Implantable medical device for discriminating between an active phase and a resting phase of a patient

Abstract

The invention relates to an implantable medical device (1) for discriminating between an active phase and a resting phase of a human or animal patient. During operation, the implantable medical device (1) carries out the following steps: a) determining, with a detection unit (31), at least two of the following parameters of a patient carrying the implantable medical device (1) in an implanted state: i) an acceleration, ii) an impedance of a body structure, iii) a body temperature, and iv) a cardiac rate; b) comparing the at least two determined parameters with predeterminable thresholds, wherein an individual predeterminable threshold is assigned to each parameter; and c) classifying a physical state of the patient as a resting phase if at least two of the following criteria are fulfilled: i) the determined acceleration lies below a first predeterminable threshold, ii) the determined impedance lies below a second predeterminable threshold, iii) the determined body temperature lies below a third predeterminable threshold, and iv) the determined cardiac rate lies below a fourth predeterminable threshold; otherwise classifying the physical state of the patient as an active phase.

Description

[0001] Applicant: BIOTRONIK SE & Co. KG

[0002] Date: 27.11.2025

[0003] Our Reference: 24.078P-WO

[0004] IMPLANTABLE MEDICAL DEVICE FOR DISCRIMINATING BETWEEN AN

[0005] ACTIVE PHASE AND A RESTING PHASE OF A PATIENT

[0006] The present invention relates to an implantable medical device according to the preamble of claim 1 and to a method for discriminating between an active phase and a resting phase of a patient according to the preamble of claim 15.

[0007] Implantable medical devices for stimulating a human or animal heart, such as pacemakers, have been known for a long time. They can perform different functions. Different stimulation programs can be carried out by an appropriate pacemaker to restore the treated heart to a normal state.

[0008] To give an example, pacemakers can be used as defibrillation system. Such a defibrillation system, also known as an implantable cardioverter-defibrillator (ICD), is used to recognize and treat potentially life-threatening cardiac arrhythmias (ventricular tachycardia, bradycardia, ventricular fibrillation). Such a defibrillation system is implanted in a patient in such a way that one or more electrode leads extend from a defibrillation generator to the human heart in order to detect signals for the purpose of recognizing cardiac arrhythmia and to emit stimulation energy, in particular to cause an electric shock (defibrillation). Both the electrode leads and the defibrillation generator are permanently implanted and remain in the patient for a long period of time, usually several years.

[0009] It is important to safely differentiate between a resting phase of a patient and an active phase of the patient to be able to perform diagnostic tasks and to apply therapeutic stimulations in such a phase in which the diagnosis or therapy is particularly efficient and reliable. This is not only true for ICDs, but also for other cardiac implants and further implantable medical devices for monitoring body functions of the patient and / or for applying therapy to a patient. It is an object of the present invention to provide an implantable medical device that enables, during its operation, a discrimination between an active phase and a resting phase of a human or animal patient.

[0010] This object is achieved with an implantable medical device having the features of claim 1. Such an implantable medical device serves for discriminating between an active phase and a resting phase of a human or animal patient. The implantable medical device comprises a processor, a memory unit, and a detection unit. The detection unit serves for detecting at least two of the following parameters of the patient that carries the implantable medical device in an implanted state: i) an acceleration (of the body of the patient), ii) an impedance of a body structure, iii) a body temperature, and iv) a cardiac rate.

[0011] According to an aspect of the present invention, the memory unit comprises a computer- readable program that causes the processor to perform the steps explained in the following when being executed on the processor.

[0012] In a first step, at least two of the following four parameters of the patient carrying the implantable medical device in an implanted state are determined with the detection unit: i) an acceleration, ii) an impedance of a body structure (such as the thorax), iii) a body temperature, and iv) a cardiac rate.

[0013] Afterwards, the at least two determined parameters are compared with predeterminable thresholds. In this context, an individual predeterminable threshold is assigned to each parameter.

