KCNN2 and atrial fibrillation: Among these, variants of KCNN3 are known to be associated with AF,[28] and SK channel subtype 2 (SK2) is known to be upregulated in failing human hearts and plays an important role in ventricular repolarization.[19,20] Although genetic variants are known to be associated with human cardiac arrhythmogenesis,[29,30] there are no reported associations between genetic variants of the KCNN2 gene and the risk of cardiac arrhythmias.