Implantable medical device with mobile wireless modem

p0001The invention relates to a dauerimplantierbares electronic implant which is adapted to detect at least one technical or physiological parameters. In particular, the invention relates to implantable pulse generators such as pacemakers, cardioverter / defibrillators, or the like.

p0002The remote monitoring of electronic implants such as pacemakers, implantable defibrillators or Neurostimulators becoming increasingly important. These implants transmit it periodically (eg. As once a day) or event-triggered data to a remote monitoring server that is accessible to turn over a data link to the doctor and so can perform remote monitoring.

p0003All currently known solutions have to rely on a relay station (z. B. BIOTRONIK Cardio Messenger) for transmitting the data from the electronic implant to a data transmission network (mobile network, telephone network, etc.). Preference here is a transfer of data from the electronic implant to the relay station via the MICS band (eg. T. also ISM band) used.

p0004Disadvantage of this solution is that the patient must carry an additional, costly additional external device in range of the implant, so as to ensure data transmission from the implant to the transmission network. These external accessories are also therefore be regarded as a weakness of this transmission chain, as these are often not correctly controlled by the patient or are not in range of the implant (patient compliance). ZT encounter these devices also rejected by the patient and have psychological side effects, since the patient is constantly reminded of the electronic implant (anxiety, compulsion to control, etc.).

p0005<figref idrefs="f0001">figure 1</figref> shows the current state of technology. An electronic implant 110 has a MICS-band transceiver and sends in periodic intervals signals, the values ​​of technical and / or physiological parameters represent and which were measured with the implant, to a relay station 120 in the immediate vicinity of the patient electronic with the implant must be located at the transfer date. This relay station 120 then transmits by means of an integrated GSM modem, the transmitted data to a GSM base station 130, which in turn transmits the data over a mobile radio network 140 to a remote monitoring server 150, and thus the doctor 160 is available.

p0006The relay station 120 - called patient device - can be implemented in a mobile or stationary version. Alternatively, a fixed telephone connection for data transmission used in an inpatient unit.

p0007A safe data transfer is only possible if the patient device 120 is turned on and in a maximum of 2-5 meters distance is the electronic implant.

p0008The invention has for its object to realize a data connection for remote monitoring of an electronic implant between the implant and a cellular network (eg. As a GSM network) without an additional relay station.

p0009This object is achieved by a dauerimplantierbares electronic implant, which is designed to detect at least one technical or physiological parameters, and which one is exhaustive current or voltage source, ie generally a battery having. The electronic implant has a poor current cellular modem with a low maximum transmission power, which is connected with a built-in electronic implant mobile radio antenna. The information "stromarm" and "low maximum transmission power" are intended for better understanding of the relationship and reflect today's standard GSM modem for data transmission. In addition, the implant has a connection with this antenna or a second antenna current starved mobile field strength measuring unit and a control unit which is connected to the field strength measurement unit and the cellular modem. The control unit is formed, a dial in a mobile network, depending<ul><li>both in consideration of a current output value of the field strength measurement unit (ie a current field strength value) </li><li>as well as the urgency of data to be transmitted content</li></ul>only trigger if the current output value of the field strength measurement unit indicates a specific for a particular urgency minimum transmission success rate.

p0010In a simple case, this may mean, for example, that the control unit has a dial only triggers when the amount estimated as necessary in consideration of certain of the field strength measuring unit mobile field strength value transmission power does not exceed a specific for a particular urgency maximum.

p0011Here, the integration of a GSM modem will be provided in an electronic implant to be known (see: <patcit id="pcit0001" dnum="US20070032832A1"><text>US 2007/0032832 A1</text></patcit>), Wherein the out <patcit id="pcit0002" dnum="US20070032832A1"><text>US 2007/0032832 A1</text></patcit> known solution to the exhaustion of the battery of an electronic implant duration takes no account. By contrast, allows the solution of the invention to operate a cellular modem in an electronic implant so stromarm, which is measured at the expected operating time reduction justified by the data transmission its use.