[0014] Subsequently, a physical state of the patient is classified either as a resting phase or as an active phase. In this context, the physical state of the patient is classified as resting phase if at least two of the following criteria are fulfilled: i) the determined acceleration lies below a first predeterminable threshold, ii) the determined impedance lies below a second predeterminable threshold, iii) the determined body temperature lies below a third predeterminable threshold, and iv) the determined cardiac rate lies below a fourth

[0015] 24.078P-WO / 27.11.2025 predeterminable threshold. If not at least two of these parameters are fulfilled, the physical state of the patient is classified as an active phase.

[0016] This classification of the physical state of the patient as either a resting phase (resting state) or an active phase (active state) enables to define measuring time points or measuring windows for specific functionalities of the implantable medical device and likewise helps to identify activation time points or activation windows for specific functionalities of the implantable medical device, e.g., realized by algorithms activated at or during those measuring time points or measuring windows. By performing specific measurements or functionalities of the implantable medical device at particularly appropriate measuring time points or within particularly appropriate measuring windows, the power consumption of the implantable medical device can be reduced. This safes battery power and increases battery lifetime and thus increases the overall lifetime of the implantable medical device. Consequently, it makes the application of the implantable medical device more user-friendly since an exchange of the implantable medical device is only necessary after an extended period of time in comparison with prior art devices. In addition, performing measurements or carrying out specific functionalities during particularly appropriate time windows or at particularly appropriate time points increases the quality of these measurements and / functionalities and thus increases the overall reliability and usability of the implantable medical device.

[0017] In an embodiment, the acceleration can be determined within a first dynamic range. In this embodiment, the first predeterminable threshold corresponds to a value of 10 % to 35 %, in particular of 15 % to 30 %, in particular of 20 % to 25 %, in particular 20% of the first dynamic range. If the determined acceleration lies above this first predeterminable threshold, this is an indication that the patient is under physical stress (e.g., due to climbing stairs or due to walking). Therefore, his or her physical state would rather be considered to corresponds to an active phase. However, since an elevated acceleration could also have other reasons, the classification of the physical state of the patient as resting phase would still be possible if two other of the above-mentioned criteria would be fulfilled.

[0018] 24.078P-WO / 27.11.2025 In an embodiment, the impedance can be determined within a second dynamic range of a normalized area difference between an impedance reference curve and a currently measured impedance curve. In this embodiment, the second predeterminable threshold has a value of 10 % to 35 %, in particular of 15 % to 30 %, in particular of 20 % to 25 %, in particular 20% of the second dynamic range. If the determined impedance lies above the second predeterminable threshold, this is an indication that the patient is under physical and / or mental stress which is the reason for a reduced contractility of the heart and / or other muscles. Such reduced contractility can be measured by an increased impedance. However, such an increased impedance cannot be fully decisive for determining the patient’s physical state. Rather, if two of the other criteria are fulfilled, the patient’s physical state can be classified as a resting phase even if an increased impedance has been measured.

[0019] In an embodiment, the third predeterminable threshold is dependent on an average body temperature measured during the last 1 hour to 24 hours, in particular the last 6 hours to 20 hours, in particular the last 8 hours to 18 hours, in particular the last 10 hours to 16 hours, in particular the last 12 hours to 14 hours. According to an embodiment, the third predeterminable threshold is determined by a difference of the currently measured body temperature and the average body temperature, then set to be 0.1 K to 1 K, in particular 0.2 K to 0.9 K, in particular 0.3 K to 0.8 K, in particular 0.4 K to 0.7 K, in particular 0.5 K to 0.6 K below this average value of the temperature. If the body temperature lies at or above the average body temperature, this indicates an active phase of the patient. In contrast, a lower body temperature is indicative for a resting phase of the patient. Together with further information from at least one other measured parameter, the physical state of the patient can then be classified as active or resting.

