A non-invasive bodily-attached ambulatory medical monitoring and treatment device with pacing is provided. The device includes at least one therapy electrode; a memory storing information indicative of a patient's cardiac activity; circuitry for implementing a plurality of pacing routines, each pacing routine of the plurality of pacing routines corresponding to at least one cardiac condition of a plurality of cardiac conditions; and at least one processor coupled to the circuitry and configured to identify, within the information, at least one cardiac condition of the plurality of cardiac conditions; and respond to the identified cardiac condition in part by causing execution of at least one pacing routine corresponding to the identified cardiac condition.