Overt and subclinical hypothyroidism also increased the risk of post-operative-AF in the patients after cardiac surgery187–189 At the molecular level, hypothyroidism was associated with increased serum levels of CRP, TNF-1α, IL-6, and TGF-β1 in rats, induced secretion of the cardiac stress markers ANP, brain natriuretic peptide (BNP) (regulated by TH) and cardiac troponin-T.175. This evidence concerns the gene TGFB1 and atrial fibrillation.