p0012The invention is based on the assumption that the support of an electronic implant in the future always is in the area of ​​mobile radio cells, for example, GSM cells, which consist one or more times a day also above average transmission and reception conditions. This should be exploited by the invention and only in these conditions, the connection should be established to a mobile phone base station at all.

p0013For patients in whom this assumption is not correct, Micro-GSM cells are in future expected so-called. Offered for use in the home environment of the GSM operators.

p0014Preferably, the cellular modem, a GSM modem and the mobile field strength measurement unit is a GSM-field strength measurement unit. The electronic implant preferably contains a Subscriber Identity Module, for example in the form of a SIM card.

p0015According to a preferred embodiment further includes the electronic implant a statistics unit, which part is connected to the control unit or the same and formed an access success statistics triggered a elections in response to a respective part of the mobile radio field strength measurement unit measured against a respective dial test field strength value recorded , Here, the control unit can be configured, in addition initiate a dial-up taking into account the access success statistics for each measured mobile field strength value.

p0016Further, the statistical unit may be configured to record the access success statistics taking account of its dial-timing and that the control unit is configured using the access success statistics to determine the timing of a next dial time window and / or field strength measurement window. Thus, the frequency of successful connection setup can be increased with recurring environmental conditions (eg. As good GSM reception in the workplace). Also, the energy required for the determination of the transmission conditions can be reduced by a respective field strength measurement.

p0017In particular, the controller may be configured to determine the respective maximum value for a required transmission power by evaluating the access success statistics depending on the urgency of each data to be transmitted contents, so that, for example, an emergency message is transmitted even in bad transmission conditions, while a less relevant message only at a very cheap sending condition is transmitted.

p0018According to other preferred embodiments, the electronic implant to two current or voltage sources, one of which is determined independently of other units of the electronic implant for the supply of a mobile unit and a (preferably transcutaneous and wireless) rechargeable battery is formed. The mobile unit comprises in this embodiment, preferably at least the cellular modem and can for example also include the mobile field strength measuring unit.

p0019Preferably, the electronic implant has in addition to the mobile field strength measuring unit a very nonspecific GSM field strength detector, which is directly or by means of the control unit configured to activate the mobile field strength measuring unit only when the very nonspecific GSM field strength detecting a minimum field strength ( threshold) indicates. The electronic implant can this have an amplifier, a comparator for threshold comparison and trigger unit for activating the field strength measurement unit when the threshold is exceeded.

p0020The control unit is preferably adapted to a maximum of one access attempt within an adjustable period, z. B. someday trigger.

p0021In addition, the control unit may be adapted to restrict the number of dialing attempts within a respective period of time such that only a predetermined maximum ratio (z. B. 25%) the capacity of the exhaustible current or voltage source for a transmission of data by means of the mobile radio modems are consumed. Here, the control unit may be configured to initiate a dial-up in the case of content data containing emergency messages regardless of the capacity of the exhaustible current or voltage source.

p0022Furthermore, the control unit can be configured to trigger a dial in a mobile network for data content that is generated by a part of the electronic implant detected technical or physiological event. This may be an emergency messages that are triggered by the detection of dangerous to health contemplative states z. B..

p0023The control unit may also be designed so that it triggers a dial on an emergency number data content only in case of emergency messages containing.

p0024The invention will now be explained in more detail using an exemplary embodiment with reference to the figures. Of these shows:<dl id="dl0001"><dt>Fig. 1:</dt><dd>the prior art;</dd><dt>Fig. 2:</dt><dd>The inventive solution as a complete system;</dd><dt>Fig. 3:</dt><dd>a block diagram of an electronic implant with integrated GSM modem; </dd><dt>Fig. 4:</dt><dd>a two-step GSM field strength detector;</dd><dt>Fig. 5:</dt><dd>the block diagram of an alternative implementation; and</dd><dt>Fig. 6:</dt><dd>to in the description <figref idrefs="f0003">figure 3</figref> mentioned transmission success statistics.</dd></dl>

p0025In <figref idrefs="f0002">figure 2</figref> The inventive solution is shown as part of an overall system. This includes an electronic implant 210, in which a GSM modem is integrated, that is controlled by a control unit always dials in a GSM base station 230 when the GSM band field strength makes a low-current dial and data transmission is likely. The further transmission chain with mobile network 240, remote monitoring server 250 to the doctor 260 is unaffected by the invention.

