System for monitoring at least one parameter representative of decompensation of heart failure by means of a subcutaneous implant

Abstract

The present invention relates to a system for monitoring at least one parameter representative of a decompensation episode, the monitoring system comprising at least one subcutaneous implant (2), the subcutaneous implant (2) comprising at least an electrocardiograph and an accelerometer that are configured to collect information relating at least to the functioning of the heart of the living being, the monitoring system also comprising a computer server and a communication relay configured to allow at least the information collected by the subcutaneous implant (2) to be exchanged with the computer server, the computer server being configured to calculate changes in at least one parameter, from among haemodynamic and / or respiratory and / or electrophysiological parameters, on the basis of the data collected by at least the accelerometer and the electrocardiograph.

Description

[0001] DESCRIPTION

[0002] Title of the invention: System for monitoring at least one parameter representative of decompensation of heart failure by means of a subcutaneous implant.

[0003] The present invention relates to the field of medical devices and systems for monitoring the cardiac health of a living being. The present invention relates more particularly to a system for monitoring parameters characteristic of decompensation of heart failure in which an implantable medical device communicating with a computer server is intended to measure cardiac parameters.

[0004] Heart failure is a chronic condition affecting a large proportion of the population, particularly those over 60, and its frequency increases with age. Due to, among other things, the aging of the population, the frequency of heart failure will increase in the coming years by around 25% every four years.

[0005] Heart failure decompensation episodes are often accompanied by emergency hospitalization for patients suffering from this heart condition. Indeed, heart failure decompensation episodes often appear asymptomatic at the beginning and are not detected sufficiently early. As the heart failure decompensation episode progresses, the patient begins to experience the first symptoms of heart failure decompensation, such as fatigue, palpitations, or shortness of breath. With the onset of these symptoms, the patient is highly likely to be hospitalized urgently to stabilize their condition.

[0006] Heart failure decompensations can be detected before the onset of symptoms by a thorough analysis of various subclinical cardiac parameters, and more specifically hemodynamic parameters. Such detection of heart failure decompensation in the patient allows intervention by prescribing therapeutic treatment to stabilize the patient's cardiac function without requiring hospitalization.

[0007] The present invention falls within this context and proposes to provide a system for monitoring at least one parameter representative of an episode of decompensation of heart failure, which is in particular capable of providing information relating to the evolution of the cardiac function of a patient from one monitoring period to another. This information will enable a healthcare professional to evaluate the state of health of the patient and, based on this information, to decide whether or not to intervene. The monitoring system may, where appropriate, be provided with an algorithm intended to help the healthcare professional make decisions based on said information.

[0008] Thus, the main subject of the present invention is a system for monitoring at least one parameter representative of an episode of decompensation of heart failure in a living being, the monitoring system comprising at least one subcutaneous implant intended to be introduced under the skin of said living being, the subcutaneous implant comprising at least one electrocardiograph and an accelerometer configured to collect data relating at least to the functioning of the heart of the living being, the monitoring system also comprising a computer server and a communication relay configured to allow at least the exchange of data collected by the subcutaneous implant with the computer server, the computer server being configured to calculate changes in at least one parameter, among hemodynamic and / or respiratory and / or electrophysiological parameters, on the basis of the data collected by the accelerometer and the electrocardiograph,the subcutaneous implant comprising communication means configured to communicate data collected by at least the accelerometer and the electrocardiograph by means of a low-energy Bluetooth connection.,

[0009] The subcutaneous implant is a medical device implanted under the skin of a patient suffering from chronic heart failure, and implanted more particularly near the heart. This subcutaneous implant includes in particular an accelerometer and an electrocardiograph making it possible to collect data relating to the evolution of the patient's state of health, and in particular to define information representative of the evolution of these parameters by combining the data collected over several days, it being understood that the evolution of at least one parameter in unusual proportions may be indicative of an episode of decompensation.It is understood that the monitoring system is capable of monitoring the patient's state of health via the evolution of at least one parameter among hemodynamic parameters, respiratory parameters and electrophysiological parameters, so as to highlight early on the occurrence of an episode of decompensation of heart failure.

[0010] Indeed, by means of the data transmitted by the subcutaneous implant, the monitoring system, in particular via the computer server, is able to process information making it possible to monitor the evolution of various cardiac markers, both hemodynamic and electrophysiological, in particular the pre-ejection period, the amplitude of heart sounds, the width of the QRS complex, and / or the evolution of respiratory markers such as the respiratory rate. The monitoring system is thus able to transmit to appropriate medical personnel a plurality of information relating, in particular, to the evolution of cardiac function. This information allows a practitioner to monitor the evolution of the patient's heart failure and can make it possible to implement treatment as soon as cardiac decompensation appears, even before the patient presents the symptoms of this cardiac decompensation.

[0011] The means of communication allow the subcutaneous implant to communicate data relating to cardiac function and / or respiratory function to equipment located outside the patient's body, for example the communication relay and / or the computer server, while limiting the energy consumption of the subcutaneous implant. However, the issue of energy autonomy of subcutaneous implants is essential in this area, since it ensures in particular that the patient avoids surgical intervention for the replacement of the implant for as long as possible.

[0012] A Bluetooth low energy connection, known by the acronym BLE for "Bluetooth Low Energy", is used in various application areas, notably to transmit encryption keys between two elements that need to connect. In other words, this low energy connection has the advantage of being low energy, but only allows the transmission of small data, of the order of a few hundred bytes.

[0013] In the application of the invention, the BLE connection is also used to communicate data collected by the subcutaneous implant, which has a larger dimension. In particular, this data is data relating to a cardiac signal, collected by an accelerometer or an electrocardiogram, and it is of the order of several thousand bytes.

[0014] According to a characteristic of the invention, the communication means are configured to also communicate alerts relating to the availability of data collected by at least the accelerometer and the electrocardiograph, in communications separate from the data communications. It is understood that the problem of the size of the information transmitted via the BLE connection does not arise for the alerts, which consist of a message of only a few bytes.

[0015] According to a feature of the invention, a communication protocol for data communication between the subcutaneous implant and the communication relay and / or the computer server is configured so that the data communication from the implant is done in several successive sessions of sending partial data. The communication of the communication means of the subcutaneous implant with the communication relay and / or with the computer server by means of a low-energy Bluetooth connection makes it possible to limit the energy consumption of the subcutaneous implant and therefore to optimize the service life of the subcutaneous implant. Such a communication solution is particularly advantageous, in particular when it is implemented with a particular communication protocol, because communication by means of a low-energy Bluetooth connection only allows a small volume of data to be exchanged.Also, such a communication protocol allows the subcutaneous implant to both send alerts to the communication relay and transmit all the data collected by the subcutaneous implant, even though the volume of data is significant.

