TBX5 and atrial fibrillation: PITX2 is strongly associated with AF and functionally implicated in atrial rhythm control (Kirchhof et al., 2011; Tao et al., 2014; Wang et al., 2010; Zhang et al., 2019), and was previously found to be a Tbx5 target in the left atrium (Nadadur et al., 2016).