Emergency alerting for detection of cardiac pacing lead dislodgement

Abstract

A system includes sensing circuitry configured to sense a physiological signal of a patient via one or more electrodes disposed on an implantable medical lead coupled to a medical device of the system; and processing circuitry configured to: determine that one or more features of the physiological signal are indicative of potential right ventricular (RV) lead dislodgement; determine a patient risk level of the patient based on one or more of: an underlying heart rate of the patient; or user input indicative of the patient risk level; and based on the determination that one or more features of the physiological signal are indicative of potential RV lead dislodgement and the patient risk level meeting a criterion, send an emergency alert to a user.

Description

Atly Ref. No.: A0012234W001EMERGENCY ALERTING FOR DETECTION OF CARDIAC PACING LEAD DISLODGEMENT

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 707,873, filed October 16, 2024, the entire content of which is incorporated herein by reference.FIELD

[0002] This disclosure generally relates to medical devices and, more particularly, to cardiac therapy delivery by implantable medical devices.BACKGROUND

[0003] Implantable medical devices (HMDs), including pacemakers and implantable cardioverter-defibrillators (ICDs), record physiological signals, e.g., cardiac electrogram (EGM) signals, for sensing cardiac events. In some cases, such devices are configured to detect cardiac events based on the physiological signals, such as episodes of cardiac arrhythmia. Example arrhythmia types include cardiac arrest (e.g., asystole), ventricular tachycardia (VT), and ventricular fibrillation (VF). The devices may store ECG and other physiological signal data collected during a time period including an episode as episode data. Such cardiac events are associated with significant rates of death, particularly if not treated quickly.

[0004] For example, VF and other malignant tachyarrhythmias are the most commonly identified arrhythmia in sudden cardiac arrest (SCA) patients. If this arrhythmia continues for more than a few seconds, it may result in cardiogenic shock and cessation of effective blood circulation. Reliable detection and treatment of potentially life-threatening ventricular tachycardia (VT) and ventricular fibrillation (VF) requires reliable sensing of cardiac signals. Dislodgement or dislocation of right ventricular (RV) pacing leads can result in an inability to sense the RV electrical activity appropriately. Moreover, dislodgement of the RV lead can result in loss of pacing capture, which can result in a wide range of symptoms, such as fatigue, lightheadedness, and syncope. Additionally, in some patients, loss of pacing capture can lead to sudden cardiac death (SCD). The survivalAtly Ref. No.: A0012234W001 rate from SC A decreases between 7 and 10 percent for every minute that the patient waits for defibrillation. Consequently, sudden cardiac death (SCD) may result in a matter of minutes.SUMMARY

[0005] Aspects of this disclosure are directed to a system for generating emergency alerts in response to detecting potential pacing lead, e.g., right ventricular (RV) lead, dislodgement. The system may include an implantable medical device (IMD) configured to sense one or more physiological signals of a patient. To detect RV lead dislodgement, the system may identify atrial activity on a ventricular cardiac electrogram (VEGM) of the patient, identify a change in impedance of the patient, identify a change in pacing capture threshold (PCT) of the patient, e.g., loss of pacing capture in the patient, identify a change in P-wave amplitude of the patient, and / or identify a change in R-wave amplitude of the patient. Upon detecting potential RV lead dislodgement, the system may determine whether to generate an emergency alert based on a risk level of the patient. In some examples, the risk level is based on an underlying heart rate of the patient, and the system may compare the underlying heart rate to one or more thresholds, and based on the comparison(s), determine whether to send the emergency alert. In some examples, if the system determines not to send an emergency alert, the system may determine to send a non-emergency alert.

[0006] In some examples, based on the underlying heart rate, the system may determine whether to send a prompt to the patient to confirm the emergency alert, e.g., send a prompt to the patient to confirm the patient is feeling symptomatic, which may be indicative of the potential RV lead dislodgement, before sending the emergency alert. In some examples, based on the underlying heart rate, the system may determine to bypass sending the prompt to the patient. In some examples, the IMD senses the underlying heart rate of the patient. In some examples, the system includes a wearable device configured to sense the underlying heart rate of the patient. The IMD, the wearable device, and / or another external device of the system, e.g., a patient smartphone, may be configured to determine whether to send the emergency alert and may send the emergency alert.

[0007] The emergency alert may be an alert to emergency medical services (EMS). In some examples, the system additionally or alternatively sends the emergency alert to theAtly Ref. No.: A0012234W001 patient, a caregiver, a clinician, and / or nearby hospital staff. Sending the emergency alert may include dialing an emergency dispatch service, such as 911.

[0008] The techniques of this disclosure may provide one or more technical and clinical advantages. As an example, by sending an emergency alert in response to detecting potential RV lead dislodgement, the techniques of this disclosure may enable rapid alerting and therefore treatment of RV lead dislodgement, which may improve patient outcomes. For example, patients with low underlying heart rates, e.g., patients with severe bradycardia, and patients with a history of or at risk of experiencing ventricular tachyarrhythmias may be at risk of experiencing sudden cardiac arrest (SCA), which can lead to sudden cardiac death (SCD) within a matter of minutes. By rapidly alerting EMS, the techniques of this disclosure may facilitate treatment of RV lead dislodgement via emergent life-saving intervention (e.g., transcutaneous pacing or external defibrillation) and prevent SCD in patients.

[0009] Additionally, by determining whether to send the emergency alert based on a patient risk level, which may be based on one or more of user input, e.g., clinician input, indicative of the patient risk level or an underlying heart rate of the patient, the techniques of this disclosure may facilitate identifying patients at particularly high risk of SCA or other symptoms and may prioritize alerting EMS to treat such patients. Some patients with relatively higher rate underlying heart rates may be at lower risk of SCD and may not need EMS immediately. By determining whether to send the emergency alert, e.g., as opposed to a non-emergency alert, the techniques of this disclosure may prevent the unnecessary use of EMS resources on non-emergency matters.

[0010] In one example, a system comprises: sensing circuitry configured to sense a physiological signal of a patient via one or more electrodes disposed on an implantable medical lead coupled to a medical device of the system; and processing circuitry configured to: determine that one or more features of the physiological signal are indicative of potential right ventricular (RV) lead dislodgement; determine a patient risk level of the patient based on one or more of: an underlying heart rate of the patient; or user input indicative of the patient risk level; and based on the determination that one or more features of the physiological signal are indicative of potential RV lead dislodgement and the patient risk level meeting a criterion, send an emergency alert to a user.Atty Ref. No.: A0012234W001

[0011] In another example, a method comprises: determining, by processing circuitry of a system comprising an implantable medical lead coupled to a medical device, that one or more features of a physiological signal are indicative of potential right ventricular (RV) lead dislodgement, wherein the medical device comprises sensing circuitry configured to sense the physiological signal of the patient via one or more electrodes disposed on the implantable medical lead; determining, by the processing circuitry, a patient risk level of the patient based on one or more of: an underlying heart rate of the patient; or user input indicative of the patient risk level; and sending, by the processing circuitry and based on the determination that one or more features of the physiological signal are indicative of potential RV lead dislodgement and the patient risk level meeting a criterion, an emergency alert to a user.

[0012] In another example, a non-transitory computer-readable medium stores instructions that when executed cause processing circuitry of a system to: determine that one or more features of a physiological signal are indicative of potential right ventricular (RV) lead dislodgement, wherein sensing circuitry of the system is configured to sense the physiological signal via one or more electrodes disposed on an implantable medical lead coupled to a medical device of the system; determine a patient risk level of the patient based on one or more of: an underlying heart rate of the patient; or user input indicative of the patient risk level; and based on the determination that one or more features of the physiological signal are indicative of potential RV lead dislodgement and the patient risk level meeting a criterion, send an emergency alert to a user.

[0013] This summary is intended to provide an overview of the subject matter described in this disclosure. It is not intended to provide an exclusive or exhaustive explanation of the apparatus and methods described in detail within the accompanying drawings and description below. Further details of one or more examples are set forth in the accompanying drawings and the description below.BRIEF DESCRIPTION OF DRAWINGS

[0014] FIG. l is a conceptual diagram illustrating an example implantable medical device (IMD) system, in accordance with one or more techniques of this disclosure.Atty Ref. No.: A0012234W001

[0015] FIG. 2 is a block diagram illustrating an example system configured to detect lead dislodgments, and to respond to such detections, in accordance with one or more techniques of this disclosure.

[0016] FIG. 3 is a block diagram illustrating an example configuration of an IMD, in accordance with one or more techniques of this disclosure.

[0017] FIG. 4 is a block diagram illustrating an example configuration of an external device, in accordance with one or more techniques of this disclosure.

[0018] FIG. 5 is a block diagram illustrating an example configuration of the computing system of FIG. 2, in accordance with one or more techniques of this disclosure.

[0019] FIG. 6 is a graphical representation of a potential RV lead dislodgement, in accordance with one or more techniques of this disclosure.

[0020] FIG. 7 is a flowchart illustrating an example operation for determining to generate an emergency alert in response to determining potential right ventricular (RV) lead dislodgement based on a physiological signal and an underlying patient heart rate, in accordance with one or more techniques of this disclosure.

[0021] FIG. 8 is a flowchart illustrating an example operation for determining to generate an emergency alert in response to determining potential RV lead dislodgement based on a physiological signal and a patient risk level, in accordance with one or more techniques of this disclosure.

[0022] FIG. 9 is a flowchart illustrating an example operation for determining to generate an emergency alert in response to determining potential RV lead dislodgement based on a comparison between timings of atrial sensed events and ventricular sensed events and one or more additional features being indicative of the potential RV lead dislodgement, in accordance with one or more techniques of this disclosure.

[0023] FIG. 10 is a flowchart illustrating an example operation for determining whether to generate an emergency alert in response to determining potential RV lead dislodgement based on an underlying heart rate of a patient, in according with one or more techniques of this disclosure.

[0024] FIG. 11 is a flowchart illustrating an example operation for determining whether a ventricular cardiac electrogram (VEGM) signal is indicative of ventricular lead migration, in accordance with one or more techniques of this disclosure.Atty Ref. No.: A0012234W001

[0025] FIG. 12 is a conceptual diagram illustrating an example user interface of an external device, in accordance with one or more techniques of this disclosure.

[0026] Throughout the disclosure, like reference characters refer to like elements throughout the figures and description.DETAILED DESCRIPTION

[0027] FIG. 1 conceptual diagram illustrating an example implantable medical device (IMD) system, in accordance with one or more techniques of this disclosure. As illustrated in FIG. 1, a medical device system 8 for sensing cardiac events and detecting tachyarrhythmia episodes, e.g., ventricular tachycardia (VT), e.g., polymorphic VT (PVT) and ventricular fibrillation (VF), may include an implantable medical device (IMD) 10, a ventricular lead 20 and an atrial lead 21. In one example, IMD 10 may be an implantable cardioverter-defibrillator (ICD) capable of delivering electrical therapy such as pacing, cardioversion and defibrillation therapy to the heart 23 of a patient 14. In other examples, IMD 10 may be a pacemaker capable of delivering pacing therapy, including antitachycardia pacing (ATP) to the patient, but need not include the capability of delivering cardioversion or defibrillation therapies. In some examples, IMD 10 may be configured to deliver conduction system pacing.

[0028] Ventricular lead 20 and atrial lead 21 are electrically coupled to IMD 10 and extend into the patient's heart 23. Ventricular lead 20 includes electrodes 22 and 24 shown positioned on the lead in the patient's right ventricle (RV) for sensing ventricular EGM (VEGM) signals and pacing in the RV. Atrial lead 21 includes tip electrode 26 and ring electrode 28 positioned on the lead in the patient's right atrium (RA) for sensing atrial EGM signals and pacing in the RA.

[0029] In the example of FIG. 1, ventricular lead 20 additionally carries a high voltage coil electrode 42, and atrial lead 21 carries a high voltage coil electrode 44, used to deliver cardioversion and defibrillation shock pulses. In other examples, ventricular lead 20 may carry both of high voltage coil electrodes 42 and 44 or may carry another high voltage coil electrode in addition to those illustrated in the example of FIG. 1. Both ventricular lead 20 and atrial lead 21 may be used to acquire cardiac electrogram (EGM) signals from patient 14 and to deliver therapy in response to the acquired data. In this disclosure a cardiac EGM refers to the signal from the lead electrodes of an implanted device. In otherAtly Ref. No.: A0012234W001 examples, an electrocardiogram (ECG) refers to signals from electrodes on the skin surface or subcutaneous electrodes.

[0030] Medical device system 8 is shown as a dual chamber ICD including atrial lead 21 and ventricular lead 20, but in some examples, system 8 may be a dual or multichamber system including a coronary sinus lead extending into the right atrium, through the coronary sinus and into a cardiac vein to position electrodes along the left ventricle (LV) for sensing LV EGM signals and delivering pacing pulses to the LV.

[0031] In some examples, ventricular lead 20 is anchored along the right ventricular apex or the intraventricular septum by a fixation member (not shown), such as tines positioned at the distal end of lead 20 in the vicinity of electrode 22 or a helical screw, which may also serve as electrode 22. Use of a fixation member generally anchors the position of ventricular lead 20 in the RV. However, on rare occasions, ventricular lead 20 may become dislodged from the ventricular myocardium and shift or migrate within the ventricle or toward or within the right atrium, which may cause sensing issues. In other examples, on rare occasions, cracking or other mechanical issues with the lead conductor material or lead insulation may also cause sensing issues. In some examples, patient movement or posture may stretch or bend lead 20 or lead 21, and in examples of a lead with a mechanical issue, the movement, posture, or change in posture may intermittently cause sensing issues such as sensing circuitry of IMD 10 to detect noise. In some examples, if ventricular lead 20 becomes dislodged, ventricular lead 20 may no longer provide necessary pacing to patient 14, and patient 14 may thereby be at risk of experiencing sudden cardiac arrest (SCA), which can lead to sudden cardiac death (SCD) in a matter of minutes.

[0032] IMD circuitry configured for performing the methods described herein and an associated battery or batteries are housed within a sealed housing 16. Housing 16 may be conductive and also serve as an electrode for use as an indifferent electrode during pacing or sensing or as an active electrode during defibrillation. As such, housing 16 is also referred to herein as “housing electrode” 16 or “can electrode” 16. In other examples, an indifferent electrode may be separate from housing 16 and placed elsewhere on IMD 10, such as in the header, but perform a function similar to housing electrode 16.

[0033] EGM signal data, cardiac rhythm episode data, and lead dislodgement data acquired by IMD 10 can be transmitted to an external device 12. External device 12 mayAtly Ref. No.: A0012234W001 be a computing device, e.g., used in a home, ambulatory, clinic, or hospital setting, to communicate with IMD 10 via wireless telemetry. External device 12 may be coupled to a remote patient monitoring system, such as CareLink®, available from Medtronic Inc., of Minneapolis MN. External device 12 may be, as examples, a user device, e.g., a patient smart phone, a programmer, or an external monitor.

[0034] External device 12 may be used to program commands or operating parameters into IMD 10 for controlling IMD function, e.g., when configured as a programmer for IMD 10. External device 12 may be used to interrogate IMD 10 to retrieve data, including device operational data as well as physiological data accumulated in IMD memory. The interrogation may be automatic, e.g., according to a schedule, or in response to a remote or local user command. Programmers, external monitors, and user devices are examples of external devices 12 that may be used to interrogate IMD 10. Examples of communication techniques used by IMD 10 and external device 12 include radiofrequency (RF) telemetry, which may be an RF link established via Bluetooth, Bluetooth Low Energy (BLE), WiFi, or medical implant communication service (MICS).

[0035] In some examples, the term "near-field" may refer to an EGM recorded by two or more electrodes located in proximity to the source signal for the EGM. For example, a near-field EGM in the ventricle may be recorded from two electrodes, e.g., closely-spaced electrodes near the tip of the lead, positioned on or within the ventricle. At least one of the electrodes may be a small sensing electrode at the tip of the lead. Because these electrodes for a near-field EGM may be closely spaced, their electrical "field of view" may be short- range and dominated by the electrical signals originating in myocardium adjacent to the electrodes, such as the lead tip. The near-field EGM may have advantages for sensing local myocardial electrical activity, and HMDs, such as an ICD or pacemaker, may monitor the near-field EGM continuously to sense cardiac rhythm. As one example, a near-field EGM may be obtained by sensing between tip electrode 22 and coil electrode 44, or between tip electrode 22 and ring electrode 24 of ventricular lead 20.

