Atrial fibrillation (AF) is a leading cause of cardiovascular mortality and morbidity. Asian patients with AF have a higher rate of major bleeding including intracranial hemorrhage (ICH) compared to non-Asians. Non-vitamin K antagonist oral anticoagulants (NOACs) are the safer drugs compared to warfarin due to a lower rate of ICH, but the rate of NOACs use in many Asian AF is much lower than non-Asian countries due to economic concerns. The purpose of the COhort of antithrOmbotic use and cLinical outcomes in patients with Atrial Fibrillation (COOL-AF) Phase 2 registry is to determine the changes in antithrombotic patterns and the impact on clinical outcomes. The COOL-AF Phase 2 study is a prospective observational multicenter study of patients with known or newly diagnosed non-valvular AF in Thailand. The aim is a sample size is 3680 patients from 33 centers within a 2-years enrollment timeline. Patients will be follow-up every 6 months until 3 years. The study outcomes were death, ischemic stroke/systemic embolism, major bleeding, myocardial infarction, heart failure, and quality of life.