Device for monitoring conductive system pacing

Abstract

A medical device system configured to obtain a cardiac electrical signal seizure sensed during a conduction system capture management test, and determine capture test data from the cardiac electrical signal seizure. The medical device system may be configured to: detect an alarm condition of the conductive system capture management test, the alarm condition indicating a change in the capture test data compared to a previous conductive system capture management test; and generating an output in response to detecting the alarm condition. The generated output may be stored in a memory of the medical device system. The medical device system may display data in a user interface based on the generated output.

Description

Technical Field

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 381,268, filed Oct. 27, 2022, the entire content of which is incorporated herein by reference.

[0002] This disclosure relates to medical device systems and methods for monitoring the pacing of a patient's cardiac conduction system. Background Art

[0003] During normal sinus rhythm (NSR), the heartbeat is regulated by electrical signals generated by the sinoatrial (SA) node located in the wall of the right atrium. Each depolarization signal generated by the SA node spreads through the atrium, causing depolarization and contraction of that atrium, and reaches the atrioventricular (AV) node. The AV node propagates the depolarization signal through the His bundle (or "bundle of His") of the atrioventricular septum, and thereafter reaches the bundle branches and Purkinje muscle fibers of the right and left ventricles in response, which is sometimes referred to as the "His-Purkinje conduction system".

[0004] Patients with conduction system abnormalities (e.g., poor AV node conduction, poor SA node function, or other conduction abnormalities) may receive a pacemaker to restore a more normal heart rhythm and cardiac chamber synchronization. Ventricular pacing may be performed to maintain the ventricular rate in patients with atrioventricular conduction abnormalities. A single-chamber ventricular pacemaker may be coupled to a transvenous ventricular lead carrying an electrode placed in the right ventricle (RV) (e.g., at the right ventricular apex). The pacemaker itself is typically implanted in a subcutaneous pocket, where the transvenous ventricular lead tunnels into the subcutaneous pocket. Intracardiac pacemakers have been introduced or proposed for implantation entirely within a patient's heart, thus eliminating the need for transvenous leads. An intracardiac pacemaker may provide sensing and pacing from within a chamber of a patient's heart, such as from within the right ventricle of a patient with AV block.

[0005] A dual-chamber pacemaker may be provided, which includes a transvenous atrial lead carrying an electrode placed in the right atrium and a transvenous ventricular lead carrying an electrode placed in the right ventricle via the right atrium. The dual-chamber pacemaker senses atrial electrical signals and ventricular electrical signals, and may provide both atrial pacing and ventricular pacing as needed to promote normal atrial and ventricular rhythms, and to promote AV synchronization when SA and / or AV node or other conduction abnormalities are present.

[0006] It has been found that ventricular pacing via an electrode at or near the right ventricular apex is associated with an increased risk of atrial fibrillation and heart failure. Alternative pacing sites have been studied or proposed, such as pacing of the His bundle or left bundle branch. Ventricular pacing along the His-Purkinje conduction system has been proposed to provide a more physiological form of ventricular pacing, as the pacing-induced depolarization can proceed along the native conduction system of the heart. Pacing the ventricle via the His bundle or left bundle branch, for example, allows recruitment along the native conduction system of the heart (including the bundle branches and Purkinje fibers) and is hypothesized to facilitate a more physiologically normal cardiac activation than other pacing sites, such as the ventricular apex. SUMMARY OF THE INVENTION

[0007] The techniques of the present disclosure generally relate to a medical device system for monitoring pacing of the His-Purkinje conduction system (also referred to herein as the "conduction system") of a patient's heart. Conduction system pacing (CSP) can be delivered for pacing the ventricle by placing at least one electrode along or near the His-Purkinje conduction system, and the at least one electrode can be along the His bundle or along one or both of the left bundle branch (LBB) and / or right bundle branch (RBB) or within the region of one or both of them. In various examples, a medical device system operating according to the methods disclosed herein obtains the onset of cardiac electrical signals sensed during a conduction system capture management (CM) test. The CM test can be performed by an implanted medical device that is coupled to and / or carries an electrode positioned for delivering ventricular pacing via the conduction system. During the CM test, the CSP pulse output (e.g., pacing pulse amplitude and / or pacing pulse width) can vary. One or more cardiac electrical signals (which can be electrogram (EGM) signals sensed using one or more electrodes implanted in or on the heart) can be recorded as the onset of cardiac electrical signals sensed by the implanted medical device during the CM test and transmitted to an external device (e.g., a computing device) for processing by the processing circuitry of the medical device system.

[0008] The processing circuit can be configured to analyze cardiac electrical signal episodes to determine capture test data. The various capture test data can include the number of different QRS waveform morphologies present in the cardiac electrical signal episode, the capture type classification of one or more of the QRS waveform morphologies, the capture thresholds associated with one or more of the QRS waveform morphologies, and / or the capture type classification identified in the cardiac electrical signal episode. The processing circuit can identify one or more changes in the capture test data compared to the capture test data determined in a previous CM test. The processing circuit can detect an alert condition corresponding to a change in the capture test data compared to the previous capture test data. The medical device system can generate an output based on the capture test data, which can include generating data for display in a user interface. The processing circuit can receive user input, such as a ground truth input, via the user interface to label QRS waveform morphologies according to the morphology type and / or capture type. The processing circuit can use the user input to identify changes in the capture test data compared to the CM test and detect the alert condition.

[0009] The subject matter of the following embodiments is also disclosed herein:

[0010] Embodiment 1. A medical device system, the medical device system comprising a processing circuit configured to receive a cardiac electrical signal episode sensed during a conduction system capture management test and determine capture test data from the cardiac electrical signal episode. The processing circuit can compare the capture test data with previous capture test data determined from a previous conduction system capture management test, and generate an output based on the comparison of the capture test data with the previous capture test data; and a memory configured to store the output.

[0011] Embodiment 2. The medical device system according to Embodiment 1, wherein the processing circuit is further configured to detect an alert condition corresponding to a change in the capture test data compared to the previous capture test data. According to the medical device system of Embodiment 1, the medical device system may further include a display unit in communication with the processing circuit. The display unit can receive the output generated by the processing circuit to display data in the user interface based on the generated output and the alert condition.

[0012] Embodiment 3. The medical device system according to any one of Embodiments 1 to 2, wherein the processing circuit is configured to determine the capture test data by identifying the number of different QRS waveform morphologies in the cardiac electrical signal episode.

[0013] Example 4. The medical device system according to Example 3, wherein the processing circuit is further configured to detect an alert condition by determining that the number of different QRS waveform morphologies in the cardiac electrical signal episode is different from the previous number of QRS waveform morphologies identified in the previous cardiac electrical signal episode sensed during the previous conduction system capture management test.

[0014] Example 5. The medical device system according to any one of Examples 3 to 4, wherein the processing circuit is further configured to determine the capture test data by determining a capture threshold for one or more of the different QRS morphologies identified in the cardiac electrical signal episode.

[0015] Example 6. The medical device system according to Example 5, wherein the processing circuit is further configured to detect an alert condition by determining that the capture threshold determined for at least one of the QRS morphologies identified in the cardiac electrical signal episode is different from the previously determined capture threshold determined for the corresponding QRS morphology identified in the previous cardiac electrical signal episode sensed during the previous capture management test.

[0016] Example 7. The medical device system according to any one of Examples 1 to 6, wherein the processing circuit is further configured to determine the capture test data by classifying at least one QRS waveform in the cardiac electrical signal episode according to a capture type.

[0017] Example 8. The medical device system according to any one of Examples 1 to 7, wherein the processing circuit is further configured to determine the capture test data by classifying a plurality of QRS waveforms in the cardiac electrical signal episode according to a plurality of capture types.

[0018] Example 9. The medical device system according to Example 8, wherein the processing circuit is further configured to determine a capture threshold for one or more of the classified capture types among the plurality of capture types of the cardiac electrical signal episode.

[0019] Example 10. The medical device system according to Example 9, wherein the processing circuit is further configured to detect the alert condition by determining a change in the capture threshold determined for at least one of the classified capture types compared to the previous capture threshold determined for the at least one of the classified capture types in the previous conduction system capture management test.

[0020] Example 11. The medical device according to any one of Examples 8 to 10, wherein the processing circuit is further configured to determine an alert condition by determining that a classified capture type among the plurality of capture types occurs under a pacing pulse output among the plurality of pacing pulse outputs of the conduction system capture management test and that the classified capture type among the plurality of capture types does not occur under the pacing pulse output of the previous conduction system capture management test.

[0021] Example 12. The medical device system according to any one of Examples 1 to 11, wherein the processing circuit is further configured to receive a user input via the user interface, the user input annotating at least one QRS waveform of the onset of the cardiac electrical signal according to at least one of a morphology type or a capture type.

[0022] Example 13. The medical device system according to Example 12, wherein the processing circuit is further configured to detect an alert condition based on the capture test data determined from the onset of the cardiac electrical signal and the user input.

[0023] Example 14. The medical device system according to any one of Examples 12 to 13, wherein the processing circuit is further configured to adjust the capture test data determined from the onset of the cardiac electrical signal in response to receiving the user input.

[0024] Example 15. The medical device system according to Example 14, wherein the processing circuit is further configured to adjust the determination of the capture test data by adjusting a criterion for detecting a morphological change by applying to the QRS morphology of the onset of the cardiac electrical signal.

[0025] Example 16. The medical device system according to any one of Examples 14 to 15, wherein the processing circuit is further configured to adjust the determination of the capture test data by adjusting a criterion for detecting a conduction system capture type by applying to the QRS morphology of the onset of the cardiac electrical signal.

[0026] Example 17. The medical device system according to any one of Examples 1 to 16, wherein the processing circuit is further configured to determine the capture test data by classifying each post-pacing waveform among the plurality of post-pacing waveforms of the onset of the cardiac electrical signal according to a capture type selected as one or more of the following: selective conduction system capture, non-selective conduction system capture, ventricular myocardial capture only without capture of the conduction system, left bundle branch capture, partial left bundle branch capture, right bundle branch capture, partial bundle branch capture, complete His bundle capture, partial His bundle capture, or capture loss.

[0027] Example 18. The medical device system according to any one of Examples 1 to 17, the medical device system further comprising a communication circuit configured to receive cardiac electrical signal episodes transmitted from an implantable medical device, the cardiac electrical signal episodes comprising at least one electrocardiogram signal.

[0028] Example 19. A method comprising receiving, by a processing circuit of a medical device system, cardiac electrical signal episodes sensed during a conduction system capture management test and determining capture test data from the cardiac electrical signal episodes. The method may include comparing the capture test data with previous capture test data determined from a previous conduction system capture management test and generating an output based on the comparison of the capture test data with the previous capture test data. The method may include storing the output in a memory.

[0029] Example 20. The method according to Example 19, the method further comprising detecting an alert condition of the conduction system capture management test, the alert condition corresponding to a change in the capture test data compared to the previous capture test data; and displaying data in a user interface based on the generated output and the alert condition.

[0030] Example 21. The method according to any one of Examples 19 to 20, the method further comprising determining the capture test data by identifying the number of different QRS waveform morphologies in the cardiac electrical signal episodes.

[0031] Example 22. The method according to Example 21, the method further comprising detecting the alert condition by determining that the number of different QRS waveform morphologies in the cardiac electrical signal episodes is different from the previous number of QRS waveform morphologies identified in previous cardiac electrical signal episodes sensed during the previous conduction system capture management test.

[0032] Example 23. The method according to any one of Examples 21 to 22, the method further comprising determining the capture test data by determining a capture threshold for one or more of the different QRS morphologies identified in the cardiac electrical signal episodes.

[0033] Example 24. The method according to Example 23, the method further comprising detecting an alert condition by determining that the capture threshold determined for at least one of the QRS morphologies identified in the cardiac electrical signal episodes is different from the previously determined capture threshold for the corresponding QRS morphology identified in the previous cardiac electrical signal episodes sensed during the previous capture management test.

[0034] Example 25. The method according to any one of Examples 19 to 24, the method further comprising determining the capture test data by classifying at least one QRS complex in the cardiac electrical signal episode according to a capture type.

[0035] Example 26. The method according to any one of Examples 19 to 25, the method further comprising determining the capture test data by classifying a plurality of QRS complexes in the cardiac electrical signal episode according to a plurality of capture types.

[0036] Example 27. The method according to Example 26, the method further comprising determining a capture threshold for one or more of the classified capture types among the plurality of capture types of the cardiac electrical signal episode.

[0037] Example 28. The method according to Example 27, the method further comprising detecting an alert condition by determining a change in the capture threshold determined for at least one of the classified capture types compared to a previous capture threshold determined for the at least one of the classified capture types in the previous conduction system capture management test.

[0038] Example 29. The method according to any one of Examples 26 to 28, the method further comprising delivering conduction system pacing pulses at a plurality of pacing pulse outputs during the conduction system capture management test and during the previous conduction system capture management test. The method may further comprise determining an alert condition by determining that the classified capture type among the plurality of capture types occurs under a pacing pulse output of the plurality of pacing pulse outputs of the conduction system capture management test and that the classified capture type among the plurality of capture types does not occur under the pacing pulse output of the plurality of pacing pulse outputs of the previous conduction system capture management test.

[0039] Example 30. The method according to any one of Examples 20 to 29, the method further comprising receiving user input via the user interface, the user input annotating at least one QRS complex of the cardiac electrical signal episode according to at least one of a morphology type or a capture type.

[0040] Example 31. The method according to Example 30, the method further comprising detecting an alert condition based on the capture test data determined from the cardiac electrical signal episode and the user input.

[0041] Example 32. The method according to any one of Examples 30 to 31, the method further comprising adjusting the capture test data determined from the cardiac electrical signal episode by the processing circuit in response to receiving the user input.

[0042] Example 33. The method according to Example 32 further includes adjusting the determination of the capture test data by adjusting the criteria for detecting morphological changes by applying the QRS morphology of the cardiac electrical signal episode.

[0043] Example 34. The method according to any one of Examples 32 to 33 further includes adjusting the determination of the capture test data by adjusting the criteria for applying the QRS morphology of the cardiac electrical signal episode to detect the type of conduction system capture.

[0044] Example 35. The method according to any one of Examples 19 to 34 further includes determining the capture test data by classifying each post-pacing waveform of a plurality of post-pacing waveforms of the cardiac electrical signal episode according to the type of capture of one or more of the following: selective conduction system capture, non-selective conduction system capture, ventricular myocardial capture only without conduction system capture, left bundle branch capture, partial left bundle branch capture, right bundle branch capture, partial bundle branch capture, complete His bundle capture, partial His bundle capture, or capture loss.

[0045] Example 36. The method according to any one of Examples 19 to 35 further includes receiving a cardiac electrical signal episode transmitted from an implantable medical device, the cardiac electrical signal episode including at least one electrocardiogram signal.

[0046] Example 37. A non-transitory computer-readable medium storing instructions that, when executed by a processing circuit of a medical device system, cause the system to: receive a cardiac electrical signal episode sensed during a conduction system capture management test; determine capture test data from the cardiac electrical signal episode; compare the capture test data with previous capture test data determined from a previous conduction system capture management test and generate the output based on the comparison of the capture test data with the previous capture test data; and store the output in a memory of the medical device system.

[0047] Example 38. The non-transitory computer-readable medium according to Example 37, wherein the instructions further cause the medical device system to: detect an alarm condition corresponding to a change in the capture test data compared to the previous capture test data; and display data in a user interface based on the generated output and the alarm condition.

