A new study has revealed that individuals with the pacemaker shouldn’t use smartphones as that might stop the device form functioning and expose the users to unwanted painful shocks.

The first author of the study German Heart Center’s Dr. Carsten Lennerz said that pacemakers might mistakenly detect EMI or electromagnetic interference from smartphones as cardiac signals and stop the device briefly. Dr. Lennerz is a cardiology resident at the center’s Clinic for Heart & Circulatory Diseases.

Lennerz added that a brief pause in the functioning of pacemaker results in a pause in the patient’s cardiac rhythm, which might eventually lead to syncope. He further informed that in case of ICDs or implantable cardioverter defibrillators, external signals mimic a life-threatening condition called ventricular tachyarrhythmia, which forces the ICD to give a painful shock.

According to regulatory institutions such as the United States Food & Drug Administration (FDA) and device manufacturers, there should always be a distance of 15-20 cm between mobile phones and ICDs or pacemakers. These recommendations are made based on the findings of studies carried out ten years ago.

In recent times, we have seen a number of new cardiac devices hitting the market; these include ICDs, CRT (cardiac resynchronization therapy) and MRI compatible units. During the new study, researchers evaluated whether the previously recommended safety distance is still relevant for the new cardiac devices, smartphones, and networks.

The new study had 308 patients as participants; out of these 308 patients, 147 had pacemakers, and the remaining 161 had ICDs (65 were with CRT). All the patients got exposed to electromagnetic fields of three regular smartphones.

The smartphones were placed right on the skin covering the cardiac device and were hooked up with a radio communication tester. Here, the radio communication tester was playing the role of a mobile network station.

Must Read: Smartphones can give unwanted painful shocks to pacemaker wearers, says study

The smartphones were put through the steps of a regular calling process, which included connecting to a number, ringing, talking to the person on the other side and then disconnecting. During this entire process, the investigators continuously recorded ECGs (electrocardiograms) of the patients to check for interference. Over 3,400 tests were carried out for EMI.

It was found that just one patient out of the 308 tested was affected by the electromagnetic interference from smartphones. The researchers concluded that although interference between cardiac devices and smartphones are uncommon, it’s not impossible, which makes it necessary for patients using such devices to maintain a safe distance with smartphones. One interesting fact is that the cardiac device affected by EMI during the study was an MRI compatible unit.