System for monitoring at least one parameter indicative of heart failure decompensation by means of a subcutaneous implant - Patent Application 20070122999

Abstract

SYSTEM FOR MONITORING CARDIAC FAILURE DECOMPENSATION BY A SUBCUTANEOUS IMPLANT: The present invention relates to a system for monitoring at least one parameter indicative of the onset of decompensation, the monitoring system comprising at least one subcutaneous implant (2), the subcutaneous implant (2) comprising at least one electrocardiograph and at least one accelerometer configured to collect information on the functioning of the heart of a living organism, the monitoring system also comprising a computer server and a communication relay configured to enable the exchange of information collected by the subcutaneous implant (2) with the at least computer server, the computer server being configured to calculate a change in at least one parameter from among hemodynamic and / or respiratory and / or electrophysiological parameters based on data collected by at least the accelerometer and the electrocardiograph.

Description

[Technical Field]

[0001] The present invention relates to the field of medical devices and systems for monitoring cardiac health in living organisms, and more particularly to a system for monitoring parameters characteristic of heart failure decompensation, in which an implantable medical device in communication with a computer server is configured to measure the cardiac parameters. [Background technology]

[0002] Heart failure is a chronic condition that affects a large portion of the population, particularly those over 60, and its frequency increases with the age of the patient. As the population ages, the incidence of heart failure is set to increase by approximately 25% every four years.

[0003] The onset of heart failure decompensation often requires emergency hospitalization of patients suffering from this cardiac condition. In fact, the onset of heart failure decompensation often appears asymptomatic at the time of onset and is not detected early enough. As the onset of heart failure decompensation progresses, patients begin to experience the first symptoms of heart failure decompensation, namely fatigue, palpitations, and shortness of breath. When these symptoms appear, emergency hospitalization is likely required to stabilize the patient's condition.

[0004] Heart failure decompensation can be detected before symptoms appear by detailed analysis of various subclinical cardiac parameters, particularly hemodynamic parameters. Detecting heart failure decompensation in a patient in this manner makes it possible to treat the patient by prescribing therapeutic treatments that stabilize the patient's cardiac function without the need for hospitalization. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention is part of this context and aims to provide a system for monitoring at least one parameter indicative of the onset of heart failure decompensation, which is capable in particular of providing information on the changes in a patient's cardiac function from one monitoring period to the next. This information allows a healthcare professional to assess the patient's health status and, based on this information, decide whether an intervention is necessary. Where appropriate, the monitoring system may comprise algorithms configured to help the healthcare professional make a decision based on said information. [Means for solving the problem]

[0006] Therefore, the main object of the present invention is a system for monitoring at least one parameter indicative of the onset of heart failure decompensation in a living organism, the monitoring system comprising at least one subcutaneous implant configured to be introduced under the skin of said living organism, the subcutaneous implant comprising at least one electrocardiograph and one accelerometer configured to collect data related to at least the function of the heart of the living organism, the monitoring system also comprising a computer server and a communication repeater configured to enable 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 of the following parameters: hemodynamic and / or respiratory and / or electrophysiological parameters based on the data collected by the accelerometer and the electrocardiograph, the subcutaneous implant comprising communication means configured to communicate the data collected by at least the accelerometer and the electrocardiograph by means of a low energy Bluetooth connection.

[0007] The subcutaneous implant is a medical device that is implanted subcutaneously in a patient suffering from chronic heart failure, more specifically, near the heart. In particular, the subcutaneous implant includes an accelerometer and an electrocardiograph that allow for the collection of data on changes in the patient's health, particularly by combining data collected over several days to define information representative of changes in these parameters, whereby an abnormal rate of change in at least one parameter may indicate the onset of decompensation. The monitoring system can monitor the patient's health through changes in at least one parameter from among hemodynamic, respiratory, and electrophysiological parameters to provide early evidence of the onset of heart failure decompensation.

[0008] Using the data transmitted by the subcutaneous implant, the monitoring system, particularly via a computer server, can process information that allows it to monitor changes in various cardiac markers, both hemodynamic and electrophysiological, particularly changes in respiratory markers such as pre-ejection period, heart sound amplitude, QRS complex width, and / or respiratory frequency. Thus, the monitoring system can transmit multiple pieces of information, particularly regarding changes in cardiac function, to appropriate medical personnel. This information can enable physicians to monitor changes in a patient's heart failure and initiate treatment as soon as cardiac decompensation appears, even before the patient exhibits symptoms of this cardiac decompensation.

[0009] The communication means allows the subcutaneous implant to communicate data regarding cardiac and / or respiratory function to equipment located outside the patient's body, such as a communications repeater and / or computer server, while limiting energy consumption by the subcutaneous implant. The issue of energy autonomy for subcutaneous implants is essential in this field, as it ensures that patients avoid the need for surgery to replace the implant for as long as possible.

[0010] Low-energy Bluetooth connections, known by the acronym BLE for "Bluetooth Low Energy," are used in a variety of applications, especially to transmit cryptographic keys between two elements that need to be connected. In other words, these low-energy connections have the advantage of being energy-efficient, but can only transmit small amounts of data, such as a few hundred bytes.

[0011] In the present application, BLE connections are also used to communicate data collected by subcutaneous implants with larger dimensions, in particular data relating to cardiac signals collected by accelerometers or electrocardiograms, which can be on the order of several thousand bytes.

[0012] According to a feature of the invention, the communication means are also adapted to communicate, in a communication separate from the data communication, an alert regarding the availability of data collected by at least the accelerometer and the electrocardiograph. It is clear that the problem of the size of the information transmitted over the BLE connection does not arise for alerts consisting of messages of only a few bytes.

[0013] According to one aspect of the present invention, a communication protocol for communicating data between the subdermal implant and the communication repeater and / or computer server is configured so that communication of data from the implant is performed in multiple consecutive sessions for transmitting partial data. Communication via a low-energy Bluetooth connection between the communication means of the subdermal implant and the communication repeater and / or computer server limits the power consumption of the subdermal implant and thus optimizes the service life of the subdermal implant. This type of communication solution is particularly advantageous when implemented with a specific communication protocol, since communication using a low-energy Bluetooth connection only allows for the exchange of small amounts of data. This type of communication protocol also allows the subdermal implant to send alerts to the communication repeater and transmit all data collected by the subdermal implant, even in the case of large amounts of data.

