Introduction: Atrial fibrillation (AF) is the most widespread arrhythmia, which increases with the aging of population. The frequency of ischemic stroke in patients with non-rheumatic form of AF is 5% per year that is by 2-7 times more than in patients without AF. [O.Y. Zharinov, 2011] This type of disorganization of heart beat is one of the most important factors of thromboembolic complications and heart failure in patients with cardiac disease [A.S.Sychev, 2011]. Purpose: For identifying markers of AF we have examined 20 patients with stable angina of the IIIrd functional class (FC III). Group I consisted of the patients with AF, group II consisted of the patients without AF. Supervised groups were identical, according to gender and age of the participants. The average age of the patients was 50.2. According to Framingham study, 0.3-0.4% of adults suffers from various forms of AF, reaching 8.8% of people aged over 80 years. Many epidemiological studies: Framingham study, MRIFT, EVA, MONICA, were conducted to determine the prevalence of coronary heart disease and risk factors for its development. However the studies of AF on the population’s level are rarely conducted. Methods: All patients were determined by body mass index (BMI), Kerdo index, held echocardiography and biochemical parameters of blood and urine. Software StatSoft Statistics 8.0 (average arithmetic, standard errors, Student’s t-test, the Kolmogorov-Smirnov test, U-Mann-Whitney test) were used to process the survey results. Results: We have identified the likely (p<0,01) differences in the groups during comparison. Thus, patients from group II appeared to have significantly higher body weight, BMI was higher than 25, the highest Kerdo index, signs of the left ventricular hypertrophy. The patients with AF have a high prevalence of risk factors: 2/3 of patients have hypertension, hypercholesterolemia, 25% are smokers, half of the surveyed patients with AF conduct sedentary lifestyle, all patients have excess body weight, left ventricular hypertrophy, increasing of the activation of sympathoadrenal system. Conclusion: Early identification of persons at AF risk can prevent the development of arrhythmias and stroke and therefore a decrease of cardiac and cerebral death.