E-Cigarette Hazards Can Include ICD Magnet Reversion, Maybe Leaving Patient Vulnerable

March 16, 2020

Call them e-cigarettes, vapes, or vaporizers, some can pose a little-discussed potential threat to patients with a cardiac implantable electronic device (CIED) that has little to do with nicotine's effects on the heart and lungs.

Many of the popular nicotine-delivery systems, across numerous brands, contain magnets that serve different functions; among them is a way to keep the detachable components of the device together or dock it to a power source.

Vaporizers are very portable and often pen-shaped, making them ideal for carrying in the shirt breast pocket. But that position can place them adjacent to implanted CIEDs, and more specifically, near their magnetic switches, potentially altering their functionality.

A new report documents a case of likely repeated magnetic interference from a vaporizer (JUUL Labs, San Francisco) affecting a primary-prevention implantable cardioverter-defibrillator (ICD) in a man with depressed left ventricular function and a history of cardiac sarcoidosis.

The vaporizer's magnets apparently caused reversion of the ICD; that is, it probably activated the magnetic switch that temporarily suspended the device's antitachycardia protection.

Instances of magnetic inference of medical-device functionality from everyday environmental sources periodically show up in the literature. For example, two cases of CIED interference from magnets in the head straps of continuous positive airway pressure (CPAP) masks recently appeared in PACE.

The current patient had received a dual-chamber ICD as an upgrade from a device that had been implanted about 7 years earlier and was approaching its recommended elective replacement time, notes the report, published in the March issue of Heart Rhythm Case Reports, with lead author Julie B. Shea, MS, Brigham and Women's Hospital, Boston.

"Following his admission, the patient contacted our office to report that he heard his device 'beep' several times, which he described as an audible 'single steady tone'," the group writes. The patient reported that there had been no symptoms or shocks associated with the sounds. Interrogation of the device revealed that it had not been recently reprogrammed.

Data from remote transmissions provided by the ICD's manufacturer, Medtronic, confirmed that there had been four recent magnet interactions with the device, which corresponded in time to the sounds the patient reported.

"The patient recalled using his e-cigarette, which he frequently stored in his left breast pocket overlying the device." Then, "we held the JUUL vape device up to his ICD, which elicited the steady magnet tone," the authors write.

"While no serious injury was observed as a consequence of the magnet reversion and suspension of ICD therapies in this particular case, there is potential for unintentional temporary programming and arrhythmic complications when an electronic cigarette is placed in close proximity to an ICD or pacemaker."

They continue: "Suspension of tachycardia therapies from inadvertent magnet application to the ICD could have fatal consequences, if coincidental with a tachycardia episode."

The patient, they write, "was educated about the magnet feature of the ICD system and the importance of keeping any type of magnet at least 6 inches from the device."

In a demonstration of the observed unintentional ICD reversion's potential clinical impact, "the patient subsequently had a syncopal event in February 2019 corresponding to a remote transmission demonstrating an episode of ventricular tachycardia that required ICD therapy for termination."

They conclude: "It is incumbent on electrophysiologic practitioners to be aware of such device-device interactions to avoid potential negative outcomes in patients."

Shea has "no financial disclosures." Conflict statements for the other authors are in the report.

HeartRhythm Case Rep. 2020;6:121-123. Full text

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