WO2025056995A1

WO2025056995A1 - Notification of end of service for implantable medical device

Info

Publication number: WO2025056995A1
Application number: PCT/IB2024/056990
Authority: WO
Inventors: Wade M. Demmer; Michael L. Graham
Original assignee: Medtronic, Inc.
Priority date: 2023-09-13
Filing date: 2024-07-18
Publication date: 2025-03-20

Abstract

An example operation includes storing in a memory of an implantable medical device a recommended replacement time and/or an activation time for a behavior modification indicator for the implantable medical device. The recommended replacement time and/or the activation time of the behavior modification indicator is based on a target level of performance for the implantable medical device. A determination is made that the recommended replacement time and/or the activation time of the behavior modification indicator has been reached. A wireless notification is transmitted, indicating that the recommended replacement time and/or the activation time of the behavior modification indicator has been reached. In response to receiving a response to the wireless notification within a predetermined amount of time, the implantable medical device is not switched to a single-chamber ventricular sensing and pacing therapy mode.

Description

NOTIFICATION OF END OF SERVICE FOR IMPLANTABLE MEDICAL DEVICE

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63/582,436, filed September 13, 2023, the entire content of which is incorporated herein by reference.

TECHNICAL FIELD

[0002] This disclosure relates to communication of information associated with an end of service for an implantable medical device.

BACKGROUND

[0003] Implantable medical devices (IMDs) may have a limited service lifespan due to factors such as aging electronic components and battery depletion. As a chemical reaction driven power source, such as a battery, is used, the reactants within the power source are consumed. Over time, the performance of the power source decreases, and the power source will eventually need to be recharged or replaced. For many surgically-implanted medical devices, replacement of a drained power source may expose a person to risks associated with surgery. For example, to replace a power source in a pacemaker or similar implanted device, the device containing the power source often needs to be surgically removed, and a new device with a new power source inserted.

SUMMARY

[0004] In general, despite surgical risks, it is desired to replace an IMD before significant performance degradation occurs. For example, IMD performance may degrade to an unacceptable level due to depletion of a battery that supplies power to the IMD.

IMDs may provide a warning or other notification to the patient and/or a clinician so that a surgical procedure to replace the IMD may be scheduled and completed in advance of changes in device performance due, for example, to depletion of the device power source. The time at which such warnings or other notification are provided has sometimes been referred to as an elective replacement interval (ERI), a recommended replacement time (RRT), or a behavior modification indicator. [0005] In general, IMDs provide such warnings or indications of power source depletion upon the occurrence of a predetermined condition. More particularly, IMDs may monitor one or more parameters of the power source or the IMD, such as battery voltage or impedance, and compare the values of these monitored parameters to one or more predetermined thresholds to determine when to provide the warning or indication of power source depletion. Such a threshold is typically a predetermined value that is common for every IMD of a particular model, and selected such that the indication or warning is provided early enough to avoid degradation of device performance due to power source depletion in most circumstances, e.g., for most rates of power source depletion.

[0006] In general, this disclosure is directed towards systems and techniques for providing a wireless notification of an RRT and/or an ERI from an IMD, such as a pacemaker or implantable defibrillator. In some examples described herein, when the IMD reaches the ERI and/or the RRT, the IMD transmits a wireless notification. The IMD waits for a predetermined amount of time to receive a response to the wireless notification. In the event that a response is received within the predetermined amount of time, the IMD 14 does not switch to a ventricular single chamber pacing (VVI) therapy mode at a predetermined number of beats (e.g., 65) beats per minute. In the event that the predetermined amount of time elapses before a response is received, the IMD refrains from turning off the option for the VVI therapy mode, such that the VVI therapy mode will be entered at a VVI time which is not at the end of the predetermined amount of time, but rather at a future time such as 90 days from expected end-of-service for the IMD.

[0007] In a further example described herein, when at least a first amount of time remains prior to an expected end of service for the IMD, a second amount of time less than the first amount of time is provided before the ERI is triggered. For example, the first amount of time may be approximately six months and the second amount of time may be approximately three months. Upon occurrence of the RRT, the IMD transmits a wireless alert which may be received by a monitoring device, sent to a physician, and/or received by a monitoring service. In one example, the receipt of the alert by the physician and/or the alerting service causes a command to be sent to the IMD disabling the ERI. In another example, a notification that the alert was actually reviewed, for example, by a clinician, causes the command to be sent to the IMD disabling the ERI. In yet another example, a notification that replacement surgery to replace the IMD has been scheduled causes the command to be sent to the IMD disabling the ERI.

[0008] In some examples described herein, an implantable medical device includes processing circuitry, and memory operatively coupled to the processing circuitry; wherein the processing circuitry is configured to: store a recommended replacement time and an activation time of a behavior modification indicator for the implantable medical device in the memory, based on a target level of performance for at least one performance characteristic of the implantable medical device; determine that the recommended replacement time has been reached; control telemetry circuitry to transmit a wireless notification indicating that the recommended replacement time has been reached; determine whether a response to the wireless notification is received within a predetermined amount of time from the transmission of the wireless notification; and based on a determination that the response to the transmission of the wireless notification was received within the predetermined amount of time, disabling the behavior modification indicator, the behavior modification indicator comprising a predetermined pacing mode. In a further example, "pacing mode" can mean not only a change, such as from VDD to VVI, but also a change in pacing parameter such as a specific low pacing rate.

[0009] In some examples described herein, a method includes storing a recommended replacement time and an activation time of a behavior modification indicator for the implantable medical device in the memory, based on a target level of performance for at least one performance characteristic of the implantable medical device; determining that the recommended replacement time has been reached; controlling telemetry circuitry to transmit a wireless notification indicating that the recommended replacement time has been reached; determining whether a response to the wireless notification is received within a predetermined amount of time from the transmission of the wireless notification; and disabling the behavior modification indicator, the behavior modification indicator comprising a predetermined pacing mode, based on a determination that the response to the transmission of the wireless notification was received within the predetermined amount of time.

[0010] In some examples described herein, a computer readable medium is encoded with instructions that, if executed by one or more programmable processors of an implantable medical device, cause the implantable medical device to perform operations including: storing, in the computer-readable medium, a recommended replacement time and an activation time of a behavior modification indicator for the implantable medical device, based on a target level of performance for at least one performance characteristic of the implantable medical device; determining that the recommended replacement time has been reached; controlling telemetry circuitry to transmit a wireless notification indicating that the recommended replacement time has been reached; determining whether a response to the wireless notification is received within a predetermined amount of time from the transmission of the wireless notification; and disabling the behavior modification indicator, the behavior modification indicator comprising a predetermined pacing mode, based on a determination that the response to the transmission of the wireless notification was received within the predetermined amount of time.

