1. A medical device for detecting presence of a cardiac pulse, comprising: a piezoelectric sensor having a transducing element configured for placement on a surface of a patient's body, the transducing element being adapted to sense movement in the patient's body due to the cardiac pulse and produce piezoelectric signal data in response thereto; processing circuitry configured to analyze the piezoelectric signal data for a feature indicative of the presence of the cardiac pulse and determine whether the cardiac pulse is present based on the feature; and an electrotherapy generator for delivering pacing stimuli to the patient, wherein the processing circuitry analyzes the piezoelectric signal data to determine whether the cardiac pulse occurred in the patient in response to delivery of a pacing stimulus of the pacing stimuli, to the patient.