Common risk factors that contribute to the development and progression of both AF and CAD are diabetes mellitus, hypertension, advancing age, dyslipidemia, obesity, smoking, and decreased physical activity [24] AF brings together several hemodynamic and systemic changes, including inflammation, oxidative stress, activation of the renin–angiotensin–aldosterone and sympathetic systems, as well as a prothrombotic state and endothelial dysfunction, which are also essential pathophysiological pathways in vascular atherosclerosis [13,27]. The gene discussed is REN; the disease is atrial fibrillation.