Device for detecting magnetic signals generated by a beating heart

Abstract

The invention relates to a device (2) for detecting magnetic signals generated by a beating heart (M), having at least one nitrogen-vacancy-centre, NV, magnetometer unit (4), which is designed to detect a magnetic field strength and / or field direction, at least one further sensor (5), a signal processing unit (170, 11), to which the at least one NV magnetometer unit (4) and the at least one further sensor (5) are connected, wherein the device is designed to determine, by means of the signal processing unit (170, 11), at least one effective magnetic field strength and / or at least one effective field direction from the signals of the at least one NV magnetometer unit (4) and of the at least one further sensor (5).

Description

[0001] Description

[0002] title

[0003] Device for detecting magnetic signals generated by a beating heart

[0004] The present invention relates to a device for detecting magnetic signals generated by a beating heart

[0005] Background of the invention

[0006] Optically pumped quantum sensors or those based on NV centers in diamond are particularly suitable for measuring very small magnetic field strengths. DE 10 2022 204 526.2 describes a magnetometer that uses optically pumped and optically detected magnetic resonance (ODMR). This method exploits the fact that the energy levels of certain spin states of unpaired electrons split under the influence of an external magnetic field, the so-called Zeeman effect.

[0007] The splitting of energy levels results in altered transitions during relaxation from excited states, which can then be measured, for example, by optical excitation and frequency-dependent detection of the resulting fluorescence radiation or by observing optical properties such as light absorption. The measured optical parameters can then be used to determine the magnetic field strength.

[0008] Disclosure of the invention

[0009] According to the invention, a device for detecting magnetic signals generated by a beating heart is proposed, having the features of claim 1. Advantageous embodiments are the subject of the subclaims and the following description.

[0010] A magnetocardiogram (MCG for short) is the recording and display of the heart's magnetic field, which is generated by the electrophysiological activity of the heart muscle cells. The invention proposes a contactless, passive method for long-term, high-resolution monitoring of the human heart. This is achieved using at least one nitrogen vacancy magnetometer unit (so-called NV magnetometer unit).

[0011] In detail, a device for detecting magnetic signals generated by a beating heart is now presented, which device has at least one NV magnetometer unit configured to detect a magnetic field strength and field direction, at least one further sensor, and a signal processing unit to which the at least one NV magnetometer unit and the at least one further sensor are connected. The device is configured to use the signal processing unit to determine at least one effective magnetic field strength and / or at least one effective field direction from the signals of the at least one NV magnetometer unit and the at least one further sensor. Both a wireless and a wired connection between the sensor system and the signal processing unit is provided. Such a device can also be referred to as a magnetocardiograph.

[0012] The invention relates to signal processing for magnetocardiographs, particularly but not exclusively related to applications in household environments. The signal processing in this case has the particular task of making the system independent of external magnetic field disturbances. Wherever electrical charges move or magnetic or magnetizable materials are moved, the ambient magnetic field changes, which must be separated from the signal by appropriate signal processing in order to make it measurable. Particularly good signal processing also enables the improvement of signal resolution and thus the detection of rarer and more difficult-to-detect artifacts over time of the cardiac signal or other biomedical signals and associated clinical pictures. This disclosure particularly addresses the advantages of coupling with other sensors and technologies.The at least one further sensor can advantageously be used for signal processing, in particular triggering of averaging, referencing and comparison algorithms.

[0013] A particular advantage of NV sensors is their size, especially of the sensor medium. For the application, the active measuring volume should be small compared to the object to be measured (heart), since otherwise the area coverage would result in integration over large parts of the signal, and thus the signal might disappear because the integral is zero. The smaller the active measuring volume compared to the heart, the better the signal detection. NV sensors have a very small active sensor volume. This small size also allows the sensors to be used in a geometric arrangement. In particular, very high-resolution arrangements are possible due to the very small active sensor volume. This also enables easy integration into building components (walls, ceilings, etc.) or furnishings (furniture, etc.), textiles (clothing, blankets, etc.) or other everyday objects, with numerous options being considered.

