In the sinus node of the heart failure mice, there was no change in the mRNA for various components of the intracellular Ca2+ clock (RyR2, SERCA2, calsequestrin and NCX1; Supplementary Figs. 3 and 5) and no change in the mRNA for related Ca2+ channel subunits (Cav1.2, Cavα2δ2; Supplementary Fig. 3). Here, SLC8A1 is linked to heart failure.