WO2005035048A2 - Commande de l'extinction lors d'une imagerie a resonance magnetique - Google Patents

Commande de l'extinction lors d'une imagerie a resonance magnetique Download PDF

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Publication number
WO2005035048A2
WO2005035048A2 PCT/US2004/031578 US2004031578W WO2005035048A2 WO 2005035048 A2 WO2005035048 A2 WO 2005035048A2 US 2004031578 W US2004031578 W US 2004031578W WO 2005035048 A2 WO2005035048 A2 WO 2005035048A2
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WO
WIPO (PCT)
Prior art keywords
mri
imd
signal
electromagnetic radiation
components
Prior art date
Application number
PCT/US2004/031578
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English (en)
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WO2005035048A3 (fr
Inventor
Volkert A. Zeijlemaker
Original Assignee
Medtronic, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Medtronic, Inc. filed Critical Medtronic, Inc.
Priority to AU2004279367A priority Critical patent/AU2004279367A1/en
Priority to EP04809802A priority patent/EP1680183A2/fr
Priority to CA002540206A priority patent/CA2540206A1/fr
Publication of WO2005035048A2 publication Critical patent/WO2005035048A2/fr
Publication of WO2005035048A3 publication Critical patent/WO2005035048A3/fr
Priority to IL174132A priority patent/IL174132A0/en

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/18—Applying electric currents by contact electrodes
    • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/362—Heart stimulators
    • A61N1/37—Monitoring; Protecting
    • A61N1/3702—Physiological parameters
    • A61N1/3704—Circuits specially adapted therefor, e.g. for sensitivity control
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/18—Applying electric currents by contact electrodes
    • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/362—Heart stimulators
    • A61N1/37—Monitoring; Protecting
    • A61N1/3718—Monitoring of or protection against external electromagnetic fields or currents