[0048] Details of one or more aspects of the present disclosure are set forth in the following drawings and description. Other features, objects, and advantages of the techniques described in the present disclosure will be apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1Conceptual diagram of a medical device system capable of delivering conduction system pacing (CSP) and sensing and analyzing cardiac electrical signals to determine capture test data, according to some examples.

[0050] Figure 2 Conceptual diagram of an implantable medical device (IMD) connected to pacing and sensing leads to pace a patient's heart and sense cardiac electrical signals.

[0051] Figure 3 Conceptual diagram of an IMD coupled to a lead that is advanced to an alternative location within the heart to deliver CSP and sense cardiac electrical signals.

[0052] Figure 4 Conceptual diagram of a leadless pacemaker positioned within the heart for providing CSP, according to another example.

[0053] Figure 5 Is Figure 4 Conceptual diagram of a leadless pacemaker that is shown implanted in an alternative location for CSP.

[0054] Figure 6 Conceptual diagram of the circuitry of an IMD configured to sense cardiac electrical signals and perform CSP, according to some examples.

[0055] Figure 7 Flowchart of a method that can be performed by an IMD included in a medical device system, according to some examples.

[0056] Figure 8 Conceptual diagram of a graphical user interface (GUI) that can be displayed to a user on an external device or a computing device to enable the user to program CM control parameters, according to some examples.

[0057] Figure 9 Is according to some examples of a method that can be performed by a processing circuit of a medical device system (e.g., Figure 1 of the medical device system) for detecting an alert condition from cardiac electrical signal episodes recorded during a CM test.

[0058] Figure 10 Is according to another example of a method that can be performed by a processing circuit of a medical device system (e.g., Figure 1 of the medical device system) for detecting and responding to changes in capture test data.

[0059] Figure 11 Flowchart of a method for detecting an alert condition from cardiac electrical signal episodes by a processing circuit of a medical device system, according to some examples.

[0060] Figure 12A flowchart of a method according to another example for analyzing cardiac electrical signal episodes sensed during a CM test to detect a change in captured test data by a processing circuit of a medical device system.

[0061] Figure 13 A diagram of a GUI that can be generated by a medical device processing circuit according to some examples for displaying CM test data to a user. Detailed Description

[0062] A medical device system for obtaining, processing, and analyzing cardiac electrical signal episodes sensed during a CM test to monitor changes in capture during CSP is described herein. Cardiac electrical signal episodes that may include one or more cardiac electrical signals sensed during a CM test and / or data derived therefrom may be transmitted from an IMD for receipt by a processing circuit of the medical device system. The medical device system processing circuit may be configured to detect a change in a cardiac electrical signal episode compared to a previous cardiac electrical signal episode sensed during a previous CM test. For example, the processing circuit may determine captured test data from the cardiac electrical signal episode for detecting a change in the captured test data compared to the previous CM test. The processing circuit may generate an output based on the captured test data for display in a GUI. The generated output may be stored in a memory of the medical device system and may be used to generate a display in a user interface based on the output. In some examples, an alert condition may be detected from the captured test data, for example, based on a comparison with previous captured test data determined from a previous CM test.

[0063] As used herein, the term "conduction system pacing" (CSP) refers to the delivery of one or more pacing pulses generated for delivery near a portion of the His-Purkinje conduction system of the heart. CSP pulses may or may not capture the conduction system, depending on the cathode and anode positions of the CSP electrode vector relative to the conduction system pacing site, the energy of the delivered pacing pulses, and other factors. Complete or partial His bundle capture, complete or partial LBB capture, and / or complete or partial RBB capture are non-limiting examples of CSP capture types. When a CSP pulse completely or partially captures the conduction system at the pacing site without capturing the ventricular myocardium, the complete or partial capture by the CSP pulse can be selective CSP capture. Capture of at least a portion of the conduction system is achieved when the pacing pulse energy delivered as a CSP pulse causes depolarization of the tissue of the conduction system. The pacing-induced depolarization that occurs at the CSP site can propagate along the conduction system and further propagate to the ventricular myocardium to cause depolarization of the ventricular myocardium and subsequent coordinated ventricular contraction. Non-selective CSP capture can occur when the CSP pulse energy is greater than both the conduction system pacing capture threshold and the ventricular myocardium pacing capture threshold. Non-selective CSP capture by the CSP pulse causes depolarization of both a portion of the conduction system and the ventricular myocardium. Only ventricular myocardium (VMO) capture can occur when the ventricular myocardium is captured (causing pacing-induced depolarization of the ventricular myocardium) without capturing any portion of the conduction system. The CSP pulse may not capture any portion of the conduction system, resulting in complete loss of capture (no pacing-induced depolarization of the conduction system or ventricular myocardium).

[0064] The medical device systems and techniques disclosed herein provide various improvements to medical device systems configured to generate and display various parameters determined from one or more cardiac electrical signals representative of cardiac electrical activity that a user may rely on when monitoring and evaluating the effectiveness of CSP. The techniques disclosed herein improve the functionality of medical device systems in providing a visual representation of CSP data that can be used to monitor CSP pulse capture.

[0065] Accordingly, the techniques disclosed herein provide improvements in the computer-related fields of cardiac monitoring and cardiac therapy delivery. By providing a medical device system capable of processing and analyzing cardiac electrical signals and displaying data in a GUI in accordance with the techniques herein, the complexity and likelihood of human error in achieving capture of at least a portion of the conduction system or selecting CSP parameters based on a desired type of capture are reduced. Managing CSP capture of a patient using the techniques disclosed herein can improve or optimize the clinical benefits of CSP by reducing the burden on a clinician to identify changes in CSP capture that may occur in a patient over time and by simplifying the process of identifying changes in capture test data. The techniques disclosed herein can enable CSP to be delivered to a patient using techniques that facilitate maintaining capture of the conduction system in a manner that is simplified, flexible, and patient-specific for a managing clinician. The techniques disclosed herein can enable selection and programming of CM test control parameters and CSP pulse parameters for achieving capture of the conduction system and the associated clinical benefits of CSP with a high degree of confidence.

[0066] Figure 1 is a conceptual diagram of a medical device system 10 capable of delivering CSP and sensing and analyzing cardiac electrical signals to determine capture test data. The system 10 can include an IMD 14 coupled to at least one cardiac pacing and sensing lead 18 that carries one or more electrodes 32 for sensing cardiac electrical signals and delivering CSP. In Figure 1 , the cardiac pacing lead 18 is shown being advanced within a patient's heart 8 for positioning a pacing electrode 32 at a CSP site, such as a CSP site within the ventricular septum in the region of the His bundle, LBB, or RBB. However, it should be understood that a pacing electrode carried by a lead coupled to an IMD or by the housing of a leadless IMD can be positioned at any desired CSP site, and additional examples of IMD and CSP lead and / or electrode configurations are provided below.

[0067] System 10 includes an external device 50 that may be configured to communicate bidirectionally with the IMD 14, for example, via a wireless communication link 62. The external device 50 may receive data related to CSP capture from the IMD 14. CSP capture data may include cardiac electrical signal episodes, which may include one or more cardiac electrical signals sensed from corresponding sensing electrode vectors. The cardiac electrical signal episode or portions thereof may be displayed by the external device 50, transmitted to another computing device 70, and / or processed and analyzed by the external device 50 to detect changes in CSP capture. The CSP capture data received by the external device 50 from the IMD 14 may additionally or alternatively include parameters, metrics, or other data determined by processing circuitry included in the IMD 14 and transmitted to the external device 50. As described further below, the CSP capture data may include one or more QRS waveforms representing different QRS morphologies sensed during a CM test, one or more capture thresholds, and / or one or more morphology metrics determined from cardiac electrical signals sensed by the IMD 14. The CSP capture data may be obtained by the IMD 14 from one or more cardiac signals sensed during a CM test.

[0068] The external device 50 may be embodied as a patient monitor, programmer, or pacing system analyzer used in a hospital, clinic, or physician's office to acquire and analyze CSP capture data, such as cardiac electrical signal episodes sensed during a CM test. The external device 50 may be a patient monitor located in the patient's home or other location for obtaining data from the IMD 14. The external device 50 may be a bedside or desktop device or a handheld device, and may be a personal device such as a smart phone, tablet computer, or other electronic device capable of wirelessly receiving data from the IMD 14. In some examples, the external device 50 may be a portable or home patient monitor included in a remote patient monitoring system (such as the CARELINK TM monitoring system available from Medtronic, Inc., Dublin, Ireland).

[0069] In some examples, the external device 50 may include an electrode / lead interface 51 for receiving inputs from skin or surface electrocardiogram (ECG) electrodes (conceptually shown as ECG electrodes 40, 42, 44, and 46). In some examples, the ECG signals may be analyzed by the processing circuitry of the medical device system 10 in combination with the CSP capture data received from the IMD 14 to detect changes in CSP capture in accordance with the techniques disclosed herein.

[0070] The external device 50 may include a processor 52, a memory 53, a display unit 54, a user interface unit 56, a telemetry unit 58, and a power source 61. The power source 61 is coupled to the various units of the external device 50 to supply power to the circuits and components of the external device 50 as needed. The power source 61 may include one or more rechargeable or non-rechargeable batteries, or may be coupled to an external power source, such as plugged into an electrical outlet. In some examples, the external device 50 may optionally include a pulse generator 60, such as when the external device 50 is a pacing system analyzer. The processor 52 may control the pulse generator 60 (when included) to generate pacing pulses for delivery as CSP pulses, for example, in some examples, delivered via the lead 18 prior to connection to the IMD 14, for testing or verifying the implant site and acceptable CSP capture thresholds.

[0071] The processor 52 may be coupled to the other components and units of the external device 50, for example, via a data bus 59, to control the functions attributed to the external device 50 herein. For example, the processor 52 may pass ECG signals, CSP capture data received from the IMD 14, and / or data derived therefrom to the display unit 54 to display the data in a GUI and / or to the telemetry unit 58 for transmission to a computing device 70. The external device telemetry unit 58 may be coupled to a communication network / cloud 75 to receive data and transmit the data to the computing device 70, which may be a personal computer, a personal mobile device, or other computing device at a location remote from the patient, to enable remote monitoring of CSP capture data obtained from the IMD 14 by a clinician or other user.

[0072] The external device processor 52 executes instructions stored in the memory 53. The processor 52 may include any one or more of the following: 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, the processor 52 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 functions attributed to the processor 52 herein may be embodied as software, firmware, hardware, or any combination thereof.

[0073] Memory 53 may include any volatile medium, non-volatile medium, magnetic medium, optical medium, or electrical medium, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), electrically erasable programmable ROM (EEPROM), flash memory, or any other digital or analog medium. Memory 53 may be configured to store instructions executed by processor 52 for obtaining and analyzing CSP capture data and displaying and / or transmitting CSP capture information in accordance with the techniques disclosed herein. Memory 53 may store CSP capture data or information received from IMD 14 and / or determined by processor 52 for generating a display of the CSP capture information in a GUI on display unit 54 or for transmission to computing device 70.

[0074] Display unit 54, which may include a liquid crystal display, light emitting diodes (LEDs), and / or other visual display components, may generate a display of CSP capture data and information, ECG signals, and / or EGM signals. Display unit 54 may generate a GUI including various windows, icons, user-selectable menus, etc. to facilitate user interaction with external device 50. Display unit 54 may be used as an input and / or output device using technologies including liquid crystal displays (LCDs), quantum dot displays, dot matrix displays, light emitting diode (LED) displays, organic light emitting diode (OLED) displays, cathode ray tube displays, electronic ink, or monochrome, color, or any other type of display capable of generating tactile, audio, and / or visual output. In some examples, display unit 54 is a presence-sensitive display that can be used as a user interface device and operates as one or more input devices and one or more output devices.

[0075] In some examples, display unit 54 may generate a visual display of one or more ECG signals, EGM signals, and / or CSP capture data and / or other capture management information based on an output generated by the processing circuitry of the medical device system. The output may be stored in memory 53 for generating a GUI including data based on the generated output and any detected alert conditions. In other examples, display unit 54 may produce an output to the user in another manner, such as via a sound card, video graphics adapter card, speakers, one or more USB interfaces, video and / or audio output interfaces, or any other type of device capable of generating audio, video, or other output. User interface unit 56 may include a data input or pointing device (such as a mouse, touch screen, keypad, etc.) to enable the user to interact with external device 50 and the GUI displayed on display unit 54, such as to initiate and terminate communication sessions, adjust the settings of display unit 54, input programmable control parameters to be programmed into IMD 14, or make other user requests.

[0076] The telemetry unit 58 may include a transceiver and an antenna configured for two-way communication with the telemetry circuitry included in the IMD 14. The telemetry unit 58 is configured to operate in conjunction with the processor 52 to send and receive data related to the IMD functions via a wireless communication link 62 with the IMD 14. A radio frequency (RF) link such as Wi-Fi, Medical Implant Communication Service (MICS), or other RF or communication frequency bandwidths or communication protocols may be used to establish the communication link 62 between the IMD 14 and the external device 50.

[0077] The IMD 14 and / or the external device 50 may be configured to communicate with one or more computing devices 70, for example, via a network / cloud 75. In some examples, the medical device system 10 may include a communication relay device 45 for sending and receiving data between the IMD 14 and the network / cloud 75. Data retrieved from the IMD 14, such as cardiac electrical signal episodes sensed during a CM test, may be analyzed by cloud-based algorithms to determine captured test data, which may be transmitted to the computing device 70 for presentation in a GUI for viewing by a clinician or other user. In some examples, the computing device 70 may take the form of a server, a personal computer, a tablet computer, or other computing devices associated with one or more healthcare providers (e.g., hospitals, medical data analysis companies, device manufacturers, etc.). The computing device 70 may collect data obtained by the IMD 14 and / or the external device 50. In some examples, this data may be anonymized and aggregated to perform large-scale analysis (e.g., using machine learning or other artificial intelligence (AI) techniques or other suitable data analysis techniques) such that captured detection algorithms are developed and improved using data collected by a large number of IMDs. The computing device 70 may transmit data to the external device 50 and / or the IMD 14. For example, updated algorithms for capture detection, CM test control parameters, updated CSP control parameters, or other data used by the IMD 14 to deliver CSP and monitor CSP capture, for example, by performing a CM test, may be provided directly or via the relay device 45 or the external device 50 to the IMD 14 via the network / cloud 75.

[0078] The computing device 70 may include a processing circuit 72, a memory 74, a communication circuit 76 (e.g., components facilitating wired or wireless communication directly or via a network / cloud 75 with other devices), and a user display / interface 78. Communication between the computing device 70 and other devices may be performed via the network 75, which may include the Internet, public and private intranets, local or extended Wi-Fi networks, cellular towers, plain old telephone systems (POTS), direct wireless communication, etc. The user display / interface 78 may include a computer monitor or display, which may be, by way of example, a touch screen, keypad, speaker, camera, keyboard, mouse, or other pointing device. CSP capture data and information may be received from the IMD 14 and / or external device 50, or derived from data received directly or indirectly from the IMD 14 and / or external device 50, for display on the user display / interface 78 of the computing device 70. A clinician or other healthcare provider may view the CSP capture data and information and select CSP control parameters, which may be remotely programmed into the IMD 14 for controlling the delivery of CSP based on an analysis of capture test data derived from one or more cardiac electrical signal episodes sensed during a CM test.

