ECG analysis revealed a high incidence of atrial fibrillation (AF), frequent AF episodes, and prolonged mean AF duration in circNAB1(+) mice following TAC and delivery of EGR1, Gadd45b, or Runx1, comparable to control vector delivered mice (Figure 5b; Figure S13a,b, Supporting Information). Here, GADD45B is linked to atrial fibrillation.