Systems, methods, and apparatus for determining capture of the cardiac conduction system

Abstract

Described herein are systems, methods, and apparatuses for determining capture of a cardiac conduction system by a ventricular to atrial (VfA) therapy. A VfA therapy can be delivered at a plurality of different A-V delays while the electrical activity of a patient is monitored. The electrical activity can then be utilized to determine whether the cardiac conduction system of the patient has been captured by the VfA therapy.

Description

[0001] The disclosure herein relates to systems, methods, and apparatus for determining, for example, the capture of the cardiac conduction system by atrioventricular (VfA) cardiac therapy.

[0002] Implantable medical devices (IMDs), such as implantable pacemakers, cardioverter-defibrillators, or pacemaker-cardioverter-defibrillators, deliver therapeutic electrical stimulation to the heart. IMDs can provide pacing to resolve bradycardia, or pacing or shock to terminate rapid arrhythmias such as tachycardia or fibrillation. In some cases, the device can sense the heart's inherent depolarization, detect arrhythmias based on (or the absence of) inherent depolarization, and, if an arrhythmia is detected based on inherent depolarization, control the delivery of electrical stimulation to the heart.

[0003] IMD can also offer cardiac resynchronization therapy (CRT), a form of pacing. CRT involves delivering pacing pulses to the left ventricle or both the left and right ventricles. The timing and location of the pacing pulses delivered to one or more ventricles can be selected to improve the coordination and efficiency of ventricular contractions.

[0004] In addition to the implantable medical device itself, the system used to implant the device may also include a workstation or other equipment. In some cases, these other devices assist physicians or other technicians in placing the intracardiac lead at a specific location on or within the heart. In other cases, the device provides the physician with information about the heart's electrical activity and the location of the intracardiac lead.

[0005] Determining whether the pacing electrode and the pacing therapy delivered therefrom have captured the cardiac conduction system or other cardiac tissue can be challenging when pacing electrodes are implanted and during the delivery of pacing therapy using such pacing electrodes. Summary of the Invention

[0006] The illustrative systems, devices, and methods described herein can be configured to assist a user (e.g., a physician) in determining, during and one or both periods after implantation, whether a pacing electrode, such as an atrial-to-ventricular (VfA) pacing electrode, and the cardiac therapy delivered therefrom, has captured the cardiac conduction system, rather than other cardiac tissue. Furthermore, the illustrative systems, devices, and methods described herein can be configured to assist a user (e.g., a physician) in determining whether a patient has AV blockage (e.g., the absence of natural conduction across the AV junction from the atrium to the ventricle).

[0007] In one or more embodiments, the system, apparatus, and method can be described as non-invasive. For example, in some embodiments, the system, apparatus, and method may not require or include implantable devices such as leads, probes, sensors, catheters, implantable electrodes, etc., to monitor or acquire multiple cardiac signals from the patient's tissues for determining capture of the cardiac conduction system (rather than capture of other cardiac tissues) and AV blockade. Alternatively, the system, apparatus, and method can use non-invasive electrical measurements using multiple external electrodes, for example, attached to the patient's skin around the torso. In one or more embodiments, the system, apparatus, and method can be described as non-invasive because such systems, apparatus, and methods can utilize implantable electrodes to monitor electrical activity for determining or assessing cardiac conduction system capture and / or AV blockade. Additionally, it should be understood that in some embodiments, both invasive and non-invasive devices and procedures can be used simultaneously.

[0008] Illustrative systems, devices, and methods may be described involving atrial-to-ventricular (VfA) pacing, as will be further described herein. VfA pacing may result in capture of only the myocardium without capture of the cardiac conduction system. Determining capture of the cardiac conduction system may be described as useful for determining or evaluating the placement of leads and / or pacing devices for delivering VfA pacing therapy. In one embodiment, illustrative systems, devices, and methods may generally be described as comprising delivering pacing with an AV delay or interval equal to 70% of the patient’s inherent AV delay, and gradually decreasing the AV delay or interval in steps of about 10 milliseconds (ms) to about 20 milliseconds until a predetermined minimum of 60 milliseconds. Electrical activity (e.g., activation time, electrogram, and electrocardiogram) from one or more of external electrode devices and interval electrode devices may be measured, and asynchrony information may be determined or generated based on the measured electrical activity.

[0009] In the absence of cardiac conduction system capture, asynchrony during shorter AV pacing intervals may increase due to intercellular conduction. In one or more embodiments, cardiac conduction system capture can be determined if the electrical asynchrony value (e.g., generated by electrical activity monitored from the electrode device) is low at the initial AV delay or interval, at pacing (e.g., standard deviation of activation time (SDAT) less than or equal to about 25 ms, mean left ventricular or thoracic alternative electrical activation time (LVAT) less than or equal to about 40 ms, etc.) and the electrical asynchrony value continues to remain low with shorter AV pacing intervals. In one or more embodiments, cardiac conduction system capture can be determined if the electrocardiogram (ECG) and / or electrophysiological record (EGM) during a short AV pacing interval is similar to that during a longer AV pacing interval in one or both aspects of QRS morphology and / or duration (e.g., closely matched, within tolerance levels, etc.).

[0010] An illustrative system may include an electrode device comprising a plurality of electrodes for monitoring electrical activity from a patient's tissues; and a computing device comprising a processing circuitry system coupled to the electrode device. The computing device may be configured to: monitor the electrical activity of the patient's heart using one or more of the plurality of electrodes during atrial-to-ventricular (VfA) pacing therapy delivered with a plurality of diagnostic AV delays, each of the plurality of diagnostic AV delays being less than the patient's inherent AV delay; and determine, based on the monitored electrical activity during the VfA pacing therapy delivered with the plurality of diagnostic AV delays, whether the VfA pacing therapy has captured the cardiac conduction system.

[0011] An illustrative method may include monitoring the electrical activity of a patient's heart using one or more of a plurality of electrodes during atrial-to-ventricular (VfA) pacing therapy delivered with a plurality of diagnostic AV delays, each of the plurality of diagnostic AV delays being less than the patient's inherent AV delay; and determining whether the VfA pacing therapy has captured the cardiac conduction system based on the electrical activity monitored during the VfA pacing therapy delivered with the plurality of diagnostic AV delays.

[0012] An illustrative implantable medical device may include multiple electrodes, including: a right atrial electrode positioned within the right atrium to deliver cardiac therapy to the right atrium of a patient's heart or to sense electrical activity in the right atrium; and a tissue-piercing electrode implanted through the right atrial endocardium and central fibrous tissue to deliver cardiac therapy to the left ventricle of a patient's heart or to sense electrical activity in the left ventricle. The illustrative device may further include: a therapy delivery circuit operatively coupled to the multiple electrodes to deliver cardiac therapy to the patient's heart; and a sensing circuit operatively coupled to the multiple electrodes to sense electrical activity in the patient's heart. The illustrative device may further include a controller including a processing circuitry operatively coupled to the therapy delivery circuit and the sensing circuit. The controller can be configured to deliver atrium-to-ventricle (VfA) pacing therapy with at least the tissue puncture electrode using a plurality of diagnostic AV delays, each of the plurality of diagnostic AV delays being less than the patient’s inherent AV delay, to monitor the patient’s cardiac electrical activity using one or more of the plurality of electrodes during the delivery of VfA pacing therapy with the plurality of diagnostic AV delays, and to determine whether the VfA pacing therapy has captured the cardiac conduction system based on the electrical activity monitored during the delivery of VfA pacing therapy with the plurality of diagnostic AV delays.

[0013] 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

[0014] Figure 1 This is a conceptual diagram of an illustrative cardiac therapy system that includes an intracardiac medical device implanted in the patient's heart and a separate medical device positioned outside the patient's heart.

[0015] Figure 2 yes Figure 1 An enlarged conceptual diagram of the anatomy of an intracardiac medical device and a patient's heart.

[0016] Figure 3 This is a conceptual diagram of a patient's heart in a standard 17-segment view showing various electrode implantation sites, intended for use with the illustrative systems and devices described herein.

[0017] Figure 4 This is a perspective view of an intracardiac medical device with a distal fixation and electrode assembly for use with the illustrative systems and apparatus described herein, the distal fixation and electrode assembly comprising a distal housing-based electrode implemented as a ring electrode.

[0018] Figure 5 This is a perspective view of another illustrative intracardiac medical device for use with the illustrative systems and apparatus described herein.

[0019] Figure 6 It is possible to enclose, for example Figure 1-2 Block diagrams of illustrative circuit systems within the housing of medical devices 4-5 to provide the functions and therapies described herein.

[0020] Figure 7 It is a flowchart illustrating the method for determining the capture of the cardiac conduction system.

[0021] Figures 8A-8C It is a graph depicting various scenarios of cardiac conduction capture, no cardiac conduction capture, and AV blockage, with decreasing AV delay or interval asynchrony.

[0022] Figure 9 It is a diagram of an illustrative system that includes electrode devices, display devices, and computing devices.

[0023] Figure 10-11 This is a diagram illustrating an external electrode device used to measure the surface potential of the torso. Detailed Implementation

[0024] In the following detailed description of illustrative embodiments, reference is made to the accompanying drawings, which form part of the specific embodiments and illustrate, by way of illustration, specific embodiments that can be practiced. It should be understood that other embodiments may be utilized and the scope of the structure may be changed without departing from (e.g., still falling within) the scope of this disclosure herein.

[0025] Reference Figure 1-11 This description illustrates systems, methods, and apparatuses. It will be apparent to those skilled in the art that elements or processes of one embodiment can be combined with elements or processes of other embodiments, and that possible embodiments of such systems, methods, and apparatuses using combinations of features set forth herein are not limited to the specific embodiments shown in the figures and / or 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 sizes and shapes 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.

[0026] Figure 1 An illustrative atrioventricular (VfA) cardiac therapy system is described, which can be configured to, for example, as described herein. Figure 1-11 The described systems and methods are used together. Although it should be understood that this disclosure can utilize one or both of leadless and leaded implantable medical devices, Figure 1The illustrative cardiac therapy system includes a leadless intracardiac medical device 10, which can be configured for single-chamber or dual-chamber therapy and implanted in a patient's heart 8. In some embodiments, the device 10 can be configured for single-chamber pacing and can be switched, for example, between single-chamber pacing and multi-chamber pacing (e.g., dual-chamber or triple-chamber pacing). As used herein, "intracardiac" means a device configured to be fully implanted within a patient's heart, for example, to provide cardiac therapy. A device 10 is shown implanted in a target implantation region 4 in the right atrium (RA) of a patient's heart 8. The device 10 may include one or more fixation members 20 anchoring the distal end of the device 10 to the atrial endocardium in the target implantation region 4. The target implantation region 4 may be located between the His bundle 5 and the coronary sinus 3 and may be adjacent to or immediately adjacent to the tricuspid valve 6. Device 10 can be described as an atrial-ventricular device because it can perform one of two things simultaneously, while typically placed in the right atrium: sensing electrical activity from one or both ventricles (e.g., the right ventricle, the left ventricle, or both ventricles, as appropriate) and providing therapy thereto. Specifically, device 10 may include a tissue-piercing electrode that can be implanted from the Koch's triangle region of the right atrium through the right atrial endocardium and central fibrous body into the base and / or septal region of the left ventricular myocardium of the patient's heart.

[0027] Device 10 can be described as a leadless implantable medical device. As used herein, "leadless" means a device without leads extending from the patient's heart 8. Further, although a leadless device may have leads, the leads do not extend from outside the patient's heart to inside the heart or from inside the heart to outside the heart. Some leadless devices can be introduced through a vein, but once implanted, the device has no or may not contain any transvenous leads and can be configured to provide cardiac therapy without the use of any transvenous leads. Further, when the device housing is positioned in the atrium, specifically, the leadless VfA device does not use leads to operatively connect to electrodes in the ventricle. Additionally, leadless electrodes can be coupled to the housing of the medical device without the use of leads between the electrodes and the housing.

[0028] Device 10 may include a dart electrode assembly 12 defining or having a straight axis extending from a distal region of device 10. The dart electrode assembly 12 may be placed or at least configured to pass through the atrial myocardium and central fibrous body and enter into the ventricular myocardium 14 or along the interventricular septum without completely penetrating the endocardial or epicardial surface of the ventricle. The dart electrode assembly 12 may carry or include an electrode at the distal region of the axis, such that the electrode can be positioned within the ventricular myocardium for sensing ventricular signals and delivering ventricular pacing pulses (e.g., depolarizing the left and / or right ventricles to induce contraction of the left and / or right ventricles). In some instances, the electrode at the distal region of the axis is a cathode electrode provided for use in a bipolar electrode pair for pacing and sensing. While the implantation region 4 shown allows one or more electrodes of the dart electrode assembly 12 to be positioned in the ventricular myocardium, it should be recognized that devices having the aspects disclosed herein can be implanted in other locations where appropriate for multi-chamber pacing (e.g., dual-chamber or triple-chamber pacing), single-chamber pacing with multi-chamber sensing, single-chamber pacing and / or sensing, or other clinical therapies and applications.

[0029] It should be understood that although the device 10 is described herein as comprising a single dart electrode assembly, the device 10 may comprise more than one dart electrode assembly, which is placed or configured to be placed through the atrial myocardium and central fibrous body and into the ventricular myocardium 14 or along the interventricular septum, without completely passing through the ventricular endocardium or epicardial surface. Additionally, each dart electrode assembly may carry or comprise more than one electrode in a distal region of the axis or in other regions along the axis (e.g., a proximal region or a central region).

[0030] The cardiac therapy system 2 may also include a separate medical device 50 (in Figure 1(Illustrated schematically) The individual medical device 50 can be positioned outside (e.g., subcutaneously) the patient's heart 8 and can be operatively coupled to the patient's heart 8 to deliver cardiac therapy thereto. In one example, the individual medical device 50 can be an extravascular ICD. In some embodiments, the extravascular ICD can include a defibrillation lead that includes or carries a defibrillation electrode. A therapy carrier can be present between the defibrillation electrode on the defibrillation lead and the housing electrode of the ICD. Further, one or more electrodes of the ICD can also be used to sense electrical signals related to the patient's heart 8. The ICD can be configured to deliver electrical shock therapy comprising one or more defibrillation or cardioversion shocks. For example, if an arrhythmia is sensed, the ICD can send pulses through the lead to shock the heart and restore its normal rhythm. In some instances, the ICD can deliver electrical shock therapy without placing the lead inside the heart or attaching the wire directly to the heart (subcutaneous ICD). Examples of vascular perivascular subcutaneous ICDs that can be used with System 2 described herein can be described in U.S. Patent No. 9,278,229 (Reinke et al.), published March 8, 2016.

