MRI Safety for Implantable Cardiac Devices
 

Indications, Safety, and Warnings

MR Conditional Risk Information

  • A complete SureScan pacing system including a Revo MRI SureScan IPG and two CapSureFix MRI SureScan leads is required for use in the MRI environment
  • Any other pacing system combination may result in a hazard to the patient during an MRI scan
  • When programmed to On, the MRI SureScan feature allows the patient to be safely scanned while the device continues to provide appropriate pacing
  • Refer to the Revo MRI Pacing System Conditions for Use located in the device manuals prior to scanning a patient. Consult Medtronic’s website at www.medtronic.com or call Medtronic at 1 (800) 328-2518.


Revo MRI™ Pacing System – Conditions for Use

A complete SureScan™ pacing system including a Revo MRI SureScan IPG and two SureScan leads is required for use in the MRI environment.
Any other combination may result in a hazard to the patient during an MRI scan. The SureScan feature must be programmed to On prior to scanning a patient according to the specified conditions for use.

Cardiology requirements:

  • Patients and their implanted systems must be screened to meet the following requirements:
    • No previously implanted (active or abandoned) medical devices, leads, lead extenders, or lead adaptors
    • No broken leads or leads with intermittent electrical contact, as confirmed by lead impedance history
    • A SureScan pacing system that has been implanted for a minimum of 6 weeks
    • A SureScan pacing system implanted in the left or right pectoral region
    • Pacing capture thresholds of ≤ 2.0 volts (V) at a pulse width of 0.4 milliseconds (ms)
    • A lead impedance value of ≥ 200 ohms (Ω) and ≤ 1,500 Ω
    • No diaphragmatic stimulation at a pacing output of 5.0 V, and at a pulse width of 1.0 ms in patients whose device will be programmed to an asynchronous pacing mode when the MRI SureScan is on


Radiology requirements:

  • Horizontal, cylindrical bore magnet, clinical MRI systems with a static magnetic field of 1.5 Tesla (T) must be used
  • Gradient systems with maximum gradient slew rate performance per axis of ≤ 200 Teslas per meter per second (T/m/s) must be used
  • The scanner must be operated in Normal Operating mode:
    • The whole-body–averaged specific absorption rate (SAR) must be ≤ 2.0 watts per kilogram (W/kg)
    • The head SAR must be < 3.2 W/kg
  • The patient must be positioned within the bore such that the isocenter (center of the MRI bore) is superior to the C1 vertebra or inferior to the T12 vertebra
  • Proper patient monitoring must be provided during the MRI scan. The methods include visual and verbal contact with the patient, electrocardiography, and pulse oximetry (plethysmography).


Training requirements:

  • A health professional who has completed cardiology SureScan training must be present during the programming of the SureScan feature
  • A health professional who has completed radiology SureScan training must be present during the MRI scan


Brief Statement
The Revo MRI SureScan pacing system is MR Conditional and as such is designed to allow patients to undergo MRI under the specified conditions for use.

Indications
The Revo MRI™ SureScan™ Model RVDR01 IPG is indicated for use as a system consisting of Medtronic Revo MRI SureScan IPG implanted with two CapSure Fix MRI™ SureScan™ 5086MRI leads. A complete system is required for use in the MRI environment.

The Revo MRI™ SureScan™ Model RVDR01 IPG is indicated for the following:

  • Rate adaptive pacing in patients who may benefit from increased pacing rates concurrent with increases in activity
  • Accepted patient conditions warranting chronic cardiac pacing include:
    • Symptomatic paroxysmal or permanent second- or third-degree AV block
    • Symptomatic bilateral bundle branch block
    • Symptomatic paroxysmal or transient sinus node dysfunctions with or without associated AV conduction disorders
    • Bradycardia-tachycardia syndrome to prevent symptomatic bradycardia or some forms of symptomatic tachyarrhythmias


The device is also indicated for dual chamber and atrial tracking modes in patients who may benefit from maintenance of AV synchrony. Dual chamber modes are specifically indicated for treatment of conduction disorders that require restoration of both rate and AV synchrony, which include:

  • Various degrees of AV block to maintain the atrial contribution to cardiac output
  • VVI intolerance (for example, pacemaker syndrome) in the presence of persistent sinus rhythm


Antitachycardia pacing (ATP) is indicated for termination of atrial tachyarrhythmias in bradycardia patients with one or more of the above pacing indications.

Atrial rhythm management features such as Atrial Rate Stabilization (ARS), Atrial Preference Pacing (APP), and Post Mode Switch Overdrive Pacing (PMOP) are indicated for the suppression of atrial tachyarrhythmias in bradycardia patients with atrial septal lead placement and one or more of the above pacing indications.

The device has been designed for the MRI environment when used with the specified MR Conditions of Use.

Contraindications
The device is contraindicated for:

  • Implantation with unipolar pacing leads
  • Concomitant implantation with another bradycardia device
  • Concomitant implantation with an implantable cardioverter defibrillator


There are no known contraindications for the use of pacing as a therapeutic modality to control heart rate. The patient’s age and medical condition, however, may dictate the particular pacing system, mode of operation, and implantation procedure used by the physician.

  • Rate responsive modes may be contraindicated in those patients who cannot tolerate pacing rates above the programmed Lower Rate
  • Dual chamber sequential pacing is contraindicated in patients with chronic or persistent supraventricular tachycardias, including atrial fibrillation or flutter
  • Single chamber atrial pacing is contraindicated in patients with an AV conduction disturbance
  • ATP therapy is contraindicated in patients with an accessory antegrade pathway.


Warnings and Precautions
Changes in patient’s disease and/or medications may alter the efficacy of the device’s programmed parameters. Patients should avoid sources of magnetic and electromagnetic radiation to avoid possible underdetection, inappropriate sensing and/or therapy delivery, tissue damage, induction of an arrhythmia device electrical reset or device damange. Do not place transthoracic defibrillation paddles directly over the device. Use of the device should not change the application of established anticoagulation protocols.

Do not scan the following patients:

  • Patients who do not have a complete SureScan pacing system, consisting of a SureScan device and two SureScan leads;
  • Patients who have previously implanted devices, or broken or intermittent leads;
  • Patients who have a lead impedance value of < 200 Ω or > 1500 Ω;
  • Patients with a SureScan pacing system implanted in sites other than the left and right pectoral region.
  • Patients positioned such that the isocenter (center of MRI bore) is inferior to C1 vertebra and superior to the T12 vertebra


See the device manuals before performing an MRI Scan for detailed information regarding the implant procedure, indications, MRI conditions of use, contraindications, warnings, precautions, and potential complications/adverse events. For further information, call Medtronic at 1-800-328-2518 and/or consult Medtronic’s website at www.medtronic.com.

Caution: Federal law (USA) restricts this device to sale by or on the order of a physician.

Last updated: 26 Feb 2013