Passengers with Implanted Pacemakers and Cardioverter-Defibrillators: can they be safely screened by hand-held metal detectors?

20 Dec 2011

Clemens Jilek, Stelios Tzeis and Christian Kolb present their research into the safety of using hand-held metal detectors to screen passengers with implanted pacemakers or cardioverter-defibrillators.

Pacemaker and cardioverter defibrillator systems are routinely used for the treatment of cardiac arrhythmias. Function of these cardiac rhythm devices can be impaired by electromagnetic interference from devices and systems emitting magnetic fields, such as cellular phones (1), MP3-players, 50/60 Hz alternating current, induction ovens, and anti-theft protection devices (2, 3).

Security screening at airports has intensified over the last decade, following the 11th September 2001 attacks.  Metal detectors are routinely used for detection of ferrous items on passengers. They create a magnetic field that might interfere with implanted cardiac rhythm devices. Therefore people with implanted pacemakers or cardioverter-defibrillators are routinely advised to avoid screening with metal detectors, due to the risk of possible electromagnetic interference. Is concern justified?

We have previously shown that metal detector gates are safe for patients with cardiac rhythm devices (4): A total of 345 people, 200 with implanted pacemakers and 145 with implanted cardioverter-defibrillators, were tested with an airport metal detector gate – CEIA’s Model 02PN10 – creating a maximal electromagnetic ?ux density of 42 ?T. No electromagnetic interference was observed. However security protocols dictate that once metal detector gates indicate the presence of ferrous material, hand-held metal detectors should be used to verify and locate the suspected object of interest. The US Food and Drug Administration has reported 44 instances of possible interference between hand-held metal detectors or anti-theft protection devices and cardiac rhythm device systems (5).

The objective of our study was to systematically assess the risk of electromagnetic interference between two broadly used hand-held metal detectors and implanted pacemakers and cardioverter-defibrillators.

Methods

Patients presenting for routine follow-up of pacemaker or cardioverter-defibrillator function in two hospitals (German Heart Center Munich, Germany and Henry Dunant Hospital Athens, Greece) between September 2009 and December 2010 were screened for participation. A proper device function was obligatory before testing with hand-held metal detectors. The device parameters were changed to make interferences obvious in the connected electrocardiogram for pacemakers and cardioverter-defibrillators and to make the detection of arrhythmias more likely for cardioverter-defibrillators. Informed consent was obtained from all patients before testing for interference with the hand-held metal detectors. The study was approved by each of the local ethics committees.

Hand-held metal detectors

We tested two commercially available hand-held metal detectors that are widely used in Europe: a PD 140 device (CEIA S.p.A., Arezzo, Italy) that is usually used at airports, and a MH 5 device (Vallon GmbH, Eningen, Germany) that is mainly used in public services. We programmed both at maximal sensitivity (PD 140 maximal electromagnetic ?ux density 3.82 ?T, MH 5 maximal electromagnetic ?ux density 6.3 ?T).

Test protocol

Patients were examined in supine position under continuous 12-lead electrocardiogram (ECG) monitoring. Documentation of stored and programmed parameters was performed before and after exposure to the hand-held metal detectors to detect changes in parameter settings or inappropriate function. During continuous ECG recording, we swiped the activated hand-held PD 140 and MH 5 metal detector on the skin above the cardiac rhythm device and along the lead(s) for ?30 seconds.

Results

388 patients (mean age 66±15yrs, 76% males) participated in the study. 209 patients had pacemaker systems, comprising 81 devices from 37 model families of 11 manufacturers corresponding to 73% of all pacemaker families available on the market within the last ten years. 179 patients had cardioverter-defibrillator devices, comprising 61 devices from 26 model families of 7 manufacturers corresponding to 76% of cardioverter-defibrillator families available on the market within the last ten years.

We observed no abnormal pacemaker or cardioverter-defibrillator system function during or after exposure to handheld metal detectors. For a detailed list of the device models please see the original article in the Annals of Internal Medicine (6).

Discussion

In this assessment of interference between commonly used hand-held metal detectors and a variety of cardiac rhythm devices we were unable to identify any adverse effects of use on cardiac device function. We aimed to maximise the likelihood of interference by using the highest possible magnetic field of two commonly used hand-held metal detectors and by increasing the duration of exposure to 30 seconds per testing, which by far exceeds conventional screening durations. Aiming to increase the generalisability of our results, we used in our testing protocol two commercially available, widely applied, hand-held metal detectors with different strengths of magnetic field and technical characteristics similar to those of other hand-held metal detector systems used for screening procedures.

Our results are consistent with previous studies which showed no electromagnetic interference when device recipients walked through metal detector gates which cause an electromagnetic field of even higher strength compared to hand-held metal detectors (4, 7).

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