[0016] More particularly, each piece of data collected by the accelerometer and / or the electrocardiogram is divided into a plurality of partial data, the juxtaposition or combination of which forms said collected data, and the communication protocol implemented between the subcutaneous implant and the communication relay and / or the computer server consists of successively sending each of these partial data. It is understood that these partial data are of the order of a byte or a hundred bytes, a size suitable for the low-power communication implemented by the invention for the communication of data from the subcutaneous implant.

[0017] The data collected by the subcutaneous implant can thus be reconstructed by a juxtaposition of the partial data received successively by the communication relay and / or the computer server. According to a characteristic of the invention, the data collected by the subcutaneous implant is reconstructed by a combination of the partial data received successively by the communication relay and / or the computer server, the combination sequence being defined between the subcutaneous implant and the communication relay and / or the computer server. In other words, in particular for reasons of security of transfer of medical data, it is possible to configure the subcutaneous implant so that the communication of the data is encrypted, the data can only be correctly reconstructed if the combination sequence of the partial data is known to the communication relay and / or the computer server.This combination sequence may always be the same between this implant and the relay and / or the computer server, and thus not be revealed during the communication, or it may be changed at each data communication, one of the partial data sent containing information on the combination sequence. As mentioned, the communication protocol allows the subcutaneous implant to communicate the collected data via a plurality of successive partial data sending sessions, by means of a low-energy Bluetooth connection. The partial data are advantageously sent successively one after the other. According to a characteristic of the invention, the communication protocol is configured so that a partial data includes at least one information relating to the number of partial data forming said data communication.According to a characteristic of the invention, said partial data including the information relating to the number of partial data forming said data communication includes only this information. According to a characteristic of the invention, the partial data sent successively comprise said partial data including the information relating to the number of partial data forming said data communication as well as one or more other partial data comprising at least part of the data collected by the subcutaneous implant.

[0018] For example, if data collected by the subcutaneous implant is of the order of a thousand bytes and it is necessary to divide the data into “n” partial data to route the entire data via BLE connection, the communication protocol is configured so that “n +1” partial data are communicated, with a first partial data which includes the information according to which “n” partial data will follow, and the following “n” partial data which each includes a part of the collected data.

[0019] According to a feature of the invention, a communication protocol for the communication of data between the subcutaneous implant and the communication relay is different from a communication protocol for the exchange of data between the communication relay and the computer server.

[0020] When transferring data originally collected by the accelerometer or electrocardiograph of the subcutaneous implant, the communication protocol, and more particularly the number of interactions, implemented for communication between the subcutaneous implant and the communication relay is different from the communication protocol, and more particularly the number of interactions, implemented for communication between the communication relay and the computer server.

[0021] Low-power Bluetooth communication is implemented to limit the power consumption of the subcutaneous implant in order to increase its lifespan. This consideration is less important for the communication relay, which may include a more powerful external battery or be connected directly to a power network for its power supply. Also, the communication relay can communicate the information transmitted by the subcutaneous implant, for example, by means of a Wi-Fi connection allowing a larger volume of data to be exchanged than a low-power Bluetooth connection and over a greater distance.

[0022] In other words, according to a characteristic of the invention, the BLE connection is specific to the communication between the subcutaneous implant and the communication relay, the communication between the communication relay and the computer server being carried out via a high-speed communication network which allows, on the one hand, data to be communicated over a significant distance and, on the other hand, to ensure the transfer of data of significant dimensions.

[0023] For example, all the data collected by the subcutaneous implant for a given acquisition period is transferred from the subcutaneous implant to the communication relay in around ten successive coded messages while the same data is then sent to the computer server, from the communication relay, in a single message.

[0024] According to a characteristic of the invention, the subcutaneous implant comprises a temperature sensor configured to measure the body temperature of the living being. It is understood that the temperature sensor makes it possible to measure the body temperature of the patient in whom the subcutaneous implant is implanted. This temperature sensor makes it possible, in particular, to highlight an immune reaction, a probable sign of an infection and a precipitating factor in the decompensation of heart failure. Such an immune reaction is notably highlighted when the body temperature is above 38°C.

[0025] According to a characteristic of the invention, the subcutaneous implant comprises at least one housing on which are arranged at least a first electrode and a second electrode. These first and second electrodes make it possible to transmit data on the electrical functioning of the heart of the patient in whom the subcutaneous implant is implanted. The first and second electrodes are electrically conductive surfaces making it possible to collect an electrical signal. This electrical signal is transmitted to an electrocardiograph implanted on a printed circuit board. The electrocardiograph calculates the potential difference between the first and second electrodes to obtain electrophysiological data such as the heart rate and its variability, the width of the QRS complex, the duration of the QT segment.In addition, the data acquired by the electrocardiograph by calculating said potential difference can be coupled with data acquired by the accelerometer to obtain complementary data such as the pre-ejection period, namely the period between the electrical depolarization of a ventricle and the start of ventricular ejection. It should be noted that this pre-ejection period represents the period of contraction of the left ventricle for a constant volume of blood in the left ventricle at each contraction.

[0026] In addition, the first electrode and the second electrode can also be used to measure bioelectrical impedance values. Indeed, these electrodes are capable of emitting and receiving a low-intensity electrical current and an associated control module, here embedded on the printed circuit board housed in the housing, configured to measure the resistance of the biological tissues crossed by the current between a transmitting electrode and a receiving electrode. More specifically, this characteristic of the electrodes of emitting and receiving a low-intensity electrical current makes it possible to obtain data on the changes in blood volumes that occur during the cardiac cycle. It is understood that this data thus makes it possible to obtain data on the systolic time intervals.In addition, measuring bioelectrical impedance values ​​using these electrodes also provides data on respiratory parameters such as tidal volume. This tidal volume represents the patient's resting lung capacity during normal inspiration, i.e. when the patient is not making a particular effort, and provides information on the volume of air entering the lungs during inspiration. A decrease in this tidal volume can then indicate the presence of fluid in the lungs, a likely sign of an episode of heart failure decompensation.

[0027] According to a characteristic of the invention, the computer server is configured to calculate at least one evolution relating to the heart sounds and / or to a pre-ejection period and / or to a respiratory rate and / or to a heart rate using the data collected by the subcutaneous implant.

[0028] According to a characteristic of the invention, the accelerometer is capable of calculating linear accelerations along three orthogonal axes, the computer server being configured to calculate the changes in at least one hemodynamic and / or respiratory parameter on the basis in particular of data from the accelerometer relating to at least one of said axes.

[0029] According to an alternative characteristic of the invention, the accelerometer is a simple accelerometer, configured to detect linear acceleration along a single axis, the computer server being configured to calculate the changes in at least one hemodynamic and / or respiratory parameter on the basis in particular of data acquired on an axis by the accelerometer.