[0011] The details of one or more examples of techniques of this disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the techniques of this disclosure will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF DRAWINGS

[0012] FIG. 1 is a conceptual diagram depicting an example system that includes an implantable medical device implanted within a patient and an external user interface device for interacting with the implantable medical device, in accordance with one or more aspects of this disclosure.

[0013] FIG. 2 is a block diagram illustrating an example configuration of the implantable medical device of FIG. 1 in accordance with one or more aspects of this disclosure.

[0014] FIG. 3 is a block diagram illustrating an example configuration of the user interface device of FIG. 1 in accordance with one or more aspects of this disclosure. [0015] FIG. 4 is a flowchart illustrating an example method for determining when to provide an indication of implantable medical device power source depletion, in accordance with one or more aspects of this disclosure. [0016] FIG. 5 is a flowchart illustrating another example method for determining when to provide an indication of implantable medical device power source depletion, in accordance with one or more aspects of this disclosure.

[0017] FIG. 6 is a graph illustrating the output of an example power source and corresponding charge times for charging a capacitor of an implantable medical device equipped with the power source over a depletion history of the power source, in accordance with one or more aspects of this disclosure.

DETAILED DESCRIPTION

[0018] FIG. 1 is a conceptual diagram illustrating a system 8 that includes an implantable medical device (IMD) 14 implanted within a patient 10, in accordance with one or more aspects of this disclosure. As illustrated in FIG. 1, system 8 may also include an external user interface device 16, e.g., a programmer or other computing device, for interacting with the IMD. For purposes of example, IMD 14 is depicted and described throughout this disclosure as an implantable pacemaker, cardioverter-defibrillator, or pacemaker-cardioverter-defibrillator. However, the techniques of this disclosure are not limited to implementation in such devices, or systems including such devices. IMD 14 may include any kind of IMD including a power source, and the techniques described herein with respect to implantable pacemakers, cardioverter-defibrillators, and pacemaker-cardioverter-defibrillators are adaptable to other kinds of IMDs including power sources, as would be readily apparent to a person having ordinary skill in the art. [0019] IMD 14 is powered by a power source 42 (FIG. 2) which has an output that decays as the power source is used. In some examples, power source 42 may have varying decay characteristics as the power source achieves different depths of discharge, e.g., depending on the fraction of the total capacity of the power source discharged. After significant depletion of power source 42, the performance of certain functions by IMD 14, such as delivery of therapy, patient monitoring, or communication, may be impaired. IMD 14 and/or user interface device 16 are configured to monitor the discharge level of power source 42 and/or a level of performance of one or more functions of IMD 14, and provide a warning or other indication to the patient and/or a clinician, e.g., an ERI or RRT indication, so that a surgical procedure to replace IMD 14 may be scheduled and completed in advance of undesired changes in device performance due to, for example, depletion of power source 42. In conventional systems, the threshold power source discharge level or other IMD 14 performance threshold for issuing the ERI or RRT notification is specified by IMD 14 manufacturer and is universal for all patients. Hereinafter, an RRT notification is referred to as an example of a warning or other notification to the patient and/or a clinician so that a surgical procedure to replace IMD 14 may be scheduled and completed in advance of changes in device performance due to, for example, depletion of power source 42, although the techniques described herein are equally applicable to ERI notifications or any such notification.

[0020] In some examples described herein, IMD 14 is a pacemaker. IMD 14 may be configured to switch to a ventricular single chamber pacing (VVI) therapy mode at 65 beats per minute upon occurrence of ERI, to signal that the pacemaker is approaching the end of its service life. A single-chamber pacemaker operates in VVI therapy mode when one lead is positioned in the ventricle; however, the VVI therapy mode can also be programmed in a dual-chamber pacemaker. The VVI therapy mode provides singlechamber inhibited pacing at a programmed pacing rate (e.g., 65 beats per minute), unless inhibited by sensed spontaneous ventricular activity (R-wave). If sensed spontaneous ventricular activity is slower than the programmed pacing rate of the pacemaker, then the pacemaker will pace; otherwise, the pacemaker will not pace.

[0021] VVI therapy mode can be used to provide a signal to a patient that it is time to visit a clinic for a pacemaker replacement. For example, VVI therapy mode at 65 beats per minute (VVI65) may be initiated approximately 90 days prior to ERI and/or RRT. In some pacemakers, 65 beats per minute is reserved for the VVI65 therapy mode and is unavailable for other pacing modes. Since VVI65 therapy mode paces only the ventricle, and not the atrium, in many cases the patient may experience symptoms and realize that the pacemaker needs to be replaced. However, in some situations, the patient may not notice the rate change to 65 bpm. The change to VVI65 therapy mode is least likely to be noticed by patients with AV blocks, and yet these patients may rely on the pacemaker to function normally.

[0022] Although user interface device 16 and/or IMD 14 may be configured to transmit a wireless notification at ERI and/or RRT to alert a clinician, as a practical matter, many IMDs are lost to follow-up and no such notification is received. Likewise, even though some IMDs include external patient monitors that can communicate with IMD 14 to receive radio alerts, many patients lack the requisite technical skills to use these monitors and, thus, the radio alerts will not be received. In situations where pacemaker replacement surgery has already been scheduled, physicians would prefer that the pacemaker remain in programmed pacing mode and not switch over to VVI65 therapy mode, as this mode may result in the patient not receiving normal pacing.

[0023] In some examples described herein, when IMD 14 reaches ERI and/or RRT, IMD 14 transmits a wireless notification. IMD 14 waits for a predetermined amount of time to receive a response to the wireless notification. In some examples, the predetermined amount of time represents a duration of time between RRT and ERI. In a further example, the predetermined amount of time is in a range of approximately 1 month to 6 months. In another example, the predetermined amount of time can be 12 hours to 48 hours after ERI is reached. When a response is received within the predetermined amount of time, IMD 14 does not switch to VVI65 therapy mode. In response to the predetermined amount of time elapsing with no response having been received, IMD 14 switches to VVI65 therapy mode. In a further example, when at least a first amount of time remains prior to end-of-service for IMD 14, a second amount of time less than the first amount of time is provided before ERI is triggered. For example, the first amount of time may be six months and the second amount of time may be three months. Upon occurrence of RRT, IMD 14 transmits a wireless notification which may be received by a monitoring device, sent to a physician, and/or received by a monitoring service. In one example, the receipt of the notification by the clinician and/or the alerting service causes a command to be sent to IMD 14 disabling ERI. In a further example described herein, the receipt of the notification and a review of the notification (e.g., an email being marked as read by a clinician) causes the command to be sent to IMD 14 disabling ERI. In another further example described herein, the receipt and review of the notification, and the scheduling of the surgery to replace IMD 14 causes the command to be sent to IMD 14 disabling ERI. In a still further example described herein, a set of conditions for the command being sent may be programmable.

