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

Hearts in the sky: understanding the cardiovascular implications of air travel

Air travel is widely regarded as the safest mode of transportation, with the United States leading in airline passengers. However, travelers with pre-existing heart conditions face acute cardiovascular risks. Flight pilots and cabin crew are particularly vulnerable to air travel's physiological changes, which can significantly impair their health and performance. Cabin pressure differences and reduced oxygen levels at cruising altitudes of 5000-8000 feet make air travel challenging for individuals with underlying cardiac and pulmonary problems. This, along with dry air, sleep deprivation, missed medication and prolonged sitting, can lead to physiological changes. In-flight and pre-flight stressors contribute to increased health issues, and studies show a rise in medical emergencies during flights. Prolonged exposure to the airplane environment can lead to various health issues for pilots and cabin crew. These changes include impaired judgment, cognitive function and discomfort in the sinuses and ears due to pressure differentials. Therefore, thorough medical screening, skilled instrument use and compliance with safety measures are essential to mitigate these risks. This article reviews the cardiac implications of air travel, discussing the underlying pathophysiology, associated risks and preventive measures to ensure safer flights for individuals with cardiovascular diseases.

[Electromagnetic interference : Pacemakers, cardiac resynchronization therapy devices, implantable cardioverter-defibrillator]

Patients with cardiac pacemakers, implantable cardioverter-defibrillators (ICDs), and cardiac resynchronization therapy devices (CRT) are exposed to different types of electromagnetic interference (EMI) at home and at work. Due to the constantly increasing role of electrically active appliances in daily use and the introduction of new therapy concepts such as the leadless cardiac pacemaker and the subcutaneous defibrillator, this topic is of great relevance. The further development of the implanted devices and the almost complete use of bipolar leads has reduced the overall risk of EMI. This review article provides information about the current status of possible interference in the private environment and how to avoid it. In addition, information is provided on how to deal with occupational sources of interference.

Travelling with heart failure: risk assessment and practical recommendations

Patients with heart failure are at a higher risk of cardiovascular events compared with the general population, particularly during domestic or international travel. Patients with heart failure should adhere to specific recommendations during travel to lower their risk of developing heart failure symptoms. In this Review, we aim to provide clinicians with a set of guidelines for patients with heart failure embarking on national or international travel. Considerations when choosing a travel destination include travel distance and time, the season upon arrival, air pollution levels, jet lag and altitude level because all these factors can increase the risk of symptom development in patients with heart failure. In particular, volume depletion is of major concern while travelling given that it can contribute to worsening heart failure symptoms. Pre-travel risk assessment should be performed by a clinician 4-6 weeks before departure, and patients should receive advice on potential travel-related illness and on strategies to prevent volume depletion. Oxygen supplementation might be useful for patients who are very symptomatic. Upon arrival at the destination, potential drug-induced photosensitivity (particularly in tropical destinations) and risks associated with the local cuisine require consideration. Special recommendations are needed for patients with cardiac implantable electronic devices or left ventricular assist devices as well as for those who have undergone major cardiac surgery.

Is air travel safe for patients with cardiac implantable electronic devices?

Parallel to the rapid expansion of air travel services and advances in medical technology, more passengers with cardiac implantable electronic devices (CIEDs) fly each year. In general, commercial airline flights are considered safe for patients with CIEDs; nevertheless, some specific precautions should be undertaken in some certain circumstances. Apart from the risk of a minor and overlooked pneumothorax early after implantation of a CIED, which may be aggravated due to sudden pressure changes during flight, electromagnetic interference, cosmic radiation and vibration are the other risks a patient with a CIED may encounter during air travel, nevertheless, these are rare and often do not bring about significant clinical consequences.

Commercial Air Travel for Passengers With Cardiovascular Disease: Recommendations for Common Conditions

The exponential growth of commercial flights has resulted in an explosion of air travelers over the last few decades, including passengers with a wide range of cardiovascular conditions. Notwithstanding the ongoing COVID-19 pandemic that had set back the aviation industry for the next 1-2 years, air travel is expected to rebound fully by 2024. Guidelines and evidence-based recommendations for safe air travel in this group vary, and physicians often encounter situations where opinions and assessments on fitness for flights are sought. This article aims to provide an updated suite of recommendations for the aeromedical disposition of passenger with common cardiovascular conditions, such as ischemic heart disease, congestive heart failure, valvular heart disease, cardiomyopathies, and common arrhythmias.

