Sudden cardiac death - a known unknown?

Sudden cardiac death (SCD) is a major medical, economic and social problem. The estimated annual number of SCDs is approximately 4 million cases worldwide. Approximately 50% of SCDs are unexpected first manifestations of cardiac disease. The survival rate after out-of-hospital cardiac arrest is low even in countries with the most advanced health care systems. It all emphasizes the importance of prevention, in which implantable cardioverter-defibrillators play a dominant role. However, our ability to recognize high-risk patients remains insufficient. Moreover, a declining rate of shockable rhythm as the initial recording has been reported in the last decades. Despite numerous SCD studies and undisputed progress, there are still many unanswered questions.