Patients with persistent AF had higher TGF-β1 levels than that in paroxysmal AF patients (SMD 0.57; 95%CI 0.22–0.92) without significant heterogeneity (I2 = 30%, P = 0.23) across studies (Fig 4). The gene discussed is TGFB1; the disease is Paroxysmal atrial fibrillation.