delays can include a range of pacing VV delays spaced apart from each other by a selected interval such as 10 ms. In at least one embodiment, the multiple different pacing VV delays can include -60 ms, -40 ms, -20 ms, 0 ms, 20 ms, 40 ms, and 60 ms.

[0088] Furthermore, cardiac conduction system pacing and left ventricular pacing can be delivered for one or more cardiac cycles at each different pacing VV delay to provide, for example, data of an appropriate sample size for evaluation. Process 220 can also monitor far-field electrical activity 224 during delivery of cardiac conduction system and left ventricular pacing. Far-field electrical activity can be monitored by any electrode positioned outside the region of interest for cardiac conduction system pacing. In at least one embodiment, far-field electrical activity can be monitored by a loop electrode positioned on a left ventricular lead located in the coronary sinus. In at least one embodiment, far-field electrical activity can be monitored by an external electrode disposed on the patient's torso skin.

[0089] Then, one of the multiple different pacing VV delays 226 can be selected based on the far-field electrical activity monitored during delivery of cardiac conduction system pacing and left ventricular pacing at multiple different pacing VV delays. More specifically, one or more metrics can be derived or determined from the far-field electrical activity that can be used to determine the most effective or optimal pacing VV delay for cardiac conduction system and left ventricular pacing. In at least one embodiment, the time period between the earliest pacing (e.g., cardiac conduction system pacing or left ventricular pacing depending on the current VV delay) and the end of ventricular depolarization (e.g., QRS duration, the time period between QRS initiation and QRS shift, etc.) can be determined for each of the multiple different pacing VV delays. The pacing VV delay that provides the shortest or narrowest time period between pacing and the end of ventricular depolarization (e.g., QRS duration) can then be selected.

[0090] Therefore, when using a combination of cardiac conduction system and left ventricular pacing therapy, process 220 can obtain a selected VV delay for delivering cardiac conduction system and left ventricular pacing therapy. As a result, if desired, method 200 can then be configured to deliver cardiac conduction system pacing therapy as well as the combined cardiac conduction system and left ventricular pacing therapy. Thus, method 200 can initiate or begin delivery of cardiac conduction system pacing therapy 230 independently, and monitor the patient's local electrical activity 240 using a left ventricular electrode during delivery of cardiac conduction system pacing therapy. Local electrical activity can be used to determine whether to switch to the combined cardiac conduction system and left ventricular pacing therapy 250. For example, various metrics can be derived or generated from local electrical activity, which can then be used to determine whether to switch to the combined cardiac conduction system and left ventricular pacing therapy 250.

[0091] Figure 9 Depicting switching to Figure 6An exemplary procedure 250 for a combination of cardiac conduction system and left ventricular pacing therapy. Procedure 250 includes determining 252 the interval between the delivery of cardiac conduction system pacing therapy and a peak in local activity monitored locally, and then comparing this interval to a threshold 254. The threshold may be between approximately 25 ms and approximately 75 ms. In at least one embodiment, the threshold is 50 ms. In other embodiments, the threshold may be greater than or equal to 25 ms, greater than or equal to 35 ms, greater than or equal to 45 ms, greater than or equal to 55 ms, etc., and / or less than or equal to 75 ms, less than or equal to 65 ms, less than or equal to 50 ms, etc. If the measured interval is greater than or equal to the threshold, it can be determined that cardiac conduction system pacing therapy may not be optimal or most effective, and therefore may be adjusted and / or may benefit from additional left ventricular pacing therapy. If the measured interval is less than the threshold, it can be determined that cardiac conduction system pacing therapy is effective, and the procedure may return to monitoring local electrical activity 252.

[0092] like Figure 9 As shown in process 250, if the interval is greater than or equal to a threshold, the cardiac conduction system pacing therapy 256 can be adjusted. For example, the cardiac conduction system pacing output can be increased (e.g., the amplitude or voltage can be increased, the pacing pulse train can be lengthened, the pacing frequency can be increased, the number of pulse trains per pulse can be increased, etc.). Furthermore, for example, the electrode vector for cardiac conduction system pacing therapy can be changed (e.g., the number of electrodes used to deliver cardiac conduction system pacing therapy can be increased, or different electrodes or different combinations of electrodes can be used to deliver cardiac conduction system pacing therapy). Simultaneously, process 250 can continue to monitor local electrical activity 252 and compare the interval with a threshold 258, and if the interval becomes less than the threshold, process 250 can return to delivering cardiac conduction system pacing therapy with the newly adjusted pacing output and monitoring local electrical activity.

