Related Experiment Video
Updated: Jun 17, 2026
10:17
Real-Time Cardiac Mapping with a Noninvasive Imageless Electrocardiographic Imaging System
Published on: April 11, 2025
In-vitro mapping of E-fields induced near pacemaker leads by simulated MR gradient fields.
Howard I Bassen1, Gonzalo G Mendoza
1Division of Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, FDA, 10903 New Hampshire Avenue Silver Spring, MD 20993-0002, USA. howard.bassen@fda.hhs.gov
Biomedical Engineering Online
|December 17, 2009
Summary
Magnetic resonance imaging (MRI) gradient fields can induce electric fields (E) near pacemaker leads, potentially causing unintended cardiac stimulation. These induced E can exceed those from a pacemaker pulse generator (PG) under specific conditions.
Area of Science:
- Biomedical Engineering
- Medical Physics
- Cardiovascular Technology
Background:
- Magnetic resonance imaging (MRI) is generally contraindicated for patients with implanted cardiac pacemakers.
- Some clinicians permit MRI scans for specific patients, necessitating risk assessment.
- Unintended cardiac stimulation is a primary concern during MRI in pacemaker patients.
Purpose of the Study:
- To assess the risk of unintended cardiac stimulation in pacemaker patients during MRI.
- To measure electric fields (E) induced near pacemaker lead tips by simulated MRI gradient systems.
- To compare induced E with those generated by a pacemaker pulse generator (PG).
Main Methods:
- Magnetically induced E near lead tips were mapped with 0.1 mm resolution.
- Electric fields were measured using probes with two straight electrodes.
- Magnetic flux density (B) was generated using a Helmholtz coil in a saline tank.
- Induced E were compared to E measured from a PG in unipolar mode.
Main Results:
- Magnetically induced E, when scaled to 30 T/s, surpassed E produced by a PG.
- Induced E occurred only when magnetic flux density (B) coincided with or was near the pacemaker pulse.
- Spatial distribution and magnitude of induced E were determined near lead tips.
Conclusions:
- Gradient fields during MRI can create potentially hazardous situations for pacemaker patients.
- Unintended stimulation can occur through abandoned leads or compromised pulse generator connections.
- Pacemaker-dependent patients may experience significantly altered pacing pulses during MRI.
