SOD3 and atrial fibrillation: HM contained significantly higher levels of both SOD isoforms compared to AF (AF vs. HM: 35.6 (1.9–172.3) vs. 267.9 (54.6–843.8), p < 0.001 for SOD1 and 1.2 ng/mL (0.1–26.5) vs. 5.5 ng/mL (0.1–300.0), p < 0.001 for SOD3), regardless of GA.