Park S, Lee S, Kim Y, et al. - In this study, the causal impacts between atrial fibrillation (AF) and renal function were inquired. A bidirectional summary-level Mendelian randomization analysis was conducted implementing the findings from a large-scale genome-wide association study for estimated glomerular filtration rate (eGFR) by the CKDGen (N = 765 348) and AF (N = 588 190) to determine genetic instruments. A significant link of a genetic predisposition to AF, with reduced eGFR as well as with elevated risk of chronic kidney disease, was identified. AF was identified as a causal risk factor for renal function impairment. However, findings did not demonstrate an impact of renal function on AF.