An Interchangeability Test Method for Developing IPG Impedance Equivalency Evidence for Cardiac Implantable
Hongbae Jeong1, Andrew Smith2, Ananda Kumar1
1Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, Maryland, USA.
Magnetic Resonance in Medicine
|April 26, 2026
Summary
A new test evaluates radiofrequency (RF) heating for cardiac implantable electronic devices (CIEDs) with mixed-manufacturer parts. This simplified test allows patients with replaced implantable pulse generators (IPGs) to safely undergo MRI scans.
Area of Science:
- Biomedical Engineering
- Medical Imaging Safety
- Electromagnetic Compatibility
Background:
- Patients with cardiac implantable electronic devices (CIEDs) often have components replaced over time, leading to mixed-manufacturer systems.
- Mixed-manufacturer CIED systems may present unknown risks, particularly concerning radiofrequency (RF)-induced heating during MRI exposure.
- Current methods for evaluating RF safety in these mixed systems are not efficient.
Purpose of the Study:
- To develop a least-burdensome method for evaluating RF safety in CIEDs with mixed-manufacturer components.
- To establish an implantable pulse generator (IPG) equivalency test to support MR Conditional labeling for mixed-manufacturer systems.
- To determine if replacing an original IPG with a third-party model significantly alters RF-induced heating.
Main Methods:
- Measured the transfer function of pacing leads in original (LeadA + IPGA) and mixed-manufacturer systems (LeadA + IPGB or IPGC).
- Compared deposited power near the lead tip under 50 Ω and open-end conditions.
- Measured lead and IPG impedances at 64 and 128 MHz.
Main Results:
- Lead tip heating differences between original and third-party IPG configurations were not statistically significant (p < 0.001).
- RF-induced heating responses remained within measurement uncertainty for most tested conditions, including small IPG impedance changes (< 2.5 Ω) in systems with overall impedance > 80.2 Ω.
- Significant heating deviations occurred only under specific conditions, such as with a 50 Ω resistor or certain open-end scenarios.
Conclusions:
- A simplified IPG impedance equivalency test was developed to facilitate MRI access for patients with mixed-manufacturer CIEDs.
- This test effectively assesses whether IPG replacement significantly increases RF-induced heating compared to the original system.
- The method supports leveraging existing single-manufacturer MR Conditional labeling for mixed-manufacturer CIED systems.
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