Short term variability of cardiac electrical activity for triggering external actions to reduce arrhythmia

Abstract

Possible onset of ventricular arrhythmia is predicted and steps are taken to prevent arrhythmia, which can provide improved patient outcome and improved patient acceptance. Some examples of steps include triggering another device to deliver therapy, such as triggering a pacemaker to output electrical stimulation therapy, triggering a fluid delivery device to deliver a substance to reduce the likelihood of arrhythmia, or sending a warning to cause a patient to change posture or activity. The detection techniques of the present disclosure include various detection algorithms. Some detection schemes may consume more resources than other detection schemes, and thus may consume more power and reduce battery life. A system implementing the techniques of the present disclosure may employ detection techniques that consume relatively low energy sometimes and that employ detection techniques that use relatively high energy sometimes.

Description

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 481,843, filed January 27, 2023, which is incorporated herein by reference in its entirety. Technical Field

[0002] The present disclosure relates to medical devices, and in particular to implantable cardiac rhythm medical devices. Background Art

[0003] A patient's cardiac rhythm management may include detecting and helping the patient recover from dangerous arrhythmias, such as bradycardia, pauses, ventricular tachycardia (VT), or ventricular fibrillation (VF). The patient may wear a medical device, such as an implanted, partially implanted, or wearable medical device, that can detect and monitor the patient's cardiac activity and monitor other patient conditions. In some examples, such a medical device may provide therapy to help treat the detected arrhythmia. Summary of the Invention

[0004] In general, the present disclosure describes devices, systems, and techniques for predicting potential ventricular tachyarrhythmias (such as VT or VF) and taking action to minimize or prevent the arrhythmia. Some patients at risk for potentially dangerous arrhythmias may resist receiving a cardiac defibrillator, such as a wearable defibrillator or an implantable cardiac defibrillator (ICD), due to a fear of receiving electrical therapy. In some examples, anti-tachyarrhythmia therapy (e.g., an electric shock) may be painful or at least frightening. The technology of the present disclosure can predict the possible onset of a ventricular arrhythmia and take steps to prevent the arrhythmia, which can provide improved patient outcomes and improved patient acceptance.

[0005] Some examples of possible actions may include triggering another device to deliver therapy, such as triggering a pacemaker to output electrical stimulation therapy, triggering a fluid delivery device to deliver a drug or other substance to reduce the likelihood of an arrhythmia, or sending a warning to cause the patient to change posture or activity. In some examples, the arrhythmia prediction techniques of the present disclosure may include multiple techniques, one or more of which may consume more resources than one or more other techniques and, therefore, may consume more power and reduce battery life. A system implementing the techniques of the present disclosure may employ an arrhythmia prediction technique that consumes relatively low energy at certain times and employ an arrhythmia prediction detection technique that uses relatively high energy at other times.

[0006] In one example, the present disclosure describes a system comprising: sensing circuitry configured to sense cardiac activity of a patient; detecting a precursor to a ventricular tachyarrhythmia based on the sensed cardiac activity; and delivering non-shock therapy to suppress the onset of the ventricular tachyarrhythmia in response to detecting the precursor to the ventricular tachyarrhythmia.

[0007] In other examples, the present disclosure describes a method comprising: sensing, by sensing circuitry of a medical system, cardiac activity of a patient; receiving, by processing circuitry of the medical system, an indication of the cardiac activity of the patient; detecting, by the processing circuitry, based on the sensed cardiac activity, that the sensed cardiac activity includes a precursor to a ventricular tachyarrhythmia; and in response to detecting the precursor to the ventricular tachyarrhythmia, causing, by the processing circuitry, delivery of the non-shock therapy to inhibit the onset of the ventricular tachyarrhythmia.

[0008] In another example, the present disclosure describes a non-transitory computer-readable storage medium comprising instructions that, when executed, cause a processing circuit of a computing device to: receive an indication of cardiac activity of a patient from a sensing circuit of a medical system, wherein: the sensing circuit is configured to sense cardiac activity of the patient and the computing device is a component of the medical system; detect a precursor to a ventricular tachyarrhythmia based on the sensed cardiac activity; and in response to detecting the precursor to the ventricular tachyarrhythmia, deliver a non-shock therapy to suppress the onset of the ventricular tachyarrhythmia.

[0009] In another example, the present disclosure describes a method comprising: receiving, by a processing circuit, an indication of sensed cardiac activity from a sensing circuit of a medical system configured to sense cardiac activity of a patient; detecting, by the processing circuit of the medical system, a first precursor of a ventricular tachyarrhythmia based on the sensed cardiac activity, and applying, by the processing circuit, a precursor detection algorithm to the sensed cardiac activity in response to detecting the first precursor; and confirming, by the processing circuit, an indication of an episode of ventricular tachycardia based on the first precursor and the applied precursor detection algorithm; and causing, by the processing circuit, the delivery of non-shock therapy to suppress the episode of ventricular tachyarrhythmia in response to detecting the indication of the episode of ventricular tachyarrhythmia.

[0010] In another example, the present disclosure describes a medical system comprising: a sensing circuit configured to sense cardiac activity of a patient; a processing circuit configured to receive an indication of the sensed cardiac activity from the sensing circuit; detecting a first precursor to a ventricular tachyarrhythmia based on the sensed cardiac activity; applying a precursor detection algorithm to the sensed cardiac activity in response to detecting the first precursor; and confirming, by the processing circuit, an indication of an episode of ventricular tachycardia based on the first precursor and the applied precursor detection algorithm; and causing delivery of non-shock therapy to suppress the episode of ventricular tachyarrhythmia in response to detecting the indication of the episode of ventricular tachyarrhythmia.

[0011] In another example, the present disclosure describes a non-transitory computer-readable storage medium comprising instructions that, when executed, cause processing circuitry of a computing device to: receive an indication of cardiac activity of a patient from sensing circuitry of a medical system, wherein: the sensing circuitry is configured to sense cardiac activity of the patient and the computing device is a component of the medical system; detect a first precursor to a ventricular tachyarrhythmia based on the sensed cardiac activity; in response to detecting the first precursor, apply a precursor detection algorithm to the sensed cardiac activity; and based on the first precursor and the applied precursor detection algorithm, confirm an indication of an onset of ventricular tachycardia; in response to detecting the indication of an onset of a ventricular tachyarrhythmia, cause delivery of non-shock therapy to suppress the onset of the ventricular tachyarrhythmia.

[0012] The details of one or more examples of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the disclosure will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 illustrative embodiments illustrate an example system configured to predict cardiac arrhythmias in accordance with one or more techniques of this disclosure.

[0014] Figure 2 is a conceptual diagram illustrating an example system for predicting cardiac arrhythmias, including an implantable defibrillator, in accordance with one or more techniques of this disclosure.

[0015] Figure 3 is a conceptual diagram illustrating an example system for predicting cardiac arrhythmias, including a wearable medical device, in accordance with one or more techniques of this disclosure.

[0016] Figure 4 is a conceptual diagram illustrating neural tissue of a patient, in accordance with one or more techniques of this disclosure.

[0017] Figure 5is a block diagram illustrating an example medical device in accordance with one or more techniques of this disclosure.

[0018] Figure 6 One example of an electrogram signal that may be sensed by one or more systems of the present disclosure is shown.

[0019] Figure 7 is a flow diagram illustrating example operation of a system in accordance with one or more techniques of this disclosure. DETAILED DESCRIPTION

[0020] The present disclosure describes devices, systems, and techniques for predicting potential ventricular arrhythmias and taking action to minimize or prevent them. Predicting and preventing irregular and potentially dangerous arrhythmias can improve patient outcomes by reducing the likelihood that a patient will develop a tachyarrhythmia, such as ventricular tachycardia and ventricular fibrillation (VT / VF). The technology of the present disclosure may include devices that sense and analyze biosignals to determine whether there are possible precursors to arrhythmias.

[0021] Example techniques may include analyzing short-term variability (STV). The presence of STV in a patient can be a precursor to predicting the onset of VT / VF. In one example, the onset of VT / VF can be predicted within a range of one to fifteen minutes before the arrhythmia occurs. In some examples, the system may include at least two separate medical devices that can sense heart rhythm, for example, any cardiovascular implantable electronic device (CIED), such as a pacemaker, including a leadless pacemaker, an implantable cardiac monitor (ICM), an implantable cardioverter-defibrillator (ICD), or other implantable medical device (IMD), and / or wearable medical devices and the like. In some examples, the medical devices can independently sense and analyze biosignals and then communicate with each other to confirm the presence of precursors. In other examples, detection of an arrhythmia precursor by one device can trigger a second device to begin applying a precursor detection algorithm, such as an STV algorithm. When the system determines that a ventricular arrhythmia may be about to occur, one or more of the devices can deliver anti-tachyarrhythmia therapy.

[0022] In other examples, detection of one or more precursors to an arrhythmia by one or more devices (such as the aforementioned CIEDs, hemodynamic monitors, pulse wave velocity monitors, and the like) can trigger neurocardiology therapy to restore STV parameters and prevent an impending tachyarrhythmia. For example, when an STV parameter reaches a given threshold, a neurostimulator (such as an implantable neurostimulator (INS)) can initiate electrical stimulation therapy to the patient's neural tissue, for example, to reduce STV and prevent a life-threatening arrhythmia. Some examples may include vagus nerve stimulation, left stellate ganglion block, or other neural tissue stimulation.

[0023] In other examples, one or more devices may deliver refractory stimulation. Refractory stimulation may be different from applying stimulation during the excitable period (non-refractory period). For example, unlike non-refractory stimulation delivered to cardiac tissue (which may be intended to capture cardiac tissue), electrical stimulation delivered during the refractory period may be non-capturing stimulation intended to modify the refractory period with the goal of preventing the onset of VT / VF. In the present disclosure, "capturing" cardiac tissue means activating the myocardium. For example, a capture threshold for electrical stimulation may refer to a measurement of a minimum voltage, or a minimum current capture threshold is the minimum current setting that produces depolarization of cardiac tissue (e.g., the cardiac chamber to which the electrical stimulation is applied).

[0024] In other examples, detection of one or more precursors to an arrhythmia can trigger an electronic message to an external computing device (such as a smartphone) to notify the patient and / or caregiver that the patient should take some action. Some example notifications may include instructions to take antiarrhythmic medication, stop caffeine intake, change posture or activity, or other similar actions.

[0025] In other examples, a first arrhythmia prediction (e.g., precursor detection) algorithm may trigger a second precursor detection algorithm, where the second precursor detection algorithm consumes more resources than the first precursor detection algorithm. Some examples of resources may include battery power consumption, processor time, memory storage, and similar resources of the medical device. Any of the above actions may be considered anti-tachyarrhythmia therapy.

[0026] Figure 1 is a conceptual diagram illustrating an example medical device system 10 configured to predict cardiac arrhythmias in accordance with one or more techniques of the present disclosure. The systems, devices, and methods described in the present disclosure may include an example configuration of medical device system 10 having one or more implantable medical devices, such as IMD 12 and IMD 14, implanted or partially implanted within a patient. For purposes of this description, an understanding of cardiovascular anatomy and function is assumed, and details are omitted except to the extent necessary or desirable to explain the context of the present disclosure.

[0027] System 10 includes an external computing device 22, one or more servers 24, and IMDs 14 and 12 implanted at or near the heart 17 of patient 26. IMDs 14 and 12 can communicate with external computing device 22, server 24, and Figure 1 Wireless communication with at least one of the other devices not shown in the figure.

[0028] In some examples, IMD 14 or a similar medical device may be implanted outside the chest of patient 26 (e.g., subcutaneously in the Figure 1). In other examples, IMD 14 may be positioned near the sternum near or just below the level of patient 26's heart, e.g., at least partially within the outline of the heart. In other examples, IMD 14 may be proximate to, attached to, or implanted on the epicardium of heart 17. In other examples, IMD 14 may be positioned at other locations in patient 26, including for monitoring and stimulation of the tibial nerve, subcutaneous nerves, sacral nerves, spinal cord, vagus nerve, deep brain stimulation, at or near one or more organs or other locations. In some examples, IMD 14 may be implemented as an insertable cardiac monitor (ICM) for long-term (chronic) monitoring of cardiac activity in patient 26.

[0029] IMD 14 includes a plurality of electrodes and may be configured to sense an electrocardiogram (EGM) and other bioelectrical signals via the plurality of electrodes. In some examples, the electrodes may be integrated with the housing of IMD 14. In various examples, IMD 14 may represent a cardiac monitor, a defibrillator, a cardiac resynchronization pacemaker or defibrillator, a pacemaker, an implantable pressure sensor, a neurostimulator, a glucose monitor, a drug pump, a pulse wave velocity measurement device, or any other implantable or external medical device.

