Mice with targeted disruption of eNOS had a higher incidence of arrhythmias induced by ouabain (Rakhit et al., 2001) or β-adrenergic stimulation (Wang et al., 2008), confirming earlier work reporting on the protective effects of NO against ventricular arrhythmias in dogs (Vegh et al., 1992). The gene discussed is NOS3; the disease is cardiac arrhythmia.