The inherited short QT syndrome (SQTS) is a novel, genetically determined arrhythmia that resembles the pathophysiological counterpart of congenital long QT syndrome (LQTS). Gain-of-function ion channel mutations in cardiac potassium channel genes are the currently known cause of SQTS and obvious genetic heterogeneity is evident from the few reported families. At present, three subforms are known, and probably, specific T-wave patterns make each subform recognizable. So far, only a few cases have been genetically unraveled. Treatment includes ICD implantation as the first-line option due to a high occurrence rate of ventricular fibrillation and repolarization-prolonging medications such as quinidine are under investigation. Whenever atrial and/or ventricular fibrillation occur in an idiopathic setting, SQTS has to be considered a potential cause.