[0030] In some examples, IMD 12 may be described as a pacemaker device 12. Pacemaker device 12 may be, for example, an implantable leadless pacemaker device configured for complete implantation in one of the chambers of heart 17 and providing electrical signals to heart 17 via electrodes carried on a housing of pacemaker device 12 (i.e., IMD 12). IMD 12 may be configured to be implanted proximal to the heart of patient 26, for example, to monitor the electrical activity of the heart and / or provide electrical therapy to the heart. In some examples, IMD 251 may be implemented as an atrioventricular (VfA) cardiac device and may be implanted in the right atrium (RA), with electrodes extending from the right atrium into the left ventricular (LV) myocardium.

[0031] In some examples, IMD 12 may be attached as an intracardiac pacing device within a chamber of heart 17. In other examples consistent with aspects of the present disclosure, IMD 12 may be attached to an external surface of heart 17 such that IMD 12 is positioned outside of heart 17 but can pace a desired chamber. In one example, IMD 12 is attached to an external surface of heart 17, and one or more components of IMD 12 may be in contact with the epicardium of heart 17. Figure 1In the example of FIG, an IMD 12 is schematically shown attached to a ventricular wall of heart 17 via one or more fixation elements (e.g., tines, helices, etc.) that penetrate tissue. These fixation elements can secure IMD 12 to the cardiac tissue and maintain electrodes (e.g., cathode or anode) in contact with the cardiac tissue. IMD 12 can be implanted at or near the apex of the heart. In other examples, the pacing device can be implanted at other ventricular locations, e.g., on the free wall or septum, at an atrial location, anywhere on or in heart 17, or at other locations within patient 26, as described above for IMD 14. For example, although Figure 1 The examples depict IMD 12 and IMD 14 as leadless IMDs, but in other examples, the techniques of this disclosure may be equally applicable to transvenous IMDs. In other words, IMD 14 or Figure 1 A third IMD, not shown, may be implanted in a pocket in the pectoral region of patient 26, with leads extending from the IMD to one or more locations in or on heart 17. As another example, IMD 12 may be implanted or coupled to leads implanted in the anterior mediastinum or another extracardiac location.

[0032] IMD 12 may include a housing that is hermetically or nearly hermetically sealed to help prevent fluids from entering the housing. IMD 12 may include electronic components, such as sensing circuitry for sensing cardiac electrical activity via electrodes and therapy generation circuitry for delivering electrical stimulation therapy via the electrodes. The electronic components may include any discrete and / or integrated electronic circuit components that implement analog and / or digital circuitry capable of producing the functions attributed to pacing device 12 as described herein. In some examples, IMD 12 may also include components for sensing other physiological parameters, such as acceleration, pressure, sound, and / or impedance.

[0033] Like IMD 14, IMD 12 may include memory that includes instructions that, when executed by processing circuitry within the housing of IMD 12, enable components of IMD 12 to perform the various functions attributed to IMD 12. In some examples, the housing may also house communication circuitry that enables IMD 12 to communicate with other electronic devices, such as external computing device 22, which may be a medical device programmer, patient monitor, or other external device. In some examples, IMD 12 may also include a power source, such as a battery.

[0034] In some examples, external computing device 22 may be a computing device having a display viewable by a user and an interface (i.e., a user input mechanism) for providing input to external computing device 22. In some examples, external computing device 22 may be a laptop computer, a tablet computer, a workstation, one or more servers, a cellular phone, a personal digital assistant, a patient monitor, or another computing device that can run an application that enables the computing device to interact with IMD 12 and IMD 14. External computing device 22 is configured to communicate with IMD 12 and IMD 14, and optionally with other devices (e.g., a computer) via wireless communication. Figure 1 For example, the external computing device 22 may communicate with one or more servers 24 via near field communication technology (e.g., inductive coupling, NFC, or other communication technology that can operate at a range of less than 10 cm to 20 cm), far field communication technology (e.g., according to 802.11 or RF telemetry or other communication technologies that can operate at a range greater than near-field communication technology), or wired communication (e.g., Ethernet).

[0035] External computing device 22 may be used to retrieve data collected by IMD 12 and IMD 14 and to configure operating parameters of IMD 12 and IMD 14. To simplify the explanation, the remaining description may refer only to IMD 14, but the same description applies to IMD 12 unless otherwise noted.

[0036] The retrieved data may include values ​​of physiological parameters measured by IMD 14, indications of an arrhythmia or other disease episode detected by IMD 14, and physiological signals recorded by IMD 14. For example, external computing device 22 may retrieve a cardiac EGM segment recorded by IMD 14, e.g., because IMD 14 determined that an arrhythmia or other disease episode occurred during the segment, or in response to a request from patient 26 or another user to record the segment. In some examples, one or more remote computing devices may interact with IMD 14 in a manner similar to external computing device 22, e.g., to program IMD 14 and / or retrieve data from IMD 14 via a network.

[0037] In various examples, IMD 14 may include one or more additional sensor circuits configured to sense specific physiological or neural parameters associated with patient 26. For example, IMD 14 may include a sensor operable to sense a temperature at the location of IMD 14 or at the location of the patient where a temperature sensor coupled to IMD 14 by a lead may be located. Figure 1In one embodiment, IMD 14 may include a sensor configured to sense the temperature of patient 26 (not shown). In another example, IMD 14 may include a sensor configured to sense motion or position, and, for example, an accelerometer, to sense steps taken by patient 26 and / or changes in position or posture of patient 26. In various examples, IMD 14 may include a sensor configured to detect the breathing of patient 26. In various examples, IMD 14 may include a sensor configured to detect the heartbeat of patient 26. In various examples, IMD 14 may include a sensor configured to measure systemic blood pressure or other biometrics of patient 26.

[0038] In some examples, system 10 may include one or more other sensors (e.g., implanted in patient 26, i.e., implanted at least below the level of the patient's skin) Figure 1 (not shown). In some examples, one or more of the sensors of IMD 14 may be positioned external to patient 26, e.g., as part of a cuff or as a wearable device, such as a device embedded in clothing worn by patient 26. In various examples, IMD 14 may be configured to sense one or more physiological parameters associated with patient 26 and send data corresponding to the sensed one or more physiological parameters to external computing device 22.

[0039] In various examples, data transmission from IMD 14 to external computing device 22 can be performed via wireless transmission, e.g., using any of the formats described above for wireless communication formats. In various examples, IMD 14 can wirelessly communicate with an external device (e.g., one or more instruments) in addition to or in addition to external computing device 22, such as a transceiver or access point that provides a wireless communication link between IMD 14 and a network. Figure 1 Examples of communication techniques used by any of the described devices may include radio frequency (RF) telemetry, which may be via RF link established by Wi-Fi or Medical Implant Communications Service (MICS).

[0040] In some examples, system 10 may include Figure 1 More or fewer components may be shown. For example, in some examples, system 10 may include multiple additional IMDs, such as implantable cardiac devices or other IMDs, implanted in patient 26. As another example, system 10 may include only a single IMD, such as only IMD 14.

[0041] For a single IMD example, IMD 14 may perform some analysis of cardiac activity of patient 26, where the analysis consumes first-level resources. The first analysis, which utilizes first-level resources, may trigger processing circuitry of IMD 14 to perform a second analysis of cardiac activity of patient 26, which utilizes second-level resources, where the second-level resources are greater than the first-level resources. For example, the second analysis may take longer than the first analysis and / or consume more energy from the battery of IMD 14 than the first analysis. Based on the first and second analyses, IMD 14 may deliver non-shock antiarrhythmic therapy to patient 26.

[0042] In some examples, IMD 14 may initiate the first analysis based on a triggering event. The triggering event may include any one or more of the expiration of a time period (e.g., hourly, daily, weekly, or some other periodic analysis), or the triggering event may be based on cardiac activity. For example, IMD 14 may detect one or more premature ventricular contractions (PVCs), a brief tachycardia interval, a time interval of one or more cardiac cycles that meets a threshold, or some other time interval that triggers cardiac activity.

[0043] In other examples, as described above, the first analysis from IMD 14 may trigger IMD 12 to perform a second analysis. Based on the first analysis and the second analysis indicating a precursor to a cardiac arrhythmia, either IMD 12 or IMD 14, or both, may deliver non-shock antiarrhythmic therapy to patient 26. The second analysis may be any combination of the same analysis repeated from a different device in a different location (e.g., where different electrodes receive cardiac signals through different pathways, the same analysis is repeated more frequently or for a longer duration by the same or different device), a different analysis of bioelectrical signals performed using the same or different device and / or processing circuitry, e.g., an STV analysis as described herein, or any similar technique that can confirm a precursor to a tachyarrhythmia.

[0044] For the remainder of this disclosure, general references to medical device systems may generally refer to any examples including medical device system 10, general references to IMD 14 may generally refer to any examples including IMD 14 and IMD 12, general references to sensor circuits may generally refer to any examples including sensor circuits of IMD 14 and IMD 12, and general references to external devices may generally refer to any examples of external computing device 22.

[0045] In one example of the operation of system 10, the combination of IMD 14 and IMD 12 can capture the dispersion of electrical signals in a wider area of ​​the heart than either IMD 12 or IMD 14 alone. In other words, system 10 can use both IMD 12 and IMD 14 to measure cardiac activity and analyze the combined results to trigger therapy or avoid triggering unnecessary therapy. For example, as described above, one or both of IMD 12 and IMD 14 can use a short-term variability algorithm to analyze the sensed cardiac rhythm. As described above, the presence of STV in a patient can be a precursor to predicting the onset of a tachyarrhythmia. In some examples, external computing device 22 and / or server 24 can also analyze the sensed cardiac rhythm. If any of the processing circuitry of any component of system 10 detects an STV or some other precursor to tachyarrhythmia in the cardiac signal that meets one or more criteria, the processing circuitry can trigger anti-tachyarrhythmia therapy. Examples of anti-tachyarrhythmia therapy may include overdrive pacing or other high-speed pacing, which, for example, is delivered by IMD 12, coupled to a pump ( Figure 1 (not shown) to automatically infuse a substance, trigger a neurostimulator to output a neurocardiology therapy to restore STV parameters and prevent an impending tachyarrhythmia, or some other shockable or non-shockable anti-tachyarrhythmia therapy as described above.

[0046] In the present disclosure, STV can be measured in many different ways. In some examples, STV can be measured in time (temporal dispersion), such as variability in various parts of the cardiac cycle, including QT variability, ST variability (which can also be referred to as variability in activation recovery interval (ARI)), PP interval variability, and other temporal measurements of the cardiac cycle. In other examples, STV can also describe variability in amplitude (e.g., changes in T wave maximum and type of T wave alternation) and morphology variability.

[0047] Figure 2 is a conceptual diagram illustrating an example system for predicting cardiac arrhythmias, including an implantable cardioverter-defibrillator (ICD), in accordance with one or more techniques of this disclosure. Figure 2 The example of FIG25 shows a front view of a patient 226 having an extracardiovascular ICD system implanted in the chest cavity and one or more other IMDs (e.g., IMD 251). In this disclosure, an extracardiovascular ICD may also be referred to as an extravascular implantable cardioverter-defibrillator (EV-ICD). Figure 1 The system 10 described above, the system 200 may include one or more external computing devices 221 configured to communicate with the EV-ICD 209 and the IMD 251, and with one or more servers ( Figure 2EV-ICD 209 and IMD 251 may also be configured to communicate directly with each other, as described above with respect to Figure 1 As stated.

[0048] The ICD system 210 includes an EV-ICD 209 connected to a medical electrical lead 212. The EV-ICD 209 may include a housing that forms an airtight seal protecting the components of the EV-ICD 209. The housing of the EV-ICD 209 may be formed from a conductive material, such as titanium or a titanium alloy, which may serve as a housing electrode (sometimes referred to as a can electrode). In other embodiments, the EV-ICD 209 may be formed with or include one or more electrodes located on the outermost portion of the housing. The EV-ICD 209 may also include a connector assembly (also referred to as a connector block or plug) that includes electrical feedthroughs that electrically connect the conductors of the lead 212 to the electronic components included within the housing of the EV-ICD 209. The housing may enclose one or more processors, memory, a transmitter, a receiver, sensors, sensing circuitry, therapy circuitry, a power supply, and other suitable components. The housing is configured to be implanted in a patient (such as a patient).

[0049] exist Figure 2 In the example shown, EV-ICD 209 is implanted outside the patient's left thorax, e.g., under the skin and outside the chest cavity (subcutaneous or submuscular). In some cases, EV-ICD 209 may be implanted between the patient's left posterior axillary line and left anterior axillary line. However, EV-ICD 209 may be implanted at other extrathoracic locations on the patient, as described later, and in some cases, may be implanted within the chest cavity.

