RYR2 and hydrops fetalis: L-type calcium (Ca2+) channel (LTCC) phosphorylation raises the L-type Ca2+ current (ICa,L) [7], and phosphorylation of the sarcoplasmic reticulum (SR) ryanodine receptor (RyR2) [8] increases further the intracellular concentration of Ca2+ ([Ca2+]i; although controversy persists regarding the role of RyR2 phosphorylation in cardiac physiology and HF pathophysiology) [9, 10].