This brings to the concept of AFib treatment while interfering on tissue remodeling by the way of renin-angiotensin system. Drugs such as the angiotensin converting enzyme inhibition [ACEI] may reduce AFib in patients with heart failure. No randomized study so far has compared the ACEI drugs against placebo among high-risk patients of AFib in post AFL RFA area. On the basis of experimental and clinical study, the investigators seek to evaluate the ACEI use in the prevention of AFib in an AFL post RFA ablation.