Interactions between pacemakers and security systems

Electromagnetic interference from automobile passive keyless entry in cardiovascular implantable electronic devices

INTRODUCTION

The automobile passive keyless entry (PKE) system is a potential source of electromagnetic interference (EMI). We aim to determine the incidence and significance of EMI from automobile PKE system in cardiovascular implantable electronic device (CIED) patients.

METHODS

This was a single-center cross-sectional study conducted at Maharaj Nakorn Chiang Mai hospital, Thailand. Patients with CIED were instructed to lock and unlock two automobiles using the PKE system. Any EMI or arrhythmias were detected by CIED interrogation and single-lead electrocardiogram event recorder. We also used a spectrum analyzer to identify the automobiles working frequency bandwidth.

RESULTS

There was a total of 102 CIED patients. Device types included 48.0% defibrillators, 37.3% permanent pacemakers, and 14.7% cardiac resynchronization therapy device. Both interrogated data from device and event monitor revealed no incidence of EMI during the PKE activation. We failed to identify the working frequency bandwidth of the two studied cars due to very low signal strength, thus blended in with the background noise.

CONCLUSIONS

Automobile PKE systems transmitted very low power signals. Therefore, under normal circumstances, CIED patients can use automobile PKE system safely without any EMI regardless of key fob positions in relation to the CIED pulse generator.

TRIAL REGISTRATION

The study was registered at ClinicalTrials.gov (https://clinicaltrials.gov), and the identification number is NCT03016390.

Electromagnetic interference in cardiac electronic implants caused by novel electrical appliances emitting electromagnetic fields in the intermediate frequency range: a systematic review

Electromagnetic fields (EMF) in the intermediate frequency (IF) range are generated by many novel electrical appliances, including electric vehicles, radiofrequency identification systems, induction hobs, or energy supply systems, such as wireless charging systems. The aim of this systematic review is to evaluate whether cardiovascular implantable electronic devices (CIEDs) are susceptible to electromagnetic interference (EMI) in the IF range (1 kHz-1 MHz). Additionally, we discuss the advantages and disadvantages of the different types of studies used to investigate EMI. Using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement, we collected and evaluated studies examining EMI in in vivo studies, in vitro studies (phantom studies, benchmark tests), and simulation studies. Our analysis revealed that cardiac implants are susceptible to malfunction induced by EMF in the IF range. Electromagnetic interference may in particular be provoked by security systems and induction hobs. The results of the studies evaluated in this systematic review further indicate that the likelihood for EMI is dependent on exposure-related parameters (field strength, frequency, and modulation) and on implant- as well as on lead-related parameters (model, type of implant, implant sensitivity setting, lead configuration, and implantation site). The review shows that the factors influencing EMI are not sufficiently characterized and EMF limit values for CIED patients cannot be derived yet. Future studies should therefore, consider exposure-related parameters as well as implant- and lead-related parameters systematically. Additionally, worst-case scenarios should be considered in all study types where possible.

Effects of external electrical and magnetic fields on pacemakers and defibrillators: from engineering principles to clinical practice

The overall risk of clinically significant adverse events related to EMI in recipients of CIEDs is very low. Therefore, no special precautions are needed when household appliances are used. Environmental and industrial sources of EMI are relatively safe when the exposure time is limited and distance from the CIEDs is maximized. The risk of EMI-induced events is highest within the hospital environment. Physician awareness of the possible interactions and methods to minimize them is warranted.

Interference between active implanted medical devices and electromagnetic field emitting devices is rare but real: results of an incidence study in a population of physicians in France

BACKGROUND AND OBJECTIVE

Assessing the behavior of active implanted medical devices (AIMDs) in response to electromagnetic field (EMF) transmitters is a current issue of great importance. Given the numerous telecommunication systems and our lack of knowledge as to the impact of electromagnetic effects, this study investigated the reality of possible AIMD disturbance by EMFs by interviewing health professionals.