[0079] In some examples, as described below, a user may add tags or annotations to the displayed CSP capture data or information, e.g., to label QRS waveforms in an EGM or ECG signal. User-entered tags may be received by the medical device system processing circuit, which validates or classifies the QRS waveforms following CSP pulses based on morphology type and / or capture type. In some cases, user-entered tags may correct (relabel) an incorrect classification of capture type made by the processing circuit of the medical device system 10. The processing circuit of the medical device system 10 (e.g., any combination of the processing circuit 72, the processor 52, network / cloud-based computing, and / or the processing circuit included in the IMD 14) may use techniques further described below to analyze cardiac electrical signal episodes recorded during a CM test for detecting CSP capture, e.g., changes relative to a previous CM test.

[0080] Figure 2 is a conceptual diagram of the IMD 14 that is connected to pacing and sensing leads 16 and 18 to pace a patient's heart 8 and sense cardiac electrical signals. The IMD 14 is Figure 2is shown as a dual-chamber device configured to receive a right atrial lead 16 positioned in the right atrium (RA) to deliver atrial pacing pulses and sense atrial electrical signals (e.g., sense atrial P waves associated with intrinsic atrial depolarization) via electrodes 20 and 22. The lead 16 can be advanced transvenously to position the electrodes 20 and 22 within the RA. The IMD 14 can be configured to sense intrinsic atrial P waves and, in the absence of sensed P waves, deliver atrial pacing pulses using electrodes 20 and 22. The electrodes 20 and 22 can be electrically connected to the IMD 14 via electrical conductors that extend within the elongate lead body of the lead 16 to a proximal lead connector (not shown) received by the IMD connector assembly 12. The IMD 14 can be configured to provide dual-chamber sensing and pacing. For example, the IMD 14 can deliver atrial-synchronous ventricular pacing by setting an AV delay in response to each sensed P wave or delivered atrial pacing pulse and, upon expiration of the AV delay, deliver a CSP pulse via lead 18 to pace the ventricle in synchrony with the atrium.

[0081] The lead 18 can be advanced transvenously through the RA into the RV to position the pacing electrode 32 at a CSP site, such as within the ventricular septum 19. The pacing electrode 32 can be referred to as a “tip electrode” because it is carried at the distal lead tip by the CSP lead 18. As the pacing electrode 32 is advanced relatively upward within the ventricular septum 19, the pacing electrode 32 can be positioned along the lower portion of the His bundle for delivery of CSP. In other examples, the pacing electrode 32 can be advanced within the ventricular septum 19 near a bundle branch of the His-Purkinje system (e.g., at an LBB pacing site within the region of the LBB or at an RBB pacing site within the region of the RBB) for delivery of CSP.

[0082] The pacing electrode 32 can be selected as the pacing cathode electrode and used in combination with the annular electrode 34 as a return anode electrode for CSP. In some cases, the pacing pulse amplitude and pulse width (collectively referred to as “pacing pulse output”) can be selected to achieve cathode capture at the cathode electrode for capturing at least a portion of one bundle branch. In other cases, the pacing pulse amplitude and pulse width can be selected to achieve cathode and anode capture, which can concurrently capture both the LBB and RBB (with the same pacing pulse) to provide dual or bilateral bundle branch (BB) pacing using a single bipolar electrode pair. In other examples, the pacing electrode 32 or the annular electrode 34 can be selected as the cathode electrode paired with the IMD housing 15 in a unipolar pacing electrode vector. Unipolar pacing can capture at least a portion of a single BB. However, in some cases, when a unipolar pacing pulse directly captures one bundle branch, unipolar pacing can capture both the RBB and LBB while virtual current or break excitation generated by the pacing electrode can excite the other bundle branch, potentially resulting in unipolar bilateral BB pacing while capturing both the LBB and RBB.

[0083] Although lead 18 is shown as carrying a pair of pacing and sensing electrodes (i.e., pacing electrode 32 and ring electrode 34), it should be understood that in other examples, lead 18 may include multiple pacing and sensing 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., together with housing 15) for delivering CSP pulses and sensing ventricular electrical signals.

[0084] Lead 18 may also include one or more cardioversion / defibrillation (CV / DF) electrodes 35 for delivering relatively high-voltage shock therapies. CV / DF electrodes typically have a high surface area and may be elongated coil electrodes, as illustrated by coil electrode 35 on lead 18. In addition to delivering relatively low-voltage atrial and CSP pulses, IMD 14 may also be configured as an implantable cardioverter defibrillator (ICD) capable of delivering high-voltage shock therapies to terminate ventricular tachycardia or fibrillation. Coil electrode 35 may also be used in a sensing electrode vector (e.g., together with either pacing electrode 32 or ring electrode 34) to sense ventricular EGM signals, which may be transmitted to external device 50 via a communication link. Other examples of pacing lead configurations for delivering CSP that may be used in conjunction with the techniques described herein are generally disclosed in U.S. Publication No. 2022 / 0023640 (Zhou et al.) and U.S. Patent No. 11 / 207,529 (Zhou et al.), which are incorporated herein by reference in their entireties.

[0085] Electrodes 20, 22, 32, 34, and 35 (and any other electrodes shown or described herein) may be, but are not limited to, titanium, platinum, iridium, or alloys thereof, and may include low-polarization coatings such as titanium nitride, iridium oxide, ruthenium oxide, platinum black, etc. Electrodes 20 and 32 are shown as screw-in electrodes, which may be used as fixation members for securing the distal ends of respective leads 16 and 18 at desired pacing and sensing sites. In other examples, either lead 16 or 18 may include a fixation member that includes one or more tines, hooks, barbs, screws, or other fixation members that anchor the distal end of lead 16 or 18 at the implantation site. In some examples, electrodes 20 and 32 may be other types of tissue-piercing electrodes, such as fishhook or straight electrodes having tissue-piercing distal tips. Electrodes 22 and 34 are each shown as ring electrodes surrounding the respective lead body of lead 16 or 18 at a location near the respective tip electrode 20 or 32. In other examples, electrodes for sensing and pacing in a medical device system configured to deliver CSP may include button electrodes, spherical electrodes, segmented electrodes, or other types of electrodes.

[0086] The IMD 14 includes a housing 15 that encapsulates an electronic circuit configured to perform heart signal sensing and therapy delivery functions attributed to the IMD 14. Examples of circuits that may be included in the IMD 14 are described below in conjunction with Figure 6 The IMD 14 includes a connector assembly 12, sometimes referred to as a "connector block" or "header", having connector holes for receiving each of the respective leads 16 and 18 coupled to the IMD 14 ( Figure 2 not shown in ). Each of the leads 16 and 18 includes an insulated electrical conductor (not shown) that extends through one or more lumens within the elongated electrically insulating lead body of the respective leads 16 and 18. Each electrical conductor extends from the respective electrodes 20, 22, 32, 34, and 35 to the proximal lead connector of the corresponding lead 16 or 18 to provide an electrical connection to the electrical contacts within the connector assembly 12. The electrical connection of the electrodes 20, 22, 32, 34, and 35 to the internal electronic circuit of the IMD 14 is provided by electrical feedthroughs within the connector assembly 12 that pass through the hermetically sealed housing 15 of the IMD 14.

[0087] In this manner, the insulated electrical conductors extending through the leads 16 and 18 transmit electrical signals from the therapy delivery circuit within the housing 15 to the electrodes 20, 22, 32, 34, and / or 35 to deliver electrical stimulation pulses. The insulated electrical conductors may transmit cardiac electrical signals from the heart 8 to the sensing circuit within the housing 15 via the electrodes 20, 22, 32, 34, and / or 35 for obtaining atrial and ventricular EGM signals. As described above, the IMD 14 may communicate with the external device 50 and / or one or more computing devices 70 via wireless telemetry. For example, the external device 50 may receive EGM signals, delivered pacing pulse marker signals, and / or other CSP capture data transmitted by the IMD 14 for detecting changes in CSP capture by the processing circuitry of the external device 50, network / cloud 75, and / or computing device 70 for display to a clinician or other user.

[0088] Figure 3Conceptual diagram of IMD 14 coupled to lead 18, which is advanced to an alternative location within heart 8 to deliver CSP and sense cardiac electrical signals. In this example, the distal portion of lead 18 is advanced within the RA via a right atrial approach for sensing ventricular electrical signals and delivering CSP pulses to or near the His bundle. The pacing tip electrode 32 of lead 18 can be advanced into cardiac tissue within the His bundle region, such as between the His bundle and the coronary sinus and adjacent to the tricuspid valve. In some examples, the target entry site of electrode 32 can correspond to or be within the Koch triangle for achieving CSP at the His bundle pacing site. The pacing electrode 32 can be paired with a return anode ring electrode 34 for delivering CSP pulses and for sensing native cardiac electrical signals, which can be processed to obtain ventricular EGM signals.

[0089] In some examples, CSP can be delivered in combination with myocardial pacing of the left ventricle (LV), which can be delivered via a left ventricular lead 47 to further improve electrical and mechanical synchrony of the RV and LV, such as during cardiac resynchronization therapy (CRT). The left ventricular lead 47 can be advanced into the RA, through the coronary sinus ostium and into a cardiac vein of the LV for positioning electrodes 48a, 48b, 48c, and 48d (collectively referred to as "LV electrodes 48") along the left ventricular myocardium for sensing ventricular electrical signals and pacing the LV myocardium. The left ventricular lead 47 is shown as a quadripolar lead carrying four electrodes 48a through 48d, and the four electrodes can be selected among various bipolar pacing electrodes for pacing the myocardial tissue of the LV and sensing LV signals. One of the LV electrodes 48 can be selected in combination with the IMD housing 15 for delivering unipolar LV myocardial pacing and / or for sensing ventricular EGM signals that can be transmitted to an external device 50 via a communication link 62 in some instances. The left ventricular lead 47 can have more or fewer electrodes than the four electrodes 48 shown Figure 3 in.

[0090] When lead 18 is positioned for delivering CSP, CSP can be delivered in combination with ventricular myocardial pacing (using the left ventricular lead 47) to correct ventricular conduction delays and achieve electrical and mechanical synchrony of the ventricles. Thus, in some examples, the IMD 14 can control the combination of CSP pulse delivery and LV myocardial pacing pulse delivery at a specific time interval, which can include an AV delay and / or a ventricle-to-ventricle (VV) delay. The AV delay can control the timing of the CSP 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). (For example, when the RA lead 16 is coupled to the IMD 14, as Figure 2as shown). In some examples, the VV delay can control the timing between the CSP pulses delivered via lead 18 and the LV myocardial pacing pulses delivered via LV lead 47.

[0091] It should be understood that the left ventricular lead 47 is optional. In some examples, the IMD 14 is only coupled to the lead 18 advanced into the RA or RV for positioning at least one electrode 32 at the CSP site to deliver CSP and sense ventricular EGM signals. In other examples, as Figure 2 shown, the RA lead 16 is implanted in combination with the lead 18 for delivering CSP in a dual-chamber sensing and pacing system. In other examples, the IMD 14 can be a multi-chamber device configured to receive the lead 16, the lead 18, and the lead 47 to deliver cardiac pacing pulses to the RA, the His-Purkinje conduction system, and the LV myocardium as needed. The external device 50 (or the relay device 45) can receive one or more EGM signals sensed using any available EGM sensing electrode vector from the IMD 14. One or more EGM signals can be sensed during the CM test and transmitted as cardiac electrical signal episodes for analysis by the processing circuitry of the medical device system for detecting changes in CSP capture.

[0092] Figure 4 is a conceptual diagram of a leadless pacemaker 114 according to another example, the leadless pacemaker being positioned in the RA to provide CSP. The pacemaker 114 can include a distal tip electrode 102 located on and extending from the distal end 112 of the pacemaker housing 105. The pacemaker 114 is shown implanted in the RA of the patient's heart 8 to place the distal tip electrode 102 to deliver CSP pulses in the region of the His bundle. For example, the distal tip electrode 102 can be inserted into the lower end of the interatrial septum, below the AV node, and near the tricuspid annulus to position the tip electrode 102 in, along, or near the His bundle. The distal tip electrode 102 can be a tissue piercing electrode and, in some examples, is a screw electrode that provides fixation to anchor the pacemaker 114 in the implantation position. In other examples, the pacemaker 114 can include a fixation member that includes one or more tines, hooks, barbs, screws, or other fixation members that anchor the distal end of the pacemaker 114 at the implantation site. A portion of the distal tip electrode 102 can be electrically insulated such that only the farthest distal end of the tip electrode 102 (farthest from the distal end 112 of the housing) is exposed to provide targeted pacing at the CSP site.

[0093] One or more additional housing-based electrodes 104 and 106 may be carried on the surface of the housing 105 of the pacemaker 114 near the distal tip electrode 102. Electrodes 104 and 106 are shown as annular electrodes surrounding the longitudinal sidewall 107 of the pacemaker housing 105, and these annular electrodes may be generally cylindrical in shape. The longitudinal sidewall 107 extends from the distal end 112 of the housing 105 to the proximal end 110. One of the electrodes 104 or 106 may be used as a return anode electrode in combination with the cathode tip electrode 102 for pacing and sensing. For example, the distal tip electrode 102 may be used as the cathode electrode and either of the housing-based electrodes 104 and 106 may be used as the return anode to effect pacing of the conduction system. In other examples, the return anode electrode for sensing and pacing may be located on the proximal end 110 of the housing.

[0094] Cardiac electrical signals may be sensed by the pacemaker 114 using a sensing electrode pair selected from electrodes 102, 104, and 106. For example, the distal tip electrode 102 and the distal housing-based electrode 104 or the proximal housing-based electrode 106 may be used to sense cardiac electrical signals. Electrodes 104 and 106 may be used to sense a second cardiac electrical signal. In some examples, an atrial P wave may be sensed from the signals received via electrodes 104 and 106, and / or atrial pacing pulses may be delivered via electrodes 104 and 106. Atrial synchronous CSP pulses may be delivered via electrodes 102 and 104 with an AV delay after the sensed atrial P wave and / or the delivered atrial pacing pulses. The EGM signals sensed by the pacemaker 114 and / or the CSP capture data derived therefrom may be transmitted via the communication link 62 to an external device 50 (or transmitted via the Figure 1 network / cloud 75 shown to a computing device 70).

[0095] Figure 5 is Figure 4 a conceptual diagram of a leadless pacemaker 114 shown implanted in an alternative location for CSP. In some examples, the pacemaker 114 may be implanted within the RV along the ventricular septum 19 for providing CSP. The techniques disclosed herein may be used in combination with a leadless pacemaker (such as pacemaker 114) having a pacing electrode 102 coupled to and extending directly from the pacemaker housing 105 without the need for an intervening medical lead coupled to the pacemaker 114 for carrying the pacing and sensing electrodes.

[0096] In this example, the pacemaker 114 can be positioned within the RV to advance the pacing tip electrode 102 extending from the distal end 112 of the pacemaker housing 105 into the ventricular septum 19 for delivering CSP, for example, in the region of the lower portion of the His bundle or along one or both of the RBB and LBB (depending on the relative positioning of the distal tip electrode 102). The distal tip electrode 102 is shown as a "screw-in" helical electrode but can be configured as other types of tissue-piercing electrodes capable of advancing within septal tissue. The proximal portion of the distal tip electrode 102 can be electrically insulated, for example, having a coating such that only the distal portion of the tip electrode 102 furthest from the distal end 112 of the pacemaker housing is exposed to provide targeted pacing at tissue sites including the His bundle, LBB, and RBB.