[0050] In some examples, at least a portion of the lead 212 may be implanted within the chest cavity, e.g., Figure 2 is shown implanted between the sternum 252 and the heart. In other examples, the lead 212 may be implanted outside the chest cavity, for example, under the skin but outside the ribs, or in other locations, depending on the patient's anatomy and condition. In still other examples, the lead 212 may be implanted within the heart (e.g., intracardially or transvenously) or attached to the heart (e.g., epicardially or pericardially). The lead 212 may include a proximal end 214 having one or more connectors 234 to electrically couple the lead 212 to the EV-ICD 209. In some examples, at least a portion of the distal portion 222 may define a wavy configuration from the distal end to the proximal end 214. The lead 212 may include defibrillation electrode segments 228a and 228b (collectively, segments 228) spaced a distance from one another along the length of the distal portion 222. Although Figure 2Two such segments 228 are depicted, but in other examples, the lead 212 may include one or more segments 228. In some examples, the segments 228 may function as separate defibrillation electrodes. Each segment 228 may have its own separate conductor, allowing voltage to be applied to each electrode individually or simultaneously.

[0051] The defibrillation electrode segments 228 can be disposed around or within the lead body 212 at the distal portion 222, or alternatively, can be embedded within the wall of the lead body 212. In one configuration, the defibrillation electrode segments 228 can be coil electrodes formed from a conductor. The conductor can be formed from one or more conductive polymers, ceramics, metal-polymer composites, semiconductors, metals, or metal alloys, including but not limited to platinum, tantalum, titanium, niobium, zirconium, ruthenium, indium, gold, palladium, iron, zinc, silver, nickel, aluminum, molybdenum, stainless steel, MP35N, carbon, copper, polyaniline, polypyrrole, and combinations of other polymers. In another configuration, each of the defibrillation electrode segments 228 can be a flat ribbon electrode, a paddle electrode, a braided or woven electrode, a mesh electrode, a directional electrode, a patch electrode, or another type of electrode configured to deliver a cardioversion / defibrillation shock to the patient's heart.

[0052] The distal portion 222 can define one or more gaps 220 between adjacent defibrillation zones 228. The gaps 220 can define any length. Where there are more than two defibrillation zones 228, each gap 220 can define the same or substantially the same length as each other gap 220, or can define a different length than the other gaps 220 in the distal portion. In some examples, one or more electrodes 232 can be disposed within a respective gap 220. Figure 2 In the configuration shown, a single electrode 232a is disposed within the gap 220. However, in other examples, there may be more than one electrode 232 within each respective gap 220. Figure 2 In the configuration shown, another electrode 232b is located distal to the defibrillation electrode segment 228a. In other configurations, additional electrodes 232 may be disposed along the distal portion 222 of the lead 212, for example, distal to the defibrillation electrode segment 228b and / or proximal to the electrode segment 228a.

[0053] Electrodes 232a and 232b can be configured to deliver low-voltage electrical pulses to the heart or to sense cardiac electrical activity, such as depolarization and repolarization. Therefore, electrodes 232 may be referred to herein as pacing / sensing electrodes 232. In one configuration, electrodes 232 are ring electrodes. However, in other configurations, electrodes 232 can be any of a variety of different electrode types, including ring electrodes, short coil electrodes, paddle electrodes, hemispherical electrodes, directional electrodes, and the like. Electrodes 232 can each be of the same or different types. Electrodes 232 can be electrically isolated from adjacent defibrillation segments 228 by including an electrically insulating layer of material between the electrodes 232 and adjacent defibrillation segments 228. Similar to segments 228 described above, each electrode 232 can have its own separate conductor, allowing voltage to be applied to each electrode independently of the other electrodes 232 and segments 28 in the lead 212. In other configurations, each electrode 232 can be coupled to a common conductor, allowing voltage to be applied to each electrode 232 simultaneously.

[0054] IMD 251 is the above Figure 1 The system 200 may be an example of an IMD 12 or IMD 14 described above and may have the same functions and characteristics. In some examples, the IMD 251 may be any other CIED described above, such as a neurostimulator, a drug pump, a pulse wave velocity detector, or a similar medical device. In some examples, the IMD 251 may be configured to measure cardiac activity. In some examples, the system 200 may measure arrhythmia precursors, such as the above-mentioned STV, based on one or both of the EV-ICD 209 vector and the electrogram (EGM) from the IMD 251. In some cases, using a combined measurement to measure arrhythmia precursors may provide increased sensitivity. If the system 200 detects an arrhythmia precursor, the IMD 251 may be configured to deliver antiarrhythmic therapy, such as overdrive pacing to reduce STV or other precursors and avoid VT / VF. In some examples, the detected precursor may also trigger the IMD 251 to administer conduction system anti-tachycardia pacing (ATP).

[0055] In some examples, EV-ICD 209 can administer antiarrhythmic therapy. Some patients may be sensitive to pacing using EV-ICD leads, for example, overdrive pacing delivered by electrodes 232. Pacing thresholds via electrodes 232 can be relatively high compared to intracardiac leads or leadless devices such as IMD 251. Therefore, in some examples, overdrive pacing or other high-speed pacing performed by IMD 251 can be superior to such pacing from EV-ICD 209.

[0056] Overdrive pacing may differ from anti-tachycardia pacing in that it may be lower energy and less perceptible to the patient. Overdrive pacing may help prevent tachyarrhythmias, where ATP may be used to pace patient 226 out of an ongoing tachyarrhythmia event. In some examples, overdrive pacing may be described as system 200 responding to changes in heart rate or other sensed cardiac activity by accelerating the pacing rate until the pacing rate reaches a stable paced rhythm slightly faster than the spontaneous rate. After each sensed non-refractory cardiac event, the pacing device of system 200 (e.g., IMD 251 or IMD 209) may shorten the pacing interval by a programmed decremental value. If the next cardiac event is another non-refractory sensed event, the pacing interval is further decremented. This overdrive function may continue until the pacing rate exceeds the spontaneous rate, resulting in a paced rhythm. After 100% of the programmable pacing period, the pacing device may gradually decrease the pacing rate, similar to a smoothing function, to search for the next spontaneous sinus cycle. High-speed pacing differs from overdrive pacing in that high-speed pacing can be at a preset pacing rate rather than an accelerated pacing rate where the pace is paced faster until the pacing rate stabilizes as in overdrive pacing.

[0057] In some examples, as with any device of the present disclosure, the EV-ICD 209 or IMD 251 can also adjust pacing parameters during overdrive pacing to increase pacing energy, such as increasing pacing amplitude, pulse width, or some combination of pacing parameters to deliver higher energy pacing pulses. Early recurrence (such as atrial or ventricular tachycardia, flutter, or fibrillation episodes) within about ten minutes after termination of a tachyarrhythmia may be the cause of some paroxysmal tachyarrhythmia episodes in some patients. In some examples, the system 200 can be configured to deliver overdrive pacing after termination of a tachyarrhythmia episode.

[0058] In some examples, the EV-ICD 209 or IMD 251 of the system 200 can measure PVC burden as a precursor to arrhythmia. Figure 1 As stated, Figure 1System 10 or any other example in the present disclosure may also perform the same or similar functions. In other examples, PVC load may trigger other algorithms, such as a short-term variability algorithm for VT / VF prediction. PVC load may be defined as the percentage or other quantity of PVCs to the total number of QRS complexes during a time period (e.g., 24 hours). In the case of multiple PVC morphologies, the predominant morphology of bundle branch block and QRS duration may be used for analysis. In patients presenting for clinical care due to heart failure and PVCs, a higher PVC load may indicate a risk factor. Patients with a high PVC load (e.g., more than ten percent of total heartbeats) may benefit from an assessment of their systolic function. Patients with a very high PVC load (e.g., more than 20% of total heartbeats) may have an increased risk of arrhythmia-induced cardiomyopathy. In some examples, one or more components of system 200 may assess patient 226's cardiac activity for PVC load and trigger actions based on one or more thresholds. For example, a first threshold may trigger an STV algorithm or some other algorithm to confirm that the patient may be at risk of an imminent arrhythmia. The second threshold (eg, a higher percentage than the first threshold) can trigger one or more of the above-described anti-tachyarrhythmia therapies, such as overdrive pacing.

[0059] In the present disclosure, an "imminent" onset of an arrhythmia means a likelihood of the arrhythmia occurring within seconds, minutes, or hours of detecting an indication of the onset of an arrhythmia. In some examples, and depending on the patient, the particular indication, and other factors, the processing circuitry of the disclosed system can automatically take different actions in response to detecting the indication. As described above, the actions can range from confirming the indication to administering non-shock anti-tachyarrhythmia therapy.

[0060] In some examples, the STV algorithm of the present disclosure may include a determination as to whether the STV metric meets one or more treatment delivery thresholds. Additionally, or alternatively, the STV algorithm may include identifying one or more trends in the STV metric over one or more days or one or more weeks and / or one or more comparisons of the STV metric to an STV metric determined for a previous day. For example, one or more patient-specific treatment delivery thresholds may be determined based on an increase (e.g., a fixed value or percentage) over a programmed patient's baseline STV value over the course of one or more days. As another example, one or more patient-specific treatment delivery thresholds may be determined based on a trending increase (e.g., a fixed value or percentage) in the patient's STV value over the previous day or days.

[0061] As another example, one or more patient-specific therapy delivery thresholds may be automatically programmed after the device detects an arrhythmic event. In such an example, the device may detect an arrhythmic event that was not predicted in advance and then, based on the patient's STV and the detected arrhythmic event,

[0062] Automatically adjust and reprogram the patient's STV threshold. Additionally, the determination of whether the STV metric meets one or more treatment delivery thresholds can also be based on the patient population to which the patient belongs. For example, treatment delivery thresholds can be based on different patient populations (such as age, gender, amount of scar tissue, comorbidities, etc.), and the system can determine a patient-specific treatment delivery threshold based on the patient's membership in one or more patient populations.

[0063] In some examples, system 200 may measure the number, frequency, or some similar metric of non-sustained ventricular tachycardias (NSVTs) as a precursor to a tachyarrhythmia in patient 226. Metrics of non-sustained arrhythmias in individual patients may be used to predict the occurrence of sustained arrhythmias. Variables of interest for such metrics may include, but are not limited to, the number of non-sustained arrhythmias that occur during a specified time period, the duration of the non-sustained arrhythmias, the characteristics of the atrial and / or ventricular septa during the non-sustained arrhythmias, and the EGM morphology during the non-sustained arrhythmias. One or more of these variables may be used to determine one or more non-sustained arrhythmia metrics. The metrics may then be used for other device operations, such as a precursor to delivering one or more anti-tachyarrhythmia therapies described above.

[0064] In some examples, a metric for NSVT may reflect changes in the frequency or duration of non-sustained arrhythmias, which may indicate changes in the factors responsible for triggering sustained arrhythmias. Additional examples of such metrics may include the frequency of non-sustained arrhythmia episodes, determined as the number of episodes occurring within a predetermined amount of time. Another metric may be the average duration of a given number of non-sustained episodes, or the average of all non-sustained episodes occurring within a predetermined amount of time (such as 20, 30, or some other number). Another example metric may include an NSVT index, which is defined as the product of the number of NSVT episodes / day multiplied by the average number of heartbeats per episode (i.e., the total number of NSVT heartbeats per day (total heartbeats / day)) and may indicate the severity of the NSVT incidence. Other example metrics may be equal to the value of an episode counter and represent the frequency of non-sustained arrhythmia episodes during a timer period. Another metric may be calculated as the average of the stored episode durations, or the total number of non-sustained arrhythmia intervals that occurred during a timer interval, calculated as the sum of all stored episode durations. The metric can be the product of the number of episodes detected and the average of the durations of all episodes. The processing circuitry of system 200 can determine one or more non-sustained arrhythmia metrics based on the stored cycle interval and / or EGM morphology template data. The non-sustained arrhythmia metric can be calculated as an average of the collected cycle interval data or an average of characteristic features of the EGM template. The processing circuitry of system 200 can use any such metric or combination of metrics as a precursor to an arrhythmia and trigger further action, such as additional analysis by another algorithm or by delivering any of the above-described anti-tachyarrhythmia therapies.

[0065] Figure 3 is a conceptual diagram illustrating an example system for predicting cardiac arrhythmias, including a wearable medical device, in accordance with one or more techniques of this disclosure. Figure 3 The system 300 in the example of Figure 1 and Figure 2 Another example of system 10 and system 200 described separately. Figure 3 In the example of FIG, system 300 includes wearable garment 302, one or more other wearable devices 322 and 326, portable computing device 328, and one or more implantable devices or other wearable devices, such as IMD 314. Similar to systems 10 and 200, system 300 may also include an external computing device in addition to portable computing device 328, and any of wearable garment 302, wearable devices 322 and 326, and portable computing device 328 may communicate with each other via a network ( Figure 3 IMD 314 can perform any of the functions and has the same Figure 1and Figure 2 The same or similar features are described for IMD 12, IMD 14, EV-ICD 209, and IMD 251.