[0031] In the case of electrical shock therapy (e.g., defibrillation shock delivered by defibrillation electrodes via defibrillation leads), a standalone medical device 50 (e.g., an extravascular ICD) may include control circuitry that uses a therapy delivery circuit to generate a defibrillation shock with any of a variety of waveform characteristics, including leading-edge voltage, slope, delivered energy, pulse phase, etc. The therapy delivery circuitry may, for example, generate monophasic, biphasic, or multiphasic waveforms. Additionally, the therapy delivery circuitry may generate defibrillation waveforms with varying amounts of energy. For example, the therapy delivery circuitry may generate a defibrillation waveform delivering a total of approximately 60-80 joules (J) of energy for subcutaneous defibrillation.

[0032] The individual medical device 50 may further include sensing circuitry. The sensing circuitry may be configured to acquire electrical signals sensed by one or more combinations of electrodes and to process the acquired signals. Components of the sensing circuitry may include analog components, digital components, or combinations thereof. The sensing circuitry may, for example, include one or more sense amplifiers, filters, rectifiers, threshold detectors, analog-to-digital converters (ADCs), etc. The sensing circuitry may convert the sensed signals into digital form and provide the digital signals to control circuitry for processing and / or analysis. For example, the sensing circuitry may amplify the signal from the sensing electrodes and convert the amplified signal into a multi-bit digital signal via an ADC, and then provide the digital signal to the control circuitry. In one or more embodiments, the sensing circuitry may also compare the processed signal with a threshold to detect the presence of atrial or ventricular depolarization (e.g., P wave or R wave) and indicate the presence of atrial depolarization (e.g., P wave) or ventricular depolarization (e.g., R wave) to the control circuitry.

[0033] Device 10 and a separate medical device 50 can cooperate to provide cardiac therapy to a patient's heart 8. For example, device 10 and the separate medical device 50 can be used to detect tachycardia, monitor tachycardia, and / or provide tachycardia-related therapy. For example, device 10 can wirelessly communicate with the separate medical device 50 to trigger an electric shock therapy using the separate medical device 50. As used herein, "wireless" means an operative coupling or connection between device 10 and the separate medical device 50 that does not use a metallic conductor. In one example, wireless communication can use a unique, signaling, or triggering electrical pulse provided by device 10 that is conducted through the patient's tissue and can be detected by the separate medical device 50. In another example, wireless communication can use the communication interface (e.g., an antenna) of device 10 to provide electromagnetic radiation that propagates through the patient's tissue and can be detected, for example, using the communication interface (e.g., an antenna) of the separate medical device 50.

[0034] Figure 2 yes Figure 1 An enlarged conceptual diagram of the anatomy of an intracardiac medical device 10 and a patient's heart 8. Specifically, device 10 is configured to sense electrical activity and / or deliver pacing therapy. Intracardiac device 10 may include a housing 30. Housing 30 may define internal components of device 10 (such as those used in conjunction with...). Figure 6The generally described sensing circuitry, therapy delivery circuitry, control circuitry, memory, telemetry circuitry, other optional sensors, and power supply reside in a hermetically sealed internal cavity. The housing 30 may contain (e.g., formed therefrom or derived therefrom) conductive materials such as titanium or titanium alloys, stainless steel, MP35N (a non-magnetic nickel-cobalt-chromium-molybdenum alloy), platinum alloys, or other biocompatible metals or metal alloys. In other examples, the housing 30 may contain (e.g., formed therefrom or derived therefrom) non-conductive materials, including ceramics, glass, sapphire, silicone, polyurethane, epoxy resin, acetyl copolymer plastics, polyetheretherketone (PEEK), liquid crystal polymers, or other biocompatible polymers.

[0035] In at least one embodiment, the housing 30 may be described as extending between the distal region 32 and the proximal region 34 and as defining a generally cylindrical shape, for example, to facilitate catheter delivery. In other embodiments, the housing 30 may be prismatic or any other shape to perform the functions and utilities described herein. The housing 30 may include, for example, a delivery tool interface member 26 defined or positioned at the proximal region 34 for engagement with a delivery tool during implantation of the device 10.

[0036] All or part of the housing 30 may serve as a sensing and / or pacing electrode during cardiac therapy. In the example shown, the housing 30 includes a proximal housing-based electrode 24 external to a proximal portion of the housing 30 (e.g., closer to the proximal region 34 than the distal region 32). When the housing 30 (e.g., defined by or formed of a conductive material such as titanium alloy or other examples listed above) is partially electrically insulated from a non-conductive material (e.g., a coating of parylene, polyurethane, silicone, epoxy resin, or other biocompatible polymers), one or more discrete regions of the conductive material are exposed to form or define a proximal housing-based electrode 24. When the housing 30 (e.g., defined by or formed of a non-conductive material such as ceramic, glass, or polymeric material) is present, a conductive coating or layer, such as titanium, platinum, stainless steel, or alloys thereof, can be applied to one or more discrete regions of the housing 30 to form or define a proximal housing-based electrode 24. In other instances, the proximal housing-based electrode 24 may be a component mounted or assembled onto the housing 30, such as a ring electrode. The proximal housing-based electrode 24 may be electrically coupled to the internal circuitry of the device 10, for example, through a conductive housing 30 or, when the housing 30 is a non-conductive material.

[0037] In the illustrated example, the proximal housing-based electrode 24 is positioned closer to the proximal housing region 34 than the distal housing region 32, and thus can be referred to as the proximal housing-based electrode 24. However, in other examples, the proximal housing-based electrode 24 may be positioned at other locations along the housing 30, for example, further away from the illustrated location.

[0038] At the distal region 32, the device 10 may include a distal fixation and electrode assembly 36, which may include one or more fixation members 20 and one or more dart electrode assemblies 12 of equal or unequal length. In one such example as shown, a single dart electrode assembly 12 includes a shaft 40 extending distally away from the distal region 32 of the housing, and one or more electrode elements, such as a tip electrode 42, at or near the free distal region of the shaft 40. The tip electrode 42 may have a conical or hemispherical distal tip with a relatively narrow tip diameter (e.g., less than about 1 mm) for penetration and through tissue layers without the need for sharp or beveled tips or needle-like tips.

[0039] The dart electrode assembly 12 can be configured to pierce one or more tissue layers to position the tip electrode 42 within a desired tissue layer (e.g., ventricular myocardium). Thus, the height 47 or length of the shaft 40 can correspond to the intended pacing site depth, and the shaft 40 can have relatively high compressive strength along its longitudinal axis to resist bending in the lateral or radial directions when pressed and inserted into the implantation region 4. If a second dart electrode assembly 12 is used, its length may not be equal to the intended pacing site depth and can be configured to act as an independent electrode for delivering pacing energy to and / or sensing signals from said tissue. In one embodiment, a longitudinal axial force can be applied to the tip electrode 42, for example, by applying a longitudinal thrust to the proximal region 34 of the housing 30, to advance the dart electrode assembly 12 into the tissue within the target implantation region.

[0040] Shaft 40 can be described as longitudinally non-compressible and / or elastically deformable in the transverse or radial direction when subjected to transverse or radial forces, allowing for temporary bending, for example, with tissue movement, but returning to its normal straight positioning when the transverse force decreases. Therefore, the dart electrode assembly 12 containing shaft 40 can be described as elastic. When shaft 40 is not exposed to any external force or is only exposed to a force along its longitudinal central axis, shaft 40 can maintain a straight, linear positioning as shown.

[0041] In other words, the shaft 40 of the dart electrode assembly 12 can normally be a straight member and can be rigid. In other embodiments, the shaft 40 can be described as relatively rigid, but still possessing limited flexibility in the lateral direction. Further, the shaft 40 can be non-rigid to allow some lateral bending with heart movement. However, in a relaxed state, when not subjected to any external force, the shaft 40 can maintain a straight positioning as shown to space the tip electrode 42 from the distal region 32 of the housing by at least the height or length 47 of the shaft 40.

[0042] The one or more fixation members 20 can be described as one or more “teeth” having a normal bending positioning. The teeth can be held in a distally extending position within the delivery tool. The distal tip of the teeth can penetrate cardiac tissue to a limited depth before elastically or resiliently bending back to the normal bending positioning (as shown) proximally upon release from the delivery tool. Further, the fixation member 20 can include one or more aspects described, for example, in U.S. Patent No. 9,675,579, issued June 13, 2017 (Grubac et al.) and U.S. Patent No. 9,119,959, issued September 1, 2015 (Rys et al.).

[0043] In some instances, the distal fixation and electrode assembly 36 includes a distal housing-based electrode 22. When using the device 10 as a pacemaker for multi-chamber pacing (e.g., dual-chamber or triple-chamber pacing) and sensing, the tip electrode 42 can serve as a cathode electrode paired with the proximal housing-based electrode 24, which acts as a return anode electrode. Alternatively, the distal housing-based electrode 22 can serve as a return anode electrode paired with the tip electrode 42 for sensing ventricular signals and delivering ventricular pacing pulses. In other instances, the distal housing-based electrode 22 can be a cathode electrode for sensing atrial signals and delivering pacing pulses to the atrial myocardium in the target implantation region 4. When the distal housing-based electrode 22 acts as an atrial cathode electrode, the proximal housing-based electrode 24 can serve as a return anode paired with the tip electrode 42 for ventricular pacing and sensing, and can also serve as a return anode paired with the distal housing-based electrode 22 for atrial pacing and sensing.

[0044] As illustrated in the diagram, in some pacing applications, the target implantation region 4 is along the atrial endocardium 18, typically below the AV node 15 and His bundle 5. The dart electrode assembly 12 may at least partially define the height 47 or length of the shaft 40 to penetrate the atrial endocardium 18 in the target implantation region 4, through the central fibrous body 16, and into the ventricular myocardium 14 without penetrating the ventricular endocardial surface 17. When the height 47 or length of the dart electrode assembly 12 is fully advanced into the target implantation region 4, the tip electrode 42 may be positioned within the ventricular myocardium 14, and the distal housing-based electrode 22 may be positioned in close contact with or very close to the atrial endocardium 18. In various examples, the dart electrode assembly 12 may have a total combined height 47 or length of the tip electrode 42 and shaft 40 of approximately 3 mm to approximately 8 mm. The diameter of the shaft 40 may be less than approximately 2 mm and may be approximately 1 mm or less, or even approximately 0.6 mm or less.

[0045] Device 10 may include acoustic and / or motion detectors 11 within housing 30. The acoustic or motion detectors 11 may be operatively coupled to one or more of control circuitry 80, sensing circuitry 86, or therapy delivery circuitry 84, as per [reference needed]. Figure 6 As described. The acoustic and / or motion detector 11 can be used to monitor mechanical activity, such as atrial mechanical activity (e.g., atrial contraction) and / or ventricular mechanical activity (e.g., ventricular contraction). In some embodiments, the acoustic and / or motion detector 11 can be used to detect right atrial mechanical activity. Non-limiting examples of the acoustic and / or motion detector 11 include one or both of an accelerometer and a microphone. In some embodiments, the mechanical activity detected by the acoustic and / or motion detector 11 can be used to supplement or replace electrical activity detected by one or more electrodes of the device 10. For example, the acoustic and / or motion detector 11 can be used in addition to or as an alternative to the proximal housing-based electrode 24.

[0046] The acoustic and / or motion detector 11 can also be used for rate response detection or to provide a rate-responsive IMD. Various techniques related to rate response can be described in U.S. Patent No. 5,154,170, entitled "Optimization for a rate-responsive cardiac pacemaker," issued October 13, 1992 (Bennett et al.), and U.S. Patent No. 5,562,711, entitled "Method and apparatus for rate-responsive cardiac pacing," issued October 8, 1996 (Yerich et al.).

[0047] In various embodiments, the acoustic and / or motion detector 11 can be used as a heart sound (HS) sensor and can be implemented as a microphone and / or a one-axis, two-axis, or three-axis accelerometer. In one embodiment, the acoustic and / or motion sensor 11 is implemented as a piezoelectric crystal mounted within a housing 30, the piezoelectric crystal responding to mechanical motion associated with heart sounds. Examples of other embodiments of acoustic sensors that can be adapted to be implemented with the techniques of this disclosure can be generally described in U.S. Patent Nos. 4,546,777 (Groch et al.), 6,869,404 (Schulhauser et al.), 5,554,177 (Kieval et al.), and 7,035,684 (Lee et al.).

[0048] In other words, various types of acoustic and / or motion sensors 11 can be used. For example, the acoustic and / or motion sensor 11 can be described as any implantable or external sensor that responds to one or more heart sounds and thereby is capable of generating or producing analog electrical signals that are time- and amplitude-dependent on the heart sounds. The analog signals can then be processed by the HS sensing module (which may include digital conversion) to obtain HS parameters, such as amplitude or relative time intervals, derived by the HS sensing module or control circuitry 80. The acoustic and / or motion sensor 11 and the HS sensing module can be incorporated into an IMD (e.g., device 10) capable of delivering CRT or another cardiac therapy being optimized, or can be implemented in a separate device with wired or wireless communication to another IMD or in an external programmer or computer used during pacing parameter optimization procedures as described herein.

[0049] Figure 3 This is a two-dimensional (2D) ventricular diagram 300 of a patient's heart (e.g., a top-down view), showing the left ventricle 320 and right ventricle 322 in a standard 17-segment view. Figure 300 defines or includes multiple zones 326 corresponding to different regions of the human heart. As shown, zones 326 are numbered from 1 to 17 (e.g., corresponding to 17 segments of a standard 17-segment human heart model, corresponding to 17 segments of the left ventricle of the human heart). Zones 326 of Figure 300 may include the anterior basal zone 1, anterior basal septum zone 2, subbasal septum zone 3, subbasal zone 4, subbasal lateral zone 5, anterior basal lateral zone 6, anterior mid-septum zone 7, anterior mid-septum zone 8, subbasal septum zone 9, submid-septum zone 10, submid-lateral mid-septum zone 11, anterior mid-lateral mid-septum zone 12, anterior vertex zone 13, vertex septum zone 14, subvertebral zone 15, lateral vertex zone 16, and apex zone 17. The inferior and anterior septal regions of the right ventricle 322, as well as the right bundle branch (RBB) 25 and the left bundle branch (LBB) 27, are also shown.

