SCN3B and Ventricular arrhythmia: The NaV β-subunits play a critical role in the regulation of cardiac NaV channel function, as demonstrated in SCN1B- and SCN3B-null mice whose ventricular cardiomyocytes exhibit abnormal electrophysiology and propensity to ventricular arrhythmias (Lopez-Santiago et al., 2007; Hakim et al., 2008; Lin et al., 2015).