The purpose of this trial was to compare the long-term efficacy of low-dose amiodarone with losartan and perindopril (both combined with low-dose amiodarone) for the prevention of atrial fibrillation (AF) recurrence in patients with lone paroxysmal AF. One-hundred and seventy-seven patients with lone paroxysmal AF were randomly assigned to three treatment groups: group 1 received low-dose amiodarone alone, group 2 received low-dose amiodarone plus losartan, and group 3 received low-dose amiodarone plus perindopril. Left atrial diameter was measured with transthoracic echocardiogram at baseline and 6, 12, 18, and 24 months after randomization. The primary endpoint was the incidence of AF documented by 12-lead ECG or Holter after 14 days and within 24 months after randomization. The primary endpoint was reached in 24 patients (41%) in group 1, 11 (19%) in group 2, and 14 (24%) in group 3 (P = 0.02). The Kaplan-Meier survival analysis demonstrated a significant reduction in AF recurrence in group 2 (P = 0.006, log-rank test) as well as in group 3 (P = 0.04, log-rank test) when compared with group 1. No difference in the AF recurrence-free survival was found between group 2 and group 3. After 24 months follow-up, the left atrial diameter in group 2 and group 3 was significantly smaller than that in group 1 (36 +/- 2.3 and 35 +/- 2.4 vs. 38 +/- 2.4 mm, P < 0.001 for both comparisons). The results of this study suggest that the combination of perindopril or losartan with low-dose amiodarone is more effective than low-dose amiodarone alone for the prevention of AF recurrence in patients with lone paroxysmal AF. Adding losartan or perindopril to amiodarone can inhibit left atrial enlargement in this group of patients.