Electromagnetic interference of external pacemakers by walkie-talkies and digital cellular phones: experimental study

New-generation electronic appliances and cardiac implantable electronic devices: a systematic literature review of mechanisms and in vivo studies

INTRODUCTION

Cardiac implantable electronic device (CIED) functions are susceptible to electromagnetic interference (EMI) from electromagnetic fields (EMF). Data on EMI risks from new-generation electronic appliances (EA) are limited.

OBJECTIVE

We performed a systematic literature review on the mechanisms of EMI, current evidence, and recently published trials evaluating the effect of EMF on CIEDs from electric vehicles (EV), smartphone, and smartwatch technology and summarize its safety data.

METHODS

Electronic databases, including PubMed and EMBASE, were searched for in vivo studies evaluating EMF strength and incidence between CIEDs and commercial EVs, new-generation smartphones, and new-generation smartwatches.

RESULTS

A total of ten studies (three on EVs, five on smartphones, one on smartphones, one on smartphones and smartwatches) were included in our systematic review. There was no report of EMI incidence associated with EVs or smartwatches. Magnet-containing smartphones (iPhone 12) can cause EMI when placed directly over CIEDs - thereby triggering the magnet mode; otherwise, no report of EMI was observed with other positions or smartphone models.

CONCLUSION

Current evidence suggests CIED recipients are safe from general interaction with EVs/HEVs, smartphones, and smartwatches. Strictly, results may only be applied to commercial brands or models tested in the published studies. There is limited data on EMI risk from EVs wireless charging and smartphones with MagSafe technology.

ELISA reader does not interfere by mobile phone radiofrequency radiation

BACKGROUND

The increasing number of mobile phones can physically cause electromagnetic interference (EMI) in medical environments; can also cause errors in immunoassays in laboratories. The ELISA readers are widely used as a useful diagnostic tool for Enzymun colorimetric assay in medicine. The aim of this study was to investigate whether the ELISA reader could be interfered by the exposure to the 900 MHz cell phones in the laboratory.

MATERIALS AND METHODS

Human serum samples were collected from 14 healthy donors (9 women and 5 men) and each sample was divided into four aliquots and was placed into four batches for the in-vitro quantitative determination of human chorionic gonadotropin (hCG). During colorimetric reading of the first, second, and third batches, the ELISA reader (Stat Fax 2100, Awareness Technology, Inc., USA) was exposed to 0.5, 1.0, and 2.0 W exposure of 900 MHz radiation, respectively. For the forth batch (control group), no radiation was applied. All experiments were performed comparing ELISA read out results of the I, II, and III batches with the control batch, using the Wilcoxon test with criterion level of P = 0.050.

RESULTS

The final scores in the exposed batches I, II, and III were not statistically significant relative to the control batch (P > 0.05). The results showed that 900 MHz radiation exposure did not alter the ELISA measured levels of hCG hormone in I (P = 0.219), II (P = 0.909), and III (P = 0.056) batches compared to the control batch.

CONCLUSION

This study showed that ELISA reader does not interfere by mobile phone RF radiation at a closed contact (less than 5 cm distance). However, we recommend that medical institutions discuss these issues in the context of their specific use of technologies and frame a policy that is clear and straightforward to guide staff, patients, and visitors.

Electromagnetic immunity of implantable pacemakers exposed to wi-fi devices

The purpose of this study is to evaluate the potential for electromagnetic interference (EMI) and to assess the immunity level of implantable pacemakers (PM) when exposed to the radiofrequency (RF) field generated by Wi-Fi devices. Ten PM from five manufacturers, representative of what today is implanted in patients, have been tested in vitro and exposed to the signal generated by a Wi-Fi transmitter. An exposure setup that reproduces the actual IEEE 802.11b/g protocol has been designed and used during the tests. The system is able to amplify the Wi-Fi signal and transmits at power levels higher than those allowed by current international regulation. Such approach allows one to obtain, in case of no EMI, a safety margin for PM exposed to Wi-Fi signals, which otherwise cannot be derived if using commercial Wi-Fi equipment. The results of this study mitigate concerns about using Wi-Fi devices close to PM: none of the PM tested exhibit any degradation of their performance, even when exposed to RF field levels five times higher than those allowed by current international regulation (20 W EIRP). In conclusion, Wi-Fi devices do not pose risks of EMI to implantable PM. The immunity level of modern PM is much higher than the transmitting power of RF devices operating at 2.4 GHz.

