A new research has revealed that people wearing pacemakers should keep a safe distance from smartphones in order to avoid unwanted painful shocks or pauses in function.

According to researchers, smartphones can cause both pauses in a pacemaker’s function as well as painful shocks in the wearers.

The study was performed primarily on 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 currently in use include ICDs, cardiac resynchronisation therapy (CRT) and MRI compatible devices.

Study’s first author Dr. Carsten Lennerz, cardiology resident in the Clinic for Heart and Circulatory Diseases, German Heart Centre, Munich, Germany, said that electromagnetic interference (EMI) from smartphones is mistakenly detected by pacemakers.

They detect EMI as a cardiac signal, which causes them to stop working briefly, causing a pause in the cardiac rhythm of the pacing.

This might result in syncope, which is temporary loss of consciousness caused by a fall in blood pressure. The external signal from smartphone mimics a life threatening ventricular tachyarrhythmia for implantable cardioverter defibrillators (ICDs). This can lead ICD to deliver a painful shock.

For the study, total 308 patients (147 pacemakers and 161 ICDs, including 65 CRTs) were exposed to the electromagnetic field of three common smartphones. The phones that were placed on the skin directly above the cardiac device were connected to a radio communication tester, which works like a mobile network station.

A safety distance of 15 to 20 cm between pacemakers or ICDs and mobile phones has been recommended by device manufacturers and regulatory institutions, including the US Food and Drug Administration (FDA).