[0036] A far-field EGM may include an EGM recorded by one or more electrodes located at a distance from the source of the EGM. In some examples, a ventricular far-field EGM may record ventricular activation using at least one electrode that is not in a ventricle. In some examples, the ventricular far-field EGM may refer to an EGM recorded between two or more large, widely-spaced electrodes. In some examples, electrodes mayAtty Ref. No.: A0012234W001 be separated by a distance of 10 centimeters (cm) or more. Some examples of widely spaced electrodes may include electrodes used to deliver defibrillation shocks, such as coil electrodes 42 and 44, housing electrode 16, and (in in the example dual -coil defibrillation leads), a proximal defibrillation coil and distal defibrillation coil (not shown in FIG. 1). As one specific example, a far-field EGM may be obtained by sensing between coil electrode 42 and housing electrode 16. In some examples, a far-field EGM may be referred to as the "shock" EGM recorded between two or among three widely-spaced, large shock electrodes.

[0037] One or more components of system 8 may identify potential lead dislodgement of ventricular lead 20 based on a VEGM, e.g., a ventricular far-field and / or near-field EGM, and, in some examples, an AEGM, e.g., an atrial far-field and / or near-field EGM, using the techniques described in this disclosure. For example, IMD 10 may sense a VEGM via ventricular lead 20, e.g., a near-field EGM sensed via tip electrode 22 and ring electrode 24 of ventricular lead 20, or a far-field EGM via housing 16 and high voltage coil electrode 42 (and / or in some cases high voltage coil electrode 44) on the ventricular lead. IMD 10 may sense an AEGM via atrial lead 21. One or more of IMD 10 and external device 12 may determine whether ventricular lead 20 may have dislodged based on the VEGM and the AEGM. As an example, IMD 10 and / or external device 12 may determine a correlation, e.g., a timing correlation, a duration correlation, an amplitude correlation, or another waveform correlation, between sensed events of the VEGM and the AEGM. As an example, IMD 10 and / or external device 12 may determine whether P-wave morphologies and R-wave morphologies on the VEGM and AEGM are within a threshold similarity. Based on the correlation, IMD 10 and / or external device 12 may determine whether ventricular lead 20 may have dislodged. For example, if the correlation between sensed events of the VEGM and the AEGM is indicative of simultaneous or near-simultaneous, e.g., sensed events on the VEGM occurring within 80 milliseconds of sensed or paced events on the AEGM, IMD 10 and / or external device 12 may determine ventricular lead 20 may have dislodged. External device 12 may receive the VEGM and / or data representative of the VEGM from IMD 10 via RF telemetry. In some examples, IMD 10 and / or external device 12 may determine AV intervals of patient 14 to determine whether ventricular lead 20 may have dislodged. As an example, a normal AV interval may be 120 milliseconds. If the AV interval becomes shorter than the normal AV interval, e.g., if theAtly Ref. No.: A0012234W001AV interval drops to 80 milliseconds or less, periodically or for a threshold period of time, IMD 10 and / or external device 12 may determine potential dislodgement of ventricular lead 20.

[0038] IMD 10 or external device 12 may identify one or more characteristics of the VEGM(s) or another physiological signal of the patient, e.g., an impedance signal, that are associated with potential lead dislodgement of ventricular lead 20. For example, in addition to or alternatively to determining the correlation between the VEGM and the AEGM is indicative of potential RV lead dislodgement, IMD 10 or external device 12 may determine potential lead dislodgement of ventricular lead 20 based on one or more of a change in an impedance signal, a change in pacing capture threshold (PCT) and / or signals indicative of loss of capture, a change in P-wave amplitude, or a change in R-wave amplitude. IMD 10 and / or external device 12 may provide an alert, e.g., an emergency alert, in response to detecting sensing issues with ventricular lead 20 or atrial lead 21. In some examples, IMD 10 or external device 12 may determine the correlation between the VEGM and the AEGM is indicative of potential RV lead dislodgement, and based on that determination, IMD 10 or external device 12 may determine one or more additional characteristics of the AEGM, VEGM, or another physiological signal of the patient is indicative of the potential RV lead dislodgement. In some examples, IMD 10 may alter its sensing or therapy delivery, such as withholding a ventricular defibrillation therapy, in response to detecting sensing issues.

[0039] Cardiac EGM signals, e.g., VEGM signals and AEGM signals, may be sensed in real-time and / or recorded in the memory of medical device 10 to be analyzed. In some examples, real-time sensed events may trigger medical device 10 to store cardiac EGM signals, e.g., detection of VT or VF may trigger medical device 10 to store one or more cardiac EGMs.

[0040] IMD 10 and / or external device 12 may be configured to provide an emergency alert to a user, e.g., patient 14, emergency medical services (EMS), a clinician, and / or a caregiver, to facilitate timely intervention in the event that ventricular lead 20 has potentially dislodged. In some examples, system 8 may determine a patient risk level of patient 14 to determine whether to send the emergency alert. For example, if patient 14 is high risk, system 8 may determine to send the emergency alert. If patient 14 is low risk, system 8 may determine to send a non-emergency alert. In some examples, system 8Atty Ref. No.: A0012234W001 determines the patient risk level based on clinician input. In some cases, system 8 may additionally or alternatively determine the patient risk level based on an underlying heart rate of patient 14 to determine whether to send the emergency alert to EMS.

[0041] For example, IMD 10 and / or external device 12 may detect potential dislodgement of ventricular lead 20, and based on the underlying heart rate of patient 14, IMD 10 and / or external device 12 determines whether to send an emergency alert to EMS. In some examples, IMD 10 and / or external device 12 may send the emergency alert to EMS when patient 14’ s underlying heart rate falls below a threshold, e.g.., when patient 14’s heart rate is below a threshold value, e.g., 15 beats per minute (bpm), 20 bpm, or 30 bpm. In some examples, if patient 14’s heart rate is less than a first threshold, e.g., 20 bpm or 30 bpm, but higher than a second threshold, e.g., 15 bpm, IMD 10 and / or external device 12 may prompt patient 14 to confirm the emergency alert before sending the emergency alert. If patient 14 confirms the emergency alert, e.g., by interacting with a user interface of external device 12, or if patient 14 does not respond to the emergency alert for a threshold period of time, e.g., 30 seconds, IMD 10 and / or external device 12 sends the emergency alert. If patient 14’s heart rate is less than 15 bpm, IMD 10 and / or external device 12 may bypass prompting patient 14 to confirm the emergency alert and may immediately send the emergency alert.

[0042] FIG. 2 is a block diagram illustrating an example system 2 configured to detect potential lead dislodgments, and to respond to such detections, in accordance with one or more techniques of this disclosure. As used herein, the terms “detect,” “detection,” and the like may refer to detection of lead dislodgement, e.g., RV lead dislodgement, presently (at the time the data is collected) being experienced by patient 14. The example techniques may be used with one or more patient sensing devices, e.g., IMD 10, which may be in wireless communication with one or more external devices, e.g., external devices 12A and 12B (collectively, “external devices 12”). In some examples, external devices 12A and 12B may be substantially similar to or the same as external device 12 of FIG. 1. Although not illustrated in FIG. 2, IMD 10 includes electrodes and other sensors to sense physiological signals of patient 14, e.g., a VEGM, an AEGM, an impedance signal, and / or an accelerometer signal, of patient 14, and may collect and store sensed physiological data based on the signals and detect episodes based on the data.Atty Ref. No.: A0012234W001

[0043] Although described primarily in the context of examples in which IMD 10 takes the form of an ICD or a pacemaker, the emergency alerting techniques of this disclosure may be implemented in systems including any one or more implantable or external medical devices, including monitors, wearable external defibrillators, neurostimulators, or drug pumps. Furthermore, although described primarily in the context of examples including a single implanted patient sensing device, in some examples a system includes one or more patient sensing devices, which may be implanted within patient 14 or external to (e.g., worn by) patient 14. For example, system 2 may include a patient smartwatch configured to monitor a heart rate of patient 14. As another example, system 2 may in some examples include an insertable cardiac monitor (ICM) in addition to IMD 10, which may capture different values of a common patient parameter with different resolution / accuracy based on their respective locations. In some examples, the ICM takes the form of the LINQ II™ ICM, available from Medtronic, Inc.

[0044] External devices 12 are configured for wireless communication with IMD 10. External devices 12 retrieve event data and other sensed physiological data from IMD 10 that was collected and stored by IMD 10. In some examples, external devices 12 take the form of personal computing devices of patient 14. For example, external device 12A may take the form of a smartphone of patient 14, and external device 12B may take the form of a smartwatch or other smart apparel of patient 14. In some examples, external devices 12 may be any computing device configured for wireless communication with IMD 10, such as a desktop, laptop, or tablet computer. External devices 12 may communicate with IMD 10 and each other according to the Bluetooth® or Bluetooth® Low Energy (BLE) protocols, as examples. In some examples, only one of external devices 12, e.g., external device 12A, is configured for communication with IMD 10, e.g., due to execution of software (e.g., part of a health monitoring application as described herein) enabling communication and interaction with an IMD.

[0045] In some examples, external device(s) 12, e.g., wearable external device 12B in the example illustrated by FIG. 1, may include electrodes and other sensors to sense physiological signals of patient 14, and may collect and store physiological data and detect episodes based on such signals. External device 12B may be incorporated into the apparel of patient 14, such as within clothing, shoes, eyeglasses, a watch or wristband, a hat, etc.Aty Ref. No.: A0012234W001In some examples, external device 12B is a smartwatch or other accessory or peripheral for a smartphone external device 12 A.

[0046] One or more of external devices 12 may be configured to communicate with a variety of other devices or systems via a network 260. For example, one or more of external devices 12 may be configured to communicate with one or more computing systems, e.g., computing systems 200A and 200B (collectively, “computing systems 200”) via network 260. Computing systems 200A and 200B may be respectively managed by manufacturers of IMD 10 and external devices 12 to, for example, provide cloud storage and analysis of collected data, maintenance and software services, or other networked functionality for their respective devices and users thereof. Computing system 200A may comprise, or may be implemented by, the Medtronic CareLink™ Network, in some examples. In the example illustrated by FIG. 2, computing system 200A includes processing circuitry 248, which may implement a health monitoring system (HMS) (not shown), although in other examples, either or both of computing systems 200 may implement the HMS. As will be described in greater detail below, the HMS can facilitate detection of potential RV lead dislodgement and other cardiac events of patient 14 by system 2, and the responses of system 2 to such events.

[0047] Computing device(s) 12 may transmit data, including data retrieved from IMD 10, to computing system(s) 200 via network 260. The data may include sensed data, e.g., values of physiological parameters measured by IMD 10 and, in some cases one or more of external devices 12, data regarding potential RV lead dislodgment, episodes of arrhythmia or other acute health events detected by IMD 10 and computing device(s) 12, and other physiological signals or data recorded by IMD 10 and / or computing device(s) 12. Computing system(s) 200 may also retrieve data regarding patient 14 from one or more sources of electronic health records (EHR) 240 via network. EHR 240 may include data regarding historical (e.g., baseline) physiological parameter values, previous health events and treatments, disease states, comorbidities, demographics, height, weight, and body mass index (BMI), as examples, of patients including patient 14. Computing system(s) 200 may use data from EHR 240 to configure algorithms implemented by IMD 10 and / or external devices 12 to detect RV lead dislodgement and cardiac events for patient 14. In some examples, computing system(s) 200 provides data from EHR 240 toAtty Ref. No.: A0012234W001 computing device(s) 12 and / or IMD 10 for storage therein and use as part of their algorithms for detecting cardiac events.

[0048] Network 260 may include one or more computing devices, such as one or more non-edge switches, routers, hubs, gateways, security devices such as firewalls, intrusion detection, and / or intrusion prevention devices, servers, cellular base stations and nodes, wireless access points, bridges, cable modems, application accelerators, or other network devices. Network 260 may include one or more networks administered by service providers, and may thus form part of a large-scale public network infrastructure, e.g., the Internet. Network 260 may provide computing devices and systems, such as those illustrated in FIG. 1, access to the Internet, and may provide a communication framework that allows the computing devices and systems to communicate with one another. In some examples, network 260 may include a private network that provides a communication framework that allows the computing devices and systems illustrated in FIG. 2 to communicate with each other but isolates some of the data flows from devices external to the private network for security purposes. In some examples, the communications between the computing devices and systems illustrated in FIG. 2 are encrypted.

[0049] As will be described herein, IMD 10 may be configured to detect potential RV lead dislodgement, cardiac events, and other acute events of patient 14 based on data sensed by IMD 10 and, in some cases, other data, such as data sensed by external devices 12A and / or 12B, and data from EHR 240. In response to detection of potential RV lead dislodgement, IMD 10 may wirelessly transmit a message to one or both of external devices 12A and 12B. The message may indicate that IMD 10 detected potential RV lead dislodgment of the patient. The message may indicate a time that IMD 10 detected the potential RV lead dislodgment. The message may include physiological data collected by IMD 10, e.g., data which lead to detection of the potential RV lead dislodgment, data prior to detection of the potential RV lead dislodgment, and / or real-time or more recent data collected after detection of the potential RV lead dislodgment. The physiological data may include values of one or more physiological parameters and / or digitized physiological signals, such as a digitized VEGM signal and a digitized AEGM signal.

[0050] In some examples, the detection and alerting of the potential RV lead dislodgment by IMD 10 may include multiple phases. For example, IMD 10 may complete an initial detection of the potential RV lead dislodgment and initiate wirelessAtly Ref. No.: A0012234W001 communication, e.g., Bluetooth® or Bluetooth Low Energy®, with computing device(s) 12 in response to the initial detection. The initial detection may occur five to ten seconds after onset of the potential RV lead dislodgment, for example. In some examples, IMD 10 may determine a patient risk level of patient 14. For example, IMD 10 may determine the patient risk level based on user, e.g., clinician input. In some examples, based on the patient risk level, IMD 10 determines whether to send an emergency alert in response to detecting potential RV lead dislodgement. For example, IMD 10 may determine the patient is high risk, and based on the determination that the patient is high risk and the determination of potential RV lead dislodgement, IMD 10 may initiate communication with computing devices 12 to send an emergency alert. In some examples, in addition to or alternatively to determining a patient risk level based on clinician input, IMD 10 may determine whether the underlying heart rate of patient 14 is below a threshold.

[0051] For example, IMD 10 may determine whether an underlying heart rate of patient 14 is below a threshold heart rate value, e.g., 30 bpm. IMD 10 may determine the underlying heart rate of patient 14 periodically, e.g., weekly, monthly, or during clinic visits. IMD 10 may determine the underlying heart rate of patient 14 in response to determining the potential RV lead dislodgement, e.g., via one or computing device(s) 12 or via IMD 10. In some examples, e.g., in examples in which IMD 10 identifies potential loss of capture, IMD 10 may temporarily withhold pacing, e.g., withhold pacing for 2 to 6 seconds, to determine the underlying heart rate. In some examples, IMD 10 may sense a far-field ventricular sensing vector to determine the underlying heart rate. In some examples, IMD 10 may be configured to select for far-field ventricular sensing, e.g., far- field sensing of R- waves in the ventricular sensing vector. The far-field R-waves may have lower frequency content than near-field P-waves that may be being oversensed. IMD 10 may be configured to filter the signal using a lowpass or bandpass filter to facilitate sensing the far-field R-waves. In some examples, determining the underlying heart rate using a far-field VEGM may improve an accuracy of the determination. For example, if the patient is experiencing AF and the RV lead has dislodged into the RA, the VEGM may sense an artificially high heart rate.

[0052] If the patient heart rate is below the threshold heart rate value, IMD 10 may initiate communication with computing device(s) 12. Initiating communication with computing device(s) 12 in response to an initial detection may facilitate theAtly Ref. No.: A0012234W001 communication being established in a timely manner. In some examples to conserve power of IMD 10 and computing device(s) 12, IMD 10 may wait to send the emergency alert, e.g., including sensed data associated with the potential RV lead dislodgment, until patient 14 confirms the emergency alert. In examples in which IMD 10 determines the patient risk level, IMD 10 may determine whether to send the emergency alert based on the patient risk level. In some examples, if the patient risk level is high, IMD 10 may determine to send the emergency alert. If the patient risk level is low, IMD 10 may determine to send a non-emergency alert. In examples in which IMD 10 determines the underlying heart rate of the patient, IMD 10 may send the emergency alert when the underlying heart rate of patient 14 is below the threshold and may send a non-emergency alert when the underlying heart rate of patient 14 is above the threshold. Conserving power may be significant in the case of non-rechargeable IMDs to prolong their life prior to needing replacement, e.g., surgical replacement, as well as for rechargeable IMDs or external devices to reduce recharge frequency.

[0053] In response to the message from IMD 10, computing device(s) 12 may output an alarm that may be visual and / or audible, and configured to immediately attract the attention of patient 14 or any person in environment 280 with patient 14, e.g., a bystander 260. Additionally, or alternatively, computing device(s) 12 may transmit an alert or alarm message to devices and users outside the visible / audio range of computing device(s) 12, e.g., to loT devices 230, bystander computing device 242, or computing system(s) 200. An alert or alarm message sent to computing system(s) 200 via network 260, or other messages sent by computing device(s) 12, may include the data received from IMD 10 and, in some cases, additional data collected by computing device(s) 12 or other devices in response to the detection of the potential RV lead dislodgment by IMD 10. For example, the message may include a location of patient 14 determined by computing device(s) 12. In some examples, computing device(s) 12 may further configure or change the content of alert or alarm messages based on the location of patient 14, e.g., different messages may be sent depending on whether patient 14 is at home, another residence, an office or business, a public location, or in a health care facility. The health care needed by patient, and thus the messaging of system 2, may vary depending on the location of patient 14.