[0014] Diamond NV magnetometers are based on the reading of magnetic resonances from specific defect centers in diamond, particularly nitrogen vacancies (NV), which occur as impurities in the carbon lattice of diamond and can also be deliberately introduced. If the NV center is optically excited in the ground state, for example, by irradiating a pump laser beam with a suitable wavelength (in this case in the green wavelength range, e.g., at 532 nm for off-resonance excitation), the electrons are lifted from the triplet ground state to the excited triplet state and relax, emitting fluorescent light in the red wavelength range at 650 - 800 nm (637 nm = zero phonon line). Since the probability for non-spin-conserving transitions from the spin state increases with the spin quantum number m s =±1 is larger, continuous excitation pumping ensures that the NV centers are mostly in the spin state m s=0 hyperpolarized. Between the m s = 0 and m s =±1 spin states in the ground state, there is an energy difference, which in this case is about 2.87 GHz. Therefore, if microwave radiation is irradiated into the diamond in addition to the optical excitation, a dip in the red fluorescence occurs at this resonance frequency of 2.87 GHz, since the spin-polarized electrons are deflected by the microwave field from the m s = 0 in the m s =±1 ground state and from there by the pump light into the m s =±1 excited state. From there, however, mainly non-radiative transitions and weak infrared fluorescence transitions occur via the singlet state, while fluorescence in the red region disappears.

[0015] If an external magnetic field is present, the so-called Zeeman effect causes the splitting of the otherwise equally energetic m s=±1 triplet levels into energetically equidistant Zeeman levels. When the fluorescence is plotted against a frequency spectrum of the microwave excitation, two dips are observed in the fluorescence spectrum, the frequency spacing of which is proportional to the magnetic field strength of the external magnetic field. The magnetic field sensitivity is primarily defined by the minimum resolvable frequency shift and can reach 1 pTA / Hz or less. Since the NV center in single-crystal diamond has four possible arrangements in the crystal lattice, the presence of a directed magnetic field causes the NV centers present in the crystal to react with varying degrees to the external magnetic field depending on their position within the crystal. Ideally, this results in four pairs of fluorescence minima appearing in the spectrum, from whose shape and position relative to each other, both the magnetic field strength (magnitude) and the direction of the external magnetic field can be clearly determined.

[0016] To enable vector magnetic field measurements, the device in one embodiment comprises a device for generating a substantially homogeneous bias magnetic field in the region of the magnetometer units or their sensor media, wherein the bias magnetic fields of different NV magnetometer units are expediently different. This can be a Helmholtz coil arrangement, with at least the sensor medium arranged within the Helmholtz coil arrangement (each magnetometer unit expediently having its own bias field, which improves field determination). Other devices can also be used, such as a simple coil, an elongated coil, permanent magnet solutions such as in a Hallbach array, etc.

[0017] Heart signals have a magnetic signature with an amplitude of (only) picotesla (pT) at a distance of a few centimeters, whereas, for example, the Earth's magnetic field in Central Europe is about 50 pT (microtesla), i.e. a factor of 10 6 stronger. However, even such small field strengths can be resolved with high precision over the long term using the proposed technology. For example, magnetic shielding or gradiometer circuitry can be used for this purpose.

[0018] High-resolution detection of the precise cardiac signal allows for the detection of a variety of diseases, such as permanent atrial fibrillation and paroxysmal atrial fibrillation. This can prevent a heart attack and, subsequently, a stroke (especially after an undetected heart attack). Furthermore, the invention is suitable for the early detection of ST-elevation myocardial infarction, other types of elevation myocardial infarction, pulmonary embolism, AV nodal retrieval tachycardia, ventricular extrasystoles, and even very rare pathogenic diseases such as arrhythmogenic right ventricular tachycardia, which can otherwise only be detected through gene sequencing.

[0019] Only precise resolution of the cardiac signal enables the detection of these pathologies. In the case of highly noisy or poorly resolved signals, the shifts of the heart's various PQRST complexes relative to each other or over time, fluctuations in their amplitude, deformations, or small disturbances cannot be detected. However, the resolution of these criteria is important, as the aforementioned problems can lead to complex confusion (e.g., interpreting an elevated and shifted T wave as an R wave, which, however, frequently occurs in a "healthy" heart) and false alarms. When a gradiometer circuit of at least two NV magnetometer units is used, thus a geometric arrangement of at least two NV magnetometer units, one magnetometer unit is always at a greater distance from the heart (as a relatively weak magnetic field source) than another magnetometer unit.Through gradiometer interconnection, i.e., essentially (vector) subtraction of the measured value, the magnetic field gradient approximately corresponds to the field emanating from the weak source, while significantly stronger background fields (which are essentially the same in both magnetometer units) are eliminated. This eliminates the need for magnetic shielding, making magnetic field measurement possible in everyday environments. The invention is therefore particularly suitable for the unshielded measurement of weak magnetic fields. Technical details of gradiometer solutions that can also be applied within the scope of the present invention are disclosed in DE 102022201690.4 and are intended to be incorporated herein.

