In-vitro assessment of the effects of cellular phones on implantable cardioverter defibrillator (ICD) function

The design of cardiac pulse generators has evolved from an artificial pacemaker single therapy device to a multifunctional therapeutic device known as an implantable cardioverter defibrillator and pacemaker. Composed of complex digital circuitry and discrete components, these devices may exhibit susceptibility to EMI. Despite shielding the internal mechanism of pacemakers and ICDs with titanium casing and using improved noise filtering techniques, new sources of EMI continue to pose challenges in EMC design of these devices. There have been previous reports of interference from RF sources such as radar transmitters, hand-held radios, and anti-theft devices. More recently, with the proliferation of wireless communication, reports of interference by digital cellular telephones have also surfaced. FDA/CDRH initiated an examination of the potential for cellular telephones to interfere with implanted pacemakers in 1995. Results of these evaluations led CDRH engineers to investigate the potential EMI effects of these telephones to ICD function. The investigation involved ICDs from six manufacturers versus four types of digital cellular telephones. An RF powered dipole antenna was also used to evaluate it as an alternative RF source for EMI testing.