The proposed cellular mechanism for CPVT pathogenesis is based on the aberrant SR Ca2+ release activating the electrogenic sarcolemmal NCX to extrude the cytosolic Ca2+, causing membrane depolarization and triggering early or delayed after depolarizations (Knollmann et al. 2006; Rizzi et al. 2008). The gene discussed is TLX2; the disease is catecholaminergic polymorphic ventricular tachycardia.