TGFB1 and atrial fibrillation: There was also a strong and positive correlation between larger LA volume and MIP-1α level (r = 0.461, p < 0.001), and a negative correlation between larger LA volume and TGF-β1 level (r = −0.292, p= 0.032) and between large LA volume and TGF-β3 level (r = −0.279, p = 0.041) in patients with AF.