METHOD

A self-administered postal questionnaire was sent to almost 5,000 physicians in five specialties: cardiology; endocrinology; ears, nose, and throat; urology; and neurology. It collected data on the existence and annual number of incidents observed and the conditions under which they occurred, the EMF sources involved, and the means of managing the malfunctions.

RESULTS

A total of 1,188 physicians agreed to participate. Sixteen percent of participants reported cases of implant failure, three-quarters of whom, mainly in cardiology, reported rates of at least one incident per year-amounting to more than 100 incidents per year in all. Severity appeared to be moderate (discomfort or transient symptoms), but frequently required resetting or, more rarely, replacing the device. Some serious incidents were, however, reported. The sources implicated were basically of two types: electronic security systems (antitheft and airport gates) and medical electromagnetic radiation devices. These incidents were poorly reported within the public health system, preventing follow-up and effective performance of alert and surveillance functions.

CONCLUSION

Although minor, the risk of interference between EMF sources and AIMDs is real and calls for vigilance. It particularly concerns antitheft and airport security gates, though other sources may also cause incidents.

Experimental study on malfunction of pacemakers due to exposure to different external magnetic fields

PURPOSE

Cardiac pacemaker malfunction due to exposure to magnetic fields may cause serious problems in some work environments for workers having cardiac pacemakers. The aim of this study was to find the magnetic field interference thresholds for several commonly used pacemaker models.

METHODS

We investigated 16 pacemakers from three different manufacturers with the frequency range of 2 to 1,000 Hz, using sinusoidal, pulse, ramp, and square waveforms. The magnetic fields were produced by a computer-controlled Helmholtz coil system.

RESULTS

Pacemaker malfunction occurred in six of 16 pacemakers. Interaction developed almost immediately after high-intensity magnetic field exposure started. With each waveform, at least two pacemakers exhibited interference. In most exposure settings, there was no interference at magnetic field levels below the international occupational safety limits. Nevertheless, some frequencies using ramp or square waveforms interfered with pacemakers even at levels below public exposure limits. The occurrence of interference depended greatly on the waveform, frequency, magnetic field intensity, and the sensing configuration of the pacemaker. Unipolar configurations were more susceptible for interference than the bipolar ones. In addition, magnetic fields perpendicular to the pacemaker loops were more likely to cause interference than parallel fields.

CONCLUSION

There is a need for further investigations on pacemaker interference caused by different external magnetic fields to ensure safe working environment to workers with a pacemaker.

X-ray radiation causes electromagnetic interference in implantable cardiac pacemakers

BACKGROUND

X-rays are not thought to cause electromagnetic interference (EMI) in implantable cardiac pacemakers. However, x-ray radiation during computed tomography (CT) scanning has been reported to cause EMI in some implantable cardiac pacemakers. The objectives of this study were to identify the location within the pacemakers where x-ray radiation causes EMI and to investigate the association of EMI with the x-ray radiation conditions.

METHODS

We verified the location where x-ray radiation caused EMI using a CT scanner and conventional radiographic x-ray equipment. An inhibition test and an asynchronous test were performed using five types of implantable cardiac pacemakers.

RESULTS

X-ray radiation inhibited the pacing pulses of four types of implantable cardiac pacemakers when the body of each implantable cardiac pacemaker, containing a complementary metal-oxide semiconductor (CMOS), was scanned using a CT scanner. We confirmed that x-ray-induced EMI depends on the x-ray radiation conditions, that is, the tube voltage, tube current, x-ray dose, and direction of x-ray radiation, as well as the sensing thresholds of the implantable cardiac pacemakers.

CONCLUSIONS

X-ray radiation caused EMI in some implantable cardiac pacemakers, probably because the CMOS component was irradiated. The occurrence of EMI depended on the pacemaker model, sensing threshold of the pacemaker, and x-ray radiation conditions.

Patients' experiences of daily living with a pacemaker: a grounded theory study

The purpose of this study was to examine patients' experiences of daily living with a pacemaker. A total of 13 pacemaker patients (seven women) aged 22-82 (mean = 59.2) years were interviewed. The informants had had a pacemaker from 0.5 to 33 (mean 13.1) years. The grounded theory method was the basis for collection and analysis of the data. The results of the analysis of the semi-structured interviews showed that variations in 'perceived social participation' and 'emotional state', the two core categories, were related to four qualitatively different ways of experiencing daily living after pacemaker implantation.