[0020] In an embodiment, the fourth predeterminable threshold depends on an average value of the cardiac rate of the patient that is calculated from values obtained in the last 1 hour to 24 hours, in particular the last 6 hours to 20 hours, in particular the last 8 hours to 18 hours, in particular the last 10 hours to 16 hours, in particular the last 12 hours to 14 hours. The fourth predeterminable threshold is a value lying 1 bpm to 10 bpm, in particular 2 bpm to 9 bpm, in particular 3 bpm to 8 bpm, in particular 4 bpm to 7 bpm, in particular 5 bpm to 6 bpm, in particular 5 bpm below the average value of the cardiac rate. An average value calculated

[0021] 24.078P-WO / 27.11.2025 for the whole day (i.e., 24 hours) is a particularly appropriate measure for determining the fourth predeterminable threshold. A cardiac rate lying at or above the average value indicates physical activity and thus an active state of the patient. If, however, the cardiac rate lies below the fourth predeterminable threshold, this indicates physical and mental inactivity and thus a resting phase of the patient.

[0022] In an embodiment, the acceleration and the impedance of a body structure are determined as the at least two parameters. It turned out that these two parameters are particularly helpful for distinguishing an active phase from a resting phase of the patient. When the acceleration and the impedance of a body structure are taken as parameters, it is often not necessary (but still possible) to measure any other of the parameters to increase the reliability of the classification.

[0023] In an embodiment, at least three of the parameters are determined with the detection unit, and the physical state of the patient is classified as a resting phase if at least three of the criteria explained above are fulfilled. Thus, in this embodiment, it is not sufficient if only two of the parameters are determined and two of the criteria are fulfilled to classify the physical state of the patient as resting phase. Rather, three parameters need to fulfil the above-mentioned criteria. Thus, the requirements for classifying the physical state as resting phase are higher in this embodiment. Consequently, the classification of the physical state as resting state can be typically achieved with a higher specificity (i.e., there are less falsenegative results in which the physical state is erroneously classified as active phase of the patient who is in fact in a resting phase).

[0024] In an embodiment, the at least three parameters comprise the acceleration, the impedance, and the body temperature. In an embodiment, the three parameters comprise the acceleration, the impedance, and the cardiac rate.

[0025] In an embodiment, the computer-readable program causes the processor to activate a unit, a functionality, or an algorithm of the implantable medical device only if the physical state of the patient is classified as resting phase. Due to this classification-based activation of the unit, the functionality and / or the algorithm, the benefits of the presently described invention

[0026] 24.078P-WO / 27.11.2025 can be realized in a particularly appropriate way. Then, it is guaranteed that a specific unit, functionality and / or algorithm is only active if the physical state of the patient allows a particularly appropriate operation of this unit, functionality and / or algorithm so that the above-mentioned benefits with respect to lifetime and usability of the implantable medical device particularly appropriate achieved.

[0027] In an embodiment, the unit, the functionality, and / or the algorithm has a comparatively high power consumption. Expressed in other words, the unit, the functionality, and / or the algorithm has an average power consumption lying above a fifth predeterminable threshold. It is particularly helpful to activate such unit, functionality, and / or algorithm only in resting phases of the patient to avoid an undesired loss of energy if the unit, the functionality, and / or the algorithm works better during resting phases of the patient than during active phases.

[0028] In an embodiment, the fifth predeterminable threshold is a power consumption lying in a range of 0,1 pWh to 50 pWh, in particular 0,15 pWh to 5 pWh, in particular 0,2 pWh to 2,5 pWh, in particular 0,3 pWh to 1 pWh, in particular 0,4 pWh to 0,75 pWh, in particular 0,17 pWh to 0,5 pWh, in particular 0,5 pWh.

[0029] In an embodiment, the unit is a sleep apnea detection unit and / or the functionality is a sleep apnea detection and / or the algorithm is a sleep apnea detection algorithm. Such a sleep apnea detection typically has a quite high power consumption since it requires, in an embodiment, a continuous measurement of the thoracic impedance. However, it makes only sense to perform such a sleep apnea detection if the patient is indeed sleeping, i.e. during a resting phase. As long as the patient is in an active phase, performing a sleep apnea detection would be an unnecessary waste of power or energy. The presently claimed and described implantable medical device enables an activation of the sleep apnea detection only in such resting phases of the patient in which a sleep apnea detection really makes sense. This results in a much better power management of the implantable medical device and thus a longer lifetime and usability of the implantable medical device.

