For example, a previous study showed that AF recurrence rates were 85.2% in patients with large LAD and 60% in patients with small LAD and high plasma TGF-β1 concentration, suggesting that LAD alone is not predictive of AF recurrence.[20] The current study, finding that serum TGF-β1 concentration, but not LAD, correlated with left atrial fibrosis, indicates that local atrial fibrosis does not result in LA enlargement. Here, TGFB1 is linked to atrial fibrillation.