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.

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.

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.

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).

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.

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.

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.

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.

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.

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.

Ophthalmic laser treatments are discouraged in patients with implantable pulse generators (IPGs, pacemakers) and implantable cardioverter defibrillators (ICD) due to potential effects of the electromagnetic interference (EMI) emitted by ophthalmic laser systems. We assessed the effects of EMI generated by ophthalmic laser systems and laser discharge on IPG and ICD function.

Two implantable devices, one Victory dual-chamber IPG (St Jude Medical, Minneapolis, MN, USA) and one Atlas II + dual-chamber ICD (St Jude Medical), were consecutively placed in a simulated thoracic chamber and exposed to three ophthalmic laser systems: the VISX Star S4 Excimer Laser, Lumenis Selecta II 532 neodymium-doped yttrium aluminium garnet (Nd:YAG) laser, and Ellex Ultra Q 1064 nm Nd:YAG laser. For each laser system, the apparatus was placed in the relative position of a patient while common laser procedures were delivered to a plastic object. Device pacing parameters were programmed to the highest possible sensitivity settings. The pacing and defibrillation function of the implantable devices, including electrograms, were continuously monitored. The EMI emitted from ophthalmic lasers did not lead to oversensing, inappropriate therapy, or change in the programming of the implantable cardiac devices. Manufacturing electrical tests performed on both devices showed that the cardiac devices continued to meet all the specifications for proper device function.

The St Jude Medical Victory IPG and Atlas II + ICD were not affected by the EMI emitted by the ophthalmic laser systems.

Electromagnetic fields generated by electrical devices may cause interference with permanent pacemakers. Media players are becoming a common mode of portable entertainment. The most common media players used worldwide are iPods. These devices are often carried in a shirt chest pocket, which may place the devices close to an implanted pacemaker.

The purpose of this study was to determine if iPods cause interference with pacemakers.

In this prospective, single-blinded study, 100 patients who had cardiac pacemakers were tested with four types of iPods to assess for interference. Patients were monitored by a single-channel ECG monitor as well as the respective pacemaker programmer via the telemetry wand. iPods were tested by placing them 2 inches anterior to the pacemaker and wand for up to 10 seconds. To simulate actual use, standard-issue headphones were plugged into the iPods. To maintain consistency, the volume was turned up maximally, and the equalizer was turned off. A subset of 25 patients underwent testing on 2 separate days to assess for reproducibility of interference. Pacemaker interference was categorized as type I or type II telemetry interference. Type I interference was associated with atrial and/or ventricular high rates on rate histograms. Type II interference did not affect pacemaker rate counters. Electromagnetic emissions from the four iPods also were evaluated in a Faraday cage to determine the mechanism of the observed interference.

One hundred patients (63 men and 37 women; mean age 77.1 +/- 7.6 years) with 11 single-chamber pacemakers and 89 dual-chamber pacemakers underwent 800 tests. The incidence of any type of interference was 51% of patients and 20% of tests. Type I interference was seen in 19% of patients and type II in 32% of patients. Reproducibility testing confirmed that interference occurred regardless of pacing configuration (unipolar or bipolar), pacing mode (AAI, VVI, or DDD), and from one day to the next. Electromagnetic emissions testing from the iPods demonstrated maximum emissions in the pacemaker carrier frequency range when the iPod was turned "on" with the headphones attached.

iPods placed within 2 inches of implanted pacemakers monitored via the telemetry wand can cause interference with pacemakers.

In the biomedical literature there are a number of reports that speculate about possible effects in the body due to the demodulation of electromagnetic fields. However, only few interactions in amplitude-modulated or even pulse-modulated electromagnetic waves are fundamentally plausible and have been demonstrated to occur in humans. The following observations fall into this specific category: thermal effects of amplitude- or pulse-modulated microwaves; demodulation of amplitude- or pulse-modulated electromagnetic waves in cell membranes; and demodulation of amplitude- or pulse-modulated electromagnetic fields in the electronics of implants such as cardiac pacemakers or cardioverter defibrillators. The possible consequences of these effects for the organism, their probability of occurrence in everyday life field conditions, and, consequently, the implications for limiting exposure are very different. Microwave hearing is a harmless effect which is perceived by humans only in strong fields with high peak power densities of more than 100 mW cm(-2). In normal residential or occupational environments the peak power density of even the strongest microwave sources is only around 1 mW cm(-2). Demodulation of pulse-modulated electromagnetic fields in the cell membranes decreases the stimulation threshold of nerves and muscles and can introduce numerous adverse effects ranging from perception of pain to dangerous cardiac fibrillations. The stimulation and demodulation effects are restricted to carrier frequencies up to several MHz. In experiments with 900 and 1,800 MHz packets with lengths of up to 100 ms and applied powers of up to 100 W, neither a direct stimulation of superficial nerves and muscles nor the conditioning of an electrical current stimulus could be confirmed. Pulse-modulated electromagnetic waves are demodulated in the electronic circuits of implants and can inhibit cardiac pacemakers and introduce cardiac arrest in this way. The highest sensitivity results from repetition rates of pulses below 100 Hz. The preceding two implications should be considered in the elaboration of new general guidelines limiting the exposure for healthy as well as for sick persons in the future.

This study examined cellular phone ringing interference with automated external defibrillators (AED).

The phone systems tested were two single band handheld telephones: (1) a Global System for Mobile Communication (GSM) receiver; and (2) a Personal Communication Services (PCS) receiver. The ringing phase of a digital cellular phone includes a brief burst of peak-emitted power. The GSM had a maximum power output of 2 W, operating on a 900 MHz carrier frequency, and the PCS had a maximum output of 1 W, operating on a 1800 MHz carrier frequency. During AED monitoring, the digital cellular telephone was placed successively in three positions: (1) on the AED; (2) on the patient's chest between the electrodes; and (3) on the connector between the electrodes and the AED cable. After positioning the cellular phone, calls were placed during the AED analyzing phase.

Three AED models were tested using their original electrodes: (1) LifePak 20 monitor/defibrillator device; (2) Lifepak 20 P monitor/defibrillator/stimulator (Medtronic Emergency Response Systems, Redmond, WA, USA); and (3) HeartStart XL M4735A monitor/defibrillator (Philips Medical Systems, Andover, MA, USA). The first two devices had Quik-Combo electrodes and the third device had Adults Plus multifunction electrodes. Ninety-one tests were performed on 13 patients. The only disturbance provoked by testing was noise emitted by the AED speaker when the receiver was close to the device. The noise began 2-4 s before the first audible ringing tone and persisted throughout the ringing phase. The distance at which this effect could be prevented was 15 cm.

Clinical testing during ECG monitoring by an AED during call from a cellular phone did not show any analysis dysfunction during unshockable rhythms and provoked only transient dysfunction of the speaker device.