KCNJ11 and atrial fibrillation: KATP channel opening is protective in the process of ischemic preconditioning, although debate exists as to whether this is due to effects on sarcolemmal or mitochondrial KATP channels.42 Loss of KATP function in Kir6.2 knockout mice has been shown to promote triggered activity in the form of early afterdepolarizations with isoproterenol challenge, and a similar mechanism of otherwise lone AF demonstrated due to a missense mutation in ABCC9 encoding SUR2A.43,44