[0093] If adjustments to the cardiac conduction system pacing output parameters do not result in an interval less than a threshold, process 250 can continue to cycle to adjust the output parameters until adjustments are exhausted 258. When further adjustment or increase in pacing output is not possible, pacing output parameter adjustments may be exhausted. In other words, cardiac conduction system pacing output may be exhausted when it is at its upper limit or maximum limit. When adjustments are exhausted, process 250 can proceed to deliver combined cardiac conduction system and left ventricular pacing therapy 259 according to previously determined AV and VV delays. Therefore, process 250 can switch from cardiac conduction system pacing therapy alone to a combination of cardiac conduction system pacing therapy and left ventricular pacing therapy.

[0094] Method 200 also includes, for example, measuring the inherent AV delay in the absence of pacing therapy delivery to periodically adjust the pacing AV delay 260 and using a previously determined percentage of AV delay to determine a new pacing AV delay.

[0095] The exemplary apparatus and methods described herein can also be configured to determine whether cardiac conduction system pacing therapy being delivered to a patient's cardiac conduction system selectively or non-selectively captures the patient's cardiac conduction system. Selective capture cardiac conduction system pacing therapy with cardiac conduction system can be defined as pacing therapy that delivers pacing therapy only to the cardiac conduction system without directly delivering pacing therapy to the myocardium or muscular cardiac tissue. In other words, selective cardiac conduction system pacing therapy paces only the cardiac conduction system. Non-selective capture cardiac conduction system pacing therapy with cardiac conduction system can be defined as pacing therapy that delivers pacing therapy to both the cardiac conduction system and also directly to the myocardium or muscular cardiac tissue. In other words, non-selective cardiac conduction system pacing therapy paces both the cardiac conduction system and the myocardium or muscular cardiac tissue. The exemplary apparatus and methods using near-field signals can determine whether the delivered cardiac conduction system pacing therapy is selective or non-selective, which may help deliver effective cardiac treatment to the patient.

[0096] Figure 10 An exemplary method 300 for determining whether cardiac conduction system pacing therapy has selectively captured the cardiac conduction system is described. Method 300 may include, for example, the methods described herein. Figures 1 to 5 One of the exemplary devices described is used to deliver cardiac conduction system pacing therapy 310 and to monitor near-field electrical activity 320 during the delivery of cardiac conduction system pacing therapy. Near-field electrical activity can be monitored via one or more implanted electrodes located near the left bundle branch.

[0097] Near-field electrical activity 320 can be monitored during a sensing period following the delivery of cardiac conduction system pacing therapy. The sensing period can be between approximately 25 ms and approximately 150 ms. In at least one embodiment, the sensing period is 50 ms. In other embodiments, the sensing period can be greater than or equal to 25 ms, greater than or equal to 35 ms, greater than or equal to 45 ms, greater than or equal to 55 ms, greater than or equal to 65 ms, etc., and / or less than or equal to 150 ms, less than or equal to 125 ms, less than or equal to 100 ms, less than or equal to 75 ms, less than or equal to 55 ms, etc.

[0098] Additionally, the sensing period may include a blanking period following the delivery of cardiac conduction system pacing therapy. The blanking period may be between approximately 5 ms and approximately 30 ms. In at least one embodiment, the blanking period is 20 ms. In other embodiments, the blanking period may be greater than or equal to 5 ms, greater than or equal to 10 ms, greater than or equal to 15 ms, etc., and / or less than or equal to 30 ms, less than or equal to 25 ms, less than or equal to 17 ms, etc.

[0099] In other words, after the delivery of cardiac conduction system pacing therapy, a blanking period of up to 20 ms can delay the measurement or monitoring of near-field electrical activity, which can then be measured or monitored within a sensing period of up to 50 ms.