[0097] In other examples, the distal tip electrode 102 can be formed with a straight axis having a distal active electrode portion or other types of electrodes that can be tissue-piercing electrodes that can be advanced through the ventricular septum 19 to deliver CSP in the left portion of the septum 19 in the region of, for example, the LBB. In some examples, the pacemaker 114 can include a fixation member that includes one or more tines, hooks, barbs, spirals, or other fixation members that can anchor the distal end 112 of the pacemaker 114 at the implantation site and that can not function as electrodes. Examples of leadless intracardiac pacemakers that can be configured to deliver cardiac pacing pulses to the conduction system and that can be used in conjunction with the techniques described herein are generally disclosed in U.S. Patent No. 11,207,529 (Zhou) and U.S. Publication No. 2019 / 0083800 (Yang et al.), which are incorporated herein by reference in their entireties.

[0098] The pacemaker 114 can include a distal housing-based annular electrode 104 along or near the distal end 112 of the pacemaker housing 105. In an example, the distal housing-based annular electrode 104 can be selected as the return anode electrode for use with the distal tip electrode 102 for bipolar pacing of the LBB and / or RBB near the distal tip electrode 102. Bipolar bilateral BB pacing of both the RBB and LBB simultaneously can be achieved by cathodal capture of the LBB at the distal tip electrode 102 and anodal capture of the RBB by the distal annular electrode 104. The polarities of the distal tip electrode 102 and the distal annular electrode 104 can be reversed to achieve cathodal capture of the RBB and anodal capture of the LBB in some examples. The distal annular electrode 104 is shown as an annular electrode surrounding the distal portion of the housing 105 but alternatively can be a distal housing-based electrode in the form of a button electrode, hemispherical electrode, segmented electrode, etc. and can be along the surface of the distal end 112 of the housing 105 and / or along the longitudinal sidewall 107.

[0099] In the example shown, a housing-based proximal annular electrode 106 that may surround all or a portion of the longitudinal sidewall 107 of the housing 105 may be provided as a return anode electrode. In other examples, a return anode electrode for sensing and pacing may be located on the proximal end 110 of the housing and may be a button electrode, an annular electrode, or other type of electrode. CSP in the region of the LBB may be achieved using the tip electrode 102 as the cathode electrode and the proximal annular electrode 106 as the return anode. CSP in the region of the RBB and / or myocardial tissue of the ventricular septum 19 may be achieved using the distal annular electrode 104 as the cathode electrode and the proximal annular electrode 106 as the return anode. In this manner, bilateral or biventricular pacing of the conduction system may be achieved using two different bipolar pacing electrode vectors carried by the housing 105.

[0100] The cardiac electrical signals generated by the heart 8 may be sensed by the pacemaker 114 using the electrode 102, the electrode 104, and / or the electrode 106. The cardiac electrical signals received via the electrodes 102 and 104, the electrodes 104 and 106, and / or the electrodes 102 and 106 may be sensed by the pacemaker 114 and processed by the processing circuitry of the IMD 14, and / or wirelessly transmitted as EGM signals to an external device 50 via a communication link 62 or to a computing device 70 (such as Figure 1 shown) via a network / cloud 75. These EGM signals may then be displayed and / or further processed and analyzed, for example, by a processor 52 of the external device 50, the processing circuitry 72 of the computing device 70, or cloud-based computing on the network / cloud 75, in order to provide the user with a visual representation of the sensed EGM signals and / or CSP capture data.

[0101] Figures 1 to 5 The examples presented various lead and / or electrode configurations that may be implemented for delivering CSP pacing in a medical device system configured to perform the techniques disclosed herein for analyzing cardiac electrical signals and generating CSP capture data. The various lead and electrode configurations described and shown in the figures are intended to be illustrative in nature. It should be understood that Figures 1 to 5The leads and electrodes illustrated may be implanted in different combinations and / or other locations than those shown in the example, and some leads and / or electrodes may be omitted, or additional leads and / or electrodes may be provided in a medical device system configured to deliver CSPs and monitor CSP capture. In some examples, a leadless IMD (e.g., pacemaker 114) may be implanted in a patient's body in combination with another implanted IMD (e.g., an IMD connected to an RA lead for pacing and sensing in the right atrium and / or an ICD coupled to a transvenous or non-transvenous epicardial lead for providing rapid arrhythmia detection and therapy delivery) for CSP. A variety of lead-based and leadless IMD and electrode configurations are contemplated for sensing cardiac electrical signals and delivering CSP pulses, and these IMD and electrode configurations may be used in conjunction with the techniques disclosed herein for analyzing cardiac electrical signals and presenting CSP capture data to a user, e.g., in a GUI displayed on a user display / interface 78 of an external device 50 and / or a computing device 70.

[0102] Figure 6 is a conceptual diagram of a circuit of an IMD configured to sense cardiac electrical signals and perform CSP according to some examples. Figure 6 The figure of is described with reference to IMD 14, which is coupled to electrodes 20 and 22 carried by an RA lead 16 and electrodes 32, 34, and 35 carried by a lead 18, e.g., as an illustrative example, as Figure 2 shown. However, it should be understood that due to Figure 6 the functionality of the various circuits and components for sensing cardiac signals and delivering CSPs shown in may be implemented in combination with other lead and electrode configurations, including Figure 4 and Figure 5 the leadless pacemaker 114 of or other medical devices configured to deliver CSP pulses and sense cardiac electrical signals.

[0103] The housing 15 is shown as an electrode in Figure 6 for cardiac electrical signal sensing and, in some examples, for delivering unipolar pacing pulses. When the IMD 14 is implemented as an ICD, the housing 15 may be used as an active can electrode for delivering CV / DF shock pulses. The electronic circuitry encapsulated within the housing 15 includes software, firmware, and hardware that cooperate to monitor cardiac electrical signals, determine when pacing pulses are needed, and deliver pacing electrical pulses to the patient's heart as needed according to programmed pacing modes and pacing pulse control parameters. The electronic circuitry may include a control circuit 80, a memory 82, a therapy delivery circuit 84, a cardiac electrical signal sensing circuit (also referred to herein as a "sensing circuit") 86, a telemetry circuit 88, and a power source 98.

[0104] Power source 98 provides power to the circuitry of IMD 14, which circuitry optionally includes components of circuits 80, 82, 84, 86, and 88. The power source 98 may include one or more energy storage devices, such as one or more rechargeable or non-rechargeable batteries. The connections between the power source 98 and the components of circuits 80, 82, 84, 86, and 88 will be understood from the overall block diagram of Figure 6 but are not shown for clarity. For example, the power source 98 may be coupled to one or more charging circuits included in the therapy delivery circuit 84 to provide the power required to charge a holding capacitor included in the therapy delivery circuit 84, which holding capacitor discharges at an appropriate time under the control of the control circuit 80 to deliver an electrical stimulation pulse. The power source 98 is also optionally coupled to components of the sensing circuit 86 for sensing cardiac electrical signals, such as a sensing amplifier, an analog-to-digital converter, a switching circuit, and the like. The power source 98 may optionally provide power to various components and circuits of the telemetry circuit 88 and the memory 82, which may be under the control of the control circuit 80.

[0105] Figure 6 The circuits shown represent the functionality included in IMD 14 and may include any discrete and / or integrated electronic circuit components implementing analog and / or digital circuits capable of performing the functions attributed herein to IMD 14 (or pacemaker 114). The various components may include application specific integrated circuits (ASICs), electronic circuits, processors (shared, dedicated, or groups) executing one or more software or firmware programs, combinational logic circuits, state machines, and memories, or other suitable components or combinations of components providing the described functionality. Given the disclosure herein, it is within the ability of those skilled in the art to provide software, hardware, and / or firmware to implement the described functionality in the context of any modern medical device system.

[0106] The control circuit 80, for example, communicates with the therapy delivery circuit 84 and the sensing circuit 86 via a data bus to cooperatively sense cardiac electrical signals and control the delivery of cardiac electrical stimulation therapy in response to sensed cardiac event signals (e.g., a P wave associated with atrial depolarization and an R wave associated with ventricular depolarization, or the absence thereof). The available electrodes may be selectively coupled (e.g., via a switching circuit) to the therapy delivery circuit 84 for delivering electrical stimulation pulses and / or to the sensing circuit 86 for sensing cardiac electrical signals generated by the heart. The sensed cardiac electrical signals may include intrinsic signals (such as intrinsic R waves and intrinsic R waves) generated by the heart in the absence of a pacing pulse that captures the heart, as well as evoked response signals following the delivery of a pacing pulse having sufficient energy to cause capture of cardiac tissue.

[0107] The sensing circuit 86 may include one or more sensing channels for receiving raw cardiac electrical signals from one or more sensing electrode vectors. For example, right atrial lead electrodes 20 and 22 coupled to an atrial sensing (A-sensing) channel 87 may be used to sense atrial signals. Ventricular signals may be sensed using electrodes 32, 34, and / or 35 carried by lead 18 via a ventricular sensing (V-sensing) channel 89. In some examples, the V-sensing channel 89 may include multiple ventricular sensing channels for receiving raw signals from multiple sensing electrode vectors, which may include at least one electrode within or proximal to the ventricular chamber. For example, the V-sensing channel 89 may include a near-field sensing channel for receiving raw near-field signals using electrodes 32 and 34 of lead 18 in a bipolar sensing electrode pair. The V-sensing channel 89 may include a far-field or unipolar sensing channel for receiving raw far-field signals. For example, a second electrode vector having electrodes spaced further apart than the electrodes of the near-field sensing electrode vector may be used to receive the raw far-field signal. For example, pacing electrode 32 or ring electrode 34 of lead 18 paired with the IMD housing 15 may be used to sense the far-field signal. In some examples, the V-sensing channel 89 may receive raw far-field signals sensed using pacing electrode 32 or ring electrode 34 paired with coil electrode 35. In other examples, coil electrode 35 paired with the IMD housing 15 may be used to sense the far-field signal.

[0108] The sensing circuit 86 may include switching circuitry for selectively coupling sensing electrode pairs among the available electrodes to respective sensing channels in the A-sensing channel 87 or the V-sensing channel 89. The switching circuitry may include a switch array, a switch matrix, a multiplexer, or any other type of switching device suitable for selectively coupling components of the sensing circuit 86 to the selected electrodes.

[0109] Each of the sensing channels 87 and 89 of the sensing circuit 86 may include an input filter, a preamplifier, an analog-to-digital converter (ADC), and a bandpass filter for receiving raw cardiac electrical signals from the respective sensing electrode pairs, for generating a multi-bit digital cardiac electrical signal, which may be referred to as an "intracardiac EGM" signal when raw signals are sensed using at least one electrode within the cardiac chamber. The multi-bit EGM signal may be passed from the sensing circuit 86 to the control circuit 80 for processing and analysis, and / or for transmission to an external device 50, a network / cloud 75, and / or a computing device 70 (e.g., Figure 1 as shown) for processing and analysis and / or display.

[0110] Each sensing channel 87 and 89 may include a cardiac event detection circuit, which may include one or more sensing amplifiers, filters, rectifiers, threshold detectors, comparators, analog-to-digital converters (ADCs), timers, or other analog or digital components for detecting cardiac electrical event signals. For example, an atrial event detector may be included in the A sensing channel 87 for sensing an intrinsic P wave associated with intrinsic atrial depolarization using one or both of the electrodes 20 and 22 carried by the right atrial lead 16. A ventricular event detector may be included in the V sensing channel 89 for sensing an intrinsic R wave associated with intrinsic ventricular depolarization using the electrodes 32 and 34 carried by the lead 18.

[0111] Cardiac event sensing thresholds (such as P wave sensing threshold and R wave sensing threshold) may be automatically adjusted by the sensing circuit 86 under the control of the control circuit 80, for example, based on a determined time period and sensing threshold determined by the control circuit 80, stored in the memory 82, and / or controlled by the hardware, firmware, and / or software of the control circuit 80 and / or the sensing circuit 86. For example, the R wave sensing threshold may be controlled to start at an initial threshold voltage after the ventricular post-ventricular blanking period and then decrease according to one or more decay rates and / or one or more step-downs until a minimum sensing threshold is reached. The minimum R wave sensing threshold may be set to the programmed sensitivity of the R wave detection circuit. The sensitivity, programmed as a voltage level typically in millivolts, is the lowest voltage level above which the cardiac event detection circuit of the corresponding A sensing channel 87 or V sensing channel 89 can sense a cardiac event signal, such as a P wave or an R wave.

[0112] After detecting a cardiac electrical event signal based on a sensing threshold crossing, the sensing circuit 86 may generate a sensing event signal that is transmitted to the control circuit 80. For example, an atrial event detector may generate an atrial sensing event signal in response to a P wave sensing threshold crossing. A ventricular event detector may generate a ventricular sensing event signal in response to an R wave sensing threshold crossing. The sensed event signal may be used by the control circuit 80 to initiate a pacing escape interval timer that controls the basic time intervals for scheduling cardiac pacing pulses (e.g., atrial pacing pulses) and CSP pulses and, in some cases, LV myocardial pulses.

[0113] The control circuit 80 may include various timers or counters for counting down the AV delay, VV delay, atrial pacing lower rate interval, ventricular pacing lower rate interval, or other pacing escape intervals according to the pacing mode and pacing control parameters. The sensed event signal may trigger or inhibit the pacing pulse, depending on the particular programmed pacing mode. For example, the P-wave sensed event signal received from the sensing circuit 86 may cause the control circuit 80 to inhibit the scheduled atrial pacing pulse and schedule a CSP pulse at the AV delay. If the AV delay expires before the control circuit 80 receives an R-wave sensed event signal from the sensing circuit 86, the therapy delivery circuit 84 may generate and deliver a CSP pulse at the AV delay after the sensed P wave and deliver atrial synchronous ventricular pacing in this way. If an R-wave sensed event signal is received from the sensing circuit 86 before the AV delay expires, the scheduled CSP pulse may be inhibited. The AV delay controls the amount of time between atrial events (paced or sensed) and the CSP pulse to promote electrical and mechanical synchrony of the heart chambers.

[0114] In other cases, the ventricular pacing lower rate interval (LRI) may be set by the control circuit 80 to schedule a CSP pulse after the delivered CSP pulse or sensed R wave. The LRI may correspond to the programmed ventricular lower rate or may be adjusted by the control circuit 80 to a temporary LRI to deliver rate-responsive pacing when, for example, an increase in patient activity level is detected by an accelerometer signal or other patient activity sensor included in the IMD 14 ( Figure 6 not shown). When the IMD 14 is operating in a dual-chamber pacing mode (e.g., DDD mode), when a P wave is sensed during the LRI, a CSP pulse may be triggered to occur at the AV delay and the LRI may be restarted when the CSP pulse is delivered. If the LRI expires without a sensed P wave or sensed R wave, a CSP pulse may be delivered at the expiration of the LRI and the LRI may be restarted. The control circuit 80 may be configured to control the therapy delivery circuit 84 to deliver CSP pulses according to various pacing modes and pacing therapies, which may include bradycardia pacing, post-shock pacing, anti-tachycardia pacing (ATP), cardiac resynchronization therapy (CRT), rate-responsive pacing, etc.

