An automatic pacemaker sensing algorithm using automatic gain control

An automatic gain control (AGC) algorithm is implemented in a pacemaker to improve the sensing performance and minimize human intervention. The sensing amplifier gain is controlled automatically by the electrogram amplitude. The sensing threshold (sensitivity) is set between 20 and 30% of the intrinsic peak amplitude. The 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.