Abstract: A body stimulation system including external components for generating and transmitting programming signals and implantable components including a signal generator with at least one alterable operating characteristic, a stimulation signal delivering system and circuit responsive to receive programming signals for establishing the operating characteristic in predetermined correspondence therewith. The stimulation signal delivering system is connected to the operating characteristic establishing circuitry for receiving the programming signals. In a preferred embodiment, the external components are prevented from transmitting programming signals during a stimulation signal and, more preferably, for a predetermined period following a stimulation signal. The predetermined period may be established such that the external system is activated during the refractory period of the tissue being stimulated.

Abstract: A pacer having an upper and lower rate limit system for preventing pacer malfunction from producing pacer output pulses above or below preset maximum and minimum rates.