Power supply life

Abstract

In some examples, determining an estimated remaining life of a power supply for an implantable medical device includes: determining values of one or more parameters of the power supply and one or more operating parameters of the implantable medical device; calculating a first estimated duration of time until one of the determined parameters of the power supply reaches a pre-recommended replacement time (pre-RRT) threshold based on at least some of the determined parameter values, and adding a timer duration to determine the first estimated life value; calculating a second estimated duration of time until one of the determined parameters of the power supply reaches a recommended replacement time (RRT) backup threshold as a second estimated life value based on at least some of the determined parameter values; determining an estimated remaining life based on the two estimated life values; and indicating the determined estimated remaining life.

Description

Technical Field

[0001] The present invention relates generally to medical systems and, more particularly, to implantable medical devices having a power source. Background Art

[0002] Some types of implantable medical devices, such as pacemakers or implantable cardioverter-defibrillators, provide therapeutic electrical stimulation to a patient's heart via electrodes of one or more implanted leads. The therapeutic electrical stimulation can be delivered to the heart in the form of pulses or shocks for pacing, cardioversion, or defibrillation. In some cases, the implantable medical device can sense intrinsic depolarization of the heart and, based on this sensing, control the delivery of therapeutic stimulation to the heart. Some implantable medical devices provide cardiac sensing functionality without delivering therapy. Some implantable medical devices are used to provide therapy and / or monitor any of a number of conditions, including, for example, conditions of the nervous system or gastrointestinal system.

[0003] Cardiac resynchronization therapy (CRT) is a type of therapy delivered by an implantable medical device. CRT can help increase cardiac output by resynchronizing the electromechanical activity of the heart's ventricles. Ventricular asynchrony can occur in patients suffering from congestive heart failure (CHF).

[0004] Implantable medical devices are typically powered by internal batteries, and battery depletion is inevitable. Many implantable medical devices have the ability to communicate a "recommended replacement time" (RRT). The RRT informs the clinician that the device's power supply is approaching but has not yet reached the end of service (EOS), at which point the power supply cannot provide sufficient energy to keep the device operable. The advance warning provided by the RRT gives the clinician the opportunity to take appropriate action (e.g., replace the device before the EOS). Some implantable medical devices derive an estimate of remaining battery life, which may include periodic measurements of battery voltage, and either or both of battery impedance and current drain. Summary of the Invention

[0005] In general, the present disclosure relates to systems and techniques for determining an estimated remaining life of a power supply of an implantable medical device (IMD), such as a CRT device. The systems and techniques described herein can improve the useful life of a power supply (e.g., a battery) of an IMD. The IMD may include processing circuitry configured to indicate a power supply event (e.g., a RRT of the power supply or an EOS of the power supply). The techniques can facilitate setting the RRT to a later time than would normally be the case. For example, by setting the RRT in a plateau of a characteristic loss graph of a power supply, as further described herein, the useful capacity of the power supply can be increased, compared to techniques that set the RRT above the plateau.

[0006] In an example, a method for determining an estimated remaining life of a power supply for an implantable medical device includes: determining values of one or more parameters of the power supply and one or more operating parameters of the implantable medical device; calculating a first estimated duration of time until one of the determined parameters of the power supply reaches a pre-recommended replacement time (pre-RRT) threshold based on at least some of the determined parameter values, and adding a timer duration to determine the first estimated life value; calculating a second estimated duration of time until one of the determined parameters of the power supply reaches a recommended replacement time (RRT) backup threshold as a second estimated life value based on at least some of the determined parameter values; determining an estimated remaining life based on the two estimated life values; and indicating the determined estimated remaining life.

[0007] In an example, a medical device system for determining an estimated remaining life of a power supply includes: an implantable medical device (IMD) including a power supply; a processing circuit system configured to determine values of at least one parameter of the power supply and at least one operating parameter of the IMD, wherein the processing circuit system is configured to calculate a first estimated duration of time until at least one parameter of the power supply reaches a pre-recommended replacement time (pre-RRT) threshold based on one or more of the determined parameter values, and the processing circuit system is configured to add a timer duration to determine a first estimated life value, wherein the processing circuit system is configured to calculate a second estimated duration of time until at least one parameter of the power supply reaches a recommended replacement time (RRT) backup threshold as a second estimated life value based on one or more of the determined parameter values, and wherein the processing circuit system is configured to determine an estimated remaining life of the power supply based on the first estimated life value and the second estimated life value, and wherein the processing circuit system is configured to indicate the determined estimated remaining life.

[0008] In an example, a medical device system for indicating a recommended replacement time (RRT) for a power supply includes: an implantable medical device (IMD) including a power supply; a processing circuit system configured to determine a value of a parameter of the power supply, the processing circuit system configured to determine that the parameter has reached a pre-recommended replacement time (pre-RRT) threshold based on the determined parameter value, wherein the processing circuit system is configured to start a pre-RRT to RRT timer by controlling a timer circuit system and in response to determining that the parameter has reached the pre-RRT threshold, wherein the processing circuit system is configured to indicate the RRT in response to the earlier of the determined parameter value reaching the RRT standby threshold or expiration of the pre-RRT to RRT timer, wherein the processing circuit system is configured to start an RRT to end-of-service (EOS) timer by controlling the timer circuit system and in response to indicating the RRT, and wherein the processing circuit system is configured to indicate the EOS in response to the earlier of the determined parameter value reaching the EOS standby threshold or expiration of the RRT to EOS timer.

[0009] This summary is intended to provide an overview of the subject matter described in this disclosure. It is not intended to provide an exclusive or exhaustive explanation of the methods and systems described in detail in the following accompanying drawings and description. Details of one or more aspects of the disclosure are set forth in the following accompanying drawings and description. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] 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 become apparent from the description and drawings, and from the claims.

[0011] Figure 1 is a conceptual diagram illustrating an example medical device system;

[0012] Figure 2 It shows Figure 1 A conceptual diagram of the medical device and leads of the medical device system;

[0013] Figure 3 is a functional block diagram of an example implantable medical device for delivering CRT to a patient's heart;

[0014] Figure 4 is a functional block diagram of an example external device;

[0015] Figure 5 is shown including an external device (such as a server) and a device coupled to a network Figure 1 A block diagram of an example system of an IMD and one or more computing devices of an external device as shown in FIG;

[0016] Figure 6is a conceptual diagram showing the relationship of events (such as power service indicators);

[0017] Figure 7 is a conceptual diagram illustrating a battery discharge curve of a power service indicator;

[0018] Figure 8 is a conceptual diagram of a power supply voltage loss curve according to an example of the present invention;

[0019] Figure 9 is a conceptual diagram of a power supply voltage loss curve according to an example of the present invention;

[0020] Figure 10 is a flow chart illustrating an example technique for indicating an RRT of a power source; and

[0021] Figure 11 is a flow chart illustrating an example technique for indicating an estimated remaining life of a power supply. DETAILED DESCRIPTION

[0022] In general, the present disclosure relates to systems and techniques for determining the estimated remaining life of a power supply for an IMD. By indicating a power supply event as described herein, for example, by using a relatively large amount of energy in the second plateau of the power supply voltage curve as further described herein, the usable life of the power supply can be extended. The subject matter described herein can allow the use of such energy that was previously considered unusable due to previous deficiencies in the ability to accurately determine the remaining power supply life (e.g., due to unpredictable characteristics or manufacturing variability of the battery when it is in the second plateau region). Historically, as further described herein, the RRT was set at a voltage threshold well above the second plateau, and therefore, by using the present systems and techniques, the relative life of the power supply can be increased for the IMD, thereby avoiding unnecessary replacement procedures for the patient.

