PPARA and atrial fibrillation: In addition, KEGG pathway analysis showed that the green module gene was mainly enriched in the calcium signaling pathway, cAMP signaling pathway, and PPAR signaling pathway, while the pink module gene was mainly enriched in the TGF-β signaling pathway, suggesting that the main causes of AF were abnormal calcium homeostasis, energy metabolism, and fibrosis, which is consistent with previous studies (7, 8, 19, 20).