Distinguishing left beam branch region pacing and ventricular interval pacing

Abstract

A processing circuit (50) of a medical system is configured to determine a ventricular activation time metric and determine whether ventricular capture includes left beam branch region pacing or interval pacing based on the ventricular activation time metric. The processing circuitry (50) is further configured to modify an amplitude of the ventricular pacing in response to the ventricular capture comprising interval pacing.

Description

Technical Field

[0001] The present disclosure relates generally to medical device systems. Background Art

[0002] Medical devices can be used to monitor physiological signals of patients. For example, some medical devices are configured to sense electrocardiogram (EGM) signals, which indicate the electrical activity of the heart through electrodes. Some medical devices can be configured to deliver treatment in conjunction with or independently of the monitoring of physiological signals. For example, cardiac pacing is an effective treatment for patients with bradycardia due to sinus node dysfunction or atrioventricular block. However, conventional right ventricular apical pacing (RVAP) can cause electrical and mechanical asynchrony. Summary of the invention

[0003] Conduction system pacing, such as left bundle branch area pacing (LBBAP) therapy, is a physiological pacing method that activates normal cardiac conduction and provides synchronized contraction of the ventricles. LBBAP therapy may include, but is not limited to, left bundle branch (LBB) pacing and left ventricular (LV) septal pacing sufficient to capture LBB fibers. Some medical device systems may lack features that enable monitoring and modification of LBBAP therapy delivery, which may be necessary to ensure that LBBAP therapy is appropriately maintained for a patient.

[0004] In accordance with the techniques of the present disclosure, processing circuitry of a medical device system may be configured to detect a ventricular capture transition between physiological LBBAP and less desirable interval pacing at different pacing amplitudes (e.g., voltages) and generate an output based on a transition pacing threshold. For example, the processing circuitry may determine a ventricular activation time metric and / or a morphology metric. The processing circuitry may determine whether ventricular capture includes LBBAP or interval pacing based on the morphology metric and / or the ventricular activation time metric. In some examples, the processing circuitry may then output a report to a user that includes an indication of whether ventricular capture transitioned between LBBAP and interval pacing and / or the pacing amplitude associated with the transition. In some examples, the processing circuitry may automatically modify the amplitude of ventricular pacing based on the transition between LBBAP and interval pacing. Compared to LBBAP, interval pacing includes pacing of the ventricular septum that is insufficient to capture LBB fibers.

[0005] In an example, a medical device system includes: a medical device configured to deliver ventricular pacing to a patient's heart; a processing circuit configured to: receive electrocardiogram data of the patient sensed by the medical device during delivery of ventricular pacing; identify multiple paced heartbeats within the electrocardiogram data; for each of the multiple heartbeats: determine a ventricular excitation time metric; and determine whether ventricular capture includes left bundle branch area pacing or interval pacing based on the ventricular excitation time metric; and in response to determining that ventricular capture includes interval pacing, modify the amplitude of the ventricular pacing.

[0006] In an example, a method includes: receiving, by a processing circuit of a medical device system that includes the medical device, electrocardiogram data of a patient sensed by a medical device during delivery of ventricular pacing; identifying, by the processing circuit, a plurality of heartbeats within the electrocardiogram data; for each of the plurality of heartbeats: determining, by the processing circuit, a ventricular excitation time metric; and determining, by the processing circuit and based on the ventricular excitation time metric, whether ventricular capture includes left bundle branch area pacing or septal pacing; and in response to determining that ventricular capture includes septal pacing, modifying, by the processing circuit, an amplitude of the ventricular pacing.

[0007] In an example, an implantable medical device includes: a therapy delivery circuit configured to deliver ventricular pacing to a patient's heart; a sensing circuit configured to sense electrocardiogram data of the patient during delivery of the ventricular pacing; a processing circuit configured to: identify multiple heartbeats within the electrocardiogram data; for each of the multiple heartbeats: determine a ventricular excitation time metric; and determine whether ventricular capture includes left bundle branch area pacing or septal pacing based on the ventricular excitation time metric; and in response to determining that ventricular capture includes septal pacing, modify the amplitude of the ventricular pacing.

[0008] The present disclosure is intended to provide an overview of the subject matter described in the present disclosure. The present disclosure is not intended to provide an exclusive or exhaustive explanation of the systems, devices, and methods described in detail in the following figures and description. Further details of one or more examples of the present disclosure are set forth in the following figures and description. Other features, objectives, and advantages will be apparent from the description and drawings, as well as from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1A , Figure 1B and Figure 1C are conceptual diagrams illustrating various exemplary medical systems.

[0010] Figure 2 is a functional block diagram illustrating an exemplary configuration of an implantable medical device (IMD).

[0011] Figure 3is a functional block diagram illustrating an exemplary configuration of an external device.

[0012] Figure 4 is a block diagram illustrating an exemplary system including an access point, a network, an external computing device such as a server, and one or more other computing devices that can interface with the IMD and the external device.

[0013] Figure 5 is a chart illustrating a cardiac EGM including a ventricular pacing event and an exemplary technique for determining whether ventricular capture includes left bundle branch region pacing or septal pacing.

[0014] Figure 6 It is a conceptual diagram of the depolarization waveform.

[0015] Figure 7 is a flow chart of a method for determining whether ventricular capture includes left bundle branch area pacing or septal pacing in accordance with the presently disclosed techniques.

[0016] Figure 8 is a flow chart of a method for determining whether ventricular capture includes left bundle branch area pacing or septal pacing in accordance with the presently disclosed techniques.

[0017] Like reference characters represent like elements throughout the specification and drawings. DETAILED DESCRIPTION

[0018] The present disclosure relates to devices and techniques for classifying pacing capture to assess the effectiveness of conduction system pacing (e.g., LBBAP). LBBAP therapy may include, but is not limited to, left bundle branch (LBB) pacing and left ventricular (LV) septal pacing that is insufficient to capture LBB fibers. LBBAP may be with or without direct bundle capture. An example of LBBAP with direct bundle capture may be pacing septal tissue near the LBB fibers with energy sufficient to capture the LBB fibers. For example, if the electrode is in contact with the LBB or otherwise close to the LBB, less energy may be required to stimulate the LBB so that the LBB can be directly captured. However, if the electrode is too far from the LBB fibers, there may not be enough energy to capture the LBB so that only septal pacing is possible.

[0019] The classification can be based on the cardiac EGM sensed by the medical device that delivers conduction system pacing and / or another medical device. The medical device system can include any one or more medical devices configured to sense the cardiac EGM via implanted or external electrodes to implement the techniques of the present disclosure for detecting ventricular capture transitions between physiological LBBAP and less desirable interval pacing (e.g., LV interval pacing) at different pacing voltages, and vice versa. These techniques include evaluating the cardiac EGM using criteria related to EGM morphology and ventricular excitation time. The techniques of the present disclosure for detecting ventricular capture transitions between LBBAP and interval pacing can facilitate appropriate maintenance of LBBAP therapy for a patient, thereby improving cardiac health.

[0020] Figures 1A to 1C An exemplary medical device system, such as medical device systems 2A-2C (collectively referred to as “medical device system 2”), in accordance with one or more techniques of the present disclosure is shown. The exemplary techniques may be used for implantable medical devices (IMDs), such as Figures 1A to 1C 1 . The medical device system 2 may include the IMD 10 and the external device 12. The IMD 10 may communicate wirelessly with the external device 12 and at least one of the other devices not shown in FIG. 1 . The IMD 10 may be implanted in a patient and coupled to one or more implantable medical leads. The IMD 10 may be configured to sense one or more cardiac EGMs via a plurality of electrodes and deliver conduction system pacing, such as LBBAP.

[0021] External device 12 may be a computing device having a display viewable by a user and an interface (i.e., a user input mechanism) for providing input to external device 12. In some examples, external device 12 may be a laptop computer, a tablet computer, a workstation, one or more servers, a cellular telephone, a personal digital assistant, or another computing device that can run an application that enables the computing device to interact with IMD 10. In some examples, external device 12 may be implemented as a plurality of computing systems configured to receive cardiac electrical signals, which may include at least one EGM signal input received directly or indirectly from IMD 10. In some examples, external device 12 is a computing device included in a remote patient monitoring system, such as the CARELINK®, available from Medtronic, Inc., Minneapolis, Minnesota. TM A computing device is included in the monitoring system.

[0022] External device 12 is configured to communicate with IMD 10 and optionally with another computing device (not shown in FIG. 1 ) via wireless communications. For example, external device 12 may communicate via near field communication techniques (e.g., inductive coupling, NFC, or other communication techniques operable at a range of less than 10 cm to 20 cm) and far field communication techniques (e.g., IEEE 802.11 or IEEE 802.12). RF telemetry or other communication technologies that can operate at a range greater than near field communication technologies) based on a set of specifications.

[0023] The external device 12 may be used to configure the operating parameters of the IMD 10. The external device 12 may be used to retrieve data from the IMD 10. The retrieved data may include values ​​of physiological parameters measured by the IMD 10, indications of arrhythmia or other disease episodes detected by the IMD 10, and physiological signals recorded by the IMD 10. For example, the external device 12 may retrieve information related to ventricular capture transitions between LBBAP and interval pacing (e.g., LV interval pacing) detected by the IMD 10, such as a count or other quantification of such transitions (e.g., over a period of time since the external device last retrieved information) and the pacing amplitudes associated with such transitions. The external device 12 may also retrieve a segment (e.g., a window of data) of the cardiac EGM recorded by the IMD 10 (e.g., because the IMD 10 determined that an arrhythmia or other disease episode occurred during the segment, or in response to a request to record a segment from a patient or other user). As described below with respect to Figure 4 As discussed in greater detail, one or more remote computing devices may interact with IMD 10 over a network in a manner similar to external device 12 , such as to program IMD 10 and / or retrieve data from IMD 10 .

[0024] Processing circuitry of medical device system 2 (e.g., processing circuitry of IMD 10, external device 12, and / or one or more other computing devices) may be configured to perform exemplary techniques of the present disclosure for detecting ventricular capture that switches between LBBAP and septal pacing. In some examples, processing circuitry of system 2 analyzes cardiac EGMs sensed by IMD 10 during delivery of ventricular pacing to determine whether ventricular capture includes LBBAP or septal pacing based on morphology metrics and ventricular activation time metrics. The morphology metrics and / or ventricular activation time metrics are described in more detail below. In brief, determining a morphology metric may include comparing a segment of electrocardiogram data associated with a heartbeat to a template, and determining the morphology metric based on the comparison. Determining the ventricular activation time metric may include determining the center of area under a segment of a depolarization waveform and a maximum ventricular amplitude time for the heartbeat, and determining the ventricular activation time metric for the heartbeat based on the center of area and the maximum ventricular amplitude time.