[0024] IMD 14 may provide electrical stimulation to heart 12 of patient 10, and sense electrical signals within patient, e.g., associated with the depolarization and repolarization of heart 12, via leads 18 and electrodes 20. Leads 18 connect electrodes 20 to IMD 14. Electrodes 20 may be implanted in or proximate to one or more of the left atrium, right atrium 22, right ventricle 24, or left ventricle 26 of heart 12. In some examples, one or more electrodes may be formed integral with the housing of IMD 14. In some examples, an IMD need not be coupled to leads, and may instead rely on one or more electrodes integral to the housing of IMD 14 for electrical sensing and/or stimulation.

[0025] IMD 14 may include one or more communications means, such as a radio antenna, micro-electromechanical system reed switches, or similar devices, to allow a user to interact with IMD 14 through user interface device 16. User interface devicel6 may be a hand held programmer or other computing device configured to communicate with, and in some cases, program IMD 14. User interface device 16 may include a visual display or other means of presenting data transmitted from IMD 14 to a user of user interface device 16. User interface device 16 may also include a means, such as a keypad or touch screen, to allow a user to modify one or more parameters of IMD 14, including selecting an acceptable performance level for IMD 14, as described in greater detail below. In some examples, user interface device 16 may allow the user opportunities to indicate an acceptable performance level of IMD 14 at multiple times, e.g., at implant, at different depths of discharge of the IMD power source, or when a default RRT for IMD 14 is reached.

[0026] FIG. 2 is a block diagram illustrating an example configuration of IMD 14 in accordance with one or more aspects of this disclosure. As illustrated in FIG. 2, IMD 14 may include a processor 28, signal generator 30, sensing module 32, signal analyzer 36, memory 38, telemetry module 40, power source 42, and clock 46. Signal generator 30 and sensing module 32 may be connected to electrodes 20, e.g., via leads 18. Signal generator 30 may include one or more discharge capacitors 44, e.g., for delivery of therapeutic signal, such as pacing, cardioversion or defibrillation pulses, via electrodes 20. Processor 28 may receive data regarding the performance of power source 42 and/or IMD 14 via one or more sensors, such as a charge sensor 48 monitoring the performance of discharge capacitor 44, or power sensor 50 monitoring one or more parameters of power source 42. IMD 14 may communicate with user interface device 16 via telemetry module 40.

[0027] Processor 28 may be programmed or otherwise configured to control the operation of IMD 14. In some examples, processor 28 may perform or control the functions ascribed to IMD 14 or various modules of IMD 14 herein, including initiating one or more wireless notifications as described in the context of FIG. 1, using software instructions stored in memory 38. Processor 28 may include one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or any other equivalent integrated or discrete logic circuitry, as well as any combinations of such components.

[0028] Sensing module 32 may receive electrical signals representative of cardiac activity via various combinations of two or more electrodes 20, i.e., via various sensing vectors. Through the various sensing vectors, sensing module 32 may receive signals representative of electrical activity of various regions of heart 12 of patient 10, allowing IMD 14 to detect the progression of electrical signals through heart 12. In some examples, sensing module 32 includes circuitry configured to detect and provide indications of the occurrence of specific cardiac events, such as depolarizations, e.g., R-waves and P-waves, based on the signals.

[0029] Signal analyzer 36 may receive the electrical signals of heart 12 or other data gathered by sensing module 32, e.g., indications of depolarizations or other cardiac events, and interpret the information to, for example, guide the therapy administered by IMD 14. For example, signal analyzer 36 may identify bradycardia or a tachyarrhythmia based on the data, and processor 28 may responsively control signal generator 30 to deliver one or more therapeutic electrical signals to heart 12 via electrodes 20 in response to the identification. As described above, the delivery of such therapeutic signals may involve charging and discharging of discharge capacitors 44. In various examples, signal analyzer 36 may be embodied as a discrete hardware component of IMD 14, a set of software instructions contained in memory 38 and executed by processor 28, or some combination thereof. Signal analyzer 36 may store the data representative of cardiac activity in memory 38, e.g., for analysis by processor 28 and/or transmission to an external device through telemetry module 40.

[0030] Memory 38 may include any volatile or non-volatile media, such as a random access memory (RAM), read only memory (ROM), non-volatile RAM (NVRAM), electrically erasable programmable ROM (EEPROM), flash memory, and the like. Memory 38 may contain instructions that, when executed by processor 28 or other modules of IMD 14, control the operation of IMD 14. The contents of memory 38 may be updated through instructions received via telemetry module 40, e.g., from user interface device 16. Memory 38 may also store data gathered by sensing module 32, signal analyzer 36 and onboard sensors, such as power sensor 50, and charge sensor 48. Data from these sensors may be transmitted to user interface device 16 via telemetry module 40. [0031] Telemetry module 40 may include circuitry for transmitting data indicating the status of IMD 14 and, in some examples, the status or recorded medical history of patient 10 to user interface device 16, as well as receiving instructions or other data from the user interface device. Telemetry module 40 may comprise one or more of a radio transceiver for radio frequency communication, a proximal inductive transceiver, a cellular communications device, magnetic communication device, or a Bluetooth or other peer-to- peer communications mechanism, as examples. In some examples, telemetry module 40 may include multiple communications means, allowing IMD 14 to communicate with a range of devices, or at a range of distances or bandwidths, depending on the situation. Telemetry module 40 may establish a communication with user interface device 16 while patient 10 is in the presence of the clinician or other user of user interface device 16. When patient 10 is at home or elsewhere, telemetry module 40 may update a clinician of cardiac or other events via a cellular, telephonic, or internet network, e.g., via an external interface device (not shown) that is equipped to communicate both with telemetry module 40 and such networks.

[0032] Power source 42 may include a battery, capacitor, and/or other energy storage device that stores energy and provides electrical power to IMD 14. As IMD 14 consumes the electrical power supplied by power source 42, the output, e.g., voltage and/or current, provided by power source 42 may decay. Power source 42 may be configured to provide an extended period of relatively constant output until power source 42 nears a designed end of service, marked by a more rapid decline in output. This may occur as, for example, the chemicals composing power source 42 are expended in a chemical reaction generating the electrical output. Some examples of power source 42 may include multiple electrochemical reactions, creating a hybrid power output defined by two or more periods of relatively constant output interspersed with more rapid decreases in electricity generated.

[0033] Clock 46 may be configured to synchronize the functions of IMD 14. Clock 46 may also, in some examples provide a time basis for a measure or estimate of the historical power consumption by IMD 14 of patient 10, and for providing an RRT notification, by processor 28. The rate of power consumption by IMD 14 may vary from patient-to-patient depending on, for example, the seriousness of the symptoms of the patient, and thus the amount of monitoring or therapy provided to the patient. In some examples, processor 28 may determine the RRT and provide an RRT notification based on the measured or estimated consumption of power source 42 over time.

