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The role of environmental electromagnetic interference on pacemakers, ICDs and CRT devices will be under the environmental spotlight at a Symposium this afternoon when a session jointly organised with the Asian Pacific Society of Cardiology will consider the impact of mobile phones, security devices, portable headphones and other household devices.
‘The reality of modern living is that we’re surrounded by multiple devices which communicate with each other wirelessly,’ explains Mohammad Amin, from the Cardiac Centre, Bahrain. ‘Problems can arise when this technology coexists in the same environment as heart devices. Complete avoidance is impractical, so it’s important for patients to get advice before having devices implanted. We reassure them that the environment is safe so long as they stick to a few simple rules and remain vigilant for risks.’Use of pacemakers and ICDs in Europe is still rising. Data from EUCOMED, the organisation representing the European medical device industry, show the number of pacemakers per million inhabitants in Europe rising from 738 in 2005 to 923 in 2012, while the number of defibrillators rose from 70 per million in 2005 to 167 in 2012. Such increases have coincided with similar advances in wireless technologies and sharp rises in background levels of electromagnetic fields.
Because cardiac electronic devices are able to sense electrical activity and use electromagnetic waves for communication, they are susceptible to electromagnetic interference (EMI) from surrounding radiation. While modern cardiac devices have built-in features to protect them from interference, including hermetic shielding and filters designed to reject EMI, interference can still take place.
If devices do detect EMIs, explains Haran Burri, from University Hospital, Geneva, this can result in either inhibition of pacing (ie, no pacing, even in a patient without his own rhythm, which is life threatening), asynchronous pacing (which does not take into account the patient’s intrinsic beats) or inappropriate ICD therapy (shocks because the device believes there is an arrhythmia).
Device manufacturers and regulatory authorities currently recommend safety distances of 15 cm between pacemakers or ICDs and mobile phones. Such recommendations are based on studies from over a decade ago, which described EMI between cell phones and pacemakers before the advent of effective filters. ‘The device companies continue to issue these recommendations in order to stay conservative, despite voluntary testing of pacemakers and ICDs to ensure compatibility with cell phones without any restrictions of distance,’ says Burri.
In a study presented earlier this year 308 ICD patients were exposed to electromagnetic fields induced by three common smartphones placed directly above the device. Results showed that one patient was affected by EMI when the patient’s MRI-compatible ICD mis-detected electromagnetic waves from two of the smartphones.
‘The study needs further investigation and should not lead to hasty conclusions,’ says Burri. ‘The overwhelming evidence does not show any interference whatsoever between modern pacemakers, ICDs and cell phones.’ Burri found no evidence of cell phone interference in his own study in 63 ICD patients., and says: ’Recommendations regarding cell phone use should be evidence based, pragmatic, and allow device patients to live as normally as possible without unnecessary stress.’
While inappropriate ICD shocks and pacemaker inhibition have been associated with prolonged (several minutes) exposure to electromagnetic security systems (such as antishoplifting gates and metal detectors), such problems are rarely seen in exposures lasting 10 to 15 seconds ‘The general advice is for patients to walk briskly across electronic surveillance devices,’ says Chi-KeongChing, from National Heart Centre, Singapore. If scanning with a hand-held metal detector is necessary, he adds, patients should warn security staff and ask them not to hold the metal detector near the device any longer than necessary, or ask for an alternative form of personal search.
While portable digital music devices (such as iPods) and headsets (which contain magnets) can interfere with cardiac devices, risks are low. ‘There aren’t any actual case reports showing adverse events,’ says Amin. The general recommendations, he adds, are to keep media players and headsets at least 15 cm from the device and to avoid draping headphones around their neck over the device.
Portable media players also must be turned off when patients go to the clinic for regular device follow-up appointments. ‘The issue here is that portable media players emit electromagnetic waves in the same range as used for device interrogation. While this doesn’t affect pacemaker function, it can affect interrogation readings,’ cautions Amin.
Environmental effects on patients with pacemakers and ICD, 29 Aug 13:30—15:00 Algiers - Village 4
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