A leadless cardiac pacemaker comprises a housing, a plurality of electrodes coupled to an outer surface of the housing, and a pulse delivery system hermetically contained within the housing and electrically coupled to the electrode plurality, the pulse delivery system configured for sourcing energy internal to the housing, generating and delivering electrical pulses to the electrode plurality. The pacemaker further comprises a temperature sensor hermetically contained within the housing and adapted to sense temperature information, wherein the pacemaker can control electrical pulse delivery at least partly based on the temperature information.