[0050] In some embodiments, any tissue-piercing electrode of this disclosure may be implanted in the base and / or septum region of the left ventricular myocardium of a patient's heart. Specifically, the tissue-piercing electrode may be implanted through the right atrial endocardium and central fibrous body from the Koch's triangle region of the right atrium. Once implanted, the tissue-piercing electrode can be positioned in a target implantation area such as the base and / or septum region of the left ventricular myocardium. Figure 1-2 Referring to Figure 300, the basal region includes one or more of the following: anterior basal region 1, anterior basal septum 2, subbasal septum 3, subbasal region 4, mid-anterior region 7, mid-anterior septum 8, mid-inferior septum 9, and mid-inferior region 10. Referring to Figure 300, the septal region includes one or more of the following: anterior basal septum 2, anterior basal septum 3, mid-anterior septum 8, mid-inferior septum 9, and superior septum 14.

[0051] In some embodiments, when implanted, the tissue-puncturing electrode may be positioned in the baso-septal region of the left ventricular myocardium. The baso-septal region may include one or more of the following: anterior baso-septal region 2, subbaso-septal region 3, anterior baso-septal region 8, and subbaso-septal region 9.

[0052] In some embodiments, when implanted, the tissue-puncturing electrode can be positioned in the superior / posterior basal septum region of the left ventricular myocardium. The superior / posterior basal septum region of the left ventricular myocardium may include a portion of one or more of the subbasal septum region 3 and the middle / inferior septum region 9 (e.g., only the subbasal septum region, only the middle / inferior septum region, or both). For example, the superior / posterior basal septum region may include a region 324 generally illustrated as a dashed boundary. As shown, the dashed boundary indicates the approximate location of the superior / posterior basal septum region, and its shape or size may vary slightly depending on the specific application.

[0053] Figure 4This is a three-dimensional perspective view of a device 10 capable of delivering pacing therapy and / or delivering sensed cardiac signals. As shown, the distal fixation and electrode assembly 36 includes a distal housing-based electrode 22 implemented as a ring electrode. The distal housing-based electrode 22 can be positioned in close contact with or operatively close to the atrial tissue when the fixation member teeth 20a, 20b, and 20c of the fixation member 20 engage with atrial tissue. The elastically deformable teeth 20a, 20b, and 20c can extend distally during delivery of the device 10 to the implantation site. For example, when the device 10 is ejected from the delivery tool, the teeth 20a, 20b, and 20c can pierce the atrial endocardial surface and bend back to their normal bending position when the teeth are no longer constrained within the delivery tool (as shown). When the teeth 20a, 20b, and 20c bend back to their normal position, the fixation member 20 can pull the distal fixation member and electrode assembly 36 toward the atrial endocardial surface. When the distal fixation member and electrode assembly 36 are “pulled” toward the atrial endocardium, the tip electrode 42 can be advanced through the atrial myocardium and central fibrous body and into the ventricular myocardium. The distal housing-based electrode 22 can then be positioned against or adjacent to the atrial endocardial surface.

[0054] The distal housing-based electrode 22 may comprise a conductive material (such as titanium, platinum, iridium, or alloys thereof) (e.g., formed therefrom). In one embodiment, the distal housing-based electrode 22 may be a single continuous ring electrode. In other instances, portions of the distal housing-based electrode 22 may be coated with an electrically insulating coating, such as parylene, polyurethane, silicone, epoxy, or other insulating coatings, to reduce the conductive surface area of ​​the electrode. For example, one or more sectors of the distal housing-based electrode 22 may be coated to separate two or more conductive exposed surface areas of the distal housing-based electrode 22. Reducing the conductive surface area of ​​the distal housing-based electrode 22, for example, by covering portions of the conductive area with an insulating coating, can increase the impedance of the distal housing-based electrode 22 and thereby reduce the current delivered during pacing pulses to capture myocardium (e.g., atrial myocardial tissue). Lower current consumption can save power to the device 10, such as one or more rechargeable or non-rechargeable batteries.

[0055] As described above, the distal housing-based electrode 22 can be configured as an atrial cathode electrode, which is used in conjunction with the proximal housing-based electrode 24 as a return anode to deliver pacing pulses to atrial tissue at the implantation site 4. Electrodes 22 and 24 can be used to sense atrial P waves for controlling atrial pacing pulses (delivery in the absence of a sensed P wave) and for controlling atrial-synchronized ventricular pacing pulses delivered using the tip electrode 42 as a cathode and the proximal housing-based electrode 24 as a return anode. In other embodiments, the distal housing-based electrode 22 can be combined with the cathode tip electrode 42 for ventricular pacing and sensing as a return anode.

[0056] Figure 5 This is a three-dimensional perspective view of another leadless intracardiac medical device 310, according to another example, which can be configured to determine cardiac conduction system capture, calibrate pacing therapy, and / or deliver pacing therapy for single-chamber or multi-chamber cardiac therapy (e.g., dual-chamber or triple-chamber cardiac therapy). Device 310 may include a housing 330 having an outer wall 335, shown as a cylindrical outer wall, extending from a distal region 332 of the housing to a proximal region 334 of the housing. Housing 330 may enclose an electronic circuitry system configured to perform single-chamber or multi-chamber cardiac therapy, which includes atrial and ventricular cardiac electrical signal sensing and pacing of the atrial and ventricular chambers. A delivery tool interface component 326 is shown on the proximal region 334 of the housing.

[0057] The distal fixation and electrode assembly 336 may be coupled to the distal region 332 of the housing. The distal fixation and electrode assembly 336 may include an electrically insulating distal member 372 coupled to the distal region 332 of the housing. A tissue-piercing electrode assembly 312 may extend remotely from the distal region 332 of the housing, and a plurality of non-tissue-piercing electrodes 722 may be directly coupled to the insulating distal member 372. As shown, the tissue-piercing electrode assembly 312 extends in a longitudinal direction remote from the distal region 332 of the housing and may be coaxial with the longitudinal central axis 331 of the housing 330.

[0058] The distal tissue puncture electrode assembly 312 may include an electrically insulating shaft 340 and a tip electrode 342 (e.g., a tissue puncture electrode). In some instances, the tissue puncture electrode assembly 312 may be described as a movable, fixed member comprising a helical shaft 340 and a distal cathode tip electrode 342. The helical shaft 340 may extend from a distal region 343 to a proximal region 341, which may be directly coupled to the insulating distal member 372. The helical shaft 340 may be coated with an electrically insulating material, such as parylene or other examples listed herein, to avoid sensing or stimulating cardiac tissue along the shaft length.

[0059] As described herein, the tip electrode 342 is located or positioned at the distal axial region 343 and can serve as a cathode electrode for delivering ventricular pacing pulses and sensing ventricular electrical signals using the proximal housing-based electrode 324 as a return anode when the tip electrode 342 is advanced toward or into ventricular tissue. The proximal housing-based electrode 324 can be an annular electrode of the outer housing 330 and can be defined by an uninsulated portion of the longitudinal sidewall 335. Other portions of the housing 330 that do not function as electrodes can be used in conjunction with the above description. Figure 4 The device 10 is coated with a similar electrically insulating material.

[0060] Using two or more tissue-puncture electrodes that penetrate into the LV myocardium (e.g., any type of tissue-puncture electrode) can be used for more localized pacing capture and can reduce ventricular pacing spikes, thereby affecting the capture of atrial tissue. In some embodiments, the multiple tissue-puncture electrodes may comprise two or more dart-shaped electrode assemblies (e.g., Figure 4 Electrode assemblies 12), helical electrodes. Non-limiting examples of multiple tissue-puncturing electrodes include two dart-shaped electrode assemblies, a helical electrode having a dart electrode assembly extending therethrough (e.g., through the center), or a double-wound helix. Multiple tissue-puncturing electrodes can also be used for bipolar or multipolar pacing.

[0061] In some embodiments, one or more tissue puncture electrodes (e.g., any type of tissue puncture electrode) penetrating into the LV myocardium can be multipolar tissue puncture electrodes. Multipolar tissue puncture electrodes may include one or more electroactive elements and electrodissociation elements, enabling bipolar or multipolar pacing from one or more tissue puncture electrodes. In other words, each tissue puncture electrode may contain one or more separate electrodes or electroactive segments or regions that are independent of each other.

[0062] Multiple non-tissue puncture electrodes 322 may be provided along the outer periphery of the insulating distal member 372, located on the outer periphery of the tissue puncture electrode assembly 312. The insulating distal member 372 may define a distally facing surface 338 of the device 310 and a circumferential surface 339 of the device 310 adjacent to the longitudinal sidewall 335 of the housing. The non-tissue puncture electrodes 322 may be formed of a conductive material such as titanium, platinum, iridium, or alloys thereof. In the illustrated embodiment, six non-tissue puncture electrodes 322 are radially spaced at equal distances along the outer periphery of the insulating distal member 372; however, two or more non-tissue puncture electrodes 322 may be provided.

[0063] The non-tissue puncture electrode 322 may be a discrete component, each held within a corresponding recess 374 in the insulating member 372, the size and shape of which are designed to match the non-tissue puncture electrode 322. In other examples, the non-tissue puncture electrode 322 may each be an uninsulated exposed portion of a monolithic member mounted within or above the insulating distal member 372. Intermediate portions of the monolithic member that do not function as electrodes may be insulated by the insulating distal member 372, or, if exposed to the surrounding environment, may be coated with an electrically insulating coating, such as parylene, polyurethane, silicone, epoxy, or other insulating coatings.

[0064] When the tissue-piercing electrode assembly 312 is advanced into the cardiac tissue, at least one non-tissue-piercing electrode 322 may be positioned against, in close contact with, or operatively close to the surface of the cardiac tissue to deliver pulses and / or sense cardiac electrical signals generated by the patient's heart. For example, when the tissue-piercing electrode assembly 312 is advanced into the atrial tissue and passes through the central fibrous body until the distal tip electrode 342 is positioned in direct contact with ventricular tissue (e.g., ventricular myocardium and / or a portion of the ventricular conduction system), the non-tissue-piercing electrode 322 may be positioned to contact the right atrial endocardial tissue for pacing and sensing in the atrium.

[0065] The non-tissue puncture electrode 322 can be coupled to the enclosure of the housing 330. This article will discuss... Figure 6 The described therapy delivery circuit and sensing circuit, in conjunction with the proximal housing-based electrode 324 serving as a return anode, act as cathode electrodes for delivering atrial pacing pulses and sensing atrial electrical signals (e.g., P waves). A switching circuit system included in the sensing circuit can be activated under the control of a control circuit to couple one or more non-tissue puncture electrodes to an atrial sensing channel. The distal non-tissue puncture electrodes 322 can be electrically isolated from each other, allowing each individual electrode of the electrodes 322 to be individually selected, either individually or in combination of two or more electrodes, to act as an atrial cathode electrode via the switching circuit system included in the therapy delivery circuit. The switching circuit system included in the therapy delivery circuit can be activated under the control of a control circuit to couple one or more non-tissue puncture electrodes of the non-tissue puncture electrodes 322 to an atrial pacing circuit. Two or more non-tissue puncture electrodes can be selected at once to serve as multi-center atrial cathode electrodes.

[0066] Certain non-tissue puncture electrodes 322 used for atrial pacing and / or atrial sensing can be selected based on atrial capture threshold testing, electrode impedance, P-wave signal intensity in cardiac electrical signals, or other factors. For example, a single non-tissue puncture electrode 322 or any combination of two or more separate said non-tissue puncture electrodes can be selected as the optimal combination of a cathode electrode providing a low pacing capture threshold amplitude and relatively high electrode impedance to achieve reliable atrial pacing using minimal current consumption from the power source.

[0067] In some cases, when the tissue-piercing electrode assembly 312 anchors the housing 330 at the implantation site 4, the distally facing surface 338 can uniformly contact the atrial endocardial surface. In this case, all electrodes 322 can be selected together to form an atrial cathode. Alternatively, every other electrode of the electrodes 322 can be selected together to form a multi-center atrial cathode with higher impedance, the atrial cathodes still being uniformly distributed along the distally facing surface 338. Alternatively, a subset of one or more electrodes 322 can be selected along one side of the insulating distal member 372 to provide pacing at a desired site that achieves the lowest pacing capture threshold due to the relative position of the electrodes 322 to the paced atrial tissue.

[0068] In other cases, depending on the positioning and orientation of the tissue-piercing electrode assembly 312 into the cardiac tissue, the distally facing surface 338 may be oriented at an angle relative to the adjacent endocardial surface. In this case, one or more of the non-tissue-piercing electrodes 322 may be positioned to make closer contact with the adjacent endocardial tissue than other non-tissue-piercing electrodes 322, which may be oriented at an angle away from the endocardial surface. By providing a plurality of non-tissue-piercing electrodes along the periphery of the insulating distal member 372, the angles of the tissue-piercing electrode assembly 312 and the distal housing region 332 relative to the cardiac surface (e.g., the right atrial endocardial surface) need not be substantially parallel. Anatomical and positioning differences may cause the distally facing surface 338 to be angled or tilted relative to the endocardial surface; however, the plurality of non-tissue-piercing electrodes 322 distributed along the periphery of the insulating distal member 372 increases the likelihood of good contact between one or more electrodes 322 and the adjacent cardiac tissue, thereby facilitating acceptable pacing thresholds and reliable cardiac event sensing using at least a subset of the plurality of electrodes 322. It may not be necessary to make circumferential contact or fixation along the entire outer periphery of the insulating distal member 372.

[0069] The non-tissue puncture electrode 322 is shown to each include a first portion 322a extending along a distally facing surface 338 and a second portion 322b extending along a circumferential surface 339. The first portion 322a and the second portion 322b may be continuous exposed surfaces such that the active electrode surface wraps around an outer peripheral edge 376 of the insulating distal member 372, the outer peripheral edge joining the distally facing surface 338 and the circumferential surface 339. The non-tissue puncture electrode 322 may include one or more electrodes 322 along the distally facing surface 338, one or more electrodes along the circumferential surface 339, one or more electrodes each extending along both the distally facing surface 338 and the circumferential surface 339, or any combination thereof. The exposed surface of each non-tissue puncture electrode in the non-tissue puncture electrode 322 may be flush with the corresponding distally facing surface 338 and / or circumferential surface. In other instances, each of the non-tissue puncture electrodes 322 may have a raised surface protruding from the insulating distal member 372. However, any raised surface of the electrode 322 may define a smooth or rounded non-tissue puncture surface.

