Implantable system

Abstract

An implantable system comprises a first implantable medical device (1) comprising a first communication circuitry (13), a second implantable medical device (2) comprising a second communication circuitry (23), and an external device (4, 5, 6) comprising a third communication circuitry (43) configured to transmit first control information to the first implantable medical device (1) by using a physical layer signaling employing oscillating magnetic signals according to a defined communication protocol. The first implantable medical device (1) is operative to at least one of initiate, modify and inhibit a therapeutic function according to said first control information. The second communication circuitry (23) of the second implantable medical device (2) is configured to transmit second control information to the first implantable medical device (1) by using said physical layer signaling employing oscillating magnetic signals and said defined communication protocol.

Description

[0001] Implantable system

[0002] The instant invention generally relates to an implantable system according to the preamble of claim 1 and a method for operating an implantable system.

[0003] An implantable system of the type concerned herein comprises a first implantable medical device comprising a first communication circuitry, a second implantable medical device comprising a second communication circuit circuitry, and an external device comprising a third communication circuitry. The third communication circuitry is configured to transmit first control information to the first implantable medical device by using a physical layer signaling employing oscillating magnetic signals according to a defined communication protocol, wherein the first implantable medical device is operative to at least one of initiate, modify and inhibit a therapeutic function according to the first control information.

[0004] Within an implantable system of the kind described herein a communication in between implantable medical devices shall be facilitated, such as cardiac stimulation devices (for example a pacemaker device or a cardioverter defibrillator), sensor devices, recording devices or other medical devices to be implanted into a patient for providing a therapeutic or diagnostic function. A communication system of this kind may also be denoted as Body Area Network (BAN) system.

[0005] An implantable medical device of the kind concerned herein may for example be a pacemaker, an implantable cardioverter defibrillator, a sensor device such as a bio-sensor for measuring a blood pressure, or a recording device such as a loop recorder to be subcutaneously implanted in a patient. An implantable pacemaker may for example be subcutaneously implanted in a patient and may comprise leads carrying electrodes and extending from a generator unit of the pacemaker device into the patient's heart for example to provide a pacing action in the right ventricle of the heart. Alternatively, an implantable pacemaker device may be designed as a leadless pacemaker not comprising leads, but being directly implanted into the patient's heart, for example in the right ventricle in order to provide for a pacing action.

[0006] A cardioverter defibrillator may serve for monitoring and treating potentially life-threatening arrhythmias in a patient's heart, wherein a cardioverter defibrillator of this kind may for example be implanted subcutaneously and may comprise leads extending into the patient's heart in order to record signals and to inject stimulation energy into the patient's heart for example to provide an electric shock (defibrillation).

[0007] Sensor devices, such as pressure sensors, flow sensors, temperature sensors or the like, may for example be implanted into a blood vessel, such as a vein, in order to provide for a monitoring of relevant parameters in the context of providing a therapy.

[0008] A loop recorder is for example subcutaneously implanted and serves to continuously record information for example about cardiac activity, such as an ECG. A loop recorder may continuously loop its memory and may store particular portions of signals, such that recorded signals may be communicated to an external device for analyzing the signals and for providing a diagnosis.

[0009] There is a desire that medical devices implanted in a patient may communicate with each other in order to allow the medical devices to interact. For example, signals sensed by a pacemaker device or an implanted sensor device may be transmitted to a loop recorder such that the loop recorder may record such signals. In addition, a pacemaker device may receive signals from a sensor device implanted remotely from the pacemaker device in order to take sensing signals of the sensor device into account for controlling a pacing action in the patient's heart. For establishing a communication, approaches exist to create an intra-body network (IBN) linking implanted medical devices with each other such that signals may be exchanged in between the implanted medical devices.

[0010] For example, EP 2 327 609 Bl describes an acoustic communication link in between implanted medical devices for exchanging information in between the implanted medical devices. The acoustic communication link is established to permit wireless communication between the implanted medical devices, wherein transmission parameters may be adapted, such as a sensitivity and a carrier frequency, in order to improve an existing communication link.

[0011] Implantable medical devices may generally sense data which shall be communicated to another implantable medical device and in addition to an external device for further processing. Alternatively or in addition, implantable medical devices may receive configuration data from an external device in order to adapt operation of a particular implantable medical device. For this, a communication needs to be established with the external device.

[0012] In some approaches, a dedicated implantable medical device serves as a hub to provide a communication link to an external device with a dedicated communication concept differing from a signaling employed within the environment of the implantable medical devices. This comes with the drawback that the implantable medical device serving as the hub may exhibit an increased energy consumption, as communication with the external device may be power intensive. In addition, communication with the external device depends on the correct functioning of the implantable medical device serving as the hub, the hub having to implement different communication concepts in order to be able to establish a communication with the external device as well as with other implantable medical devices. Any failure of the dedicated implantable medical device serving as the hub may eliminate communication to the other implantable medical devices.

[0013] US 2006 / 0031378 Al describes a system and method for providing digital data communications over a wireless intra-body network. A physical protocol layer is logically defined with an identifier uniquely assigned to a plurality of implantable devices in an intrabody network. Functions are specified within the physical protocol layer to permit data exchange over a wireless interface. A slave implantable device is activated in response to an activation signal transmitted through the wireless interface by a master implantable device. A wireless communication link is established between the slave implantable device and the master implantable device upon matching of the identifier assigned to the slave implantable device. Data is communicated intra-bodily over the communications link.

[0014] US 2007 / 02083890 Al describes an apparatus and method for an implanted sound sensor wirelessly communicating with an implantable medical device, or with an external monitoring device.

[0015] Generally, the external device shall transmit control information to an implantable medical device such that, according to the control information, the implantable medical device may carry out a therapeutic function. The control information in particular may contain program instructions which are used to program the implantable medical device such that, according to the program instructions, a therapeutic function may be carried out, for example a pacing function. The program instructions herein may for example relate to a stimulation therapy, such as an anti-bradycardia stimulation or an anti-tachycardia pacing (ATP), and may for example contain bounds, such as for example a bound for a ventricular tachycardia (VT) detection zone at which an anti-tachycardia pacing shall be initiated by the implantable medical device.