[0034] Discharge capacitors 44 may include capacitors configured to provide relatively high voltage therapy (relative to cardiac pacing), such as cardioversion and defibrillation therapy, to patient 10. Such high voltage capacitors may have relatively higher voltage capacity. Furthermore, the time required for power source 42 to charge such capacitors to a level sufficient for such higher voltage therapies may be relatively longer than the time required to charge capacitors for delivery of pacing pulses. As power source 42 is depleted, the time required to charge the high capacity capacitors may measurably increase.

[0035] Charge sensor 48 may be configured to facilitate measurement of the capacity of power source 42 based on the time required to charge discharge capacitors 44 to a predetermined level. Discharge capacitor 44 may be charged to a known level, e.g., a therapeutic or sub-therapeutic level, which may occur during delivery of therapy, or when the capacitors will be discharged without delivery of therapy to heart 12. Charge sensor 48 may measure the charge in discharge capacitors 44. Processor 28 may compare the charge measured by charge sensor 48 to a threshold, e.g., associated with a therapeutic or sub-therapeutic level, and also may determine the time to reach the threshold charge using the output of clock 46. The charge time may indicate the output available from power source 42, with longer charge times showing a greater depletion, e.g., depth of discharge, of the power source.

[0036] In some examples, processor 28 may control periodic testing of the depth of discharge of power source 42 by charging and discharging, e.g., without delivery of therapy to heart 12, one or more of discharge capacitors 44, and measuring the time to reach the predetermined level of charge, as described above. In such examples, the level to which the capacitors are charged may be less than required for therapy, i.e., sub- therapeutic, and may be a fraction of a therapeutic level or a full charge. By charging discharge capacitors 44 to a lower level in this manner, the energy consumption of the periodic test may be reduced. Charge sensor 48 may include a voltage meter, coulomb meter, or other sensor, that measures an electrical characteristic of the charge of discharge capacitors 44. For example, charge sensor 48 may measure the voltage or current drop across discharge capacitors 44, or a resistor connected to the capacitor.

[0037] Power sensor 50 may be integrated with, or connected to, power source 42. Power sensor 50 may measure the depletion of power source 42 by measuring the voltage or current output, impedance, or charge remaining of power source 42, and provide the measurement to processor 28. In some examples, power sensor 50 or processor 28 may determine the remaining charge of power source 42 by implementing a coulomb counter to determine or estimate the charge depleted from power source over time based on one or more of the voltage or current output of power source 42 measured by power sensor 50 and the output of clock 46. In some examples, processor 28 may determine RRT and/or ERI based on the measured depletion of power source 42.

[0038] Processor 28 may use the measure of the decay of power source 42 to determine a course of action, such as notifying the patient or some other user, e.g., via user interface device 16 or another networked computer, that the RRT of power source 42 has been reached and that replacement of IMD 14 may be scheduled. A safety margin may be incorporated into the threshold depth of discharge or other triggering factor for replacement of power source 42, providing time to make arrangements to have power source 42 replaced before the performance of IMD 14 appreciably degrades.

[0039] User interface device 16 may be a remote programming device or other computing device configured to interact with IMD 14. User interface device 16 may display output from one or more sensors or sensing module 32 of IMD 14 stored in memory 38. Telemetry module 40 may transmit the data to user interface device 16. User interface device 16 may also allow a user to adjust the operating parameters of IMD 14, and provide options allowing the user to accept or select a reduced performance of IMD 14 prior to or following a first threshold of depth of decay of power source 42 in exchange for extended usable life of power source 42. User selections and updated operating code may be downloaded from user interface device 16 to IMD 14 via telemetry module 40 and stored in memory 38.

[0040] FIG. 3 is a block diagram illustrating an example configuration of user interface device 16 of FIG. 1 in accordance with one or more aspects of this disclosure. As illustrated in FIG. 3, user interface device 16 may include processor 52, memory 54, telemetry module 56, and user interface 58. In general, user interface device 16 may take the form of any type of computing device, such as a handheld, tablet, or desktop computing device.

[0041] Processor 52 may receive data regarding the performance of power source 42 or other components of IMD 14 (FIG. 2) from IMD 14, e.g., via telemetry module 40 of IMD 14 (FIG. 2) and telemetry module 56. The data may be generated by one or more sensors, such as a charge sensor 48 or power sensor 50 of IMD 14 (FIG. 2), for example. Processor 52 of user interface device 16 may display such data regarding the performance of power source 42 to patient 10, a clinician, or another user, and may receive commands or other input from the user, via user interface 58. Processor 52 may store the input in memory 54, and transmit one or more parameters or commands responsive to the user input to IMD 14 via telemetry module 56.

[0042] Processor 52 may be programmed or otherwise configured to control the operation of user interface device 16. In some examples, processor 52 may perform or control the functions ascribed to user interface device 16 or various modules of user interface device 16 herein using software instructions stored in memory 54. Processor 52 may include one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or any other equivalent integrated or discrete logic circuitry, as well as any combinations of such components.

[0043] Memory 54 may include any volatile or non-volatile media, such as a random access memory (RAM), read only memory (ROM), non-volatile RAM (NVRAM), electrically erasable programmable ROM (EEPROM), flash memory, and the like. Memory 54 may contain instructions that, when executed by processor 52 or other modules of user interface device 16, control the operation of user interface device 16 and, in some examples, IMD 14. The contents of memory 54 may be updated through instructions received via user interface, 58. Memory 54 may also store data gathered by sensing module 32, signal analyzer 36 and onboard sensors, such as power sensor 50, and charge sensor 48 of IMD 14, which may be received by user interface device 16 from IMD 14 via telemetry module 56.

[0044] Telemetry module 56 may include one or more means of receiving data indicating the status of IMD 14 and, in some examples, transmitting instructions or other data to IMD 14. Telemetry module 56 may comprise one or more of a radio transceiver radio frequency communication, a proximal inductive transceiver, a cellular communications device, magnetic communication device, or a Bluetooth or other peer-to- peer communications mechanism, as examples. In some examples, telemetry module 56 may include multiple communications means, allowing telemetry module 56 to communicate with a range of devices, or at a range of distances or bandwidths, depending on the situation. Telemetry module 56 may establish a communication with IMD 14 while patient 10 is in the presence of the clinician or other user of user interface device 16. When patient 10 is at home or elsewhere, telemetry module 56 may receive updates of cardiac or other events from IMD 14, e.g., via a cellular, telephonic, or internet network. [0045] User interface 58 may be configured to allow patient 10 or a clinician to receive data from IMD 14 and input parameters and/or commands to be transmitted to IMD 14. User interface 58 may include elements for visual and, in some examples, audio output, e.g., a display and speakers. User interface 58 may receive tactile input, e.g., via a touch sensitive screen, keyboard, mouse or other pointing device, or any similar devices. Processor 52 may store detected inputs in memory 54 and format the inputs into transmission, by telemetry module 56, to IMD 14.