[0070] The distal fixation and electrode assembly 336 can seal the distal region of the housing 330 and can provide a base for mounting the electrode 322 thereon. The electrode 322 may be referred to as a housing-based electrode. The electrode 322 may not be carried by an axis or other extension extending the active electrode portion (such as a distal tip electrode 342 located at the distal tip of a helical shaft 340 extending away from the housing 330) away from the housing 330. Other examples of non-tissue-piercing electrodes coupled to the distally facing surface and / or circumferential surface of an insulating distal member, as presented herein, include those described herein. Figure 4 The distal housing-based electrode 22 described in the device 10, as per this document... Figure 4 The device 10 describes a distal housing-based electrode, button electrode, other housing-based electrode, and other circumferential annular electrode extending circumferentially around the assembly 36. Any non-tissue puncture electrode located peripheral to the central tissue puncture electrode and directly coupled to the distal insulating member can be provided as a cathode electrode, individually, jointly, or in any combination, for delivering pacing pulses to adjacent cardiac tissue. When annular electrodes, such as the distal housing-based electrode 22 and / or circumferential annular electrodes, are provided, portions of the annular electrode may be electrically insulated by a coating to provide a plurality of distributed non-tissue puncture electrodes along the distally facing surface and / or circumferential surface of the insulating distal member.

[0071] Compared to the tissue-piercing electrode provided by distal fixation and electrode assembly 336, the non-tissue-piercing electrode 322 and other examples listed above are expected to provide more reliable and effective atrial pacing and sensing. The atrial cavity wall is relatively thin compared to the ventricular cavity wall. A tissue-piercing atrial cathode electrode may extend too deeply within the atrial tissue, resulting in unintentional continuous or intermittent capture of ventricular tissue. Because the ventricular signal has a greater signal intensity in the cardiac electrical signals received by the tissue-piercing atrial cathode electrode, which is physically closer to the ventricular tissue, the tissue-piercing atrial cathode electrode may interfere with the sensing of the atrial signal. The tissue-piercing electrode assembly 312 can be firmly anchored in the ventricular tissue to stabilize the implantation positioning of the device 310 and provide reasonable assurance that the tip electrode 342 performs sensing and pacing in the ventricular tissue while the non-tissue-piercing electrode 322 reliably performs pacing and sensing in the atrium. When the device 310 is implanted in the target implantation area 4 (e.g., as shown in the image), Figure 1-2 In the device 10 shown, the tip electrode 342 can reach the left ventricular tissue to pace the left ventricle, while the non-tissue-piercing electrode 322 provides pacing and sensing in the right atrium. The length of the tissue-piercing electrode assembly 312 from the distally facing surface 338 can be in the range of about 4 mm to about 8 mm to reach the left ventricular tissue. In some cases, the device 310 can achieve four-chamber pacing by delivering atrial pacing pulses from the atrial pacing circuit 83 via the non-tissue-piercing electrode 322 in the target implantation area 4 to achieve bi-atrial (right and left atrium) capture, and by delivering ventricular pacing pulses from the ventricular pacing circuit via the tip electrode 342 advanced from the target implantation area 4 into the ventricular tissue to achieve bi-ventricular (right and left ventricle) capture.

[0072] Figure 6 This is a block diagram of a circuit system, based on one example, that can be enclosed within a housing 30, 330 of device 10, 310 or the housing of any other medical device described herein to provide the function of sensing cardiac signals, determining capture and / or delivering pacing therapy. A separate medical device 50 (such as...) Figure 1The device (shown) may contain some or all of the same components that can be configured in a similar manner. The electronic circuitry enclosed within housings 30, 330 may include software, firmware, and hardware that collaboratively monitor atrioventricular and ventricular electrocardiographic signals, determine if cardiac capture has occurred, determine when cardiac therapy is needed, and / or deliver electrical pulses to the patient's heart according to programmed therapy patterns and pulse control parameters. The electronic circuitry may include control circuitry 80 (e.g., including processing circuitry), memory 82, therapy delivery circuitry 84, sensing circuitry 86, and / or telemetry circuitry 88. In some instances, devices 10, 310 include one or more sensors 90 for generating signals related to one or more physiological functions, states, or symptoms of the patient. For example, one or more sensors 90 may include patient activity sensors for determining the need for pacing therapy and / or controlling the pacing rate. Further, for example, one or more sensors 90 may include inertial measurement units (e.g., accelerometers) for measuring motion. Further, for example, one or more sensors 90 may include acoustic sensors for monitoring heart sounds. Furthermore, for example, one or more sensors 90 may include patient activity sensors, which may include accelerometers. An increase in the patient's metabolic demand due to an increase in activity as indicated by the patient activity sensor can be determined using the patient activity sensor. In other words, devices 10, 310 may include additional sensors 90 for sensing signals from the patient to determine whether and / or control the delivery of electrical stimulation therapy by the therapy delivery circuit 84.

[0073] Power supply 98 can provide power as needed to the circuitry of devices 10, 310 that include each of components 80, 82, 84, 86, 88, 90. Power supply 98 may include one or more energy storage devices, such as one or more rechargeable or non-rechargeable batteries. The connections between power supply 98 and each of components 80, 82, 84, 86, 88, 90 (not shown) can be understood from the general block diagram shown to a person skilled in the art. For example, power supply 98 may be coupled to one or more charging circuits included in therapy delivery circuitry 84 to provide power for charging a holding capacitor included in therapy delivery circuitry 84, which is discharged at appropriate times under the control of control circuitry 80 to deliver pacing pulses, for example, according to a dual-chamber pacing mode (such as DDI(R)). Power supply 98 may also be coupled to components of sensing circuitry 86 (such as sensing amplifiers, analog-to-digital converters, switching circuitry, etc.), sensor 90, telemetry circuitry 88, and memory 82 to provide power to various circuits.

[0074] The illustrated functional blocks represent the functions included in devices 10, 310, and may include any discrete and / or integrated electronic circuit components implementing analog and / or digital circuitry capable of producing the functions attributed to the medical devices 10, 310 described herein. Each component may include processing circuitry systems (such as application-specific integrated circuits (ASICs), electronic circuitry, processors (shared, dedicated, or grouped), and memory), combinational logic circuitry, state machines, or other suitable components or combinations thereof providing the described functions, executing one or more software or firmware programs. The specific form of software, hardware, and / or firmware used to implement the functions disclosed herein will be determined primarily by the specific system architecture employed in the medical device and the specific detection and therapy delivery methods used by the medical device.

[0075] Memory 82 may comprise any volatile, non-volatile, magnetic, or electrically non-transitory computer-readable storage 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 memory device. Furthermore, memory 82 may comprise a non-transitory computer-readable medium storing instructions that, when executed by one or more processing circuits, cause control circuitry 80 and / or other processing circuitry systems to determine cardiac conduction system capture and / or perform single-chamber, dual-chamber, or triple-chamber calibrated pacing therapy (e.g., single-chamber or multi-chamber pacing) or other cardiac therapeutic functions attributed to devices 10, 310 (e.g., sensing or delivery therapy). The non-transitory computer-readable medium storing instructions may comprise any of the media listed above.

[0076] The control circuit 80 can communicate, for example, via a data bus with the therapy delivery circuit 84 and the sensing circuit 86 to sense cardiac electrical signals and control the delivery of cardiac electrical stimulation therapy in response to sensed cardiac events (e.g., P waves and R waves, or their absence). The tip electrodes 42, 342, the distal housing-based electrodes 22, 322, and the proximal housing-based electrodes 24, 324 can be electrically coupled to the therapy delivery circuit 84 for delivering electrical stimulation pulses to the patient's heart, and electrically coupled to the sensing circuit 86 for sensing cardiac electrical signals.

[0077] Sensing circuit 86 may include an atrial (A) sensing channel 87 and a ventricular (V) sensing channel 89. Distal housing-based electrodes 22, 322 and proximal housing-based electrodes 24, 324 may be coupled to the atrial sensing channel 87 to sense atrial signals, such as P waves associated with atrial myocardial depolarization. In instances including two or more selectable distal housing-based electrodes, sensing circuit 86 may include a switching circuit system for selectively coupling one or more of the available distal housing-based electrodes to a cardiac event detection circuitry system contained in the atrial sensing channel 87. The switching circuit system may include a switch array, switch matrix, multiplexer, or any other type of switching device suitable for selectively coupling components of sensing circuit 86 to selected electrodes. Tip electrodes 42, 324 and proximal housing-based electrodes 24, 324 may be coupled to the ventricular sensing channel 89 to sense ventricular signals, such as R waves associated with ventricular myocardial depolarization.

[0078] Each of the atrial sensing channel 87 and the ventricular sensing channel 89 may include a cardiac event detection circuitry for detecting P waves and R waves, respectively, from cardiac electrical signals received by the respective sensing channel. The cardiac event detection circuitry included in each of channels 87 and 89 may be configured to amplify, filter, digitize, and rectify the cardiac electrical signals received from selected electrodes to improve signal quality for detecting cardiac electrical events. The cardiac event detection circuitry within each channel 87 and 89 may include one or more sensing amplifiers, filters, rectifiers, threshold detectors, comparators, analog-to-digital converters (ADCs), timers, or other analog or digital components. The cardiac event sensing thresholds, such as P wave sensing thresholds and R wave sensing thresholds, may be automatically adjusted by each respective sensing channel 87 and 89 under the control of the control circuitry 80, for example, based on a timing period and sensing thresholds stored in memory 82 and / or controlled by the hardware, firmware, and / or software of the control circuitry 80 and / or the sensing circuitry 86, as determined by the control circuitry 80.

[0079] When a cardiac electrical event is detected based on a sensing threshold crossing, sensing circuit 86 can generate a sensed event signal that is transmitted to control circuit 80. For example, atrial sensing channel 87 can generate a P-wave sensed event signal in response to a P-wave sensed threshold crossing. Ventricular sensing channel 89 can generate an R-wave sensed event signal in response to an R-wave sensed threshold crossing. Control circuit 80 can use the sensed event signals to set a pacing escape interval timer that controls the basic time interval used to schedule cardiac pacing pulses. Depending on the specific programmed pacing mode, the sensed event signals can trigger or suppress pacing pulses. For example, a P-wave sensed event signal received from atrial sensing channel 87 can cause control circuit 80 to suppress scheduled atrial pacing pulses and schedule ventricular pacing pulses with a programmed atrioventricular (AV) pacing interval. If an R-wave is sensed before the AV pacing interval expires, the ventricular pacing pulse can be suppressed. If the AV pacing interval is terminated before the control circuit 80 receives the R-wave sensing event signal from the ventricular sensing channel 89, the control circuit 80 can use the therapy delivery circuit 84 to deliver a scheduled ventricular pacing pulse synchronized with the sensed P wave.

[0080] In some instances, devices 10, 310 can be configured to deliver various pacing therapies, including bradycardia pacing, cardiac resynchronization therapy, post-shock pacing, and / or tachycardia-related therapies (such as ATP). For example, devices 10, 310 can be configured to detect non-sinus tachycardia and deliver ATP. Control circuitry 80 can determine cardiac event time intervals, such as the PP interval between consecutive P-wave sensed event signals received from atrial sensing channel 87, the RR interval between consecutive R-wave sensed event signals received from ventricular sensing channel 89, and the PR and / or RP intervals received between P-wave sensed event signals and R-wave sensed event signals. These intervals can be compared with tachycardia detection intervals to detect non-sinus tachycardia. Tachycardia can be detected in a given cardiac chamber based on a threshold number of detected tachycardia detection intervals.

[0081] The therapy delivery circuit 84 may include an atrial pacing circuit 83 and a ventricular pacing circuit 85. Each pacing circuit 83, 85 may include a charging circuit system, one or more charge storage devices (such as one or more low-voltage holding capacitors), an output capacitor, and / or a switching circuit system that controls when the one or more holding capacitors are charged and discharged across the output capacitor to deliver pacing pulses to the pacing electrode vector coupled to the respective pacing circuit 83, 85. Tip electrodes 42, 342 and proximal housing-based electrodes 24, 324 may be coupled as bipolar cathodes and anodes to the ventricular pacing circuit 85 to deliver ventricular pacing pulses, for example, upon the expiration of the AV or VV pacing interval set by control circuitry 80 for providing atrial synchronizing ventricular pacing and a basic lower ventricular pacing rate.

[0082] Atrial pacing circuit 83 can be coupled to distal housing-based electrodes 22, 322 and proximal housing-based electrodes 24, 324 to deliver atrial pacing pulses. Control circuit 80 can set one or more atrial pacing intervals based on a programmed lower pacing rate or a temporarily lower rate set according to a pacing rate indicated by a rate responsiveness sensor. If the atrial pacing interval is cut off before a P-wave sensed event signal is received from atrial sensing channel 87, the atrial pacing circuit can be controlled to deliver atrial pacing pulses. Control circuit 80 initiates an AV pacing interval in response to the delivered atrial pacing pulses to provide synchronized multi-chamber pacing (e.g., dual-chamber or triple-chamber pacing).

[0083] The therapy delivery circuit 84 can charge the holding capacitors of the atrial or ventricular pacing circuits 83, 85 to a programmed pacing voltage amplitude and discharge the capacitors for a programmed pacing pulse width, based on control signals received from the control circuit 80. For example, the pacing timing circuit included in the control circuit 80 may include a programmable digital counter, set by the microprocessor of the control circuit 80, to control the basic pacing interval associated with various single-chamber or multi-chamber pacing (e.g., dual-chamber or triple-chamber pacing) modes or anti-tachycardia pacing sequences. The microprocessor of the control circuit 80 can also set the amplitude, pulse width, polarity, or other characteristics of the cardiac pacing pulses based on programmed values ​​stored in memory 82.

[0084] Control parameters for sensing cardiac events and controlling the delivery of pacing therapy, utilized by control circuitry 80, can be programmed into memory 82 via telemetry circuitry 88, which can also be described as a communication interface. Telemetry circuitry 88 includes a transceiver and antenna for communicating with external devices such as programmers or home monitors using radio frequency communication or other communication protocols. Control circuitry 80 can use telemetry circuitry 88 to receive downlink telemetry from external devices and transmit uplink telemetry to external devices. In some cases, telemetry circuitry 88 can be used to transmit and receive communication signals to and from another medical device implanted in the patient.