[0025] Figure 1A 1 is a conceptual diagram of a medical device system 2A capable of pacing and sensing in a patient's heart 8. System 2A may include an IMD 10A coupled to heart 8 via transvenous electrical leads 16, 17, and 18. IMD 10A may be coupled to heart 8 via transvenous electrical leads 16, 17, and 18. Figure 1A 10A is shown as a dual-chamber device configured to deliver cardiac pacing pulses and sense cardiac electrical signals from the right atrium (RA) and ventricular chambers. Housing 15 can enclose internal circuitry corresponding to various circuits and components for sensing cardiac signals from heart 8 and delivering cardiac pacing therapy. In some examples, IMD 10A can be configured to detect tachyarrhythmias from sensed cardiac signals and deliver a high-voltage cardioversion / defibrillation (CV / DF) shock to heart 8, e.g., for terminating a detected ventricular tachycardia or ventricular fibrillation.

[0026] Lead 16 can be an RA lead ("RA lead 16") and lead 18 can be a ventricular conduction system pacing lead ("VCS pacing lead 18"). RA lead 16 and VCS pacing lead 18 can be advanced transvenously to position electrodes for sensing cardiac electrical signals and delivering pacing therapy. RA lead 16 can be positioned so that its distal end is near the right atrium. RA lead 16 can carry a pacing electrode 20 and a sensing electrode 22, both of which are shown as a tip electrode and a ring electrode spaced proximally from tip electrode 20, respectively. Electrodes 20 and 22 provide sensing and pacing in the RA and are each connected to a corresponding insulated conductor extending within the elongated body of RA lead 16. Each insulated conductor is connected at its proximal end to a connector carried by proximal lead connector 40. IMD 10A may include a connector block configured to receive a lead connector 40 for electrically coupling conductors extending from distal electrodes 20 and 22 to circuitry within housing 15 via electrical feedthroughs passing through housing 15 .

[0027] As shown, from a right atrial approach, the VCS lead 18 can be advanced within the right atrium to position a tip electrode 32 and a ring electrode 34 for pacing and sensing near the VCS (e.g., at or near the His bundle). The VCS tip electrode 32 can be a spiral electrode that is advanced to the lower end of the atrial septum, below the AV node, and near the tricuspid annulus to position the tip electrode 32 in, along, or near the His bundle. The ring electrode 34, spaced proximally from the tip electrode 32, can be used as a return electrode, together with the cathode tip electrode 32, for pacing the right and left ventricles via the native His-Purkinje conduction system.

[0028] IMD 10A may generate intracardiac electrogram (EGM) signals from cardiac electrical signals received via a vector of sensing electrodes, which may include tip electrode 32 and / or ring electrode 34 of VCS lead 18. Electrodes 32 and 34 are coupled to respective insulated conductors extending within the elongated body of VCS lead 18, which provide electrical connections to a proximal lead connector 44 coupled to circuitry of IMD 10A.

[0029] Housing 15 may act as a return electrode for use with any of the electrodes carried by leads 16 and 18 in a unipolar sensing or pacing configuration. Electrodes 32 and 34 may be used in a bipolar pacing electrode pair for delivering VCS pacing pulses and for receiving cardiac electrical signals to sense intrinsic and pacing-induced QRS waveforms. In some examples, IMD 10A may be configured to sense far-field (FF) cardiac signals, for example, using electrodes 32 and housing 15 or using electrodes 34 and housing 15, and / or to sense near-field (NF) cardiac signals, for example, using electrodes 32 and 34, for processing and analysis to determine capture type. Electrodes 32 and 34 may be used in a sensing electrode vector for sensing intrinsic R waves for determining cardiac rhythm and the need for electrical stimulation therapy.

[0030] In addition to pacing and sensing capabilities, in some examples, IMD 10A may also be capable of delivering a high voltage cardioversion or defibrillation (CV / DF) shock. In this case, IMD 10A may be coupled to at least one lead carrying one or more defibrillation electrodes, which may be elongated coil electrodes for delivering a high voltage CV / DF shock. Figure 1A In the example of , third lead 17 is shown as being connected to IMD 10A, with its distal end advanced into the right ventricle (RV). RV lead 17 can include a coil electrode 24 for delivering CV / DF shocks, for example in combination with housing 15. Housing 15 can be used as an active electrode together with coil electrode 24 during CV / DF shock delivery. RV lead 17, when present, can carry a distal tip electrode 28 and a ring electrode 30 for delivering ventricular pacing pulses in the RV and / or sensing cardiac electrical signals from the RV. Electrodes 28, 30, and 24 are each connected to a corresponding insulated conductor extending within the elongated body of RV lead 17. Each insulated conductor can be connected at its proximal end to a connector carried by proximal lead connector 42. In other examples, RV lead 17 is optional. When IMD 10A is implemented as an implantable cardioverter-defibrillator (ICD) having CV / DF shocking capability in addition to cardiac pacing and sensing functions, one or more CV / DF electrodes may be carried by RA lead 16 and / or VCS lead 18 .

[0031] It should be understood that although the IMD 10A is described as a dual-chamber pacemaker with or without CV / DF shock capability that is capable of sensing and pacing the RA via VCS and sensing ventricular signals and pacing the ventricular chambers, the IMD 10A may be a single-chamber pacing device with single-chamber or dual-chamber sensing. For example, the IMD 10A may be connected only to the VCS lead 18 to sense cardiac electrical signals and deliver VCS pacing pulses to at least maintain a minimum ventricular rate. When the lead 18 is positioned for delivering VCS pacing pulses, the VCS lead 18 may carry an additional sensing electrode positioned within the RA for sensing the RA EGM signal, enabling the IMD 10A to perform dual-chamber (atrial P wave and ventricular R wave) sensing and VCS pacing, which may be atrial-synchronous ventricular pacing delivered via the His-Purkinje system.

[0032] Figure 1B 1 is a conceptual diagram of a medical device system 2B. System 2B may include an IMD 10B coupled to a VCS lead 18 that is advanced to an alternate location within heart 8 for delivering VCS pacing pulses and sensing cardiac electrical signals. In this example, a distal portion of VCS lead 18 is advanced within the right ventricle (RV) from a right ventricular approach for sensing cardiac electrical signals and delivering VCS pacing pulses at or near the His bundle. IMD 10B may be a single chamber device coupled only to VCS lead 18. In other examples, IMD 10B may be a dual chamber device and coupled to RA lead 16 ( Figure 1A ) and VCS lead 18 to enable sensing of atrial P waves and delivery of atrial pacing pulses in an atrioventricular synchronous pacing mode and to deliver VCS pacing pulses at an AV delay after an atrial event (sensed or paced).

[0033] exist Figure 1B In an example of , the tip electrode 32 of the VCS lead 18 is placed in the ventricular septum 19, for example, high along the ventricular septum near the lower portion of the His bundle. The tip electrode 32 can be paired with a return anode ring electrode 34 for delivering VCS pacing pulses and for sensing raw cardiac electrical signals, which can be processed to obtain NFEGM signals. In some examples, the post-pacing NF EGM signal can be provided as an input to the PCC 51 to classify the capture type using the techniques disclosed herein. The tip electrode 32 or the ring electrode 34 can be paired with the IMD housing 15 to receive the raw cardiac electrical signals, which are processed to obtain the FF EGM signal.

[0034] In some examples, VCS pacing can be delivered in combination with LV myocardial pacing, which can be delivered via LV lead 46 for use in further improving mechanical synchronization of the RV and LV, for example, during cardiac resynchronization therapy (CRT). LV lead 46 can be advanced into the RA, through the coronary sinus ostium and into the cardiac veins of the LV to position electrodes 48a, 48b, 48c, and 48d (collectively, "LV electrodes 48") along the LV myocardium to sense ventricular electrical signals and pace the LV myocardium. LV lead 46 is positioned at the RA, through the coronary sinus ostium, and into the cardiac veins of the LV. Figure 1B 4 is a quadripolar lead shown as carrying four electrodes 48a-48d, which may be selected from a variety of bipolar pacing electrodes for pacing LV myocardial tissue and sensing LV signals. One of the LV electrodes 48 may be selected in combination with the pacemaker housing 15 for delivering unipolar LV myocardial pacing in some cases and / or for sensing raw cardiac electrical signals, which may be processed and analyzed as FF EGM signals.

[0035] When the VCS lead 18 is positioned for delivering His bundle or bundle branch pacing of one or both bundle branches, VCS pacing can be combined with ventricular myocardial pacing of the LV (using the LV lead 46) to correct LV conduction delays and achieve electrical and mechanical synchronization of the ventricles. Thus, in some examples, the IMD 10B can control the delivery of VCS pacing pulses combined with LV myocardial pacing pulse delivery at a specific time interval, which can include an AV delay and / or a VV delay. The AV delay can control the timing of the VCS pulse and / or the LV myocardial pacing pulse relative to an atrial event (e.g., a sensed P wave or a delivered atrial pacing pulse). In some examples, the VV delay can control the timing between the VCS pacing pulse delivered via the VCS lead 18 and the LV myocardial pacing pulse delivered via the LV lead 46.

[0036] It should be understood that LV lead 46 is optional. In some examples, IMD 10B is coupled only to VCS lead 18, which is advanced into the RA or RV for delivery of VCS pacing and sensing of ventricular EGM signals. In other examples, Figure 1A RA lead 16 shown in the figure is implanted in combination with VCS lead 18 advanced into the RA or RV for delivery of VCS pacing in a dual chamber sensing and pacing system. External device 50 can receive one or more EGM signals sensed using any available ventricular EGM sensing electrode vectors from IMD 10B for processing and analysis according to the techniques disclosed herein.