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.

Electromagnetic Interference of Implantable Unipolar Cardiac Pacemakers by an Induction Oven

Induction ovens have been reported to exert electromagnetic interference on implanted cardiac pacemakers. In an attempt to quantitatively investigate the electromagnetic interference caused by an induction oven on implantable unipolar cardiac pacemakers, we measured the distribution profile of the magnetic field intensity, both with and without a pan on the induction oven. We also performed the inhibition test and asynchronous test using four kinds of pacemakers housed in the standardized Irnich human body model, and measured the maximal distance from the induction oven up to which the interference occurred. In the pan-detection mode of the oven in the absence of a pan, the distribution profile of the magnetic field intensity peaked at the center of the cooking plate, and during induction heating of a pan placed on the induction oven, it was the largest at the circular top-edge of the pan. Pacemaker pulses were inhibited by the induction oven, or generated by the reversion mechanism. The maximal interference distance from the oven was 34 cm for one of the pacemakers. Thus, the safe distance from an induction oven of a patient with an implanted cardiac pacemaker is considered to be 50 cm or more. In conclusion, in the pan-detection mode of the oven in the absence of a pan, the distribution profile of the magnetic field intensity peaked at the center of the cooking plate, and during the induction heating of a pan placed on the oven, it peaked at the circular edge of the pan. The induction oven asynchronized or generated pulses in implantable unipolar cardiac pacemakers up to a maximal distance of 34 cm from the induction oven.

Implantable Cardiac Pacemaker Electromagnetic Compatibility Testing in a Novel Security System Simulator

This paper describes a novel simulator to perform electromagnetic compatibility (EMC) tests for active implantable medical devices (AIMDs) with electromagnetic fields emitted by security systems. The security system simulator was developed in response to over 100 incident reports over 17 years related to the interference of AIMD's with security systems and the lack of a standardized test method. The simulator was evaluated regarding field homogeneity, signal distortion, and maximum magnetic field strength levels. Small three-axis probes and a three-axis scanning system were designed to determine the spatial and temporal characteristics of the fields emitted by 12 different types of walk through metal detectors (WTMDs). Tests were performed on four implanted pacemakers with a saline phantom and correlated to a newly developed test method performed "in air" (without the phantom). Comparison of the simulator thresholds with tests performed in real WTMDs showed that the simulator is able to mimic the pacemaker interference. The interference thresholds found in the simulator indicate that pulsed magnetic fields are more likely to cause interference in pacemakers than sinusoidal fields. The security system simulator will help biomedical engineers, manufacturers of medical devices, and manufacturers of security systems to identify incompatible combinations of WTMDs and AIMDs early in the development stage.

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.

The postmodern heart: war veterans' experiences of invasive cardiac technology

BACKGROUND

The consequences of war and medical discourse have historical connections to pacemaker technology. Understanding these consequences is important because war veterans, medicine and cardiac technology have a shared history that continues into the present. The incidence of Australian war veterans needing cardiac pacemakers has increased many-fold in recent years, due to advancing age. This need was recognized by the Australian Department of Veteran Affairs and a cardiac programme was established in the veteran hospital that was the setting for this study.

AIM

This paper reports on a study aimed at capturing the interest and sensitizing the practice of nurses involved in the care of war veterans and other health care consumers who have been diagnosed as requiring a cardiac pacemaker. The study sought to answer the question, 'How does the war veteran experience his body in relation to invasive cardiac technology?'.

METHOD

The research was guided by the principles of interpretive interactionism, and used unstructured interviews with eight male war veterans. The data were collected in 2000.

FINDINGS

Thematic and content analysis revealed five themes: emotional knowing; the medical encounter; belief in the myth of miracle; technological constraint; and the altered heart. The findings indicated that the human dimension was characterized by experiences of ambivalence, inner conflict, powerlessness and suffering.

