Do electric cars interfere with pacemakers and defibrillators?

According to the results of a small study published in Annals of Internal Medicine, electric cars don’t interfere with cardiac implantable electronic devices (CIEDs) such as pacemakers and defibrillators.

“Electromagnetic interference (EMI) can disrupt normal function of these devices and may cause pacing inhibition, inappropriate shock delivery, or device reprogramming,” wrote researchers led by Carsten Lennerz, MD, MSc, senior physician, German Heart Centre, Munich, Germany. “Electric cars represent a potential source of EMI.”

But no one had yet determined whether electric cars posed a risk to patients with CIEDs.

For this study, Dr. Lennerz and colleagues recruited 108 patients from their electrophysiology clinic; 34 patients had pacemakers and 74 had implantable cardioverter-defibrillators. After the researchers programmed patients’ CIEDs to optimally detect EMI, they randomly assigned patients to one of four European electric cars: BMW i3, Nissan Leaf, Tesla Model S 85, or Volkswagen e-up!.

Testing involved three components:

1. Participants sat in the front seat while cars ran on a roller test bench
2. Participants charged up the same car
3. Participants rode in the car on public roads

During each test, the researchers recorded the strength of the car’s magnetic field and monitored patients’ CIEDs for tachyarrhythmia and other problems.

“We found no evidence of EMI with CIEDs,” Dr. Lennerz and coauthors concluded. “There were no episodes of over- or under-sensing, inappropriate pacing or pacing inhibition, or device reprogramming.”

The electrocardiographic recorder did detect EMI, but CIED function and programming weren’t affected.

“Electric cars are equipped with shielding to prevent EMI with onboard computer systems, which may explain our finding of low field strength inside the cars,” the authors noted. “This shielding may also be expected to protect CIEDs from EMI.”

Further testing in larger studies could uncover rare problems, and also confirm the safety of proposed “super-charging cables” that may be adopted in the future.