the following description is of the best mode presently contemplated for carrying out at least one embodiment of the invention . this description is not to be taken in a limiting sense , but is made merely for the purpose of describing the general principles of the invention . the scope of the invention should be determined with reference to the claims . fig1 shows a heart therapy and / or heart monitoring device and system , including a three - chamber icd system as an example of an active implantable medical device , according to one or more embodiments of the invention . in at least one embodiment , the implantable medical device may include a generator 100 , or a heart stimulator 100 , for example as the heart therapy and / or heart monitoring device , connected to a number of implantable electrode lines 110 , 112 and 114 . one or more embodiments may include a right - ventricular ( rv ) electrode line 110 that provides right - ventricular sensing and delivers stimulation , which may include a right - ventricular ( rv ) tip electrode 121 and a right - ventricular ( rv ) ring electrode 122 at the distal end thereof . during operation , in at least one embodiment , right - ventricular stimulation pulses may be delivered as necessary to deliver biventricular crt stimulation via the rv tip electrode 121 . one or more embodiments may include shock electrodes or coils 123 , such as a distal shock coil 123 and / or a proximal shock coil ( not illustrated ), attached to the rv electrode line 110 , to deliver shock . in at least one embodiment , the generator housing of the generator 100 may be a counter electrode . in one or more embodiments , electrode line 112 may be a right - atrial electrode line 112 , which , at the distal end thereof , may include a bipolar sensing and stimulation pole with a right - atrial tip electrode 131 and a right - atrial ring electrode 132 . in one or more embodiments , the right - atrial electrode line 112 may sense the atrial rhythm and may stimulate the atrium . in at least one embodiment , the system may include a left - ventricular coronary sinus ( cs ) electrode line to deliver left - ventricular stimulation pulses that provide crt via one or more of four left - ventricular ( cs ) stimulation electrode poles 141 , 142 , 143 and 144 . one or more embodiments may include a wireless bidirectional telemetry unit , for example in the generator 100 , to communicate with one or more of external programming devices , control devices , and data transfer devices 160 . fig2 shows the main components of the heart stimulator 100 of fig1 , according to one or more embodiments of the invention . as shown in fig2 , at least one embodiment may include electrical terminals that correspond to the various electrodes 121 , 122 , 131 and 132 , as illustrated on the left - hand side of fig2 . in one or more embodiments , the shock electrodes 123 may be connected to a right - ventricular shock pulse generator 50 . in at least one embodiment , the shock pulse generator 50 may be connected to a stimulation control unit 54 , wherein the stimulation control unit 54 activates the shock pulse generator 50 as required in order to generate and deliver a defibrillation shock . in one or more embodiments , the terminal of the right - ventricular tip electrode 121 ( rv tip ) and the connection of the right - ventricular ring electrode 122 ( rv ring ) may each be connected both to a right - ventricular stimulation unit 56 and to a right - ventricular sensing unit 58 . in at least one embodiment , the right - ventricular stimulation unit 56 and the right - ventricular sensing unit 58 may each be connected to the stimulation control unit 54 . by way of one or more embodiments , the right - ventricular stimulation unit 56 may generate a right - ventricular stimulation pulse in response to an actuation signal of the stimulation control unit 54 , and may deliver the right - ventricular stimulation pulse via the right - ventricular ring electrode 122 ( rv ring ) and the right - ventricular tip electrode 121 ( rv tip ). in at least one embodiment , the housing of the generator 100 may form a neutral electrode , and the right - ventricular stimulation unit 56 may be connected to the terminal of the right - ventricular ring electrode 122 ( rv tip ) and the housing as another electrode to deliver a stimulation pulse . in one or more embodiments , a right - ventricular stimulation pulse may be distinguished from a defibrillation shock in the that the stimulation pulse may include a much lower pulse intensity , such that the stimulation pulse does not excite the entire heart tissue ( myocardium ) of a heart chamber all at once , compared to a defibrillation shock , but excites the heart muscle cells in the immediate vicinity of the right - ventricular tip electrode 121 ( rv tip ). in at least one embodiment , the excitation may spread by natural stimulus conduction over the entire right ventricle and may ensure a stimulated contraction of the right ventricle . in one or more embodiments , the right - ventricular sensing unit 58 may amplify and may filter , initially by an input amplifier , electric potentials applied to the terminal of the right - ventricular ring electrode 122 ( rv ring ) and the right - ventricular tip electrode 121 ( rv tip ). in at least one embodiment , the right - ventricular sensing unit 58 may evaluate the profile of the