[0020] In one embodiment, the device is configured to detect a magnetic field strength and field direction using at least one NV magnetometer unit. A further advantage of NV sensors is the directional or vector information. In contrast to other technologies, this is inherent in NV sensors. Therefore, there is no need to introduce interference through modulation techniques or use less favorable projections, nor is there a need to use multiple separate sensors. Thus, the vector and gradiometric information are available at exactly the same location (diamond size, i.e., single-digit mm). A 3 and below) and not separated by a few centimeters to many centimeters as with other technologies. NV magnetometer units, which can determine not only the field strength but also the direction of the magnetic field, enable improved suppression of the background field and thus better detection of signals that are heavily overlaid by interference.

[0021] In one embodiment, the device is configured to use the at least one further sensor to determine a recurring reference point in the signals from the at least one NV magnetometer unit, to divide the signals from the at least one NV magnetometer unit into individual signal sections based on the reference point, and to determine an effective signal section from the signal sections. This makes it possible, in particular, to average over several heartbeats. In order to be able to resolve heart signals with high precision, it is possible to average over several heartbeats in order to reduce noise. Since a typical heartbeat is slightly irregular, triggering by another sensor, e.g., a pressure sensor or a pulse oximeter, is proposed. Short averaging (e.g., 5-10 cycles) and long averaging (e.g., 100-200 cycles) are possible in order to obtain different information.

[0022] In particular, the joint consideration of the original signals from the at least one NV magnetometer unit, the at least one additional sensor, and / or the effective signal section can also be used for analysis. The at least one additional sensor can also provide a comparison signal or additional signal for directly distinguishing artifacts.

[0023] Furthermore, the at least one additional sensor can also be used to identify additional peaks, e.g., to distinguish an elevated T-wave from an R-peak. In particular, the NV magnetometer unit can precisely resolve the signal curve so that the individual waves are clearly identifiable, and the at least one additional sensor can detect, for example, strong deflections. If an additional "strong deflection" is present, a reference sensor would simply assume a slightly higher pulse, which would not be conspicuous. By comparing the signals from the NV magnetometer unit and the additional sensor, an elevated T-wave (indicating a heart attack), for example, can be clearly detected. Furthermore, signals in the magnetic signature sometimes differ from peaks detected elsewhere, particularly in different measurement channels (vectometry). Here, too, additional features can be easily identified through a corresponding comparison.Furthermore, if an external trigger that does not detect an additional peak is used for averaging, the additional peak can be identified as a significant signal increase of a specific wave, even with long averaging times, since the peak only appears in one of the signals. In devices with arrangements of at least two NV magnetometer units, in practice one NV magnetometer unit or a (gradiometer) arrangement of two NV magnetometer units is typically always particularly close to the heart. Their signal can be used to particular advantage, as it can be assumed that it best reflects the heart's magnetic signal. This signal can be offset against others, for example to create vectorial derivatives (tensiometry). It can also be used to determine which other NV magnetometer units are very far away from the heart and are therefore better used for background determination.In this case, the position of the user, in particular a position that changes over time, can be determined by at least one further sensor, e.g. pressure or force sensors, (or by the magnetic signal itself) in order to adapt the signal processing to the changed position in time.

[0024] Recording breathing (and similar signals) via at least one additional sensor (e.g., a microphone or pressure sensor) also allows for the correction of interference terms, since breathing implies movement, which corresponds to a displacement of the body relative to the NV magnetometer units. Additional information, such as the breathing pattern, can also be obtained in this way to determine sleep apnea or general health status.

[0025] In particular, a calculation rule can be determined using the at least one additional sensor, according to which the at least one effective magnetic field strength and / or at least one effective field direction is then determined from the signals of the at least one NV magnetometer unit. In particular, such a calculation rule can specify the level at which the signals of which NV magnetometer unit are included in the result. For example, the position of the user, as described above, a temperature, e.g., of individual NV magnetometer units, a strength or variance of a background or interference field, etc., can be decisive here.