[0016] Whereas the programming of the (first) implantable medical device is carried out by the external device, which may for example be a programming device and rests outside of the patient, there may be a desire for a more autarkic operation of an arrangement of implantable medical devices subsequent to an initial programming in order to for example allow implantable medical devices to carry out therapeutic functions in a concerted fashion.

[0017] It is an object of the instant invention to provide an implantable system and a method for operating an implantable system which in an easy way allows for a more autarkic functioning of an arrangement of the implantable medical devices subsequent to an initial programming by an external device.

[0018] This object is achieved by means of an implantable system comprising the features of claim 1.

[0019] Accordingly, the second communication circuitry of the second implantable medical device is configured to transmit second control information to the first implantable medical device by using the physical layer signaling employing oscillating magnetic signals and the defined communication protocol, wherein the first implantable medical device is operative to at least one of initiate, modify and inhibit a therapeutic function according to the second control information.

[0020] The external device, which rests outside of the patient and may for example be an external programming device, is used to communicate with implantable medical devices in order to transmit control information containing programming instructions to the implantable medical devices. In particular, the external device is configured, by means of its communication circuitry, to transmit control information to a first implantable medical device by using a physical layer signaling employing oscillating magnetic fields according to a defined communication protocol. The control information may comprise programming instructions, such as instructions relating to particular detection bounds for example for carrying out an anti-bradycardia stimulation or an anti-tachycardia pacing or instructions relating to delays or the like for outputting stimulation signals. According to the control information received by the external device the first implantable medical device is enabled to carry out a therapeutic function, such as an anti-bradycardia stimulation or an antitachycardia pacing.

[0021] In addition, also a second implantable medical device is configured to transmit control information to the first implantable medical device using the same physical layer signaling employing oscillating magnetic signals and the defined communication protocol. Hence, also the second implantable medical device may transmit control information comprising for example programming instructions to the first implantable medical device, such that the second implantable medical device is enabled to control an operation of the first implantable medical device. In particular, the first implantable medical device is operative to initiate, modify or inhibit a therapeutic function according to the control information received from the second implantable medical device.

[0022] In that also the second implantable medical device is configured for transmitting control information comprising programming instructions, for example relating to an antibradycardia stimulation or to an anti-tachycardia pacing, to the first implantable medical device, the implanted arrangement of the first implantable medical device and the second implantable medical device may function independently of the external device in that, subsequent to an initial programming by the external device, an operation of the first implantable medical device may be adapted independently from the external device by means of the second implantable medical device. The second implantable medical device hence is used to program a setting of the first implantable medical device such that a therapeutic function of the first implantable medical device is adapted, in particular initiated, modified or inhibited, by the second implantable medical device.

[0023] The signaling is based on a physical layer signaling using oscillating magnetic fields. The implantable medical devices as well as the external device comprise communication circuitry using e.g. magnetic coils for producing modulated oscillating magnetic fields for establishing a communication in between the implantable medical devices as well as with the external device.

[0024] Within the communication, a common physical layer signaling as well as a common communication protocol is used for communication in between the implantable medical devices and the external device. The physical layer herein denotes a logical layer defining a physical signaling in between the different devices using a common technology according to a common communication protocol. Each implantable medical device as well as the external device may be identified within communication messages by means of a unique identifier, such that messages transmitted through the patient's body are received and processed by the devices according to identifier information included in the messages. The communication protocol may in particular involve a bidirectional communication in between the external device and the implantable medical devices. For example, within the communication protocol the second implantable medical device may identify and authenticate itself with respect to the first implantable medical device for example by using a handshake scheme, wherein the external device and the second implantable medical device use the same protocol to identify and authenticate themselves with respect to the first implantable medical device.

[0025] Within a bidirectional communication the first implantable medical device may acknowledge the reception of control information to the external device or to the second implantable medical device, wherein the first implantable medical device uses the same acknowledgment scheme with respect to the external device and the second implantable medical device.

[0026] Within the implantable system the external device may for example be used to initialize the communication protocol for enabling an authentication, addressing and the like in between the external device and the implantable medical devices. The external device may in particular be used to logically combine an arrangement of implantable medical devices to form an intra-body network which employs a common physical layer signaling using oscillating magnetic signals according to a defined communication protocol.

[0027] The communication protocol may be standardized, for example according to the IEEE 802.15.6 relating to Wireless Body Area Networks (WBAN) aiming to provide an international standard for low power, short range, and reliable wireless communication within the surrounding area of the human body, supporting a large range of data rates for different applications and using existing industrial scientific medical (ISM) bands as well as frequency bands approved by national medical and / or regulatory authorities. A standardized scheme may in particular aim to provide confidentiality, authentication, integrity, privacy protection, and replay defense. For communicating the control information as concerned herein the external device and the implantable medical devices may in particular employ a high order security level, for example out of three security levels, involving authentication and encryption. During a security association process, the external device and the implantable medical devices jointly select a suitable security level. In unicast communication, a pre-shared or a new key (also denoted as master key, in short MK) may be activated. A pairwise temporal key (PTK) may then be generated. In multicast communication, a group temporal key (GTK) may be generated that is shared with the corresponding group. All implantable medical devices and the external device in a WBAN may have to go through certain stages at the MAC layer before data exchange to establish a security association in which the external device and the implantable medical devices are identified to each other.

[0028] In one embodiment, the first implantable medical device is a cardiac stimulation device such as a cardiac pacemaker or an implantable cardioverter defibrillator. The first implantable medical device may in particular be a leadless device, such as a leadless pacemaker device, which is configured for direct implantation into the patient’s heart, for example into a ventricle of the patient’s heart. The first implantable medical device may also be a neurostimulation device, a cardiac contraction regulation device or an implantable drug pump.

[0029] In one embodiment, the second implantable medical device may be a cardiac stimulation device such as a subcutaneous implantable defibrillator, a cardiac monitoring device or a pressure monitoring device. The second implantable medical device may in particular be configured for implantation outside of the patient’s heart, wherein the second implantable medical device may comprise one or multiple leads resting outside of or extending into the heart in order to sense signals relating to cardiac activity and / or output stimulation signals to perform a therapeutic function.