[0054] Other devices in the environment 280 of patient 14 may also be configured to output alarms or take other actions to attract the attention of patient 14 and, possibly, aAtly Ref. No.: A0012234W001 bystander 226, or to otherwise facilitate the delivery of care to patient 14. For example, environment 280 may include one or more Internet of Things (loT) devices, such as loT devices 230A-230D (collectively “loT devices 230”) illustrated in the example of FIG. 2. loT devices 230 may include, as examples, so called “smart” speakers, cameras, televisions, lights, locks, thermostats, appliances, actuators, controllers, or any other smart home (or building) devices. In the example of FIG. 2, loT device 230C is a smart speaker and / or controller, which may include a display. loT devices 230 may provide audible and / or visual alarms when configured with output devices to do so. As other examples, loT devices 230 may cause smart lights throughout environment 280 to flash or blink and unlock doors. In some examples, loT devices 230 that include cameras, microphones, or other sensors may activate those sensors to collect data regarding patient 14, e.g., for evaluation of the condition of patient 14.

[0055] Computing device(s) 12 may be configured to wirelessly communicate with loT devices 230 to cause loT devices 230 to take the actions described herein. In some examples, processing circuitry 248 controls computing system 200A to communicate with loT devices 230 via network 260 to cause loT devices 230 to take the actions described herein, e.g., in response to receiving the alert message from computing device(s) 12 as described above. In some examples, IMD 10 is configured to communicate wirelessly with one or more of loT devices 230, e.g., in response to detection of a potential RV lead dislodgement when communication with external devices 12 is unavailable. In such examples, loT device(s) 230 may be configured to provide some or all of the functionality ascribed to external devices 12 herein.

[0056] Environment 280 includes computing facilities, e.g., a local network 232, by which external devices 12, loT devices 230, and other devices within environment 280 may communicate via network 260, e.g., with computing system(s) 200. For example, environment 280 may be configured with wireless technology, such as IEEE 802.11 wireless networks, IEEE 802.15 ZigBee networks, an ultra-wideband protocol, near-field communication, or the like. Environment 280 may include one or more wireless access points, e.g., wireless access points 234A and 234B (collectively, “wireless access points 234”) that provide support for wireless communications throughout environment 280. Additionally, or alternatively, e.g., when local network is unavailable, external devices 12, loT devices 230, and other devices within environment 280 may be configured toAtly Ref. No.: A0012234W001 communicate with network 260, e.g., computing system(s) 200, via a cellular base station 236 and a cellular network.

[0057] Computing device(s) 12, and in some examples loT device(s) 230, may include input devices and interfaces to allow a user to override the alarm in the event the detection of the potential RV lead dislodgment by IMD 10 was false. In some examples, the underlying heart rate threshold, e.g., the 30 bpm threshold, is a first underlying heart rate threshold, and if the underlying heart rate of patient 14 is below a second underlying heart rate threshold lower than the first underlying heart rate threshold, e.g., 15 bpm, IMD 10 may bypass allowing a user, e.g., patient 14, to confirm or override the potential RV lead dislodgement. However, if the underlying heart rate of patient 14 is between the first underlying heart rate threshold and the second underlying heart rate threshold, e.g., if patient 14’s heart rate is between 15 bpm and 30 bpm, computing device(s) 12 and / or loT device(s) 230 may prompt patient 14 to confirm the potential RV lead dislodgement before sending the emergency alert to additional devices and / or users, such as EMS.

[0058] Environment 280 may be a home, office, or place of business, or public venue, as examples. In some examples, one or more of computing device(s) 12 and loT device(s) 230 may implement an event assistant. The event assistant may provide a conversational interface for patient 14 and / or bystander 226 to exchange information with the computing device or loT device. The event assistant may query the user regarding the condition of patient 14 in response to receiving the alert message from IMD 10. Responses from the user may be used to confirm or override detection of the potential RV lead dislodgment by IMD 10, or to provide additional information about the potential RV lead dislodgment or the condition of patient 14 more generally that may improve the efficacy of the treatment of patient 14. For example, information received by the event assistant may be used to provide an indication of severity or type (differential diagnosis) for the potential RV lead dislodgment. The event assistant may use natural language processing and context data to interpret utterances by the user. In some examples, in addition to receiving responses to queries posed by the assistant, the event assistant may be configured to respond to queries posed by the user. For example, patient 14 may indicate that they feel dizzy and ask the event assistant, “how am I doing?”.

[0059] In some examples, computing device(s) 12 and / or computing system(s) 200 may implement one or more algorithms to evaluate the sensed physiological data, e.g., theAtty Ref. No.: A0012234W001VEGM, received from IMD 10, and in some cases additional physiological or other patient parameter data sensed or otherwise collected by the computing device(s) or loT devices 230, to confirm or override the detection of the potential RV lead dislodgement by IMD 10. In some examples, computing device(s) 12 and / or computing system(s) 200 may have greater processing capacity than IMD 10, enabling more complex analysis of the data. In some examples, the computing device(s) 12 and / or computing system(s) 200 may apply the data to a machine learning model or other artificial intelligence developed algorithm, e.g., to determine whether the data is sufficiently indicative of the potential RV lead dislodgment.

[0060] In examples in which computing device(s) 12 are configured perform a potential RV lead dislodgment confirmation analysis, computing device(s) 12 may transmit alert messages to computing system(s) 200 and / or loT devices 230 in response to confirming the potential RV lead dislodgment. In some examples, computing device(s) 12 may be configured to transmit the alert messages prior to completing the confirmation analysis and transmit cancellation messages in response to the analysis overriding the detection of the potential RV lead dislodgment by IMD 10. Processing circuitry 248 of computing system 200A may be configured to perform a number of operations in response to receiving an alert message from computing device(s) 12 and / or loT device(s) 230. Processing circuitry 248 of computing system 200A may be configured to cancel such operations in response to receiving a cancellation message from computing device(s) 12 and / or loT device(s) 230.

[0061] For example, computing system 200A may be configured to transmit alert messages to one or more computing devices 238 associated with one or more care providers 240 via network 260. Care providers may include EMS and hospitals, and may include particular departments within a hospital, such as an emergency department, catheterization lab, or a stroke response department. Computing devices 238 may include smartphones, desktop, laptop, or tablet computers, or workstations associated with such systems or entities, or employees of such systems or entities. The alert messages may include any of the data collected by IMD 10, computing device(s) 12, and loT device(s) 230, including sensed physiological data, e.g., VEGM data, AEGM data, time of the potential RV lead dislodgment, location of patient 14, and results of the analysis by IMD 10, computing device(s) 12, loT device(s) 230, and / or computing system(s) 200. TheAty Ref. No.: A0012234W001 information transmitted from computing system(s) 200 to care providers 240 may improve the timeliness and effectiveness of treatment of the potential RV lead dislodgment of patient 14 by care providers 240. In some examples, instead of or in addition to computing system(s) 200 providing an alert message to one or more computing devices 238 associated with an EMS care provider 240, computing device(s) 12 and / or loT devices 230 may be configured to automatically contact EMS, e.g., autodial 911, in response to receiving an alert message from IMD 10. Again, such operations may be confirmed or cancelled by patient 14, bystander 226, or another user via a user interface of computing device(s) 12 or loT device(s) 230, or automatically cancelled by computing device(s) 12 based on a confirmatory analysis performed by the computing device(s) overriding the detection of the potential RV lead dislodgment by IMD 10. However, in some examples, if the patient risk level meets a criterion, e.g., if the patient risk is higher than a threshold risk level and / or if the underlying heart rate of patient 14 is below the second underlying heart rate threshold, e.g., at or below 15 bpm, the user and / or computing device(s) 12 may not be able to cancel sending the alert to EMS.

[0062] Similarly, computing system(s) 200 may be configured to transmit an alert message to computing device 242 of bystander 226, which may improve the timeliness and effectiveness of treatment of the potential RV lead dislodgment of patient 14 by bystander 226. Computing device 242 may be similar to external devices 12 and computing devices 238, e.g., a smartphone. In some examples, computing system(s) 200 may determine that bystander 226 is proximate to patient 14 based on a location of patient 14, e.g., received from computing device(s) 12, and a location of computing device 242, e.g., reported to computing system(s) 200 by an application implemented on computing device 242. In some examples, computing system(s) 200 may transmit the alert message to any computing devices 242 in an alert area determined based on the location of patient 14, e.g., by transmitting the alert message to all computing devices in communication with base station 236, using any of the networking methods described herein.

[0063] In some examples, the alert message to bystander 226 may be configured to assist a layperson in treating patient. For example, the alert message to bystander 226 may include a location (and in some cases a description) of patient 14, the general nature of the potential RV lead dislodgment or other acute health event, directions for providing care to patient 14, such as directions for providing cardio-pulmonary resuscitation (CPR), aAtly Ref. No.: A0012234W001 location of nearby medical equipment for treatment of patient 14, such as an automated external defibrillator (AED) 44 or life vest, and instructions for use of the equipment. In some examples, computing device(s) 12, loT device(s) 230, and / or computing device 242 may implement an event assistant configured to use natural language processing and context data to provide a conversational interface for bystander 42. The assistant may provide bystander 226 with directions for providing care to patient 14 and respond to queries from bystander 226 about how to provide care to patient 14.

[0064] In some examples, computing system(s) 200 may mediate bi-directional audio (and in some cases video) communication between care providers 240 and patient 14 or bystander 226. Such communication may allow care providers 240 to evaluate the condition of patient 14, e.g., through communication with patient 14 or bystander 226, or through use of a camera or other sensors of the computing device or loT device, in advance of the time they will begin caring for the patient, which may improve the efficacy of care delivered to the patient. Such communication may also allow the care providers to instruct bystander 242 regarding first responder treatment of patient 14.

[0065] In some examples, computing system(s) 200 may control dispatch of a drone 246 to environment 280, or a location near environment 280 or patient 14. Drone 246 may be a robot and / or unmanned aerial vehicle (UAV). Drone 246 may be equipped with a number of sensors and / or actuators to perform a number of operations. For example, drone 246 may include a camera or other sensors to navigate to its intended location, identify patient 14 and, in some cases, bystander 226, and to evaluate a condition of patient. In some examples, drone 246 may include user interface devices to communicate with patient 14 and / or bystander 226. In some examples, drone 246 may provide directions to bystander 226, to the location of patient 14 and regarding how to provide first responder care, such as CPR, to patient 14. In some examples, drone 246 may carry medical equipment, e.g., AED 244, and / or medication to the location of patient 14.

[0066] Any of IMD 10, computing device(s) 12, loT device(s) 230, computing device(s) 238 and 242, AED 244, drone 246, or computing system(s) 200 may, individually or in any combination, perform the operations described herein for detection of potential RV lead dislodgment, by applying rules, which may include one or more machine learning models, to patient parameter data to detect potential RV lead dislodgment.Atly Ref. No.: A0012234W001

[0067] FIG. 3 is a block diagram illustrating an example configuration of IMD 10, in accordance with one or more techniques of this disclosure. IMD 10 is an example of a medical device that may be connected to implantable medical lead(s), but other medical devices, e.g., an external pacing system analyzer, may similarly be connected to implantable medical lead(s) and perform techniques of this disclosure. In examples in which IMD system 8 includes an external pacing system analyzer, the external pacing system analyzer may be configured substantially similarly to IMD 10.

[0068] In the illustrated example, IMD 10 includes memory 314, processing circuitry 302, sensing circuitry 304, therapy delivery circuitry 306, communication circuitry 318, and power source 310, one or more of which may be disposed within a housing of IMD 10. Power source 310 provides operational power for processing circuitry 302, sensing circuitry 304, sensor(s) 312, communication circuitry 318, memory 314, and therapy delivery circuitry 306.

[0069] In the example of FIG. 3, IMD 10 may also include one or more sensor(s) 312, such as an accelerometer, a blood pressure sensor, e.g., an optical sensor, and / or a pressure sensor. In some examples, memory 314 includes computer-readable instructions that, when executed by processing circuitry 302, cause IMD 10 and processing circuitry 302 to perform various functions attributed to IMD 10 and processing circuitry 302 herein. Memory 314 may include any volatile, non-volatile, magnetic, optical, or electrical media, such as a random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), electrically-erasable programmable ROM (EEPROM), flash memory, or any other digital media.

[0070] Processing circuitry 302 may include one or more of a microprocessor, a controller, digital signal processing circuitry (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or equivalent discrete or integrated logic circuitry. In some examples, processing circuitry 302 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, as well as other discrete or integrated logic circuitry. The functions attributed to processing circuitry 302 herein may be implemented as software, firmware, hardware or any combination thereof. Processing circuitry 302 may control therapy delivery circuitry 306 to deliver pacing to heart 23 of patient 14.Atty Ref. No.: A0012234W001

[0071] In some examples, processing circuitry 302 may be configured to determine potential RV lead dislodgement based on one or more of a correlation between an AEGM and a VEGM, e.g., a correlation of the timing and / or duration of waveforms of the AEGM and the VEGM, detection of atrial activity in a VEGM signal, a change in impedance, a change in R-wave amplitude, a change in P-wave amplitude, and / or a change in PCT and / or a signal indicative of loss of capture, e.g., relatively high amplitude pacing or a shock indicating a relatively high capture threshold or a complete loss of capture. In some examples, processing circuitry 302 initially determines the potential RV lead dislodgement based on a detection of atrial activity in the VEGM signal and in response, determines whether there is a change in impedance, a change in P-wave amplitude, a change in PCT or loss of capture, or a change in R-wave amplitude. In some examples, processing circuitry 302 initially determines the potential RV lead dislodgement based on a detection of a change in impedance.

[0072] In some examples, detecting atrial activity in the VEGM can include determining that the RV lead is sensing an atrial fibrillation (AF) episode and distinguishing AF sensed on the RV lead from a VF episode. In some examples, processing circuitry 302 detects the atrial activity in the VEGM. In some examples, external device 12 and / or computing system 200A detects the atrial activity in the VEGM. In some examples, processing circuitry 302 implements a machine learning model to detect the atrial activity in the VEGM.

[0073] Detecting atrial activity in the VEGM can additionally or alternatively include checking for cross-chamber oversensing (CCOS). In some examples, processing circuitry 302 determines CCOS is present, which is indicative of atrial activity in the VEGM and potential RV lead dislodgement by determining if ventricular sensed events consistently occur within a threshold period of time, e.g., 80 milliseconds, before or after atrial sensed events and / or atrial paced events. To determine if ventricular sensed events and atrial sensed events consistently occur within the threshold period of time, processing circuitry 302 may compare the VEGM to the AEGM to determine a correlation between the timings of the sensed events. If CCOS is present, processing circuitry 302 may determine the RV lead has potentially dislodged.

[0074] In some examples, to determine CCOS is present, processing circuitry 302 may determine AV intervals. If the AV intervals periodically or permanently switch from aAtty Ref. No.: A0012234W001 baseline value, e.g., 120 milliseconds, to a smaller value, e.g., less than 80 milliseconds, processing circuitry 302 may determine the AV intervals are indicative of potential RV lead dislodgement. The AV intervals may become smaller when the RV lead has dislodged and is sensing mostly atrial activity.

[0075] Detecting atrial activity in the VEGM can additionally or alternatively include processing circuitry 302 controlling therapy delivery circuitry 306 to administer atrial pacing. If processing circuitry 302 detects the atrial pacing in the VEGM, processing circuitry 302 may determine potential RV lead dislodgement. To detect atrial pacing in the VEGM, processing circuitry 302 may determine if the administered atrial pacing appears in the VEGM signal.

[0076] As another example, processing circuitry 302 may detect atrial pacing in the VEGM by identifying atrial pacing spikes in the ventricular sensing channel. If processing circuitry 302 identifies one or more atrial pacing spikes in the ventricular sensing channel, processing circuitry 302 may determine potential RV lead dislodgement.

[0077] Additionally, in some examples, processing circuitry 302 may determine whether an amplitude of P-waves, e.g., far-field VEGM P-waves, increased relative to a baseline amplitude by a threshold amount. In some examples, if the P-wave amplitudes increased by the threshold amount, processing circuitry 302 may determine potential RV lead dislodgement, e.g., RV lead dislodgement into the RA.

[0078] In some examples, detecting a change in R-wave amplitude can include determining whether an amplitude of R- waves decreased relative to a baseline amplitude by a threshold amount. In some examples, if the R-wave amplitudes decreased by the threshold amount, processing circuitry 302 may determine potential RV lead dislodgement.

