Cardiologists are in charge of the follow-up of patients equipped with pacemakers and defibrillators. In many situations, however, the non-specialist will have to take care of these patients. It is therefore essential that the practitioner understands the basics of how these devices work, the potential complications and the situations in which the cardiologist's intervention is necessary. This article summarizes implantation techniques, post-operative follow-up and potential complications of implantable devices. It recapitulates the differences between pacemaker, defibrillator and resynchronization therapy. It explains the stimulation modes and reminds the reader how the magnet works and the precautions to be taken in the operating theatre, during magnetic resonance imaging or in situations of emergency.