[0115] The therapy delivery circuit 84 can include a charging circuit, one or more charge storage devices (such as one or more holding capacitors), an output capacitor, and a switching circuit that controls when the holding capacitor charges and discharges across the output capacitor to deliver a pacing pulse to a selected pacing electrode vector coupled to the therapy delivery circuit 84. The therapy delivery circuit 84 can include one or more pacing channels. In the example of the IMD 14, the therapy delivery circuit 84 can include an atrial pacing channel and a ventricular pacing channel, each channel including one or more holding capacitors, one or more switches, and an output capacitor for generating a pacing pulse delivered by the respective RA lead 16 (e.g., via electrodes 20 and 22) or lead 18 (e.g., via electrodes 32 and 34). In other examples, the atrial and ventricular pacing pulses can be generated and delivered by a shared pulse generation circuit.

[0116] Charging the holding capacitor to a programmed pacing voltage amplitude and discharging the capacitor for a programmed pacing pulse width can be performed by the therapy delivery circuit 84 in accordance with control signals received from the control circuit 80. For example, the pacing timing circuit included in the control circuit 80 can include a programmable digital counter set by the microprocessor of the control circuit 80, as an example, for controlling the basic pacing time intervals associated with various single-chamber and / or dual-chamber pacing modes, and multi-chamber pacing modes when the LV lead 47 ( Figure 3 as shown) is connected to the IMD 14 for delivering CRT and / or for delivering an ATP sequence. The microprocessor of the control circuit 80 can also set the amplitude, pulse width, polarity, or other characteristics of the cardiac pacing pulses that can be based on programmed values stored in the memory 82.

[0117] The IMD 14 can be configured to detect nonsinus tachycardia and deliver ATP. When the IMD 14 is configured as an ICD for detecting tachycardia and delivering CV / DF shocks, in addition to the low-voltage therapy circuit for generating low-voltage pacing pulses, the therapy delivery circuit 84 can also include a high-voltage therapy delivery circuit for generating high-voltage shock pulses. In response to detecting ventricular tachycardia or fibrillation, the control circuit 80 can control the therapy delivery circuit 84 to deliver a CV / DF shock. The high-voltage therapy circuit can include a high-voltage capacitor and a high-voltage charging circuit for generating and delivering CV / DF shock pulses using elongated coil electrodes (e.g., coil electrode 35) carried by one or more leads coupled to the IMD 14 and / or the housing 15.

[0118] The control parameters used by the control circuit 80 for sensing cardiac event signals (e.g., P waves and R waves) and controlling pacing therapy delivery can be programmed into the memory 82 via the telemetry circuit 88. The telemetry circuit 88 can include means for using radio frequency communication or other communication protocols as described above to communicate with an external device 50 (e.g.,Figure 1 A transceiver and an antenna for communicating as shown. Under the control of the control circuit 80, the telemetry circuit 88 can receive downlink telemetry from the external device 50 or the computing device 70 and send uplink telemetry to the external device or the computing device. In some cases, the telemetry circuit 88 can be used to transmit communication signals to another medical device implanted in a patient and receive communication signals from another medical device implanted in a patient. The telemetry circuit 88 can transmit EGM signals, pacing pulse timing markers, atrial and ventricular sensing event signal markers, and other sensing and pacing-related data for real-time reception by the external device 50 and / or reception from stored EGM signal episodes, which can be displayed by the external device 50 or the computing device 70.

[0119] Figure 7 FIG. 150 is a flow chart of a method that can be performed by an IMD included in a medical device system according to some examples. For illustration, the process of flow chart 150 and other flow charts presented herein is described in connection with the IMD 14 that performs functions attributed to an implanted device that performs a CM test. It should be understood that another IMD configured to deliver CSP and sense at least one cardiac electrical signal can perform the functions attributed to the implanted device in the techniques presented herein. Additionally, in some examples, it may be possible for one IMD to deliver CSP while a second IMD and / or an external device senses and stores cardiac electrical signals, e.g., the first IMD delivers CSP pulses according to a CM test protocol. Thus, the process of flow chart 150 can be performed collaboratively by more than one medical device, e.g., including at least one IMD configured to deliver CSP pulses and one or more second implanted and / or external devices configured to sense and store cardiac electrical signals, which can be EGM and / or ECG signals recorded as cardiac electrical signal episodes during a CM test.

[0120] At block 152, the IMD 14 receives CM control parameters. In some examples, the CM control parameters used by the IMD 14 to control the time of performing the CM test and / or how to perform the CM test can be programmed by the user to customize the CM test for the needs of an individual patient. In some examples, the programmable CM control parameters are used by the IMD 14 to select a pacing output based on the CM test.

[0121] Figure 8FIG. 180 is a conceptual diagram of a GUI that can be displayed to a user on an external device 50 or via a computing device 70 according to some examples to enable the user to program CM control parameters. FIG. 180 may represent a screenshot or window of a CM programming screen that can be displayed by a display unit 54 of the external device 50 or by a user display / interface 78 of the computing device 70. The user may select the CM programming screen to program control parameters that are used by the IMD 14 to perform CM testing and, in some cases, for automatic programming adjustments after the CM testing.

[0122] In this example, the IMD 14 is a dual-chamber device such that the CM programming screen includes an atrial channel 181 for CM control parameters and a ventricular channel 182 for CM control parameters. Each of the atrial channel 181 and the ventricular channel 182 may include a programmable capture management mode 184, a currently effective pacing pulse amplitude 185 (or a programming value to be determined), an amplitude safety margin 186, a minimum capture amplitude 187, a pulse width 189, and a maximum test amplitude 190 used in the CM testing. The ventricular channel 182 may include a programmable CSP safety margin 188 that can be applied by the control circuit 80 to select the currently effective pacing pulse amplitude 185 for the ventricular channel 182 (CSP for the ventricle), as described below. It may be assumed that ventricular pacing is delivered as CSP according to the pacing pulse amplitude 185 and pulse width 189 for the ventricular channel 182 programmed by the user or automatically programmed by the IMD 14. It should be understood that when CSP is combined with LV myocardial pacing, for example, when the LV lead 47 is coupled to the IMD 14 as shown Figure 3 a third LV channel may be included in the CM programming screen represented by FIG. 180.

[0123] In some examples, the CM mode 184 can be programmed individually for the atrial channel 181 and the ventricular channel 182 as "off", "monitor", or "adaptive". When programmed as "off", no CM testing is performed and the IMD 14 does not acquire CSP capture data. When programmed as "monitor", the IMD 14 may perform CM testing according to the programmed control parameters to acquire cardiac electrical signals sensed during the CM testing and / or data derived therefrom, but may not make any automatic adjustments to the pacing output based on the results of the CM testing. When programmed as "monitor", the IMD 14 may record the EGM signal when adjusting the pacing pulse output to store the CM test EGM signal onset, which can be transmitted by the IMD 14 for reception by the external device 50 or transmitted to the network / cloud 75 for analysis and / or transmitted to the computing device 70 (see Figure 1 ).

[0124] When programmed to be “adaptive”, the IMD 14 can perform a CM test according to programmed control parameters, store the EGM signals sensed during the CM test and adjust one or more control parameters based on the analysis of the EGM signals, such as increasing or decreasing the pacing pulse output (e.g., pacing pulse amplitude 185 and / or pulse width 189). When the capture management mode is programmed to be “adaptive”, the pacing pulse output can be automatically adapted by the IMD 14 based on one or more capture thresholds determined from the EGM episodes sensed during the CM test. For example, the control circuitry 80 of the IMD 14 can determine the capture thresholds, such as selective and / or non-selective conduction system capture thresholds, and adjust the pacing pulse amplitude to at least an amplitude safety margin 186 (which can be programmable) greater than the determined capture threshold. In the example shown, the safety margin is multiplicative as it can be programmed to be 1 times, 1.5 times, 2.0 times, 2.5 times or other multiples of the determined capture threshold. In other examples, the amplitude safety margin 186 can be additive as it can be programmed to be a fixed offset, such as 0.5 volts, 1.0 volts, 1.5 volts, 2.0 volts or 2.5 volts (V) greater than the determined capture threshold plus the determined capture threshold.

[0125] The currently effective pacing pulse amplitude 185 can be displayed. In some examples, the user can reprogram the pacing pulse amplitude 185 by selecting the atrial channel (181) or the ventricular channel (182) and entering a new pacing pulse amplitude. The amplitude safety margin 186 is a programmable safety margin that is added to or multiplied by the capture threshold determined during the CM test when the capture management mode is programmed to be “adaptive” as described above. The minimum adaptation amplitude 187 can be programmed by the user and can be the minimum pacing pulse amplitude in volts to which the IMD control circuitry 80 can automatically adjust the pacing pulse amplitude when the capture management mode is programmed to be “adaptive”.

[0126] The CSP safety margin 188 can be optional and can be a programmable safety margin that can be applied by the control circuit 80 to the capture threshold determined during CSP that captures at least a portion of the His-Purkinje conduction system. In some examples, the CSP safety margin 188 is an additional safety margin that, when the capture management mode 184 for the ventricular channel 182 is programmed to "adaptive," is added to the result of multiplying (or adding) the capture threshold by the amplitude safety margin 186 to set the pacing pulse amplitude of the CSP pulse. For example, if the conduction system capture threshold is determined to be 1.5V and the safety margin is 2X, the control circuit 80 can determine the CSP pulse amplitude to be 3V (the capture threshold multiplied by the safety margin) plus the programmed CSP safety margin 188, for example, plus 1V in this illustrative example or a total of 4V. For example, the CSP safety margin 188 can be programmed to be between 0.25V and 3V. In other examples, the CSP safety margin 188 can be programmed as a multiplicative value rather than an additive one. For example, the CSP safety margin 188 can be programmed to be 1.0 times to 2.0 times the result of multiplying (or adding) the conduction system capture threshold by the amplitude safety margin 186.

[0127] When "Allow automatic reprogramming?" 191 is enabled, the CSP safety margin 188 can be automatically adjusted by the control circuit 80. When automatic adjustment of the CSP safety margin 188 is enabled, the CSP safety margin can increase or decrease when the conduction system capture threshold increases or decreases such that the CSP pulse amplitude is maintained at a desired safety margin relative to the capture threshold of the desired capture threshold type (e.g., non-selective or selective capture of the target CSP site).

[0128] In some examples, for each of the atrial channel 181 and the ventricular channel 182, the maximum test amplitude 190 can be programmable. The maximum test amplitude 190 is the maximum pulse amplitude of the corresponding atrial pacing pulse or CSP pulse delivered by the therapy delivery circuit 84 during atrial or CSP CM testing. The maximum test amplitude 190 can be programmed between 3V and 10V, and in some examples can be programmed between 5V and 8V, and in some cases can be set to the maximum available pacing pulse amplitude.

[0129] The pulse width 189 can be programmable for each of the atrial channel 181 and the ventricular channel 182. The pulse width 189 can be maintained at the programmed value during all CM testing and during pacing of the respective atrial or ventricular chambers. However, it should be appreciated that in other examples, the pacing pulse amplitude 185 can be held fixed during CM testing and during pacing of the respective atrial or ventricular chambers, where the pacing pulse width 189 is adjusted during CM testing and is automatically or manually reprogrammed based on the capture threshold determined from the CM testing.

[0130] The CM programming screen shown in FIG. 180 may include a capture management test schedule 192 that enables a user to program a CM test start time and a repeat interval. For example, a user may program the CM test to start executing at 2:00 a.m. and repeat every 24 hours. As an example, the start time may be programmable to any time of day and the repeat interval may be programmable to one hour, four hours, eight hours, 12 hours, 24 hours, 48 hours, 72 hours, or one week.

[0131] Note that the various values of the programmable parameters listed for the atrial channel 181 and the various values of the programmable parameters listed for the ventricular channel 182 are illustrative in nature and are not considered restrictive. The value of each programmable parameter may be selected automatically by the user and / or by the control circuit 80 from the corresponding range of values.

[0132] Returning to Figure 7 , at block 154, the control circuit 80 may determine that it is time to perform a CM test based on the programmed start time and repeat interval, one or both of which may be user programmable as described above. In some examples, the control circuit 80 may determine that it is time to perform a CM test based on other criteria in addition to the programmed CM test schedule. For example, a CM test may be performed in response to a user command received via the telemetry circuit 88.

[0133] Additionally or alternatively, the control circuit 80 may determine that it is time to perform a CM test in response to detecting a CM test trigger condition determined from sensed cardiac electrical signals, such as a change in QRS waveform morphology, a change in the activation time between a delivered CSP pulse and QRS waveform characteristics, or another change in QRS waveform characteristics, such as slope, amplitude, area, width, etc., which may indicate a change in the type of capture after a CSP pulse. A change in QRS waveform morphology and / or one or more specific QRS waveform characteristics may be detected by the control circuit 80 by determining QRS waveform characteristics that are compared to values or template values stored in the memory 82 corresponding to a desired CSP capture type, such as selective or non-selective conduction system capture. In other examples, the control circuit 80 may detect a change in the QRS waveform based on comparing the QRS waveform sensed after the most recent CSP pulse to the QRS waveform sensed after an earlier CSP pulse.

[0134] If the control circuit 80 determines that it is not yet time to perform a CM test, the control circuit 80 may wait at block 154 until it is determined that the time to perform the CM test has arrived. In some cases, the IMD 14 may receive new CM control parameters at block 152 while waiting to perform the next CM test.

[0135] When the control circuit 80 determines that the time to perform a CM test has arrived, the control circuit 80 controls the therapy delivery circuit 84 to deliver one or more CSP pulses at each CSP pulse output in one or more CSP pulse outputs (e.g., using one or more pacing pulse amplitudes with a fixed pulse width, or vice versa) according to the CM control parameters programmed at block 156. During the CSP CM test, the therapy delivery circuit 84 may begin the CM test by delivering N CSP pulses at the programmed maximum test amplitude ( Figure 8 190 in). The therapy delivery circuit 84 may be controlled by the control circuit 80 to deliver CM test pacing pulses at a shortened pacing interval (e.g., at a shortened AV delay or at a shortened ventricular lower rate interval) to overdrive any intrinsic ventricular electrical activity. The therapy delivery circuit 84 may be controlled by the control circuit 80 to decrease the CSP pulse amplitude after each delivery of N CSP pulses until the programmed minimum pulse amplitude is reached.

[0136] The minimum pulse amplitude used during the CM test may be the programmed minimum adapted amplitude 187 as shown in Figure 8 or another programmed minimum pulse amplitude or the lowest available pacing pulse amplitude of the therapy delivery circuit 84. In some examples, the programmable CM control parameters may include a programmable minimum test amplitude in addition to the minimum adapted amplitude. The minimum test amplitude may be lower than the minimum adapted amplitude or other optional settings by one decrement. In some examples, the user may select whether CM test pacing pulses may be delivered below the programmed minimum adapted amplitude. In some cases, the pacing pulse amplitude may be decreased until the control circuit 80 detects loss of capture from the sensed cardiac electrical signals (e.g., no evoked response after a CSP pulse), which may occur before the minimum allowable pacing pulse test amplitude is reached.

[0137] The number of CSP pulses delivered at each pacing pulse amplitude can be between one and twelve CSP pulses and can be three to five pacing pulses. In an illustrative example, during a CSP CM test, the therapy delivery circuit 84 can deliver five CSP pulses at a maximum test amplitude of 5V and reduce the pulse amplitude by 0.25V using a fixed pulse width after every five CSP pulses. As an example, the fixed pulse width can be between 0.1ms and 2ms and in some examples can be 0.03ms to 1.5ms. In other examples, the pulse amplitude can be fixed at a programmed or default value and the pulse width can be set to a maximum starting pulse width, such as 1.2ms to 2.0ms, which is reduced every N pacing pulses until a minimum pulse width, such as 0.03ms to 0.5ms, is reached.