Definitions

  • the invention relates to magnetic resonance imaging (MRI) techniques.
  • Magnetic resonance imaging (MRI) techniques make use of electromagnetic fields to create images of a patient.
  • MRI techniques permit the generation of high-quality two- or three-dimensional images of a patient's body, which can then be examined by a physician for diagnosis purposes.
  • MRI techniques permit the generation of internal images of a patient's flesh, blood, bones, cartilage, blood vessels, organs, and the like. The generated images can then be examined by physicians in order to diagnose disease, disorders or injuries and facilitate patient care.
  • MRI devices typically subject a patient to a very strong static magnetic field and a pulsed gradient magnetic field, and then apply pulses or bursts of electromagnetic radiation (typically radio frequency (RF) radiation bursts) to an area of the patient to be imaged.
  • RF radio frequency
  • the strong magnetic field generally orients the protons of the patient's tissue in particular directions.
  • the RF radiation bursts cause some of the patient's protons to resonate, or spin, at a particular frequency depending on the local magnetic field during application of the radiation burst.
  • the resonance frequency in MRI is referred to as the Larmour frequency which has a linear relationship with the local magnetic field.
  • the resonating protons reorient themselves in accordance with the strong magnetic field of the MRI device, giving off energy in the process.
  • the MRI device can detect the energy given off by the reorienting protons in order to create a high quality image of the patient's tissue.
  • IMDs implantable medical devices
  • a pacemaker typically includes one or more pacing and sensing leads for delivery of pacing pulses to a patient's heart.
  • Another example of an IMD is a combination pacemaker-cardioverter-defibrillator.
  • implantable brain stimulators include implantable gastric system stimulators, implantable nerve stimulators or muscle stimulators, implantable lower colon stimulators, implantable drug or beneficial agent dispensers or pumps, implantable cardiac signal loops XL- ox other types of recorders or monitors, implantable gene therapy delivery devices, implantable incontinence prevention or monitoring devices, implantable insulin pumps or monitoring devices, and so on.
  • implantable cardiac signal loops XL- ox other types of recorders or monitors implantable gene therapy delivery devices, implantable incontinence prevention or monitoring devices, implantable insulin pumps or monitoring devices, and so on.
  • the strong static magnetic fields associated with MRI techniques may interact with the components of the IMD, possibly causing movement of the IMD within the patient because of magnetic attraction or repulsion. The interaction of the strong magnetic field with the IMD may cause trauma to the patient.
  • reductions in the mass of IMDs, as well as use of non-magnetic material or other selected material in IMD construction may reduce or eliminate the interaction of such magnetic fields with the IMD.
  • the invention is directed to techniques for coordinating the operation of an IMD with MRI techniques.
  • MRI techniques By coordinating the performance of MRI techniques with defined operation of the IMD, the use of MRI techniques on a patient that has an IMD can be facilitated.
  • the timing of electromagnetic radiation bursts emitted by an MRI device can be communicated to the IMD.
  • the IMD can respond to the timing information by activating a "blanking period" during the time when the electromagnetic radiation bursts occur.
  • a blanking period refers to a period during which one or more sensing components of the IMD, such as sensing amplifiers, are disabled within the IMD sensing circuitry.
  • Blanking periods coordinated with MRI electromagnetic radiation bursts and gradients can avoid undesirable action by the IMD in response to the electromagnetic radiation bursts. Even after solving problems associated with interaction between a strong magnetic field of an MRI and an IMD in a patient, other problems may still limit the ability to use MRI in patients that have an IMD.
  • the RF radiation bursts associated with MRI techniques may interfere with IMD operation, possibly causing miscalculations by i the IMD, or worse yet, undesirable therapy to be delivered to the patient by the IMD.
  • IMD operation may be more compatible with MRI.
  • the invention provides a method of coordinating MRI comprising blanking one or more components of an IMD during delivery of electromagnetic radiation bursts to a patient.
  • the invention provides an implantable medical device comprising a receiver to receive a signal, and a control unit that in response to the signal, blanks one or more components of an IMD during application of MRI electromagnetic radiation bursts.
  • the invention provides an implantable medical device (IMD) that disables one or more components during delivery of MRI electromagnetic radiation bursts to a patient.
  • IMD implantable medical device
  • the invention provides a system comprising an MRI device including a transmitter to transmit a signal relating to application of an MRI electromagnetic radiation burst, and an IMD including a receiver to receive the signal, and a control unit to blank one or more components of the IMD during application of the MRI electromagnetic radiation burst.
  • the invention provides a system comprising a programmer to define a timing for application of a magnetic resonance imaging (MRI) electromagnetic radiation burst, an MRI device to receive a first signal from the programmer and apply the electromagnetic radiation burst according to the timing, and an IMD to receive a second signal from the programmer and blank one or more components of the IMD during application of the MRI electromagnetic radiation burst.
  • MRI magnetic resonance imaging