[0100] A derivative signal 330 can be generated based on near-field electrical activity monitored during the sensing period. The derivative signal can be described as calculating the derivative of a near-field electrical signal (e.g., an electrocardiogram) by acquiring the differences between consecutive samples. In at least one embodiment, a 5-point derivative of the near-field signal is generated, for example, to provide a smoother derivative signal and eliminate the possibility of large variations due to local artifacts.

[0101] Method 300 can then determine, based on the derivative signal, whether pacing therapy is selective or non-selective capture of the cardiac conduction system 340. Determining whether pacing therapy is selective or non-selective capture of the cardiac conduction system based on the derivative signal can be done or performed in a variety of different ways and using a variety of different metrics. Figure 11 An exemplary process for determining whether cardiac conduction system pacing therapy selectively or non-selectively captures the cardiac conduction system is described 340.

[0102] like Figure 11 As shown, the number of changing events 342 within the derivative signal during the sensing period can be determined and then compared with a changing event threshold 344. In this example, the changing event threshold is 5. Therefore, if more than 5 changing events occur within the derivative signal during the sensing period, it can be determined that cardiac conduction system pacing therapy has selective capture 346. Conversely, if 5 or fewer changing events occur within the derivative signal during the sensing period, it can be determined that cardiac conduction system pacing therapy has non-selective capture 348. Although the changing event threshold is 5 in this example, the changing event threshold can be less than or greater than 5. For example, the changing event threshold can be between approximately 2 and approximately 10, depending on the length of the sensing time period, etc.

[0103] A change event can typically be described as an event in which the derivative signal changes sign from positive to negative or vice versa. For example, a minimum change threshold, such as 0.1 volts, can be used. Therefore, change events can be counted or determined for each sign change greater than 0.1 volts within the derivative signal during the sensing period. Although the minimum change threshold is 0.1 volts in this example, it can be less than or greater than 0.1 volts. For example, the minimum change threshold could be between approximately 0.05 volts and approximately 0.4 volts.

[0104] Figure 12A A left bundle branch electrocardiogram 351 showing selective capture of the cardiac conduction system is depicted. As shown, more than five change events occurred within a sensing period 352 following cardiac conduction system pacing therapy 350, thereby indicating selective capture of the cardiac conduction system. Figure 12B A left bundle branch electrocardiogram 353 showing non-selective capture of the cardiac conduction system is depicted. As shown, fewer than or equal to five change events occurred within a sensing period 352 following cardiac conduction system pacing therapy 350, thereby indicating non-selective capture of the cardiac conduction system.

[0105] Various examples have been described. These and other examples are within the scope of the appended claims. For example, the exemplary methods described herein can be implemented using single-chamber, dual-chamber, or triple-chamber pacemakers (e.g., CRT-P) or ICD (e.g., CRT-D) devices.

[0106] Exemplary Examples

[0107] While this disclosure is not limited thereto, an understanding of various aspects of this disclosure will be obtained through discussion of the specific exemplary embodiments provided below. Various modifications to the exemplary embodiments and additional embodiments of this disclosure will become apparent herein.

[0108] Example 1: An implantable medical device, comprising: Multiple implantable electrodes used to sense and pace a patient's heart, including: A left ventricular electrode that can be positioned near the patient's left ventricle; and Cardiac conduction system electrodes capable of being positioned near a portion of the patient's cardiac conduction system; and A computing device including processing circuitry, operatively connectable to multiple implanted electrodes, wherein the computing device is configured to: Using cardiac conduction system electrodes to initiate cardiac conduction system pacing therapy delivered to the patient's cardiac conduction system; Monitoring regional electrical activity of patients using left ventricular electrodes during cardiac conduction system pacing therapy with cardiac conduction system electrodes; and In response to monitored local electrical activity, the system switches between delivering cardiac conduction system pacing therapy to the patient's cardiac conduction system using cardiac conduction system electrodes and delivering left ventricular pacing therapy to the patient's left ventricle using left ventricular electrodes.

