RYR2 and hydrops fetalis: The increased diastolic leak of Ca2+ in HF may contribute to destabilisation of Em and together with the increase in NCX could lower the threshold for DADs, so that even a modest diastolic leak from RyR2 may result in an increased propensity to trigger a fatal arrhythmia (Pogwizd & Bers, 2002; Scoote & Williams, 2004; Fauconnier et al., 2005; Sipido & Eisner, 2005).