[0014] More specifically, each data item collected by the accelerometer and / or electrocardiogram is divided into a plurality of partial data items, the juxtaposition or combination of which forms said collected data item, and the communication protocol implemented between the subcutaneous implant and the communication repeater and / or computer server consists of transmitting each of these partial data items sequentially, it being understood that this partial data is on the order of bytes or hundreds of bytes, a size advantageous for the low energy communication implemented by the present invention for data communication from the subcutaneous implant.

[0015] Thus, data collected by the subcutaneous implant can be reconstructed by juxtaposing the partial data consecutively received by the communication repeater and / or computer server. According to a feature of the present invention, data collected by the subcutaneous implant is reconstructed by combining the partial data consecutively received by the communication repeater and / or computer server, and a combining sequence is defined between the subcutaneous implant and the communication repeater and / or computer server. In other words, for security reasons, particularly when transferring medical data, the subcutaneous implant can be configured so that data communication is encrypted, and data can be correctly reconstructed only if the sequence for combining the partial data is known to the communication repeater and / or computer server. This combining sequence may always be the same between the implant and the repeater and / or computer server, and therefore not be revealed during communication, or it may change with each data communication, and one of the transmitted partial data items contains information about the combining sequence.

[0016] As described above, the communication protocol enables the subcutaneous implant to communicate the collected data using a low-energy Bluetooth connection by multiple successive sessions for transmitting the partial data. Advantageously, the partial data are transmitted one after the other. According to a feature of the invention, the communication protocol is configured such that the partial data items include at least one information item regarding the number of partial data items forming the data communication. According to a feature of the invention, the partial data containing information regarding the number of partial data items forming the data communication only contains this information. According to a feature of the invention, the successively transmitted partial data include the partial data containing information regarding the number of partial data items forming the data communication and one or more other partial data items containing at least a portion of the data collected by the subcutaneous implant.

[0017] For example, if the data collected by the subcutaneous implant is on the order of 1000 bytes and needs to be divided into "n" data portions in order to transmit the entire data over the BLE connection, the communication protocol may be configured to communicate "n+1" data portions, including a first data portion containing information followed by "n" data portions, and "n" subsequent data portions each containing a portion of the collected data.

[0018] According to a feature of the present invention, the communication protocol for communicating data between the subcutaneous implant and the communication repeater is different from the communication protocol for exchanging data between the communication repeater and the computer server.

[0019] When transferring data initially collected by the accelerometer or electrocardiograph of the subcutaneous implant, the communication protocol, more specifically, the number of interactions implemented for communication between the subcutaneous implant and the communication repeater, is different from the communication protocol, more specifically, the number of interactions implemented for communication between the communication repeater and the computer server.

[0020] Bluetooth low energy communication is implemented to limit the energy consumption of the subcutaneous implant and extend its service life. This consideration is less important for communication repeaters, which may be equipped with a more powerful external battery or connected directly to the electrical network for their power source. The communication repeater may also communicate information transmitted by the subcutaneous implant over longer distances, for example, via a Wi-Fi connection, which allows for the exchange of larger amounts of data than a low energy Bluetooth connection.

[0021] In other words, according to one aspect of the present invention, the BLE connection is specific to the communication between the subcutaneous implant and the communication repeater, and the communication between the communication repeater and the computer server is via a high-speed communication network that allows data to be communicated over significant distances and also allows for large data transfers.

[0022] For example, all data collected by the subcutaneous implant during a given acquisition period may be transferred from the subcutaneous implant to the communications repeater in approximately 10 consecutive coded messages, while the same data may be sent from the communications repeater to the computer server in a single message.

[0023] According to one aspect of the present invention, a subcutaneous implant includes a temperature sensor configured to measure the body temperature of a living subject. It is understood that the temperature sensor is used to measure the body temperature of a patient in whom the subcutaneous implant is implanted. In particular, the temperature sensor can be used to detect immune responses, possible signs of infection, and triggers of heart failure decompensation. This type of immune response is particularly evident when the body temperature exceeds 38°C.

[0024] According to one aspect of the present invention, a subcutaneous implant includes at least one casing on which at least a first electrode and a second electrode are disposed. These first and second electrodes are used to transmit data regarding the electrical function of the patient's heart. The first and second electrodes are conductive surfaces for collecting electrical signals. These electrical signals are transmitted to an electrocardiograph on a printed circuit board. The electrocardiograph calculates the potential difference between the first and second electrodes to obtain electrophysiological data such as heart rate and its variability, the width of the QRS complex, and the duration of the QT segment. Furthermore, the data obtained by the electrocardiograph by calculating the potential difference can be combined with data obtained by the accelerometer to obtain complementary data such as the pre-ejection period, i.e., the period between the electrical depolarization of the ventricle and the onset of ventricular ejection. Note that this pre-ejection period represents the duration of the left ventricle's contraction relative to a given volume of blood in the left ventricle during each contraction.

[0025] Additionally, the first and second electrodes may also be used to measure bioelectrical impedance values. These electrodes are capable of emitting and receiving a low-intensity current and an associated control module, here on a printed circuit board housed in a case, configured to measure the resistance of the biological tissue through which the current passes between the emitting and receiving electrodes. More specifically, this characteristic of the electrodes emitting and receiving a low-intensity current allows for data to be obtained regarding changes in blood volume that occur during the cardiac cycle. It will be understood that this data may be used to obtain data regarding systolic time intervals.

[0026] Furthermore, the measurement of bioelectrical impedance values ​​by the electrodes also allows obtaining data on respiratory parameters such as tidal volume, which represents the patient's resting lung volume during normal inspiration, i.e., when the patient is not exerting any particular effort, and provides an indication of the amount of air entering the lungs during inspiration. A decrease in this tidal volume may indicate the presence of fluid in the lungs, a possible sign of the onset of heart failure decompensation.

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

[0028] According to one aspect of the invention, the accelerometer is capable of calculating linear acceleration along three orthogonal axes, and the computer server is configured to calculate changes in at least one hemodynamic and / or respiratory parameter based on accelerometer data particularly relating to at least one of said axes.

