Characteristics of telemetry interference with pacemakers caused by digital media players.

BACKGROUND: 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. METHODS & RESULTS: 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 (

Electromagnetic interference in an implantable loop recorder caused by a portable digital media player.

The implantable loop recorder has been shown to be a cost-effective tool for diagnosis of intermittent cardiovascular symptoms such as syncope and palpitations. Electromagnetic interference in these recorders may be caused by commonly encountered electronic devices such as antitheft electronic surveillance systems and magnetic resonance imaging cameras. In this report, we describe interference in two patients with implantable loop recorders from a portable digital media player.

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.

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.

Electromagnetic interference with pacemakers caused by portable media players.

BACKGROUND: 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. OBJECTIVE: The purpose of this study was to determine if iPods cause interference with pacemakers. METHOD: 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. RESULTS: 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. CONCLUSION: iPods placed within 2 inches of implanted pacemakers monitored via the telemetry wand can cause interference with pacemakers.