An automatic pacemaker sensing algorithm using automatic gain control

An automatic gain control (AGC) algorithm is implemented in a pacemaker to improve sensing performance and minimize human intervention. The sense amplifier gain is controlled automatically by electrogram amplitude. The sensing threshold (sensitivity) is set between 20 and 30% of the intrinsic peak amplitude. Sensing performance of the AGC algorithm is evaluated using 12 human intracardiac electrograms. The performance is compared to that of a conventional fixed sensing method utilizing an optimal threshold. The results from the evaluation indicate that the sensing capability of the automatic sensing algorithm is as good as or better than the conventional fixed sensing threshold method and that the AGC adjusts both amplifier gain and sensing threshold appropriately without human intervention.