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

[0030] According to one aspect of the invention, an algorithm is implemented on a computer server, the algorithm configured to analyze data acquired and transmitted by the subcutaneous implant to assess the risk of developing heart failure decompensation.

[0031] The present invention also relates to a communication method for the aforementioned monitoring system, the communication method comprising: At least a first step in which a communication repeater scans a surrounding space to detect a subcutaneous implant; at least a first additional step of generating an alert signal specifying that the subcutaneous implant may exchange data related to cardiac operation with a computer server; and at least one second step in which data or control instructions are exchanged between the subdermal implant and a computer server by a communications repeater, wherein a low-energy wireless communications network implemented for communications between the subdermal implant and the communications repeater is different from a high-speed wireless communications network implemented for communications between the communications repeater and the computer server.

[0032] The communication repeater can scan the surrounding space for signals emitted by the subcutaneous implant over a radius of approximately 5 meters around the communication repeater. This detection distance from the communication repeater limits the possibility of external devices connecting to the communication repeater.

[0033] According to a feature of the invention, the communication method performs at least one second auxiliary step, which is performed before the second step, during which the communication relay detects the subcutaneous implant and transmits a request to identify the subcutaneous implant to a computer server, which processes the identification request by transmitting, via the communication relay to the subcutaneous implant, an encryption key specific to the subcutaneous implant and a data retrieval request and / or control command.

[0034] The computer server is understood to "process" the identification request insofar as it is configured to use the identification request to identify the subcutaneous implant and to select an action to be performed in response to this identification of the subcutaneous implant. If the computer server recognizes the subcutaneous implant via the identification request, the computer server can determine that no action is required, e.g., that data feedback from the implant is not required, and as a result, communication between the implant and the computer server is not established. Information to this effect may be transmitted to the implant via a communications relay. If the computer server recognizes the subcutaneous implant via the identification request, the computer server can determine that feedback data acquired by the implant needs to be transmitted or that new operating parameters need to be transmitted to the implant. The computer server can then be configured to transmit a unique encryption key specific to the implant in addition to data retrieval instructions and / or control instructions, so that the implant can recognize that the communication is indeed coming from an authorized computer server and not an attempt to compromise its data.

[0035] The control instructions sent to the subcutaneous implant may include instructions to change the operating parameters of the subcutaneous implant, for example, the data acquisition frequency.

[0036] Note that the identification request transmitted by the subcutaneous implant includes information specific to the 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 enables the computer server to recognize the subcutaneous implant detected by the communication repeater and to tailor the transmission of information, such as control commands and / or data retrieval requests, to the subcutaneous implant depending on the recognized subcutaneous implant.

[0037] In one embodiment of the communication method, data collected by the subdermal implant passes through the communication relay, i.e., the data is not stored in the communication relay. In other words, it is understood that in this version of the communication method, the communication relay allows data collected by the subdermal implant to be transmitted between said subdermal implant and a computer server, but does not process said data collected by the subdermal implant. This is advantageous in terms of data security, as the communication relay does not need to be protected as effectively as, for example, a computer server.

[0038] According to a feature of the present invention, the communication repeater is configured to be able to temporarily store data from the subcutaneous implant, in other words, in a standard operating mode, i.e., when there is no malfunction of the communication network between the communication repeater and the computer server and no malfunction of the BLE connection between the communication repeater and the subcutaneous implant, the communication repeater does not store data, but in a degraded operating mode, when there is a potential or proven malfunction of the communication means, the communication repeater temporarily stores data until the communication means are re-established.

[0039] It is understood that this version of the communication method allows the communication relay to retain data collected by the subdermal implant if the computer server is unavailable and therefore transfer of information from the communication relay to the computer server is not possible. This version of the communication method ensures that data collected by the subdermal implant is not lost if the computer server is unavailable.

[0040] According to another feature of the present invention, the communications relay is capable of temporarily storing information transmitted by the computer server including at least control instructions and encryption keys specific to the subdermal implant, enabling the communications relay to connect to the subdermal implant.

[0041] "Temporarily" means that the communication repeater retains the information sent by the computer server until the next connection between the communication repeater and the subcutaneous implant.

[0042] In this embodiment, it is understood that when the communications repeater detects the presence of a subdermal implant and the subdermal implant signals that it has data to transmit, the communications repeater can establish a connection with the subdermal implant without going through a computer server.

[0043] This version of the communication method has the advantage that, for example, data collected by the subcutaneous implant or control commands can be transmitted to the subcutaneous implant when the computer server is unavailable, i.e., when the communication repeater cannot communicate with the computer server.

[0044] In this version of the communication method, it is understood that the communication repeater can store an encryption key specific to the subcutaneous implant with which it communicates, and that the communication repeater comprises suitable means for decrypting and communicating this encryption key to the subcutaneous implant. In this regard, at least the means for decrypting the encryption key are protected by encryption means. Such a version has the advantage that data collected by the subcutaneous implant can be retrieved independently of the operation of the computer server.

[0045] It should also be noted that regardless of the version of the communication method implemented, the data collected by the subdermal implant and transmitted to the computer server, and the information transmitted by the computer server to the subdermal implant, is encrypted.

[0046] According to one aspect of the present invention, communication between the communication repeater and the subdermal implant is provided by a low-energy Bluetooth connection, and communication between the communication repeater and the computer server is provided by a high-speed Internet connection. The Bluetooth connection minimizes the amount of energy stored in the subdermal implant, but on the other hand, requires more data to be transmitted between the subdermal implant and the communication repeater, so that the communication repeater can retrieve all data acquired by the subdermal implant. Depending on the role assigned to the communication repeater, the communication repeater may transmit data received from the subdermal implant directly to the computer server, or the communication repeater may concatenate data received consecutively from the subdermal implant over a given period of time and transmit the concatenated data to the computer server in a single transmission.

[0047] According to a feature of the present invention, a communications repeater is configured to connect to a single subcutaneous implant, the communications repeater being configured to continuously scan the surrounding space for said subcutaneous implant.