[0030] In an embodiment, the unit is a data communication unit and / or the functionality is a data communication ability and / or a signalization of a reception standby for a remote follow-up query and / or the algorithm is a data communication algorithm. Data communication and

[0031] 24.078P-WO / 27.11.2025 standby for a remote follow-up query typically require quite a significant amount of energy. However, the data communication works much more reliable and with less power expenditure if the patient is a resting phase. Then, no movements of the patient impair the quality of the data communication. Consequently, the data communication can be realized within a shorter time period, with a higher data transfer quality and with a lower power consumption than in an active phase of the patient in which the relative position between the implantable medical device and an external data communication device is changed.

[0032] In an embodiment, the data communication unit serves for transferring data to an evaluation unit (or a different receiver) in a wireless manner. All standard data transmission protocols or specifications are appropriate for such a wireless data communication. Examples of standard data transmission protocols or specifications are the Medical Device Radiocommunications Service (MICS), the Bluetooth Low Energy (BLE) protocol, the Zigbee specification, the long range wide area network (LoRaWAN) protocol, the wireless personal area network (WPAN) specification, the low-power wide-area network (LPWAN) specification, the wireless local area network (WLAN) specification, the Global System for Mobile Communications (GSM) specification, the Long-Term Evolution (LTE) standard, and the fifth-generation technology standard for broadband cellular networks (5G).

[0033] In an embodiment, the functionality is an initiation of a routine measuring task and / or the algorithm is a routine measuring task algorithm. Such routine measuring tasks like determining a sensing amplitude, determining a stimulation threshold, performing timing / interval statistics (e.g., determining the intrinsic atrioventricular conduction time during rest) can be well done when there is typically no need for other therapeutic tasks of the implantable medical device since the patient is in a resting phase. The computing capacity, power availability and possibility of undisturbed signal measurements can then be exploited in a particularly appropriate way.

[0034] In an embodiment, the functionality is a consolidation and / or compression of data and / or the algorithm is a data consolidation and / or data compression algorithm. Such consolidation and / or compression of data (e.g., the transfer of data from a random access memory (RAM) into an electrically erasable programmable read-only memory (EEPROM) (like, e.g., a flash

[0035] 24.078P-WO / 27.11.2025 memory) can be done in a particularly appropriate way if the implantable medical device is not required to perform other tasks. This is typically the case during a resting phase of the patient, whereas the processor of the implantable medical device is under load - e.g. due to a therapy to be applied - during an active phase of the patient. Consequently, it is beneficial to perform such data consolidation and / or data compression tasks during the resting phase of the patient.

[0036] In an embodiment, the computer-readable program causes the processor to initiate a continuous measuring of the thoracic impedance of the patient for determining a breathing frequency of the patient upon having classified the physical state of the patient as resting phase. During the resting phase, a close monitoring of the breathing frequency of the patient can be used for a sleep apnea detection. If sleep apnea is detected, the implantable medical device can perform an appropriate countermeasure to terminate the sleep apnea episode. Alternatively, the duration and frequency of sleep apnea episodes can be stored within the memory unit of the implantable medical device and can be read out at a later point to learn more about the patient’s breathing behavior during sleep. Such information can be helpful in subsequent steps in which the physician initiates appropriate countermeasures against these sleep apnea episodes.

[0037] In an embodiment, the computer-readable program causes the processor to stop the continuous measuring of the thoracic impedance at least preliminarily upon having classified the physical state of the patient again as active phase. Such at least provisionally stop of the continuous measuring of the thoracic impedance in case of an at least temporal shift of the physical state of the patient from a resting phase to an active phase is expedient since a continuous measurement of the thoracic impedance requires a lot of power and does not make sense if the patient does not sleep any longer.