[0037] Figure 1C is a conceptual diagram of a medical device system 2C. System 2C may include an IMD 10C. Figure 1CIn the example of , IMD 10C includes VCS lead 18 coupled to IMD 10C. Figure 1C , the IMD 10C is a dual chamber device configured to receive RA lead 16, which can be positioned in the right atrial chamber to deliver atrial pacing pulses and sense atrial electrical signals via electrodes 20 and 22. The IMD 10C can be configured to sense intrinsic atrial P waves, and deliver atrial pacing pulses in the absence of sensed P waves. The IMD 10C can be configured to deliver atrial synchronized ventricular pacing by setting an AV delay in response to each sensed P wave or delivered atrial pacing pulse and deliver a ventricular pacing pulse to the VCS via lead 18 at the end of the AV delay.

[0038] The VCS lead 18 may be advanced transvenously through the RA into the RV to position the tip electrode 32 within the ventricular septum 19, such as the ventricular venous septum 19. Figure 1B The implantation position shown in FIG. 1 is relatively low (located below). When the tip electrode 32 is relatively advanced upward in the ventricular septum 19 (as shown in FIG. 1 ), the tip electrode 32 is relatively advanced upward in the ventricular septum 19 (as shown in FIG. 1 ). Figure 1B As shown in FIG. 1 , the tip electrode 32 may be positioned along the lower portion of the His bundle for delivering pacing pulses for fully or partially capturing the His bundle. Figure 1C In the present invention, the tip electrode 32 can be advanced within the ventricular septum 19 near the bundle branches of the His-Purkinje system (e.g., at the LBB pacing site in the LBB region or at the right bundle branch RBB pacing site in the RBB region) for delivering pacing pulses to capture one or both bundle branches in the region of the LBB and / or RBB.

[0039] In various examples, the tip electrode 32 may be selected as a pacing cathode electrode, combined with the ring electrode 34 as a return anode electrode, for pacing and capturing the LBB and / or RBB. In some cases, the pacing pulse amplitude and pulse width may be selected to achieve cathode capture at the cathode electrode for capturing at least one bundle branch. In other cases, the pacing pulse amplitude and pulse width may be selected to achieve cathode and anode capture, which may simultaneously capture both the LBB and the RBB to provide dual or bilateral bundle branch (BB) pacing using a single bipolar electrode pair. In other examples, the tip electrode 32 or the ring electrode 34 may be selected as a cathode electrode paired with the housing 15 in a unipolar pacing electrode vector. Unipolar pacing may capture a single BB. However, in some cases, when a unipolar pacing pulse directly captures one bundle branch, unipolar pacing may capture both the RBB and the LBB, while a virtual current or disconnected excitation generated by the pacing electrode may excite another bundle branch, thereby potentially causing unipolar bilateral BB pacing while capturing both the LBB and the RBB.

[0040] Although the VCS lead 18 is shown as carrying a pacing and sensing electrode pair (i.e., a tip electrode 32 and a ring electrode 34), it should be understood that in other examples, the VCS lead 18 may include multiple electrodes along its distal portion to provide one or more selectable bipolar pacing electrode vectors and / or one or more unipolar pacing electrode vectors (e.g., in conjunction with the housing 15) for delivering pacing pulses to one or both of the RBB and the LBB.

[0041] In addition, when IMD 10C is configured as an ICD capable of delivering high voltage shock therapy, VCS lead 18 may include one or more coil electrodes, such as coil electrode 35. Coil electrode 35 may be used in a sensing electrode vector, such as with either tip electrode 32 or ring electrode 34, to sense ventricular EGM signals that may be analyzed by PCC 51 to classify VCS pacing pulse capture types.

[0042] As described above, IMD 10C may communicate with external device 12 via wireless telemetry. External device 12 may receive information from IMD 10C using Figure 1C Any EGM signals sensed by electrodes shown in or described in other examples or shown in the accompanying drawings may be processed and analyzed according to the techniques disclosed herein.

[0043] Although IMD 10 is generally described herein as a pacemaker that delivers conduction system pacing and determines whether the pacing produces effective conduction system pacing, exemplary systems including one or more implanted or external devices of any type configured to sense cardiac EGMs may be configured to implement the techniques of the present disclosure.

[0044] Figure 2 1 is a functional block diagram illustrating an exemplary configuration of IMD 10 of FIG. 1 in accordance with one or more techniques described herein. In the illustrated example, IMD 10 includes electrodes 51, which may be located on one or more leads (e.g., lead 16) and / or a housing (e.g., housing 15) of IMD 10, processing circuitry 50, sensing circuitry 52, communication circuitry 54, storage device 56, therapy delivery circuitry 58, and sensor 62. Electrode 51 may include electrodes described herein, such as electrodes 20, 22, 28, 30, 32, 34, 48, and the like.

[0045] Processing circuitry 50 may include fixed function circuitry and / or programmable processing circuitry. Processing circuitry 50 may include any one or more of a microprocessor, a controller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or equivalent discrete or analog logic circuitry. In some examples, processing circuitry 50 may include multiple components (such as any combination of one or more microprocessors, one or more controllers, one or more DSPs, one or more ASICs, or one or more FPGAs) and other discrete or integrated logic circuitry. The functionality attributed to processing circuitry 50 herein may be embodied in software, firmware, hardware, or any combination thereof.

[0046] The sensing circuit 52 can be connected to the electrode 51. The sensing circuit 52 can sense signals from the electrode 51, for example to generate a cardiac EGM to facilitate monitoring of the electrical activity of the heart. As an example, the sensing circuit 52 can also monitor signals from the sensor 62, which can include one or more accelerometers, pressure sensors, and / or optical sensors. In some examples, the sensing circuit 52 may include one or more filters and amplifiers for filtering and amplifying signals received from the electrode 51 and / or the sensor 62. The sensing circuit 52 may include a switching circuit for selecting the electrode 51 and its polarity to sense the cardiac EGM signal described herein.

[0047] Sensing circuit 52 and / or processing circuit 50 may be configured to detect cardiac depolarization (e.g., a P wave for atrial depolarization or an R wave for ventricular depolarization) when the cardiac EGM amplitude exceeds a sensing threshold. In some examples, for cardiac depolarization detection, sensing circuit 52 may include a rectifier, a filter, an amplifier, a comparator, and / or an analog-to-digital converter. In some examples, sensing circuit 52 may output an indication to processing circuit 50 in response to sensing of cardiac depolarization. In this way, processing circuit 50 may receive detected cardiac depolarization indications corresponding to the occurrence of detected R-waves and P waves in corresponding chambers of the heart. Processing circuit 50 may use the indications of detected R-waves and P waves to determine depolarization intervals, heart rate, and detect cardiac arrhythmias, such as tachyarrhythmias and asystole.

[0048] Sensing circuitry 52 may also provide one or more digitized cardiac EGM signals to processing circuitry 50 for analysis. For example, processing circuitry 50 may use the digitized cardiac EGM signals in rhythm differentiation and / or determine whether ventricular capture is switching between LBBAP and septal pacing in accordance with techniques of the present disclosure. In some examples, processing circuitry 50 may store the digitized cardiac EGMs in storage device 56. In accordance with techniques of the present disclosure, processing circuitry 50 of IMD 10 and / or processing circuitry of another device that retrieves data from IMD 10 may analyze the cardiac EGMs to determine whether ventricular capture is switching between LBBAP and septal pacing.

[0049] Communication circuitry 54 may include any suitable hardware, firmware, software, or any combination thereof, for communicating with another device, such as external device 12, another networked computing device, or another IMD or sensor. Under the control of processing circuitry 50, communication circuitry 54 may receive downlink telemetry from external device 12 or another device and transmit uplink telemetry to the external device or another device via an internal or external antenna. Among other things, processing circuitry 50 may communicate with external devices (e.g., external device 12) and computer networks (such as Medtronic The communication circuit 54 may be configured to transmit and / or receive signals via inductive coupling, electromagnetic coupling, near field communication (NFC), radio frequency (RF) communication, Bluetooth, WiFi, or other proprietary or non-proprietary wireless communication schemes.

[0050] In some examples, storage device 56 includes computer-readable instructions that, when executed by processing circuit 50, cause IMD 10 and processing circuit 50 to perform various functions attributed to IMD 10 and processing circuit 50 herein. Storage device 56 may include any volatile, non-volatile, magnetic, optical, or electrical media, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), electrically erasable programmable ROM (EEPROM), flash memory, or any other digital media. As an example, storage device 56 may store programmed values ​​for one or more operating parameters of IMD 10 and / or data collected by IMD 10 for transmission to another device using communication circuit 54. Data stored by storage device 56 and transmitted by communication circuit 54 to one or more other devices may include, for example, a digitized cardiac EGM, and data regarding switching between LBBAP and interval pacing as described herein.

[0051] The processing circuit 50 can be configured to control the therapy delivery circuit 58 to generate electrical therapy and deliver the electrical therapy to the patient's heart 8 via the electrodes 51. The electrical therapy may include, for example, pacing pulses or any other suitable electrical stimulation. The processing circuit 50 may control the therapy delivery circuit 58 to deliver electrical stimulation therapy via the electrodes 51 according to one or more therapy parameter values ​​that may be stored in the storage device 56. In the case of pacing pulses, the therapy parameter values ​​may include amplitude values, such as pulse amplitude (e.g., stimulation voltage amplitude) and width. In some examples, the therapy delivery circuit 58 may include a capacitor, a current source, and / or a regulator. The therapy delivery circuit 58 may include a switching circuit for selecting the electrodes 51 and their polarity to deliver therapy signals to the heart 8.

[0052] Figure 3 1 is a block diagram showing an exemplary configuration of components of the external device 12. Figure 3 In the example of FIG. 8 , the external device 12 includes a processing circuit 80 , a communication circuit 82 , a storage device 84 , and a user interface 86 .

[0053] The processing circuit 80 may include one or more processors configured to implement functions and / or processing instructions for execution within the external device 12. For example, the processing circuit 80 is capable of processing instructions stored in the storage device 84. The processing circuit 80 may include, for example, a microprocessor, a DSP, an ASIC, an FPGA, or an equivalent discrete or integrated logic circuit or a combination of any of the foregoing devices or circuits. Thus, the processing circuit 80 may include any suitable structure, whether hardware, software, firmware, or any combination thereof, to perform the functions attributed to the processing circuit 80 herein.