Patient safety and electromagnetic protection: a review

A systematic literature review was carried out to study patient security and possible harmful effects, immunity and interferences on medical devices, and effectiveness and transmission problems in healthcare and hospital environments due to electromagnetic interferences. The objective was to determine already-reported cases of patient security, immunity of medical devices, and transmission/reception failure in order to evaluate safety and security of patients. Literature published in the last 10 years has been reviewed by searching in bibliographic databases, journals, and proceedings of conferences. Search strategies developed in electronic databases identified a total of 820 references, with 50 finally being included. The study reveals the existence of numerous publications on interferences in medical devices due to radiofrequency fields. However, literature on effectiveness, transmission problems and measurements of electromagnetic fields is limited. From the studies collected, it can be concluded that several cases of serious interferences in medical instruments have been reported. Measures of electromagnetic fields in healthcare environments have been also reported, concluding that special protective measures should be taken against electromagnetic interferences by incoming radio waves.

Third-generation mobile phones (UMTS) do not interfere with permanent implanted pacemakers

AIMS

Third-generation mobile phones, UMTS (Universal Mobile Telecommunication System), were recently introduced in Europe. The safety of these devices with regard to their interference with implanted pacemakers is as yet unknown and is the point of interest in this study.

METHODS AND RESULTS

The study comprised 100 patients with permanent pacemaker implantation between November 2004 and June 2005. Two UMTS cellular phones (T-Mobile, Vodafone) were tested in the standby, dialing, and operating mode with 23 single-chamber and 77 dual-chamber pacemakers. Continuous surface electrocardiograms (ECGs), intracardiac electrograms, and marker channels were recorded when calls were made by a stationary phone to cellular phone. All pacemakers were tested under a "worst-case scenario," which includes a programming of the pacemaker to unipolar sensing and pacing modes and inducing of a maximum sensitivity setting during continuous pacing of the patient. Patients had pacemaker implantation between June 1990 and April 2005. The mean age was 68.4 +/- 15.1 years. Regardless of atrial and ventricular sensitivity settings, both UMTS mobile phones (Nokia 6650 and Motorola A835) did not show any interference with all tested pacemakers. In addition, both cellular phones did not interfere with the marker channels and the intracardiac ECGs of the pacemakers.

CONCLUSION

Third-generation mobile phones are safe for patients with permanent pacemakers. This is due to the high-frequency band for this system (1,800-2,200 MHz) and the low power output between 0.01 W and 0.25 W.

Temporary epicardial pacing after cardiac surgery: a practical review

The first part of this two-part review discussed the indications for various types of epicardial pacing systems and an overview of the routine care of a pacemaker-dependent patient. Dual chamber temporary pulse generators now feature many of the refinements developed initially for use in permanent pacemakers. Few of these are utilised in the immediate postoperative period, often solely due to lack of familiarity with all but basic functions. The second part of the review deals with the selection of pacing modes. Troubleshooting real and apparent pacemaker malfunctions, including manual adjustment of parameters such as the AV interval, post atrial refractory period and upper rate limit, to avoid over- and undersensing, cross-talk and pacemaker-mediated tachycardia will also be addressed.

Reliability of electromagnetic filters of cardiac pacemakers tested by cellular telephone ringing

BACKGROUND

State-of-the art cardiac pacemakers are protected against radiofrequency signals. Although there have been earlier clinical and in vitro reports of cellular phone interference with implantable devices, only a few studies have been performed in recent years. The ringing phase of digital GSM or PCS cellular phones includes a brief period of peak radiated power.

OBJECTIVES

This study tested the protection offered by electromagnetic filters of cardiac pacemakers against cellular phone ringing.

