Family history was described as a risk factor for recurrent rehospitalization of patients with lone AF [17], and variants in 4q25, the angiotensin-converting enzyme (ACE) gene, CYP11B2 gene, and heme oxygenase-1 (HO-1) were shown to be associated with the recurrence of AF after catheter ablation [18], [19], [20]. This evidence concerns the gene ACE and atrial fibrillation.