We have also determined, by blocking NCX with 10 mmol/l Ni2 + and measuring the rate of decay of the caffeine evoked rise of [Ca2 +]i, that the contribution of PMCA to Ca2 + extrusion is no different between control and HF atrial myocytes (kPMCA: control, 1.17 ± 0.04 s− 1; HF, 1.09 ± 0.01 s− 1). Here, TLX2 is linked to hydrops fetalis.