[0085] The illustrative systems, methods, and apparatus described herein can be used or configured to determine whether the cardiac conduction system or other cardiac tissues (such as myocardial tissue) have been captured by VfA cardiac pacing therapy. Figure 7 The document describes an illustrative method 200 for determining cardiac conduction system capture. Typically, the illustrative method 200 can be described as being used to analyze electrical activity from internal or external cardiac tissue (e.g., from the patient's torso), to adjust VfA cardiac pacing therapy using various diagnostic pacing settings, and then to determine, based on the monitored electrical activity, whether VfA cardiac pacing therapy has captured (e.g., is pacing) the patient's cardiac conduction system. Furthermore, method 200 may be able to determine, based on the monitored electrical activity, whether the patient has AV blockage.

[0086] As shown, method 200 may include monitoring electrical activity 202. Electrical activity can be measured from outside the patient or from inside the patient. In other words, electrical activity can be measured from tissues outside the patient's body (e.g., skin) or from tissues inside the patient's body (e.g., heart tissue).

[0087] For example, method 200 may include using multiple external electrodes to monitor or measure electrical activity, such as regarding Figure 9-11 As shown and described. More specifically, for example, the plurality of external electrodes may be similar to the external electrodes provided by electrode device 110, as described herein. Figure 9-11 As described. In one embodiment, the plurality of external electrodes may be part of or incorporated into a vest or strap positioned around the patient's torso. More specifically, the plurality of electrodes may be described as surface electrodes positioned in an array, configured to be positioned near the skin of the patient's torso. It can be described that, when using multiple external electrodes, the monitoring process 202 can provide multiple electrocardiograms (ECGs), signals representing the depolarization and repolarization of the patient's heart, and / or multiple activation times.

[0088] Furthermore, for example, method 200 may include using one or more implanted electrodes to monitor or measure electrical activity, such as regarding Figure 1-6 As shown and described. In one or more embodiments, the implantable electrode may be positioned within one or more chambers of a patient's heart, such as one or more of the right atrium, left atrium, right ventricle, and left ventricle. In one or more embodiments, the implantable electrode may be positioned near cardiac tissue, such as one or more of the myocardium, endocardium, and pericardial spaces. Electrical activity may be provided as one or more electrograms (EGMs) or electrical signals of the patient's heart depolarization and repolarization.

[0089] VfA cardiac therapy can be delivered to the left ventricle using an AV delay or interval, which is the time interval between an atrial event (e.g., pacing depolarization or intrinsic depolarization) and left ventricular pacing. It should be understood that the terms AV delay and AV interval are used interchangeably in the description provided herein. In other words, AV interval is the same as AV delay, and vice versa.

[0090] Method 200 may further include providing an initial diagnostic AV interval 204. The diagnostic AV interval may be described as a selected or determined interval configured for use in the process described herein with respect to illustrative method 200 in order to determine whether VfA cardiac therapy has captured the cardiac conduction system and / or whether the patient has AV blockage.

[0091] The initial diagnostic AV interval may be shorter than the patient's intrinsic AV interval. The patient's intrinsic AV interval is the time interval between an atrial event (e.g., pacing depolarization or intrinsic depolarization) and intrinsic or spontaneous left ventricular depolarization. The initial diagnostic AV interval can be determined based on the patient's intrinsic AV interval. For example, the patient's intrinsic AV interval can be measured or sensed, and the initial diagnostic AV interval can then be generated or calculated based on the patient's intrinsic AV interval.

[0092] In one embodiment, the initial diagnostic AV interval can be a selected percentage of the patient's inherent AV interval. The selected percentage can be between about 50% and about 90% of the patient's inherent AV interval. In at least one embodiment, the selected percentage can be 70% of the patient's inherent AV interval. For example, if the patient's inherent AV delay is 150 milliseconds and the selected percentage is 70%, then the new modified diagnostic AV interval can be set to 105 milliseconds.

[0093] In another embodiment, the initial diagnostic AV interval can be a selected time period that is smaller than the patient's inherent AV interval. The selected time period can be approximately 20 milliseconds (ms) to approximately 50 milliseconds smaller than the patient's inherent AV interval. For example, if the patient's inherent AV delay is 160 milliseconds and the selected time period is 30 milliseconds, the new modified diagnostic AV interval could be set to 130 milliseconds for the inherent AV interval.

[0094] VfA pacing therapy 206 can be delivered using or based on the initial diagnostic AV interval. It should be understood that during or concurrent with the delivery of VfA pacing therapy 206, illustrative methods 200 may continue to monitor or collect electrical activity 202.

[0095] More specifically, the VfA pacing therapy 206 using an initial diagnostic AV interval or delay can be delivered by at least one electrode configured to electrically stimulate (e.g., depolarize, pace, etc.) the patient's left ventricle upon atrial sensing or after atrial pacing in left-ventricular pacing only, or upon atrial sensing or after atrial pacing in biventricular pacing. In some embodiments, the VfA pacing therapy using an initial diagnostic AV interval can be delivered over a therapy period of approximately 5 seconds to approximately 30 seconds. In some embodiments, the VfA pacing therapy using an initial diagnostic AV interval can be delivered for a therapy number of cardiac cycles between approximately 5 and approximately 30 cardiac cycles.

[0096] In at least one embodiment, each electrode in the electrode array may be coupled to one or more leads implanted in or near the patient's heart. Further, in at least one embodiment, the cardiac therapy 206 may be performed via, as described above... Figure 1-6 Leadless electrodes, as shown and described, are used for delivery. Although Figure 1-6 Such systems and devices are leadless; however, it should be understood that the illustrative systems, devices, and methods described herein can be used with any type of cardiac pacing system, including one lead, two leads, three leads, and more than three leads. Further, in at least one embodiment, the illustrative device can be implanted in the patient's right atrium, and one or more "leads" or short leads can extend from the device to another part or region of cardiac tissue, such as another chamber (e.g., the right ventricle), a different septum (e.g., the interatrial septum), etc. As described herein, while cardiac therapy delivery can be described as invasive, some of the illustrative systems, devices, and methods (such as those concerning...) Figure 9-11 The described (can be described as non-invasive).

[0097] Furthermore, one or more illustrative cardiac therapies may utilize a leaded or leadless implantable cardiac device comprising a tissue-piercing electrode implanted through the right atrial endocardium and central fibrous body from the Koch's triangle region of the right atrium to deliver cardiac therapy to or sense the electrical activity of the left ventricle in the basal and / or septal region of the left ventricular myocardium of the patient's heart, as described in U.S. Provisional Patent Application Serial No. 62 / 647,414, filed March 23, 2018, entitled "VfA Cardiac Therapy" and U.S. Provisional Patent Application Serial No. 62 / 725,763, filed August 31, 2018, entitled "Adaptive VfA Cardiac Therapy," each of which is incorporated herein by reference in its entirety.

[0098] The monitored electrical activity can be used to generate capture information 208 that can be further used to determine the capture of the cardiac conduction system by VfA cardiac therapy, and optionally to determine whether the patient has AV blockage. It can be described that capture of the cardiac conduction system, rather than capture of other cardiac tissues, means that the pacing electrode of VfA cardiac therapy, designed to at least depolarize the left ventricle, is delivering electrical pacing into rapid propagation of electrical activation, while exhibiting a low degree of transventricular electrical activation heterogeneity. The cardiac conduction system comprises specialized cellular networks including the left and right bundle branches, as well as a highly branched specialized Purkinje fiber network, which facilitates rapid propagation of electrical activation across the ventricles and results in highly synchronized cardiac action. The cardiac conduction system is part of the natural electrical conduction pathway descending to the ventricle through the AV junction. However, during activation in conventional ventricular pacing, electrical activation propagates from one cardiomyocyte to another (also known as “cell-to-cell”) and is slower and asynchronous, without the involvement of any specialized cardiac conduction system.

[0099] In one embodiment, the capture information 208 may include electrical heterogeneity information (EHI) generated from monitored electrical activity during VfA pacing therapy for the initial AV diagnostic interval and subsequent AV diagnostic intervals, as will be further described herein. EHI can be described as information or data representing at least one of mechanical cardiac function and electrical cardiac function. EHI and other cardiac therapy information can be described in U.S. Provisional Patent Application No. 61 / 834,133, filed June 12, 2013, entitled “Metrics of Electrical Dyssynchrony and Electrical Activation Patterns from Surface ECG Electrodes,” which is incorporated herein by reference in its entirety.

[0100] Electrical heterogeneity information (e.g., data) can be defined as information indicating at least one of mechanical or asynchronicity of the heart and / or electrical or asynchronicity of the heart. In other words, electrical heterogeneity information can represent a substitute for the actual mechanical and / or electrical function of a patient's heart. In at least one embodiment, relative changes in electrical heterogeneity information (e.g., from baseline heterogeneity information to therapeutic heterogeneity information, from a first set of heterogeneity information to a second set of therapeutic heterogeneity information, etc.) can be used to determine substitute values ​​representing changes in hemodynamic response (e.g., abrupt changes in LV pressure gradient). Left ventricular pressure can typically be invasively monitored using a pressure sensor located in the left ventricle of a patient's heart. Thus, using electrical heterogeneity information to determine substitute values ​​representing left ventricular pressure avoids the need for invasive monitoring using a left ventricular pressure sensor.

[0101] In at least one embodiment, the electrical heterogeneity information may include the standard deviation of ventricular activation time measured using some or all of the external electrodes, for example, as described herein regarding Figure 9-11 The described electrode device 110 has external electrodes. Further, local or regional electrical heterogeneity information may include the standard deviation and / or mean of activation times measured using electrodes located in certain anatomical regions of the trunk. For example, external electrodes on the left side of the patient's trunk may be used to calculate local or regional left-sided electrical heterogeneity information.

[0102] Electrical heterogeneity information can be generated using one or more different systems and / or methods. For example, electrical heterogeneity information can be generated using arrays or multiple surface electrodes and / or imaging systems as described below: U.S. Patent Application Publication No. 2012 / 0283587A1, published November 8, 2012, entitled "Assessing Intra-Cardiac Activation Patterns and Electrical Dyssynergy"; U.S. Patent Application Publication No. 2012 / 0284003A1, published November 8, 2012, entitled "Assessing Intra-Cardiac Activation Patterns"; and U.S. Patent No. 8,180,428B2, published May 15, 2012, entitled "Methods and Systems for Using in Selecting Cardiac Pacing Sites".

[0103] Electrical heterogeneity information may include one or more measures or metrics. For example, one measure or metric of electrical heterogeneity may be the standard deviation of activation time (SDAT) measured using some or all electrodes on the surface of a patient's torso. In some instances, SDAT may be calculated using estimated cardiac activation time on the surface of a model heart.

[0104] Another measure or indicator of electrical heterogeneity can be the left standard deviation of the surrogate electrical activation time (LVED) monitored by external electrodes located near the patient's left side. Further, another measure or indicator of electrical heterogeneity can include the average of the surrogate electrical activation time (LVAT) monitored by external electrodes located near the patient's left side. LVED and LVAT can be determined (e.g., calculated, estimated, etc.) based solely on electrical activity measured by electrodes located only near the patient's left side, which may be referred to as "left" electrodes. A left electrode can be defined as any surface electrode located near the left ventricle, which comprises the region on the left side of the patient's sternum and spine. In one embodiment, a left electrode may comprise all anterior electrodes on the left side of the sternum and all posterior electrodes on the left side of the spine. In another embodiment, a left electrode may comprise all anterior and all posterior electrodes on the left side of the sternum. In yet another embodiment, a left electrode may be designated based on the contours of the left and right sides of the heart determined using imaging equipment such as X-rays, fluoroscopy, etc.

[0105] Another illustrative measure or index of asynchrony can be the range of activation time (RAT), which can be calculated as the difference between the maximum and minimum activation times on the trunk surface or heart, for example, overall or for a region. RAT reflects the span of activation time, while SDAT gives an estimate of the deviation of activation time from the mean. SDAT also provides an estimate of the heterogeneity of activation time, because if activation time is spatially heterogeneous, individual activation times will be further away from the mean activation time, indicating activation delays in one or more regions of the heart. In some instances, RAT can be calculated using estimated cardiac activation times on the surface of a model heart.

[0106] Another illustrative measure or index of electrical heterogeneity information may include an estimate of the percentage of surface electrodes located in a specific region of interest in the trunk or heart whose relevant activation time is greater than a certain percentile (e.g., the 70th percentile) of the measured QRS complex duration or the determined activation time of the surface electrodes. The region of interest may be, for example, the posterior, left anterior, and / or left ventricular regions. An illustrative measure or index may be referred to as the percentage of delayed activation (PLAT). PLAT can be described as providing an estimate of the percentage of the region of interest, such as the posterior and left anterior regions associated with the left ventricular region of the heart, which activate later. A larger PLAT value may indicate delayed activation of a majority of the region (e.g., the left ventricle) and the potential benefit of electrical resynchronization via CRT through pre-excitation of the late region (e.g., the left ventricle). In other instances, PLAT may be determined for other subsets of electrodes in other regions, such as the right anterior region, to assess delayed activation in the right ventricle. In addition, in some instances, the estimated cardiac activation time on the surface of a model heart can be used to calculate PLAT for the entire heart or a specific region of the heart (e.g., the left or right ventricle).

[0107] In one or more embodiments, the electrical heterogeneity information may include indicators of favorable changes in overall cardiac electrical activation, as described in: Sweeney et al., “Analysis of Ventricular Activation Using Surface Electrocardiography to Predict Left Ventricular Reverse Volumetric Remodeling During Cardiac Resynchronization Therapy”, Circulation, 9 February 2010, 121(5):626-34 and / or Van Deursen et al., “Vectorcardiography as a Tool for Easy Optimization of Cardiac Resynchronization Therapy in Canine LBBB Hearts”, Circulation Arrhythmia and Electrophysiology, 1 June 2012, 5(3):544-52.Heterogeneity information may also include measurements of improved cardiac mechanical function, measured by imaging or other systems, to track the movement of implanted leads within the heart, as described in: Ryu et al., “Simultaneous Electrical and Mechanical Mapping Using 3D Cardiac Mapping System: Novel Approach for Optimal Cardiac Resynchronization Therapy”, Journal of Cardiovascular Electrophysiology, February 2010, 21(2):219-22; Sperzel et al., “Intraoperative Characterization of Interventricular Mechanical Dyssynchrony Using Electroanatomic Mapping System—A Feasibility Study”, Journal of Interventional Cardiac Electrophysiology, November 2012, 35(2):189-96 and / or entitled “METHOD FOR The patent application, titled "OPTIMIZAING CRT THERAPY", was published in U.S. Patent Application Publication No. 2009 / 0099619A1 on April 16, 2009.

