Background: Use of communication devices in the hospital environment remains controversial. Electromagnetic interference (EMI) can affect different medical devices. Potential sources for EMI on ECG machines were systematically tested. Hypothesis: Communication devices produce EMI on ECG machines. EMI impairs ECG interpretation.Methods: The communication devices tested were: a global system for mobile communication (GSM) receiver, a code division multiple access (CDMA) receiver, an analog phone, a wireless local area network, and an alpha-numeric pager. EMI was tested on 3 ECG machines: MAC 5000, MAC 1200, and ELI 100. The devices were tested at 2 and 1 meter, 50, 25, and 0 cm from the acquisition module. The ECGs were presented to a heterogeneous group of clinical providers, (medical students, residents, nurses, industry representatives from cardiac devices companies, and attending cardiologists) to evaluate the impact of EMI on ECG interpretation skills. Results: EMI was detected on the MAC 5000 ECG machine when activated GSM, CDMA, and analog phones were placed on top of the acquisition module. No EMI was seen on the other ECG machines or when phones were at a longer distance or deactivated. EMI was incorrectly diagnosed in 18% of the cases. EMI was confused most frequently with atrial fibrillation or flutter (52%), ventricular arrhythmias (22%), and pacemaker dysfunction (26%). Medical students ( p<0.003) and non-cardiology residents ( p = 0.05) demonstrated significantly worse performance on EMI interpretation. Conclusions: Digital and analog phones produce EMI on modern ECG machines when activated in direct contact to the acquisition module. EMI impairs ECG interpretation.

We present a series of three cases of patch testing confirmed cardiac rhythm device induced contact dermatitis. In the first two cases, there was complete resolution with device extraction and reimplantation with another device with either an absence of the offending agent or a coating with another resin or metal. These cases illustrate the difficulties in diagnosing pain, tenderness, and dermatological manifestations in patients with cardiac rhythm devices (pacemakers and implantable cardioverter defibrillators).