SOD1 and atrial fibrillation: After classification of the AF patients into PAF and PeAF patients, we observed a high heart failure (HF) rate, increased levels of LAD, elevated serum concentrations of BNP, MDA, TNF-α, IL-6, CTX-I, TGF-β1, and lower expression of SOD (P<0.05) in PeAF patients than in PAF patients.