p0026In <figref idrefs="f0003">figure 3</figref> is shown with an integrated GSM modem is a block diagram of an electronic implant. In a hermetically sealed housing 300 of the electronic implant a current poor GSM modem 310 including a SIM module 315 is integrated. A control unit 360 controls the cellular modem 310. The cellular modem 310 is connected to a GSM antenna 340th At the GSM antenna 340 an extremely energy poor GSM-field strength detector 330 is connected as a field strength measurement unit with programmable trigger threshold over a matching network 350th This GSM-field strength detector is also connected to the control unit 360th The control unit is in turn connected to a message scheduler 370th

p0027Further, the electronic implant includes a diagnosis and therapy control unit 380. This diagnosis and therapy control unit 380 is connected to the message scheduler 370 so triggered by diagnostic or therapeutic events of the message Sc heduler 370 can be influenced. This in turn is designed to request both event-triggered and periodic message transmissions. If such a message request, the control unit 360 is activated. This then activates periodically the field strength detector 330 to detect a time when a GSM connection with low output power can be produced. Reports of the field strength detector 330 a suitable starting condition (z. B. if it measures a sufficient mobile field strength), activates the control unit 360, the GSM modem 310 to dial into the base station with the identification data of the SIM module 315. The output of the GSM modulus is adapted to the signal conditions and compared to conventional GSM modems significantly lower.

p0028In addition, this arrangement includes a statistics unit 320 for the statistical monitoring of the transmission success. These statistics unit 320 detects always the transmission success rate based on the measured before connecting GSM-field strength. This statistical detection is preferably carried out as a 3-dimensional histogram in which the third dimension represents the time of day. So it is possible to detect transmission conditions that recur at certain times (eg. As in the office, etc.). The temporal detection may alternatively be extended to a whole week.

p0029The controller 360 in turn includes a unit for classification of the urgency of the message. Here z. B. between routine messages (eg. Remote follow-up data), messages of medium urgency (z. B. VF with successful treatment) and emergency messages (eg. B. unsuccessful maximum energy shock in ICD) is discriminated. Depending on the particular in this classification unit urgency a different transmission success rate is required before establishing the connection of controllers.

p0030In <figref idrefs="f0004">figure 4</figref> is shown according to a preferred embodiment, a two-step GSM field strength detector. The aim is to realize an extremely low-current detector. For this reason, this GSM-field strength detector has a first broadband detector stage 410, 420, 430, which serves as a nonspecific GSM field strength detector. The antenna 400 is connected to a broadband input network 410th After the GSM signal amplification by an amplifier 420, the signal strength of a programmable trigger unit 430 is provided which performs a threshold value by means of an integrated comparator and possibly trigger an activation signal. Since input network 410, the amplifier 420 and the trigger unit 430 form the first broadband detector stage as nonspecific GSM field strength detector only when the input signal exceeds a programmable threshold for a certain time, a second specific frequency selective GSM field strength detector stage enabled, as GSM field strength measurement unit 440 is used. This is connected via a corresponding frequency selective network 450 with the GSM antenna.

p0031The frequency-selective GSM field strength measurement unit 440 checks in addition to the field strength more specific signal characteristics z. B. a respective signal-to-noise ratio in order to increase the likelihood of successful GSM dial. Are these tests positive, then a corresponding output signal is generated.

