Here we revealed for the first time in human CMs, that flecainide does not prevent the pathological Calstabin2 depletion in CPVT cells which is known to be associated to leaky RyR2 channels [15,16,17,19,20,30,31,32,33,34,35]. The gene discussed is RYR2; the disease is catecholaminergic polymorphic ventricular tachycardia.