  • the invention provides an apparatus comprising means for receiving an indication of a timing of an application of an MRI electromagnetic radiation burst, and means for blanking one or more components of an IMD during application of the MRI electromagnetic radiation burst.
  • the invention provides an MRI device that sends a signal to an IMD to cause the IMD to blank on or more components during application of one or more electromagnetic radiation bursts by the MRI device.
  • the different embodiments may be capable of providing a number of advantages. For example, by coordinating the performance of MRI techniques with operation of the
  • the use of MRI techniques on patients that have an IMD can be facilitated.
  • blanking periods coordinated with MRI electromagnetic radiation bursts can avoid undesirable action by the IMD in response to the electromagnetic radiation bursts.
  • patient care can be improved.
  • FIG. 1 is a conceptual diagram illustrating a magnetic resonance imaging (MRI) device communicating with an implantable medical device (IMD).
  • FIG. 2 is a functional block diagram of an MRI device communicating with an IMD.
  • FIG. 3 is a flow diagram illustrating a technique for coordinating MRI techniques with the operation of an IMD according to an embodiment of the invention.
  • FIG. 4 is another conceptual diagram illustrating an external programmer coordinating an MRI device and an IMD in accordance with an embodiment of the invention.
  • the invention is directed to techniques for coordinating the operation of an implantable medical device (IMD) with magnetic resonance imaging (MRI) techniques.
  • IMD implantable medical device
  • MRI magnetic resonance imaging
  • timing of electromagnetic radiation bursts in MRI techniques can be communicated to the IMD prior to execution of the electromagnetic radiation bursts.
  • the IMD can respond to the timing information by activating "blanking periods" during the time when the electromagnetic radiation bursts occur.
  • a blanking period refers to a period during which one or more sensing components of the IMD, such as sensing amplifiers are disabled from the IMD sensing circuitry. Synchronizing IMD blanking periods with times when MRI electromagnetic radiation bursts occur can avoid undesirable action by the IMD in response to the electromagnetic radiation bursts. In particular, sensing and responsive stimulation to the bursts may be avoided.
  • FIG. 1 is a conceptual diagram of a patient 1 inside an MRI device 20.
  • Patient 1 has an IMD 10.
  • IMD 10 is illustrated as a cardiac pacemaker that provides therapeutic electrical stimulation to heart 5.
  • IMD 10 may generally comprise any of a wide variety of medical devices that can be implanted in the body of a human or other life form.
  • IMD 10 may alternatively take the form of an implantable cardioverter, an implantable defibrillator, or an implantable cardiac pacemaker-cardioverter-defibrillator.
  • IMD 10 may deliver pacing, cardioversion or defibrillation pulses to a patient via electrodes disposed on distal ends of one or more leads 2.
  • one or more leads 2 may position one or more electrodes with respect to various cardiac locations so that IMD 10 can deliver pulses to the appropriate locations.
  • the techniques described herein may useful to coordinate MRI techniques with other IMDs, such as patient monitoring devices, or devices that integrate monitoring and stimulation features.
  • the invention may be used with a neurological device such as a deep-brain stimulation device or a spinal cord stimulation device.
  • MRI device 20 may assume a wide variety of shapes, sizes or configurations. In the illustrated example of FIG. 1, MRI device 20 defines a relatively large tubular cavity
  • MRI device 20 may define a much smaller cavity, e.g., for insertion of a patients arm, leg, head, or the like.
  • MRI device 20 includes a set of MRI components inside housing 25, such as circuitry, magnets, inductors and the like, that support operation of MRI device 20.
  • MRI device 20 makes use of electromagnetic fields to create images of patient 1.
  • MRI device 20 may subject a patient to a very static strong magnetic fields and gradient fields via one or more permanent magnets or electro magnets located about cavity 22 or within housing 25.
  • MRI device 20 then applies radiation bursts, e.g., pulses of electromagnetic radiation (typically radio frequency (RF) radiation) to an area of the patient 1 to be imaged.
  • housing 25 may house various components that generate and apply RF radiation bursts at desired frequencies associated with the particular tissue of patient 1 to be imaged.
  • the strong magnetic field generally orients the protons of patient 1 in particular directions.
  • the RF radiation bursts cause some of the patient's protons to resonate, or spin, at a particular frequency during the application of the RF radiation bursts.
  • the resonance frequency applied by MRI device 20 is referred to as the Larmour frequency which has a linear relationship with the local magnetic field.
  • MRI device 20 can detect the energy given off by the local reorienting protons at the different positions in patient 1 to create a high quality image of the tissue or matter of patient 1.
  • MRI device 20 and IMD 10 coordinate operation so as to avoid undesirable action by IMD 10 during MRI operation.
  • MRI device 20 and IMD 10 coordinate to ensure that certain functions of IMD 10, such as sensing functions, are disabled or blanked, during the application of the RF radiation bursts.
  • one or more wireless signals 28 can be communicated between IMD
  • Blanking refers to a technique in which the functionality of one or more components of an IMD 10 are temporarily disabled.
  • a blanking period refers to the period of time during which such blanking occurs. Conventionally, blanking is used in cardiac pacemakers for a brief blanking period following application of a stimulus.
