Encouragingly, the majority of studies to investigate the effect of SEA0400 on arrhythmia reported positive results, i.e., antiarrhythmic efficacy (Nagy et al., 2004; Milberg et al., 2012) in absence of negative inotropic effects (Bourgonje et al., 2013) thus potentially qualifying the concept of NCX inhibition as a promising antiarrhythmic strategy. This evidence concerns the gene TLX2 and cardiac arrhythmia.