[0066] Wearable clothing 302 is a medical device. Figure 3 In the example of FIG. 3 , it includes a plurality of sensing electrodes 340, 342, 344, 346 located on the garment so that the plurality of sensing electrodes receive bioelectrical signals from the skin of the patient 308. The garment 302 also includes processing circuitry 310 and therapy delivery electrodes 330. The garment 302 may also include other therapy delivery electrodes (e.g., along the sides or back of the patient 308). Figure 3 In some examples, garment 302 may include a mechanical sensor configured to output an indication of a compression level of garment 302 and a device configured to adjust the compression level of the garment ( Figure 3 (not shown) Power source 360 ​​can provide power to the components of wearable garment 302. In some examples, power source 360 ​​can be a replaceable or rechargeable battery. In some examples, power source 360 ​​can be mounted on garment 302. In other examples, power source 360 ​​can be carried externally and connected to garment 302, such as in a separate waist bag, purse, etc.

[0067] Processing circuit 310 can be attached to garment 302 and operatively coupled to the mechanical sensor, sensing electrodes 340, 342, 344, and 346, and a device for adjusting the compression level of garment 302. Processing circuit 310 can be an example of a programmable processor, which may include any one or more of a microcontroller (MCU) (e.g., a computer on a single integrated circuit containing a processor core, memory, and programmable input / output peripherals), a microprocessor (μP) (e.g., a central processing unit (CPU) on a single integrated circuit (IC)), a controller, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a system-on-chip (SoC), or equivalent discrete or integrated logic circuits. A programmable processor can be an integrated circuit, i.e., an integrated processing circuit, and the integrated processing circuit can be implemented as a fixed hardware processing circuit, a programmable processing circuit, and / or a combination of fixed and programmable processing circuits. Therefore, as used herein, the terms "processing circuit," "processor," or "controller" can refer to any one or more of the foregoing structures or any other structure that can be used to perform the techniques described herein.

[0068] Examples of memory may include any type of computer-readable storage medium, such as random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, and similar devices. In some examples, the computer-readable storage medium may store instructions that cause the processing circuit to perform the functions described herein. In some examples, the computer-readable storage medium may store data, such as configuration information, temporary values, and other types of data used to perform the functions of the present disclosure.

[0069] exist Figure 3 In the example of FIG, treatment electrode 330 and sensing electrodes 340, 342, 344, and 346 are configured to be placed in contact with the patient's skin and held in place by a compression member, such as garment 302. Both treatment electrode 330 and sensing electrodes 340, 342, 344, and 346 may be adhesive-free. Electrodes held in place solely by compression from garment 302 may improve patient comfort compared to electrodes held in place by adhesive. Although in Figure 3 In the example of FIG, four sensing electrodes and three therapy electrodes are depicted, but garment 302 may include any number of sensing electrodes or therapy electrodes. The number and location of the electrodes may depend on the patient's anatomy and the configuration that provides the best signal quality.

[0070] Figure 3 The example depicts sensing electrodes 342 and 346 as substantially disk-shaped electrodes, and sensing electrodes 344 and 340 as substantially ring-shaped electrodes surrounding electrodes 342 and 346. For example, Figure 3 Sense electrode 342 is depicted as a disk surrounded by a ring of electrode 340. In other examples, electrodes 340, 342, 344, and 346 can be any substantially circular shape, such as an ellipse, an octagon, or the like. In other examples, electrodes 340, 342, 344, and 346 can be other geometric shapes, such as a square or a rectangle. In contrast, other examples of multiple sense electrodes can arrange the electrodes to be approximately the same size and with equal or approximately equal spacing between the electrodes.

[0071] Electrodes 342 and 340 form a concentric arrangement and can behave as Laplace bipolar electrodes. However, electrodes 342 and 340 are connected to the circuit of system 300 in a manner completely different from the high side and low side of a bipolar electrode. In the present disclosure, electrode 342 and electrode 346 are connected to a circuit that outputs an impedance measurement signal. In other words, a pair of electrodes 342 and 346 is configured to output an impedance measurement signal. In some examples, the impedance measurement signal may be a constant current signal. In other examples, the impedance measurement signal may be a high frequency signal (e.g., approximately 8 kHz to 16 kHz).

[0072] The third electrode 344 and the fourth electrode 340 can be connected to the high-side input and the low-side input of the amplifier to measure voltage. In contrast, a bipolar Laplace electrode connects the inner disk electrode and the outer ring electrode to the high side and the low side of the amplifier to measure voltage. In some examples, the impedance measurement signal can be injected into the electrode 342 and returned from the electrode 346, or vice versa. The sensing circuit connected to the sensing electrodes 340 and 344 can measure the induced voltage in the patient's tissue caused by the impedance measurement signal. The measured induced voltage can provide the processing circuit 310 with an indication of the bioimpedance of the patient's tissue. In some examples, the sensing circuit can detect whether the electrode is not connected to the patient's tissue. For example, if the induced voltage is outside the threshold range, the electrode may be disconnected from the body.

[0073] like Figure 3 As shown, electrodes 344 and 340 can be separated and spaced apart at different locations relative to heart 312 and can sense electrocardiogram (ECG) signals and bioimpedance signals from patient 308. Sensing electrodes 340, 342, 344, and 346 can also measure bioelectrical signals related to bioimpedance, fluid status monitoring, heart failure, sleep apnea, ischemia detection, lead continuity detection (also known as lead disconnect detection), and arrhythmias such as atrial fibrillation (AF), ventricular tachycardia (VT), ventricular fibrillation (VF), etc. In some examples, electrodes 340, 342, 344, and 346 can be located relative to Figure 3 Different other positions are shown, such as laterally or posteriorly relative to the heart 312.

[0074] In some examples, clothing 302 may also include a motion sensor, such as an accelerometer or similar sensor ( Figure 2(not shown). One or more motion sensors may be included in the processing circuit 310 and / or located elsewhere in the garment 302. The motion sensors of the present disclosure may be configured to determine one or more of the patient's movement or posture. For example, the patient 308 may increase his activity level, such as running, jumping, etc., which may increase the movement between the sensing electrodes 340, 342, 344, and 346 and the patient's skin. In addition, the patient 308 may change his posture from upright to sitting or supine. In some examples, the external devices 322 and 326 and the portable computing device 328 may include sensors that indicate movement, temperature, etc. The processing circuit 310 may receive an indication of the patient's 308 movement and / or posture, and in some examples, may dynamically adjust the compression level of the garment 302 based on one or more of an indication of the compression level from the mechanical sensor, a received bioelectrical signal, or an indication from the motion sensor.

[0075] In operation, the processing circuitry of any of the components of system 300 and any other systems of the present disclosure (such as those described above with respect to Figure 1 and Figure 2 The systems 100 and 200 described herein can sense and detect one or more precursors to a tachyarrhythmia and trigger a non-shock response. Figure 1 and Figure 2 As described above, the non-shock response may include triggering a second detection technology to confirm the presence of a precursor to a tachyarrhythmia. In some examples, the initial detection technology may consume relatively low energy, while one or more triggered subsequent detection technologies may use relatively high energy compared to the initial detection technology. For example, based on a first detection algorithm (such as the one described above with respect to Figure 1 Based on the results of the STV detection algorithm described above, the processing circuitry of system 300 may trigger a second detection algorithm. The second detection algorithm may be executed on the same device or a different device. The second detection algorithm may consume relatively more resources than the first algorithm and provide relatively higher sensitivity and / or higher specificity than the first algorithm.

[0076] In other examples, the non-shock response may include that the detection device (e.g., IMD 314) may send a message to an application on the patient's smartphone or similar device to take one or more actions. For example, IMD 314 may send an electronic message that causes portable computing device 328 to warn patient 308 to take some action to avoid or prevent a possible impending arrhythmia. Depending on the condition of patient 308, some examples of actions may include increasing oral antiarrhythmic medication for a specified period of time, self-injecting antiarrhythmic medication (such as adenosine, atropine, lidocaine, etc.), warning to stop stressful activities or exercise, warning to stop caffeine intake, warning to put on a wearable defibrillator (such as garment 302), or warning to take some other similar action.

[0077] One such action may include informing the patient to apply a low-level electromagnetic field based on detecting a precursor to an arrhythmia. In some examples, applying a low-level pulsed electromagnetic field (EMF) with an intensity in the microgauss range may increase the threshold at which an arrhythmia may occur or reduce the duration of an episode. In some examples, applying the EMF to a specific anatomical location (such as the vagus nerve trunk in the neck or the chest area near the heart) may provide a desired anti-arrhythmic response in the patient. In some examples, garment 302 may include a device for applying the EMF to patient 308.

[0078] In other examples, as discussed above with respect to Figure 1 As described, a medical device (such as IMD 314) of system 300 having sensing circuitry configured to sense cardiac activity of a patient can detect a ventricular tachyarrhythmia or other precursor to a cardiac arrhythmia. In response to detecting a precursor to a tachyarrhythmia, the device can output a communication to a second device that can trigger the second device to deliver a non-shock therapy to suppress the onset of the ventricular tachyarrhythmia. As described above with respect to Figure 1 and Figure 2 As described above, in some examples, the second device may include a pump and a fluid reservoir, and the non-electrical therapy may include delivering the fluid from the reservoir to the patient. In other examples, the non-electrical therapy may include applying electrical stimulation therapy to neural tissue and / or tissue of one or more organs of the patient. The organs may include the adrenal glands, the liver, or some other organ.

[0079] Figure 4 is a conceptual diagram illustrating neural tissue of a patient according to one or more techniques of the present disclosure. Figure 4 A neurostimulator (not shown) can apply electrical stimulation therapy to Figure 4 In other examples, the neurostimulator can apply electrical stimulation therapy to one or more areas of the patient as shown. Figure 4 Other neural tissue of the patient not shown, including brain tissue stimulation, such as deep brain stimulation (DBS), spinal cord stimulation (SCS), tibial nerve stimulation, subcutaneous nerve stimulation, or some other neural tissue. The neurostimulator can be an implantable neurostimulator (INS), a wearable device, or some similar neurostimulator.

[0080] exist Figure 4 In an example, a neurostimulator can be delivered via one or more implanted leads ( Figure 4 In some examples according to the present disclosure, a lead may be placed transvascularly such that the lead passes through the vessel wall from within a blood vessel of the patient 412 so that stimulation and sensing electrodes on the lead may terminate near the target neural tissue stimulation site. Figure 4The examples describe placement in the context of stimulating the vagus nerve in a patient's neck, but in other examples, the leads and any attached electrodes may also be arranged for vagus nerve stimulation, for example, in the chest and / or adjacent to the esophagus or other nerves (such as the thoracic nerves).

[0081] The extravascular lead placement technique according to the present disclosure provides for the placement of a lead for neural tissue stimulation and / or neural signal sensing using an implantation procedure that is less invasive and does not require anchoring the lead at or near its distal end. Generally speaking, the disclosed technique includes placing a portion of a medical lead having an electrode in an extravascular space within a sheath of tissue within a patient 412 and adjacent to neural tissue within the sheath of the same tissue. The lead is anchored at least partially offset from the electrode outside the sheath.

[0082] Figure 4 The vagus nerve 450 is shown, which includes many branches, such as the pharyngeal and laryngeal branches 452, the cardiac branches 454, and the gastric and pancreaticoduodenal branches ( Figure 4 The vagus nerve 450 originates in the brainstem, extends within the neck through the carotid sheath 156 along with the jugular vein 158 and common carotid artery 160, and then extends adjacent to the esophagus to the thoracic and abdominal viscera.

[0083] The vagus nerve 450 provides primary parasympathetic innervation to the chest and most abdominal organs. For example, the vagus nerve 450 provides parasympathetic innervation to the heart, and stimulation of the nerve has been shown to drive the parasympathetic nervous system, thereby overcoming accelerated sympathetic tone, which may be exhibited by patients suffering from various tachycardia conditions and heart failure. In one such tachycardia application, the efferent fibers of the vagus nerve, such as one or more upper and / or lower cardiac branches, can be electrically stimulated to manage accelerated arrhythmias. Vagus nerve stimulation can also have an afferent effect, which causes changes in neural reflexes that affect heart rate. In addition to cardiac innervation, the vagus nerve 450 is also responsible for such various tasks, such as gastrointestinal motility, sweating, and muscle movements associated with speech. Electrical stimulation of the vagus nerve 450 can be used not only to treat heart failure and arrhythmia conditions, but also to treat a variety of other conditions, including, for example, depression, epilepsy, and various gastrointestinal conditions.

[0084] In other examples, in response to a trigger from a cardiac monitoring device that detects a precursor to an arrhythmia, the neurostimulator can apply electrical stimulation therapy to the stellate ganglion 440. For example, some patients may have increased short-term variability with left stellate ganglion activity. The disclosed system can use an indication of STV to titrate the output from an implantable neurostimulator that can deliver a pulse sequence to produce a stellate ganglion block. Stellate ganglion block ablation is an intervention for refractory VT storm.