[0046] FIG. 4 is a flowchart illustrating an example method for determining when to provide an indication of implantable medical device power source depletion, in accordance with one or more aspects of this disclosure. The example methods, and any part thereof, may be performed by any one or more of the devices described herein, such as IMD 14 (FIGs. 1-2), user interface device 16 (FIGs. 1-3), processor 28 (FIG. 2), or processor 52 (FIG. 3). For example, the methods described herein may be generally performed by IMD 14, with IMD 14 communicating with the user via user interface device 16. In other examples, user interface device 16 may receive various data from IMD 14, determine, receive, and/or store an RRT, and configure IMD 14 accordingly.

[0047] According to the example method of FIG. 4, IMD 14 (FIG. 1) stores an RRT for the IMD, and/or an activation time of an ERI for the IMD, in memory 38 (FIG. 2) of the IMD (FIG. 4, block 402). The RRT and/or the ERI may be based on a target or acceptable level of performance for IMD 14 (FIG. 1) with respect to at least one performance characteristic of IMD 14. At block 404 (FIG. 4), IMD 14 (FIG. 1) determines whether or not the RRT and/or the activation time of the ERI is reached. When the RRT and/or the activation time of the ERI has not been reached, the program loops back to block 404 (FIG. 4). When the RRT and/or the activation time of the ERI has been reached, the program progresses to block 406 where IMD 14 (FIG. 1) transmits a wireless notification indicating that the RRT and/or the activation time of the ERI has been reached.

[0048] At block 408 (FIG. 4), a test is performed by IMD 14 (FIG. 1) to ascertain whether or not a response to the wireless notification has been received by the IMD within a predetermined amount of time. In some examples, the predetermined amount of time represents a duration of time between the RRT and the activation time of the ERI. In a further example, the predetermined amount of time is in a range of approximately 1 month to 6 months. In another example, the predetermined amount of time can be 12 hours to 48 hours after ERI is reached. When a response is not received within the predetermined amount of time, IMD 14 switches to a VVI therapy mode, such as a VVI65 therapy mode, at block 410 (FIG. 4). When a response is received within the predetermined amount of time at block 408, IMD 14 (FIG. 1) does not switch to the VVI therapy mode (FIG. 4, block 412).

[0049] In some examples, user interface device 16 may display a prompt or other notification to a user of IMD 14 indicating that IMD has transmitted the wireless notification at block 406 (FIG. 4). In some examples, user interface device 16 may display a prompt or other notification to the user of IMD 14 indicating that IMD 14 has received a response to the wireless notification within the predetermined amount of time at block 408 (FIG. 4). In some examples, IMD 14 determines the value for the RRT and/or the activation time of the ERI that is stored at block 402 (FIG. 4) based on one or more performance characteristics of IMD 14. These performance characteristics may include, but are not limited to, charge time of discharge capacitors 44 (FIG. 2), voltage output of power source 42, pacing rate of IMD 14, pacing intensity (e.g., the voltage or current of a pacing pulse) of IMD 14, amount charge remaining in power source 42, or similar metrics. Based on the one or more performance characteristics, processor 28 of IMD 14 may be able to determine when the determined RRT and/or the determined activation time for the ERI has been reached, allowing IMD 14 to notify patient 10 (FIG. 1) or some other user (e.g., a clinician) that replacement of IMD 14 is required.

[0050] Input of a target, adequate, or acceptable level of performance may be performed at implantation of IMD 14, or later during the operation of IMD 14. A later time of selection may allow patient 10 and a clinician to observe how patient 10 responds to IMD 14. If a patient tolerates IMD 14 well, patient 10 or the clinician may elect to lower the acceptable performance guidelines, extending the life of power source 42. Indications that the load on IMD 14 is more severe than predicted, e.g., more frequent energy demands resulting in faster drain, may lead patient 10 or the clinician to require higher standards of performance. Selection of an acceptable level of performance made after implantation may be communicated to IMD 14 via telemetry module 40, either over a radio connection, such as Bluetooth or a similar protocol, or through magnetic interaction between IMD 14 and user interface device 16. The acceptable level of performance of IMD 14 and other operating parameters may be stored in memory 38, accessible to processor 28.

[0051] Processor 28 of IMD 14 may determine RRT by monitoring one or more performance characteristics through sensors included in IMD 14, such as charge sensor 48 (FIG. 2) and power sensor 50. Based on the output of the included sensors, processor 28 (or user interface device 16) may determine when power source 42 and IMD 14 will no longer meet the acceptable level of performance. In some examples, processor 28 may record a history of the performance level of power source 42 and IMD 14, based on measurements by the included sensors and clock 46, allowing processor 28 to be configured to predict RRT for power source 42. Processor 28 may still monitor the performance level of power source 42 and IMD 14, as usage and needs may change, but the predicted RRT may be indicated to patient 10 or other user to allow advanced planning for the replacement of power source 42.

[0052] In calculating RRT, processor 42 may factor in an acceptable safety margin, allowing a window for the scheduling of the replacement of power source 42 without the performance of IMD 14 degrading sufficiently to threaten the health of patient 10. The safety margins of IMD 14 may also be adjustable. If IMD 14 maintains a history of power consumption by IMD 14 and patient 10, IMD 14 may be configured to base the safety margin on the historical energy consumption of patient 10, rather than relying on the average or worst case scenario of a theoretical patient. Also, by predicting RRT, the safety margin may be narrowed as the general range of when RRT will fall may be known in advance, allowing earlier scheduling and minimizing conflicts with the daily activities of patient 10. In some instances, the usage history of IMD 14 or the general health of patient 10 may indicate that IMD 14 is a minor factor in the overall well-being of patient 10 and that basing the safety margin on an optimistic prediction of future use will not put patient 10 at risk, allowing the life of power source 42 and RRT to be extended.

[0053] At block 404 (FIG. 4), processor 28 (FIG. 2) may monitor one or more performance characteristics through sensors included in IMD 14, such as charge sensor 48 and/or power sensor 50, to determine that RRT is reached based on one or more performance characteristics falling below a target, acceptable, or adequate level, and/or when clock 46 registers crossing a time threshold. The time threshold may indicate a predicated time when the performance of IMD 14 may fall below an acceptable, adequate, or target level and may be predicted based on historical use of IMD 14 by patient 10, other patients, or a theoretical patient as discussed previously. Processor 28 may transmit an indication, e.g., via user interface device 16, to patient 10 or a clinician that RRT has been reached and request scheduling replacement of power source 42 or a new set of acceptable performance levels to recalculate RRT.