[0079] In some examples, determining the change in impedance can include determining whether the impedance changed relative to a baseline impedance by a threshold amount. Processing circuitry 302 may determine potential RV lead dislodgement in response to determining the impedance changed by the threshold amount.

[0080] In some examples, detecting a change in PCT can include determining whether a PCT changed relative to a baseline amplitude by a threshold amount. In some examples, if the PCT changed by the threshold amount, processing circuitry 302 may determine potential RV lead dislodgement. In some examples, the change in PCT feature may beAty Ref. No.: A0012234W001 indicative of loss of capture. To determine loss of capture, processing circuitry 302 detects responses evoked by a stimulus. If processing circuitry 302 determines the capture threshold is relatively high, e.g., higher than expected when the RV lead is in contact with RV tissue, processing circuitry 302 may determine the RV lead has dislodged. In some examples, if the RV lead has fully dislodged into the right atrium of patient 14, the RV lead may capture atrial tissue. Therefore, in some examples, a dislodged RV lead may still appear to capture.

[0081] In some examples, processing circuitry 302 determines an underlying heart rate of patient 14, e.g., a heart rate of patient 14 or a heart rate variation of patient 14. In some examples, e.g., in examples in which processing circuitry 302 determines the one or more physiological signals are indicative of loss of capture, processing circuitry 302 determines to withhold pacing to determine the underlying heart rate in response to determining potential RV lead dislodgement. In some examples, e.g., in examples in which sensing circuitry 304 is able to sense accurately despite the potential RV lead dislodgement and the VEGM includes R- waves, to determine the underlying heart rate of patient 14, processing circuitry 302 determines timing between subsequent ventricular sensed events, e.g., in examples in which ventricular pacing is being withheld). If the VEGM additionally includes P-waves, processing circuitry 302 may differentiate between P-waves and R- waves by determining a threshold value associated with P-waves and a threshold value associated with R- waves. Processing circuitry 302 determines ventricular sensed events meeting or exceeding the R-wave threshold are R- waves. Processing circuitry 302 determines the time between the R-waves to determine a heart rate of patient 14.

[0082] In some examples, e.g. in examples in which sensing circuitry 304 is not sensing R-waves, to determine the underlying heart rate of patient 14, processing circuitry 302 controls sensing circuitry 304 to switch from bipolar sensing to unipolar sensing. Processing circuitry 302 identifies signals with similar amplitudes to differentiate between P-waves and R-waves. Processing circuitry 302 determines timing between the R-waves to determine the heart rate of patient 14.

[0083] In some examples, in addition to or alternatively to determining the underlying heart rate of patient 14 based on the VEGM, processing circuitry 302 determines whether hemodynamics of patient 14 may be compromised, e.g., due to RV lead dislodgement, based on one or more of a blood pressure (BP) signal, which sensing circuitry 304 mayAty Ref. No.: A0012234W001 sense via an optical sensor of sensor(s) 312 or an accelerometer signal, which sensing circuitry 303 may sense via an accelerometer of sensor(s) 312. In some examples, processing circuitry 302 determines patient 14’s heart rate by communicating with, as an example, computing device 12B of FIG. 2, which may comprise a smart watch capable of determining the heart rate of patient 14. In some examples, if processing circuitry 302 determines the BP of patient 14 is low or has changed by a threshold amount, processing circuitry 302 determines the BP of patient 14 is indicative of the potential RV lead dislodgement. In some examples, processing circuitry 302 may determine a risk level of patient 14 based on the BP of patient 14 in addition to or alternatively to determining the risk level of patient 14 based on user input and / or the underlying heart rate of patient 14.

[0084] In some examples, processing circuitry 302 determines the underlying heart rate periodically, e.g., monthly and / or during clinic visits. Processing circuitry 302 may store the underlying heart rate and may determine whether to send an emergency alert in response to determining potential RV lead dislodgement based on a comparison between the underlying heart rate and one or more thresholds.

[0085] In some examples, in addition to or alternatively to determining whether to send the emergency alert based on the underlying heart rate, processing circuitry 302 may determine a patient risk level of patient 14. In some examples, processing circuitry 302 determines the patient risk level based on user input, e.g., clinician input, indicative of the patient risk level. In some examples, the patient risk level is based at least in part on the underlying heart rate of the patient. In some examples, the patient risk level is based on one or more additional conditions of patient 14. Based on the patient risk level, processing circuitry 302 determines whether to send an emergency alert in response to determining potential RV lead dislodgement.

[0086] In some examples, processing circuitry 302 adjusts monitoring of patient 14 based on the patient risk level. As an example, if patient 14 is high risk, processing circuitry 302 may may sense physiological signals, e.g., impedance signals, and / or analyze features of the physiological signals more frequently than if patient 14 is low risk.

[0087] Sensing circuitry 304 is configured to monitor signals from at least one of electrodes 316 in order to monitor activity of heart 124, e.g., via cardiac EGM signals, such as VEGM signals, and / or impedance signals. Electrodes 316 may correspond to electrodes on one or more of leads 20, 21 and / or one or more electrodes on a housing ofAtly Ref. No.: A0012234W001IMD 10. In some examples, sensing circuitry 304 includes switching circuitry (not depicted) to select which of the available electrodes are used to sense the activity of heart 23. For example, processing circuitry 302 may select the electrodes that function as sense electrodes via the switching circuitry within sensing circuitry 304, e.g., by providing signals via a data / address bus. In some examples, sensing circuitry 304 includes one or more sensing channels, each of which may comprise an amplifier. In response to the signals from processing circuitry 302, the switching circuitry of sensing circuitry 304 may couple the outputs from the selected electrodes to one of the sensing channels. Sensing circuitry 304 may include impedance sensing circuitry, which may receive signals from one or more of electrodes 316 indicative of impedance.

[0088] Signals from the sensing electrodes may be converted to multi-bit digital signals by an anal og-to-digi tai converter for storage in memory 314. Processing circuitry 302 may employ digital signal analysis techniques to characterize the digitized signals stored in memory 314 to detect and classify the patient's heart rate from the signals. Processing circuitry 302 may detect and classify the heart rate of patient 4 by employing any of the numerous signal processing methodologies known in the art.

[0089] In some examples, IMD 10 may include one or more additional sensor(s) 312, such as accelerometers and / or temperature sensors. In some examples, accelerometers may comprise one or more three-axis accelerometers. Processing circuitry 302 may determine patient parameter values based on the signals obtained therefrom. As an example, processing circuitry 302 may determine a patient activity level and / or a patient posture. In some examples, if the patient activity level falls below a threshold, processing circuitry 302 may determine that the patient activity level is indicative of the potential RV lead dislodgement. As another example, processing circuitry 302 may determine whether patient 14 has fallen based on the accelerometer signal. If patient 14 has fallen and processing circuitry 302 has identified potential RV lead dislodgement, processing circuitry 302 may determine to send an emergency alert. In some examples, the emergency alert may include an indication that patient 14 has fallen. In some examples, processing circuitry 302 may increase a priority level associated with the emergency alert if patient 14 has fallen. Furthermore, in some examples, processing circuitry 302 may use signals generated by accelerometers to sense specific cardiac events, such as atrial or ventricular contractions.Atly Ref. No.: A0012234W001

[0090] In the example of FIG. 3, therapy delivery circuitry 306 is electrically coupled to electrodes 316. Electrodes 316 may include one of more of the electrodes 22, 24, 26, 28, 42, and 44 of FIG. 1. Therapy delivery circuitry 306 is configured to administer cardiac pacing and / or anti-tachyarrhythmia pacing, e.g., cardioversion or defibrillation.

[0091] Therapy delivery circuitry 306 may include switching circuitry. Processing circuitry 302 may use the switching circuitry to select, e.g., via a data / address bus, which of the available electrodes are used to deliver pacing pulses or shocks. The switching circuitry may include a switch array, switch matrix, multiplexer, or any other type of switching device suitable to selectively couple energy to selected electrodes. In other examples, processing circuitry 302 may select a subset of electrodes 316 with which energy is delivered to heart 23 without switching circuitry.

[0092] Communication circuitry 318 may include any suitable hardware, firmware, software, or any combination thereof for communicating with another device, such as external device 12, another networked computing device, or another IMD or sensor. Under the control of processing circuitry 302, communication circuitry 318 may receive downlink telemetry from, as well as send uplink telemetry to external device 12. In addition, processing circuitry 302 may communicate with a networked computing device via an external device (e.g., external device 12) and a computer network, such as the Medtronic CareLink™ Network. Communication circuitry 318 may be configured to transmit and / or receive signals via inductive coupling, electromagnetic coupling, Near Field Communication (NFC), Radio Frequency (RF) communication, Bluetooth, Wi-Fi, or other proprietary or non-proprietary wireless communication schemes.

[0093] FIG. 4 is a block diagram illustrating an example configuration of external device 12 of FIG. 1, in accordance with one or more techniques of this disclosure. External device 12 is configured to communicate with any IMD (e.g., IMD 10) described herein, in accordance with one or more techniques of this disclosure. In some examples, external device 12 may be substantially similar to or the same as any of computing devices 12, loTs 230, or computing system(s) 200 in FIG. 2. In the example of FIG. 4, external device 12 includes processing circuitry 406, communication circuitry 408, user interface 404, power source 402, and memory 410.

[0094] Processing circuitry 406, in one example, may include one or more processors that are configured to implement functionality and / or process instructions for executionAtly Ref. No.: A0012234W001 within external device 12. For example, processing circuitry 406 may be capable of processing instructions stored in memory 410. Processing circuitry 406 may include, for example, microprocessors, DSPs, ASICs, FPGAs, GPUs, TPUs, or equivalent discrete or integrated logic circuitry, or a combination of any of the foregoing devices or circuitry. Accordingly, processing circuitry 406 may include any suitable structure, whether in hardware, software, firmware, or any combination thereof, to perform the functions ascribed herein to processing circuitry 406.

[0095] Communication circuitry 408 may include any suitable hardware, firmware, software or any combination thereof for communicating with another device, such as IMD 500. Under the control of processing circuitry 406, communication circuitry 408 may receive downlink telemetry from, as well as send uplink telemetry to, IMD 10, loT device(s) 230, computing system(s) 200, or any other device in system 2 of FIG. 2.

[0096] A user, such as a clinician or patient 14, may interact with external device 12 through user interface 404. User interface 404 includes a display (not shown), such as an LCD or LED display or other type of screen, with which processing circuitry 406 may present information related to IMD 10 (e.g., a detection of potential RV lead dislodgement). In addition, user interface 404 may include an input mechanism to receive input from the user. The input mechanisms may include, for example, any one or more of buttons, a keypad (e.g., an alphanumeric keypad), a peripheral pointing device, a touch screen, or another input mechanism that allows the user to navigate through user interfaces presented by processing circuitry 406 of external device 12 and provide input. In other examples, user interface 404 also includes audio circuitry for providing audible notifications, instructions or other sounds to patient 14, receiving voice commands from patient 14, or both. Memory 410 may include instructions for operating user interface 404 and for managing power source 402.

[0097] Power source 402 is configured to deliver operating power to the components of external device 12. Power source 402 may include a battery and a power generation circuit to produce the operating power. In some examples, the battery is rechargeable to allow extended operation. Recharging may be accomplished by electrically coupling power source 402 to a cradle or plug that is connected to an alternating current (AC) outlet. In addition, recharging may be accomplished through proximal inductive interaction between an external charger and an inductive charging coil within externalAty Ref. No.: A0012234W001 device 12. In other examples, traditional batteries (e.g., nickel cadmium or lithium-ion batteries) may be used. In addition, external device 12 may be directly coupled to an alternating current outlet to operate.

[0098] Memory 410 may be configured to store information within external device 12 during operation. In some examples, memory 410 may be referred to as a storage device and include computer-readable instructions that, when executed by processing circuitry 406, cause external device 12 and processing circuitry 406 to perform various functions attributed to external device 12 and processing circuitry 406 herein. Memory 410 may include any volatile, non-volatile, magnetic, optical, or electrical media, such as RAM, DRAM, SRAM, magnetic discs, optical discs, flash memories, ROM, NVRAM, EPROM, EEPROM, flash memory, or any other digital media. Memory 410 may also store data generated by sensing circuitry 304 of IMD 10, such as signals corresponding to indications of detections of potential RV lead dislodgements.

[0099] In examples in which external device 12 is a smart watch or other wearable device of patient 14, external device 12 may include sensing circuitry (not depicted) configured to sense one of more signals of patient 14, such as an underlying patient heart rate, e.g., a patient heart rate in the absence of pacing. In some examples, based on the patient heart rate sensed via the sensing circuitry of external device 12, processing circuitry 406 of external device 12 and / or processing circuitry 302 of IMD 10 may determine whether to send an emergency alert corresponding to the potential RV lead dislodgement. In some examples, in addition to or alternatively to external device 12 determining the underlying patient heart rate, another IMD, e.g., an IMD other than IMD 10, such as an insertable cardiac monitor (ICM), may determine the underlying patient heart rate. In some examples, IMD 10 determines the underlying patient heart rate, e.g., via a combination of electrodes including one or more housing electrodes 16.

[0100] FIG. 5 is a block diagram illustrating an example configuration of computing system 200 A of FIG. 2, in accordance with one or more techniques of this disclosure. In the illustrated example, computing system 200A includes processing circuitry 502 for executing applications 524 that include monitoring system 450 or any other applications described herein. Computing system 200A may be any component or system that includes processing circuitry or other suitable computing environment for executing software instructions and, for example, need not necessarily include one or moreAtly Ref. No.: A0012234W001 elements shown in FIG. 5 (e.g., input devices 504, communication circuitry 506, user interface devices 510, or output devices 512; and in some examples components such as storage device(s) 508 may not be co-located or in the same chassis as other components). In some examples, computing system 200A may be a cloud computing system distributed across a plurality of devices.

[0100] In the example of FIG. 5, computing system 200A includes processing circuitry 502, one or more input devices 504, communication circuitry 506, one or more storage device(s) 508, user interface (UI) device(s) 510, and one or more output devices 512. Computing system 200A, in some examples, further includes one or more application(s) 524 such as monitoring system 450, and operating system 516 that are executable by computing system 200A. Each of components 502, 504, 506, 508, 410, and 512 are coupled (physically, communicatively, and / or operatively) for inter-component communications. In some examples, communication channels 514 may include a system bus, a network connection, an inter-process communication data structure, or any other method for communicating data. As one example, components 502, 504, 506, 508, 510, and 512 may be coupled by one or more communication channels 514.

[0101] Processing circuitry 502, in one example, is configured to implement functionality and / or process instructions for execution within computing system 200A. For example, processing circuitry 502 may be capable of processing instructions stored in storage device(s) 508. Examples of processing circuitry 502 may include any one or more of a microprocessor, a controller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or equivalent discrete or integrated logic circuitry.

[0102] One or more storage device(s) 508 may be configured to store information within computing system 200A during operation. Storage device(s) 508, in some examples, is described as a computer-readable storage medium. In some examples, storage device(s) 508 is a temporary memory, meaning that a primary purpose of storage device(s) 508 is not long-term storage. Storage device(s) 508, in some examples, is described as a volatile memory, meaning that storage device(s) 508 does not maintain stored contents when the computer is turned off. Examples of volatile memories include random access memories (RAM), dynamic random access memories (DRAM), static random access memories (SRAM), and other forms of volatile memories known in the art. In someAtly Ref. No.: A0012234W001 examples, storage device(s) 508 is used to store program instructions for execution by processing circuitry 502. Storage device(s) 508, in one example, is used by software or applications 524 running on computing system 200A to temporarily store information during program execution.

[0103] Storage device(s) 508, in some examples, also include one or more computer- readable storage media. Storage device(s) 508 may be configured to store larger amounts of information than volatile memory. Storage device(s) 508 may further be configured for long-term storage of information. In some examples, storage device(s) 508 include nonvolatile storage elements. Examples of such non-volatile storage elements include magnetic hard discs, optical discs, floppy discs, flash memories, or forms of electrically programmable memories (EPROM) or electrically erasable and programmable memories (EEPROM).

[0104] Computing system 200A, in some examples, also includes communication circuitry 506 to communicate with other devices and systems, such as IMD 10 and external device 12 of FIG. 1, as well as other networked client external devices of various users. Communication circuitry 506 may include a network interface card, such as an Ethernet card, an optical transceiver, a radio frequency transceiver, or any other type of device that can send and receive information. Other examples of such network interfaces may include 3G and Wi-Fi radios.

[0105] Computing system 200A, in one example, also includes one or more user interface devices 410. User interface devices 410, in some examples, are configured to receive input from a user through tactile, audio, or video feedback. Examples of user interface devices(s) 410 include a presence-sensitive display, a mouse, a keyboard, a voice responsive system, video camera, microphone or any other type of device for detecting a command from a user. In some examples, a presence-sensitive display includes a touch- sensitive screen.

