Method for heart transplant monitoring and analog telemetry calibration

摘要

A cardiac pacemaker with an analog telemetry system. A calibration circuit within the pacemaker is adapted to provide a reference signal of known character to the pacemaker's telemetry system. The reference signal is transmitted across the telemetry link as if it were an actual cardiac signal, and received by an external programmer. Since the reference signal has known, predetermined qualities, the programmer can automatically calibrate and scale the telemetry signal from the pacemaker, thereby increasing the accuracy of the telemetry channel. The increased accuracy is particular useful in assessing rejection of a transplanted heart, which is known to be associated with a 15% decline in the peak R-wave amplitude of the cardiac signal.