SLC8A1 and heart failure: Increased expression of NCX1 has also been linked with pathological hypertrophy and heart failure (reviewed in Sipido et al., 2002), whereby elevated NCX1 is thought to compensate for defective ECC and depressed function of SERCA but also produce arrhythmogenic-delayed after-depolarisations (Gómez et al., 1997; Schultz et al., 2004; Venetucci et al., 2007).