[0085] In other examples, a single device may be connected to both cardiac monitoring and therapy delivery electrodes and neural monitoring and therapy delivery electrodes ( Figure 4 (not shown). A single device can be connected to one or more cardiac leads including electrodes for sensing and / or therapy and one or more neural leads having electrodes for sensing and / or therapy. A single device can perform any one or a combination of the functions described herein, such as using a detection technology that consumes relatively few resources to trigger one or more additional detection technologies that consume relatively more resources and can provide relatively higher sensitivity and / or higher specificity to determine whether a patient indicates a precursor to an arrhythmia.

[0086] Figure 5 is a block diagram illustrating an example medical device in accordance with one or more techniques of this disclosure. Figure 5 The IMD500 shows Figure 1 IMD 14 or IMD 12 of medical system 10, and Figure 2 IMD 209 and IMD 251, and Figure 3 IMD 314 and Clothing 302 and about Figure 4 One possible example configuration of the apparatus associated with the described operations.

[0087] In the example shown, IMD 500 includes a power source 532, processing circuitry 534, memory 536, communication circuitry 538, a communication antenna 540, sensing circuitry 542, a sensor 544, therapy delivery circuitry 543, and electrodes 548A and 548B (collectively, "electrodes 548"). Although the example shown includes two electrodes 548, in other examples, IMD 500 can be coupled to more than two electrodes 548.

[0088] The processing circuitry 534 may include fixed-function circuitry and / or programmable processing circuitry. The processing circuitry 534 may include any one or more of a microprocessor, a controller, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or equivalent discrete or analog logic circuitry. In some examples, the processing circuitry 534 may include multiple components (such as any combination of one or more microprocessors, one or more controllers, one or more DSPs, one or more ASICs, or one or more FPGAs) and other discrete or integrated logic circuitry. The functionality attributed herein to the processing circuitry 534 may be embodied in software, firmware, hardware, or any combination thereof.

[0089] The sensing circuit 542 is coupled to the electrodes 548. The sensing circuit 542 can sense signals from the electrodes 548, for example, to generate a cardiac EGM to facilitate monitoring of the electrical activity of the heart. The processing circuit 534 can receive an indication from the sensing circuit 542 to determine the heart rate or heart rate variability, or to detect arrhythmias (e.g., tachyarrhythmias or bradycardias) via the electrodes 548, the patient's respiratory rhythm, bioimpedance, or other bioelectrical signals, as described above with respect to Figures 1 to 4 Sensing circuit 542 may also monitor signals from sensors 544, which may include one or more accelerometers, pressure sensors, temperature sensors, and / or optical sensors, as examples. In some examples, sensing circuit 542 may include one or more filters and amplifiers for filtering and amplifying signals received from electrodes 548 and / or sensors 544.

[0090] Sensing circuitry 542 and / or processing circuitry 534 can be configured to detect cardiac depolarization (e.g., a P wave for atrial depolarization or an R wave for ventricular depolarization) when the cardiac EGM amplitude exceeds a sensing threshold. In some examples, for cardiac depolarization detection, sensing circuitry 542 can include a rectifier, a filter, an amplifier, a comparator, and / or an analog-to-digital converter. In some examples, sensing circuitry 542 can output an indication to processing circuitry 534 in response to sensing of cardiac depolarization. In this manner, processing circuitry 534 can receive indications of detected cardiac depolarization corresponding to the presence of detected R and P waves in corresponding chambers of the heart. Processing circuitry 534 can use the indications of detected R and P waves to determine depolarization intervals, heart rate, and detect cardiac arrhythmias, such as tachyarrhythmias, bradyarrhythmias, and asystole.

[0091] Sensing circuitry 542 may also provide one or more digitized cardiac EGM signals to processing circuitry 534 for analysis, e.g., for rhythm discrimination. In some examples, processing circuitry 534 may store the digitized cardiac EGMs in memory 536. Processing circuitry 534 of IMD 500 and / or processing circuitry of another device that retrieves data from IMD 500 may analyze the cardiac EGMs.

[0092] In some examples, the IMD 500 may include therapy delivery circuitry 543. The therapy delivery circuitry 543 may be configured to output electrical stimulation therapy to a target tissue of a patient, such as to cardiac tissue, neural tissue, and similar patient tissue. In other examples, the therapy delivery circuitry 543 may include a drug pump that provides antiarrhythmic medication, outputs EMF therapy, or other functions described herein. In some examples, the processing circuitry 534 may control one or more parameters of the electrical stimulation from the therapy delivery circuitry 543 based on the bioelectrical signals sensed by the sensing circuitry 542. For example, the processing circuitry 534 may determine that a ventricular contraction is later than expected, e.g., the duration since the previous contraction exceeds a duration threshold. The processing circuitry may cause the therapy delivery circuitry to output electrical stimulation therapy in the form of pacing pulses to cause the patient's heart to contract, as described above with respect to Figures 1 to 4 Any of the therapeutic delivery described.

[0093] Communication circuitry 538 may include any suitable hardware, firmware, software, or any combination thereof for communicating with another device, such as external computing device 22, another networked computing device, or another IMD or sensor. Under the control of processing circuitry 534, communication circuitry 538 may receive downlink telemetry from external computing device 22 or another device and transmit uplink telemetry to the external computing device or another device via an internal or external antenna, such as antenna 540. In addition, processing circuitry 534 may communicate with an external device, such as an IMD, via a communication interface. Figure 1 external computing device 22) and such as Medtronic The IMD 500 can communicate with networked computing devices via a computer network of a network. Antenna 540 and communication circuit 538 can be configured to send 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. Figure 1 In some examples, processing circuitry 534 may cause communication circuitry 538 to output a communication to trigger the second device to provide non-shock therapy. Similarly, communication circuitry 538 may receive an indication that triggers processing circuitry 534 to cause therapy delivery circuitry 543 to deliver non-shock therapy as described above.

[0094] In some examples, memory 536 includes computer-readable instructions that, when executed by processing circuitry 534, cause IMD 500 and processing circuitry 534 to perform the various functions attributed herein to IMD 500 and processing circuitry 534. Memory 536 can include any volatile, nonvolatile, magnetic, optical, or electrical medium, such as random access memory (RAM), read-only memory (ROM), nonvolatile RAM (NVRAM), electrically erasable programmable ROM (EEPROM), flash memory, or any other digital media. By way of example, memory 536 can store programmed values ​​for one or more operating parameters of IMD 500 and / or data collected by IMD 500, such as posture, heart rate, activity level, respiratory rate, therapy delivery statistics, and other parameters, as well as digitized versions of physiological signals sensed by IMD 500, for transmission to another device using communication circuitry 538.

[0095] exist Figure 5 In the example of FIG5 , power source 532 can be coupled to electronic circuits provided in IMD 500 and configured to provide power to these circuits outside of a charging session (e.g., when not receiving wireless power from the primary coil). Power source 532 can be, for example, a primary battery (a non-rechargeable battery) or a rechargeable battery.

[0096] In the illustrated example, IMD 500 includes processing circuitry 534 and associated memory 536, sensing circuitry 542, therapy delivery circuitry 543, one or more sensors 544, and communication circuitry 538 coupled to antenna 540 as described above. However, IMD 500 need not include all of these components or may include additional components.

[0097] In operation, the IMD 500 and the Figures 1 to 5Any of the described systems and components can perform any one or combination of the functions described in this disclosure. For example, IMD 500 can be configured to reduce energy consumption from power supply 532 by operating at low power when possible and executing higher-power functions when needed (e.g., based on detection of a triggering event). For example, processing circuitry 534 can execute any of the STV algorithms or some other algorithm for a short period of time each day and use the measurements to determine how often and / or how long the algorithm should be activated over the next 24 hours. In other words, the triggering event for executing the precursor detection scheme can be a predetermined time interval, such as a day, a week, a period of hours or minutes, or some similar time interval. Alternatively, the triggering event can trigger a first detection algorithm, causing processing circuitry 534 or some other processing circuitry of systems 10, 200, or 300 described above to execute the first detection algorithm. Then, based on the results of the first detection algorithm, the processing circuitry can execute a second detection algorithm, which may consume relatively more resources than the first detection algorithm but may provide relatively higher sensitivity and / or higher specificity than the first detection algorithm. In some examples, the second detection algorithm may also consider different factors than the first algorithm to confirm or reject the presence of a proarrhythmia. Along with any of the above-described STV algorithms, other examples of detection algorithms may include artificial intelligence (AI) and periodic repolarization dynamics (PRD).

[0098] In some examples, processing circuitry 534 or processing circuitry of systems 10, 200, and 300 may execute any of a number of algorithms and other programming instructions to perform the operations described above with respect to Figures 1 to 4 functionality described. Some examples of an initial metric or a first algorithm for triggering a second algorithm may include determining whether the PVC load exceeds a PVC load threshold, as described above. In other examples, the processing circuitry 534 may determine a PVC coupling interval and / or compensation pause, for example, compared to a coupling interval threshold. In some examples, either or both of a multifocal PVC and a monofocal PVC may act as a triggering mechanism. In other examples, the processing circuitry of the disclosed system may determine whether the number of NSVTs per day and / or the number of NSVT beats per day meets a threshold, or in other examples, use an NSVT coupling interval. In other examples, the processing circuitry may use other intervals, such as half a day, multiple days, or some other interval. As described above with respect to Figure 1 and Figure 2 As described above, any computing device in the network 250 may analyze device parameters to trigger STV measurements. Figure 2As described above, the processing circuitry of the present disclosure may run the STV algorithm for a short period of time each day (e.g., in the early morning) and use the measurements (and changes relative to previous days) to determine how often and / or how long the algorithm should be turned on over the next 24 hours or some other interval. In other examples, as described above with respect to Figure 1 As described, the processing circuitry may use T wave alternations and / or T wave morphology changes over a short period of time (e.g., in the early morning) and use this measurement in conjunction with previous daily trends to determine the frequency and / or duration that the algorithm should be turned on within some future interval.

[0099] As described above, the processing circuitry of the present disclosure may use any combination of the above to trigger some subsequent measurements, or directly trigger some of the above non-shock therapies. For example, the processing circuitry may use a combination of the PVC load and NSVT metrics to trigger subsequent measurements (such as an STV algorithm) to confirm a tachyarrhythmia precursor, or to trigger some non-shock therapies. In other examples, the processing circuitry may use any combination of the above metrics and patient-specific information (such as comorbidities, age, sex, BMI, right ventricular ejection fraction (LVEF), left ventricular ejection fraction (LVEF), other structural heart disease (SHD), or some other patient information) to customize the device response to possible tachyarrhythmia precursors.

[0100] Figure 6 It is shown that the Figure 1 An example of an ECG signal sensed by IMD 12 and IMD 14 is shown. As depicted, each individual cardiac cycle 601a, 601b within the ECG signal includes distinguishable characteristics. For example, Figure 6 The cardiac cycle includes P, Q, R, S, T, and U waves or characteristics. One or more of these ECG signal characteristics can be processed and / or analyzed to determine one or more indicators of a patient's health, such as determining at least one interval duration and / or determining at least one heart rate signal including at least one indication of at least one duration time interval.

[0101] The processing circuitry of the disclosed system may be adapted to detect the occurrence of an R wave of an ECG signal representative of a cardiac cycle via one or more sense amplifiers, as described above with respect to Figure 4 Processing circuitry of the present disclosure (e.g., processing circuitry of IMD 500) can utilize R waves to determine one or more interval durations representative of the timing of the cardiac cycle. In one example, the interval duration can be determined based on the amount of time between detections of RR intervals 611 or consecutive R waves, such as Figure 6 For the purpose of determining the interval duration (eg, PP interval 612 or PR interval 613), other characteristics of the ECG signal may alternatively be detected, such as Figure 6 The variability of the QT interval 616 and the ST interval 618 can provide information about the precursors of possible tachyarrhythmias. In the present disclosure, the ST interval 618 may also be referred to as the activation recovery interval 618.

[0102] In some cases, the patient's heart rate may include interval durations that are longer or shorter than other interval durations. As described above, the interval durations of the patient's heart rate may be processed and / or analyzed, and variations in interval durations, also known as heart rate variability (HRV), may be utilized by an internal or external medical device, a physician, or other user to predict or detect one or more autonomic conditions of the patient. Furthermore, in response to the detection, processing, and / or analysis of the HRV of the patient's heart rate, one or more of various treatments may be initiated or titrated to remedy or ameliorate one or more detected autonomic conditions, as described above. Additionally, as described above with respect to Figure 1 As described, the processing circuitry of the disclosed medical system can analyze variability in amplitude, morphology, and other factors along with temporal variability.