p0032Below will be shown that the application of the inventive solution, the application of a GSM modem in an electronic implant the example of an implantable cardioverter / defibrillator (ICD) is possible:<ul><li><u>(A) prior art:</u> Battery capacity: ~ 2.3 Ah at an operating voltage of 3V Type. Operating time of an ICD: 6 years<dl id="dl0002" compact="compact"><dt>Data transmission scheme for remote monitoring:</dt><dd>1 access attempt / day + 5 event messages / year</dd></dl>Electricity needs with "standard GSM dial (z. B. GPRS)"<dl id="dl0003" compact="compact"><dt>Dial Duration:</dt><dd>to 10sec</dd><dt>Power consumption at an operating voltage of 3V:</dt><dd>to 1 A</dd></dl>Charge for remote monitoring = 370 dialins * 6 years * 10sec * 1A = 6.1 Ah Ie. With currently available dial-up protocol is not possible a GSM solution.</li><li><u>(B) Inventive solution:</u> Battery capacity: ~ 2.3 Ah at an operating voltage of 3V Type. Operating time of an ICD: 6 years<dl id="dl0004" compact="compact"><dt>Data transmission scheme for remote monitoring:</dt><dd>1 access attempt / day + 5 event messages / year</dd></dl>Electricity demand with "field strength-dependent GSM dial"<dl id="dl0005" compact="compact"><dt>Dial Duration:</dt><dd>to 3 sec</dd><dt>Power consumption at an operating voltage of 3V:</dt><dd>to 0.25 A</dd></dl>Charge for remote monitoring = 370 dialins * 6 years * 3sec * 0.25A = 0.5 Ah With the inventive solution is a GSM dial the implant possible. The battery load is unaltered transmission scheme at 20% capacity. This need for the file transfer battery capacity is in the order of the expected in the years to increase the battery capacity at constant volume battery.</li><li><u>(C) Inventive solutions with reduced data transmission scheme:</u> Battery capacity: ~ 2.3 Ah at an operating voltage of 3V Typical operating time of an ICD: 6 years<dl id="dl0006" compact="compact"><dt>Data transmission scheme for remote monitoring:</dt><dd>1.5 dialins / week 5 event messages / year</dd></dl></li></ul>

p00331.5 dialins / week means it can contain max. 2 dialins week instead is the first successful, then the trial 2. not started. In the calculation it is assumed that the first dialing attempt is associated with a 50% success rate. Electricity demand with "field strength-dependent GSM dial"<dl id="dl0007" compact="compact"><dt>Dial Duration:</dt><dd>to 3 sec</dd><dt>Power consumption at an operating voltage of 3V:</dt><dd>to 0.25 A</dd></dl>Charge for remote monitoring = 83 dialins * 6 years * 3sec * 0.25A = 0.1 Ah

p0034With the inventive solution and a customized data transfer protocol, the application of a GSM modem in an ICD is possible without significant restriction of the operating time (&lt;5%) of the ICD.

p0035<figref idrefs="f0005">figure 5</figref> shows the block diagram of an alternative implementation. According to this variant, the cellular modem 500 with antenna 530, the SIM module 505 and the field strength detector in addition to matching network 510, 520 powered by a separate rechargeable battery 540th The charging of battery 540 is done for., Via a mounted outside the metallic implant case charging coil 550th

p0036The medically critical functions of the electronic implant, ie diagnostics and therapy control unit 580 and the message scheduler 570 and controller 560 are powered by a primary cell as a current or voltage source, so that the regularly required recharging of the battery is not a safety issue of the medical device, but only ensures the data transmission.

p0037<figref idrefs="f0006">figure 6</figref> shows in the description of <figref idrefs="f0003">figure 3</figref> mentioned access success statistics in a histogram 600 of transfer success rates for a certain time of day.

p0038In the individual histogram classes is held, whether a data transmission based on respective measured before connecting field strength class could be completed successfully.

p0039For the individual urgency classes of messages are different limits (610 ... 630) (minimum transmission success rate) set for the requested transfer success rate. A connection will only take place when the detected in the histogram transmission success rate exceeds the programmed for the particular urgency of the message threshold (minimum transmission success rate). Thus a transmission attempt is started when an emergency message is already at a small success rate (630), during a routine message, however, only at a very good success rate above the labeled with 610 transmission minimum success rate.

p0040Optional can be additionally increased in the emergency messages in combination with poor transmission success rate (630) the transmission power.

p0041The inventive solution is not limited to the use of GSM as the transmission standard, as can other transmission methods, such as by the cellular standards UMTS, HSDPA, HSUPA and LTE, as well as Bluetooth, WLAN or similar equally be used instead of GSM.