Slower and wider Ca2+ waves observed in failing cells in the present study would lead to prolonged depolarization time required for Na/Ca exchanger activation and thus they are more likely to result in the formation of delayed afterdepolarizations observed in failing atrial.43,44 Along with elevated diastolic [Ca2+]i and SR Ca2+ overload, observed in HF, it would result in the formation of foci of triggered ectopic activity located within areas of significant T-tubular degradation. Here, SLC8A1 is linked to hydrops fetalis.