METHODS

We performed 330 consecutive tests in 158 patients at the time of routine examination in our pacemaker follow-up clinic. The programmed parameters remained unchanged before testing. During electrocardiographic monitoring, 2 single-band digital cellular phones consecutively placed over the pacemaker pocket each received a call. The phone systems tested were 1) GSM at a maximal power output of 2 W, operating on a 900 MHz carrier frequency, and 2) PCS at a maximal output of 1 W, operating on a 1800 MHz carrier frequency.

RESULTS

Interference was noted in only 5 tests, due to interaction by the GSM system with 4 unprotected pacemaker models. The GSM test was negative in 12 other tests of identical pulse generator models. The overall incidence of interference was 1.5% of tests.

CONCLUSIONS

Interference by cellular phone ringing occurred only with unprotected pacemaker models. Standard programming of these unprotected models was associated with a low incidence of interference.

Clinical review: communication and logistics in the response to the 1998 terrorist bombing in Omagh, Northern Ireland

The Omagh bombing in August 1998 produced many of the problems documented in other major incidents. An initial imbalance between the demand and supply of clinical resources at the local hospital, poor information due to telecommunication problems, the need to triage victims and the need to transport the most severely injured significant distances were the most serious issues. The Royal Group Hospitals Trust (RGHT) received 30 severely injured secondary transfers over a 5-hour period, which stressed the hospital's systems even with the presence of extra staff that arrived voluntarily before the hospital's major incident plan was activated. Many patients were transferred to the RGHT by helicopter, but much of the time the gained advantage was lost due to lack of a helipad within the RGHT site. Identifying patients and tracking them through the hospital system was problematic. While the major incident plan ensured that communication with the relatives and the media was effective and timely, communication between the key clinical and managerial staff was hampered by the need to be mobile and by the limitations of the internal telephone system. The use of mobile anaesthetic teams helped maintain the flow of patients between the Emergency Department and radiology, operating theatres or the intensive care unit (ICU). The mobile anaesthetic teams were also responsible for efficient and timely resupply of the Emergency Department, which worked well. In the days that followed many victims required further surgical procedures. Coordination of the multidisciplinary teams required for many of these procedures was difficult. Although only seven patients required admission to adult general intensive care, no ICU beds were available for other admissions over the following 5 days. A total of 165 days of adult ICU treatment were required for the victims of the bombing.

The effects of mobile phones on pacemaker function

OBJECTIVES

The electromagnetic field generated by different systems have well-recognized adverse effects on pacemaker functions. The aim of this study is to evaluate the adverse effects of mobile phones on pacemaker functions.

METHODS AND RESULTS

A total of 679 patients with permanent pacemakers were enrolled in this study. The study was performed in two steps. Pacemaker lead polarity was unipolar in the first step and bipolar in the second step. Pacemaker sensitivity was first at nominal values, it was then reduced to the minimal value for that pacemaker and tested again. Two mobile phones were symmetrically located on both sides of the pacemaker pocket with the antennas being equidistant at 50, 30, 20 and 10 cm and in close contact with the pocket. The tests were performed when both mobiles were opened, on stand-by, were receiving a call, during the call and were closed. Thirty-seven patients with pacemakers were adversely affected (5.5%) (33 VVI-R pacemakers were converted to asynchronous mode, and 3 were inhibited, 1 DDD-R pacemaker developed ventricular triggering). When the lead polarity was unipolar, the rate of adverse effect was higher when compared to the bipolar state (4.12% and 1.40%, p<0.01). The increase in sensitivity was not an independent factor on the rate of being affected (p>0.05). The rate of observing an adverse effect increased as the pacemaker got older (p<0.05).

CONCLUSIONS

Mobile phones might have adverse effects on pacemaker functions under certain conditions. This does not result in any symptoms other than the inhibition of pacemakers, and pacemaker functions return to normal when the mobile phones are removed away from the patient.