Commercial Air Travel for Passengers With Cardiovascular Disease: Stressors of Flight and Aeromedical Impact

The exponential growth of commercial flights has resulted in a sharp rise of air travellers over the last 2 decades, including passengers with a wide range of cardiovascular conditions. Notwithstanding the ongoing COVID-19 pandemic that had set back the aviation industry for the next 1 to 2 years, air travel is expected to rebound fully by 2023-2024. Guidelines and evidence-based recommendations for safe air travel in this group vary, and physicians often encounter situations where opinions and assessments on fitness for flights are sought. This article aims to provide an overview of the stressors of commercial passenger flights with an impact on cardiovascular health for the general cardiologist and family practitioner, when assessing the suitability of such patients for flying fitness.

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.

Security millimetre wave body scanner safe for patients with leadless pacemakers or subcutaneous implantable cardioverter-defibrillators

PURPOSE

This study was designed to evaluate the electromagnetic interference (EMI) effects and safety of the new security screening millimetre wave body scanners (MWBSs) for patients with rare cardiac implantable electronic devices (CIEDs).

METHODS

We identified 73 patients with either entirely subcutaneous implantable cardioverter-defibrillators (S-ICD) or leadless pacemakers (LPM) attending routine device follow-up. CIED programming was optimised for the detection of EMI occurrence, and high-voltage therapy was disabled. Patients then underwent millimetre wave body scans under continuous ECG monitoring. Scanning was performed at the recommended distance as well as in close proximity to the scanner emulating accidental exposure. CIED function was observed for EMI effects.

RESULTS

There were no episodes of inhibition of pacing in the leadless pacemaker subgroup, no oversensing in the S-ICD subgroup and no spontaneous device reprogramming in any group. There was no change in pacing or sensing thresholds, and S-ICD vector eligibility remained unchanged after scanning with the MWBS. No CIEDs were identified by the MWBS during the study.

CONCLUSION

No EMI events were detected during the use of MWBSs by patients with either S-ICDs or LPMs. This data should be reassuring for patients suggesting that they can undergo security body scans without worries or disclosure of their CIED status.

Experiences and Attitudes of International Travelers with Cardiovascular Disease: A Qualitative Analysis

Cardiovascular disease (CVD) is the leading cause of death among international travelers. It is unknown whether CVD is a barrier to international travel. The purpose of this study was to describe the travel experiences of a cohort of individuals with CVD, to identify their perceived barriers to travel, and to generate recommendations for CVD travelers, medical practitioners, and the travel industry. Semi-structured interviews were conducted with CVD patients who had attended either a regional, structured, multidisciplinary CVD prevention program or a cardiac rehabilitation program. Coding and thematic analysis of the transcripts were supported by NVivo® computer software. Peer debriefing with an independent researcher was undertaken. Demographic and clinical data such as gender, age, and types of cardiovascular condition were also recorded. Twelve patients (eight males), with a mean age of 68 ± 7.58 years, agreed to semi-structured interviews (26-78 minutes duration). The key themes emerging from the interviews included altered travel perception, accessing medical care overseas, issues with medications, medical device concerns at airports, restricted leisure travel activities, and optimal self-care. All interviewees perceived a health benefit to travel and did not regard CVD as a significant barrier to international travel. Certain cardiovascular conditions precipitated more travel anxiety. These findings highlight the unique experiences of CVD patients when engaging in international travel. Cardiovascular disease optimization and responsible travel health behaviors would facilitate medically uneventful overseas travel. The results may inform pretravel health advice given to CVD travelers. Further studies on issues relating to air travel in CVD are warranted.

Patients with pacemakers or defibrillators do not need to worry about e-Cars: An observational study

BACKGROUND

Electric cars are increasingly used for public and private transportation and represent possible sources of electromagnetic interference (EMI). Potential implications for patients with cardiac implantable electronic devices (CIED) range from unnecessary driving restrictions to life-threatening device malfunction. This prospective, cross-sectional study was designed to assess the EMI risk of electric cars on CIED function.

