The implantable cardioverter defibrillator (ICD) has undergone a remarkable transformation in the last three decades, both in generator size and functionality. This, coupled with improvements in lead design, allows the simplicity of defibrillator implantation to approach that of pacemakers, with outpatient placement now feasible. Nowadays, the majority of new ICD implants are performed on primary prevention grounds with device longevity of more than 7 years. In this article, we will concisely explain the evolution of this treatment, the implantation technique, arrhythmia detection and patient follow-up. In addition, we will review the relevant clinical trials as well as prescription guidelines.