Abstract: An apparatus for remotely monitoring the performance of an implanted cardioverter defibrillator includes a remote apparatus adapted which receives commands from and transmits data to a central monitoring facility over telephone communication channels. The remote apparatus includes equipment for acquiring a patient's ecg waveform and transmitting that waveform to the central facility over the telephone communication channel. The remote apparatus also includes a segment, responsive to a command received from the central monitoring facility, for enabling the emission of audio tone signals from the cardioverter defibrillator. These audio tones are detected and sent to the central monitoring facility via the telephone communication channel. The remote apparatus also includes patient alert devices which are activated by commands received from the central monitoring facility over the telephone communication channel.