There is now increasing evidence that the modulatory role of CaMKII can become overactive in HF and this can have deleterious consequences for intracellular Na+ (Grandi & Herren, 2014) and Ca2+ regulation (Mattiazzi et al., 2015) and be proarrhythmic (Hund & Mohler, 2015). This evidence concerns the gene CAMK2G and hydrops fetalis.