[0030] According to a feature of the invention, an algorithm is implemented on the computer server, said algorithm being configured to analyze the data acquired and transmitted by the subcutaneous implant so as to evaluate the risk of occurrence of an episode of decompensation of heart failure. The invention also relates to a communication method for a monitoring system as mentioned above, the communication method implementing:

[0031] - at least a first step during which the communication relay scans the surrounding space to detect the subcutaneous implant,

[0032] - at least one first additional step during which the subcutaneous implant generates a warning signal specifying that data relating to the functioning of the heart are capable of being exchanged with the computer server,

[0033] - at least a second step during which data or control instructions are exchanged between the subcutaneous implant and the computer server via the communication relay, the low-power wireless communication network implemented for communication between the subcutaneous implant and the communication relay being distinct from the high-speed wireless communication network implemented for communication between the communication relay and the computer server.

[0034] The communication relay is capable of scanning the surrounding area within a radius of approximately 5 meters around the communication relay for a signal emitted by the subcutaneous implant. Such a detection distance of the communication relay limits the possibility of foreign devices connecting to the communication relay.

[0035] According to a characteristic of the invention, the communication method implements at least a second auxiliary step occurring before the second step and during which the communication relay detects the subcutaneous implant and sends to the computer server a request for identification of the subcutaneous implant, the computer server processing said identification request by sending to the subcutaneous implant, via the communication relay, an encryption key specific to said subcutaneous implant and a data recovery request and / or a control instruction.

[0036] The computer server is understood to "process" the identification request insofar as the computer server is configured to, by means of the identification request, identify the subcutaneous implant and choose the action to be performed based on this identification of the subcutaneous implant. When the computer server has recognized the subcutaneous implant via the identification request, the computer server can thus decide that no action is necessary, for example that a data upload from the implant is not necessary, so that communication is not established between the implant and the computer server. Information to this effect can be sent to the implant via the communication relay.When the computer server has recognized the subcutaneous implant via the identification request, the computer server can decide that a return of data acquired by the implant is necessary or that the sending of new operating parameters to the implant is necessary. The computer server is then configured to transmit, in addition to the data retrieval instruction and / or the control instruction, a unique encryption key specific to the implant so that it can recognize that the communication is indeed coming from an authorized computer server and does not consist of an attempt to hack data.

[0037] The control instruction sent to the subcutaneous implant may contain instructions to change the operating parameters of the subcutaneous implant, for example the data acquisition frequency.

[0038] It should be noted that the identification request issued by the subcutaneous implant includes information that is specific to this subcutaneous implant. For example, the identification request may include the serial number of the subcutaneous implant and the MAC address of the BLE connection implemented by the subcutaneous implant. This identification request allows the computer server to recognize the subcutaneous implant that has been detected by the communication relay, and to adapt the sending of information to the subcutaneous implant, such as control instructions and / or a data retrieval request, depending on the subcutaneous implant that has been recognized.

[0039] In one version of the communication method, the data collected by the subcutaneous implant passes through the communication relay, i.e., this data is not stored in the communication relay. In other words, it is understood that the communication relay allows, in this version of the communication method, the data collected by the subcutaneous implant to pass between said subcutaneous implant and the computer server and that it does not process said data collected by the subcutaneous implant. This has an advantage in terms of data security since the communication relay does not have to be protected as effectively as, for example, the computer server.

[0040] According to a characteristic of the invention, the communication relay is configured to be able to temporarily store the data coming from the subcutaneous implant. In other words, in a standard operating mode, that is to say without malfunction of the communication network between the communication relay and the computer server and without malfunction of the BLE connection between the communication relay and the subcutaneous implant, the communication relay does not store the data, while in a degraded operating mode, with a potential or proven malfunction of the communication means, the communication relay temporarily stores the data until the communication means are restored.

[0041] It is understood that in this version of the communication method, the communication relay is able to retain the data collected by the subcutaneous implant in the event that the computer server is unavailable and therefore in the event that the transfer of information from the communication relay to the computer server is impossible. Such a version of the communication method makes it possible to ensure that the data collected by the subcutaneous implant is not lost in the event of unavailability of the computer server.

[0042] According to another characteristic of the invention, the communication relay is capable of temporarily retaining at least information transmitted by the computer server comprising a control instruction and an encryption key specific to a subcutaneous implant, allowing the communication relay to connect to this subcutaneous implant. By "temporarily", it is meant that the communication relay retains the information transmitted by the computer server until the next connection between the communication relay and the subcutaneous implant.

[0043] In this embodiment, it is understood that when the communication relay detects the presence of the subcutaneous implant and said subcutaneous implant signals that it has data to transmit, the communication relay is able to establish the connection with the subcutaneous implant without the intermediary of the computer server.

[0044] This version of the communication method has the advantage of being able to retrieve data collected by the subcutaneous implant or transmit control instructions to the subcutaneous implant, for example, when the computer server is unavailable, i.e. when the communication relay is unable to communicate with the computer server.

[0045] In this version of the communication method, the communication relay is able to store in particular an encryption key specific to the subcutaneous implant with which the relay must communicate, and it is understood that this communication relay comprises appropriate means for decrypting this encryption key and communicating it to the subcutaneous implant. In this context, at least the means for decrypting the encryption key are protected by encryption means. Such a version has the advantage of being able to recover the data collected by the subcutaneous implant independently of the operation of the computer server.

[0046] Furthermore, it should be noted that regardless of the version of the communication method that is implemented, the data collected by the subcutaneous implant and transmitted to the computer server and the information transmitted by the computer server to the subcutaneous implant are encrypted.

[0047] According to a characteristic of the invention, the communication between the communication relay and the subcutaneous implant is ensured by a low-energy Bluetooth connection and the communication between the communication relay and the computer server is ensured by a high-speed Internet connection. The Bluetooth connection makes it possible to use a minimum amount of energy stored in the subcutaneous implant, but in return involves multiplying the data transmissions between the subcutaneous implant and the communication relay so that the latter can recover all the data acquired by the subcutaneous implant.Depending on the role assigned to the communication relay, it can transmit directly to the computer server the data received from the subcutaneous implant, or the communication relay can concatenate the data received successively from the subcutaneous implant over a given period and send the concatenated data to the computer server in a single transmission.

[0048] According to a characteristic of the invention, the communication relay is intended to connect to a single subcutaneous implant, the communication relay being configured to continuously scan the surrounding space in search of said subcutaneous implant.

[0049] According to a characteristic of the invention, the communication relay is capable of detecting a plurality of subcutaneous implants, each subcutaneous implant being configured to allow or prohibit the connection of the communication relay to said subcutaneous implant depending on the recognition by said subcutaneous implant of an encryption key, said encryption key being specific and unique for each subcutaneous implant, said encryption key being communicated by the computer server to said subcutaneous implants via the communication relay.