[0054] The communication circuit 82 may include any suitable hardware, firmware, software, or any combination thereof for communicating with another device such as the IMD 10. Under the control of the processing circuit 80, the communication circuit 82 may receive downlink telemetry from the IMD 10 or another device, and send uplink telemetry to the IMD or another device. The communication circuit 82 may be configured to transmit or receive signals via inductive coupling, electromagnetic coupling, near field communication (NFC), radio frequency (RF) communication, Bluetooth, WiFi, or other proprietary or non-proprietary wireless communication schemes. The communication circuit 82 may also be configured to communicate with a device other than the IMD 10 via any of various forms of wired and / or wireless communications and / or network protocols.

[0055] Storage device 84 may be configured to store information within external device 12 during operation. Storage device 84 may include a computer-readable storage medium or a computer-readable storage device. In some examples, storage device 84 includes one or more of short-term memory or long-term memory. Storage device 84 may include, for example, RAM, DRAM, SRAM, a magnetic disk, an optical disk, flash memory, or various forms of EPROM or EEPROM. In some examples, storage device 84 is used to store data indicating instructions for execution by processing circuit 80. Storage device 84 may be used by software or applications running on external device 12 to temporarily store information during program execution.

[0056] The data exchanged between the external device 12 and the IMD 10 may include operating parameters. The external device 12 may transmit data including computer-readable instructions that, when implemented by the IMD 10, may control the IMD 10 to change one or more operating parameters and / or export collected data. For example, the processing circuit 80 may transmit an instruction to the IMD 10 requesting the IMD 10 to export collected data (e.g., transition detection data and / or digitized cardiac EGM) to the external device 12. In turn, the external device 12 may receive the data collected from the IMD 10 and store the collected data in the storage device 84. The processing circuit 80 may implement any of the techniques described herein to analyze the cardiac EGM received from the IMD 10, for example to determine whether ventricular capture is switching between LBBAP and interval pacing according to the techniques of the present disclosure. In some examples, the processing circuit 80 of the external device 12 may initiate and control the execution of tests of various pacing amplitudes to identify a transition between LPPAP pacing and interval pacing.

[0057] A user, such as a clinician or patient, may interact with the external device 12 via the user interface 86. The user interface 86 includes a display (not shown), such as a liquid crystal display (LCD) or light emitting diode (LED) display or other type of screen, which the processing circuit 80 may use to present information related to the IMD 10, such as a cardiac EGM, an indication of the detection of the ventricular capture switching between LBBAP and interval pacing. In addition, the user interface 86 may include an input mechanism for receiving input from the user. The input mechanism may include, for example, any one or more of a button, a keypad (e.g., an alphanumeric keypad), a peripheral pointing device, a touch screen, or another input mechanism that allows a user to navigate through a user interface presented by the processing circuit 80 of the external device 12 and provide input. In other examples, the user interface 86 also includes an audio circuit for providing auditory notifications, instructions or other sounds to the user, receiving voice commands from the user, or both.

[0058] Figure 4is a block diagram illustrating an exemplary system including access point 90, network 92, external computing devices (such as server 94), and one or more other computing devices 100A-100N (collectively, “computing devices 100”) that may be coupled to IMD 10 and external device 12 via network 92, in accordance with one or more techniques described herein. In this example, IMD 10 may use communication circuitry 54 to communicate with external device 12 via a first wireless connection and to communicate with access point 90 via a second wireless connection. Figure 4 In the example of FIG. 1 , access point 90 , external device 12 , server 94 , and computing device 100 are interconnected and can communicate with each other via network 92 .

[0059] The access point 90 may include a device that is connected to the network 92 via any of a variety of connections, such as a telephone dial-up, a digital subscriber line (DSL), or a cable modem connection. In other examples, the access point 90 may be coupled to the network 92 via different forms of connection, including a wired connection or a wireless connection. In some examples, the access point 90 may be a user device that can be co-located with the patient, such as a tablet or a smart phone. The IMD 10 may be configured to send data to the access point 90, such as data regarding the conversion between LBBAP and interval pacing and / or the identification of a cardiac EGM. The access point 90 may then transmit the retrieved data to the server 94 via the network 92.

[0060] In some cases, server 94 may be configured to provide a secure storage site for data that has been collected from IMD 10 and / or external devices 12. In some cases, server 94 may compile the data in a web page or other document via computing device 100 for viewing by a trained professional, such as a clinician. Figure 5 One or more aspects of the illustrated system may be used with a Medtronic It is implemented by the general network technologies and functions similar to those provided by Network.

[0061] In some examples, one or more of the computing devices 100 may be a tablet computer or other smart device located with a clinician, which the clinician may program to receive data from and / or query the IMD 10. For example, the clinician may access data collected by the IMD 10 through the computing device 100, such as when the patient is between clinician visits, to check the status of a medical condition or the operation of the IMD 10. In some examples, the clinician may enter instructions for medical intervention for the patient into an application executed by the computing device 100, such as based on the status of the patient's condition determined by the IMD 10, the external device 12, the server 94, or any combination thereof, or based on other patient data known to the clinician. Subsequently, the device 100 may transmit the instructions for the medical intervention to another computing device of the computing devices 100 located with the patient or the patient's caregiver. For example, such instructions for medical intervention may include instructions to change the dosage, timing, or selection of a medication, instructions to schedule a clinician visit, or instructions to seek medical attention. In further examples, computing device 100 may generate an alert to the patient based on the status of the patient's medical condition, which may enable the patient to proactively seek medical attention prior to receiving instructions for medical intervention. In this manner, the patient may autonomously take action as needed to address his or her medical condition, which may help improve the patient's clinical outcomes. In some examples, a clinician may input instructions via computing device 100 to cause IMD 10 to perform a pacing amplitude test to identify a transition between LBBAP and interval pacing.

[0062] In by Figure 4 In the illustrated example, server 94 includes, for example, a storage device 96 and processing circuitry 98 for storing data retrieved from IMD 10. Figure 4 94, but the computing device 100 may similarly include a storage device and a processing circuit. The processing circuit 98 may include one or more processors configured to implement functions and / or process instructions for execution within the server 94. For example, the processing circuit 98 may be capable of processing instructions stored in the memory 96. The processing circuit 98 may include, for example, a microprocessor, a DSP, an ASIC, an FPGA, or an equivalent discrete or integrated logic circuit or a combination of any of the foregoing devices or circuits. Therefore, the processing circuit 98 may include any suitable structure, whether hardware, software, firmware, or any combination thereof, to perform the functions attributed to the processing circuit 98 herein. The processing circuit 98 of the server 94 and / or the processing circuit of the computing device 100 may implement any of the techniques described herein to analyze the cardiac EGM received from the IMD 10, for example to determine whether ventricular capture is switching between LBBAP and interval pacing according to the techniques of the present disclosure.

[0063] Storage device 96 may include a computer-readable storage medium or a computer-readable storage device. In some examples, memory 96 includes one or more of short-term memory or long-term memory. Storage device 96 may include, for example, RAM, DRAM, SRAM, a magnetic disk, an optical disk, flash memory, or various forms of EPROM or EEPROM. In some examples, storage device 96 is used to store data indicating instructions for execution by processing circuit 98.

[0064] Figure 5 1 is a diagram illustrating an exemplary cardiac EGM 120 over a plurality of paced cardiac cycles 122A to 122I (collectively, “cardiac cycles 122”) in which IMD 10 delivers ventricular cardiac pacing at different stimulation amplitudes (e.g., different stimulation voltages). In some examples, cardiac EGM 120 is a far-field ventricular EGM, e.g., between electrodes on leads 16 and electrodes on housing 15 of IMD 10. Figure 5 Also shown are exemplary techniques for detecting ventricular capture transitions between LBBAP and septal pacing based on the cardiac EGM 120. The IMD 10 may sense the patient's EGM 120 during delivery of ventricular pacing to the patient (e.g., as part of therapeutic pacing and / or during a threshold detection pacing procedure). The processing circuitry 50 of the IMD 10 may receive the EGM 120 and identify multiple heartbeats and features within the EGM 120. The processing circuitry 50 may analyze analysis windows 123A to 123I (collectively, "analysis windows 123") of the paced cardiac cycle 122 to identify features within the EGM 120.

[0065] According to the techniques of the present disclosure, a processing circuit (e.g., a processing circuit of an IMD 10) uses different features (such as ventricular activation time and / or morphological characteristics) to detect changes in ventricular capture. The IMD 10 senses the cardiac EGM 120 and detects features within an analysis window 123 of a cardiac cycle 122. For each analysis window in the analysis windows 123, the processing circuit 50 may begin collecting a window of EGM 120 after a corresponding pacing voltage is delivered to the heart 8. In other words, for each analysis window in the analysis windows 123, the processing circuit may record a digitized far-field EGM for a predetermined time period shortly after pacing (e.g., to avoid collecting data during pacing). The processing circuit 50 may determine a ventricular activation time metric and / or a morphological metric for each cardiac cycle in the cardiac cycle 122. Based on the ventricular activation time metric and / or the morphological metric, the processing circuit 50 may determine whether ventricular capture includes LBBAP or interval pacing.

[0066] The processing circuit 50 may determine whether ventricular capture includes LBBAP or septal pacing based on a ventricular activation time metric. In some examples, the ventricular activation time metric may be determined based on electrocardiogram (ECG) data and / or EGM data. In the case of EGM data, a parameter in the EGM data may reflect changes in ventricular activation time. For example, the processing circuit 50 may indirectly measure or generate ventricular activation time based on an EGM morphology metric. In any case, the processing circuit 50 may determine a ventricular activation time metric for each heartbeat in a plurality of heartbeats, such as each of the cardiac cycles 122 of the EGM 120. Typically, a relatively small ventricular activation time metric value may indicate that ventricular capture includes LBBAP (rather than septal pacing), and a relatively large ventricular activation time metric may indicate that ventricular capture includes septal pacing (rather than LBBAP).

[0067] In some examples, processing circuitry 50 may determine a ventricular activation time metric for a heartbeat based on the center of area under the segment of the depolarization waveform and the maximum ventricular amplitude time of the heartbeat (e.g., the time between a ventricular pacing event of the heartbeat and the maximum amplitude of the heartbeat). The center of area under the segment of the ventricular depolarization waveform may represent the centroid or geometric center of the segment of the ventricular depolarization waveform. Thus, processing circuitry 50 may determine the center of area using the following formula:

[0068]

[0069] Where X a The time of the center of the area under the segment of the ventricular depolarization waveform is represented by the summation index, the upper and lower limits of the summation correspond to the upper and lower limits of the ventricular depolarization waveform domain, and z(i) represents the amplitude of the ventricular depolarization waveform as a function of the summation index. Additionally or alternatively, any other formula for calculating the arithmetic mean position of a geometric figure may be used to calculate the center of the area under the segment of the ventricular depolarization waveform. Figure 6 Techniques for calculating the center of area are discussed in more detail.

