FKBP1B and cardiac arrhythmia: 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.