Electrical storm (ES) is defined as ventricular tachycardia or ventricular fibrillation occurring at least three times in 24 h leading to hemodynamic unstable state that needs cardioversion or defibrillation. ES may cause fast hemodynamic impairment, leading to “low-perfusion” or “no perfusion” state of the organs, a vicious circle pointing toward cardiogenic shock, multi-organ failure, and pulseless electrical activity. ES in ICD patients may be a strong predictor of arrhythmic and nonarrhythmic death, as well as of rehospitalization. The first step is to start cardiopulmonary resuscitation to achieve complete hemodynamic stabilization to prevent the low-flow or no-flow state. The patient has to be transported to an intensive care unit for further specific treatment. The arrhythmia should be treated with specific antiarrhythmic agents, for example, amiodarone, lidocain and bretylium, and then all the reversible causes have to be detected and treated as fast as possible. Underlying heart disease determines the specific treatment such as coronary revascularization, mechanical circulatory and respiratory support, and ablation of the arrhythmic foci.