After adjustment for gender, age, smoking status, alcohol intake, BMI, systolic and diastolic blood pressure, creatinine, uric acid, LVEDD, LAD and LVEF, we observed that male gender, LAD and ACE gene DD genotype were the independent risk factors for lone AF, and that the ACE gene DD genotype had a 1.97-fold increased risk for lone AF compared with the ACE gene II+ID genotype (OR, 1.97; 95% CI, 1.15–3.37; P= 0.013; Table V). Here, ACE is linked to atrial fibrillation.