METHODS

One hundred and eight consecutive patients with CIEDs presenting for routine follow-up between May 2014 and January 2015 were enrolled in the study. The participants were exposed to electromagnetic fields generated by the four most common electric cars (Nissan Leaf, Tesla Model S, BMW i3, VW eUp) while roller-bench test-driving at Institute of Automotive Technology, Department of Mechanical Engineering, Technical University, Munich. The primary endpoint was any abnormalities in CIED function (e.g. oversensing with pacing-inhibition, inappropriate therapy or mode-switching) while driving or charging electric cars as assessed by electrocardiographic recordings and device interrogation.

RESULTS

No change in device function or programming was seen in this cohort which is representative of contemporary CIED devices. The largest electromagnetic field detected was along the charging cable during high current charging (116.5 μT). The field strength in the cabin was lower (2.1-3.6 μT).

CONCLUSIONS

Electric cars produce electromagnetic fields; however, they did not affect CIED function or programming in our cohort. Driving and charging of electric cars is likely safe for patients with CIEDs.

[Travelling with a pacemaker or implanted defibrillator]

There are no guidelines for patients travelling with implanted pacemakers or defibrillators. Only few publications deal with specific problems that this patient group might face. In this article different aspects of travelling with implanted electric devices are summarized. Patients with pacemakers and implanted defibrillators have nearly no limits when travelling. An exception to that rule is scuba diving, which mostly is limited because of the device. In general it is the underlying heart disease or arrhythmia that limits patients' travel activities. It is reasonable to travel after implantation only after wound healing is complete because arm movement on the implant site is limited and the risk of wound infection and lead dislocation is elevated in the early phase. However, if necessary, flying is possible 2 days after an uncomplicated implantation if pneumothorax can be excluded. Security checks can be passed safely by patients with pacemakers/defibrillators. Only repetitive movement of a handheld metal detector over the device should be avoided. When travelling to different time zones it might be reasonable to deactivate a programmed sleep rate (Medtronic, Biotronik). Patients at risk for ventricular arrhythmia (mainly patients with an implantable cardioverter-defibrillator) must make sure to take all possible preventive measures to avoid travelers' diarrhea. In case of infection early replacement of fluids and electrolytes is essential.

Navigating air travel and cardiovascular concerns: Is the sky the limit?

As the population ages and our ability to care for patients with cardiac disease improves, an increasing number of passengers with cardiovascular conditions will be traveling long distances. Many have had cardiac symptoms, recent interventions, devices, or surgery. Air travel is safe for most individuals with stable cardiovascular disease. However, a thorough understanding of the physiologic changes during air travel is essential given the potential impact on cardiovascular health and the risk of complications in passengers with preexisting cardiac conditions. It is important for clinicians to be aware of the current recommendations and precautions that need to be taken before and during air travel for passengers with cardiovascular concerns.

Personal medical electronic devices and walk-through metal detector security systems: assessing electromagnetic interference effects

Background

There have been concerns that Electromagnetic security systems such as walk-through metal detectors (WTMDs) can potentially cause electromagnetic interference (EMI) in certain active medical devices including implantable cardiac pacemakers and implantable neurostimulators. Incidents of EMI between WTMDs and active medical devices also known as personal medical electronic devices (PMED) continue to be reported. This paper reports on emission measurements of sample WTMDs and testing of 20 PMEDs in a WTMD simulation system.

Methods

Magnetic fields from sample WTMD systems were characterized for emissions and exposure of certain PMEDs. A WTMD simulator system designed and evaluated by FDA in previous studies was used to mimic the PMED exposures to the waveform from sample WTMDs. The simulation system allows for controlled PMED exposure enabling careful study with adjustable magnetic field strengths and exposure duration, and provides flexibility for PMED exposure at elevated levels in order to study EMI effects on the PMED. The PMED samples consisted of six implantable cardiac pacemakers, six implantable cardioverter defibrillators (ICD), five implantable neurostimulators, and three insulin pumps. Each PMED was exposed in the simulator to the sample WTMD waveforms using methods based on appropriate consensus test standards for each of the device type.