[0023] Figure 1 An example medical device system 10 is shown in connection with a patient 14. The medical device system 10 is an example of a medical device system configured to implement the example techniques described herein for determining an estimated remaining life of a power supply of an IMD (or implantable pulse generator (IPG)) and for indicating a service indicator (e.g., a power supply event), such as an RRT.

[0024] In some examples, medical device system 10 includes an implantable medical device (IMD) 16 that communicates with an external device 24. In the example shown, IMD 16 can be coupled to leads 18, 20, and 22. IMD 16 can be, for example, an implantable pacemaker that provides electrical signals to heart 12 and senses electrical activity of heart 12 via electrodes coupled to one or more of leads 18, 20, and 22. IMD 16 can provide cardiac resynchronization therapy (CRT) and can be referred to as a CRT-P device. In some examples, IMD 16 can include cardioversion or defibrillation functionality.

[0025] Leads 18, 20, 22 extend into heart 12 of patient 14 to sense electrical activity of heart 12 and / or deliver electrical stimulation to heart 12. Figure 1 In the example shown, right ventricular (RV) lead 18 extends through one or more veins (not shown), the superior vena cava (not shown), and right atrium (RA) 26 and into RV 28. Left ventricular (LV) coronary sinus lead 20 extends through one or more veins, the vena cava, right atrium 26, and into coronary sinus 30 to an area adjacent to the free wall of LV 32 of heart 12. Right atrial (RA) lead 22 extends through one or more veins and the vena cava and into RA 26 of heart 12.

[0026] IMD 16 may be coupled to at least one of leads 18, 20, 22 via an electrode ( Figure 1 14 (not shown) to sense electrical signals associated with depolarization and repolarization of heart 12. In some examples, IMD 16 may also sense electrical signals associated with depolarization and repolarization of heart 12 via extravascular electrodes (e.g., electrodes located outside the vasculature of patient 14), such as epicardial electrodes, external surface electrodes, subcutaneous electrodes, etc. The configuration of electrodes used by IMD 16 for sensing and pacing may be unipolar or bipolar.

[0027] IMD 16 may be configured to provide adaptive CRT to heart 12. In some examples, as part of adaptive CRT, IMD 16 is configured to deliver fusion pacing to heart 12 and biventricular pacing to at least one of heart 12. In some examples of fusion pacing, IMD 16 may deliver pacing stimulation (e.g., pacing pulses) to LV 32 via electrodes of lead 20, wherein the pacing stimulation is timed to achieve fusion of induced depolarization of LV 32 with intrinsic depolarization of RV 28, thereby resulting in ventricular resynchronization. In some examples, when IMD 16 is in a biventricular pacing configuration, IMD 16 may deliver pacing stimulation (e.g., pacing pulses) to RV 28 via electrodes of lead 18 and deliver pacing stimulation to LV 32 via electrodes of lead 20 in a manner that synchronizes activation and contraction of RV 28 and LV 32.

[0028] In some examples, adaptive CRT provided by IMD 16 is useful for maintaining cardiac rhythm in patient 14 with conduction dysfunction, which may occur when the natural electrical activation system of heart 12 is disrupted. The natural electrical activation system of human heart 12 involves several continuous conduction pathways that begin at the sinoatrial (SA) node and continue through the atrial conduction pathways of the bundle of Bachmann and the interatrial bundle at the level of the atria, followed by the atrioventricular (AV) node, the common bundle of His, the right and left bundle branches, and ultimately distribute to the distal myocardial terminals via a network of Purkinje fibers.

[0029] CRT delivered by IMD 16 may help alleviate heart failure conditions by restoring synchronized depolarization and contraction of one or more chambers of heart 12. In some instances, fusion pacing of heart 12 described herein enhances a patient's stroke volume by improving synchronization of RV 28 and LV 32 depolarization and contraction.

[0030] In some examples, external device 24 can be a handheld computing device or a computer workstation. External device 24 can include a user interface that receives input from a user. The user interface can include, for example, a keyboard and a display, and the display can be, for example, a cathode ray tube (CRT) display, a liquid crystal display (LCD), or a light emitting diode (LED) display. The keyboard can take the form of an alphanumeric keyboard or a group of reduced keys associated with a specific function. External device 24 can additionally or alternatively include a peripheral pointing device (such as a mouse), and the user can interact with the user interface via this peripheral pointing device. In some embodiments, the display of external device 24 can include a touch screen display, and the user can interact with external device 24 via the display.

[0031] A user, such as a physician, technician, or other clinician, may interact with external device 24 to communicate with IMD 16. For example, the user may interact with external device 24 to retrieve physiological or diagnostic information from IMD 16. The user may also interact with external device 24 to program IMD 16, e.g., to select values for operating parameters of the IMD.

[0032] For example, a user may use external device 24 to retrieve information from IMD 16 regarding the rhythm of heart 12, its trends over time, or the occurrence of arrhythmias. As another example, a user may use external device 24 to retrieve information from IMD 16 regarding other sensed physiological parameters of patient 14, such as sensed electrical activity, activity, posture, respiration, or thoracic impedance. As another example, a user may use external device 24 to retrieve information from IMD 16 regarding the performance or integrity of IMD 16 or other components of system 10, such as leads 18, 20, and 22 of IMD 16, or a power supply. In such examples, the physiological parameters of patient 14 and data related to IMD 16 may be stored in a memory of IMD 16 for retrieval by the user.

[0033] The user may use external device 24 to program the therapy schedule, select electrodes for delivering defibrillation pulses, select a waveform for the defibrillation pulses, or select or configure a fibrillation detection algorithm for IMD 16. The user may also use external device 24 to program various aspects of other therapies provided by IMD 16, such as cardioversion or pacing therapy. In some examples, the user may activate a particular feature of IMD 16 by entering a single command via external device 24, such as pressing a single key or a combination of keys on a keyboard or a single click and selection action with a pointing device.

[0034] IMD 16 and external device 24 may communicate via wireless communication using any technology known in the art. Examples of communication technologies may include, for example, radio frequency (RF) telemetry, which may be an RF link established via an antenna according to Bluetooth, WiFi, or Medical Implant Communication Service (MICS), although other technologies are also contemplated. In some examples, external device 24 may include a programming head that can be placed proximate to the patient's body near the implant site of IMD 16 to improve the quality or security of communication between IMD 16 and external device 24.

[0035] IMD 16 is an example of an IMD that can be configured to determine the estimated remaining life of the IMD's power supply. The systems and techniques described herein can increase the useful life of the IMD's power supply, which in some examples can be six months or longer. External device 24 is an example of an external device that can include processing circuitry configured to indicate a power supply event (e.g., a power supply's RRT or a power supply's EOS). The systems and techniques described herein include indicating pre-RRT (described below), RRT, and EOS.

[0036] Figure 2 is shown in more detail Figure 1 1 is a conceptual diagram of IMD 16 and leads 18, 20, 22 of medical device system 10. Leads 18, 20, 22 can be electrically coupled to therapy delivery circuitry, sensing circuitry, or other circuitry of IMD 16 via connector block 34. In some examples, proximal ends of leads 18, 20, 22 include electrical contacts that are electrically coupled to respective electrical contacts in connector block 34. Furthermore, in some examples, leads 18, 20, 22 are mechanically coupled to connector block 34 with the aid of set screws, connecting pins, or another suitable mechanical coupling mechanism.

