How 'smartphones' can be harmful for people who wear cardiac device

People who wear cardiac device need to keep a distance from smartphones to avoid unwanted painful shocks or pauses in function, suggests a new study.

Dr. Carsten Lennerz, first author and cardiology resident at German Heart Centre, Munich, Germany, said that pacemakers can mistakenly detect electromagnetic interference (EMI) from smartphones as a cardiac signal, causing them to briefly stop working. This leads to a pause in the cardiac rhythm of the pacing dependent patient and may result in syncope.

Device manufacturers and regulatory institutions including the US Food and Drug Administration (FDA) recommend a safety distance of 15 to 20 cm between pacemakers or ICDs and mobile phones. The advice is based on studies performed primarily in pacemakers 10 years ago. Since then smartphones have been introduced and mobile network standards have changed from GSM to UMTS and LTE. New cardiac devices are now in use including ICDs, cardiac resynchronisation therapy (CRT) and MRI compatible devices.

Lennerz said that interference between smartphones and cardiac devices is uncommon but can occur so the current recommendations on keeping a safe distance should be upheld. Interestingly, the device influenced by EMI in our study was MRI compatible which showed that these devices were also susceptible.

Dr. Katia Dyrda, a cardiologist at Montreal Heart Institute, University of Montreal, Dyrda added there was no need for patients with a pacemaker or ICD to avoid crossing under high voltage power lines (> 230 kV) but patients should avoid staying in a stationary position underneath them. Passing near pylons rather than between two pylons mitigates exposure to the electric field because the wires sag in the middle and the field is higher at this location.