[0070] Processing circuit 50 may determine the ventricular activation time metric for a heartbeat based on the center of area under the segment of the depolarization waveform and the maximum ventricular amplitude time of the heartbeat. In some cases, processing circuit 50 may determine the ventricular activation time metric using the following formula:

[0071] t4=t 最大 -X a

[0072] where t4 represents an example of a ventricular activation time metric that may represent both left and right ventricular activation times from a far-field EGM, and t 最大 represents the maximum ventricular amplitude time, X aThe time at which the center of the area under the segment of the ventricular depolarization waveform is represented. Figure 5 As shown in , in some examples, the processing circuit 50 can calculate T4R. T4R can represent another example of a metric for ventricular activation time. The processing circuit 50 can calculate T4R by determining a ratio of a corresponding t4 of a heartbeat (e.g., cardiac cycle 122C) and a t4 of a template. The template can represent a window of waveform data collected for one or more heartbeats known to be LBBAP (e.g., due to the IMD 10 delivering a high pacing voltage, such as 5V, to the heart 8). In other words, the processing circuit 50 can compare the cardiac cycle 122 to a template of one or more collected and stored patient EGM data associated with a heartbeat known or otherwise confirmed to be LBBAP.

[0073] A relatively small ventricular activation time metric value may indicate a higher likelihood that ventricular capture includes LBBAP (rather than septal pacing), and a relatively large ventricular activation time metric may indicate that ventricular capture includes septal pacing (rather than LBBAP). Thus, the processing circuit 50 may use an algorithm based on the ventricular activation time metric (e.g., t4 and / or T4R) to determine whether ventricular capture includes LBBAP or septal pacing. For example, if the t4 and / or T4R values ​​are above the corresponding ventricular activation time thresholds, the processing circuit 50 may determine that ventricular capture includes septal pacing. On the other hand, if the t4 and / or T4R values ​​are below the corresponding ventricular activation time thresholds, the processing circuit 50 may determine that ventricular capture includes LBBAP. An exemplary threshold value for t4 may be a value between approximately 50 and approximately 350 milliseconds (ms). An exemplary threshold value for the T4R threshold may be a value between approximately 0.8 and 1.5. However, the present disclosure contemplates other thresholds.

[0074] Processing circuitry 50 may determine whether ventricular capture includes LBBAP or septal pacing based on the morphology metric. In some examples, processing circuitry 50 may determine the morphology metric by comparing a corresponding analysis window to a template for each of cardiac cycles 122. For example, IMD 10 may collect EGM 120 of sensed cardiac cycles 122 and compare each of cardiac cycles 122 in EGM 120 to the template. Based on the comparison, processing circuitry 50 may output a morphology metric value, such as Figure 5. The morphology metric can have a range from 0% to 100%, and the match metric value can indicate the similarity between the corresponding ventricular pacing beat and the template. For example, a match metric value of 100% can indicate a nearly identical match, and a value less than 100% can indicate a relatively large difference between the two waveforms. A cardiac cycle with a relatively large match metric (e.g., a high similarity between the waveforms) can indicate a high likelihood that the ventricular capture includes LBBAP, while a cardiac cycle with a relatively small match metric (e.g., a low similarity between the waveforms) can indicate a low likelihood that the ventricular capture includes LBBAP.

[0075] In some examples, determining the similarity between the cardiac cycle 122 and the template may require performing a time-frequency decomposition using a technique such as a wavelet transform. An exemplary wavelet transform algorithm may involve calculating wavelet transform coefficients for the cardiac cycle 122 and extracting coefficients that describe significant features of a waveform associated with the cardiac cycle 122. The processing circuit 50 may compare the coefficients of the cardiac cycle 122 with the coefficients of the template to calculate a corresponding matching metric for the cardiac cycle 122. For details on the calculation of the matching metric, refer to U.S. Patent No. 7,826,893 and U.S. Patent No. 7,706,869. In short, if the wavelet coefficients numerically match and the coefficients have similar absolute amplitudes, the matching weights of the coefficients are added to determine the matching metric.

[0076] A relatively large match metric value may indicate a greater similarity between the cardiac cycle and the template than a relatively small match metric value. Figure 5 In the example of , cardiac cycle 122A having a match metric value of 100 may be more similar to the template than cardiac cycle 122B having a match metric value of 82.

[0077] In some cases, processing circuitry 50 may determine whether ventricular capture includes LBBAP or septal pacing by determining whether the morphology metric satisfies a morphology condition. Processing circuitry 50 may determine that the morphology metric satisfies the morphology condition when the match metric value is equal to or greater than a threshold value (e.g., 70%). Thus, satisfaction of the morphology condition may indicate a substantially normal ECG morphology. In some examples, the threshold value may be expressed in a format other than a percentage (e.g., an absolute value).

[0078] A relatively large match metric value may indicate a higher likelihood that ventricular capture includes LBBAP (rather than septal pacing), and a relatively small match metric value may indicate a higher likelihood that ventricular capture includes septal pacing (rather than LBBAP). At the same time, a relatively small ventricular activation time metric value may indicate a higher likelihood that ventricular capture includes LBBAP (rather than septal pacing), and a relatively large ventricular activation time metric may indicate that ventricular capture includes septal pacing (rather than LBBAP). In this way, processing circuitry 50 may use an algorithm based on both the morphology metric (e.g., the match metric) and the ventricular activation time metric (e.g., t4 and / or T4R) to determine whether ventricular capture includes LBBAP or septal pacing.

[0079] For example, in response to determining that the morphology metric satisfies the morphology condition (e.g., the match metric value is equal to or greater than 70), indicating a high likelihood that ventricular capture includes LBBAP, the processing circuit 50 may determine whether the ventricular activation time metric value is greater than a first threshold. An exemplary first t4 threshold may be 350 ms, and an exemplary first T4R threshold may be 1.5. However, other thresholds are contemplated by the present disclosure. A ventricular activation time metric (greater than a first ventricular activation time threshold) may indicate a low likelihood that ventricular capture includes LBBAP and may instead include septal pacing.

[0080] Conversely, in response to determining that the morphology metric does not satisfy the morphology condition, indicating a low likelihood that ventricular capture includes LBBAP, processing circuitry 50 may determine whether the ventricular activation time metric value is greater than a second threshold. A ventricular activation time metric value greater than the second threshold may indicate interval pacing. The first threshold may be greater than the second threshold. This may be because when the morphology metric satisfies the morphology condition (which favors a determination that ventricular capture includes LBBAP), a greater ventricular activation time may be required to overturn such a determination and cause processing circuitry 50 to determine instead that ventricular capture includes interval pacing. An exemplary second t4 threshold may be 200 ms, and an exemplary second T4R threshold may be 1.1.

[0081] Processing circuitry 50 may use the techniques of the present disclosure to determine whether ventricular capture includes LBBAP or septal pacing in various situations. For example, when performing an initial capture detection, processing circuitry 50 may determine whether ventricular capture includes LBBAP or septal pacing. IMD 10 may perform an initial capture detection by delivering a stimulation voltage having an initial amplitude (e.g., 5V) that ensures ventricular capture of LBBAP. Processing circuitry 50 may collect one or more templates during the initial capture detection (e.g., when IMD 10 is delivering a stimulation voltage having an initial amplitude that ensures ventricular capture of LBBAP). In some examples, processing circuitry 50 may cross-compare the collected templates to ensure fit.

[0082] IMD 10 may gradually reduce (e.g., step down) the stimulation voltage from an initial amplitude. IMD 10 may do so when performing initial capture detection. For each cardiac cycle, processing circuitry 50 may determine whether ventricular capture includes LBBAP or septal pacing using the techniques of the present disclosure. Ventricular capture may switch from LBBAP to septal pacing when the stimulation voltage decreases to a certain voltage threshold (e.g., because the amplitude of the stimulation voltage is now insufficient to induce LBBAP).

[0083] In another instance, IMD 10 can provide therapy to the patient by delivering stimulation pulses at a set (e.g., predetermined, constant, etc.) voltage. Processing circuitry 50 can use the techniques of the present disclosure to determine whether ventricular capture includes LBBAP or septal pacing to monitor LBBAP therapy delivery and whether LBBAP therapy is being appropriately maintained for the patient.

[0084] In any case, processing circuit 50 may perform at least one action based on determining whether ventricular capture includes LBBAP or septal pacing. For example, processing circuit 50 may output a report based on the determination of multiple paced beats, the report including an indication of whether ventricular capture transitioned between LBBAP and septal pacing.

[0085] For example, refer to Figure 5 , the processing circuit 50 may determine that the matching metric value for cardiac cycle 122A is 100 and the T4R value is 1, the matching metric value for cardiac cycle 122B is 82 and the T4R value is 1.05, the matching metric value for cardiac cycle 122C is 82 and the T4R value is 1.05, the matching metric value for cardiac cycle 122D is 88 and the T4R value is 1.06, the matching metric value for cardiac cycle 122E is 76 and the T4R value is 1.06, the matching metric value for cardiac cycle 122F is 52 and the T4R value is 1.21, the matching metric value for cardiac cycle 122G is 52 and the T4R value is 1.18, and the matching metric value for cardiac cycle 122H is 49 and the T4R value is 1.19. In this example, the morphology condition threshold may be 70, the first ventricular activation time threshold may be a T4R value of 1.17, and the second ventricular activation time threshold may be a T4R value of 1.03. Thus, processing circuitry 50 may determine that cardiac cycles 122A-122E exhibit ventricular capture including LBBAP (e.g., as determined by Figure 5 ), and cardiac cycles 122F to 122H demonstrate ventricular capture including septal pacing (e.g., by Figure 5 The “Algo” value in 3 indicates that

[0086] exist Figure 5In the example of , ventricular capture transitioned between LBBAP and septal pacing at cardiac cycle 122F. Thus, in this example, processing circuitry 50 may output an indication that ventricular capture transitioned between LBBAP and septal pacing and that the transition occurred at cardiac cycle 122F. The report may also include a threshold voltage or voltage range that indicates a transition between LBBAP and septal pacing or suggests a pacing voltage that provides LBBAP capture.

