Electromagnetic interference with pacemakers caused by portable media players

Assembled one-dimensional nanowires for flexible electronic devices via printing and coating: Techniques, applications, and perspectives

The rapid progress in flexible electronic devices has necessitated continual research into nanomaterials, structural design, and fabrication processes. One-dimensional nanowires, characterized by their distinct structures and exceptional properties, are considered essential components for various flexible electronic devices. Considerable attention has been directed toward the assembly of nanowires, which presents significant advantages. Printing and coating techniques can be used to assemble nanowires in a relatively simple, efficient, and cost-competitive manner and exhibit potential for scale-up production in the foreseeable future. This review aims to provide an overview of nanowire assembly using printing and coating techniques, such as bar coating, spray coating, dip coating, blade coating, 3D printing, and so forth. The application of assembled nanowires in flexible electronic devices is subsequently discussed. Finally, further discussion is presented on the potential and challenges of flexible electronic devices based on assembled nanowires via printing and coating.

Bioimpedance analysis is safe in patients with implanted cardiac electronic devices

BACKGROUND & AIMS

There is an increase in the number of patients worldwide with cardiac implantable electronic devices (CIEDs). Current medical practice guidelines warn against performing bioimpedance analysis (BIA) in this group of patients in order to avoid any electromagnetic interference. These recommendations restrict using the BIA in patients undergoing heart failure or with nutrition disorders in whom BIA could be of major interest in detecting peripheral congestion and to help guide treatment. The present study was conducted to evaluate whether BIA caused electromagnetic interference in patients having CIEDs.

METHODS

Patient enrollment was conducted during routine face-to-face consultations for scheduled CIEDs interrogations. Device battery voltage, lead impedance, pacing thresholds and device electrograms were recorded before and after each BIA measurement to detect any electromagnetic interference or oversensing.

RESULTS

A total of 200 patients were enrolled. During BIA, no significant changes in battery voltage, lead impedance or pacing thresholds were detected, nor were there any inappropriate over- or undersensing observed in intracardiac electrograms. Furthermore, 6- and 12-month follow-up did not reveal any changes in CIEDs.

CONCLUSIONS

This study shows no interference in patients equipped with CIEDs and suggests that BIA can be securely performed in these patients. Trial registered under the identifier NCT03045822.

Asystole detected by implantable loop recorders: true or false?

We report a case of a false asystole detected by an implantable loop recorder a few days after its implantation. In the discussion section we try to give some hints to help cardiac electrophysiologists in distinguish true from false asystoles, in order to avoid unuseful and potentially dangerous implantations of pacemakers.

Safety of capsule endoscopy using human body communication in patients with cardiac devices

BACKGROUND

The MiroCam (IntroMedic, Ltd., Seoul, Korea) is a small-bowel capsule endoscope that uses human body communication to transmit data. The potential interactions between cardiac devices and the capsule endoscope are causes for concern, but no data are available for this matter.

AIM

This clinical study was designed to evaluate the potential influence of the MiroCam capsules on cardiac devices.

METHODS

Patients with cardiac pacemakers or implantable cardiac defibrillators referred for evaluation of small bowel disease were prospectively enrolled in this study. Before capsule endoscopy, a cardiologist checked baseline electrocardiograms and functions of the cardiac devices. Cardiac rhythms were continuously monitored by 24-h telemetry during capsule endoscopy in the hospital. After completion of procedures, functions of the cardiac devices were checked again for interference. Images from the capsule endoscopy were reviewed and analyzed for technical problems.

RESULTS

Six patients, three with pacemakers and three with implantable cardiac defibrillators, were included in the study. We identified no disturbances in the cardiac devices and no arrhythmias detected on telemetry monitoring during capsule endoscopy. No significant changes in the programmed parameters of the cardiac devices were noted after capsule endoscopy. There were no imaging disturbances from the cardiac devices on capsule endoscopy.

CONCLUSIONS

Capsule endoscopy using human body communication to transmit data was safely performed in patients with cardiac pacemakers or implantable cardiac defibrillators. Images from the capsule endoscopy were not affected by cardiac devices. A further large-scale study is required to confirm the safety of capsule endoscopy with various types of cardiac devices.

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.

Arrhythmias in the coronary care unit

Symptomatic sustained cardiac arrhythmias are frequently observed in in the coronary care unit and often lead to hemodynamic compromise, especially in the presence of multisystem disease. The predominant arrhythmias noted in intensive care units are tachyarrhythmias, particularly atrial fibrillation and flutter, and ventricular tachycardia. Bradycardias, arguably less life-threatening than tachyarrhythmias, can arise from sinus node dysfunction or atrioventricular conduction block; transient vagally-mediated bradycardias are frequently encountered as well. Prompt diagnosis of the patient with tachycardia is critical as treatment depends on the accurate diagnosis of tachycardia mechanism. The electrocardiogram remains the most important diagnostic tool for the evaluation of both wide and narrow complex tachycardia. The electrocardiographic diagnosis of wide complex tachycardia is based on evaluation of atrioventricular relationship and QRS morphology while the diagnosis of narrow complex tachycardia is based on the location and morphology of P waves. It is important for critical care specialists to understand the principles of cardiac arrhythmia diagnosis and remain current with the recent advances in the pharmacologic and non-pharmacologic management of patients with arrhythmias.