[0026] The resulting "time-varying" signal processing is also helpful for evaluating the data and qualifying which data should be evaluated - and which should be considered "erroneous", for example because the user has moved too frequently and / or too quickly, etc.

[0027] Temperature monitoring can also help increase safety, e.g. by triggering an emergency shutdown.

[0028] Other external influences, such as temperature, pressure, warmth of another person in bed, etc. can also be detected by at least one additional sensor and thus corrected or used additionally.

[0029] A recommendation can also be derived from the collected data, e.g., "Place the mat a little lower" or "A different pillow would be healthier for you," and issued via an interface, e.g., an app. In particular, it can also be linked to other technologies, such as a smartwatch and its integrated sensors as at least one additional sensor.

[0030] The at least one further sensor can be selected from the group comprising pressure sensor, force sensor, temperature sensor, acceleration sensor, inertial sensor (IMU), gyroscope, pulse oximeter, microphone, magnetometer unit without nitrogen vacancy centers.

[0031] For this application, a sampling rate higher than the cardiac signal is required to resolve it, especially higher than 50 Hz. A range of 200 Hz to 400 Hz is considered particularly advantageous. Higher is always better for resolution, but increases the sensitivity requirements.

[0032] Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings.

[0033] The invention is illustrated schematically in the drawings using exemplary embodiments and is described below with reference to the drawings. Brief description of the drawings

[0034] Figure 1 shows in a schematic block view the essential components of an NV center magnetometer as can be used in the context of the invention.

[0035] Figure 2 shows, in various figures a) to c), each in a schematic block view, possible arrangements of NV magnetometer units of a device for detecting magnetic signals according to one embodiment.

[0036] Figure 3 shows schematically in a side view a user and a device according to an embodiment of the invention.

[0037] Figure 4 schematically shows in three plan views a) to c) possible configurations of arrangements with one or more NV magnetometer units according to embodiments of the invention.

[0038] Figure 5 shows schematically in two side views a) and b) possible configurations of devices with several arrangements with NV magnetometer units and a signal processing unit according to embodiments of the invention.

[0039] Embodiment(s) of the invention

[0040] Figure 1 schematically shows the essential components of an NV center magnetometer. Initially, a diamond 110 with nitrogen vacancies (NV) serves as the sensor medium. The optical excitation of the NV centers can be achieved by a suitable light source 120, such as an LED or a pump laser. For example, a frequency-doubled Nd:YAG laser or a semiconductor laser in the green range of approximately 510-532 nm is suitable, e.g., at 532 nm for off-resonance excitation. Alternatively, LEDs in suitable wavelength ranges can also be used. Depending on the arrangement, the light from the light source 120 can be irradiated into the diamond 110 via suitable optical elements 122, such as mirrors, beam splitters, focusing optics such as lenses, and optionally via fiber optic elements.In addition, the excitation light can be emitted continuously or in pulsed form by the laser, so that, for example, time windows are kept free for interference-free fluorescence light measurement.

[0041] Furthermore, the magnetometer can comprise a microwave source 150 capable of generating an electromagnetic field in the sensor medium over a bandwidth covering the desired resonance frequency, i.e., in the region of the NV centers of the diamond 110. A microwave resonator structure can be used to homogeneously distribute the generated microwaves across the volume of the measurement area in the diamond. The resonator structure or the microwave source 150 is preferably tuned to the frequency of the electron spin resonances. To enable vector magnetometry, an additional static bias magnetic field 140 is generated. This makes the measurement intrinsically vectorial. Various spatial directions in the crystal structure are used for this purpose. A Helmholtz coil, for example, is suitable for generating such a magnetic field 140, in which a substantially homogeneous magnetic field can be generated in a limited area using a pair of coils.