[0048] According to one feature of the present invention, a communications repeater is capable of detecting multiple subdermal implants, each subdermal implant configured to enable or prevent connection of the communications repeater to the subdermal implant depending on the subdermal implant's recognition of a cryptographic key, the cryptographic key being specific and unique to each subdermal implant, and the cryptographic key being communicated to the subdermal implant by a computer server via the communications repeater.

[0049] It will be appreciated that the encryption key is a means of ensuring that devices wishing to connect to the subcutaneous implant are authenticated by the monitoring system.

[0050] According to a feature of the invention, the subcutaneous implant may be configured to only accept establishing a connection with communication repeaters that have their identifiers in memory, such as the serial number and / or MAC address of the BLE connection. In another embodiment, the subcutaneous implant may be configured to accept attempts from any communication repeater except those on a blacklist, including repeaters that made an initial attempt to connect to the subcutaneous implant without authentication from a computer server, i.e., without the appropriate encryption key.

[0051] Other characteristics, details and advantages of the invention will become more apparent on reading the following description on the one hand and on the other hand the examples of embodiments given by way of indication and not of limitation, with reference to the attached schematic drawings, in which: [Brief explanation of the drawings]

[0052] [Figure 1] 1 is a general view of a subcutaneous implant according to one embodiment of the present invention. [Figure 2] 1 is a highly schematic illustration of the operation of a system for monitoring at least one parameter indicative of the onset of heart failure decompensation in a patient, said patient being equipped with a subcutaneous implant forming part of the monitoring system according to the invention; [Figure 3] 1 is a schematic diagram of one embodiment of a communication method implemented in a monitoring system. DETAILED DESCRIPTION OF THE INVENTION

[0053] First of all, it should be noted that although the drawings illustrate the invention in detail for its implementation, these drawings can of course be used to better define the invention as needed, and it should also be noted that these drawings only show examples of embodiments of the invention.

[0054] The features, variations, and different embodiments of the invention can be associated with one another in various combinations, provided they are not incompatible or mutually exclusive. In particular, it is possible to envision variations of the invention that include only a selection of features described below, in isolation from other features described, if this selection of features confers a technical advantage or is sufficient to distinguish the invention from the prior art.

[0055] In the figures, elements common to several figures retain the same reference numerals.

[0056] FIG. 1 illustrates a medical device that can be implanted in a living organism, more specifically, a subcutaneous implant 2 configured to be inserted under the skin of a living organism (hereinafter referred to as a "patient"). In the illustrated embodiment, the subcutaneous implant 2 is positioned under the patient's skin in the chest region between the fourth and fifth intercostal spaces, at the level of the left border of the sternum. Such positioning of the subcutaneous implant 1 allows optimal measurements to be obtained of both cardiac electrical and mechanical parameters. It should be noted that in alternative embodiments of the present invention, the subcutaneous implant 1 may be positioned in the fourth intercostal space, specifically at the level of the fifth intercostal space, the anterior axillary line, or the midclavicular line.

[0057] As can be seen in Figure 1, the subdermal implant 2 extends with a main longitudinal direction of elongation parallel to the axis L. More specifically, Figure 1 shows a first side 4 of the subdermal implant 2.

[0058] The subdermal implant 2 includes a first measuring end 8 at the level of the first longitudinal end 6. This first measuring end 8 includes a first electrode 10, which is disposed on the first surface 4. In an illustrative and non-limiting example of the present invention, the first measuring end 8 is formed in a polymer product 12, such as an epoxy polymer, and the first electrode 10 is disposed on a surface within the polymer, creating an electrically insulating environment around the first electrode 10. The first electrode 10 is electrically connected to a printed circuit board present in the subdermal implant so that potential information can be extracted and / or a low-intensity current can be emitted. However, it is understood that the polymer product provides electrical insulation from the remaining metallic parts of the implant, particularly the second electrode, as will be explained in more detail below. By insulating the first electrode 10 from the second electrode in this way, an electronic chip mounted on the subdermal implant 2 can measure the potential difference between these two electrodes to form an electrocardiograph.

[0059] The first measuring end may be made of another material, provided that the first electrode is electrically insulated as described above and allows the subdermal implant 2 to be placed under the patient's skin without risk to the patient. Alternatively, the first measuring end may be made of the same material as the rest of the subdermal implant, for example a metallic material such as titanium, except that an insulating coating, such as parylene, and an electrically insulating material extending through the thickness of the case is provided around the first measuring end exposing the first electrode.

[0060] Furthermore, this first measuring end 8 comprises an antenna (not shown here) capable of transmitting information collected by the subcutaneous implant 2, as will be explained in more detail in the following description.

[0061] The subdermal implant 2 includes an orifice 14 located at the level of the first end 6 of the subdermal implant 2. Advantageously, this orifice 14 allows the subdermal implant 2 to be attached under the patient's skin by a link. More specifically, this orifice 14 allows a link, such as a thread, which in the illustrated embodiment passes through the subdermal implant 2 from the first surface 4 to the second surface opposite the first surface and is not visible here, to pass through the orifice. The thread is then attached to the patient's biological tissue to maintain the subdermal implant 2 implanted.

[0062] The subcutaneous implant 2 comprises a second measuring end 18 at the level of a second end 20 opposite the first end 6. This second measuring end 18 comprises a second electrode 22 which, in combination with the first electrode 10 and the electronic chip, forms an electrocardiograph as described above.

[0063] It should be noted that for optimal operation of the subcutaneous implant 2, it is advantageous to implant the subcutaneous implant 2 so that the first electrode 10 and the second electrode 22, and more generally the first surface 4, face the patient's heart.

[0064] Between the first end 6 and the second end 20, the subdermal implant 2 comprises a case 24 comprising at least one printed circuit board, an accelerometer, and an electronic chip to which the first electrode 10 and the second electrode 22 are electrically connected to form an electrocardiograph. Advantageously, the case 24 also comprises a temperature sensor, for example, to highlight potential infections in the patient that increase the risk of heart failure decompensation.

