Importantly, the Pitx2 locus harbors genomic variation that contributes to inherited susceptibility to atrial fibrillation, an arrhythmia that is triggered by focal firing from the region of the pulmonary venous myocardium and left-sided SAN remnant (Roselli et al., 2018; Zhang et al., 2019). This evidence concerns the gene PITX2 and atrial fibrillation.