[0103] Figure 7 is a flowchart illustrating example operations of a system according to one or more techniques of this disclosure. In some examples, Figure 7 The processing circuit in the description of may refer to the processing circuit of one of the components of the system of the present disclosure. In other examples, Figure 7 One or more steps in the box or Figure 7 Parts of the frame can be distributed between several components, for example, some sensors can be Figure 1 The IMD 12 performs the analysis, while some analysis can be performed by the server 24.

[0104] like Figure 7 As shown, the sensing circuit of the medical system of the present disclosure can sense the patient's cardiac and / or neural activity (700). The sensing circuit can be connected to the patient's heart and / or neural activity (700) via the above-mentioned Figures 1 to 5 Any of the electrodes or other sensors on the device receives bioelectrical signals from the patient 26, such as Figure 5 The electrodes 548A and 548B, accelerometer 549, hemodynamic sensor, temperature sensor and other sensors depicted in Figure 7 not shown).

[0105] The processing circuitry of one or more components of the disclosed systems may be configured to sense cardiac activity of a patient using a medical device (e.g., Figure 5Sensing circuitry of the IMD 500 receives an indication of sensed cardiac activity (702). Based on the sensed cardiac activity, processing circuitry may detect a precursor to a ventricular tachyarrhythmia (704). In some examples, detecting a precursor to a ventricular tachyarrhythmia includes detecting a triggering event, such as Figure 7 Short-term variability in the ARI 618, expiration of the timer, or the above Figures 1 to 5 Any of the other precursors described.

[0106] In response to detecting the triggering event, the processing circuitry may apply a precursory detection algorithm to the sensed cardiac activity (704). In some examples, applying the precursory detection algorithm may include analyzing a recorded and stored EGM of cardiac activity. In other examples, the processing may also or instead apply the precursory detection algorithm to analyze ongoing cardiac activity.

[0107] As described, in some examples, a single device of a medical system (e.g., Figure 5 Processing circuitry 534 of IMD 500 (as depicted in FIG) can receive the sensed cardiac activity, detect precursors or other triggering events, and apply further analysis to the cardiac activity. In other examples, processing circuitry of the first device can detect a first precursor and communicate this to a second device for application of a second precursor detection algorithm. In some examples, the "second" precursor detection algorithm can be the same algorithm, e.g., based on metrics such as NSVT, PVC load, or other examples described above. However, different locations, different sensors, or different timing of the second device may result in different analyses.

[0108] In response to detecting a precursor to a ventricular tachyarrhythmia, the processing circuitry can cause the delivery of a non-shock therapy to suppress the onset of the ventricular tachyarrhythmia (706). In some examples, the processing circuitry can output a communication to a second device. The communication can be configured to trigger the second device to deliver a non-shock therapy to suppress the onset of the ventricular tachyarrhythmia, such as overdrive pacing, fluid delivery, a low-level electric field, a patient alert, or some other action.

[0109] Figure 8 is a flow chart illustrating example operations of a system configured to perform multi-level precursor analysis according to one or more techniques of the present disclosure. Figure 7 As described, in some examples, Figure 8 The processing circuit in the description of may refer to the processing circuit of one or more of the components of the disclosed system. In other examples, Figure 8 One or more steps in the box or Figure 8 Parts of the frame can be distributed between several components. In addition, Figure 7 The steps are the same as Figure 8 The description can focus on Figure 5 To simplify the explanation, however, the example is configured to sense the patient's cardiac activity and the above Figures 1 to 5 Any of the described medical systems may perform Figure 7 and Figure 8 steps.

[0110] exist Figure 8 In the example of , the processing circuit 534 may receive information such as Figure 1 26 . Based on the sensed cardiac activity, processing circuitry of the medical system may detect a first precursor to a ventricular tachyarrhythmia (802). As described above, the precursors may include various indications based on analysis of the sensed cardiac signals. In some examples, the analysis may be performed over a longer period of time, for example, looking for patterns over hours, days, weeks, or some other interval. In other examples, the analysis may be based on a more urgent time period, such as minutes or seconds. The analysis may include comparing the PVC load to a PVC load threshold, or some similar analysis of PVC tracking. Other example precursors may include variability in the cardiac cycle, analysis of the NSVT metric, and the aforementioned analysis of the PVC load threshold. Figure 4 The neural signal.

[0111] In response to detecting the first precursor, the processing circuitry may apply a precursor detection algorithm to the sensed cardiac activity (804). In some examples, the precursor detection algorithm may include the same or similar analysis as the analysis used to detect the first precursor. In other examples, the applied precursor detection algorithm may be a different algorithm. In some examples, the precursor detection algorithm consumes relatively more resources than the first precursor detection algorithm and may provide relatively higher sensitivity and / or higher specificity than the first precursor detection algorithm. In some examples, the processing circuitry may simply perform the same precursor analysis more frequently and / or for a longer duration, which may consume more resources, such as microprocessor wake-up time. For example, the processing circuitry may apply the precursor detection algorithm to the sensed cardiac activity based on a predetermined time interval. Based on the results of the first detection algorithm, the processing circuitry executes the first detection algorithm more frequently than the predetermined time interval. In other examples, the processing circuitry may apply a second precursor detection algorithm or set of algorithms, wherein the second precursor detection algorithm consumes relatively more resources than the first precursor detection algorithm. In this manner, the system may conserve battery power while accurately and reliably detecting and acting on precursors to tachyarrhythmias.

[0112] Based on the first precursor and the applied precursor detection algorithm, the processing circuitry may confirm an indication of an impending onset of ventricular tachycardia (806). As described above, the RR interval and other measurements of the patient's cardiac cycle may not yet indicate a rhythm within the tachycardia range, but may indicate that an arrhythmia is developing or is about to occur.

[0113] In response to detecting an indication that a ventricular tachyarrhythmia is about to occur, the processing circuit causes the delivery of a non-shockable therapy to suppress the onset of the ventricular tachyarrhythmia (808). Figures 1 to 4 As described, in some examples, Figure 8 All steps of can be performed by a single device. The single device can detect precursors, confirm precursors, and deliver any of the non-shock therapies described above, such as overdrive pacing, nerve stimulation, and / or fluid delivery. In other examples, two or more devices of a medical system can perform Figure 8 Any one or more of the steps listed in .

[0114] The technology of the present disclosure is described in the following examples.

[0115] Example 1. A system comprising: a sensing circuit configured to sense cardiac activity of a patient; and a processing circuit configured to: detect a precursor to a ventricular tachyarrhythmia based on the sensed cardiac activity; and in response to detecting the precursor to the ventricular tachyarrhythmia, deliver non-electrical shock therapy to suppress the onset of the ventricular tachyarrhythmia.

[0116] Example 2. The system of Example 1, wherein the non-shock therapy comprises any of: overdrive pacing or high-speed pacing.

[0117] Embodiment 3. The system of embodiments 1 and 2, wherein the non-electrical therapy comprises stimulation of the patient's refractory period.

[0118] Example 4. The system of any one of Examples 1 to 3, wherein the non-electrical shock therapy comprises applying electrical stimulation therapy to the patient's neural tissue.

[0119] Example 5. The system of any one of Examples 1 to 4, wherein the non-electrical therapy is antiarrhythmic neural stimulation, and wherein the neural tissue of the patient comprises one or more of: vagus nerve, stellate ganglion, spinal cord stimulation, and thoracic nerves.

[0120] Example 6. The system of any one of Examples 1 to 5, wherein the non-electrical treatment comprises applying a low level electric field to the patient.

[0121] Embodiment 7. The system of embodiments 1 to 6, wherein the non-electrical therapy comprises delivering fluid from a reservoir of a pump to the patient.

[0122] Example 8. A system according to any one of Examples 1 to 7, the system comprising an implantable medical device (IMD), wherein the IMD includes the sensing circuit and at least a portion of the processing circuit, and wherein the IMD is configured to: detect the precursor to the ventricular tachyarrhythmia; and deliver the non-shock therapy.

[0123] Example 9. The system of Example 8, wherein the IMD comprises a cardiovascular implantable electronic device (CIED) configured to deliver one or more of overdrive pacing or high-speed pacing to the patient.

[0124] Example 10. A system according to any one of Examples 1 to 7, the system comprising: a first medical device configured to apply the non-electric shock therapy to suppress the onset of the ventricular tachyarrhythmia; a second device comprising at least a portion of: a sensing circuit configured to sense the patient's cardiac activity; a communication circuit of the system, wherein the communication circuit is configured to communicate between the first device and the second device; and a processing circuit, wherein the processing circuit of the second device is configured to: detect a precursor to a ventricular tachyarrhythmia based on the sensed cardiac activity; and in response to detecting the precursor to the ventricular tachyarrhythmia, output a communication to the first device, the communication being configured to trigger the first device to apply the non-electric shock therapy to suppress the onset of the ventricular tachyarrhythmia.

[0125] Embodiment 11. The method of embodiment 10, wherein the second medical device is an implantable medical device (IMD).

[0126] Example 12. The system of Example 11, wherein the first medical device comprises a cardiovascular implantable electronic device (CIED) configured to provide one or more of overdrive pacing or high-speed pacing to the patient.

[0127] Embodiment 13. The system of embodiment 10, wherein the first medical device is a wearable medical device.

[0128] Example 14. A system according to Example 10, wherein the first medical device is an external computing device, wherein the non-electric shock therapy from the external computing device is configured to alert the patient via a user interface, and wherein the alert includes one or more of the following: a recommendation to increase oral antiarrhythmic medication for a predetermined duration; a notification to immediately self-inject an antiarrhythmic substance, the antiarrhythmic substance including: adenosine, atropine or lidocaine; a recommendation to stop stressful activities or exercise; a recommendation to stop caffeine intake; or a notification to wear a wearable cardiac defibrillator.

[0129] Example 15. The system of any one of Examples 1 to 14, wherein the precursor to the ventricular tachyarrhythmia comprises short-term variability (STV) of activation recovery interval (ARI).

[0130] Example 16. A system according to any one of Examples 1 to 15, wherein the precursor to the ventricular tachyarrhythmia includes variability in any portion of the sensed cardiac activity for any one or more of the following: amplitude variability in any portion of the sensed cardiac activity or morphological variability in the sensed cardiac activity.

[0131] Example 17. A system according to any one of Examples 1 to 16, wherein the processing circuit is configured to determine the patient's premature ventricular contraction (PVC) burden based on the sensed cardiac activity, and wherein the precursor includes a PVC burden exceeding a PVC burden threshold.

[0132] Example 18. A system according to any one of Examples 1 to 17, wherein detecting a precursor to a ventricular tachyarrhythmia includes applying a precursor detection algorithm to the sensed cardiac activity; and wherein the processing circuit is configured to apply the precursor detection algorithm in response to detecting a triggering event.

[0133] Example 19. A system according to any one of Examples 1 to 18, wherein the processing circuit is configured to determine the patient's premature ventricular contraction (PVC) load based on the sensed cardiac activity, and wherein the triggering event includes the PVC load exceeding a PVC load threshold.

[0134] Example 20. The system of any one of Examples 1 to 19, wherein the triggering event comprises a metric associated with a non-sustained ventricular tachyarrhythmia (NSVT) event.

[0135] Embodiment 21. A system according to any one of embodiments 1 to 20, wherein the precursor detection algorithm includes a first detection algorithm, wherein the triggering event includes a predetermined time interval, and the processing circuit executes the first detection algorithm based on the predetermined time interval; and wherein, based on the result of the first detection algorithm, the processing circuit executes the first detection algorithm at a frequency higher than the predetermined time interval.

[0136] Embodiment 22. A system according to any one of embodiments 1 to 21, wherein the precursor detection algorithm includes a first detection algorithm, wherein, based on the results of the first detection algorithm, the processing circuit executes a second detection algorithm, and wherein the second detection algorithm: consumes relatively more resources than the first detection algorithm, and achieves relatively higher sensitivity and / or higher specificity than the first detection algorithm.

[0137] Embodiment 23. The system of any one of embodiments 1 to 22, wherein the second detection algorithm is a short term variability (STV) algorithm.

[0138] Embodiment 24. The system of any one of Embodiments 1 to 23, wherein the sensing circuit comprises a hemodynamic monitor.

[0139] Example 25. A method comprising: sensing cardiac activity of a patient by a sensing circuit of a medical system; receiving an indication of the cardiac activity of the patient by a processing circuit of the medical system; detecting by the processing circuit based on the sensed cardiac activity that the sensed cardiac activity includes a precursor to a ventricular tachyarrhythmia; and in response to detecting the precursor to the ventricular tachyarrhythmia, causing the delivery of the non-electrical therapy by the processing circuit to suppress the onset of the ventricular tachyarrhythmia.

[0140] Example 26. The method of Example 25, wherein the non-shock therapy comprises either overdrive pacing or high-speed pacing.

[0141] Embodiment 27. The method of any one of embodiments 25 and 26, wherein the non-electrical shock treatment comprises stimulation of the patient's refractory period.