electric signals applied to the inputs of the sensing unit 58 , such that the right - ventricular sensing unit 58 may automatically detect a natural ( intrinsic ) event , for example an automatic contraction of the right ventricle . in one or more embodiments , such detection may be implemented for example such that the profile of the signal applied to the inputs of the right - ventricular sensing unit 58 is compared with a threshold value . in at least one embodiment , the greatest amplitude of the signal is the r - wave , which defines a natural contraction of the right ventricle , and which may be detected by threshold value comparison . in one or more embodiments , the right - ventricular sensing unit 58 may output a corresponding output signal to the stimulation control unit 54 , wherein the output signal indicates a natural contraction of the right ventricle . in at least one embodiment , the moment in time at which the threshold value is exceeded may include the moment of detection for the respective event . at least one embodiment may include one or more sensing units ( not illustrated in fig2 ) for the shock electrodes . in one or more embodiments , the one or more sensing units may detect signals between the shock electrodes , between the shock electrode 123 and the housing of the generator 100 , or between the other shock electrode ( the proximal shock electrode or coil ) and the housing of the generator 100 . in at least one embodiment , the terminal of the right - atrial tip electrode 131 ( ra tip ) and the terminal of the right - atrial ring electrode 132 ( ra ring ) may be both connected to a right - atrial stimulation unit 60 and to a right - atrial sensing unit 62 , which are each in turn connected to the stimulation control unit 54 . in one or more embodiments , the right - atrial stimulation unit 60 may generate stimulation pulses , of which the intensity is sufficient to excite the right - atrial myocardium . in at least one embodiment , the right - atrial stimulation pulses may include a pulse intensity that differs from the right - ventricular stimulation pulses . in one or more embodiments , the right - atrial sensing unit 62 may detect a p - wave from the course of the differential signal applied to the inputs of the sensing unit 62 , wherein the p - wave defines a natural ( intrinsic ) contraction of the right atrium . in at least one embodiment , when the right - atrial sensing unit 62 detects a corresponding p - wave , the right - atrial sensing unit 62 may generate an output signal and may forward the output signal to the stimulation control unit 54 , which defines a natural contraction of the right atrium . by way of one or more embodiments , the terminal of the left - ventricular tip electrode 141 ( lv tip ) and the terminals of the left - ventricular ring electrodes 142 , 143 and 144 may be connected in a similar manner to a left - ventricular stimulation unit 64 and a left - ventricular sensing unit 66 . in at least one embodiment , the left - ventricular stimulation unit 64 and the left - ventricular sensing unit 66 may be connected to the stimulation control unit 54 . in one or more embodiments , the left - ventricular stimulation unit 64 and the left - ventricular sensing unit 66 may function similarly to the stimulation units 56 and 60 and sensing units 58 and 62 as described above . according to at least one embodiment , the heart stimulator 100 may include an acceleration sensor 72 connected to the stimulation control unit 54 , wherein the acceleration sensor 72 may be integrated into the housing of the heart stimulator 100 . in one or more embodiments , the acceleration sensor 72 may detect a movement signal dependent on a physical activity of a patient and may output a corresponding first accelerometer output signal to the stimulation control unit 54 , indicating the physical activity of the patient . as such , in one or more embodiments , the stimulation control unit 54 may adapt the timing of the stimulation pulse to the need of the patient ( hemodynamic need ). in at least one embodiment , the accelerometer output signal may be used to determine rest phases , in which a dislocation thereof may be detected . in one or more embodiments , the generator 100 may include a memory unit 80 connected to the stimulation control unit 54 . in at least one embodiment , the memory unit 80 may store signals generated or evaluated by the stimulation control unit 54 . in one or more embodiments , the memory unit 80 may store control programs for the stimulation control unit 54 , wherein the control programs may be modified . in at least one embodiment , the stimulation control unit 54 may be connected to an mri sensor 200 . in one or more embodiments , the mri sensor 200 may include a field detection unit , as will be described further below regarding fig4 . in at least one embodiment , the mri sensor 200 may include one or more of a magnetic field sensor , a gradient field sensor , a high - frequency field sensor , a position sensor , a vibration sensor ( such as a lorentz vibration sensor ), and a voltage profile sensor . in one or more embodiments , the memory unit 80 may be connected to a telemetry unit 84 , wherein the telemetry unit 84 may one or more of wirelessly transfer data stored in the memory unit 80 to the external device 160 , transfer program commands from the external device 160 to the