[0030] Generally, one or multiple implantable medical devices of the implantable system may be implanted subcutaneously into a patient or directly into the patient's heart. For example, in one embodiment, one implantable medical device is implanted into the right ventricle and another implantable medical device is implanted into the right atrium of the patient's heart, a communication being established in between the intra-cardiac implantable medical devices within the implantable system. In one embodiment, at least one of the first implantable medical device and the second implantable medical device is a subcutaneous cardiac loop recorder or a bio-sensor for measuring the blood pressure.

[0031] Generally, within the implantable system implantable medical devices e.g. in the shape of stimulation devices, sensing devices, recording devices or marking devices may communicate with one another.

[0032] In one embodiment, the second communication circuitry of the second implantable medical device and the third communication circuitry of the external device each comprise a magnetic transmitting device for producing a modulated magnetic field for carrying out said physical layer signaling employing oscillating magnetic fields according to the defined communication protocol. In turn, the first communication circuitry of the first implantable medical device may comprise a magnetic sensing device for receiving the modulated magnetic field.

[0033] The magnetic transmitting device of the second implantable medical device and / or the external device may for example comprise a magnetic coil for producing a magnetic field. A magnetic coil of this type may have a magnetic core or may not have a magnetic core. In one embodiment, the magnetic transmitting device of the second implantable medical device and / or the external device may comprise multiple magnetic coils for example for producing magnetic fields along different communication planes.

[0034] The magnetic sensing device of the first implantable medical device may for example comprise a magnetic coil for receiving magnetic fields or for establishing an inductive coupling to the magnetic transmitting device of the second implantable medical device and / or the external device. In one embodiment, the magnetic sensing device comprises multiple magnetic coils for sensing magnetic fields along different communication planes. In another embodiment, the magnetic sensing device may comprise one or multiple magnetic sensors, such as GMR sensors, Hall sensors or the like. In one embodiment, the first communication circuitry of the first implantable medical device comprises a magnetic transmitting device for producing a modulated magnetic field for carrying out the physical layer signaling employing oscillating magnetic signals according to the defined communication protocol. In turn, the second communication circuitry of the second implantable medical device and the third communication circuitry of the external device each comprise a magnetic sensing device for receiving the modulated magnetic field. Hence, also the first implantable medical device comprises a magnetic transmitting device enabling the first implantable medical device to transmit signals, for example to establish a bidirectional communication to the external device and / or to the second implantable medical device.

[0035] The magnetic transmitting device of the first implantable medical device, similar to the magnetic transmitting device of the second implantable medical device or the external device, may for example comprise a magnetic coil for producing a magnetic field. A magnetic coil of this type may have a magnetic core or may not have a magnetic core. In one embodiment, the magnetic transmitting device of the first implantable medical device may comprise multiple magnetic coils for example for producing magnetic fields along different communication planes.

[0036] The magnetic sensing device of the second implantable medical device and / or the external device may for example comprise a magnetic coil for receiving magnetic fields or for establishing an inductive coupling to the magnetic transmitting device of the first implantable medical device. In one embodiment, the magnetic sensing device comprises multiple magnetic coils for sensing magnetic fields along different communication planes. In another embodiment, the magnetic sensing device may comprise one or multiple magnetic sensors, such as GMR sensors, Hall sensors or the like.

[0037] In any of the magnetic transmitting and sensing devices, a transmitting magnetic coil may likewise be used as a receiving magnetic coil, such that only a single coil or arrangement of coils may suffice for enabling a transmission and a reception. In another embodiment, in any of the magnetic transmitting and sensing devices different magnetic coils may be used for transmission and reception, wherein the different coils may differ in their size and shape, their number of turns and for example a wire diameter.

[0038] If a transmitting or sensing device comprises multiple magnetic coils, the magnetic coils may be oriented for example orthogonally with respect to each other, such that the magnetic coils enable a communication along perpendicular communication planes. The magnetic coils may electrically be coupled to each other, for example by connecting them in series, such that the arrangement of magnetic coils allows for an omnidirectional communication. Alternatively, it may be switched between the different coils for signal transmission or reception.

[0039] For any of the first implantable medical device and the second implantable medical device, one or multiple magnetic coils may be wound about a component, such as a battery or a capacitor or another component, for example a component having a reduced metal content. One or multiple magnetic coils may be arranged in a space between a component and a housing of the respective implantable medical device, or may be integrated on a carrier element such as a printed circuit board. For example, a magnetic coil may be integrated in a carrier of a dump resistor of a defibrillator.

[0040] In another embodiment, for any of the first implantable medical device and the second implantable medical device one or multiple coils may be arranged outside of a housing of the respective implantable medical device, for example by winding the magnetic coil about a portion of the housing.

[0041] In one embodiment, the third communication circuitry of the external device is configured to transmit, by using the physical layer signaling employing oscillating magnetic signals according to the defined communication protocol, the second control information to the second implantable medical device prior to the second implantable medical device transmitting the second control information to the first implantable medical device. The second control information hence is sent by the external device to the second implantable medical device prior to the second implantable medical device sending the control information to the first implantable medical device. The control information, for example comprising one or multiple sets of programming instructions, hence is provided by the external device to the second implantable medical device, which subsequently, for example immediately after receiving the control information or based on an event occurring in subsequent operation of the implantable system, forwards the control information to the first implantable medical device.

[0042] For example, the external device may send control information comprising two or more than two sets of programming instructions relating to different therapeutic functions, such as an anti-bradycardia stimulation and an anti-tachycardia pacing, to the second implantable medical device, which may then transmit the programming instructions to the first implantable medical device.

[0043] Alternatively or in addition, the second implantable medical device may be configured to generate by itself, independent of the external device, programming instructions and may send the programming instructions as control information to the first implantable medical device. The control information sent from the second implantable medical device to the first implantable medical device in this case hence does not originate from the external device, but is generated by the second implantable medical device.

