To achieve this, in this study a robust computer model of human atrial cellular kinetics (TPA) based on the ten Tusscher-Panfilov (TP) ventricular cell model37 was developed, validated, and utilized to systematically illustrate the cellular and molecular mechanisms underlying spontaneous AF in patients with TBX5/PITX2 insufficiency. This evidence concerns the gene PITX2 and atrial fibrillation.