KCNJ3 and atrial fibrillation: For instance, it has been reported that mice with cardiomyocyte-restricted constitutive activation of the NLRP3 inflammasome have increased atrial ectopic activity and AF susceptibility, as well as enhanced mRNA expression of key ion channel subunits (RyR2, Kv1.5, GIRK1, and GIRK4) (6).