Abstract: A method and apparatus for automatically adjusting the sensing threshold in an automatic implantable cardioverter/defibrillator with pacing capability. Fixed sensitivity is used for a specified interval following each pacing pulse and automatic sensitivity adjustment is used when spontaneous cardiac depolarization is detected. For spontaneous cardiac depolarization, the sensing threshold is automatically adjusted to a value proportional to the amplitude of the sensed cardiac signal. The sensing threshold continuously decreases between sensed cardiac depolarizations, ensuring that a lower level cardiac signal will be detected. When a pacing pulse is delivered, the sensing threshold is set to a fixed value and held at that value for a predetermined period of time such that the sensing threshold will not be affected by the cardiac response evoked by the pacing pulse. At the end of the predetermined period of time, the sensing threshold is decreased as it would following a spontaneous cardiac depolarization.