[0050] It is understood that the encryption key is a security measure to ensure that the device wishing to connect to the subcutaneous implant is authorized by the monitoring system.

[0051] According to a feature of the invention, the subcutaneous implant can be configured to only accept to establish a connection with the communication relays for which it has in memory their identifier, for example the serial number and / or the mac address of the BLE connection. In another embodiment, the subcutaneous implant can be configured to accept attempts from any communication relay except those registered on a blacklist comprising the relays having attempted to connect a first time to the subcutaneous implant without authorization from the computer server, that is to say without the appropriate encryption key.

[0052] Other characteristics, details and advantages of the invention will emerge more clearly on reading the description which follows on the one hand, and on the other hand, examples of embodiment given for informational and non-limiting purposes with reference to the attached schematic drawings, in which:

[0053] [Fig.l] represents a general view of a subcutaneous implant according to one embodiment of the invention;

[0054] [Fig.2] very schematically represents the operation of a system for monitoring at least one parameter representative of an episode of decompensation of heart failure in a patient, said patient being equipped with a subcutaneous implant forming part of the monitoring system according to the invention;

[0055] [Fig.3] very schematically represents an embodiment of a communication method implemented within the surveillance system.

[0056] It should first be noted that while the figures set out the invention in detail for its implementation, these figures can of course be used to better define the invention, where appropriate. It should also be noted that these figures only set out examples of embodiments of the invention.

[0057] The features, variants and different embodiments of the invention may be combined with each other in various combinations, provided that they are not incompatible or mutually exclusive. In particular, variants of the invention may be conceived comprising only a selection of features described below in isolation from the other features described, if this selection of features is sufficient to confer a technical advantage or to differentiate the invention from the state of the art.

[0058] In the figures, elements common to several figures retain the same reference.

[0059] Figure 1 illustrates a medical device implantable in a living being and more particularly a subcutaneous implant 2 intended to be introduced under the skin of a living being who will be called hereinafter “patient”. This subcutaneous implant 2 is, in the embodiment shown, located under the skin of the patient in the thoracic region between the 4 ème intercostal space and the 5 ème intercostal space, at the level of the left edge of the sternum. Such positioning of the subcutaneous implant 1 makes it possible to obtain optimal measurements for both cardiac electrical parameters and cardiac mechanical parameters. It should be noted that in an alternative embodiment of the invention, the subcutaneous implant 1 may in particular be located on the 5 ème intercostal space, at the level of the anterior axillary line or on the 4 ème intercostal space at the midclavicular line.

[0060] As visible in Figure 1, the subcutaneous implant 2 extends in a direction of main longitudinal elongation, parallel to the axis L. More specifically, Figure 1 makes it possible to highlight a first face 4 of the subcutaneous implant 2.

[0061] The subcutaneous implant 2 comprises at a first longitudinal end 6 a first measuring end 8. This first measuring end 8 comprises a first electrode 10, here arranged on the first face 4. This first measuring end 8 is here formed, as an illustrative and non-limiting example of the invention, in a polymer product 12 such as an epoxy polymer, and the first electrode 10 is arranged on the surface within this polymer, which forms an electrically insulating environment around the first electrode 10.It is understood that this first electrode 10 is electrically connected to a printed circuit board present in the subcutaneous implant in order to be able to recover electrical potential information and / or to be able to emit a low intensity current, but that the polymer product ensures electrical insulation with respect to the rest of the metal parts of the implant, in particular with respect to a second electrode, which will be described in more detail in the description which follows. Such insulation of the first electrode 10 and the second electrode allows an electronic chip embedded in the subcutaneous implant 2 to measure a potential difference between these two electrodes and to form an electrocardiograph.The first measuring end may be made of another material provided that it allows the first electrode to be electrically insulated in accordance with what has just been mentioned and allows the subcutaneous implant 2 to be positioned under the patient's skin without risk to the patient. Alternatively, the first measuring end may be made of a metallic material like the rest of the subcutaneous implant, for example titanium, provided that an insulating coating, for example parylene, and an electrically insulating material extending across the thickness of the housing are provided around the first measuring end, exposing the first electrode.

[0062] Furthermore, this first measuring end 8 comprises an antenna, not shown here, capable of transmitting, as will be described in more detail in the description which follows, the information collected by the subcutaneous implant 2.

[0063] The subcutaneous implant 2 comprises an orifice 14 arranged at the first end 6 of the subcutaneous implant 2. This orifice 14 advantageously makes it possible to fix the subcutaneous implant 2 under the patient's skin by means of a tie. More precisely, this orifice 14 makes it possible to pass a tie, such as a wire, into the orifice which, in the embodiment shown, passes through the subcutaneous implant 2 from the first face 4 to a second face, opposite the first face and here not visible. The wire is then fixed to biological tissues of the patient to maintain the subcutaneous implant 2 as it was implanted.

[0064] The subcutaneous implant 2 comprises a second measuring end 18 at a second end 20 opposite the first end 6. This second measuring end 18 comprises a second electrode 22 participating, in combination with the first electrode 10 and an electronic chip as mentioned above, in forming an electrocardiograph.

[0065] It should be noted that for optimal operation of the subcutaneous implant 2, the implantation of the subcutaneous implant 2 is advantageously carried out in such a way that the first electrode 10 and the second electrode 22, and more broadly the first face 4, are opposite the patient's heart. Between the first end 6 and the second end 20, the subcutaneous implant 2 comprises a housing 24 comprising at least one printed circuit board, an accelerometer and the electronic chip to which the first electrode 10 and the second electrode 22 are electrically connected to form the electrocardiograph.

[0066] Advantageously, the housing 24 also includes a temperature sensor making it possible to highlight, for example, a potential infection of the patient increasing the risk of decompensation of heart failure.

[0067] The housing 24 comprises a first part in which is housed an electrical energy storage means sized to ensure appropriate autonomy for the subcutaneous implant and a second part in which are housed in particular the accelerometer and the chip of the electrocardiograph which have just been mentioned. In the illustrated example, each of these parts of the housing and the two ends on which the electrodes are arranged are formed by shells produced independently of each other and welded to each other in a second step. Alternatively, some of the parts between the parts of the housing and the measuring ends can be produced in a single piece. For example, in an alternative embodiment of the invention, not shown here, the housing can be formed in a single piece from the first end to the second end and configured to house the battery and the printed circuit board.

[0068] In each of these cases, the first electrode 10 and the second electrode 22 are advantageously arranged at opposite ends of the subcutaneous implant.

[0069] The housing, without this being limiting of the invention, can be formed from titanium and electrical insulation means are implemented so as to electrically insulate the electrodes 10, 22 integrated into the housing 24 on either side of the housing from each other.