[0044] In one embodiment, the third communication circuitry of the external device is configured to transmit third control information to the second communication circuitry of the second implantable medical device by using the physical layer signaling employing oscillating magnetic signals according to the defined communication protocol. The second implantable medical device herein is operative to at least one of initiate, modify and inhibit a therapeutic function according to the third control information. The external device hence transmits control information, for example comprising programming instructions, also to the second implantable medical device, which is configured to carry out a therapeutic function according to the control information received from the external device.

[0045] The external device may be a programming device which, for example by a physician, is used on the patient to program implantable medical devices implanted in the patient. In another embodiment, the external device may for example be an external communication device, for example in a home monitoring environment, which is in communicative connection with a cloud-based server and functions as a communication relay for providing programming instructions originating from the server to implantable medical devices.

[0046] In one embodiment, the second implantable medical device comprises an electrode arrangement for sensing signals, wherein the second implantable medical device is configured to derive information with respect to the initiation, modification or inhibition of the therapeutic function by the first implantable medical device based on signals sensed using the electrode arrangement. Generally, when transmitting control information to the first implantable medical device by the external device or by the second implantable medical device, the first implantable medical device may acknowledge receipt of the control information to the external device or the second implantable medical device. In another embodiment, the first implantable medical device may operate, without providing an explicit acknowledgement, according to the control information in that it initiates, modifies or inhibits a therapeutic function, for example by initiating an anti-bradycardia stimulation or an anti-tachycardia pacing. The second implantable medical device may sense information relating to the therapeutic function of the first implantable medical device and hence is acknowledged, by sensing information using the electrode arrangement, that the control information has been received by the first implantable medical device.

[0047] In one embodiment, at least one of the third communication circuitry of the external device and the second communication circuitry of the second implantable medical device is configured to transmit a first magnetic field signal at a first field strength and a second magnetic field signal at a second field strength to the first implantable medical device. The first field strength herein is larger than the second field strength. The field strength in each case may relate to the field strength of a carrier signal at a predefined carrier frequency, for example in between 1 MHz and 50 MHz, wherein the carrier frequency signal is modulated to carry control information.

[0048] By sending different signals at different field strengths, for example initially a wake-up signal may be sent to the first communication circuitry of the first implantable medical device causing the first communication circuitry to enter from a sleep state into an operative state in which the first communication circuitry of the first implantable medical device is enabled to communicate with the external device or the second implantable medical device. Once the wake-up signal has been sent and the first communication circuitry of the first implantable medical device hence is woken up, control information may then be transmitted using the second magnetic field signal at a lower field strength. By transmitting at a lower field strength, for example energy may be saved.

[0049] In one embodiment, at least one of the second communication circuitry of the second implantable medical device and the third communication circuitry of the external device is configured to transmit the first magnetic field signal and the second magnetic field signal in an initial instance at initial first and second field strengths and in a subsequent instance at increased first and second field strengths, wherein a relationship between the first and second field strengths preferably remains constant. Alternatively, at least one of the second communication circuitry of the second implantable medical device and the third communication circuitry of the external device is configured to transmit only the first magnetic field signal in an initial instance at an initial first field strength and in a subsequent instance at an increased first field strength. In yet another alternative embodiment, at least one of the second communication circuitry of the second implantable medical device and the third communication circuitry of the external device is configured to transmit only the second magnetic field signal in an initial instance at an initial second field strength and in a subsequent instance at an increased second field strength. Thus, for instance, if in an initial attempt the transmission of the wake-up signal and the control information from the second implantable medical device to the first implantable medical device fails, the second implantable medical device may repeat transmission of the wake-up signal and the control information at increased field strengths in order to ensure the reception of the control information at the first implantable medical device.

[0050] In another preferred embodiment, in particular in case that an acknowledgment by the first implantable medical device of receiving the control information is unsuccessful or cannot be derived by the second implantable medical device or the external device, respectively, the second implantable medical device or the external device may be configured to control the first and / or second magnetic field strength to be increased stepwise until a reception of the control information by the first implantable medical device is acknowledged successful or can be successfully derived by the second implantable medical device or the external device, respectively.

[0051] If the second implantable medical device is a subcutaneous defibrillator comprising for example an energy storage arrangement comprising for example a multiplicity of capacitors, the energy storage arrangement may provide energy to the second communication circuitry in order to establish a communication with the first implantable medical device.

[0052] In one embodiment, the physical layer signaling may employ oscillating magnetic fields in a frequency range in between 1 MHz and 50 MHz.

[0053] In another aspect, a method for operating an implantable system comprises: providing a first implantable medical device comprising a first communication circuitry; providing a second implantable medical device comprising a second communication circuitry; transmitting, using an external device comprising a third communication circuitry, first control information to the first implantable medical device by using a physical layer signaling employing oscillating magnetic signals according to a defined communication protocol; at least one of initiating, modifying and inhibiting a therapeutic function according to said first control information by the first implantable medical device; transmitting, using the second communication circuitry of the second implantable medical device, second control information to the first implantable medical device by using said physical layer signaling employing oscillating magnetic signals and said defined communication protocol; and at least one of initiating, modifying and inhibiting a therapeutic function according to said second control information by the first implantable medical device.

[0054] The advantages and advantageous embodiments described above for the implantable system equally apply also to the method, such that it shall be referred to the above in this respect. The various features and advantages of the present invention may be more readily understood with reference to the following detailed description and the embodiments shown in the drawings. Herein,

[0055] Fig. 1 shows a schematic drawing of an implantable system of medical devices implanted in a patient;

[0056] Fig. 2 shows a schematic drawing of implantable medical devices and an external device in between which a data communication shall be established;

[0057] Fig. 3 shows a schematic drawing of an implantable system including multiple medical devices implanted in a patient and a variety of external devices;

[0058] Fig. 4 shows a schematic drawing of an embodiment of an implantable medical device in the shape of a leadless pacemaker device having an arrangement of magnetic coils, in a first configuration state;

[0059] Fig. 5 shows a schematic drawing of the implantable medical device of Fig. 4, in a second configuration state of the coil arrangement;

[0060] Fig. 6 shows a schematic drawing of an implantable system in a patient;

[0061] Fig. 7 shows a schematic drawing of another example of an implantable system; and

[0062] Fig. 8 shows a communication scheme for transmitting control information from a second implantable medical device to a first implantable medical device.