Influence des champs électromagnétiques non ionisants sur les dispositifs cardiaques médicaux implantables

AN INCREASINGLY FREQUENT PROBLEM: Since sources of electromagnetic interferences can alter the functioning of pacemakers (PM) and implantable cardioverter-defibrillators (ACD) are increasing and cover wide range of frequencies, from 0 to 300 GHz, including very low (VLF) and radio-frequencies (RF), carriers of such devices can suffer from decreased quality of life, without clinical impact, or even dangerous situations. PACEMAKERS: Pacemakers and implantable cardioverter-defibrillators are usually well protected from external interference. With pacemakers, such problems are handled fairly well and the consequences are usually benign. REGARDING DEFIBRILLATION: An interference can result in the inappropriate functioning of the device, the first consequence of which is an unexpected shock for the patient or, conversely, the lack of effective treatment when the patient most needs it. With ICD, the data in the literature suggest more attention should be paid, notably with anti-theft detector gates.

Electromagnetic interference in cardiac rhythm management devices

Clinicians caring for cardiac device patients with implanted pacemakers or cardioverter defibrillators (ICDs) are frequently asked questions by their patients concerning electromagnetic interference (EMI) sources and the devices. EMI may be radiated or conducted and may be present in many different forms including (but not limited to) radiofrequency waves, microwaves, ionizing radiation, acoustic radiation, static and pulsed magnetic fields, and electric currents. Manufacturers have done an exemplary job of interference protection with device features such as titanium casing, signal filtering, interference rejection circuits, feedthrough capacitors, noise reversion function, and programmable parameters. Nevertheless, EMI remains a real concern and a potential danger. Many factors influence EMI including those which the patient can regulate (eg, distance from and duration of exposure) and some the patient cannot control (eg, intensity of the EMI field, signal frequency). Potential device responses are many and range from simple temporary oversensing to permanent device damage Several of the more common EMI-generating devices and their likely effects on cardiac devices are considered in the medical, home, and daily living and work environments.

Mobile phone interference with medical equipment and its clinical relevance: a systematic review

OBJECTIVE

To conduct a systematic review of studies on clinically relevant digital mobile phone electromagnetic interference with medical equipment.

DATA SOURCES

MEDLINE and SUMSEARCH were searched for the period 1966-2004. The Cochrane Library and Database of Abstracts of Reviews of Effects were also searched for systematic reviews.

STUDY SELECTION

Studies were eligible if published in a peer-reviewed journal in English, and if they included testing of digital mobile phones for clinically relevant interference with medical equipment used to monitor or treat patients, but not implantable medical devices.

DATA SYNTHESIS

As there was considerable heterogeneity in medical equipment studied and the conduct of testing, results were summarised rather than subjected to meta-analysis.

RESULTS

Clinically relevant electromagnetic interference (EMI) secondary to mobile phones potentially endangering patients occurred in 45 of 479 devices tested at 900 MHz and 14 of 457 devices tested at 1800 MHz. However, in the largest studies, the prevalence of clinically relevant EMI was low. Most clinically relevant EMI occurred when mobile phones were used within 1 m of medical equipment.

CONCLUSIONS

Although testing was not standardised between studies and equipment tested was not identical, it is of concern that at least 4% of devices tested in any study were susceptible to clinically relevant EMI. All studies recommend some type of restriction of mobile phone use in hospitals, with use greater than 1 m from equipment and restrictions in clinical areas being the most common.

Temporary Pacemakers in Critically Ill Patients

Temporary cardiac pacing provides electrical stimulation to a heart compromised by disturbances in the conduction system causing hemodynamic instability. The use of a temporary pacemaker to treat a bradydysrhythmia or in some cases, a tachydysryhthmia, is undertaken when the condition is temporary and a permanent pacemaker is not necessary or available in a timely fashion. Temporary cardiac pacing is utilized in acute situations and for critically ill patient populations requiring immediate therapy. This article discusses the various indications and contraindications to temporary cardiac pacing therapy, reviews the different modalities of temporary pacemakers, and outlines critical considerations in the management of patients being treated with a temporary pacemaker.