[0070] In other words, the electrical insulation means ensure that there are no conductive elements connecting the first electrode 10 and the second electrode 22.

[0071] It should be noted that without departing from the context of the invention, the first electrode and the second electrode may be insulated from each other by a different insulating material, preferably polymer, provided that the latter does not present any risk to the health of the patient in whom the subcutaneous implant 2 is implanted.

[0072] Furthermore, the subcutaneous implant 2 comprises, as mentioned previously, the electrical energy storage means housed in the housing 24. This electrical energy storage means may be a primary battery, such as an electric cell, or a rechargeable accumulator battery. The electrical energy storage means is intended to supply electrical energy to the various components of the subcutaneous implant 2, and particularly the printed circuit board.

[0073] As mentioned previously, at least one accelerometer, an electronic chip of an electrocardiograph and a temperature sensor are housed in the housing 24, the electrodes of the electrocardiograph being arranged on the housing 24.

[0074] The accelerometer may in one embodiment be a three-axis accelerometer, capable of detecting linear accelerations along a longitudinal axis, a transverse axis and a sagittal axis. An average acceleration value may be calculated by normalizing the three values ​​detected respectively on one of the axes. In an alternative embodiment of the invention, the accelerometer may be a simple accelerometer, configured to detect linear acceleration along a single axis.

[0075] The data obtained by the accelerometer make it possible in particular to analyze the patient's hemodynamic and respiratory parameters as well as information relating to the patient's posture at the time the information is taken by the subcutaneous implant 2, namely, for example, whether the patient is standing or lying down with an estimation of the angle of inclination of the patient's lying position. Indeed, during an episode of decompensation of heart failure, the patient experiences breathing difficulties when in a lying position with zero inclination, i.e. flat. To overcome this difficulty, the patient gradually straightens his torso using additional pillows, the change in inclination being able to be detected by the accelerometer.It is understood that this information relating to the patient's inclination, particularly during sleep, allows a practitioner to determine, by cross-referencing this information with different markers where appropriate, whether or not intervention is necessary.

[0076] As mentioned previously, the subcutaneous implant 2 is equipped with an electrocardiograph comprising the electronic chip located on the printed circuit board and first and second electrodes 10 and 22 arranged on the housing 24. The combination of the electrocardiograph with the three-axis accelerometer advantageously makes it possible to facilitate the analysis of the data from the latter, in particular for the analysis of heart sounds or the pre-ejection period commonly called “PEP”.

[0077] The temperature sensor is used to measure the patient's temperature. This temperature sensor provides more stable information about the patient's temperature than an external temperature measurement. This information about the patient's temperature can highlight a possible immune reaction from the patient, a sign of a potential infection. Indeed, during an infectious episode, the patient is more exposed to the risk of cardiac decompensation. It is understood that this data relating to the patient's temperature allows the practitioner in charge of monitoring the patient to be more vigilant regarding the signals from the three-axis accelerometer and the electrocardiograph.

[0078] The operation of these devices embedded in the subcutaneous implant, i.e. the electrocardiograph, the accelerometer and the temperature sensor, is advantageously controlled by the printed circuit board, and more precisely by a microcontroller. It is understood that the microcontroller is capable of activating the devices embedded in the subcutaneous implant to carry out, for example, data acquisitions according to a pre-established frequency. It should be noted that the printed circuit board is, when the subcutaneous implant 2 is assembled, embedded, by way of non-limiting examples, in resin or silicone. It is understood that this resin or silicone allows a rigid connection between the accelerometer and the housing, so that all of the movements perceived by the accelerometer are representative of the body movements involving the displacement of the subcutaneous implant and can therefore be used for signal processing by the monitoring system.

[0079] The measurement frequency is set by a control system located on a remote computer server. This frequency can be changed over time to accommodate the measurements needed to monitor the patient's condition.

[0080] More specifically, the measurement frequency of the subcutaneous implant 2 is in a nominal usage mode of one data acquisition per day. However, the practitioner in charge of the patient can modify the number of daily acquisitions to more precisely monitor disturbances or changes in the patient's condition during the day. Alternatively, the practitioner can choose to reduce the number of daily data acquisitions that is carried out by the subcutaneous implant 2 when, for example, the patient's health condition is stable.

[0081] It is understood that the number of daily data acquisitions carried out by the subcutaneous implant 2 can be modulated by the practitioner according to needs. It should be noted that in the case of a single data acquisition per day, this acquisition is advantageously carried out at night while the patient is asleep. Thus, the data collected by the subcutaneous implant 2 are not disturbed, for example, by physical activity such as climbing stairs. More specifically, the data acquisition by the subcutaneous implant 2 is advantageously carried out at a fixed time at night when the patient is in a stable state that can be repeated day after day.

[0082] Furthermore, the subcutaneous implant 2 performs data acquisition over a time interval of approximately 30 seconds. Such a data acquisition duration allows the subcutaneous implant 2 to be able to acquire data over a number of cycles, cardiac or respiratory, sufficiently large to ensure obtaining information allowing a practitioner to analyze the risk of decompensation of heart failure accurately. The duration of the data acquisition performed by the subcutaneous implant 2 may be longer, for example of the order of 2 minutes, to improve the accuracy of the information collected. It should be noted that the duration of the data acquisition may be modulated by the practitioner according to the accuracy of the information he needs. In addition, the duration of the data acquisition performed by the subcutaneous implant 2 may be greater than 2 minutes depending on the amount of data that can be stored in the subcutaneous implant 2.

[0083] In addition, the printed circuit board comprises communication means allowing the subcutaneous implant 2 to transmit and / or receive information by means of the previously mentioned antenna. More specifically, these communication means are wireless communication means using the Bluetooth® telecommunications standard, and more precisely the Bluetooth low energy protocol, better known by the English acronym “BLE” for Bluetooth Low Energy.

[0084] This subcutaneous implant 2 is, as mentioned above, intended to collect data autonomously, that is to say without patient intervention, this data being processed and stored in a computer server communicating with the subcutaneous implant to give a practitioner information on the evolution of such or such parameter over the acquisition periods. It is the analysis of the evolution of at least one parameter representative of cardiac decompensation which allows the practitioner to evaluate the risk of decompensation of heart failure occurring in the patient in whom the subcutaneous implant 2 has been implanted. It should be noted that in the embodiment shown, in particular the embodiment of FIG. 2 which will be described later, the subcutaneous implant 2 is implanted in a patient suffering from chronic heart failure.Of course, in an alternative embodiment of the invention, the subcutaneous implant 2 can be implanted in a healthy patient not presenting heart failure, the subcutaneous implant 2 being able in this case to detect the onset of heart failure.

