This is an international observational multicentre study to be conducted in Germany, Spain, Italy and USA. The main objective of the study is to evaluate the relative effectiveness of dronedarone in real world clinical practice versus other anti-arrhythmic agents of interest. The design of the study is a historic-prospective cohort with dynamic exposure and stratified competitive recruitment with balanced comparison groups of dronedarone versus alternative antiarrhythmic drugs of interest.

Inclusion Criteria:

• Patient 18 years old or above
• Patient with paroxysmal or persistent atrial fibrillation
• Patient using an AAi (antiarrhythmic drug of interest) or dronedarone (index drug)
• Patient's treatment changed from one AAi to another AAi or dronedarone OR from no antiarrhythmic therapy to the start of AAi or dronedarone therapy during previous 6 months before the date of recruitment
• Patient with at least 6 months of medical and treatment information prior to the start of the index drug
• Patient able to answer the telephone interview in a language of the participating country: English, German, Italian or Spanish (with or without proxy).

Exclusion Criteria:

• Patient with heart failure (NYHA class IV)
• Patient with permanent Atrial Fibrillation
• Patient with psychiatric conditions preventing the participation to the study according to the physician

This is an international observational multicentre study to be conducted in the following four countries: Germany, Spain, Italy and USA. Patients will be will be recruited from cardiology clinics, both hospital and non-hospital based, depending on particulars of treatment pathway of ppAF patients in each country.