Telemetry Interference Research Articles

Electromagnetic interference from left ventricular assist device in patients with transvenous implantable cardioverter-defibrillator.

Many advanced heart failure patients have both a left ventricular assist device (LVAD) and an implantable cardioverter-defibrillator (ICD). This study examines incidence, clinical impact, and management of LVAD-related EMI. We performed a three-center retrospective analysis of transvenous ICD implanted patients with LVAD implanted between January 1, 2005 and December 31, 2020. The primary outcome was EMI after LVAD implantation, categorized as LVAD-related noise or telemetry interference. The rate of LVAD-related EMI among the 737 patients (mean age 58.6 ± 12.8 years) studied was 5.0%. Telemetry interference (1.5%) compromised ICD interrogation in all patients. This was resolved successfully with use of a metal shield, encased wand, radiofrequency tower, different ICD programmer or by increasing distance between ICD programmer and LVAD (n=6). ICD replacement was required to reestablish successful communication in three patients. LVAD-related noise (3.5%) led to oversensing (n=4), inappropriate mode switches (n=4), noise reversion (n=3), inhibition of pacing (n=2), inappropriate detection as atrial fibrillation (AF) (n=2) and inappropriate detection as ventricular tachycardia (VT) and/or ventricular fibrillation (VF) (n=2). This noise interference persisted (n=3), resolved spontaneously (n=16), resolved with programming change (n=6) or required lead revision (n=1). EMI from LVAD impacts ICD function, although, the incidence rate is low. Physicians implanting both, LVAD in patients with ICD (more common) or ICD in patients with LVAD, should be aware of possible interferences. Telemetry failure not resolved by metal shielding was overcome by ICD generator replacement to a different manufacturer. In most cases, LVAD-related noise resolves spontaneously.

P5421Prevalence of electromagnetic interference from left ventricular assist devices in patients with implantable cardioverter defibrillator/pacemakers

Abstract Background Many patients eligible for left ventricular assist device (LVAD) therapy already have an implantable cardioverter defibrillator (ICD) and/or pacemaker (PM). However, electromagnetic interference (EMI) between the LVAD and ICD/PM devices could be cumbersome. Purpose The aim of this study was to investigate the prevalence of EMI between different types of ICD/PM in patients implanted with an LVAD. Methods Data was obtained through a retrospective electronic patient database analysis of all LVAD patients (including HeartMate II (HMII) and HeartMate 3 (HM3)), from our tertiary referral center, from December 2006 to February 2019. Device switches have also been taken into account due to elective replacement. Electromagnetic interference was defined as ICD/PM telemetry interference (i.e. the inability to interrogate ICD/PM) Results In total, 109 patients received an LVAD (mean age 52±12, 83% male), Of these, 86 (79%) patients had an ICD/PM at LVAD implantation. One patient with ICD/PM was excluded from further analysis because of missing follow-up data. Among the 85 patients (45 HM II and 40 HM3), 11 (13%) experienced EMI; 5 (11%) with a HM II and 6 (15%) with a HM3 (p=0.59). The implanted ICD/PM devices were from Medtronic (n=25), Abbott (n=23), Biotronik (n=18), Boston Scientific (n=18), and Microport (n=1). EMI with the HM II was present in St Jude/Abbott devices (type 1 Atlas, 1 Unify, 1 Fortify, and 2 Promote). In HM 3 LVAD patients, EMI was observed in Biotronik devices (1 Lumax, 1 Ilivia, 1 Ilesto, and 2 Iperia) and Medtronic (Claria). Conclusion In our cohort of HM II and HM 3 LVAD patients, at least one in seven patients experienced EMI from either the HM II or HM3 LVAD with the ICD/PM. Electromagnetic interference from HM II LVADs was mainly present in patients with St Jude/Abbott ICD/PM devices However, in the HM3 patients, EMI was mainly present in patients with Biotronik devices, which is not yet widely known!

Dual responsive neurostimulation implants for epilepsy.