[0138] During the CM test, the sensing circuit 86 senses one or more EGM signals, which can be passed to the control circuit 80 for storage in the memory 82. As the CSP pulse output decreases and the capture type changes and / or capture loss occurs, one or more changes in the QRS morphology are expected in the EGM signals recorded during the CSP CM test. Multichannel EGM episodes can be recorded during the CSP CM test. For example, at least one relatively near-field EGM signal and / or at least one relatively far-field EGM signal are stored in the memory 82 as CSP CM test data. The near-field EGM signal is a relatively local signal that can be recorded at or near the CSP site. The far-field signal can be a relatively more global signal that can be recorded using at least one electrode located away from the CSP site and can represent the global coordination or synchronization of ventricular electrical depolarization. Each of the near-field EGM signal and the far-field EGM signal can contain capture-related information, which can be used to determine the type of CSP capture achieved at each pacing pulse output and to detect changes in CSP capture that may require adjustment of the CSP pulse output and / or alerting a clinician or other user, as further described below. In some examples, for example, atrial EGM signals sensed using Figure 1 the electrodes 20 and 22 shown in can be stored together with one or more ventricular EGM signals. Pacing event markers (e.g., CSP pulse markers and optional atrial pacing pulse markers) and any intrinsically sensed P-wave markers and / or intrinsically sensed R-wave markers can be stored together with the EGM episode.

[0139] In some examples, an EGM episode can be a single continuous episode that includes a CM test from the start of the first CSP test pulse to the last CSP test pulse. An EGM episode (which can be a multi-channel EGM episode that includes two or more EGM signals) can be recorded at a selected sampling rate (e.g., 128 Hz to 512 Hz) over a duration of about 10 seconds, 30 seconds, 60 seconds, 120 seconds, or other duration, depending on the time to complete the CM test. The time to complete the CM test can depend on the number of CSP pulses delivered at each pacing pulse output, the number of test pacing pulse outputs used during the test, and the pacing rate. In other examples, an EGM episode can be recorded in a discontinuous manner, e.g., to reduce the memory capacity required to store the EGM episode and / or to achieve a higher sampling rate of the EGM episode stored in memory 82. The EGM episode can be stored at block 158 as one or more QRS waveforms recorded for each CM test pacing pulse output. For example, one to three QRS waveforms can be stored in memory 82 in association with each pacing pulse amplitude delivered during the CM test. Each QRS waveform can be recorded in memory 82 over a time interval, e.g., having a duration of 200 ms to 600 ms or a duration of about 250 ms to 500 ms, starting from the delivered CSP pulse or after a post-pacing blanking interval (e.g., 20 ms to 70 ms).

[0140] At block 160, telemetry circuit 88 can transmit the EGM signal episode stored in memory 82 during the CM test. The EGM signal episode is transmitted by IMD 14 for receipt by an external device 50 or a computing device 70 (which can be via relay device 45 and / or network / cloud 75), e.g., for processing and analysis. As further described below, the processing circuitry of the medical device system can analyze the EGM signal episode to detect an alert condition that can indicate a change in CSP capture, which may require adjustment or reprogramming of the CSP pulse output. In the illustrative examples given herein, the analysis of the EGM episode recorded during the CM test is described as being performed by the processing circuitry after the recorded EGM episode is transmitted from IMD 14 to, e.g., an external device 50 or network / cloud 75. The external device processor 52, the computing device processing circuitry 72, and / or the cloud-based software of network / cloud 75 can perform the processing and analysis of the EGM episode for detecting a change in CSP capture. However, it should be understood that the analysis of the EGM episode recorded by IMD 14 during the CM test can be performed in whole or in part (e.g., collaboratively) by any processing circuitry included in the processing circuitry of the medical device system, including IMD control circuit 80, external device processor 52, network / cloud 75, and / or computing device processing circuitry 72.

[0141] Figure 9 is a flow chart 200 of a method for detecting an alert condition from an EGM episode recorded during a CM test that can be performed by a processing circuit of a medical device system (e.g., Figure 1 medical device system 10). As indicated above, the processes of flow chart 200 can be performed by an external device processor 52, a computing device processing circuit 72, cloud-based software executed by a processor of a network / cloud 75, or any combination thereof.

[0142] At block 202, the processing circuit receives the transmitted cardiac signal episode obtained by an IMD (e.g., IMD 14) configured to deliver CSP during a CM test, as described above in connection with Figure 7 generally described. At block 204, the processing circuit analyzes the cardiac signal episode to detect capture changes. As described below, capture changes can be detected relative to a previous CM test. A capture change can be detected when a different number or type of morphological changes occur during a CM test as the CSP pulse output decreases (or changes), and / or when morphological changes occur at a different pacing pulse output level than during a previous CM test. For convenience, the processes of flow chart 200 and other flow charts and figures presented herein are described in connection with receiving a cardiac electrical signal episode as an EGM episode, where one or more EGM signals sensed by IMD 14 are transmitted for receipt by the processing circuit. However, it should be understood that in addition to or instead of EGM signals, a cardiac signal episode can include one or more ECG signals (e.g., when sensing cardiac electrical signals using epicardial, submuscular, or subxiphoid electrodes or external, surface, or skin electrodes).

[0143] In some examples, a change in capture during a CM test can be detected without identifying or differentiating capture types, such as differentiating selective conduction system capture, non-selective conduction system capture, and VMO capture. In other examples, the processing circuit of the medical device system can be configured to classify the capture type as one of a plurality of possible capture types, e.g., any one of selective conduction system capture, non-selective conduction system capture, bilateral bundle branch capture, partial or complete right bundle branch capture, partial or complete left bundle branch capture, partial or complete His bundle capture, VMO capture, and / or capture loss. When a classification of the capture type is available, the processing circuit can detect an alert condition when the number or type of detected captures is different compared to a previous CM test. When capture thresholds associated with each classification of the capture type are available, e.g., the lowest pacing pulse output at which a particular capture type is identified, a change in the capture threshold associated with the capture type can be detected as an alert condition at block 206 compared to a previous CM test.

[0144] In some examples, an alert condition can be detected at block 206 when a change in morphology or capture type occurs at a CM test pacing pulse output that is different from the CM test pacing pulse output corresponding to a morphological change or capture type change that occurred during a previous CM test (e.g., the difference from the CM test pacing pulse output is greater than a threshold voltage difference). In an illustrative example, when a specific change in QRS morphology or a change in capture type occurs at 3.0V in the current CM test and the same QRS morphology change or change in capture type occurred at 3.25V in the previous CM test, a 0.25V change in the CSP pulse output can be recognized as an alert condition at block 206. In other examples, a relatively large threshold change (e.g., at least 0.5V) in the pacing pulse output may be required to detect an alert condition. For example, a relatively small change in the pacing pulse output corresponding to a QRS morphology change indicating a change in capture type may be just within the safety margin of the pacing amplitude.

[0145] When one or more changes in the CM test compared to the previous CM test are detected, the processing circuit can detect an alert condition at block 206. If an alert condition is detected, the processing circuit can generate an alert condition output at block 208. The alert condition output can include a message or notification of a CSP capture change that can be displayed by an external device 50 or a computing device 70. The alert condition output can include generating a display of a GUI including all or a portion of an EGM episode, which can include markings of QRS morphologies that occur at different CSP pulse output levels compared to the previous CM test, QRS morphologies that did not occur during the previous CM test, QRS morphologies that occurred during the previous CM test but did not occur during the current CM test, QRS morphology feature changes, and the corresponding CSP pulse output settings at which the QRS morphology feature changes occurred. In some examples, when the processing circuit determines the capture type, a change (increase or decrease) in the capture threshold of a specific capture type can be reported in the alert condition output that can be generated at block 208.

[0146] In some cases, the processing circuit determines that the EGM episode received for the most recent CM test is not different from the EGM episode determined for the previous CM test. For example, the analysis at block 204 can result in the same number of QRS morphology types or the same number of classified capture types as the previous CM test. The analysis at block 204 can result in the same number of QRS morphology types or identified capture types as the previous CM test, each occurring at a pacing pulse output that is generally the same. "Same" pacing pulse output can be defined as within ±0.1V, ±0.2V, ±0.25V, ±0.3V, ±0.5V, or other specified threshold differences, or can be defined as a percentage of the pacing output, a percentage of the amplitude safety margin, a percentage of the CSP safety margin, or other specified thresholds.

[0147] When the EGM episode analysis does not meet the criteria for detecting a change in the detected EGM episode compared to the previous CM test EGM episode, the processing circuit can generate a notification of an undetected alert condition at block 210. The EGM episode or portions thereof and / or data derived therefrom can be made available for display on the external device 50 or the computing device 70 for viewing by a clinician or other caregiver. However, because an undetected alert condition is detected, a notification that the CM test result and / or the capture threshold is stable or unchanged can be generated at block 210. After generating an output based on the detection or non-detection of an alert condition, the processing circuit can return to block 202 to wait for the next EGM episode transmission.

[0148] Figure 10 is a flowchart 201 of a method for detecting and responding to changes in CSP capture that can be performed by a processing circuit of a medical device system (e.g., Figure 1 medical device system 10). Figure 10 The boxes with the same numbers in Figure 9 correspond to the boxes with the same numbers above. When the processing circuit detects an alert condition at block 206, one or more capture thresholds associated with the CSP may have changed since the previous CM test. As a result, programming changes may be required to facilitate effective CSP under the output, which may achieve the desired capture type, such as selective or non-selective capture of at least a portion of the conduction system.

[0149] At block 212, the processing circuit can receive user input indicating that a programming change is needed. The user notified by the alert condition output generated at block 208 can determine that CSP control parameters (e.g., pacing pulse amplitude and / or pulse width) may need to be increased or decreased due to the processing circuit detecting a change in the CM test EGM episode relative to the previous CM test.

[0150] In other examples, the processing circuit can be configured to determine that a programming change is needed without requiring user input. For example, the processing circuit can be configured to determine capture test data, as described below (e.g.) in connection with Figure 11is further described. The capture test data can include identifying the QRS morphology type corresponding to each pacing pulse output (e.g., pulse amplitude) delivered during the CM test. The capture test data determined by the processing circuit can additionally or alternatively include the pacing pulse output at which, during an EGM episode, one QRS morphology type changes to another QRS morphology type (e.g., determining the capture threshold for each QRS morphology type). The number of different QRS morphology types can be identified without having to determine what type of capture the QRS morphology type represents. However, the capture test data determined by the processing circuit can also include classifying the QRS morphology at each pacing pulse output according to one of a plurality of capture types. The processing circuit can determine the capture threshold for each classified capture type. The number of QRS morphology types of the EGM episode and / or the number of classified capture types can be determined as capture test data in the analysis performed by the processing circuit at block 204.

[0151] When the capture test data determined by the processing circuit changes compared to a previous CM test, the processing circuit can determine at block 212 that a programming change is needed. The change in the capture test data can be detected as a different number of QRS morphology types, a different number of capture type classifications, or different pacing pulse outputs (or a range of pacing pulse outputs) at which a QRS morphology type or classified capture type or capture loss occurs compared to the previous CM test. In response to detecting a change in the capture test data, the processing circuit can determine at block 212 that a programming change is needed.

[0152] In an example where the processing circuit is configured to determine one or more capture thresholds, the processing circuit can determine that a programming change is needed based on a threshold difference of the capture threshold compared to the capture threshold of an earlier CM test determined previously. In other examples, when a particular morphological feature or QRS morphology type is determined to be different compared to the QRS morphology type at the same pacing pulse output during the previous CM test at the currently programmed CSP pulse output (e.g., the current pacing pulse amplitude effective since the last CM test) or any test pacing pulse output during the CM test, the processing circuit can determine that a programming change is needed.

[0153] When the processing circuit determines that a programming change is needed based on received user input or analysis of an EGM episode, the medical device system can receive programming input from the user, for example, via the user display / interface 78 of the computing device 70 or via the user interface 56 and / or display unit 54 of the external device 54. At block 214, the processing circuit can control the communication circuit 76 of the computing device 70 or the telemetry unit 58 of the external device 50 to transmit a programming command via an associated communication network or wireless telemetry link. The IMD 14 can receive the programming command and adjust one or more CSP control parameters accordingly.

[0154] For example, if an indication of an increase in the capture threshold for a desired capture type is determined from an EGM episode, the pacing pulse output, such as the CSP pulse amplitude or pulse width, may be increased to facilitate effective CSP. In other cases, if an indication of a decrease in the capture threshold is determined, the pacing output may be decreased to conserve IMD power 98. In some examples, the programming command may include a change to the amplitude safety margin, CSP safety margin, maximum test amplitude, minimum adapted amplitude, and / or the CM test schedule start time and / or the repeat interval. In some examples, the programming command may include a change in the capture management mode, such as a change between an adaptive mode, a monitoring mode, or off. Example programmable parameters that may be programmed based on CM test EGM episode analysis were described above in connection with Figure 8 described. If no programming change is needed (the "no" branch of block 212) or after the programming data (e.g., commands and settings) is transmitted at block 214, the processing circuitry may return to block 202 to wait for the next EGM episode to be transmitted.

[0155] Figure 11 FIG. 250 is a flow diagram of a method for detecting an alert condition of an EGM episode by processing circuitry of a medical device system according to some examples. The process of flow diagram 200 may be incorporated, in whole or in part, in the methods of flow diagrams 200 or 201 for detecting an alert condition by identifying changes in an EGM episode received for a most recent CM test compared to an EGM episode received for a previous CM test.

[0156] At block 251, the processing circuitry may determine one or more characteristics of the QRS waveform morphology after a CM test pacing pulse delivered at a first pacing pulse output of the CM test (e.g., at a maximum CM test pacing pulse amplitude). The first QRS morphology of the EGM episode may be characterized by determining one or more characteristics, such as peak amplitude, inter-peak amplitude, QRS width, QRS area, activation time from the delivered pacing pulse to a fiducial point of the QRS waveform (e.g., maximum peak amplitude), maximum positive slope, maximum positive slope time (starting from the delivered pacing pulse), maximum negative slope, maximum negative slope time, morphology match score, or any other QRS morphology characteristic or any combination thereof. The morphology match score may be determined by wavelet transform, correlation analysis, or other techniques to determine a match score between the QRS waveform and a stored QRS template, e.g., the match score may correspond to a known capture type.

[0157] At block 252, the processing circuitry may compare the first QRS morphology of the EGM episode to the first QRS morphology of a previous CM test EGM episode. In some cases, if the starting maximum pacing pulse output has changed, the first QRS morphology of the EGM episode may be compared to a QRS morphology that is not the first QRS morphology of the previous CM test. In such cases, the first QRS morphology of the current EGM episode corresponding to the starting (e.g., maximum) CM test pacing pulse output may be compared to the QRS morphology identified for the same pacing pulse output in the previous CM test, which may or may not be the first starting pacing pulse output. The EGM episodes and / or capture test data determined therefrom recorded for at least one previous CM test for a given patient may be stored in the external device memory 53, the computing device memory 74, or on a server of the network / cloud 75. In this way, the processing circuitry of the medical device system may compare between the current EGM episode and the previous CM test EGM episode. Additionally or alternatively, QRS morphology data (such as any one of the QRS features listed above) determined from at least one previous EGM episode and the associated pacing pulse output may be stored in the memory of the medical device system.