[0108] In one embodiment, the captured information 208 may include one or more measures or metrics of electrocardiogram (EGM) signal data monitored or measured directly from cardiac tissue and / or one or more measures or metrics of electrocardiogram (ECG) signals monitored or measured indirectly from the patient's trunk. For example, QRS morphology, QRS duration, time interval between reference points on the ventricular EGM during depolarization (e.g., the timing difference between minimum and maximum amplitude), peak-to-peak amplitude, amplitude of slope or derivative, and combinations of two or more of these measures or characteristics from one or both of the EGM and ECG signals may be generated and recorded.

[0109] The illustrative method 200 may further include modifying or adjusting the AV diagnostic interval 210 after electrical activity has been monitored 202 during the delivery of VfA pacing therapy 206 with a previously diagnosed AV interval (which in the first iteration would be the initial diagnostic AV interval provided by process 204).

[0110] In one embodiment, the AV diagnostic interval 210 can be modified by reducing the AV diagnostic interval by a selected amount. For example, the selected amount can be between about 5 milliseconds and about 25 milliseconds. In one or more embodiments, the selected amount can be greater than or equal to about 5 milliseconds, greater than or equal to about 7 milliseconds, greater than or equal to about 10 milliseconds, greater than or equal to about 12 milliseconds, greater than or equal to about 15 milliseconds, etc., and / or less than or equal to about 30 milliseconds, less than or equal to about 25 milliseconds, less than or equal to about 20 milliseconds, less than or equal to about 17 milliseconds, etc. Therefore, if the previous diagnostic AV interval was 140 milliseconds and the selected amount was 20 milliseconds, the modified or adjusted AV diagnostic interval would be 120 milliseconds.

[0111] In one embodiment, the AV diagnostic interval 210 can be modified by reducing the AV diagnostic interval by a selected percentage. For example, the selected percentage can be between about 2% milliseconds and about 20% milliseconds. In one or more embodiments, the selected percentage can be greater than or equal to about 2%, greater than or equal to about 5%, greater than or equal to about 7%, etc., and / or less than or equal to about 15%, less than or equal to about 12%, less than or equal to about 10%, etc. Therefore, if the previous diagnostic AV interval was 150 milliseconds and the selected percentage was 10%, the modified or adjusted AV diagnostic interval would be 135 milliseconds.

[0112] Method 200 may then check whether the modified diagnostic AV interval is less than a minimum value 212. The minimum value 212 may be between approximately 40 milliseconds and approximately 70 milliseconds. In one embodiment, the minimum value 212 is 60 milliseconds. If the modified diagnostic AV interval is less than the minimum value 212, method 200 may proceed to determine whether VfA pacing therapy has captured the cardiac conduction system 214 and / or determine whether the patient has AV blockage 216, as will be further described herein.

[0113] If the modified diagnostic AV interval is not less than the minimum value 212, then method 200 can return to delivering VfA pacing therapy 206 according to the modified diagnostic AV interval, during which capture information 208 is generated using monitored electrical activity 202, and then the diagnostic AV interval 210 is modified. Method 200 can continue in this loop until the modified diagnostic AV interval is less than the minimum value 212.

[0114] Therefore, method 200 can be described as modifying the diagnostic AV interval 210 into a plurality of distinct diagnostic AV intervals, each smaller than the patient's inherent AV interval, and monitoring electrical activity 202 during each diagnostic AV delay within the plurality of distinct diagnostic AV intervals, which can then be used to generate capture information 208. When the diagnostic AV interval is modified or reduced to be equal to or below a minimum value 212, method 200 can stop or discontinue the delivery of VfA pacing therapy using the diagnostic AV interval. In other words, the diagnostic AV interval can be described as being "sweeped" from an initial diagnostic AV interval to a minimum diagnostic AV interval, and capture data can be collected during the "sweep".

[0115] Method 200 may then utilize one or both of the monitored electrical activity 202 measured during the plurality of different diagnostic AV intervals and the capture information 208 generated based on such monitored electrical activity to determine whether VfA pacing therapy has captured the cardiac conduction system 214 and / or to determine whether the patient has AV blockage 216, as will be further described herein.

[0116] Various procedures and acquisition information can be used to determine whether VfA pacing therapy has captured the cardiac conduction system 214. For example, acquisition information containing asynchronous information such as EHI can be utilized. Figures 8A-8C The figure depicts the asynchronous decrease in diagnostic AV interval, illustrating various scenarios of cardiac conduction capture, no cardiac conduction capture, and AV blockage.

[0117] Figure 8A Two distinct sets of asynchronous information are depicted. The first set of asynchronous information 220 indicates successful capture of the cardiac conduction system, while the second set of asynchronous information 222 indicates no or unsuccessful capture. As shown in 8A, as the diagnostic AV interval decreases (i.e., shifts to the right along the X-axis), the first set of asynchronous information 220 indicating successful cardiac conduction system capture neither increases nor decreases—instead, the first set of asynchronous information 220 remains relatively constant, for example, within a predefined tolerance (e.g., + / -5%, + / -10%, + / -3 ms, + / -5 ms, etc.). The lack of change in asynchronous information as the diagnostic AV interval decreases may indicate successful cardiac conduction system capture.

[0118] Conversely, as the diagnostic AV interval decreases, the second set of asynchronous information 222, indicating failure or unsuccessful capture of the cardiac conduction system, decreases and then subsequently increases. In short, the second set of asynchronous information 222 changes over time. The change in asynchronous information as the diagnostic AV interval decreases can indicate unsuccessful or incomplete capture of the cardiac conduction system.

[0119] Therefore, changes in asynchrony can be identified during pacing with a shorter AV interval by increasing electrical heterogeneity or dyssynchrony without capturing the conduction system, since the entire activation of the heart occurs via cell-to-cell propagation, which is much slower. In some cases, when there is a considerable local tissue delay (e.g., measured by the interval between pacing delivery and QRS initiation), changes in asynchrony can be identified by reducing electrical dyssynchrony during pacing with a shorter AV interval without capturing the conduction system.

[0120] Therefore, if asynchronous information such as EHI changes as the diagnostic AV interval decreases, then illustrative method 200 can determine that VfA pacing therapy has not captured the cardiac conduction system 214. Furthermore, and similarly, if asynchronous information such as EHI remains relatively constant as the diagnostic AV interval decreases, then illustrative method 200 can determine that VfA pacing therapy has captured the cardiac conduction system 214.

[0121] exist Figure 8B The diagram depicts two distinct sets of asynchronous information, with both the first set 220 and the second set 224 indicating successful capture of the cardiac conduction system, because, for example, the asynchronous information does not increase or decrease, and the two sets 220 and 224 remain relatively constant, etc. However, the second set of asynchronous information 224 is above a threshold 230, which can indicate AV blockage. If the asynchronous measure used is the standard deviation of activation time (SDAT), the threshold can be between approximately 20 ms and 25 ms.

[0122] Therefore, if the asynchronous information remains relatively constant and is above a selected threshold over multiple different diagnostic AV intervals (e.g., as the diagnostic AV interval decreases), the illustrative method 200 can determine that the patient has AV blockage.

[0123] Figure 8C Two distinct sets of asynchronous information are depicted. The first set of asynchronous information 220 indicates successful capture of the cardiac conduction system, while the second set of asynchronous information 226 indicates no or unsuccessful capture. As shown in 8C, as the diagnostic AV interval decreases (i.e., shifts to the right along the X-axis), the first set of asynchronous information 220, indicating successful capture of the cardiac conduction system, neither increases nor decreases—instead, the first set of asynchronous information 220 remains relatively constant. As previously stated, no change in asynchronous information as the diagnostic AV interval decreases may indicate successful capture of the cardiac conduction system.

[0124] Conversely, as the diagnostic AV interval decreases, a second set of asynchronous information 226, indicating failure or unsuccessful capture of the cardiac conduction system, steadily increases. In short, the second set of asynchronous information 226 changes over time. Changes in asynchronous information as the diagnostic AV interval decreases can indicate unsuccessful or incomplete capture of the cardiac conduction system.

[0125] Various procedures for analyzing and evaluating EGM, ECG signals, and / or portions thereof can be used to determine whether VfA pacing therapy has captured the cardiac conduction system 214. For example, capture information may include the QRS segment in the EGM and / or ECG signals following a ventricular pacing event. One or both of the morphology and duration can be compared across the multiple different diagnostic AV intervals to determine whether VfA pacing therapy has successfully captured the cardiac conduction system.

[0126] In one embodiment, the morphological template of a QRS segment following a ventricular pacing event, from the delivery time of pacing to a predefined time interval (e.g., 250 milliseconds after atrial pacing delivery), can be stored during pacing at a diagnostic AV interval (e.g., a short AV delay, such as 60 milliseconds). The morphological similarity of QRS segments during pacing at other diagnostic AV intervals (e.g., longer diagnostic AV intervals, such as 80 milliseconds, 100 milliseconds, 120 milliseconds, etc.) can be determined based on a simple correlation of QRS segments within the same time window following pacing delivery. Morphological similarity can be determined if the correlation coefficient exceeds a certain threshold (e.g., 90%). Other measures, such as relative difference, can also be used to determine the similarity of electrogram morphology or other characteristics. If the relative difference is less than a certain threshold (e.g., 5%, 10%, etc.), a match or similarity of characteristics is determined. If the QRS signal segment during a short AV pacing interval is similar to that during a longer AV pacing interval (e.g., closely matched, within tolerance levels, etc.) (e.g., in terms of one or both of the QRS morphology and duration), then VfA pacing therapy can be determined to have successfully captured one or both of the left and right ventricles. Conversely, if the QRS signal segment during a short AV pacing interval differs from that during a longer AV pacing interval (e.g., in terms of one or both of the QRS morphology and duration), then VfA pacing therapy can be determined to have failed to capture one or both of the left and right ventricles.

[0127] As described herein, one of the various methods or processes for monitoring electrical activity during the multiple different diagnostic AV delays and subsequently generating capture information therefrom utilizes multiple electrocardiogram (ECG) signals (e.g., trunk surface potentials). These multiple ECG signals can be measured or monitored using multiple external electrodes positioned on or around the patient's surface or skin. The ECG signals can be used to determine capture of the cardiac conduction system by VfA therapy, for example, provided by an implantable medical device performing VfA cardiac resynchronization therapy (CRT). As described herein, because, for example, implantable electrodes may not be used to measure ECG signals, the ECG signals can be collected or obtained non-invasively. Furthermore, the ECG signals can be used to determine cardiac electrical activation time, which can be used to generate various metrics (e.g., electrical heterogeneity information) that can be used to determine capture of the cardiac conduction system.

[0128] Various illustrative systems, methods, and graphical user interfaces can be configured to noninvasively assist users (e.g., physicians) in assessing cardiac conduction system capture and / or the configuration (e.g., optimization) of cardiac therapies using electrode devices, display devices, and computing devices that include external electrodes. Figure 9 The illustration depicts a system 100 including an electrode device 110, a computing device 140, and a remote computing device 160.

[0129] The electrode device 110 shown includes a plurality of electrodes incorporated or contained within a band wrapped around the chest or torso of a patient 114. The electrode device 110 is operatively coupled to a computing device 140 (e.g., via a wired or wireless connection) to provide electrical signals from each of the electrodes to the computing device 140 for analysis, evaluation, etc. An illustrative electrode device can be described in U.S. Patent No. 9,320,446, filed March 27, 2014, and published March 26, 2016, entitled “Bioelectric Sensor Device and Methods.” Further reference will be made to… Figure 2-3 A more detailed description of the illustrative electrode device 110 is provided.

[0130] Computing device 140 and remote computing device 160 may each include display devices 130 and 160, respectively, which can be configured to display and analyze data, such as electrical signals (e.g., electrocardiogram data), electrical activation time, electrical heterogeneity information, etc. For example, one or more measures of a cardiac cycle or a single heartbeat represented by electrical signals collected or monitored by electrode device 110 can be analyzed and evaluated, the one or more measures including activation time and electrical heterogeneity information that can be related to the determination of cardiac conduction system capture and the detection of AV blockage. More specifically, for example, one or more measures of the QRS complex in a single cardiac cycle can be assessed, such as QRS onset, QRS deviation, QRS peak, electrical heterogeneity information (EHI), electrical activation time, standard deviation of left ventricular or thoracic electrical activation time (LVED), standard deviation of activation time (SDAT), mean left ventricular or thoracic substitution electrical activation time (LVAT), reference earliest activation time, QRS duration (e.g., the interval between QRS onset and QRS deviation), difference between mean left substitution and mean right substitution activation times, relative or absolute QRS morphology, difference between higher and lower percentiles of activation time (higher percentiles may be 90%, 80%, 75%, 70%, etc. and lower percentiles may be 10%, 15%, 20%, 25%, and 30%, etc.), other statistical measures of central tendency (e.g., median or mode), deviations (e.g., mean deviation, standard deviation, variance, interquartile range), etc. Furthermore, each of the one or more measures can be location-specific. For example, some metrics can be calculated based on signals recorded or monitored from electrodes positioned around selected areas of the patient (e.g., the patient's left side, the patient's right side, etc.).

[0131] In at least one embodiment, one or both of the computing device 140 and the remote computing device 160 may be a server, a personal computer, or a tablet computer. The computing device 140 may be configured to receive input from an input device 142 (e.g., a keyboard) and transmit output to a display device 130, and the remote computing device 160 may be configured to receive input from an input device 162 (e.g., a touchscreen) and transmit output to a display device 170. One or both of the computing device 140 and the remote computing device 160 may include a data storage device that allows access to processing programs or routines and / or one or more other types of data, such as for analyzing multiple electrical signals captured by the electrode device 110, for determining QRS start, QRS offset, median, mode, average, peak or maximum, trough or minimum, for determining electrical activation time, for determining whether VfA pacing therapy has captured the cardiac conduction system, for determining whether the patient has AV blockage, and for driving a graphical user interface configured to noninvasively assist the user in configuring one or more pacing parameters or settings, such as pacing rate, ventricular pacing rate, AV interval, VV interval, pacing pulse width, pacing vector, multi-point pacing vector (e.g., left ventricular vector four-lead), pacing voltage, pacing configuration (e.g., biventricular pacing, right ventricular pacing only, left ventricular pacing only, etc.), as well as arrhythmia detection and treatment, rate adaptive settings, and performance, etc.

