Moreover, both the CPVT-linked RyR2-R2474S channel10, which is also in a primed state, as well as the RyR2 channels depleted of calstabin-2, promote atrial fibrillation3,26,69,70 suggesting that the primed state reached by these channels explains the occurrence of arrythmias in HF as well as in CPVT and atrial fibrillation. The gene discussed is FKBP1B; the disease is hydrops fetalis.