heart stimulator 100 , and store the transfer program commands in the memory unit 80 . in at least one embodiment , the implantable electronic device may allow an automatic mri detection and switchover into a safe state during an mri examination , wherein at least two patient - tailored mri program settings may be stored in the implantable electronic device and may be selected automatically in accordance with a patient status detected by the implant prior to the mri examination . fig3 illustrates a typical course of an mri examination of an icd patient without a device according to embodiments of the invention . as shown in fig3 , an icd patient 300 may include an aftercare consultation with a cardiologist 310 before the planned mri examination , wherein the icd is switched off . the mri examination may be carried out by a radiologist 320 after a temporal delay lasting from hours to a few days . after a further delay , the patient may again be treated by the cardiologist 330 and the icd may be switched back on . during the entire period starting with the mri examination by a radiologist 320 to the renewed switching - on of the icd by the cardiologist 330 , the patient is without the protection of the implanted defibrillator and may be without rhythm monitoring . the remaining residual risk , for example , which may be measured in proportion to the benefit of the mri examination , is generally accepted . by way of one or more embodiments , with the use of an mri sensor 200 , the illustrated sequence of fig3 may be changed such that the mri setting may only be effective directly during the mri examination and the subsequent aftercare by the cardiologist 330 for reprogramming may be spared . typically , the moment of the first aftercare consultation by the cardiologist 310 in order to determine the mri program cannot take place arbitrarily prior to the actual mri examination by the radiologist 320 , since the conditions of the patient may change , and therefore an adaptation of the mri program may be necessary . at least one embodiment of the invention provides an anti - bradycardia stimulation . in one or more embodiments , patients who do not require any stimulation may be examined in principle in the off mode in the mri scanner to avoid the risk of arrhythmia induction . in at least one embodiment , patients who require stimulation , however , may be stimulated in an asynchronous operating mode ( such as v00 , d00 ) in the mri scanner . in one or more embodiments , the respective pacemaker dependency may change over the course of time . fig4 shows a block diagram of an mri sensor 200 of the electronic implant 100 , according to one or more embodiments of the invention . in at least one embodiment , the mri sensor 200 may include at least one antenna 210 , connected to an antenna matching network / amplifier 220 . in one or more embodiments , the antenna matching network / amplifier 220 may be connected to a tunable low - current broadband frequency identification unit 230 , which may scan the field strengths of the defined ambient frequencies cyclically and may signal the field strengths to a control unit 240 . in at least one embodiment , the control unit 240 may compare all ambient frequencies received from the broadband frequency identification unit 230 having a field strength above a ( respective ) predefined limit field strength with previously stored field characteristics . for example , in at least one embodiment , previously stored field characteristics may include previously stored frequency ranges of the ambient frequencies , which may be present in the environment of the implantable electronic device outside the environment of the mri device . by way of one or more embodiments , when the control unit 240 does not identify any of the previously stored ambient frequencies , the control unit 240 may signal an mri environment . in at least one embodiment , the broadband frequency identification unit 230 may form a field detection unit together with the control unit 240 . in one or more embodiments , suitable frequencies may be selected from the frequency bands between 30 khz to 30 ghz . it will be apparent to those skilled in the art that numerous modifications and variations of the described examples and embodiments are possible in light of the above teaching . the disclosed examples and embodiments are presented for purposes of illustration only . other alternate embodiments may include some or all of the features disclosed herein . therefore , it is the intent to cover all such modifications and alternate embodiments as may come within the true scope of this invention .
embodiments include an implantable electronic device with at least one electromagnetic field detection unit and at least one antenna , wherein the at least one electromagnetic field detection unit is connected to the at least one antenna . the at least one electromagnetic field detection unit responds to electromagnetic fields that occur or are present in an environment surrounding a patient outside an environment of an mri device and electromagnetic fields that are shielded in the environment of the mri device . the at least one electromagnetic field detection unit indicates an absence of the electromagnetic fields that typically occur in the environment surrounding a patient outside an mri device and that are shielded in the environment of an mri device .