[0106] One or more output device(s) 512 may also be included in computing system 200A. Output device(s) 512, in some examples, is configured to provide output to a user using tactile, audio, or video stimuli. Output device(s) 512, in one example, includes a presence-sensitive display, a sound card, a video graphics adapter card, or any other type of device for converting a signal into an appropriate form understandable to humans or machines. Additional examples of output device(s) 512 include a speaker, a cathode rayAtly Ref. No.: A0012234W001 tube (CRT) monitor, a liquid crystal display (LCD), or any other type of device that can generate intelligible output to a user.

[0107] Computing system 200A may include operating system 516. Operating system 516, in some examples, controls the operation of components of computing system 200A. For example, operating system 516, in one example, facilitates the communication of one or more applications 524 and monitoring system 540 with processing circuitry 502, communication circuitry 506, storage device(s) 508, input devices 504, user interface devices 510, and output devices 512.

[0108] Applications 524 may also include program instructions and / or data that are executable by computing system 200A. Example application(s) 524 executable by computing system 200A may include monitoring system 540. Other additional applications not shown may alternatively or additionally be included to provide other functionality described herein and are not depicted for the sake of simplicity.

[0109] In accordance with the techniques of the disclosure, computing system 200A receives an alert and, optionally, data corresponding to a potential RV lead dislodgement and / or underlying patient heart rate or another health event sensed via IMD 10, via communication circuitry 506. Computing system 200A may receive the alert from IMD 10 or from external device 12. Processing circuitry 502 may store the data corresponding to the potential RV lead dislodgement or another health event in storage device(s) 508.

[0110] Monitoring system 540, as implemented by computing system 200A including processing circuitry 502 and storage device(s) 508, may review the potential RV lead dislodgement, and based on the review, provide additional information when contacting a clinician at a hospital and / or EMS, which may improve treatment efficacy. As an example, monitoring system 540 may provide an indication to EMS whether patient 14 is experiencing asystole, ventricular tachycardia, or ventricular fibrillation. Monitoring system 540 may utilize input devices 504, output devices 512, and / or communication circuitry 406 to direct episode data and / or sensing issue data to one or more human reviewers, e.g., via one or more graphical user interfaces presented on output devices 512 or other client external devices.[oni] To review the potential RV dislodgement data, processing circuitry 502 may apply the episode data and / or sensing issue data, e.g., physiological data 382, as inputs to the one or more machine learning models 542. Machine learning models 542 may beAtty Ref. No.: A0012234W001 configured to confirm the potential RV lead dislodgement and / or determine additional information regarding the RV lead dislodgement, such as an extent to which the RV lead has dislodged.

[0112] FIG. 6 is a graphical representation of a potential RV lead dislodgement, in accordance with one or more techniques of this disclosure. In some examples, the graphical representation of the potential RV lead dislodgement is an example of an atrial activity on the VEGM feature. VEGM 606 and AEGM 608 may be indicative of potential RV lead dislodgement. In some examples, processing circuitry of system 8, e.g., processing circuitry 302, may determine a baseline correlation between VEGM 606 and AEGM 608, e.g., a correlation between timings, durations, amplitudes, or other waveform characteristics of sensed events of VEGM 606 and AEGM 608, during normal conditions, e.g., when the RV lead is placed appropriately, and the patient is not experiencing a cardiac event. Processing circuitry 302 may determine a correlation between timings of sensed events of VEGM 606 and AEGM 608 continuously to monitor for potential RV lead dislodgement. Processing circuitry 302 may continuously compare the determined correlation to the baseline correlation to determine whether the RV lead has potentially dislodged.

[0113] In some examples, processing circuitry 302 may determine a threshold correlation based on the baseline correlation. As an example, processing circuitry 302 may determine that an 80 millisecond or less difference between the timing of sensed events in the VEGM and sensed and / or paced events in the AEGM is indicative of potential RV lead dislodgement for patient 14. Processing circuitry of another HMD implanted in another patient may determine that a 60 millisecond or less difference between the timing of sensed events in the VEGM and AEGM is indicative of potential RV lead dislodgement for that patient. In some examples, the clinician determines the correlation threshold for patient 14. In some examples, the threshold correlation is not patient-specific.

[0114] In some examples, processing circuitry 302 may control communication circuitry 318 to communicate with external device 12. In some examples, machine learning models 542 described with respect to computing system 200A may additionally or alternatively be implemented in an edge device, such as external device 12. In some examples, external device 12 may implement machine learning models 542 to determine the potential RV lead dislodgement.Atty Ref. No.: A0012234W001

[0115] VEGM 602 and atrial EGM 604 may seem indicative of a PVT episode or VF episode but may actually be indicative of an AF episode. If the RV lead dislodged, e.g., into the RA, the RA may be being sensed by VEGM 602. Processing circuitry 302 of IMD 10 may determine atrial electrical activity is actually contained in the VEGM, and therefore, that the RV lead has become dislodged, by comparing VEGM 602 and atrial EGM 604. For example, if VEGM 602 and atrial EGM 604 are substantially similar, e.g., within a threshold difference, as depicted in the graphical representation of FIG. 6, processing circuitry 302 may determine the potential RV lead dislodgement. In some examples, processing circuitry 302 may determine atrial activity has a higher amplitude than ventricular activity in VEGM 602, which may indicate that the RV lead has dislodged into the right atrium. In some examples, processing circuitry 302 may determine amplitudes of atrial activity are above a threshold amplitude to determine potential RV lead dislodgement into the right atrium.

[0116] In addition to determining whether VEGM 602 and atrial EGM 604 are substantially similar, processing circuitry 302 may determine potential RV lead dislodgement based on the duration and / or morphology of the apparent PVT or VF episode. For example, AF episodes and other atrial episodes, such as atrial tachycardia (AT) and atrial flutter (AFL), may generally occur more frequently or for longer periods of time and may present as faster rhythms than typical PVT or VF episodes. Thus, if the apparent PVT episodes or VF episodes occur more frequently than a threshold frequency, are longer than a threshold duration, or are faster than a rate threshold, processing circuitry 302 may determine the apparent PVT episodes or VF episodes are AF, AT, or AFL episodes and that the RV lead has dislodged. In some examples, if the device detects multiple PVT / VF episodes that occur within minutes or hours of each other and that last multiple hours or days, processing circuitry 302 may determine that the detected arrhythmia is atrial in origin and, therefore, that the RV lead has potentially dislodged.

[0117] In some examples, VEGM 1102 may occasionally, even when dislodged, still sense ventricular sense events, e.g., R-waves, but the morphology of the ventricular sensing events may be indicative of far-field sensing instead of near-field sensing, (i.e., the frequency content of the VEGM has decreased, replacing narrow R-waves with wider R- waves). This observation may also be indicative of potential RV lead dislodgement.Atty Ref. No.: A0012234W001

[0118] In some examples, the difference between the timing of sensed events in the VEGM and AEGM may fall within the threshold correlation due to a cardiac episode, such as atrioventricular nodal reentrant tachycardia (AVNRT) and not due to RV lead dislodgement. In some examples, processing circuitry 302 may be configured to differentiate between RV lead dislodgement and AVNRT by determining whether one or more of a premature ventricular contraction (PVC) or a premature atrial contraction (PAC) precedes the apparent tachycardia in the VEGM and the AEGM, respectively. If processing circuitry 302 determines that the apparent tachycardia is preceded by one or more of the PVC or the PAC, processing circuitry 302 may determine that patient 14 is experiencing AVNRT and not potential RV lead dislodgement.

[0119] As another example, processing circuitry 302 may be configured to differentiate between similarities in the sensed events of the VEGM and the AEGM that are caused by cardiac episodes, such as AVNRT, junctional escape rhythm, and junctional tachycardia, and similarities in the sensed events of the VEGM and the AEGM that are caused by RV lead dislodgement. In some examples, if processing circuitry 302 determines the atrial rate increased or decreased, e.g., increased or decreased by a threshold amount, simultaneously, e.g., near simultaneously, when the sensed events became similar, e.g., similar in timing, duration, and / or amplitude, processing circuitry 302 may determine the patient 14 is experiencing AVNRT, junctional escape rhythm, or junctional tachycardia and not potential RV lead dislodgement. If processing circuitry 302 determines the atrial rate did not change, e.g., if the atrial rate did not change to a threshold extent, when the sensed events became similar, processing circuitry 302 may determine patient 14 is experiencing potential RV lead dislodgement.

[0120] In some examples, processing circuitry 302 may additionally be configured to determine potential RV lead dislodgement based on one or more additional signals, e.g., one or more additional signals sensed via additional sensor(s) 312. As an examples, processing circuitry 302 may determine a blood pressure of patient 14. If processing circuitry 302 determines the systolic blood pressure, the diastolic blood pressure, and / or the mean blood pressure decreased by a threshold amount, processing circuitry 302 may determine the potential RV lead dislodgement. As another example, based on an accelerometer signal, processing circuitry 302 may determine changes in contractility, which may also be indicative of the potential RV lead dislodgement.Atty Ref. No.: A0012234W001

[0121] FIG. 7 is a flow chart illustrating an example operation for determining whether to generate an emergency alert in response to determining potential right ventricular (RV) lead dislodgement, in accordance with one or more techniques of this disclosure. Although the example operation of FIG. 7 is described with respect to processing circuitry 302 of IMD 10, the techniques of the example operation may be performed by another device of system 8 of FIG. 1 or system 2 of FIG. 2, such as external device 12. In some examples, processing circuitry of different devices may be used to collectively perform this technique in a distributed computing model.

[0122] Processing circuitry 302 determines one or more features of a physiological signal are indicative of potential RV lead dislodgement (702). In some examples, the physiological signal is one or more cardiac EGMs, e.g., AEGM and VEGM. In some examples, the physiological signal additionally or alternative includes an impedance signal. The one or more features may include one or more of an atrial activity in the VEGM feature, a change in PCT, a change in R-wave amplitude feature, or a change in impedance feature. In some examples, to determine the one or more features of the physiological signal are indicative of potential RV lead dislodgement, processing circuitry 302 may compare the features to one or more thresholds. In some examples, to determine one or more of the one or more features, processing circuitry 302 may control therapy delivery circuitry 306 to administer pacing or another stimulus to invoke responses, or to withhold pacing therapy temporarily to determine the underlying intrinsic heart rate.Processing circuitry 302 may determine the one or more of the one or more features based on an analysis of the responses.

[0123] Detecting atrial activity in the VEGM can include checking for cross-chamber oversensing (CCOS). In some examples, processing circuitry 302 determines CCOS is present, which is indicative of atrial activity in the VEGM and potential RV lead dislodgement by determining if ventricular sensed events consistently occur within a threshold period of time, e.g., 80 milliseconds, before or after atrial sensed events and / or atrial paced events. If CCOS is present, processing circuitry 302 may determine the RV lead has potentially dislodged. Processing circuitry 302 may determine CCOS is present when a threshold number, e.g., 15-20, ventricular sensed events occurred within 80 milliseconds of atrial sensed events and / or atrial paced events. In some examples, theAtty Ref. No.: A0012234W001 threshold number may be patient specific. In some examples, the threshold number may be based on a patient risk level.

[0124] In some examples, detecting atrial activity in the VEGM can additionally or alternatively include determining that the RV lead is sensing an AF episode and distinguishing AF sensed on the RV lead from a VF episode, as discussed with respect to FIG. 6. In some examples, processing circuitry 302 detects the atrial activity in the VEGM. In some examples, external device 12 and / or computing system 200A detects the atrial activity in the VEGM. In some examples, processing circuitry 302 implements a machine learning model to detect the atrial activity in the VEGM.

[0125] Detecting atrial activity in the VEGM can additionally or alternatively include processing circuitry 302 controlling therapy delivery circuitry 306 to administer atrial pacing. If processing circuitry 302 detects the atrial pacing in the VEGM, processing circuitry 302 may determine potential RV lead dislodgement. In some examples, detecting the atrial pacing in the VEGM includes determining the morphology and / or amplitude of the response to the atrial pacing in the VEGM is similar to the morphology and / or amplitude of the response to the atrial pacing in the AEGM, e.g., within a threshold similarity.

[0126] As another example, processing circuitry 302 may detect atrial pacing in the VEGM by identifying atrial pacing spikes in the ventricular sensing channel. If processing circuitry 302 identifies one or more atrial pacing spikes in the ventricular sensing channel, processing circuitry 302 may determine potential RV lead dislodgement.

[0127] Additionally, in some examples, processing circuitry 302 may determine whether an amplitude of P-waves in the VEGM increased relative to a baseline amplitude by a threshold amount. In some examples, if the P-wave amplitudes increased by the threshold amount, processing circuitry 302 may determine potential RV lead dislodgement.

[0128] In some examples, detecting a change in R-wave amplitude can include determining whether an amplitude of R- waves decreased relative to a baseline amplitude by a threshold amount. In some examples, if the R-wave amplitudes decreased by the threshold amount, processing circuitry 302 may determine potential RV lead dislodgement.Atty Ref. No.: A0012234W001

[0129] In some examples, detecting a change in PCT can include determining whether a PCT changed relative to a baseline threshold by a threshold amount. In some examples, if the PCT changed by the threshold amount, processing circuitry 302 may determine potential RV lead dislodgement.

[0130] In some examples, the PCT feature may be indicative of loss of capture. To determine loss of capture, processing circuitry 302 detects responses evoked by a stimulus. If processing circuitry 302 determines the capture threshold is relatively high, e.g., higher than expected when the RV lead is in contact with RV tissue, processing circuitry 302 may determine the RV lead has dislodged. In some examples, if the RV lead has fully dislodged into the right atrium of patient 14, the RV lead may capture atrial tissue. Therefore, in some examples, a dislodged RV lead may still appear to capture. In some examples, the PCT may be higher than a highest possible output of IMD 10. In some examples, if processing circuitry 302 detects capture, but the capture threshold is higher than a threshold value, e.g., more than 4 Volts, processing circuitry 302 may determine to issue a non-emergency alert.

[0131] In some examples, determining the change in impedance amplitude can include determining whether the amplitude of the impedance changed relative to a baseline impedance amplitude by a threshold amount. Processing circuitry 302 may determine potential RV lead dislodgement in response to determining the impedance amplitude changed by at least the threshold amount.

[0132] Processing circuitry 302 may, in some examples, initially determine the atrial activity on the VEGM feature and, in response to the atrial activity on the VEGM feature being indicative of potential RV lead dislodgement, determine one or more additional features, such as an amplitude analysis of the VEGM and the AEGM, the change in impedance feature, the change in R-wave amplitude feature, the change in P-wave amplitude feature, or the change in PCT and / or loss of capture feature. Processing circuitry 302 may continuously monitor the VEGM and AEGM for CCOS by monitoring the correlation between timings of sensed events in the VEGM and AEGM. Processing circuitry 302 may additionally or alternatively monitor the VEGM and AEGM for CCOS by monitoring the correlation between amplitudes of sensed events in the VEGM and AEGM, as well as the correlation between other waveform characteristics.Aty Ref. No.: A0012234W001

[0133] In some examples, processing circuitry 302 may initially determine the change in R-wave amplitude feature and, in response to the R-wave amplitude feature being indicative of potential RV lead dislodgement, determine one or more additional features. In some examples, by determining one feature and responsively determining additional feature(s), the techniques of this disclosure may conserve battery life of IMD 10.

[0134] Responsive to the determination that one or more features of the physiological signal, e.g., the correlation between the VEGM and AEGM signals, are indicative of potential RV lead dislodgement, processing circuitry 302 may temporarily withhold pacing to measure the underlying heart rate, and compare the underlying heart rate of patient 14 to a threshold (704). In some examples, processing circuitry 302 determines the underlying heart rate of patient 14 in response to determining the potential RV lead dislodgement. In other examples, processing circuitry 302 continuously or periodically determines the underlying heart rate of patient 14, e.g., weekly, monthly, and / or during clinic visits.

[0135] In some examples, e.g., in examples in which sensing circuitry 304 is able to sense accurately, to determine the underlying heart rate of patient 14 in response to determining the potential RV lead dislodgement, processing circuitry 302 determines timing between subsequent ventricular sensed events. In some examples, sensing circuitry 304 may be able to sense accurately despite the potential RV dislodgement when the VEGM includes R-waves. Processing circuitry 302 may determine timings between subsequent ventricular sensed events in examples in which ventricular pacing is not being captured. If the VEGM additionally includes P-waves, processing circuitry 302 may differentiate between P-waves and R-waves by determining a threshold value associated with P-waves and a threshold value associated with R-waves. Processing circuitry 302 determines ventricular sensed events meeting or exceeding the R-wave threshold are R- waves. Processing circuitry 302 determines the time between the R-waves to determine a heart rate of patient 14.