[0142] Example 28. The method of any one of claims 25 to 27, wherein the non-electrical shock therapy comprises applying electrical stimulation therapy to the patient's neural tissue.

[0143] Embodiment 29. The method of embodiments 25 to 28, wherein the non-electrical shock therapy is antiarrhythmic nerve stimulation, and wherein the patient's neural tissue comprises one or more of the following: vagus nerve, stellate ganglion, spinal cord stimulation, and thoracic nerves.

[0144] Embodiment 30. The method of any one of Embodiments 25 to 29, wherein the non-electrical treatment comprises applying a low level electric field to the patient.

[0145] Embodiment 31. The method of embodiments 25 to 30, wherein the non-electrical therapy comprises delivering fluid from a reservoir of a pump to the patient.

[0146] Example 32. A method according to any one of Examples 25 to 31, the method comprising an implantable medical device (IMD), wherein the IMD comprises the sensing circuit and at least a portion of the processing circuit, and the method further comprising: detecting a precursor to the ventricular tachyarrhythmia by the IMD; and delivering the non-shock therapy by the IMD.

[0147] Example 33. The method of Example 32, wherein the IMD comprises a cardiovascular implantable electronic device (CIED), the method further comprising: delivering one or more of overdrive pacing or high-speed pacing to the patient by the IMD.

[0148] Example 34. A method according to any one of Examples 25 to 33, the method comprising: a first medical device configured to apply the non-electric shock therapy to suppress the onset of ventricular tachyarrhythmia; a second device comprising at least a portion of: the sensing circuit configured to sense the patient's cardiac activity; a communication circuit of the medical system, wherein the communication circuit is configured to communicate between the first device and the second device; and a processing circuit, the method further comprising: detecting, by the processing circuit of the second device, a precursor to a ventricular tachyarrhythmia based on the sensed cardiac activity; and in response to detecting the precursor to the ventricular tachyarrhythmia, initiating, by the processing circuit of the second device, communication with the first device, the communication being configured to trigger the first device to apply the non-electric shock therapy to suppress the onset of the ventricular tachyarrhythmia.

[0149] Embodiment 35. The method of Embodiment 34, wherein the second medical device is an implantable medical device (IMD).

[0150] Example 36. A method according to Example 35, wherein the first medical device comprises a cardiovascular implantable electronic device (CIED), the method further comprising: delivering one or more of overdrive pacing or high-speed pacing to the patient by the first medical device.

[0151] Embodiment 37. The method of embodiment 34, wherein the first medical device is a wearable medical device.

[0152] Example 38. A method according to Example 34, wherein the first medical device is an external computing device, wherein the non-electric shock therapy from the external computing device is configured to alert the patient via a user interface, and wherein the warning includes one or more of the following: a recommendation to increase oral antiarrhythmic medication for a predetermined duration, a notification to immediately self-inject an antiarrhythmic substance (the antiarrhythmic substance includes: adenosine, atropine or lidocaine), a recommendation to stop stressful activities or exercise, a recommendation to stop caffeine intake, or a notification to wear a wearable cardiac defibrillator.

[0153] Embodiment 39. The method of any one of embodiments 25 to 38, wherein the precursor to ventricular tachyarrhythmia comprises short-term variability (STV) of activation recovery interval (ARI).

[0154] Example 40. A method according to any one of Examples 25 to 39, wherein the precursor to the ventricular tachyarrhythmia includes variability in any portion of the sensed cardiac activity for any one or more of: amplitude variability in any portion of the sensed cardiac activity or morphological variability in the sensed cardiac activity.

[0155] Example 41. A method according to any one of Examples 25 to 40, wherein the processing circuit is configured to determine the patient's premature ventricular contraction (PVC) load based on the sensed cardiac activity, and wherein the precursor includes a PVC load exceeding a PVC load threshold.

[0156] Example 42. A method according to any one of Examples 25 to 41, wherein detecting a precursor to a ventricular tachyarrhythmia includes applying a precursor detection algorithm to the sensed cardiac activity, the method further comprising applying the precursor detection algorithm by the processing circuit of the medical system in response to detecting a triggering event.

[0157] Example 43. A method according to any one of Examples 25 to 42, further comprising determining, by the processing circuit, a premature ventricular contraction (PVC) load of the patient based on the sensed cardiac activity, and wherein the triggering event comprises the PVC load exceeding a PVC load threshold.

[0158] Example 44. The system of any one of Examples 25 to 43, wherein the triggering event comprises a metric associated with a non-sustained ventricular tachyarrhythmia (NSVT) event.

[0159] Example 45. A method according to any one of Examples 25 to 44, wherein the precursor detection algorithm includes a first detection algorithm, wherein the triggering event includes a predetermined time interval, the method further comprising: based on the predetermined time interval, executing the first detection algorithm by the processing circuit; and based on the result of the first detection algorithm, executing the first detection algorithm by the processing circuit at a frequency higher than the predetermined time interval.

[0160] Embodiment 46. A method according to any one of Embodiments 25 to 45, wherein the precursor detection algorithm includes a first detection algorithm, the method further comprising: based on the result of the first detection algorithm, executing a second detection algorithm by the processing circuit, and wherein the second detection algorithm: consumes relatively more resources than the first detection algorithm, and achieves relatively higher sensitivity and / or higher specificity than the first detection algorithm.

[0161] Embodiment 47. The method of any one of embodiments 25 to 46, wherein the second detection algorithm is a short term variability (STV) algorithm.

[0162] Embodiment 48. The method of any one of Embodiments 25 to 47, wherein the sensing circuit comprises a hemodynamic monitor.

[0163] Example 49. A non-transitory computer-readable storage medium comprising instructions that, when executed, cause a processing circuit of a computing device to: receive an indication of cardiac activity of a patient from a sensing circuit of a medical system, wherein: the sensing circuit is configured to sense the cardiac activity of the patient and the computing device is a component of the medical system; detect a precursor to a ventricular tachyarrhythmia based on the sensed cardiac activity; and in response to detecting the precursor to the ventricular tachyarrhythmia, deliver non-electrical therapy to suppress the onset of the ventricular tachyarrhythmia.

[0164] Example 50. A method comprising: receiving, by a processing circuit, an indication of sensed cardiac activity from a sensing circuit of a medical system configured to sense cardiac activity of a patient; detecting, by the processing circuit of the medical system, a first precursor of a ventricular tachyarrhythmia based on the sensed cardiac activity, and applying, by the processing circuit, a precursor detection algorithm to the sensed cardiac activity in response to detecting the first precursor; and confirming, by the processing circuit, an indication of an episode of ventricular tachycardia based on the first precursor and the applied precursor detection algorithm; and causing, by the processing circuit, the delivery of non-shock therapy to suppress the episode of ventricular tachyarrhythmia in response to detecting the indication of the episode of ventricular tachyarrhythmia.

[0165] Example 51. A method according to Example 50, wherein the medical system includes an implantable medical device (IMD), wherein the IMD includes the sensing circuit and at least a portion of the processing circuit, and the method further includes: detecting a first precursor of the ventricular tachyarrhythmia by the IMD; applying the precursor detection algorithm by the IMD, and delivering the non-shock therapy by the IMD.

[0166] Example 52. A method according to Examples 50 and 51, wherein the IMD comprises a cardiovascular implantable electronic device (CIED), the method further comprising: delivering the non-electrical therapy comprising one or more of refractory period stimulation, overdrive pacing, or high-speed pacing to the patient by the CIED.

[0167] Example 53. A method according to any one of Examples 50 to 52, wherein the medical system includes a first medical device configured to apply the non-electrical shock therapy to suppress the onset of ventricular tachyarrhythmia; wherein the medical system includes a second medical device, wherein the second medical device includes at least a portion of: the sensing circuit, the sensing circuit configured to sense the patient's cardiac activity; a communication circuit for the medical system, wherein the communication circuit is configured to communicate between at least the first device and the second device; and the processing circuit, wherein the method further includes: in response to detecting the first precursor, applying the precursor detection algorithm by the processing circuit of the second device.

[0168] Example 54. A method according to any one of Examples 50 to 53, wherein applying the precursor detection algorithm includes: causing the communication circuit to output communication to the first device, and the first device receiving the output communication; in response to receiving the output communication, the first device confirms the onset of the ventricular tachyarrhythmia by applying the precursor detection algorithm.

[0169] Example 55. A method according to any one of Examples 50 to 54, wherein applying the precursor detection algorithm includes: applying the precursor detection algorithm by the processing circuit of the second device, thereby confirming the onset of the ventricular tachyarrhythmia by the second device, and the method also includes: causing the communication circuit to output a communication to the first device by the second device, the communication being configured to trigger the first device to deliver the non-electric shock therapy.

[0170] Embodiment 56. The method of any one of Embodiments 50 to 55, wherein the second medical device is an implantable medical device (IMD).

[0171] Example 57. A method according to any one of Examples 50 to 56, wherein the first medical device comprises a cardiovascular implantable electronic device (CIED) configured to provide one or more of refractory period stimulation, overdrive pacing, or high-speed pacing to the patient.

[0172] Embodiment 58. The method of any one of Embodiments 50 to 57, wherein the first medical device is a wearable medical device.

[0173] Example 59. The method of any one of claims 50 to 58, wherein the non-electrical shock therapy comprises applying electrical stimulation therapy to the patient's neural tissue.

[0174] Embodiment 60. The method of any one of claims 50 to 59, wherein the non-electrical shock therapy is antiarrhythmic neural stimulation, and wherein the patient's neural tissue comprises one or more of: vagus nerve, stellate ganglion, spinal cord stimulation, and thoracic nerves.

[0175] Embodiment 61. The method of any one of Claims 50 to 60, wherein the non-electrical treatment comprises applying a low level electric field to the patient.

[0176] Embodiment 62. The method of any one of Claims 50-61, wherein the non-electrical therapy comprises delivering fluid from a reservoir of a pump to the patient.

[0177] Example 63. A method according to any one of claims 50 to 62, wherein the first medical device is an external computing device, wherein the non-electric shock therapy from the external computing device is configured to alert the patient via a user interface, and wherein the warning includes one or more of the following: a recommendation to increase oral antiarrhythmic medication for a predetermined duration, a notification to immediately self-inject an antiarrhythmic substance (the antiarrhythmic substance includes: adenosine, atropine or lidocaine), a recommendation to stop stressful activities or exercise, a recommendation to stop caffeine intake, or a notification to wear a wearable cardiac defibrillator.

[0178] Example 64. A method according to any one of Examples 50 to 63, wherein detecting the first precursor includes applying, by the processing circuit, a second precursor detection algorithm to the sensed cardiac activity; and wherein the precursor detection algorithm includes a second precursor detection algorithm, wherein the second precursor detection algorithm: consumes relatively more resources than the first precursor detection algorithm, and provides relatively higher sensitivity and / or higher specificity than the first precursor detection algorithm.

[0179] Example 65. A method according to any one of Examples 50 to 64, wherein detecting the first precursor includes: based on a predetermined time interval, the processing circuit applying a first precursor detection algorithm to the sensed cardiac activity; and the method also includes: in response to the result of the first detection algorithm, the processing circuit executing the first detection algorithm at a frequency higher than the predetermined time interval.

[0180] Example 66. A method according to any one of Examples 50 to 65, wherein the first precursor includes a premature ventricular contraction (PVC) load based on sensed cardiac activity, the method further comprising applying the precursor detection algorithm when the PVC load exceeds a PVC load threshold.

[0181] Embodiment 67. The method of any one of embodiments 50 to 66, wherein the first precursor comprises a metric associated with a non-sustained ventricular tachyarrhythmia (NSVT) event.

[0182] Example 68. The method of any one of Examples 50 to 67, wherein the first precursor to the ventricular tachyarrhythmia comprises short-term variability (STV) of an activation recovery interval (ARI) of the sensed cardiac activity.

[0183] Example 69. The method of any one of Examples 50 to 68, wherein the first precursor to the ventricular tachyarrhythmia comprises short-term variability (STV) of the QT interval of the sensed cardiac activity.

[0184] Embodiment 70. The method of any one of Embodiments 50 to 69, wherein the sensing circuit comprises a hemodynamic monitor.

[0185] Example 71. A medical system comprising: a sensing circuit configured to sense cardiac activity of a patient; a processing circuit configured to: receive an indication of the sensed cardiac activity from the sensing circuit; detect a first precursor to a ventricular tachyarrhythmia based on the sensed cardiac activity; in response to detecting the first precursor, apply a precursor detection algorithm to the sensed cardiac activity; and based on the first precursor and the applied precursor detection algorithm, confirm by the processing circuit an indication of an episode of ventricular tachycardia; in response to detecting the indication of an episode of ventricular tachyarrhythmia, cause delivery of the non-shock therapy to suppress the episode of the ventricular tachyarrhythmia.