[0054] Processor 28 of IMD 14, via telemetry module 40, may indicate that RRT has been reached when the performance characteristic of the implantable medical device no longer meets or exceeds the acceptable, adequate, or target level of performance. The indication that RRT of power source 42 is reached may take the form of a message or other warning displayed via user interface device 16. In some examples, IMD 14 may alert patient 10 or a clinician of RRT in an email or other message sent to patient 10 or the clinician directly from IMD 14. The indication that RRT has been reached may also include a prompting to a user of IMD 14 to select another acceptable level of performance if postponing the replacement of power source 42, while reducing performance, is acceptable.

[0055] FIG. 5 is a flowchart illustrating another example method for determining when to provide an indication of implantable medical device power source depletion, in accordance with one or more aspects of this disclosure. At block 500, the method may include storing a value for an RRT and/or an activation time of an ERI of IMD 14 (FIG. 1) in memory 38 (FIG. 2) based on a target, adequate, or acceptable level of performance for IMD 14 (FIGs. 1 and 2). The target, adequate, or acceptable level of performance may be determined with respect to at least one performance characteristic of IMD 14, as described previously in connection with FIG. 4. [0056] At block 502 (FIG. 5), IMD 14 (FIG. 1) determines that a remaining amount of time exists prior to an end of service life for IMD 14. For example, the end of service life may represent a time at which IMD 14 no longer functions due to power source depletion. IMD 14 determines a second amount of time less than the remaining amount of time for activating the ERI (FIG. 5, block 504). At block 506, IMD 14 (FIG. 1) performs a test to ascertain whether or not the second amount of time has expired. For example, processor 28 (FIG. 2) may determine that the second amount of time has expired by monitoring clock 46. When the second amount of time has expired, IMD 14 (FIG. 1) initiates a VVI therapy mode (FIG. 5, block 516), such as a VVI65 therapy mode. When the second amount of time has not expired, the program advances to block 508 where a test is performed to ascertain whether or not the RRT for the IMD has been reached. If not, the program loops back to block 506 (described previously). The affirmative branch from block 508 leads to block 510 where IMD 14 (FIG. 1) transmits a wireless notification indicating that the RRT has been reached. For example, the wireless notification may be transmitted by user interface device 16 (FIG. 2) of IMD 14. IMD 14 receives a command to disable the ERI for the IMD (FIG. 5, block 512). For example, the command may be received by user interface 16 (FIG. 2) from a medical care provider computing system, an email server, a Bluetooth transceiver, a mobile device, or any of various combinations thereof. In response to the command, IMD 14 disables the ERI and does not initiate VVI65 therapy mode.

[0057] In a further example described herein, user interface 16 prompts a user to select an acceptable performance level by displaying a message or some other cue via user interface device 16. A device supporting user interface device 16 may also give patient 10, the clinician, or some other user an audible message, such as a recorded voice message, instructing the user to input an acceptable performance level. The prompt may be delivered before, during, or after implantation of IMD 14. In some examples, the user may be prompted to input or select an acceptable performance level multiple times during the life span of power source 42. This may allow RRT of power source 42 to be adjusted as conditions and the health of patient 10 warrant. IMD 14 may trigger the prompting of the user to input or select an acceptable performance level by transmitting a command, via telemetry module 40, to the device supporting user interface device 16. IMD 14 may trigger the prompt based on a range of factors related to the depth of discharge of power source 42, including measured charge levels, impedance, or voltage output, other factors include duration of use, capacitor charge times, and patient symptoms.

[0058] In a further example described herein, block 508 (FIG. 5) is performed by accepting a user input to IMD 14 indicating an acceptable level of performance of IMD 14 with respect to at least one performance characteristic of IMD 14 may include receiving the acceptable level of performance from a device supporting user interface device 16 with a module, e.g., telemetry module 40, of IMD 14 and storing the parameter in memory 38. Once accepted, processor 28 may compare the measurements made by one or more sensors, such as charge sensor 48 or power sensor 50, to the parameter, allowing processor 28 to determine if RRT for power source 42 has been reached.

[0059] Processor 28 may determine that the RRT for power source 42 is reached as a function of the user indicated level of performance. If IMD 14 is no longer able to provide satisfactory performance due to power shortages caused by the decay of power source 42, it is likely necessary to replace power source 42. Determination that the RRT has been reached may be made when, for example, one or more capacitors of IMD 14 are no longer able to charge within a given time threshold, when power source 42 output voltage or charge falls below a set threshold, when the impedance of power source 42 rises above a threshold, usage time and history indicates replacement is warranted, and similar factors. Upon entry and acceptance of a new acceptable level of performance for IMD 14, processor 28 may extend the operation of IMD 14, until a new RRT for power source 42 based on the new parameter is reached, as determined by processor 28. Further, processor 28 may predict when RRT has been reached based on past usage history of patient 10 or example patients, either average or worst case. By predicting RRT, IMD 14 may enable a clinician, patient 10, or other user to adjust the acceptable level of performance to achieve a desired recommended replacement time.

[0060] IMD 14 may indicate that RRT has been reached when the performance characteristic of the implantable medical device no longer meets or exceeds the user indicated acceptable level of performance. At block 510 (FIG. 5), IMD 14, at the command of processor 28 and through telemetry module 40, may transmit a message indicating that the RRT of power source 42 has been reached or will imminently do so. The message may include a prompting for a user to input or select a new acceptable level of performance to allow IMD 14 to extend operations without the immediate replacement of power source 42. The message may be received by a device supporting user interface device 16 and displayed to the user via user interface device 16. IMD 14 may also give some other indication, such as an audible or vibrational alert, to inform patient 10 of the need to replace power source 42 shortly.

[0061] In a further example described herein, IMD 14 may deactivate a non-essential feature of IMD 14 to extend the life of power source 42. IMD 14 may include features that are not required to provide adequate therapy to patient 10. For example, wireless transceivers built into telemetry module 10 may consume significant amounts of power. While beneficial in allowing a clinician to remotely diagnosis a cardiac event, wireless communication may be redundant with a magnetic-based communication included with IMD 14, provided patient 10 is able to access a machine capable of magnetically communicating with IMD 14. By deactivating the wireless transceiver in telemetry module 40, IMD 14 may reduce power consumption and extend the life of power source 42. Similarly, processor 28 might deactivate sensing module 32 and signal analyzer 36 for certain periods of constant heart rate, e.g., during non-REM sleep stages, allowing IMD 14 to revert to constant rather than reactive pacing. Processor 28 may reactivate non-essential modules or components of IMD 14 temporarily. In one example, processor 28 may reactivate sensing module 32 and signal analyzer 36 for the REM portion of the sleep cycle of patient 10, allowing IMD 14 to match the variable heart portion of the sleep cycle patient 10 and allow patient 10 to sleep more easily while still reducing power consumption overall by reducing functionality when not needed.