[0042] The resulting fluorescent light 112 from the diamond 110 can in turn be guided via suitable optical elements 134, such as optical filters, beam splitters, lenses, and / or fiber optic elements, to a first photodetector 130, which is sensitive at least in the range of the fluorescence wavelength. The first photodetector 130 can also be arranged directly on the diamond 110. A second photodetector 132 is arranged such that it can detect at least a portion of the excitation light from the light source 120, which can be coupled out, for example, by a beam splitter, a filter, or a partially transparent element. This detector signal 132 of the excitation light can be used as a reference signal, for example, to eliminate background signals and to highlight the resonance signal of interest by modulating the excitation light using a lock-in amplifier.Additionally or alternatively, this reference signal can be used to account for fluctuations in the excitation light. Appropriate circuits 160, such as a preamplifier, a logarithmic amplifier, a lock-in amplifier, signal filters, or others, are thus provided to receive the signals from the first and second photodetectors and preprocess the signals appropriately for further evaluation. Finally, the preprocessed fluorescence signal can be evaluated by a signal processing unit 170, e.g., using a suitable microcontroller or processor, to obtain the desired parameters of the detected magnetic field from the signal, in particular the magnetic field strength and the direction of the magnetic field.

[0043] It is understood that such a device may also include additional units not shown, such as communication units or interfaces for outputting the measurement results. Such a device may also advantageously be integrated into an ASIC or FPGA.

[0044] In order to be usable in an everyday environment, magnetic fields that do not originate from desired weak sources should be eliminated from the measurement as far as possible, especially the Earth's magnetic field in the range of 10' 5 Tesla (a few microtesla). In contrast, cardiac magnetic fields are in the range of 10- 12 Tesla (Picotesla).

[0045] The elimination of background magnetic fields can be achieved by shielding or by a gradiometer arrangement during magnetic field measurement according to exemplary embodiments. Gradiometers are generally sensor units capable of detecting not only the field strength but also the field gradient.

[0046] For this purpose, at least two individual magnetometer units can be used, arranged at spatially different locations. As an example, a sensor unit using two or more NV center magnetometers in a gradiometer arrangement is described below in conjunction with Figure 2. Figure 2 shows, in various figures a) to c), possible geometric arrangements of NV magnetometer units of a device for detecting magnetic signals according to one embodiment. Figure a) shows, in a side view, an arrangement of NV magnetometer units S1, S2, Sn in any arrangement relative to one another in a plane (perpendicular to the plane of the drawing, i.e., only the first row is visible). Figure b) shows, in a side view, two NV magnetometer units S1, S2, whose sensor media are sections of the same diamond crystal 110. Figure c) shows, in a side view, a number (n times m) of NV magnetometer units S11, S21, ..., Sn1 , S12, S22, ... , Sn2, S1 m, ... Snm in any three-dimensional arrangement. Further layers are arranged behind the plane of the drawing, so that overall a type of cubic lattice is formed. At least one NV magnetometer unit (not shown), which is located, for example, in one of the rear layers, is not arranged in the plane (plane of the drawing) in which other NV magnetometer units S11 , S21 , ... , Sn1 , S12, S22, ... , Sn2, S1 m, ... Snm are arranged.

[0047] Furthermore, M denotes a signal source, here a heart, and O denotes an optional surface (in particular body skin) which limits the accessibility to or reachability of the magnetic field source M.

[0048] In embodiments of the invention, more than two NV magnetometer units can form a gradiometer (but at least two). With each additional NV magnetometer unit, the background field can be better determined, and the location and strength of the exciter can be better separated from the background.

[0049] In other embodiments of the invention, two NV magnetometer units can also form a gradiometer, in which case - depending on the number of NV magnetometer units - a total of several gradiometers are formed and record the signal of interest. From this, an effective measurement signal can then be formed, in particular by the signal processing unit, for example by averaging, summation, etc. A distance d between two NV magnetometer units S1, S2, ... or more precisely their sensor media corresponds to the distance between the locations at which magnetic field measurements are carried out simultaneously. As long as the distance between the measurement locations is relatively small, it can be assumed that the strength of an additional background magnetic field B env is approximately the same at both locations. In contrast, the weak magnetic field B of interest will decrease significantly with increasing distance from the magnetic field source M.

[0050] By arranging two NV magnetometer units at different distances and angles from the source or the heart, the background field can be eliminated or determined using vector arithmetic, allowing the small magnetic field of interest to be determined and its source to be characterized (location and orientation). This can be further improved by a distant magnetometer that is far enough away that the weak magnetic field of interest has dropped below the detection threshold. With such a configuration, local changes in the background field can be compensated for by the at least two nearby magnetometers. For this purpose, for example, two NV magnetometer units can be arranged one above the other in an axial gradiometer configuration, so that an NV magnetometer unit of a first layer forms a gradiometer with an underlying NV magnetometer unit of a second, underlying layer.