[0136] In some examples, e.g. in examples in which sensing circuitry 304 is not sensing R-waves, to determine the underlying heart rate of patient 14, processing circuitry 302 controls sensing circuitry 304 to switch from bipolar sensing to unipolar sensing. Processing circuitry 302 identifies sensed events with similar amplitudes to differentiate between P-waves and R-waves. As an example, P-waves may all have an amplitude near aAty Ref. No.: A0012234W001 first amplitude value, and R-waves may all have an amplitude near a second amplitude value different from the first amplitude value. Processing circuitry 302 determines timing between the R-waves, e.g., the sensed events with amplitudes near the second amplitude value, to determine the heart rate of patient 14.

[0137] In some examples, e.g., in examples in which processing circuitry 302 is not able to determine the underlying heart rate of patient 14 using the techniques described above, processing circuitry 302 may determine to implement an artificial intelligence model to determine far-field R-waves. In some examples, if processing circuitry 302 is unable to determine the underlying heart rate, processing circuitry 302 determines to send the emergency alert, and processing circuitry 406 of external device 12 implements an artificial intelligence model to determine the far-field R-waves. Based on the time between the far-field R-waves, processing circuitry 406 may determine the underlying heart rate of patient 14. Processing circuitry 406 may generate for output an indication of a priority level based on the underlying heart rate of patient 14 and / or may output the underlying heart rate of patient 14 for user review.

[0138] In some examples, in addition to or alternatively to determining the underlying heart rate of patient 14 based on the VEGM, processing circuitry 302 determines whether hemodynamics of patient 14 may be compromised, e.g., due to RV lead dislodgement, based on one or more of a BP signal, which sensing circuitry 304 may sense via an optical sensor of sensor(s) 312 or an accelerometer signal, which sensing circuitry 303 may sense via an accelerometer of sensor(s) 312. In some examples, processing circuitry 302 determines a heart rate of patient 14 by communicating with, as an example, computing device 12B of FIG. 2, which may comprise a smart watch capable of determining the heart rate of patient 14.

[0139] In some examples, if processing circuitry 302 determines the BP of patient 14 is low and / or has dropped by a threshold amount, processing circuitry 302 may determine the BP is indicative of potential RV lead dislodgement. In some examples, based on the BP of patient 14, processing circuitry 302 may confirm that patient 14 is experiencing hemodynamic compromise. In some examples, processing circuitry 302 determines the risk level of patient 14 based on patient 14’ s BP in addition to or alternatively to determining the risk level of patient 14 based on user input and / or the underlying heart rate of patient 14.Aty Ref. No.: A0012234W001

[0140] Responsive to the underlying heart rate, of patient 14 meeting, e.g., falling below, a threshold, e.g., 20 bpm or 30 bpm, processing circuitry 302 determines to send an emergency alert to a user, e.g., EMS or hospital personnel (706). If the heart rate of patient 14 is greater than the threshold, processing circuitry 302 may determine to send a nonemergency alert to patient 14, a caretaker, and / or the clinician. In some examples, if patient 14 has been more than a threshold percentage ventricularly paced, e.g., more than 90% ventricularly paced since implant, within the past month, or some other time period, processing circuitry 302 may bypass comparing the underlying heart rate to the threshold and may send the emergency alert. In some examples, the clinician may determine whether processing circuitry 302 will compare the underlying heart rate to the threshold or may configure the threshold for patient 14.

[0141] FIG. 8 is a flowchart illustrating an example operation for determining to generate an emergency alert in response to determining potential RV lead dislodgement based on a physiological signal and a patient risk level, in accordance with one or more techniques of this disclosure. Although the example operation of FIG. 8 is described with respect to processing circuitry 302 of IMD 10, the techniques of the example operation may be performed by another device of system 8 of FIG. 1 or system 2 of FIG. 2, such as external device 12. In some examples, processing circuitry of different devices may be used to collectively perform this technique in a distributed computing model.

[0142] Processing circuitry 302 determines a patient is high risk based on one or more of a patient underlying heart rate or user input indicative of a patient risk level (802). In some examples, the patient’s underlying heart rate comprises a heart rate determined during a clinic visit or an otherwise periodically determined underlying heart rate. The user input may be clinician input. The clinician may, via a user interface of a device of system 2, such as via user interface device(s) 510 of computing system 200A, provide input indicative of the patient risk level. In some examples, the user input may include underlying heart rate information, an extent to which patient 14 is paced, or other indicators that RV lead dislodgement of the defibrillation lead may put patient 14 at high risk.

[0143] Processing circuitry 302 determines a feature of a physiological signal of patient 14, e.g., an atrial activity in a VEGM feature, is indicative of potential of RV lead dislodgement (804). In some examples, processing circuitry 302 may determine the atrialAtly Ref. No.: A0012234W001 activity in the VEGM is indicative of potential lead dislodgement when a threshold number of sensed events in the VEGM and AEGM meet a similarity threshold, e.g., a timing of sensed events meets a timing similarity threshold and / or an amplitude of sensed events meets an amplitude similarity threshold. In some examples, the threshold number may be patient specific. In some examples, the threshold number may be based on the patient risk level. As an example, for patients who are higher risk, the threshold number may be lower than for patients who are low risk. In some examples, the threshold number may be between 15 and 20 beats. In some examples, upon determining the atrial activity in the VEGM feature, processing circuitry 302 determines one or more additional features are indicative of potential RV lead dislodgment. Processing circuitry 302 may prompt patient 14 to confirm an emergency alert (806). In some examples, processing circuitry 302 may bypass prompting patient 14 to confirm the emergency alert.

[0144] In response to patient 14 confirming the emergency alert (“YES” of 808), processing circuitry 302 sends the emergency alert to a user, e.g., EMS. The emergency alert may include an indication of a patient condition or a recommended therapy for the patient. As an example, the emergency alert may include an indication that patient 14 is experiencing asystole and / or may provide an indication that pacing (e.g., transcutaneous or temporary pacing) is recommended. As another example, the emergency alert may include an indication that patient 14 is experiencing ventricular tachycardia or ventricular fibrillation and / or may provide an indication that defibrillation is recommended.

[0145] If the patient does not confirm the emergency alert (“NO” of 808), processing circuitry 302 determines whether patient 14 dismissed the alert (810). If patient 14 dismissed the alert (“YES” of 810), processing circuitry 302 may send a non-emergency alert indicating the potential lead dislodgement (814). In some examples, processing circuitry 302 may not send the non-emergency alert. If patient 14 did not dismiss the alert (“NO” of 810), processing circuitry 302 determines whether a threshold period of time has passed, e.g., 30 seconds (812). If processing circuitry 302 determines the threshold period of time has passed (“YES” of 812), processing circuitry 302 sends the emergency alert. If processing circuitry 302 determines the threshold period of time has not passed (“NO” of 812), processing circuitry 302 returns to checking whether the patient confirmed the alert (808). Processing circuitry 302 may continuously check whether the patient confirmed or dismissed the alert until the threshold period of time passes.Aty Ref. No.: A0012234W001

[0146] In some examples, processing circuitry 302 may be configured to perform a similar operation when processing circuitry 302 determines patient 14 is low risk. If patient 14 is low risk, processing circuitry may determine to send a non-emergency alert in response to determining the potential RV lead dislodgement. In some examples, processing circuitry 302 may bypass prompting patient 14 to confirm the non-emergency alert.

[0147] FIG. 9 is a flowchart illustrating an example operation for determining to generate an emergency alert in response to determining potential RV lead dislodgement based on a comparison between timings of atrial sensed events and ventricular sensed events and one or more additional features being indicative of the potential RV lead dislodgement, in accordance with one or more techniques of this disclosure. Although the example operation of FIG. 9 is described with respect to processing circuitry 302 of IMD 10 and processing circuitry 406 of external device 12, the techniques of the example operation may be performed by another device of system 8 of FIG. 1 or system 2 of FIG. 2. In some examples, processing circuitry of different devices may be used to collectively perform this technique in a distributed computing model.

[0148] Sensing circuitry, e.g., sensing circuitry 304 of IMD 10, senses a plurality of patient signals including an AEGM and a VEGM (902). Each of the VEGM and the AEGM may be one or more of a near-field or a far-field EGM signal. Based on a comparison of timings of atrial sensed events in the AEGM and ventricular sensed events in the VEGM meeting a similarity criterion, processing circuitry 302 may determine the comparison is indicative of potential RV lead dislodgement (904). In some examples, the similarity criterion comprises a correlation between timings of atrial sensed events and ventricular sensed events. As an example, processing circuitry 302 may determine the comparison is indicative of potential RV lead dislodgement if a threshold number of atrial sensed and / or paced events, e.g., 15 to 20 beats, and ventricular sensed events occur within a threshold amount of time, e.g., 80 milliseconds, of one another. The threshold number and the threshold amount of time may be patient specific and / or may be based on clinician input. In some examples, processing circuitry 302 additionally determines a risk level of patient 14. The risk level may be based on one or more of patient 14’ s underlying heart rate or clinician input. Based on the risk level, processing circuitry 302 may determine the threshold number and the threshold amount of time. In examples in which patient 14 isAtty Ref. No.: A0012234W001 pacer-dependent but ventricular pacing is inhibited, processing circuitry 302 may determine potential oversensing of the atrium.

[0149] Processing circuitry 302 may additionally determine to monitor additional physiological signals and / or physiological signal features more frequently in response to determining the risk level for patient 14 meets a criterion than if the risk level does not meet the criterion. As an example, if the risk level for patient 14 meets the criterion, e.g., if the risk level is high, processing circuitry 302 may determine one or more of a change in impedance feature, a change in R-wave amplitude feature, or a change in PCT feature on a periodic schedule. As an example, processing circuitry 302 may determine to determine impedance of patient 14 every 15 seconds if the risk level is high. If the risk level for patient 14 is low, processing circuitry 302 may determine the one or more of the change in impedance feature, the change in R-wave amplitude feature, or the change in PCT feature on another periodic schedule that includes less frequent monitoring of the one or more of the change in impedance feature, the change in R-wave amplitude feature, or the change in PCT feature. As an example, processing circuitry 302 may determine to determine impedance of patient 14 every 30 seconds, every two minutes, every ten minutes etc. Based on the determination that the comparison is indicative of potential RV lead dislodgement, processing circuitry 302 enters a “concerned state” in which processing circuitry 302 determines one or more features based on the plurality of patient signals (906). The one or more features may include, as examples, the change in impedance feature, the change in R-wave amplitude feature, a change in P-wave amplitude feature, or the change in PCT feature. In some examples, processing circuitry 302 may determine to temporarily slow down or pause pacing to take time to quantify an amount of atrial activity that appears on the VEGM. In some examples, processing circuitry 302 may determine to control therapy delivery circuitry 306 to deliver one or more of an early atrial pace or an early ventricular pace. Processing circuitry 302 may monitor the VEGM and determine, based on the morphology of the VEGM corresponding to the one or more of the early atrial pace or the early ventricular pace, whether the RV lead has potentially dislodged.

[0150] In some examples, processing circuitry 302 may determine the change in impedance feature. If the change in impedance feature is indicative of potential RV lead dislodgement, processing circuitry 302 may determine another feature, e.g., the change inAty Ref. No.: A0012234W001R-wave amplitude feature in response to the impedance feature being indicative of the potential RV lead dislodgement. Processing circuitry 302 may determine the change in PCT feature in response to the change in impedance feature and the change in R-wave amplitude feature being indicative of potential RV lead dislodgement.

[0151] If the one of more features are not indicative of potential RV lead dislodgement (“NO” of 908), processing circuitry 302 continues sensing the AEGM and the VEGM and exits the “concerned state” (902). If the one or more features are indicative of potential RV lead dislodgement (“YES” of 908), processing circuitry 302 may prompt patient 14 to confirm an emergency alert (910). In some examples, processing circuitry 302 may control communication circuitry 318 to communicate with external device 12. Processing circuitry 406 may control user interface 404 to present the prompt to the patient.

[0152] Processing circuitry 302 or processing circuitry 406 may continuously check for patient confirmation of the emergency alert prompt. If patient 14 confirms the emergency alert (“YES” of 912), processing circuitry 302 or processing circuitry 406 sends an emergency alert to a user, e.g., EMS (920). If patient 14 does not confirm the emergency alert (“NO” of 912), processing circuitry 302 or processing circuitry 406 checks whether patient 14 dismissed the emergency alert (914). If patient 14 dismissed the emergency alert (“YES” of 914), processing circuitry 302 or processing circuitry 406 may optionally send a non-emergency alert to the user, e.g., patient 14. If patient 14 did not dismiss the emergency alert (“NO” of 914), processing circuitry 302 or processing circuitry 406 determines whether a threshold period of time has passed, e.g., 30 seconds (916). In some examples, the threshold period of time is based on a patient risk level and / or clinician input. If the threshold period of time has passed (“YES” of 916), processing circuitry 302 or processing circuitry 406 sends the emergency alert to the user, e.g., EMS (920). If the threshold period of time has not passed (“NO” of 916), processing circuitry 302 or processing circuitry 406 continues to check for patient confirmation of the emergency alert (912).

[0153] In some examples, if patient 14 is low risk, processing circuitry may, in response to determining the features are indicative of potential RV lead dislodgement (“YES” of 908), determine to send a non-emergency alert to the user, e.g., patient 14 and / or the clinician.Atty Ref. No.: A0012234W001

[0154] FIG. 10 is a flowchart illustrating an example operation for determining whether to generate an emergency alert in response to determining potential RV lead dislodgement based on an underlying heart rate of a patient, in according with one or more techniques of this disclosure. The example operation of FIG. 10 can be a specific example of the example operation of FIG. 7. Although the example operation of FIG. 10 is described with respect to processing circuitry 302 of IMD 10, the techniques of the example operation may be performed by another device of system 8 of FIG. 1 or system 2 of FIG. 2, such as external device 12. In some examples, processing circuitry of different devices may be used to collectively perform this technique in a distributed computing model.

[0155] Sensing circuitry 304 senses a physiological signal, e.g., a cardiac EGM, such as a VEGM and / or an impedance signal, of a patient, e.g., patient 14 (1002). Processing circuitry 302 determines one or more features of the physiological signal is indicative of potential RV lead dislodgement (1004). The one or more features may include one or more of an atrial activity in the VEGM feature, a change in PCT feature, which may comprise a loss of capture feature, a change in R-wave amplitude feature, a change in P-wave amplitude feature, or a change in impedance feature. In some examples, to determine the one or more features of the physiological signal are indicative of potential RV lead dislodgement, processing circuitry 302 may compare the features to one or more thresholds. In some examples, to determine one or more of the one or more features, processing circuitry 302 may control therapy delivery circuitry 306 to administer pacing or another stimulus to invoke responses, or to temporarily withhold pacing to determine underlying rate. Processing circuitry 302 may determine the one or more of the one or more features based on an analysis of the responses.

[0156] In some examples, processing circuitry 302 may determine a first feature, e.g., the atrial activity in the VEGM feature and / or the change in R-wave amplitude feature, and in response to the first feature being indicative of potential RV lead dislodgement, processing circuitry 302 may determine one or more additional features, e.g., the change in impedance feature or the PCT feature. In some examples, the first feature may be less computationally expensive than the one or more additional features. By determining the first feature and responsively determining one or more additional features, the techniques of this disclosure may conserve battery power of IMD 10.Atly Ref. No.: A0012234W001

[0157] Processing circuitry 302 compares an underlying heart rate of patient 14 to a first threshold and a second threshold (1006). In some examples, the first threshold is larger than the second threshold. In some examples, processing circuitry 302 determines the underlying heart rate of patient 14 in response to determining the one or more features of the physiological signal(s) is indicative of potential RV lead dislodgement. In other examples, processing circuitry 302 continuously or periodically determines the underlying heart rate of patient 14. As an example, processing circuitry 302 may determine the underlying heart rate of patient 14 weekly, monthly, and / or during clinic visits. In some examples, another device, such as external device 12B or an ICM, determines the underlying heart rate of patient 14 continuously or periodically.

[0158] In examples in which processing circuitry 302 determines the underlying heart rate of patient 14 in response to determining the one or more features of the physiological signal(s) is indicative of potential RV lead dislodgement, processing circuitry 302 may control sensing circuitry to sense the VEGM of patient 14 to determine the underlying heart rate. In some examples, e.g., in examples in which sensing circuitry 304 is able to sense accurately despite the potential RV lead dislodgement and the VEGM includes R- waves, to determine the underlying heart rate of patient 14, processing circuitry 302 determines timing between subsequent ventricular sensed events, e.g., in examples in which ventricular pacing is not being captured). If the VEGM additionally includes P- waves, processing circuitry 302 may differentiate between P-waves and R- waves by determining a threshold value associated with P-waves and a threshold value associated with R- waves. Processing circuitry 302 determines ventricular sensed events meeting or exceeding the R-wave threshold are R-waves. Processing circuitry 302 determines the time between the R-waves to determine a heart rate of patient 14.