[0063] Subsequently, embodiments of the invention shall be described in detail with reference to the drawings. In the drawings, like reference numerals designate like structural elements.

[0064] It is to be noted that the embodiments are not limiting for the invention, but merely represent illustrative examples. Referring to Fig. 1, implantable medical devices 1, 2, 3 may be implanted in a patient P at different locations in order to provide different functions within the patient. For example, a medical device 1 in the shape of a leadless pacemaker device may be implanted in the right ventricle RV of the patient's heart in order to provide for a pacing action within the heart H. Another medical device 2 for example in the shape of a defibrillator may subcutaneously be implanted within the chest. Another implantable medical device 3 in the shape of a sensor device, for example a pressure sensor, a flow sensor or a temperature sensor or the like, may be implanted for example in a blood vessel in order to sense characteristic parameters such as a blood pressure or a blood flow.

[0065] External devices 4, 5, such as an external programming device or a communication device in the context of a home monitoring system, are placed outside of the patient P.

[0066] There generally exists a desire for a data communication in between different medical devices 1, 2, 3 implanted in a patient P and external devices 4, 5 resting outside of the patient P. Approaches exist to establish a communication of this kind in a wireless fashion, such that data may be exchanged in between the medical device 1, 2, 3 and the external devices 4, 5.

[0067] In order to allow for a data communication, signals are exchanged in a modulated fashion making use of a particular transmission technology, namely a magnetic (inductive) signal transmission, and a particular modulation scheme, such as a PCM, FSK, PSK, QPSK, FM, or AM modulation or the like. Transmission generally takes place by employing a carrier frequency, which must match in between the communicating medical devices 1-5 in order to establish reliable communication links.

[0068] Referring now to Fig. 2, medical devices 1, 2 to be implanted in a patient may have a small built and may be designed for a low power consumption in order to remain in a patient over a long-term. A first medical device 1, for example in the shape of a leadless pacemaker, may herein comprise a housing 10, a control circuitry 11, an electrode arrangement 12 for emitting stimulation signals or receiving sense signals, a communication circuitry 13 and an energy storage 14, for example in the shape of a battery.

[0069] A second medical device 2, for example a subcutaneous defibrillator having a lead 22 carrying an electrode arrangement for sensing signals and for outputting stimulation signals, comprises a housing 20, a control circuitry 21, a communication circuitry 23, and an energy storage 24, for example in the shape of a battery.

[0070] An external device 4, for example an external programming device, comprises a communication circuitry 43, processing circuitry and in addition circuitry for establishing for example a communication with a cloud-based server or the like.

[0071] The communication circuitry 13, 23, 43, in each case, comprises a magnetic transmitting device 130, 230, 430 and a magnetic sensing device 131, 231, 431. The communication circuitry 13, 23, 43 is designed for transmitting and receiving magnetic signals. Also, the communication circuitry 13, 23, 43 is designed to modulate respectively demodulate signals for transmission and reception, to optimize transmission parameters, to amplify received signals and to process signals in order to forward processed signals to a control circuitry for an analysis and control of the operation of the medical devices 1, 2.

[0072] In one embodiment, within an implantable system as schematically shown in Fig. 1, a communication in between implantable medical devices 1, 2, 3 and external devices 4, 5 is established using communication links. Referring for example to Fig. 2, communication links L may be established in between the medical devices 1, 2 and / or an external device 4 for example at the initial startup of one of the medical devices 1, 2 or after exiting a sleep mode after a prolonged duration of passivity of the medical device 1, 2. Herein, a medical device 1, 2 or an external device 4 which wishes to establish a communication may for example send out a trigger signal towards the other medical device 2, 1 or the external device 4, the trigger signal indicating that the respective device 1, 2, 4 wishes to establish communication. Referring now to Fig. 3, medical devices 1, 2, 3 implanted in a patient P may establish a communication for transmitting data amongst each other using communication links Ln, L13, L23. Via such communication links Li2,Li3, L23 for example measurement data may be transferred from a sensing device to a recording device, such as a loop recorder, or to a stimulation device, for processing by the receiving device.

[0073] In addition, the medical devices 1, 2, 3 implanted in the patient P may communicate with one or multiple external devices 4, 5 in order to transfer data, for example measurement data, from the medical device 1, 2, 3 towards the external device 4, 5, or to receive configuration data from the external device 4, 5 to adapt operation of the implanted medical device 1, 2, 3. Communication herein takes place via communication links L15, L25, L35, L34 connecting the external devices 4, 5 and the implanted medical devices 1, 2, 3 with each other, wherein in addition the external devices 4, 5 may also communicate with each other via a link L45.

[0074] In order to facilitate communication in between the intra-body medical devices 1, 2, 3 and the external devices 4, 5, it herein is proposed to use a common communication technology for both the internal, intra-body devices 1, 2, 3 and the external devices 4, 5, such that the medical devices 1, 2, 3 may communicate with each other as well as with the external devices 4, 5 using the same communication technology.

[0075] The common communication technology in particular involves a common physical layer signaling and a common communication protocol.

[0076] The implantable medical devices 1, 2, 3 and the external devices 4, 5 may in particular use a signaling technique based on a physical layer signaling using modulated oscillating magnetic fields. For this, the medical devices 1, 2, 3 and the external devices 4, 5 comprise a transducer in the shape of a magnetic coil to induce oscillating magnetic fields.

[0077] One or multiple of the external devices 4, 5 may be placed on the patient's skin and for this may for example be worn by the patient P, as it is the case for the external device 4 in the embodiment of Fig. 3. Communication in between the implantable medical devices 1, 2, 3 amongst each other, in between the implantable medical devices 1, 2, 3 and the external device 4, 5, and in between the external devices 4, 5 amongst each other using the common signaling technique is based on a transmission of modulated signals, wherein the signals may encode identifier information identifying and addressing devices 1-5. Each device 1-5 herein may be identified by a unique identifier, such that messages can be exchanged in between the devices 1-5.