[0051] Figures 3 to 5 schematically illustrate possible embodiments of the invention and are described comprehensively below. Identical elements are provided with the same reference numerals and will not be described repeatedly.

[0052] In each case, a device 2 for detecting magnetic signals is shown, which in the examples shown comprises a body, such as a support body 1 with a support surface 1a, and at least one arrangement 3 comprising at least one NV magnetometer unit 4, wherein the at least one arrangement 3 is embedded in the body. The device 2 serves to detect magnetic signals generated by a beating heart (M), but can in principle detect all magnetic signals, in particular biosignals, i.e., those emanating from living beings.

[0053] For illustration purposes, the figures each have a coordinate system in the top left corner, with the drawing plane representing the xz-plane and the y-axis running into the drawing plane.

[0054] The body here is a support body 1, which is designed to support a user 20 sitting or lying on the support surface. However, it can also be a part of a building, a piece of furniture, or textile, etc. Figure 3 shows a mattress as the support body 1, which can also be used for long-term monitoring, in particular of magnetic heart signals.

[0055] A device can comprise one or more than one arrangement. The arrangements can also be arranged in a specific geometric configuration, for example, in a line (1D), a plane (2D), or distributed in space (3D). As explained, two NV magnetometer units can always form a gradiometer, whereby—depending on the number of NV magnetometer units—a total of several gradiometers are formed and record the signal of interest. From this, an effective measurement signal can then be formed, particularly by the signal processing unit, for example by averaging, summation, etc.

[0056] Figure 4 shows, in a schematic plan view in different views a) to c), variants 3.a to 3.c of arrangements 3, each with one or more NV magnetometer units 4, each with one or more further sensors 5. The sensors 5 can be, in particular, pressure sensors, pulse oximeters, temperature sensors, electrodes, etc. The NV magnetometer units 4 and / or the sensors 5 of an arrangement 3 can be arranged in a specific geometric arrangement, for example in a line (1D), plane (2D) or distributed in space (3D), as already explained in connection with Figures 2 or 5. In Figure 5, in two side views a) and b), different variants 2.d, 2.d' of a device 2 with two arrangements 3 in the region of an upper side and one arrangement 3 in the region of an underside of a base body 1 are shown.The arrangement further comprises a signal processing unit 11, to which the NV magnetometer units of the arrangements 3 are connected in order to determine one or more effective magnetic field strengths and / or field directions. Furthermore, a communication unit 12 can be provided to connect the device 2 to other devices such as a PC, tablet PC, or smartphone for input and output and operation. The communication unit 12 can, for example, have wired and / or wireless interfaces. In variant 2.d, the signal processing unit 11 and communication unit 12 are also integrated into the base body, and in variant 2.d' they are arranged outside the base body.

[0057] Preferably, the communication unit 12 has an interface to communicate results, e.g. to a cardiologist or relatives or the user.

[0058] An interface can include a Wi-Fi or mobile network interface, for example, to establish internet access. Internet access should ideally meet current security standards regarding encryption, authentication, access restrictions, etc. Connection to a device via Bluetooth, for example, in conjunction with an app, is also conceivable, for example, to establish indirect internet access.

[0059] In one embodiment, an update (software renewal) and / or upgrade (software expansion) is also possible via the interface. For this purpose, software can be made available for download, for example. The device then has appropriate hard disk storage and corresponding software to enable updating or supplementing software modules. Advantageously, software modules for specific diseases or software modules for specific functions are offered. Software modules can each be individually classified as a medical device, if necessary. In one embodiment, the interface can include an interface for (regular) querying of licensing data, e.g., of the aforementioned software modules, as well as for deactivation after license expiration.

[0060] In one embodiment, the interface can also be used to make emergency calls, i.e., be, represent, or include an emergency call interface. In acute cases, the automatic initiation of an emergency call is envisaged. In addition to the emergency call interface, the interface can also include a backup emergency call interface.

[0061] In one embodiment, the interface may include a direct interface to a communications center, for example, directly to a physician / cardiologist / medical assistant (MFA) for transmitting abnormal data sets. Especially for telemedicine, it is important that certain data sets be transmitted to a cardiologist for review via a secure interface.

[0062] In one embodiment, the interface may include an interface to a cloud. To process data sets or to learn from data sets (machine learning on collected data sets), cloud access should be integrated. In this case, it may be important to implement a data anonymization step. A security concept is also advantageous here.

