INTRODUCTION: Atrial fibrillation is the most common cardiac rhythm disorder whose incidence with age and which is responsible for high morbidity and mortality.

OBJECTIVE: Evaluate the thromboembolic risk of patients with atrial fibrillation and analyze the quality of the oral anticoagulation therapy at the Abidjan cardiology institute.

METHODS: This was a multicenter, retrospective and prospective cross-sectional study, with descriptive and analytical aims in 332 patients followed for atrial fibrillation diagnosed on the electrocardiogram.

RESULTS: Average age of 61 years (standard deviation = 16), with a female predominance with a sex ratio (M/F) of 0.93. The circumstances of discovery of atrial fibrillation were mainly palpitations (58.1%). Hypertension (57.8%). was the most frequently encountered comorbidity Underlying heart diseases were dominated by dilated cardiomyopathy (26.8%) and hypertensive heart disease (18.1%). The average CHA2DS2-VASc score was = 3.1 (standard deviation = 1.5) revealing a high level of thromboembolic risk (CHA2DS2-VASc score ≥2) in 76% of cases. The mean HAS-BLED score was =1.9 (SD =1.2). VKA were the main antithrombotic therapy prescribed in our patients and appeared of poor quality with a TTR <65% in the great majority of patients (93,75%) CONCLUSION: Atrial fibrillation is a condition responsible for the occurrence of thromboembolic complications when antithrombotic management is not correct. In this instance good oral anticoagulation is the best treatment to instaure. VKA are the most prescribed OAC in our context. The evaluation of the quality of anticoagulation by vitamin K antagonist is essential by one of its most used indices is the time spent in the therapeutic zone (TTR).