Introduction: Although we have known for almost last few years that Atrial fibrillation has been increasing by patients in Mongolia. Atrial fibrillation, the most common sustained chronic arrhythmia, with atrial rates of 200-500 beats per minute in patients. Most patients atrial fibrillation have structural heart disease such us mitral stenosis or regurgitation, acute myocardial infarction, Wolff-Parkinson-White syndrome, thyrotoxicosis, recent cardiothoracic surgery, cardiomyopathy, myocarditis or pulmonary disease. Atrial Fibrillation increases the risk of stroke, thromboemboli and mortality of adults with structural heart disease [4]. The symptoms most frequently reported by patients with atrial fibrillation is a rapid, irregullar heartbeat, chest pain, shortness of breath, lightheadedness and dizziness. Goal: For that reason we decided to research patients with atrial fibrillation who are treated by the inpatient cardiology department of General hospital of defense and Law Enforcement between 2010-2014 years. Conclusion
1. The hospitalized patients are observed only 6 cases of atrial fibrillation in 2010 years, even though the prevalence of atrial fibrillation has been increasing 75 cases in 2014 years, as a result it developed 30% during 4 years in hospitalized patients
2. CHA2DS2-VАSc score was high risk of stroke /62.5% of them /most patients with both paroxysmal and chronic atrial fibrillation should be anticoagulated to reduce the occurrence of thromboemboli
3. HAS-BLЕD score has became highest rick of bleeding /32.7% of all patients. For the reason we should be select correctly drugs for patients an anticoagulation treatment and they are controled INR every month