[0038] In an embodiment, the computer-readable program causes the processor to resume the continuous measuring of the thoracic impedance if the physical state of the patient is again classified as resting phase within a predeterminable first time period after having classified the physical state of the patient as active phase. Thus, if the patient falls back into a resting phase after short active phase episode, the overall physical state of the patient can be

[0039] 24.078P-WO / 27.11.2025 classified as resting phase, namely, as intermittent resting phase. A short restless sleep phase can be the reason for a temporal classification of the physical state of the patient as active phase. Upon falling back into a deeper sleep phase, the resumption of the continuous thoracic impedance measurement makes sense since this allows a breathing frequency analysis during the further resting or sleeping phase. If, on the other hand, the patient remains in an active phase also after lapse of the first predeterminable time period, this indicates that the resting phase has indeed been terminated. Then, the final termination of the continuous thoracic impedance measurements makes sense to reduce the power consumption of the implantable medical device. If the at least two criteria are again fulfilled at a later time point, this would initiate a novel start of the continuous measuring of the thoracic impedance which would then, however, be counted as different resting phase episode of the patient.

[0040] In an embodiment, the first predeterminable time period is a time period lying in a range of 1 minute to 10 minutes, in particular 2 minutes to 9 minutes, in particular 3 minutes to 8 minutes, in particular 4 minutes to 7 minutes, in particular 5 minutes to 6 minutes.

[0041] In an embodiment, the active phase is a sportive phase and / or a working phase and / or a recovery phase of the patient. In this context, the resting phase is a sleeping phase. Thus, the implantable medical device enables a discrimination between a sleeping phase and a nonsleeping phase of the patient, in particular between a sleeping phase on the one hand and a sportive phase, a working phase, and / or a recovery phase on the other hand.

[0042] In an embodiment, the implantable medical device further comprises a stimulation unit that is configured to stimulate the patient’s heart. In this embodiment, the implantable medical device further comprises a ventricular electrode for providing stimulation pulses to a ventricle of the patient’s heart. The ventricular electrode optionally also serves for detecting ventricular electric signals, e.g., for determining the cardiac rate of the patient. In such a case, the ventricular electrode would also form part of the detection unit.

[0043] In an aspect, the present invention relates to a method for discriminating between an active phase and a resting phase of a human or animal patient. The method comprises the steps explained in the following.

[0044] 24.078P-WO / 27.11.2025 In a first step, at least two of the following four parameters of the patient carrying an implantable medical device in an implanted state are determined with a detection unit of the implantable medical device: i) an acceleration, ii) an impedance of a body structure (such as the thorax), iii) a body temperature, and iv) a cardiac rate.

[0045] Afterwards, the at least two determined parameters are compared with predeterminable thresholds. In this context, an individual predeterminable threshold is assigned to each parameter.

[0046] Subsequently, a physical state of the patient is classified either as a resting phase or as an active phase. In this context, the physical state of the patient is classified as resting phase if at least two of the following criteria are fulfilled: i) the determined acceleration lies below a first predeterminable threshold, ii) the determined impedance lies below a second predeterminable threshold, iii) the determined body temperature lies below a third predeterminable threshold, and iv) the determined cardiac rate lies below a fourth predeterminable threshold. If not at least two of these parameters are fulfilled, the physical state of the patient is classified as an active phase.

[0047] In an embodiment, the method comprises at least one further method step in which the implantable medical device performs a specific task that is only to be performed if the patient is in his or her resting phase. Examples of such tasks are explained above with respect to the implantable medical device and can be likewise applied to this method. These tasks comprise the activation of a unit, a functionality, or an algorithm of the implantable medical device, e.g., for activating a sleep apnea detection, for establishing a data communication, for performing routine measuring tasks, and / or for consolidating and / or compressing data.

[0048] In an embodiment, the method is a medical method that does not stop upon having classified the physical state of the patient as active phase or resting phase, but rather comprises at least one further diagnostic or therapeutic step such as applying a specific therapy to the patient if the patient is in his or her resting phase.

[0049] 24.078P-WO / 27.11.2025 All embodiments of the implantable medical device can be combined in any desired way and can be transferred either individually or in any arbitrary combination to the described methods. Likewise, all embodiments of each of the described methods can be combined in any desired way and can be transferred either individually or in any arbitrary combination to the implantable medical device and to the respective other method.

