A method, system and device for monitoring and treating conditions of a mammalian heart, among which may include bradyarrhythmias, tachyarrhythmias and heart failure, the device being configured as a pacemaker that harvests energy as it implements the pacemaker functions to treat and monitor conditions of the heart. The pacemaker has a case, electrical circuitry sealed within the case, an electrode that is electrically coupled to the electrical circuitry, and embodiments may include a microelectromechanical system (MEMS) for harvesting and converting the kinematic energy of the heart into electrical energy. Embodiments provide receivers at locations of the heart which sense heart activity and are controlled with pacing circuitry to deliver electrical impulses at locations and time intervals to replicate the contractions of a normal functioning heart. Further embodiments provide a multi-part pacemaker where case-connectable electrode part may be implanted separately from the case part.
