RYR2 and hydrops fetalis: (a, b) Representative Western blots and quantification of the relative expression of Ca2+/calmodulin-dependent protein kinase II (CaMKII)-phosphorylated RyR (S2814), protein kinase A (PKA)-phosphorylated RyR (S2808), and total RyR in sham and HF cardiomyocytes (sham: nhearts = 5; HF: nhearts = 5).