Results

Testing the sample PMEDs using the WTMD simulator revealed EMI effects on two implantable pacemakers and one implantable neurostimulator for exposure field strength comparable to actual WTMD field strength. The observed effects were transient and the PMEDs returned to pre-exposure operation within a few seconds after removal from the simulated WTMD exposure fields. No EMI was observed for the sample ICDs or insulin pumps.

Conclusion

The findings are consistent with earlier studies where certain sample PMEDs exhibited EMI effects. Clinical implications were not addressed in this study. Additional studies are needed to evaluate potential PMED EMI susceptibilities over a broader range of security systems.

Prevention of Medical Events During Air Travel: A Narrative Review

Prior to traveling, and when seeking medical pretravel advice, patients consult their personal physicians. Inflight medical issues are estimated to occur up to 350 times per day worldwide (1/14,000-40,000 passengers). Specific characteristics of the air cabin environment are associated with hypoxia and the expansion of trapped gases into body cavities, which can lead to harm. The most frequent medical events during air travel include abdominal pain; ear, nose, and throat pathologies; psychiatric disorders; and life-threatening events such as acute respiratory failure or cardiac arrest. Physicians need to be aware of the management of these conditions in this unusual setting. Chronic respiratory and cardiovascular diseases are common and are at increased risk of acute exacerbation. Physicians must be trained in these conditions and inform their patients about their prevention.

Air travel considerations for the patients with heart failure

Context:

Prevalence of patients with heart failure (HF) is increasing in worldwide, and also the number of people with HF traveling long distances is increasing. These patients are more prone to experience problems contributed air travel and needs more attention during flight. However, observational studies about problems of HF patients during flight and appropriated considerations for them are limited.

Evidence Acquisition:

We evaluated the conditions that may be encountered in a HF patient and provide the recommendations to prevent the exacerbation of cardiac failure during air travel. For this review article, a comprehensive search was undertaken for the studies that evaluated the complications and considerations of HF patients during flight. Data bases searched were: MEDLINE, EMBASE, Science Direct, and Google Scholar.

Results:

HF patients are more prone to experience respiratory distress, anxiety, stress, cardiac decompensation, and venous thromboembolism (VTE) during air travel. Although stable HF patients can tolerate air travel, but those with acute heart failure syndrome should not fly until complete improvement is achieved.

Conclusions:

Thus, identifying the HF patients before the flight and providing them proper education about the events that may occur during flight is necessary.

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.

In vitro assessment of the immunity of implantable cardioverter-defibrillators to magnetic fields of 50/60 Hz

Public concern for the compatibility of electromagnetic (EM) sources with active implantable medical devices (AIMD) has prompted the development of new systems that can perform accurate exposure studies. EM field interference with active cardiac implants (e.g. implantable cardioverter-defibrillators (ICDs)) can be critical. This paper describes a magnetic field (MF) exposure system and the method developed for testing the immunity of ICD to continuous-wave MFs. The MFs were created by Helmholtz coils, housed in a Faraday cage. The coils were able to produce highly uniform MFs up to 4000 µT at 50 Hz and 3900 µT at 60 Hz, within the test space. Four ICDs were tested. No dysfunctions were found in the generated MFs. These results confirm that the tested ICDs were immune to low frequency MFs.

Implanted cardiac devices are reliably detected by commercially available metal detectors

OBJECTIVE

Explosions of Cardiovascular Implantable Electronic Devices (CIEDs) (pacemakers, defibrillators, and loop recorders) are a well-recognized problem during cremation, due to lithium-iodine batteries. In addition, burial of the deceased with a CIED can present a potential risk for environmental contamination. Therefore, detection of CIEDs in the deceased would be of value. This study evaluated a commercially available metal detector for detecting CIEDs.

DESIGN

Observational study including pacemaker patients (n = 70) and a control group without pacemaker (n = 95). The investigational device was a hand-held metal detector for detecting metal or electricity wiring.

RESULTS

The metal detector detected the pacemaker in all pacemaker patients and thus exhibited a sensitivity of 100%. The specificity of the metal detector was 86%, and the negative predictive value was 100%. Thirteen individuals without pacemakers were falsely identified as having an implanted device due to implanted prosthetic material or elements of clothing.

