PITX2 and atrial fibrillation: Although the entire scope of the activities and interactions of PITX2 are yet to be elucidated, it is clear that PITX2 has important functions in the adult left atrium and there is evidence in animal models that reduced Pitx2 mRNA levels predispose atria to AF by changing its electrical function, whether by abnormal pacemaker activity or adverse electrical remodelling.