Development of a Remote Monitoring System with PHS for Patients with Implantable Left Ventricular Assist System.

The usefulness of a remote monitoring system that uses a PHS (Personal Handy-phone System) and a GPS (Global Positioning System) for artificial heart-implanted patients was investigated. The PHS has several advantages: high-speed data transmission, and little electromagnetic interference with medical devices, etc. In our system, patients have the PHS and a mobile computer for data transmission control between an implanted controller and a host computer in the hospital, and also a GPS receiver for location of patients. Information on motor rotational angle and motor current of the implanted motor-driven heart is fed into the mobile computer from the implanted controller according to 32-bit command codes from the host computer. Motor current and motor rotational angle data from inside the body are framed together by a control code (frame number and parity) for data error checking and correcting at the receiving site, and the data are sent through the PHS connected to the mobile computer. GPS positioning data and battery data from the mobile computer are also sent to the host computer with control codes. The host computer calculates pump outflow and arterial pressure from the motor rotational angle and motor current values and displays the data in real-time waveforms. The host computer also displays patient's position on the map and batteries' condition. The results of this study showed that accurate data could be transmitted from the subjects while they were walking or driving a car to the host computer at a data transmission rate of 32kbps, and that driving condition of the artificial heart and subject's position could be remotely monitored on the host computer. This system is useful for remote monitoring of patients with an implanted artificial heart.