[0159] In some examples, e.g. in examples in which sensing circuitry 304 is not sensing R-waves, to determine the underlying heart rate of patient 14, processing circuitry 302 controls sensing circuitry 304 to switch from bipolar sensing to sensing. Processing circuitry 302 identifies sensed events with similar amplitudes to differentiate between P- waves and R-waves. Processing circuitry 302 determines timing between the R-waves to determine the heart rate of patient 14. As an example, P-waves may all have an amplitude near a first amplitude value, and R-waves may all have an amplitude near a second amplitude value different from the first amplitude value. Processing circuitry 302Atly Ref. No.: A0012234W001 determines timing between the R-waves, e.g., the sensed events with amplitudes near the second amplitude value, to determine the heart rate of patient 14.

[0160] In some examples, e.g., in examples in which processing circuitry 302 is not able to determine the underlying heart rate of patient 14 using the techniques described above, processing circuitry 302 may determine to implement an artificial intelligence model to determine far-field R-waves. In some examples, if processing circuitry 302 is unable to determine the underlying heart rate, processing circuitry 302 determines to send the emergency alert, and processing circuitry 406 of external device 12 implements an artificial intelligence model to determine the far-field R-waves. Based on the time between the far-field R-waves, processing circuitry 406 may determine the underlying heart rate of patient 14. Processing circuitry 406 may generate for output an indication of a priority level based on the underlying heart rate of patient 14 and / or may output the underlying heart rate of patient 14 for user review.

[0161] In some examples, in addition to or alternatively to determining the underlying heart rate of patient 14 based on the VEGM, processing circuitry 302 determines whether hemodynamics of patient 14 may be compromised, e.g., due to RV lead dislodgement, based on one or more of a BP signal, which sensing circuitry 304 may sense via an optical sensor of sensor(s) 312 or an accelerometer signal, which sensing circuitry 303 may sense via an accelerometer of sensor(s) 312. In some examples, processing circuitry 302 determines patient 14’ s heart rate by communicating with, as an example, computing device 12B of FIG. 2, which may comprise a smart watch capable of determining the heart rate of patient 14.

[0162] If the underlying heart rate exceeds the first threshold, e.g., 30 bpm, (“> FIRST THRESHOLD” of 1006), processing circuitry 302 generates a non-emergency alert (1016). In some examples, the non-emergency alert comprises a notification to patient 14 to seek medical attention or to make an appointment with a clinician. In some examples, processing circuitry 302 controls communication circuitry 318 to send the non-emergency alert to external device 12 for presentation via user interface 404 and / or sends the non- emergency alert to a caregiver device.

[0163] If the underlying heart rate falls within a range defined by the first threshold and the second threshold, e.g., if the underlying heart rate is between 15 bpm and 30 bpm, (“SECOND THRESHOLD < UNDERLYING HEART RATE < FIRST THRESHOLD”Atly Ref. No.: A0012234W001 of 1006), processing circuitry 302 determines to generate a prompt to a user, e.g., patient 14, to confirm sending an emergency alert (1008). In some examples, the first threshold is inclusive. For example, if the underlying heart rate is 30 bpm, processing circuitry 302 determines the underlying heart rate falls within the range defined by the first threshold and the second threshold. In some examples, processing circuitry 302 controls communication 318 to send the prompt to external device 12 for presentation to patient 14 via user interface 404 and / or sends the prompt to a caregiver of patient 14. In some examples, the prompt may indicate to the patient that IMD 10 detected potential RV lead dislodgement and prompts patient 14 to confirm or dismiss the alert.

[0164] If patient 14 confirms the alert or a threshold period of time passes without the patient dismissing the alert (“YES” of 1010), processing circuitry 302 generates the emergency alert (1014). In some examples, processing circuitry 302 controls communication circuitry 318 to communicate with external device 12 and / or any other devices of system 2 of FIG. 2. In some examples, sending the emergency alert comprises controlling a device, e.g., external device 12, to auto-dial 911 or to otherwise contact EMS.

[0165] If patient 14 does not confirm the alert and the threshold period of time has not been met (“NO” of 1010), processing circuitry 302 determines whether patient 14 has dismissed the alert (1012). If patient 14 dismissed the alert (“YES” of 1012), processing circuitry 302 generates a non-emergency alert. If patient 14 did not dismiss the alert (“NO” of 1012), processing circuitry 302 continues to check whether patient 14 confirmed the alert or the threshold period of time has passed (1010).

[0166] If the underlying heart rate of patient 14 is less than the second threshold, e.g.,15 bpm, (“< SECOND THRESHOLD” of 1006), processing circuitry 302 generates the emergency alert (1014). In some examples, the second threshold is inclusive. For example, if the underlying heart rate is 15 bpm, processing circuitry 302 determines the underlying heart rate of patient 14 is less than the second threshold. In some examples, if the underlying heart rate of patient 14 is less than the second threshold, the condition of patient 14 may be more severe than when the underlying heart rate of patient 14 is greater than the threshold. In some examples, processing circuitry 302 generates the emergency alert without first prompting patient 14 to confirm or dismiss the alert to facilitate faster alerting and treatment. In some examples, processing circuitry 302 prompts patient 14 toAtty Ref. No.: A0012234W001 confirm or dismiss the alert. In some examples, the threshold amount of time may be shorter for patients with underlying heart rates that fall below the second threshold than for patients with underlying heart rates between the first and second threshold. In some examples, the threshold amount of time is the same for patients with underlying heart rates that fall below the second threshold and patients with underlying heart rates between the first and second threshold. In some examples, the emergency alert includes an indication of patient 14’ s underlying heart rate.

[0167] In response to the underlying heart rate of patient 14 meeting, e.g., falling below, a threshold, e.g., 30 bpm, processing circuitry 302 determines to send an emergency alert to a user, e.g., EMS or hospital personnel. If the heart rate of patient 14 is greater than the threshold, processing circuitry 302 may determine to send a nonemergency alert to patient 14, a caretaker, and / or the clinician. In some examples, if patient 14 is more than a threshold percentage ventricularly paced, e.g., more than 90% ventricularly paced, processing circuitry 302 may bypass comparing the underlying heart rate to the threshold and may send the emergency alert. In some examples, the clinician may determine whether processing circuitry 302 will compare the underlying heart rate to the threshold or may configure the thresholds for patient 14.

[0168] FIG. 11 is a flow chart illustrating an example operation for determining whether a ventricular cardiac electrogram (VEGM) signal is indicative of ventricular lead migration, in accordance with one or more techniques of this disclosure. Although the example operation of FIG. 11 is described with respect to processing circuitry 302 of IMD 10, the techniques of the example operation may be performed by another device of system 8 of FIG. 1 or system 2 of FIG. 2, such as external device 12. In some examples, processing circuitry of different devices may be used to collectively perform this technique in a distributed computing model.

[0169] In some examples, the example operation of FIG. 11 is an example of determining one or more features of the physiological signal are indicative of potential RV lead dislodgement (702 of FIG. 7 and 804 of FIG. 8). Processing circuitry 302 controls therapy delivery circuitry 306 to deliver atrial pacing via atrial lead 21 of FIG. 1 (1102). In some examples, processing circuitry 302 controls therapy delivery circuitry 306 to deliver atrial pacing periodically. In some examples, processing circuitry 302 controls therapy delivery circuitry 306 to deliver atrial pacing in response to determining another one ofAtly Ref. No.: A0012234W001 more features of the physiological signal, e.g., the impedance signal or the VEGM, is indicative of potential RV lead dislodgement.

[0170] Processing circuitry 302 determines whether a VEGM corresponding to the atrial pacing is indicative of potential RV lead dislodgement (1104). In some examples, processing circuitry 302 determines the VEGM is indicative of potential RV lead dislodgement when the VEGM includes indicators of the atrial pacing. In some examples, if processing circuitry 302 determines the VEGM includes indicators of the atrial pacing, processing circuitry 302 may determine that the RV lead has potentially dislodged from the RV and migrated to the right atrium.

[0171] FIG. 12 is a conceptual diagram illustrating an example user interface of an external device, in accordance with one or more techniques of this disclosure. Although the example user interface of FIG. 12 is described with respect to external device 12, the example user interface may be a user interface of another device of system 8 of FIG. 1 or system 2 of FIG. 2, such as loT device 230A.

[0172] User interface 404 of external device 12 may, in response to IMD 10 and / or external device 12 determining potential RV lead dislodgement and determining to prompt patient 14 to confirm an emergency alert, display screen 1202. Screen 1202 may include lead dislodgement alert 1204. Screen 1202 may additionally include a confirm EMS alert button 1206 and a dismiss EMS alert button 1208. In some examples, lead dislodgement alert 1204 may prompt patient 14 to confirm the EMS alert if patient 14 is experiencing symptoms associated with RV lead dislodgement or otherwise prompt patient 14 to provide an indication of patient status. In some examples, lead dislodgement alert 1204 may include text, such as “POTENTIAL LEAD DISLODGEMENT DETECTED - CONFIRM EMS ALERT IF YOU ARE EXPERIENCING SYMPTOMS.”

[0173] In some examples, if patient 14 presses confirm EMS alert button 1206, user interface 404 may display a pop-up screen (not depicted) prompting patient 14 to confirm the selection before sending the emergency alert. If patient 14 does not confirm the selection within a threshold period of time, e.g., 5 seconds, external device 12 or IMD 10 sends the emergency alert. In some examples, user interface 404 does not display the popup screen, and external device 12 sends the emergency alert in response to patient 14 pressing confirm EMS alert button 1206.Atly Ref. No.: A0012234W001

[0174] In some examples, if patient 14 presses dismiss EMS alert 1208, user interface 404 may display a pop-up that patient screen (not depicted) prompting patient 14 to confirm the selection before canceling the emergency alert. If patient 14 does not confirm the selection within a threshold period of time, e.g., within the amount of time remaining indicating in a countdown display 1210, external device 12 may send the emergency alert. In some examples, user interface 404 may not display a pop-up screen before external device 12 cancels the emergency alert.

[0175] In some examples, if patient 14 does not press either of confirm EMS alert button 1006 or dismiss EMS alert button 1208 within a threshold period of time, e.g., 30 seconds, external device 12 sends the emergency alert. The threshold period of time may be a “timeout” period. If patient 14 is unable to respond the prompt due to symptoms associated with RV lead dislodgement, external device 12 sends the emergency alert. In some examples, screen 1202 includes a countdown display 1210 indicating an amount of time remaining before auto-sending the EMS alert.

[0176] Example 1. A system comprising: sensing circuitry configured to sense a physiological signal of a patient via one or more electrodes disposed on an implantable medical lead coupled to a medical device of the system; and processing circuitry configured to: determine that one or more features of the physiological signal are indicative of potential right ventricular (RV) lead dislodgement; determine a patient risk level of the patient based on one or more of: an underlying heart rate of the patient; or user input indicative of the patient risk level; and based on the determination that one or more features of the physiological signal are indicative of potential RV lead dislodgement and the patient risk level meeting a criterion, send an emergency alert to a user.

[0177] Example 2. The system of example 1, wherein the processing circuitry is further configured to: prompt the patient to confirm the emergency alert; and responsive to one of the patient confirming the emergency alert or the patient not responding to the emergency alert for a threshold period of time, send the emergency alert.

[0178] Example 3. The system of any of examples 1 or 2, wherein the physiological signal comprises a ventricular cardiac electrogram (VEGM) and an atrial cardiac electrogram (AEGM), and wherein the one or more features of the physiological signal comprises a correlation between the VEGM and the AEGM.Atty Ref. No.: A0012234W001

[0179] Example 4. The system of any of examples 1-3, wherein the physiological signal comprises a VEGM and an AEGM, and wherein to determine the potential RV lead dislodgement, the processing circuitry is configured to at least: determine a correlation between timings of atrial sensed events in the AEGM and timings of ventricular sensed events in the VEGM; and responsive to the correlation between the timings of the atrial sensed events and the ventricular sensed events meeting a similarity threshold, determine the one or more features of the physiological signal are indicative of the potential RV lead dislodgement.

[0180] Example 5. The system of any of examples 1-2, wherein the processing circuitry is further configured to: determine a correlation between timings of atrial sensed events in the AEGM and timings of ventricular sensed events in the VEGM; determine whether an atrial rate of the patient changed when the correlation met the similarity threshold, wherein in response to a determination that the atrial rate of the patient changed when the correlation met the similarity threshold, determine the correlation corresponds to a cardiac episode, and in response to a determination that the atrial rate of the patient did not change when the correlation met the similarity threshold, determine the correlation corresponds to the potential RV lead dislodgement.

[0181] Example 6. The system of any of examples 1-4, wherein the physiological signal comprises a first physiological signal, and wherein the processing circuitry is further configured to: responsive to the determination that one or more features of the first physiological signal are indicative of potential RV lead dislodgement, determine one or more features of a second physiological signal are indicative of potential RV lead dislodgement.

[0182] Example 7. The system of any of examples 1-5, wherein the physiological signal comprises: an impedance signal; a cardiac electrogram (EGM) signal; a blood pressure (BP) signal; or an accelerometer signal.

[0183] Example 8. The system of any of examples 1-6, wherein the one or more features of the physiological signal include one or more of: a change in impedance feature; a P-wave amplitude feature; an R-wave amplitude feature; an atrial activity in a VEGM feature; or a pacing capture threshold (PCT) feature.

[0184] Example 9. The system of example 7, wherein the medical device comprises a dual-chamber pacemaker, and wherein to determine the atrial activity in theAtly Ref. No.: A0012234W001VEGM feature, the processing circuitry is configured to: control therapy delivery circuitry of the pacemaker to deliver atrial pacing via one or more of the one or more electrodes of a right atrial (RA) lead of the medical device; and determine whether a VEGM signal corresponding to the atrial pacing is indicative of RV lead migration.

[0185] Example 10. The system of any of examples 1-8, wherein the patient risk level comprises a predetermined patient risk level.

[0186] Example 11. The system of any of examples 1-9, wherein the emergency alert includes a patient condition of the patient.

[0187] Example 12. The system of any of examples 1-10, wherein the system comprises a wearable device configured to sense an additional physiological signal indicative of the underlying heart rate of the patient.

[0188] Example 13. The system of any of examples 1-11, wherein when the risk level does not meet the criterion, the processing circuitry is configured to send a nonemergency alert to the user.

[0189] Example 14. The system of any of examples 1-12, wherein the user comprises one or more of: an emergency responder; the patient; a caregiver; or a clinician.

[0190] Example 15. The system of any of examples 1-13, wherein the processing circuitry comprises processing circuitry of one or more of: the medical device; or a computing device of the user.

[0191] Example 16. The system of any of examples 1-14, wherein the emergency alert comprises one or more of a visual, audio, or tactile alert.

[0192] Example 17. The system of any of examples 1-15, wherein the processing circuitry is configured to send the emergency alert to a computing device of the user.

[0193] Example 18. A method comprising: determining, by processing circuitry of a system comprising an implantable medical lead coupled to a medical device, that one or more features of a physiological signal are indicative of potential right ventricular (RV) lead dislodgement, wherein the medical device comprises sensing circuitry configured to sense the physiological signal of the patient via one or more electrodes disposed on the implantable medical lead; determining, by the processing circuitry, a patient risk level of the patient based on one or more of: an underlying heart rate of the patient; or user input indicative of the patient risk level; and sending, by the processing circuitry and based onAty Ref. No.: A0012234W001 the determination that one or more features of the physiological signal are indicative of potential RV lead dislodgement and the patient risk level meeting a criterion, an emergency alert to a user.

[0194] Example 19. The method of example 18, further comprising: prompting, by the processing circuitry, the patient to confirm the emergency alert; and sending, by the processing circuitry and responsive to one of the patient confirming the emergency alert or the patient not responding to the emergency alert for a threshold period of time, the emergency alert.

[0195] Example 20. The method of any of examples 18 or 19, wherein the physiological signal comprises a ventricular cardiac electrogram (VEGM) and an atrial cardiac electrogram (AEGM), and wherein the one or more features of the physiological signal comprises a correlation between the VEGM and the AEGM.

[0196] Example 21. The method of any of examples 18-20, wherein the physiological signal comprises a VEGM and an AEGM, and wherein determining the potential RV lead dislodgement comprises: determining, by the processing circuitry, a correlation between timings of atrial sensed events in the AEGM and timings of ventricular sensed events in the VEGM; and determining, by the processing circuitry and responsive to the correlation between the timings of the atrial sensed events and the ventricular sensed events meeting a similarity threshold, the one or more features of the physiological signal are indicative of the potential RV lead dislodgement.

[0197] Example 22. The method of any of examples 18-19, further comprising: determining, by the processing circuitry, a correlation between timings of atrial sensed events in the AEGM and timings of ventricular sensed events in the VEGM; determining, by the processing circuitry, whether an atrial rate of the patient changed when the correlation met the similarity threshold, wherein in response to a determination that the atrial rate of the patient changed when the correlation met the similarity threshold, determining, by the processing circuitry, that the correlation corresponds to a cardiac episode, and in response to a determination that the atrial rate of the patient did not change when the correlation met the similarity threshold, determining, by the processing circuitry, that the correlation corresponds to the potential RV lead dislodgement.