  • blanking periods can be coordinated with the application of MRI electromagnetic radiation bursts and the application of gradient fields in order to ensure that electrical events associated with the radiation bursts and gradients are not sensed. If sensed, the radiation bursts or gradients might be misinte ⁇ reted by IMD 10, possibly causing IMD 10 to respond in a manner that would be undesirable. In addition, sensing during the radiation bursts may cause saturation one or more sensors, which can take IMD 10 many milliseconds or even seconds to recover.
  • FIG. 2 is a block diagram illustrating a system 30 that includes an MRI device 20 and an IMD 10.
  • MRI device 20 communicates to IMD 10 via wireless signals 28.
  • any of a wide variety of telemetry techniques may be used to facilitate transfer of information from MRI device 20 to IMD 10.
  • the transferred information provides IMD 10 with an indication of the timing, e.g., the start time and duration, of one or more electromagnetic radiation bursts to be applied by MRI device 20.
  • IMD 10 can use this information to define one, or more blanking periods as described herein.
  • the MRI device 20 may simply communicate one or more control signals to cause IMD 10 to activate a blanking period, e.g., just before application of an electromagnetic radiation burst.
  • the communication of timing information may provide absolute timing control, whereas the sending of control signals may provide relative timing control.
  • IMD 10 includes a receiver 32 and an antenna 34 to facilitate reception of wireless signals 28 from MRI device 20.
  • IMD 10 also includes circuitry 36 for sensing and/or stimulating a patient for therapeutic purposes.
  • sensing/stimulation circuitry 36 may include electrodes disposed on medical leads and implanted at locations in a patient where sensing and stimulation occurs.
  • Sensing/stimulation circuitry 36 typically includes one or more amplifiers to enhance the cardiac signals for effective sensing or to generate the electrical potentials needed for effective sensing and/or stimulation.
  • IMD control unit 38 coordinates circuitry 36 so that sensing and stimulation occurs at proper times.
  • IMD control unit 38 may define various sensing and stimulation algorithms that define the therapy to be provided.
  • IMD control unit 38 may execute algorithms that inte ⁇ ret sensed information from circuitry 36 and determine whether an arrhythmia has occurred in the heart. If IMD control unit 38 identifies an arrhythmia, it may store this information, and possibly respond by causing circuitry 36 to provide stimulation therapy specifically for the identified arrhythmia. IMD control unit 38 may execute a number of algorithms to identify and respond to a wide variety of potential arrhythmias in the patient's heart.
  • MRI device 20 includes a transmitter 42 and an antenna 44 to facilitate transmission of wireless signals 28 to IMD 10. MRI device 20 makes use of electromagnetic fields to create images of a patient.
  • MRI techniques are particularly useful in creating images of blood flow, images to facilitate identification of cancer, or other images that can not be easily generated via conventional imaging techniques such as X-ray techniques, or the like
  • MRI device 20 includes one or more magnetic field generators 45 and one or more electromagnetic radiation sources 46.
  • magnetic field generator 45 generate a relatively large magnetic field, e.g., in the range of 0.2 to 20 Tesla.
  • Magnetic field generator 45 may include a permanent magnet, an electromagnet, or the like, and may also include gradient field generators to impose gradient fields during the MRI.
  • magnetic field generator 45 may include a permanent magnet, an electromagnet, or the like, and may also include gradient field generators to impose gradient fields during the MRI.
  • MRI device 20 includes one or more electromagnetic radiation sources 46, such as radio frequency (RF) radiation sources.
  • RF radio frequency
  • Electromagnetic radiation source 46 of MRI device 20 then applies pulses or bursts of electromagnetic radiation (typically RF radiation) to an area of the patient to be imaged.
  • the strong magnetic field of magnetic field generators 45 generally orients the protons of patient in particular directions, but the RF radiation bursts of electromagnetic radiation source 46 causes some of the patient's protons to resonate.
  • the RF radiation burst is terminated, the resonating protons reorient in accordance with the local strong magnetic field of the magnetic field generators 45, giving off energy in the process.
  • Imaging unit 48 of MRI device 20 can receive and detect the energy given off by the reorienting protons. Imaging unit 48 uses the detected energy given off by the reorienting protons to create one or more images of the tissue or matter of the patient. In this manner, MRI device 20 is used to create medical images.
  • MRI control unit 49 coordinates the application of RF radiation bursts by electromagnetic radiation source 46, and the imaging by imaging unit 48. In particular, MRI control unit 49 may define the timing of the RF radiation bursts by electromagnetic radiation source 46, including the start time and duration of any given burst. MRI control unit 49 may perform one or more algorithms to coordinate and define the MRI techniques of MRI device 20.
  • MRI control unit 49 may blank one or more electrical components of MRI device 20 during application of the RF radiation bursts, e.g., to avoid electrical interference or malfunction of the components.
  • MRI device 20 communicates information (or a control signal) to IMD 10 via transmitter 42 and antenna 44. More specifically, information in MRI control unit 49 defining the timing of RF radiation bursts to be applied by electromagnetic radiation source 46 can be communicated to IMD 10 to via transmitter 42 and antenna 44. This timing information may include a start time of a burst, a duration of a burst, information regarding sequence of bursts, or the like, that defines when one or more of the RF radiation bursts are to occur.
  • the information may include indication of gradient field application by MRI device 20.
