Inclusion Criteria:

* Minimum age of 18 years

* Medically stable and appropriate for chronic antithrombotic treatment

* Atrial fibrillation eligible to receive anticoagulation

* Participant must satisfy one or both of the following categories of risk factors (a or b): a) one or more of the following risk factors: i) age greater than or equal to 75 years, ii) history of any type of stroke including symptomatic stroke of any kind. b) two or more of the following risk factors: i) age between 65 and 74 years, ii) hypertension, iii) diabetes mellitus, iv) atherosclerotic vascular disease, v) heart failure

Exclusion Criteria:

* Hemodynamically significant valve disease or those with valve disease that will potentially require surgical valve replacement during the study

* Any condition other than AF that requires chronic anticoagulation