Because flavonoid compounds have been shown to bind the intracellular aryl hydrocarbon receptor (AhR) and activate the AhR signaling pathway, one suggestion to explain AF’s activity pattern is metabolic activation by the AhR and its target genes, specifically the 1A isoforms of cytochome P450 (CYP) enzymes [7,8,16,17]. The gene discussed is AHR; the disease is atrial fibrillation.