[0037] Each of leads 18, 20, 22 includes an elongated, insulated lead body that can carry a plurality of conductors separated from one another by a tubular insulating sheath. In the example shown, bipolar electrodes 40 and 42 are positioned proximate the distal end of lead 18. Additionally, bipolar electrodes 44 and 46 are positioned proximate the distal end of lead 20, and bipolar electrodes 48 and 50 are positioned proximate the distal end of lead 22. Electrodes 40, 44, and 48 can take the form of ring electrodes, and electrodes 42, 46, and 50 can take the form of extendable spiral tip electrodes retractably mounted within insulated electrode heads 52, 54, and 56, respectively. Each of electrodes 40, 42, 44, 46, 48, and 50 can be electrically coupled to a corresponding one of the conductors within the lead body of its associated lead 18, 20, 22, and thereby coupled to a corresponding one of the electrical contacts on the proximal ends of leads 18, 20, and 22.

[0038] Electrodes 40, 42, 44, 46, 48, and 50 can sense electrical signals associated with depolarization and repolarization of heart 12. These electrical signals are conducted to IMD 16 via corresponding leads 18, 20, 22. In some examples, IMD 16 also delivers pacing pulses to LV 32 via electrodes 44, 46 to cause depolarization of cardiac tissue of heart 12. In some examples, as Figure 2As shown, IMD 16 includes one or more housing electrodes, such as housing electrode 58, which may be integrally formed with an outer surface of hermetically sealed housing 60 of IMD 16 or otherwise coupled to housing 60. In some examples, housing electrode 58 is defined by a non-insulated portion of the outwardly facing portion of housing 60 of IMD 16. Other separations between the insulated and non-insulated portions of housing 60 may be used to define two or more housing electrodes. In some examples, housing electrode 58 comprises substantially all of housing 60. Any of electrodes 40, 42, 44, 46, 48, and 50 may be used for unipolar sensing or stimulation delivery in combination with housing electrode 58. Housing 60 may enclose therapy delivery circuitry for generating cardiac pacing pulses and defibrillation or cardioversion shocks, as well as sensing circuitry for monitoring the patient's heart rhythm.

[0039] In some examples, leads 18, 20, 22 may also include elongated electrodes 62, 64, 66, respectively, which may take the form of coils. IMD 16 may deliver defibrillation pulses to heart 12 via any combination of elongated electrodes 62, 64, 66 and housing electrode 58. Electrodes 58, 62, 64, 66 may also be used to deliver cardioversion pulses to heart 12. Electrodes 62, 64, 66 may be made of any suitable conductive material, such as, but not limited to, platinum, platinum alloys, or other materials known to be useful for implantable defibrillation electrodes.

[0040] Figure 1 and Figure 2 The configuration of the medical device system 10 shown in FIG is an example and is not intended to be limiting. In other examples, instead of Figure 1 The electrodes of the transvenous leads 18, 20 and 22 shown in FIG. Figure 1 In addition to the electrodes of transvenous leads 18, 20, and 22 shown in FIG, the therapy system may include extravascular electrodes, such as subcutaneous electrodes, substernal electrodes, epicardial electrodes, or patch electrodes. Furthermore, IMD 16 need not be implanted in patient 14. In examples where IMD 16 is not implanted in patient 14, IMD 16 may deliver defibrillation pulses, pacing pulses, and other therapies to heart 12 via transcutaneous leads that extend through the skin of patient 14 to various locations within or outside of heart 12.

[0041] In other examples of medical device systems that provide electrical stimulation therapy to heart 12, the therapy system may include any suitable number of leads coupled to IMD 16, and each of the leads may extend to any location within or near heart 12. For example, the therapy system may include a dual-chamber device rather than a single-chamber device such as Figure 1In one example of a dual-chamber configuration, IMD 16 is electrically connected to a single lead that includes stimulation and sensing electrodes within LV 32 and sensing and / or stimulation electrodes within RA 26, as shown. Figure 3 In another example of a dual chamber configuration, IMD 16 is connected to two leads that extend into a respective one of RA 28 and LV 32 .

[0042] In some examples, a medical device system includes one or more intracardiac pacing devices instead of or in addition to an IMD (such as IMD 16) coupled to leads extending to heart 12. The intracardiac pacing device may include therapy delivery circuitry and processing circuitry within a housing that is configured for implantation within one of the chambers of heart 12. In such a system, multiple pacing devices, which may include one or more intracardiac pacing devices and / or an IMD coupled to one or more leads, may communicate to coordinate sensing and pacing in various chambers of heart 12 to provide CRT. The processing circuitry and memory of one or more of the pacing devices and / or another implanted medical device or external medical device may provide the functionality of the processing circuitry and memory attributed to IMD 16 herein for controlling the delivery of CRT.

[0043] Furthermore, the power monitoring techniques described in this disclosure are not limited to implementation by devices that deliver CRT or even devices used for cardiac therapy and / or monitoring. For example, the techniques of this disclosure can be implemented by neurostimulation devices or drug pumps. In general, the techniques of this disclosure can be implemented to monitor and indicate the status of the power supply of any medical device.

[0044] Figure 3 yes Figure 1 and Figure 216. FIGURE 1 is a functional block diagram of an example configuration of IMD 16. In the example shown, IMD 16 includes memory 70, processing circuitry 80, sensing circuitry 82, one or more accelerometers 84, therapy delivery circuitry 86, telemetry circuitry 88, and power supply 90, one or more of which may be disposed within housing 60 of IMD 16. In some examples, memory 70 includes computer-readable instructions that, when executed by processing circuitry 80, cause IMD 16 and processing circuitry 80 to perform various functions attributed herein to IMD 16 and processing circuitry 80. Memory 70 may include any volatile, nonvolatile, magnetic, optical, or electrical media, 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. In addition to sensed physiological parameters of patient 14 (eg, EGM or ECG signals), one or more time intervals used to time fusion pacing therapy and biventricular pacing therapy to heart 12 may be stored by memory 70 .

[0045] Processing circuitry 80 may include one or more of a microprocessor, a controller, a digital signal processing circuitry (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or equivalent discrete or integrated logic circuitry. In some examples, processing circuitry 80 may include multiple components, such as any combination of one or more microprocessors, one or more controllers, one or more DSPs, one or more ASICs, or one or more FPGAs, as well as other discrete or integrated logic circuitry. The functionality attributed to processing circuitry 80 herein may be embodied as software, firmware, hardware, or any combination thereof. Processing circuitry 80 may be configured to determine the heart rate of heart 12 based on the electrical activity sensed by sensing circuitry 82.

[0046] Processing circuitry 80 may determine one or more operating parameters of IMD 16. For example, a power operating mode may be determined (eg, a low power mode, a medium power mode, or a high power mode).

[0047] In an example, IMD operating parameters may include a procedure, such as the type of stimulation provided (e.g., cardioversion or defibrillation). In an example, such parameters may include pulse width, pacing amplitude, pacing rate, pacing percentage, or any combination described herein. These parameters may be used by processing circuitry 80 to calculate the estimated lifespan values described herein.

[0048] Sensing circuitry 82 is configured to monitor signals from at least one of electrodes 40, 42, 44, 46, 48, 50, 58, 62, 64, or 66 to monitor the electrical activity of heart 12, such as via ECG signals. For example, sensing circuitry 82 may sense atrial events (e.g., P waves) using electrodes 48, 50, 66 within RA 26 or sense LV 32 events (e.g., R waves) using electrodes 44, 46, 64 within LV 32. In some examples, sensing circuitry 82 includes switching circuitry for selecting which of the available electrodes to use to sense the electrical activity of heart 12. For example, processing circuitry 80 may select an electrode to use as a sensing electrode via switching circuitry within sensing circuitry 82 (e.g., by providing a signal via a data / address bus). In some examples, sensing circuitry 82 includes one or more sensing channels, each of which may include an amplifier. In response to a signal from processing circuitry 80, switching circuitry in sensing circuitry 82 may couple an output from a selected electrode to one of the sensing channels.

