Although NCX1 expression is often increased in the setting of LV dysfunction in HF, this does not necessarily lead to increased NCX1 activity (Hobai and O’Rourke, 2000; Quinn et al., 2003), suggesting that altered post-translational regulation of NCX1 contributes to the remodelling of its activity in HF. This evidence concerns the gene SLC8A1 and hydrops fetalis.