Fig. 6A, the IL-6 level in atria was significantly increased again on day 3 after the supplementation of IL-6. Meanwhile, supplementation with IL-6 markedly increased the total AF duration (Fig. 6B) and the probability of AF induction (Fig. 6C). Conduction in the atria was also assessed in spontaneously beating and stimulated hearts using multi-electrode array mapping (Fig. 6D–G). Consistent with our recent findings , SP rats treated with vehicle show severe disruption of conduction homogeneity as demonstrated by the increased inhomogeneity index. However, the inhomogeneity index decreased after treatment with colchicine but increased again after supplementation with IL-6. Of note, there was no significant difference in conduction velocity among groups. In addition, the phosphorylation of STAT3 also increased again after supplementation with IL-6 (Fig. 6H,I). These results suggest that colchicine prevents POAF by inhibiting the expression of IL-6.