IP3R expression has been shown to increase in heart failure (Marks, 2000) and in atrial fibrillation (Yamada et al., 2002), which raises the possibility that this IP3-TRPC signaling system may become more important in pathological conditions (Worley et al., 2007; Ju et al., 2012). This evidence concerns the gene ITPR1 and atrial fibrillation.