[0065] The case 24 comprises a first portion housing the electrical energy storage means, dimensioned to ensure adequate autonomy of the subcutaneous implant, and a second portion housing the aforementioned accelerometer and electrocardiograph chips. In the illustrated example, each of these portions of the case, as well as the two ends where the electrodes are located, are formed by hulls that are made independently of each other and welded together in a second stage. Alternatively, some of the portions between the case and the measuring end may be made in one piece. For example, in an alternative embodiment of the invention not shown here, the case may be made in one piece from the first end to the second end and configured to house the battery and printed circuit board.

[0066] In each of these cases, the first electrode 10 and the second electrode 22 are advantageously positioned at opposite ends of the subcutaneous implant.

[0067] Although not limiting to the present invention, the case may be made of titanium and electrical insulating means are implemented on either side of the case to electrically insulate the electrodes 10, 22 integrated into the case 24 from each other.

[0068] In other words, the electrical insulating means ensure that there are no conductive elements connecting the first electrode 10 and the second electrode 22 .

[0069] It should be noted that without departing from the context of the present invention, the first electrode and the second electrode may be insulated from each other by different insulating materials, preferably polymers, as long as this does not present a health risk to the patient in whom the subcutaneous implant 2 is implanted.

[0070] Furthermore, the subdermal implant 2 comprises electrical energy storage means housed within the case 24, as previously described. This electrical energy storage means may be a primary battery, such as an electric cell, or a rechargeable accumulator. The electrical energy storage means is configured to provide electrical energy to the various elements of the subdermal implant 2, in particular the printed circuit board.

[0071] As previously mentioned, at least one accelerometer, an electrocardiograph electronic chip, and a temperature sensor are housed within the case 24, and the electrocardiograph electrodes are disposed on the case 24.

[0072] In one embodiment, the accelerometer may be a three-axis accelerometer capable of detecting linear acceleration along the vertical, horizontal, and sagittal axes. An average acceleration value may be calculated by normalizing the three values ​​detected on one axis. In an alternative embodiment of the invention, the accelerometer may be a simple accelerometer configured to detect linear acceleration along a single axis.

[0073] The data obtained by the accelerometer is used to analyze, among other things, the patient's hemodynamic and respiratory parameters, as well as information regarding the patient's posture at the time the information was acquired by the subcutaneous implant 2, i.e., whether the patient was standing or lying down, using an estimate of the patient's tilt angle in the recumbent position. Indeed, during the onset of heart failure decompensation, patients experience difficulty breathing when the tilt is zero, i.e., lying flat. To overcome this problem, the patient's torso is gradually straightened using additional pillows, and the change in tilt is detected by the accelerometer. It will be appreciated that this information regarding the patient's tilt, especially while sleeping, allows a physician to determine whether intervention is necessary by cross-referencing this information with various markers, if necessary.

[0074] As previously mentioned, the subdermal implant 2 comprises an electrocardiograph comprising an electronic chip disposed on a printed circuit board and a first electrode 10 and a second electrode 22 disposed on the case 24. The combination of the electrocardiograph with a three-axis accelerometer advantageously facilitates analysis of data from the latter, in particular analysis of heart sounds or the pre-ejection period, commonly known as "PEP."

[0075] The temperature sensor measures the patient's body temperature. This temperature sensor provides information about the patient's temperature in a more stable manner than external temperature measurements. This information about the patient's temperature can be used to identify any immune response in the patient, which may indicate a potential infection. During an infection, the patient is at greater risk of cardiac decompensation. It is understood that this data on the patient's temperature allows the physician monitoring the patient to be more cautious about the signals from the triaxial accelerometer and electrocardiograph.

[0076] The operation of these on-board devices in the subcutaneous implant, namely the electrocardiograph, accelerometer, and temperature sensor, is advantageously controlled by a printed circuit board, more specifically a microcontroller. It is understood that the microcontroller can, for example, operate the on-board devices in the subcutaneous implant to acquire data at a preset frequency. It should be noted that when the subcutaneous implant 2 is assembled, the printed circuit board is embedded in resin or silicone, by way of non-limiting example. This resin or silicone provides a rigid connection between the accelerometer and the case, so that any movement perceived by the accelerometer represents body movement, including movement of the subcutaneous implant, and can therefore be used for signal processing by the monitoring system.

[0077] The frequency at which measurements are taken is defined by a control system on a remote computer server, and this frequency may be changed over time to suit the measures required to monitor the patient's condition.

[0078] More specifically, the measurement frequency of the subdermal implant 2 is one data acquisition per day in a nominal use mode. However, the patient's physician may change the number of daily acquisitions to more accurately monitor disorders or changes in the patient's condition over the course of a day. Alternatively, the physician may choose to reduce the number of daily data acquisitions performed by the subdermal implant 2, for example, if the patient's health condition is stable.

[0079] It will be appreciated that the number of daily data acquisitions performed by the subcutaneous implant 2 can be adjusted by the physician as needed. Note that in the case of once-daily data acquisition, this acquisition is advantageously performed at night while the patient is asleep. In this way, the data collected by the subcutaneous implant 2 is not disturbed by physical activity, such as climbing stairs. More specifically, data acquisition by the subcutaneous implant 2 is advantageously performed at a fixed time during the night while the patient is in a stable state, which can be repeated daily.

[0080] Furthermore, the subdermal implant 2 acquires data at time intervals of approximately 30 seconds. Such a long data acquisition period ensures that the subdermal implant 2 acquires data over a sufficiently large number of cardiac or respiratory cycles to obtain information that allows a physician to accurately analyze the risk of heart failure decompensation. The duration of data acquisition performed by the subdermal implant 2 may be longer, for example, approximately 2 minutes, to improve the accuracy of the collected information. Note that the duration of data acquisition may be adjusted by a physician according to the accuracy of the information required. Additionally, the duration of data acquisition performed by the subdermal implant 2 may be longer than 2 minutes, depending on the amount of data that can be stored in the subdermal implant 2.

[0081] Furthermore, the printed circuit board comprises communication means that enable the subdermal implant 2 to transmit and / or receive information by means of the aforementioned antenna. More particularly, these communication means are wireless communication means that use the Bluetooth® telecommunications standard, or more precisely the Bluetooth Low Energy protocol, better known by the acronym "BLE".

