Under certain circumstances, mobile phones can have adverse effects on the function of pacemakers, but the devices usually start working properly again once the phones are moved away, researchers in Turkey report.

“Patients must not get into a panic about this issue (because) modern pacemakers are quite protected devices from interference,” said Dr. Izzet Tandogan.

Tandogan, of the University of Cumhuriyet, Sivas, and colleagues examined the effects of mobile phones on pacemaker function in a study involving 679 patients with permanent pacemakers.

During the tests, two mobile phones were symmetrically placed on both sides of the implanted pacemaker with the antennas being equidistance at 50, 30, 20, and 10 cm. The team performed the tests when both mobile phones were opened, on stand-by, receiving a call, during the call and closed.

Thirty-seven patients with pacemakers (5.5 percent) were adversely affected by the mobile phones, the team reports in the International Journal of Cardiology.

About half of the adverse effects occurred when the phone was 10 cm or closer to the pacemaker. The older the pacemaker, the more likely it was to be affected by the phones, the investigators found.

However, no permanent changes in pacemaker programs or function were observed.

“The most essential recommendation to patients is that mobile phones must be kept at least 20 cm away from pacemakers,” Tandogan said in an interview.

“For this purpose, it is sufficient for patients not to use the ear on the side of the pacemaker while talking on the mobile phone and not to carry the mobile phone in the shirt pocket on the side of the pacemaker,” he explained.

Patients who need to be most careful are those who are “without spontaneous cardiac rhythm and completely dependent on pacemakers, in whom pacemaker inhibition can lead to a drastic and fatal outcome.”

Despite the note of caution, Tandogan said a lot more needs to be clarified about this issue. “Vulnerability of pacemakers made by various manufacturers and effects of mobile phones produced by different firms, and the effect of mobile phone base stations, are other subjects to be investigated.”

SOURCE: International Journal of Cardiology, August 2005.