CALM3 and familial long QT syndrome: In the past few years our knowledge on calmodulinopathy has expanded and it is now known to be a severe arrhythmogenic condition that can manifest mainly as LQTS (6), catecholaminergic polymorphic ventricular tachycardia (9) or idiopathic VF (IVF) (10) caused by genetic mutations in any of the 3 calmodulin genes (CALM1, CALM2, CALM3).