[0049] In some examples, one channel of sensing circuitry 82 may include an R-wave amplifier that receives signals from electrodes 40 and 42 used for pacing and sensing in RV 28 of heart 12. Another channel may include another R-wave amplifier that receives signals from electrodes 44 and 46 used for pacing and sensing near LV 32 of heart 12. In some examples, the R-wave amplifier may take the form of an automatic gain-controlled amplifier that provides an adjustable sensing threshold as a function of the measured R-wave amplitude of the heart rhythm. Additionally, in some examples, one channel of sensing circuitry 82 may include a P-wave amplifier that receives signals from electrodes 48 and 50 used for pacing and sensing in RA 26 of heart 12.

[0050] In some examples, the sensing circuit system 82 includes a channel that includes an amplifier having a relatively wider passband than the R-wave amplifier or the P-wave amplifier. The signal from the selected sensing electrode selected for coupling to the wideband amplifier can be provided to a multiplexer and then converted into a multi-bit digital signal by an analog-to-digital converter for storage as an EGM in the memory 70. In some examples, the storage of such EGM in the memory 70 can be under the control of a direct memory access circuit. The processing circuit system 80 can use digital signal analysis techniques to characterize the digitized signal stored in the memory 70 to detect and classify the patient's heart rhythm from the electrical signal. The processing circuit system 80 can detect and classify the patient's heart rhythm by using any of the numerous signal processing methods known in the art.

[0051] The signals generated by the sensing circuitry 82 may include, for example, an RA event signal indicating that a RA 26 ( Figure 1 ) detects a P wave; an LA event signal, which indicates that the left atrium (LA) 33 ( Figure 1 ) detected by electrodes within the RV; an RV event signal indicating that an R wave was detected via electrodes implanted within the RV 28; or an LV event signal indicating that an R wave was detected via electrodes implanted within the LV 32. Figure 1 and Figure 2 In the example of system 10 shown in , IMD 16 is not connected to electrodes implanted within LA 33. However, in other example treatment systems, IMD 16 may be connected to electrodes implanted within LA 33 to sense electrical activity of LA 33.

[0052] In some examples, IMD 16 may include one or more additional sensors, such as accelerometer 84. In some examples, accelerometer 84 may include one or more three-axis accelerometers. The signals generated by accelerometer 84 may indicate, for example, the overall body movement of patient 14, such as the patient's posture or activity level. Regardless of the configuration of accelerometer 84, processing circuitry 80 may determine patient parameter values based on the signals obtained therefrom. Accelerometer 84 may generate and provide signals to processing circuitry 80 for use in determining the posture and activity level of patient 14 at a given time. Processing circuitry 80 may then use the determined posture and activity level to further determine whether patient 14 is awake or asleep, and if it is determined that patient 14 is awake, further determine whether patient 14 is resting or exercising.

[0053] Therapy delivery circuitry 86 is electrically coupled to electrodes 40, 42, 44, 46, 48, 50, 58, 62, 64, and 66, e.g., via conductors of respective leads 18, 20, 22 or, in the case of housing electrode 58, via electrical conductors disposed within housing 60 of IMD 16. Therapy delivery circuitry 86 is configured to generate and deliver electrical stimulation therapy. For example, therapy delivery circuitry 86 may generate and deliver electrical stimulation therapy via at least two electrodes 44, 46 ( Figure 2 ) to LV 32 of heart 12 ( Figure 2 As another example, the therapy delivery circuit system 86 may deliver pacing stimulation via at least two electrodes 40, 42 ( Figure 2 ) delivers pacing stimulation to the RV 28, and via at least two electrodes 44, 46 ( Figure 2 ) delivers pacing stimulation to LV 32.

[0054] In some examples, therapy delivery circuitry 86 is configured to deliver a cardioversion shock or a defibrillation shock to heart 12. The pacing stimulation, cardioversion shock, and defibrillation shock can be in the form of stimulation pulses. In other examples, therapy delivery circuitry 86 can deliver one or more of these types of stimulation in other signal forms, such as a sine wave, a square wave, or other substantially continuous time signal.

[0055] Therapy delivery circuitry 86 may include switching circuitry, and processing circuitry 80 may use the switching circuitry, for example, via a data / address bus, to select which of the available electrodes to use to deliver defibrillation pulses or pacing pulses. The switching circuitry may include a switch array, a switch matrix, a multiplexer, or any other type of switching device suitable for selectively coupling stimulation energy to selected electrodes. In other examples, processing circuitry 80 may select a subset of electrodes 40, 42, 44, 46, 48, 50, 58, 62, 64, and 66 (with which to deliver stimulation to heart 12) without requiring switching circuitry.

[0056] Processing circuitry 80 includes timer circuitry 96, which may be embodied as hardware, firmware, software, or any combination thereof. In some examples, processing circuitry 80 is coupled to timer circuitry 96. Timer circuitry 96 may include a dedicated hardware circuit (such as an ASIC) separate from other processing circuitry 80 components (such as a microprocessor) or a software module executed by a component of processing circuitry 80 (e.g., a microprocessor or ASIC). Timer circuitry 96 may help control the delivery of pacing pulses to heart 12. Timer circuitry 96 may be configured to determine timestamps for events, determine durations between events, and start and end timers (e.g., countdowns).

[0057] In examples where IMD 16 delivers pacing pulses based on one or more AV interval values selected and / or determined by processing circuitry 80, timer circuitry 96 may include a timer for determining that an atrial pacing or sensing event (A) has occurred after processing circuitry 80 determines that an atrial pacing or sensing event (A) has occurred. P / S or more generally A) after which the selected AV interval has elapsed. The timer circuitry 96 may be configured to time the selected AV interval after a previous atrial pacing or sensing event (A) is detected by the processing circuitry 80. P / S ) upon expiration of a specified timer. Upon expiration of a specified timer, processing circuitry 80 may control therapy delivery system 86 to deliver pacing stimulation to heart 12 in accordance with a fusion pacing configuration or a biventricular pacing configuration. For example, timer circuitry 96 may generate a trigger signal that triggers output of a pacing pulse by therapy delivery system 86.

[0058] The therapy delivery circuitry 86 can deliver a cardioversion or defibrillation shock with the aid of output circuitry that determines whether to deliver a monophasic or biphasic pulse, whether the housing electrode 58 serves as the cathode or anode, and which electrodes participate in the delivery of the cardioversion or defibrillation pulse. Such functionality can be provided by one or more switches or switching circuitry of the therapy delivery circuitry 86.

[0059] Telemetry circuitry 88 includes circuitry for communicating with another device, such as external device 24 ( Figure 1 )) may be implemented using any suitable hardware, firmware, software, or any combination thereof for communicating with external devices 24. Under the control of processing circuitry 80, telemetry circuitry 88 may receive downlink telemetry from external device 24 and transmit uplink telemetry to external device 24 via an antenna, which may be internal and / or external. Processing circuitry 80 may provide data to be uplinked to external device 24 and control signals for telemetry circuits within telemetry circuitry 88, for example, via an address / data bus. In some examples, telemetry circuitry 88 may provide the received data to processing circuitry 80 via a multiplexer.