[0158] For the same pacing pulse output, if one or more features of the first QRS morphology present in the EGM episode differ from the corresponding features of the QRS morphology present in the previous EGM episode (from a previous CM test), the processing circuitry may detect an alert condition at block 262 (the "yes" branch of block 252). For example, assume that both the current and previous CM tests start with the same maximum test amplitude. If the capture threshold has not changed, the QRS morphology is expected to be the same in both EGM episodes. If the first QRS morphology present in the current EGM episode is determined to be different from the first QRS morphology present in the previous EGM episode, a change in CSP capture may have occurred. In an example that includes different starting test pacing pulse outputs (e.g., different maximum test amplitudes), the processing circuitry may determine and compare the QRS morphology features corresponding to the earliest equal pacing pulse outputs delivered during the current CM test and the previous CM test.

[0159] If the first QRS morphology of the EGM episode is not different from the first QRS morphology of a prior CM test EGM episode (or the QRS morphology of an equivalent pacing pulse output), the processing circuit may proceed to block 254 to identify the next QRS morphology that occurs during the EGM episode and is different from the first QRS morphology. When the processing circuit detects an alarm condition (block 262) based on a different first QRS morphology (the "yes" branch of block 252), the processing circuit may determine at block 260 whether the EGM episode includes another QRS morphology (different from the first QRS morphology). If so, the processing circuit may proceed to block 254 to identify the associated next QRS morphology characteristics and the associated pacing pulse output.

[0160] When a second QRS morphology is identified during an EGM episode (e.g., after one or more decrements of the pacing pulse amplitude during a CM test), the processing circuit may determine whether the second QRS morphology and the associated pacing pulse output at which the second QRS morphology first appears during the EGM episode represent a change from a prior CM test EGM episode. In some cases, the second QRS morphology that occurs during an EGM episode when the pacing pulse output is decreased may be the same QRS morphology as the second QRS morphology in a prior CM test EGM episode. Based on a comparison of waveform morphology characteristics or using morphology matching techniques, the second QRS morphology of the current EGM episode may be determined to be the same as the second QRS morphology. However, the highest pacing pulse output at which the second QRS morphology first appears in the current EGM episode may be different from the highest pacing pulse output at which the second matching QRS morphology first appears in a prior CM test EGM episode. When the pacing output at which the second QRS morphology appears in the current EGM episode is different from the pacing output at which the second QRS morphology appears in a prior CM test EGM episode (the "yes" branch of block 256), the processing circuit may detect an alarm condition at block 262.

[0161] In other cases, the second QRS morphology in the current EGM episode may be different from the second QRS morphology that occurred in a prior CM test EGM episode. When the second QRS morphology in the current EGM episode is different from the second QRS morphology in a prior CM test EGM episode (the "yes" branch of block 258), the processing circuit may detect an alarm condition at block 262.

[0162] Accordingly, the processing circuit can detect a CSP capture change when the QRS morphology in the current EGM episode is different from the QRS morphology that occurred at the same pacing pulse output during a previous CM test EGM episode. Additionally or alternatively, a CSP capture change can be detected by the processing circuit when the same QRS morphology first appears at a different pacing pulse output in the current EGM episode compared to a previous EGM episode. A CSP capture change can be detected when the nth QRS morphology identified during a CM test (e.g., when the pacing output is decreased) is different from the nth QRS morphology identified during a previous CM test. When a CSP capture change is detected based on a comparison between the current EGM episode and a previous CM test EGM episode, the processing circuit can detect an alarm condition at block 262.

[0163] When the pacing output is decreased (or increased or otherwise changed), the process of identifying the next QRS morphology that appears in the EGM episode can continue to identify one or more CSP capture changes that may occur at one or more pacing pulse outputs in the current CM test EGM episode compared to a previous CM test EGM episode. When no further morphological changes are identified within the current EGM episode (the "no" branch of block 260) or when the last QRS waveform of the EGM episode has been evaluated, the processing circuit can determine at block 264 whether the total number of QRS morphology types presented in the current EGM episode is different from the total number of QRS morphology types presented in a previous CM test EGM episode.

[0164] In some cases, non-selective capture of the conduction system with ventricular myocardial capture can occur until the pacing pulse output is reduced below the conduction system capture threshold. Below the conduction system capture threshold, VMO capture can occur until the pacing pulse output is reduced below the VMO capture threshold, at which point capture loss may occur. In this illustrative example, there can be three different QRS morphologies corresponding to non-selective conduction system capture, VMO capture, and capture loss during a CM test EGM episode. At other times, in the same patient, selective conduction system capture, non-selective conduction system capture with ventricular myocardial capture, VMO capture, and capture loss may occur during a CM test. In such cases, there can be four different QRS morphologies corresponding to each type of capture during an EGM episode. In still other examples, the different QRS morphologies identified from an EGM episode sensed during a CM test can correspond to any of the following (not intended to be limiting): selective partial His bundle capture, selective complete His bundle capture, non-selective partial His bundle capture, non-selective complete His bundle capture, selective LBB capture, non-selective LBB capture, selective bilateral BB capture, non-selective bilateral BB capture, selective RBB capture, non-selective RBB capture, VMO capture, and capture loss.

[0165] Accordingly, the processing circuitry can determine at block 264 whether a different number of QRS morphologies (or a different number of QRS morphology changes) are present in the EGM episode compared to a previous CM test. When a different number of QRS morphologies are identified, the processing circuitry can detect an alert condition at block 266. When the number of QRS morphologies identified during the EGM episode has not changed compared to the previous CM test, the processing circuitry can proceed directly to block 268.

[0166] At block 268, the processing circuitry can generate an alert condition output based on the number and type of alert conditions detected (which in some cases can be no alert conditions detected). The generated alert condition output can be received and stored in the memory of the medical device system, and the alert condition output can be a notification to a clinician or other caregiver indicating whether an alert condition has been detected from the current EGM episode. The alert condition output can include a display (e.g., in a GUI) or report (e.g., a summary sheet, a graph, etc.) of the CSP capture changes identified as alert conditions, and these changes can include one or more changes in the identified QRS morphologies, changes in the pacing output when a given QRS morphology occurs, and / or changes in the number of identified QRS morphologies. The alert condition output can include a display of the EGM episode or a segment from the EGM episode that represents any identified CSP capture changes detected as alert conditions.

[0167] In some examples, the generated alert condition output can include recommended or automatic programming changes. For example, when the lowest pacing pulse output for a given QRS morphology increases compared to a previous CM test, an automatic or recommended increase in pacing pulse amplitude, pulse width, amplitude safety margin, or CSP safety margin can be provided as the output at block 268. When the lowest pacing pulse output for a given QRS morphology decreases, an automatic or recommended decrease in pacing pulse amplitude, pulse width, amplitude safety margin, or CSP safety margin can be provided as the output at block 268.

[0168] In other examples, if no change in CSP capture is identified as an alert condition for a threshold number of CM tests, the repetition interval for performing CM tests can be increased. If a change in CSP capture is identified as an alert condition, the repetition interval for performing CM tests can be decreased such that CM tests can be performed more frequently to enable programming changes to the CSP pulse output as needed. Adjustments to the maximum CM test pulse output and / or minimum CM test pulse output can be made or recommended by the medical device processing circuitry based on the detected alert condition.

[0169] Figure 12 FIG. 300 is a flow diagram of a method for analyzing CM test EGM episodes by a processing circuitry of a medical device system to detect changes in CSP capture according to another example. At block 302, the processing circuitry of the medical device system receives a CM test EGM episode. At block 304, the processing circuitry analyzes the EGM episode to detect morphological changes within the EGM episode that indicate a change in the type of capture that occurred during the CM test.

[0170] The processing circuitry can distinguish the type of capture based on an analysis of the QRS morphology following each CM test pacing pulse. Different types of capture that can be identified by the processing circuitry are listed as examples above. The processing circuitry can determine the QRS waveform characteristics following the CM test pacing pulse. For example, the QRS waveform characteristics can be determined from one or more EGM signals sensed during a post-pacing window following a CSP pulse delivered during the CM test. The QRS waveform characteristics can be determined for comparison with each other and / or with various thresholds, ranges, or other criteria in capture detection and classification algorithms performed by the processing circuitry. Some examples of QRS waveform characteristics that can be analyzed during CSP to classify different types of capture are generally disclosed in U.S. Application Publication No. 2020 / 0406041 (Cao et al.), U.S. Patent Application No. 17 / 735,628 (Zhou et al.), and U.S. Patent Application No. 17 / 370,303 (Cao et al.), the contents of all of which are incorporated herein by reference in their entirety.

[0171] In other examples, the processing circuitry can provide an EGM episode, or a selected portion thereof, as input to a machine learning model or other AI model for analyzing the input and providing a capture type output that can include an indication of a capture type classification and a classification confidence level (e.g., as a percentage confidence). AI techniques for CSP capture type classification can include deep learning techniques such as convolutional neural networks (CNNs), residual CNNs, feedforward neural networks (FFNNs), recurrent neural networks (RNNs), transformers, or other machine learning techniques such as decision trees, random forest models, or other machine learning methods for building a model to classify delivered CSP pulses (and corresponding post-pacing QRS waveforms) according to capture type. Each CSP pulse (or each CSP pulse output) delivered during a CM test can be classified according to capture type based on a post-pacing unknown cardiac signal input from the received EGM episode.

[0172] A CSP capture classification model implemented in the processing circuitry of a medical device system can learn from cardiac electrical signal data obtained from a patient population using machine learning. In some examples, the processing circuitry is trained to perform a capture classification algorithm by using at least one other template beat input to classify a post-pacing EGM waveform in a CM test EGM episode input received from the IMD 14, the at least one other template beat input representing a QRS waveform following a CSP pulse having a preselected pacing pulse output. The template beat input can be a patient-specific template generated from one or more QRS waveforms obtained following a CSP pulse delivered at a specified pacing pulse amplitude.

[0173] As described above, an EGM episode can include one or more cardiac electrical signals. For example, two EGM signals, including a near-field EGM signal and a far-field EGM signal, can be included in an EGM episode. The near-field signal can be a bipolar ventricular EGM signal, an EGM signal sensed with a relatively small interelectrode distance, and / or an EGM signal sensed using an electrode near the CSP site, to generally provide a signal representative of relatively local ventricular electrical activity. The far-field EGM signal can be a unipolar ventricular EGM signal, an EGM signal sensed with a relatively large interelectrode distance, and / or an EGM signal sensed using an electrode positioned away from the CSP site, to generally provide a signal more representative of global ventricular electrical activity than the near-field EGM signal. One or both of the near-field EGM signal and / or the far-field EGM signal can be provided as an input to an AI model that is a multi-channel input. In other examples, three, four, or more cardiac electrical signals can be used as inputs to the AI model for capture type classification. Other input signals that can be used to train the AI model and can subsequently be received for generating a capture classification of an unknown post-pacing signal in a CM test EGM episode can include the CM test pacing pulse amplitude (and / or width), the derivative of the cardiac electrical signal waveform, one or more QRS waveform templates, and / or one or more QRS waveform morphological features determined from the EGM episode, such as activation time, signal width, signal area, peak amplitude, peak-to-peak amplitude, peak polarity, etc. Examples of AI techniques are generally disclosed in U.S. Patent Application No. 63 / 337,769 (Berlin et al.), which can be implemented in combination with the techniques disclosed herein to provide a capture type classification of CM test pulses delivered during a recorded EGM episode, the entire content of which patent application is incorporated herein by reference.

[0174] In addition to analyzing the EGM episode to understand morphological changes that occur within the EGM episode when the CM test pacing pulse output changes, the processing circuit can analyze the EGM episode to identify capture-related changes compared to a previous CM test EGM episode. The previous CM test EGM episode received from the IMD 14 and / or capture test data derived therefrom can be stored in the memory of the medical device system for comparison with subsequent CM test EGM episodes. For example, capture-related changes relative to a previous CM test EGM episode can include the number of QRS morphologies present in the current EGM episode compared to the previous CM test EGM episode, the difference in CM test pacing pulse output at which QRS morphology changes occur compared to the previous CM test EGM episode, and / or the difference in QRS morphology at the same pacing pulse output compared to the previous CM test EGM episode. Capture-related changes compared to a previous CM test EGM episode can be identified as an alert condition at block 304 (e.g., according to any of the examples described herein).

[0175] At block 306, the processing circuitry may generate CM test data for display to a clinician or other user. The CM test data may include an EGM episode or a portion thereof, CM test pacing pulse output, CSP pulse markers, atrial pacing pulse markers, intrinsic sensing event markers, changes in QRS morphological characteristics that occur within the EGM episode when the CM test pacing pulse output changes, and / or capture type classification (if available). The CM test data may additionally or alternatively include capture-related changes identified between the current EGM episode and a previous CM test EGM episode as described above. The CM test data may include any alert conditions detected by the processing circuitry based on a detected difference between the current EGM episode and a previous CM test EGM episode according to any of the examples above. The CM test data may be displayed on the external device display unit 54 and / or the computing device user display / interface 78, such as in a GUI.

[0176] At block 308, the processing circuitry may receive user input to identify one or more EGM episode waveforms (and associated CM test pacing pulses) as capture types or significant morphological changes. In some examples, QRS waveforms of EGM episodes at different CM test pacing pulse outputs may be displayed to a clinician or other user such that the user can label one or more QRS waveforms according to capture type or according to QRS morphological type (e.g., morphology 1, morphology 2, etc.). In some examples, QRS waveforms of EGM episodes may be classified by the processing circuitry according to capture type. A clinician or other user may re-label capture types that may have been misclassified by the processing circuitry based on ground truth. In some cases, the user input received at block 308 may be a ground truth input to confirm the capture type classification or QRS waveform morphology labeled in the GUI based on a determination made by the processing circuitry. In various examples, the user input received at block 308 may include labels or annotations for one or more paced beats in the EGM episode, which may be corrections or confirmations of labels or annotations generated by the processing circuitry, or may be labels or annotations applied to unpaced beats of the EGM episode. In some cases, the user may label or annotate one or more paced beats of the EGM episode at each CM test pacing pulse output. In other examples, the user may label each morphological type (which may occur at multiple CM test pacing pulse outputs) as a numbered or otherwise classified morphological type or as a specially classified capture type.

[0177] If no user input is received at block 310, or if no new or corrected label is received such that any user input received at block 308 would confirm an existing label or annotation generated by the processing circuitry (the "No" branch of block 310), the processing circuitry may proceed to block 314. When a user input label including a new label and / or a correction to a label or annotation generated by the processing circuitry is received at block 310, the processing circuitry may return to block 304 to re-analyze capture-related changes of the EGM episode. In this way, the expert truth of the annotated QRS morphology that occurs during the CM test can be used as feedback in the algorithm executed by the medical device system processing circuitry for detecting alert conditions for CM test EGM episodes. The processing circuitry may use the user input to personalize the algorithm for a particular patient and / or improve the algorithm for a patient population, e.g., in a cloud-based computational algorithm or an AI model. Thus, in some examples, at block 312, the processing circuitry may adjust the algorithm or criteria (such as morphology feature thresholds, ranges, or other criteria) based on the user input received at block 310 to improve the detection of QRS morphology changes within the current CM test EGM episode and / or improve the detection of capture-related changes compared to previous and / or future CM test EGM episodes. When an AI model is used to classify or annotate QRS morphology, the user input may be used to retrain the model to improve the confidence level of the label or capture type classification output by the model.