[0198] Example 23. The method of any of examples 18-22, wherein the physiological signal comprises a first physiological signal, the method further comprising:Aty Ref. No.: A0012234W001 determining, by the processing circuitry and responsive to the determination that one or more features of the first physiological signal are indicative of potential RV lead dislodgement, one or more features of a second physiological signal are indicative of potential RV lead dislodgement.

[0199] Example 24. The method of any of examples 19-23, wherein the physiological signal comprises one or more of: an impedance signal; a cardiac electrogram (EGM) signal; a blood pressure (BP) signal; or an accelerometer signal.

[0200] Example 25. The method of any of examples 18-24, wherein the one or more features of the physiological signal include one or more of: a change in impedance feature; a P-wave amplitude feature; an R-wave amplitude feature; an atrial activity in a VEGM feature; or a pacing capture threshold (PCT) feature.

[0201] Example 26. The method of example 25, wherein the medical device comprises a dual-chamber pacemaker, and wherein determining the atrial activity in the VEGM feature comprises controlling, by the processing circuitry, therapy delivery circuitry of the pacemaker to deliver atrial pacing via one or more of the one or more electrodes of a right atrial (RA) lead of the medical device; and determining, by the processing circuitry, whether a VEGM signal corresponding to the atrial pacing is indicative of RV lead migration.

[0202] Example 27. The method of any of examples 18-26, wherein the patient risk level comprises a predetermined patient risk level.

[0203] Example 28. The method of any of examples 18-27, wherein the emergency alert includes a patient condition of the patient.

[0204] Example 29. The method of any of examples 18-28, wherein the system comprises a wearable device configured to sense an additional physiological signal indicative of the underlying heart rate of the patient.

[0205] Example 30. The method of any of examples 18-29, further comprising: sending, by the processing circuitry, a non-emergency alert to the user when the risk level does not meet the criterion.

[0206] Example 31. The method of any of examples 18-30, wherein the user comprises one or more of: an emergency responder; the patient; a caregiver; or a clinician.Atly Ref. No.: A0012234W001

[0207] Example 32. The method of any of examples 18-31, wherein the processing circuitry comprises processing circuitry of one or more of: the medical device; or a computing device of the user.

[0208] Example 33. The method of any of examples 18-32, wherein the emergency alert comprises one or more of a visual, audio, or tactile alert.

[0209] Example 34. The method of any of examples 18-33, wherein the processing circuitry is configured to send the emergency alert to a computing device of the user.

[0210] Example 35. A non-transitory computer-readable medium storing instructions that when executed cause processing circuitry of a system to: determine that one or more features of a physiological signal are indicative of potential right ventricular (RV) lead dislodgement, wherein sensing circuitry of the system is configured to sense the physiological signal via one or more electrodes disposed on an implantable medical lead coupled to a medical device of the system; determine a patient risk level of the patient based on one or more of: an underlying heart rate of the patient; or user input indicative of the patient risk level; and based on the determination that one or more features of the physiological signal are indicative of potential RV lead dislodgement and the patient risk level meeting a criterion, send an emergency alert to a user

[0211] Example 36. A system comprising: sensing circuitry configured to sense a physiological signal of a patient via one or more electrodes disposed on an implantable medical lead coupled to a medical device of the system; and processing circuitry configured to: determine that one or more features of the physiological signal are indicative of potential right ventricular (RV) lead dislodgement; compare an underlying heart rate of the patient to a threshold; and responsive to the underlying heart rate meeting the threshold and the determination that one or more features of the physiological signal are indicative of potential RV lead dislodgement, send an emergency alert to a user.

[0212] Example 37. The system of example 36, wherein the processing circuitry is further configured to: prompt the patient to confirm the emergency alert; and responsive to one of the patient confirming the emergency alert or the patient not responding to the emergency alert for a threshold period of time, send the emergency alert.

[0213] Example 38. The system of example 36, wherein the threshold comprises a first threshold, and wherein the processing circuitry is further configured to: responsiveAty Ref. No.: A0012234W001 to the underlying heart rate meeting the first threshold, compare the underlying heart rate to a second threshold, wherein responsive to the comparison of the underlying heart rate to the second threshold satisfying a first one or more criteria, the processing circuitry is configured to: generate for output a prompt to the patient to confirm the emergency alert; and responsive to one of the patient confirming the emergency alert or the patient not responding to the prompt for a threshold period of time, control communication circuitry to send the emergency alert, and wherein responsive to the comparison of the underlying heart rate to the second threshold satisfying a second one or more criteria different from the first one or more criteria, the processing circuitry is configured to: control processing circuitry to send an emergency alert without outputting the prompt to the user to confirm the emergency alert.

[0214] Example 39. The system of any of examples 36-38, wherein the physiological signal comprises a first physiological signal, and wherein the processing circuitry is further configured to: responsive to the determination that one or more features of the first physiological signal are indicative of potential RV lead dislodgement, determine one or more features of a second physiological signal are indicative of potential RV lead dislodgement.

[0215] Example 40. The system of any of examples 36-39, wherein the physiological signal comprises: an impedance signal; a cardiac electrogram (EGM) signal; a blood pressure (BP) signal; or an accelerometer signal.

[0216] Example 41. The system of any of examples 36-40, wherein the one or more features of the physiological signal include one or more of: a change in impedance feature; a pacing capture threshold (PCT) feature; a P-wave amplitude feature; an R-wave amplitude feature; or an atrial activity in a ventricular cardiac EGM (VEGM) feature.

[0217] Example 42. The system of example 41, wherein the medical device comprises a dual-chamber pacemaker, and wherein to determine the atrial activity in the VEGM feature, the processing circuitry is configured to: control therapy delivery circuitry of the pacemaker to deliver atrial pacing via one or more of the one or more electrodes of a right atrial (RA) lead of the medical device; and determine whether a VEGM signal corresponding to the atrial pacing is indicative of RV lead migration.

[0218] Example 43. The system of any of examples 36-42, wherein the emergency alert includes a priority level based on the underlying heart rate of the patient.Atly Ref. No.: A0012234W001

[0219] Example 44. The system of any of examples 38-43, wherein the first threshold is 30 beats per minute (bpm) and the second threshold is 15 bpm.

[0220] Example 45. The system of any of examples 36-44, wherein the system comprises a wearable device configured to sense an additional physiological signal indicative of the underlying heart rate of the patient.

[0221] Example 46. The system of any of examples 36-45, wherein when the underlying heart rate does not meet the threshold, the processing circuitry is configured to send a non-emergency alert to the user.

[0222] Example 47. The system of any of examples 36-46, wherein the user comprises one or more of: an emergency responder; the patient; a caregiver; or a clinician.

[0223] Example 48. The system of any of examples 36-47, wherein the processing circuitry comprises processing circuitry of one or more of: the medical device; or a computing device of the user.

[0224] Example 49. The system of any of examples 36-48, wherein the emergency alert comprises one or more of a visual, audio, or tactile alert.

[0225] Example 50. The system of any of examples 36-49, wherein the emergency alert comprises: an indication of the underlying heart rate of the patient; and an indication of the physiological signal indicative of the potential RV lead dislodgement.

[0226] Example 51. The system of any of examples 36-50, wherein the processing circuitry is configured to send the emergency alert to a computing device of the user.

[0227] Example 52. A method comprising: determining, by processing circuitry of a system comprising an implantable medical lead coupled to a medical device, that one or more features of a physiological signal are indicative of potential right ventricular (RV) lead dislodgement, wherein the medical device comprises sensing circuitry configured to sense the physiological signal of the patient via one or more electrodes disposed on the implantable medical lead; comparing, by the processing circuitry, an underlying heart rate of the patient to a threshold; and sending, by the processing circuitry and responsive to the underlying heart rate meeting the threshold and the determination that the one or more features of the physiological signal are indicative of potential RV lead dislodgement, an emergency alert to a user.Atty Ref. No.: A0012234W001

[0228] Example 53. The method of example 52, further comprising: prompting, by the processing circuitry, the patient to confirm the emergency alert; and sending, by the processing circuitry and responsive to one of the patient confirming the emergency alert or the patient not responding to the emergency alert for a threshold period of time, the emergency alert.

[0229] Example 54. The method of example 52, wherein the threshold comprises a first threshold, the method further comprising: comparing, by the processing circuitry and responsive to the underlying heart rate meeting the first threshold, the underlying heart rate to a second threshold, wherein responsive to the comparison of the underlying heart rate to the second threshold satisfying a first one or more criteria, the processing circuitry is configured to: generate for output a prompt to the patient to confirm the emergency alert; and responsive to one of the patient confirming the emergency alert or the patient not responding to the prompt for a threshold period of time, control communication circuitry to send the emergency alert, and wherein responsive to the comparison of the underlying heart rate to the second threshold satisfying a second one or more criteria different from the first one or more criteria, the processing circuitry is configured to: control processing circuitry to send an emergency alert without outputting the prompt to the user to confirm the emergency alert.

[0230] Example 55. The method of any of examples 52-54, wherein the physiological signal comprises a first physiological signal, the method further comprising: determining, by the processing circuitry and responsive to the determination that one or more features of the first physiological signal are indicative of potential RV lead dislodgement, one or more features of a second physiological signal are indicative of potential RV lead dislodgement.

[0231] Example 56. The method of any of examples 52-55, wherein the physiological signal comprises: an impedance signal; a cardiac electrogram (EGM) signal; a blood pressure (BP) signal; or an accelerometer signal.

[0232] Example 57. The method of any of examples 52-56, wherein the one or more features of the physiological signal include one or more of: a change in impedance feature; a pacing capture threshold (PCT) feature; an R-wave amplitude feature; a P-wave amplitude feature; or an atrial activity in a ventricular cardiac EGM (VEGM) feature.Atty Ref. No.: A0012234W001

[0233] Example 58. The method of example 57, wherein the medical device comprises a dual-chamber pacemaker, and wherein determining the atrial activity in the VEGM feature comprises: controlling, by the processing circuitry, therapy delivery circuitry of the pacemaker to deliver atrial pacing via one or more of the one or more electrodes of a right atrial (RA) lead of the medical device; and determining, by the processing circuitry, whether a VEGM signal corresponding to the atrial pacing is indicative of RV lead migration.

[0234] Example 59. The method of any of examples 52-58, wherein the emergency alert includes a priority level based on the underlying heart rate of the patient.

[0235] Example 60. The method of any of examples 55-59, wherein the first threshold is 30 beats per minute (bpm) and the second threshold is 15 bpm.

[0236] Example 61. The method of any of examples 52-60, wherein the system comprises a wearable device configured to sense an additional physiological signal indicative of the underlying heart rate of the patient.

[0237] Example 62. The method of any of examples 52-61, wherein when the underlying heart rate does not meet the threshold, the processing circuitry is configured to send a non-emergency alert to the user.

[0238] Example 63. The method of any of examples 52-62, wherein the user comprises one or more of: an emergency responder; the patient; a caregiver; or a clinician.

[0239] Example 64. The method of any of examples 52-63, wherein the processing circuitry comprises processing circuitry of one or more of: the medical device; or a computing device of the user.

[0240] Example 65. The method of any of examples 52-64, wherein the emergency alert comprises one or more of a visual, audio, or tactile alert.

[0241] Example 66. The method of any of examples 52-65, wherein the emergency alert comprises: an indication of the underlying heart rate of the patient; and an indication of the physiological signal indicative of the potential RV lead dislodgement.

[0242] Example 67. The method of any of examples 52-66, wherein sending the emergency alert comprises sending the emergency alert to a computing device of the user.

[0243] Example 68. A non-transitory computer-readable medium storing instructions that when executed cause processing circuitry to: determine that one or more features of a physiological signal of a patient sensed by sensing circuitry of a medicalAtty Ref. No.: A0012234W001 device of a system via one or more electrodes disposed on an implantable medical lead coupled to the medical device are indicative of potential right ventricular (RV) lead dislodgement; responsive to the determination one or more features of the physiological signal are indicative of potential RV lead dislodgement, compare an underlying heart rate of the patient to a threshold; and responsive to the underlying heart rate meeting the threshold, send an emergency alert to a user.

[0244] Various examples have been described. These and other examples are within the scope of the following claims.

Claims

Atly Ref. No.: A0012234W001WHAT IS CLAIMED IS:

1. A system comprising: sensing circuitry configured to sense a physiological signal of a patient via one or more electrodes disposed on an implantable medical lead coupled to a medical device of the system; and processing circuitry configured to: determine that one or more features of the physiological signal are indicative of potential right ventricular (RV) lead dislodgement; determine a patient risk level of the patient based on one or more of: an underlying heart rate of the patient; or user input indicative of the patient risk level; and based on the determination that one or more features of the physiological signal are indicative of potential RV lead dislodgement and the patient risk level meeting a criterion, send an emergency alert to a user.

2. The system of claim 1, wherein the processing circuitry is further configured to: prompt the patient to confirm the emergency alert; and responsive to one of the patient confirming the emergency alert or the patient not responding to the emergency alert for a threshold period of time, send the emergency alert.

3. The system of any of claims 1 or 2, wherein the physiological signal comprises a ventricular cardiac electrogram (VEGM) and an atrial cardiac electrogram (AEGM), and wherein the one or more features of the physiological signal comprises a correlation between the VEGM and the AEGM.

4. The system of any of claims 1 or 2, wherein the physiological signal comprises a VEGM and an AEGM, and wherein to determine the potential RV lead dislodgement, the processing circuitry is configured to at least: determine a correlation between timings of atrial sensed events in the AEGM and timings of ventricular sensed events in the VEGM; andAtty Ref. No.: A0012234W001 responsive to the correlation between the timings of the atrial sensed events and the ventricular sensed events meeting a similarity threshold, determine the one or more features of the physiological signal are indicative of the potential RV lead dislodgement.

5. The system of any of claims 1 or 2, wherein the processing circuitry is further configured to: determine a correlation between timings of atrial sensed events in the AEGM and timings of ventricular sensed events in the VEGM; determine whether an atrial rate of the patient changed when the correlation met the similarity threshold, wherein in response to a determination that the atrial rate of the patient changed when the correlation met the similarity threshold, determine the correlation corresponds to a cardiac episode, and in response to a determination that the atrial rate of the patient did not change when the correlation met the similarity threshold, determine the correlation corresponds to the potential RV lead dislodgement.

6. The system of any of claims 1-5, wherein the physiological signal comprises a first physiological signal, and wherein the processing circuitry is further configured to: responsive to the determination that one or more features of the first physiological signal are indicative of potential RV lead dislodgement, determine one or more features of a second physiological signal are indicative of potential RV lead dislodgement.

7. The system of any of claims 1-6, wherein the physiological signal comprises: an impedance signal; a cardiac electrogram (EGM) signal; a blood pressure (BP) signal; or an accelerometer signal.

8. The system of any of claims 1-7, wherein the one or more features of the physiological signal include one or more of: a change in impedance feature;Atly Ref. No.: A0012234W001 a P-wave amplitude feature; an R-wave amplitude feature; an atrial activity in a VEGM feature; or a pacing capture threshold (PCT) feature.

9. The system of claim 8, wherein the medical device comprises a dual-chamber pacemaker, and wherein to determine the atrial activity in the VEGM feature, the processing circuitry is configured to: control therapy delivery circuitry of the pacemaker to deliver atrial pacing via one or more of the one or more electrodes of a right atrial (RA) lead of the medical device; and determine whether a VEGM signal corresponding to the atrial pacing is indicative of RV lead migration.

10. The system of any of claims 1-9, wherein the patient risk level comprises a predetermined patient risk level.

11. The system of any of claims 1-10, wherein the emergency alert includes a patient condition of the patient.

12. The system of any of claims 1-11, wherein the system comprises a wearable device configured to sense an additional physiological signal indicative of the underlying heart rate of the patient.

13. The system of any of claims 1-12, wherein the processing circuitry comprises processing circuitry of one or more of the medical device; or a computing device of the user.

14. The system of any of claims 1-13, wherein the processing circuitry is configured to send the emergency alert to a computing device of the user.Aty Ref. No.: A0012234W00115. A non-transitory computer-readable medium storing instructions that when executed cause processing circuitry of a system to: determine that one or more features of a physiological signal are indicative of potential right ventricular (RV) lead dislodgement, wherein sensing circuitry of the system is configured to sense the physiological signal via one or more electrodes disposed on an implantable medical lead coupled to a medical device of the system; determine a patient risk level of the patient based on one or more of: an underlying heart rate of the patient; or user input indicative of the patient risk level; and based on the determination that one or more features of the physiological signal are indicative of potential RV lead dislodgement and the patient risk level meeting a criterion, send an emergency alert to a user.

Images