Although the specificmechanisms through which pulmonary vein lesions lead to atrial fibrillation areunclear, Yu-Ki Iwasaki and colleagues demonstrated in animal experiments thatfibrosis of the pulmonary veins can induce atrial fibrillation, with detectedexpression of platelet-derived growth factor (PDGF)-C and vascular endothelialgrowth factor (VEGF) in fibrotic pulmonary veins [18]. The gene discussed is PDGFC; the disease is atrial fibrillation.