[0087] Additionally or alternatively, processing circuitry 50 may modify the amplitude (e.g., voltage) of ventricular pacing in response to detecting a possible loss of LBBAP or detecting septal pacing (in such a manner as to reestablish or maintain appropriate LBBAP therapy). For example, in response to determining that ventricular capture includes septal pacing, processing circuitry 50 may increase the stimulation voltage to an amplitude that produces LBBAP capture. For example, if a transition from LBBAP to septal pacing occurs when the stimulation voltage is decreased from 1.75V to 1.5V, processing circuitry 50 may increase the pacing voltage within appropriate limits (e.g., to a stimulation voltage of 1.75V or greater).

[0088] In various situations, particularly at low pacing amplitudes, IMD 10 may not sense pacing pulses within a cardiac cycle due to loss of capture. In the event of a loss of capture, the capture sensing time (t c ) may be relatively large. For example, t c is 223ms, which is consistent with the t of 105ms of the cardiac cycle 122A. c As used herein, t c It can be referred to as the voltage delivered from the stimulus (V p ) to the far-field EGM from V within a sampling window (having a length of, for example, 250 ms). p In some examples, t c It can be referred to as the voltage delivered from the stimulus (V p ) to a negative deflection having an amplitude equal to or greater than a threshold value (such as 0.5 mV, 1 mV, etc.). In some examples, the capture sensing time in response to the cardiac cycle is equal to or greater than the capture sensing time threshold (e.g., t c greater than 150 ms), processing circuitry 50 may determine that loss of capture has occurred and that LBBAP or interval pacing is uncertain (e.g., by Figure 5 The "Algo" value 0 in the .

[0089] Although described herein as being performed by processing circuitry 50 of IMD 10 for cardiac EGM 120, some or all of the techniques may be performed by processing circuitry of another device (e.g., processing circuitry 80, processing circuitry 98, etc.) for any cardiac EGM in which one or more heartbeats may be identified.

[0090] Figure 6 is a conceptual diagram of the depolarization waveform 124. Figure 6 As shown, IMD 10 delivers a pacing voltage (Vpacing) to the patient at a first time 126. At a second time 128, depolarization waveform 124 reaches a maximum amplitude. Processing circuit 50 may determine a maximum ventricular amplitude time 130 (e.g., tpacing) by subtracting second time 128 from first time 126. 最大 Processing circuit 50 may use the above-described area center equation to determine the area center 132 (eg, X ) under segment 125 of depolarization waveform 124. a ). Processing circuitry 50 may then determine a ventricular activation time metric (e.g., t4) based on maximum ventricular amplitude time 130 and area center 132 of depolarization waveform 124. For example, processing circuitry 50 may determine a ventricular activation time metric (e.g., t4) by subtracting area center 132 (e.g., t4) from maximum ventricular amplitude time 130. 最大 -X a ) to determine a ventricular activation time measure (e.g., t4).

[0091] Figure 7 is a flow chart illustrating example operations for detecting a transition between LBBAP and septal pacing for ventricular capture in accordance with the techniques of the present disclosure. Figure 7 The exemplary operations of are described as being performed by processing circuitry 50 of IMD 10 and based on Figure 5 selected features of the cardiac EGM 120, but the observed pacing can occur at a single pacing voltage and does not experience Figure 5 Additionally, in other examples, some or all of the example operations may be performed for any cardiac EGM by processing circuitry of another device.

[0092] The IMD 10 may deliver cardiac pacing pulses, e.g., to the ventricular septum and intended to provide LBBAP (700). The IMD 10 may capture segments of the post-pacing EGM (e.g., within an analysis window 123) and then determine any EGM changes on a beat-by-beat basis (702). The processing circuitry 50 may determine a ventricular activation time metric based on the cardiac EGM 120, e.g., within the analysis window 123 (704). In general, relatively low ventricular activation time metric values ​​(e.g., relatively low t4 and / or T4R values) may indicate that ventricular capture includes LBBAP, and relatively high ventricular activation time metric values ​​may indicate that ventricular capture includes septal pacing (rather than LBBAP).

[0093] Processing circuitry 50 may determine whether a ventricular activation time metric (e.g., t4 and / or T4R) is greater than a ventricular activation time threshold (706). In response to determining that the t4 and / or T4R values ​​are above the corresponding ventricular activation time threshold ("yes" at 706), processing circuitry 50 may output a report that ventricular capture includes septal pacing (708). In some examples, processing circuitry 50 may modify (e.g., increase) the stimulation voltage in response to the ventricular capture including septal pacing (710). On the other hand, in response to determining that the t4 and / or T4R values ​​are below the corresponding ventricular activation time threshold ("no" at 706), processing circuitry 50 may output a report that ventricular capture includes LBBAP (712).

[0094] Figure 7 The exemplary techniques of may be implemented as part of any known cardiac pacing threshold determination technique, which may occur during implantation of IMD 10 or during a clinical visit as directed by external device 12, or may occur automatically on a scheduled or periodic basis. Although described as being performed for a single heartbeat or cycle after delivery of a ventricular pacing pulse intended to provide LBBAP, Figure 7 The exemplary technique of can be performed multiple times at a given cardiac pacing amplitude, and then the processing circuit determines whether the pacing amplitude produces LBBAP or interval pacing. In some examples, Figure 7 The exemplary technique may be performed during delivery of pacing at multiple amplitudes to search for an amplitude that is captured by transitions between LBBAP and interval pacing. The processing circuit may report the transition amplitude (e.g., amplitude), and / or determine the amplitude of a subsequent pacing operation, for example by adding a safety margin to the determined transition amplitude.

[0095] Figure 8 is a flow chart illustrating example operations for detecting a transition between LBBAP and septal pacing for ventricular capture in accordance with the techniques of the present disclosure. Figure 8 The exemplary operations of are described as being performed by processing circuitry 50 of IMD 10 and based on Figure 5selected features of the cardiac EGM 120, but the observed pacing can occur at a single pacing voltage and does not experience Figure 5 Additionally, in other examples, some or all of the example operations may be performed for any cardiac EGM by processing circuitry of another device.

[0096] The IMD 10 may deliver cardiac pacing pulses, e.g., to the ventricular septum and intended to provide LBBAP (800). The IMD 10 may capture segments of the post-pacing EGM (e.g., within an analysis window 123) and then determine any EGM changes on a beat-by-beat basis (802). The processing circuit 50 may determine a ventricular activation time metric based on the cardiac EGM 120, e.g., within the analysis window 123 (804). In general, relatively low ventricular activation time metric values ​​(e.g., relatively low t4 and / or T4R values) may indicate that ventricular capture includes LBBAP, and relatively high ventricular activation time metric values ​​may indicate that ventricular capture includes septal pacing (rather than LBBAP).

[0097] In some examples, processing circuitry 50 may determine a morphology metric (806). Processing circuitry 50 may determine the morphology metric by comparing EGM 120 within analysis window 123 with a template waveform representing a confirmed LBBAP. Based on the comparison, processing circuitry 50 may output the morphology metric. In some examples, processing circuitry 50 may use a wavelet transform algorithm to compare coefficients of cardiac cycle 122 with coefficients of the template waveform to calculate a matching metric value for cardiac cycle 122.

[0098] Processing circuit 50 may determine whether the morphology metric satisfies the morphology condition (808). For example, when the matching metric value is equal to or greater than a threshold value (e.g., 70), the morphology metric may satisfy the morphology condition. The threshold value may be an absolute value, a percentage, etc. Satisfying the morphology condition may indicate a higher likelihood of LBBAP.

[0099] In response to determining that the morphology metric satisfies the morphology condition ("YES" at 808), processing circuitry 50 may determine whether the ventricular activation time metric value is greater than a first ventricular activation time threshold (810). In response to determining that the t4 and / or T4R values ​​are above the corresponding first ventricular activation time threshold ("YES" at 810), processing circuitry 50 may output a report that ventricular capture includes septal pacing (812). In some examples, processing circuitry 50 may modify (e.g., increase) the stimulation voltage in response to the ventricular capture including septal pacing (814). On the other hand, in response to determining that the t4 and / or T4R values ​​are below the corresponding first ventricular activation time threshold ("NO" at 810), processing circuitry 50 may output a report that ventricular capture includes LBBAP (816).

[0100] In response to determining that the morphology metric does not satisfy the morphology condition ("NO" at 808), e.g., indicating a possible deviation from expected therapeutic pacing, the processing circuit 50 may determine whether the ventricular excitation time metric value is greater than a second ventricular excitation time threshold (818). Because the morphology metric indicates a possible deviation from expected therapeutic pacing, the first ventricular excitation time threshold may be greater than the second ventricular excitation time threshold. Therefore, the second ventricular excitation time threshold is set to a level that provides more monitoring. An exemplary second ventricular excitation time threshold may include a t4 value of 200 ms and / or a T4R value of 1.1, but may be other values. In response to determining that the ventricular excitation time metric value is greater than the second ventricular excitation time threshold ("YES" at 818), the processing circuit 50 may output an indication indicating that ventricular capture includes septal pacing (812). If the ventricular capture previously included LBBAP, the processing circuit 50 may output an indication indicating that the ventricular capture is transitioning between LBBAP and septal pacing. In some examples, in response to determining that ventricular capture includes septal pacing, processing circuitry 50 may modify the amplitude of the pacing voltage to cause a transition from septal pacing to LBBAP (e.g., by increasing the pacing voltage by a predetermined amount or to the last pacing voltage consistent with ventricular capture including LBBAP, or by running a threshold detection analysis ( Figure 5 ) to determine a new pacing voltage including LBBAP)(814).

[0101] In response to determining that the ventricular activation time metric is not greater than the second ventricular activation time threshold ("NO" at 818), processing circuitry 50 may output an indication indicating that ventricular capture includes LBBAP or the metric result (816). If ventricular capture previously included LBBAP, processing circuitry 50 may output an indication indicating that ventricular capture did not transition between LBBAP and septal pacing.