[0078] The communication links as illustrated in Fig. 3 hence are established as logical links, signals generally being transmitted using the patient's body P as a wave guiding medium, such that signals transmitted from one device 1-5 generally are received by all devices 1-5 coupled within the network, but may be discerned according to identifier information encoded in the signals.

[0079] In the embodiment of Fig. 3, the external devices 4, 5 are configured to communicate with a remote system 6, for example a remote server system within a public communications network, such as the Internet. For example, data may be transmitted from one or both of the external devices 4, 5 to the remote system 6, and may be received from the remote system 6 at the external devices 4, 5.

[0080] The implantable medical devices 1, 2, 3 within the implantable system may for example be cardiac stimulation devices, such as a leadless pacemaker devices or cardioverter defibrillators, sensing devices such as biosensors for example for sensing a blood pressure, or recording devices such as a loop recorder.

[0081] Generally, the implantable medical devices 1, 2, 3 may be implanted fully or in part directly into the patient's heart, for example the right ventricle or the right atrium. In another embodiment, the implantable medical devices 1, 2, 3 may be implanted fully or in part subcutaneously within the patient.

[0082] Referring now to Figs. 4 and 5, in one embodiment a communication circuitry 13 of an implantable medical device 1 may comprise an arrangement of magnetic coils 132, 133 for generating a (predominantly) magnet field M and for establishing an inductive coupling to another implantable medical device 2, 3 and / or to an external device 4, 5.

[0083] In order to allow for a communication in between implantable medical devices 1, 2, 3 and external devices 4, 5 of the implantable system, it is required that signals transmitted from an implantable medical device 1, 2, 3 may be received by another implantable medical device 1, 2, 3 or an external device 4, 5 with sufficient signal quality. For this, signals in one embodiment may be transmitted by an implantable medical device 1, 2, 3 using a magnetic coil arrangement having a substantially omni-directive radiation pattern, hence transmitting signals in all directions alike. Likewise, another implantable medical device 1, 2, 3 may have a magnetic sensing device, for example a coil arrangement, having an omni-directive radiation pattern for omnidirectionally receiving signals.

[0084] The magnetic coils 132, 133 each may for example be formed by a coil element formed by a wound wire or by a coil element formed on a printed circuit board. The magnetic coils 132, 133 may be placed within the housing 10 or may be wound about a housing portion outside of the housing 10 and are configured to transmit and / or receive predominantly magnetic signals M.

[0085] Herein, the magnetic coils 132, 133 are arranged such that a signal transmission and / or reception is established predominantly along a communication plane Cl using the magnetic coil 132 (Fig. 4) and a signal transmission and / or reception is established predominantly along a perpendicular communication plane C2 using the magnetic coil 133 (Fig. 5). A combined radiation pattern may be substantially omnidirectional.

[0086] For communicating with another implantable medical device 2, 3, different magnetic coils 132, 133 may be used in order to establish, in one embodiment, different configuration states having different directional communication characteristics for transmitting or receiving a predominantly magnetic field M. E.g., for communicating with a particular one of the other implantable medical devices 2, 3, one of the configuration states may be chosen, in particular that configuration state which allows for a directive signal transmission towards or reception from the particular other implantable medical device 2, 3. The selection of the configuration state may take place in an initialization phase, during which the implantable medical device 1 may scan through the available configuration states and may identify that configuration state which allows for a most efficient communication. Once the most suitable configuration state is identified, that configuration state is selected for further communication with the particular implantable medical device 2, 3, such that in later operation a communication may be established using the selected configuration state.

[0087] In another embodiment, the magnetic coils 132, 133 may for example be connected in series in order to provide for a substantially omnidirectional coil arrangement.

[0088] Referring now to Fig. 6, in an implantable system an external device 4 shall be configured, using its communication circuitry 43, to transmit control information to a first implantable medical device 1, for example a leadless pacemaker device implanted directly into the patient’s heart H, as it is schematically shown in Fig. 7. The external device 4 herein shall communicate the control information to the implantable medical device 1 using a physical layer signaling employing oscillating magnetic signals according to a defined communication protocol, the control information comprising for example programming instructions to initiate, modify or inhibit a therapy function of the implantable medical device 1, for example to initiate, modify or inhibit an anti -bradycardia stimulation or an anti- tachycardia pacing (ATP) function.

[0089] In addition, a second implantable medical device 2, for example a subcutaneous defibrillator, is configured, with its communication circuitry 23, to transmit control information to the first implantable medical device 1 using the same physical layer signaling employing oscillating magnetic signals according to the same defined communication protocol as used by the external device 4. Hence, also the second implantable medical device 2 is enabled to transfer control information for initiating, modifying or inhibiting a therapy function to the first implantable medical device 1.

[0090] The second implantable medical device 2 herein may function as a relay for transmitting the control information to the first implantable medical device 1. For this, the external device 4 may first transmit the control information to the second implantable medical device 2, upon which the second implantable medical device 2 forwards the control information immediately or on the occurrence of a particular event to the first implantable medical device 1.

[0091] The control information herein may relate to one or multiple sets of programming instructions relating to one or multiple different therapy functions, for example an antibradycardia stimulation function and an anti-tachycardia pacing function. Different sets of programming instructions for controlling operation of the first implantable medical device 1 may be forwarded by the second implantable medical device 2 on the occurrence of specific scenarios, for example dependent on a sensing and processing of cardiac signals at the implantable medical device 2.

[0092] In addition, the external device 4 may transfer control information to the second implantable medical device 2 for controlling a therapy function of the second implantable medical device 2.

[0093] Alternatively or in addition to functioning as a relay, the second implantable medical device 2 may be configured to generate control information comprising programming instructions independent of the external device 4 and may transmit the control information to the first implantable medical device 1. Such programming instructions may in particular relate to a concerted operation of the first implantable medical device 1 and the second implantable medical device 2 to provide for a particular therapy together.