CONCLUSION

A simple hand-held metal detector may detect CIEDs with a high sensitivity. It may be of value in detecting CIEDs in deceased persons before burial or cremation. Any signal detected by the metal detector should prompt further investigation of the body and patient files.

Capsule Endoscopy in Patients with Implantable Electromedical Devices is Safe

Background and Study Aims. The presence of an implantable electromechanical cardiac device (IED) has long been considered a relative contraindication to the performance of video capsule endoscopy (CE). The primary aim of this study was to evaluate the safety of CE in patients with IEDs. A secondary purpose was to determine whether IEDs have any impact on images captured by CE. Patients and Methods. A retrospective chart review of all patients who had a capsule endoscopy at Mayo Clinic in Scottsdale, AZ, USA, or Rochester, MN, USA, (January 2002 to June 2010) was performed to identify CE studies done on patients with IEDs. One hundred and eighteen capsule studies performed in 108 patients with IEDs were identified and reviewed for demographic data, method of preparation, and study data. Results. The most common indications for CE were obscure gastrointestinal bleeding (77%), anemia (14%), abdominal pain (5%), celiac disease (2%), diarrhea (1%), and Crohn's disease (1%). Postprocedure assessments did not reveal any detectable alteration on the function of the IED. One patient with an ICD had a 25-minute loss of capsule imaging due to recorder defect. Two patients with LVADs had interference with capsule image acquisition. Conclusions. CE did not interfere with IED function, including PM, ICD, and/or LVAD and thus appears safe. Additionally, PM and ICD do not appear to interfere with image acquisition but LVAD may interfere with capsule images and require that capsule leads be positioned as far away as possible from the IED to assure reliable image acquisition.

Interference of low frequency magnetic fields with implantable cardioverter-defibrillators

OBJECTIVES

The aim of this study was to find the electromagnetic interference (EMI) thresholds for several commonly used implantable cardioverter-defibrillators (ICD).

DESIGN

Seventeen ICDs were exposed to magnetic fields with different intensities produced by the Helmholtz coil system. Sinusoidal, pulse, ramp, and square-waveforms with a frequency range of 2 Hz to 1 kHz were used.

RESULTS

ICD malfunctions occurred in 11 of the 17 ICDs tested. The ICD malfunctions that occurred were false detections of ventricular tachycardia (6/17 ICDs) and ventricular fibrillation (3/17 ICDs), false detection of atrial tachycardia (4/6 dual chamber ICDs) and tachycardia sensing occurring during atrial or ventricular refractory periods (1/17 ICD). In most cases, no interference occurred at magnetic field levels below the occupational safety limits of the International Commission on Non-Ionizing Radiation Protection (ICNIRP). Nevertheless, some frequencies using sine, ramp or square waveforms did interfere with certain ICDs at levels below these limits. No EMI occurred with any of the ICDs below the ICNIRP limits for public exposure.

CONCLUSION

Evaluation of EMI should be part of the risk assessment of an employee returning to work after an ICD implantation. The risk assessment should consider magnetic field intensities, frequencies and waveforms.

Electromagnetic interference and implanted cardiac devices: the nonmedical environment (part I)

The number of patients with cardiovascular implantable electronic devices (CIEDs), such as permanent pacemakers and implantable cardioverter-defibrillators, is dramatically rising due to an aging population and recent clinical trials showing benefits in mortality and morbidity. Coupled with this increase in the number of patients with CIEDs is the proliferation of technology that emits electromagnetic signals, which can potentially interfere with CIED function through electromagnetic interference (EMI). Despite continuous efforts of manufacturers to create "EMI-proof" CIEDs, adverse events from EMI still occur. Physicians caring for patients with CIEDs should be aware of potential sources of EMI and appropriate management options. This 2-part review aims to provide a contemporary overview of the current knowledge regarding risks attributable to EMI interactions from the most common nonmedical (Part I) and medical (Part II) sources.

Small bowel capsule endoscopy in patients with cardiac pacemakers and implantable cardioverter defibrillators: Outcome analysis using telemetry review

AIM: To determine if there were any interactions between cardiac devices and small bowel capsules secondary to electromagnetic interference (EMI) in patients who have undergone small bowel capsule endoscopy (SBCE).

