Healthcare Professionals

Micra

Transcatheter Pacing System

  • micra

MRI Safety

MRI can put pacemaker patients at risk. We believe patient MRI safety must be proven by rigorous scientific testing and regulatory review. Micra is FDA approved for 1.5T and 3T MRI scans under specific conditions for use.

MRI Safety Overview

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Hazards and Risks of MRI With Current Pacing Systems1-4

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.

 

 

References

1

Kalin R, Stanton MS. Current clinical issues for MRI scanning of pacemaker and defibrillator patients. PACE. April 2005;28(4):326-328.

2

Data on file. Medtronic, Inc. FDA MRI Panel Package.

3

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)

4

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.