[0050] Further details of aspects of the present invention will be explained in the following making reference to exemplary embodiments and accompanying Figures. In the Figures:

[0051] Figure 1A schematically shows a cardiac stimulation assembly comprising an implantable medical device; and

[0052] Figure IB schematically shows different components of the implantable medical device of Figure 1 A.

[0053] Figure 1A shows a system comprising an implantable cardioverter-defibrillator (ICD) 1 as example of an implantable medical device for stimulating the human or animal heart. The system further comprises a programming device 2 serving as remote programming system. It is possible for the ICD device 1 to establish a wireless data communication with the programming device 2. The ICD device 1 and the programming device 2 together form a cardiac stimulation assembly 12.

[0054] The ICD device 1 comprises a housing 3 with a header 4 and a ventricular electrode 5 connected to the header 4. The ventricular electrode 5 comprises a tip electrode pole 6 and a ring electrode pole 7 that is proximally arranged from the tip electrode pole 6. Electric cardiac signals sensed between the tip electrode pole 6 and the ring electrode pole 7 are directly recorded within a heart chamber, typically the right ventricle. Thus, the first electrode 5 is designed and arranged to sense right ventricular electric signals.

[0055] Figure IB schematically illustrates individual components of the ICD device 1 that are comprised within the housing 3. In this and in all following Figures, similar elements will be denoted with the same numeral reference. The housing 3 houses a detection unit 31 (also

[0056] 24.078P-WO / 27.11.2025 referred to as sensing unit) that typically comprises an analog-to-digital converter, a bandpass filter, and an offset compensation. The detection unit 31 is operatively connected with a processor 32 that has access to a memory unit 33. The memory unit 33 serves for storing instructions for the processor 32 as well as data detected by the detection unit 31. The housing 3 further comprises an evaluation unit 34 that can also be part of the processor 32 and that serves for extracting features from the detected cardiac electric signal and optionally also from other detected parameters. The housing 3 further comprises a stimulation unit 35 that serves for stimulating the heart from which the detection unit 31 detects electric signals. The ventricular electrode 5 along with its tip electrode pole 6 and ring electrode pole 7 (confer Figure 1A) form part of the detection unit 31 and of the stimulation unit 35. Additionally, the housing 3 comprises a data communication unit 36 that serves for data transfer to the programming device 2 (confer Figure 1 A).

[0057] In addition to detecting cardiac electric signals for a subsequent determination of a cardiac rate of the patient, the detection unit 31 is able to determine at least one further parameter chosen from the group consisting of an acceleration, an impedance of a body structure, and a body temperature.

[0058] 24.078P-WO / 27.11.2025 List of reference numerals

[0059] 1 implantable medical device

[0060] 2 programming device

[0061] 12 cardiac stimulation assembly

[0062] 3 housing

[0063] 31 detection unit

[0064] 32 processor

[0065] 33 memory unit

[0066] 34 evaluation unit

[0067] 35 stimulation unit

[0068] 36 data communication unit

[0069] 4 header

[0070] 5 ventricular electrode

[0071] 6 tip electrode pole

[0072] 7 ring electrode pole

[0073] 24.078P-WO / 27.11.2025

Claims

Claims1. Implantable medical device (1) for discriminating between an active phase and a resting phase of a human or animal patient, comprising a processor (32), a memory unit (33), and a detection unit (31) configured to detect at least two of the following parameters of a patient carrying the implantable medical device (1) in an implanted state: i) an acceleration, ii) an impedance of a body structure, iii) a body temperature, and iv) a cardiac rate, characterized in that the memory unit (33) comprises a computer-readable program that causes the processor (32) to perform the following steps when being executed on the processor (32): a) determining, with the detection unit (31 ), at least two of the following parameters of a patient carrying the implantable medical device (1) in an implanted state: i) an acceleration, ii) an impedance of a body structure, iii) a body temperature, and iv) a cardiac rate; b) comparing the at least two determined parameters with predeterminable thresholds, wherein an individual predeterminable threshold is assigned to each parameter; and c) classifying a physical state of the patient as a resting phase if at least two of the following criteria are fulfilled: i) the determined acceleration lies below a first predeterminable threshold, ii) the determined impedance lies below a second predeterminable threshold, iii) the determined body temperature lies below a third predeterminable threshold, and iv) the determined cardiac rate lies below a fourth predeterminable threshold; otherwise classifying the physical state of the patient as an active phase.

