Causal association between myocardial infarction and atrial fibrillation: A bidirectional Mendelian randomization study

Abstract Background At present, many studies have shown a significant correlation between myocardial infarction (MI) and atrial fibrillation (AF), but few focus on the bidirectional causal relationship between MI and AF. Therefore, this Mendelian randomization (MR) study was designed to examine the bidirectional causality between MI and AF.Methods We used the publicly available summary statistical dataset of MI from genome-wide analysis studies (GWAS; ebi-a-GCST011364; case = 14,825, control = 2,680). The summary statistical dataset of AF was obtained from a European population GWAS (finn-b-I9_AF_REIMB; case = 10,516, control = 116,926). A two-sample bidirectional MR analysis was performed using analysis methods including inverse-variance weighted (IVW), MR-Egger, and weighted median.Results In site-specific MI analyses, we screened 30 single nucleotide polymorphisms (SNPs) from GWAS as instrumental variables (IVs). Causal association between MI and AF can be supported by IVW (beta = 0.349, SE = 0.057, P < 0.001), MR-Egger (beta = 0.398, SE = 0.131, P = 0.005), and weighted median (beta = 0.352, SE = 0.068, P < 0.001). In the reverse MR analyses, we screened 20 SNPs as IVs and the casual effect of AF on MI was observed by IVW (beta = 0.047, SE = 0.022, P = 0.033).Conclusions Our MR study results showed a good causal effect of MI on AF. The MR analysis also found a causal effect of AF on MI.