[0186] Example 72. A system according to Example 71, wherein the system includes an implantable medical device (IMD), wherein the IMD includes at least a portion of the sensing circuitry and processing circuitry of the system, and wherein the IMD is configured to: detect a first precursor to the ventricular tachyarrhythmia; apply the precursor detection algorithm, and deliver the non-shock therapy.

[0187] Example 73. A system according to any one of Examples 71 to 72, wherein the IMD comprises a cardiovascular implantable electronic device (CIED) configured to provide one or more of refractory stimulation, overdrive pacing, or high-speed pacing to the patient.

[0188] Example 74. A system according to any one of Examples 71 to 73, wherein the system includes a first medical device configured to apply the non-shock therapy to suppress the onset of ventricular tachyarrhythmia; wherein the system includes a second medical device, the second medical device including at least a portion of: the sensing circuit, the sensing circuit configured to sense the patient's cardiac activity; a communication circuit for the system, wherein the communication circuit is configured to communicate between at least the first device and the second device; and a processing circuit, wherein the processing circuit of the second device is configured to: in response to detecting a first precursor to applying the precursor detection algorithm; and in response to confirming an indication of the onset of ventricular tachycardia, cause the communication circuit to output a message to the first device to apply the non-shock therapy.

[0189] Embodiment 75. The system of any one of Embodiments 71 to 74, wherein applying the precursor detection algorithm comprises: the processing circuit of the second device applying the precursor detection algorithm.

[0190] Example 76. A system according to any one of Examples 71 to 75, wherein applying the precursor detection algorithm includes: causing the communication circuit to output communication to the first medical device, wherein the communication is configured to trigger the first device to apply the precursor detection algorithm to confirm the onset of the ventricular tachyarrhythmia.

[0191] Embodiment 77. The system of any one of Embodiments 71 to 76, wherein the second medical device is an implantable medical device (IMD).

[0192] Example 78. A system according to any one of Examples 71 to 77, wherein the first medical device comprises a cardiovascular implantable electronic device (CIED) configured to provide one or more of refractory period stimulation, overdrive pacing, or high-speed pacing to the patient.

[0193] Embodiment 79. The system of any one of Embodiments 71 to 78, wherein the first medical device is a wearable medical device.

[0194] Example 80. A system according to any one of claims 71 to 79, wherein the non-electrical shock therapy comprises applying electrical stimulation therapy to the patient's neural tissue.

[0195] Example 81. A system according to any one of claims 71 to 80, wherein the non-electrical therapy is antiarrhythmic neural stimulation, and wherein the patient's neural tissue includes one or more of the following: vagus nerve, stellate ganglion, spinal cord stimulation, and thoracic nerves.

[0196] Example 82. A system according to any one of claims 71 to 81, wherein the non-electric treatment comprises applying a low level electric field to the patient.

[0197] Example 83. The system of any one of Claims 71 to 82, wherein the non-electrical therapy comprises delivering fluid from a reservoir of a pump to the patient.

[0198] Example 84. A system according to any one of claims 71 to 83, wherein the first medical device is an external computing device, wherein the non-electric shock therapy from the external computing device is configured to alert the patient via a user interface, and wherein the warning includes one or more of the following: a recommendation to increase oral antiarrhythmic medication for a predetermined duration, a notification to immediately self-inject an antiarrhythmic substance (the antiarrhythmic substance includes: adenosine, atropine or lidocaine), a recommendation to stop stressful activities or exercise, a recommendation to stop caffeine intake, or a notification to wear a wearable cardiac defibrillator.

[0199] Example 85. A system according to any one of Examples 71 to 84, wherein detecting the first precursor includes: applying, by the processing circuit, a first precursor detection algorithm to the sensed cardiac activity; and wherein the precursor detection algorithm includes a second precursor detection algorithm, wherein the second precursor detection algorithm: consumes relatively more resources than the first precursor detection algorithm, and the first precursor detection algorithm provides relatively higher sensitivity and / or higher specificity.

[0200] Example 86. A system according to any one of Examples 71 to 85, wherein detecting the first precursor includes: based on a predetermined time interval, the processing circuit applying a first precursor detection algorithm to the sensed cardiac activity; and wherein, based on the result of the first detection algorithm, the processing circuit executes the first detection algorithm at a frequency higher than the predetermined time interval.

[0201] Example 87. A system according to any one of Examples 71 to 86, wherein the first precursor includes a premature ventricular contraction (PVC) load based on sensed cardiac activity, the system further comprising applying the precursor detection algorithm when the PVC load exceeds a PVC load threshold.

[0202] Example 88. The system of any one of Examples 71 to 87, wherein the first precursor comprises a metric associated with a non-sustained ventricular tachyarrhythmia (NSVT) event.

[0203] Example 89. The system of any one of Examples 71 to 88, wherein the first precursor to the ventricular tachyarrhythmia comprises short-term variability (STV) of an activation recovery interval (ARI) of the sensed cardiac activity.

[0204] Example 90. The system of any one of Examples 71 to 89, wherein the first precursor to the ventricular tachyarrhythmia comprises short-term variability (STV) of the QT interval of the sensed cardiac activity.

[0205] Embodiment 91. A system according to any one of embodiments 71 to 90, wherein the sensing circuit includes a hemodynamic monitor.

[0206] Embodiment 92. A non-transitory computer-readable storage medium comprising instructions that, when executed, cause a processing circuit of a computing device to: receive an indication of cardiac activity of a patient from a sensing circuit of a medical system, wherein: the sensing circuit is configured to sense cardiac activity of the patient and the computing device is a component of the medical system; detect a first precursor to a ventricular tachyarrhythmia based on the sensed cardiac activity; in response to detecting the first precursor, apply a precursor detection algorithm to the sensed cardiac activity; and based on the first precursor and the applied precursor detection algorithm, confirm an indication of an onset of ventricular tachycardia; in response to detecting the indication of an onset of the ventricular tachyarrhythmia, cause the delivery of non-shock therapy to suppress the onset of the ventricular tachyarrhythmia.

[0207] In one or more examples, the above functions can be implemented in hardware, software, firmware, or any combination thereof. For example, Figure 1 and Figure 2The various components of the IMD 12, IMD 14, external computing device 22, IMD 209, etc. may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored or transmitted as one or more instructions or codes on a computer-readable medium and executed by a hardware-based processing unit. Computer-readable media may include computer-readable storage media or communication media, where the computer-readable storage media corresponds to tangible media such as data storage media, where the communication media includes any media that facilitates the transfer of a computer program from one place to another, for example, according to a communication protocol. As such, computer-readable media may generally correspond to: (1) non-transitory tangible computer-readable storage media or (2) communication media such as a signal or carrier wave. Data storage media may be any available media that can be accessed by one or more computers or one or more processors to retrieve instructions, codes, and / or data structures for implementing the techniques described in the present disclosure. A computer program product may include computer-readable media.

[0208] The term "non-transitory" may indicate that the storage medium is not embodied in a carrier wave or propagating signal. In some examples, a non-transitory storage medium may store data that may change over time (e.g., in RAM or cache). By way of example and not limitation, such computer-readable storage media may include random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, hard disk, compact disk ROM (CD-ROM), floppy disk, magnetic cassette, magnetic media, optical media, or other computer system readable media. In some examples, an article of manufacture may include one or more computer-readable storage media.

[0209] Furthermore, any connection is properly referred to as a computer-readable medium. For example, if instructions are sent from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwaves, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwaves are included in the definition of medium. However, it should be understood that the computer-readable storage medium and data storage medium do not include connections, carrier waves, signals, or other temporary media, but are actually non-temporary tangible storage media. Combinations of the above should also be included within the scope of computer-readable media.

[0210] The instructions may be executed by one or more processors, such as one or more DSPs, general purpose microprocessors, ASICs, FPGAs, CPLDs, or other equivalent integrated or discrete logic circuits. Therefore, as used herein, the terms "processor" and "processing circuitry" (such as Figure 5 The processing circuit 534 of the embodiment of the present invention may refer to any of the aforementioned structures or any other structures suitable for the specific implementation of the technology described herein. In addition, these technologies can be fully implemented in one or more circuits or logic elements.

[0211] The techniques of the present disclosure may be implemented in a variety of devices or apparatuses, including integrated circuits (ICs) or collections of ICs (e.g., chipsets). Various components, modules, or units are described in this disclosure to emphasize the functional aspects of an apparatus configured to perform the disclosed techniques, but they do not necessarily need to be implemented by different hardware units. Instead, as described above, the various units may be combined in hardware units in conjunction with appropriate software and / or firmware, or provided by a collection of interoperable hardware units, including one or more processors as described above.

Claims

1. A system, comprising: sensing circuitry configured to sense cardiac activity of the patient; and a processing circuit, the processing circuit being configured to: Detecting precursors to ventricular tachyarrhythmias based on sensed cardiac activity; as well as In response to detecting the precursor to the ventricular tachyarrhythmia, non-shock therapy is delivered to suppress the onset of the ventricular tachyarrhythmia.

2. The system of claim 1, wherein the non-shock therapy comprises one or more of: overdrive pacing, high-speed pacing, refractory stimulation, or electrical stimulation therapy of the patient's neural tissue.

3. The system of claim 2, wherein the non-electrical therapy is antiarrhythmic neurostimulation, and The neural tissue of the patient comprises one or more of the following: vagus nerve, stellate ganglion, spinal cord nerve, and thoracic nerve.

4. The system of claims 1 to 3, wherein the non-electrical treatment comprises applying a low level electric field to the patient.

5. The system according to any one of claims 1 to 4, comprising: a first medical device configured to administer the non-shock therapy to suppress the episode of ventricular tachyarrhythmia; A second device, the second device comprising at least a portion of the following: the sensing circuit, the sensing circuit being configured to sense cardiac activity of the patient; communications circuitry of the system, wherein the communications circuitry is configured to communicate between the first device and the second device; and the processing circuit, wherein the processing circuit of the second device is configured to: Detecting precursors to ventricular tachyarrhythmias based on sensed cardiac activity; as well as In response to detecting the precursor to the ventricular tachyarrhythmia, a communication is output to the first device, the communication configured to trigger the first device to apply the non-shock therapy to suppress the onset of the ventricular tachyarrhythmia.

6. The system of claim 5, wherein the second medical device is an implantable medical device (IMD), and wherein the first medical device comprises a cardiovascular implantable electronic device (CIED) configured to provide one or more of overdrive pacing or high-speed pacing to the patient.

7. The system according to claim 5, wherein the first medical device is an external computing device, wherein the non-shock therapy from the external computing device is configured to alert the patient via a user interface, and The warnings include one or more of the following: It is recommended to add oral antiarrhythmic drugs for the predetermined duration, Notify the patient to immediately self-inject an antiarrhythmic substance, the antiarrhythmic substance including: Adenosine, atropine, or lidocaine, It is recommended to stop stressful activities or exercise, It is recommended to stop caffeine intake, or Notice to put on wearable defibrillator.

8. The system according to any one of claims 1 to 7, wherein the precursor to the ventricular tachyarrhythmia comprises any one of the following: Short-term variability (STV) in the activation recovery interval (ARI), or Variability in any portion of the sensed cardiac activity for any one or more of: amplitude variability in any portion of the sensed cardiac activity or morphology variability in the sensed cardiac activity.

9. The system according to any one of claims 1 to 8, wherein the processing circuit is configured to determine a premature ventricular contraction (PVC) burden of the patient based on the sensed cardiac activity, and The precursor includes a PVC load exceeding a PVC load threshold.

10. The system according to any one of claims 1 to 9, wherein detecting a precursor to a ventricular tachyarrhythmia comprises applying a precursor detection algorithm to the sensed cardiac activity; and Wherein the processing circuit is configured to apply the precursor detection algorithm in response to detecting a triggering event.

11. The system according to any one of claims 1 to 10, wherein the processing circuit is configured to determine a pre-ventricular contraction (PVC) load of the patient based on the sensed cardiac activity, and The trigger event includes the PVC load exceeding a PVC load threshold.

12. The system of any one of claims 1 to 11, wherein the triggering event comprises a metric related to a non-sustained ventricular tachyarrhythmia (NSVT) event.

13. The system according to any one of claims 1 to 12, The precursor detection algorithm includes a first detection algorithm, wherein the triggering event comprises a predetermined time interval, and the processing circuit executes the first detection algorithm based on the predetermined time interval; and in, Based on the result of the first detection algorithm, the processing circuit executes the first detection algorithm at a frequency higher than the predetermined time interval.

14. The system according to any one of claims 1 to 13, The precursor detection algorithm includes a first detection algorithm, in, Based on the results of the first detection algorithm, the processing circuit executes a second detection algorithm, and The second detection algorithm: Compared with the first detection algorithm, it consumes relatively more resources, and Compared with the first detection algorithm, a relatively higher sensitivity and / or higher specificity is achieved.

15. The system according to any one of claims 1 to 14, wherein the second detection algorithm is a short term variability (STV) algorithm.

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