RESUMO
To investigate the influence of Global System of Mobile (GSM) telephones on permanent pacemakers, four brands of GSM telephones: Panasonic, Motorola, Nokia, Ericsson, and 24 permanent pacemaker, 17 models of five major brands, were tested in their original sterile packages. Pacemaker brands tested were Pacessetter, Cardiac Pacemakers Inc. (CPI), Vitatron, Medtronic and Intermedics. The effects of switching on and off, ringing and transmission were tested and marker channel recordings were made connuously. Tests were carried out for each model of GSM telephone wile the telephone was immediately on or up to 15 cm above the pacemaker box. No program chagne was noted in any of the pacemakers. All CPI models tested, Synchrony II of Pacesetter, Unity of Intermedics, and Thera SR of Medtronic were unaffected. However all remaining models showed intermittent and/or continuous inhibition of 2-13 seconds and inappropriate triggering of impulse when the telephones were placed on the package. Interference dsppeared beyond 15 cm in all pacemaker models. O ne pacemaker, AFP of Pacesetter implanted 8 years ago, induced VT as long as the patient tried to keep the telephone active over either ear. In conclusion, patients with permanent pacemakers shoud be advised not to use GSM telephones until further tests prove their safety.