In line with our hypothesis that SK4 K+ channels are involved in atrial remodeling in the context of HF, we found that SK4 K+ channel expression in the LA, as measured by immunohistochemistry (IHC), was noticeably upregulated in vehicle-injected rats subjected to MI as compared to control rats (Fig. 4). The gene discussed is KCNN4; the disease is hydrops fetalis.