[0178] The EGM episode analysis may be repeated one or more times at block 304 based on the user input received at block 308. In other examples, after receiving the user input at block 308, the processing circuitry may update or adjust the EGM analysis algorithm at block 312 without repeating the analysis of the current EGM episode. Instead, after any adjustment is made to the algorithm or criteria for detecting QRS morphology changes within the EGM episode and / or for detecting capture-related changes between the current EGM episode and previous and / or future CM test EGM episodes at block 312, the process of flowchart 300 may proceed to block 314. In some examples, the adjustment to the EGM analysis algorithm or criteria made at block 312 may be omitted. The processing circuitry may rely on the EGM analysis algorithm and criteria to detect QRS morphology changes and / or perform capture type classification without adjustment at block 312, but the processing circuitry may use the user input received at block 308 to detect alert conditions at block 314.

[0179] At block 314, the processing circuitry may detect one or more alert conditions indicative of capture-related changes relative to a previous CM test EGM episode. The processing circuitry may detect the alert conditions based on the first EGM episode analysis performed at block 304 and any user input received at block 308 (the EGM episode analysis need not be adjusted or repeated after receiving the user input). In other examples, the processing circuitry may detect the alert conditions based on the EGM episode analysis repeated at block 304 after receiving user input at block 308 (and optionally making any adjustments to the EGM episode analysis at block 312). At block 314, any of the above example alert conditions may be detected based on a comparative analysis between the current EGM episode and the previous CM test EGM episode (which may also include labels for the QRS morphology type and / or capture classification input by the user) after receiving any user entry of expert truth for the QRS morphology type and / or capture classification. In some cases, when the EGM episode is not significantly different from the previous CM test EGM episode, the processing circuitry may not detect an alert condition. In such cases, it should be understood that the medical device system may generate and display an appropriate output indicating no capture-related changes detected, no alert condition detected, and / or no programming change required. When no alert condition is detected at block 314, the process may return to block 302 to wait for receipt of the next EGM episode transmitted by the IMD 14.

[0180] When an alert condition is detected at block 314, an alert condition output may be generated at block 316. For example, a display of any detected capture-related changes relative to the previous CM test EGM episode may be generated, where the detected differences in the current EGM episode compared to the previous EGM episode are prominently presented or annotated in the GUI. Examples of alert condition outputs that may be generated at block 316 are described above. In some examples, recommended programming changes may be displayed at block 316, such as increased or adapted pacing pulse output, amplitude safety margin, CSP safety margin, minimum adjustment amplitude, maximum test amplitude, minimum test amplitude, and / or CM test schedule changes.

[0181] In other examples, the processing circuitry may receive user input indicative of a programming change at block 318. A clinician or other user may select a programming change based on the displayed CM test data and / or the generated alert condition output, such as programming a change to any of the example programmable parameters listed above and described in connection with Figure 8 If no programming change is required, the process may return to block 302 to wait for receipt of the next transmitted CM test EGM episode.

[0182] When the processing circuitry determines at block 318 that a programming change is needed based on a detected alert condition or based on a programming command received from a user, corresponding programming data is transmitted at block 320 to the IMD 14. The computing device 70 can be used by a clinician or other user to remotely receive and transmit programming commands via the network / cloud 75 and optionally via a relay device 45 as shown in Figure 1 In other examples, the external device telemetry unit 58 can transmit programming data to the IMD 14. The processing circuitry of the medical device system can be configured to automatically select programming changes to one or more CM control parameters. Corresponding programming commands can be transmitted without approval from a clinician or other caregiver. In other cases, the programming commands can be transmitted after a clinician or other user receives and authorizes the programming commands. In other cases, a clinician or other user enters the programming commands and initiates transmission of the programming commands to the IMD 14. After transmitting any programming data required when a programming change is needed (or recommended), the processing circuitry can return to block 302 to wait for receipt of the next CM test EGM episode transmitted by the IMD 14.

[0183] Figure 13 FIG. 400 is a diagram of a GUI that can be generated by a medical device processing circuitry for displaying captured test data to a user according to some examples. In the example shown, CSP pulse markers are shown, which are labeled as ventricular pacing (VP) markers 402 and 404. The CSP pulse markers 402 and 404 can be labeled with the corresponding pacing pulse amplitudes shown (3.5 V or 3.25 V in this example). In other examples, each of the CSP pulse markers 402 and 404 can be labeled with pulse width, AV delay, or ventricular lower rate interval, pacing mode (e.g., DDD, VVI, etc.), and / or other CSP control parameters.

[0184] The GUI of FIG. 400 is also shown as including a portion of an EGM episode 410 received for the most recent CM test. The user can observe the QRS waveforms following each of the CSP pulse markers 402 and 404 in the EGM episode 410. Although only a portion of the EGM episode 410 is shown as being Figure 13 displayed, it should be understood that the entire EGM episode can be displayed in the GUI and the user can scroll forward and backward and / or zoom in and out on segments of the EGM episode. In some examples, segments of the EGM episode 410 can be selected by the processing circuitry for display in the GUI to show representative QRS waveforms at each CM test pacing pulse output and / or representative QRS waveforms when QRS morphology changes from one pacing beat to the next.

[0185] One or more QRS waveforms of an EGM episode 410 can be annotated, for example, according to a morphology type 412 (shown as numbered Morphology 1, 2, etc.) and / or according to a capture type classification 414. A processing circuit can analyze the EGM episode to identify the number of different QRS waveform morphologies that occur during a CM test. In the example shown, two different morphology types are identified prior to detecting LOC, shown as annotated Morphology 1 and Morphology 2. In some examples, the intrinsic QRS morphology when capture is lost (or if there is complete AV block, then the QRS waveform is lost) can count as a morphology type. In other examples, the EGM signal waveform after a CSP pulse that results in LOC may not be counted as a morphology type by the processing circuit because it is not associated with capture of cardiac tissue and the QRS waveform may not be present. Morphology type labels can be generated by the processing circuit to annotate the QRS waveforms of the EGM episode as, for example, type 1, 2, 3, etc., or type A, B, C, etc. or other annotation systems to distinguish the different QRS waveform morphologies that the processing circuit identifies as being present during the CM test.

[0186] When the processing circuit is configured to classify the identified QRS waveform morphologies according to capture type, a capture type classification label 414 can be generated for annotating one or more QRS waveforms in the display portion of the EGM episode 410. In the example shown, the first two CSP pulses marked by VP marker 402 are shown as being delivered at a 3.5 V pacing pulse amplitude. The next two CSP pulses marked by VP marker 404 are shown as being delivered at a 3.25 V pacing pulse amplitude. When the CSP pulse amplitude is decreased from 3.5 V to 3.25 V, a morphology change from morphology type 1 to morphology type 2 occurs. In this illustrative example, the processing circuit can identify morphology type 1 as non-selective (NS) capture of at least a portion of the His-Purkinje system that occurs with capture of the ventricular myocardium. When the CSP pulse amplitude is decreased to 3.25 V, the processing circuit identifies morphology type 2 as being VMO capture. In this case, conduction system capture is lost at 3.25 V, indicating an NS conduction system capture threshold of 3.5 V. The processing circuit can generate an NS capture type label 414 for annotating the first two QRS waveforms associated with VP marker 402, and generate a VMO capture type label 418 for annotating the next two QRS waveforms associated with VP marker 404. As the pacing pulse output is further decreased, an LOC label can be generated when morphology type 2 changes (or disappears).

[0187] In some examples, a user interacting with the GUI represented in FIG. 400 can select any one of the morphology type labels 412 and 416 and / or capture type labels 414 and 418 displayed in the GUI and enter a corrected label. In other examples, the processing circuitry can identify and label different morphology types without labeling the capture type. The user can label the capture type and can enter a corrected label for the QRS morphology type during the process of labeling the capture type. As described above, the processing circuitry can use this user input to re-evaluate the EGM episode to identify changes in the EGM episode relative to a previous CM test EGM episode. In some examples, the processing circuitry can use the user input labels of one or more QRS morphologies classified according to the morphology type and / or capture type to adjust the algorithms or criteria for identifying QRS morphologies and / or classifying capture types. For example, new thresholds, ranges, or other criteria for identifying different QRS morphology types or capture types can be established based on the relabeled morphology waveform or one or more specific features of the morphology waveform.

[0188] The GUI can include a Capture Management Report (CM Report) 430 that can present summary data derived by the processing circuitry from the EGM episode. The CM Report 430 can include data related to the current CM test and optionally one or more previous CM tests. In the example shown, data determined from three CM tests are shown, each test having a corresponding date 432. It should be appreciated that if more than one CM test is performed daily according to the programmed CM test repetition interval, the date and time of each CM test can be displayed. In various examples, the processing circuitry can generate CM test data that can include the number of morphology types 434 identified in the corresponding CM test EGM episode, the capture thresholds 436 and 438 for each morphology type (e.g., expressed as pulse amplitude in volts or pulse width in milliseconds as shown) and / or the CSP pulse output at the time of occurrence of LOC 440. In this way, the number of morphology types and / or the changes in the capture thresholds associated with each morphology type can be displayed for comparison between CM tests. In some examples, a representative QRS waveform for each morphology type can be displayed for each CM test. In this way, the changes in QRS morphologies relative to each other can be observed.

[0189] As described in the various examples given above, the processing circuitry can be configured to identify one or more changes in the EGM episode of the current CM test compared to the EGM episode of a previous CM test as an alert condition. In Figure 13In an illustrative example, the capture threshold for Morphology Type 1 is increased from 3V (in two previous CM tests) to 3.5V in the current CM test. This change in the capture threshold associated with the morphology type can be detected by the processing circuitry as an alert condition. The processing circuitry can generate an alert condition output that can include data that visibly shows the CM test change identified as the alert condition. As Figure 13 shown, the increased capture threshold associated with Morphology Type 1 can be highlighted and / or labeled as a change alert 432 to notify a clinician or other user of the detected alert condition. The GUI can have a reprogram button 432 that the user can select to open a programming window for reprogramming one or more of the CM control parameters as described above, such as Figure 8 shown in the programming GUI of FIG. 180. One or more alert conditions can be identified and visibly shown in the capture management report 430 to notify the clinician that reprogramming may be required.

[0190] It should be understood that, according to the examples, certain actions or events of any of the methods described herein can be performed in a different order in parallel, can be added, combined, or completely omitted (e.g., not all of the described actions or events are necessary for practicing the described methods). Additionally, in some examples, the actions or events can be performed simultaneously, e.g., by multithreaded processing, interrupt processing, or multiple processors, rather than sequentially. Further, for clarity purposes, although some aspects of the present disclosure are described as being performed by a single processor, circuitry, or unit, it should be understood that the techniques of the present disclosure can be performed by a combination of processors, units, or circuitry associated with, for example, a medical device system.

[0191] In one or more examples, the described functionality can be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functionality can be stored as one or more instructions or code on a computer-readable medium and executed by one or more hardware-based processing units. The computer-readable medium can include a computer-readable storage medium, which corresponds to a tangible medium, such as a data storage medium (e.g., RAM, ROM, EEPROM, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer).

[0192] The instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general microprocessors, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other equivalent integrated or discrete logic circuitry. Thus, the term “processor” as used herein may refer to any of the foregoing structures or any other structure suitable for implementing the techniques described herein. Additionally, the techniques may be implemented entirely in one or more circuits or logic elements.

[0193] Accordingly, a medical device system has been presented in the foregoing description with reference to specific examples. It should be understood that the various aspects disclosed herein may be combined in different combinations than those presented in the specific combinations shown in the figures. It should be understood that various modifications may be made to the reference examples without departing from the scope of the present disclosure and the following claims.

Claims

1. A medical device system, the medical device system comprising: a processing circuit configured to: receive cardiac electrical signal episodes sensed during a conduction system capture management test; determine capture test data from the cardiac electrical signal episodes; compare the capture test data with previous capture test data determined from a previous conduction system capture management test; and generate an output based on the comparison of the capture test data with the previous capture test data; and a memory configured to store the output.

2. The medical device system according to claim 1, wherein the processing circuit is further configured to detect an alert condition corresponding to a change in the capture test data compared to the previous capture test data; and wherein the medical device system further comprises a display unit in communication with the processing circuit for receiving the generated output and displaying data in a user interface based on the generated output and the alert condition.

3. The medical device system according to any one of claims 1 to 2, wherein the processing circuit is configured to determine the capture test data by identifying the number of different QRS waveform morphologies in the cardiac electrical signal episodes.

4. The medical device system according to claim 3, wherein the processing circuit is further configured to detect an alert condition by determining that the number of different QRS waveform morphologies in the cardiac electrical signal episodes is different from a previous number of QRS waveform morphologies identified in previous cardiac electrical signal episodes sensed during the previous conduction system capture management test.

5. The medical device system according to any one of claims 3 to 4, wherein the processing circuit is further configured to determine the capture test data by determining a capture threshold for one or more of the different QRS morphologies identified in the cardiac electrical signal episodes.

6. The medical device system according to claim 5, wherein the processing circuit is further configured to detect an alert condition by determining that a capture threshold determined for at least one of the different QRS morphologies identified in the cardiac electrical signal episodes is different from a previously determined capture threshold determined for a corresponding QRS morphology identified in the previous cardiac electrical signal episodes sensed during a previous capture management test.

7. The medical device system according to any one of claims 1 to 6, wherein the processing circuit is further configured to determine the capture test data by classifying at least one QRS waveform in the cardiac electrical signal episodes according to a capture type.

8. The medical device system according to any one of claims 1 to 7, wherein the processing circuit is further configured to determine the capture test data by classifying a plurality of QRS waveforms in the cardiac electrical signal episodes according to a plurality of capture types.

9. The medical device system according to claim 8, wherein the processing circuit is further configured to determine a capture threshold for one or more of the classified capture types among the plurality of capture types of the cardiac electrical signal episodes.

10. The medical device system according to claim 9, wherein the processing circuit is further configured to detect the alert condition by determining a change in the capture threshold determined for at least one of the classified capture types compared to a previous capture threshold determined for the at least one of the classified capture types in the previous conduction system capture management test.

11. The medical device according to any one of claims 8 to 10, wherein the processing circuit is further configured to determine an alert condition by determining that a classified capture type among the plurality of capture types occurs under a pacing pulse output in the plurality of pacing pulse outputs of the conduction system capture management test and that the classified capture type among the plurality of capture types does not occur under the pacing pulse output in the plurality of pacing pulse outputs of the previous conduction system capture management test.

12. The medical device system according to any one of claims 2 to 11, wherein the processing circuit is further configured to receive a user input via the user interface, the user input annotating at least one QRS waveform of the cardiac electrical signal episode according to at least one of a morphology type or a capture type.

13. The medical device system according to claim 12, wherein the processing circuit is further configured to adjust capture test data determined from the cardiac electrical signal episode in response to receiving the user input.

14. The medical device system according to any one of claims 1 to 13, wherein the processing circuit is further configured to determine the capture test data by classifying each post-pacing waveform among the plurality of post-pacing waveforms of the cardiac electrical signal episode according to a capture type selected as one or more of: selective conduction system capture, non-selective conduction system capture, ventricular myocardial capture only without capture of the conduction system, left bundle branch capture, partial left bundle branch capture, right bundle branch capture, partial bundle branch capture, complete His bundle capture, partial His bundle capture, or capture loss.

15. The medical device system according to any one of claims 1 to 14, the medical device system further comprising a communication circuit configured to receive the cardiac electrical signal episode transmitted from an implantable medical device, the cardiac electrical signal episode including at least one electrocardiogram signal.

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