[0062] FIG. 6 is a graph illustrating the output of an example power source and corresponding discharge capacitor charge times for IMD 14 (FIG. 2) equipped with power source 28. Curve 60 (FIG. 6) represents the charging time of discharge capacitors 44 (FIG. 2) of IMD 14. Curve 62 (FIG. 6) represents the voltage output of power source 42 (FIG. 2) of IMD 14. The x-axis of FIG. 6 displays depth of discharge (DOD), the fraction of the energy of power source 42 (FIG. 2) consumed, and represents the life span of the power source elapsed since the installation of the power source in the implantable medical device.

[0063] Implantation of IMD 14 occurs at DOD mark 64 (FIG. 6). Power source 42 (FIG. 2) of IMD 14 may be discharged slightly before implanting due to leakage and decay during storage as well as various preparatory activities, such as programming the implantable medical device, required before implantation. At implantation, the power source may provide an output of approximately 3.1 to 3.2 volts and allow the discharge capacitor to charge in approximately 10 seconds. Immediately following implantation the power source experiences an abrupt but relatively small decline in potential output followed by an extended period of relatively constant output capacity with only a gradual decline. This corresponds with gradual increase in charge times of the discharge capacitor. [0064] As the DOD (FIG. 6) approaches 60 to 70 percent, the rate of decay of power source 42 (FIG. 2) increases. In a typical power source 42, the increase in the rate of decay of the power source may be expected to continue until power source 42 is completely discharged. The electrochemistry of power source 42 may be adjusted to alter the trajectory of the decay of the power source, attempting to maintain the highest output for as long as possible, followed by an abrupt failure or to maintain a more moderate output with a moderate decay rate. The transition into increased rates of decay may mark am RRT, set, for example, by a threshold DOD that leaves sufficient performance in power source 42 to safely operate IMD 14 for a period of time to allow patient 10 (FIG. 1) using IMD 14 (FIGs. 1 and 2) to get power source 42 (FIG. 2) replaced. Accompanying the decrease in available output capacity of power source 42 is a large increase in the charging time for discharge capacitors 44.

[0065] Between DOD mark 66 and DOD mark 68 (FIG. 6), the acceleration of the decay of power source 42 (FIG. 2) decreases. This occurs when power source 42 is a hybrid, a power source formed by including multiple electrochemical reactions that provide a plurality of temporary regions of stable output, albeit at a reduced levels, near the complete discharge of power source 42. This second region of stable output may allow the usable life of power source 42 to be significantly extended, provided the patient is able tolerate the reduced performance of IMD 14. Curve 60 (FIG. 6) shows the increase in charging time, rising from 10 to 15 or more seconds, that occurs because of the reduced capacity of power source 42 (FIG. 2). The rate of increase of the charge time shown by curve 60 (FIG. 6) slows as the DOD of curve 62 levels. By enabling the user of IMD 14 to choose the acceptable level of performance of IMD 14, patient 10 (FIG. 1) may increase the life span of power source 42 (FIG. 2) and delay replacement.

[0066] DOD mark 68 (FIG. 6) shows the resumption of the accelerating decay of power source 42 (FIG. 2). At this point, there is some safety margin to allow for the replacement of power source 42. In some examples, depending on the health of patient 10 (FIG. 1) and the usage history of IMD 14, the safety margin may be adjusted to further delay the replacement of power source 42 (FIG. 2). The safety margin may be adjusted based on user input after evaluation occurring before or at either of two RRTs at DOD mark 66 and 58 (FIG. 6). Following the replacement of power source 42 (FIG. 2), a fresh cycle of discharge and monitoring using the new power source may begin again from DOD mark 64 (FIG. 6).

[0067] Various examples have been described. These and other examples are within the scope of the disclosure.

[0068] Example 1. An implantable medical device comprising: processing circuitry, and memory operatively coupled to the processing circuitry; wherein the processing circuitry is configured to: store a recommended replacement time and an activation time of a behavior modification indicator for the implantable medical device in the memory, based on a target level of performance for at least one performance characteristic of the implantable medical device; determine that the recommended replacement time has been reached; control telemetry circuitry to transmit a wireless notification indicating that the recommended replacement time has been reached; determine whether a response to the wireless notification is received within a predetermined amount of time from the transmission of the wireless notification; and based on a determination that the response to the transmission of the wireless notification was received within the predetermined amount of time, disabling the behavior modification indicator, the behavior modification indicator comprising a predetermined pacing mode or pacing parameter.

[0069] Example 2. The implantable medical device of Example 1, wherein the implantable medical device includes one or more power sources, and wherein the at least one performance characteristic of the implantable medical device changes as the one or more power sources is consumed over time.

[0070] Example 3. The implantable medical device of any of Examples 1-2, wherein the received response to the wireless notification comprises a command instructing the processing circuitry to disable or prevent some or all of a recommended set of behavior modifications for the behavior modification indicator.

[0071] Example 4. The implantable medical device of Example 1, wherein the received response to the wireless notification is indicative of at least one of the wireless notification having been received by another device, the wireless notification having been viewed by a clinician, or a replacement surgery having been scheduled for replacement of the implantable medical device.

[0072] Example 5. The implantable medical device of any of Examples 1-4, wherein the at least one performance characteristic comprises a maximum acceptable charging time of a discharge capacitor of the implantable medical device.

[0073] Example 6. The implantable medical device of any of Examples 2-5, wherein the processing circuitry is further configured to deactivate one or more non-essential features of the implantable medical device after the at least one performance characteristic of the implantable medical device indicates that the one or more power sources have reached the recommended replacement time.

[0074] Example 7. The implantable medical device of Example 6, wherein the processing circuitry is further configured to deactivate or cause to act in a reduced current drain mode, a wireless radio telemetry capability of the implantable medical device after the at least one performance characteristic of the implantable medical device indicates that the one or more power sources have reached the recommended replacement time.

[0075] Example 8. A method comprising: storing a recommended replacement time and an activation time of a behavior modification indicator for an implantable medical device in a non-transitory, computer-readable memory, based on a target level of performance for at least one performance characteristic of the implantable medical device; determining that the recommended replacement time has been reached; controlling telemetry circuitry to transmit a wireless notification indicating that the recommended replacement time has been reached; determining whether a response to the wireless notification is received within a predetermined amount of time from the transmission of the wireless notification; and disabling the behavior modification indicator, the behavior modification indicator comprising a predetermined pacing mode, based on a determination that the response to the transmission of the wireless notification was received within the predetermined amount of time.

[0076] Example 9. The method of Example 8, wherein the implantable medical device includes one or more power sources, the method further comprising monitoring the at least one performance characteristic of the implantable medical device as the one or more power sources are consumed over time. [0077] Example 10. The method of Example 8 or Example 9, further comprising: determining a remaining amount of time for the implantable medical device prior to an end-of-service for the implantable medical device; determining the recommended replacement time based on the remaining amount of time; determining a second amount of time less than the remaining amount of time; and triggering an activation of the behavior modification indicator based on the second amount of time.