[0082] As described above, the subcutaneous implant 2 is configured to collect data autonomously, i.e., without patient intervention, and the data is processed and stored on a computer server in communication with the subcutaneous implant to provide a physician with information regarding changes in specific parameters over an acquisition period. By analyzing changes in at least one parameter indicative of cardiac decompensation, a physician can assess the risk of heart failure decompensation in a patient implanted with the subcutaneous implant 2. It should be noted that in the illustrated embodiment, particularly the embodiment shown in FIG. 2 described below, the subcutaneous implant 2 is implanted in a patient suffering from chronic heart failure. Of course, in alternative embodiments of the present invention, the subcutaneous implant 2 may be implanted in a healthy patient not suffering from heart failure, and the subcutaneous implant 2 may enable the onset of heart failure to be detected.

[0083] The computer server is configured to provide a physician, such as the patient's attending physician, with changes in parameters determined from the data collected and transmitted by the subcutaneous implant 2. In particular, the physician may analyze changes in heart sounds, changes in the duration of the pre-ejection period (PEP), changes in respiratory frequency, and / or, but not limited to, changes in the patient's tilt during sleep.

[0084] The computer server can be configured to communicate all the information it possesses, i.e., all the changes in the parameters that it has been able to calculate based on all the data acquired by the subcutaneous implant. The accumulation of cardiac and / or respiratory markers, the changes of which are assimilated to deterioration, allows the physician to highlight the risk of developing cardiac decompensation.

[0085] Alternatively, the computer server may be configured to communicate to the physician only information regarding changes in certain parameters, particularly changes in markers known to deteriorate first in the event of cardiac decompensation, such as changes in the amplitude of heart sounds and changes in the duration of the pre-ejection period, particularly when the patient's health condition is declared stable. In other words, the computer server may be configured to select the information to be sent to the physician, and to transmit information regarding the evolution of other parameters only if it is determined that the evolution of the early markers indicates the likely emergence of an episode of cardiac decompensation.

[0086] For example, the amplitude of heart sounds can be analyzed based on the processing of acceleration signals. This processing of the signals is advantageously performed remotely on a computer server, where the computer server retrieves all data collected by the subcutaneous implant over a given acquisition period. The processing of the signals can consist of dividing the acceleration measurement signals into time cycles, each of which is analyzed to identify characteristic segments of heart sounds, known as segments S1, S2, and S3. The amplitudes of the identified segments in each time cycle are averaged to calculate three heart sound values ​​per acquisition period. By comparing these average heart sound values ​​from one acquisition period with another, the computer server is configured to determine changes in the amplitude of the heart sounds. Thus, a physician can receive information about the increasing or decreasing trends of specific heart sounds S1, S2, and S3 on an appropriate display. For example, an increase in sound S1 over time and / or a decrease in sound S3 over time can be indicative of cardiac decompensation.

[0087] Another marker to analyze for changes may be respiratory rate. During heart failure decompensation, the lungs may fill with fluid. In this case, the patient uses less tidal volume with each breath, and the patient naturally compensates for this decrease in the amount of air used during normal breathing by increasing the breathing frequency.

[0088] Another of these markers could be the patient's tilt during sleep: indeed, during episodes of decompensation, patients are known to exhibit dyspnea that they compensate by slightly raising their upper body during sleep, and therefore analysis of changes in the patient's tilt during sleep is informative.

[0089] The cross-analysis of these different parameters allows the physician to define very precisely the patient's risk of heart failure decompensation and to intervene before the patient has to be hospitalized.

[0090] 2 illustrates a system 30 for monitoring the onset of heart failure decompensation, in which a subcutaneous implant 2 is configured to collect measurements related to cardiac function of a patient 32 in whom the subcutaneous implant 2 is implanted.

[0091] Additionally, subdermal implant 1 is configured to communicate with a communications relay 34, such that information collected by subdermal implant 2, including various measurements, can be transmitted from subdermal implant 2 to communications relay 34. This communications relay 34 can be an electronic case located outside the patient's body or a mobile application on a mobile device, such as a smartphone or tablet. Subdermal implant 2 communicates with communications relay 34 via a low-energy Bluetooth® connection 36, transmitting messages having a limited amount of data, such as 241 bytes. Thus, communication between communications relay 34 and subdermal implant 2 can be accomplished via multiple messages, each containing a portion of the information collected by subdermal implant 2. Security measures are implemented to ensure the integrity and confidentiality of all information collected by subdermal implant 2.

[0092] More specifically, the subdermal implant 2 may generate a signal or alarm that allows the implant to be detected by the communications repeater 34, as will be explained in more detail below. Once the subdermal implant 2 is detected and connected to the communications repeater 34, the subdermal implant 2 may implement a specific communications protocol via the communications means that allows all data collected by the on-board equipment within the subdermal implant 2 to be communicated via a low-energy connection.

[0093] This communication protocol is specific to the subcutaneous implant 2 and the means of communication of the subcutaneous implant 2. In particular, implementing a low energy BLE connection to communicate medical data involves breaking down the data collected by the accelerometer and / or electrocardiogram into "n" portions of data that take the form of signals over a given time cycle and are therefore one or several thousand bytes in size.

[0094] In particular, the communication protocol may be configured such that when data must be communicated to the communication repeater, the subdermal implant 2 transmits a first message or a first portion of data that includes specific information regarding the number of messages or portions of data that the subdermal implant 2 will transmit to transmit all of the collected data. This first message initiates a transmission sequence that includes as many messages as necessary for the subdermal implant 2 to transmit all of the collected data.

[0095] It should be noted that communicating all of the data collected by subdermal implant 2 in multiple messages or partial data requires the prior step of fragmenting the information collected by subdermal implant 2 into a plurality of these partial data. It should also be noted that the communication relay and / or computer server may also be configured to be able to reconstruct the data from the partial data by juxtaposing the partial data in the order in which they were received or by combining them according to a combination order specific to this data communication.

[0096] Data transfer using the Bluetooth low power protocol requires relative proximity between the subdermal implant 2 located inside the patient 32 and the communication repeater 34 located outside the patient 32. To this end, the communication repeater 34 may be advantageously located, for example, in the bedroom of the patient 32 wearing the subdermal implant 2, so that data exchange can occur during the night when the patient 32 is located close to the communication repeater 34.