[0063] In one embodiment, the signal processing unit can comprise an analysis unit. During normal use of the device, e.g., as a long-term MKG, a very large amount of data can be generated that can hardly be viewed manually. Therefore, it is advantageous if selected conspicuous data (i.e., data with certain properties) are transmitted through a preliminary analysis. It is understood that such an analysis unit can also be provided externally at the receiver, e.g., all data is transmitted first, and only then are the conspicuous ones selected at the receiver. In one embodiment, the interface can be an interface to a mobile platform, such as an app (user's app, app of multiple users, e.g., family members). In particular, the user, but also family members, can then access a mobile platform to select data, selected information, and a selected user interface. This is also possible for family members or, e.g.,Nursing staff are important for monitoring. The application can also be booked as an add-on for the technology. A security concept and an internet interface are also advantageous here. This also creates a licensing option that allows for the evaluation of a subscription model.

Claims

Claims 1. Device (2) for detecting magnetic signals generated by a beating heart (M), comprising at least one nitrogen vacancy center (NV) magnetometer unit (4) configured to detect a magnetic field strength and / or field direction, at least one further sensor (5), a signal processing unit (170, 11) to which the at least one NV magnetometer unit (4) and the at least one further sensor (5) are connected, wherein the device is configured to determine at least one effective magnetic field strength and / or at least one effective field direction from the signals of the at least one NV magnetometer unit (4) and the at least one further sensor (5) by means of the signal processing unit (170, 11).

2. Device according to claim 1, which is designed to determine a repeating reference point in the signals of the at least one NV magnetometer unit (4) by means of the at least one further sensor (5), to divide the signals of the at least one NV magnetometer unit (4) into individual signal sections based on the reference point and to determine an effective signal section from the signal sections.

3. Device according to claim 1 or 2, which is designed to determine a position of a user by means of the at least one further sensor (5), and to determine one of the at least one NV magnetometer unit (4) as being close to the heart or as being remote from the heart based on the position.

4. Device according to one of the preceding claims, which is designed to determine a calculation rule by means of the at least one further sensor (5) and, in accordance with this, to determine the at least one effective magnetic field strength and / or at least one effective field direction from the signals of the at least one NV magnetometer unit (4).

5. Device according to one of the preceding claims, wherein the at least one further sensor (5) is configured to detect at least one measured variable selected from a heartbeat, an electric field, an oxygen saturation in blood, a pressure, a force, sound, a temperature, an acceleration, a magnetic field strength, a magnetic field direction.

6. Device according to one of the preceding claims, wherein the at least one further sensor (5) is a magnetometer unit without nitrogen vacancy centers.

7. Device according to one of the preceding claims, wherein the at least one NV magnetometer unit (4) has a diamond crystal or a section of a diamond crystal with nitrogen vacancy centers as the sensor medium (110), wherein the device is configured to detect a magnetic field strength and / or field direction by reading out a spin resonance in the sensor medium (110) that is dependent on the magnetic field strength.

8. The device according to claim 7, further comprising at least one excitation light source (120) for radiating light (124) into the sensor medium (110), at least one microwave source (150) for generating a resonant field in the sensor medium, and at least one photodetector (130) for detecting resonance-dependent fluorescent light (112) from the sensor medium (110).

9. Device according to claim 8, wherein at least two NV magnetometer units (4) are assigned the same excitation light source (120) and / or the same microwave source (150).

10. Device according to one of claims 7 to 9, wherein the sensor medium of at least two NV magnetometer units (4) each comprises a section of the same diamond crystal (110).

11. Device according to one of claims 7 to 10, wherein the distance (d) between the sensor media (110) of at least two NV magnetometer units (4) is between 1 and 30 millimeters, preferably between 5 and 20 millimeters.

12. Device according to one of the preceding claims, further comprising a data interface.

13. The device according to claim 12, wherein the data interface comprises at least one interface selected from a WiFi interface, a mobile radio interface, an Internet interface, a direct interface to a communication center, an interface for querying licensing data, an interface to a cloud, an interface to a mobile platform.

14. Device according to claim 12 or 13, which is configured to enable a software update and / or a software upgrade and / or to make an emergency call via the data interface.

15. Apparatus according to any one of the preceding claims, further comprising an analysis unit for selecting data having specific properties from the magnetic signals.

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