Sudden cardiac death (SCD) is usually the result of a cardiac arrhythmia, mainly ventricular fibrillation, and is one of the leading causes of death in the occidental world, accounting for 300,000 to 500,000 deaths each year only in the United States. The scientific debate is still open about the risk factors leading to SCD; that knowledge represents a crucial step in order to solve and prevent this too common problem. The correct identification of the risk factors for sudden death can favour the correct strategies to minimise this risk. Those are mainly the type and severity of underlying heart disease as well as specific electrophysiologic findings diagnosed at EKG or through other specific tests. The optimal treatment of some of those diseases such as the most known ischemic heart disease can minimize the risk of SCD during follow-up. However many people continue to die from ventricular fibrillation, because not always predictable and often due to direct the delay inherent in getting an ambulance to the cardiac arrest victim within those critical first 5 minutes. In the mid-1990s, a new generation of computerized defibrillators was introduced. These devices, called Automated External Defibrillators (AED), are capable of interpreting a person's heart rhythm and delivering a defibrillation shock with only minimal input from the operator. Today, many states have true public access defibrillation programs and in USA recently FDA allowed their selling in the food and drug stores. This book provides review in-depth of all important aspects of SCD and contemporary guidelines concerning risk stratification and therapeutic approaches. The major treatments for patients at very high risk for sudden cardiac death include implantable cardiac defibrillators, pacemakers, and anti-arrhythmic medications. The main purpose of this book is to enphasize the importance of adequate clinical approach to patients at risk and to describe the rationale for clinical management of these patients. In addition the way to develop early defibrillation programs in the community will be extensively considered.