[0085] The computer server is configured to provide the practitioner, such as a doctor in charge of the patient, with changes in the parameters determined from the data collected and transmitted by the subcutaneous implant 2. The practitioner can in particular analyze the changes in the heart sounds, the changes in the duration of the pre-ejection period "PEP", the changes in the respiratory rate, and / or, without this being limiting of the invention, the changes in the patient's inclination during sleep. The computer server can be configured to communicate all of the information in its possession, that is to say all of the changes in parameters that it has been able to calculate on the basis of all of the data acquired by the subcutaneous implant. The accumulation of cardiac and / or respiratory markers, the changes in which are assimilated to a deterioration, allows the practitioner to highlight the risk of occurrence of an episode of cardiac decompensation.

[0086] Alternatively, the computer server may be configured, particularly when the patient's state of health has been declared stable, to only communicate to the practitioner information on the evolution of a particular parameter, and particularly on the evolution of the markers which are known to be the first to deteriorate in the event of cardiac decompensation, such as the evolution of the amplitude of the heart sounds and the evolution of the duration of the pre-ejection period. In other words, the computer server may be configured to select the information sent to the practitioner, and to only send information on the evolution of other parameters when it has been judged that the evolution of the early markers is deemed indicative of the possible onset of an episode of cardiac decompensation which is likely to occur.

[0087] For example, the amplitude of heart sounds can be analyzed based on accelerometric signal processing. This signal processing is advantageously done remotely, on the computer server, once the latter has retrieved all the data collected by the subcutaneous implant over a given acquisition period. The signal processing can consist of dividing the accelerometric signal into time cycles, each time cycle being analyzed to identify characteristic segments of the heart sound, known as segments S1, S2, S3. An average of the amplitude of the segments identified in each time cycle is performed so that three heart sound values ​​are calculated for each acquisition period. The computer server is configured to, by comparing these average heart sound values ​​from one acquisition period to another, define a change in the amplitude of the heart sounds.The practitioner can thus receive, on an appropriate display means, information relating to an increasing or decreasing evolution of a particular heart sound SI, S2, S3. For example, an increase in the SI sound over time and / or a decrease in the S3 sound over time can be an indicator of cardiac decompensation.

[0088] Furthermore, one of the markers whose evolution is analyzed, in addition to those just mentioned, may be the respiratory rate. Indeed, during an episode of decompensation of heart failure, the lung can fill with fluid. The tidal volume used by the patient with each breath is then lower so that the patient naturally compensates for this decrease in the volume of air used during normal breathing by increasing their respiratory rate.

[0089] Another of these markers may be the patient's inclination during sleep. Indeed, it is known that during an episode of decompensation, the patient experiences breathing difficulties that they overcome by slightly raising their upper body during sleep, so analyzing the evolution of the patient's inclination during sleep is rich in information.

[0090] The cross-analysis of these different parameters allows the practitioner to define with great precision the risk of decompensation of heart failure in the patient and to intervene before resorting to hospitalization of the patient.

[0091] Figure 2 represents a monitoring system 30 for an episode of decompensation of heart failure. Within this monitoring system 30, the subcutaneous implant 2 is intended to collect measurements relating to the functioning of the heart of a patient 32 in whom the subcutaneous implant 2 is implanted.

[0092] Furthermore, the subcutaneous implant 1 is configured to communicate with a communication relay 34 such that the information containing the various measurements collected by the subcutaneous implant 2 can be transmitted from the subcutaneous implant 2 to the communication relay 34. This communication relay 34 is an electronic box located outside the patient's body or a mobile application present on a mobile device such as a smartphone or tablet. The subcutaneous implant 2 communicates by means of a low-energy Bluetooth® connection 36 with the communication relay 34 by sending messages whose quantity of data is limited, of the order of 241 bytes. The communication between the communication relay 34 and the subcutaneous implant 2 can thus be carried out by a plurality of messages each comprising a part of all the information collected by the subcutaneous implant 2.Security measures are implemented to ensure the consistency and confidentiality of all information collected by the subcutaneous implant 2.

[0093] More specifically, the subcutaneous implant 2 is capable of generating a signal or an alert to enable its detection by the communication relay 34. It should be noted that this step of detecting the subcutaneous implant 2 will be described in more detail in the description which follows. Once the subcutaneous implant 2 has been detected by the communication relay 34 and connected to the latter, the subcutaneous implant 2 is capable of implementing a specific communication protocol via communication means to enable it to communicate, via a low-power connection, all of the data collected by the equipment embedded in the subcutaneous implant 2.

[0094] This communication protocol is specific to the subcutaneous implant 2 and the communication means of the subcutaneous implant 2. In particular, the implementation of a low-power BLE connection for the communication of medical data involves here dividing into “n” partial data the data collected by the accelerometer and / or the electrocardiogram, which takes the form of a signal over a given time cycle and which therefore takes a size of one or several thousand bytes.

[0095] The communication protocol may in particular be configured so that the subcutaneous implant 2 sends, when data must be communicated to the communication relay in particular, a first message, or a first partial data item, comprising specific information relating to the number of messages, or partial data, that the subcutaneous implant 2 will emit to transmit all of the collected data. This first message initiates a transmission sequence comprising as many messages as necessary for the subcutaneous implant 2 to be able to transmit all of the collected data. It should be noted that the communication of all of the data collected by the subcutaneous implant 2 into a plurality of messages, or partial data, requires a prior step of fragmenting the information collected by the subcutaneous implant 2 into a plurality of these partial data items.It should also be noted that the communication relay and / or the computer server is also configured to be able to reconstruct the data from the partial data, either by juxtaposing them in the order of reception, or by combining them according to a combination sequence specific to this data communication.

[0096] The transfer of data by the low energy Bluetooth protocol requires a relative proximity between the subcutaneous implant 2 located in the body of the patient 32 and the communication relay 34 located outside the body of the patient 32. For this purpose, the communication relay 34 can advantageously be arranged, for example, in the room of the patient 32 wearing the subcutaneous implant 2 so that the exchange of data can take place during the night when the patient 32 is located near the communication relay 34.

[0097] The communication relay 34 is configured to also communicate with a computer server 38. At this computer server 38 the information collected by the subcutaneous implant 2 is processed. More specifically, within the computer server 38 the information collected by the subcutaneous implant 2 is analyzed so as to define, for example, an amplitude of heart sounds.

[0098] According to the invention, the subcutaneous implant 2 is capable of transmitting to the computer server 38, by means of the low-energy Bluetooth connection 36 and the communication relay 34, data relating to the electrical functioning of the patient's heart 32, this data being acquired via the electrocardiograph, the accelerometer, and where appropriate the temperature sensor. This information can be read, directly or after appropriate signal processing, by a practitioner who can thus have, in order to carry out a diagnosis of possible cardiac decompensation, information relating to the heart sounds SI, S2 and S3 in connection with systole and diastole, the heart rate, the variability of the heart rate, the width of the T1 complex

[0099] QRS, QT segment duration, heart rate and pre-ejection period. It is understood that some of these data are advantageously deduced from the cross-referencing of information from the three-axis accelerometer and the electrocardiograph.