[0102] Figure 8 The exemplary techniques of may be implemented as part of any known cardiac pacing threshold determination technique, which may occur during implantation of IMD 10 or during a clinical visit as directed by external device 12, or may occur automatically on a scheduled or periodic basis. Although described as being performed for a single heartbeat or cycle after delivery of a ventricular pacing pulse intended to provide LBBAP, Figure 8 The exemplary technique of can be performed multiple times at a given cardiac pacing amplitude, and then the processing circuit determines whether the pacing amplitude produces LBBAP or interval pacing. In some examples, Figure 8 The exemplary technique may be performed during delivery of pacing at multiple amplitudes to search for an amplitude that is captured by transitions between LBBAP and interval pacing. The processing circuit may report the transition amplitude (e.g., amplitude), and / or determine the amplitude of a subsequent pacing operation, for example by adding a safety margin to the determined transition amplitude.

[0103] The present disclosure includes various embodiments, such as the following embodiments.

[0104] Embodiment 1: A medical device system, comprising: a medical device configured to deliver ventricular pacing to a patient's heart; and a processing circuit configured to: receive electrocardiogram data of the patient sensed by the medical device during delivery of ventricular pacing; identify multiple paced heartbeats within the electrocardiogram data; for each of the multiple heartbeats: determine a ventricular excitation time metric; and determine whether ventricular capture includes left bundle branch area pacing or interval pacing based on the ventricular excitation time metric; and in response to determining that ventricular capture includes interval pacing, modify the amplitude of the ventricular pacing.

[0105] Embodiment 2: A medical device system according to embodiment 1, wherein the processing circuit is configured to determine the ventricular excitation time measure for each heart beat in the multiple heart beats by the following steps: determining the center of area under a segment of the depolarization waveform and the maximum ventricular amplitude time of the heart beat; and determining the ventricular excitation time measure for the heart beat based on the center of area and the maximum ventricular amplitude time.

[0106] Embodiment 3: The medical device system of Embodiment 2, wherein the processing circuit is configured to determine the ventricular activation time metric by subtracting the area center from the maximum ventricular amplitude time.

[0107] Embodiment 4: According to any one of embodiments 1 to 3, the processing circuit is further configured to: determine a morphology metric; and determine whether ventricular capture includes left bundle branch area pacing or interval pacing based on the morphology metric and the ventricular excitation time metric.

[0108] Embodiment 5: A medical device system according to Embodiment 4, wherein the processing circuit is configured to determine the morphology metric by the following steps: for each heartbeat in the multiple heartbeats, comparing the corresponding analysis window with a template; and determining the morphology metric based on the comparison.

[0109] Embodiment 6: The medical device system according to Embodiment 5, wherein the processing circuit is configured to compare the corresponding analysis window with the template by using a wavelet transform algorithm.

[0110] Embodiment 7: The medical device system of any one of Embodiments 4 to 6, wherein the processing circuit is configured to determine whether ventricular capture includes left bundle branch area pacing or septal pacing by determining whether the morphology metric satisfies a morphology condition.

[0111] Embodiment 8: The medical device system of Embodiment 7, wherein satisfying the morphological condition indicates a high likelihood of left bundle branch region pacing.

[0112] Embodiment 9: A medical device system according to Embodiment 7 or 8, wherein the processing circuit is further configured to: in response to determining that the morphology metric satisfies the morphology condition, determine whether the ventricular excitation time metric value is greater than a first ventricular excitation time threshold, wherein the ventricular excitation time metric value being greater than the first ventricular excitation time threshold indicates interval pacing.

[0113] Embodiment 10: A medical device system according to any one of embodiments 7 to 9, wherein the processing circuit is further configured to: in response to determining that the morphology metric does not satisfy the morphology condition, determine whether the ventricular excitation time metric value is greater than a second ventricular excitation time threshold, wherein the ventricular excitation time metric value being greater than the second ventricular excitation time threshold indicates interval pacing.

[0114] Embodiment 11: The medical device system of any one of Embodiments 1 to 10, wherein the processing circuit is configured to modify the amplitude of the ventricular pacing by increasing stimulation voltage.

[0115] Embodiment 12: The medical device system of any one of Embodiments 1 to 11, wherein the processing circuit is configured to modify the amplitude of the ventricular pacing to re-establish left bundle branch area pacing.

[0116] Embodiment 13: The medical device system of any one of Embodiments 1 to 12, wherein the processing circuit is further configured to output a report including an indication of whether the ventricular capture included left bundle branch region pacing or septal pacing.

[0117] Embodiment 14: The medical device system according to any one of Embodiments 1 to 13, wherein the medical device comprises the processing circuit.

[0118] Embodiment 15: A method, comprising: receiving by a processing circuit of a medical device system, the method comprising: determining, by the processing circuit, a ventricular excitation time measurement; and determining, by the processing circuit and based on the ventricular excitation time measurement, whether ventricular capture includes left bundle branch area pacing or interval pacing; and in response to determining that ventricular capture includes interval pacing, modifying, by the processing circuit, the amplitude of the ventricular pacing.

[0119] Example 16: A method according to Example 15, wherein determining the ventricular excitation time measure for each heart beat in the multiple heart beats comprises: determining, by the processing circuit, the center of the area under the segment of the depolarization waveform and the maximum ventricular amplitude time of the heart beat; and determining the ventricular excitation time measure for the heart beat based on the center of the area and the maximum ventricular amplitude time.

[0120] Embodiment 17: The method of embodiment 16, wherein determining the ventricular activation time metric comprises subtracting the area center from the maximum ventricular amplitude time.

[0121] Embodiment 18: According to the method described in any one of Embodiments 15 to 17, the method further includes determining, by the processing circuit, a morphology metric; and determining, by the processing circuit and based on the morphology metric and the ventricular excitation time metric, whether ventricular capture includes left bundle branch area pacing or interval pacing.

[0122] Embodiment 19: The method according to embodiment 18, wherein determining the morphology metric comprises: for each heartbeat in the multiple heartbeats, comparing the corresponding analysis window with a template; and determining the morphology metric based on the comparison.

[0123] Embodiment 20: The method according to embodiment 19, wherein comparing the corresponding analysis window with the template comprises using a wavelet transform algorithm.

[0124] Example 21: The method of any one of Examples 18 to 20, wherein determining whether ventricular capture includes left bundle branch region pacing or septal pacing includes determining whether the morphology metric satisfies a morphology condition.

[0125] Example 22: The method of Example 21, wherein satisfying the morphological condition indicates a higher likelihood of left bundle branch region pacing.

[0126] Embodiment 23: According to the method described in Embodiment 21 or 22, the method further includes: in response to determining that the morphology metric satisfies the morphology condition, determining whether the ventricular excitation time metric value is greater than a first ventricular excitation time threshold, wherein the ventricular excitation time metric value being greater than the first ventricular excitation time threshold indicates interval pacing.

[0127] Embodiment 24: According to the method described in any one of Embodiments 21 to 23, the method further comprises: in response to determining that the morphology metric does not satisfy the morphology condition, determining whether the ventricular excitation time metric value is greater than a second ventricular excitation time threshold, wherein the ventricular excitation time metric value being greater than the second ventricular excitation time threshold indicates interval pacing.

[0128] Embodiment 25: The method of any one of Embodiments 15 to 25, further comprising outputting, by the processing circuit and based on the determination of the plurality of heartbeats, a report comprising an indication of whether the ventricular capture included left bundle branch area pacing or interval pacing.

[0129] Embodiment 26: The method according to embodiment 1 further comprises gradually reducing the stimulation voltage of the ventricular pacing from an initial amplitude to perform initial capture detection.

[0130] Embodiment 27: An implantable medical device comprising: a therapy delivery circuit configured to deliver ventricular pacing to a patient's heart; a sensing circuit configured to sense electrocardiogram data of the patient during delivery of ventricular pacing; a processing circuit configured to: identify multiple heartbeats within the electrocardiogram data; for each of the multiple heartbeats: determine a ventricular excitation time metric; and based on the ventricular excitation time metric, determine whether ventricular capture includes left bundle branch area pacing or interval pacing; and in response to determining that ventricular capture includes interval pacing, modify the amplitude of the ventricular pacing.

[0131] Embodiment 28: An implantable medical device according to Embodiment 27, wherein the processing circuit is configured to determine the ventricular excitation time metric for each heartbeat in the multiple heartbeats by: determining the center of area under a segment of the depolarization waveform and the maximum ventricular amplitude time of the heartbeat; and determining the ventricular excitation time metric for the heartbeat based on the center of area and the maximum ventricular amplitude time.

[0132] Embodiment 29: The implantable medical device of Embodiment 28, wherein the processing circuit is configured to determine the ventricular activation time metric by subtracting the area center from the maximum ventricular amplitude time.

[0133] Embodiment 30: An implantable medical device according to any one of embodiments 27 to 29, wherein the processing circuit is further configured to: determine a morphology metric; and determine whether ventricular capture includes left bundle branch area pacing or interval pacing based on the morphology metric and the ventricular excitation time metric.

[0134] Embodiment 31: An implantable medical device according to Embodiment 30, wherein the processing circuit is configured to determine the morphological metric by the following steps: for each heartbeat in the multiple heartbeats, comparing the corresponding analysis window with a template; and determining the morphological metric based on the comparison.

[0135] Embodiment 32: The implantable medical device according to Embodiment 31, wherein the processing circuit is configured to compare the corresponding analysis window with the template by using a wavelet transform algorithm.

[0136] Embodiment 33: An implantable medical device according to any one of Embodiments 30 to 32, wherein the processing circuit is configured to determine whether ventricular capture includes left bundle branch area pacing or septal pacing by determining whether the morphology metric satisfies a morphology condition.

[0137] Embodiment 34: An implantable medical device according to Embodiment 33, wherein satisfying the morphological condition indicates a higher likelihood of left bundle branch region pacing.

[0138] Embodiment 35: An implantable medical device according to Embodiment 33 or 34, wherein the processing circuit is further configured to: in response to determining that the morphology metric satisfies the morphology condition, determine whether the ventricular excitation time metric value is greater than a first ventricular excitation time threshold, wherein the ventricular excitation time metric value being greater than the first ventricular excitation time threshold indicates interval pacing.

[0139] Embodiment 36: An implantable medical device according to any one of Embodiments 33 to 35, wherein the processing circuit is further configured to: in response to determining that the morphology metric does not satisfy the morphology condition, determine whether the ventricular excitation time metric value is greater than a second ventricular excitation time threshold, wherein the ventricular excitation time metric value being greater than the second ventricular excitation time threshold indicates interval pacing.

[0140] Embodiment 37: An implantable medical device according to any one of Embodiments 27 to 36, wherein the processing circuit is configured to modify the amplitude of the ventricular pacing by increasing the stimulation voltage.

