Effects of mobile telephones on the function of implantable cardioverter defibrillators

Abstract

Objective: We investigated whether mobile telephones affect the function of implantable cardioverter defibrillators (ICDs).

Background: It is well known that electromagnetic fields can affect medical devices.

Methods: The study included 43 patients with ventricular tachycardia and/or fibrillation treated with transvenous pectoral ICDs. Testing was done under continuous electrocardiograph monitoring under supervision of an ICD programmer. Initially, each patient was tested during spontaneous rhythm. Then the ICD was programmed to a pace rhythm higher than the patient's heart rate, and the tests were repeated at paced rhythm. In 7 patients, tests were performed during the implantation procedure as well. In 3 of the patients, only a single defibrillation zone was active. The other 40 patients had one or more active ventricular tachycardia zones. Two mobile phones (both GSM 900 MHz) were positioned 50 cm away from the implanted device in opposite directions and switched on. Communication was established between these phones, two investigators had a 20-second conversation, and then the phones were switched off. The same procedure was repeated at 30, 20, and 10 cm away from the implantation site, respectively. Finally, the procedure was performed with the antennae of both phones touching the device pocket. In the above-mentioned 7 cases where testing was done during implantation of the ICD, a call was made from one phone to the other, ringing occurred for 5 seconds, and then two investigators conversed while the device was implanted.

Results: There was no change in the function of the ICDs during any of the phone testing procedures. In 5 cases, artifacts were noted on the surface electrocardiographic (ECG) screen of the programmer during the tests, but no such changes were observed on the simultaneous intracardiac ECGs.

Conclusion: The results of the study suggest that mobile phones have no effects on ICD function.

Figure 1

The programmer electrocardiogram (top trace) of one ICD recipient (Patient 40) showed artifacts (indicated by arrows) while the one mobile phone was ringing, and while the investigators were communicating over the two phones (→). The simultaneous intracardiac electrocardiogram revealed no artifacts. The artifacts disappeared when the mobile phones were switched off (→).