The number of patients receiving implantable cardiac devices annually in the United States has more than tripled from 133000 in 1990 to 412000 in 2003. Combined with an exponential increase in the complexity of these devices, traditional methods of device follow-up in physician offices and follow-up clinics are increasingly unable to handle the demand. Over the past 2 years, follow-up systems have been introduced that can remotely interrogate implantable cardiac devices. Each manufacturer has taken a different approach in system design and implementation, although all include a home device interrogator, transtelephonic data transfer, and Internet-based clinician viewing systems. Medtronic’s CareLink system (Medtronic Inc, Minneapolis, MN), for example, was designed to improve follow-up efficiency, with an average patient encounter declining from 24 to 8 minutes of expended clinic time. Enhancements in efficiency result from asynchronous communication between patient and clinician, batch patient transmission of data, and clinician batch processing of data [1]. St Jude Medical’s Housecall System (St Paul, MN) had a different design philosophy, having patients maintain synchronous communication with a technician on the telephone. Patients transmit a surface electrocardiogram (ECG) using standard frequency-modulated transtelephonic technology, with the addition of digital interrogated device data. A technician at a call center or in the follow-up clinic maintains communication with the patient while reviewing the real-time ECG and the interrogated data. Biotronik’s Home Monitoring System (Biotronik GmbH, Berlin, Germany) was developed with yet another design philosophy, specifically, that device followup will continue to be done in device follow-up clinics, yet patients can have continuous monitoring of arrhythmias. The Biotronik system uses the 402- to 405-MHz Medical Implant Communication Systems band, with the implanted device sending up to 128 bytes of data over a several-meter distance to a custom telephone, which then transfers the data either to a call center or to a clinical office. Currently, reimbursement isavailableforcompleteremoteinterrogationofanimplanted defibrillatorinmoststates,butreimbursementisnotavailable