[0141] Embodiment 38: An implantable medical device according to any one of Embodiments 27 to 37, wherein the processing circuit is configured to modify the amplitude of the ventricular pacing to re-establish left bundle branch area pacing.

[0142] Embodiment 39: An implantable medical device according to any one of Embodiments 27 to 38, wherein the processing circuit is further configured to output a report including an indication of whether the ventricular capture includes left bundle branch area pacing or septal pacing.

[0143] The techniques described in the present disclosure may be implemented at least in part in the form of hardware, software, firmware, or any combination thereof. For example, various aspects of these techniques may be implemented in one or more microprocessors, DSPs, ASICs, FPGAs, or any other equivalent integrated or discrete logic QRS circuits, and any combination of such components, which are embodied in an external device (such as a physician or patient programmer, simulator, or other device). The terms "processor" and "processing circuit" may generally refer to any of the aforementioned logic circuits, alone or in combination with other logic circuits, or any other equivalent circuit, alone or in combination with other digital or analog circuits.

[0144] For various aspects implemented in software, at least some of the functionality attributed to the systems and devices described in this disclosure may be embodied as instructions on a computer-readable storage medium, such as RAM, DRAM, SRAM, magnetic disk, optical disk, flash memory, or various forms of EPROM or EEPROM. The instructions may be executed to support one or more aspects of the functionality described in this disclosure.

[0145] In addition, in some aspects, the functions described herein can be set in dedicated hardware and / or software modules. 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. On the contrary, the functions associated with one or more modules or units can be performed by separate hardware or software components, or integrated in common or separate hardware or software components. In addition, these techniques can be fully implemented in one or more circuits or logic elements. The technology disclosed herein can be implemented in various devices or equipment, including an IMD, an external programmer, a combination of an IMD and an external programmer, an integrated circuit (IC) or a group of ICs and / or discrete circuits residing in an IMD and / or an external programmer.

Claims

1. A medical device system, comprising: a medical device configured to deliver ventricular pacing to a patient's heart; and A processing circuit, the processing circuit being configured to: receiving electrocardiogram data of the patient sensed by the medical device during delivery of ventricular pacing; identifying a plurality of paced heartbeats within the electrocardiogram data; For each of multiple heartbeats: Determine ventricular activation time measurements; as well as determining whether ventricular capture includes left bundle branch region pacing or septal pacing based on the ventricular activation time metric; as well as In response to determining that ventricular capture includes septal pacing, an amplitude of the ventricular pacing is modified.

2. The medical device system of claim 1 , wherein the processing circuit is configured to determine the ventricular activation time metric for each of the plurality of heartbeats by: determining a center of area under a segment of the depolarization waveform and a time of maximum ventricular amplitude for said heartbeat; and The ventricular activation time metric for the heartbeat is determined based on the area center and the maximum ventricular amplitude time.

3. The medical device system of claim 2, wherein the processing circuit is configured to determine the ventricular activation time metric by subtracting the area center from the maximum ventricular amplitude time.

4. The medical device system according to any one of claims 1 to 3, wherein the processing circuit is further configured to: determining morphological metrics; and A determination is made based on the morphology metric and the ventricular activation time metric whether ventricular capture includes left bundle branch area pacing or septal pacing.

5. The medical device system of claim 4, wherein the processing circuit is configured to determine the morphology metric by: For each heartbeat of the plurality of heartbeats, comparing the corresponding analysis window with the template; and The morphology metric is determined based on the comparison. 6 . The medical device system of claim 5 , wherein the processing circuit is configured to compare the corresponding analysis window with the template by using a wavelet transform algorithm.

7. A medical device system according to any one of claims 4 to 6, wherein the processing circuit is configured to determine whether ventricular capture includes left bundle branch area pacing or interval pacing by determining whether the morphology metric satisfies a morphology condition, wherein satisfying the morphology condition indicates a higher likelihood of left bundle branch area pacing.

8. The medical device system of claim 7, wherein the processing circuit is further configured to: In response to determining that the morphology metric satisfies the morphology condition, it is determined whether the ventricular activation time metric value is greater than a first ventricular activation time threshold, wherein the ventricular activation time metric value being greater than the first ventricular activation time threshold indicates interval pacing.

9. The medical device system according to claim 7 or 8, wherein the processing circuit is further configured to: In response to determining that the morphology metric does not satisfy the morphology condition, determining whether the ventricular activation time metric value is greater than a second ventricular activation time threshold, wherein the ventricular activation time metric value being greater than the second ventricular activation time threshold indicates interval pacing.

10. The medical device system of any one of claims 1 to 9, wherein the processing circuit is configured to modify the amplitude of the ventricular pacing by increasing stimulation voltage to re-establish left bundle branch area pacing.

11. A method comprising: receiving, by processing circuitry of a medical device system including the medical device, electrocardiogram data of a patient sensed by the medical device during delivery of ventricular pacing; identifying, by the processing circuit, a plurality of heartbeats within the electrocardiogram data; For each heartbeat in the plurality of heartbeats: determining, by the processing circuit, a ventricular activation time metric; as well as determining, by the processing circuitry and based on the ventricular activation time metric, whether ventricular capture includes left bundle branch region pacing or septal pacing; as well as In response to determining that ventricular capture includes septal pacing, an amplitude of the ventricular pacing is modified by the processing circuit.

12. The method of claim 11, wherein determining the ventricular activation time metric for each of the plurality of heartbeats comprises: determining, by the processing circuit, a center of area under a segment of the depolarization waveform and a time of maximum ventricular amplitude of the heartbeat; as well as The ventricular activation time metric for the heartbeat is determined based on the area center and the maximum ventricular amplitude time.

13. The method of claim 12, wherein determining the ventricular activation time metric comprises subtracting the area center from the maximum ventricular amplitude time.

14. The method according to any one of claims 11 to 13, further comprising: determining, by the processing circuit, a morphology metric; as well as A determination is made, by the processing circuit and based on the morphology metric and the ventricular activation time metric, whether ventricular capture includes left bundle branch area pacing or septal pacing.

15. The method of claim 14, wherein determining the morphology metric comprises: For each heartbeat of the plurality of heartbeats, comparing the corresponding analysis window with the template; as well as The morphology metric is determined based on the comparison.

16. The method of claim 15, wherein comparing the corresponding analysis window to the template comprises using a wavelet transform algorithm.

17. The method of any one of claims 14 to 16, wherein determining whether ventricular capture includes left bundle branch area pacing or septal pacing comprises determining whether the morphology metric satisfies a morphology condition, wherein satisfying the morphology condition indicates a high likelihood of left bundle branch area pacing.

18. The method according to claim 17, further comprising: In response to determining that the morphology metric satisfies the morphology condition, it is determined whether the ventricular activation time metric value is greater than a first ventricular activation time threshold, wherein the ventricular activation time metric value being greater than the first ventricular activation time threshold indicates interval pacing.

19. The method according to any one of claims 17 to 18, further comprising: In response to determining that the morphology metric does not satisfy the morphology condition, determining whether the ventricular activation time metric value is greater than a second ventricular activation time threshold, wherein the ventricular activation time metric value being greater than the second ventricular activation time threshold indicates interval pacing.

20. The method of any one of claims 11 to 19, further comprising outputting, by the processing circuit and based on the determination of the plurality of heartbeats, a report including an indication of whether ventricular capture included left bundle branch region pacing or septal pacing.

21. The method of claim 11, further comprising gradually decreasing a stimulation voltage of the ventricular pacing from an initial amplitude to perform an initial capture detection.

22. An implantable medical device, comprising: a therapy delivery circuit configured to deliver ventricular pacing to a heart of a patient; sensing circuitry configured to sense electrocardiogram data of the patient during delivery of ventricular pacing; A processing circuit, the processing circuit being configured to: identifying a plurality of heartbeats within the electrocardiogram data; For each heartbeat in the plurality of heartbeats: Determine ventricular activation time measurements; as well as determining whether ventricular capture includes left bundle branch region pacing or septal pacing based on the ventricular activation time metric; as well as In response to determining that ventricular capture includes septal pacing, an amplitude of the ventricular pacing is modified.

23. The implantable medical device of claim 22, wherein the processing circuit is configured to determine the ventricular activation time metric for each of the plurality of heartbeats by: determining a center of area under a segment of the depolarization waveform and a time of maximum ventricular amplitude for said heartbeat; and The ventricular activation time metric for the heartbeat is determined based on the area center and the maximum ventricular amplitude time.

24. The implantable medical device of claim 23, wherein the processing circuit is configured to determine the ventricular activation time metric by subtracting the area center from the maximum ventricular amplitude time.

25. The implantable medical device according to any one of claims 22 to 24, wherein the processing circuit is further configured to: determining morphological metrics; and A determination is made based on the morphology metric and the ventricular activation time metric whether ventricular capture includes left bundle branch area pacing or septal pacing.

26. The implantable medical device of claim 25, wherein the processing circuit is configured to determine the morphology metric by: For each heartbeat of the plurality of heartbeats, comparing the corresponding analysis window with the template; and The morphology metric is determined based on the comparison.

27. The implantable medical device of claim 26, wherein the processing circuit is configured to compare the corresponding analysis window with the template by using a wavelet transform algorithm.

28. An implantable medical device according to any one of claims 25 to 27, wherein the processing circuit is configured to determine whether ventricular capture includes left bundle branch area pacing or interval pacing by determining whether the morphology metric satisfies a morphology condition, wherein satisfying the morphology condition indicates a higher likelihood of left bundle branch area pacing.

29. The implantable medical device of claim 28, wherein the processing circuit is further configured to: In response to determining that the morphology metric satisfies the morphology condition, it is determined whether the ventricular activation time metric value is greater than a first ventricular activation time threshold, wherein the ventricular activation time metric value being greater than the first ventricular activation time threshold indicates interval pacing.

30. The implantable medical device of claim 28 or 29, wherein the processing circuit is further configured to: In response to determining that the morphology metric does not satisfy the morphology condition, determining whether the ventricular activation time metric value is greater than a second ventricular activation time threshold, wherein the ventricular activation time metric value being greater than the second ventricular activation time threshold indicates interval pacing.

31. An implantable medical device according to any one of claims 22 to 30, wherein the processing circuit is configured to modify the amplitude of the ventricular pacing by increasing stimulation voltage to re-establish left bundle branch area pacing.

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