Abstract: The sense margin evaluation system and method for use of same is based upon (1) the interposition of a variable broad-band attenuator between an implanted cardiac pacer lead set and a pacer which is about to be implanted and (2) the inclusion of a pacer pulse detector at the pacer port. In use, the pacer is first programmed to a standby mode and a condition of 100% inhibition with the attenuator set to 0 dB. This affirms that the pacer's sense amplifier can sense the cardiac signal. Then, attenuation is incrementally added until the pacer just begins to output. The attenuation ratio (input/output) at this point is a direct measure of the ratio effective between the patient's cardiac signal and the pacer's sensing threshold, i.e., the sense margin.