Indeed, an increase of the spontaneous Ca2+ leak through RyR2 has been observed in HF (Fischer et al., 2014; Ho et al., 2014; Grimm et al., 2015; Fu et al., 2016; Uchinoumi et al., 2016; Walweel et al., 2017; Dries et al., 2018). This evidence concerns the gene RYR2 and hydrops fetalis.