[0132] Computing device 140 can be operatively coupled to input device 142 and display device 130 to transmit data to and from each of the input devices 142 and 130, for example, and remote computing device 160 can be operatively coupled to input device 162 and display device 170 to transmit data to and from each of the input devices 162 and 170, for example,. For example, computing device 140 and remote computing device 160 can be electrically coupled to input devices 142, 162 and display devices 130, 170 using analog electrical connections, digital electrical connections, wireless connections, bus-based connections, network-based connections, Internet-based connections, etc. As further described herein, a user can provide input to input devices 142, 162 to view and / or select one or more cardiac conduction system capture information, AV blocking information, and configuration information related to cardiac therapy delivered by a cardiac therapy device (e.g., an implantable medical device).

[0133] Although, as depicted, input device 142 is a keyboard and input device 162 is a touchscreen, it should be understood that input devices 142 and 162 may include any device capable of providing input to computing device 140 and computing device 160 to perform the functions, methods, and / or logic described herein. For example, input devices 142 and 162 may include a keyboard, mouse, trackball, touchscreen (e.g., capacitive touchscreen, resistive touchscreen, multi-touch touchscreen, etc.), etc. Similarly, display devices 130 and 170 may include any device capable of displaying information to the user, such as graphical user interfaces 132 and 172, including electrode status information, graphical representations of electrical activation, multiple signals from external electrodes on one or more heartbeats, QRS complex waves, selection areas for various cardiac therapy options, rankings of various cardiac therapy options, various pacing parameters, electrical heterogeneity information (EHI), text commands, graphical depictions of the anatomical structure of the human heart, images or graphical depictions of the patient's heart, graphical depictions of the locations of one or more electrodes, graphical depictions of the human torso, images or graphical depictions of the patient's torso, graphical depictions or actual images of implanted electrodes and / or leads, etc. Furthermore, display devices 130 and 170 may include liquid crystal displays, organic light-emitting diode screens, touch screens, cathode ray tube displays, etc.

[0134] The processing programs or routines stored and / or executed by the computing device 140 and the remote computing device 160 may include programs or routines for computational mathematics, matrix mathematics, decomposition algorithms, compression algorithms (e.g., data compression algorithms), calibration algorithms, image construction algorithms, signal processing algorithms (e.g., various filtering algorithms, Fourier transform, fast Fourier transform, etc.), normalization algorithms, comparison algorithms, vector mathematics, or any other processing that implements one or more of the illustrative methods and / or processes described herein. The data stored and / or used by the computing device 140 and the remote computing device 160 may include, for example, electrical signal / waveform data (e.g., multiple QRS complex waves) from the electrode device 110, electrical activation time from the electrode device 110, heart sound / signal / waveform data from the acoustic sensor, graphics (e.g., graphic elements, icons, buttons, windows, dialog boxes, drop-down menus, graphics areas, graphics regions, 3D graphics, etc.), graphical user interfaces, results of one or more processing procedures or routines adopted according to this disclosure (e.g., electrical signals, electrical heterogeneity information, etc.), or any other data used to perform one or more processes or methods described herein.

[0135] In one or more embodiments, the illustrative systems, methods, and interfaces may be implemented using one or more computer programs that execute on a programmable computer (e.g., a computer including, for example, processing power, data storage devices (e.g., volatile or non-volatile memory and / or storage elements), input devices, and output devices). The program code and / or logic described herein may be applied to input data to perform the functions described herein and produce desired output information. The output information may be applied as input to one or more other means and / or methods described herein or to be applied in a known manner.

[0136] Any programmable language can be used to provide one or more programs for implementing the systems, methods, and / or interfaces described herein, such as high-level programs and / or object-oriented programming languages ​​suitable for communicating with computer systems. For example, any such program can be stored on any suitable means, such as a storage medium, readable by a general or special program that runs on a computer system (e.g., containing a processing device) to configure and operate the computer system to perform the programs described herein when read by a suitable device. In other words, at least in one embodiment, the illustrative systems, methods, and interfaces can be implemented using a computer-readable storage medium configured with computer programs, wherein such a storage medium causes a computer to operate in a specific and predefined manner to perform the functions described herein. Further, in at least one embodiment, the illustrative systems, methods, and / or interfaces can be described as being implemented by logic (e.g., object code) encoded in one or more non-transitory media, the logic containing code for execution and operable, when executed by a processor or processing circuitry system, to perform operations such as the methods, processes, and / or functions described herein.

[0137] Computing device 140 and remote computing device 160 can be, for example, any fixed or mobile computer system (e.g., controller, microcontroller, personal computer, microcomputer, tablet computer, etc.). The exact configuration of computing device 140 and remote computing device 160 is not limiting, and any device capable of providing suitable computing and control capabilities (e.g., signal analysis, mathematical functions such as median, mode, average, maximum value determination, minimum value determination, slope determination, minimum slope determination, maximum slope determination, graphics processing, etc.) can be used. As described herein, digital files can be any medium (e.g., volatile or non-volatile memory, CD-ROM, punched card, magnetically recordable magnetic tape, etc.) containing digital bits (e.g., encoded in binary or ternary) that can be read and / or written by computing device 140 and remote computing device 160 as described herein. Moreover, as described herein, a user-readable format file can be any representation of data (e.g., ASCII text, binary numbers, hexadecimal numbers, decimal numbers, graphics, etc.) that can be presented on any medium (e.g., paper, monitor, etc.) that can be read and / or understood by a user.

[0138] In view of the foregoing, it will be apparent that the functions described in one or more embodiments of this disclosure can be implemented in any manner known to those skilled in the art. Thus, the computer language, computer system, or any other software / hardware to be used to implement the processes described herein should not limit the scope of the systems, processes, or programs described herein (e.g., the functionality provided by such systems, processes, or programs).

[0139] The illustrative electrode device 110 can be configured to measure the body surface potential of the patient 114, and more specifically, to measure the trunk surface potential of the patient 114. For example... Figure 2 As shown, the illustrative electrode device 110 may include a group or array of external electrodes 112, a strip 113, and an interface / amplifier circuitry system 116. Electrodes 112 may be attached to or coupled to the strip 113, and the strip 113 may be configured to wrap around the torso of the patient 114 such that the electrodes 112 surround the patient's heart. As further shown, the electrodes 112 may be positioned around the patient 114, including posterior, lateral, posterolateral, anterior, and anterior locations of the patient 114's torso.

[0140] The illustrative electrode device 110 can be further configured to measure or monitor sounds from at least one or both patients 114. For example... Figure 2As shown, the illustrative electrode device 110 may include a group or array of acoustic sensors 120 attached to or coupled to the strip 113. The strip 113 may be configured to wrap around the torso of the patient 114 such that the acoustic sensors 120 surround the patient's heart. As further shown, the acoustic sensors 120 may be positioned around the patient 114, including posterior, lateral, rear, anterior, and frontal locations of the patient 114's torso.

[0141] Furthermore, electrode 112 and acoustic sensor 120 can be electrically connected to interface / amplifier circuitry 116 via wired connection 118. Interface / amplifier circuitry 116 can be configured to amplify signals from electrode 112 and acoustic sensor 120 and provide the signals to one or both of computing device 140 and remote computing device 160. Other illustrative systems may use wireless connections (e.g., as data channels) to transmit signals sensed by electrode 112 and acoustic sensor 120 to interface / amplifier circuitry 116, and further to one or both of computing device 140 and remote computing device 160. In one or more embodiments, interface / amplifier circuitry 116 can be electrically coupled to computing device 140 using, for example, analog electrical connections, digital electrical connections, wireless connections, bus-based connections, network-based connections, Internet-based connections, etc.

[0142] Despite Figure 2In one example, electrode device 110 includes a strip 113, but in other examples, any of a variety of mechanisms, such as tape or adhesive, can be used to assist in the spacing and placement of electrodes 112 and acoustic sensors 120. In some examples, strip 113 may comprise elastic bands, tape strips, or cloth. Further, in some examples, strip 113 may be part of or integrated with a garment (e.g., a T-shirt). In other examples, electrodes 112 and acoustic sensors 120 may be placed separately on the torso of patient 114. Further, in other examples, one or both of electrodes 112 (e.g., arranged in an array) and acoustic sensors 120 (e.g., also arranged in an array) may be patches, vests, and / or other means of securing electrodes 112 and acoustic sensors 120 to or within the torso of patient 114. Furthermore, in other embodiments, one or both of the electrodes 112 and the acoustic sensors 120 may be two portions of material or part of two patches or positioned therein. One of the two patches may be positioned on the front side of the patient 114's torso (e.g., to monitor electrical signals representing the front side of the patient's heart, measure the electrical activation time of an alternative heart representing the front side of the patient's heart, monitor or measure sound on the front side of the patient, etc.) and the other patch may be positioned on the rear side of the patient 114's torso (e.g., to monitor electrical signals representing the rear side of the patient's heart, measure the electrical activation time of an alternative heart representing the rear side of the patient's heart, monitor or measure sound on the rear side of the patient, etc.). And further still, in other embodiments, one or both of the electrodes 112 and the acoustic sensors 120 may be arranged to extend from the front side of the patient 114 across the left side of the patient 114 to the top and bottom rows of the front side of the patient 114. Furthermore, in other instances, one or both of the electrodes 112 and acoustic sensors 120 may be arranged in a curve around the axillary region, and the electrode / sensor density on the right chest may be lower than that in the other remaining areas.

[0143] Electrodes 112 can be configured to surround the heart of patient 114 and record or monitor electrical signals associated with cardiac depolarization and repolarization after a signal has propagated through the torso of patient 114. Each electrode in 112 can be used in a monopolar configuration to sense torso surface potentials reflecting cardiac signals. Interface / amplifier circuitry 116 can also be coupled to a return electrode or an unrelated electrode (not shown) that can be used in combination with each electrode 112 for monopolar sensing.

[0144] In some instances, there may be approximately 12 to approximately 50 electrodes 112 spatially distributed around the patient's torso, and approximately 12 to approximately 50 acoustic sensors 120. Other configurations may have more or fewer electrodes 112 and more or fewer acoustic sensors 120. It should be understood that the electrodes 112 and acoustic sensors 120 may not be arranged or distributed in an array extending all around or completely around the patient 114. Alternatively, the electrodes 112 and acoustic sensors 120 may be arranged in an array that extends around only a portion or part of the patient 114. For example, the electrodes 112 and acoustic sensors 120 may be distributed on the front, back, and left sides of the patient, with fewer or no electrodes and acoustic sensors on the right side (including the posterior and anterior regions of the patient's right side).

[0145] The computing device 140 can record and analyze trunk surface potential signals sensed by electrode 112 and sound signals sensed by acoustic sensor 120, which are amplified / modulated by interface / amplifier circuitry system 116. The computing device 140 can be configured to analyze electrical signals from electrode 112 to provide electrocardiogram (ECG) signals, information, or data from the patient's heart, as will be further described herein. The computing device 140 can also be configured to analyze electrical signals from acoustic sensor 120 to provide sound signals, information, or data from the patient's body and / or implanted devices (such as left ventricular assist devices).

[0146] Additionally, computing device 140 and telecomputing device 160 can be configured to provide graphical user interfaces 132 and 172 that depict various information associated with electrode device 110 and data collected or sensed using electrode device 110. For example, graphical user interfaces 132 and 172 can depict ECG data including QRS complexes obtained using electrode device 110 and acoustic data including sound waves obtained using acoustic sensor 120, along with other related information. The illustrative system and method can noninvasively use electrical information collected using electrode device 110 and acoustic information collected using acoustic sensor 120 to assess a patient's cardiac health and evaluate and configure cardiac therapies delivered to the patient.

[0147] Furthermore, the electrode device 110 may further include reference electrodes and / or drive electrodes, for example, said reference electrodes and / or drive electrodes to be positioned around the lower torso of the patient 114, which may be further used by the system 100. For example, the electrode device 110 may include three reference electrodes, and signals from the three reference electrodes may be combined to provide a reference signal. Furthermore, the electrode device 110 may use three tail reference electrodes (e.g., instead of the standard reference used in the Wilson central terminal) to obtain a “true” unipolar signal with less noise by averaging the three tail-positioned reference signals.

[0148] Figure 3 Another illustrative electrode device 110 is shown, comprising a plurality of electrodes 112 and a plurality of acoustic sensors 120. The electrodes are configured to surround the heart of a patient 114 and record or monitor electrical signals associated with cardiac depolarization and repolarization after the signal has propagated through the torso of the patient 114. The acoustic sensors are configured to surround the heart of the patient 114 and record or monitor cardiac-related sound signals after the signal has propagated through the torso of the patient 114. The electrode device 110 may include a vest 114 to which the plurality of electrodes 112 and the plurality of acoustic sensors 120 may be attached or coupled. In at least one embodiment, the plurality of electrodes 112 or an array of the electrodes may be used to collect electrical information, such as alternative electrical activation time. Figure 2 The electrode device 110 is similar. Figure 3 The electrode device 110 may include an interface / amplifier circuitry 116 electrically coupled to each of the electrodes 112 and acoustic sensors 120 via a wired connection 118 and configured to transmit signals from the electrodes 112 and acoustic sensors 120 to a computing device 140. As shown, the electrodes 112 and acoustic sensors 120 may be distributed on the torso of the patient 114, including, for example, the posterior surface, lateral surface, posterolateral surface, anterior surface, and anterior position of the torso of the patient 114.

[0149] Vest 114 may be formed of fabric, with electrodes 112 and acoustic sensors 120 attached to the fabric. Vest 114 may be configured to maintain the positioning and spacing of electrodes 112 and acoustic sensors 120 on the torso of patient 114. Further, vest 114 may be marked to aid in determining the position of electrodes 112 and acoustic sensors 120 on the surface of the torso of patient 114. In some instances, although approximately 25 to approximately 256 electrodes 112 and approximately 25 to approximately 256 acoustic sensors 120 may be distributed around the torso of patient 114, other configurations may have more or fewer electrodes 112 and more or fewer acoustic sensors 120.

[0150] Illustrative systems and methods can be used to provide noninvasive assistance to users in assessing a patient's cardiac health and / or evaluating and configuring cardiac therapies currently delivered to the patient (e.g., via implantable medical devices such as VfA pacing devices, via LVADs, etc.). For example, illustrative systems and methods can be used to assist a user in determining whether one or more electrodes have successfully captured one or both ventricles for VfA pacing therapy and whether the patient is experiencing AV blockage. Further, for example, illustrative systems and methods can be used to assist a user in configuring and / or adjusting one or more cardiac therapy settings, such as optimizing the AV interval or delay of pacing therapies (e.g., left ventricular only or left univentricular pacing therapy) and the AV interval or delay and VV interval or delay of pacing therapies (e.g., biventricular pacing therapy).