[0100] It should be noted that the information relating to the evolution of the parameter representative of cardiac decompensation, as calculated and stored on the computer server 38, is communicated to the practitioner by information display means which may consist of a computer screen of the practitioner, the computer being connected to the server remotely via an Internet connection, or else a mobile communication device, such as a smartphone or tablet. It is understood that the computer server 38 is advantageously delocalized, that is to say hosted remotely, to be able to be accessible by a multitude of practitioners as long as they have secure access to be able to retrieve the data which concerns their patients and only their patients.Alternatively, without the operation previously mentioned being modified, the computer server 38 can be considered as being the computer or mobile communication device of the practitioner, this computer or telecommunications equipment then comprising software capable of carrying out the actions previously mentioned in relation to the computer server.

[0101] Information transmitted on the computer display medium or by mobile telecommunication means may be transmitted in its entirety without prior processing or with a selection of the information to be provided to the practitioner. This selection may, for example, limit the transmission of sensitive data depending on the type of display medium used.

[0102] It should be noted that additionally, the computer server 38 may comprise an algorithm capable of carrying out an initial analysis of the data collected by the subcutaneous implant 2 and of generating an alert for the practitioner if the information resulting from the processing of this data indicates a development deemed characteristic of a risk of cardiac decompensation.

[0103] The control system operating on the computer server 38 ensures the recognition and validation of the subcutaneous implant 2. The computer server 38 can communicate, via the communication relay 34, with the subcutaneous implant 2 so as to modify the acquisition frequency and / or the time range of these acquisitions and / or the type of data to be collected. For example, the computer server can generate a specific data retrieval request directed at the subcutaneous implant 2 or to only carry out a temperature acquisition, either immediately after receiving the specific data retrieval request, or during the next scheduled acquisition session.

[0104] Communication between the communication relay 34 and the computer server 38 is, in the embodiment shown, ensured by a secure internet connection 40. More specifically, this internet connection 40 is a Wi-Fi connection. It is understood that the exchange of information between the communication relay 34 and the computer server 38 is dependent on the internet connection 40.

[0105] It should be noted that in an alternative embodiment of the invention, it is possible for the computer server 38 to transmit data to the communication relay 34. This communication relay 34 can temporarily store the data transmitted by the computer server 38 until it establishes communication with the subcutaneous implant 2 and transmits said information to it. This information may, for example, include changes to the frequency of data acquisition by the subcutaneous implant 2. Alternatively, the communication relay 34 can store the information transmitted by the subcutaneous implant 2, for example, in the event that the computer server 38 is unavailable. This information stored by the communication relay 34 will then be transmitted to the computer server 38 when it is available again.

[0106] The communication relay 34 is capable of detecting all of the subcutaneous implants 2 in a surrounding space of approximately 5 meters. However, in order for the communication relay 34 to be able to connect to one of the subcutaneous implants 2, the communication relay 34 must provide this implant with an encryption key transmitted by the computer server 38. This encryption key is specific to each subcutaneous implant 2. It should be noted that the communication relay does not necessarily have knowledge of the key, depending on the communication mode implemented, but it is able to present it to the subcutaneous implant.

[0107] In this context of communication to be established between a subcutaneous implant and a communication relay, the subcutaneous implant 2 can be configured to keep in memory the communication relay(s) 34 to which it can connect and / or to blacklist all devices having attempted to connect without authorization from the computer server 38.

[0108] In a particular secure operation, the subcutaneous implant can be configured to be able to connect to a single communication relay 34. This subcutaneous implant 2 is then associated only with said communication relay 34.

[0109] If a communication relay 34 is configured to be able to connect to several subcutaneous implants 2 and serve as a relay between each of these implants and the computer server, for example when several people in the same household are equipped with a subcutaneous implant of a monitoring system in accordance with what has been described previously, it is understood that the communication relay communicates with a single subcutaneous implant at a time, using the encryption key specific to each subcutaneous implant as it was provided by the computer server 38 at the time of the acquisition period defined for this subcutaneous implant.

[0110] The monitoring system 30 notably allows the implementation of a communication method 42 specific to the invention during which, in a succession of steps, the computer server 38 is allowed to receive the desired information from the subcutaneous implant 2.

[0111] This communication method 42 is more particularly visible in Figure 3. As visible in this Figure 3, the communication method 42 implements a first step 44 during which the communication relay 34 scans the surrounding space in search of the subcutaneous implant 2. It is understood more specifically that the communication relay 34 is positioned in a fixed manner outside the body of the patient 32 and is continually searching for a signal emitted by the subcutaneous implant 2.

[0112] During a first additional step 46, the subcutaneous implant 2 generates a warning signal allowing the communication relay 34 to detect the subcutaneous implant 2 and specifying that physiological data are capable of being exchanged with the computer server 38. It should be noted that the subcutaneous implant 2 generates a signal at regular intervals, to allow the detection of the subcutaneous implant 2 by the communication relay 34 when the subcutaneous implant 2 is in proximity to the communication relay 34. The duration of the signal transmission interval is configurable, and may for example be of the order of 5 minutes or 20 minutes. This signal may include, like the signal transmitted during the first additional step 46, an indicator allowing the communication relay 34 to become aware that data are available and may be exchanged by the subcutaneous implant 2.This signal may also not include an indicator, in which case, the communication relay 34 may nevertheless connect to the subcutaneous implant 2 if, for example, the computer server 38 has transmitted information to the communication relay 34 intended for the subcutaneous implant 2.

[0113] Indeed, the activation of Bluetooth and the emission of signals from said subcutaneous implant 2 results in energy consumption. To increase the longevity of the energy storage means of the subcutaneous implant 2, the latter connects to the communication relay 34 only, on the one hand when the subcutaneous implant 2 includes information to be transmitted to the computer server 38 via the communication relay 34, and on the other hand when the communication relay 34 holds information emanating from the computer server 38 and intended for the subcutaneous implant 2.

[0114] The communication method 42 implements a second auxiliary step 48 which occurs, in the embodiment shown, when the communication relay 34 has detected the subcutaneous implant 2 and the latter has emitted an indicator indicating that one or more measurement information items are capable of being recovered by the computer server 38. During this second auxiliary step 48, the communication relay 34 detects the subcutaneous implant 2 and the computer server 38 generates a communication protocol comprising information allowing the communication relay 34 to connect to the subcutaneous implant 2.