[0109] Example 2: A method comprising: Cardiac conduction system pacing therapy is delivered to the patient's cardiac conduction system using cardiac conduction system electrodes implanted near a portion of the patient's cardiac conduction system; During cardiac conduction system pacing therapy delivered using the aforementioned cardiac conduction system electrodes, local electrical activity of the patient is monitored using a left ventricular electrode implanted near the patient's left ventricle; and In response to monitored local electrical activity, the system switches between delivering cardiac conduction system pacing therapy to the patient's cardiac conduction system using cardiac conduction system electrodes and delivering left ventricular pacing therapy to the patient's left ventricle using left ventricular electrodes.

[0110] Example 3: The device according to Example 1 or the method according to Example 2, wherein the cardiac conduction system electrode is positioned near the patient's His bundle to deliver cardiac conduction system pacing therapy to the patient.

[0111] Example 4: The apparatus or method according to any one of Examples 1 to 3, wherein the cardiac conduction system electrode is positioned near the left bundle branch of the patient to deliver cardiac conduction system pacing therapy to it.

[0112] Example 5: The apparatus or method according to any one of Examples 1 to 3, wherein the computing device is further configured to determine the interval between the delivery of cardiac conduction system pacing therapy and the peak of monitored local electrical activity, wherein, in response to the monitored local electrical activity, switching to deliver cardiac conduction system pacing therapy to the patient's cardiac conduction system using cardiac conduction system electrodes and delivering left ventricular pacing therapy to the patient's left ventricle using left ventricular electrodes are both based on this interval.

[0113] Example 6: According to the apparatus or method of Example 5, the computing device is further configured to perform or the method further includes performing, in response to an interval greater than or equal to a threshold, adjusting the pacing output parameters of the cardiac conduction system.

[0114] Example 7: The apparatus or method according to Example 6, wherein the threshold is less than or equal to 50 milliseconds.

[0115] Example 8: According to the apparatus or method of Example 5, switching to delivery of both cardiac conduction system pacing therapy and left ventricular pacing therapy in response to monitored local electrical activity includes switching to delivery of both cardiac conduction system pacing therapy and left ventricular pacing therapy in response to an interval greater than or equal to a threshold.

[0116] Example 9: The computing device is further configured to perform the apparatus or method according to any one of Examples 1 to 8, further comprising: Periodically stop the delivery of pacing therapy and monitor the patient's intrinsic electrical activity using left ventricular electrodes during intrinsic cardiac electrical activation; and The pacing AV delay used in delivering cardiac conduction system pacing therapy using cardiac conduction system electrodes is determined based on the monitored intrinsic electrical activity, where the pacing AV delay is the time interval between an atrial event and the delivery of cardiac conduction system pacing therapy.

[0117] Example 10: An implantable medical device, comprising: Multiple implantable electrodes used to sense and pace a patient's heart, including: A left ventricular electrode that can be positioned near the patient's left ventricle; and Cardiac conduction system electrodes capable of being positioned near a portion of the patient's cardiac conduction system; and A computing device including processing circuitry, operatively connectable to multiple implanted electrodes, wherein the computing device is configured to: Determine the pacing AV delay used in delivering cardiac conduction system pacing therapy using cardiac conduction system electrodes, where the pacing AV delay is the time interval between an atrial event and the delivery of cardiac conduction system pacing therapy; Determine the pacing VV delay used when delivering cardiac conduction system pacing therapy using cardiac conduction system electrodes and when delivering left ventricular pacing therapy using left ventricular electrodes, wherein the pacing VV delay is the time interval between the delivery of left ventricular pacing therapy and the delivery of cardiac conduction system pacing therapy; and Pacing AV delay can be used to deliver cardiac conduction system pacing therapy, or pacing AV delay and pacing VV delay can be used to deliver cardiac conduction system pacing therapy and left ventricular pacing therapy.