[0151] Furthermore, it should be understood that computing device 140 and remote computing device 160 can be operatively coupled to each other in a variety of different ways to perform or execute the functions described herein. For example, in the depicted embodiment, computing device 140 can be operatively wirelessly coupled to remote computing device 160, as depicted by the wireless signal lines emitted therebetween. Alternatively, in contrast to a wireless connection, one or more of computing device 140 and remote computing device 160 can be operatively coupled via one or a wired electrical connection.

[0152] The technologies described in this disclosure, including those belonging to IMD 10, device 50, IMD 310, computing device 140, and computing device 160 and / or various constituent components, can be implemented at least in part in hardware, software, firmware, or any combination thereof. For example, aspects of these technologies can be implemented within one or more processors (including one or more microprocessors, DSPs, ASICs, FPGAs, or any other equivalent integrated or discrete logic circuit systems, and any combination of such components), embodied in a programmer, such as a physician or patient programmer, stimulator, image processing device, or other device. The terms “module,” “processor,” or “processing circuit system” can generally refer to any circuit system, alone or in combination with other logic circuit systems, or any other equivalent circuit system.

[0153] Such hardware, software, and / or firmware may be implemented within the same device or in separate devices to support the various operations and functions described in this disclosure. Furthermore, any described unit, module, or component may be implemented together or individually as discrete but interoperable logical devices. Describing different features as modules or units is intended to highlight different functional aspects and does not necessarily imply that such modules or units must be implemented by separate hardware or software components. Rather, the functionality associated with one or more modules or units may be performed by separate hardware or software components, or integrated into shared or separate hardware or software components.

[0154] When implemented in software, the functionality attributable to the systems, apparatus, and techniques described herein can be embodied in instructions on a computer-readable medium such as RAM, ROM, NVRAM, EEPROM, flash memory, magnetic data storage media, optical data storage media, etc. The instructions can be executed by a processing circuit system and / or one or more processors to support one or more aspects of the functionality described herein.

[0155] All references and publications cited herein are expressly incorporated in their entirety for all purposes, unless any incorporated reference directly contradicts this disclosure.

[0156] Unless otherwise specified, all scientific and technical terms used herein have the meaning generally understood 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.

[0157] Unless otherwise stated, all figures used in the specification and claims that indicate feature dimensions, quantities, and physical properties are to be understood as being modified by the terms “completely” or “about”. Therefore, unless indicated to the contrary, the numerical parameters shown in the foregoing specification and appended claims are approximations that may vary depending on the skill of a person skilled in the art utilizing the teachings disclosed herein or, for example, seeking to obtain the desired properties within typical ranges of experimental error.

[0158] The numerical ranges listed by endpoints include all numbers included within the range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5) and any range within the range. In this document, the terms "at most" or "not greater than" a number (e.g., at most 50) include that number (e.g., 50), and the terms "not less than" a number (e.g., not less than 5) include that number (e.g., 5).

[0159] The terms “coupled” or “connected” refer to components being directly connected to each other (in direct contact with each other) or indirectly connected (having one or more components between two components and connecting them). Both terms can be modified by “operationally” and “operably”, and they can be used interchangeably to describe a coupling or connection configured to allow components to interact to perform at least some functions (e.g., a first medical device can be operably coupled to another medical device to send or receive information in the form of data).

[0160] Orientation-related terms, such as “top,” “bottom,” “side,” and “end,” are used to describe the relative position of components and do not imply limitation on the orientation of the embodiments under consideration. For example, embodiments described as having a “top” and a “bottom” also include embodiments in which they rotate in various directions, unless otherwise clearly indicated by the content.

[0161] The references to "one embodiment," "an embodiment," "certain embodiments," or "some embodiments," etc., mean that a particular feature, configuration, composition, or characteristic described in connection with the embodiment is included in at least one embodiment of this disclosure. Therefore, the appearance of these phrases in various places does not necessarily refer to the same embodiment of this disclosure. Furthermore, in one or more embodiments, particular features, configurations, compositions, or characteristics may be combined in any suitable manner.

[0162] As used in this specification and the appended claims, unless otherwise expressly stated herein, the singular forms “a,” “an,” and “the” include embodiments having multiple referents. Unless otherwise expressly stated herein, as used in this specification and the appended claims, the term “or” is generally used in its sense to include “and / or.”

[0163] As used in this article, words such as “have,” “possess,” “include,” and “contain” are used in their open-ended sense and generally refer to “including but not limited to.” It will be understood that phrases such as “consistent with…” and “comprises from…” are included within words such as “contains.”

[0164] The term "and / or" refers to one or all of the listed elements or a combination of at least two of the listed elements. The phrases "at least one," "including at least one," and "one or more" that follow the list refer to any item in the list and any combination of two or more items in the list.

[0165] Illustrative Examples

[0166] Example 1: A system comprising:

[0167] a. An electrode device comprising a plurality of electrodes for monitoring electrical activity from a patient's tissues; and

[0168] b. A computing device, the computing device including a processing circuit system, coupled to the electrode device and configured to:

[0169] i. Monitoring the patient's cardiac electrical activity using one or more of the plurality of electrodes during atrioventricular (VfA) pacing therapy with multiple diagnostic AV delays, wherein each of the plurality of diagnostic AV delays is less than the patient's inherent AV delay; and

[0170] ii. Determine whether the VfA pacing therapy has captured the cardiac conduction system based on the electrical activity monitored during the multiple diagnostic AV delayed delivery VfA pacing therapies.

[0171] Example 2: A method comprising:

[0172] a. Monitoring the patient's cardiac electrical activity using one or more of a plurality of electrodes during atrioventricular (VfA) pacing therapy with multiple diagnostic AV delays, wherein each of the plurality of diagnostic AV delays is less than the patient's inherent AV delay; and

[0173] b. Determine whether the VfA pacing therapy has captured the cardiac conduction system based on the electrical activity monitored during the multiple diagnostic AV delayed delivery VfA pacing therapies.

[0174] Example 3: An implantable medical device comprising:

[0175] a. A plurality of electrodes, said plurality of electrodes comprising:

[0176] i. A right atrial electrode, which can be positioned within the right atrium to deliver cardiac therapy to the right atrium of the patient's heart or to sense the electrical activity of the right atrium, and

[0177] ii. A tissue-penetrating electrode that can be implanted through the right atrial endocardium and central fibrous body to deliver cardiac therapy to the left ventricle of a patient's heart or to sense the electrical activity of the left ventricle;

[0178] b. A therapy delivery circuit, operatively coupled to the plurality of electrodes to deliver cardiac therapy to the patient's heart;

[0179] c. A sensing circuit operatively coupled to the plurality of electrodes to sense the electrical activity of the patient's heart; and

[0180] d. A controller comprising a processing circuitry system operatively coupled to the therapy delivery circuitry and the sensing circuitry, the controller being configured to:

[0181] i. At least the tissue puncture electrode is used to deliver atrial to ventricular (VfA) pacing therapy with multiple diagnostic AV delays, wherein each of the multiple diagnostic AV delays is less than the patient's inherent AV delay;

[0182] ii. Monitoring the patient's cardiac electrical activity using one or more of the plurality of electrodes during the plurality of diagnostic AV delayed delivery VfA pacing therapies; and

[0183] iii. Determine whether the VfA pacing therapy has captured the cardiac conduction system based on the electrical activity monitored during the multiple diagnostic AV delayed delivery VfA pacing therapies.

[0184] Example 4: A system, method, or apparatus according to any one of Examples 1 to 3, wherein the system further comprises a VfA pacing therapy device, wherein the VfA pacing therapy device comprises a tissue puncture electrode that can be implanted through the right atrial endocardium and central fibrous body from the Koch's triangle region of the right atrium to deliver the VfA pacing therapy to the left ventricle in the base and / or septum of the left ventricular myocardium of the patient's heart.

[0185] Example 5: The system, method, or apparatus according to any one of Examples 1 to 4, wherein the longest of the plurality of diagnostic AV delays is less than or equal to 70% of the patient’s inherent AV delay.

[0186] Example 6: A system or method according to any one of Examples 1 to 2 and 4 to 5, wherein the plurality of electrodes comprises a plurality of surface electrodes positioned in an array, the plurality of surface electrodes being configured to be positioned near the skin of the patient's torso.

[0187] Example 7: A system, method, or apparatus according to any one of Examples 1 to 2 and 4 to 6, wherein the computing device is further configured to perform, or the method further comprises: generating electrical heterogeneity information (EHI) based on the monitored electrical activity during the plurality of diagnostic AV delayed delivery VfA pacing therapies, wherein determining whether the VfA pacing therapy has captured the cardiac conduction system based on the monitored electrical activity during the plurality of diagnostic AV delayed delivery VfA pacing therapies comprises: determining whether the VfA pacing therapy has captured the cardiac conduction system based on the EHI.

[0188] Example 8: The system or method according to any one of Examples 7, wherein delivering VfA pacing therapy with multiple diagnostic AV delays comprises: reducing the diagnostic AV delays over time, and

[0189] a. Determining whether the VfA pacing therapy has captured the cardiac conduction system based on the EHI includes: if the EHI changes as the AV delay decreases, then it is determined that the VfA pacing therapy has not captured the cardiac conduction system.

[0190] Example 9: A system or method according to any one of Examples 1 to 2 and 4 to 8, wherein the plurality of electrodes comprises one or more implantable electrodes.

[0191] Example 10: A system, method, or apparatus according to any one of Examples 1 to 9, wherein delivery of VfA pacing therapy with multiple diagnostic AV delays comprises: reducing the diagnostic AV delays over time, and

[0192] a. Determining whether the VfA pacing therapy has captured the cardiac conduction system based on the monitored electrical activity during the delivery of the plurality of diagnostic AV delays includes determining that the VfA pacing therapy has not captured the cardiac conduction system if one or both of the cardiac signal morphology and duration of the monitored electrical activity change with a decrease in the current AV delay.

[0193] Example 11: A system, method, or apparatus according to any one of Examples 1 to 10, wherein the computing device is further configured to determine AV blockade based on the monitored electrical activity during the plurality of diagnostic AV delayed delivery VfA pacing therapies.

[0194] Example 12: According to the system, method, or apparatus of Example 11, AV blockade is determined based on the monitored electrical activity during the plurality of diagnostic AV delayed delivery VfA pacing therapies: AV blockade is determined if the following conditions are met:

[0195] a. As the current AV delay decreases, one or all of the monitored electrical activity asynchrony, cardiac signal morphology, and cardiac signal duration remain consistent; and

[0196] b. One or all of the monitored asynchrony of electrical activity, cardiac signal morphology, and cardiac signal duration are above the selected AV blocking threshold.

[0197] This disclosure is provided with reference to illustrative embodiments and is not intended to be limiting. As previously described, those skilled in the art will recognize that various other illustrative applications can utilize the beneficial features of the devices and methods described herein using the techniques described herein. Various modifications to the illustrative embodiments and further embodiments of this disclosure will become apparent in this specification.

Claims

1. A medical system comprising: An electrode device comprising a plurality of electrodes for monitoring electrical activity from a patient’s tissues; as well as A computing device, comprising a processing circuitry system, coupled to the electrode device and configured to: During atrial-to-ventricular VfA pacing therapy with multiple diagnostic AV delays, the patient's cardiac electrical activity is monitored using one or more of the multiple electrodes, each of which is less than the patient's inherent AV delay; and Whether the VfA pacing therapy has successfully captured the cardiac conduction system is determined based on the electrical activity monitored during the multiple diagnostic AV delayed delivery VfA pacing therapies.

2. The medical system of claim 1, wherein the system further comprises a VfA pacing therapy device, wherein the VfA pacing therapy device includes a tissue puncture electrode implantable through the right atrial endocardium and central fibrous body via the Koch's triangle region of the right atrium to deliver the VfA pacing therapy to the left ventricle in the base and / or septum of the left ventricular myocardium of the patient's heart.

3. The medical system according to any one of claims 1 to 2, wherein the longest of the plurality of diagnostic AV delays is less than or equal to 70% of the patient’s inherent AV delay.

4. The medical system according to any one of claims 1 to 2, wherein the plurality of electrodes configured to monitor electrical activity from the patient's tissue comprises a plurality of surface electrodes positioned in an array, the plurality of surface electrodes being configured to be positioned near the skin of the patient's torso.

5. The medical system according to any one of claims 1 to 2, wherein the computing device is further configured to generate electrical heterogeneity information EHI based on the monitored electrical activity during the plurality of diagnostic AV delayed delivery VfA pacing therapies, wherein determining whether the VfA pacing therapy has captured the cardiac conduction system based on the monitored electrical activity during the plurality of diagnostic AV delayed delivery VfA pacing therapies comprises: Based on the EHI, it is determined whether the VfA pacing therapy has captured the cardiac conduction system.

6. The medical system of claim 5, wherein the VfA pacing therapy with multiple diagnostic AV delayed delivery comprises: The diagnostic AV delay decreases over time, and Determining whether the VfA pacing therapy has captured the cardiac conduction system based on the EHI includes: if the EHI changes as the AV delay decreases, then it is determined that the VfA pacing therapy has not captured the cardiac conduction system.

7. The medical system according to any one of claims 1 to 2, wherein the plurality of electrodes comprises one or more implantable electrodes.

8. The medical system according to any one of claims 1 to 2, wherein the VfA pacing therapy delivered in a plurality of diagnostic AV delays comprises: The diagnostic AV delay decreases over time, and Determining whether the VfA pacing therapy has captured the cardiac conduction system based on the monitored electrical activity during the delivery of the plurality of diagnostic AV delays includes: determining that the VfA pacing therapy has not captured the cardiac conduction system if one or both of the cardiac signal morphology and duration of the monitored electrical activity change as the current AV delay decreases.

9. The medical system according to any one of claims 1 to 2, wherein the computing device is further configured to determine AV blockade based on the monitored electrical activity during the plurality of diagnostic AV delayed delivery VfA pacing therapies.

10. The medical system of claim 9, wherein AV blockade is determined based on the monitored electrical activity during the plurality of diagnostic AV delayed delivery VfA pacing therapies: AV blockade is determined if the following conditions are met: As the current AV delay decreases, one or all of the monitored electrical activity asynchrony, cardiac signal morphology, and cardiac signal duration remain consistent; and The detected asynchrony of electrical activity, cardiac signal morphology, and cardiac signal duration, or one or all of these, are above the selected AV blocking threshold.

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