Electric cars safe for patients with CIEDs
Electric Cars and Electromagnetic Interference With Cardiac Implantable Electronic Devices: A Cross-sectional EvaluationLiterature - Lennerz C, O'Connor M, Horlbeck L, et al. - Ann Intern Med. 2018; published online ahead of print
Introduction and methods
Cardiac implantable electronic devices (CIEDs) may be compromised by electromagnetic interference (EMI), which causes pacing inhibition, inappropriate shock delivery, or device reprogramming. Electric cars are a potential source of EMI, but sufficient safety data are lacking as to whether their use should be restricted in patients with CIEDs.
This study set out to assess whether electric cars cause EMI and subsequent CIED dysfunction. For this purpose, 108 patients with CIEDs, which were optimally programmed to detect EMI according to established protocols , were tested for electric car use in 3 steps:
- participants sat in the front seat while cars ran on a roller test bench, to measure magnetic field strength in and around the car
- participants charged the same car in which they had sat, to measure magnetic field strength along charging cables
- investigators drove the cars on public roads, to measure magnetic field strength inside the car during open-road driving
Hybrid cars were not tested. Participants with suspected lead malfunction or CIED battery life less than 3 months were excluded from the analysis.
- Field strength was generally highest during charging (30.1-116.5 μT) and increased as the charging current increased.
- Exposure during charging was at least an order of magnitude greater than the exposure measured within 5 cm of the CIED in the front seat (2.0-3.6 μT).
- Field strength did not differ between the front and back seats. Peak field strength measured outside the cars ranged between the values measured during charging and those measured within the cars during testing.
- Field strength measured inside the cars during road driving was similar to that measured during test bench studies.
- There were no episodes of over- or under-sensing, inappropriate pacing or pacing inhibition, or device reprogramming (incidence of EMI: 0%; 95%CI: 0%-3.4%).
Electric and magnetic fields generated during operation and charging of electric cars did not affect CIED function or programming. Electric cars seem to be safe for patients with CIEDs, and restrictions for use of these cars by patients with CIEDs do not seem necessary.