After adjustment for a variety of risk factors, the ACE gene DD genotype had a 1.97-fold increased risk for lone AF (OR, 1.97; 95% CI, 1.15–3.37; P= 0.013) and 2.35-fold increased risk for AF recurrence (RR, 2.35; 95% CI, 1.10–5.04; P=0.028) compared with the ACE gene II+ID genotype. Here, ACE is linked to atrial fibrillation.