[0060] In some examples, processing circuitry 80 may transmit atrial and ventricular cardiac signals (e.g., EGM signals) generated by atrial and ventricular sense amplifier circuits within sensing circuitry 82 to external device 24. Other types of information may also be transmitted to external device 24, such as various intervals and delays for delivering CRT. External device 24 may query IMD 16 to receive cardiac signals. Processing circuitry 80 may store the cardiac signals in memory 70 and retrieve the stored cardiac signals from memory 70.

[0061] Telemetry circuitry 88 includes circuitry for communicating with another device, such as external device 24 ( Figure 1 )) any suitable hardware, firmware, software, or any combination thereof for communicating. Under the control of processing circuitry 80, telemetry circuitry 88 may receive downlink telemetry from external device 24 and send uplink telemetry to external device 24 via an antenna, which may be internal and / or external. Processing circuitry 80 may provide (e.g., via an address / data bus) data to be uplinked to external device 24 and control signals for telemetry circuits within telemetry circuitry 88. In some examples, communication circuitry 88 may provide the received data to processing circuitry 80 via a multiplexer.

[0062] The various components of IMD 16 are coupled to a power supply 90, which may include rechargeable or non-rechargeable batteries. Non-rechargeable batteries may be selected to last for up to several years, while rechargeable batteries may be charged inductively from an external device, for example, daily or weekly. In some examples, power supply 90 may include silver vanadium oxide (SVO) and lithium / carbon fluoride Li / CFx hybrid cathode batteries such as those used in IMDs (e.g., pacemakers and defibrillators). In some examples, power supply 90 may include a generally low impedance battery such as lithium magnesium dioxide (LiMnO2) or lithium silver vanadium oxide (LiSVO). Power supply 90 may exhibit a relatively long flat plateau near the end of service of power supply 90 (e.g., a second plateau, as described with respect to FIG. Figure 7 、 Figure 8 and Figure 9 By indicating a power event as described herein, the useful life of the power supply 90 may be extended, for example, by using relatively more energy in the second platform.

[0063] In some examples, processing circuitry 80 may determine values of one or more parameters of power supply 90. For example, processing circuitry may estimate current draw, determine historical voltage levels (such as stored in memory 70), instantaneous voltage levels, average voltage (e.g., over three days), or a combination of any of the parameters described herein.

[0064] In some examples, processing circuitry 80 may be configured to control timer circuitry 96 to determine a duration, a timestamp, or to control a timer or countdown. An example of a replacement indicator timer for an IMD is described in U.S. Patent Application Publication No. 2007 / 0150018 to Betzold et al., entitled “REPLACEMENT INDICATOR TIMER FOR IMPLANTABLE MEDICAL DEVICES.”

[0065] In some examples, the techniques described herein include calculating an estimated duration until a power source (e.g., power source 90) reaches a specific service indicator (such as RRT standby or EOS). An example of estimating the remaining battery service life of an IMD is described in U.S. Patent No. 8,612,167 to Schmidt et al., entitled “ESTIMATING REMAINING BATTERY SERVICE LIFE IN AN IMPLANTABLE MEDICAL DEVICE.”

[0066] Figure 4 is a functional block diagram of an example external device 24. Figure 4As shown, external device 24 includes processing circuitry 100, memory 102, a user interface 104, telemetry circuitry 106, and a power source 108. External device 24 may be a dedicated hardware device with dedicated software for interacting with IMD 16. Alternatively, external device 24 may be an off-the-shelf computing device running an application that enables external device 24 to interact with IMD 16.

[0067] A user may use external device 24 to select programmable parameters that control monitoring and therapy delivery by IMD 16, as well as to retrieve information collected by the IMD regarding the condition of patient 14 or the performance of IMD 16. The user may interact with external device 24 via user interface 104, which may include a display for presenting a graphical user interface to the user, and a keyboard or another mechanism for receiving input from the user.

[0068] Processing circuitry 100 may take the form of one or more microprocessors, DSPs, ASICs, FPGAs, programmable logic circuitry, and the like, and the functionality attributed to processing circuitry 100 herein may be embodied in hardware, firmware, software, or any combination thereof. Memory 102 may store instructions that cause processing circuitry 100 to provide the functionality attributed to external device 24 herein, as well as information used by processing circuitry 100 to provide the functionality attributed to external device 24 herein. Memory 102 may include any fixed or removable magnetic, optical, or electronic medium, such as RAM, ROM, CD-ROM, hard or floppy disks, EEPROM, and the like. Memory 102 may also include removable memory portions that can be used to provide memory updates or increase memory capacity. Removable memory also allows patient data to be easily transferred to another computing device or removed before external device 24 is used to program therapy for another patient. Memory 102 may also store information that controls therapy delivery by IMD 16, such as stimulation parameter values.

[0069] External device 24 may communicate wirelessly with IMD 16, such as using RF communication or proximal inductive interaction. Such wireless communication may be achieved using telemetry circuitry 106, which may be coupled to an internal antenna or an external antenna. The external antenna coupled to external device 24 may correspond to a programming head that may be placed on heart 12, as described above with reference to FIG. Figure 1 described.

[0070] Telemetry circuitry 106 may be similar to telemetry circuitry 88 of IMD 16 ( Figure 3). Telemetry circuit system 106 may also be configured to communicate with another computing device via wireless communication technology or directly through a wired connection. Examples of local wireless communication technologies that may be employed to facilitate communication between external device 24 and another computing device include RF communication according to the 802.11 or Bluetooth specification sets, infrared communication (e.g., according to the IrDA standard), or other standard or proprietary telemetry protocols. In this way, other external devices may be able to communicate with external device 24 without establishing a secure wireless connection.

[0071] The power supply 108 is configured to deliver operating power to the components of the external device 24. The power supply 108 may include a battery and power generation circuitry to generate the operating power. In some embodiments, the battery may be rechargeable to allow for extended operation. Recharging may be achieved by electrically coupling the power supply 108 to a cradle or plug connected to an alternating current (AC) outlet. Additionally or alternatively, recharging may be accomplished through proximal inductive interaction between an external charger and an inductive charging coil within the external device 24. In other embodiments, conventional batteries (e.g., nickel-cadmium or lithium-ion batteries) may be used. Furthermore, the external device 24 may be directly coupled to an AC outlet to power the external device 24. The power supply 108 may include circuitry for monitoring the remaining power within the battery. In this manner, the user interface 104 may provide a current battery level indicator or a low battery level indicator when the battery needs to be replaced or recharged. In some cases, the power supply 108 may be able to estimate the remaining time of operation using the current battery.

[0072] In some examples, processing circuitry 100 and memory 102 of external device 24 may be configured to provide some or all of the functionality attributed to processing circuitry 80 and memory 70 of IMD 16. For example, processing circuitry 100 may be configured to have the same or similar functionality as processing circuitry 80, such as for determining an estimated lifespan of a power supply or indicating a power supply event. In some examples, processing circuitry 100 may receive data from a memory (e.g., memory 70 of IMD 16 or memory 102 of external device 24), such as via telemetry circuitry 88 of IMD 16 and / or telemetry circuitry 106 of external device 24. In an example, processing circuitry 100 may receive IMD and / or power supply information (e.g., a voltage signal indicating a voltage change over time of a power supply (e.g., power supply 90 of IMD 16)). Processing circuitry 100 may determine whether the voltage signal satisfies a threshold and / or determine the calculation of an estimated lifespan value for the power supply, as further described herein. In some examples, processing circuitry 100 may provide an indication to a user, such as via user interface 104 (eg, a service indicator or an indication of the estimated remaining life of the power supply).