[0118] Example 11: A method comprising: The pacing AV delay used in delivering cardiac conduction system pacing therapy is determined by using a cardiac conduction system electrode implanted near a portion of the patient’s cardiac conduction system, where the pacing AV delay is the time interval between an atrial event and the delivery of cardiac conduction system pacing therapy. Determine the pacing VV delay used in delivering cardiac conduction system pacing therapy using a cardiac conduction system electrode and in delivering left ventricular pacing therapy using a left ventricular electrode implanted near the patient's left ventricle, wherein the pacing VV delay is the time interval between the delivery of left ventricular pacing therapy and the delivery of cardiac conduction system pacing therapy; and Pacing AV delay can be used to deliver cardiac conduction system pacing therapy, or pacing AV delay and pacing VV delay can be used to deliver cardiac conduction system pacing therapy and left ventricular pacing therapy.

[0119] Example 12: The device according to Example 10 or the method according to Example 11, wherein the cardiac conduction system electrode is positioned near the patient's His bundle to deliver cardiac conduction system pacing therapy to the patient.

[0120] Example 13: The device according to Example 10 or the method according to Example 11, wherein the cardiac conduction system electrode is positioned near the left bundle branch of the patient to deliver cardiac conduction system pacing therapy to it.

[0121] Example 14: The apparatus or method according to any one of Examples 10 to 13, wherein determining the pacing AV delay includes: Using cardiac conduction system electrodes to initiate cardiac conduction system pacing therapy to the patient’s cardiac conduction system under multiple different pacing AV delays; Monitoring patients' far-field electrical activity during cardiac conduction system pacing therapy; and The pacing AV delay is selected from several different pacing AV delays based on the far-field electrical activity monitored during pacing therapy of the delivery cardiac conduction system.

[0122] Example 15: The apparatus or method according to Example 14, wherein selecting a pacing AV delay from a plurality of different pacing AV delays based on far-field electrical activity monitored during delivery of cardiac conduction system pacing therapy includes selecting a pacing AV delay from a plurality of different pacing AV delays that provides the shortest time period between delivery of cardiac conduction system pacing therapy and the end of ventricular depolarization.

[0123] Example 16: The apparatus or method according to any one of Examples 14 to 15, wherein determining the pacing AV delay further includes monitoring the patient’s far-field electrical activity prior to delivery of pacing therapy to provide an inherent AV delay between inherent atrial events and inherent ventricular events, wherein a plurality of different pacing AV delays are less than the inherent AV delay.

[0124] Example 17: The apparatus or method according to any one of Examples 14 to 16, wherein a left ventricular electrode is used to monitor far-field electrical activity.

[0125] Example 18: The apparatus or method according to any one of Examples 14 to 16, wherein at least one external electrode attached to the patient's skin is used to monitor far-field electrical activity.

[0126] Example 19: The apparatus or method according to any one of Examples 10 to 19, wherein determining the pacing VV delay includes: Under pacing AV delay and multiple different pacing VV delays, we initiated left ventricular pacing therapy delivered to the patient's left ventricle using left ventricular electrodes, and cardiac conduction system pacing therapy delivered to the patient's cardiac conduction system using cardiac conduction system electrodes. Monitoring patients' far-field electrical activity during delivery of left ventricular pacing and cardiac conduction system pacing; and The pacing VV delay is selected from several different pacing AV delays based on the electrical activity monitored during delivery of left ventricular pacing therapy and cardiac conduction system pacing therapy.

[0127] Example 20: The apparatus or method according to Example 19, wherein selecting a pacing VV delay from a plurality of different pacing VV delays based on far-field electrical activity monitored during delivery of left ventricular and cardiac conduction system pacing therapy includes selecting a pacing VV delay from a plurality of different pacing VV delays that provides the shortest time period between delivery of left ventricular and cardiac conduction system pacing therapy and the end of ventricular depolarization.

[0128] Example 21: An implantable medical device, comprising: Multiple implantable electrodes used to sense and pace a patient's heart; and A computing device including processing circuitry, the computing device being operatively connected to multiple implanted electrodes and configured to: Initiate pacing therapy delivered to the patient's heart; Multiple implantable electrodes were used to monitor near-field signals during a sensing period near the left bundle branch after pacing therapy was delivered. Generate derivative signals based on near-field signals; and The derivative signal is used to determine whether pacing therapy is a selective or non-selective capture of the cardiac conduction system.