Closed-loop brain-responsive neurostimulation via the RNS System is a treatment option for adults with medically refractory focal epilepsy. Using a novel technique, 2 RNS Systems (2 neurostimulators and 4 leads) were successfully implanted in a single patient with bilateral parietal epileptogenic zones. In patients with multiple epileptogenic zones, this technique allows for additional treatment options. Implantation can be done successfully, without telemetry interference, using proper surgical planning and neurostimulator positioning.Trajectories for the depth leads were planned using neuronavigation with CT and MR imaging. Stereotactic frames were used for coordinate targeting. Each neurostimulator was positioned with maximal spacing to avoid telemetry interference while minimizing patient discomfort. A separate J-shaped incision was used for each neurostimulator to allow for compartmentalization in case of infection. In order to minimize surgical time and risk of infection, the neurostimulators were implanted in 2 separate surgeries, approximately 3 weeks apart.The neurostimulators and leads were successfully implanted without adverse surgical outcomes. The patient recovered uneventfully, and the early therapy settings over several months resulted in preliminary decreases in aura and seizure frequency. Stimulation by one of the neurostimulators did not result in stimulation artifacts detected by the contralateral neurostimulator.

Electromagnetic Interference of Avalanche Transceivers with Cardiac Pacemakers and Implantable Cardioverter Defibrillators

Avalanche transceivers are essentials tools in locating persons who were buried by an avalanche. In the past few years, avalanche transceivers have become widely available and affordable, but it is largely unknown whether they are a source of electromagnetic interference for implanted cardiac devices. We aimed to determine the potential interaction between avalanche transceivers and pacemakers or implantable cardioverter defibrillators (ICDs). One hundred and one patients, 41 with pacemakers and 60 with ICDs, were enrolled (mean age 66 ± 15 years). Four avalanche transceivers (Pieps DSP [Pieps GmbH, Lebring, Austria], Ortovox x1, Ortovox m2, and Ortovox f1 [Otovox Sportartikel GmbH, Taufkirchen, Germany]) were evaluated in transmit as well as in receive mode. Surface electrocardiograms, intracardiac electrograms, and marker channels were continuously recorded and observed by an experienced physician. Electromagnetic interference events were categorized as direct interference with the function of the implanted device itself or as interference with the telemetric communication without compromising device function. Among all patients, there was no interference with the intrinsic function of their pacemakers or ICDs. A total of 120 episodes of telemetry interference occurred in 48% of the patients. Of those episodes, 112 of 404 (28%) were observed in transmit and eight of 404 (2%) in receive mode (P < 0.0001). The digital avalanche transceiver (Pieps DSP) was associated with significantly less telemetry interference (20/202; 10%) than the analog transceiver (Ortovox f1) (39/202; 19%) (P = 0.0108). Avalanche transceivers are safe for patients with pacemakers and ICDs. Despite the observed telemetry interferences, the intrinsic function of the implanted devices was never compromised.

Characteristics of Telemetry Interference with Pacemakers Caused by Digital Media Players

Contemporary implantable heart rhythm devices communicate multiple complex data simultaneously using radiofrequency telemetry. Interference in communication can expose them to the risk of potential corruption, leading to adverse clinical consequences. We studied the characteristics of interference with uplink (real time intracardiac electrograms, marker channel, and stored histograms) and downlink (attempt to program a change in the lower rate limit, the pacing mode, and the ventricular lead configuration) data transmission between the wand and the pacemaker caused by digital media players (iPods--Photo and 3G) in 50 patients. We also measured and characterized worst-case magnetic field emissions (MFE) from the wand (<or=0.4 microT), pacemaker (<or=0.004 microT), and iPod (<or=0.05 microT) during telemetry to understand the modulation techniques and safety protocols employed during data transmission. Telemetry interference (TI) manifested as high-frequency spikes (24.4%), blanking (17.7%) and interruption (22.2%), or delay (17.6%) in transmission with warning on programmer's screen. TI occurred in 25.6% of patients when the iPod was "on" and in 13% even with the iPod turned "off." There were no inaccuracies in downlinked data when the downlink communication was successful. Wanded telemetry utilizes low-frequency (30-300 kHz) radiowaves and simple digital modulation techniques at relatively slow rates for "sequential" data transmission protected by a continuous "handshake." Emissions from iPods in that range interrupt the telemetry link but are too weak to cause pacemaker malfunction through corruption of vital data. Low-power MFE from iPods can produce interference with establishment and maintenance of a telemetry link and can cause TI with transmission of real time data, but because of continuous check protocols, do not corrupt the stored and vital downlink data.