[0115] It is understood from this second auxiliary step 48 that the connection between the subcutaneous implant 2 and the communication relay 34 is governed by the computer server 38. Furthermore, the communication protocol emitted by the computer server 38 makes it possible to limit the connections of the subcutaneous implant 2 to the communication relay 34 strictly when the subcutaneous implant 2 holds information that the computer server 38 requires, or when the communication relay 34 holds information intended for the subcutaneous implant 2.

[0116] The communication method 30 implements a second additional step 50 occurring before the second auxiliary step 48 during which the communication relay 34 transmits to the computer server 38 information relating to the detection of the subcutaneous implant 2. It is understood that this step of the communication method 30 is part of the process of controlling the connection of the subcutaneous implant 2 to the communication relay 34 by the computer server 38. Indeed, the transmission of this detection signal by the communication relay 34 makes it possible to generate a request from the computer server 38 relating to the connection or absence of connection between the communication relay 34 and the subcutaneous implant 2.

[0117] The authorization of the connection between the communication relay 34 and the subcutaneous implant 2 by the computer server 38 makes it possible, in the embodiment shown, to implement a second step 52 of the communication method 30. During this second step 52 of the communication method 30, the subcutaneous implant 2 exchanges information with the computer server 38 via the communication relay 34. It should be noted that alternatively the exchange of information between the computer server 38 and the subcutaneous implant 2 can take place from the computer server 38 to the subcutaneous implant 2. Such an exchange in this sense makes it possible, as mentioned previously, to be able to remotely configure the subcutaneous implant 2. The present invention achieves the goal it set for itself by proposing a system for monitoring at least one parameter representative of an episode of decompensation of heart failure.This detection of said episode of cardiac decompensation is carried out by cross-referencing information obtained by a subcutaneous implant implanted in the patient. The subcutaneous implant communicates its data with a computer server by means of a communication relay which carries out the transition of the message with the computer server.

Claims

CLAIMS 1. Monitoring system (30) of at least one parameter representative of an episode of decompensation of heart failure in a living being, the monitoring system (30) comprising at least one subcutaneous implant (2) intended to be introduced under the skin of said living being, the subcutaneous implant (2) comprising at least one electrocardiograph and an accelerometer configured to collect data relating at least to the functioning of the heart of the living being, the monitoring system (30) also comprising a computer server (38) and a communication relay (34) configured to allow at least the exchange of data collected by the subcutaneous implant (2) with the computer server (38), the computer server (38) being configured to calculate changes in at least one parameter, among hemodynamic and / or respiratory and / or electrophysiological parameters, on the basis of the data collected by at least the accelerometer and the electrocardiograph,the subcutaneous implant (2) comprising communication means configured to communicate data collected by at least the accelerometer and the electrocardiograph by means of a low-energy Bluetooth connection (36)., 2. Monitoring system (30) according to claim 1, wherein the communication means are configured to further communicate alerts relating to the availability of data collected by at least the accelerometer and the electrocardiograph, in communications separate from the data communications.

3. Monitoring system (30) according to claim 1 or 2, wherein a communication protocol for data communication between the subcutaneous implant (2) and the communication relay (34) and / or the computer server (38) is configured such that data communication from the subcutaneous implant (2) to the communication relay (34) takes place in several successive data sending sessions.

4. Monitoring system (30) according to one of claims 1 to 3, wherein a communication protocol for the communication of data between the subcutaneous implant (4) and the communication relay (34) is different from a communication protocol for the exchange of data between the communication relay (34) and the computer server (38).

5. Monitoring system (30) according to one of claims 1 to 4, wherein the subcutaneous implant (2) comprises a temperature sensor configured to measure the body temperature of said living being.

6. Monitoring system (30) according to any one of claims 1 to 5, wherein the subcutaneous implant (2) comprises at least one housing (24) on which are arranged at least one first electrode (10) and one second electrode (22).

7. Monitoring system (30) according to any one of claims 1 to 6, wherein the computer server (38) is configured to calculate at least one evolution relating to the heart sounds and / or to a pre-ejection period and / or to a respiratory rate and / or to a heart rate by means of the data collected by the subcutaneous implant (2).

8. Monitoring system (30) according to any one of claims 1 to 7, in which the accelerometer is capable of calculating linear accelerations along three orthogonal axes, the computer server (38) being configured to calculate the changes in at least one hemodynamic and / or respiratory parameter on the basis in particular of data from the accelerometer relating to at least one of said axes.

9. Monitoring system (30) according to any one of claims 1 to 8, wherein an algorithm is implemented on the computer server, said algorithm being configured to analyze the data acquired and transmitted by the subcutaneous implant (2) so as to assess the risk of occurrence of an episode of decompensation of heart failure.

10. Communication method (42) for a monitoring system (30) according to any one of claims 1 to 9, the communication method (42) implementing: - at least a first step (44) during which the communication relay (34) scans the surrounding space to detect the subcutaneous implant (2), - at least one first additional step (46) during which the subcutaneous implant (2) generates a warning signal specifying that data relating to the functioning of the heart are capable of being exchanged with the computer server (38), - at least a second step (52) during which data or control instructions are exchanged between the subcutaneous implant (2) and the computer server (38) via the communication relay (34), the low-power wireless communication network implemented for communication between the subcutaneous implant and the communication relay being distinct from the high-speed wireless communication network implemented for communication between the communication relay and the computer server.

11. Communication method according to claim 10, wherein the communication method implements at least one second auxiliary step (48) occurring before the second step (52) and during which the communication relay (34) detects the subcutaneous implant (2) and sends to the computer server (38) a request for identification of the subcutaneous implant (2), the computer server (38) processing said identification request by sending to the subcutaneous implant (2), via the communication relay, an encryption key specific to said subcutaneous implant and a data recovery request and / or a control instruction.

12. Communication method according to any one of claims 10 and 11, wherein the communication between the communication relay (34) and the implant subcutaneous (2) is provided by a low-energy Bluetooth connection (36) and communication between the communication relay and the computer server is provided by a high-speed Internet connection.

13. Communication method according to any one of claims 10 to 12, wherein the communication relay (34) is intended to connect to a single subcutaneous implant (2), the communication relay (34) being configured to continuously scan the surrounding space in search of said subcutaneous implant (2).

14. Communication method according to any one of claims 10 to 12, wherein the communication relay (34) is capable of detecting a plurality of subcutaneous implants (2), each subcutaneous implant (2) being configured to allow or prohibit the connection of the communication relay (34) to said subcutaneous implant (2) depending on the recognition by said subcutaneous implant (2) of an encryption key, said encryption key being unique to each subcutaneous implant (2), said encryption key being communicated by the computer server (38) to said subcutaneous implants (2) via the communication relay (34).

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