[0073] Figure 5 is a block diagram illustrating a system 110 that includes an external device 112 (such as a server) and a network 120 coupled to a Figure 1 The IMD 16 and one or more computing devices 114A-114N of the external device 24 are shown. In this example, the IMD 16 uses the telemetry circuitry 88 ( Figure 3 ) to communicate with the external device 24 via a first wireless connection and to communicate with the access point 122 via a second wireless connection. Figure 5 In the example of FIG1 , access point 122, external device 24, external device 112, and computing devices 114A-114N are interconnected and capable of communicating with one another over network 120. In some cases, one or more of access point 122, external device 24, external device 112, and computing devices 114A-114N may be coupled to network 120 via one or more wireless connections. IMD 16, external device 24, external device 112, and computing devices 114A-114N may each include one or more processing circuitry, such as one or more microprocessors, DSPs, ASICs, FPGAs, programmable logic circuitry, etc., that may perform various functions and operations, such as those described herein.

[0074] Access point 122 may comprise a device that connects to network 120 via any of a variety of connections, such as a telephone dial-up, a digital subscriber line (DSL), or a cable modem connection. In other examples, access point 122 may be coupled to network 120 via different forms of connection, including wired or wireless connections. In some examples, access point 122 may communicate with external device 24 and / or IMD 16. Access point 122 may be co-located with patient 14 (e.g., in the same room as patient 14 or on the same premises as patient 14), or may be located remotely from patient 14. For example, access point 122 may be a home monitor located in the patient's home, or may be portable for carrying by patient 14.

[0075] During operation, IMD 16 can collect, measure, and store various forms of diagnostic data. For example, IMD 16 can collect ECG and / or EGM signals and determine different CRT configurations and AV intervals. In some cases, IMD 16 can directly analyze the collected diagnostic data and generate any corresponding reports or alerts. However, in some cases, IMD 16 can transmit the diagnostic data wirelessly or via access point 122 and network 120 to external device 24, access point 122, and / or external device 112 for remote processing and analysis.

[0076] For example, IMD 16 may send data indicating whether loss of intrinsic AV conduction is detected to external device 24. External device 24 may generate a report or alarm after analyzing the data. As another example, IMD 16 may send data generated by processing circuitry 80 ( Figure 3 ) sends the system integrity indication generated by IMD 16 to external device 24, which can take further steps to determine whether a possible condition exists for one or more of leads 18, 20, and 22. For example, external device 24 can initiate a lead impedance test if such information is already available, or IMD 16 can provide the lead impedance information.

[0077] In another example, IMD 16 may provide the collected EGM data, system integrity indications, and any other relevant physiological or system data to external device 112 via access point 122 and network 120. External device 112 includes one or more processing circuitry 118. In some cases, external device 112 may request such data, and in some cases, IMD 16 may automatically or periodically provide such data to external device 112. Upon receiving diagnostic data via input / output device 116, external device 112 can analyze the data and generate a report or alert if it determines that a possible condition may exist with one or more of leads 18, 20, and 22, or with patient 14.

[0078] In one example, external device 112 may include a secure storage location for information that has been collected from IMD 16 and / or external device 24. In this example, network 120 may include an Internet network; and trained professionals (such as clinicians) may use computing devices 114A-114N to securely access the stored data on external device 112. For example, the trained professional may need to enter a username and password to access the stored information on external device 112. In one example, external device 112 may be a remote patient monitoring system, such as the one developed by Medtronic plc of Dublin, Ireland. network.

[0079] In some examples, the processing circuitry and memory of one or more of access point 122, server 112, or computing device 114 (e.g., processing circuitry 118 and memory of server 112) can be configured to provide some or all of the functionality attributed to processing circuitry 80 and memory 70 of IMD 16. For example, server 112 can be configured to store template or historical voltage values for power source 90, or one or more threshold values for power source service indicators as described below. In some examples, processing circuitry 118 can receive data from memory 70 of IMD 16, such as via telemetry circuitry 88 of IMD 16 and input / output device 116 of external device 112. In an example, processing circuitry 118 can receive a voltage signal indicating a voltage change over time of a power source (e.g., power source 90 of IMD 16). Processing circuitry 118 can determine whether the voltage signal meets a threshold value and / or determine a calculation of an estimated life value for the power source, as further described herein. In some examples, processing circuitry 118 may provide an indication (eg, a service indicator or an indication of the estimated remaining life of the power supply) to a user, such as via one or more of computing devices 114A- 114N.

[0080] Figure 6 6 is a conceptual diagram illustrating the relationship of events such as power service indicators. For example, when a manufacturer first releases a single device suitable for market release, a start of service (BOS) 610 may be indicated. The device may be implanted at the time of implantation 620, and shelf life 630 is the period between BOS 610 and implantation 620.

[0081] When an extended service period (PSP) 690 has elapsed and performance to design specifications cannot be guaranteed, an end of service (EOS) 680 may be indicated. The PSP 690 may be a period of time beyond the RRT 660 during which the IMD continues to function as defined by the manufacturer for extended primary bradyarrhythmia pacing.

[0082] The predicted service life (PSL) 640 may be the period of time from implantation of the IMD to the recommended replacement time (RRT) 660 under defined conditions. The RRT 660 may be indicated when the power indicator reaches a value set by the manufacturer of the IMD for its recommended replacement. The RRT may also indicate entry into the PSP 690.

[0083] The optional replacement indicator (ERI) 670 may be a secondary indicator intended to inform the user that the equipment has less than 90 days of service remaining. The ERI 670 is not a definition of the European Committee for Electrical Standardization (CENELEC).

[0084] Pre-recommended replacement time (pre-RRT) 650 is not CENELEC defined (eg, pre-RRT 650 may be used internally by system 10) and is not necessarily displayed to the user. Pre-RRT 650 may indicate that the mains voltage is transitioning from a first level to a second level.

[0085] Figure 7 The timing of these defined events relative to an exemplary battery discharge curve is shown in FIG. Figure 7 As shown, a first shelf or platform extends for a certain period of time until the battery discharge curve decreases rapidly, while a second shelf or platform extends for a shorter period of time.

[0086] Figure 7 It shows Figure 6 6. A conceptual diagram of a battery discharge curve illustrating example power service indicators is shown. For example, a first shelf 710 (e.g., first platform 710) and a second shelf 720 (e.g., second platform 720) are shown relative to example power indicators (e.g., BOS 610, pre-RRT 650, RRT 660, ERI 670, and EOS 680). After EOS 680, the power supply may not be able to adequately power the circuitry of the IMD.

[0087] Figure 8 FIG is a conceptual diagram of a power supply voltage curve (eg, a battery discharge curve) according to an example of the present disclosure. Figure 8 An example second platform 720 is shown in FIG. Figure 8 The example shows a method for indicating a power source (e.g., Figure 3 The present invention also provides a technique for detecting an event (e.g., RRT or EOS) of the power supply 90. For example, the processing circuit system (e.g., processing circuit system 80, 100, or 118) can determine the value of a parameter of the power supply. In some examples, the parameter can be a voltage, such as an instantaneous voltage. In an example, the parameter is an average voltage, such as an average voltage measured over a period of several days (e.g., 1 to 5 days, such as 3 days). Similarly, the parameter can be current usage at certain times or over a period of time, the rate of battery loss, historical loss (e.g., before recharging the power supply), a template loss curve (e.g., the first and second plateau curves described herein), or another parameter or a combination of multiple parameters.