[0078] Example 11. The method of any of Examples 8-10, further comprising transmitting the wireless notification in response to an occurrence of the recommended replacement time.

[0079] Example 12. The method of any of Examples 8-11, wherein the received response to the wireless notification comprises a command for disabling the behavior modification indicator.

[0080] Example 13. The method of Example 12, wherein the received response to the wireless notification is indicative of at least one of the wireless notification having been received by another device, the wireless notification having been viewed by a clinician, or a replacement surgery having been scheduled for replacement of the implantable medical device.

[0081] Example 14. The method of any of Examples 8-13, wherein the at least one performance characteristic comprises a maximum acceptable charging time of a discharge capacitor of the implantable medical device.

[0082] Example 15. The method of any of Examples 9-14, further comprising deactivating a non-essential feature of the implantable medical device after the at least one performance characteristic of the implantable medical device indicates that the one or more power sources have reached the recommended replacement time.

[0083] Example 16. The method of Example 15, further comprising deactivating a wireless radio telemetry capability of the implantable medical device after the at least one performance characteristic of the implantable medical device indicates that the one or more power sources have reached the recommended replacement time.

[0084] Example 17. A computer-readable medium encoded with instructions that if executed by one or more programmable processors of an implantable medical device cause the implantable medical device to perform operations comprising: storing, in the computer-readable medium, a recommended replacement time and an activation time of a behavior modification indicator for the implantable medical device, based on a target level of performance for at least one performance characteristic of the implantable medical device; determining that the recommended replacement time has been reached; controlling telemetry circuitry to transmit a wireless notification indicating that the recommended replacement time has been reached; determining whether a response to the wireless notification is received within a predetermined amount of time from the transmission of the wireless notification; and disabling the behavior modification indicator, the behavior modification indicator comprising a predetermined pacing mode, based on a determination that the response to the transmission of the wireless notification was received within the predetermined amount of time.

[0085] Example 18. The computer-readable medium of Example 17, wherein the implantable medical device includes one or more power sources, and the computer- readable medium further comprises instructions for monitoring the at least one performance characteristic of the implantable medical device as the one or more power sources are consumed over time.

Claims

CLAIMS:

1. An implantable medical device comprising: processing circuitry, and memory operatively coupled to the processing circuitry; wherein the processing circuitry is configured to: store a recommended replacement time and an activation time of a behavior modification indicator for the implantable medical device in the memory, based on a target level of performance for at least one performance characteristic of the implantable medical device; determine that the recommended replacement time has been reached; control telemetry circuitry to transmit a wireless notification indicating that the recommended replacement time has been reached; determine whether a response to the wireless notification is received within a predetermined amount of time from the transmission of the wireless notification; and based on a determination that the response to the transmission of the wireless notification was received within the predetermined amount of time, disabling the behavior modification indicator, the behavior modification indicator comprising a predetermined pacing mode or pacing parameter.

2. The implantable medical device of claim 1, wherein the implantable medical device includes one or more power sources, and wherein the at least one performance characteristic of the implantable medical device changes as the one or more power sources is consumed over time.

3. The implantable medical device of any of claims 1-2, wherein the received response to the wireless notification comprises a command instructing the processing circuitry to disable or prevent some or all of a recommended set of behavior modifications for the behavior modification indicator.

4. The implantable medical device of claim 1, wherein the received response to the wireless notification is indicative of at least one of the wireless notification having been received by another device, the wireless notification having been viewed by a clinician, or a replacement surgery having been scheduled for replacement of the implantable medical device.

5. The implantable medical device of any of claims 1-4, wherein the at least one performance characteristic comprises a maximum acceptable charging time of a discharge capacitor of the implantable medical device.

6. The implantable medical device of any of claims 2-5, wherein the processing circuitry is further configured to deactivate one or more non-essential features of the implantable medical device after the at least one performance characteristic of the implantable medical device indicates that the one or more power sources have reached the recommended replacement time.

7. The implantable medical device of claim 6, wherein the processing circuitry is further configured to deactivate or cause to act in a reduced current drain mode, a wireless radio telemetry capability of the implantable medical device after the at least one performance characteristic of the implantable medical device indicates that the one or more power sources have reached the recommended replacement time.

8. A method comprising: storing a recommended replacement time and an activation time of a behavior modification indicator for an implantable medical device in a non-transitory, computer- readable memory, based on a target level of performance for at least one performance characteristic of the implantable medical device; determining that the recommended replacement time has been reached; controlling telemetry circuitry to transmit a wireless notification indicating that the recommended replacement time has been reached; determining whether a response to the wireless notification is received within a predetermined amount of time from the transmission of the wireless notification; and disabling the behavior modification indicator, the behavior modification indicator comprising a predetermined pacing mode, based on a determination that the response to the transmission of the wireless notification was received within the predetermined amount of time.

9. The method of claim 8, wherein the implantable medical device includes one or more power sources, the method further comprising monitoring the at least one performance characteristic of the implantable medical device as the one or more power sources are consumed over time.

10. The method of claim 8 or claim 9, further comprising: determining a remaining amount of time for the implantable medical device prior to an end-of-service for the implantable medical device; determining the recommended replacement time based on the remaining amount of time; determining a second amount of time less than the remaining amount of time; and triggering an activation of the behavior modification indicator based on the second amount of time.

11. The method of any of claims 8-10, further comprising transmitting the wireless notification in response to an occurrence of the recommended replacement time.

12. The method of any of claims 8-11, wherein the received response to the wireless notification comprises a command for disabling the behavior modification indicator.

13. The method of claim 12, wherein the received response to the wireless notification is indicative of at least one of the wireless notification having been received by another device, the wireless notification having been viewed by a clinician, or a replacement surgery having been scheduled for replacement of the implantable medical device.

14. The method of any of claims 8-13, wherein the at least one performance characteristic comprises a maximum acceptable charging time of a discharge capacitor of the implantable medical device.

15. A computer-readable medium encoded with instructions that if executed by one or more programmable processors of an implantable medical device cause the implantable medical device to perform operations comprising: storing, in the computer-readable medium, a recommended replacement time and an activation time of a behavior modification indicator for the implantable medical device, based on a target level of performance for at least one performance characteristic of the implantable medical device; determining that the recommended replacement time has been reached; controlling telemetry circuitry to transmit a wireless notification indicating that the recommended replacement time has been reached; determining whether a response to the wireless notification is received within a predetermined amount of time from the transmission of the wireless notification; and disabling the behavior modification indicator, the behavior modification indicator comprising a predetermined pacing mode, based on a determination that the response to the transmission of the wireless notification was received within the predetermined amount of time.