[0094] For example, the second implantable medical device 2 may sense and process signals and may send a control command to the first implantable medical device 1 if, based on the processing of sensed signal, the first implantable medical device 1 shall carry out an antibradycardia stimulation therapy or an anti-tachycardia pacing therapy. The second implantable medical device 2 hence controls the first implantable medical device 1 for initiating a specific therapy.

[0095] In another embodiment, the second implantable medical device 2 may send control information to adjust one or multiple programming parameters of the first implantable medical device 1. For example, the second implantable medical device 2 may transmit information relating to a ventricular tachycardia detection zone to the first implantable medical device 1. If the second implantable medical device 2 is a defibrillator and the first implantable medical device l is a leadless pacemaker, the second implantable medical device 2 may in particular set the ventricular tachycardia detection zone boundary for performing an anti-tachycardia pacing at the first implantable medical device 1 to a value (in bpm relating to a tachycardic heart rate) below the detection zone boundary at the second implantable medical device 2 for performing a defibrillation shock therapy, such that it is ensured that a detection boundary at the first implantable medical device 1 is below a detection boundary at the second implantable medical device 2.

[0096] In yet another embodiment, the second implantable medical device 2 may send control information to inhibit a therapy function at the first implantable medical device 1. For example, if a defibrillation shock therapy by the second implantable medical device 2 is found to be successful and subsequent to the shock therapy a heart rate at a normal rate is detected, an anti-bradycardia stimulation of the first implantable medical device 1 may be inhibited. If in contrast subsequent to a defibrillation shock therapy by the second implantable medical device 2 it is found that an anti-bradycardia stimulation is required, the second implantable medical device 2 may send a control command to the first implantable medical device 1 to initiate an anti-bradycardia stimulation by the first implantable medical device 1.

[0097] Referring now to Fig. 7, a second implantable medical device 2, for example a subcutaneous defibrillator, may be subcutaneously implanted in a patient P. First implantable medical devices 1, 3 A, 3B may for example be implanted directly into the patient’s heart’s H and may for example be leadless pacing devices, wherein a control device 3C for one or multiple of the implantable medical devices 1, 3 A, 3B may rest outside of the patient’s heart H.

[0098] The control information is transmitted by the second implantable medical device 2 to the first implantable medical device 1 by using a physical layer signaling employing modulated magnetic fields and a specified communication protocol. The external device 4 and the second implantable medical device 2 herein use the same physical layer signaling and the same communication protocol to transmit information to the first implantable medical device 1.

[0099] Referring now to Fig. 8, in one embodiment the second implantable medical device 2 may function using logical channels 25, a first channel 250 relating to a transmit channel and a second channel 251 relating to a sense channel. Likewise, the first implantable medical device 1 may function according to logical channels 15, a first channel 150 relating to a therapy channel and a second channel 151 relating to a sense channel.

[0100] For example, to transfer control information from the second implantable medical device 2 to the first implantable medical device 1, the second implantable medical device 2 transmits, on its transmit channel 250, signals SI, S2 towards the first implantable medical device 1 using the physical layer signaling according to the defined communication protocol. Herein, an initial signal SI may be a wake-up signal which shall cause the communication circuitry 13 of the first implantable medical device 1 to wake up, i.e., to enter into an operative state from a prior sleep state. Subsequently, a signal S2 comprises the control information which shall control operation of the first implantable medical device 1.

[0101] As visible from Fig. 8, the wake-up signal SI may be sent at an increased field strength in comparison to the signal S2 comprising the control information.

[0102] If subsequently to transmitting the signals SI, S2 no related response is detected within a waiting period W on the sense channel 251, the second implantable medical device 2 repeats transmission by now transmitting signals ST, S2’ each at an increased field strength in comparison to the signals SI, S2 at the prior instance.

[0103] If the signals ST, S2’ now are properly received and processed by the first implantable medical device 1, control information CI is extracted from the modulated signal S2’ on the logical sense channel 151 and is processed at the first implantable medical device 1 for example to initiate a corresponding therapy function T, which subsequently is output via the therapy channel 150. The outputting of the therapy function T is sensed on the sense channel 251 by the second implantable medical device 2, such that an acknowledgment ACK is identified at the second implantable medical device 2.

[0104] In the example of Fig. 8, a unidirectional communication from the second implantable medical device 2 to the implantable medical device 1 may be sufficient. An acknowledgment ACK is obtained by the second implantable medical device 2 by sensing signals relating to cardiac activity and stimulation signals output by the first implantable medical device 1 during a therapy function T. An explicit acknowledgment message hence is not required by the first implantable medical device 1.

[0105] The idea underlying the invention is not limited to the embodiments described above, but may be implemented in an entirely different fashion.

[0106] A first implantable medical device may be a cardiac stimulation device, a neuro- stimulation device or and another implantable medical device for performing a stimulation function. In particular, the first implantable medical device may be a leadless pacemaker device.

[0107] The second implantable medical device may be a cardiac stimulation device or a neurostimulation device, for example a defibrillator device configured for implantation outside of the patient’s heart.

[0108] By establishing a control of one implantable medical device by another implantable medical device, implantable medical devices may function in a concerted fashion, such that a therapy function by one device may be aligned with a therapy function of another device. LIST OF REFERENCE NUMERALS

