However, the recent research has led to the discovery of several CaM mutations in a small group of patients presented mainly with cardiac specific phenotypes, such as long QT syndrome (LQTS), idiopathic ventricular fibrillation (IVF), and catecholaminergic polymorphic ventricular tachycardia (CPVT). This evidence concerns the gene CALM2 and paroxysmal familial ventricular fibrillation.