[0088] The processing circuitry may be configured to determine that the parameter reaches a pre-RRT threshold based on the determined parameter value of the power supply. Figure 8In the example of FIG, the pre-RRT threshold may be approximately 2.625 volts, and the processing circuitry may indicate a pre-RRT at a time corresponding to the event 850. In other examples, the pre-RRT threshold may be greater than or less than 2.625 volts, such as from 2.615 to 2.635 volts. Other values may be used for the pre-RRT threshold.

[0089] In response to determining that the parameter (e.g., voltage) reaches the pre-RRT threshold, the processing circuitry may control the timer circuitry (e.g., timer circuitry 96) to start a pre-RRT to RRT timer. Figure 8 In the example of FIG, the pre-RRT to RRT timer 855 is shown as extending from the pre-RRT 850 to the expiration 852 of the pre-RRT to RRT timer 855. In this example, the RRT backup 868 threshold is shown as occurring after the expiration 852. In some examples, the RRT is indicated as the earlier of the expiration 852 of the pre-RRT to RRT timer 855 or the time when the RRT backup 868 threshold is reached. Figure 8 In the example shown, RRT 860 is indicated at the expiration 852 of the pre-RRT to RRT timer 855, which may be before the RRT standby 868 threshold. The RRT standby 868 voltage threshold may be approximately 2.600 volts. In some examples, the RRT standby 868 threshold may be greater than or less than 2.600 volts. In some examples, the RRT standby 868 is set within the second platform 720.

[0090] In response to indicating RRT 860, the processing circuit system may be configured to start RRT to EOS timer 865. The drawings are not necessarily drawn to scale, and therefore, although pre-RRT to RRT timer 855 may appear shorter than RRT to EOS timer 865, they may be of the same or similar duration. In other examples, Figure 8 The timers of the examples may have different durations. Figure 8 As described, each of timer 855 and timer 865 can have any desired duration (e.g., less than 90 days, 90 days, 180 days, or more than 180 days). The processing circuitry can be configured to indicate EOS in response to the earlier of expiration of RRT to EOS timer 865 or the parameter reaching the EOS backup 888 threshold voltage. Thus, in this example, EOS 880 is indicated at a time corresponding to expiration 882 of RRT to EOS timer 865.

[0091] Thus, depending on the particular profile of the power loss, RRT 860 and / or EOS 880 may be indicated by the processing circuitry prior to the corresponding previous timer.

[0092] Figure 9 : is a conceptual diagram of a power supply voltage loss curve according to an example of the present disclosure. Figure 9 An example of a first platform 710 and a second platform 720 is shown in FIG. Figure 9 The example of FIG. 1 shows a technique for determining an estimated remaining life of a power supply (e.g., power supply 90) of an IMD. Instantaneous time 922 can represent a time and a corresponding voltage value at a current time (e.g., the time at which the estimated remaining life of the power supply is measured). As described herein, processing circuitry can be configured to determine one or more parameters of a power supply and one or more operating parameters of an IMD (e.g., IMD 16).

[0093] Based on at least some of the determined parameter values, the processing circuitry may be configured to calculate a first estimated duration 992 until one of the determined parameters of the power supply (e.g., voltage or another described above) reaches the pre-RRT threshold 950. The processing circuitry may add a timer duration 994 to the first estimated duration 992 to determine a first estimated lifetime value (e.g., the duration from the instantaneous time 922 to the expiration of the timer duration 994).

[0094] Based on at least some of the determined parameter values (e.g., parameter values of the power supply and / or the IMD), the processing circuitry may be configured to calculate a second estimated duration 996 until one of the determined parameters of the power supply reaches the RRT backup threshold 968. The processing circuitry may determine the second estimated duration 996 as a second estimated lifetime value.

[0095] exist Figure 9 In an example, the processing circuit system can be configured to determine an estimated remaining life of the power supply based on the first and second estimated life values. In some examples, the processing circuit system compares the first estimated life value with the second estimated life value. The processing circuit system can determine to use the smaller of the first estimated remaining life value and the second estimated remaining life value as the estimated remaining life of the power supply. For example, Figure 9 As shown in , the estimated remaining lifetime end time corresponds to point 999, where the estimated remaining lifetime lasts from instantaneous time 922 to point 999. The processing circuitry may be configured to indicate (eg, via a notification) the determined estimated remaining lifetime.

[0096] In other examples, the processing circuitry may determine to use another estimated remaining life value as the estimated remaining life of the power supply. For example, the processing circuitry may instruct to use the larger of the first estimated remaining life value and the second estimated remaining life value. In an example, the processing circuitry may instruct to use the average of the first estimated remaining life value and the second estimated remaining life value. In an example, the processing circuitry may use a function based on the first estimated remaining life value and the second estimated remaining life value, such as a function that may include one or more weighting factors, as the estimated remaining life of the power supply. These and other examples of determining the estimated remaining life of the power supply may be used in any combination.

[0097] In some examples, the processing circuitry determines the estimated remaining life before indicating pre-RRT (e.g., at instant 922). In other examples, such as when the instant occurs during timer duration 994, the processing circuitry determines the estimated remaining life as the lesser of the remaining duration of timer duration 994 or the duration until a second estimated life value (e.g., RRT backup 968 time).

[0098] In some examples, the one or more operating parameters of the implantable medical device can be at least one of a depth of discharge, a stimulation parameter, or a bioelectrical sensing parameter.Timer duration 994 can be 180 days, or any other duration described herein.

[0099] exist Figure 8 and Figure 9 In the example of , the horizontal axis is time (such as may be measured in days, weeks, months, or years) and the vertical axis is shown as voltage, but in other examples the vertical axis may be another parameter of a power supply as described herein.

[0100] Figure 10 is a flow chart illustrating an example technique for indicating an RRT of a power source. In some examples, an IMD (e.g., Figure 1 The IMD 16, such as via the processing circuitry 80, may determine values of one or more parameters of the IMD's power supply (1002). Figure 8 As described, for example, if the voltage level of the power supply meets the pre-RRT threshold, the process can determine that the pre-RRT has been met (Yes at 1004). In response, the processing circuit system can indicate the pre-RRT and start the pre-RRT to RRT timer (1006). For example, the processing circuit system can control the timer circuit system (e.g., timer circuit system 96) to start the timer (e.g., count down from 180 days). The processing circuit system can continue to determine the value of one or more parameters of the power supply (1008).

[0101] The processing circuit system can determine that the RRT standard has been met (yes of 1010). For example, an RRT standard may include the expiration of a pre-RRT to RRT timer. In an example, the RRT standard may include the voltage level of the power supply reaching (e.g., reaching or exceeding) the RRT standby voltage threshold. Other standards can be used to determine that the RRT standard has been met. In an example, if any standard is met, such as a first standard to be met in time, the processing circuit system can determine that the standard has been met. In response to meeting the RRT standard, the processing circuit system can indicate RRT and start the RRT to EOS timer (1012). For example, the processing circuit system can control the timer circuit system to start the timer, as described herein. The processing circuit system can continue to determine the value of one or more parameters of the power supply (1014).

[0102] The processing circuitry may determine that an EOS criterion has been met (Yes at 1016). For example, the EOS criterion may include expiration of an RRT to EOS timer. In an example, the EOS criterion may include the voltage level of a power supply reaching an EOS standby voltage threshold. Other criteria may be used to determine that an EOS criterion has been met. In an example, if any criterion is met, such as a first criterion to be met in time, the processing circuitry may determine that the criterion has been met. In response to the EOS criterion being met, the processing circuitry may indicate an EOS (1018).

