Cardiac device wearers should be wary of smartphones

A new study has suggested that people who have cardiac devices should try and maintain a safe distance between themselves and smartphones.

Dr Carsten Lennerz, first author and cardiology resident in the Clinic for Heart and Circulatory Diseases at the German Heart Centre in Munich, presented the research at the European Heart Rhythm Association (EHRA) Eurospace Cardiostim 2015.

This 'safe distance' is to avoid unwanted painful shocks or pauses in function of the cardiac devices, Dr Lennerz states.

He said pacemakers can mistakenly detect electromagnetic interference (EMI) from smartphones as a cardiac signal, causing them to briefly stop working. This leads to a long pause in the cardiac rhythm of the pacing dependent patient and may even result in a short loss of consciousness.

Some devices such as implantable cardioverter defibrillators (ICDs) react by delivering a painful shock to the user as they interrupt the external signal as a life-threatening ventricular tachyarrhythmia.

In his study, Dr Lennerz looked at whether the current guidance was sufficient to protect people, especially with newer smartphones. He found a total of 308 patients (147 pacemakers and 161 ICDs, including 65 CRTs) were exposed to the electromagnetic field of three common smartphones, which were placed on the skin directly above the cardiac device.

Each smartphone was linked up to a radio communication tester, which resembles a mobile network station. The researchers then put the smartphones through the standard ringing process, which were performed at the maximum transmission power and at 50 Hz, a frequency known to influence cardiac implantable electronic devices. 

Current regulations recommend a safety distance of 15 to 20 cm between pacemakers or ICDs and mobile phones, which is based on research conducted nearly ten years ago. However, a lot of developments have been made in smartphones, as well as mobile network standards having changed.

The research used electrocardiograms (ECGs) to monitor any interference, and found that 0.3 per cent of the 3,400 tests conducted were affected by the smartphones. 

Dr Lennerz said: "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 shows that these devices are also susceptible."

Last author Professor Christof Kolb, head of the Department of Electrophysiology at the German Heart Centre, said most people now use a smartphone so if there is even the smallest possibility of interference with cardiac devices it needs to be analysed.

He said: "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."

Posted by Edward Bartel

Health News is provided by Adfero in collaboration with Spire Healthcare. Please note that all copy above is ©Adfero Ltd. and does not reflect views or opinions of Spire Healthcare unless explicitly stated. Additional comments on the page from individual Spire consultants do not necessarily reflect the views or opinions of other consultants or Spire Healthcare.

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