Based on the variance accounted for (VAF) score, a ratio of indirect-to-total effect [25], we identified that GPR43/NLRP3 mediated 68.88% indirect effect on the effect of fecal acetic acid on AF (Fig. 6A) and indirect effect of LAD between GPR43/NLRP3 and AF was 21.27% (Fig. 6B). This evidence concerns the gene FFAR2 and atrial fibrillation.