Missense mutations in calmodulin (CALM) can cause ventricular arrhythmia manifesting as long QT syndrome (LQTS), catecholaminergic polymorphic ventricular tachycardia (CPVT), and idiopathic ventricular fibrillation (1). This evidence concerns the gene CALM1 and catecholaminergic polymorphic ventricular tachycardia.