  • MRI control unit 49 may generate this information specifically for sending to IMD 10, or may have already generated the information for pu ⁇ oses of blanking one or more components of MRI device 20 during application of the RF radiation bursts. In the latter case, the same information used by MRI control unit 49 to cause blanking of one or more components of MRI device 20 can be communicated to IMD 10 to facilitate blanking of one or more components of IMD 10.
  • IMD 10 uses the timing information to blank sensing or stimulation amplifiers within circuitry 36 during the application of RF radiation bursts by
  • MRI device 20 may use the generated timing information to send one or more commands or control signals to IMD 10 to cause activation of blanking.
  • blanking is activated during the electromagnetic radiation bursts.
  • an internal clock of MRI device 20 and IMD 10 may be synchronized to improve timing of the blanking periods. For example, clock synchronization may be communicated between the devices to achieve such synchronization.
  • MRI control unit 49 may send the information to an IMD programmer, which can coordinate blanking in IMD
  • FIG. 3 is a flow diagram illustrating a technique for coordinating MRI techniques with the operation of an IMD according to an embodiment of the invention.
  • IMD 10 receives a signal indicating timing of a burst interval of MRI (51).
  • the signal may specify timing of applications of bursts and gradients.
  • IMD 10 may receive the signal from MRI device 20, or alternatively from another device such as an external programmer that coordinates MRI techniques with IMD operation.
  • the timing of the burst interval may be defined, e.g., by a start time and a duration, although other variables may also be included in the timing such as a timing sequence that defines timing for a number of bursts.
  • IMD 10 Upon receiving the signal that indicates the timing of the burst interval, IMD 10 subsequently initiates a blanking period just prior to the burst interval (52). Again, in alternative embodiments MRI device 20 may send a control signal that initiates the blanking. In any case, the blanking period may be defined to substantially correspond to the burst interval, or may be made slightly larger than the burst interval in order to ensure that the blanking period does not begin late or terminate early. Once the burst interval is done (yes branch of 53), IMD 10 terminates the blanking period (54). Thus, the sensing components that were disabled during the blanking interval, are reactivated following the blanking period.
  • IMD 10 is fully capable of sensing and/or stimulating the patient for therapeutic pu ⁇ oses. This is very useful because if the RF radiation burst caused negative effects to the patient, or if an episode such as an arrhythmia in the heart occurs when the patient is in the MRI device 20, IMD 10 may be capable of sensing and responding to the episode. Accordingly, blanking IMD 10 only at selected times during MRI techniques may provide a number of advantages over a complete disabling of IMD 10, most notably that patient conditions can be monitored and therapy may be provided during the MRI, if necessary. Moreover, operation of IMD 10 itself may be used to improve the MRI process by providing improved sensing and/or stimulation specifically for the MRI process.
  • an IMD may'sense conditions or provide stimulation specifically for the pu ⁇ ose of enhancing MRI.
  • a cardiac pacemaker can be used to sense or stimulate the heart so as to more properly ensure that the heart is in a desired interval of sinus rhythm when MRI radiation bursts are applied for imaging.
  • Such techniques of sensing or stimulating the heart to coordinate MRI radiation bursts at specific intervals of sinus rhythm may be used in conjunction with the techniques that define blanking periods during the radiation bursts.
  • the IMD is disabled during the MRI process, such advantages associated with IMD operation in the MRI device could not be achieved.
  • the process may repeat if another MRI radiation burst is to be performed (yes branch of 55).
  • the timing information in a received signal may define a number of MRI radiation bursts, e.g., a sequence of bursts.
  • a number of blanking periods may be executed by IMD 10 in response to one received signal that communicates the sequence to IMD 10.
  • FIG. 4 is another conceptual diagram illustrating an alternative configuration in which an external programmer 60 coordinates MRI device 20 and IMD 10.
  • programmer 60 defines the timing of MRI radiation bursts and communicates signals to IMD 10 and MRI device 20.
  • First signal 71 may be a wireless signal, whereas the second signal may be transmitted over wire 72.
  • a wireless interface may be used between programmer 60 and MRI device 20.
  • the first and second signals sent from programmer 60 respectively to IMD 10 and MRI device 20 may be substantially similar, may be specifically defined for communication with the different receiving device 10 or 20.
  • MRI device 20 applies MRI electromagnetic radiation bursts according to timing communicated from programmer 60, and IMD 10 enters blanking periods during such application of the radiation bursts by using the timing information communicated from programmer 60.
  • Application of gradient fields by MRI device 20 and blanking by IMD 10 may also be coordinated.
  • programmer 60 receive signals via wire 72 from MRI device 20 defining the timing of RF radiation bursts, and communicate signals 71 to IMD 10 so as to forward this information for use by IMD 10 in blanking. Also, programmer 60 may also use the received signals from MRI device 20 that define the timing in order to ensure that telemetry does not occur during the RF radiation bursts.
  • IMD 10 may measure or detect the electromagnetic radiation bursts, and activate blanking upon such detection. The disclosed embodiments are presented for pu ⁇ oses of illustration and not limitation, and the invention is limited only by the claims that follow.