[0103] Figure 11 1 is a flow chart illustrating an example technique for indicating an estimated remaining life of a power supply. An IMD (e.g., IMD 16, such as via processing circuitry 80) may determine values of one or more power supply parameters and values of one or more IMD parameters (1102). Such parameters (e.g., power supply parameters and / or IMD parameters) may be any of the parameters described herein. The parameters may be instantaneous or measured over time, such as an average or other statistical measure. In some examples, the parameters may be based on a function and determined by the processing circuitry. In some examples, the parameters may be based on information stored in a memory of the IMD (such as historical data or template data related to the parameters).

[0104] In an example, the processing circuitry may calculate a first estimated lifetime value and a second estimated lifetime value (1104). Figure 9 For example, the first estimated lifetime value may be the expiration of the timer duration 994 , while the second estimated lifetime value may correspond to the RRT standby 968 threshold voltage.

[0105] In an example, the processing circuitry may determine the smaller of the first estimated lifetime value and the second estimated lifetime value (1106). For example, the processing circuitry may compare the first estimated lifetime value and the second estimated lifetime value to determine the smaller one. In an example, for example, if the values are the same (e.g., the same or nearly the same), the processing circuitry may indicate either one or may indicate the one with a higher certainty estimate.

[0106] In an example, the processing circuitry may indicate the estimated remaining life of the power supply of the IMD as a smaller estimated life value (1108). Figure 9 In the example of , the smaller estimated life value is the RRT backup 968 value and is therefore indicated as the estimated remaining life as of instant time 922.

[0107] Various aspects of the technology may be implemented within one or more processing circuitry, including one or more microprocessors, DSPs, ASICs, FPGAs, or any other equivalent integrated or discrete logic circuitry, as well as any combination of such components implemented in external devices, such as physician or patient external devices, electrical stimulators, or other devices. The term "processing circuitry" may generally refer to any of the foregoing logic circuitry, alone or in combination with other logic circuitry, or any other equivalent circuitry.

[0108] In one or more examples, the functions described in this disclosure may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, these functions may be stored as one or more instructions or codes on a computer-readable medium and executed by a hardware-based processing unit. The computer-readable medium may include a computer-readable storage medium forming a tangible non-transient medium. The instructions may be executed by one or more processing circuit systems (such as, one or more DSPs, ASICs, FPGAs, general-purpose microprocessors, or other equivalent integrated or discrete logic circuit systems). Therefore, the term "processing circuit system" as used herein may refer to any one of the aforementioned structures or one or more of any other structures suitable for implementing the technology described herein.

[0109] In addition, in some aspects, the functions described herein may be provided within dedicated hardware and / or software modules. Depicting different features as modules or units is intended to emphasize different functional aspects and does not necessarily imply that such modules or units must be implemented by separate hardware or software components. Instead, the functions associated with one or more modules or units may be performed by separate hardware or software components, or may be integrated within common or separate hardware or software components. Moreover, these techniques may be fully implemented in one or more circuits or logic elements. The technology disclosed herein may be implemented in a wide variety of devices or apparatuses (including an IMD, an external device, a combination of an IMD and an external device, an integrated circuit (IC) or a group of ICs resident in the IMD and / or the external device, and / or a discrete circuit system).

[0110] Various aspects of the disclosure have been described. These and other aspects are within the scope of the following claims.

Claims

1. A method for determining an estimated remaining life of a power supply of an implantable medical device, the method comprising: determining values of one or more parameters of the power supply and one or more operating parameters of the implantable medical device; calculating a first estimated duration based on at least some of the determined values of the one or more parameters of the power supply and the one or more operating parameters of the implantable medical device and adding a timer duration to determine a first estimated life value, wherein the calculated first estimated duration extends from a current time to a time when the one or more parameters of the power supply reach a pre-recommended replacement time (pre-RRT) threshold; calculating a second estimated duration as a second estimated lifetime value based on the at least some of the determined values of the one or more parameters of the power supply and the one or more operating parameters of the implantable medical device, wherein the calculated second estimated duration extends from a current time to a time when the one or more parameters of the power supply reach a recommended replacement time (RRT) standby threshold; determining the estimated remaining life based on the first estimated life value and the second estimated life value; as well as Indicates the determined estimated remaining life.

2. The method of claim 1 , wherein determining the estimated remaining life based on the first estimated life value and the second estimated life value comprises: The estimated remaining life is determined as the lesser of the first estimated life value and the second estimated life value.

3. The method of claim 2, wherein the estimated remaining life is determined to be the smaller of the first estimated life value and the second estimated life value before the pre-RRT threshold.

4. The method of any one of claims 1-3, wherein the one or more operating parameters of the implantable medical device include at least one of: a depth of discharge, a stimulation parameter, or a bioelectrical sensing parameter.

5. The method according to claim 1 or 2, further comprising: During the timer duration, comparing a remaining duration of the timer duration with a duration until the second estimated lifetime value; as well as The determined estimated remaining life is indicated as the lesser of the remaining duration and the second estimated life value. 6 . The method of claim 1 , wherein the one or more parameters of the power supply include at least one of an instantaneous battery voltage or an average battery voltage.

7. The method of claim 1, wherein the pre-RRT threshold is approximately 2.625 volts.

8. The method of claim 1, wherein the RRT standby threshold is approximately 2.600 volts.

9. The method of claim 1, wherein the timer has a duration of 180 days.

10. A medical device system for determining an estimated remaining life of a power supply, the medical device system comprising: an implantable medical device IMD, the IMD comprising the power supply; processing circuitry configured to: determining values of one or more parameters of the power supply and one or more operating parameters of the IMD, calculating a first estimated duration based on at least some of the determined values of the one or more parameters of the power source and the one or more operating parameters of the implantable medical device, and adding a timer duration to determine a first estimated lifetime value, wherein the calculated first estimated duration extends from a current time to a time when the one or more parameters of the power source reach a pre-recommended replacement time (pre-RRT) threshold, calculating a second estimated duration as a second estimated lifetime value based on at least some of the determined values of the one or more parameters of the power supply and the one or more operating parameters of the implantable medical device, wherein the calculated second estimated duration extends from a current time to a time when the one or more parameters of the power supply reach a recommended replacement time (RRT) backup threshold, and determining the estimated remaining lifetime of the power supply based on the first estimated lifetime value and the second estimated lifetime value, and Indicates the determined estimated remaining life.

11. The medical device system of claim 10, wherein the one or more parameters of the power supply include at least one of an instantaneous battery voltage or an average battery voltage.

12. The medical device system of claim 10, wherein the pre-RRT threshold is approximately 2.625 volts.

13. The medical device system of claim 10, wherein the RRT standby threshold is approximately 2.600 volts.

14. The medical device system of claim 10, wherein the timer has a duration of 180 days.

15. The medical device system of claim 10 , wherein the processing circuitry is configured to determine the estimated remaining life of the power supply by determining the smaller of the first estimated life value and the second estimated life value, and wherein the processing circuitry is configured to indicate the smaller of the two as the estimated remaining life.

16. A medical device system as described in claim 10 or 15, wherein the processing circuit system is configured to: compare the remaining duration of the timer duration with the duration until the second estimated life value during the timer duration, and indicate that the determined estimated life of the power supply is the smaller of the two.

17. The medical device system of claim 10 or 15, wherein the at least one parameter of the power supply comprises a voltage curve of the power supply over time, the voltage curve comprising a first plateau and a second plateau, and wherein the RRT backup threshold occurs in the second plateau.

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