METHODS: Authors conducted a chart review of 20 patients with a cardiac pacemaker (CP) or implantable cardioverter defibrillator (ICD) who underwent continuous electrocardiographic monitoring during their SBCE from 2003-2008. authors searched for unexplained electrocardiogram (ECG) findings, changes in CP and ICD set parameters, any abnormality in transmitted capsule data, and adverse clinical events.

RESULTS: There were no adverse events or hemodynamically significant arrhythmias reported. CP and ICD set parameters were preserved. The majority of ECG abnormalities were also found in pre- or post- SBCE ECG tracings and the CP behavior during arrhythmias appeared appropriate. Two patients seemed to have episodes of undersensing by the CP. However, similar findings were documented in ECGs taken outside the time frame of the SBCE. One patient was observed to have a low signal encountered from the capsule resulting in lack of localization, but no images were lost.

CONCLUSION: Capsule-induced EMI remains a possibility but is unlikely to be clinically important. CP-induced interference of SBCE is also possible, but is infrequent and does not result in loss of images transmitted by the capsule.

Risk assessment of electromagnetic fields exposure with metallic orthopedic implants: a cadaveric study

Metallic materials are well known to strongly interact with electromagnetic fields. While biological effects of such field have been extensively studied, only few works dealt with the interactions of electromagnetic waves with passive metallic device implanted in biological system. Hence only several numerical and phantom simulation studies were focusing on this aspect, whereas no in situ anatomic experiment has been previously performed. In this study the effect of electromagnetic waves on eight different orthopaedic medical devices (six plates from 55 to 318mm length, a total knee and a total hip prosthesis) were explored on six human cadavers. To mimic a random environmental exposure resulting from the most common frequencies band used in domestic environment and medical applications (TV and radio broadcasting, cell phone communication, MRI, diathermy treatment), a multifrequency generator emitting in VHF, UHF, GSM and GCS frequency bands was used. The different medical devices were exposed to an electromagnetic field at 50W/m(2) and 100W/m(2). After 6min exposure, the temperature was measured on three points close to each medical device, and the induced currents were estimated. No significant temperature increase (<0.2°C) was finally detected; beside, a slight induced tension (up to 1.1V) was recorded but would appear too low to induce any biological side effect.

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.

Pacemaker patients' perception of unsafe activities: a survey

BACKGROUND

Cardiac pacing is a recognized and widely used treatment for patients presenting with bradycardia. Physicians expect patients to return to normal activities almost immediately post implantation. However, patients themselves may perceive interference to pacemaker function by various routine activities and devices, and hence continue to lead restricted, disabled lives. The aim of this study is to determine if routine activities are perceived by pacemaker patients to interfere with their device function.

METHODS

A descriptive cross sectional survey was carried out on consecutive patients at the pacemaker clinic at a public hospital in Karachi, Pakistan. A 47-question tool was developed and tested. Patients' perceptions of safety of performing various routine activities, along with socio-demographic data were recorded.

RESULTS

The final sample included 93 adult patients (45% males). 41% were illiterate. 77.4% recalled receiving counselling at implantation, predominantly from the implanting physician and house staff. A considerable proportion of patients considered many routine activities unsafe including driving automobiles (28%), passing through metal detectors (31%), bending over (37%), and sleeping on the side of the pacemaker (30%). Also considered unsafe were operation of household appliances--TV/VCR (television/video cassette recorders) (53%), irons (55%)) and electrical wall switches (56%). For nearly all variables neither literacy nor history of counselling improved incorrect perceptions.

CONCLUSION

This study shows that our pacemaker patients perceive many routine activities as unsafe, potentially leading to disabling life style modifications. The tremendous investment in pacemaker technology to improve patient performance is not going to pay dividends if patients continue to remain disabled due to incorrect perceptions. Further studies are required to determine the reasons for these misperceptions, and to determine if these problems also exist in, and hinder, other patient populations.