Do Media Players Cause Interference with Pacemakers?

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. 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. 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. 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

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. 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. 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. 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.

A Prospective Pediatric Clinical Trial of Digital Music Players: Do They Interfere with Pacemakers?

There has been recent concern in the media about iPod interference with pacemakers. We systematically tested two types of digital music players (DMP) on pacemaker or ICD function in children. Patients were monitored by a 6-lead ECG and programmer telemetry. The pacemaker was tested in bipolar and unipolar sensing at normal and maximal sensitivities. The order of DMP tested was randomized. Each DMP was placed on top of the pacemaker pocket, put into "play" mode three times (5 seconds each), with and without programmer wand placed one cm adjacent to DMP. Pacemaker interference was defined as: pacing inhibition, inappropriate pacing, oversensing, or detection of high-rate episodes associated with the use of DMP. Of the 67 patients (mean age 12 +/- 5 years), 62 had pacemakers and five had ICDs; 39 endocardial and 28 epicardial systems. Patients were tested with Sansa (67), iPod 30 GB (51), and other DMPs (43). There was no evidence of interference with pacemaker function by any DMP under any of the study conditions (each performed in triplicate). Reproducible programmer telemetry interference was shown in 11 cases (Medtronic 6/47, St. Jude Medical 5/18, Guidant 0/2) related to use of iPod (6), Sansa (1), or others (4). None of these were associated with any evidence of pacemaker malfunction. Interference with pacemaker function could not be shown with iPod or MP3 players. No additional precaution beyond standard is necessary for patients with pacemakers when they are using these players.

Electromagnetic interference with pacemakers caused by portable media players

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.

Telemetry Interference Likely to Increase as FCC Lifts Ban

Telemetry Interference Likely to Increase as FCC Lifts Ban

Telemetry Interference Likely to Increase as FCC Lifts Ban

Telemetry Interference Likely to Increase as FCC Lifts Ban

Comment on “A re‐examination of impulsive VLF signals in the night ionosphere of Venus”

Taylor and Cloutier (TC, 1988) previously argued that Singh and Russell (SR, 1986) wrongly identified telemetry interference as VLF broadband signals originating in Venus 'lightning events'. A response was made by Russell and Singh (RS, 1989). This comment criticizes RS, arguing that the SR did not distinguish between signal and noise and that RS makes false claims about the SR analysis. In a reply to TC, Russell argues that the SR paper, while flawed, was not intended to be quantitative and succeeds in bringing attention to the morphology of the signals seen in the upper three channels of the Pioneer Venus electric field detector.

Telemetry interference incorrectly interpreted as evidence for lightning and present‐day volcanism at Venus

Spike‐like responses to interruptions in the data recorded by the Orbiter Electric Field Detector (OEFD) on the Pioneer Venus Orbiter (PVO) have been incorrectly identified as broadband whistler noise and then interpreted as evidence of lightning and volcanism by Singh and Russell [1986; 1987]. We show that these spikes are non‐physical artifacts of the processing of interruptions in telemetry data and are readily distinguished from other non‐artificial noise appearing in the measurements. We independently analyze the spikes and the non‐artificial noise to show that key portions of the results of Singh and Russell are compromised by the inclusion of the artificial data. This conclusion is certified by the fact that (a) the distribution of the spikes‐only data matches the distribution of noise presented by Singh and Russell, while (b) the number and distribution of all non‐spike noise is quite incompatible with their results. This finding is consistent with our prior research, and leads us to reiterate that the PVO electric field data set used by Singh and Russell provides no basis for inferring the presence of either lightning or present‐day volcanism at Venus.