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Abstract

L'invention concerne une structure et des méthodes pour coordonner le fonctionnement d'un dispositif médical implantable (IMD) et de techniques d'imagerie par résonance magnétique (IRM). Par exemple, l'IMD peut permettre d'activer une période d'extinction, pendant la période de rafales de rayonnements électromagnétiques. L'extinction d'un IMD, lors de rafales de rayonnements électromagnétiques d'IRM peut permettre d'éviter une action non voulue ou une détection incorrecte de l'IMD, lorsque celui-ci subit l'influence des rafales de rayonnements magnétiques.
PCT/US2004/031578 2003-09-29 2004-09-28 Commande de l'extinction lors d'une imagerie a resonance magnetique WO2005035048A2 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
AU2004279367A AU2004279367A1 (en) 2003-09-29 2004-09-28 Controlling blanking during magnetic resonance imaging
EP04809802A EP1680183A2 (fr) 2003-09-29 2004-09-28 Commande de l'extinction lors d'une imagerie a resonance magnetique
CA002540206A CA2540206A1 (fr) 2003-09-29 2004-09-28 Commande de l'extinction lors d'une imagerie a resonance magnetique
IL174132A IL174132A0 (en) 2003-09-29 2006-03-06 Controlling blanking during magnetic resonance imaging

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US63777803A 2003-09-29 2003-09-29
US10/637,778 2003-09-29

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WO2005035048A2 true WO2005035048A2 (fr) 2005-04-21
WO2005035048A3 WO2005035048A3 (fr) 2005-07-21

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AU (1) AU2004279367A1 (fr)
CA (1) CA2540206A1 (fr)
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WO2007094976A1 (fr) * 2006-02-16 2007-08-23 Cardiac Pacemakers, Inc. Détecteur d'irm pour dispositif médical implantable
WO2007117835A1 (fr) * 2006-03-30 2007-10-18 Medtronic, Inc. dispositif médical pour capter et détecter pendant une IRM
DE102006016043A1 (de) * 2006-04-05 2007-10-18 Siemens Ag Sicherheitssystem sowie Verfahren zur Feststellung einer möglichen Gefährdung einer Person durch ein Gerät
WO2007124273A1 (fr) * 2006-04-24 2007-11-01 Medtronic, Inc. Détection d'appareil médical implanté
US8165691B2 (en) 2009-10-19 2012-04-24 Medtronic, Inc. Implantable medical device with selectively configurable exposure operating mode programming options
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US8391992B2 (en) 2009-12-30 2013-03-05 Cardiac Pacemakers, Inc. Implantable medical device switching power supply including multiple modes
US8433408B2 (en) 2011-04-27 2013-04-30 Medtronic, Inc. Pacing in the presence of electromagnetic interference
US8805496B2 (en) 2009-01-30 2014-08-12 Medtronic, Inc. Automatic disablement of an exposure mode of an implantable medical device
USRE48197E1 (en) 2014-07-25 2020-09-08 Medtronic, Inc. Atrial contraction detection by a ventricular leadless pacing device for atrio-synchronous ventricular pacing
US11207527B2 (en) 2016-07-06 2021-12-28 Cardiac Pacemakers, Inc. Method and system for determining an atrial contraction timing fiducial in a leadless cardiac pacemaker system

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AU2004279367A1 (en) 2005-04-21
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CA2540206A1 (fr) 2005-04-21
IL174132A0 (en) 2006-08-01

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