CONCLUSION

Nursing is at the interface of science and patient care, and this study contributes to nursing knowledge by focusing on a previously unresearched topic, namely embodied interactions between war veterans and invasive cardiac pacemakers. Within a highly technical area such as cardiology, nurses can still work around the technology and keep patients as their primary focus, thus promoting quality care. A humanistic rather than a technological focus locates nurses between patients and cardiac technology. In this in-between location, nurses are not an extension of cardiac technology but a valuable source of information, education, and counselling.

Safety of a combined strength and endurance training using neuromuscular electrical stimulation of thighs muscles in patients with heart failure and bipolar sensing cardiac pacemakers

Neuromuscular electrical stimulation (NMES) is an effective and non-strenuous therapy to enhance the strength and endurance capacity of the skeletal muscles in patients with severe chronic heart failure. NMES in patients with pacemakers is controversial because potential electromagnetic interference may result in pacemaker malfunction. Therefore, such patients are in general excluded from NMES. The aim of this pilot study was to evaluate the safety of a combined NMES protocol to increase strength and endurance capacity of the skeletal muscles in patients with heart failure and implanted pacemakers. Seven patients with chronic heart failure and implanted cardiac pacemakers with bipolar sensing leads received NMES treatment of thigh muscles, using a combined protocol comprising biphasic, symmetric, rectangular constant current impulses at different frequencies (8-50 Hz), pulse width up to 60 s (8 Hz), 4 s (15 Hz), 4 s (30 Hz), and 6 s (50 Hz), and amplitudes up to +/- 100 mA (all frequencies) applied to both knee extensor and flexor muscles via surface electrodes (8 x 13 cm each). Acute electromagnetic interference during a safety procedure (telemetric monitoring) before therapeutic NMES application was not observed in any of the patients. The 7 patients received during 20 therapeutic NMES sessions a total of 23,380 on-phases, comprising 2194.08 x 10(3) biphasic electrical pulses, without adverse events. Heart rate monitoring during stimulation and pacemaker interrogation revealed no abnormalities. NMES treatment of thigh muscles using a combined NMES protocol to enhance strength and endurance capacity appears to be safe in patients with heart failure and implanted pacemakers with bipolar sensing, as far as the described electrode configuration and parameter range is applied.

Do airport metal detectors interfere with implantable pacemakers or cardioverter-defibrillators?

OBJECTIVES

The aim of this study was to determine whether airport metal detector gates (AMDGs) interfere with pacemakers (PMs) or implantable cardioverter-defibrillators (ICDs).

BACKGROUND

It is currently unknown whether AMDGs interfere with implanted PMs or ICDs.

METHODS

A total of 348 consecutive patients (200 PM and 148 ICD recipients) have been tested for the occurrence of electromagnetic interference (EMI) within the electromagnetic field of a worldwide-used airport metal detector.

RESULTS

No interference, such as pacing or sensing abnormalities, was observed in any of the 200 PM and 148 ICD patients; also no reprogramming occurred.

CONCLUSIONS

In vivo testing of PM and ICD systems showed no EMI with a standard AMDG. Clinically relevant interactions with implanted PMs or ICDs seem unlikely.

Pacemakers and store security devices

The ever-increasing complexity of medical device therapy and installation of public electronic security systems demands vigilance in discerning interactions that may be harmful to patients during typical activities of daily living. Premature pacemaker stimulation, isolated skipped beats, or reversion to backup asynchronous pacing have been observed during in vitro and in vivo testing. To date, no deaths and only minor inconvenience have been reported during extreme exposure of patients with pacemakers when they have come directly in contact with or in close apposition to electronic security systems. Patients with any type of implanted electronic medical system should be forewarned: "Don't lean, don't linger" near any potential source of electromagnetic interference. Changing technologies in implantable electronic medical systems as well as societal sources of electromagnetic interference require continued awareness on the part of physicians and patients alike, with care being taken to distinguish largely theoretical hazards from those that constitute meaningful dangers to patients with implanted cardiac arrhythmia devices.