Rate responsive pacing using the ventricular gradient

摘要

A rate responsive cardiac pacing system is provided. In the illustrative embodiment, electrical st imulus pulses are applied to the heart ventricle and the evoked potential of the applied electrical stimulus pulses is detected. The detected potential is integrated over time to obtain a depolarization gradient magnitude. In one embodiment, the depolarization gradient magnitude is compared with a corresponding depolarization gradient magnitude of at least one previous cardiac cycle. In another embodiment, the repolarization gradient magnitude is compared with a corresponding repolarization gradient magnitude of at least one previous cardiac cycle. In a further embodiment, a peak to peak time interval is determined from the peak of the depolarization gradient to the peak of the repolarization gradient. The peak to peak time interval is compared to the peak to peak time interval of at least one previous cardiac cycle. The rate of the electrical stimulus pulses is controlled in response to these comparisons.