Objective: To evaluate the effect of angiotensin-converting enzyme inhibitor (ACEI)/angiotensin II receptor blocker (ARB) therapy on the prognosis of patients with atrial fibrillation (AF).Methods: A total of 1, 991 AF patients from the AF registry were divided into two groups according to whether they were treated with ACEI/ARB at recruitment. Baseline characteristics were carefully collected and analyzed.