MRI Safety
MRI can put pacemaker patients at risk. We believe patient MRI safety must be proven by rigorous scientific testing and regulatory review.
MRI Safety Overview
Detail - Potential Hazards and Risks
Hazards and Risks of MRI With Current Pacing Systems1-4
Lead Heating
The conductive pacing lead acts as an antenna, picking up radiofrequency energy. A portion of this energy is dissipated as heat in the cardiac tissue near the tip electrode.
Impact: Thermal cardiac tissue damage may affect pacing therapy.
Unintended Cardiac Stimulation
The gradient and radiofrequency fields will induce voltages in pacemaker leads that will be applied to the pacing lead electrodes. If these voltage pulses are large enough, they may directly stimulate the heart.
Impact: Cardiac stimulation may lead to a single or intermittent stimulation, or sustained tachycardia.
Device Interactions
The gradient, radiofrequency, and static fields may adversely affect the electrical operation of the pacemaker system if its operation is not protected from the effects of those fields.
Impact: Pacemaker malfunction or failure may affect pacing therapy.
Case Heating
Electrical currents may be induced on the conductive surface of the pacemaker case.
Impact: Thermal tissue damage near the case may lead to patient discomfort.
Force and Torque
The static magnetic field will act on any ferromagnetic material in a pacemaker or lead, producing a translation or rotation of the device or lead.
Impact: Pacemaker or lead movement may lead to patient discomfort or may affect therapy.
Vibration
Gradient magnetic field induces electrical currents on the conductive surfaces of pacemaker components. Interaction of these currents with the static magnetic field causes the components to vibrate.
Impact: Pacemaker malfunction may affect pacing therapy.
MRI and Pacemakers: Potential Hazards and Risks (3:18, 3.9 MB)
Animation describing the increasing use of MRI as a diagnostic tool and the potential hazards and risks of MRI magnetic fields on patients with pacemakers.
Revo MRI Pacing System
The first pacing system FDA-approved for MRI use was specifically designed and engineered to address the hazards related to pacing during MRI.
Extensive testing and evaluation was conducted to assess the safety of the Revo MRI SureScan pacing system based on:
- Computer modeling
- Bench (in vitro) testing
- Animal (in vivo) studies
- Clinical trial
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 Systems 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.
References
- Kalin R, Stanton MS. Current clinical issues for MRI scanning of pacemaker and defibrillator patients. PACE. April 2005;28(4):326-328.
- Data on file. Medtronic, Inc. FDA MRI Panel Package.
- Bassen HI, Mendoza GG. In-vitro mapping of E-fields induced near pacemaker leads by simulated MR gradient fields. Biomed Eng Online. December 2009;8(1):39. (Abstract)
- Roguin A, Zviman MM, Meininger GR, et al. Modern pacemaker and implantable cardioverter defibrillator systems can be magnet resonance imaging safe. Circulation. August 3, 2004;110(5):475-482.
