Cardiac Patients Warned of Smartphone Dangers

An announcement this week by the European Society of Cardiology reveals potential dangers for those wearing cardiac devices, as they may be affected by electromagnetic interference (EMI) from smartphones.

The research is being presented at the joint meeting of the European Heart Rhythm Association (EHRA) and the European Society of Cardiology (ESC) at the annual CARDIOSTEM conference being held in Milan, Italy.

The study aims to confirm previous research conducted a decade ago, that examined the potential for interference by smartphone devices on patients with implanted cardiac devices, which include pacemakers, implantable cardioverter defibrillators (ICDs) and cardiac resynchronization therapy (CRT) devices. Researchers were curious if new technology afforded by today's smartphones might still pose threats to such individuals.

"Pacemakers can mistakenly detect electromagnetic interference (EMI) from smartphones as a cardiac signal, causing them to briefly stop working," says lead author Dr. Carsten Lennerz, a resident in the Clinic for Heart and Circulatory Diseases at the German Heart Centre in Munich, Germany. "This leads to a pause in the cardiac rhythm of the pacing dependent patient and may result in syncope. For implantable cardioverter defibrillators (ICDs) the external signal mimics a life threatening ventricular tachyarrhythmia, leading the ICD to deliver a painful shock."

Previous guidelines set safety distances between phones and cardiac devices at 15 to 20 cm - about 6 - 8 inches. To test whether patients might still be at risk, researchers exposed 308 patients (147 pacemakers and 161 ICDs) to electromagnetic fields from three common smartphones: Samsung Galaxy 3, Nokia Lumia, and HTC One XL. The phones were placed on the patients' skin directly over their cardiac devices.

"From earlier studies we know that the most vulnerable phases of a call are ringing and connecting to the network, not talking, so it was important to analyze these separately," Lennerz says. 

Only one out of the 308 subjects experienced disruption in the performance of their cardiac device. Regardless of the low risk, Lennerz warns patients to heed previous safety guidelines.

"Interference between smartphones and cardiac devices is uncommon but can occur, so the current recommendations on keeping a safe distance should be upheld."

"Nearly everyone uses smartphones and there is the possibility of interference with a cardiac device if you come too close" said Professor Christof Kolb, who is head of the Department of Electrophysiology at the German Heart Centre and a coauthor of the study. "Patients with a cardiac device can use a smartphone but they should not place it directly over the cardiac device."

"That means not storing it in a pocket above the cardiac device. They should also hold their smartphone to the ear opposite to the side of the device implant."