Atrial fibrillation is the most common arrhythmia in clinic. It can lead to heart failure or stroke, and has a high disability rate and mortality rate. At present, although radiofrequency ablation can cure atrial fibrillation, the success rate is only 50~70%, and has a high recurrence rate. In recent decades, no effective new antiarrhythmic drugs have been introduced, but there are side effects in long-term application of the existing antiarrhythmic drugs. Therefore, it is urgent to provide new and effective antiarrhythmic drugs.

Autophagy level of atrial myocytes in atrial fibrillation patients was significantly higher than that in sinus rhythm. Hydrochloroquine (HCQ) is a hydroxychloroquine sulfate composed of 4- amino quinoline compounds. As an effective inhibitor for autophagy, HCQ could effectively prevent the increased autophagy level of atrial myocytes in atrial fibrillation rabbits, prevent atrial effective refractory period (AERP) shortening, and decrease the rate and duration of atrial fibrillation.

At present, hydroxychloroquine is mainly used in the treatment of rheumatic immune system diseases and anti malaria. Because of its good safety and small side effects, HCQ has become an indispensable member of drugs in the combined treatment of rheumatoid arthritis and systemic lupus erythematosus patients. In recent years, studies have reported that hydroxychloroquine plays an important role in the prevention and treatment of cardiovascular diseases. Chloroquine could effectively shorten the action potential of atrial myocytes by blocking the inward rectifier potassium ion channel (Kir2.1) and reducing the inward potassium ion current Ik1. HCQ could also reduce 72% (P=0.002), and 70% for the risk of coronary heart disease, stroke, and transient ischemic disease. So the investigators speculate that HCQ may be a potential drug to block the occurrence of acute atrial fibrillation.

Inclusion Criteria:

• Successful radiofrequency ablation of atrial fibrillation within 24 hours

Exclusion Criteria:

• History of cerebrovascular disease: ischemic stroke, cerebral haemorrhage and transient ischemic attack.
• History of cardiovascular disease:unstable angina, myocardial infarction, coronary revascularization and congestive heart failure.
• History of renal impairment.
• History of Type I diabetes mellitus or Type II diabetes uncontrolled.
• History of liver impairment.
• History of alcoholism or drug abuse.
• Known severe skin rash or damage.
• Known retinal pigmentation and visual field defect.
• Allergy to any component of hydroxychloroquine.