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 behavior of dual-chamber pacemakers exposed to a conducted low-frequency disruptive signal

This paper presents a study of the behavior of dual-chamber cardiac pacemakers submitted to low-frequency conducted disruptions. The disruptive signal is sinusoidal, operating at 50 Hz, 60 Hz, 10 kHz and 25 kHz. The behavior of the pacemakers is described by statistical data obtained with a telemetry system and by visualization of the pacemaker signal during the application of the interfering signal. The pacemakers were tested in two configurations. The first one consists of direct application of the interfering signal between the pacemaker terminals. In the second, these attempts are completed by in vitro tests using an electromagnetic model which allow us to take into account the interface which constitutes the human body. The pacemaker under test is inserted into a gelatine phantom mimicking the electrical conductivity of tissues. This study allowed us to define the pacemaker detection thresholds for the two test configurations. For the in vitro approach, which constitutes a complementary approach to a realistic implantation situation, oversensing is noticed for 10 kHz and 25 kHz interfering signal frequencies. Detection thresholds vary from a few tens to a few hundreds of mV, depending on the interfering signal frequency, the device and its programmed detection sensitivities.

Diagnostic uses of metal detectors: a review

Metal detectors have been used for diagnostic purposes since 1881. They have been utilised to localise a myriad of foreign objects including bullets, intraocular metallic fragments, swallowed coins and other foreign bodies and medical devices. Rapid detection of metallic objects may facilitate diagnosis or treatment. Metal detectors are diagnostically useful because of their low expense, lack of radiation exposure and ease of use. This article reviews the history of metal detection in the practice of medicine and provides an overview of the utility of metal detectors in current diagnostic practice.

Safety of wireless capsule endoscopy in patients with implantable cardiac defibrillators

OBJECTIVES

Wireless video capsule endoscopy (CE) is a new technology that allows visualization of the entire small intestinal mucosa. It is indicated for the evaluation of obscure gastrointestinal bleeding (OGIB) and other disorders of the small intestine. Studies to date suggest that CE is safe and associated with few adverse events. A concern, which has not been studied, is the potential effect of CE on implanted cardiac devices such as implantable cardiac defibrillators (ICD) and other electromedical devices. We previously found CE to be safe in patients with cardiac pacemakers. The primary aim of this study was to evaluate the safety of CE in patients with ICDs who were being evaluated for OGIB. In addition, a secondary aim of the study was to determine whether ICDs had any effect on the images captured by CE.

METHODS

Patients referred for the evaluation of OGIB and who also had an ICD were enrolled into the study after informed consent. Five consecutive patients (four females and one male; mean age: 72 yr; range: 60-81 yr) with ICDs were studied. All patients had transvenous endocardial ICDs located in the chest. Prior to CE, patients had a baseline electrocardiogram (ECG) and ICD interrogation. Thereafter, CE was performed in a hospital setting with telemetry monitoring performed simultaneously. A post-procedure ICD interrogation was carried out to evaluate changes in programmed parameters. A cardiologist and ICD nurse specialist together reviewed both the telemetry monitor and the post-procedure ICD interrogation on each patient. When CE studies were reviewed, observations pertaining to technical difficulties and interference with video imaging were documented.

RESULTS

No arrhythmia or other adverse cardiac events were noted during capsule transmission. No interference by the ICD on the CE video images was seen.

CONCLUSIONS

CE was performed safely in these five patients with ICDs, and was not associated with any adverse cardiac events. ICDs also do not appear to interfere with video capsule imaging.

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.

Incidence of Antitachycardia Therapy Suspension Due to Magnet Reversion in Implantable Cardioverter Defibrillators

Electromagnetic interference may result in transient or persistent suspension of antitachycardia therapies in ICDs. The incidence of such events has not been assessed so far. Patient charts were retrospectively analyzed for the occurrence of temporary suspension of antitachycardia therapies as it is stored in the Holter of St. Jude Medical or Ventritex ICDs. Follow-up data of 46 patients and 83.7-patient years were analyzed. Overall, 43 episodes of transient ICD inactivation occurred. Twenty-two of these episodes were related to intentional ICD inactivation in the emergency room or during surgery and 12 episodes were related to ICD follow-up. In nine episodes an environmental source of electromagnetic interference is presumed. None of the interactions resulted in persistent ICD inactivation or reprogramming of the devices. The risk for temporary suspension of ICD therapies unrelated to surgery, intentional magnet application in the emergency room, or routine follow-up is 11% per patient and year. Evaluation of its potential sources and the prevalence of ICD inhibition is warranted.