Abstract: An implantable medical device for producing a variable therapeutic output to a patient. A therapeutic output delivery module requires replenishment following delivery of a predetermined amount of the therapeutic output. A calculator is responsive to a measure of an amount of the therapeutic output actually delivered to the patient for determining a parameter representative of a time at which the therapeutic output delivery module of the implantable medical device should be replenished with the therapeutic substance based at least in part upon the amount obtained from the measure. A method determines a parameter representative of a time at which a therapeutic output module of an implantable medical device should be replenished following delivery of a predetermined amount of therapeutic output. An amount of the therapeutic output actually delivered to the patient is measured. The parameter is calculated based at least in part upon the amount obtained in the measuring step.

Abstract: A pulse rate sensor that includes an accelerometer for measuring periodic motion and a piezo sensor for detecting erratic motion is capable of more accurately determining pulse rate by accounting for these types of motion. The pulse rate sensor in accordance with the present invention diminishes pulse rate signal degradation due to erratic motion through a combination of algorithms that control signal boosting, waveform refinement and signal noise suppression.