The ventricular fibrillation is still the main cause of a sudden cardiac death, even though it was described 155 years ago in experiment (M. Hoffa 1849) and its therapy--defibrillation--has been known since 1947 (C. Beck). In Europe 2500 inhabitants suffer from cardiac arrest daily and 90% is caused by ventricular fibrillation. A key interval for an effective defibrillation seems to be 3-8 minutes from the begining of a cardiac arrest. Automated (automatized) external defibrillators (AED) have been used for last 15 years, especially in USA. However it is still unclear how many devices will be needed and where to place them. We don't know if they improve the prognosis of patients with out of hospital cardiac arrest during ventricular fibrillation. The individualisation of the risk of a sudden cardiac death has brought a new method to the clinical practise--implantation of cardioverter-defibrillator (ICD). Their efficacy in reduction of total mortality was verified first in the field of secondary prevention--in patients after cardiac arrest (AVID study) and than in the field of primary prevention--in patients with risk markers (left ventricle dysfunction, non sustained ventricular tachycardias) but without sustained malignant arrhythmia in anamnesis (MUSTT, CIDS, MADIT I, MADIT II). Defibrillators (external, automated, implantable) obviously don't mean the end of the sudden cardiac death. The incidence of sudden cardiac death can be reduced significantly with prevention (nutrition, prevention of CAD) and one attention should be drawn to the fact even in the future.