SCN1A and atrial fibrillation: While a high percentage of NP cells expressed the Cav2.2 channel relative to AF cells, in contrast to the lack of Nav1.1, Kv3.3 and CACNA2D1 staining in the NP, many different factors could be responsible for differential expression levels, such as glucose concentration46 and pH,47 which themselves are different across the IVD.48