[0129] Example 22: A method comprising: Pacing therapy is delivered to the patient's heart using one or more of a plurality of implantable electrodes; Multiple implantable electrodes were used to monitor near-field signals during a sensing period near the left bundle branch after pacing therapy was delivered. Generate derivative signals based on near-field signals; and The derivative signal is used to determine whether pacing therapy is a selective or non-selective capture of the cardiac conduction system.

[0130] Example 23: The method described in Example 22, wherein generating the derivative signal based on the near-field signal includes generating the 5-point derivative of the near-field signal.

[0131] Example 24: The apparatus according to Example 22 or the method according to Example 23, wherein determining whether pacing therapy has selective or non-selective capture of the cardiac conduction system based on the derivative signal includes determining the number of change events within the derivative signal during the sensing time period.

[0132] Example 25: The apparatus or method according to Example 24, wherein the change event is a change of 0.1 volts.

[0133] Example 26: The apparatus or method according to any one of Examples 24 to 25, wherein determining whether pacing therapy has selective or non-selective capture of the cardiac conduction system based on the derivative signal further includes determining that pacing therapy has selective capture of the cardiac conduction system if more than 5 change events exist during the sensing time period.

[0134] Example 27: In the apparatus or method according to any one of Examples 22 to 26, the computing device is further configured to perform or the method further includes adjusting one or more pacing settings of the pacing therapy in response to determining that the pacing therapy has a non-selective capture of the cardiac conduction system.

[0135] Example 28: The apparatus or method according to any one of Examples 22 to 27, wherein the sensing time period is less than or equal to 50 milliseconds.

[0136] Example 29: The apparatus or method according to any one of Examples 22 to 28, wherein a near-field signal is sensed after a blanking period following the delivery of pacing therapy.

[0137] Example 30: The apparatus or method according to Example 29, wherein the blanking time period is less than or equal to 20 milliseconds.

[0138] This disclosure is provided with reference to exemplary embodiments and examples and is not intended to be limiting. As previously stated, those skilled in the art will recognize that various other exemplary applications can utilize the beneficial features of the apparatus and methods described herein using the techniques described herein. Various modifications to the exemplary embodiments and examples will become apparent upon reference to this specification.

[0139] In one or more examples, the described techniques may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functionality may be stored as one or more instructions or code on a computer-readable medium and executed by a hardware-based processing unit. Computer-readable media may include non-transitory computer-readable media, which correspond to tangible media such as data storage media (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 is accessible by a computer).

[0140] The instructions can 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 arrays (FPGAs), or other equivalent integrated or discrete logic circuit systems. Therefore, as used herein, the term "processor" can refer to any of the foregoing structures or any other physical structures suitable for implementing the described techniques. Furthermore, this technique can be fully implemented in one or more circuit or logic elements.

[0141] All references and publications cited herein are expressly incorporated in their entirety by way of citation for all purposes, unless in any way directly contradict this disclosure.

[0142] Unless otherwise stated, all scientific and technical terms used herein have their common meaning in the art. The definitions provided herein are intended to facilitate understanding of certain terms frequently used herein and are not intended to limit the scope of this disclosure.

[0143] Unless otherwise specified, all numerical values ​​used in the specification and claims to represent characteristic dimensions, quantities, and physical properties are to be understood as being modified by the terms “precisely” or “about”. Therefore, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and appended claims are approximate values ​​that may vary within typical ranges of experimental error, depending on the desired properties sought by a person skilled in the art using the teachings disclosed herein.

[0144] The numerical range described by the endpoints includes all values ​​contained within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5) and any range within that range. In this document, the terms "at most" or "not greater than" a value (e.g., at most 50) include that value (e.g., 50), and the terms "not less than" a value (e.g., not less than 5) include that value (e.g., 5).

[0145] The terms “link” or “connection” refer to components being directly attached to each other (in direct contact with each other) or indirectly attached to each other (having one or more components between and attached to two components). Both terms can be modified by the interchangeable terms “operationally” and “operationally” to describe a link or connection configured to allow components to interact to perform at least some functions (e.g., a mobile user device can be operationally linked to a cellular network to send data to or receive data from it).

