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Interference with cardiac pacemakers by magnetic resonance imaging: are there irreversible changes at 0.5 Tesla?
C Vahlhaus1, T Sommer, T Lewalter
1Medizinische Universitätsklinik und Poliklinik II, Rheinische Friedrich-Wilhelms-Universität Bonn, Germany. Vahlhaus@uni-muenster.de
Abstract:
The safety and feasibility of magnetic resonance imaging (MRI) in patients with cardiac pacemakers is an issue of gaining significance. The effect of MRI on patients' pacemaker systems has only been analyzed retrospectively in some case reports. Therefore, this study prospectively investigated if MRI causes irreversible changes in patients' pacemaker systems. The effect of MRI at 0.5 Tesla on sensing and stimulation thresholds, lead impedance and battery voltage, current, and impedance was estimated during 34 MRI examinations in 32 patients with implanted pacemakers. After measurements at baseline and with documentation of intrinsic rhythm and modification of the pacing mode, patients underwent MRI. The rest of the function time of the pacemaker was calculated. Measurements were again performed after 99.5 +/- 29.6 minutes (mean +/- SD), immediately after MRI examination, and 3 months later. Lead impedance and sensing and stimulation thresholds did not change after MRI. Battery voltage decreased immediately after MRI and recovered 3 months later. Battery current and impedance tended to increase. The calculated rest of function time did not change immediately after MRI. MRI affected neither pacemaker programmed data, nor the ability to interrogate, program, or use telemetry. Surprisingly, in the gantry of the scanner, temporary deactivation of the reed switch occurred in 12 of 32 patients when positioned in the center of the magnetic field. Missing activation of the reed switch through the static magnetic field at 0.5 Tesla is not unusual. MRI at 0.5 Tesla does not cause irreversible changes in patients' pacemaker systems.
Insights
This study found that 0.5 Tesla magnetic resonance imaging (MRI) does not cause irreversible changes in cardiac pacemaker systems. Pacemaker function and data remained unaffected, ensuring patient safety during MRI scans.
Area of Science:
- Cardiology
- Medical Imaging
- Biomedical Engineering
Background:
- The safety of magnetic resonance imaging (MRI) for patients with cardiac pacemakers is a growing concern.
- Previous analyses of MRI's effects on pacemakers were retrospective, necessitating prospective investigation.
Purpose of the Study:
- To prospectively evaluate the safety and feasibility of 0.5 Tesla MRI in patients with cardiac pacemakers.
- To determine if MRI induces irreversible changes in pacemaker system parameters.
Main Methods:
- Prospective study involving 32 patients with implanted pacemakers undergoing 34 MRI examinations at 0.5 Tesla.
- Measurements of sensing/stimulation thresholds, lead impedance, and battery parameters were taken before, immediately after, and 3 months post-MRI.
- Pacemaker programmed data and interrogation capabilities were also assessed.
Main Results:
- No significant changes were observed in lead impedance, sensing, or stimulation thresholds post-MRI.
- Battery voltage showed a temporary decrease immediately after MRI, with recovery at 3 months; battery current and impedance tended to increase.
- Pacemaker programmed data, interrogation, and telemetry functions remained unaffected; however, temporary reed switch deactivation occurred in some patients within the scanner's magnetic field.
Conclusions:
- 0.5 Tesla MRI is safe and feasible for patients with cardiac pacemakers, as it does not cause irreversible system damage.
- While temporary reed switch deactivation can occur, it does not lead to lasting adverse effects on pacemaker function.
- The study supports the use of 0.5 Tesla MRI in pacemaker patients when clinically indicated.