Patent ID: 7844334

Claim:
An implantable medical device, comprising: a sensing circuit configured to sense at least one electrogram; a pacing circuit configured to deliver pacing pulses; a dual-use sensor configured to sense a signal indicative of physical activities and heart sounds; a preconditioning circuit configured to precondition the sensed signal, the preconditioning circuit including a preconditioning amplifier having a preconditioning gain, a preconditioning band-pass filter having a set of preconditioning cutoff frequencies, and an analog-to-digital converter (ADC) to produce the preconditioned sensed signal by amplifying, filtering, and digitizing the sensed signal; a sensor processing circuit configured to produce an activity level signal and a heart sound signal using the preconditioned sensed signal, the activity level signal indicative of a level of the physical activities, the heart sound signal indicative of the heart sounds, the sensor processing circuit including: a first set of cutoff frequencies suitable for producing the activity level signal; a first gain suitable for producing the activity level signal; a second set of cutoff frequencies suitable for producing the heart sound signal; and a second gain suitable for producing the heart sound signal; an implant controller coupled to the sensing circuit, the pacing circuit, and the sensor processing circuit, the controller configured to control the delivery of the pacing pulses using the activity level signal and the heart sound signal; and an implantable housing encapsulating at least the sensing circuit, the pacing circuit, the sensor processing circuit, and the controller.