Transcutaneous communication system using the human body as conductive medium: influence of transmission data current on the heart.

We developed a new transcutaneous communication system (TCS) that uses the human body as a conductive medium for monitoring and controlling artificial hearts and other artificial organs in the body.In this study, the physiological effect of data current discharged into the body during data transmission was evaluated by an animal experiment using a goat. The external and internal units of the new TCS each mainly consist of a data transmitter and a data receiver. The data transmitter has an amplitude shift keying (ASK) modulator (carrier frequencies: 4 and 10 MHz) and an electrode.The internal unit of the TCS was fixed on the pericardium and the external unit was placed on the left ear, and each transmitter discharged an ASK-modulated current of 7 mA (RMS) into the conscious goat. The TCS was able to transmit data for 4 weeks under full duplex communication with a transmission rate of 115 kbps. On the 28th postoperative day, an electrocardiogram was measured during data transmission. Cardiac rhythm and waveform of the electrocardiogram were not changed before and during bidirectional data transmission. Also, no adverse effect on the heart was observed by autopsy.