Do media players cause interference with pacemakers?

BACKGROUND

Electrical devices generate electromagnetic fields that may interfere with pacemakers. Media players cause telemetry interference with pacemakers, but it is not known whether they cause direct interference with pacemakers. The purpose of this study was to examine the interaction between pacemakers and 3 different media players.

METHODS

In this prospective, randomized study, 54 patients with dual chamber pacemakers who were in sinus rhythm underwent baseline observation, followed by observation under telemetry communication. These patients were then randomly evaluated with 3 media players (iPod 3G, iPod Photo, and iPod Touch Apple, Cupertino, CA) with and without telemetry communication for 1 minute each. Patients were monitored for pacemaker malfunction using a single-channel ECG during exposure to media players. The pacemaker was interrogated after each exposure and an interrogation report was printed for evaluation. Pacemaker interference was categorized as type I, II, or III. Types I and II interference described telemetry interference and type III interference was defined as any direct interference with pacemaker function or programmed parameters.

RESULTS

A total of 54 patients (29 men and 25 women; mean age 77.2 +/- 9.3 y) were evaluated. In total, of the 162 tests (for telemetry interference) 36.4% were positive (Type I and II). Type III interference was also evaluated in 162 tests and none showed any evidence of direct interference.

CONCLUSION

Media players cause telemetry interference with pacemakers, but they do not directly interfere with pacemaker function.

A media player causes clinically significant telemetry interference with implantable loop recorders

BACKGROUND

The implantable loop recorder is a useful diagnostic tool for intermittent cardiovascular symptoms because it can automatically record arrhythmias as well as a patient-triggered ECG. Media players have been shown to cause telemetry interference with pacemakers. Telemetry interference may be important in patients with implantable loop recorders because capturing a patient-triggered ECG requires a telemetry link between a hand-held activator and the implanted device. The purpose of this study was to determine if a media player causes interference with implantable loop recorders.

METHODS

Fourteen patients with implantable loop recorders underwent evaluation for interference with a 15 GB third generation iPod (Apple, Inc.) media player. All patients had the Reveal Plus (Medtronic, Inc.) implantable loop recorder. We tested for telemetry interference on the programmer by first establishing a telemetry link with the loop recorder and then, the media player was placed next to it, first turned off and then, on. We evaluated for telemetry interference between the activator and the implanted device by placing the activator over the device (normal use) and the media player next to it, first turned off and then, on. We made 5 attempts to capture a patient-triggered ECG by depressing the activator switch 5 times while the media player was off or on.

RESULTS

Telemetry interference on the programmer screen, consisting of either high frequency spikes or blanking of the ECG channel was seen in all patients. Telemetry interference with the activator resulted in failure to capture an event in 7 patients. In one of these patients, a green indicator light on the activator suggested that a patient-triggered event was captured, but loop recorder interrogation did not show a captured event. In the remaining 7 patients, an event was captured and appropriately recognized by the device at least 1 out of 5 times.

CONCLUSION

A media player playing in close proximity to an implanted loop recorder may interfere with capture of a patient-triggered event. Patients should be advised to keep media players away from their implanted loop recorder.

Digital music players cause interference with interrogation telemetry for pacemakers and implantable cardioverter-defibrillators without affecting device function

BACKGROUND

Concern exists regarding the potential electromagnetic interaction between pacemakers, implantable cardioverter-defibrillators (ICDs) and digital music players (DMPs). A preliminary study reported interference in 50% of patients whose devices were interrogated near Apple iPods.

OBJECTIVE

Given the high prevalence of DMP use among young patients, we sought to define the nature of interference from iPods and evaluate other DMPs.

METHODS

Four DMPs (Apple Nano, Apple Video, SanDisk Sansa and Microsoft Zune) were evaluated against pacemakers and ICDs (PM/ICD). Along with continuous monitoring, we recorded a baseline ECG strip, sensing parameters and lead impedance at baseline and for each device.

RESULTS

Among 51 patients evaluated (age 6 to 60 years, median 22), there was no interference with intrinsic device function. Interference with the programmer occurred in 41% of the patients. All four DMPs caused programmer interference, including disabled communication between the PM/ICD and programmer, noise in the ECG channel, and lost marker channel indicators. Sensing parameters and lead impedances exhibited no more than baseline variability. When the DMPs were removed six inches, there were no further programmer telemetry interactions.

CONCLUSIONS

Contrary to a prior report, we did not identify any evidence for electromagnetic interference between a selection of DMPs and intrinsic function of PM/ICDs. The DMPs did sometimes interfere with device-programmer communication, but not in a way that compromised device function. Therefore, we recommend that DMPs not be used during device interrogation, but suggest that there is reassuring counterevidence to mitigate the current high level of concern for interactions between DMPs and implantable cardiac rhythm devices.