[0109] I, 2, 3, 3A-3C Implantable medical device

[0110] 10, 20 Housing

[0111] I I, 21 Control circuitry

[0112] 12, 22 Electrode arrangement

[0113] 13, 23 Communication circuitry

[0114] 130, 230 Magnetic transmitting device

[0115] 131, 231 Magnetic sensing device

[0116] 132, 133 Magneti coils

[0117] 14, 24 Energy storage

[0118] 15, 25 Channels

[0119] 150 Therapy channel

[0120] 151 Sense channel

[0121] 250 Transmit channel

[0122] 251 Sense channel

[0123] 4, 5, 6 External device

[0124] 43, 23 Communication circuitry

[0125] 430 Magnetic transmitting device

[0126] 431 Magnetic sensing device

[0127] ACK Acknowledgement

[0128] Cl, C2 Communication plane

[0129] CI Control information

[0130] E4, E5 External link

[0131] H Heart

[0132] L Communication link

[0133] L12-L45 Communication links

[0134] M Predominantly magnetic field

[0135] P Patient

[0136] RV Right ventricle

[0137] SI, S2, SI’, S2’ Signal

[0138] T Therapy function w Waiting period

Claims

Claims1. An implantable system, comprising: a first implantable medical device (1) comprising a first communication circuitry (13); a second implantable medical device (2) comprising a second communication circuitry (23); and an external device (4, 5, 6) comprising a third communication circuitry (43) configured to transmit first control information to the first implantable medical device (1) by using a physical layer signaling employing oscillating magnetic signals according to a defined communication protocol, wherein the first implantable medical device (1) is operative to at least one of initiate, modify and inhibit a therapeutic function according to said first control information; characterized in that the second communication circuitry (23) of the second implantable medical device (2) is configured to transmit second control information to the first implantable medical device (1) by using said physical layer signaling employing oscillating magnetic signals and said defined communication protocol, wherein the first implantable medical device (1) is operative to at least one of initiate, modify and inhibit a therapeutic function according to said second control information.

2. The implantable system according to claim 1, characterized in that the first implantable medical device (1) is a cardiac stimulation device such as a cardiac pacemaker or an implantable cardioverter defibrillator, a neurostimulation device, a cardiac contraction modulation device, or an implantable drug pump.

3. The implantable system according to claim 1 or 2, characterized in that the second implantable medical device (2) is a cardiac stimulation device such as a subcutaneous implantable defibrillator, a cardiac monitoring device or a pressure monitoring device.

4. The implantable system according to one of claims 1 to 3, characterized in that the second communication circuitry (23) of the second implantable medical device (2) and the third communication circuitry (43) of the external device (4, 5, 6) each comprise amagnetic transmitting device (230, 430) for producing a modulated magnetic field for carrying out said physical layer signaling employing oscillating magnetic signals according to said defined communication protocol, and the first communication circuitry (13) of the first implantable medical device (1) comprises a magnetic sensing device (131) for receiving said modulated magnetic field.

5. The implantable system according to one of the preceding claims, characterized in that the first communication circuitry (13) of the first implantable medical device (1) comprises a magnetic transmitting device (130) for producing a modulated magnetic field for carrying out said physical layer signaling employing oscillating magnetic signals according to said defined communication protocol, and the second communication circuitry (23) of the second implantable medical device (2) and the third communication circuitry (43) of the external device (4, 5, 6) each comprise a magnetic sensing device (231, 431) for receiving said modulated magnetic field.

6. The implantable system according to claim 4 or 5, characterized in that the magnetic transmitting device (230, 430) comprises at least one magnetic coil.

7. The implantable system according to one of claims 4 to 6, characterized in that the magnetic transmitting device (230, 430) comprises multiple magnetic coils configured to transmit magnet signals along different communication planes (Cl, C2).

8. The implantable system according to one of the preceding claims, characterized in that the third communication circuitry (43) of the external device (4, 5, 6) is configured to transmit, by using said physical layer signaling employing oscillating magnetic signals according to said defined communication protocol, said second control information to the second implantable medical device (2) prior to the second implantable medical device (2) transmitting the second control information to the first implantable medical device (1).

9. The implantable system according to one of the preceding claims, characterized in that the third communication circuitry (43) of the external device (4, 5, 6) is configuredto transmit third control information to the second communication circuitry (23) of the second implantable medical device (2) by using said physical layer signaling employing oscillating magnetic signals according to said defined communication protocol, wherein the second implantable medical device (2) is operative to at least one of initiate, modify and inhibit a therapeutic function according to said third control information.

10. The implantable system according to one of the preceding claims, characterized in that the second implantable medical device (2) comprises an electrode arrangement (22) for sensing signals, wherein the second implantable medical device (2) is configured to derive information with respect to the initiation, modification or inhibition of said therapeutic function by the first implantable medical device (1) based on signals sensed using the electrode arrangement (22).

11. The implantable system according to one of the preceding claims, characterized in that at least one of the third communication circuitry (43) of the external device (4, 5, 6) and the second communication circuitry (23) of the second implantable medical device (2) is configured to transmit a first magnetic field signal at a first field strength and a second magnetic field signal at a second field strength to said first implantable medical device (1), wherein the first field strength is larger than the second field strength.

12. The implantable system according to claim 11, characterized in that the first magnetic field signal is a wake-up signal causing the first communication circuitry (13) of the first implantable medical device (1) to transition from a sleep state into an operative state and the second magnetic field signal comprises control information transmitted using said physical layer signaling employing oscillating magnetic signals according to said defined communication protocol.

13. The implantable system according to one of the preceding claims, characterized in that the physical layer signaling employs oscillating magnetic signals in a frequency range between 1 MHz and 50 MHz.

14. A method for operating an implantable system, comprising: providing a first implantable medical device (1) comprising a first communication circuitry (13); providing a second implantable medical device (2) comprising a second communication circuitry (23); transmitting, using an external device (4, 5, 6) comprising a third communication circuitry (43), first control information to the first implantable medical device (1) by using a physical layer signaling employing oscillating magnetic signals according to a defined communication protocol, wherein the first implantable medical device (1) is operative to at least one of initiate, modify and inhibit a therapeutic function according to said first control information; and characterized by transmitting, using the second communication circuitry (23) of the second implantable medical device (2), second control information to the first implantable medical device (1) by using said physical layer signaling employing oscillating magnetic signals and said defined communication protocol; wherein the first implantable medical device (1) is operative to at least one of initiate, modify and inhibit a therapeutic function according to said second control information.

15. The method according to the preceding claim, further comprising: at least one of initiating, modifying and inhibiting a therapeutic function according to said first control information by the first implantable medical device (1); and at least one of modifying and inhibiting the therapeutic function according to said second control information by the first implantable medical device (1).

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