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

[0098] According to the present invention, the subcutaneous implant 2 can transmit data regarding the electrical function of the patient's heart 32 to a computer server 38 via a low-energy Bluetooth connection 36 and a communication repeater 34. This data is acquired by the electrocardiograph, accelerometer, and, if applicable, a temperature sensor. This information can be read by a physician, who, directly or after appropriate signal processing, may have information regarding the heart sounds S1, S2, and S3 associated with systole and diastole, heart rate, heart rate variability, width of the QRS complex, duration of the QT segment, heart rate, and pre-ejection period, in order to perform a possible diagnosis of cardiac decompensation. It will be appreciated that some of this data may be advantageously estimated by cross-referencing information from the triaxial accelerometer and the electrocardiograph.

[0099] It should be noted that the information regarding changes in parameters indicative of cardiac decompensation that has been calculated and stored on the computer server 38 is communicated to the physician by an information display means that may consist of the physician's computer screen, the computer being remotely connected to the server via an internet connection or to a mobile communications device such as a smartphone or tablet. It will be appreciated that the computer server 38 is advantageously delocalized, i.e., remotely hosted, so that it may be accessed by multiple physicians as long as they have secure access to retrieve data relating to the patient, and only the patient. Alternatively, and without modifying the operations described above, the computer server 38 can be considered to be the physician's computer or mobile communications device, with this computing or telecommunications equipment comprising software capable of performing the operations described above with respect to the computer server.

[0100] The information transmitted on the computing-assisted display means or by mobile communication may be transmitted in its entirety without any pre-processing or with a selection of the information provided to the physician, which may for example limit the transmission of sensitive data depending on the type of display means used.

[0101] It should further be noted that the computer server 38 may comprise an algorithm capable of performing a first analysis of the data collected by the subcutaneous implant 2 and generating an alert to a physician if the information resulting from the processing of this data indicates changes that are considered to be characteristic of a risk of cardiac decompensation.

[0102] A control system running on the computer server 38 recognizes and verifies the subdermal implant 2 .

[0103] The computer server 38 may communicate with the subdermal implant 2 via the communication repeater 34 to change the acquisition frequency and / or time slots for these acquisitions and / or the type of data collected. By way of example, the computer server may generate a specific data retrieval request in the direction of the subdermal implant 2, or may process only the temperature acquisition immediately upon receiving the specific data retrieval request or during the next programmed acquisition session.

[0104] In the illustrated embodiment, communication between the communication relay 34 and the computer server 38 is ensured via a secure internet connection 40. More specifically, this internet connection 40 is a WIFI connection. It will be understood that the exchange of information between the communication relay 34 and the computer server 38 relies on the internet connection 40.

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

[0106] The communication repeater 34 is capable of detecting all subdermal implants 2 within a space of approximately 5 meters. However, in order for the communication repeater 34 to be able to connect to one of the subdermal implants 2, the communication repeater 34 must provide this implant with an encryption key sent by the computer server 38. This encryption key is unique to each subdermal implant 2. Note that the communication repeater does not necessarily know the key, but may present it to the subdermal implant, depending on the communication mode implemented.

[0107] In this context of communications established between the subdermal implant and a communications relay, the subdermal implant 2 may be configured to store in memory one or more communications relays 34 to which it may connect, and / or to blacklist any devices that attempt to connect without authorization from the computer server 38.

[0108] In a particular safe mode of operation, the subdermal implant may be configured to connect to a single communications repeater 34. This subdermal implant 2 is then uniquely associated with said communications repeater 34.

[0109] It will be appreciated that if the communications repeater 34 is configured to be connectable to multiple subcutaneous implants 2 and to act as a relay between each of these implants and the computer server, for example, if multiple people in the same household are fitted with monitoring system subcutaneous implants as described above, the communications repeater will communicate with a single subcutaneous implant at a time using an encryption key specific to each subcutaneous implant provided by the computer server 38 at the acquisition period defined for that subcutaneous implant.

[0110] In particular, the monitoring system 30 enables the implementation of a communication method 42 specific to the present invention, in which the computer server 38 is enabled to receive desired information from the subcutaneous implant 2 in a series of steps.

[0111] This communication method 42 can be seen more clearly in Figure 3. As seen in Figure 3, the communication method 42 performs a first step 44 in which the communication repeater 34 scans the space around the subdermal implant 2. More specifically, it can be seen that the communication repeater 34 is fixedly positioned outside the body of the patient 32 and is constantly searching for signals emitted by the subdermal implant 2.

[0112] In a first additional step 46, the subdermal implant 2 generates an alert signal that enables the communication relay 34 to detect the subdermal implant 2 and specifies that physiological data may be exchanged with the computer server 38. The subdermal implant 2 generates a signal at regular intervals so that the subdermal implant 2 can be detected by the communication relay 34 when the subdermal implant 2 is in close proximity to the communication relay 34. The length of the signal transmission interval can be set to, for example, 5 minutes, 20 minutes, or the like. Similar to the signal emitted during the first additional step 46, this signal can include an indicator that enables the communication relay 34 to recognize that data is available and can be exchanged by the subdermal implant 2. This signal may also not include an indicator; in this case, for example, if the computer server 38 sends information to the communication relay 34 configured for the subdermal implant 2, the communication relay 34 may connect to the subdermal implant 2.

[0113] The operation of Bluetooth and the emission of signals from said subdermal implant 2 require energy. In order to extend the life of the energy storage means of the subdermal implant 2, the subdermal implant 2 is connected to the communication repeater 34, on the one hand, only if the subdermal implant 2 contains information to be transmitted by the communication repeater 34 to the computer server 38, and on the other hand, only if the communication repeater 34 holds information emanating from the computer server 38 and configured for the subdermal implant 2.

[0114] In the illustrated embodiment, communication method 42 performs a second substep 48 that occurs when communication relay 34 detects subdermal implant 2 and subdermal implant 2 emits an indicator that one or more measurement information pieces are suitable for retrieval by computer server 38. During this second substep 48, communication relay 34 detects subdermal implant 2 and computer server 38 generates a communication protocol that includes information that enables communication relay 34 to connect to subdermal implant 2.

