PITX2 and atrial fibrillation: In the presence of 2 μM flecainide, a planar wave slowly propagated and then produced a spiral wave within a shorter VW (294.7–296 ms) (S7B Fig and S2 Video). However, this re-entrant wave self-terminated at 8450 ms and no triggered activity occurred (Fig 5H). Thus, the efficacy of flecainide in suppressing Pitx2-induced AF may be attributed to its effects on triggered activity and WL.