2. Implantable medical device (1) according to claim 1, characterized in that the acceleration and the impedance of a body structure are determined as the at least two parameters.24.078P-WO / 27.11.20253. Implantable medical device (1) according to claim 1 or 2, characterized in that at least three of the parameters are determined in step a) and in that the physical state of the patient is classified as a resting phase if at least three of the criteria of step c) are fulfilled.

4. Implantable medical device (1) according to any of the preceding claims, characterized in that the computer-readable program causes the processor (32) to activate a unit, a functionality, and / or an algorithm of the implantable medical device (1) only if the physical state of the patient is classified as resting phase.

5. Implantable medical device (1) according to claim 4, characterized in that the unit, the functionality, and / or the algorithm has an average power consumption lying above a fifth predeterminable threshold.

6. Implantable medical device (1) according to claim 4 or 5, characterized in that the unit is a sleep apnea detection unit, in that the functionality is a sleep apnea detection and / or in that the algorithm is a sleep apnea detection algorithm.

7. Implantable medical device (1) according to claim 4 or 5, characterized in that the unit is a data communication unit, in that the functionality is a data communication ability and / or a signalization of a reception standby for a remote follow-up query and / or in that the algorithm is a data communication algorithm.

8. Implantable medical device (1) according to claim 4 or 5, characterized in that the functionality is an initiation of a routine measuring task and / or in that the algorithm is a routine measuring task algorithm.

9. Implantable medical device (1) according to claim 4 or 5, characterized in that the functionality is a consolidation and / or compression of data and / or in that the algorithm is a data consolidation and / or data compression algorithm.24.078P-WO / 27.11.202510. Implantable medical device (1) according to any of the preceding claims, characterized in that the computer-readable program causes the processor (32) to initiate a continuous measuring of a thoracic impedance of the patient for determining a breathing frequency of the patient upon having classified the physical state of the patient as resting phase.

11. Implantable medical device (1) according to claim 10, characterized in that the computer-readable program causes the processor (32) to at least transitionally stop the continuous measuring of the thoracic impedance upon having classified the physical state of the patient as active phase.

12. Implantable medical device (1) according to claim 11, characterized in that the computer-readable program causes the processor (32) to resume the continuous measuring of the thoracic impedance if the physical state of the patient is again classified as resting phase within a first predeterminable time period after having classified the physical state of the patient as active phase and otherwise to terminate the continuous measuring of the thoracic impedance.

13. Implantable medical device (1) according to any of the preceding claims, characterized in that the active phase is at least one of a sportive phase, a working phase, and a recovery phase, and in that the resting phase is a sleeping phase.

14. Implantable medical device (1) according to any of the preceding claims, characterized in that the implantable medical device (1) further comprises a stimulation unit (34) configured to stimulate the patient’s heart and a ventricular electrode (5) for providing stimulation pulses to a ventricle of the patient’s heart and optionally for detecting ventricular electric signals.

15. Method for discriminating between an active phase and a resting phase of a human or animal patient, the method comprising the following steps: a) determining, with a detection unit (31) of an implantable medical device (1), at least two of the following parameters of a patient carrying the implantable24.078P-WO / 27.11.2025medical device (1) in an implanted state: i) an acceleration, ii) an impedance of a body structure, iii) a body temperature, and iv) a cardiac rate; b) comparing the at least two determined parameters with predeterminable thresholds, wherein an individual predeterminable threshold is assigned to each parameter; and c) classifying a physical state of the patient as a resting phase if at least two of the following criteria are fulfilled: i) the determined acceleration lies below a first predeterminable threshold, ii) the determined impedance lies below a second predeterminable threshold, iii) the determined body temperature lies below a third predeterminable threshold, and iv) the determined cardiac rate lies below a fourth predeterminable threshold; otherwise classifying the physical state of the patient as an active phase.24.078P-WO / 27.11.2025

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