A medical device system includes electrodes for delivering cardiac pacing pulses to a patient's heart, a cardiac sensing module coupled to the electrodes and a cardiac pacing module coupled to the electrodes for generating cardiac pacing pulses. An acoustical sensor is used for obtaining heart sound signals. The system includes a processor that is configured to establish multiple conditions during which heart sound signals are received. The processor derives heart sound signal parameters from the heart sound signals and determines a heart sound profile comprising a trend of each of the heart sound signal parameters with respect to the multiple established conditions.