Schematic depiction of Nav1.5 linear topology illustrating the localization of SCN5A ultra rare variants observed in individuals with a default diagnosis of idiopathic ventricular fibrillation. Dark blue circle denotes a loss-of-function variant identified in the current study. Light blue circles denote wild-type variants identified in the current study. Orange circles denote loss-of-function variants identified in prior studies. ^aVariant(s) identified in an individual(s) with evidence of conduction delay and/or early repolarization.