As with dantrolene, JTV519 is more effective with N-terminal and central domain RyR2 mutations than with C-terminal domain mutations (Tateishi et al., 2009), again showing a broad domain-specific action and providing a further example of the unzipping model in CPVT (Figure 2B). The gene discussed is RYR2; the disease is catecholaminergic polymorphic ventricular tachycardia.