Electronic medical devices: a primer for pathologists

CONTEXT

Electronic medical devices (EMDs) with downloadable memories, such as implantable cardiac pacemakers, defibrillators, drug pumps, insulin pumps, and glucose monitors, are now an integral part of routine medical practice in the United States, and functional organ replacements, such as the artificial heart, pancreas, and retina, will most likely become commonplace in the near future. Often, EMDs end up in the hands of the pathologist as a surgical specimen or at autopsy. No established guidelines for systematic examination and reporting or comprehensive reviews of EMDs currently exist for the pathologist.

OBJECTIVE

To provide pathologists with a general overview of EMDs, including a brief history; epidemiology; essential technical aspects, indications, contraindications, and complications of selected devices; potential applications in pathology; relevant government regulations; and suggested examination and reporting guidelines.

DATA SOURCES

Articles indexed on PubMed of the National Library of Medicine, various medical and history of medicine textbooks, US Food and Drug Administration publications and product information, and specifications provided by device manufacturers.

STUDY SELECTION

Studies were selected on the basis of relevance to the study objectives.

DATA EXTRACTION

Descriptive data were selected by the author.

DATA SYNTHESIS

Suggested examination and reporting guidelines for EMDs received as surgical specimens and retrieved at autopsy.

CONCLUSIONS

Electronic medical devices received as surgical specimens and retrieved at autopsy are increasing in number and level of sophistication. They should be systematically examined and reported, should have electronic memories downloaded when indicated, will help pathologists answer more questions with greater certainty, and should become an integral part of the formal knowledge base, research focus, training, and practice of pathology.

Electromagnetic interference of GSM mobile phones with the implantable deep brain stimulator, ITREL-III

BACKGROUND

The purpose was to investigate mobile phone interference with implantable deep brain stimulators by means of 10 different 900 Mega Hertz (MHz) and 10 different 1800 MHz GSM (Global System for Mobile Communications) mobile phones.

METHODS

All tests were performed in vitro using a phantom especially developed for testing with deep brain stimulators. The phantom was filled with liquid phantom materials simulating brain and muscle tissue. All examinations were carried out inside an anechoic chamber on two implants of the same type of deep brain stimulator: ITREL-III from Medtronic Inc., USA.

RESULTS

Despite a maximum transmitted peak power of mobile phones of 1 Watt (W) at 1800 MHz and 2 W at 900 MHz respectively, no influence on the ITREL-III was found. Neither the shape of the pulse form changed nor did single pulses fail. Tests with increased transmitted power using CW signals and broadband dipoles have shown that inhibition of the ITREL-III occurs at frequency dependent power levels which are below the emissions of GSM mobile phones. The ITREL-III is essentially more sensitive at 1800 MHz than at 900 MHz. Particularly the frequency range around 1500 MHz shows a very low interference threshold.

CONCLUSION

These investigations do not indicate a direct risk for ITREL-III patients using the tested GSM phones. Based on the interference levels found with CW signals, which are below the mobile phone emissions, we recommend similar precautions as for patients with cardiac pacemakers: 1. The phone should be used at the ear at the opposite side of the implant and 2. The patient should avoid carrying the phone close to the implant.

Are mobile phones harmful?

There is increasing public interest in health risks of mobile phone use. Although there is a vast body of material on the biological effects of radiofrequency fields, current risk assessment is still limited. The article describes several hypotheses and results of biological effects such as thermal effect, genetic and carcinogenic effects and cancer related investigations. Mobile phones transmit and receive waves of frequencies mainly at 800-1800 MHz. Findings on the thermal effect of acute exposure to radiofrequency fields were consistent, resulting in an increase of cellular, tissue or body temperature by 1 degree C or more. Guidelines for risk limits are based on this thermal effect. Experimental investigation suggests that radiofrequency fields are not tumor initiators and that if they are related to carcinogenicity, this would be by tumor promotion or by increasing the uptake of carcinogens in cells. Implications of these experimental results on public health concerns are yet unclear. Few epidemiological studies are available on the use of mobile phones or on the radiofrequency exposure and the development of cancer. Most of these studies have no or little quantitative exposure data and they are limited by the small number of observations. Large epidemiological studies are necessary in order to investigate the use of mobile phones on the development of cancer. It should be emphasized that even a small elevated risk may have a large implication for public health, as the use of mobile phones and the exposure is rapidly increasing.