[0146] References to “one embodiment,” “implementation,” “certain embodiments,” or “some embodiments,” etc., mean that a particular feature, configuration, composition, or characteristic described in connection with that embodiment is included in at least one embodiment of this disclosure. Therefore, the appearance of such shortened terms throughout the document does not necessarily refer to the same embodiment of this disclosure. Furthermore, particular features, configurations, compositions, or characteristics may be combined in any suitable manner in one or more embodiments.

[0147] As used in this specification and the appended claims, the singular forms “a / an” and “the” cover embodiments having multiple indicators, unless expressly stated otherwise. As used in this specification and the appended claims, the term “or” is used in its usual sense, including “and / or”, unless expressly stated otherwise.

[0148] As used in this article, "have," "having," "include," "including," "comprise," and "comprising" are used in their open-ended sense and generally mean "including but not limited to." It should be understood that phrases such as "basically composed of" or "composed of" are categorized under "comprising."

[0149] The term “and / or” means one or all of the listed elements or a combination of at least two of the listed elements.

[0150] The phrases “at least one,” “including at least one,” and “one or more” that follow a list refer to any item in the list or any combination of two or more items in the list.

Claims

1. An implantable medical device, comprising: Multiple implantable electrodes for sensing and pacing a patient's heart, wherein the multiple implantable electrodes include: A left ventricular electrode capable of being positioned near the left ventricle of the patient; and Cardiac conduction system electrodes capable of being positioned near a portion of the patient's cardiac conduction system; and A computing device including processing circuitry, the computing device being operatively coupled to the plurality of implanted electrodes, wherein the computing device is configured to: The cardiac conduction system electrode is used to initiate cardiac conduction system pacing therapy to be delivered to the patient's cardiac conduction system; Monitoring the patient's local electrical activity using the left ventricular electrode during cardiac conduction system pacing therapy delivered with the cardiac conduction system electrode; and In response to monitored local electrical activity, the system switches between delivering cardiac conduction system pacing therapy to the patient's cardiac conduction system using the cardiac conduction system electrode and delivering left ventricular pacing therapy to the patient's left ventricle using the left ventricular electrode.

2. The device of claim 1, wherein the cardiac conduction system electrode is capable of being positioned near the patient's His bundle to deliver cardiac conduction system pacing therapy to the patient.

3. The device according to any one of claims 1 to 2, wherein the cardiac conduction system electrode is capable of being positioned near the left bundle branch of the patient to deliver cardiac conduction system pacing therapy thereto.

4. The apparatus of claim 1 or 2, wherein the computing device is further configured to determine the interval between the delivery of the cardiac conduction system pacing therapy and the peak of the monitored local electrical activity, wherein switching to deliver cardiac conduction system pacing therapy to the patient's cardiac conduction system using the cardiac conduction system electrodes and delivering left ventricular pacing therapy to the patient's left ventricle using the left ventricular electrodes are both based on the interval.

5. The apparatus of claim 4, wherein the computing device is further configured to adjust the cardiac conduction system pacing output parameters in response to the interval being greater than or equal to a threshold.

6. The apparatus of claim 5, wherein the threshold is less than or equal to 50 milliseconds.

7. The apparatus of claim 4, wherein switching to delivery of both cardiac conduction system pacing therapy and left ventricular pacing therapy in response to monitored local electrical activity comprises switching to delivery of both cardiac conduction system pacing therapy and left ventricular pacing therapy in response to the interval being greater than or equal to a threshold.

8. The apparatus according to claim 1 or 2, wherein the computing device is further configured to: Periodically stop the delivery of pacing therapy and monitor the patient's intrinsic electrical activity using the left ventricular electrode during intrinsic cardiac electrical activation; and The pacing AV delay used in delivering cardiac conduction system pacing therapy using the cardiac conduction system electrodes is determined based on the monitored intrinsic electrical activity, wherein the pacing AV delay is the time interval between an atrial event and the delivery of cardiac conduction system pacing therapy.

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