There was also a strong, positive correlation between higher AHRE burden and larger LA diameter and volume, and a strong, positive correlation between higher AHRE burden and decreased mRNA expression of BMAL1, CRY1, CRY2, NR1D1, NR1D2, PER2, PER3, RORA, RORB, RORC, and TIM in patients with AF (all p < 0.05) (Table 2). This evidence concerns the gene PER2 and atrial fibrillation.