[0115] From this second substep 48, it can be seen that the connection between the subdermal implant 2 and the communication relay 34 is managed by the computer server 38. Furthermore, the communication protocol issued by the computer server 38 can strictly limit the connection from the subdermal implant 2 to the communication relay 34 when the subdermal implant 2 holds information required by the computer server 38 or when the communication relay 34 holds information configured on the subdermal implant 2.

[0116] The communication method 30 performs a second additional step 50, which occurs before the second auxiliary step 48, during which the communication relay 34 transmits information regarding the detection of the subdermal implant 2 to the computer server 38. It is understood that this step in the communication method 30 is part of a process by which the computer server 38 controls the connection of the subdermal implant 2 to the communication relay 34. The transmission of this detection signal by the communication relay 34 triggers a request from the computer server 38 regarding the presence or absence of a connection between the communication relay 34 and the subdermal implant 2.

[0117] The authorization of the connection between the communications relay 34 and the subdermal implant 2 by the computer server 38, in the illustrated embodiment, enables the second step 52 of the communications method 30 to be performed. During this second step 52 of the communications method 30, the subdermal implant 2 exchanges information with the computer server 38 via the communications relay 34. Alternatively, information may be exchanged between the computer server 38 and the subdermal implant 2, or from the computer server 38 to the subdermal implant 2. As discussed above, such an exchange enables the subdermal implant 2 to be remotely configured.

[0118] The present invention achieves its stated objectives by providing a system for monitoring at least one parameter indicative of the onset of cardiac decompensation. This detection of said onset of cardiac decompensation is achieved 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 that forwards messages to the computer server.

Claims

1. 1. A system (30) for monitoring at least one parameter indicative of the onset of heart failure decompensation in a living organism, the monitoring system (30) comprising at least one subcutaneous implant (2) configured to be introduced under the skin of the living organism, the subcutaneous implant (2) comprising at least one electrocardiograph and at least one accelerometer configured to collect data related to cardiac function of the living organism, the monitoring system (30) also comprising a computer server (38) and a communications repeater (34) configured to enable 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 of hemodynamic and / or respiratory and / or electrophysiological parameters based on the data collected by at least the accelerometer and the electrocardiograph, the subcutaneous implant (2) comprising communications means configured to communicate the data collected by at least the accelerometer and the electrocardiograph over a low-energy Bluetooth connection (36).

2. 2. The monitoring system (30) of claim 1, wherein the communication means is also configured to communicate, in a communication separate from the data communication, an alert regarding the availability of data collected by at least the accelerometer and the electrocardiograph.

3. 3. The monitoring system (30) of claim 1 or 2, wherein a communication protocol for communication of data between the subdermal implant (2) and the communication repeater (34) and / or the computer server (38) is configured such that communication of data from the subdermal implant (2) to the communication repeater (34) occurs in multiple consecutive data transmission sessions.

4. 4. The monitoring system (30) of claim 1, wherein a communication protocol for communicating data between the subcutaneous implant (4) and the communication repeater (34) is different from a communication protocol for exchanging data between the communication repeater (34) and the computer server (38).

5. The monitoring system (30) of any one of claims 1 to 4, wherein the subcutaneous implant (2) comprises a temperature sensor configured to measure the body temperature of the living organism.

6. 6. The monitoring system (30) of claim 1, wherein the subcutaneous implant (2) comprises at least one case (24) in which at least a first electrode (10) and a second electrode (22) are arranged.

7. 7. The monitoring system (30) of any one of claims 1 to 6, wherein the computer server (38) is configured to use the data collected by the subcutaneous implant (2) to calculate at least one change in heart sounds and / or pre-ejection period and / or respiratory rate and / or heart rate.

8. 8. The monitoring system (30) of claim 1, wherein the accelerometer is capable of calculating linear acceleration along three orthogonal axes, and the computer server (38) is configured to calculate changes in at least one hemodynamic and / or respiratory parameter based on accelerometer data particularly related to at least one of the axes.

9. 9. The monitoring system (30) of claim 1, wherein an algorithm is implemented on the computer server, the algorithm being configured to analyze the data acquired and transmitted by the subcutaneous implant (2) to assess the risk of developing heart failure decompensation.

10. A communication method (42) for a monitoring system (30) according to any one of claims 1 to 9, said communication method (42) comprising: At least one first step (44) in which the communication repeater (34) scans the surrounding space to detect the subcutaneous implant (2); at least a first additional step (46) of generating an alert signal specifying that the subcutaneous implant (2) may exchange data related to the operation of the heart with a computer server (38); and at least one second step (52) in which data or control instructions are exchanged between the subdermal implant (2) and a computer server (38) by a communications repeater (34), wherein a low-energy wireless communications network implemented for communications between the subdermal implant and the communications repeater is different from a high-speed wireless communications network implemented for communications between the communications repeater and the computer server.

11. 11. The communication method of claim 10, further comprising at least one second auxiliary step (48) performed before the second step (52), in which the communication relay (34) detects the subcutaneous implant (2) and transmits a request to the computer server (38) to identify the subcutaneous implant (2), and the computer server (38) processes the identification request by transmitting a cryptographic key specific to the subcutaneous implant and a data retrieval request and / or control command to the subcutaneous implant (2) via the communication relay.

12. 12. The communication method of claim 10, wherein the communication between the communication repeater (34) and the subcutaneous implant (2) is provided by a low-energy Bluetooth connection (36), and the communication between the communication repeater and the computer server is provided by a high-speed Internet connection.

13. 13. The communication method according to any one of claims 10 to 12, wherein the communication repeater (34) is configured to connect to a single subcutaneous implant (2), and the communication repeater (34) is configured to continuously scan the surrounding space to search for the subcutaneous implant (2).

14. 13. The communication method of claim 10, wherein the communication relay (34) is capable of detecting a plurality of subcutaneous implants (2), each subcutaneous implant (2) being configured to enable or prevent the communication relay (34) from connecting to the subcutaneous implant (2) depending on the recognition by the subcutaneous implant (2) of an encryption key, the encryption key being unique to each subcutaneous implant (2), and the encryption key being communicated to the subcutaneous implants (2) by the computer server (38) via the communication relay (34).

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